Robert J Schneider, Ph.D.

The role of health system factors in delaying final diagnosis and treatment of breast cancer in Mexico City, Mexico
Bright, Kristin; Barghash, Maya; Donach, Martin; de la Barrera, Marcos Gutierrez; Schneider, Robert J; Formenti, Silvia C
2011 Apr;20 Suppl 2:S54-S59, Breast
In Mexico, breast cancer is the leading cancer-related death among women and most cases are diagnosed at advanced stages (50-60%). We hypothesized health system factors could be partly responsible for this delay and performed a prospective review of 166 new breast cases at a major public hospital in Mexico City. Our analysis confirmed the prevalence of locally advanced and metastatic disease (47% of patients). A subset analysis of 32 women with confirmed stage I-IIIC breast cancer found an average time interval of 1.8 months from symptom onset to first primary care consultation (PCC), with an additional 6.6 months from first PCC to confirmed diagnosis, and 0.6 months from diagnosis to treatment initiation. Patients underwent an average of 7.9 clinic visits before confirmed diagnosis. Findings suggest that protracted referral time from primary to specialty care accounts for the bulk of delay, with earlier stage patients experiencing longer delays. These findings reveal a critical need for further study and exploration of interventions
— id: 130301, year: 2011, vol: 20 Suppl 2, page: S54, stat: Journal Article,

Over-expression of translation initiation factor EIF4G confers robust radioresistance to the cancer stem cell population in inflammatory breast cancer
Connolly E.P.; Silvera D.; Badura M.L.; Venuto T.; Schneider R.J.
2011 ;81(2 SUPPL 1):S85-S85, International journal of radiation oncology biology physics
Purpose/Objective(s): Inflammatory breast cancer (IBC) is a highly aggressive and radiation resistant malignancy with a dismal prognosis despite multimodality therapy including ionizing radiation (IR). We showed that the unique pathogenic properties of IBC result in part from over-expression of translation initiation factor eIF4G, which is also over-expressed in other advanced breast cancers. We previously demonstrated that the kinase mTOR responds to IR through the DNA-damage response (DDR) pathway to regulate protein synthesis. Many key proteins required for the DDR pathway are encoded by mRNAs that require high levels of eIF4G and mTOR activity for their efficient translation. Here we tested whether upregulation of eIF4G is crucial for the radio-resistance of IBC. Materials/Methods: Experiments were conducted using IBC SUM149 cells. eIF4G was silenced by stable inducible shRNAs. Radiation sensitivity was determined by clonogenic survival assays. IBC tumor xenografts were generated in nude mice, eIF4G silenced in tumors at 150 mm3 and then treated by 3 fractions of IR 1 week later. Cancer stem cells (CSCs) from cell culture and tumors were analyzed by of FACS, mammosphere formation and Aldefluor assays. Results: High levels of eIF4G mediated strong radio-resistance in IBC tumors. Moderate eIF4G inhibition prevented IBC xenograft tumor growth by strongly enhanced radiosensitivity. Strikingly, in contrast with non-transformed breast epithelial cells, reducing the high levels of eIF4G in IBC cells provided no enhancement in radiation sensitivity. Rather, the radio-sensitive population was found to be largely the CSCs. Importantly, we demonstrate that reduction of eIF4G levels acutely radio-sensitizes the CSC population within IBC tumor xenografts. Radio-resistance of IBC cells was mediated by signaling through S6K and selective mRNA translation of proteins involved in the DDR and survival pathways. Conclusions:We demonstrate that the overexpression of eIF4G found in IBC and other advanced breast cancers provides selective mRNA translation of proteins involved in the DDR and survival pathways and plays an important role in radiation resistance. Inhibition of eIF4G selectively and strongly enhances radiation sensitivity of the extremely radiation resistant CSC population. Targeting translational control of the breast CSC population provides a feasible opportunity to reverse radiation resistance of advanced breast cancer. Small molecule inhibitors of these translation factors are under development in the laboratory
— id: 150897, year: 2011, vol: 81, page: S85, stat: Journal Article,

TORC1/2 inhibition with concurrent radiation controls inflammatory breast cancer in a preclinical animal model through selective blockade of translation
Connolly E.P.; Silvera D.; Venuto T.; Sawai A.; Schneider R.J.
2011 ;81(2 SUPPL 1):S751-S751, International journal of radiation oncology biology physics
Purpose/Objective(s): The PI3K/AKT/mTOR pathway is frequently deregulated in human cancers, including inflammatory breast cancer (IBC). mTOR (mammalian target of rapamycin) is a key regulator of protein synthesis; it links mRNA translation to the metabolic state of the cell and plays a key role in the signaling of malignant cell growth, proliferation, differentiation, migration, and survival. We have shown that mTOR activation following treatment with DNA damaging agents such as ionizing radiation (IR) is a primary protector of advanced breast cancer cells, including IBC cells. In these cells IR selectively increases translation of mRNAs for survival and DNA repair genes, including survivin, PARP, and DNA repair enzymes.We hypothesized that treatment with an mTOR inhibitor coupled with IR would provide a synergistic ability to control IBC.We examined the cytotoxic effects of combining mTOR inhibition and radiation in an IBC xenograft model, using either the catalytic mTORC1/2 inhibitor pp242, or allosteric mTORC1 inhibitor RAD001 (Everlimus). Materials/Methods: Experiments were conducted in SUM149 IBC cells. Cells were treated with RAD001 or pp242 alone or in combination with increasing IR from 0-8 Gy. In vitro studies preformed included: cell survival assay, immunoblot analysis, 35Smethionine labeling, cell cycle analysis by FACs, and caspase-3 activity assay. In vivo studies were performed in a SUM149 xenograft nude mouse model. Animals were treated with RAD001 and pp242 individually or in combination with IR and tumor growth was monitored. IHC, immune-fluorescence and TUNEL assays were also performed. Results: pp242 inhibited both mTORC1/2 signaling in IBC cells and blocked feedback upregulation of AKT and ERK, while RAD001 inhibited only mTORC1 and activated AKT through up-regulation of mTORC2. pp242 when combined with IR showed significantly greater tumor control in IBC xenografts and strongly enhanced radio-sensitivity in vitro, in contrast to RAD001, which had no added effect. Combining pp242 with IR promoted apoptosis, inhibition of both endogenous and radiation-induced AKT activation, and greater inhibition of mTOR signaling to its downstream effectors. This combination more efficiently inhibited overall translation, and likely blocks translation of specific mRNAs involved in DNA repair and survival functions. Conclusions: These studies demonstrate that targeted inhibition of mTORC1/2 synergizes with IR in a model system of IBC. Mechanistically, mTORC1/2 inhibition combined with IR increases apoptosis, prevents radiation induced pro-survival signals mediated through constitutively active AKT and selectively blocks translation of survival and DNA response mRNAs
— id: 150890, year: 2011, vol: 81, page: S751, stat: Journal Article,

Targeting the mTOR/4E-BP Pathway in Endometrial Cancer
Korets, Sharmilee Bansal; Czok, Sarah; Blank, Stephanie V; Curtin, John P; Schneider, Robert J
2011 Dec 15;17(24):7518-7528, Clinical cancer research
Endometrial cancer is the most common gynecologic malignancy. Although it is highly treatable in the early stages of disease, therapies for advanced and recurrent disease are rarely curative. A molecular and genetic understanding of endometrial cancer involves the mTOR signaling pathway, an emerging target for treatment of type I disease (the most common presentation). Endometrial cancers show a significant reliance on the mTOR pathway for survival, and studies to date have revealed a clinical advantage in targeting this pathway. Less well developed in the study of endometrial cancer is an understanding of mTOR signaling to its major downstream effector, translational control. Given the poor rate of success for treatment of late-stage endometrial cancer, increasing attention is being directed to the development of new therapeutic approaches, including targeting the mTOR pathway. Here, we discuss the potential benefit of targeting mTOR combined with existing chemotherapies by monitoring its impact on translational regulatory pathways and key translation targets in endometrial cancer. We also highlight laboratory and clinical research findings that will provide new avenues for future research and clinical development. Clin Cancer Res; 17(24); 7518-28. (c)2011 AACR
— id: 147690, year: 2011, vol: 17, page: 7518, stat: Journal Article,

Distinct function of androgen receptor coactivator ARA70alpha and ARA70beta in mammary gland development, and in breast cancer
Wu, Xinyu; Chen, Fei; Sahin, Aysegul; Albarracin, Constance; Pei, Zhiheng; Zou, Xuanyi; Singh, Baljit; Xu, Ruliang; Daniels, Garrett; Li, Yirong; Wei, Jianjun; Blake, Marvin; Schneider, Robert J; Cowin, Pamela; Lee, Peng
2011 Jul;128(2):391-400, Breast cancer research & treatment
Steroid receptor coactivators are important in regulating the function of the receptors in endocrine organ development and in cancers, including breast. Androgen receptor (AR) coactivator ARA70, was first identified as a gene fused to the ret oncogene and later characterized as an AR coactivator. We previously reported that the full length ARA70alpha functions as a tumor suppressor gene and that ARA70beta functions as an oncogene in prostate cancer. Here we show that both ARA70alpha and ARA70beta function as AR and estrogen receptor (ER) coactivators in breast cancer cells. However, ARA70alpha and ARA70beta serve different functions in mammary gland development and breast cancer tumorigenesis. We observed hypoplastic development of mammary glands in MMTV driven ARA70alpha transgenic mice and overgrowth of mammary glands in ARA70beta transgenic mice at virgin and pregnant stages. We determined that ARA70alpha inhibited cell proliferation, and that ARA70beta promotes proliferation in MCF7 breast cancer cells. These effects were observed in hormone-free media, or in media with androgen or estrogen, though to varying degrees. Additionally, we observed that ARA70beta strongly enhanced the invasive ability of MCF7 breast cancer cells in in vitro Matrigel assays. Significantly, decreased ARA70alpha expression is associated with increased tendency of breast cancer metastasis. In summary, ARA70alpha and ARA70beta have distinct effects in mammary gland development and in the progression of breast cancer
— id: 138162, year: 2011, vol: 128, page: 391, stat: Journal Article,

Preoperative concurrent paclitaxel-radiation in locally advanced breast cancer: pathologic response correlates with five-year overall survival
Adams, Sylvia; Chakravarthy, A Bapsi; Donach, Martin; Spicer, Darcy; Lymberis, Stella; Singh, Baljit; Bauer, Joshua A; Hochman, Tsivia; Goldberg, Judith D; Muggia, Franco; Schneider, Robert J; Pietenpol, Jennifer A; Formenti, Silvia C
2010 Dec;124(3):723-732, Breast cancer research & treatment
We have previously demonstrated high pathologic response rates after neoadjuvant concurrent chemoradiation in patients with locally advanced breast cancer (LABC). We now report disease-free survival (DFS) and overall survival (OS) in the context of pathologic response. 105 LABC patients (White 46%, Non-White 54%) were treated with paclitaxel (30 mg/m(2) intravenously twice a week) for 10-12 weeks. Daily radiotherapy was delivered to breast, axillary, and supraclavicular lymph nodes during weeks 2-7 of paclitaxel treatment, at 1.8 Gy per fraction to a total dose of 45 Gy with a tumor boost of 14 Gy at 2 Gy/fraction. Pathological complete response (pCR) was defined as the absence of invasive cancer in breast and lymph nodes and pathological partial response (pPR) as the persistence of <10 microscopic foci of invasive carcinoma in breast or lymph nodes. Pathologic response (pCR and pPR) after neoadjuvant chemoradiation was achieved in 36/105 patients (34%) and was associated with significantly better DFS and OS. Pathological responders had a lower risk of recurrence or death (HR = 0.35, P = 0.01) and a longer OS (HR = 4.27, P = 0.01) compared with non-responders. Median DFS and OS were 57 and 84 months for non-responders, respectively, and have not yet been reached for responders. Importantly, pathologic response was achieved in 54% of patients with HR negative tumors (26/48). In conclusion, pathologic response to concurrent paclitaxel-radiation translated into superior DFS and OS. Half of the patients with HR negative tumors achieved a pathologic response
— id: 114178, year: 2010, vol: 124, page: 723, stat: Journal Article,

Identification of markers of taxane sensitivity using proteomic and genomic analyses of breast tumors from patients receiving neoadjuvant paclitaxel and radiation
Bauer, Joshua A; Chakravarthy, A Bapsi; Rosenbluth, Jennifer M; Mi, Deming; Seeley, Erin H; De Matos Granja-Ingram, Nara; Olivares, Maria G; Kelley, Mark C; Mayer, Ingrid A; Meszoely, Ingrid M; Means-Powell, Julie A; Johnson, Kimberly N; Tsai, Chiaojung Jillian; Ayers, Gregory D; Sanders, Melinda E; Schneider, Robert J; Formenti, Silvia C; Caprioli, Richard M; Pietenpol, Jennifer A
2010 Jan 15;16(2):681-690, Clinical cancer research
PURPOSE: To identify molecular markers of pathologic response to neoadjuvant paclitaxel/radiation treatment, protein and gene expression profiling were done on pretreatment biopsies. EXPERIMENTAL DESIGN: Patients with high-risk, operable breast cancer were treated with three cycles of paclitaxel followed by concurrent paclitaxel/radiation. Tumor tissue from pretreatment biopsies was obtained from 19 of the 38 patients enrolled in the study. Protein and gene expression profiling were done on serial sections of the biopsies from patients that achieved a pathologic complete response (pCR) and compared to those with residual disease, non-pCR (NR). RESULTS: Proteomic and validation immunohistochemical analyses revealed that alpha-defensins (DEFA) were overexpressed in tumors from patients with a pCR. Gene expression analysis revealed that MAP2, a microtubule-associated protein, had significantly higher levels of expression in patients achieving a pCR. Elevation of MAP2 in breast cancer cell lines led to increased paclitaxel sensitivity. Furthermore, expression of genes that are associated with the basal-like, triple-negative phenotype were enriched in tumors from patients with a pCR. Analysis of a larger panel of tumors from patients receiving presurgical taxane-based treatment showed that DEFA and MAP2 expression as well as histologic features of inflammation were all statistically associated with response to therapy at the time of surgery. CONCLUSION: We show the utility of molecular profiling of pretreatment biopsies to discover markers of response. Our results suggest the potential use of immune signaling molecules such as DEFA as well as MAP2, a microtubule-associated protein, as tumor markers that associate with response to neoadjuvant taxane-based therapy
— id: 109144, year: 2010, vol: 16, page: 681, stat: Journal Article,

Inflammatory Breast Cancer Radio-resistance and its Cancer Stem Cell Population are Oppositely Controlled by Translation Factor elF4G
Connolly, E. P.; Silvera, D.; Badura, M. L.; Braunstein, S. E.; Formenti, S. C.; Schneider, R. J.
2010 OCT 13 ;78(3):S221-S221, International journal of radiation oncology biology physics
— id: 114017, year: 2010, vol: 78, page: S221, stat: Journal Article,

Low-dose radiation augments vasculogenesis signaling through HIF-1-dependent and -independent SDF-1 induction
Lerman, Oren Z; Greives, Matthew R; Singh, Sunil P; Thanik, Vishal D; Chang, Christopher C; Seiser, Natalie; Brown, Daniel J; Knobel, Denis; Schneider, Robert J; Formenti, Silvia C; Saadeh, Pierre B; Levine, Jamie P
2010 Nov 4;116(18):3669-3676, Blood
The inflammatory response to ionizing radiation (IR) includes a proangiogenic effect that could be counterproductive in cancer but can be exploited for treating impaired wound healing. We demonstrate for the first time that IR stimulates hypoxia-inducible factor-1alpha (HIF-1alpha) up-regulation in endothelial cells (ECs), a HIF-1alpha-independent up-regulation of stromal cell-derived factor-1 (SDF-1), as well as endothelial migration, all of which are essential for angiogenesis. 5 Gray IR-induced EC HIF-1alpha and SDF-1 expression was greater when combined with hypoxia suggesting an additive effect. While small interfering RNA silencing of HIF-1alpha mRNA and abolition of HIF-1alpha protein induction down-regulated SDF-1 induction by hypoxia alone, it had little effect on SDF-1 induction by IR, demonstrating an independent pathway. SDF-1-mediated EC migration in hypoxic and/or radiation-treated media showed IR induced strong SDF-1-dependent migration of ECs, augmented by hypoxia. IR activates a novel pathway stimulating EC migration directly through the expression of SDF-1 independent of HIF-1alpha induction. These observations might be exploited for stimulation of wound healing or controlling tumor angiogenesis
— id: 138185, year: 2010, vol: 116, page: 3669, stat: Journal Article,

Androgen receptor coactivator p44/Mep50 in breast cancer growth and invasion
Peng, Yi; Li, Yirong; Gellert, Lan Lin; Zou, Xuanyi; Wang, Jun; Singh, Baljit; Xu, Ruliang; Chiriboga, Luis; Daniels, Garrett; Pan, Ruimin; Zhang, David Y; Garabedian, Michael J; Schneider, Robert J; Wang, Zhengxin; Lee, Peng
2010 Dec;14(12):2780-2789, Journal of cellular & molecular medicine
Hormones and their receptors play an important role in the development and progression of breast carcinoma. Although the primary focus has been on oestrogen and oestrogen receptor (ER), androgen, androgen receptor (AR) and its coactivator(s) have been implicated in tumorigenesis of breast carcinoma and warrant further investigation. AR coactivator p44/Mep50 is identified as a subunit of methylosome complex and lately characterized as an AR coactivator that enhances AR mediated transcription activity in a ligand dependent manner. In prostate cancer, p44 is expressed in the nucleus of benign epithelia and translocated into the cytoplasm in cancer cells. Furthermore, nuclear expression of p44 inhibits prostate cancer growth. In this report, we examined the expression and function of p44 in breast cancer. In addition to being an AR coactivator, p44 also functions as an ER coactivator. In contrast to findings in prostate cancer, the expression of p44 shows strong cytoplasmic expression in morphologically normal terminal ductal lobular units, while nuclear p44 is observed in both ductal carcinoma in situ and invasive carcinoma. Further, overexpression of nuclear-localized p44 stimulates proliferation and invasion in MCF7 breast cancer cells in the presence of oestrogen and the process is ERalpha dependent. These findings strongly suggest that p44 plays a role in mediating the effects of hormones during tumorigenesis in breast
— id: 138376, year: 2010, vol: 14, page: 2780, stat: Journal Article,

Mitotic raptor promotes mTORC1 activity, G(2)/M cell cycle progression, and internal ribosome entry site-mediated mRNA translation
Ramirez-Valle, Francisco; Badura, Michelle L; Braunstein, Steve; Narasimhan, Manisha; Schneider, Robert J
2010 Jul;30(13):3151-3164, Molecular & cellular biology
The mTOR signaling complex integrates signals from growth factors and nutrient availability to control cell growth and proliferation, in part through effects on the protein-synthetic machinery. Protein synthesis rates fluctuate throughout the cell cycle but diminish significantly during the G(2)/M transition. The fate of the mTOR complex and its role in coordinating cell growth and proliferation signals with protein synthesis during mitosis remain unknown. Here we demonstrate that the mTOR complex 1 (mTORC1) pathway, which stimulates protein synthesis, is actually hyperactive during mitosis despite decreased protein synthesis and reduced activity of mTORC1 upstream activators. We describe previously unknown G(2)/M-specific phosphorylation of a component of mTORC1, the protein raptor, and demonstrate that mitotic raptor phosphorylation alters mTORC1 function during mitosis. Phosphopeptide mapping and mutational analysis demonstrate that mitotic phosphorylation of raptor facilitates cell cycle transit through G(2)/M. Phosphorylation-deficient mutants of raptor cause cells to delay in G(2)/M, whereas depletion of raptor causes cells to accumulate in G(1). We identify cyclin-dependent kinase 1 (cdk1 [cdc2]) and glycogen synthase kinase 3 (GSK3) pathways as two probable mitosis-regulated protein kinase pathways involved in mitosis-specific raptor phosphorylation and altered mTORC1 activity. In addition, mitotic raptor promotes translation by internal ribosome entry sites (IRES) on mRNA during mitosis and is demonstrated to be associated with rapamycin resistance. These data suggest that this pathway may play a role in increased IRES-dependent mRNA translation during mitosis and in rapamycin insensitivity
— id: 110095, year: 2010, vol: 30, page: 3151, stat: Journal Article,

AUF1 is involved in splenic follicular B cell maintenance
Sadri, Navid; Lu, Jin-Yu; Badura, Michelle L; Schneider, Robert J
2010 ;11:1-1, BMC Immunology
ABSTRACT: BACKGROUND: The adenosine/uridine-rich element (ARE)-binding protein AUF1 functions to regulate the inflammatory response through the targeted degradation of cytokine and other mRNAs that contain specific AREs in their 3' noncoding region (3' NCR). To investigate the role of AUF1 in the immune system, we characterized the lymphoid compartments of AUF1-deficient mice. RESULTS: Mice lacking AUF1 exhibit an altered proportion and size of splenic B cell subsets. We show prominent apoptosis in splenic B cell follicles and reduced expression of Bcl-2, A1, and Bcl-XL correlate with increased turnover and significant reduction in the number and proportion of splenic FO B cells in AUF1-deficient mice. In addition, AUF1-deficient mice exhibit a sharp decrease in splenic size and lymphocyte cellularity. Bone marrow transfer studies demonstrate that AUF1 deficiency induces cell-autonomous defects in mature B cell subsets but not in the overall number of splenocytes. Reconstitution of irradiated adult AUF1-deficient mice with wild-type bone marrow restores the proportion of FO and marginal zone (MZ) B cells, but does not rescue the decrease in the number of splenocytes. Functionally, AUF1-deficient mice mount an attenuated response to T cell-independent (TI) antigen, which correlates with impaired MZ B cell function. CONCLUSION: These data indicate that AUF1 is important in the maintenance of splenic FO B cells and adequate humoral immune responses
— id: 107373, year: 2010, vol: 11, page: 1, stat: Journal Article,

Translational control of breast cancer
Schneider R.J.
2010 ;24:?-?, FASEB journal
The role of translational control and changes in the protein synthetic machinery will be described that are associated with development of the most common form of advanced breast cancer, known as locally advanced breast cancer (advanced stage, large tumor size >5 cm, but non-metastatic). These alterations have been compared to the changes identified in the translation machinery of metastatic breast cancers and inflammatory breast cancers, the most lethal form of breast cancer that typically initiates as a non-solid tumor and rapidly metastasizes in a period of weeks. The alterations found in patient tumor specimens have been used to develop animal models that also recapitulate locally advanced and metastatic breast cancers, demonstrating the central role of translational control and alterations in the translation machinery in development and progression of human breast cancer. Studies have identified the overexpression of components of the Akt/mTOR/4E-BP1 pathway and overexpression of several translation initiation factors specific to LABC or IBC and their changes with metastatic progression of disease. These studies will also show the importance of specific translational control changes in human breast cancers that enable tumor angiogenesis (vascularization) and their ability to respond to hypoxia (oxygen deprivation), when tested in animal models
— id: 138404, year: 2010, vol: 24, page: ?, stat: Journal Article,

Five-year Results of Preoperative Paclitaxel with Concurrent Radiation Therapy in Locally Advanced Breast Cancer: Pathological Response Predicts for Survival
Schneider, R. J.; Formenti, S. C.; Chakravarthy, A.; Adams, S.; Spicer, D.; Lymberis, S.; Goldberg, J. D.; Pietenpol, J. A.
2010 OCT 13 ;78(3):S219-S219, International journal of radiation oncology biology physics
— id: 114016, year: 2010, vol: 78, page: S219, stat: Journal Article,

Translational control in cancer
Silvera, Deborah; Formenti, Silvia C; Schneider, Robert J
2010 Apr;10(4):254-266, Nature reviews. Cancer
Remarkable progress has been made in defining a new understanding of the role of mRNA translation and protein synthesis in human cancer. Translational control is a crucial component of cancer development and progression, directing both global control of protein synthesis and selective translation of specific mRNAs that promote tumour cell survival, angiogenesis, transformation, invasion and metastasis. Translational control of cancer is multifaceted, involving alterations in translation factor levels and activities unique to different types of cancers, disease stages and the tumour microenvironment. Several clinical efforts are underway to target specific components of the translation apparatus or unique mRNA translation elements for cancer therapeutics
— id: 115327, year: 2010, vol: 10, page: 254, stat: Journal Article,

High levels of Hsp90 cochaperone p23 promote tumor progression and poor prognosis in breast cancer by increasing lymph node metastases and drug resistance
Simpson, Natalie E; Lambert, W Marcus; Watkins, Renecia; Giashuddin, Shah; Huang, S Joseph; Oxelmark, Ellinor; Arju, Rezina; Hochman, Tsivia; Goldberg, Judith D; Schneider, Robert J; Reiz, Luiz Fernando Lima; Soares, Fernando Augusto; Logan, Susan K; Garabedian, Michael J
2010 Nov 1;70(21):8446-8456, Cancer research
p23 is a heat shock protein 90 (Hsp90) cochaperone located in both the cytoplasm and nucleus that stabilizes unliganded steroid receptors, controls the catalytic activity of certain kinases, regulates protein-DNA dynamics, and is upregulated in several cancers. We had previously shown that p23-overexpressing MCF-7 cells (MCF-7+p23) exhibit increased invasion without affecting the estrogen-dependent proliferative response, which suggests that p23 differentially regulates genes controlling processes linked to breast tumor metastasis. To gain a comprehensive view of the effects of p23 on estrogen receptor (ER)-dependent and -independent gene expression, we profiled mRNA expression from control versus MCF-7+p23 cells in the absence and presence of estrogen. A number of p23-sensitive target genes involved in metastasis and drug resistance were identified. Most striking is that many of these genes are also misregulated in invasive breast cancers, including PMP22, ABCC3, AGR2, Sox3, TM4SF1, and p8 (NUPR1). Upregulation of the ATP-dependent transporter ABCC3 by p23 conferred resistance to the chemotherapeutic agents etoposide and doxorubicin in MCF-7+p23 cells. MCF-7+p23 cells also displayed higher levels of activated Akt and an expanded phosphoproteome relative to control cells, suggesting that elevated p23 also enhances cytoplasmic signaling pathways. For breast cancer patients, tumor stage together with high cytoplasmic p23 expression more accurately predicted disease recurrence and mortality than did stage alone. High nuclear p23 was found to be associated with high cytoplasmic p23, therefore both may promote tumor progression and poor prognosis by increasing metastatic potential and drug resistance in breast cancer patients
— id: 114177, year: 2010, vol: 70, page: 8446, stat: Journal Article,

Cutaneous low-dose radiation increases tissue vascularity through upregulation of angiogenic and vasculogenic pathways
Thanik, Vishal D; Chang, Christopher C; Lerman, Oren Z; Greives, Matthew R; Le, Huong; Warren, Stephen M; Schneider, Robert J; Formenti, Sylvia C; Saadeh, Pierre B; Levine, Jamie P
2010 ;47(6):472-480, Journal of vascular research
BACKGROUND/AIMS: Neovascularization involves angiogenesis and vasculogenesis mediated by cytokines and soluble chemokines. The predominant stimulus is ischemia, however, recent data suggest that ionizing radiation (IR) has angiogenic potential. In this study we evaluated whether IR increases vascularity and perfusion in vivo. METHODS: In wild-type mice, a full-thickness, pedicled skin flap was created and isolated for localized irradiation at a dose of 5 Gy. Serial Doppler analysis of the flap was performed. The skin flaps were then harvested at various time points for vascularity and histologic analysis. Blood was concurrently harvested for serum and hematopoietic progenitor cell population analysis. RESULTS: IR to an ischemic flap augmented the angiogenic cytokines SDF-1 and VEGF. Serum MMP-9 and s-kit levels, which are critical for progenitor cell mobilization, were also increased. When hematopoietic progenitor cells were evaluated by Sca1+/Flk1+ cells, a correlate 2-fold increase was seen compared to controls. When the flaps were examined, both vascularity and perfusion were increased. CONCLUSION: In this study we demonstrate that local, low-dose IR upregulates angiogenic chemokines and results in progenitor cell mobilization to the systemic circulation. There is a resultant increase in the vascularity of the irradiated flap, suggesting that the pro-angiogenic effects of IR can be harnessed locally
— id: 113939, year: 2010, vol: 47, page: 472, stat: Journal Article,

Regulation of protein synthesis by ionizing radiation
Braunstein, Steve; Badura, Michelle L; Xi, Qiaoran; Formenti, Silvia C; Schneider, Robert J
2009 Nov;29(21):5645-5656, Molecular & cellular biology
Ionizing radiation (IR) is a physiologically important stress to which cells respond by the activation of multiple signaling pathways. Using a panel of immortalized and transformed breast epithelial cell lines, we demonstrate that IR regulation of protein synthesis occurs in nontransformed cells and is lost with transformation. In nontransformed cells, IR rapidly activates the MAP kinases ERK1/2, resulting in an early transient increase in cap-dependent mRNA translation that involves mTOR and is radioprotective, enhancing the translation of a subset of mRNAs encoding proteins involved in DNA repair and cell survival. Following a transient increase in translation, IR-sensitive (nontransformed) cells inhibit cap-dependent protein synthesis through a mechanism that involves activation of p53, induction of Sestrin 1 and 2 genes, and stimulation of AMP kinase, inhibiting mTOR and hypophosphorylating 4E-BP1. IR is shown to block proteasome-mediated decay of 4E-BP1, increasing its abundance and the sequestration of eIF4E. The IR signal that impairs mTOR-dependent protein synthesis at late times is assembly of the DNA damage response machinery, consisting of Mre11, Rad50, and NBS1 (MRN); activation of the MRN complex kinase ATM; and p53. These results link genotoxic signaling from the DNA damage response complex to the control of protein synthesis
— id: 104346, year: 2009, vol: 29, page: 5645, stat: Journal Article,

Dose-dependent effect of radiation on angiogenic and angiostatic CXC chemokine expression in human endothelial cells
Chang, Christopher C; Lerman, Oren Z; Thanik, Vishal D; Scharf, Carrie L; Greives, Matthew R; Schneider, Robert J; Formenti, Sylvia C; Saadeh, Pierre B; Warren, Stephen M; Levine, Jamie P
2009 Dec;48(3):295-302, Cytokine
Blood vessel growth is regulated by angiogenic and angiostatic CXC chemokines, and radiation is a vasculogenic stimulus. We investigated the effect of radiation on endothelial cell chemokine signaling, receptor expression, and migration and apoptosis. Human umbilical vein endothelial cells were exposed to a single fraction of 0, 5, or 20Gy of ionizing radiation (IR). All vasculogenic chemokines (CXCL1-3/5-8) increased 3-13-fold after 5 or 20Gy IR. 20Gy induced a marked increase (1.6-4-fold) in angiostatic CXC chemokines. CXCR4 expression increased 3.5 and 7-fold at 48h after 5 and 20Gy, respectively. Bone marrow progenitor cell chemotaxis was augmented by conditioned media from cells treated with 5Gy IR. Whereas 5Gy markedly decreased intrinsic cell apoptosis (0Gy=16%+/-3.6 vs. 5Gy=4.5%+/-0.3), 20Gy increased it (21.4%+/-1.2); a reflection of pro-survival angiogenic chemokine expression. Radiation induces a dose-dependent increase in pro-angiogenic CXC chemokines and CXCR4. In contrast, angiostatic chemokines and apoptosis were induced at higher (20Gy) radiation doses. Cell migration improved significantly following 5Gy, but not 20Gy IR. Collectively, these data suggest that lower doses of IR induce an angiogenic cascade while higher doses produce an angiostatic profile
— id: 104228, year: 2009, vol: 48, page: 295, stat: Journal Article,

The regulation of protein synthesis in cancer
Cuesta, Rafael; Gupta, Malavika; Schneider, Robert J
2009 ;90:255-292, Progress in molecular biology & translational science
Translational control of cancer is a multifaceted process, involving alterations in translation factor levels and activities that are unique to the different types of cancers and the different stages of disease. Translational alterations in cancer include adaptations of the tumor itself, of the tumor microenvironment, an integral component in disease, and adaptations that occur as cancer progresses from development to local disease and ultimately to metastatic disease. Adaptations include the overexpression and increased activity of specific translation factors, the physical or functional loss of translation regulatory components, increased production of ribosomes, selective mRNA translation, and alteration of signal transduction pathways to permit unfettered activation of protein synthesis. There is intense clinical interest to capitalize on the emerging new understanding of translational control in cancer by targeting specific components of the translation apparatus that are altered in disease for the development of specific cancer therapeutics. Clinical trial data are nascent but encouraging, suggesting that translational control constitutes an important new area for drug development in human cancer
— id: 132875, year: 2009, vol: 90, page: 255, stat: Journal Article,

Similar regulation of human inducible nitric-oxide synthase expression by different isoforms of the RNA-binding protein AUF1
Pautz, Andrea; Linker, Katrin; Altenhofer, Sebastian; Heil, Sebastian; Schmidt, Nadine; Art, Julia; Knauer, Shirley; Stauber, Roland; Sadri, Navid; Pont, Adam; Schneider, Robert J; Kleinert, Hartmut
2009 Jan 30;284(5):2755-2766, Journal of biological chemistry
The ARE/poly-(U) binding factor 1 (AUF1), a protein family consisting of four isoforms, is believed to mediate mRNA degradation by binding to AU-rich elements (ARE). However, evidence exists that individual AUF1 isoforms may stabilize ARE-containing mRNAs. The 3'-untranslated region of the human inducible nitric-oxide synthase (iNOS) contains five AREs, which promote RNA degradation. We have recently shown that the RNA-binding protein KSRP is critically involved in the decay of the iNOS mRNA. In this study we examined the effects of the individual AUF1 isoforms on iNOS expression. Overexpression of each AUF1 isoform reduces iNOS expression on mRNA and protein levels to the same extent by modulation of mRNA stability. Accordingly, knockdown of all or individual AUF1 isoforms by an RNA interference approach enhances iNOS expression. The AUF1 effect on iNOS expression is dependent on the iNOS 3'-untranslated region sequence, as demonstrated in transfection experiments with a reporter mRNA. Binding studies showed that all AUF1 isoforms interact with the same AU-rich region in the iNOS-3'-untranslated region. Cytokine stimulation altered intracellular AUF1 binding activities. These data demonstrate that AUF1 is an important factor that promotes iNOS mRNA degradation. Furthermore, all individual AUF1 isoforms act in a similar manner
— id: 94643, year: 2009, vol: 284, page: 2755, stat: Journal Article,

Auf1/Hnrnpd-deficient mice develop pruritic inflammatory skin disease
Sadri, Navid; Schneider, Robert J
2009 Mar;129(3):657-670, Journal of investigative dermatology
Mice lacking heterogenous nuclear ribonuclear protein D (Hnrnpd), also known as Auf1, a regulator of inflammatory cytokine mRNA stability, develop chronic dermatitis with age that is characterized by pruritus and excoriations. Histological analysis showed marked epidermal acanthosis and spongiosis, neovascularization, and elevated number of inflammatory cells, including T cells, macrophages, neutrophils, mast cells, and eosinophils. Hnrnpd-deficient (Hnrnpd(tm1Rjsc)) mice with dermatitis display elevated serum IgE levels. Lesions in Hnrnpd(tm1Rjsc) mice were associated with a shift towards a Th(2) immune environment. Evaluation of T-cell-mediated skin inflammation by assaying contact hypersensitivity indicated an increased response in Hnrnpd(tm1Rjsc) mice. T cells and macrophages from Hnrnpd(tm1Rjsc) mice demonstrate a number of abnormalities associated with dermatitis, including increased IL2, tumor-necrosis factor-alpha (TNFalpha), and IL1beta production. Finally, many features of spontaneous dermatitis could be recapitulated in experimentally induced lesions by subcutaneous injection of CCL27 and TNF in unaffected Hnrnpd(tm1Rjsc) mice. Collectively, these data highlight the importance of HNRNPD and proper regulation of mRNA stability in the intricate processes of leukocyte recruitment and inflammatory activation within the skin
— id: 94644, year: 2009, vol: 129, page: 657, stat: Journal Article,

Essential role for eIF4GI overexpression in the pathogenesis of inflammatory breast cancer
Silvera, Deborah; Arju, Rezina; Darvishian, Farbod; Levine, Paul H; Zolfaghari, Ladan; Goldberg, Judith; Hochman, Tsivia; Formenti, Silvia C; Schneider, Robert J
2009 Jul;11(7):903-908, Nature cell biology
Inflammatory breast cancer (IBC) is the most lethal form of primary breast cancer. IBC lethality derives from generation of tumour emboli, which are non-adherent cell clusters that rapidly spread by a form of continuous invasion known as passive metastasis. In most cancers, expression of E-cadherin, an epithelial marker, is indicative of low metastatic potential. In IBC, E-cadherin is overexpressed and supports formation of tumour emboli by promoting tumour cell interactions rather than adherence to stroma. E-cadherin, a surface component of adherens junctions, is anchored by interaction with p120 catenin (p120). We show that the unique pathogenic properties of IBC result in part from overexpression of the translation initiation factor eIF4GI in most IBCs. eIF4GI reprograms the protein synthetic machinery for increased translation of mRNAs with internal ribosome entry sites (IRESs) that promote IBC tumour cell survival and formation of tumour emboli. Overexpression of eIF4GI promotes formation of IBC tumour emboli by enhancing translation of IRES-containing p120 mRNAs. These findings provide a new understanding of translational control in the development of advanced breast cancer
— id: 100610, year: 2009, vol: 11, page: 903, stat: Journal Article,

Inflammatory breast cancer cells are constitutively adapted to hypoxia
Silvera, Deborah; Schneider, Robert J
2009 Oct 1;8(19):3091-3096, Cell cycle
We recently showed that overexpression of translation initiation factor eIF4G partially drives the unusual pathological features of Inflammatory Breast Cancer (IBC), the most lethal form of primary breast cancer. IBC has the peculiar feature that, rather than develop as a solid tumor, it typically generates rapidly metastasizing tight clusters of cancer cells referred to as tumor cell emboli, consisting of cancer cells held together by increased membrane expression of E-cadherin. Overexpression of eIF4GI in IBC leads to a specific increase in the translation of internal ribosomal entry site (IRES) containing mRNAs, of which two encode key proteins involved in the pathological features of IBC. One of these mRNAs encodes p120 catenin, which mediates E-cadherin retention at the cell surface, and the other encodes VEGF, which accounts for high levels of IBC angiogenesis and resistance to hypoxia. Here we show that IBC cells have adapted to the persistent hypoxia they experience as tumor emboli, by reprogramming the protein synthesis machinery to constitutively translate mRNAs required for IBC cell survival during hypoxia, even under normal oxygen (normoxic) conditions. Thus, IBC cells have been able to behave as if they are continuously hypoxic even when they are not
— id: 104721, year: 2009, vol: 8, page: 3091, stat: Journal Article,

Acquisition of stable inducible up-regulation of nuclear factor-kappaB by tumor necrosis factor exposure confers increased radiation resistance without increased transformation in breast cancer cells
Braunstein, Steve; Formenti, Silvia C; Schneider, Robert J
2008 Jan;6(1):78-88, Molecular cancer research
High-grade breast cancers are better adapted to hypoxia and more resistant to chemotherapy and radiotherapy. Constitutive activation of the transcription factor nuclear factor-kappaB (NF-kappaB) increases in breast tumors and in breast cancer cell lines, where it promotes chemoradiation resistance, in part by activation of antiapoptotic genes. The role for up-regulation of NF-kappaB in breast cancer progression is less clear. Here, we first show that whereas the constitutive activity of NF-kappaB is incrementally elevated from immortalized breast epithelial to frank transformed invasive ductal breast cancer cell lines (~3-fold, +/-0.1-fold, P < 0.05), inflammatory cytokine-inducible activity is further increased (up to 9-fold, +/-0.9-fold, P < 0.05). We then show that inhibition of NF-kappaB activity selectively sensitizes transformed but not immortalized cells to killing by ionizing radiation or low levels of tumor necrosis factor (TNF) by up to 10-fold (+/-1-fold, P < 0.05) but has little effect on hypoxia-mediated cell death. Prolonged cultivation of immortalized and partially transformed cells in TNF selected for cells displaying stable constitutive and strongly inducible overexpression of NF-kappaB even in the absence of TNF. Stable acquisition of increased NF-kappaB activity conferred resistance to ionizing radiation or inflammatory cytokines, which was dependent on elevated NF-kappaB activity, but had no effect on transformation potential measured by in vitro and in vivo parameters. Thus, TNF and possibly other inflammatory cytokines in the tumor-stroma matrix likely select for breast cancer cells that stably overexpress NF-kappaB, leading to greater cancer cell survival. Greater cell survival despite increased genomic injury may permit increased acquisition of malignant genetic alterations as well as resistance to chemoradiation therapy
— id: 76463, year: 2008, vol: 6, page: 78, stat: Journal Article,

Glioma-like proliferation within tissues excised as tubers in patients with tuberous sclerosis complex
Fischer, Ingeborg; Cunliffe, Clare; Bollo, Robert J; Weiner, Howard L; Devinsky, Orrin; Ruiz-Tachiquin, Martha-Eugenia; Venuto, Toni; Pearlman, Alexander; Chiriboga, Luis; Schneider, Robert J; Ostrer, Harry; Miller, Douglas C
2008 Jul;116(1):67-77, Acta neuropathologica
We describe diffuse glioma-like infiltrates in excised tubers in five out of forty Tuberous sclerosis complex (TSC) patients undergoing excision of a tuber at our institution within the last 10 years. All patients presented with refractory seizures. Resection specimens from four patients had the pathognomonic histologic features of neuroglial hamartomas (tubers) and in one case there was cortical microdysgenesis lacking cells typical of TSC. All lesions were associated with an infiltrate of atypical, mostly elongate, glioma-like small cells, which were immunoreactive for GFAP in three, and pS6 (a marker for activity of the mTOR pathway), in two cases. MAP-2 and CD34, were negative and MIB-1 (Ki67) immunostains ranged from <1-21%. Array-based comparative genomic hybridization revealed that these proliferative phenomena were associated with 21 different copy number aberrations in comparison with a tuber without atypical infiltrates. Postoperatively (follow-up period ranging from 8 to 34 months) none of the patients have any evidence of a glioma. We report that tubers resected for treatment of seizures are sometimes associated with glioma-like lesions, which are indistinguishable from infiltrating gliomas by morphology and immunohistochemistry. Genomic analysis with SNP arrays revealed copy number changes which may be associated with the pathogenesis of such infiltrates
— id: 79446, year: 2008, vol: 116, page: 67, stat: Journal Article,

Members of the NuRD chromatin remodeling complex interact with AUF1 in developing cortical neurons
Lee, Cheol; Gyorgy, Andrea; Maric, Dragan; Sadri, Navid; Schneider, Robert J; Barker, Jeffery L; Lawson, Michael; Agoston, Denes V
2008 Dec;18(12):2909-2919, Cerebral cortex
Chromatin remodeling plays an important role in coordinating gene expression during cortical development, however the identity of molecular complexes present in differentiating cortical neurons that mediate the process remains poorly understood. The A + U-rich element-binding factor 1 (AUF1) is a known regulator of messenger RNA stability and also acts as a transcription factor upon binding to AT-rich DNA elements. Here we show that AUF1 is specifically expressed in subsets of proliferating neural precursors and differentiating postmitotic neurons of the developing cerebral cortex. Moreover, AUF1 is coexpressed with histone deacetylase 1 (HDAC1) and metastasis-associated protein 2 (MTA2), members of the nucleosome remodeling and histone deacetylase complex. AUF1 specifically and simultaneously binds to HDAC1, MTA2, and AT-rich DNA element, its gene regulatory function is modulated by the extent of histone acetylation and in animals lacking AUF1, the composition of the complex is modified. These results suggest that AUF1 is involved in integrating genetic and epigenetic signals during cortical development through recruiting HDAC1 and MTA2 to AT-rich DNA elements
— id: 94645, year: 2008, vol: 18, page: 2909, stat: Journal Article,

Radiation-induced CXCL16 release by breast cancer cells attracts effector T cells
Matsumura, Satoko; Wang, Baomei; Kawashima, Noriko; Braunstein, Steve; Badura, Michelle; Cameron, Thomas O; Babb, James S; Schneider, Robert J; Formenti, Silvia C; Dustin, Michael L; Demaria, Sandra
2008 Sep 1;181(5):3099-3107, Journal of immunology
Recruitment of effector T cells to inflamed peripheral tissues is regulated by chemokines and their receptors, but the factors regulating recruitment to tumors remain largely undefined. Ionizing radiation (IR) therapy is a common treatment modality for breast and other cancers. Used as a cytocidal agent for proliferating cancer cells, IR in combination with immunotherapy has been shown to promote immune-mediated tumor destruction in preclinical studies. In this study we demonstrate that IR markedly enhanced the secretion by mouse and human breast cancer cells of CXCL16, a chemokine that binds to CXCR6 on Th1 and activated CD8 effector T cells, and plays an important role in their recruitment to sites of inflammation. Using a poorly immunogenic mouse model of breast cancer, we found that irradiation increased the migration of CD8(+)CXCR6(+) activated T cells to tumors in vitro and in vivo. CXCR6-deficient mice showed reduced infiltration of tumors by activated CD8 T cells and impaired tumor regression following treatment with local IR to the tumor and Abs blocking the negative regulator of T cell activation, CTLA-4. These results provide the first evidence that IR can induce the secretion by cancer cells of proinflammatory chemotactic factors that recruit antitumor effector T cells. The ability of IR to convert tumors into 'inflamed' peripheral tissues could be exploited to overcome obstacles at the effector phase of the antitumor immune response and improve the therapeutic efficacy of immunotherapy
— id: 81352, year: 2008, vol: 181, page: 3099, stat: Journal Article,

eIF4GI links nutrient sensing by mTOR to cell proliferation and inhibition of autophagy
Ramirez-Valle, Francisco; Braunstein, Steve; Zavadil, Jiri; Formenti, Silvia C; Schneider, Robert J
2008 Apr 21;181(2):293-307, Journal of cell biology
Translation initiation factors have complex functions in cells that are not yet understood. We show that depletion of initiation factor eIF4GI only modestly reduces overall protein synthesis in cells, but phenocopies nutrient starvation or inhibition of protein kinase mTOR, a key nutrient sensor. eIF4GI depletion impairs cell proliferation, bioenergetics, and mitochondrial activity, thereby promoting autophagy. Translation of mRNAs involved in cell growth, proliferation, and bioenergetics were selectively inhibited by reduction of eIF4GI, as was the mRNA encoding Skp2 that inhibits p27, whereas catabolic pathway factors were increased. Depletion or overexpression of other eIF4G family members did not recapitulate these results. The majority of mRNAs that were translationally impaired with eIF4GI depletion were excluded from polyribosomes due to the presence of multiple upstream open reading frames and low mRNA abundance. These results suggest that the high levels of eIF4GI observed in many breast cancers might act to specifically increase proliferation, prevent autophagy, and release tumor cells from control by nutrient sensing
— id: 79095, year: 2008, vol: 181, page: 293, stat: Journal Article,

Lsm proteins bind and stabilize RNAs containing 5' poly(A) tracts
Bergman, Naomi; Moraes, Karen C M; Anderson, John R; Zaric, Bozidarka; Kambach, Christian; Schneider, Robert J; Wilusz, Carol J; Wilusz, Jeffrey
2007 Sep;14(9):824-831, Nature structural & molecular biology
Many orthopoxvirus messenger RNAs have an unusual nontemplated poly(A) tract of 5 to 40 residues at the 5' end. The precise function of this feature is unknown. Here we show that 5' poly(A) tracts are able to repress RNA decay by inhibiting 3'-to-5' exonucleases as well as decapping of RNA substrates. UV cross-linking analysis demonstrated that the Lsm complex associates with the 5' poly(A) tract. Furthermore, recombinant Lsm1-7 complex specifically binds 5' poly(A) tracts 10 to 21 nucleotides in length, consistent with the length of 5' poly(A) required for stabilization. Knockdown of Lsm1 abrogates RNA stabilization by the 5' poly(A) tract. We propose that the Lsm complex simultaneously binds the 3' and 5' ends of these unusual messenger RNAs and thereby prevents 3'-to-5' decay. The implications of this phenomenon for cellular mRNA decay are discussed
— id: 94646, year: 2007, vol: 14, page: 824, stat: Journal Article,

A hypoxia-controlled cap-dependent to cap-independent translation switch in breast cancer
Braunstein, Steve; Karpisheva, Ksenia; Pola, Carolina; Goldberg, Judith; Hochman, Tsivia; Yee, Herman; Cangiarella, Joan; Arju, Rezina; Formenti, Silvia C; Schneider, Robert J
2007 Nov 9;28(3):501-512, Molecular cell
Translational regulation is critical in cancer development and progression. Translation sustains tumor growth and development of a tumor vasculature, a process known as angiogenesis, which is activated by hypoxia. Here we first demonstrate that a majority of large advanced breast cancers overexpress translation regulatory protein 4E-BP1 and initiation factor eIF4G. Using model animal and cell studies, we then show that overexpressed 4E-BP1 and eIF4G orchestrate a hypoxia-activated switch from cap-dependent to cap-independent mRNA translation that promotes increased tumor angiogenesis and growth at the level of selective mRNA translation. Elevated levels of 4E-BP1 trigger hypoxia inhibition of cap-dependent mRNA translation at high-oxygen levels and, with eIF4G, increase selective translation of mRNAs containing internal ribosome entry sites (IRESs) that include key proangiogenic, hypoxia, and survival mRNAs. The switch from cap-dependent to cap-independent mRNA translation facilitates tumor angiogenesis and hypoxia responses in animal models
— id: 75671, year: 2007, vol: 28, page: 501, stat: Journal Article,

Exploiting breast cancer cells stress response to ionizing radiation to improve the effectiveness of immunotherapy
Demaria, S; Wang, B; Badura, M; Matsumura, S; Kawashima, N; Cameron, T; Dustin, M; Schneider, RJ; Formenti, SC
2007 JAN ;69(3):S597-S597, International journal of radiation oncology biology physics
— id: 87199, year: 2007, vol: 69, page: S597, stat: Journal Article,

Single-dose radiation stimulates induction of stromal derived factor-1 expression and endothelial cell migration independently of hypoxia activation
Lerman, O; Grieves, M; Levine, J; Schneider, R; Formenti, S
2007 JAN ;69(3):S592-S593, International journal of radiation oncology biology physics
— id: 87197, year: 2007, vol: 69, page: S592, stat: Journal Article,

Vitronectin in the tumor microenvironment promotes breast cancer cell proliferation and elevated protein synthesis despite hypoxia by integrin alpha v beta 3 activation of the mTOR/4E-BP1 pathway
Pola, C; Formenti, SC; Schneider, RJ
2007 DEC ;106(1):S162-S162, Breast cancer research & treatment
— id: 75804, year: 2007, vol: 106, page: S162, stat: Journal Article,

TNF Activates a Conserved Innate Antiviral Response to HBV that Destabilizes Nucleocapsids and Reduces Nuclear Viral DNA
Puro, Robyn; Schneider, Robert J
2007 Jul;81(14):7351-7362, Journal of virology
Tumor Necrosis Factor (TNF) is critical for the control of hepatitis B virus (HBV) in the clinical setting and in model systems. TNF induces noncytopathic suppression and clearance of HBV in animal models possibly through reduction of viral nucleocapsids, but the mechanism is not well described. Here, we demonstrate the molecular mechanism and broad host range for TNF action against HBV. We show that TNF rapidly blocks HBV replication by promoting destabilization of preexisting cytoplasmic viral nucleocapsids containing viral RNA and DNA, as well as empty nucleocapsids. TNF destabilized human HBV nucleocapsids in a variety of human hepatocytic cell lines and in primary rat hepatocytes, as well as Duck hepatitis B Virus (DHBV) nucleocapsids in chicken hepatocytic cells. Lysates from TNF-treated uninfected cells also destabilized HBV nucleocapsids in vitro. Moreover, inhibition of DHBV DNA replication by TNF blocks nuclear accumulation of the viral transcription template, maintenance of which is essential for establishment and maintenance of chronic infection. We show that TNF destabilization of HBV nucleocapsids does not involve ubiquitination or methylation of the viral core protein, and is not mediated by the nitric oxide-free radical arm of the TNF pathway. These results define a novel anti-viral mechanism mediated by TNF against multiple types of HBVs in different species
— id: 72042, year: 2007, vol: 81, page: 7351, stat: Journal Article,

Elevated levels of translation initiation factor eIF4G suppresses Radiation(IR)-induced autophagy and cell death
Schneider, RJ; Braunstein, S; Badura, M; Formenti, SC
2007 JAN ;69(3):S593-S593, International journal of radiation oncology biology physics
— id: 87198, year: 2007, vol: 69, page: S593, stat: Journal Article,

Inflammatory breast cancer pathogenesis is mediated in significant part by translation initiation factor eIF4G amplification and unorthodox protein synthesis
Silvera, D; Arju, R; Darvishian, F; Levine, PH; Formenli, SC; Schneider, RJ
2007 DEC ;106(1):S18-S18, Breast cancer research & treatment
— id: 75798, year: 2007, vol: 106, page: S18, stat: Journal Article,

Radiotherapy treatment of early-stage prostate cancer with IMRT and protons: a treatment planning comparison
Trofimov, Alexei; Nguyen, Paul L; Coen, John J; Doppke, Karen P; Schneider, Robert J; Adams, Judith A; Bortfeld, Thomas R; Zietman, Anthony L; Delaney, Thomas F; Shipley, William U
2007 Oct 1;69(2):444-453, International journal of radiation oncology biology physics
PURPOSE: To compare intensity-modulated photon radiotherapy (IMRT) with three-dimensional conformal proton therapy (3D-CPT) for early-stage prostate cancer, and explore the potential utility of intensity-modulated proton therapy (IMPT). METHODS AND MATERIALS: Ten patients were planned with both 3D-CPT (two parallel-opposed lateral fields) and IMRT (seven equally spaced coplanar fields). Prescribed dose was 79.2 Gy (or cobalt Gray-equivalent, [CGE] for protons) to the prostate gland. Dose-volume histograms, dose conformity, and equivalent uniform dose (EUD) were compared. Additionally, plans were optimized for 3D-CPT with nonstandard beam configuration, and for IMPT assuming delivery with beam scanning. RESULTS: At least 98% of the planning target volume received the prescription dose. IMRT plans yielded better dose conformity to the target, whereas proton plans achieved higher dose homogeneity and better sparing of rectum and bladder in the range below 30 Gy/CGE. Bladder volumes receiving more than 70 Gy/CGE (V70) were reduced, on average, by 34% with IMRT vs. 3D-CPT, whereas rectal V70 were equivalent. EUD from 3D-CPT and IMRT plans were indistinguishable within uncertainties for both bladder and rectum. With the use of small-angle lateral-oblique fields in 3D-CPT and IMPT, the rectal V70 was reduced by up to 35% compared with the standard lateral configuration, whereas the bladder V70 increased by less than 10%. CONCLUSIONS: In the range higher than 60 Gy/CGE, IMRT achieved significantly better sparing of the bladder, whereas rectal sparing was similar with 3D-CPT and IMRT. Dose to healthy tissues in the range lower than 50% of the target prescription was substantially lower with proton therapy
— id: 94647, year: 2007, vol: 69, page: 444, stat: Journal Article,

Transforming growth factor-beta and microRNA:mRNA regulatory networks in epithelial plasticity
Zavadil, Jiri; Narasimhan, Manisha; Blumenberg, Miroslav; Schneider, Robert J
2007 ;185(1-3):157-161, Cells tissues organs
Noncoding microRNAs act as posttranscriptional repressors of gene function and are often deregulated in cancers and other diseases. Here we review recent findings on microRNA roles in tumorigenesis and report a microRNA profiling screen in transforming growth factor-beta1 (TGF-beta)-induced epithelial-mesenchymal transition (EMT) in human keratinocytes, a model of epithelial cell plasticity underlying epidermal injury and skin carcinogenesis. We describe a novel EMT-specific microRNA signature that includes induction of miR-21, a candidate oncogenic microRNA associated with carcinogenesis. By integrating the microRNA screen results with target prediction algorithms and gene expression profiling data, we outline a framework for TGF-beta-directed microRNA:messenger RNA (mRNA) regulatory circuitry and discuss its biological relevance for tumor progression.
— id: 73003, year: 2007, vol: 185, page: 157, stat: Journal Article,

Activation of focal adhesion kinase by hepatitis B virus HBx protein: multiple functions in viral replication
Bouchard, Michael J; Wang, Lihua; Schneider, Robert J
2006 May;80(9):4406-4414, Journal of virology
The hepatitis B virus (HBV) X protein (HBx) is a multifunctional regulator of cellular signal transduction and transcription pathways and has a critical role in HBV replication. Much of the cytoplasmic signal transduction activity associated with HBx expression and its stimulation of viral replication is attributable to HBx-induced activation of calcium signaling pathways involving Pyk2 and Src tyrosine kinases. To further characterize upstream signal transduction pathways that are required for HBx activity, including activation of Src and mitogen-activated protein kinase (MAPK) cascades, we determined whether focal adhesion kinase (FAK), a known regulator of Src family kinases and the other member of the Pyk2/FAK kinase family, is activated by HBx. We report that HBx activates FAK and that FAK activation is important for multiple HBx functions. Dominant inhibiting forms of FAK blocked HBx activation of Src kinases and downstream signal transduction, HBx stimulation of NF-kappaB and AP-1-dependent transcription, and HBV DNA replication. We also demonstrate that HBx-induced activation of FAK is dependent on cellular calcium signaling, which is modulated by HBx. Moreover, prolonged expression of HBx increases both FAK activity and its level of expression. FAK activation may play a role in cellular transformation and cancer progression. HBx stimulation of FAK activity and abundance may also be relevant as a potential cofactor in HBV-associated hepatocellular carcinoma
— id: 72045, year: 2006, vol: 80, page: 4406, stat: Journal Article,

Ionizing radiation regulates protein synthesis through two novel ATM-independent and ATM-dependent pathways involving mTOR and translation regulator, 4E-BP1
Braunstein, S; Badura, M; Xi, Q; Formenti, SC; Schneider, RJ
2006 FEB ;66(3):S71-S71, International journal of radiation oncology biology physics
— id: 70752, year: 2006, vol: 66, page: S71, stat: Journal Article,

Inhibition of Cap-initiation complexes linked to a novel mechanism of eIF4G depletion in acute myocardial ischemia
Connolly, E P; Thuillier, V; Rouy, D; Bouetard, G; Schneider, R J
2006 Sep;13(9):1586-1594, Cell death & differentiation
Translational control in the rat heart was characterized during acute myocardial ischemia introduced by left coronary artery ligature. Within 10 min of ischemia, eukaryotic (eIF)4E binds to its negative regulator, eIF4E-binding protein-1 (4E-BP1), but the levels of 4E-BP1 are insufficient to disrupt cap-dependent mRNA initiation complexes. However, by 1 h of ischemia, the abundance of the cap-initiation complex protein eIF4G is reduced by relocalization into TIAR protein complexes, triggering 4E-BP1 sequestration of eIF4E and disruption of cap-dependent mRNA initiation complexes. As the heart begins to fail at 6 h, proteolysis of eIF4G is observed, resulting in its depletion and accompanied by limited destruction of 4E-BP1 and eIF4E. eIF4G proteolysis and modest loss of 4E-BP1 are associated with caspase-3 activation and induction of cardiomyocyte apoptotic and necrotic death. Acute heart ischemia therefore downregulates cap-dependent translation through eIF4E sequestration triggered by eIF4G depletion
— id: 72046, year: 2006, vol: 13, page: 1586, stat: Journal Article,

Hypoxia inhibits protein synthesis through a 4E-BP1 and elongation factor 2 kinase pathway controlled by mTOR and uncoupled in breast cancer cells
Connolly, Eileen; Braunstein, Steve; Formenti, Silvia; Schneider, Robert J
2006 May;26(10):3955-3965, Molecular & cellular biology
Hypoxia is a state of low oxygen availability that limits tumor growth. The mechanism of protein synthesis inhibition by hypoxia and its circumvention by transformation are not well understood. Hypoxic breast epithelial cells are shown to downregulate protein synthesis by inhibition of the kinase mTOR, which suppresses mRNA translation through a novel mechanism mitigated in transformed cells: disruption of proteasome-targeted degradation of eukaryotic elongation factor 2 (eEF2) kinase and activation of the regulatory protein 4E-BP1. In transformed breast epithelial cells under hypoxia, the mTOR and S6 kinases are constitutively activated and the mTOR negative regulator tuberous sclerosis complex 2 (TSC2) protein fails to function. Gene silencing of 4E-BP1 and eEF2 kinase or TSC2 confers resistance to hypoxia inhibition of protein synthesis in immortalized breast epithelial cells. Breast cancer cells therefore acquire resistance to hypoxia by uncoupling oxygen-responsive signaling pathways from mTOR function, eliminating inhibition of protein synthesis mediated by 4E-BP1 and eEF2
— id: 64480, year: 2006, vol: 26, page: 3955, stat: Journal Article,

14-3-3sigma is a p37 AUF1-binding protein that facilitates AUF1 transport and AU-rich mRNA decay
He, Cheng; Schneider, Robert
2006 Aug 23;25(16):3823-3831, EMBO journal
Short-lived cytokine mRNAs contain an AU-rich destabilizing element (ARE). AUF1 proteins bind the ARE, undergo shuttling, and promote cytoplasmic ARE-mRNA decay through a poorly understood mechanism. We therefore identified AUF1-interacting proteins that may play a role in ARE-mRNA decay. We used mass-spectrometry to identify 14-3-3sigma protein as an AUF1-interacting protein. 14-3-3sigma binds selectively and strongly to p37 AUF1 and to a lesser extent to the p40 isoform, the two isoforms most strongly associated with ARE-mRNA decay, but not to the two larger isoforms, p42 and p45. The 14-3-3sigma interaction site on p37 was mapped to a region found only in the two smaller AUF1 isoforms and which overlaps a putative nuclear localization signal (NLS). Stable overexpression of 14-3-3sigma significantly increased cytoplasmic accumulation of p37 AUF1 and reduced the steady-state level and half-life of a reporter ARE-mRNA. siRNA silencing of AUF1 eliminated the effect of 14-3-3sigma overexpression. 14-3-3sigma therefore binds to p37 AUF1, retains it in the cytoplasm probably by masking its NLS, and enhances rapid turnover of ARE-mRNAs
— id: 68985, year: 2006, vol: 25, page: 3823, stat: Journal Article,

A translationally controlled angiogenic switch in locally advanced breast cancer
Karpisheva, K; Braunstein, S; Goldberg, J; Singh, B; Pola, C; Formenti, SC; Schneider, RJ
2006 FEB ;100(2):S11-S11, Breast cancer research & treatment
— id: 71005, year: 2006, vol: 100, page: S11, stat: Journal Article,

MTOR/4E-BP1 pathway is a translational regulator of prostate cancer progression
Karpisheva, KV; Xi, QR; Braunstein, S; Melamed, J; Goldberg, J; Schneider, R
2006 MAR 6 ;20(4):A109-A109, FASEB journal
— id: 63857, year: 2006, vol: 20, page: A109, stat: Journal Article,

Assembly of AUF1 with eIF4G-poly(A) binding protein complex suggests a translation function in AU-rich mRNA decay
Lu, Jin-Yu; Bergman, Naomi; Sadri, Navid; Schneider, Robert J
2006 May;12(5):883-893, RNA
An AU-rich element (ARE) located in the 3'-untranslated region of many short-lived mRNAs functions as an instability determinant for these transcripts. AUF1/hnRNP D, an ARE-binding protein family consisting of four isoforms, promotes rapid decay of ARE-mRNAs. The mechanism by which AUF1 promotes rapid decay of ARE-mRNA is unclear. AUF1 has been shown to form an RNase-resistant complex in cells with the cap-initiation complex and heat shock proteins Hsp70 and Hsc70, as well as other unidentified factors. To understand the function of the AUF1 complex, we have biochemically investigated the association of AUF1 with the components of the translation initiation complex. We used purified recombinant proteins and a synthetic ARE RNA oligonucleotide to determine the hierarchy of protein interactions in vitro and the effect of AUF1 binding to the ARE on the formation of protein complexes. We demonstrate that all four AUF1 protein isoforms bind directly and strongly to initiation factor eIF4G at a C-terminal site regardless of AUF1 interaction with the ARE. AUF1 is shown to directly interact with poly(A) binding protein (PABP), both independently of eIF4G and in a complex with eIF4G. AUF1-PABP interaction is opposed by AUF1 binding to the ARE or Hsp70 heat shock protein. In vivo, AUF1 interaction with PABP does not alter PABP stability. Based on these and other data, we propose a model for the molecular interactions of AUF1 that involves translation-dependent displacement of AUF1-PABP complexes from ARE-mRNAs with possible unmasking of the poly(A) tail
— id: 64460, year: 2006, vol: 12, page: 883, stat: Journal Article,

Endotoxic shock in AUF1 knockout mice mediated by failure to degrade proinflammatory cytokine mRNAs
Lu, Jin-Yu; Sadri, Navid; Schneider, Robert J
2006 Nov 15;20(22):3174-3184, Genes & development
Excessive production of proinflammatory cytokines, particularly tumor necrosis factor-alpha (TNFalpha) and interleukin-1beta (IL-1beta), plays a critical role in septic shock induced by bacterial endotoxin (endotoxemia). Precise control of cytokine expression depends on rapid degradation of cytokine mRNAs, mediated by an AU-rich element (ARE) in the 3' noncoding region and by interacting ARE-binding proteins, which control the systemic inflammatory response. To understand the function of the ARE-binding protein AUF1, we developed an AUF1 knockout mouse. We show that AUF1 normally functions to protect against the lethal progression of endotoxemia. Upon endotoxin challenge, AUF1 knockout mice display symptoms of severe endotoxic shock, including vascular hemorrhage, intravascular coagulation, and high mortality, resulting from overproduction of TNFalpha and IL-1beta. Overexpression of these two cytokines is specific, and shown to result from an inability to rapidly degrade these mRNAs in macrophages following induction. Neutralizing antibodies to TNFalpha and IL-1beta protect AUF1 knockout mice against lethal endotoxic shock. These and other data describe a novel post-transcriptional mechanism whereby AUF1 acts as a crucial attenuator of the inflammatory response, promoting the rapid decay of selective proinflammatory cytokine mRNAs following endotoxin activation. Defects in the AUF1 post-transcriptionally controlled pathway may be involved in human inflammatory disease
— id: 69602, year: 2006, vol: 20, page: 3174, stat: Journal Article,

The cochaperone p23 differentially regulates estrogen receptor target genes and promotes tumor cell adhesion and invasion
Oxelmark, Ellinor; Roth, Jennifer M; Brooks, Peter C; Braunstein, Steven E; Schneider, Robert J; Garabedian, Michael J
2006 Jul;26(14):5205-5213, Molecular & cellular biology
The cochaperone p23 plays an important role in estrogen receptor alpha (ER) signal transduction. In this study, we investigated how p23 regulates ER target gene activation and affects tumor growth and progression. Remarkably, we found that changes in the expression of p23 differentially affected the activation of ER target genes in a manner dependent upon the type of DNA regulatory element. p23 overexpression enhanced the expression of the ER target genes cathepsin D and pS2, which are regulated by direct DNA binding of ER to estrogen response elements (ERE). In contrast, the expression of other target genes, including c-Myc, cyclin D1, and E2F1, to which ER is recruited indirectly through its interaction with other transcription factors remains unaffected by changes in p23 levels. The p23-induced expression of pS2 is associated with enhanced recruitment of ER to the ERE in the promoter, whereas ER recruitment to the ERE-less c-Myc promoter does not respond to p23. Intriguingly, p23-overexpressing MCF-7 cells exhibit increased adhesion and invasion in the presence of fibronectin. Our findings demonstrate that p23 differentially regulates ER target genes and is involved in the control of distinct cellular processes in breast tumor development, thus revealing novel functions of this cochaperone
— id: 67389, year: 2006, vol: 26, page: 5205, stat: Journal Article,

Over-expression of initiation factor eIF4G typifies inflammatory breast cancer and is crucial for tumor growth, VEGF expression and angiogenesis
Silvera, D; Formenti, SC; Schneider, RJ
2006 FEB ;100(2):S168-S168, Breast cancer research & treatment
— id: 71007, year: 2006, vol: 100, page: S168, stat: Journal Article,

CXCR6 and CXCL16 are expressed by breast cancer cells and may play a dual role in tumor progression
Wang, B; Badura, M; He, C; Cameron, T; Dustin, M; Formenti, SC; Schneider, RJ; Demaria, S
2006 FEB ;100(2):S299-S299, Breast cancer research & treatment
— id: 71013, year: 2006, vol: 100, page: S299, stat: Journal Article,

Childhood abuse and intake severity in alcohol disorder patients
Zlotnick, Caron; Johnson, Dawn M; Stout, Robert L; Zywiak, William H; Johnson, Jennifer E; Schneider, Robert J
2006 Dec;19(6):949-959, Journal of traumatic stress
In a sample of 336 patients with an alcohol use disorder, this study examined, whether patients with histories of childhood sexual abuse (CSA) and childhood physical abuse (CPA) compared to those without such histories have a greater severity of alcohol and other clinical difficulties. Whether lifetime posttraumatic stress disorder (PTSD) mediates the relationship between childhood abuse and clinical outcomes was explored. Results were that CSA was associated with earlier age of onset for alcohol disorder, greater Axis I comorbidity as defined by the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV; American Psychiatric Association, 1994), more social and psychiatric problems, but lower drinking frequency. Childhood physical abuse was related to greater drinking consequences, social and psychiatric dysfunction, and Axis I comorbidity, but also lower drinking frequency. Posttraumatic stress disorder partially mediated the effect of both CSA and CPA on severity of psychiatric problems
— id: 72044, year: 2006, vol: 19, page: 949, stat: Journal Article,

Ethical, legal, and social issues related to genomics and cancer research: the impending crisis
Ellerin, Bruce E; Schneider, Robert J; Stern, Arnold; Toniolo, Paolo G; Formenti, Silvia C
2005 Nov;2(11):919-926, Journal of the American College of Radiology : JACR
Cancer research is a multibillion-dollar enterprise validated by the clinical trial process and increasingly defined by genomics. The continued success of the endeavor depends on the smooth functioning of the clinical trial system, which in turn depends on human subject participation. Yet human subject participation can exist only in an atmosphere of trust between research participants and research sponsors, and the advent of genomics has raised a multitude of ethical, legal, and social issues that threaten this trust. The authors examine 6 of these issues: (1) informed consent; (2) privacy, confidentiality, and family disclosure dilemmas; (3) property rights in genomic discoveries; (4) individual and institutional conflicts of interest; (5) insurance and employment issues; and (6) litigation under the federal False Claims Act. The authors conclude that failure to resolve these issues may lead to a sufficient impairment of trust in genomics-based clinical trials on the part of potential research participants that the clinical trial system may implode for lack of willing participants, thus threatening the future of cancer research
— id: 72043, year: 2005, vol: 2, page: 919, stat: Journal Article,

Intra- and interfractional patient motion for a variety of immobilization devices
Engelsman, Martijn; Rosenthal, Stanley J; Michaud, Susan L; Adams, Judith A; Schneider, Robert J; Bradley, Stephen G; Flanz, Jacob B; Kooy, Hanne M
2005 Nov;32(11):3468-3474, Medical physics
The magnitude of inter- and intrafractional patient motion has been assessed for a broad set of immobilization devices. Data was analyzed for the three ordinal directions--left-right (x), sup-inf (y), and ant-post (z)--and the combined spatial displacement. We have defined 'rigid' and 'non-rigid' immobilization devices depending on whether they could be rigidly and reproducibly connected to the treatment couch or not. The mean spatial displacement for intrafractional motion for rigid devices is 1.3 mm compared to 1.9 mm for nonrigid devices. The modified Gill-Thomas-Cosman frame performed best at controlling intrafractional patient motion, with a 95% probability of observing a three-dimensional (3D) vector length of motion (v95) of less than 1.8 mm, but could not be evaluated for interfractional motion. All other rigid and nonrigid immobilization devices had a v95 of more than 3 mm for intrafractional patient motion. Interfractional patient motion was only evaluated for the rigid devices. The mean total interfractional displacement was at least 3.0 mm for these devices while v95 was at least 6.0 mm
— id: 72047, year: 2005, vol: 32, page: 3468, stat: Journal Article,

Overexpression of a critical target of rapamycin, translation regulatory protein 4E-BP1, is largely restricted to locally advanced breast and prostrate cancers and is lost with tumor invasiveness
Schneider, Robert J.; Kharpasheva, Ksen; Formenti, Silvia; Braunstein, Steven; Connolly, Eileen
2004 ;45(6):1158-1159, Proceedings (American Association for Cancer Research)
— id: 109232, year: 2004, vol: 45, page: 1158, stat: Journal Article,

Hepatitis B Virus HBx Protein Activation of Cyclin A-Cyclin-Dependent Kinase 2 Complexes and G(1) Transit via a Src Kinase Pathway
Bouchard M; Giannakopoulos S; Wang EH; Tanese N; Schneider RJ
2001 May;75(9):4247-4257, Journal of virology
Numerous studies have demonstrated that the hepatitis B virus HBx protein stimulates signal transduction pathways and may bind to certain transcription factors, particularly the cyclic AMP response element binding protein, CREB. HBx has also been shown to promote early cell cycle progression, possibly by functionally replacing the TATA-binding protein-associated factor 250 (TAF(II)250), a transcriptional coactivator, and/or by stimulating cytoplasmic signal transduction pathways. To understand the basis for early cell cycle progression mediated by HBx, we characterized the molecular mechanism by which HBx promotes deregulation of the G(0) and G(1) cell cycle checkpoints in growth-arrested cells. We demonstrate that TAF(II)250 is absolutely required for HBx activation of the cyclin A promoter and for promotion of early cell cycle transit from G(0) through G(1). Thus, HBx does not functionally replace TAF(II)250 for transcriptional activity or for cell cycle progression, in contrast to a previous report. Instead, HBx is shown to activate the cyclin A promoter, induce cyclin A-cyclin-dependent kinase 2 complexes, and promote cycling of growth-arrested cells into G(1) through a pathway involving activation of Src tyrosine kinases. HBx stimulation of Src kinases and cyclin gene expression was found to force growth-arrested cells to transit through G(1) but to stall at the junction with S phase, which may be important for viral replication
— id: 19695, year: 2001, vol: 75, page: 4247, stat: Journal Article,

Calcium signaling by HBx protein in hepatitis B virus DNA replication
Bouchard, M J; Wang, L H; Schneider, R J
2001 Dec 14;294(5550):2376-2378, Science
Hepatitis B virus (HBV) infects more than 300 million people and is a leading cause of liver cancer and disease. The HBV HBx protein is essential for infection; HBx activation of Src is important for HBV DNA replication. In our study, HBx activated cytosolic calcium-dependent proline-rich tyrosine kinase-2 (Pyk2), a Src kinase activator. HBx activation of HBV DNA replication was blocked by inhibiting Pyk2 or calcium signaling mediated by mitochondrial calcium channels, which suggests that HBx targets mitochondrial calcium regulation. Reagents that increased cytosolic calcium substituted for HBx protein in HBV DNA replication. Thus, alteration of cytosolic calcium was a fundamental requirement for HBV replication and was mediated by HBx protein
— id: 133548, year: 2001, vol: 294, page: 2376, stat: Journal Article,

Hepatitis B virus
Schneider RJ; Ganem D
Fields' virology Philadelphia : Lippincott Williams & Wilkins, 2001,
— id: 2603, year: 2001, vol: , page: ?, stat: Chapter,

Hepatitis B virus
Schneider RJ; Ganem D
Fundamental virology Philadelphia : Lippincott Williams & Wilkins, 2001,
— id: 2604, year: 2001, vol: , page: ?, stat: Chapter,

Calcium-induced stabilization of AU-rich short-lived mRNAs is a common default response
Klein N; Curatola AM; Schneider RJ
1999 ;7(4-6):357-365, Gene expression
The AU-rich element (AUUUA)n, found in the 3' noncoding region of many short-lived cytokine and proto-oncogene mRNAs, is sufficient to specifically target these mRNAs for rapid degradation in mammalian cells. The mechanism by which the AU-rich element promotes rapid mRNA decay is not known. Previous studies have shown that release of intracellular stored calcium by ionophore treatment of thymocytes and mast cells inhibits the rapid turnover of AU-rich interleukin mRNAs. Increased cytoplasmic half-life of interleukin mRNAs was linked to calcium-induced activation of the N-terminal c-Jun kinase. In this report we have characterized the calcium-induced stabilization of AU-rich mRNAs. We show that calcium induces stabilization of mRNAs with canonical AU-rich elements in all cell types tested. These results indicate that short-lived mRNA stabilization by calcium is not unique to immune cells nor interleukin mRNAs, but is a widespread default response that includes generic AU-rich mRNAs. Stabilization is shown to be rapid but transient, and to act without altering nuclear transcription or cytoplasmic translation rates. These data support the view that calcium release likely stabilizes short-lived mRNAs by altering trans-acting decay factors that promote AU-rich mRNA turnover
— id: 6173, year: 1999, vol: 7, page: 357, stat: Journal Article,

Expression of glutamate receptor-binding PDZ proteins from adenovirus vectors in the CNS in vitro and in vivo
Akaneya, Y.; States, B.; Khatri, L.; Schneider, R.; Ziff, E. B.
1998 ;24(1-2):571-571, Abstracts (Society for Neuroscience)
— id: 92645, year: 1998, vol: 24, page: 571, stat: Journal Article,

Hepatitis B virus HBx protein induces transcription factor AP-1 by activation of extracellular signal-regulated and c-Jun N-terminal mitogen-activated protein kinases
Benn J; Su F; Doria M; Schneider RJ
1996 Aug;70(8):4978-4985, Journal of virology
The HBx protein of hepatitis B virus is a dual-specificity activator of transcription, stimulating signal transduction pathways in the cytoplasm and transcription factors in the nucleus, when expressed in cell lines in culture. In the cytoplasm, HBx was shown to stimulate the Ras-Raf-mitogen-activated protein kinase (MAP kinase) cascade, which is essential for activation of transcription factor AP-1. Here we show that HBx protein stimulates two independently regulated members of the MAP kinase family when expressed transiently in cells. HBx protein stimulates the extracellular signal-regulated kinases (ERKs) and the c-Jun N-terminal kinases (JNKs). HBx activation of ERKs and JNKs leads to induction and activation of AP-1 DNA binding activity involving transient de novo synthesis of c-Fos protein and prolonged synthesis of c-Jun, mediated by N-terminal phosphorylation of c-Jun carried out by HBx-activated JNK. New c-Jun synthesis was blocked by coexpression with a dominant-negative MAP kinase kinase (MEK kinase, MEKK-1), confirming that HBx stimulates the prolonged synthesis of c-Jun by activating JNK signalling pathways. Activation of the c-fos gene was blocked by coexpression with a Raf-C4 catalytic mutant, confirming that HBx induces c-Fos by acting on Ras-Raf linked pathways. HBx activation of ERK and JNK pathways resulted in prolonged accumulation of AP-1-c-Jun dimer complexes. HBx activation of JNK and sustained activation of c-jun, should they occur in the context of hepatitis B virus infection, might play a role in viral transformation and pathogenesis
— id: 6980, year: 1996, vol: 70, page: 4978, stat: Journal Article,

Cap-binding protein (eukaryotic initiation factor 4E) and 4E-inactivating protein BP-1 independently regulate cap-dependent translation
Feigenblum D; Schneider RJ
1996 Oct;16(10):5450-5457, Molecular & cellular biology
Cap-dependent protein synthesis in animal cells is inhibited by heat shock, serum deprivation, metaphase arrest, and infection with certain viruses such as adenovirus (Ad). At a mechanistic level, translation of capped mRNAs is inhibited by dephosphorylation of eukaryotic initiation factor 4E (eIF-4E) (cap-binding protein) and its physical sequestration with the translation repressor protein BP-1 (PHAS-I). Dephosphorylation of BP-I blocks cap-dependent translation by promoting sequestration of eIF-4E. Here we show that heat shock inhibits translation of capped mRNAs by simultaneously inducing dephosphorylation of eIF-4E and BP-1, suggesting that cells might coordinately regulate translation of capped mRNAs by impairing both the activity and the availability of eIF-4E. Like heat shock, late Ad infection is shown to induce dephosphorylation of eIF-4E. However, in contrast to heat shock, Ad also induces phosphorylation of BP-1 and release of eIF-4E. BP-1 and eIF-4E can therefore act on cap-dependent translation in either a mutually antagonistic or cooperative manner. Three sets of experiments further underscore this point: (i) rapamycin is shown to block phosphorylation of BP-1 without inhibiting dephosphorylation of eIF-4E induced by heat shock or Ad infection, (ii) eIF-4E is efficiently dephosphorylated during heat shock or Ad infection regardless of whether it is in a complex with BP-1, and (iii) BP-1 is associated with eIF-4E in vivo regardless of the state of eIF-4E phosphorylation. These and other studies establish that inhibition of cap-dependent translation does not obligatorily involve sequestration of eIF-4E by BP-1. Rather, translation is independently regulated by the phosphorylation states of eIF-4E and the 4E-binding protein, BP-1. In addition, these results demonstrate that BP-1 and eIF-4E can act either in concert or in opposition to independently regulate cap-dependent translation. We suggest that independent regulation of eIF-4E and BP-1 might finely regulate the efficiency of translation initiation or possibly control cap-dependent translation for fundamentally different purposes
— id: 7069, year: 1996, vol: 16, page: 5450, stat: Journal Article,

Hepatitis B virus HBx protein activates transcription factor NF-kappaB by acting on multiple cytoplasmic inhibitors of rel-related proteins
Su F; Schneider RJ
1996 Jul;70(7):4558-4566, Journal of virology
The HBx protein is a small polypeptide encoded by mammalian hepadnaviruses that is essential for viral infectivity and is thought to play a role in development of hepatocellular carcinoma during chronic hepatitis B virus infection. HBx is a transactivator that stimulates Ras signal transduction pathways in the cytoplasm and certain transcription elements in the nucleus. To better understand the activities of HBx protein and its mechanism of action, we have explored the manner by which HBx activates the transcription factor NF-kappaB during transient expression. We show that HBx induces prolonged formation, in a Ras-dependent manner, of transcriptionally active NF-kappaB DNA-binding complexes, which make up the family of Rel-related proteins, p50, p52, RelA, and c-Rel. HBx was found to activate NF-kappaB through two distinct cytoplasmic pathways by acting on both the 37-kDa IkappaBalpha inhibitor and the 105-kappaDa NF-kappaB1 precursor inhibitor protein, known as p105. HBx induces phosphorylation of IkappaBalpha, a three- to fourfold reduction in IKBalpha stability, and concomitant nuclear accumulation of NF-kappaB DNA-binding complexes, similar to that reported for human T-cell leukemia virus type 1 Tax protein. In addition, HBx mediates a striking reduction in cytoplasmic p105 NF-kappaB1 inhibitor and p50 protein levels and release of RelA protein that was sequestered by the p105 inhibitor, concomitant with nuclear accumulation of NF-kappaB complexes. HBx mediated only a slight reduction in the cytoplasmic levels of NF-kappaB2 p100 protein, an additional precursor inhibitor of NF-kappaB, which is thought to be less efficiently processed or less responsive to release of NF-kappaB. No evidence was found for HBx activation of NF-kappaB by targeting acidic sphingomyelinase- controlled pathways. Studies also suggest that stimulation of NF-kappaB by HBx does not involve activation of Ras via the neutral sphingomyelin-ceramide pathway. Thus, HBx protein is shown to activate the NF-kappaB family of Rel-related proteins by acting on two distinct NF-kappaB cytoplasmic inhibitors
— id: 8015, year: 1996, vol: 70, page: 4558, stat: Journal Article,

Selective translation initiation by ribosome jumping in adenovirus-infected and heat-shocked cells
Yueh A; Schneider RJ
1996 Jun 15;10(12):1557-1567, Genes & development
Translation initiation on eukaryotic mRNAs usually occurs by 5'-processive scanning of 40S ribosome subunits from the m7GTP-cap to the initiating AUG. In contrast, picornavirus and some specialized mRNAS initiate translation by internally binding ribosomes. A poorly described third mechanism of initiation, referred to as ribosome shunting or jumping, involves discontinuous scanning by 40S ribosome subunits, in which large segments of the 5' noncoding region are bypassed. Ribosome shunting has only been observed to date on a cauliflower mosaic virus mRNA. In this report we show that the family of adenovirus late mRNAs, which are preferentially translated during infection, use a ribosome jumping mechanism to initiate protein synthesis. Late adenovirus mRNAs contain a common 5'-noncoding region known as the tripartite leader, which confers preferential translation by reducing the requirement for the rate-limiting initiation factor eIF-4F (cap-binding protein complex). Adenovirus inhibits cell protein synthesis largely by inactivating eIF-4F. We show that the tripartite leader directs both 5' linear ribosome scanning and ribosome jumping when eIF-4F is abundant but exclusively uses a ribosome jumping mechanism during late adenovirus infection or heat shock (stress) of mammalian cells, when eIF-4F is altered or inactivated. Shunting is directed by a complex group of secondary structures in the tripartite leader and is facilitated by one or more unidentified viral late gene products. We propose that shunting may represent a widespread mechanism to facilitate selective translation of specialized classes of capped mRNAs, including some stress and developmentally regulated mRNAs, which possess little requirement for eIF-4F but do not initiate by internal ribosome binding
— id: 8018, year: 1996, vol: 10, page: 1557, stat: Journal Article,

HCV REPLICATIVE INTERMEDIATES AS A PREDICTOR OF DISEASE-ACTIVITY AFTER LIVER-TRANSPLANTATION
BRODY, RI; MIZRACHI, HH; TEPERMAN, LW; SCHNEIDER, RJ
1995 JAN ;72(1):A128-A128, Laboratory investigation
— id: 87437, year: 1995, vol: 72, page: A128, stat: Journal Article,

Rapid degradation of AU-rich element (ARE) mRNAs is activated by ribosome transit and blocked by secondary structure at any position 5' to the ARE
Curatola AM; Nadal MS; Schneider RJ
1995 Nov;15(11):6331-6340, Molecular & cellular biology
The 3' noncoding region (NCR) AU-rich element (ARE) selectively confers rapid degradation on many mRNAs via a process requiring translation of the message. The role of cotranslation in destabilization of ARE mRNAs was examined by insertion of translation-blocking stable secondary structure at different sites in test mRNAs containing either the granulocyte-macrophage colony-stimulating factor (GM-CSF) ARE or a control sequence. A strong (-80 kcal/mol [1 kcal = 4.184 kJ]) but not a moderate (-30 kcal/mol) secondary structure prevented destabilization of mRNAs when inserted at any position upstream of the ARE, including in the 3' NCR. Surprisingly, a strong secondary structure did not block rapid mRNA decay when placed immediately downstream of the ARE. Studies are also presented showing that the turnover of mRNAs containing control or ARE sequences is not altered by insertion of long (1,000-nucleotide) intervening segments between the stop codon and the ARE or between the ARE and poly(A) tail. Characterization of ARE-containing mRNAs in polyadenylated and whole cytoplasmic RNA fractions failed to find evidence for decay intermediates degraded to the site of strong secondary structure from either the 5' or 3' end. From these and other data presented, this study demonstrates that complete translation of the coding region is essential for activation of rapid mRNA decay controlled by the GM-CSF ARE and that the structure of the 3' NCR can strongly influence activation. The results are consistent with activation of ARE-mediated decay by possible entry of translation-linked decay factors into the 3' NCR or translation-coupled changes in 3' NCR ribonucleoprotein structure or composition
— id: 7922, year: 1995, vol: 15, page: 6331, stat: Journal Article,

THE RELATIONSHIP OF HORMONAL AND IMMUNOLOGICAL RESPONSES TO STRESS IN TYPE A BEHAVIOR
BLASDELL K S; MILLS P; WALLACE R K; VANZANDT W L; SCHNEIDER R; WALTON K; HILL D
1987 ;13(2):1295-1295, Abstracts (Society for Neuroscience)
— id: 92467, year: 1987, vol: 13, page: 1295, stat: Journal Article,