Project description:Proteasome inhibitors are important chemotherapeutics in the treatment of multiple myeloma, but they are currently used empirically as no markers of sensitivity have been validated. We have identified expression of tight junction protein (TJP) 1 as being associated with sensitivity of plasma cells in vitro and in vivo to proteasome inhibitors. TJP1 suppressed expression of genes in the major histocompatibility class II region, including two catalytically active immunoproteasome subunits, thereby decreasing proteasome activity, a critical determinant of proteasome inhibitor sensitivity. This occurred through suppression by TJP1 of signaling through the epidermal growth factor receptor/Janus kinase 1/signal transducer and activator of transcription 3 pathway. In the clinic, high TJP1 expression in myeloma patients was associated with a significantly higher likelihood of responding to bortezomib, and with a longer time-to-progression after treatment. Taken together, these data support the use of TJP1 as a biomarker of sensitivity and resistance to proteasome inhibitors. To further elucidate mechanisms of bortezomib resistance, we developed human-derived multiple myeloma cell lines with a 4-fold or greater resistance to bortezomib. Then total RNA for bortezomib resistant (BR) and wild type (WT) was extracted and used for comparison by gene expression profiling.
Project description:The estrogen receptor-alpha (ERα) determines breast cancer cell phenotype and is a prognostic indicator. A better understanding of the mechanisms controlling ERα function may uncover improved strategies for the treatment of breast cancer. Proteasome inhibition was previously reported to regulate estrogen-induced transcription but the mechanisms by which it influences ERα function remain controversial. In this study we investigated the transcriptome-wide effects of the proteasome inhibitor Velcade on estrogen-regulated transcription in MCF7 human breast cancer cells and demonstrate a specific global decrease in estrogen-induced transcription. This set contains 12 microarray samples. 3 controls, 3 estrogen stimulated, 3 Bortezomib stimulated, 3 Bortezomib + estrogen stimulated
Project description:Proteasome inhibitors are important chemotherapeutics in the treatment of multiple myeloma, but they are currently used empirically as no markers of sensitivity have been validated. We have identified expression of tight junction protein (TJP) 1 as being associated with sensitivity of plasma cells in vitro and in vivo to proteasome inhibitors. TJP1 suppressed expression of genes in the major histocompatibility class II region, including two catalytically active immunoproteasome subunits, thereby decreasing proteasome activity, a critical determinant of proteasome inhibitor sensitivity. This occurred through suppression by TJP1 of signaling through the epidermal growth factor receptor/Janus kinase 1/signal transducer and activator of transcription 3 pathway. In the clinic, high TJP1 expression in myeloma patients was associated with a significantly higher likelihood of responding to bortezomib, and with a longer time-to-progression after treatment. Taken together, these data support the use of TJP1 as a biomarker of sensitivity and resistance to proteasome inhibitors.
Project description:The estrogen receptor-alpha (ERα) determines breast cancer cell phenotype and is a prognostic indicator. A better understanding of the mechanisms controlling ERα function may uncover improved strategies for the treatment of breast cancer. Proteasome inhibition was previously reported to regulate estrogen-induced transcription but the mechanisms by which it influences ERα function remain controversial. In this study we investigated the transcriptome-wide effects of the proteasome inhibitor Velcade on estrogen-regulated transcription in MCF7 human breast cancer cells and demonstrate a specific global decrease in estrogen-induced transcription. This set contains 21 microarray samples. 3 controls, 3 estrogen stimulated, 3 Bortezomib + estrogen stimulated, 2* 3 siRNA controls, 3 siRNA PSMB3 knockdowns, 3 siRNA PSMB5 knockdowns
Project description:The estrogen receptor-alpha (ERα) determines breast cancer cell phenotype and is a prognostic indicator. A better understanding of the mechanisms controlling ERα function may uncover improved strategies for the treatment of breast cancer. Proteasome inhibition was previously reported to regulate estrogen-induced transcription but the mechanisms by which it influences ERα function remain controversial. In this study we investigated the transcriptome-wide effects of the proteasome inhibitor Velcade on estrogen-regulated transcription in MCF7 human breast cancer cells and demonstrate a specific global decrease in estrogen-induced transcription.
Project description:The estrogen receptor-alpha (ERα) determines breast cancer cell phenotype and is a prognostic indicator. A better understanding of the mechanisms controlling ERα function may uncover improved strategies for the treatment of breast cancer. Proteasome inhibition was previously reported to regulate estrogen-induced transcription but the mechanisms by which it influences ERα function remain controversial. In this study we investigated the transcriptome-wide effects of the proteasome inhibitor Velcade on estrogen-regulated transcription in MCF7 human breast cancer cells and demonstrate a specific global decrease in estrogen-induced transcription.
Project description:Proteasome activity is crucial for cellular integrity, but how tissues adjust proteasome content in response to catabolic stimuli is uncertain. Here, we demonstrate that transcriptional coordination by multiple transcription factors is required to increase proteasome content and activate proteolysis in catabolic states. Using denervated mouse muscle as a model system for accelerated proteolysis in vivo, we reveal that a two-phase transcriptional program activates genes encoding proteasome subunits and assembly chaperones to boost an increase in proteasome content. Initially, gene induction is necessary to maintain basal proteasome levels, and in a more delayed phase (7-10 d after denervation) it stimulates proteasome assembly to meet cellular demand for excessive proteolysis. Intriguingly, the transcription factors PAX4 and α-PALNRF-1 control the expression of proteasome among other genes in a combinatorial manner, driving cellular adaptation to muscle denervation. Consequently, PAX4 and α-PALNRF-1 represent new therapeutic targets to inhibit proteolysis in catabolic diseases (e.g. type-2 diabetes, cancer).