Project description:The combination of bortezomib and dexamethasone should become the reference induction treatment for multiple myeloma patients younger than 65 years. Pharmacogenomic profiles of genes involved in response to treatment may help to understand resistance. We performed gene expression profiling in 9 myeloma cell lines, incubated or not with bortezomib and dexamethasone for 6 hours. Supervised analysis identified significantly up regulated genes involved in stress responses. We focused on REDD1 a gene known to be rapidly induced by a wide variety of stress conditions and DNA damages. REDD1 expression was early and highly induced after bortezomib exposure. REDD1 induction was associated with the dephosphorylation of P70 S6 ribosomal kinase (P70S6K), a key substrate of mTOR. These effects were dependent upon cell line. REDD1 was overexpressed within two hours in bortezomib resistant cell lines in association with a cell size decrease. In sensitive cell lines, neither REDD1 induction nor morphological changes occurred. RNA interference mediated inhibition of REDD1 induction abrogates P70S6K dephosphorylation, early transitory cell size reduction and enhances sensitivity to bortezomib - dexamethasone. Our results suggest that mTOR regulation could be a resistance mechanism mediated by REDD1 expression in myeloma cells. Nine cell lines of multiple myeloma studied, incubated or not with bortezomib and dexamethasone, examined with spotted cDNA nylon membrane. Cell line and Code : JJN3 = Vel_1x; L363 = Vel_2x; LP1 = Vel_3x; MDN = Vel_4x; NCI = Vel_5x; RPMI = Vel_6x; SBN = Vel_7x; U266 = Vel_8x; XG1 = Vel_9x.
Project description:The combination of bortezomib and dexamethasone should become the reference induction treatment for multiple myeloma patients younger than 65 years. Pharmacogenomic profiles of genes involved in response to treatment may help to understand resistance. We performed gene expression profiling in 9 myeloma cell lines, incubated or not with bortezomib and dexamethasone for 6 hours. Supervised analysis identified significantly up regulated genes involved in stress responses. We focused on REDD1 a gene known to be rapidly induced by a wide variety of stress conditions and DNA damages. REDD1 expression was early and highly induced after bortezomib exposure. REDD1 induction was associated with the dephosphorylation of P70 S6 ribosomal kinase (P70S6K), a key substrate of mTOR. These effects were dependent upon cell line. REDD1 was overexpressed within two hours in bortezomib resistant cell lines in association with a cell size decrease. In sensitive cell lines, neither REDD1 induction nor morphological changes occurred. RNA interference mediated inhibition of REDD1 induction abrogates P70S6K dephosphorylation, early transitory cell size reduction and enhances sensitivity to bortezomib - dexamethasone. Our results suggest that mTOR regulation could be a resistance mechanism mediated by REDD1 expression in myeloma cells.
Project description:The PI3K/mTOR pathway is a constitutively active in multiple myeloma. Single inhibition of mTOR usually confers reactivation of the pathway. VS-5584 (SB2343) is a bispecific PI3K/mTOR inhibitor which effectively and specifically inhibits the target pathways and shows potent anti-myeloma activity. We utilised a gene microarray analysis to analyse and identify the genes that were sensitively regulated by VS-5584 treatment in OPM2.
Project description:The PI3K/mTOR pathway is a constitutively active in multiple myeloma. Single inhibition of mTOR usually confers reactivation of the pathway. VS-5584 (SB2343) is a bispecific PI3K/mTOR inhibitor which effectively and specifically inhibits the target pathways and shows potent anti-myeloma activity. We utilised a gene microarray analysis to analyse and identify the genes that were sensitively regulated by VS-5584 treatment in OPM2. OPM2 cells were either treated with DMSO(drug solvent) or with 125nM of VS-5584(SB2343) which is half the IC50 concentration of the drug at 48h in OPM2 cells. The cells were harvested at 24h in order to detect the regulation of relatively early response genes.
Project description:To investigate the role of iron(FeAc) on bortezomib-induced drug resistance of multiple myeloma cells, we administrated MM.1S with iron and bortezomib
Project description:The aims of this study were to assess the feasibility of prospective pharmacogenomics research in multicenter international clinical trials of bortezomib in multiple myeloma and to develop predictive classifiers of response and survival with bortezomib. Patients with relapsed myeloma enrolled in phase 2 and phase 3 clinical trials of bortezomib and consented to genomic analyses of pretreatment tumor samples. Bone marrow aspirates were subject to a negative-selection procedure to enrich for tumor cells, and these samples were used for gene expression profiling using DNA microarrays. Data quality and correlations with trial outcomes were assessed by multiple groups. Gene expression in this dataset was consistent with data published from a single-center study of newly diagnosed multiple myeloma. Response and survival classifiers were developed and shown to be significantly associated with outcome via testing on independent data. The survival classifier improved on the risk stratification provided by the International Staging System. Predictive models and biologic correlates of response show some specificity for bortezomib rather than dexamethasone. Informative gene expression data and genomic classifiers that predict clinical outcome can be derived from prospective clinical trials of new anticancer agents. Experiment Overall Design: Purified myeloma samples were collected prior to enrolment in clinical trials of bortezomib (PS-341). Samples were subject to replicate gene expression profiling using the Affymetrix 133A/B microarray. Data was normalized in MAS5.0 and the median of replicates is reported. Data was normalized to a Ttimmed mean of 15o and is NOT log transformed. Various patient parameters are reported as well as response, TTP and survival upon treatment with bortezomib or dexamethasone.
Project description:Bortezomib therapy has been proven successful for the treatment of relapsed and/or refractory multiple myeloma (MM). However, both intrinsic and acquired resistance has already been observed. In this study, we explored the relationship between CD9 expression and bortezomib sensitivity in MM Both intrinsic and acquired resistance has already been observed. In this study, we explored the relationship between CD9 expression and bortezomib sensitivity in MM. We found that down-regulation of CD9 by methylation decreased bortezomib sensitivity in multiple myeloma.
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:To investigate the role of coculture treatment of multiple myeloma cells to bortezomib drug resistance, multiple myeloma cells were cocultured with bone marrow mesechymal stem cells
Project description:Even though cutaneous atrophy is the major adverse effect of topical glucocorticoids, its molecular mechanisms are poorly understood. We found that glucocorticoids strongly increased the expression of REDD1 (regulated in development and DNA damage response 1), a stress-inducible inhibitor of mTOR, in mouse and human epidermis. We found that REDD1 knockout animals are partially resistant to glucocorticoid-induced epidermal and subcutaneous adipose atrophy which correlated with the protection of CD34+ follicular epithelial stem cells as well as p63+ keratinocyte progenitors in REDD1 knockout epidermis during chronic steroid treatment. At the same time, REDD1 knockout did not affect anti- inflammatory effect of glucocorticoids, as evaluated by ear edema test. Expression profiling revealed that ~ 50% of the glucocorticoid receptor (GR) target genes were not activated in epidermis of REDD1 knockouts, however, the negative effect of glucocorticoids on gene expression was similar to that in w.t. animals. Overall, our findings reveal a novel pathway in GR activation by its target gene/protein REDD1; and indicate an important role of REDD1 in glucocorticoid-induced skin atrophy, and maintenance of the epidermis and subcutaneous adipose. In addition, our findings form the foundation for the development of safer topical glucocorticoid treatment regimens by combining this therapy with REDD1 inhibitors.