Dataset Information

Expression of GITR Enhances Multiple Myeloma Cell Sensitivity to Bortezomib.

ABSTRACT: Recently tumor necrosis factor receptor super family member 18 (TNFRSF18, also called GITR) has been identified as a novel tumor suppressor gene in Multiple Myeloma (MM), undergoing aberrant DNA methylation-mediated gene expression silencing. Furthermore, the expression of GITR blocks canonical NF-?B activation in MM cells in response to TNF?. Bortezomib, a proteasome inhibitor, can induce NF-?B activation, which may significantly influence the drug response in MM patients. In this study, we aim to elucidate if GITR status is associated with response to Bortezomib in MM cells through regulating GITR mediated NF-?B blockade. We found that GITR was significantly downregulated in MM patients and cell lines. Overexpression of GITR inhibited non-canonical NF-?B activation induced by TNF?. Moreover, NF-?B inhibitor induced apoptosis in GITR-deficient MM cells in response to TNF?. In addition, overexpression of GITR could inhibit Bortezomib-induced NF-?B activation and enhance the cytotoxicity of Bortezomib in GITR-deficient MM cell line (MM1.S). In contrast, knockdown of GITR attenuated the cytotoxic effect of Bortezomib on GITR proficient MM (RPMI) cell line and increased NF-?B activation. Finally, overexpression of GITR enhanced the sensitivity to Bortezomib in co-culture with bone marrow stromal cells and significantly reduced the tumor growth in MM1.S xenograft mice. In conclusion, we demonstrated that GITR expression can enhance the sensitivity to Bortezomib by inhibiting Bortezomib-induced NF-?B activation.

SUBMITTER: Zhao Y

PROVIDER: S-EPMC4431824 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Expression of GITR Enhances Multiple Myeloma Cell Sensitivity to Bortezomib.

Zhao Yinghao Y Zhang Kun K Li Guangquan G Zhang Xingyi X Shi Donglei D

PloS one 20150514 5

Recently tumor necrosis factor receptor super family member 18 (TNFRSF18, also called GITR) has been identified as a novel tumor suppressor gene in Multiple Myeloma (MM), undergoing aberrant DNA methylation-mediated gene expression silencing. Furthermore, the expression of GITR blocks canonical NF-κB activation in MM cells in response to TNFα. Bortezomib, a proteasome inhibitor, can induce NF-κB activation, which may significantly influence the drug response in MM patients. In this study, we aim ...[more]

PMID: 25973846

Similar Datasets

Project description:The MAGE-C1/CT7 encodes a cancer/testis antigen (CTA), is located on the chromosomal region Xq26-27 and is highly polymorphic in humans. MAGE-C1/CT7 is frequently expressed in multiple myeloma (MM) that may be a potential target for immunotherapy in this still incurable disease. MAGEC1/CT7 expression is restricted to malignant plasma cells and it has been suggested that MAGE-C1/CT7 might play a pathogenic role in MM; however, the exact function this protein in the pathophysiology of MM is not yet understood. Our objectives were (1) to clarify the role of MAGE-C1/CT7 in the control of cellular proliferation and cell cycle in myeloma and (2) to evaluate the impact of silencing MAGE-C1/CT7 on myeloma cells treated with bortezomib. Myeloma cell line SKO-007 was transduced for stable expression of shRNA-MAGE-C1/CT7. Downregulation of MAGE-C1/CT7 was confirmed by real time quantitative PCR and western blot. Functional assays included cell proliferation, cell invasion, cell cycle analysis and apoptosis. Western blot showed a 70-80% decrease in MAGE-C1/CT7 protein expression in inhibited cells (shRNA-MAGE-C1/CT7) when compared with controls. Functional assays did not indicate a difference in cell proliferation and DNA synthesis when inhibited cells were compared with controls. However, we found a decreased percentage of cells in the G2/M phase of the cell cycle among inhibited cells, but not in the controls (p<0.05). When myeloma cells were treated with bortezomib, we observed a 48% reduction of cells in the G2/M phase among inhibited cells while controls showed 13% (empty vector) and 9% (ineffective shRNA) reduction, respectively (p<0.01). Furthermore, inhibited cells treated with bortezomib showed an increased percentage of apoptotic cells (Annexin V+/PI-) in comparison with bortezomib-treated controls (p<0.001). We found that MAGE-C1/CT7 protects SKO-007 cells against bortezomib-induced apoptosis. Therefore, we could speculate that MAGE-C1/CT7 gene therapy could be a strategy for future therapies in MM, in particular in combination with proteasome inhibitors.

Project description:Multiple myeloma (MM) is an incurable plasma cell malignancy with poor survival. Autophagy, a stress-responsive catabolic process mediated by lysosomal activity, plays a crucial role in the pathophysiology of MM. Growing evidence has indicated that dysregulated microRNAs (miRNAs) are associated with the aberrant autophagy in various human cancers. However, to date, few miRNAs have been reported to directly modulate autophagy in the pathobiology of MM. In this study, we investigated the role of MIR145-3p (microRNA 145-3p) in MM, with focus on cellular processes autophagy and cell death. Our results provided evidence that downregulation of MIR145-3p expression was associated with disease progression in human MM. MIR145-3p triggered autophagic flux through direct targeting of HDAC4 (histone deacetylase 4) in MM cells, leading to enhanced apoptosis. Silencing HDAC4 recapitulated the effects of MIR145-3p, whereas enforced expression of HDAC4 abrogated the effects of MIR145-3p. Furthermore, we showed that suppression of HDAC4 by MIR145-3p resulted in upregulation of the pro-apoptotic protein BCL2L11 and caused MTORC1 inactivation, which in turn led to enhanced autophagy and cell death. Importantly, we demonstrated that MIR145-3p mimic could potentiate the anti-MM activity of bortezomib in both in vitro and in vivo experiments. Overall, our findings indicate that MIR145-3p exerted a tumor suppression function in MM by inducing autophagic cell death and suggest that MIR145-3p-based targeted therapy would represent a novel strategy for MM treatment.Abbreviations: 3-MA: 3-methyladenine; 3'-UTR: 3'-untranslated region; 7-AAD: 7-aminoactinomycin D; ACTB: actin beta; ANXA5: annexin A5; ATG5: autophagy related 5; ATG7: autophagy related 7; B2M: beta-2-microglobulin; BAF: bafilomycin A1; BCL2L11: BCL2 like 11; Bort: bortezomib; CASP3: caspase 3; CCK-8: Cell Counting Kit-8; CQ: chloroquine; Ct: threshold cycle; ctrl: control; DAPI: 4',6-diamidino-2-phenylindole; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GFP: green fluorescent protein; HDAC4: histone deacetylase 4; ISS: International Staging System; MAP1LC3B: microtubule associated protein 1 light chain 3 beta; miRNAs: microRNAs; MIR145-3p: microRNA 145-3p; MM: multiple myeloma; mRNA: messenger RNA; MTOR: mechanistic target of rapamycin kinase; MTORC1: mechanistic target of rapamycin kinase complex 1; PCs: plasma cells; PFS: progression-free survival; qRT-PCR: quantitative reverse transcription PCR; RPS6KB1: ribosomal protein S6 kinase B1; SD: standard deviation; siRNA: small interfering RNA; SQSTM1: sequestosome 1; STV: starvation; TUBB: tubulin beta class I.

Project description:BackgroundMultiple myeloma (MM) is an incurable plasma cell malignancy. Although Dexamethasone (Dex) is the most widely used therapeutic drug in MM treatment, patients develop Dex resistance leading to progressive disease, demanding an urgent need to investigate the mechanisms driving Dex resistance and develop new reagents to address this problem. We propose SUMOylation as a potential mechanism regulating Dex resistance and SUMOylation inhibition can enhance Dex sensitivity in MM.MethodsUsing MM cell lines and primary MM samples from relapsing MM patients, we evaluated the effects of knockdown of SUMO E1 (SAE2) or using TAK-981, a novel and specific SUMO E1 inhibitor, on Dex sensitivity. Xenograft mouse models were generated to determine the in vivo anti-MM effects of TAK-981 as a single agent and in combination with Dex. miRNA-seq, RNA-seq and GSEA analysis were utilized for evaluating key factors mediating Dex resistance. Chromatin immunoprecipitation (ChIP) assay was performed to determine the binding occupancy of c-Myc on promoter region of miRs.ResultsWe observed a significant negative correlation between SUMO E1 (SAE2) expression and Dex sensitivity in primary MM samples. Knockdown of SAE2 or using TAK-981 significantly enhances myeloma sensitivity to Dex in MM cell lines. Moreover, the enhanced anti-MM activity by TAK-981 and Dex combination has been validated using primary relapsing MM patient samples and xenograft mouse models. SUMOylation inhibition increased glucocorticoid receptor (GR) expression via downregulation miR-130b. Using RNA and microRNA sequencing, we identified miR-551b and miR-25 as important miRs mediating Dex resistance in MM. Overexpression of miR-551b and miR-25 caused resistance to Dex, however, knockdown of miR-551b and miR-25 significantly enhanced Dex sensitivity in MM. SAE2 knockdown or TAK-981 treatment downregulated the expression of miR-551b and miR-25, leading to induction of miR targets ZFP36, ULK1 and p27, resulting in apoptosis and autophagy. We demonstrated c-Myc as a major transcriptional activator of miR-130b, miR-551b and miR-25 and SUMOylation inhibition downregulates these miRs level by decreasing c-Myc level.ConclusionOur study proves SUMOylation plays a crucial role in Dex resistance in MM and SUMOylation inhibition appears to be an attractive strategy to advance to the clinic for MM patients.

Dataset Information

Expression of GITR Enhances Multiple Myeloma Cell Sensitivity to Bortezomib.

Publications

Expression of GITR Enhances Multiple Myeloma Cell Sensitivity to Bortezomib.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets