Dataset Information

Role for microRNAs in regulating glucocorticoid response and resistance in multiple myeloma.

ABSTRACT: Glucocorticoids (GCs) are widely used in the treatment of hematological malignancies such as multiple myeloma. However, the development of resistance to GCs limits their clinical utility. Response to GCs is dependent on an active glucocorticoid receptor, GR-?, expressed at wild-type levels in the GC-sensitive cell line (MM.1S). GC-resistant derivative cell lines MM.1Re and MM.1RL display significant downregulation of GR-? transcripts. In this study, we report that a luciferase reporter containing the 3'-UTR of GR-? is significantly repressed in MM.1R cells when compared to MM.1S cells, suggesting that one or several microRNAs that are upregulated in MM.1R maybe in part responsible for the downregulation of the GR-? transcript. To examine posttranscriptional mechanisms of GR regulation, we examined miRNAs that have complimentary binding sites in the 3'-UTR of GR-? and found miR-130b, miR-181a, and miR-636 to be differentially expressed between GC-sensitive and GC-resistant MM.1 cell lines. Overexpression of miR-130b in MM.1S cells results in decreased expression of endogenous GR protein and decreased activity of the luciferase reporter. In addition, in MM.1S cells, the downstream GC response of glucocorticoid-induced leucine zipper induction is decreased by the overexpression of miR-130b, and further miR-130b inhibits GC-induced apoptosis and causes resistance to GCs.

SUBMITTER: Tessel MA

PROVIDER: S-EPMC3725966 | biostudies-literature | 2011 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Role for microRNAs in regulating glucocorticoid response and resistance in multiple myeloma.

Tessel Michael A MA Benham Ashley L AL Krett Nancy L NL Rosen Steven T ST Gunaratne Preethi H PH

Hormones & cancer 20110601 3

Glucocorticoids (GCs) are widely used in the treatment of hematological malignancies such as multiple myeloma. However, the development of resistance to GCs limits their clinical utility. Response to GCs is dependent on an active glucocorticoid receptor, GR-α, expressed at wild-type levels in the GC-sensitive cell line (MM.1S). GC-resistant derivative cell lines MM.1Re and MM.1RL display significant downregulation of GR-α transcripts. In this study, we report that a luciferase reporter containin ...[more]

PMID: 21761344

Similar Datasets

Project description:Glucocorticoids (GCs) selectively trigger cell death in the multiple myeloma cell line MM1S which express NR3C1/Glucocorticoid Receptor (GR) protein, but fail to kill MM1R cells which lack GR protein. Given recent demonstrations of altered microRNA profiles in a diverse range of haematological malignancies and drug resistance, we characterized GC inducible mRNA and microRNA transcription profiles in GC sensitive MM1S as compared to GC resistant MM1R cells. Transcriptome analysis revealed that GCs regulate expression of multiple genes involved in cell cycle control, cell organization, cell death and immunological disease in MM1S cells, which remain unaffected in MM1R cells. With respect to microRNAs, mir-150-5p was identified as the most time persistent GC regulated microRNA, out of 5 QPCR validated microRNAs (mir-26b, mir-125a-5p, mir-146-5p, mir-150-5p, and mir-184), which are GC inducible in MM1S but not in MM1R cells. Functional studies further revealed that ectopic transfection of a synthetic mir-150-5p mimics GR dependent gene expression changes involved in cell death and cell proliferation pathways. Remarkably, despite the gene expression changes observed, overexpression of mir-150-5p in absence of GCs did not trigger significant cytotoxicity in MM1S or MM1R cells. This suggests the requirement of additional steps in GC induced cell death, which can not be mimicked by mir-150-5p overexpression alone. Interestingly, a combination of mir-150-5p transfection with low doses GC in MM1S cells was found to sensitize therapy response, whereas opposite effects could be observed with a mir-150-5p specific antagomir. Although mir-150-5p overexpression did not substantially change GR expression levels, it was found that mir-150-5p evokes GR specific effects through indirect mRNA regulation of GR interacting transcription factors and hormone receptors, GR chaperones, as well as various effectors of unfolded protein stress and chemokine signalling. Altogether GC-inducible mir-150-5p adds another level of regulation to GC specific therapeutic responses in multiple myeloma.

Project description:BackgroundMultiple myeloma (MM) is an incurable hematological malignancy. Although proteasome inhibitors and immunomodulators have significantly improved patient outcomes, some patients respond poorly to treatment and almost all patients will relapse. Mechanisms of proteasome inhibitor resistance in multiple myeloma have not been fully elucidated. ZHX2 is a transcription regulator degraded via proteasome and presents both oncogenic or tumor suppressive effect in different cancers, however, it is still unknown that the role of ZHX2 in myeloma. In this study, we aim to demonstrate the effect and mechanism of ZHX2 on proteasome inhibitor resistance in MM.MethodsGSE24080 gene expression profile datasets from Gene Expression Omnibus (GEO) were analyzed to evaluate the relationship between ZHX2 expression level and survival in MM. Expression of ZHX2 in human MM cell lines at baseline and after bortezomib (BTZ) treatment was determined by Western blotting (WB). The proliferation and apoptosis rate of MM cells treated with BTZ after the knockdown of ZHX2 were analyzed by flow cytometry. Nuclear translocation of NF-κB after the knockdown of ZHX2 was evaluated by WB and immunofluorescence, and the expression of NF-κB target genes was measured by real-time quantitative PCR. Co-immunoprecipitation (Co-IP) and WB were used to detect the interaction of ZHX2 with NF-κB.ResultsWe found that higher ZHX2 expression was correlated with poorer clinical outcomes of patients. In addition, ZHX2 expression was relatively higher in RPMI-8226 and MM.1S cell lines and the level of ZHX2 protein was upregulated after BTZ treatment. Knockdown of ZHX2 significantly enhanced the sensitivity of MM cells to BTZ, inhibited nuclear translocation of NF-κB, and reduced mRNA expression of NF-κB target genes. It was also revealed that ZHX2 directly binds to NF-κB.ConclusionOur study showed that ZHX2 can promote proteasome inhibitor resistance in MM cells by regulating the nuclear translocation of NF-κB.

Dataset Information

Role for microRNAs in regulating glucocorticoid response and resistance in multiple myeloma.

Publications

Role for microRNAs in regulating glucocorticoid response and resistance in multiple myeloma.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets