Gene expression changes in human triple negative breast cancer cells with loss of MDM2
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE214101 | GEO | 2023/05/10
REPOSITORIES: GEO
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Project description:RNA-sequencing was performed to gain insight into the mechanism responsible for the apoptosis and cell cycle arrest induced by loss of Mdm2 in p53-null cells. Following CreERT2-mediated deletion of Mdm2 in three p53-null cell types (T cell lymphoma, sarcoma, and fibroblasts), RNA-sequencing was performed. This high-throughput data revealed Mdm2 deletion in p53-null cells upregulated p53/p73 transcriptional target genes known to induce apoptosis and cell cycle arrest.
2017-09-06 | GSE98705 | GEO
Project description:Adult cardiomyocytes (CM) are terminally differentiated cells with minimal regenerative capacity, making cardiac tissue particularly vulnerable to injury. Thus, defining the roadblocks responsible for adult CM cell cycle arrest lies at the core of developing therapies to regenerate myocyte loss following injurious events such as myocardial infarction. We have previously shown that inactivating the p53/Mdm2 tumor suppressor circuitry, specifically in the heart (using the Cre-loxP recombination system of bacteriophage P1), can allow differentiated CMs to regain proliferative capacity, through an upregulation of factors involved in cell cycle re-entry. These factors are repressed in quiescent CMs, in part through the action of microRNAs (miRNAs). Notably, knockout of either p53 or Mdm2 individually was insufficient to promote CM proliferation. Therefore, we hypothesized that inactivation of p53/Mdm2-regulated miRNAs could promote the expression of cell cycle activators and induce proliferation of adult murine CMs. To identify miRNAs regulated by both p53 and Mdm2, total miRNA expression profiles from cardiac specific p53/Mdm2 double knockout (DKO) mouse hearts were compared with those from cardiac-specific single knockouts (p53KO and Mdm2KO), and vehicle-injected controls using the Nanostring nCounter mouse miRNA expression assay. This revealed a profile of 11 significantly downregulated miRNAs in the proliferative DKO hearts (versus vehicle-injected control), that were enriched for mRNA targets involved in cell cycle regulation. In vitro studies have demonstrated that knockdown of these 11 miRNAs in neonatal rat cardiomyocytes can increase the occurrence of cytokinetic events. Ultimately, we aim to inject antagomirs targeting these miRNAs into animals post-myocardial infarction to determine the effect of p53/Mdm2-regulated miRNAs on heart function and CM proliferation in vivo.
2017-03-22 | E-MTAB-5531 | biostudies-arrayexpress
Project description:The MDM2 oncoprotein is an essential component of the p53 pathway. Although MDM2 has been widely described as a major negative regulator of the p53 tumor suppressor, growing evidences support the notion that Mdm2 functions are also mediated through p53 independent mechanisms. We found that MDM2 is recruited on chromatin. By ChIP-Seq (using MDM2 antibody) of H1299 cells exhibiting MDM2 recruitment on chromatin, we identified at the whole genome level MDM2 binding sites. Both input and IPped-DNA were exhaustively sequenced and mapped on human genome
2016-06-09 | GSE64439 | GEO
Project description:Malignant rhabdoid tumors (MRT) are highly aggressive pediatric cancers that respond poorly to current therapies. We screened several MRT cell lines each with large-scale RNAi, CRISPR-Cas9, and small-molecule libraries to identify potential drug targets specific for these cancers. We discovered MDM2 and MDM4, the canonical negative regulators of p53, as significant vulnerabilities. Using two compounds currently in clinical development, idasanutlin and ATSP-7041, we show that MRT cells are more sensitive than other p53 wild-type cancer cell lines to MDM2 and dual MDM2/4 inhibition in vitro. These compounds cause significant upregulation of the p53 pathway in MRT cells, and sensitivity is ablated by CRISPR-Cas9-mediated inactivation of TP53. We show that loss of SMARCB1, a subunit of the SWI/SNF (BAF) complex mutated in nearly all MRT, sensitizes cells to MDM2 and MDM2/4 inhibition by enhancing p53-mediated apoptosis. Both MDM2 and MDM2/4 inhibition slowed MRT xenograft growth in vivo, with a five-day idasanutlin pulse causing marked regression of all xenografts including durable complete responses in 50% of mice. Together, these studies identify a genetic connection between mutations in the SWI/SNF chromatin-remodeling complex and the tumor suppressor gene p53, and provide preclinical evidence to support the targeting of MDM2 and MDM4 in this often-fatal pediatric cancer.
2019-02-04 | GSE124508 | GEO
Project description:Gene expression changes in human triple negative breast cancer cells with loss of MDM2
| PRJNA883954 | ENA
Project description:CDK4 inhibitors have reached clinical approval for cancer therapy. In parallel, the p53 antagonist Mdm2 remains an attractive target for anti-cancer therapy, including numerous clinical studies. The genes encoding Mdm2 and CDK4 are frequently co-amplified in human malignancies, most notably in liposarcomas, suggesting their combined targeting for therapy. Here we show, however, that small compounds that inhibit Mdm2 and CDK4 antagonize each other rather than synergize in their cytotoxicity towards sarcoma cells. CDK4 inhibition attenuates the induction of p53-responsive genes upon Mdm2 inhibition, and similar results were obtained when depleting Mdm2 and/or CDK4 with siRNA. CDK4 inhibitors also interfered with p53 activity in response to DNA damage. CDK4 inhibition did not reduce p53 binding or histone acetylation to promoters, but rather attenuated the subsequent recruitment of RNA polymerase II. The complexes of p53 and Mdm2, as well as CDK4 and Cyclin D1, physically associated with each other. Upon combined inhibition of Mdm2 and CDK4/6, the interaction of this complex was impaired. Thus, the CDK4-Cyclin D1 complex plays a key role in enabling the transcription of p53 target genes. Taken together, our results raise caution regarding the combination of CDK4 inhibitors with Mdm2 antagonists or conventional DNA-damaging chemotherapeutics in the clinics. Moreover, they suggest a hitherto unknown role for CDK4-cyclin D1 complex in sustaining p53 activity, possibly focusing p53-mediated transcription on actively proliferating cells.
2018-09-20 | GSE113369 | GEO
Project description:In most lymphomas, p53 signaling pathway is inactivated by various mechanisms independent to p53 gene mutations or deletions. In many cases, p53 function is largely regulated by alterations in the protein abundance levels by the action of E3 ubiquitin-protein ligase MDM2, targeting p53 to proteasome-mediated degradation. In the present study, an integrating transcriptomics and pro-teomics analysis was employed to investigate the effect of p53 activation by a small-molecule MDM2-antagonist, nutlin 3a, on three lymphoma cell models following p53 activation. Our analy-sis revealed a system-wide nutlin 3a-associated effect in all examined lymphoma types, identifying in total of 4037 differentially affected proteins involved in a plethora of pathways, with significant heterogeneity among lymphomas. Our findings include known p53-targets and novel p53 activa-tion effects, involving transcription, translation, or degradation of protein components of path-ways, such as a decrease in key members of PI3K/mTOR pathway, heat-shock response, and gly-colysis, and an increase in key members of oxidative phoshosphorylation, autophagy and mito-chondrial translation. Combined inhibition of HSP90 or PI3K/mTOR pathway with nutlin 3a-mediated p53-activation enhanced the apoptotic effects suggesting a promising strategy against human lymphomas. Integrated omic profiling after p53 activation offered novel insights on the regulatory role specific proteins and pathways may have in lymphomagenesis.
2023-07-30 | PXD009290 | Pride
Project description:Circular RNAs (circRNAs) are a class of noncoding RNAs produced by a non-canonical form of alternative splicing called back-splicing. To investigate a potential role of circRNAs in the p53 pathway, we analyzed RNA-seq data from colorectal cancer cell lines (HCT116, RKO and SW48) in the presence or absence of DNA damage. Surprisingly, unlike the strong p53-dependent induction of hundreds of p53-induced mRNAs, only a few circRNAs were induced from the p53-induced genes. Circ-MDM2, an annotated circRNA from the MDM2 locus, was one of the handful of circRNAs that originated from a p53-induced gene. Given the central role of MDM2 in suppressing p53 protein levels and p53 activity, we investigated the function of circ-MDM2. Knocking down circ-MDM2 with siRNAs that targeted the circ-MDM2 junction and had no effect on linear MDM2 mRNA, resulted in increased basal p53 levels and growth defects in vitro and in vivo. Consistent with these results, transcriptome profiling showed increased expression of several direct p53 targets, reduced Rb phosphorylation and defects in G1-S progression upon silencing circ-MDM2. Our results reveal the role of a novel circRNA by which the MDM2 locus suppresses p53 levels and cell cycle progression.
2020-03-04 | GSE138016 | GEO
Project description:Amplification of the ubiquitin ligase MDM2 is a common mechanism of P53 inactivation across human tumors. Here we investigated the impact of supraphysiologic MDM2 expression on chromatin topology, gene expression and cellular phenotypes in liposarcoma tumors and models. We identified three independent gene regulatory circuits that predominate in aggressive, dedifferentiated tumors. RUNX and AP-1 family transcription factors bind a shared set of enhancers associated with mesenchymal lineage genes that underlie the developmental state of these tumors. P53 and MDM2 co-occupy enhancers and promoters associated with P53 pathways. When highly expressed, MDM2 also binds an additional set of P53-independent promoters that engage in multi-way physical interactions and regulate genes involved in cell division, RNA splicing, translation and stress responses. We find that liposarcoma cells with low to moderate MDM2 levels are sensitive to P53 inhibitors and their combination with pro-apoptotic agents, but that cells with very high-level MDM2 amplification and expression resist treatment. Hence, heterogeneity of MDM2 expression between and within tumors may compromise therapeutic regimens. In conclusion, we distinguished P53-dependent and P53-independent circuits in MDM2 copy number amplified tumors whose interplay has implications for targeted therapy.
2023-04-10 | GSE213300 | GEO
Project description:The Mdm2 oncoprotein ubiquitinates and antagonizes p53 but may also carry out p53-independent functions. Here we report that Mdm2 is required for the efficient generation of induced pluripotent stem cells (iPSCs) from murine embryonic fibroblasts, in the absence of p53. Similarly, Mdm2 depletion in the context of p53 deficiency also promoted the differentiation of human mesenchymal stem cells and diminished clonogenic survival of cancer cells. Most of the Mdm2-controlled genes also responded to the inactivation of the Polycomb Repressor Complex 2 (PRC2) and its catalytic component EZH2. Mdm2 physically associated with EZH2 on chromatin, enhancing the trimethylation of Histone 3 at lysine 27 and the ubiquitination of Histone 2A at lysine 119 (H2AK119) at its target genes. Removing Mdm2 simultaneously with the H2AK119 E3 ligase Ring1B/RNF2 further induced these genes and synthetically arrested cell proliferation. In conclusion, Mdm2 supports the Polycomb-mediated repression of lineage specific genes independent of p53. Expression profiling by high throughput sequencing of p53 ko MEFs, p53Mdm2 ko MEFs, p53ko Mdm2 C462A ki MEFs.
2015-12-31 | E-GEOD-73176 | biostudies-arrayexpress