GRB10 sustains AR activity by interacting with PP2A in prostate cancer cells
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ABSTRACT:
PROVIDER: PRJNA626663 | ENA |
REPOSITORIES: ENA
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Project description:Prostate cancer (PCa) progression is driven by androgen receptor (AR) signaling. Unfortunately, androgen-deprivation therapy and the use of even more potent AR pathway inhibitors (ARPI) cannot bring about a cure. ARPI resistance (i.e. castration-resistant PCa, CRPC) will inevitably develop. Previously, we demonstrated that GRB10 is an AR transcriptionally-repressed gene that functionally contributes to CRPC development and ARPI resistance. GRB10 expression is elevated prior to CRPC development in our patient-derived xenograft models and is significantly upregulated in clinical CRPC samples. Here, we analyzed transcriptomic data from GRB10 knockdown in PCa cells and found that AR signaling is downregulated. While the mRNA expression of AR target genes decreased upon GRB10 knockdown, AR expression was not affected at the mRNA or protein level. We further found that phosphorylation of AR serine 81 (S81), which is critical for AR transcriptional activity, is decreased by GRB10 knockdown and increased by its overexpression. Luciferase assay using GRB10-knockdown cells also indicated reduced AR activity. Immunoprecipitation coupled with mass spectrometry revealed an interaction between GRB10 and the PP2A complex, which is a known phosphatase of AR. Further validations and analyses showed that GRB10 directly binds to the PP2Ac catalytic subunit with its PH domain. Mechanistically, GRB10 knockdown increased PP2Ac protein stability, which in turn decreased AR S81 phosphorylation and reduced AR activity. Our findings indicate a reciprocal feedback between GRB10 and AR signaling, implying the importance of GRB10 in PCa progression.
2020-09-30 | GSE148983 | GEO
Project description:We evaluated the effects of suppressing MAP4K4 on transcriptome and YAP1 pathway based on the observation that partial suppression of MAP4K4 leads to transformation through activation of YAP1. Mutations and deletions involving subunits of the serine-threonine phosphatase PP2A occur in a broad range of human cancers, and partial loss of PP2A function contributes to cell transformation. In particular, displacement of regulatory B subunits by the viral oncoprotein SV40 small-t antigen (ST) or mutation or deletion of PP2A subunits alters the abundance and types of PP2A complexes in cells and induces cell transformation in human cells. Here we show that ST not only displaces common PP2A B subunits but also promotes PP2A A-C subunit interactions with a set of alternative B subunits (B’’’, striatins) that are components of the Striatin-interacting phosphatase and kinase (STRIPAK) complex. We found that members of the STRIPAK complex are required for ST-PP2A induced cell transformation. PP2A interacts with and dephosphorylates the STRIPAK-associated kinase MAP4K4, which induces cell transformation in part through the regulation of the Hippo pathway effector YAP1. These observations identify an unanticipated role of MAP4K4 in transformation and show that the STRIPAK complex plays a key role in defining PP2A specificity and activity.
2019-12-01 | GSE118272 | GEO
Project description:In castration-resistant prostate cancer (CRPC), clinical response to androgen receptor (AR) antagonists is limited mainly due to AR-variants expression and restored AR signaling. The metabolite spermine is most abundant in prostate and it decreases as prostate cancer progresses, but its functions remain poorly understood. Here, we show spermine inhibits full-length androgen receptor (AR-FL) and androgen receptor splice variant 7 (AR-V7) signaling and suppresses CRPC cell proliferation by directly binding and inhibiting protein arginine methyltransferase PRMT1. Spermine reduces H4R3me2a modification at the AR locus and suppresses AR binding as well as H3K27ac modification levels at AR target genes. Spermine supplementation restrains CRPC growth in vivo. PRMT1 inhibition also suppresses AR-FL and AR-V7 signaling and reduces CRPC growth. Collectively, we demonstrate spermine as an anticancer metabolite by inhibiting PRMT1 to transcriptionally inhibit AR-FL and AR-V7 signaling in CRPC, and we indicate spermine and PRMT1 inhibition as powerful strategies overcoming limitations of current AR-based therapies in CRPC.
2023-10-11 | MTBLS8034 | MetaboLights
Project description:The receptor tyrosine kinase-like orphan receptor 1 (ROR1) regulates caveolae formation and caveolae-dependent endocytosis by interacting with caveolae components, which in turn sustains pro-survival signaling toward AKT from multiple RTKs, including EGFR, and MET. We report here a novel function of ROR1 as a scaffold for HRS and STAM1, two essential components of ESCRT-0.
2021-05-27 | PXD020931 | JPOST Repository
Project description:Arctigenin (ATG) is a major component of Fructus Arctii, which as a traditional herbal remedy reduced proteinuria in diabetic patients. However, whether ATG specifically provided renoprotection in DKD was not known. Here we report that ATG administration is sufficient to attenuate proteinuria and podocyte injury in mouse models of diabetes. Transcriptomic analysis of diabetic mouse glomeruli showed that cell adhesion and inflammation are two key pathways affected by ATG treatment, and mass spectrometry analysis identified protein phosphatase 2A (PP2A) as one of the top ATG-interacting proteins in renal cells. Enhanced PP2A activity by ATG reduces p65 NF-κB-mediated inflammatory response and high glucose-induced migration in cultured podocytes via its interaction with Drebrin-1. Importantly, podocyte-specific Pp2a deletion in mice exacerbates DKD injury and abrogates the ATG-mediated renoprotection. Collectively, our results clearly demonstrate a renoprotective mechanism of ATG via PP2A activation and establish PP2A as a potential target for DKD progression.
2019-07-17 | GSE134327 | GEO
Project description:Phosphatase PP2A expression level is positively correlated to the clinical severity of systemic lupus erythematosus (SLE) and IL17A cytokine overproduction, indicating a potential role of PP2A in controlling TH17 differentiation and inflammation. By generating a mouse strain with the ablation of the catalytic subunit α of PP2A in peripheral mature T cells (PP2A cKO), we provide evidence here that PP2A complex is essential in TH17 differentiation. Hence, PP2A cKO mice exhibited a selective reduction of TH17 cell numbers and an attenuated disease severity in an experimental autoimmune encephalomyelitis (EAE) model. Importantly, PP2A deficiency ablated c-terminal phosphorylation of SMAD2 whereas increased c-terminal phosphorylation of SMAD3. Through direct binding to and regulating the activity of RORγt, the phosphorylational changes of these R-SMADs subsequently reduced Il17a transcription. Finally, PP2A inhibitors recapitulated the phenotype of PP2A cKO mice, i.e., inhibiting TH17 differentiation and protecting mice from EAE. Together, the current study proves that phosphatase PP2A is essential for TH17 differentiation, and inhibition of PP2A could be a possible therapeutic approach for the controlling of TH17-driven autoimmune diseases.
2018-09-13 | GSE119836 | GEO
Project description:Activation and transcriptional reprograming of AR in advanced prostate cancer frequently overlaps with the loss of two tumor suppressors, INPP4B and PTEN, which are highly expressed in human and mouse prostate epithelium. While regulation of AR signaling by PTEN has been described by multiple groups, it is not known whether the loss of INPP4B affects AR activity. Using prostate cancer cell lines we showed that INPP4B regulates AR transcriptional activity and oncogenic signaling pathways Akt and PKC. Analysis of gene expression in prostate cancer patient cohorts showed a positive correlation between INPP4B expression and both AR mRNA levels and AR transcriptional output. Using an Inpp4b-/- mouse model, we demonstrated that INPP4B suppresses Akt and PKC signaling pathways and modulates AR transcriptional activity in normal mouse prostate. It has been previously shown that the high fat diet activates Akt pathway in mouse prostate. We showed that the loss of INPP4B further increases Akt phosphorylation in dorsolateral and ventral lobes of mice fed with the high fat diet. Remarkably, PTEN protein levels and phosphorylation of S380 were the same in Inpp4b-/- and WT males, suggesting that observed changes were due exclusively to the loss of INPP4B. Our data show that INPP4B modulates AR activity in normal prostate and its loss contributes to the AR-dependent transcriptional profile in prostate cancer.
2021-03-12 | GSE111725 | GEO
Project description:Androgen receptor (AR) is a main driver for castration-resistant prostate cancer (CRPC). c-Myc is an oncogene underlying prostate tumorigenesis. Here we find that the deubiquitinase USP11 targets both AR and c-Myc in prostate cancer. USP11 expression was upregulated in metastatic prostate cancer and CRPC. USP11 knockdown significantly inhibited prostate cancer cell growth. Our RNA-seq studies revealed AR and c-Myc as the top transcription factors altered after USP11 knockdown. ChIP-seq analysis showed that either USP11 knockdown or replacement of endogenous USP11 with a catalytic-inactive USP11 mutant significantly decreased chromatin binding by AR and c-Myc. We find that USP11 employs two mechanisms to upregulate AR and c-Myc levels: namely, deubiquitination of AR and c-Myc proteins to increase their stability; deubiquitination of H2A-K119Ub, a repressive histone mark, on promoters of AR and c-Myc genes to increase their transcription. AR and c-Myc re-expression in USP11-knockdown prostate cancer cells partly rescued cell growth defects. Thus, our studies reveal a tumor-promoting role for USP11 in aggressive prostate cancer through upregulation of AR and c-Myc activities and support USP11 as a potential target against prostate cancer.
2024-07-13 | GSE268252 | GEO
Project description:Androgen receptor (AR) is a main driver for castration-resistant prostate cancer (CRPC). c-Myc is an oncogene underlying prostate tumorigenesis. Here we find that the deubiquitinase USP11 targets both AR and c-Myc in prostate cancer. USP11 expression was upregulated in metastatic prostate cancer and CRPC. USP11 knockdown significantly inhibited prostate cancer cell growth. Our RNA-seq studies revealed AR and c-Myc as the top transcription factors altered after USP11 knockdown. ChIP-seq analysis showed that either USP11 knockdown or replacement of endogenous USP11 with a catalytic-inactive USP11 mutant significantly decreased chromatin binding by AR and c-Myc. We find that USP11 employs two mechanisms to upregulate AR and c-Myc levels: namely, deubiquitination of AR and c-Myc proteins to increase their stability; deubiquitination of H2A-K119Ub, a repressive histone mark, on promoters of AR and c-Myc genes to increase their transcription. AR and c-Myc re-expression in USP11-knockdown prostate cancer cells partly rescued cell growth defects. Thus, our studies reveal a tumor-promoting role for USP11 in aggressive prostate cancer through upregulation of AR and c-Myc activities and support USP11 as a potential target against prostate cancer.
2024-07-13 | GSE268124 | GEO