Dataset Information

IKBKE activity enhances AR levels in advanced prostate cancer via modulation of the Hippo pathway.

ABSTRACT: Resistance to androgen receptor (AR) targeting therapeutics in prostate cancer (PC) is a significant clinical problem. Mechanisms by which this is accomplished include AR amplification and expression of AR splice variants, demonstrating that AR remains a key therapeutic target in advanced disease. For the first time we show that IKBKE drives AR signalling in advanced PC. Significant inhibition of AR regulated gene expression was observed upon siRNA-mediated IKBKE depletion or pharmacological inhibition due to inhibited AR gene expression in multiple cell line models including a LNCaP derivative cell line resistant to the anti-androgen, enzalutamide (LNCaP-EnzR). Phenotypically, this resulted in significant inhibition of proliferation, migration and colony forming ability suggesting that targeting IKBKE could circumvent resistance to AR targeting therapies. Indeed, pharmacological inhibition in the CWR22Rv1 xenograft mouse model reduced tumour size and enhanced survival. Critically, this was validated in patient-derived explants where enzymatic inactivation of IKBKE reduced cell proliferation and AR expression. Mechanistically, we provide evidence that IKBKE regulates AR levels via Hippo pathway inhibition to reduce c-MYC levels at cis-regulatory elements within the AR gene. Thus, IKBKE is a therapeutic target in advanced PC suggesting repurposing of clinically tested IKBKE inhibitors could be beneficial to castrate resistant PC patients.

SUBMITTER: Bainbridge A

PROVIDER: S-EPMC7261174 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

IKBKE activity enhances AR levels in advanced prostate cancer via modulation of the Hippo pathway.

Bainbridge Alex A Walker Scott S Smith Joseph J Patterson Kathryn K Dutt Aparna A Ng Yi Min YM Thomas Huw D HD Wilson Laura L McCullough Benjamin B Jones Dominic D Maan Arussa A Banks Peter P McCracken Stuart R SR Gaughan Luke L Robson Craig N CN Coffey Kelly K

Nucleic acids research 20200601 10

Resistance to androgen receptor (AR) targeting therapeutics in prostate cancer (PC) is a significant clinical problem. Mechanisms by which this is accomplished include AR amplification and expression of AR splice variants, demonstrating that AR remains a key therapeutic target in advanced disease. For the first time we show that IKBKE drives AR signalling in advanced PC. Significant inhibition of AR regulated gene expression was observed upon siRNA-mediated IKBKE depletion or pharmacological inh ...[more]

PMID: 32324216

Similar Datasets

Project description:BackgroundOsteosarcoma (OS) is the most prevalent primary bone malignancy affecting adolescents, yet the emergence of chemoradiotherapeutic resistance has limited efforts to cure affected patients to date. Pyropheophorbide-α methyl ester-mediated photodynamic therapy (MPPa-PDT) is a recently developed, minimally invasive treatment for OS that is similarly constrained by such therapeutic resistance. This study sought to explore the mechanistic basis for RhoA-activated YAP1 (YAP)-mediated resistance in OS.MethodsThe relationship between YAP expression levels and patient prognosis was analyzed, and YAP levels in OS cell lines were quantified. Immunofluorescent staining was used to assess YAP nuclear translocation. OS cell lines (HOS and MG63) in which RhoA and YAP were knocked down or overexpressed were generated using lentiviral vectors. CCK-8 assays were used to examine OS cell viability, while the apoptotic death of these cells was monitored via Hoechst staining, Western blotting, and flow cytometry. Tumor-bearing nude mice were additionally used to assess the relationship between lentivirus-mediated alterations in RhoA expression and MPPa-PDT treatment outcomes. TUNEL and immunohistochemical staining approaches were leveraged to assess apoptotic cell death in tissue samples.ResultsOS patients exhibited higher levels of YAP expression, and these were correlated with a poor prognosis. MPPa-PDT induced apoptosis in OS cells, and such MPPa-PDT-induced apoptosis was enhanced following YAP knockdown whereas it was suppressed by YAP overexpression. RhoA and YAP expression levels were positively correlated in OS patients, and both active and total RhoA protein levels rose in OS cells following MPPa-PDT treatment. When RhoA was knocked down, levels of unphosphorylated YAP and downstream target genes were significantly reduced, while RhoA/ROCK2/LIMK2 pathway phosphorylation was suppressed, whereas RhoA overexpression resulted in the opposite phenotype. MPPa-PDT treatment was linked to an increase in HMGCR protein levels, and the inhibition of RhoA or HMGCR was sufficient to suppress RhoA activity and to decrease the protein levels of YAP and its downstream targets. Mevalonate administration partially reversed these reductions in the expression of YAP and YAP target genes. RhoA knockdown significantly enhanced the apoptotic death of OS cells in vitro and in vivo following MPPa-PDT treatment, whereas RhoA overexpression had the opposite effect.ConclusionsThese results suggest that the mevalonate pathway activates RhoA, which in turn activates YAP and promotes OS cell resistance to MPPa-PDT therapy. Targeting the RhoA/ROCK2/LIMK2/YAP pathway can significantly improve the efficacy of MPPa-PDT treatment for OS.

Project description:Regulation of hepatocyte proliferation and liver morphology is of critical importance to tissue and whole-body homeostasis. However, the molecular mechanisms that underlie this complex process are incompletely understood. Here we describe a novel role for the ubiquitin ligase BRAP in regulation of hepatocyte morphology and turnover via regulation of MST2, a protein kinase in the Hippo pathway. The Hippo pathway has been implicated in control of liver morphology, inflammation and fibrosis. We demonstrate here that liver-specific ablation of Brap in mice results in gross and cellular morphological alterations of the liver. Brap-deficient livers exhibit increased hepatocyte proliferation, cell death, and inflammation. We show that loss of BRAP protein alters Hippo pathway signaling, causing a reduction in phosphorylation of YAP and increased expression of YAP target genes, including those regulating cell growth and interactions with the extracellular environment. Finally, increased Hippo signaling in Brap knockout mice alters the pattern of liver lipid accumulation in dietary models of obesity. These studies identify a role for BRAP as a modulator of the hepatic Hippo pathway with relevance to human liver disease. tissue and whole-body homeostasis. However, the molecular mechanisms that underlie this complex process are incompletely understood. Here we describe a novel role for the ubiquitin ligase BRAP in regulation of hepatocyte morphology and turnover via regulation of MST2, a protein kinase in the Hippo pathway. The Hippo pathway has been implicated in control of liver morphology, inflammation and fibrosis. We demonstrate here that liver-specific ablation of Brap in mice results in gross and cellular morphological alterations of the liver. Brap-deficient livers exhibit increased hepatocyte proliferation, cell death, and inflammation. We show that loss of BRAP protein alters Hippo pathway signaling, causing a reduction in phosphorylation of YAP and increased expression of YAP target genes, including those regulating cell growth and interactions with the extracellular environment. Finally, increased Hippo signaling in Brap knockout mice alters the pattern of liver lipid accumulation in dietary models of obesity. These studies identify a role for BRAP as a modulator of the hepatic Hippo pathway with relevance to human liver disease.

Dataset Information

IKBKE activity enhances AR levels in advanced prostate cancer via modulation of the Hippo pathway.

Publications

IKBKE activity enhances AR levels in advanced prostate cancer via modulation of the Hippo pathway.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets