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Choline Kinase Alpha as an Androgen Receptor Chaperone and Prostate Cancer Therapeutic Target.

Published version
Peer-reviewed

Repository DOI


Type

Article

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Authors

Asim, Mohammad 
Massie, Charles E 
Orafidiya, Folake 
Pértega-Gomes, Nelma 
Warren, Anne Y 

Abstract

BACKGROUND: The androgen receptor (AR) is a major drug target in prostate cancer (PCa). We profiled the AR-regulated kinome to identify clinically relevant and druggable effectors of AR signaling. METHODS: Using genome-wide approaches, we interrogated all AR regulated kinases. Among these, choline kinase alpha (CHKA) expression was evaluated in benign (n = 195), prostatic intraepithelial neoplasia (PIN) (n = 153) and prostate cancer (PCa) lesions (n = 359). We interrogated how CHKA regulates AR signaling using biochemical assays and investigated androgen regulation of CHKA expression in men with PCa, both untreated (n = 20) and treated with an androgen biosynthesis inhibitor degarelix (n = 27). We studied the effect of CHKA inhibition on the PCa transcriptome using RNA sequencing and tested the effect of CHKA inhibition on cell growth, clonogenic survival and invasion. Tumor xenografts (n = 6 per group) were generated in mice using genetically engineered prostate cancer cells with inducible CHKA knockdown. Data were analyzed with χ(2) tests, Cox regression analysis, and Kaplan-Meier methods. All statistical tests were two-sided. RESULTS: CHKA expression was shown to be androgen regulated in cell lines, xenografts, and human tissue (log fold change from 6.75 to 6.59, P = .002) and was positively associated with tumor stage. CHKA binds directly to the ligand-binding domain (LBD) of AR, enhancing its stability. As such, CHKA is the first kinase identified as an AR chaperone. Inhibition of CHKA repressed the AR transcriptional program including pathways enriched for regulation of protein folding, decreased AR protein levels, and inhibited the growth of PCa cell lines, human PCa explants, and tumor xenografts. CONCLUSIONS: CHKA can act as an AR chaperone, providing, to our knowledge, the first evidence for kinases as molecular chaperones, making CHKA both a marker of tumor progression and a potential therapeutic target for PCa.

Description

Keywords

Aged, Animals, Antineoplastic Agents, Biomarkers, Tumor, Choline Kinase, Enzyme Inhibitors, Gene Expression Regulation, Neoplastic, Humans, Kaplan-Meier Estimate, Male, Mice, Mice, Inbred NOD, Mice, SCID, Middle Aged, Molecular Chaperones, Molecular Targeted Therapy, Neoplasm Grading, Neoplasm Staging, Proportional Hazards Models, Prostatectomy, Prostatic Neoplasms, Receptors, Androgen, Sequence Analysis, DNA, Signal Transduction, Xenograft Model Antitumor Assays

Journal Title

Journal of the National Cancer Institute

Conference Name

Journal ISSN

0027-8874
1460-2105

Volume Title

108

Publisher

Oxford University Press
Sponsorship
Cancer Research UK (CB4110)
Cancer Research UK (C14303/A17197)
Cancer Research UK (20406)
Cancer Research UK (11562)
Cancer Research UK (20411)
This work was supported by a Cancer Research UK program grant (to DEN) and also by the US Department of Defense (Prostate Cancer Research Program Transformative Impact Award, grant ID W81XWH-13-2-0093; WDT and SMD), PCFA/Cancer Australia/Movember (grant IDs 1012337 and 1043482; WDT and LAS), Cancer Australia (grant ID 1043497; WDT and JC) and The Ray and Shirl Norman Cancer Research Trust (WDT and LAS). The Dame Roma Mitchell Cancer Research Laboratories were supported by an establishment grant from the PCFA (ID 2011/0452). FO was supported by a PhD project grant from Prostate Cancer UK (S10-10). LAS is supported by a Young Investigator Award from the Prostate Cancer Foundation (the Foundation 14 award).