In prostate cancer, the development of castration resistance is pivotal in progression to aggressive disease. However, understanding of the pathways involved remains incomplete. In this study, we performed a high-throughput genetic screen to identify kinases that enable tumor formation by androgen-dependent prostate epithelial (LHSR-AR) cells under androgen-deprived conditions. In addition to the identification of known mediators of castration resistance, which served to validate the screen, we identified a mitotic-related serine/threonine kinase, NEK6, as a mediator of androgen-independent tumor growth. NEK6 was overexpressed in a subset of human prostate cancers. Silencing NEK6 in castration-resistant cancer cells was sufficient to restore sensitivity to castration in a mouse xenograft model system. Tumors in which castration resistance was conferred by NEK6 were predominantly squamous in histology with no evidence of AR signaling. Gene expression profiling suggested that NEK6 overexpression stimulated cytoskeletal, differentiation and immune signaling pathways and maintained gene expression patterns normal decreased by castration. Phosphoproteome profiling revealed the transcription factor FOXJ2 as a novel NEK6 substrate, with FOXJ2 phosphorylation associated with increased expression of newly identified NEK6 transcriptional targets. Overall, our studies establish NEK6 signaling as a central mechanism mediating castration-resistant prostate cancer.
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Cancer research. 2016 Jan 29 [Epub ahead of print]
Atish D Choudhury, Anna C Schinzel, Maura B Cotter, Rosina T Lis, Katherine Labella, Ying Jie Lock, Francesca Izzo, Isil Guney, Michaela Bowden, Yvonne Y Li, Jinal Patel, Emily Hartman, Steven A Carr, Monica Schenone, Jacob D Jaffe, Philip W Kantoff, Peter S Hammerman, William C Hahn
Medical Oncology, Dana-Farber Cancer Institute., Department of Pathology, Dana-Farber Cancer Institute., Department of Medical Oncology, Dana-Farber Cancer Institute., Proteomics Platform, Broad Institute of MIT and Harvard., Proteomics, Broad Institute of MIT and Harvard., Department of Medicine, Memorial Sloan Kettering Cancer Center., Medical Oncology, Dana-Farber Cancer Institute .