Abstract 4971: Splicing factor kinase regulates metastatic dissemination of human prostate cancer

Abstract

Abstract Metastasis causes the vast majority of cancer-associated deaths. Despite its clinical significance, the molecular mechanisms that regulate this multi-step process are poorly understood. To successfully disseminate a cancer cell must escape the primary tumor, travel to a distant site, arrest, enter the stroma and grow in a new microenvironment. The presence of circulating tumor cells in patients with metastatic disease and experimental animals with metastatic cancers suggests that tumor invasion is a critical, rate-limiting step in the metastatic process. To identify the key molecular determinants that regulate invasive metastatic lesion formation we performed the first whole-genome, in vivo RNAi screen in an avian embryo model using advanced intravital imaging techniques. We identified numerous novel regulators of cancer cell invasion, including JL1, a splicing factor kinase. In secondary assays, we demonstrated that JL1-depletion inhibits migration of several human cancer cell lines with no effect on proliferation or survival. Furthermore, JL1-deficient human cancer cells display diminished metastatic potential in chicken embryo and mouse models of metastasis. Cancer microarray database mining shows that JL1 gene expression is strongly associated with indicators of poor clinical outcome in prostate cancer, including pathological Gleason score and metastasis. To experimentally determine JL1 association with advanced disease we performed histological examinations of prostate cancer tissue and determined that JL1 staining strongly correlates with prostate cancer progression. JL1 kinase regulates alternative splicing of numerous cellular transcripts in response to stress and growth signals. To examine the molecular mechanism behind JL1 regulation of cancer cell metastasis, we performed exon level microarray analysis on JL1-depleted cancer cell lines. Subsequent interactome analysis identified an enrichment of key regulatory proteins in pro-metastatic networks. Therefore, we hypothesize that abrogated JL1 activity directly promotes prostate cancer cell migration and invasion. In summary, JL1 is a novel regulator of cancer cell metastasis that represents a potential pathological marker for prostate cancer progression, and novel drug target to block invasion and metastasis. Citation Format: David J. Bond, Konstantin Stoletov, Hon Sing Leong, Emma Woolner, Shuhong Liu, Tarek Bismar, Andries Zijlstra, John D. Lewis. Splicing factor kinase regulates metastatic dissemination of human prostate cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4971. doi:10.1158/1538-7445.AM2014-4971