MP84-04 GENOMIC SCREEN IDENTIFIES ACTIONABLE KINASES FOR OBESITY DRIVEN PROSTATE CANCER

Abstract

You have accessJournal of UrologyProstate Cancer: Basic Research & Pathophysiology III1 Apr 2016MP84-04 GENOMIC SCREEN IDENTIFIES ACTIONABLE KINASES FOR OBESITY DRIVEN PROSTATE CANCER Everardo Macias, David Corcoran, Jen-Tsan Chi, and Stephen Freedland Everardo MaciasEverardo Macias More articles by this author , David CorcoranDavid Corcoran More articles by this author , Jen-Tsan ChiJen-Tsan Chi More articles by this author , and Stephen FreedlandStephen Freedland More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2016.02.2228AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Obesity is linked with greater risk of high-grade prostate cancer (PC), recurrence after therapy, metastases, and PC death. Every 5 kg/m2 increased body mass is linked with 20% higher risk of PC death. On the other hand, pre-clinical and human data suggest the excess risk from obesity can be reduced by caloric restriction (CR). However, while CR slows tumor growth, tumors continue to grow. Given only modest responses to CR, tumors must have resistance mechanisms to CR. In addition, adherence to any restrictive diet or lifestyle change is difficult. Thus, it is important to reduce obesity associated risks via complimentary or alternative approaches as well as to identify resistance mechanisms in PC to CR. We hypothesize that aberrant activity of a small subset of kinases promotes PC growth in obese hosts and resistance to caloric restriction. To identify targetable kinases for PC therapy in a host specific manner, we conducted a functional genomic kinome screen. METHODS LAPC-4 cells were inoculated (MOI of 0.3) with a shRNA library of ~5000 lentivirus targeting 513 kinases. 5x106 cells (~1,000 cells per shRNA) were grafted to chronically obese mice. Tumors were established to ~200 mm3 and a portion collected for baseline reference. Remaining mice were randomized to continue on ad lib WD or 25% CR diet. Mice were sacrificed 25 days after randomization. Genome-integrated shRNA inserts from tumoral DNA were amplified using nested barcoded (6 bp) PCR primers. Amplified shRNAs were sequenced using Illumina Hi-Seq 2000 and quantified. We focused on depleted probes with 2-fold less reads in diet arm tumors vs. reference tumors with a p-value <= 0.05. RESULTS Tumor volumes and weights at sacrifice were larger in WD mice compared to 25% CR mice. Of the >5000 shRNAs screened, 99 were significantly (p=0.05) depleted in obese, 103 in CR and 37 in both arms. As expected, Akt, mTOR, Insulin Receptor and IGF-1R were found significantly depleted. Among the depleted hits, we focused on RIOK2 which was significantly depleted (-5.46 log2fold, p= 0.0062) in tumors from obese mice, but not 25% CR mice. RIOK2 expression varies between AR null (DU145) and AR wildtype (LnCaP) PC cells and was induced with synthetic androgen R1881. RIOK2 knockdown with shRNAs shows dramatic cell death in multiples PC cells and RIOK2 positively correlates with Gleason score in a radical prostatectomy TMA. CONCLUSIONS RIOK2 is an AR target gene that may promote PC growth in obese hosts. Our next aim is to validate RIOK2 in obesity driven PC and asses other hits. Altogether, our in vivo screen has yielded host specific actionable targets. © 2016FiguresReferencesRelatedDetails Volume 195Issue 4SApril 2016Page: e1090-e1091 Advertisement Copyright & Permissions© 2016MetricsAuthor Information Everardo Macias More articles by this author David Corcoran More articles by this author Jen-Tsan Chi More articles by this author Stephen Freedland More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...