Abstract B07: NUAK2 inhibition for prostate cancer

Abstract

Obesity is a US and global epidemic that exacerbates various cancers including prostate cancer (PC). A recent meta-analysis of men with PC found a 20% increased risk of PC-specific mortality for each 5 kg/m2 increase in BMI. To identify ways to exploit this, we performed an in vivo screen to identify kinases that were causally involved in tumor/growth in obese mice. This resulted in the identification of the AMPK-related kinase SNARK a.k.a NUAK2, a YAP1 target gene and positive feedback regulator by inhibition LATS1 kinase. To identify obesity essential kinases LAPC-4 cells were inoculated with an shRNA library of ~5,000 lentivirus targeting 513 kinases. 5 × 106 cells were grafted to chronically obese mice. Tumors were established to ~200 mm3 and a portion collected for reference. Remaining mice were randomized to continue on ad lib WD or 25% CR diet. Genome-integrated shRNA inserts were amplified using nested barcoded primers and sequenced using Illumina Hi-Seq 2000 and quantified. NAUK2 shRNAs (3 of 10) were significantly depleted in LAPC4 xenograft tumors from mice on a Western diet (WD), but not tumors from mice on an isocaloric 25% calorie-restricted (CR) diet. Analysis of NUAK2 gene expression in human PCs shows NUAK2 expression is higher in PC tissue vs. normal benign. In addition, Cox regression analysis showed that NUAK2 is associated with a 3-fold increased chance of developing metastasis disease in high NUAK2 group. Proteomic data from metastatic PC rapid autopsy biopsies shows NUAK2 phospho-target LATS1 Ser464 is higher in metastatic PCs vs. benign localized prostatic tissues. Western blot analysis of PC cell lines shows NUAK2 is elevated in comparison to primary prostate epithelial cells. To test if NUAK2 is an actionable target in PC cells, we utilized two narrow-spectrum kinase inhibitors from the literature, WZ4003 and HTH-02-006. Pharmacologic inhibition of NUAK2 slows 2D PC cell growth and 3D PC spheroid growth of various PC cell lines with an IC50 range between 1-10 uM, with HTH-02-006 being the more potent. In addition, NUAK2 kinase inhibition with WZ4003 and HTH-02-006 significantly slowed migration and Matrigel invasion of PC3 and DU145 cells. To test if NUAK2 is associated with obesity-enhanced PC progression, we tested NUAK2 inhibition in combination with palmitic acid supplementation. Our preliminary studies show that pharmacologic inhibition of NUAK2 sensitized PC cells to fatty acid-induced cell death. In conclusion, our in vivo shRNA screen identified NUAK2 as an essential kinase for tumors grown in obese mice. NUAK2 expression correlates with worse outcomes in PC and NUAK2 kinase activity is elevated in metastatic vs. localized PCs. Our preliminary data show that pharmacologic inhibition of NUAK2 slows PC cell growth and migration/invasion. Lastly, our preliminary studies show that NUAK2 may lower the threshold for fatty acid-induced toxicity. Together, these preliminary data suggest NUAK2 is a relevant actionable target in PC and may synergize with obese host physiology to slow PC tumor growth. Citation Format: Weiwei Fu, Megan Zhao, Amelia Schirmer, Erick J. Maravilla, Junhee Yoon, Sungyong You, Stephen J. Freedland, Everardo Macias. NUAK2 inhibition for prostate cancer [abstract]. In: Proceedings of the AACR Special Conference on the Hippo Pathway: Signaling, Cancer, and Beyond; 2019 May 8-11; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(8_Suppl):Abstract nr B07.