Abstract IA004: Identification of potential new therapeutic targets in kidney cancer

Abstract

Abstract VHL is the most important tumor suppressor in clear cell renal cell carcinoma (ccRCC). In the majority of ccRCC, as a result of VHL loss, HIF2a stabilization is sufficient and necessary for promoting ccRCC tumor growth. Despite the development of HIF2a specific inhibitors, the intrinsic and extrinsic resistance do exist, highlighting the importance of identifying additional therapeutic vulnerabilities in ccRCC. We have recently performed some genome-wide screening and identified new signaling pathways regulated by VHL, including ZHX2 and SFMBT1 that play important roles in ccRCC. In addition, we also identified some synthetic lethality binding partners for VHL loss in kidney cancer, including TBK1. However, it is challenging to target TBK1 in clinical practice due to lack of selectivity for TBK1 inhibitors and its role involved in innate immune signaling. To overcome this difficulty, one approach would be to identify a critical upstream regulator of TBK1 that can be targeted therapeutically, especially in ccRCC displaying hyper-activated TBK1 activity due to VHL loss. We have performed a kinome-wide screening and identified Doublecortin like kinase 2 (DCLK2), an enigmatic kinase involved in neuronal survival and growth cone regeneration upon injury, as a novel TBK1 regulator in ccRCC. Our functional assays demonstrate that DCLK2 is necessary and sufficient to promote ccRCC tumorigenesis through activating TBK1. In addition, we also characterized a DCLK2 short isoform (DCLK2203) that play a predominant role in ccRCC tumorigenesis. Our work suggests that DCLK2 is a novel TBK1 activator and potential therapeutic target in ccRCC. Citation Format: Qing Zhang. Identification of potential new therapeutic targets in kidney cancer [abstract]. In: Proceedings of the AACR Special Conference: Advances in Kidney Cancer Research; 2023 Jun 24-27; Austin, Texas. Philadelphia (PA): AACR; Cancer Res 2023;83(16 Suppl):Abstract nr IA004.