ATDC binds to KEAP1 to drive NRF2-mediated tumorigenesis and chemoresistance in pancreatic cancer

Pancreatic ductal adenocarcinoma is a lethal disease characterized by late diagnosis, propensity for early metastasis and resistance to chemotherapy. Little is known about the mechanisms that drive innate therapeutic resistance in pancreatic cancer. The ataxia-telangiectasia group D-associated gene (ATDC) is overexpressed in pancreatic cancer and promotes tumor growth and metastasis. Our study reveals that increased ATDC levels protect cancer cells from reactive oxygen species (ROS) via stabilization of nuclear factor erythroid 2-related factor 2 (NRF2). Mechanistically, ATDC binds to Kelch-like ECH-associated protein 1 (KEAP1), the principal regulator of NRF2 degradation, and thereby prevents degradation of NRF2 resulting in activation of a NRF2-dependent transcriptional program, reduced intracellular ROS and enhanced chemoresistance. Our findings define a novel role of ATDC in regulating redox balance and chemotherapeutic resistance by modulating NRF2 activity.

Abstract A21: TRIM29 promotes invasion and migration of bladder cancer cells by regulating myosin-intermediate filament network and focal adhesion

Development of invasive progression in human bladder cancer is a key determinant of patient outcomes. Therefore, understanding the drivers of bladder cancer invasive progression is critical to improving patient care. We have previously shown that TRIM29 (also known as ataxia-telangiectasia group D complementing gene, ATDC) is highly expressed in muscle-invasive bladder cancer and plays an important role in driving tumor formation and invasion in vitro and in vivo. TRIM29 is upregulated by TP63 in basal subtype tumors, but the mechanism by which TRIM29 promotes tumor invasion was unknown. To elucidate the mechanism by which TRIM29 drives bladder cancer invasion, we developed a 3-D bladder cancer spheroid invasion assay that allows observation of the invasive process of cancer spheroids in a real-time fashion and observation of protein expression using confocal microscopy. Using this system, we confirmed that TRIM29 is required for bladder cancer stromal invasion. To determine if TRIM29 is specifically required for cell migration, which is an important ability contributing to invasive behavior, scratch assays were performed and we found TRIM29 is required for migration. Cancer cell migration requires modulation of cell adhesion and actin/myosin activation. To examine the role of TRIM29 in cell adhesion and motility, gene knockout or knockdowns of TRIM29 were generated in human bladder cancer cell lines (UM-UC5, UC9, UC13, UC14). Interestingly, TRIM29 KO/KD downregulates the expression of keratin 14 (KRT14), a member of type I keratin family that constitutes intermediate filament (IF) network, as well as myosin IIA (MYH9), a non-muscle motor protein that is essential for cell adhesion and migration. Using immunofluorescent confocal microscopy, we found that TRIM29 also modulates formation of focal adhesion plaques in bladder cancer during cell migration. Taken together, these findings suggest a novel mechanism by which TRIM29 regulates bladder cancer cell motility and invasion.

Citation Format: Yin Wang, Erica R. Gumkowski, Phillip L. Palmbos. TRIM29 promotes invasion and migration of bladder cancer cells by regulating myosin-intermediate filament network and focal adhesion [abstract]. In: Proceedings of the AACR Special Conference on Bladder Cancer: Transforming the Field; 2019 May 18-21; Denver, CO. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(15_Suppl):Abstract nr A21.