Abstract LB-486: Overexpression of a mutated, constitutively active HIF2α promotes the carcinogenesis of TRACK mouse

Abstract

Abstract Background: VHL disease patients have an increased risk of developing clear cell renal cell carcinomas (ccRCC). Increased expression of HIF1α and/or HIF2α has been proposed as a key step in ccRCC carcinogenesis. We recently reported a mouse model of VHL renal cancer, the TRACK model (Fu et al, Cancer research. 2011;71(21):6848-56.). In the TRACK model, proximal tubule (PT) cell overexpression of a triple mutant (P402A, P564A and N803A) HIF1α in the mouse mimics human VHL kidney disease. Methods: Here we report a mouse model expressing a triple mutant (P405A, P531A and N847A) HIF2α in PT cells. Mutant HIF2α was expressed in both WT and HIF1α-expressing C57BL/6 mice. Results: Transgenic (TG) mice expressing this HIF2α construct specifically in PT cells exhibit vacuolization consistent with glycogen accumulation and hydropic degeneration. The activation of HIF2α was confirmed by increased expression of HIF2α target genes, e.g. CA9. Neoplastic transformation was not observed in the kidneys of HIF2α TG+ mice. In HIF1α/HIF2α-expressing mice, disorganized PT cells mimicking in situ carcinoma was observed in 5 mo old mouse kidneys, which was seen only at 14 mo in mice expressing only mutant HIF1α. Conclusions: These data suggest HIF2α accelerates carcinogenesis in the mutant HIF1α TRACK model. These mouse models provide excellent models to study VHL renal disease and carcinogenesis, and provide an opportunity for chemoprevention studies. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-486. doi:1538-7445.AM2012-LB-486