Abstract A38: MTH1 Inhibition as an effective tumor-suppressive strategy in RAS-driven cancer

Abstract

Abstract Oncogenic RAS mutations confer multiple malignant traits to cancer cells, many of which are mediated by oncogene-induced reactive oxygen species (ROS). However, oncogenic ROS also create vulnerabilities in the cancer cells, sensitizing them to oxidative DNA damage and strand breaks which can trigger cellular senescence or cell death. Thus RAS-driven tumor cells require adaptive redox protective mechanisms to inhibit ROS-associated tumor suppression. We previously reported that MutT Homolog 1 (MTH1), the mammalian 8-oxodGTPase, comprises one such critical adaptation. We have shown MTH1 is important for facilitating the full gamut of RAS-driven malignancy by promoting evasion of the first barrier to transformation, viz. oncogene-induced senescence (OIS), enhancing RAS-mediated transformation and related pro-malignant traits, and maintaining proliferation and tumorigenicity in established RAS-driven tumor cells. Recently chemical inhibitors against MTH1 have been developed, although there is some controversy surrounding their efficacy and mode of action. Our work here discusses RAS regulation of MTH1 expression, and the molecular contexts under which MTH1 inhibition can synergize with oncogenic oxidative stress in RAS-driven tumor cells for optimal tumor suppressive response. Citation Format: Govindi Jayanika Samaranayake, Clara Issabella Troccoli, Tyler Andrew Cunningham, Priyamvada Rai. MTH1 Inhibition as an effective tumor-suppressive strategy in RAS-driven cancer. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Targeting the Vulnerabilities of Cancer; May 16-19, 2016; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(1_Suppl):Abstract nr A38.