Abstract 4322: Inhibition of ULK and KRASG12C control tumor growth in preclinical models of lung cancer

Abstract

Abstract Approximately 30% of lung cancers are driven by mutationally activated KRAS. The recent FDA approval of sotorasib, a direct pharmacological inhibitor of KRASG12C, marks a critical milestone in the treatment of this important subset of lung cancer. However, a major obstacle in treating lung cancer is resistance to current therapeutic treatments. In response to cellular stresses such as RAS pathway-targeted therapeutics, RAS-mutated cancer cells have been demonstrated to increase autophagy, an intracellular recycling pathway. However, the mechanism(s) underlying treatment-induced autophagy is not well understood. Here, we demonstrate that KRASG12C-driven lung cancer cells increase autophagy in response to treatment with sotorasib. Currently, the only therapeutics in clinical use to inhibit autophagy are lysosomal inhibitors (hydroxy)chloroquine. High concentrations of these compounds are needed to achieve modest inhibition of autophagy, suggesting that the potency of these compounds may limit clinical responses. ULK kinases are serine/threonine kinases that are necessary for the initiation of autophagy. DCC-3116 is a potent inhibitor of the ULK1/2 protein kinases, master regulators of autophagy. Treatment with sotorasib and DCC-3116 led to superior anti-tumor effects in preclinical models of lung cancer. Additionally, about 30% of lung cancer patients with KRAS mutations also have deletions or inactivating mutations in LKB1, a protein involved in the regulation of nutrient sensing and autophagy. In other KRAS-driven cancers, the LKB1-AMPK-ULK1 signaling axis is a proposed mechanism as to how autophagic flux increases following KRAS pathway inhibition. However, our preliminary data demonstrates that LKB1 is dispensable for sotorasib-induced autophagy, suggesting the mechanism(s) of autophagy induction in KRASG12C-driven lung cancer may be different from those detected in other KRAS mutated cancers. Consequently, we have generated genetically engineered mouse models (GEMMs) of KRASG12C-driven lung cancer in which LKB1 is silenced to further investigate the role of LKB1 in the autophagy response of KRASG12C-driven lung cancers to pathway-targeted blockade of oncogenic KRAS signaling. We have treated KRASG12C-driven GEMMs with sotorasib and/or DCC-3116 to test the sensitivity of lung tumors to these treatment options. Citation Format: Phaedra Ghazi, Kayla O'Toole, Sanjana Boggaram, Michael Scherzer, Madhumita Bogdan, Bryan Smith, Dan Flynn, Conan Kinsey, Martin McMahon. Inhibition of ULK and KRASG12C control tumor growth in preclinical models of lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4322.