LAUSR

Abnormal activating mutation of KRAS is frequently found in many human cancers, including pancreatic ductal adenocarcinoma (PDAC), colorectal cancer (CRC), and non-small cell lung cancer (NSCLC). KRAS activating mutations lead to hyperactivation of the MAPK/ERK signaling pathway, resulting in promotion of cell proliferation and growth. SOS1 is one of the major guanine nucleotide exchange factors (GEFs) that regulates RAS proteins including KRAS. Since SOS1 plays a critical role in converting the GDP-bound inactive KRAS “off” state to the GTP-bound active KRAS “on” state, disruption of SOS1 and KRAS protein-protein interaction would be effective to block KRAS-driven oncogenic signaling regardless of its mutation status. Importantly, SOS1 activity is crucial during the reactivation of the KRAS/MAPK signaling upon the treatment of RAS/MEK/ERK inhibitors, thus a SOS1 inhibitor would be an effective therapeutic option to treat KRAS-driven tumors in combination with RAS pathway inhibitors. We developed potent, selective, and orally available small molecules that effectively disrupt the interaction between SOS1 and KRAS. Current lead compounds originated from a virtual screening displayed excellent ADME and PK profiles. In cellular assays, a robust reduction of phospho-ERK level and cancer cell growth were shown. We also observed excellent in vivo antitumor activity in the mouse xenograft models. Moreover, combination with Sotorasib synergistically inhibited tumor cell growth both in vitro and in vivo. Overall, our SOS1 inhibitors demonstrate great therapeutic potential for cancer patients with KRAS mutations. Citation Format: Ha Na Yu, Dong Hyuk Ki, Joonwoo Nam, Eun-Jung Kim, Sungeun Kim, Hunmi Choi, Jieun Kim, Jihyun Yu, Donggeon Kim, Dohyun Park, Kyeong Jin Yoon, Seongin Jo, So-Hyeon Hwang, Sang Kyun Lim, Young Sook Shin, Wooseok Han. Discovery of potent and orally available small molecule inhibitors of the SOS1-KRAS interaction [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 515.