Targeted Degradation of SOS1 Exhibits Potent Anticancer Activity and Overcomes Resistance in KRAS-Mutant Tumors and BCR–ABL–Positive Leukemia

作者：Ziwei Luo, Chencen Lin, Chuwei Yu, Changxian Yuan, Wenyong Wu, Xiaowei Xu, Renhong Sun, Yan Jia, Yafang Wang, Jie Shen, Dingyan Wang, Sinan Wang, Hualiang Jiang, Biao Jiang, Xiaobao Yang, Chengying Xie · 发表于：Cancer Research · 年份：2024 · DOI：10.1158/0008-5472.can-24-1093 · 被引用次数：16 · 研究领域：Protein Degradation and Inhibitors、Multiple Myeloma Research and Treatments、Peptidase Inhibition and Analysis

Son of sevenless homolog 1 (SOS1) is an essential guanine nucleotide exchange factor for RAS that also plays a critical role in the activation of the small GTPase RAC mediated by BCR-ABL in leukemogenesis. Despite this, small-molecule inhibitors targeting SOS1 have shown limited efficacy in clinical trials for KRAS-mutant cancers, and their potential as a therapeutic approach for chronic myeloid leukemia (CML) remains largely unexplored. In this study, we developed a potent SOS1 proteolysis targeting chimera (PROTAC) SIAIS562055, which was designed by connecting a CRBN ligand to an analog of the SOS1 inhibitor BI-3406. SIAIS562055 exhibited sustained degradation of SOS1 and inhibition of downstream ERK pathways, resulting in superior antiproliferative activity compared with small-molecule inhibitors. SIAIS562055 also potentiated the activity of both KRAS inhibitors in KRAS-mutant cancers and ABL inhibitors in BCR-ABL-positive CML. In KRAS-mutant xenografts, SIAIS562055 displayed promising antitumor potency as a monotherapy and enhanced ERK inhibition and tumor regression when combined with KRAS inhibitors, overcoming acquired resistance. In CML cells, SIAIS562055 promoted the active uptake of BCR-ABL inhibitors by upregulating the carnitine/organic cation transporter SLC22A4. SIAIS562055 and BCR-ABL inhibitors synergistically enhanced inhibition of ABL phosphorylation and downstream signaling, demonstrating robust antitumor activities in both mouse xenografts and primary samp...