LAUSR

KRAS is the most frequently mutated oncogene in human cancers and had long been considered an undruggable target for cancer therapy, until the FDA approval of Sotorasib (AMG 510) for the treatment of patients with non-small cell lung cancer (NSCLC) harboring the KRAS (G12C) mutation. To gain more insights into AMG 510 therapeutic mechanisms, herein we carried out a genome-scale CRISPR Cas9 knock-out screen in a KRAS G12C-harboring NCI-H2122 xenograft model. We first generated a stable NCI-H2122 cell line overexpressing Cas9 and confirmed its Cas9 editing efficiency by a BFP-GFP dual reporter system. Referring to our previous study for in vivo subcutaneous xenograft growth and response to AMG 510 treatment of NCI-H2122 cell line in immunodeficient mice, we decided to conduct the in vivo screens using 10M cell inoculation each mouse. We infected NCI-H2122 Cas9 cells with the genome-wide Brunello guide RNA library. After puromycin selection and two passages of cell recovery, the resultant cells were inoculated into Nu/nu mice subcutaneously, with part of cells collected as baseline. Mice bearing tumors were grouped into three groups at average tumor size of around 200 mm3 for vehicle, 10 or 30 mpk AMG510 treatment. Tumors were collected while the average tumor size of vehicle treatment group reached around 800 mm3. Genomic DNA was extracted from both baseline cell samples and tumor samples followed by Next-generation sequencing. We have performed QC analysis for all the samples and will discuss the hits from the screen and their implication in AMG 510-induced cancer sensitivity and resistance. Citation Format: Haixin Zhao, Fangzheng Zhai, Bin Li, Qiangqiang Fan, Zhengang Peng. CDX model based genome-scale CRISPR KO screens for modulators of KRAS (G12C) inhibitor sensitivity [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 257.