Abstract B068: A novel murine model for interrogating immune response to tumor heterogeneity in non-small cell lung cancer

Abstract Resistance to immune checkpoint inhibitors (ICIs) represents a major barrier to effectively treating patients with NSCLC. Increased tumor heterogeneity has been linked with diminished response to ICIs, but the mechanisms underlying such an effect remain underexplored, in part due to the lack of models for studying the impact of heterogeneity. To address this issue, we have developed a novel murine model of NSCLC that utilizes clonal cell lines to modulate tumor heterogeneity. Specifically, we isolated single cells from a murine NSCLC cell line harboring 3 common driver mutations (Kras G12D Tp53 +/- Lkb1 -/- , or “KPL”). We mutagenized KPL cells with N-methyl-N-nitrosourea in order to increase the tumor mutational burden, and then isolated single cells to derive clonal cell lines. Whole exome sequencing and subsequent phylogenetic analysis of tumor mutations yielded categorization of these clones into 5 clusters. Clones within the same cluster demonstrated comparable in vivo growth kinetics and similar response to anti-PD-1 immunotherapy. These clones exhibited unique tumor immune microenvironments that did not fully correlate with genomic factors such as tumor mutation burden. Notably, heterogeneous polyclonal tumors grew more aggressively than monoclonal tumors, and they exhibited response to anti-PD-1 therapy that differed from the response seen in the component single clones. Tracking of individual clones with fluorescent proteins and mutation tracing illustrated clonal shifts induced by ICI treatment. Our results validate this system as a model of NSCLC that can modify tumor heterogeneity and provide insights into the effects of heterogeneity on ICIs and other immunotherapies. Citation Format: Michael Oh, Jensen W Abascal, Linh M Tran, Ramin Salehi-Rad, Raymond J Lim, Camelia Dumitras, Cara Yean, Sunny Xiao, Bitta P Kahangi, William P Crosson, Edgar Perez Reyes, Nalani Coleman, Austin K Rennels, Kostyantyn Krysan, Bin Liu, Steven M Dubinett. A novel murine model for interrogating immune response to tumor heterogeneity in non-small cell lung cancer [abstract]. In: Proceedings of the AACR IO Conference: Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2025 Feb 23-26; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2025;13(2 Suppl):Abstract nr B068.