Abstract 579: Assessing the longitudinal efficacy of anti-PD-1 therapy in a murine non-small cell lung cancer model using single-cell and spatial transcriptomics

Abstract Lung cancer has a high incidence rate and is the main cause of cancer-related deaths with 127, 070 fatalities expected in the U. S. this year. Non-small cell lung cancer (NSCLC) accounts for an estimated 85% of all lung cancer cases and is typically diagnosed at an advanced disease stage, where outcomes are often poor and treatment options are limited. Targeted therapies are only available to a minority of NSCLC patients with identifiable tumor-driving mutations. Anti-programmed cell death protein 1 (anti-PD-1) immunotherapy has become a first-line treatment strategy for patients without tumor-driving gene mutations. However, only 15-20% of NSCLC patients exhibit a positive response to anti-PD-1 therapy. Moreover, patients who initially respond to anti-PD-1 therapy still face the risk of primary or acquired resistance, potentially leading to cancer progression. This study leverages a murine lung cancer cell line representative of NSCLC isolated from a genetically engineered mouse model expressing KrasG12D and P53−/flox oncogenic mutations in club cells, employing a cell type-specific promoter (Scgb1a1). After successfully establishing the oncogenic cell line, the cells were subcutaneously injected into immunocompetent C57BL/6 mice and subjected to anti-PD-1 therapy for 3 weeks post-injection. Tumor growth curves revealed a significant size reduction in anti-PD-1-treated tumors when compared to the IgG isotype control group, as confirmed by a paired t-test analysis (p 0. 045). To evaluate the longitudinal dynamics of the tumor microenvironment, single-cell sequencing, and spatial transcriptomics were performed throughout effective anti-PD-1 treatment and following tumor relapse. Samples were collected at 2 time points during anti-PD-1 treatment, specifically at 1 and 3 weeks, as well as 3 weeks after the completion of the anti-PD-1 treatment. Subsequently, these samples underwent single-cell RNA sequencing and spatial transcriptomics using the 10x Genomics platform. Single-cell sequencing revealed modulations in immune recruitment throughout the treatment while relapsed tumors display elevated levels of myeloid gene expression and a shift to a highly fibrotic tumor phenotype post-anti-PD-1 therapy. These findings suggest that the established oncogenic cell line exhibits initial responsiveness to anti-PD-1 therapy in vivo before undergoing major changes within the tumor microenvironment. This study highlights the relevance and translational potential of our oncogenic cell line in advancing our understanding of NSCLC and its response to anti-PD-1 therapy. *This work was performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-857319. Citation Format: Nicole F. Leon, Oscar A. Davalos, David Baliu-Rodriguez, Deepa K. Murugesh, Aimy Sebastian, Nicholas R. Hum. Assessing the longitudinal efficacy of anti-PD-1 therapy in a murine non-small cell lung cancer model using single-cell and spatial transcriptomics 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 (6Suppl): Abstract nr 579.