Abstract 1271: PMEPA1 acts as a switch to modulate cooperative cellular invasion and drive NSCLC tumor progression

Abstract Metastatic disease drives cancer patient mortality. One primary mode of metastasis is collective invasion, whereby cohesive groups of cells invade into the adjacent stroma while maintaining cell-cell contacts. Importantly, these cellular packs harbor genetically and phenotypically heterogeneous subpopulations that cooperate to drive invasion. To deconstruct how phenotypic cellular heterogeneity facilitates distinct molecular profiles within a single tumor, we established the technique Spatiotemporal Cellular and Genomic Analysis (SaGA). SaGA is an image-guided approach that optically highlights phenotypically defined cell (s) for live fluorescence-activated cell sorting and analysis. To elucidate the transcriptional heterogeneity across invasive packs within a 3D physiologically-relevant microenvironment, we combined SaGA with single cell RNA sequencing for isolation and analysis of actively invading cells. This novel single cell transcriptomics approach reveals that - during cellular invasion into the microenvironment - the follower subpopulation supplies TGFβ to heterogeneously stimulate both autocrine canonical and paracrine noncanonical signaling pathways. This cooperative exchange facilitates a symbiotic relationship between tumor subpopulations in non-small cell lung carcinoma both in vitro and in vivo. In vitro, we determine that PMEPA1 protein levels mitigate TGFβ downstream effector signaling within heterogeneous tumor cells to modulate JAG1 expression and activity. In vivo, we show that a reduction in JAG1 levels decreases primary tumor cell invasion and progression. We mechanistically define a TGFβ-PMEPA1-JAG1 signaling axis across leader and follower subpopulations critical for tumor cell invasion and cancer progression. Together, these data highlight the importance of cellular heterogeneity and subpopulation communication required for tumor progression. Citation Format: Tala O. Khatib, Brian A. Pedro, Christina M. Knippler, Veronika Y. Matsuk, Sarah F. Webster, Sergei Bombin, Bhakti Dwivedi, Jeanne Kowalski, Henry R. Johnston, Janna K. Mouw, Adam I. Marcus. PMEPA1 acts as a switch to modulate cooperative cellular invasion and drive NSCLC tumor progression 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 1271.