Abstract LB043: Identification and characterization of cancer-associated fibroblast subpopulations in lung adenocarcinoma

Background: Cancer-associated fibroblasts (CAFs) reside within the tumor microenvironment, facilitating cancer progression and metastasis via direct and indirect interactions with cancer cells as well as other stromal cell types. CAFs are comprised of heterogeneous subpopulations of activated fibroblasts, including myofibroblastic, inflammatory, or immunosuppressive CAFs. In this study, we sought to identify subpopulations of CAFs isolated from human lung adenocarcinomas and describe their transcriptomic as well as functional characteristics through single-cell RNA sequencing (scRNA-seq) and subsequent bioinformatics analyses. Methods: We isolated and cultured two types of CAFs. Total CAFs were isolated after negative selection using cell-type-specific antibodies against lymphocytes (CD45), macrophages (CD68), endothelial cells (CD31), and epithelial cells (Ep-CAM). THY1+ CAFs were isolated after additional selection based on CAF-specific marker THY1. Total CAFs (n=5,139 cells) and THY1+ CAFs (n=4,038 cells) were subjected to 10X Genomics scRNA-seq. scRNA-seq data were then integrated and analyzed using the Seurat method. Results: Cell trajectory analysis of combined total and THY1+ CAFs revealed two branching points with five distinct branches. Based on Gene Ontology analysis, we denoted Branch 1 as “immunosuppressive”, Branch 2 as “neoantigen-presenting”, Branch 4 as “myofibroblastic”, and Branch 5 as “proliferative” CAFs. We selected representative branch-specific markers and measured their expression levels in total and THY1+ CAFs. We also investigated the effects of these markers on CAF activity under co-culture with lung cancer cells. Conclusions: This study describes novel subpopulations of CAFs in lung adenocarcinoma, highlighting their potential value as therapeutic targets. Citation Format: Daeseung Kim, Jeong Seon Kim, Seoree Kim, Sang Hoon Chun, Jae Jun Kim, Inyoung Cheon, Sieun Lee, Jung Sook Yoon, Soon Auck Hong, Hye Sung Won, Keunsoo Kang, Young-Ho Ahn, Yoon Ho Ko. Identification and characterization of cancer-associated fibroblast subpopulations in lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB043.