Abstract 218: Deciphering tumoroid-CAF interactions through a spatially segregated coculture model

Abstract In the context of lung cancers, cancer-associated fibroblast (CAF) plays a pivotal role as a key component of the tumor microenvironment (TME), affecting tumor growth, invasion, metastasis, immune modulation, and drug resistance. Despite the recognized impact of CAFs, the precise interaction between the CAF and tumor cell remains elusive. Previous studies have reported that CAFs stimulate tumor cell growth both in vitro and in vivo. However, our tumoroid models reveal an intriguing phenomenon where CAFs inhibit tumoroids growth within Matrigel. This led us to hypothesize that paracrine signaling might be the primary mode of interaction between CAFs and tumor cells. To unravel the intricacies of this interaction, we developed an innovative coculture method. Using hydrophobic barrier, we segregated the coculture of nine sets of CAFs and tumoroids within a single well, preventing CAFs from infiltrating the tumoroid culture area. This setup enabled interaction solely through paracrine signaling. Surprisingly, cocultured tumoroids exhibited no significant differences compared to individually cultured tumoroids. Conversely, cocultured CAFs displayed a remarkable increase in growth compared to their individually cultured counterparts. This suggests that tumoroids influence CAF growth, while CAFs do not significantly impact tumoroid growth. Furthermore, in three coculture sets, tumor cells within the Matrigel migrated towards the CAF culture area, indicating that CAFs induce tumor cell metastasis. Immunofluorescence staining confirmed this metastatic phenomenon. To identify the paracrine factors influencing CAFs and tumoroids, we employed RNA-sequencing, single-cell RNA-sequencing, and proteomic analysis of culture soup. Proteomic analysis revealed a substantial increase in proteins and signaling pathways related to the extracellular matrix in cocultures compared to single cultures. Our findings suggest that tumor cells recruit CAFs, promoting CAF growth to establish and fortify their TME, ultimately leading to drug resistance, metastasis, and immune modulation Citation Format: Sung Min Kim, Yoo Ri Ko, Hye Seon Park, Se Jin Jang. Deciphering tumoroid-CAF interactions through a spatially segregated coculture model 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 218.