Abstract 277: Cancer-associated fibroblasts, educated by tumor cells, differentially facilitate cancer cell invasion in cell-line based human gastric tumoroids

Abstract Purposes: Gastric cancer can be categorized into two subtypes: intestinal and diffuse. The latter is notorious for frequent peritoneal metastasis, resulting in a poorer prognosis. Cancer-associated fibroblasts (CAFs) in the tumor microenvironment play crucial roles in tumor invasion and metastasis. However, little is known about whether CAFs are associated with the differential progression between the two subtypes of gastric tumors. This study investigated whether differential cancer invasion may be attributed to tumor-specific CAF activation, using a cell-line-based human gastric tumoroid model. Methods: Heterotypic tumor spheroids (TS) were prepared with human gastric cancer lines of intestinal (MKN28, MKN74) and diffuse type (MKN45, KATO III) mixed with human gastric fibroblasts (HGFs) using a minipillar-array chip previously developed. Invasion phenotype and expression of epithelial-mesenchymal transition (EMT) -related proteins were evaluated in heterotypic TSs. mRNA expression in HGFs isolated from heterotypic TSs was analyzed and compared between the two subtypes. Results: While both heterotypic TSs displayed increased invasion by HGFs, the diffuse type TS showed a higher level of invasion with individual or amoeboid migration and loose binding of cancer cells with HGF. In contrast, the intestinal type TS showed collective migration and tight binding between cancer cells and HGFs. HGFs in each heterotypic TS exhibited differential morphology, matrix remodeling patterns, and gene expression in a tumor subtype-specific manner. Compared to normal HGFs, HGFs isolated from diffuse heterotypic TS showed enriched expression of cytoskeleton-associated genes and several integrins, whereas those of intestinal heterotypic TS exhibited increased expression levels of inflammatory cytokines. Conclusions: This study established tumoroid models for human gastric cancer subtypes, intestinal and diffuse, using heterotypic TS culture. Our results suggest that the subtype-specific invasion ability of tumor cells is driven by CAFs that are differentially educated by tumor cells in the tumor microenvironment. Our model not only advances our understanding of CAFs' role in tumor progression but also offers an in vitro model for assessing potential therapeutic targets and drug candidates for human gastric cancers. Citation Format: Hyun Ju Hwang, Saet-Byeol Lee, Hyo-Jeong Kuh. Cancer-associated fibroblasts, educated by tumor cells, differentially facilitate cancer cell invasion in cell-line based human gastric tumoroids 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 277.