Abstract 47: Cancer-associated fibroblasts mediate extracellular matrix remodeling and three-dimensional invasion of scirrhous gastric carcinoma cells

Abstract

Abstract Scirrhous gastric carcinoma (SGC; also called diffusely infiltrative carcinoma, Borrmann's type-IV carcinoma, or the linitis plastica-type carcinoma) have the worst prognosis among various types of gastric cancer, owing to highly progressive invasion, frequent metastasis to lymph nodes, and high incidence of peritoneal dissemination. SGC cells rapidly and diffusively infiltrate through the submucosa without forming obvious tumor mass and induce extensive stromal fibrosis, resulting in thickening and stiffening of the gastric wall. Because histophathological analyses have shown that massive proliferation of stromal fibroblasts occur within lesions of SGC, cancer-associated fibroblasts (CAFs) have been proposed to support the progression of SGC. However, biological and molecular basis of the interaction between SGC cells and CAFs remains largely unknown. In this study, we investigated the roles of CAFs in invasion and extracellular matrix (ECM) remodeling by SGC cells. When 44As3 SGC cells were co-cultured with CaF37 SGC-derived fibroblasts on 3D Matrigel, they formed large cell aggregates that invade into the Matrigel. Other SGC cell lines, HSC59 and HSC44PE, but not differentiated non-SGC gastric caner cell lines, MKN7, MKN1, and MKN74, formed invasive cell aggregate with CaF37 cells. Time-lapse imaging of SGC and CaF37 cells, and of fluorescent microsphere embedded in the Matrigel revealed that this process is associated with extensive contraction and remodeling of ECM. In order to further characterize the ECM remodeling activity of CAFs, we cultured 44As3 and CaF37 cells on fluorescent gelatin-coated coverslips. CaF37 cells caused disruption of the gelatin matrix and this activity was further promoted by co-culturing them with 44As3 cells. Immunoblotting and immnofluorescence analyses revealed that phosphorylation of myosin light chain was significantly increased in CaF37 cells co-cultured with 44As3 cells. Finally, a myosin II inhibitor blebbistatin blocked the three-dimensional invasion and ECM remodeling by 44As3 and CaF37 cells. These results indicate that SGC cells promote actomyosin-mediated contractility of stromal fibroblasts to remodel ECM during invasion. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 47. doi:1538-7445.AM2012-47