Inhibition of Discoidin Domain Receptor 1 Prevents Stroma-Induced Peritoneal Metastasis in Gastric Carcinoma

다국어 초록 (Multilingual Abstract)

<P>Discoidin domain receptor 1 (DDR1) is activated by fibrillar (triple-helical) collagens and collagen IV, which are major components of tumor stroma; thus, DDR1 might be a critical mediator of communication between cancer cells and stroma. The aim of this study was to investigate the effect of DDR1 inhibition on stroma-induced peritoneal metastasis in gastric carcinoma. We analyzed by immunohistochemistry the correlation between DDR1 expression and the pattern of recurrence in gastric carcinoma tissues from a previously characterized and established gastric carcinoma patient cohort. We also cocultured human gastric carcinoma cell lines with gastric cancer–associated fibroblasts (CAF) and investigated DDR1 expression and activation. We evaluated CAF-induced tumorigenic properties of gastric carcinoma cell lines and the effect of a DDR1-specific inhibitor in organotypic cultures and in a peritoneal seeding xenograft animal model. The expression of DDR1 in gastric cancer tissues was positively associated with early recurrence (<I>P</I> = 0.043) and a high incidence of peritoneal recurrence (<I>P</I> = 0.036). We confirmed that coculturing with CAFs elevated DDR1 protein expression in gastric carcinoma cell lines and enhanced gastric carcinoma cell line spheroid formation in organotypic cultures in a tumor cell DDR1-dependent manner. Coimplantation of CAFs with gastric carcinoma cells enhanced peritoneal tumor formation <I>in vivo</I>, an effect that was sensitive to pharmacologic inhibition of DDR1.</P><P><B>Implications:</B> This study highlights that CAF-induced elevation of DDR1 expression in gastric carcinoma cells enhances peritoneal tumorigenesis, and that inhibition of DDR1 is an attractive strategy for the treatment of gastric carcinoma peritoneal metastasis. <I>Mol Cancer Res; 16(10); 1590–600. ©2018 AACR</I>.</P>