Alteration of Adaptive Immunity in a Colorectal Peritoneal Carcinomatosis Model

Colorectal cancer (CRC) usually gives rise to transcoelomic spread and ultimately causes peritoneal carcinomatosis (PC). However, mechanism studies, especially the immunological basis of colorectal PC, are rarely revealed due to lack of a suitable PC model. Here we selected a mouse colorectal cancer cell line MC-38 for intraperitoneal inoculation in the C57BL/6 mice to mimic the development of colorectal PC. We demonstrated that the injected CRC cells preferentially and rapidly migrated and colonized in the visceral fat tissues, but not in other visceral organs. With flow cytometric analysis, we found the proportions of spleen T cells and B cells were not affected by PC progression, while the ratios of blood CD4+ and CD8+ T cells were largely influenced. Especially, the quantity or activity of CD4+ and CD8+ T cells in visceral fats were intimately regulated by PC development. Taken together, we successfully constructed a colorectal PC model in immune-competent mice and revealed the alteration of adaptive immunity in PC development. Our study might potentiate the research and therapy strategies of colorectal PC.