The Expression Of B7-H4 In Human Colon Carcinoma And Its Clinical Significance

Objective: To explore the expression of B7-H4 in human colon cancer,and initially investigate the relationship among B7-H4 expression, CD4~+CD25~+ regulatory T cells and Interleukin-10.Methods: To collect 60 specimens of human colon cancer via operation in the department of Gastric and Intestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, all had been confirmed by the department of pathology. For the colon cancer tissues and normal colon tissues, immunohistochemistry (IHC)was used to examine the B7-H4 expression; fluorescence activated cell sorting (FACS)was used to examine the B7-H4 expression, the content of regulatory T cell; for CD4~+ CD25~+ regulatory T cells from tissues and CD4~+ CD25- conventional T cells from healthy human peripheral blood, which were isolated by inmunomagnetic beads, while western blotting and fluorescence activated cell sorting were used to examine the expression of interleukin-10 in these cells; similarly, CD4~+ CD25~+ regulatory T cells from cancer tissues and peripheral blood mononuclear cells from healthy human were culthered togehter 48h for exploring the B7-H4 expression on mononuclear cells.Results: 1. IHC showed that colon cancer tissues had a high level expression of B7-H4, while nearly no expression in the normal colon tissues; FACS showed the B7-H4 expression ratio and corresponding MFI were 62±8% and 2480±320 in cancer, while the date were 10±2% and 400±80 in the normal tissues (P<0.05). Moreover, B7-H4 truely expressed on the surface of tumor associated macrophages.2. FACS showed the Foxp3~+ expression ratio were 22±5% and 5±3% in CD3~+ CD4~+ T cells in the cancer tissues and normal tissues respectively(P<0.05). 3. Western blotting displayed that the content of IL-10 in CD4~+ CD25~+ regulatory T cells is significant higher than in CD4~+ CD25- conventional T cells; at the same time, ELISA showed in the supernatant fluid via col-culther, the IL-10 concentration were 200±25pg/ml and 50±8pg/ml respectively (P<0.05).4. B7-H4 expressing induction in vitro showed that after a 48h col-culture, the B7-H4 expression ratio and corresponding MFI were 40±5% and 2000±100 in the group of monocytes and CD4~+ CD25~+ regulatory T cells ; while the group added anti-hIL-10 only were 7±3% and 400±80; the lowest group was monocytes cultured alone, 5±2% and 300±50 (P<0.05).Conclusion: B7-H4 expresses in human colon cancer with a high level, and the expression is localized on the cell membrane of tumor associated macrophages; CD4~+CD25~+ regulatory T cells may be a imporment source of IL-10 in the tumor microenvironment and can induce B7-H4 expression on monocytes, moreover, IL-10 may play an essencial role in the induction of B7-H4.