Abstract: Objective To investigate the effects of mitogen-activated protein kinase (MAPK) signaling pathway on the differentiation of CD8+ regulatory T cells induced by ovarian cancer cell line SKOV3. Methods Coculture systerm of CD8+ T cells and SKOV3 were conducted in vitro, CD8+ T cells cultured alone group acted as control group. At day 5, CD8+ T cells were collected, mRNA and protein expression levels of CD28, CD25, Foxp3 in CD8+ T cells were detected by real-time PCR and flow cytometry, respectively. Western blot was used to detect the expression of p-ERK, ERK, p-JNK,JNK,p-p38MAPK and p38 MAPK. Proliferation assay was applied to analyze the effect of CD8+ T cells on na?ve CD4+ T cells. The phenotypic changes of CD8+T cells were determined after 4 hours pre-incubation with the specific inhibitors of p38 MAPK (SB203580). Results In co-cultured group the mRNA and protein expression levels of CD25 and Foxp3 were higher than those in the control group(P<0.05); and the expression level of CD28 was significantly lower than that in the control group(P<0.05); Result showed that the expression of p-p38 MAPK in the co-cultured group was significant higher than that in the control group (P<0.05); After pre-incubated with SB203580 for 4 hours, the phenotypic of CD8+Tregs was significantly decreased. Conclusions P38 MAP Kinase signaling is required for the generation of CD8+ Tregs induced by ovarian cancer cell, which might be benefit for tumor progression.

Key words: human ovarian cancer cell line, CD8+T cell, co-culture, MAPK patway