摘要
AIM: To elucidate the molecular and cellular features responsible for the increase of regulatory T cells (Tregs) in gastric cancer. METHODS: The frequencies of CD4 + Foxp3 + Tregs and the level of transforming growth factor-β1 (TGF-β1) were analyzed from 56 patients with gastric cancer byflow cytometry and enzyme-linked immunosorbent assay respectively. Foxp3 gene expression was analyzed by real-time polymerase chain reaction. The gastric cancer microenvironment was modeled by establishing the coculture of gastric cancer cell line, MGC-803, with sorting CD4 + T cells. The normal gastric mucosa cell line, GES-1, was used as the control. The production of TGF-β1 was detected in supernatant of MGC and GES-1. The carboxyfluorescein diacetatesuccinimidyl ester (CFSE) dilution assay was performed to evaluate the proliferation characteristics of induced Tregs. Neutralizing anti-TGF-β1 antibody was added to the co-culture system for neutralization experiments. RESULTS: The level of serum TGF-β1 in gastric cancer patients (15.1 ± 5.5 ng/mL) was significantly higher than that of the genderand age-matched healthy controls (10.3 ± 3.4 ng/mL) (P < 0.05). Furthermore, the higher TGF-β1 level correlated with the increased population of CD4 + Foxp3 + Tregs in advanced gastric cancer (r = 0.576, P < 0.05). A significant higher frequency of CD4 + Foxp3 + Tregs was observed in PBMCs cultured with the supernatant of MGC than GES-1 (10.6% ± 0.6% vs 8.7% ± 0.7%, P < 0.05). Moreover, using the purified CD4 + CD25 T cells, we confirmed that the increased Tregs were mainly induced from the conversation of CD4 + CD25 naive T cells, and induced Tregs were functional and able to suppress the proliferation of effector T cells. Finally, we demonstrated that gastric cancer cells induced the increased CD4 + Foxp3 + Tregs via producing TGF-β1. Gastric cancer cells upregulated the production of TGF-β1 and blockade of TGF-β1 partly abrogated Tregs phenotype. CONCLUSION: Gastric cancer cell can induce Tregs development via producing TGF-β1, by which the existence of cross-talk between the tumor and immune cells might regulate anti-tumor immune responses.
AIM： To elucidate the molecular and cellular features responsible for the increase of regulatory T cells （Tregs） in gastric cancer. METHODS： The frequencies of CD4 ＋ Foxp3 ＋ Tregs and the level of transforming growth factor-β1 （TGF-β1） were analyzed from 56 patients with gastric cancer byflow cytometry and enzyme-linked immunosorbent assay respectively. Foxp3 gene expression was analyzed by real-time polymerase chain reaction. The gastric cancer microenvironment was modeled by establishing the coculture of gastric cancer cell line, MGC-803, with sorting CD4 ＋ T cells. The normal gastric mucosa cell line, GES-1, was used as the control. The production of TGF-β1 was detected in supernatant of MGC and GES-1. The carboxyfluorescein diacetatesuccinimidyl ester （CFSE） dilution assay was performed to evaluate the proliferation characteristics of induced Tregs. Neutralizing anti-TGF-β1 antibody was added to the co-culture system for neutralization experiments. RESULTS： The level of serum TGF-β1 in gastric cancer patients （15.1 ± 5.5 ng/mL） was significantly higher than that of the genderand age-matched healthy controls （10.3 ± 3.4 ng/mL） （P 0.05）. Furthermore, the higher TGF-β1 level correlated with the increased population of CD4 ＋ Foxp3 ＋ Tregs in advanced gastric cancer （r = 0.576, P 0.05）. A significant higher frequency of CD4 ＋ Foxp3 ＋ Tregs was observed in PBMCs cultured with the supernatant of MGC than GES-1 （10.6% ± 0.6% vs 8.7% ± 0.7%, P 0.05）. Moreover, using the purified CD4 ＋ CD25 T cells, we confirmed that the increased Tregs were mainly induced from the conversation of CD4 ＋ CD25 naive T cells, and induced Tregs were functional and able to suppress the proliferation of effector T cells. Finally, we demonstrated that gastric cancer cells induced the increased CD4 ＋ Foxp3 ＋ Tregs via producing TGF-β1. Gastric cancer cells upregulated the production of TGF-β1 and blockade of TGF-β1 partly abrogated Tregs phenotype. CONCLUSION： Gastric cancer cell can induce Tregs development via producing TGF-β1, by which the existence of cross-talk between the tumor and immune cells might regulate anti-tumor immune responses.
基金
Supported by Shanghai Municipal Natural Science Foundation, No. 10ZR1420000
National Natural Science Foundation of China, No. 81072009
