Department of Laboratory Medicine, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China.
World J Gastroenterol. 2011 Apr 21;17(15):2019-27. doi: 10.3748/wjg.v17.i15.2019.
To elucidate the molecular and cellular features responsible for the increase of regulatory T cells (Tregs) in gastric cancer.
The frequencies of CD4(+)Foxp3(+) Tregs and the level of transforming growth factor-β1 (TGF-β1) were analyzed from 56 patients with gastric cancer by flow 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 co-culture 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.
The level of serum TGF-β1 in gastric cancer patients (15.1 ± 5.5 ng/mL) was significantly higher than that of the gender- and 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.
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.
阐明导致胃癌中调节性 T 细胞（Tregs）增加的分子和细胞特征。
通过流式细胞术和酶联免疫吸附试验分别分析了 56 例胃癌患者的 CD4(+)Foxp3(+)Tregs 频率和转化生长因子-β1（TGF-β1）水平。通过实时聚合酶链反应分析 Foxp3 基因表达。通过建立胃癌细胞系 MGC-803 与分选 CD4(+)T 细胞的共培养来模拟胃癌微环境。正常胃黏膜细胞系 GES-1 用作对照。检测 MGC 和 GES-1 上清液中 TGF-β1 的产生。用羧基荧光素二乙酸琥珀酰亚胺酯（CFSE）稀释试验评估诱导的 Tregs 的增殖特征。向共培养系统中加入中和抗 TGF-β1 抗体进行中和实验。
胃癌患者（15.1 ± 5.5 ng/mL）血清 TGF-β1 水平明显高于性别和年龄匹配的健康对照者（10.3 ± 3.4 ng/mL）（P < 0.05）。此外，较高的 TGF-β1 水平与晚期胃癌中 CD4(+)Foxp3(+)Tregs 数量的增加相关（r = 0.576，P < 0.05）。与 GES-1 相比，用 MGC 上清液培养的 PBMC 中观察到 CD4(+)Foxp3(+)Tregs 的频率明显更高（10.6%±0.6% vs 8.7%±0.7%，P < 0.05）。此外，使用纯化的 CD4(+)CD25(-)T 细胞，我们证实增加的 Tregs 主要是由 CD4(+)CD25(-)幼稚 T 细胞的转化诱导的，诱导的 Tregs 是有功能的，能够抑制效应 T 细胞的增殖。最后，我们证明了胃癌细胞通过产生 TGF-β1 诱导 CD4(+)Foxp3(+)Tregs 的增加。胃癌细胞上调 TGF-β1 的产生，阻断 TGF-β1 部分消除了 Tregs 表型。
胃癌细胞可以通过产生 TGF-β1 诱导 Tregs 的发育，通过这种方式，肿瘤和免疫细胞之间的相互作用可能调节抗肿瘤免疫反应。
