调节性B细胞调控舌鳞癌间质纤维化的作用机制

Interstitial fibrosis contributes to tumor progression by its dynamic regulation with chronic inflammation in tumor microenvironment. Regulatory B cells (Bregs), characterized by IL-10 secretion, is a special subpopulation of B cells, and they are reported to function in T cells proliferation and differentiation. Our previous study revealed that tongue squamous cell carcinoma (TSCC) cells expressed tumor-originated Foxp3, and that tumor-originated Foxp3 cross-talked with Foxp3+ Tregs via TGF-β to induce immunosuppression in vitro, which, however, contradicted to "Tregs-Th17" microenvironment in vivo. Then our study showed IL-10 expression was up-regulated and CD19+ lymphocytes existed in TSCC tissues, which indicated that Bregs may function in TSCC inflammatory microenvironment. Based on studies above, we propose that Bregs regulate interstitial fibrosis by regulating Th17-Tregs inflammatory microenvironment in TSCC. We will at first analyze the association between interstitial fibrosis and TSCC clinipathologic features, and then investigate regulation mechanisms between Bregs, Tregs, Th17 and interstitial fibrosis in vitro and in vivo. We hope this study will illustrate a new theory in inflammatory microenvironment and interstitial fibrosis regulation.

间质纤维化是机体通过调节肿瘤微环境从而影响其发生发展的重要途径，肿瘤局部慢性炎症与间质纤维化同时存在、相互促进，但机制未明。调节性B细胞Bregs是B细胞的特殊亚群，以分泌IL-10为特征，可调控T细胞增殖分化。我们前期研究发现，舌鳞癌细胞通过肿瘤源性Foxp3调控TGF-β，在微环境中与Tregs细胞对话，使微环境向Tregs偏移，诱导免疫抑制，但与"Tregs-Th17"微环境存在差异；进一步研究发现，舌鳞癌IL-10表达上升，存在CD19+淋巴细胞浸润，提示Bregs可能在舌鳞癌微环境中发挥作用。据此我们率先提出，Bregs通过影响Tregs-Th17炎性微环境调控舌鳞癌间质纤维化。拟首先分析间质纤维化对舌鳞癌发生发展的影响，然后在信号通路、细胞因子网络、细胞接触作用、基因敲除小鼠等水平阐明Bregs在舌鳞癌炎性微环境与间质纤维化之间的调控机制，为舌鳞癌生物治疗提供实验及理论依据。

肿瘤微环境中慢性炎症浸润与间质纤维化同时存在，相互影响，其具体的作用机制未明。本研究在分析舌鳞癌微环境中间质纤维化及慢性炎症状态的基础上探讨间质纤维化、Bregs分布及数量与舌鳞癌患者临床病理特征及总生存率的关系；进而探讨慢性炎性细胞与肿瘤相关成纤维细胞的相互作用机制，以及它们共同作用下对舌鳞癌发生发展的影响。结果发现：①舌鳞癌间质微环境中，CAF、CF与间质浸润的CD19+B淋巴细胞同时存在；CAF、CF的浸润程度与肿瘤T分期相关，CD19+B细胞的浸润与患者的总生存率相关; ②与NF相比，CAF具有更强的迁移能力、合成分泌胶原能力、及分泌RANTES与TGF-β能力；慢性炎性细胞可通过直接的细胞-细胞接触及分泌可溶性介质刺激CAF及NF合成分泌胶原及多种细胞因子、趋化因子；TGF-β刺激仅可提高CAF MMP9及α-SMA表达，而对其胶原分泌能力无明显影响，且抑制其炎性细胞因子、趋化因子的合成分泌能力；CAF刺激慢性炎性细胞存活；③CAF及外周血PBMC共同刺激能促进舌鳞癌的增殖、迁移及侵袭能力; ④Bregs 通过减弱T细胞对肿瘤生长和转移的抑制而发挥免疫抑制作用；⑤在舌鳞癌环境中显著增加的Bregs通过分泌IL-10和细胞接触诱导静息T细胞向Tregs分化，并改变细胞因子平衡。