炎性微环境中Foxo3诱导可逆性去分化调控舌鳞癌免疫逃逸的作用机制

The latest research demonstrates that tumor cells escape CTLs' recognition by inflammation-induced reversible dedifferentiation, but how does reversible dedifferentiation happen? Our previous study showed that transcription factor Foxo3 was expressed in tongue squamouse cell carcinoma (TSCC) cells, and the subcellular distribution was heterogeneous, which implicated a reversible translocation of Foxo3 in TSCC cells. Further research showed a promotion of Foxo3 nuclear translocation by environmental TNF-α, implicating that inflammatory microenvironment could regulate Foxo3 transcriptional regulation function. And we also revealed that subcellular distribution of Foxo3 correlated with TSCC cells differentiation.Based on these results, we propose that in the inflammatory microenvironment, dynamic subcellular translocation of Foxo3 regulates reversible dedifferentiation in TSCC cells to escape CTLs' recognition. At first, we work to identify the signaling pathway regulating Foxo3 subcellular distribution. Next we will construct point-mutation plasmids to build a Foxo3 subcellular translocation dynamic regulation model so that we can study the molecular mechanism of reversible dedifferentiation in TSCC cells. Then we will detect the recognition of dedifferentiated and differentiated TSCC cell by CTL. Based on the coming results, we will regulate the key mechanism that we find of reversible dedifferentiation in mice TSCC model to demonstrate the theory in vivo. We hope this study can reveal a new mechanism of TSCC immune-escape, then to raise a new promising target for TSCC molecular-targeting therapy.

最新发现，肿瘤细胞通过炎症诱导的可逆性去分化逃避CTL的识别与杀伤，但机制不明。本课题组前期研究发现，转录因子Foxo3表达于舌鳞癌细胞，其亚细胞空间分布呈异质性，Foxo3在舌鳞癌细胞中存在亚细胞分布转换；进一步研究发现，微环境TNF-α可促进Foxo3向核内转移，提示炎性微环境调控Foxo3的转录功能；并且证明，Foxo3亚细胞分布与舌鳞癌分化相关。据此，本课题组率先提出：炎性微环境中，Foxo3通过亚细胞分布转换诱导可逆性去分化，调控舌鳞癌免疫逃逸。拟首先探讨炎性微环境调控Foxo3亚细胞分布的信号通路，进而利用点突变质粒建立Foxo3亚细胞分布调控模型，阐明Foxo3直接调控舌鳞癌细胞可逆性去分化的分子机制，在此基础上分析特异性CTL对发生可逆性去分化舌鳞癌细胞的识别及杀伤能力，结合体内实验，证明逆转免疫逃逸的抑瘤效果，为肿瘤免疫逃逸提供新的实验及理论依据，为舌鳞癌治疗提供新的靶点

转录因子Foxo3表达于舌鳞癌细胞，其亚细胞空间分布呈异质性，Foxo3在舌鳞癌细胞中存在亚细胞分布转换；肿瘤微环境中的炎性因子可促进Foxo3发生亚细胞定位的改变，并调控Foxo3的转录调控功能，进而影响舌鳞癌的分化，这可能与肿瘤细胞通过炎症诱导的可逆性去分化逃避CTL的识别与杀伤相关。本研究通过组织标本、舌鳞癌细胞系以及动物实验验证Foxo3a的表达量、磷酸化状态以及亚细胞定位对舌鳞癌分化程度的影响；并构建炎性微环境，研究炎性因子对舌鳞癌细胞分化的影响，分析Foxo3a及相应通路在其中的调控。.本研究首先在人舌鳞癌微环境证明Foxo3a表达与舌鳞癌细胞分化正相关；然后构建Foxo3a过表达及干扰细胞株，在体内外水平证实Foxo3a的表达量与肿瘤的分化程度相关性；诱导舌鳞癌细胞去分化，证明Foxo3a磷酸化状态和亚细胞定位对分化程度的调控作用，进一步证明PI3K/Akt通过调控Foxo3a对舌鳞癌细胞干性的影响。构建炎性微环境，证明IL-8、TGF-β、IL-6网络对Foxo3a磷酸化及舌鳞癌细胞干性的调控作用。