TLR3信号通路活化逆转索拉非尼治疗肝癌引起的NK细胞免疫抑制的机制研究

Sorafenib was the standard molecularly targeted agent approved for treating advanced HCC, however, its efficacy is only moderate. Moreover, some off-target effects of sorafenib have been found, including the direct and indirect protumor effects and some immunosuppressive property. Therefore, it is desirable to explore other treatment modalities that can be applied in combination with sorafenib to increase its efficacy in patients with HCC. Our previous study also demonstrated the direct inhibitory effect of sorafenib on NK cells, which was attributed to the blocking of AKT and ERK phosphorylation. Our previous study also found TLR3 agonist polyinosinic-Polycytidilic acid (Poly I:C) cloud inhibit the growth and metastasis of HCC with low expression of TLR3, which was mediated by the activation of NK cells directly. In this study, we aim to investigate the role of TLR3 signaling in the reversal effect on suppression of NK Cells induced by sorafenib in the treatment of HCC and explore the underlying mechanism. We hope the research will provide new theoretical support for exploring other potent adjuvant which can activate NK cells in order to enhance the effect of sorafenib in the treatment of HCC.

索拉非尼是目前晚期肝癌的标准治疗药物，但其疗效有限且具有某些不足，包括直接和间接地促进肿瘤侵袭转移及抑制肿瘤免疫。因此，如何弥补其不足以增强其疗效是一项较有临床前景的课题。本课题前期研究发现索拉非尼治疗肝癌的同时具有抑制机体NK细胞免疫的负面作用。前期动物实验显示TLR3的激活配体Poly(I:C)可明显抑制低表达TLR3的肝癌生长及转移，主要跟激活NK细胞的杀伤活性有关。本课题拟在前期研究基础上，探讨TLR3的激活是否能够逆转索拉非尼治疗肝癌时引起的NK细胞免疫抑制的不利作用，并从NF-κB通路方面研究其相关分子作用机制，为今后开发TLR3的活化免疫佐剂，增强索拉非尼的肝癌治疗效果提供理论支持。

前期研究发现索拉非尼治疗肝癌的同时具有抑制机体NK细胞免疫的负面作用。本课题进一步研究TLR3受体激动剂Poly(I:C)是否能够一定程度逆转索拉非尼抑制NK细胞的负面作用。Poly(I:C)联合索拉非尼治疗荷肝癌小鼠能够起到协同作用，进一步抑制肿瘤的生长及转移，延长小鼠生存期。联合Poly(I:C)能够减弱索拉非尼引起的NK细胞数量减少及杀伤功能抑制。索拉非尼联合Poly(I:C)组小鼠尾静脉注射肝癌细胞，小鼠肺转移瘤较单用索拉非尼组明显减少。免疫磁珠分选小鼠NK细胞，Poly(I:C)能够增强NK细胞的杀伤功能，联合索拉非尼能够某种程度逆转其NK细胞抑制作用。Western blotting进一步探讨其分子机制，Poly(I:C)能够增加IκB磷酸化水平，同时明显减弱索拉非尼抑制Erk磷酸化水平的作用，这可能是TLR3受体激动剂Poly(I:C) 逆转索拉非尼NK细胞免疫抑制的分子机制。综合上述研究结果，本研究为今后开发TLR3的活化免疫佐剂，增强索拉非尼治疗肝癌的疗效提供新的理论支持。本项目资助发表SCI论文三篇，待发表SCI一篇。培养硕士2人。项目投入经费23万元，支出18.8万元。各项支出基本与预算相符。剩余经费4.2万元。剩余经费计划用于本项目研究后续支出。