整合素β6激活NLPR3促进2型固有淋巴细胞增殖活化在肝癌热消融后复发中的作用和机制

热消融为小肝癌的一线根治性疗法，但治疗后高复发率是亟待解决的临床问题。申请人前期发现消融后复发临床标本及小鼠消融灶旁肝癌细胞整合素β6明显上调，免疫抑制性2型固有淋巴细胞ILC2显著增多。二者之间是否存在关联及如何参与消融后复发，尚不明确。进一步研究发现，敲除肝癌细胞β6可有效降低消融后肝内复发，且该作用是通过下调ILC2数目从而逆转免疫抑制微环境实现。此外，β6可促进热刺激下肝癌细胞NLPR3活化及IL1β分泌，进而诱导ILC2增殖和产生IL13。据此提出假说：肝癌细胞β6通过激活NLPR3-IL1β通路，促进ILC2介导的免疫抑制，最终导致消融后复发。本项目拟多层次阐明β6在消融后复发过程中对肝癌细胞和微环境相互作用的调控，揭示β6-NLRP3-ILC2介导的消融后免疫抑制机制，为采用靶向β6的免疫治疗策略来突破肝癌消融后高复发率的瓶颈提供科学依据。

Radiofrequency ablation (RFA) is the first-line therapy of early-stage hepatocellular carcinoma (HCC), but the 2-year recurrence rate after RFA is 50%. Exploring an effective way to prevent and treat the recurrence after RFA is urgent needed clinically. The immune system imbalance of tumor microenvironment is a critical regulator of HCC recurrence after RFA. Innate lymphoid cells (ILCs) is proven to be one of the most important immune cells in tumor microenvironment, which could induce immune imbalance and eventually lead to recurrence after RFA. The preliminary data indicated that the number of group 2 ILC (ILC2) significantly increased in clinically recurrent tumor specimens and in tissues adjacent to ablative area in mouse model, which had a positive relationship with the increasing of integrin β6 in the corresponding clinical and mice samples. Knockdown of β6 could reduce the number of ILC2, thereby reversing the immunosuppressive microenvironment, and finally result in decreasing the recurrence rate after RFA in mice. Furthermore, in vitro experiment, we found that β6 can activate NLPR3, one type of inflammasome, and interlukin 1β (IL1β), which can lead to ILC2 proliferation and activation (namely IL13 secretion). Based on these results, we presume that thermal stimulation promotes integrin β6 in HCC cells, which can activate NLPR3-IL1β signal pathway. IL1β then acts on ILC2 and results in its proliferation and secretion of IL13. After that, IL13 induces immune imbalance in tumor microenvironment which promotes recurrence after RFA. We carry out this study to illustrate the mechanisms of activation of NLPR3 by β6, the mechanisms of activation of ILC2 by IL1β, the mechanisms how IL13 regulating immune cell, and the translational therapeutic role of β6 after RFA. We believe the study would provide solid scientific evidence on the prevention and treatment of HCC recurrence after RFA.