掌叶半夏脂溶性提取物PE活化树突状细胞增强Th1型细胞免疫抑制宫颈癌生长的分子机制

CD4+ type-1 T helper cell (Th1)-mediated immune response is suppressed in patients with cervical cancer. Some traditional Chinese medicine has preventive and therapeutic effect on cancers by upregulating the human immune system. Previous clinical studies have confirmed that treatment of Pinellia pedatisecta Schott on cervical cancer is safe and effective. Our results have shown the inhibitory effects of a lipid-soluble extract from Pinellia pedatisecta Schott (PE) on subcutaneous xenografts in mice through up-regulation of IL-12, IFN-γ, and the proportion of Th1 cells in vivo. Hereby, we speculate that PE can have antineoplastic effect on cervical cancer by inducing CD4+ T cells to differentiate into Th1. This project, based on type-1 polarization, the role of PE in strengthening body immunity, its related mechanism was studied in vivo, and vitro, using subcutaneous xenografts in C57BL/6 mice of HPV positive TC-1 cells by the techniques of current immunology and molecular biology, aimed to understand the mechanism of action on how PE can enhance immunity. Its potential mechanism of action may involve inhibition of SOCS1 expression, which releases its inhibition of IFNγ-STAT1 pathway, then promotes the secretion of IL-12 by DCs to activate the JAK2-STAT4 signaling pathway within T cells, and finally induces Th0 cells to Th1 differentiation to enhance the antitumor cell immune responses. The success of this project will rich the theory of traditional Chinese medicine on cancer therapy.

宫颈癌患者CD4+Th1细胞免疫功能减弱，中药可通过调节机体免疫防治肿瘤。临床研究证实传统中药掌叶半夏治疗宫颈癌安全、有效。课题组发现，掌叶半夏提取物PE能够抑制荷瘤小鼠肿瘤生长，Th1型细胞比例升高、Th2型细胞比例下降，效应细胞因子IL-12、IFN-γ升高。据此推测，PE可通过诱导CD4+T细胞向Th1型分化治疗宫颈癌。本项目以PE促进荷瘤机体细胞免疫向Th1型偏移为切入点，采用野生型C57BL/6小鼠HPV阳性TC-1细胞皮下移植瘤模型为研究对象，运用现代免疫学和分子生物学技术，通过体内、外实验深入探讨PE促进机体免疫向Th1型分化治疗宫颈癌的潜在机制之一是通过抑制SOCS1表达，解除其对IFNγ-STAT1信号通路的抑制作用，促进DCs分泌IL-12，激活T细胞内JAK2-STAT4信号通路，诱导Th0细胞向Th1分化，增强机体抗肿瘤细胞免疫效应。丰富中药抗肿瘤免疫理论。

宫颈癌是全球女性癌症死亡的第二大恶性肿瘤，目前宫颈癌的治疗方式包括手术、放疗、化疗，仍存在治疗效果欠佳、毒副作用大、高复发率和转移率等诸多问题。在西医治疗宫颈癌面临巨大挑战时，我国传统中医中药显著的临床疗效受到越来越多的关注。本课题组自上世纪70年代以来长期聚焦于临床宫颈癌的治疗，通过多年的临床及基础实验研究发现，中药掌叶半夏（pinellia pedatisecta schott）及其活性成分提取物（pinellia pedatisecta schott extract, PE）具有确切的抗肿瘤效果，毒性反应低，同时可协同化疗药物顺铂联合对抗肿瘤进展。中医学认为，“正气存内，邪不可干”，癌症的发生是由于体内平衡破坏、阴阳交时正邪（宿主与肿瘤）相争的过程，肿瘤免疫微环境即是阴阳相争、平衡紊乱破坏的主要场所。研究表明，多种中药具有免疫增益作用，临床应用广泛，可通过提高机体的免疫监视功能在恶性肿瘤的治疗中起到辅助作用。因此，本课题组同时关注PE能否增强患癌机体的抗肿瘤免疫功能，前期研究发现，PE能够调节荷瘤小鼠辅助性T细胞的分化。树突状细胞（Dendritic cells, DCs）作为目前已知功能最强的专职抗原提呈细胞，是启动、激活、维持和调控抗肿瘤适应性免疫的关键。因此，本研究将对宫颈癌中树突状细胞在中药PE重激活抗肿瘤免疫中的临床意义与作用机制进行深入探索。通过原代细胞体外实验、小鼠体内实验及人宫颈癌样本离体实验等多种实验模型，本研究证实：宫颈癌微环境下DCs处于低功能的免疫耐受状态，PE可抑制细胞内异常高表达的SOCS1蛋白进一步激活JAK/STAT信号通路，通过该机制诱导肿瘤环境下低功能状态的树突状细胞向成熟活化表型转化，从而有效促进抗肿瘤CD4+及CD8+T细胞的增殖、Th1和CTLs亚群分化、及免疫杀伤效应功能的发挥，强化免疫监视作用。鉴于PE在宫颈癌中发挥直接抑瘤作用及免疫增强效果，并且无严重毒性作用，可以认为PE是一种可应用于未来宫颈癌临床治疗的潜在药物或辅助佐剂。