微波消融经INF-γ介导非小细胞肺癌PD-L1表达上调的分子机制研究

Chemotherapy for advanced non-small cell lung cancer（NSCLC）has reached the plateau. Immunotherapy and microwave ablation (MWA) have been widely applied in the treatment of NSCLC. MWA has the dual effects of enhancing and inhibiting immunity. However, the effect of microwave ablation on the programmed death receptor ligand-1 (PD-L1) is not yet clear. Our previous study showed the update of PD-L1 expression in primary tumor sites when oligometastatic NSCLC patients treated with MWA for the metastatic tumor sites, accompanied by the update of both gamma interferon (INF-γ) and CD8 + tumor infiltrating lymphocytes (TIL). However, the definite mechanism of microwave ablation to update PD-L1 expression is not yet clear. The aim of this study was to verify that microwave ablation induced the update of PD-L1 expression in NSCLC cell lines, transplanted tumor models and large sample oligometastatic NSCLC patients; Moreover, to demonstrate that INF-γ was the key in the update of PD-L1 expression by enhancing or interfering with INF-γ combined with microwave ablation; to determinate that INF-γ mediates PD-L1 expression through P3K/AKT and JAK-STAT-3 signal pathways by combined AKT and STAT-3 inhibitors with microwave ablation; to verify that immunotherapy plus microwave ablation can overcome T cell immunosuppression induced by elevated PD-L1 expression. The study can provide theoretical basis for microwave ablation combined with immunotherapy.

进展期非小细胞肺癌化疗已达瓶颈期，免疫治疗及微波消融（MWA）应用日益广泛。微波消融具有增强与抑制免疫的双重作用。然而微波消融对程序性死亡受体配体1（PD-L1）影响尚不明确。我们前期研究发现非小细胞肺癌寡转移患者寡转移灶微波消融后原发灶PD-L1表达上调，伴γ干扰素（INF-γ）及CD8+肿瘤浸润淋巴细胞（TIL）增加。微波消融上调PD-L1表达的具体机制尚不明确。本研究旨在NSCLC细胞系、移植瘤模型及大样本NSCLC寡转移患者验证微波消融介导PD-L1表达上调；通过增强或干扰INF-γ联合微波消融确认INFγ在PD-L1表达上调中居于核心地位，通过AKT及STAT3抑制剂联合微波消融明确INF-γ通过PI3K/AKT及JAK-STAT3信号通路介导PD-L1表达；通过免疫抑制剂联合微波消融确认联合治疗可克服PD-L1表达上调所致T细胞免疫抑制。为微波消融联合免疫治疗奠定理论基础。

免疫治疗是进展期非小细胞肺癌的重要治疗手段，微波消融作为局部热消融治疗方式在肺癌中应用日益广泛。既往研究表明微波消融联合PD-1单抗具有协同作用，但具体机制尚不明确。本研究旨在明确INF-γ介导的PD-L1表达升高在微波消融联合免疫治疗中的协同作用。研究表明PD-L1表达存在明显异质性，以PD-L1 TPS表达≥5%与≥1%为界，消融前后PD-L1表达的不一致性分别为19.4%与22.6%，未能验证既往研究中微波消融可介导PD-L1表达上调等现象，因此未再进行移植瘤模型、细胞学验证及相关机制探讨。MWA后1月INF-γ由消融前3.5pg/ml升高至5.3pg/ml，提示IFN-γ可介导微波消融的免疫增效作用。微波消融联合PD-1单抗单药或联合治疗进展期非小细胞肺癌，客观缓解率（ORR）为29.9%，无进展生存时间（PFS）为11.8个月。微波消融联合PD-1单抗单药治疗进展期非小细胞肺癌的回顾性多中心研究，其ORR为32.4%，PFS分别为6.7月。微波消融联合PD-1单抗对比PD-1单抗单药后线治疗进展期非小细胞肺癌，ORR分别为38.2%与14.7%（p=0.028），PFS分别为8.7个月（95%CI 7.7-9.6) 与. 3.9个月[95% CI 3.1-4.7], P=0.045。该研究证实微波消融可介导INF-γ表达上调，并发挥微波消融联合PD-1单抗的协同作用。上述研究为微波消融联合PD-1单抗提供了理论支持。