METHODS: The alteration of PD-L1 expression induced by niraparib in cervical cancer cells and its underlying mechanism were assessed by western blot and immunofluorescence and quantitative real-time polymerase chain reaction (qRT-PCR).The regulation of PTEN by KDM5A was confirmed using Chromatin immunoprecipitation (ChIP) assay and RNA interference. Analyzing the relationship between PD-L1 and immune effector molecules through searching online databases. Therapeutic efficacy of niraparib, PD-L1 blockade or combination was assessed in syngeneic tumor model. The changes of immune cells and cytokines in vivo was detected by immunohistochemistry (IHC) and qRT-PCR.
RESULTS: We found that niraparib upregulated PD-L1 expression and potentiated the antitumor effects of PD-L1 blockade in a murine cervical cancer model. Niraparib inhibited the Pten expression by increasing the abundance of KDM5A, which expanded PD-L1 abundance through activating the PI3K-AKT-S6K1 pathway. PD-L1 was positively correlated with immune effector molecules including TNF-α, IFN-γ, granzyme A and granzyme B based on biological information analysis. Niraparib increased the infiltration of CD8+ T cells and the level of IFN-γ, granzyme B in vivo.
CONCLUSIONS: Our findings demonstrates the regulation of niraparib on local immune microenvironment of cervical cancer, and provides theoretical basis for supporting the combination of PARPi and PD-L1 blockade as a potential treatment for cervical cancer.
方法:采用westernblot、免疫荧光和实时定量聚合酶链反应(qRT-PCR)检测尼拉帕尼诱导宫颈癌细胞PD-L1表达的改变及其机制。使用染色质免疫沉淀(ChIP)测定和RNA干扰证实了KDM5A对PTEN的调节。通过搜索在线数据库分析PD-L1与免疫效应分子之间的关系。尼拉帕尼的疗效,在同基因肿瘤模型中评估PD-L1阻断或组合。免疫组织化学(IHC)和qRT-PCR检测体内免疫细胞和细胞因子的变化。
结果:我们发现尼拉帕尼在小鼠宫颈癌模型中上调PD-L1表达并增强PD-L1阻断的抗肿瘤作用。尼拉帕尼通过增加KDM5A的丰度抑制Pten的表达,通过激活PI3K-AKT-S6K1途径扩大PD-L1的丰度。PD-L1与包括TNF-α在内的免疫效应分子呈正相关,IFN-γ,基于生物信息分析的颗粒酶A和颗粒酶B。尼拉帕尼增加了CD8+T细胞的浸润和IFN-γ的水平,颗粒酶B在体内。
结论:我们的研究结果表明尼拉帕尼对宫颈癌局部免疫微环境的调节作用,为支持PARPi联合PD-L1阻断作为宫颈癌潜在治疗提供了理论依据。