Tanreqing suppresses the proliferation and migration of non-small cell lung cancer cells by mediating the inactivation of the HIF1α signaling pathway via exosomal circ-WDR78

Circular RNAs (circRNAs) have emerged as regulators of cancer progression, including non-small cell lung cancer (NSCLC). Tanreqing (TRQ), a traditional Chinese medicine, is used clinically for respiratory diseases. RT-qPCR quantified circ-WDR78 expression in NSCLC cells. Cell growth, apoptosis, invasion, and migration were assessed by functional assays. RNA-binding protein immunoprecipitation (RIP), luciferase reporter, and RNA pull-down assays determined the competing endogenous RNA (ceRNA) network of circ-WDR78. The interaction between HIF1α and CD274 (PD-L1) promoter was analyzed by chromatin immunoprecipitation (ChIP). Circ-WDR78 expression was up-regulated in TRQ-treated NSCLC cells. Functionally, circ-WDR78 exhibited anti-tumor effects in these cells. Additionally, circ-WDR78 could also induce reactive oxygen species (ROS) accumulation by down-regulating HIF1α expression, promoting autophagy. Mechanistically, circ-WDR78 destabilizes HIF1α <i>via</i> the miR-1265/FBXW8 axis. TRQ-induced exosome secretion from NSCLC cells inhibits PD-L1 expression, preventing immune escape. We found that TRQ-treated NSCLC cells secrete exosomes to transmit circ-WDR78 to untreated NSCLC cells, inhibiting the malignancy of recipient tumor cells. In conclusion, TRQ inhibits NSCLC cell proliferation, invasion, and migration through exosomal circ-WDR78-mediated inactivation of the HIF1α signaling pathway, providing potential insight into TRQ injection for NSCLC treatment.

环形RNA（circRNAs）已被证实是包括非小细胞肺癌（NSCLC）在内的多种癌症进展的调控因子。痰热清（TRQ）作为一款传统中药，在临床中被用于治疗呼吸系统疾病。本研究采用实时定量聚合酶链反应（RT-qPCR）检测非小细胞肺癌细胞中circ-WDR78的表达水平，通过功能实验评估细胞增殖、凋亡、侵袭及迁移能力；利用RNA结合蛋白免疫沉淀（RIP）、荧光素酶报告基因及RNA下拉实验，明确circ-WDR78的内源竞争RNA（ceRNA）调控网络；采用染色质免疫沉淀（ChIP）实验分析缺氧诱导因子1α（HIF1α）与CD274（PD-L1）启动子的结合互作。经痰热清处理的非小细胞肺癌细胞中，circ-WDR78的表达水平显著上调。功能层面上，circ-WDR78在该类细胞中发挥抗肿瘤作用。此外，circ-WDR78可通过下调HIF1α的表达诱导活性氧（ROS）积累，进而促进细胞自噬。机制层面上，circ-WDR78通过miR-1265/FBXW8轴降低HIF1α的稳定性。痰热清诱导非小细胞肺癌细胞分泌的外泌体可抑制PD-L1的表达，从而阻断肿瘤免疫逃逸。本研究发现，经痰热清处理的非小细胞肺癌细胞可通过分泌外泌体将circ-WDR78传递至未处理的非小细胞肺癌细胞，从而抑制受体肿瘤细胞的恶性表型。综上，痰热清可通过外泌体携带的circ-WDR78介导HIF1α信号通路失活，从而抑制非小细胞肺癌细胞的增殖、侵袭与迁移，为痰热清注射液用于非小细胞肺癌的临床治疗提供了潜在的理论依据。