Hsa_circ_0006677 regulates special AT-rich binding protein-2-mediated tumor-suppressive effect via functioning as a miR-1245a sponge in non-small cell lung cancer

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 via 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.Communicated by Ramaswamy H. Sarma.

Long noncoding RNA ArfGAP with RhoGAP domain, ankyrin repeat and PH domain 1 antisense RNA 1 recruits enhancer of zeste 2 polycomb repressive complex 2 subunit to promote the proliferation, migration and invasion of lung adenocarcinoma cells

The detailed function of ARAP1-AS1, the antisense RNA of Arf-GAP with Rho-GAP domain, ANK repeat and PH domain-containing protein 1 (ARAP1), in lung adenocarcinoma (LUAD) has not been clearly elucidated and required further investigation. Our study is committed to exploring the role of ARAP1-AS1 in LUAD. Gene expression in LUAD was measured by real-time quantitative polymerase-chain reaction (RT-qPCR). The influence of ARAP1-AS1 on LUAD cell malignant behaviors was evaluated by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, colony formation assay, Transwell invasion assay and wound healing assay. Subcellular fractionation assay detected the cellular localization of ARAP1-AS1 in LUAD. The protein levels were subjected to western blotting. RNA immunoprecipitation (RIP) and luciferase reporter assay were employed to verify the interaction between ARAP1-AS1, ARAP1 and enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2). Our investigation identified that ARAP1-AS1 was upregulated in LUAD cells and tissues. ARAP1-AS1 silencing repressed LUAD cell growth and migration. Furthermore, ARAP1-AS1 knockdown altered the expression of its sense mRNA, ARAP1. ARAP1-AS1 could recruit EZH2 to inhibit ARAP1 expression. Additionally, the downregulation of ARAP1 reversed ARAP1-AS1 downregulation-induced repression of cell growth and migration in LUAD. In conclusion, ARAP1-AS1 recruited EZH2 to silence ARAP1, facilitating cell proliferation, migration and invasion in LUAD. Our study demonstrated the possibility of ARAP1-AS1 to be a novel therapeutic target for LUAD.