Ning Zhao

circ-NOLC1 inhibits the development of cervical cancer by regulating miR-330-5p-PALM signaling axis

Abstract Background Recent studies have increasingly demonstrated that circular RNAs (circRNAs) play significant roles in the occurrence and progression of cervical cancer (CC). In CC, circRNAs act as ceRNAs by sponging miRNAs to regulate genes associated with proliferation, migration, and apoptosis, exhibiting both promoting and inhibiting effects on tumor progression. The aim of this study was to clarify the role of hsa_circ_0019686 (named circ-NOLC1) in CC. Methods By conducting an online GEO2R analysis of the expression profile GSE113696 in the GEO database, circ-NOLC1 was selected. The expression levels of circ-NOLC1 in CC cell lines were measured using real-time quantitative PCR (RT-qPCR). The role of circ-NOLC1 in CC was validated through both in vitro and in vivo gain-of-function assays. Bioinformatic analysis, combined with luciferase reporter and RNA Immunoprecipitation (RIP) assays, confirmed that circ-NOLC1 acts as a sponge for miR-330-5p and regulates the expression of paralemmin-1 (PALM). The role of the circ-NOLC1-miR-330-5p-PALM signaling axis in CC was elucidated through the rescue experiments. Relative gene expression levels were measured using RT-qPCR, while relative protein levels were assessed through immunohistochemistry (IHC). CCK-8, wound healing, Transwell, and flow cytometry assays were employed to evaluate CC cell proliferation, migration, and invasion, respectively. Results The expression levels of circ-NOLC1 were dramatically downregulated in CC cells (P < 0.001). Up-regulation of circ-NOLC1 significantly inhibited cell proliferation (P < 0.001), migration (P < 0.01) and invasion (P < 0.01), while promoting cell apoptosis (P < 0.001). In vivo studies showed that up-regulation of circ-NOLC1 suppressed tumor growth (tumor volume: P < 0.001; tumor weight: P < 0.01). Additionally, miR-330-5p was found to be up-regulated in CC (P < 0.001), whereas PALM was downregulated in CC (P < 0.001). The up-regulation of circ-NOLC1 inhibited the expression of miR-330-5p (P < 0.001) and enhanced the expression of PALM (P < 0.001). Rescue experiments further demonstrated that the up-regulation of circ-NOLC1 inhibited CC cell proliferation (P < 0.001), migration (P < 0.001), invasion (P < 0.001), while promoting apoptosis (P < 0.001) through the regulation of the miR-330-5p-PALM pathway. Conclusion The circ-NOLC1 inhibits CC development through regulating the miR-330-5p-PALM signaling axis. This finding reveals a novel mechanism and identifies potential therapeutic targets, emphasizing the necessity for further regulatory studies and clinical validation.

HPV18 E6/E7 activates Ca2+ influx to promote the malignant progression of cervical cancer by inhibiting Ca2+ binding protein 1 expression

AbstractMounting studies have shown that the oncoproteins E6 and E7 encoded by the human papillomavirus (HPV) genome are essential in HPV‐induced cervical cancer (CC). Ca2+ binding protein 1 (CABP1), a downstream target of HPV18‐positive HeLa cells that interferes with E6/E7 expression, was identified through screening the GEO Database (GSE6926). It was confirmed to be down‐regulated in CC through TCGA prediction and in vitro detection. Subsequent in vitro experiments revealed that knocking down E6/E7 inhibited cell proliferation, migration, and invasion, whereas knocking down CABP1 promoted these processes. Simultaneously knocking down CABP1 reversed these effects. Additionally, the results were validated in vivo. Previous studies have indicated that CABP1 can regulate Ca2+ channels, influencing Ca2+ influx and tumor progression. In this study, it was observed that knocking down CABP1 enhanced Ca2+ inflow, as demonstrated by flow cytometry and confocal microscopy. Knocking down E6/E7 inhibited these processes, whereas simultaneously knocking down E6/E7 and CABP1 restored the inhibitory effect of knocking down E6/E7 on Ca2+ inflow. To further elucidate that E6/E7 promotes CC progression by inhibiting CABP1 expression and activating Ca2+ influx, BAPTA/AM treatment was administered during CABP1 knockdown. It was discovered that Ca2+ chelation could reverse the effect of CABP1 knockdown on CC cells. In conclusion, our results offer a novel target for the diagnosis and treatment of HPV‐induced CC.