CircRNF10-DHX15 interaction suppressed breast cancer progression by antagonizing DHX15-NF-κB p65 positive feedback loop

BACKGROUND

Breast cancer (BC) is a common threat to women. The continuous activation of nuclear factor kappa B (NF-κB) signaling pathway contributes to the development of BC. This study aimed to investigate the role of a circular RNA (circRNF10) in BC progression and regulating NF-κB signaling pathway.

METHODS

Bioinformatics analysis, RT-qPCR, subcellular fractionation, FISH, RNase R treatment, and actinomycin D assay were used to explore the expression and characteristics of circRNF10 in BC. The biological functions of circRNF10 in BC were analyzed by MTT assay, colony formation assay, wound healing assay, and Transwell assay. RNA pulldown and RIP assay were used to identify the interaction between circRNF10 and DEAH (Asp-Glu-Ala-His) box helicase 15 (DHX15). The impact of circRNF10-DHX15 interaction on NF-κB signaling pathway was explored by western blot, IF, and co-IP. Furthermore, dual-luciferase reporter assay, ChIP, and EMSA were performed to assess the effect of NF-κB p65 on DHX15 transcription.

RESULTS

CircRNF10 was downregulated in BC, and lower expression of circRNF10 was related to poor prognosis of patients with BC. CircRNF10 inhibited the proliferation and migration of BC. Mechanically, circRNF10-DHX15 interaction sequestered DHX15 from NF-κB p65, thereby inhibiting the activation of NF-κB signaling pathway. On the other hand, NF-κB p65 enhanced DHX15 transcription by binding to the promoter of DHX15. Altogether, circRNF10 impaired the DHX15-NF-κB p65 positive feedback loop and suppressed the progression of BC.

CONCLUSION

CircRNF10-DHX15 interaction suppressed the DHX15-NF-κB p65 positive feedback loop, thereby inhibiting BC progression. These findings provide new insights in the continuous activation of NF-κB signaling pathway and raised potential therapeutic approach for BC treatment.

circRNF10 Regulates Tumorigenic Properties and Natural Killer Cell-Mediated Cytotoxicity against Breast Cancer through the miR-934/PTEN/PI3k-Akt Axis

Circular RNA (circRNA), a type of non-coding RNA, has received a great deal of attention with regard to the initiation and progression of tumors. However, the molecular mechanism and function of circRNAs in breast cancer (BC) remain unclear. In the current study, we discovered that hsa_circ_0028899 (also called circRNF10) was significantly reduced in BC tissues, and a higher level of circRNF10 was markedly related to a favorable prognosis. The results of CCK8, colony formation, Transwell, ELISA, and NK cell-mediated cytotoxicity assays indicated that increased circRNF10 expression could significantly repress the proliferation, invasion, and migration of BC cells and enhance the killing efficiency of NK cells against BC cells. According to these biological functions, the possible role and molecular mechanism of circRNF10 in BC cells were further investigated. We used bioinformatics prediction tools to predict circRNF10-bound miRNAs, which were verified by many experimental studies, including FISH, luciferase reporter assays, RIP, and Western blots. These data suggest that circRNF10 serves as a molecular sponge for miR-934 to further regulate PTEN expression and PI3k/Akt/MICA signaling in vitro and tumor growth in vivo. Altogether, these findings reveal that circRNF10 functions as a novel anti-oncogene in BC via sponging miR-934 and suppressing the PI3K/Akt/MICA pathway.