hsa_circ_0000231 promotes colorectal cancer cell growth through upregulation of CCND2 by IGF2BP3/miR-375 dual pathway
Abstract Background and aim Circular RNAs (circRNAs) have emerged as vital regulators of the initiation and progression of diverse kinds of human cancers. This study aimed to investigate the role of circRNAs in colorectal cancer (CRC). Methods The expression profiles of circRNAs in five pairs of CRC tissues and adjacent normal tissues were analyzed using microarray. Quantitative real-time polymerase chain reaction, in situ hybridization, and BaseScope Assay were used to determine the level and prognostic values of hsa_circ_0000231. Then, in vitro and in vivo functional experiments were performed to investigate the effects of hsa_circ_0000231 on cell proliferation. Mechanistically, fluorescence in situ hybridization, dual-luciferase reporter assay, and RNA pull-down and RNA immunoprecipitation experiments were performed to confirm the interaction between hsa_circ_0000231 and Insulin-like growth factor 2 mRNA-binding protein 3(IGF2BP3) or has_miR-375. Results The expression of hsa_circ_0000231 was upregulated in CRC primary tissues, which indicated poor prognosis of patients with CRC. The results demonstrated that hsa_circ_0000231 could promote CRC cell proliferation as well as tumorigenesis in vitro and in vivo. The mechanistic analysis showed that hsa_circ_0000231 might, on the one hand, act as a competing endogenous RNA of miR-375 to promote cyclin D2 (CCND2) and, on the other hand, bind to the IGF2BP3 protein to prevent CCND2 degradation. Conclusion The findings suggested that hsa_circ_0000231 facilitated CRC progression by sponging miR-375 or binding to IGF2BP3 to modulate CCND2, implying that has_circ_0000231 might be a potential new diagnostic and therapeutic biomarker of CRC.