Mol Carcinog. 2020 Oct 30. doi: 10.1002/mc.23259. Online ahead of print.
This study aimed to investigate the role of circ0106714-miR-942-5p-discs large homolog 2 (DLG2), a novel interactome, in colorectal cancer (CRC). Circ0106714 was found to be the most significantly downregulated circular RNA in CRC using a bioinformatics method, and we researched whether the ability of circ0106714 to sponge miR-942-5p and release DLG2 could affect CRC development via Hippo-YES-associated protein (YAP) signaling. We first employed qRT-PCR and immunoblotting to detect messenger RNA
(mRNA) and protein expression, respectively. Live imaging of mice tumor xenografts was then conducted to study the effect of circ0106714 on tumor progression in vivo. Reporter gene assays were subsequently conducted to verify the predicted targeting relationship between circ0106714, miR-942-5p, and DLG2 mRNA in SW480 and HCT116 cell lines. As well as using flow cytometry for both apoptosis and cell cycle profile analyses, CCK-8 and clone foci formation assays were performed to assess cell survival. Wound healing assay and transwell invasion assay were later carried out to evaluate the migration and invasion of the cell lines. Findings revealed that circ0106714 and DLG2 were significantly downregulated, while miR-942-5p was significantly upregulated in human CRC tissues and cell lines. However, circ0106714 upregulation significantly suppressed tumor progression in vivo and inhibited the malignancy phenotypes of tumor cells in vitro by targeting miR-942-5p. Also discovered in this research was that miR-942-5p could directly target DLG2 mRNA, thus enhancing the malignancy phenotypes of CRC cells. We even found that DLG2 overexpression resulted in enhanced phosphorylation of YAP, a critical downstream effector of DLG2. This downstream effector was demonstrated to have a tumor-suppressive capacity in CRC cell lines. In sum, circ0106714 could suppress CRC by sponging miR-942-5p and releasing DLG2, thus promoting YAP phosphorylation.