CircRNA SMARCC1 Sponges MiR-140-3p to Regulate Cell Progression in Colorectal Cancer

Our objective was to investigate the effect of circSMARCC1 on the developmental and biological behavior of colorectal cancer (CRC).

The expression of circSAMRCC1 and miR-140-3p in CRC tissues and cell lines (SW620, HCT116, HT29 and SW480) and a normal cell line (NCM460) was detected using qRT-PCR. The expression levels of circSMARCC1 and its linear subtype were detected. Fluorescence in situ hybridization was performed for the evaluation of the localization of circSAMRCC1 and miR-140-3p in the SW620 cell line. The effects of circSAMRCC1 and miR-140-3p on cell proliferation were investigated using CCK8 and colony formation assays, respectively. The effects of circSAMRCC1 and miR-140-3p on cell migration and invasion were determined using Transwell assay. The binding relationship between circSMARCC1 and miR-140-3p was further assessed by bioinformatics, ChIRP analysis and double luciferase reporter assay.

The expression of circSAMRCC1 in the CRC tissues and four cell lines is significantly increased, and circSMARCC1 and miR-140-3p are negatively correlated with expression level in the tissue. The downregulation of circSMARCC1 decreased CRC cell viability and suppressed metastasis in vitro and Inhibition of protein (MMP-2, MMP-9, VEGF) expression. miR-140-3p is downregulated in CRC tissues; miR-140-3p mimics inhibited SW620 cell viability, migration and invasion, and miR-140-3p inhibitors reversed the the effect of circSMARCC1 downregulation on cell proliferation, migration and invasion in CRC cells.

circSMARCC1 competitively combined with miR-140-3p and functioned through a circSMARCC1/miR-140-3p/MMPs axis as a CRC carcinogen, demonstrating its potential as a biomarker for CRC treatment.