Colorectal Cancer

Circ_0003266[Circular RNA]

miR-503-5p[miRNA]

PDCD4[mRNA]

CRC tissues / adjacent tissues and cell lines

Homo sapiens (human)

BMC Cancer. 2021 Mar 16;21(1):284. doi: 10.1186/s12885-021-07997-0.

Circ_0003266 sponges miR-503-5p to suppress colorectal cancer progression via regulating PDCD4 expression.

Dual-luciferase reporter assay;qRT-PCR;Western blot;Flow Cytometry assay;Luciferase reporter assay;

BACKGROUND: Circular RNAs (circRNAs) feature prominently in tumor progression. However, the biological function and molecular mechanism of circ_0003266 in colorectal cancer (CRC) require further investigation. METHODS: Circ_0003266 expression in 46 pairs CRC tissues / adjacent tissues, and CRC cell lines was detected by quantitative real-time polymerase chain reaction (qRT-PCR); after circ_0003266 was overexpressed or knocked down in CRC cells, cell proliferation, apoptosis, migration, and invasion were evaluated by the cell counting kit-8 (CCK-8), flow cytometry, and Transwell assays, respectively; the interaction among circ_0003266, miR-503-5p, and programmed cell death 4 (PDCD4) was confirmed using bioinformatics analysis and dual-luciferase reporter assay; PDCD4 protein expression in CRC cells was quantified using Western blot. RESULTS: Circ_0003266 was significantly lowly expressed in CRC tissues and cell lines. Circ_0003266 overexpression markedly repressed CRC cell proliferation, migration, and invasion, and accelerated the cell apoptosis, but its overexpression promoted the malignant phenotypes of CRC cells. PDCD4 was a direct target of miR-503-5p and circ_0003266 promoted PDCD4 expression by competitively sponging miR-503-5p. CONCLUSION: Circ_0003266 suppresses the CRC progression via sponging miR-503-5p and regulating PDCD4 expressions, which suggests that circ_0003266 may serve as a novel target for the treatment of CRC.