circCLK3 regulates colorectal cancer SW620 cell proliferation, migration, and invasion by targeting miR-654-5p

BACKGROUND

Recent studies have investigated the role of circular RNAs (circRNAs) as significant regulatory factors in the progression of multiple cancers, containing colorectal cancer (CRC). Nevertheless, the biological functions of circCLK3 in CRC and the underlying mechanisms by which it regulates CRC progression remain unclear.

AIM

To clarify the mechanism of circCLK3 regulating colorectal cancer SW620 cell proliferation, migration, and invasion.

METHODS

CRC tissues and adjacent tissues were collected, and the expression of circCLK3 and miR-654-5p was detected by qRT-PCR. SW620 cells were cultured in vitro and divided into the following groups: si-circCLK3 group, pcDNA-circCLK3 group, miR-654-5p group, si-circCLK3 + anti-miR-654-5p group, and corresponding negative control groups (si-NC group, pcDNA group, miR-NC group, and si-circCLK3 + anti-miR-NC group). CCK8 assay, colony formation test, scratch test, and Transwell test were used to detect cell proliferation, migration, and invasion. The interaction between circCLK3 and miR-654-5p was confirmed by dual-luciferase reporter assay. The protein expression of MMP-2 and MMP-9 was detected by Western blot.

RESULTS

circCLK3 expression was increased (P < 0.05), while miR-654-5p expression was decreased (P < 0.05) in CRC tissues. Cell viability, scratch healing rate, the protein levels of matrix metalloproteinase-2 (MMP-2) and MMP-9, the number of cell clones formed, and the number of invasive cells were decreased (P < 0.05) in the si-circCLK3 group. circCLK3 could negatively regulate the expression of miR-654-5p. Cell viability, scratch healing rate, the protein levels of MMP-2 and MMP-9, the number of cell clones formed and the number of invasive cells were decreased (P < 0.05) in the miR-654-5p group. Cell viability, scratch healing rate, the protein levels of MMP-2 and MMP-9, the number of cell clones formed, and the number of invasive cells were increased (P < 0.05) in the si-circCLK3 + anti-miR-654-5p group.

CONCLUSION

circCLK3 promotes CRC cell proliferation, migration, and invasion by targeting miR-654-5p.

Circular RNA circCLK3 promotes the progression of tongue squamous cell carcinoma via miR-455-5p/PARVA axis

A previous study has elucidated that circular RNA circCLK3 acts as an oncogenic gene in cervical cancer. However, the role and regulatory mechanism of circCLK3 in tongue squamous cell carcinoma (TSCC) remain unknown. Quantitative real-time PCR was used to examine targeted gene expression in different groups. Cell viability and proliferation were investigated by MTT and 5-ethynyl-2'-deoxyuridine assays. Cell migration and invasion were detected by Transwell assays, and cell apoptosis was measured by flow cytometry analysis. The interaction among genes was investigated using luciferase reporter assay, RNA pull-down assay, and RNA immunoprecipitation assay. In the present study, our findings revealed the upregulated expression of circCLK3 in TSCC tissues and cell lines. CircCLK3 knockdown suppressed cell proliferation, migration invasion, and induced cell cycle arrest at G0/G1 phase in TSCC. Moreover, circCLK3 acted as a molecular sponge for miR-455-5p. PARVA was the target gene of miR-455-5p. Furthermore, the negative correlation between expression of miR-455-5p and circCLK3 or PARVA in TSCC tissues was discovered. Rescue assays indicated that PARVA overexpression reversed the circCLK3 knockdown-mediated inhibitory effects on the progression of TSCC. In summary, circCLK3 exerts its carcinogenic effects on TSCC progression via absorbing miR-455-5p to upregulate PARVA, which expands our knowledge on the underlying mechanism of TSCC.