Circular RNA circ_0007142 regulates cell proliferation, apoptosis, migration and invasion via miR-455-5p/SGK1 axis in colorectal cancer.

Colorectal cancer (CRC) is a frequently diagnosed cancer worldwide. Accumulating researches suggested that circular RNA 0007142 (circ_0007142) contributed to the progression and initiation of CRC. However, the molecular mechanism of circ_0007142 in CRC needs further research. Levels of circ_0007142, microRNA-455-5p (miR-455-5p), and serum- and glucocorticoid-induced protein kinase 1 (SGK1) were identified by quantitative real-time PCR. Cell proliferation was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazol-3-ium bromide assay. Flow cytometry assay was used to detect cell apoptosis in SW480 and HCT116 cells. The relative proteins expression was detected by western blot. Cell migration and invasion were evaluated using transwell assay. Moreover, dual-luciferase reporter and RNA immunoprecipitation assays were conducted to determine the relationship between miR-455-5p and circ_0007142 or SGK1. Finally, xenograft tumor model was established to confirm the effect of circ_0007142 on CRC progression in vivo. Circ_0007142 and SGK1 levels were clearly increased, while miR-455-5p level was reduced in CRC tissues and cell lines. Circ_0007142 silencing promoted cell apoptosis and inhibited cell proliferation, migration and invasion, while these effects of circ_0007142 were partially abolished by miR-455-5p inhibitor in CRC cells. Circ_0007142 could sponge miR-455-5p to regulate SGK1 expression. Moreover, the effects of miR-455-5p on cell proliferation, apoptosis, migration and invasion could be partially reversed by SGK1 overexpression. Besides, circ_0007142 knockdown also suppressed the progression of CRC in vivo. Collectively, Circ_0007142/miR-455-5p/SGK1 axis regulated cell proliferation, apoptosis, migration and invasion of CRC cells, providing a probable therapy target for CRC.

Wen T ，Wu H ，Zhang L ，Li K ，Xiao X ，Zhang L ，Zhang Y ... -  《-》

The circular RNA circ-ERBIN promotes growth and metastasis of colorectal cancer by miR-125a-5p and miR-138-5p/4EBP-1 mediated cap-independent HIF-1α translation.

Chen LY ，Wang L ，Ren YX ，Pang Z ，Liu Y ，Sun XD ，Tu J ，Zhi Z ，Qin Y ，Sun LN ，Li JM ... -  《Molecular Cancer》

Circ-E2F3 acts as a ceRNA for miR-204-5p to promote proliferation, metastasis and apoptosis inhibition in retinoblastoma by regulating ROCK1 expression.

Circular RNA (circRNA) plays an important role in the malignant progression of many tumors, including retinoblastoma (RB). However, the role and regulatory mechanism of circ-E2F3 in RB have not been fully elucidated. Quantitative real-time PCR was used to measure circ-E2F3, miR-204-5p and Rho-associated protein kinase 1 (ROCK1) expression. Cell proliferation, apoptosis and metastasis were monitored by MTT, colony formation, flow cytometry, transwell and wound healing assays. Dual-luciferase reporter assay was employed to verify the relationship between miR-204-5p and circ-E2F3 or ROCK1. ROCK1 protein expression was detected by western blot assay. Mice xenograft models were built to assess the role of circ-E2F3 on RB tumor growth. Circ-E2F3 was upregulated in RB tissues and cells. Silencing of circ-E2F3 inhibited the proliferation, migration, invasion, and induced the apoptosis of RB cells in vitro, as well as reduced RB tumor growth in vivo. MiR-204-5p could be sponged by circ-E2F3, and its inhibitor reversed the suppressive effect of circ-E2F3 silencing on RB progression. In addition, ROCK1 was confirmed to interact with miR-204-5p. MiR-204-5p regulated RB progression by targeting ROCK1. Also, circ-E2F3 positively regulated ROCK1 expression by sponging miR-204-5p. Circ-E2F3 functioned as a tumor promoter in RB through the miR-204-5p/ROCK1 axis.

Huang Y ，Xue B ，Pan J ，Shen N ... -  《-》

Circular RNA circ_0058123 Targets the miR-939-5p/RAC1 Pathway to Promote the Development of Colorectal Cancer.

Circular RNA (circRNA) can be used as a potential target for cancer treatment. However, the biological function and potential molecular mechanism of circ_0058123 in the development of colorectal cancer (CRC) are still unclear. The expression levels of circ_0058123, microRNA-939-5p (miR-939-5p) and Rac family small GTPase 1 (RAC1) were measured by quantitative real-time polymerase chain reaction or western blot assay. 5-Ethynyl-2'-deoxyuridine (EdU) incorporation assay, transwell assay, tube formation assay and flow cytometry apoptosis assay were conducted to assess CRC cell functions. In addition, protein expression was measured with western blot assay. Dual-luciferase reporter assays and RNA immunoprecipitation assay were conducted to confirm the relationships between miR-939-5p and circ_0058123, and miR-939-5p and RAC1. In vivo CRC tumor growth experiment also were carried out to determine circ_0058123-mediatede effects on tumor formation. Our data showed that circ_0058123 and RAC1 expression were increased, but miR-939-5p was decreased in both of CRC tissues and cell lines. Circ_0058123 depletion repressed CRC cell proliferation, migration, invasion and tube formation but promoted cell apoptosis. Down-regulation of circ_0058123 could significantly suppress the CRC progression, while the addition of miR-939-5p inhibitor could reverse this effect. Circ_0058123 directly targeted miR-939-5p, and RAC1 was a target of miR-939-5p. Furthermore, RAC1 overexpression could rescue the effect of miR-939-5p on CRC development. Lastly, silence of circ_0058123 inhibited CRC tumor growth in vivo. In conclusion, circ_0058123 could promote CRC progression through regulating the miR-939-5p/RAC1 axis and may be a valuable biomarker for early diagnosis and prognosis of CRC.

Gao J ，Chen J ，Huang X ，Zheng Y ，Hu K ... -  《-》

Circ_0000395 promotes cell growth, metastasis and oxaliplatin resistance by regulating miR-153-5p/MYO6 in colorectal cancer.

Circular RNAs (circRNAs) are involved in the regulation of colorectal cancer (CRC) progression and chemoresistence. Here, we attempted to reveal the function and mechanism of circ_0000395 in CRC chemoresistence. The expression levels of circ_0000395, microRNA (miR)-153-5p, and myosin VI (MYO6) were determined by quantitative real-time PCR. Cell growth, metastasis and oxaliplatin resistance were evaluated via EdU assay, colony formation assay, flow cytometry, transwell assay, and cell counting kit 8 assay. Xenograft tumor model was adopted to evaluate the role of circ_0000395 on CRC tumor growth and oxaliplatin sensitivity. Protein expression of drug-resistance markers and MYO6 was analyzed by western blot. The target relationship between miR-153-5p and circ_0000395 or MYO6 was validated via dual-luciferase reporter assay and RIP assay. Circ_0000395 expression was enhanced in CRC tissues and cells. Silencing of circ_0000395 repressed CRC cell proliferation, migration and invasion, while promoted apoptosis and oxaliplatin sensitivity. Besides, circ_0000395 knockdown also reduced CRC tumor growth and enhanced the sensitivity of tumor to oxaliplatin. Additionally, circ_0000395 acted as a sponge for miR-153-5p, and miR-153-5p targeted MYO6. Functional experiments suggested that miR-153-5p inhibitor or MYO6 overexpression could reverse the suppressive effect of circ_0000395 knockdown on CRC cell growth, metastasis and oxaliplatin resistance. Circ_0000395 promoted CRC cell growth, metastasis and oxaliplatin resistance via the miR-153-5p/MYO6 axis, which might provide new insights into the treatment of CRC.

Xiao L ，Zhu Y ，Xu H ，Lin L ，Li M ，Zhou Y ... -  《-》