MicroRNA-4284 inhibits colon cancer epithelial-mesenchymal transition by down-regulating Perilipin 5

Background: MicroRNA (miR) has been suggested in the development of several types of cancer; yet, the exact function of miR-4284 in colon cancer remains elusive. Methods: MiR-4284 expression was assessed in normal colon cell line CCD-18Co, and HT-29 and SW480 cell lines representing human colon cancer. Potential target gene of miR-4284 was predicted using TargetScanHuman, and experimentally verified using luciferase report assay. Wound-healing, cell invasion and attachment were evaluated to determine the effect of miR-4284 on the migration, invasion, and metastatic properties of colon cancer cell lines. Expression of epithelial-mesenchymal transition (EMT) phenotypic protein hallmarks, including N-cadherin, E-cadherin, as well as Vimentin, was also evaluated. Results: MiR-4284 was significantly decreased in colon cancer cell lines, and Perilipin 5 (PLIN5) was found to be directly targeted by miR-4284. Ectopic expression of miR-4284 significantly reduced endogenous expression level of PLIN5 in colon cancer cell lines, suppressing migration, invasion, and metastatic phenotypes. In addition, re-introducing miR-4284 reversed the expression profile of EMT markers. Conclusion: Our findings for the first time identify miR-4284 as an anti-tumor miRNA in colon cancer, which acts to reduce PLIN5 and inhibit EMT, leading to inhibited colon cancer tumorigenesis. These results highlight the potential of miR-4284 as a therapeutic target in metastatic colon cancer.