MicroRNA-141 regulates the tumour suppressor DLC1 in colorectal cancer
Abstract:
Our previous study has showed that DLC1 acts as a functional tumor suppressor in colorectal cancer (CRC) cell lines. The aims of this study were to determine whether DLC1 is a target of MicroRNA (miRNA) regulation and to evaluate the role of this mechanism in CRC. By bioinformatics approach and literature, miR-141 was chosen for further study. The miR-141 mimic, miR-141 inhibitor were synthesized and transfected to Lovo cells. Cell growth was determined by MTT and in vivo models. The flow cytometric analysis for cell cycle determination and transwell assays for evaluating the cell invasion were used. Luciferase reporter assays and Western blots showed that DLC1 was a direct target of miR-141 in CRC. The expression levels of miR-141 were obviously up-regulated in CRC tissues compared to non-cancerous tissues, while DLC1 expression levels were down-regulated in a high proportion of clinical samples (14/18). In addition, correlation analyses revealed negative correlation between miR-141 levels and DLC1 expression levels in CRC tissues. MiR-141 overexpression promoted cell growth in vitro and in vivo, promoted cell cycle progression and invasion in Lovo cells. Furthermore, re-introduction of DLC-1 in miR-141-overexpressing Lovo cells decreased growth rate of cells, increase of the percentage in G0/G1 phase and decreased the number of migrating cells. In conclusion, we demonstrated that miR-141 is up-regulated in CRC and acts as a functional oncogene by targeting DLC1.