574442

MIR489

To investigate the role of microRNAs in the development of chemoresistance and related epithelial-mesenchymal transition (EMT), we examined the effect of miR-489 in adriamycin (ADM)-resistant human breast cancer cells (MCF-7/ADM). MiR-489 was significantly suppressed in MCF-7/ADM cells compared with chemosensitive parental control MCF-7/WT cells. Forced-expression of miR-489 reversed chemoresistance. Furthermore, Smad3 was identified as the target of miR-489 and is highly expressed in MCF-7/ADM cells. Forced expression of miR-489 both inhibited Smad3 expression and Smad3 related EMT properties. Finally, the interactions between Smad3, miR-489 and EMT were confirmed in chemoresistant tumor xenografts and clinical samples, indicating their potential implication for treatment of chemoresistance.CI - Copyright (c) 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

microRNA-489 (miR-489) is a novel cancer-related miRNAs and functions as a tumor suppressor in human cancers. While, the clinical significance of miR-489 and its role in colorectal cancer (CRC) remain rarely known. Here, we found that the levels of miR-489 in CRC tissues were significantly lower than those in matched tumor-adjacent tissues. Furthermore, decreased levels of miR-489 also observed in CRC cell lines compared to HIEC cells. Clinicopathological analysis revealed that miR-489 underexpression was positively correlated with advanced pT stage, pN stage and AJCC stage. Moreover, miR-489 low expressing CRC patients showed a obvious shorter survival. Functionally, miR-489 restoration inhibited cell migration and invasion as well as epithelial-mesenchymal transition (EMT) in HCT116 cells, while miR-489 loss facilitated these cellular processes in SW480 cells. In vivo experiments revealed that miR-489 overexpression reduced the number of metastatic nodules in nude mice liver. Notably, TWIST1 was recognized as a direct downstream target of miR-489 in CRC cells. Interestingly, TWIST1 restoration abrogated the effects of miR-489 on CRC cells with enhanced cell migration, invasion and EMT process. Furthermore, overexpression of long noncoding RNA cardiac hypertrophy-related factor (lncRNA CHRF) was inversely correlated with miR-489 expression in CRC tissues. CHRF knockdown increased the expression of miR-489 and suppressed EMT events of HCT116 cells, while CHRF overexpression showed opposite effects on miR-489 expression and EMT in SW480 cells. Taken together, this work support the first evidence that lncRNA CHRF-induced miR-489 loss facilitates metastasis and EMT process of CRC cells probably via TWIST1/EMT signaling pathway.