574456

MIR497

microRNA 497;MIR497;microRNA 497

-

17p13.1

ncRNA

Current genome-wide microRNA (miRNA) expression signature analysis using deep sequencing technologies can drive the discovery of novel cancer pathways regulated by oncogenic and/or tumor suppressive miRNAs. We determined the genome-wide miRNA expression signature in bladder cancer (BC) by deep sequencing technology. A total of ten small RNA libraries were sequenced (five BCs and five samples of histologically normal bladder epithelia (NBE)), and 13,190,619 to 18,559,060 clean small RNA reads were obtained. A total of 933 known miRNAs and 17 new miRNA candidates were detected in this analysis. Among the known miRNAs, a total of 60 miRNAs were significantly downregulated in BC compared with NBE. We also found that several miRNAs, such as miR-1/133a, miR-206/133b, let-7c/miR-99a, miR-143/145 and miR-195/497, were located close together at five distinct loci and constituted clustered miRNAs. Among these clustered miRNAs, we focused on the miR-195/497 cluster because this clustered miRNA had not been analyzed in BC. Transfection of mature miR-195 or miR-497 in two BC cell lines (BOY and T24) significantly inhibited cancer cell proliferation, migration and invasion, suggesting that the miR-195/497 cluster functioned as tumor suppressors in BC. Regarding the genes targeted by the miR-195/497 cluster, the TargetScan algorithm showed that 6,730 genes were putative miR-195/497 targets, and 113 significantly enriched signaling pathways were identified in this analysis. The "pathways in cancer" category was the most enriched, involving 104 candidate target genes. Gene expression data revealed that 27 of 104 candidate target genes were actually upregulated in BC clinical specimens. Luciferase reporter assays and Western blotting demonstrated that BIRC5 and WNT7A were directly targeted by miR-195/497. In conclusion, aberrant expression of clustered miRNAs was identified by deep sequencing, and downregulation of miR-195/497 contributed to BC progression and metastasis. tumor suppressive miRNA-mediated cancer pathways provide new insights into the potential mechanisms of BC oncogenesis.

The study aims to investigate the effect of microRNA-497 (miR-497) expression and bufalin treatment in regulating colorectal cancer invasion and metastasis. The expression of miR-497 in colorectal cancer cells with prior treatment with bufalin was determined using real-time quantitative PCR. The nude mouse abdominal aortic ring assay and the human umbilical vein endothelial cell (HUVEC) migration assays were used to measure the angiogenic effect of bufalin. The effect of both bufalin treatment and miR-497 overexpression on colorectal cancer metastasis was measured using an animal tumor model together with in vivo imaging. These results suggested: (1) In the HCT116 cells and HUVECs, proliferation was inhibited in a time-dependent and/or concentration-dependent manner following the administration of bufalin; (2) Bufalin inhibited cell migration in a concentration-dependent manner by cell motility assays; (3) In the aortic ring assay, administration bufalin to the aortic ring significantly promoted micro-angiogenesis of nude mouse abdominal aorta in a concentration-dependent and time-dependent manner; (4) miR-497 was upregulated in human colorectal cancer HCT116 cells treated with different concentrations of bufalin in a concentration-dependent manner; and (5) Combined application of bufalin and miR-497 significantly reduced metastatic lesions and reduced weight loss compared with bufalin alone and control groups in vivo. This study revealed that bufalin inhibited angiogenesis and regulated miR-497 expression and that bufalin and miR-497 acted in synergy to inhibit colorectal cancer metastasis, resulting in improved quality of life in a nude mouse model.