Mitochondrial transcription factor A (TFAM) is required for mitochondrial DNA (mtDNA) replication and transcription. microRNAs (miRNAs) act as key factors in the regulation of gene expression. However, the roles of TFAM and certain miRNAs and their association in cancer development remain unclear. The present study reported that the expression of TFAM was significantly increased in bladder cancer, while the expression of miRNA-590-3p was downregulated. The luciferase assay showed that TFAM was the direct target of miRNA-590-3p. Furthermore, the forced overexpression of miRNA-590-3p significantly inhibited the proliferation, migration and colony-forming ability of 5637 cells, which was in contrast with the results from the forced overexpression of TFAM in the 5637 cells. Furthermore, cell proliferation- and migration-related genes, including phosphoinositide-3-kinase (PI3K), Akt, matrix metalloproteinase (MMP)-2 and MMP9, were significantly downregulated in the miRNA-590-3p-overex-pressing 5637 cells, but upregulated in the TFAM-overexpressing cells. In conclusion, the present study suggested that TFAM, a direct target of miRNA-590-3p, may play a significant role in the tumorigenesis of bladder cancer and thus may be a promising target for cancer therapeutics.
Keywords: bladder cancer; microRNA-590-3p; mitochondrial transcription factor A.