MicroRNA 196B Regulates HOXA5, HOXB6 and GLTP Expression Levels in Colorectal Cancer Cells.

MiRNAs are non-coding RNAs that play important roles in the pathogenesis of human diseases by regulating target gene expression in specific cells or tissues. Previously we identified colorectal cancer (CRC) associated MIR196B, which was specifically up-regulated in CRC cells and tissue. We also identified 18 putative MIR196B target genes by comparing the mRNAs down-regulated in MIR196B-overexpressed cells with MIR196B target genes predicted by public bioinformatics tools. In this study, we verified the association between MIR196B and three genes, HOXA5, HOXB6 and GLTP. HOXA5, HOXB6 and GLTP transcripts were directly down-regulated by MIR196B. The mRNA and proteins levels of HOXA5, HOXB6 and GLTP were also down-regulated in CRC cells by the up-regulated MIR196B. GLTP protein expression was decreased in CRC tissues compared to adjacent non-tumor tissues. These results suggest that HOXA5, HOXB6, and GLTP were direct target genes of MIR196B in CRC cells, and that the up-regulated MIR196B in CRC tissue regulates the expression levels of HOXA5, HOXB6, and GLTP during colorectal carcinogenesis.