MiR-490-5p Functions as an OncomiR in Breast Cancer by Targeting NFATc4

Abstract

Breast cancer is a serious health problem worldwide in women. MicroRNAs are small non-coding RNAs of 18–25 nucleotides in length that post-transcriptionally modulate gene expression. <em>MiR-490</em> has been reported as a tumor suppressor and oncomiR microRNA in breast cancer with two separate targets, NFAT and Rho. NFAT is one of the targets for miR-490 but the relationship between <em>hsa</em>-<em>miR-490</em> and <em>NFATc3</em>, <em>NFATc4</em> are not clear yet. Except for NFAT5, the other members of NFAT are activated by Ca²⁺ influx in the cell, either via the PLC-γ pathway or via store-operated Ca²⁺ entry, typically in T lymphoid cells. In a cross-sectional comparative study, peripheral blood samples were collected from 30 subjects with breast cancer and 30 healthy individuals as a control group. Gene expression analysis of peripheral blood mononuclear cells (PBMCs) was performed using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) to study the <em>NFATc3, NFATc4, </em>and <em>hsa-miR-490-5p</em> gene expression alterations. As per the obtained results, a significant decrease was observed in the expression level of <em>NFATc4 (P<0.05)</em>, while <em>hsa-miR-490-5p</em> expression found to be elevated in PBMCs of breast cancer patient <em>(P<0.05)</em>. Expression changes were not significant for <em>NFATc3 </em>gene <em>(P>0.05)</em>. Taken together findings of this study indicated that serum <em>hsa-miR-490-5p</em> acts as an oncomiR by direct targeting the <em>NFATc4.</em>