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

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. MiR-490 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 hsa-miR-490 and NFATc3, NFATc4 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 NFATc3, NFATc4, and hsa-miR-490-5p gene expression alterations.   As per the obtained results, a significant decrease was observed in the expression level of NFATc4 (P<0.05), while hsa-miR-490-5p expression found to be elevated in PBMCs of breast cancer patient (P<0.05).  Expression changes were not significant for NFATc3 gene (P>0.05). Taken together findings of this study indicated that serum hsa-miR-490-5p acts as an oncomiR by direct targeting the NFATc4.