MicroRNA-6744-5p promotes anoikis in breast cancer and directly targets NAT1 enzyme

Objective: Anoikis is apoptosis that is induced when cells detach from the extracellular matrix and neighboring cells. As anoikis servesas a regulatory barrier, cancer cells often acquire resistance towards anoikis during tumorigenesis to become metastatic. MicroRNAs(miRNAs) are short strand RNA molecules that regulate genes post-transcriptionally by binding to mRNAs and reducing theexpression of its target genes. This study aimed to elucidate the role of a novel miRNA, miR-6744-5p, in regulating anoikis in breastcancer and identify its target gene. Methods: An anoikis resistant variant of the luminal A type breast cancer MCF-7 cell line (MCF-7-AR) was generated by selectingand amplifying surviving cells after repeated exposure to growth in suspension. MiRNA microarray analysis identified a list ofdysregulated miRNAs from which miR-6744-5p was chosen for overexpression and knockdown studies in MCF-7. Additionally,the miRNA was also overexpressed in a triple-negative breast cancer cell line, MDA-MB-231, to evaluate its ability to impair themetastatic potential of breast cancer cells. Results: This study showed that overexpression and knockdown of miR-6744-5p in MCF-7 increased and decreased anoikissensitivity, respectively. Similarly, overexpression of miR-6744-5p in MDA-MB-231 increased anoikis and also decreased tumor cellinvasion in vitro and in vivo. Furthermore, NAT1 enzyme was identified and validated as the direct target of miR-6744-5p. Conclusions: This study has proven the ability of miR-6744-5p to increase anoikis sensitivity in both luminal A and triple negativebreast cancer cell lines, highlighting its therapeutic potential in treating breast cancer. Cite this article as: Malagobadan S, Ho CS, Nagoor NH. MicroRNA-6744-5ppromotes anoikis in breast cancer and directly targets NAT1 enzyme. CancerBiol Med. 2020; 17: 101-111. doi: 10.20892/j.issn.2095-3941.2019.0010