METTL14 promotes the migration and invasion of breast cancer cells by modulating N6‑methyladenosine and hsa‑miR‑146a‑5p expression.

Breast cancer (BC) is the most frequently diagnosed cancer and the leading cause of cancer‑related death among women worldwide. Evidence indicates that posttranscriptional N6‑methyladenosine (m6A) modification modulates BC development. In the present study, we assessed BC and normal tissues to investigate this connection. RNA m6A levels were determined by methylation quantification assay. The effects of methyltransferase‑like 14 (METTL14) gain‑of‑expression or co‑transfection with an m6A inhibitor on cell migration and invasion abilities were determined by Transwell assays. The levels of differentially expressed (DE) miRNAs were verified by real‑time quantitative PCR (RT‑qPCR). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes analyses (KEGG) were performed to analyze potential function of target genes of the DE miRNAs. The effects of candidate miRNAs modulated by METTL14 on cell migration and invasion abilities were confirmed by Transwell assays. We demonstrated that m6A methyltransferase METTL14 was significantly upregulated in BC tissues compared with normal tissues. METTL14 gain‑ and loss‑of‑expression regulated m6A levels in MCF‑7 and MDA‑MB‑231 cells. The cell function assays revealed that METTL14 overexpression enhanced the migration and invasion capacities of BC cells. Moreover, treatment with the m6A inhibitor suppressed this enhanced cell migration and invasion. Additionally, aberrant expression of METTL14 reshaped the miRNA profile in BC cell lines. The remodeled DE miRNA/mRNA network was found to be most enriched in cancer pathways, and DE miRNAs were enriched in cell adhesion terms. hsa‑miR‑146a‑5p modulated by METTL14 promoted cell migration and invasion. METTL14 modulates m6A modification and hsa‑miR‑146a‑5p expression, thereby affecting the migration and invasion of breast cancer cells.