Overexpression of miR-361-5p in triple-negative breast cancer (TNBC) inhibits migration and invasion by targeting RQCD1 and inhibiting the EGFR/PI3K/Akt pathway

Bosn J Basic Med Sci. 2019 Feb 12;19(1):52-59. doi: 10.17305/bjbms.2018.3399.


Triple-negative breast cancer (TNBC) is the leading cause of cancer-related death in women. Previous studies indicated that miR-361-5p was downregulated in breast cancer, however, the exact effect of miR-361-5p on TNBC requires further investigation. In the present study, we investigated whether miR-361-5p can act as a tumor suppressor by targeting required for cell differentiation 1 homolog (RQCD1) and inhibiting epidermal growth factor receptor (EGFR)/phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) pathway in TNBC. The expression of miR-361-5p and RQCD1 was determined by quantitative reverse transcription PCR (qRT-PCR) and/or western blot in TNBC and the adjacent tissues. miR-361-5p mimics were constructed and transfected to TNBC cell line MDA-MB-231. Cells were divided into three groups: blank control group, miRNA mimic negative control (NC) group, and miR-361-5p mimics group. Expression of miR-361-5p, mRNA and protein expression of PI3K, Akt, EGFR, phosphorylated (p)-EGFR/PI3K/Akt, and protein expression of RQCD1 and matrix metallopeptidase 9 (MMP-9) in MDA-MB-231 were measured by qRT-PCR/western blot after transfection. Cell viability was determined by CCK-8 assay. Cell migration and invasion ability were evaluated by scratch and transwell assay, respectively. miR-361-5p target gene was determined by bioinformatics analysis and luciferase reporter assay. RQCD1 was identified as a target of miR-361-5p by TargetScan and confirmed by luciferase reporter assay. Downregulated miR-361-5p and upregulated RQCD1 were observed in TNBC tissues. Expression of EGFR, PI3K, Akt and MMP-9 was inhibited in cells treated with miR-361-5p mimics. Transfection of miR-361-5p mimics also inhibited the phosphorylation of EGFR, PI3K, and Akt. Suppressed cell viability, migration, and invasion was found in miR-361-5p mimics groups. Our results indicated that overexpression of miR-361-5p might act as a suppressor in TNBC by targeting RQCD1 to inhibit the EGFR/PI3K/Akt signaling pathway.

MeSH terms

  • Adult
  • Breast Neoplasms / metabolism*
  • Breast Neoplasms / pathology*
  • Cell Line, Tumor
  • Cell Movement / genetics
  • ErbB Receptors / biosynthesis
  • ErbB Receptors / genetics
  • Female
  • Humans
  • MicroRNAs / biosynthesis*
  • Neoplasm Invasiveness / genetics
  • Neoplasm Invasiveness / pathology
  • Oncogene Protein v-akt / biosynthesis
  • Oncogene Protein v-akt / genetics
  • Phosphatidylinositol 3-Kinases / biosynthesis
  • Phosphatidylinositol 3-Kinases / genetics
  • Phosphorylation / genetics
  • Signal Transduction / genetics*
  • Transcription Factors / biosynthesis*
  • Transcription Factors / genetics
  • Triple Negative Breast Neoplasms / metabolism*
  • Triple Negative Breast Neoplasms / pathology*


  • CNOT9 protein, human
  • MIRN361 microRNA, human
  • MicroRNAs
  • Transcription Factors
  • Phosphatidylinositol 3-Kinases
  • EGFR protein, human
  • ErbB Receptors
  • Oncogene Protein v-akt