MicroRNA-9 promotes the proliferation, migration, and invasion of breast cancer cells via down-regulating FOXO1

• D.-Z. Liu ^[1] ; B. Chang ^[1] ; X.-D. Li ^[1] ; Q.-H. Zhang ^[1] ; Y.-H. Zou ^[1]
  1. [1] Shantou University Medical College

     Shantou University Medical College

     China

     
• Localización: Clinical & translational oncology, ISSN 1699-048X, Vol. 19, Nº. 9 (September 2017), 2017, págs. 1133-1140
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • Purpose The objective of the study was to investigate the role of microRNA-9 (miR-9) targeting forkhead box O1 (FOXO1) in the proliferation, migration, and invasion of breast cancer cells.

    Methods Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to determine the expressions of miR-9 and FOXO1 mRNA in breast cancer tissues, normal breast tissues, breast cancer cell lines, and normal breast epithelial cells. After the up-regulation of miR-9 expression, qRT-PCR and Western blotting were used to determine the expression of FOXO1. The luciferase reporter gene assay was used to validate the target gene. The CCK-8 assay, scratch-wound healing assay, and Transwell invasion assay were used to investigate the changes in the proliferation, migration, and invasion of breast cancer cells, respectively.

    Results MicroRNA-9 expression was significantly up-regulated in breast cancer tissues and breast cancer cell lines when compared with normal breast tissues and normal breast epithelial cells (both P < 0.05). FOXO1 mRNA and protein expressions were substantially down-regulated in breast cancer tissues and breast cancer cell lines when compared with normal breast tissues and normal breast epithelial cells (both P < 0.05). There can be a negative correlation between miR-9 and FOXO1 mRNA in breast cancer. Luciferase reporter gene assay indicated that miR-9 can down-regulate FOXO1 expression at a post-transcriptional level through binding specifically to FOXO1 3′UTR. The results of CCK-8 assay, scratch-wound healing assay, and Transwell invasion assay revealed that the inhibition of miR-9 can suppress MCF7 cell proliferation, migration, and invasion. Additionally, the expression of miR-9 increased significantly whilst that of FOXO1 decreased substantially as the disease progressed (P < 0.05).

    Conclusions Our study provides evidence that miR-9 can promote the proliferation, migration, and invasion of breast cancer cells via down-regulating FOXO1.