Expression of Micro-RNA-492 (MiR-492) in Human Cervical Cancer Cell Lines is Upregulated by Transfection with Wild-Type P53, Irradiation, and 5-Fluorouracil Treatment In Vitro

Med Sci Monit. 2018 Oct 30:24:7750-7758. doi: 10.12659/MSM.911585.

Abstract

BACKGROUND The status of p53 is critical to the chemoradiosensitivity of cervical cancer cells. Wild-type p53 is essential to orchestrate the cellular response to cytotoxic stimuli. Our previous data illustrated that cervical cancer patients whose specimens overexpressed microR-492 (miR-492) were highly sensitive to concurrent chemoradiation. Although p53 activation has been reported to upregulate miR-492 by a miRNA profiling assay in lung cancer cells, the transcriptional regulation of miR-492 in cervical cancer cells remains poorly understood. Therefore, we aimed to decipher the relationship between p53 and miR-492 in cervical cancer cells. MATERIAL AND METHODS The expression of p53 and miR-492 in cervical cancer cell lines was measured by western blot and real-time PCR. After cells were transfected with wild-type p53 plasmid or were treated by irradiation and 5-fluorouracil (5-FU), the expression changes of p53 as well as miR-492 were examined by western blot and real-time PCR. The putative p53 binding site of miR-492 was first analyzed by bioinformatics tools, then validated by chromatin immunoprecipitation and dual-luciferase reporter assays. RESULTS We found that miR-492 was upregulated in cells with wild-type p53 compared to cells with mutant p53. Transfection of wild-type p53 plasmid or treatments with cytotoxic reagents including irradiation and 5-FU all induced miR-492 overexpression. Bioinformatics analysis and experimental validations further proved p53 interacted with miR-492 promoter directly. CONCLUSIONS In cervical cancer cells, p53 activated miR-492 expression transcriptionally.

MeSH terms

  • Cell Line, Tumor
  • Drug Resistance, Neoplasm
  • Female
  • Fluorouracil / therapeutic use
  • Gene Expression Regulation, Neoplastic
  • Humans
  • MicroRNAs / genetics*
  • MicroRNAs / metabolism
  • Radiotherapy
  • Transcriptional Activation
  • Transfection
  • Tumor Suppressor Protein p53 / genetics
  • Tumor Suppressor Protein p53 / metabolism*
  • Up-Regulation
  • Uterine Cervical Neoplasms / genetics*
  • Uterine Cervical Neoplasms / metabolism
  • Uterine Cervical Neoplasms / therapy*

Substances

  • MIRN492 microRNA, human
  • MicroRNAs
  • TP53 protein, human
  • Tumor Suppressor Protein p53
  • Fluorouracil