Suppression of miR-22, a tumor suppressor in cervical cancer, by human papillomavirus 16 E6 via a p53/miR-22/HDAC6 pathway

PLoS One. 2018 Oct 31;13(10):e0206644. doi: 10.1371/journal.pone.0206644. eCollection 2018.

Abstract

MicroRNAs (miRNAs) are small non-coding RNAs that function to down-regulate gene expression involving in various cellular processes related to carcinogenesis. Recently, miR-22 was identified as a tumor-suppressing miRNA in many human cancers. However, the regulatory mechanism and the specific function of this miRNA in cervical cancer remain unclear. In the present study, we carried out gene transfection, western blot and quantitative RT-PCR to explore the regulatory mechanism and the functional role of miR-22 in cervical cancer. We verified that miR-22 was down-regulated in cervical cancer tissues and cervical cancer cell lines relative to matched non-tumor tissues and normal human cervical keratinocyte line (HCK1T). By contrast, histone deacetylase 6 (HDAC6) was inversely correlated with miR-22 in both cervical tissues and cancer cell lines. Mechanically, HDAC6 was down-regulated by miR-22 at the post-transcriptional level, via a specific target site within the 3'UTR, identified by a luciferase reporter assay. Moreover, we also showed that the correlation between miR-22 and HDAC6 expression was regulated by an E6/p53 pathway in HCK1Ts expressing HPV16 E6. For functional study, an ectopic expression of miR-22 could inhibit cell proliferation and migration, and could induce apoptosis of cervical cancer cell lines. These findings demonstrated that miR-22 was down-regulated in cervical cancer and inversely collated with its downstream target HDAC6. MiR-22 acts as tumor suppressor by inhibiting proliferation and migration, and by inducing apoptosis of cervical cancer cell lines by targeting the 3'UTR of HDAC6. This newly identified E6/p53/miR-22/HDAC6 regulatory network might be a candidate therapeutic target for cervical cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line, Tumor
  • Cell Movement / physiology
  • Cell Proliferation / physiology
  • Female
  • Gene Expression Regulation, Neoplastic*
  • Histone Deacetylase 6 / genetics
  • Histone Deacetylase 6 / metabolism*
  • Humans
  • Keratinocytes / metabolism
  • MicroRNAs / genetics
  • MicroRNAs / metabolism*
  • Oncogene Proteins, Viral / genetics
  • Oncogene Proteins, Viral / metabolism*
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism*
  • Signal Transduction / physiology
  • Tumor Suppressor Protein p53 / genetics
  • Tumor Suppressor Protein p53 / metabolism*
  • Uterine Cervical Neoplasms / metabolism*
  • Uterine Cervical Neoplasms / virology

Substances

  • E6 protein, Human papillomavirus type 16
  • MIRN22 microRNA, human
  • MicroRNAs
  • Oncogene Proteins, Viral
  • Repressor Proteins
  • Tumor Suppressor Protein p53
  • HDAC6 protein, human
  • Histone Deacetylase 6

Grant support

This work was supported by the Thailand Research Fund and Khon Kaen University through the Royal Golden Jubilee Ph.D. Program (grant no. PHD/0296/2552), Faculty of Medicine, Khon Kaen University (grant no. IN59127) and Khon Kaen University, Thailand (grant no. 61004604), and had received scholarship under the Post-Doctoral Training Program from Research Affairs and Graduate School, Khon Kaen University, Thailand (grant no. 58443). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.