ATF3 downmodulates its new targets IFI6 and IFI27 to suppress the growth and migration of tongue squamous cell carcinoma cells

PLoS Genet. 2021 Feb 4;17(2):e1009283. doi: 10.1371/journal.pgen.1009283. eCollection 2021 Feb.

Abstract

Activating transcription factor 3 (ATF3) is a key transcription factor involved in regulating cellular stress responses, with different expression levels and functions in different tissues. ATF3 has also been shown to play crucial roles in regulating tumor development and progression, however its potential role in oral squamous cell carcinomas has not been fully explored. In this study, we examined biopsies of tongue squamous cell carcinomas (TSCCs) and found that the nuclear expression level of ATF3 correlated negatively with the differentiation status of TSCCs, which was validated by analysis of the ATGC database. By using gain- or loss- of function analyses of ATF3 in four different TSCC cell lines, we demonstrated that ATF3 negatively regulates the growth and migration of human TSCC cells in vitro. RNA-seq analysis identified two new downstream targets of ATF3, interferon alpha inducible proteins 6 (IFI6) and 27 (IFI27), which were upregulated in ATF3-deleted cells and were downregulated in ATF3-overexpressing cells. Chromatin immunoprecipitation assays showed that ATF3 binds the promoter regions of the IFI6 and IFI27 genes. Both IFI6 and IFI27 were highly expressed in TSCC biopsies and knockdown of either IFI6 or IFI27 in TSCC cells blocked the cell growth and migration induced by the deletion of ATF3. Conversely, overexpression of either IFI6 or IFI27 counteracted the inhibition of TSCC cell growth and migration induced by the overexpression of ATF3. Finally, an in vivo study in mice confirmed those in vitro findings. Our study suggests that ATF3 plays an anti-tumor function in TSCCs through the negative regulation of its downstream targets, IFI6 and IFI27.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Activating Transcription Factor 3 / genetics
  • Activating Transcription Factor 3 / metabolism*
  • Animals
  • Carcinoma, Squamous Cell / genetics
  • Carcinoma, Squamous Cell / metabolism*
  • Cell Line, Tumor
  • Cell Movement / genetics
  • Cell Nucleus / metabolism
  • Cell Proliferation / genetics
  • Chromatin Immunoprecipitation
  • Disease Progression
  • Down-Regulation
  • Female
  • Gene Expression Regulation, Neoplastic / genetics
  • Gene Knockdown Techniques
  • Humans
  • Immunohistochemistry
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Mice
  • Mice, Nude
  • Mitochondrial Proteins / genetics
  • Mitochondrial Proteins / metabolism*
  • Neoplasm Grading
  • Promoter Regions, Genetic
  • RNA, Small Interfering
  • RNA-Seq
  • Tongue Neoplasms / genetics
  • Tongue Neoplasms / metabolism*
  • Tongue Neoplasms / pathology
  • Up-Regulation

Substances

  • ATF3 protein, human
  • Activating Transcription Factor 3
  • IFI27 protein, human
  • IFI6 protein, human
  • Membrane Proteins
  • Mitochondrial Proteins
  • RNA, Small Interfering

Grant support

This work was supported by The National Key Research and Development Program of China (2017YFA0104604) (http://www.most.gov.cn), the General Program of National Natural Science Foundation of China (81772093, 82073470) (https://isisn.nsfc.gov.cn), the Key Program of Shandong Province Natural Science Foundation (ZR2019ZD36) and The Key Research and Development Program of Shandong Province (2019GSF108107) (http://cloud.sdstc.gov.cn/). All funds were awarded to X.WU. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.