TCF21 hypermethylation regulates renal tumor cell clonogenic proliferation and migration

Saskia L. Gooskens, Timothy D. Klasson, Hendrik Gremmels, Ive Logister, Robert Pieters, Elizabeth J. Perlman, Rachel H. Giles*, Mary M. van den Heuvel-Eibrink

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

We recently identified hypermethylation at the gene promoter of transcription factor 21 (TCF21) in clear cell sarcoma of the kidney (CCSK), a rare pediatric renal tumor. TCF21 is a transcription factor involved in tubular epithelial development of the kidney and is a candidate tumor suppressor. As there are no in vitro models of CCSK, we employed a well-established clear cell renal cell carcinoma (ccRCC) cell line, 786-O, which also manifests high methylation at the TCF21 promoter, with consequent low TCF21 expression. The tumor suppressor function of TCF21 has not been functionally addressed in ccRCC cells; we aimed to explore the functional potential of TCF21 expression in ccRCC cells in vitro. 786-O clones stably transfected with either pBABE-TCF21-HA construct or pBABE vector alone were functionally analyzed. We found that ectopic expression of TCF21 in 786-O cells results in a trend toward decreased cell proliferation (not significant) and significantly decreased migration compared with mock-transfected 786-O cells. Although the number of colonies established in colony formation assays was not different between 786-O clones, colony size was significantly reduced in 786-O cells expressing TCF21. To investigate whether the changes in migration were due to epithelial-to-mesenchymal transition changes, we interrogated the expression of selected epithelial and mesenchymal markers. Although we observed upregulation of mRNA and protein levels of epithelial marker E-cadherin in clones overexpressing TCF21, this did not result in surface expression of E-cadherin as measured by fluorescence-activated cell sorting and immunofluorescence. Furthermore, mRNA expression of the mesenchymal markers vimentin (VIM) and SNAI1 was not significantly decreased in TCF21-expressing 786-O cells, while protein levels of VIM were markedly decreased. We conclude that re-expression of TCF21 in renal cancer cells that have silenced their endogenous TCF21 locus through hypermethylation results in reduced clonogenic proliferation, reduced migration, and reduced mesenchymal-like characteristics, suggesting a tumor suppressor function for transcription factor 21.

Original languageEnglish (US)
Pages (from-to)166-179
Number of pages14
JournalMolecular oncology
Volume12
Issue number2
DOIs
StatePublished - Feb 1 2018

Keywords

  • TCF21
  • clear cell sarcoma of the kidney
  • epithelial-to-mesenchymal transition
  • methylation
  • renal cell carcinoma
  • tumor suppressor

ASJC Scopus subject areas

  • Molecular Medicine
  • Genetics
  • Oncology
  • Cancer Research

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