SET overexpression decreases cell detoxification efficiency: ALDH2 and GSTP1 are downregulated, DDR is impaired and DNA damage accumulates

FEBS J. 2012 Dec;279(24):4615-28. doi: 10.1111/febs.12047. Epub 2012 Nov 23.

Abstract

Alcohol and tobacco consumption are risk factors for head and neck squamous cell carcinoma (HNSCC). Aldehyde dehydrogenase 2 (ALDH2) and glutathione S-transferase pi 1 (GSTP1) are important enzymes for cellular detoxification and low efficiencies are implicated in cancer. We assessed the potential role of SET protein overexpression, a histone acetylation modulator accumulated in HNSCC, in gene regulation and protein activity of ALDH2 and GSTP1. SET was knocked down in HN13, HN12 and Cal27, and overexpressed in HEK293 cells; ethanol and cisplatin were the chemical agents. Cells with SET overexpression (HEK293/SET, HN13 and HN12) showed lower ALDH2 and GSTP1 mRNA levels and trichostatin A increased them (real-time PCR). Ethanol upregulated GSTP1 and ALDH2 mRNAs, whereas cisplatin upregulated GSTP1 in HEK293 cells. SET-chromatin binding revealed SET interaction with ALDH2 and GSTP1 promoters, specifically via SET NAP domain; ethanol and cisplatin abolished SET binding. ALDH2 and GSTP1 efficiency was assessed by enzymatic and comet assay. A lower ALDH2 activity was associated with greater DNA damage (tail intensity) in HEK293/SET compared with HEK293 cells, whereas HN13/siSET showed ALDH2 activity higher than HN13 cells. HN13/siSET cells showed increased tail intensity. Cisplatin-induced DNA damage response showed negative relationship between SET overexpression and BRCA2 recruitment. SET downregulated repair genes ATM, BRCA1 and CHEK2 and upregulated TP53. Cisplatin-induced cell-cycle arrest occurred in G(0) /G(1) and S in HEK293 cells, whereas HEK293/SET showed G(2) /M stalling. Overall, cisplatin was more cytotoxic for HN13 than HN13/siSET cells. Our data suggest a role for SET in cellular detoxification, DNA damage response and genome integrity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aldehyde Dehydrogenase / genetics*
  • Aldehyde Dehydrogenase, Mitochondrial
  • Cell Line
  • DNA Damage*
  • DNA-Binding Proteins
  • Down-Regulation
  • Glutathione S-Transferase pi / genetics*
  • Histone Chaperones / genetics*
  • Humans
  • Transcription Factors / genetics*

Substances

  • DNA-Binding Proteins
  • Histone Chaperones
  • SET protein, human
  • Transcription Factors
  • ALDH2 protein, human
  • Aldehyde Dehydrogenase
  • Aldehyde Dehydrogenase, Mitochondrial
  • Glutathione S-Transferase pi