Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, 14040-903 Ribeirão Preto, SP, Brazil.
FEBS J. 2012 Dec;279(24):4615-28. doi: 10.1111/febs.12047. Epub 2012 Nov 23.
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.
酒精和烟草的摄入是头颈部鳞状细胞癌（HNSCC）的危险因素。乙醛脱氢酶 2（ALDH2）和谷胱甘肽 S-转移酶 pi1（GSTP1）是细胞解毒的重要酶，其效率低下与癌症有关。我们评估了 SET 蛋白过表达在 HNSCC 中作为组蛋白乙酰化调节剂的潜在作用，及其对 ALDH2 和 GSTP1 的基因调控和蛋白活性的影响。SET 在 HN13、HN12 和 Cal27 中被敲低，在 HEK293 细胞中被过表达；乙醇和顺铂是化学试剂。过表达 SET 的细胞（HEK293/SET、HN13 和 HN12）显示出较低的 ALDH2 和 GSTP1 mRNA 水平，而曲古抑菌素 A 增加了它们的水平（实时 PCR）。乙醇上调 GSTP1 和 ALDH2 mRNA，而顺铂上调 HEK293 细胞中的 GSTP1。SET-染色质结合揭示了 SET 与 ALDH2 和 GSTP1 启动子的相互作用，特别是通过 SET NAP 结构域；乙醇和顺铂消除了 SET 结合。通过酶和彗星试验评估了 ALDH2 和 GSTP1 的效率。与 HEK293 细胞相比，HEK293/SET 中较低的 ALDH2 活性与更大的 DNA 损伤（尾部强度）相关，而 HN13/siSET 显示出高于 HN13 细胞的 ALDH2 活性。HN13/siSET 细胞显示出增加的尾部强度。顺铂诱导的 DNA 损伤反应显示 SET 过表达与 BRCA2 募集之间呈负相关。SET 下调修复基因 ATM、BRCA1 和 CHEK2，并上调 TP53。顺铂诱导的细胞周期阻滞发生在 HEK293 细胞的 G0/G1 和 S 期，而 HEK293/SET 显示 G2/M 期停滞。总的来说，顺铂对 HN13 的细胞毒性大于 HN13/siSET 细胞。我们的数据表明 SET 在细胞解毒、DNA 损伤反应和基因组完整性中起作用。
