Druesne Nathalie, Pagniez Anthony, Mayeur Camille, Thomas Muriel, Cherbuy Claire, Duée Pierre-Henri, Martel Paule, Chaumontet Catherine
Laboratoire de Nutrition et Securite Alimentaire, INRA, Jouy-en-Josas, France.
Carcinogenesis. 2004 Jul;25(7):1227-36. doi: 10.1093/carcin/bgh123. Epub 2004 Feb 19.
Diallyl disulfide (DADS) is a naturally occurring organosulfur compound, from garlic, which exerts pleiotropic biological effects. In rodents, DADS inhibits colon chemically induced carcinogenesis. DADS anti-promoting effect may partly result from its ability to inhibit tumoral cell proliferation in vivo and in vitro. As far as DADS may modulate the expression of a subset of genes, we investigated DADS effect on histone acetylation, in two human colon tumor cell lines. Our study demonstrates that in Caco-2 and HT-29 cells treated for 6 h, 200 microM DADS increases histone H3 acetylation (x2 and x1.4, respectively). In Caco-2 cells, we also observed histone H4 hyperacetylation, preferentially at the lysine residues 12 and 16. We explored the effects of DADS and one of its metabolites, allyl mercaptan (AM), on histone deacetylase (HDAC) activity: using nuclear extracts of Caco-2 cells, 200 microM DADS decreased HDAC activity by 29% and AM at the same concentration was more efficient (92% inhibition). We also observed that DADS induced an increase in p21(waf1/cip1) expression, at mRNA and protein levels, in both cell lines. This effect was associated with an accumulation of cells in the G2 phase of the cell cycle. Our results suggest that in Caco-2 and HT-29 cells, DADS could inhibit cell proliferation through the inhibition of HDAC activity, histone hyperacetylation and increase in p21(waf1/cip1) expression. The present study provides evidence for cellular and molecular responses triggered by DADS that could be linked to its effect on histone acetylation and play a role in its protective properties on colon carcinogenesis.
二烯丙基二硫化物（DADS）是一种天然存在的有机硫化合物，来自大蒜，具有多种生物学效应。在啮齿动物中，DADS可抑制化学诱导的结肠癌发生。DADS的抗促进作用可能部分源于其在体内和体外抑制肿瘤细胞增殖的能力。鉴于DADS可能调节一部分基因的表达，我们研究了DADS对两种人结肠肿瘤细胞系中组蛋白乙酰化的影响。我们的研究表明，在经6小时处理的Caco-2和HT-29细胞中，200微摩尔/升的DADS可使组蛋白H3乙酰化增加（分别增加2倍和1.4倍）。在Caco-2细胞中，我们还观察到组蛋白H4的高度乙酰化，主要发生在赖氨酸残基12和16处。我们探究了DADS及其一种代谢产物烯丙基硫醇（AM）对组蛋白脱乙酰酶（HDAC）活性的影响：使用Caco-2细胞的核提取物，200微摩尔/升的DADS可使HDAC活性降低29%，相同浓度的AM效果更显著（抑制率达92%）。我们还观察到，在两种细胞系中，DADS在mRNA和蛋白质水平上均诱导p21（waf1/cip1）表达增加。这种效应与细胞周期G2期的细胞积累有关。我们的结果表明，在Caco-2和HT-29细胞中，DADS可能通过抑制HDAC活性、组蛋白高度乙酰化以及增加p21（waf1/cip1）表达来抑制细胞增殖。本研究为DADS引发的细胞和分子反应提供了证据，这些反应可能与其对组蛋白乙酰化的影响有关，并在其对结肠癌发生的保护作用中发挥作用。
