Genistein protects prostate cells against hydrogen peroxide-induced DNA damage and induces expression of genes involved in the defence against oxidative stress
Genistein protects prostate cells against hydrogen peroxide-induced DNA damage and induces expression of genes involved in the defence against oxidative stress
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DOI：
10.1093/carcin/bgl082
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发表时间：
2006-11-01
期刊：
影响因子：
4.7
通讯作者：
Pool-Zobel, Beatrice L.
中科院分区：
文献类型：
--
作者：
Raschke, Marian;Rowland, Ian R.;Pool-Zobel, Beatrice L.
前列腺癌是西方社会最常见的癌症类型之一，主要发生在老年男性中。与年龄相关的前列腺癌的增加与氧化DNA损伤的进行性积累有关，这可能是由衰老过程中细胞抗氧化防御的下降所支持的。在许多亚洲国家，大豆食品是饮食不可或缺的一部分，患前列腺癌的风险要低得多。因此，大豆异黄酮在前列腺细胞中具有化学预防活性。在这里，我们已经调查的假设，大豆异黄酮可以保护LAPC-4前列腺细胞的DNA氧化应激相关的损伤，通过增强抗氧化基因和蛋白质的表达。用染料木黄酮（1-30 μ M）预孵育24小时，可保护细胞免受过氧化氢诱导的DNA损伤，如彗星试验所示。两个cDNA宏阵列，每个包含96个基因的生物转化和应激反应的分析，揭示了3个基因在1 μ M和19个基因在10 μ M染料木素调制的表达。实时PCR证实了诱导的三个基因编码的产品具有抗氧化活性，即谷胱甘肽还原酶（2.7倍），微粒体谷胱甘肽S-转移酶1（1.9倍）和金属硫蛋白1X（6.3倍），在1-30 μ M染料木素。相比之下，17 β-雌二醇在0.3 μ M（2.0倍）时降低了金属硫蛋白1X的表达，这可能表明雌激素受体介导了该基因的调节。免疫细胞化学染色显示金属硫蛋白在30 μ M染料木素诱导，而它们的细胞内定位不受影响。以前发现金属硫蛋白可以保护细胞免受过氧化氢诱导的DNA损伤。因此，我们的研究结果表明，金雀异黄素保护前列腺细胞氧化应激相关的DNA损伤，大概是通过诱导抗氧化产物，如金属硫蛋白的表达。因此，染料木黄酮可能会抵消与年龄相关的重要抗氧化防御系统的下降，从而保持DNA的完整性。
Prostate cancer is one of the most frequent cancer types in Western societies and predominately occurs in the elderly male. The strong age-related increase of prostate cancer is associated with a progressive accumulation of oxidative DNA damage which is presumably supported by a decline of the cellular antioxidative defence during ageing. Risk of developing prostate cancer is much lower in many Asian countries where soy food is an integral part of diet. Therefore, isoflavones from soy were suggested to have chemopreventive activities in prostate cells. Here, we have investigated the hypothesis that the soy-isoflavone genistein could protect DNA of LAPC-4 prostate cells from oxidative stress-related damage by enhancing the expression of antioxidative genes and proteins. A 24 h preincubation with genistein (1-30 mu M) protected cells from hydrogen peroxide-induced DNA damage, as determined by the comet assay. Analysis of two cDNA macroarrays, each containing 96 genes of biotransformation and stress response, revealed a modulated expression of 3 genes at 1 mu M and of 19 genes at 10 mu M genistein. Real-time PCR confirmed the induction of three genes encoding products with antioxidant activities, namely glutathione reductase (2.7-fold), microsomal glutathione S-transferase 1 (1.9-fold) and metallothionein 1X (6.3-fold), at 1-30 mu M genistein. 17 beta-Estradiol, in contrast, decreased the expression of metallothionein 1X at 0.3 mu M (2.0-fold), possibly pointing to an estrogen receptor-mediated regulation of this gene. Immunocytochemical staining revealed an induction of metallothionein proteins at 30 mu M genistein, while their intracellular localization was unaffected. Metallothioneins were previously found to protect cells from hydrogen peroxide-induced DNA damage. Hence, our findings indicate that genistein protects prostate cells from oxidative stress-related DNA damage presumably by inducing the expression of antioxidative products, such as metallothioneins. Genistein, therefore, might counteract the age-related decline of important antioxidative defence systems which in turn maintain DNA integrity.