Carcinogen-induced histone alteration in normal human mammary epithelial cells
Carcinogen-induced histone alteration in normal human mammary epithelial cells
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DOI：
10.1093/carcin/bgm100
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发表时间：
2007-10-01
期刊：
影响因子：
4.7
通讯作者：
Parl, Fritz F.
中科院分区：
文献类型：
--
作者：
Bradley, Chastity;van der Meer, Riet;Parl, Fritz F.
对乳腺上皮中早期致癌物诱导的蛋白质改变知之甚少。早期改变的检测将增强我们对早期癌变的理解。在这里，正常人乳腺上皮细胞（HMEC）暴露于饮食和环境致癌物[2-氨基-1甲基-6-苯基咪唑[4，5 b]吡啶（PhIP），4-氨基联苯（ABP），苯并[α]芘，2，3，7，8-四氯二苯并-p-二恶英]单独或组合。单链可变片段抗体的噬菌体展示文库用于筛选通过治疗改变的蛋白质靶。结合基质辅助激光解吸飞行时间，我们确定组蛋白H3作为靶抗原。虽然组蛋白H3总蛋白在对照和处理的HMEC中保持不变，但赖氨酸4的甲基化发生了改变。与对照HMEC相比，在处理的HMEC中观察到单甲基组蛋白H3（Lys 4）的减少。这种变化取决于致癌物浓度，对PhIP和ABP具有特异性。为了表征潜在的组蛋白去甲基化机制，分析了赖氨酸特异性去甲基化酶1（LSD 1）的定位和蛋白表达模式。在对照HMEC中，LSD 1存在于核周边。然而，72小时的致癌物处理后，LSD 1定位在细胞核内。在处理后48小时内，单甲基组蛋白H3（Lys 4）恢复和LSD 1定位逆转。与对照HMEC相比，处理的HMEC中LSD 1的蛋白表达水平也增加。我们的数据表明，一个单一的酶，LSD 1的诱导，代表了致癌物暴露的早期反应，这导致组蛋白H3（赖氨酸4）的去甲基化，这反过来可能会影响多个基因的表达在早期乳腺癌的发生。
Little is known about early carcinogen-induced protein alterations in mammary epithelium. Detection of early alterations would enhance our understanding of early-stage carcinogenesis. Here, normal human mammary epithelial cells (HMECs) were exposed to dietary and environmental carcinogens [2-amino-1methyl- 6- phenylimidazo[4,5b] pyridine (PhIP), 4-aminobiphenyl (ABP), benzo[alpha] pyrene, 2,3,7,8-tetrachlorodibenzo-p-dioxin] individually or in combination. A phage display library of single-chain variable fragment antibodies was used to screen protein targets altered by the treatment. In combination with matrix-assisted laser desorption time of flight, we identified histone H3 as a target antigen. Although histone H3 total protein remained unchanged in control and treated HMEC, the methylation of lysine 4 was altered. A reduction in mono-methyl histone H3 (Lys 4) was observed in treated HMEC compared with control HMEC. This alteration was shown to be dependent on carcinogen concentration and specific for PhIP and ABP. To characterize potential histone demethylation mechanisms, localization and protein expression patterns of lysine-specific demethylase 1 (LSD1) were analyzed. In control HMEC, LSD1 was present at the nuclear periphery. However, following 72 h carcinogen treatment, LSD1 localized within the nucleus. Within 48 h after treatment, monomethyl histone H3 (Lys 4) was restored and LSD1 localization was reversed. Protein expression levels of LSD1 were also increased in treated HMEC compared with control HMEC. Our data suggest that the induction of a single enzyme, LSD1, represents an early response to carcinogen exposure, which leads to the demethylation of histone H3 (Lys 4), which, in turn, may influence the expression of multiple genes critical in early-stage mammary carcinogenesis.