Lactate dehydrogenase-B is silenced by promoter methylation in a high frequency of human breast cancers.
Lactate dehydrogenase-B is silenced by promoter methylation in a high frequency of human breast cancers.
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DOI：
10.1371/journal.pone.0057697
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发表时间：
2013
期刊：
影响因子：
3.7
通讯作者：
Rehman I
中科院分区：
文献类型：
--
作者：
Brown NJ;Higham SE;Perunovic B;Arafa M;Balasubramanian S;Rehman I
在常氧条件下，非恶性细胞依靠氧化磷酸化产生ATP，而癌细胞依靠糖酵解；这种现象被称为沃伯格效应。我们的目的是阐明Warburg效应在人类乳腺癌中的作用机制。乳酸脱氢酶（LDH）同工酶的酶谱分析。通过细胞中的逆转录PCR和乳腺组织中的免疫组织化学检测ldl - b亚基表达。通过亚硫酸氢盐修饰DNA测序来评估LDH-B启动子甲基化。T-47D和MCF7细胞中LDH同工酶1-4的表达缺失或减少。T-47D细胞中LDH-B mRNA缺失，用去甲基化剂5′氮杂胞苷处理后其表达恢复。在T-47D和MCF7细胞以及25/ 25的乳腺癌组织中发现了LDH-B启动子甲基化，但在5/ 5的正常乳腺组织中没有发现。LDH-B蛋白在23/ 26（88%）乳腺癌和4/8相邻导管原位癌中均无免疫表达（<10%细胞染色）。乳腺癌细胞暴露于缺氧（1% O2） 48小时后，MCF7细胞（14.0倍，p = 0.002）和T-47D细胞（2.9倍，p = 0.009）的乳酸水平显著增加，但MDA-MB-436细胞（-0.9倍，p = 0.229）或MCF10AT细胞（1.2倍，p = 0.09）的乳酸水平没有显著增加。在人类乳腺癌中，由于启动子甲基化导致ldl - b表达缺失是一种早期和频繁发生的事件，并且可能导致缺氧条件下癌细胞糖酵解的增强。
Under normoxia, non-malignant cells rely on oxidative phosphorylation for their ATP production, whereas cancer cells rely on Glycolysis; a phenomenon known as the Warburg effect. We aimed to elucidate the mechanisms contributing to the Warburg effect in human breast cancer. Lactate Dehydrogenase (LDH) isoenzymes were profiled using zymography. LDH-B subunit expression was assessed by reverse transcription PCR in cells, and by Immunohistochemistry in breast tissues. LDH-B promoter methylation was assessed by sequencing bisulfite modified DNA. Absent or decreased expression of LDH isoenzymes 1-4, were seen in T-47D and MCF7 cells. Absence of LDH-B mRNA was seen in T-47D cells, and its expression was restored following treatment with the demethylating agent 5'Azacytadine. LDH-B promoter methylation was identified in T-47D and MCF7 cells, and in 25/ 25 cases of breast cancer tissues, but not in 5/ 5 cases of normal breast tissues. Absent immuno-expression of LDH-B protein (<10% cells stained), was seen in 23/ 26 (88%) breast cancer cases, and in 4/8 cases of adjacent ductal carcinoma in situ lesions. Exposure of breast cancer cells to hypoxia (1% O2), for 48 hours resulted in significant increases in lactate levels in both MCF7 (14.0 fold, p = 0.002), and T-47D cells (2.9 fold, p = 0.009), but not in MDA-MB-436 (-0.9 fold, p = 0.229), or MCF10AT (1.2 fold, p = 0.09) cells. Loss of LDH-B expression is an early and frequent event in human breast cancer occurring due to promoter methylation, and is likely to contribute to an enhanced glycolysis of cancer cells under hypoxia.
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影响因子：
4.3
作者：
Draoui N;Feron O
通讯作者：
Feron O
影响因子：
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作者：
Leiblich, A.;Cross, S. S.;Rehman, I.
通讯作者：
Rehman, I.
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作者：
Liao, Alex C.;Li, Chien-Feng;Wu, Ting-Feng
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作者：
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Sugihara, Kenichi
影响因子：
56.9
作者：
MARKERT, CL
通讯作者：
MARKERT, CL