Expression of NAD(P)H:Quinone oxidoreductase 1 in HeLa cells -: Role of hydrogen peroxide and growth phase
Expression of NAD(P)H:Quinone oxidoreductase 1 in HeLa cells -: Role of hydrogen peroxide and growth phase
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DOI：
10.1074/jbc.m107168200
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发表时间：
2001-11-30
影响因子：
4.8
通讯作者：
Villalba, JM
中科院分区：
文献类型：
--
作者：
Bello, RI;Gómez-Díaz, C;Villalba, JM
这项工作的目的是研究 H2O2 在 NAD(P)H:醌氧化还原酶 1（NQO1、DT-黄酶、EC 1.6.99.2）调节中的作用，与 HeLa 细胞培养物的细胞密度以及 NQO1 在这些细胞中发挥的功能有关。汇合 HeLa 细胞中的 NQO1 活性水平比稀疏细胞高得多（40 倍），前者细胞对 H2O2 的抵抗力更强。添加亚致死浓度的 H2O2（高达 24 μM）可使稀疏细胞中的 NQO1 显着增加（12 μM 时高达 16 倍），但对汇合细胞没有影响。当细胞在丙酮酸（一种 H2O2 清除剂）存在下达到汇合时，与没有丙酮酸时生长汇合的培养物相比，NQO1 活性降低。双香豆素对醌还原酶的抑制显着降低了无血清培养基中汇合细胞的活力。这是首次证明 H2O2 对 NQO1 表达的调节取决于 HeLa 细胞中的细胞密度，并且随着细胞密度较高，内源生成的 H2O2 参与 NQO1 活性的增加。这种酶是促进汇合细胞存活所必需的。
The aim of this work was to study the role of H2O2 in the regulation of NAD(P)H:quinone oxidoreductase 1 (NQO1, DT-diaphorase, EC 1.6.99.2) with relation to cell density of HeLa cells cultures and the function played by NQO1 in these cells. Levels of NQO1 activity were much higher (40-fold) in confluent HeLa cells than in sparse cells, the former cells being much more resistant to H2O2. Addition of sublethal concentrations of H2O2 (up to 24 muM) produced a significant increase of NQO1 (up to 16-fold at 12 muM) in sparse cells but had no effect in confluent cells. When cells reached confluency in the presence of pyruvate, a H2O2 scavenger, NQO1 activity was decreased compared with cultures grown to confluency without pyruvate. Inhibition of quinone reductases by dicumarol substantially decreased viability of confluent cells in serum-free medium. This is the first demonstration that regulation of NQO1 expression by H2O2 is dependent on the cell density in HeLa cells and that endogenous generation of H2O2 participates in the increase of NQO1 activity as cell density is higher. This enzyme is required to promote survival of confluent cells.