Fairbanks K P, Witte L D, Goodman D S
J Biol Chem. 1984 Feb 10;259(3):1546-51.
Relationships between mevalonate and DNA synthesis were explored in quiescent human fibroblasts stimulated with human platelet-derived growth factor (PDGF). Studies of others have indicated that mevalonate, or a product of mevalonate other than cholesterol, is essential for DNA replication. The present studies were designed to determine whether there was a critical time in the cell cycle when mevalonate was necessary for later DNA synthesis to occur. Compactin and mevinolin, inhibitors of hydroxymethylglutaryl CoA reductase, were employed to block both the synthesis of mevalonate and of DNA. Compactin inhibited the sharp peak of DNA synthesis which occurs in cells 24 h after PDGF addition in a concentration-dependent manner. This suppression of DNA synthesis was not prevented by low density lipoprotein but was fully reversed by mevalonate. Compactin inhibited DNA synthesis when the inhibitor was present during the time interval 10-20 h after PDGF addition. Its presence only in the interval before 10 h or after 20 h had no effect. Conversely, mevalonate could fully overcome the compactin block in DNA synthesis when present during the period of from 10-20 h after PDGF addition. Mevalonate present only before 10 h or after 20 h had no effect. When mevalonate was added to mevinolin-blocked cells for the interval 10-15 h after PDGF, the mevinolin block of DNA synthesis was 68% overcome; in contrast, only 20% of the reversal of the mevinolin block was seen when mevalonate was added from 15-20 h. Addition of mevalonate for only the 2-h interval of from 10-12 h after PDGF overcame the mevinolin block of DNA synthesis (assayed at 24 h) by 50%. The results show that there is a critical time period, several h before S phase, when PDGF-stimulated cells require mevalonate in order for DNA synthesis to proceed at 24 h. This critical period comprised the interval of approximately 10-20 h after PDGF addition and especially the early part of this interval.
在用人血小板衍生生长因子（PDGF）刺激的静止人成纤维细胞中，研究了甲羟戊酸与DNA合成之间的关系。其他研究表明，甲羟戊酸或甲羟戊酸除胆固醇以外的产物对于DNA复制至关重要。本研究旨在确定细胞周期中是否存在一个关键时间点，此时甲羟戊酸对于后续DNA合成的发生是必需的。采用洛伐他汀和辛伐他汀（羟甲基戊二酰辅酶A还原酶抑制剂）来阻断甲羟戊酸和DNA的合成。洛伐他汀以浓度依赖的方式抑制在添加PDGF后24小时细胞中出现的DNA合成尖峰。低密度脂蛋白不能阻止这种对DNA合成的抑制，但甲羟戊酸可使其完全逆转。当在添加PDGF后10 - 20小时的时间间隔内存在抑制剂时，洛伐他汀抑制DNA合成。仅在10小时之前或20小时之后的时间段内存在它则没有影响。相反，当在添加PDGF后10 - 20小时期间存在甲羟戊酸时，它可以完全克服洛伐他汀对DNA合成的阻断。仅在10小时之前或20小时之后存在甲羟戊酸则没有影响。当在添加PDGF后10 - 15小时的时间间隔内向被辛伐他汀阻断的细胞中添加甲羟戊酸时，辛伐他汀对DNA合成的阻断有68%被克服；相比之下，当在15 - 20小时添加甲羟戊酸时，仅观察到辛伐他汀阻断逆转的20%。在添加PDGF后仅在10 - 12小时的2小时时间间隔内添加甲羟戊酸可克服辛伐他汀对DNA合成的阻断（在24小时测定）达50%。结果表明，在S期前数小时存在一个关键时间段，此时PDGF刺激的细胞需要甲羟戊酸以便在24小时进行DNA合成。这个关键时期包括添加PDGF后大约10 - 20小时的时间段，尤其是该时间段的早期部分。
