Gal D, MacDonald P C, Porter J C, Smith J W, Simpson E R
Cancer Res. 1981 Feb;41(2):473-7.
Cholesterol metabolism in four gynecological cancer cell lines in monolayer culture was evaluated as a function of cell density. The rate of uptake and degradation of [125I]iodinated low-density lipoprotein increased during the first 24 to 48 hr of culture, but decreased thereafter. Once the cells became confluent, the rate of metabolism of [125I]iodinated low-density lipoprotein was only one-tenth that in cells which were in the preconfluent state. The specific activity of 3-hydroxy-3-methylglutaryl coenzyme reductase increased during the first 24 to 48 hr of culture and subsequently declined, reaching a nadir after confluency was attained. The rate of incorporation of [14C]oleate into cholesteryl esters was low when the cells were in the log-exponential phase of replication but increased gradually as cell density increased. The highest specific activity of acylcoenzyme A: cholesterol acyltransferase was attained after the cells became confluent. Generally speaking, there was an inverse relationship between the specific activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase, on the one hand, and the rate of [125I]iodinated low-density lipoprotein metabolism and cholesteryl ester synthesis, on the other. It is concluded that cholesterol metabolism in cancer cells in monolayer culture is regulated, in part, by the rate of cell division. In the cancer cells utilized in this study, it is apparent that cholesterol metabolism was subject to the same regulatory mechanisms as are present in nonneoplastic cells.
在单层培养的四种妇科癌细胞系中，评估胆固醇代谢作为细胞密度的函数。在培养的最初24至48小时内，[125I]碘化低密度脂蛋白的摄取和降解速率增加，但此后下降。一旦细胞汇合，[125I]碘化低密度脂蛋白的代谢速率仅为处于汇合前状态细胞的十分之一。3-羟基-3-甲基戊二酰辅酶A还原酶的比活性在培养的最初24至48小时内增加，随后下降，在达到汇合后达到最低点。当细胞处于对数指数增殖期时，[14C]油酸掺入胆固醇酯的速率较低，但随着细胞密度增加而逐渐增加。酰基辅酶A：胆固醇酰基转移酶的最高比活性在细胞汇合后达到。一般来说，一方面3-羟基-3-甲基戊二酰辅酶A还原酶的比活性与另一方面[125I]碘化低密度脂蛋白代谢速率和胆固醇酯合成速率之间存在反比关系。得出结论，单层培养的癌细胞中的胆固醇代谢部分受细胞分裂速率调节。在本研究中使用的癌细胞中，显然胆固醇代谢受与非肿瘤细胞中相同的调节机制支配。
