Esfahani M, Hathotuwegama S, Kalenak A, Scerbo L, Brown H M
Biochem Biophys Res Commun. 1987 May 14;144(3):1167-74. doi: 10.1016/0006-291x(87)91434-3.
The human monocyte/macrophage-like cell line U937, which is a cholesterol auxotroph, is nonadherent. However, it becomes adherent after treatment with phorbol 12-myristate 13-acetate (phorbol ester). We investigated the effects of cellular cholesterol depletion and repletion on the effectiveness of phorbol ester to induce adhesion to substratum. Almost 70% of cellular cholesterol is depleted by incubation of the cells for 24 hrs in the growth medium in which delipidated fetal calf serum is substituted for fetal calf serum without affecting viability or the rate of growth. The use of delipidated fetal calf serum inhibited phorbol ester-induced adhesion by 40%. If the cells were preincubated in the medium containing delipidated fetal calf serum 6 hrs prior to addition of phorbol ester, adhesion was inhibited by 90%. Addition of cholesterol to the medium containing delipidated fetal calf serum, which replenishes cellular cholesterol, restored the ability of phorbol ester to induce adhesion to levels seen in cells cultured in the medium containing fetal calf serum. Epicholesterol was not as effective as cholesterol in supporting adhesion. Cholesterol depletion did not inhibit phorbol ester stimulation of superoxide anion production. These observations indicate a function for cholesterol in phorbol ester-induced adhesion that is independent of phorbol ester-induced superoxide anion production. It is proposed that cholesterol is required for synthesis and/or proper orientation and distribution, in the plasma membrane, of macromolecule(s) that mediate phorbol ester-induced adhesion.
人单核细胞/巨噬细胞样细胞系U937是一种胆固醇营养缺陷型细胞，呈非贴壁状态。然而，在用佛波醇12 - 肉豆蔻酸酯13 - 乙酸酯（佛波酯）处理后，它会变为贴壁状态。我们研究了细胞胆固醇耗竭和补充对佛波酯诱导细胞贴壁于基质有效性的影响。通过在生长培养基中培养细胞24小时，用脱脂胎牛血清替代胎牛血清，可使细胞中近70%的胆固醇耗竭，且不影响细胞活力或生长速率。使用脱脂胎牛血清可使佛波酯诱导的贴壁抑制40%。如果在添加佛波酯前6小时将细胞预先在含有脱脂胎牛血清的培养基中孵育，贴壁抑制率可达90%。向含有脱脂胎牛血清的培养基中添加胆固醇以补充细胞胆固醇，可使佛波酯诱导贴壁的能力恢复到在含有胎牛血清的培养基中培养的细胞所观察到的水平。表胆固醇在支持贴壁方面不如胆固醇有效。胆固醇耗竭并不抑制佛波酯对超氧阴离子产生的刺激作用。这些观察结果表明胆固醇在佛波酯诱导的贴壁中具有一种功能，该功能独立于佛波酯诱导的超氧阴离子产生。有人提出，胆固醇对于介导佛波酯诱导贴壁的大分子在质膜中的合成和/或正确定向及分布是必需的。
