Schuetz E G, Schuetz J D, Strom S C, Thompson M T, Fisher R A, Molowa D T, Li D, Guzelian P S
Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee 38101.
Hepatology. 1993 Nov;18(5):1254-62.
The cytochrome P-450 3A gene family comprises the dominant forms of cytochrome P-450 found in human liver. We examined as a possible useful system for studying the regulation of cytochrome P-450 3A under controlled conditions in vitro, primary monolayer cultures of human hepatocytes and compared the results with those obtained from the study of cytochrome P-450 3A in the human hepatoblastoma cell line HepG2 or in the human hepatocellular carcinoma cell line TONG/HCC. Using 3A antibodies, 3A cDNAs and 3A3, 3A4, 3A5 and 3A7 isozyme-specific oligonucleotides as probes, we determined that primary human hepatocyte cultures routinely expressed a 3A3/4* immunoreactive protein and 3A mRNA. These gene products were well maintained for many days and were induced by treatment of the cultures with dexamethasone, phenobarbital, macrolide antibiotics, the HMG CoA reductase inhibitor lovastatin or an antifungal agent, clotrimazole. Of six donor livers examined, only two contained mRNA or protein for 3A5, a form found in only a few adult human subjects. In cultures prepared from one of these two livers, 3A5 mRNA was detectable for several days. In cultures of hepatocytes from the remaining four human livers that did not contain 3A5 mRNA or protein, we detected neither spontaneous nor inducible 3A5 proteins or mRNAs. HepG2 cells contained only 3A7 protein, a form found in human fetal liver, even after treatment with inducers. treatment of HepG2 cells with dexamethasone, macrolide antibiotics, phenobarbital and phenobarbital-like inducers or lovastatin produced dose-dependent induction of 3A7 mRNA and 3A7 immunoreactive protein. TONG/HCC cells contained 3A3, 3A4 and 3A5 mRNAs, but only 3A5 immunoreactive protein could be detected.(ABSTRACT TRUNCATED AT 250 WORDS)
细胞色素P - 450 3A基因家族包含在人肝脏中发现的细胞色素P - 450的主要形式。我们研究了人肝细胞原代单层培养物，将其作为在体外可控条件下研究细胞色素P - 450 3A调控的一个可能有用的系统，并将结果与在人肝母细胞瘤细胞系HepG2或人肝细胞癌细胞系TONG/HCC中对细胞色素P - 450 3A的研究结果进行比较。使用3A抗体、3A cDNA以及3A3、3A4、3A5和3A7同工酶特异性寡核苷酸作为探针，我们确定人肝细胞原代培养物通常表达一种3A3/4*免疫反应性蛋白和3A mRNA。这些基因产物能在许多天内很好地维持，并通过用地塞米松、苯巴比妥、大环内酯类抗生素、HMG CoA还原酶抑制剂洛伐他汀或抗真菌剂克霉唑处理培养物而被诱导。在所检测的六个供体肝脏中，只有两个含有3A5的mRNA或蛋白质，3A5这种形式仅在少数成年人类个体中发现。在由这两个肝脏之一制备的培养物中，3A5 mRNA能在数天内被检测到。在来自其余四个不含有3A5 mRNA或蛋白质的人肝脏的肝细胞培养物中，我们既未检测到自发的也未检测到可诱导的3A5蛋白质或mRNA。HepG2细胞只含有3A7蛋白，这是在人胎儿肝脏中发现的一种形式，即使在用诱导剂处理后也是如此。用地塞米松、大环内酯类抗生素、苯巴比妥和类苯巴比妥诱导剂或洛伐他汀处理HepG2细胞会产生3A7 mRNA和3A7免疫反应性蛋白的剂量依赖性诱导。TONG/HCC细胞含有3A3、3A4和3A5 mRNA，但只能检测到3A5免疫反应性蛋白。（摘要截短于250字）
