Immunochemical studies for the presence of P-450 HFLa, a form of cytochrome P-450 in human fetal livers in human hepatocellular carcinoma cells.

Kitada, Munehiro; Tsukidate, Kazuo; Takeuchi, Jun; Taneda, M; Komori, Masaharu; Ohi, Hiroshi; Itahashi, Koshiro; Kamataki, Tetsuya

doi:10.1248/bpb1978.12.341

“…Although others have now characterized maintenance and regulation of some CYP450s (including total generic CYP3A) in primary human hepatocyte culture (38,391, little attention has been given to 3A multiplicity. This study documents exclusive expression of 3A7 protein and mRNA in HepG2 cells and is thus consistent with the detection of 3A7(HFLa) in a primary human hepatoblastoma (40). It is now clear that the dexamethasone-inducible 3A gene family we had previously reported to be in HepG2 cells was 3A7 (8).…”

Section: Discussionsupporting

confidence: 89%

Regulation of human liver cytochromes P-450 in family 3A in primary and continuous culture of human hepatocytes

Schuetz¹

1993

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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)

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“…Our immunohistochemical studies using anti-P-450 HFLa antibodies have shown that P-450 HFLa was detectable in various tissues of gynecologic malignancies (Okajima et al, 1988) and hepatocellular carcinomas (Kitada et al, 1989b). This finding may indicate that P-450 HFLa is one of the onco-feto-placental antigens.…”

Section: Resultsmentioning

confidence: 72%

Fetus-specific expression of a form of cytochrome P-450 in human livers

Komori

¹

,

Nishio²,

Kitada³

et al. 1990

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The developmentally regulated expression of forms of cytochrome P-450, namely, those encoded by lambda HFL33 and NF25 or HLp cDNAs, which were isolated from respective fetal and adult human liver cDNA libraries, was investigated. When EcoRI fragments of cDNA clones of lambda HFL33 and NF25 were used as probes, these probes hybridized with RNA from both fetal and adult human livers. However, when oligonucleotides specific to the coding and 3'-noncoding region of lambda HFL33 (oli-HFL and oli-HFL3', respectively) were used as probes, these probes gave hybridizable bands with RNA from fetal but not adult livers. On the other hand, an oligonucleotide probe specific to the coding region of NF25 and HLp (oli-NF) gave positive bands with RNA only from adult livers. These results indicate that P-450(HFL33) is expressed specifically in fetal livers and that neither P-450NF nor HLp is expressed in fetal livers, but one or both are expressed in adult livers.

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Regulation of human liver cytochromes P-450 in family 3A in primary and continuous culture of human hepatocytes

Schuetz

¹

,

Schuetz

²

,

Strom

³

et al. 1993

View full text Add to dashboard Cite

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)

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Immunochemical studies for the presence of P-450 HFLa, a form of cytochrome P-450 in human fetal livers in human hepatocellular carcinoma cells.

Cited by 9 publications

References 12 publications

Regulation of human liver cytochromes P-450 in family 3A in primary and continuous culture of human hepatocytes

Regulation of human liver cytochromes P-450 in family 3A in primary and continuous culture of human hepatocytes

Fetus-specific expression of a form of cytochrome P-450 in human livers

Regulation of human liver cytochromes P-450 in family 3A in primary and continuous culture of human hepatocytes

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