Limits...
Cytochrome P450 1A2 Metabolizes 17β-Estradiol to Suppress Hepatocellular Carcinoma.

Ren J, Chen GG, Liu Y, Su X, Hu B, Leung BC, Wang Y, Ho RL, Yang S, Lu G, Lee CG, Lai PB - PLoS ONE (2016)

Bottom Line: The inhibitory effect was significantly enhanced in cells with CYP1A2 overexpression, which effectively conversed E2 to the cytotoxic 2-ME.The anti-HCC effect of E2 was not associated with estrogen receptors ERα and ERβ as well as tumor suppressor P53 but enhanced by the approved anti-HCC drug sorafenib.The reduction of CYP1A2 significantly disrupts this metabolic pathway, contributing the progression and growth of HCC and the gender disparity of this malignancy.

View Article: PubMed Central - PubMed

Affiliation: Department of Surgery, Faculty of Medicine, The Chinese University of Hong Kong; New Territories, Hong Kong, China.

ABSTRACT
Hepatocellular carcinoma (HCC) occurs more frequently in men than in women. It is commonly agreed that estrogen plays important roles in suppressing HCC development, however, the underlying mechanism remains largely unknown. Since estrogen is mainly metabolized in liver and its metabolites affect cell proliferation, we sought to investigate if the liver-specific cytochrome P450 1A2 (CYP1A2) mediated the inhibitory effect of estrogen on HCC. In this study, the expression of estrogen-metabolizing enzyme CYP1A2 was determined in HCC tissues and cell lines. Cell proliferation and apoptosis were assessed in cells with or without CYP1A2 overexpression. The levels of 17β-estradiol (E2) and its metabolite 2-methoxyestradiol (2-ME) were determined. A xenograft tumor model in mice was established to confirm the findings. It was found that CYP1A2 expression was greatly repressed in HCC. E2 suppressed HCC cell proliferation and xenograft tumor development by inducing apoptosis. The inhibitory effect was significantly enhanced in cells with CYP1A2 overexpression, which effectively conversed E2 to the cytotoxic 2-ME. E2 in combination with sorafenib showed an additive effect on HCC. The anti-HCC effect of E2 was not associated with estrogen receptors ERα and ERβ as well as tumor suppressor P53 but enhanced by the approved anti-HCC drug sorafenib. In addition, HDAC inhibitors greatly induced CYP1A2 promoter activities in cancer cells, especially liver cancer cells, but not in non-tumorigenic cells. Collectively, CYP1A2 metabolizes E2 to generate the potent anti-tumor agent 2-ME in HCC. The reduction of CYP1A2 significantly disrupts this metabolic pathway, contributing the progression and growth of HCC and the gender disparity of this malignancy.

No MeSH data available.


Related in: MedlinePlus

The expression of CYP1A2 was regulated by HDAC inhibitors.(A)CYP1A2 promoter is activated by HDAC inhibitors. Hep3B cells were transfected with luciferase reporter plasmids and then treated for 24 hours with the drugs of the following concentrations before being harvested for Luc assays: 2μM SAHA, 1μM TSA, 5mM sodium butyrate (NaB), 5mM VPA, 0.2μg/ml doxorubicin, 2μM camptothecin, 5μM decitabine, 5μM zebularine, and 10μM etoposide. The concentrations were determined in preliminary cell proliferation assays in which the drugs caused obvious changes in cell growth. The data are expressed as fold changes of luc reading relative to that of vehicle-treated cells of same transfection (control). Each column represents the mean ± s.d. of three independent experiments. (B) Inductive effect of HDAC inhibitor on CYP1A2 promoter is higher in cancer cells. Tumorigenic (Hep3B, PCL/PRF/5, Huh7, H1299, MCF7) or non-tumorigenic (MIHA, LO2, 293T) cells were transfected with CYP1A2 promoter-luciferase reporter plasmids and treated with 2μM SAHA for 24 hours before being harvested for Luc assays. The data are expressed as fold changes of luc reading relative to that of vehicle-treated cells (control). Each column represents the mean ± s.d. of three independent experiments. (C) Different HDAC inhibitors exert different effects on CYP1A2 promoter activity. The data are expressed as fold changes of luc reading relative to that of vehicle-treated cells (control). Concentrations of the drugs were determined by referring to the reported Half Maximal Inhibitory Concentrations (IC50) of the inhibitors against various HDAC proteins. (D) Expression levels of “classical” HDAC genes in HCC cells and non-tumorigenic cells. The expression levels were normalized with β-Actin mRNA levels. Each column represents the mean ± s.d. of four technical replicates. (E) Hypothesis on how E2 contributes to the clearance of carcinogen-damaged cells and consequently suppresses carcinogenesis.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4836701&req=5

pone.0153863.g005: The expression of CYP1A2 was regulated by HDAC inhibitors.(A)CYP1A2 promoter is activated by HDAC inhibitors. Hep3B cells were transfected with luciferase reporter plasmids and then treated for 24 hours with the drugs of the following concentrations before being harvested for Luc assays: 2μM SAHA, 1μM TSA, 5mM sodium butyrate (NaB), 5mM VPA, 0.2μg/ml doxorubicin, 2μM camptothecin, 5μM decitabine, 5μM zebularine, and 10μM etoposide. The concentrations were determined in preliminary cell proliferation assays in which the drugs caused obvious changes in cell growth. The data are expressed as fold changes of luc reading relative to that of vehicle-treated cells of same transfection (control). Each column represents the mean ± s.d. of three independent experiments. (B) Inductive effect of HDAC inhibitor on CYP1A2 promoter is higher in cancer cells. Tumorigenic (Hep3B, PCL/PRF/5, Huh7, H1299, MCF7) or non-tumorigenic (MIHA, LO2, 293T) cells were transfected with CYP1A2 promoter-luciferase reporter plasmids and treated with 2μM SAHA for 24 hours before being harvested for Luc assays. The data are expressed as fold changes of luc reading relative to that of vehicle-treated cells (control). Each column represents the mean ± s.d. of three independent experiments. (C) Different HDAC inhibitors exert different effects on CYP1A2 promoter activity. The data are expressed as fold changes of luc reading relative to that of vehicle-treated cells (control). Concentrations of the drugs were determined by referring to the reported Half Maximal Inhibitory Concentrations (IC50) of the inhibitors against various HDAC proteins. (D) Expression levels of “classical” HDAC genes in HCC cells and non-tumorigenic cells. The expression levels were normalized with β-Actin mRNA levels. Each column represents the mean ± s.d. of four technical replicates. (E) Hypothesis on how E2 contributes to the clearance of carcinogen-damaged cells and consequently suppresses carcinogenesis.

Mentions: The mechanism underlying the suppression of CYP1A2 expression in HCC was also investigated. The 5kb promoter region upstream of the CYP1A2 TSS was cloned in a luciferase (Luc) reporter vector. It was found that the promoter activity could be greatly induced by all the four HDAC inhibitors in the experiment, suberoylanilide hydroxamic acid (SAHA), trichostatin A (TSA), sodium butyrate (NaB), Valproic acid (VPA), but not by inhibitors against other chromatin modifying enzymes, such as doxorubicin, camptothecin, etoposide (Topoisomerase inhibitors), decitabine (5-aza-2'-deoxycytidine) and zebularine (DNA methyltransferase inhibitors) “Fig 5A”. More interestingly, the induction effect of HDAC inhibitors on CYP1A2 promoter was much more robust in cancer cells (Hep3B, PCL/PRF/5, Huh7, H1299, MCF7) than that in non-tumorigenic cell lines (MIHA, LO2, 293T) and the strongest induction was observed in HCC cells Hep3B, PCL/PRF/5 and Huh7 “Fig 5B”.


Cytochrome P450 1A2 Metabolizes 17β-Estradiol to Suppress Hepatocellular Carcinoma.

Ren J, Chen GG, Liu Y, Su X, Hu B, Leung BC, Wang Y, Ho RL, Yang S, Lu G, Lee CG, Lai PB - PLoS ONE (2016)

The expression of CYP1A2 was regulated by HDAC inhibitors.(A)CYP1A2 promoter is activated by HDAC inhibitors. Hep3B cells were transfected with luciferase reporter plasmids and then treated for 24 hours with the drugs of the following concentrations before being harvested for Luc assays: 2μM SAHA, 1μM TSA, 5mM sodium butyrate (NaB), 5mM VPA, 0.2μg/ml doxorubicin, 2μM camptothecin, 5μM decitabine, 5μM zebularine, and 10μM etoposide. The concentrations were determined in preliminary cell proliferation assays in which the drugs caused obvious changes in cell growth. The data are expressed as fold changes of luc reading relative to that of vehicle-treated cells of same transfection (control). Each column represents the mean ± s.d. of three independent experiments. (B) Inductive effect of HDAC inhibitor on CYP1A2 promoter is higher in cancer cells. Tumorigenic (Hep3B, PCL/PRF/5, Huh7, H1299, MCF7) or non-tumorigenic (MIHA, LO2, 293T) cells were transfected with CYP1A2 promoter-luciferase reporter plasmids and treated with 2μM SAHA for 24 hours before being harvested for Luc assays. The data are expressed as fold changes of luc reading relative to that of vehicle-treated cells (control). Each column represents the mean ± s.d. of three independent experiments. (C) Different HDAC inhibitors exert different effects on CYP1A2 promoter activity. The data are expressed as fold changes of luc reading relative to that of vehicle-treated cells (control). Concentrations of the drugs were determined by referring to the reported Half Maximal Inhibitory Concentrations (IC50) of the inhibitors against various HDAC proteins. (D) Expression levels of “classical” HDAC genes in HCC cells and non-tumorigenic cells. The expression levels were normalized with β-Actin mRNA levels. Each column represents the mean ± s.d. of four technical replicates. (E) Hypothesis on how E2 contributes to the clearance of carcinogen-damaged cells and consequently suppresses carcinogenesis.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4836701&req=5

pone.0153863.g005: The expression of CYP1A2 was regulated by HDAC inhibitors.(A)CYP1A2 promoter is activated by HDAC inhibitors. Hep3B cells were transfected with luciferase reporter plasmids and then treated for 24 hours with the drugs of the following concentrations before being harvested for Luc assays: 2μM SAHA, 1μM TSA, 5mM sodium butyrate (NaB), 5mM VPA, 0.2μg/ml doxorubicin, 2μM camptothecin, 5μM decitabine, 5μM zebularine, and 10μM etoposide. The concentrations were determined in preliminary cell proliferation assays in which the drugs caused obvious changes in cell growth. The data are expressed as fold changes of luc reading relative to that of vehicle-treated cells of same transfection (control). Each column represents the mean ± s.d. of three independent experiments. (B) Inductive effect of HDAC inhibitor on CYP1A2 promoter is higher in cancer cells. Tumorigenic (Hep3B, PCL/PRF/5, Huh7, H1299, MCF7) or non-tumorigenic (MIHA, LO2, 293T) cells were transfected with CYP1A2 promoter-luciferase reporter plasmids and treated with 2μM SAHA for 24 hours before being harvested for Luc assays. The data are expressed as fold changes of luc reading relative to that of vehicle-treated cells (control). Each column represents the mean ± s.d. of three independent experiments. (C) Different HDAC inhibitors exert different effects on CYP1A2 promoter activity. The data are expressed as fold changes of luc reading relative to that of vehicle-treated cells (control). Concentrations of the drugs were determined by referring to the reported Half Maximal Inhibitory Concentrations (IC50) of the inhibitors against various HDAC proteins. (D) Expression levels of “classical” HDAC genes in HCC cells and non-tumorigenic cells. The expression levels were normalized with β-Actin mRNA levels. Each column represents the mean ± s.d. of four technical replicates. (E) Hypothesis on how E2 contributes to the clearance of carcinogen-damaged cells and consequently suppresses carcinogenesis.
Mentions: The mechanism underlying the suppression of CYP1A2 expression in HCC was also investigated. The 5kb promoter region upstream of the CYP1A2 TSS was cloned in a luciferase (Luc) reporter vector. It was found that the promoter activity could be greatly induced by all the four HDAC inhibitors in the experiment, suberoylanilide hydroxamic acid (SAHA), trichostatin A (TSA), sodium butyrate (NaB), Valproic acid (VPA), but not by inhibitors against other chromatin modifying enzymes, such as doxorubicin, camptothecin, etoposide (Topoisomerase inhibitors), decitabine (5-aza-2'-deoxycytidine) and zebularine (DNA methyltransferase inhibitors) “Fig 5A”. More interestingly, the induction effect of HDAC inhibitors on CYP1A2 promoter was much more robust in cancer cells (Hep3B, PCL/PRF/5, Huh7, H1299, MCF7) than that in non-tumorigenic cell lines (MIHA, LO2, 293T) and the strongest induction was observed in HCC cells Hep3B, PCL/PRF/5 and Huh7 “Fig 5B”.

Bottom Line: The inhibitory effect was significantly enhanced in cells with CYP1A2 overexpression, which effectively conversed E2 to the cytotoxic 2-ME.The anti-HCC effect of E2 was not associated with estrogen receptors ERα and ERβ as well as tumor suppressor P53 but enhanced by the approved anti-HCC drug sorafenib.The reduction of CYP1A2 significantly disrupts this metabolic pathway, contributing the progression and growth of HCC and the gender disparity of this malignancy.

View Article: PubMed Central - PubMed

Affiliation: Department of Surgery, Faculty of Medicine, The Chinese University of Hong Kong; New Territories, Hong Kong, China.

ABSTRACT
Hepatocellular carcinoma (HCC) occurs more frequently in men than in women. It is commonly agreed that estrogen plays important roles in suppressing HCC development, however, the underlying mechanism remains largely unknown. Since estrogen is mainly metabolized in liver and its metabolites affect cell proliferation, we sought to investigate if the liver-specific cytochrome P450 1A2 (CYP1A2) mediated the inhibitory effect of estrogen on HCC. In this study, the expression of estrogen-metabolizing enzyme CYP1A2 was determined in HCC tissues and cell lines. Cell proliferation and apoptosis were assessed in cells with or without CYP1A2 overexpression. The levels of 17β-estradiol (E2) and its metabolite 2-methoxyestradiol (2-ME) were determined. A xenograft tumor model in mice was established to confirm the findings. It was found that CYP1A2 expression was greatly repressed in HCC. E2 suppressed HCC cell proliferation and xenograft tumor development by inducing apoptosis. The inhibitory effect was significantly enhanced in cells with CYP1A2 overexpression, which effectively conversed E2 to the cytotoxic 2-ME. E2 in combination with sorafenib showed an additive effect on HCC. The anti-HCC effect of E2 was not associated with estrogen receptors ERα and ERβ as well as tumor suppressor P53 but enhanced by the approved anti-HCC drug sorafenib. In addition, HDAC inhibitors greatly induced CYP1A2 promoter activities in cancer cells, especially liver cancer cells, but not in non-tumorigenic cells. Collectively, CYP1A2 metabolizes E2 to generate the potent anti-tumor agent 2-ME in HCC. The reduction of CYP1A2 significantly disrupts this metabolic pathway, contributing the progression and growth of HCC and the gender disparity of this malignancy.

No MeSH data available.


Related in: MedlinePlus