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Honjo K, Hamada T, Yoshimura T, Yokoyama S, Yamada S, Tan YQ, Leung LK, Nakamura N, Ohi Y, Higashi M, Tanimoto A. PCP4/PEP19 upregulates aromatase gene expression via CYP19A1 promoter I.1 in human breast cancer SK-BR-3 cells. Oncotarget 2018; 9:29619-29633. [PMID: 30038708 PMCID: PMC6049867 DOI: 10.18632/oncotarget.25651] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 05/23/2018] [Indexed: 12/24/2022] Open
Abstract
The Purkinje cell protein 4/peptide 19 (PCP4/PEP19) is a novel breast cancer cell expressing peptide, originally found in the neural cells as an anti-apoptotic factor, could inhibit cell apoptosis and enhance cell migration and invasion in human breast cancer cell lines. The expression of PCP4/PEP19 is induced by estrogens in estrogen receptor-positive (ER+) MCF-7 cells but also highly expressed in ER- SK-BR-3 cells. In this study, we investigated the effects of PCP4/PEP19 on aromatase gene expression in MCF-7 and SK-BR-3 human breast cancer cells. In SK-BR-3 cells but not in MCF-7 cells, PCP4/PEP19 knockdown by siRNA silencing decreased the aromatase expression in gene transcriptional level. When PCP4/PEP19 was overexpressed by CMV promoter-driven PCP4/PEP19 expressing plasmid transfection, aromatase gene transcription increased in SK-BR-3 cells. This aromatase gene transcription is mainly mediated through promoter region PI.1, which is usually active in the placental tissue but not in the breast cancer tissue. These results indicate a new function of PCP4/PEP19 that would enhance aromatase gene upregulation to supply estrogens in heterogeneous cancer microenvironment.
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Affiliation(s)
- Kie Honjo
- Department of Oral Surgery, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Taiji Hamada
- Department of Pathology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Takuya Yoshimura
- Department of Oral Surgery, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Seiya Yokoyama
- Department of Pathology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Sohsuke Yamada
- Department of Pathology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.,Department of Pathology and Laboratory Medicine, Kanazawa Medical University, Ishikawa, Japan
| | - Yan-Qin Tan
- Faculty of Science, School of Life Sciences, Food and Nutritional Science Programme, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Lai K Leung
- Faculty of Science, School of Life Sciences, Food and Nutritional Science Programme, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Norifumi Nakamura
- Department of Oral Surgery, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Yasuyo Ohi
- Department of Pathology, Sagara Hospital, Social Medical Corporation Hakuaikai, Kagoshima, Japan
| | - Michiyo Higashi
- Department of Pathology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Akihide Tanimoto
- Department of Pathology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
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Kim MJ, Park YJ, Chung KH, Oh SM. The Inhibitory Effects of the Standardized Extracts of Ginkgo biloba
on Aromatase Activity in JEG-3 Human Choriocarcinoma Cells. Phytother Res 2013; 27:1756-62. [DOI: 10.1002/ptr.4927] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2012] [Revised: 12/18/2012] [Accepted: 12/18/2012] [Indexed: 11/09/2022]
Affiliation(s)
- Mi Jie Kim
- School of Pharmacy; Sungkyunkwan University; 300 Cheoncheon dong Jangan-gu, Suwon Kyeonggi-do 440-746 South Korea
| | - Yong Joo Park
- School of Pharmacy; Sungkyunkwan University; 300 Cheoncheon dong Jangan-gu, Suwon Kyeonggi-do 440-746 South Korea
| | - Kyu Hyuck Chung
- School of Pharmacy; Sungkyunkwan University; 300 Cheoncheon dong Jangan-gu, Suwon Kyeonggi-do 440-746 South Korea
| | - Seung Min Oh
- Hoseo Fusion Technology Laboratory; Hoseo University; 165 Sechul-ri, Asan ChungcheongNam-do 336-795 South Korea
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Ghai S, Monga R, Mohanty T, Chauhan M, Singh D. Term placenta shows methylation independent down regulation of Cyp19 gene in animals with retained fetal membranes. Res Vet Sci 2012; 92:53-9. [DOI: 10.1016/j.rvsc.2010.10.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2010] [Revised: 10/02/2010] [Accepted: 10/14/2010] [Indexed: 11/15/2022]
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Lu L, Zhang H, Lv N, Ma X, Tian L, Hu X, Liu S, Xu M, Weng Q, Watanabe G, Taya K. Immunolocalization of Androgen Receptor, Aromatase Cytochrome P450, Estrogen Receptor Alpha and Estrogen Receptor Beta Proteins during the Breeding Season in Scent Glands of Muskrats (Ondatra zibethicus). Zoolog Sci 2011; 28:727-32. [DOI: 10.2108/zsj.28.727] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Wang Y, Ye L, Leung LK. A positive feedback pathway of estrogen biosynthesis in breast cancer cells is contained by resveratrol. Toxicology 2008; 248:130-5. [PMID: 18462857 DOI: 10.1016/j.tox.2008.03.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2008] [Revised: 03/19/2008] [Accepted: 03/24/2008] [Indexed: 10/22/2022]
Abstract
Cytochrome P450 (CYP) 19 enzyme or aromatase catalyses the rate-determining step of estrogen synthesis. The transcriptional control of CYP19 gene is highly specific in different cell types, for instance, Promoter I.3/II is commonly used for regulation in breast cancer cells. Recently, a positive feedback pathway for estrogen synthesis has been identified in ER alpha expressing SK-BR-3 cells. CYP19 mRNA abundance and activity are increased in this pathway and the promoter usage is switched from Promoter I.3/II to I.1 through a non-genomic process. In the present study, effect of the phytocompound resveratrol on this Promoter I.1-controlled expression of aromatase was investigated. Results indicated that resveratrol reduced the estradiol-induced mRNA abundance in SK-BR-3 cells expressing ER alpha. Luciferase reporter gene assays revealed that resveratrol could also repress the transcriptional control dictated by Promoter I.1. Since the ERE-driven luciferase activity was not repressed by resveratrol, the nuclear events of estrogen were unlikely to be suppressed by resveratrol. Instead the phytochemical reduced the amount of ERK activated by estradiol, which could be the pathway responsible for Promoter I.1 transactivation and the induced CYP19 expression. The present study illustrated that resveratrol impeded the non-genomic induction of estrogen on CYP19.
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Affiliation(s)
- Yun Wang
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, China
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Ferrini JB, Rodrigues E, Dulic V, Pichard-Garcia L, Fabr JM, Blanc P, Maurel P. Expression and DNA-binding activity of C/EBPalpha and C/EBPbeta in human liver and differentiated primary hepatocytes. J Hepatol 2001; 35:170-7. [PMID: 11580138 DOI: 10.1016/s0168-8278(01)00112-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
BACKGROUND/AIMS Limited information is available on the expression and role of C/EBP factors in human liver and hepatocytes. We investigated the expression and DNA-binding activity of C/EBPalpha and C/EBPbeta in human liver needle biopsies, surgical lobectomies and differentiated cultured hepatocytes derived from lobectomies. METHODS RNA and protein extracts were analyzed by RNAse protection, immunoblot and gel shift assays. RESULTS C/EBP mRNAs, isoforms and DNA-binding activities were low/undetectable in lobectomies. In contrast, several C/EBPalpha (47, 45, 35 and 33 kDa) and C/EBPbeta isoforms (47, 43, 40, 35 and 21 kDa) were observed in needle biopsies. In cultured hepatocytes, the C/EBP expression pattern dramatically changed with time. C/EBPalpha mRNA and the 45 kDa isoform increased in parallel, reaching a maximum after 3-4 weeks coincident with weak DNA-binding activity. C/EBPbeta mRNA and isoform expression increased rapidly reaching a plateau within 1-2 weeks; all C/EBPbeta isoforms were phosphorylated. C/EBPbeta exhibited greater DNA-binding activity than C/EBPalpha, and this activity paralleled C/EBPbeta isoform expression. CONCLUSIONS C/EBP isoforms exhibit markedly different expression patterns in lobectomies, needle biopsies and cultured hepatocytes. Stress stimuli during and/or after surgery for lobectomy resections may account for this difference. The pattern of C/EBP isoform expression in long-term highly differentiated cultured hepatocytes is close to that observed in needle biopsies.
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Affiliation(s)
- J B Ferrini
- INSERM U128, CNRS IFR24, Montpellier, France
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McTernan PG, Anwar A, Eggo MC, Barnett AH, Stewart PM, Kumar S. Gender differences in the regulation of P450 aromatase expression and activity in human adipose tissue. Int J Obes (Lond) 2000; 24:875-81. [PMID: 10918534 DOI: 10.1038/sj.ijo.0801254] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To investigate the hormonal regulation of P450 aromatase activity (responsible for the conversion of C19 androgens to C18 oestrogens) in human adipose tissue from men and pre- and post-menopausal women. SUBJECTS Subcutaneous abdominal adipose tissue was obtained from 19 subjects: six pre-menopausal females (mean age 41.8+/-(s.e.m.) 2.5; mean weight 76.01+/-5.6 kg), eight post-menopausal females (mean age 59.9+/-2.0; mean weight 63.5+/-2.6 kg), and five males (mean age 35.8+/-8.8; mean weight 78.5+/-7.8 kg) undergoing elective or cosmetic surgery. MEASUREMENTS Cell viability and cell size were determined using staining techniques. RT-PCR was used to confirm the presence of aromatase. The regulation of aromatase activity was characterized using androstenedione as a substrate in a tritiated water release assay. Aromatase activity was analysed in abdominal subcutaneous stromal cells (ASC) and mature adipocytes (AD) cultured in serum-free medium with cortisol (10-6-10-7 M), insulin (500 nM) or a combination of both. RESULTS In ASC aromatase activity increased in females from 14.5+/-1.7 to 29. 3+/-2.6 pmol/mg/h (n=14, P<0.05) and to 25.2+/-2.1 pmol/mg/h with cortisol (10-7 M) and insulin, respectively (P<0.05). In males ASC basal aromatase activity (20.5+/-4.2 pmol/mg/h; n=5) was inhibited by cortisol (10-7 M) alone (12.3+/-1.8 pmol/mg/h) and in combination with insulin (6.6+/-1.2 pmol/mg/h; men vs women, P<0.005). Aromatase activity in mature adipocytes was stimulated by cortisol plus insulin (P<0.05) with no gender-specific differences. Treatment of ASC from both pre- and post-menopausal females with cortisol alone (10-6 M; 10-7 M) or in combination with insulin demonstrated significantly different aromatase regulation compared with male aromatase stromal cell regulation (P<0.05); however there were no differences in aromatase regulation between pre- and post-menopausal females either in stromal cells or adipocytes. CONCLUSION This study shows intrinsic gender differences in the regulation of aromatase, suggesting that differential enzyme regulation may affect sex steroid metabolism to alter the pattern of fat distribution between the sexes.
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Affiliation(s)
- P G McTernan
- Department of Medicine, University of Birmingham, Queen Elizabeth Hospital and Birmingham Heartlands Hospital, Birmingham B15 2TH, UK.
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Shozu M, Zhao Y, Simpson ER. TGF-beta1 stimulates expression of the aromatase (CYP19) gene in human osteoblast-like cells and THP-1 cells. Mol Cell Endocrinol 2000; 160:123-33. [PMID: 10715546 DOI: 10.1016/s0303-7207(99)00233-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Recent evidence has shown that bone is not only a target of estrogen action but also a source of local estrogen production. Bone cells such as osteoblasts express aromatase (P450arom) and the expression of P450arom in osteoblasts is positively regulated in a tissue specific fashion, as in the case of other tissues which express P450arom. To clarify the physiological factors regulating expression of P450arom in bone, we tested TGF-beta1 using osteoblast-like cells obtained from human fetuses as well as THP-1 cells. TGF-beta1 increased IL-1beta+DEX- induced aromatase activity in osteoblast-like cells, while it inhibited activity in skin fibroblasts. Similar enhancement of aromatase activity by TGF-beta1 was found in DEX-stimulated THP-1 cells and this cell line was used for further experiments. In THP-1 cells, TGF-beta1 enhanced DEX-induced aromatase activity almost linearly by 12 h and thereafter. Increased levels of P450arom transcripts were also demonstrated by RT-PCR at 3 h of TGF-beta1 treatment and thereafter. Cyclohexamide abolished enhancement of activity but did not inhibit the accumulation of P450arom transcripts induced by TGF-beta1. Increase in P450arom expression by TGF-beta1 was attributable to expression driven by promoter I.4. TGF-beta1 did not change the half life of P450arom transcripts. To identify the cis-acting elements responsible for TGF-beta1 action on aromatase expression, transient transfection assays were performed using a series of deletion constructs for promoter I.4 (P450-I.4/Luc). Two constructs (-410/+14 and-340/+14) that contain a functional glucocorticoid response element (GRE) and downstream sequence showed significant increase of luciferase activity in response to TGF-beta1. Deletion and mutation of the GRE in P450-I.4/Luc (-340/+14) abolished the TGF-beta1. The luciferase activity of a (GRE)(1)-SV40/Luc construct was also stimulated by TGF-beta1. These results indicate that TGF-beta1 increases the expression of P450arom at the level of transcription through promoter I.4, at least in part via an enhancement of transactivation activity of the GR in THP-1 cells. TGF-beta1 is suggested to be one of the physiological up-regulatory factors of bone aromatase.
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Affiliation(s)
- M Shozu
- Cecil H. and Ida Green Center for Reproductive Biology Sciences, The University of Texas Southwestern Medical Center, Dallas, TX 75235-9050, USA
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Yamakoshi Y, Kishimoto T, Sugimura K, Kawashima H. Human prostate CYP3A5: identification of a unique 5'-untranslated sequence and characterization of purified recombinant protein. Biochem Biophys Res Commun 1999; 260:676-81. [PMID: 10403825 DOI: 10.1006/bbrc.1999.0960] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have isolated a cDNA clone coding for CYP3A5 from a human prostate cDNA library. The human prostate CYP3A5 cDNA had a unique 5'-untranslated sequence, suggesting that the prostate specific regulation of CYP3A5 is different from liver. Hybridization screening using a human genomic BAC library yielded four positive clones, two of which were shown to contain the unique 5'-untranslated sequence by Southern blot analysis. The CYP3A5 recombinant protein expressed in Escherichia coli using the pCWOri expression vector was purified to an almost electrophoretically homogeneous state with a specific content of 4.4 nmol of P450/mg of protein. This P450 exhibited 6beta-hydroxylation activity toward both testosterone and progesterone. No polar metabolite of 5alpha-dihydrotestosterone (DHT) was detected. The apparent K(m) values for testosterone and progesterone 6beta-hydroxylation were 143 and 114 microM, respectively, with V(max) values of 0.48 and 0. 21 nmol/min/nmol of P450, respectively. This is the first report that a particular form of P450, CYP3A5, has been isolated from human prostate and that the purified recombinant protein of CYP3A5 has been shown to be active in the metabolism of sex hormones.
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Affiliation(s)
- Y Yamakoshi
- Department of Urology, Osaka City University Medical School, Osaka, 545-8585, Japan
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Roe AL, Warren G, Hou G, Howard G, Shedlofsky SI, Blouin RA. The effect of high dose endotoxin on CYP3A2 expression in the rat. Pharm Res 1998; 15:1603-8. [PMID: 9794504 DOI: 10.1023/a:1011915402914] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE The purpose of our research was two-fold: 1) to further characterize the downregulation of CYP3A2 mRNA, protein, and activity during an acute phase response (APR); 2) most importantly, to relate the time-dependent activation of nuclear proteins to putative DNA binding sequences within the CYP3A2 5'-flanking region, with the loss in CYP3A2 expression. METHODS Rats were injected (2.0 mg/animal, i.p.) with LPS and sacrificed at 1, 2, 4, 6, 8, 24, 48, and 72 hours. Hepatic nuclear protein was isolated and analyzed for binding activity to AP-1, NFkappaB, and NF-IL6 consensus sequences. Hepatic CYP3A2 mRNA levels were determined by solution hybridization and CYP3A2 protein, CYP3A2 activity, and total P450 were measured in hepatic microsomes. RESULTS Computer analysis of the 5'-flanking region of CYP3A2 revealed the presence of 5 NF-IL6 and 4 AP-1 putative DNA binding sites. The strongest increase in AP-1 binding activity occurred between 6 and 24 hr, and the alteration in binding complexes to an NF-IL6 oligonucleotide occurred between 4 and 24 hr. Maximum loss in CYP3A2 mRNA occurred at 8 hr post-LPS injection and remained lowered at the 24 hr timepoint. CYP3A2 protein was significantly decreased at 24, 48, and 72 hours post-LPS treatment with corresponding decreases in CYP3A2 activity and total P450. CONCLUSIONS The changes in NF-IL6 and AP-1 binding after LPS treatment, which appears to correlate with the changes in CYP3A2 mRNA, combined with the presence of putative NF-IL6 and AP-1 sites located in the CYP3A25'-flanking region, may indicate a potential role for NF-IL6 and AP-1 in CYP3A2 downregulation during an APR.
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Affiliation(s)
- A L Roe
- Graduate Center for Toxicology, University of Kentucky, Lexington, USA
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Shozu M, Zhao Y, Bulun SE, Simpson ER. Multiple splicing events involved in regulation of human aromatase expression by a novel promoter, I.6. Endocrinology 1998; 139:1610-7. [PMID: 9528941 DOI: 10.1210/endo.139.4.5878] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The expression of aromatase is regulated in a tissue-specific fashion through alternative use of multiple promoter-specific first exons. To date, eight different first exons have been reported in human aromatase, namely I.1., I.2, I.3. I.4, I.5, PII, 2a, and 1f. Recently, we have found a new putative exon I in a RACE-generated library of THP-1 cells and have conducted studies to characterize this new exon I. We confirmed that the constructs containing -1552/+17 or less flanking sequence of this exon function as a promoter in THP-1 cells, JEG-3 cells and osteoblast-like cells obtained from a human fetus. Results of transfection assays using a series of deletion constructs and mutation constructs indicate that a 1-bp mismatch of the consensus TATA-like box (TTTAAT) and the consensus sequence of the initiator site, which is located 45 bp downstream of the putative TATA box, were functioning cooperatively as a core promoter. The putative transcription site was confirmed by the results of RT-PCR southern blot analysis. We examined the regulation and the expression of this exon, I.6, in several human cells and tissues by RT-PCR Southern blot analysis. THP-1 cells (mononuclear leukemic origin) and JEG-3 cells (choriocarcinoma origin) expressed exon I.6 in serum-free media. The level of expression was increased by serum and phorbol myristyl acetate (PMA) in both cell lines. Adipose stromal cells also expressed exon I.6 in the presence of PMA. In fetal osteoblasts, the expression of exon I.6 was increased most effectively by serum and less so by dexamethasone (DEX) + IL-1beta and DEX + IL-11, whereas induction by serum was suppressed by the addition of DEX. The level of expression was low in granulosa cells in culture and did not change with forskolin. On the other hand, dibutyryl cAMP suppressed PMA-stimulated expression of exon I.6 in THP-1 cells and adipose stromal cells. This result supports the hypothesis that the expression of exon I.6 is regulated mainly via an AP-1 binding site that is found upstream of the initiator site of the promoter region. Expression of exon I.6-specific transcripts was examined in several human tissues. Testis and bone obtained from normal adults expressed exon I.6. Testicular tumor and hepatic carcinoma expressed high levels of exon I.6, whereas granulosa cell tumor did not. Fetal liver and bone also showed a significant level of exon I.6 expression, but not so much as testicular tumor and hepatic tumor. Several splicing variants of exon I.6 were detected especially in THP-1 and JEG-3 cells, and to a lesser extent in primary cultures and tissue samples. These variants were identified as an unspliced form, a form spliced at the end of exon I.4, a form spliced at the end of exon I.3 (truncated) and a form spliced 220 bp downstream of the 3' end of exon I.6. The last variant revealed a new splicing site. Because most of the splicing variants contain the sequence specific for exon I.3, RT-PCR specific for exon I.3 can coamplify these splicing variants of exon I.6 transcripts. These results suggests that it is necessary to examine the expression of I.6 in tissues that are known to express exon I.3 such as breast adipose tissue, in which promoter usage of exon I of the aromatase gene switches from exon I.4 to I.3 in the course of malignant transformation.
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Affiliation(s)
- M Shozu
- Cecil H. and Ida Green Center for Reproductive Biology Sciences, and Department of Obstetrics/Gynecology, The University of Texas Southwestern Medical Center, Dallas 75235-9051, USA
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Sun T, Zhao Y, Mangelsdorf DJ, Simpson ER. Characterization of a region upstream of exon I.1 of the human CYP19 (aromatase) gene that mediates regulation by retinoids in human choriocarcinoma cells. Endocrinology 1998; 139:1684-91. [PMID: 9528950 DOI: 10.1210/endo.139.4.5959] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The biosynthesis of estrogens is catalyzed by aromatase P450 (P450arom), the product of the CYP19 gene. The tissue-specific expression of the CYP19 gene is regulated by means of tissue-specific promoters through the use of alternative splicing mechanisms. Thus, transcripts containing various 5'-untranslated termini are present in ovary, brain, adipose stromal cells, and placenta. Sequence corresponding to untranslated exon I.1 is present uniquely in 5'-termini of transcripts expressed in human placenta and choriocarcinoma cells, as a consequence of expression driven by a distal promoter, I.1. The goal of the present study was the identification of regulatory elements in this promoter region. Various deletion mutations of the upstream flanking region of exon I.1 were constructed using the PCR or restriction enzyme digestion. The genomic fragments were fused upstream of the luciferase reporter gene. These constructs were transfected into human choriocarcinoma (JEG3) cells. The longest construct employed, -924/+10 bp, expressed the highest luciferase reporter gene activity. The -64/+10 bp and -125/+10 bp constructs showed no reporter gene expression. Transfection of the -201/+10 bp construct resulted in reporter gene expression, but at a lower level than that of the -924/+10 bp construct, and this expression was induced by serum as well as by LG69 and TTNPB, ligands specific for RXR and RAR respectively, as well as by vitamin D. These results parallel the actions of the ligands on aromatase activity. Mutation or deletion of an imperfect palindromic sequence (AGGTCATGCCCC) located at -183 to -172 bp upstream of the transcriptional start site of exon I.1 resulted in loss of basal- and retinoid-induced reporter gene expression. Gel retardation analysis using nuclear extracts of JEG3 cells treated with retinoids and the imperfect palindromic sequence as probe, showed that proteins present in the nuclear extracts bound to this sequence in a specific fashion. The binding activities were elevated by incubation of the cells with LG69 and TTNPB, ligands specific for RXR and RAR respectively. Binding of nuclear proteins to the palindromic sequence was displaced either by anti-RXR alpha serum or by anti-VDR serum, suggesting the formation of a heterodimer of RXR alpha and VDR. These results suggest that the imperfect palindromic sequence upstream of exon I.1 plays an important but novel role in the regulated expression of the CYP19 gene in choriocarcinoma cells.
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Affiliation(s)
- T Sun
- Cecil H. and Ida Green Center for Reproductive Biology Sciences, Dallas, Texas 75235-9051, USA
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Abstract
Through the cloning of two transcription factors named NF-IL6 and STAT3/APRF, two types of IL-6 signal transduction pathways from the cell surface to the nucleus have been revealed. NF-IL6 is phosphorylated and activated by a Ras-dependent MAP kinase cascade, while STAT3/APRF is directly tyrosine-phosphorylated by JAK kinases that associate with the cytoplasmic portion of the receptor, and translocates to the nucleus and activates transcription (JAK-STAT pathway). STAT3 is also tyrosine phosphorylated in response to epidermal growth factor (EGF), granulocyte colony-stimulating factor (G-CSF), leptin and other IL-6-type cytokines including ciliary neurotrophic factor (CNTF), oncostatin M and leukemia inhibitory factor (LIF). Mice deficient in the genes for NF-IL6 and STAT3 were generated. NF-IL6 mice were highly susceptible to facultative intracellular bacteria owing to ineffective killing of the pathogens by the macrophages. Futhermore, the tumor cytotoxicity of macrophages from NF-IL6 KO mice was severely impaired. These results demonstrate a crucial role of NF-IL6 in macrophage bactericidal and tumoricidal activities. The target disruption of STAT3 resulted in embryonic lethality prior to gastrulation, demonstrating that STAT3 is essential for the early development of mouse embryos.
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Affiliation(s)
- S Akira
- Department of Biochemistry, Hyogo College of Medicine, Japan
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14
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Abstract
Hepatic P450 activities are profoundly affected by various infectious and inflammatory stimuli, and this has clinical and toxicological consequences. Whereas the expression of most P450s in the liver is suppressed, some are induced. Many of the effects observed in vivo can be mimicked by pro-inflammatory cytokines and IFNs, and P450s are differentially regulated by these agents. Therefore, different cytokine profiles and concentrations in the vicinity of the hepatocyte in different models of inflammation may result in qualitatively and quantitatively different effects on populations of P450s. In addition to cytokines, glucocorticoids may have an important role in P450 regulation in stress conditions, including that caused by inflammatory stimuli. Although in many cases the decreases in activity are due primarily to a down-regulation of P450 gene transcription, it is likely that modulation of RNA and protein turnover, as well as enzyme inhibition, contributes to some of the observed effects. The mechanisms whereby these effects are produced may also vary with both the P450 under study and the time course of the effect. The complexity of the P450 response to inflammation and infection means that all of the above factors must be considered when trying to predict the effect of a given infectious or inflammatory condition on the clinical or toxic response of humans or animals to an administered drug or toxin. The question of whether the down-regulation of the hepatic P450 system to inflammation or infection is a homeostatic or pathological response cannot be answered at present. It is difficult to discern the physiological benefit of reducing hepatic P450 activities, unless it is to prevent the generation of reactive oxygen species generated by uncoupled catalytic turnover of the enzymes. On the other hand, as we proposed some years ago [64], the suppression of P450 may be due to the liver's need to utilize its transcriptional machinery and energy for the synthesis of APPs involved in the inflammatory response. In that case, one could ask why the organism has gone to the trouble of employing differential mechanisms for suppression of P450. One answer could be that the response evolved after the divergence of many of the P450 genes, necessitating the evolution of multiple redundant mechanisms for P450 suppression. In contrast to the down-regulation of P450s in the liver, the induction of several forms in this and other tissues suggests a more specific homeostatic role of these effects, e.g., in generation or catabolism of bioactive metabolites.
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Affiliation(s)
- E T Morgan
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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Stephanou A, Okosi A, Knight RA, Chowdrey HS, Latchman DS. C/EBP activates the human corticotropin-releasing hormone gene promoter. Mol Cell Endocrinol 1997; 134:41-50. [PMID: 9406848 DOI: 10.1016/s0303-7207(97)00170-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The purpose of these studies was to identify whether transcription factors, associated with cytokine signalling, affected promoter activity of the corticotropin releasing hormone (CRH) gene. Fragments of a 3.6 kb sequence of the human CRH gene promoter were amplified by PCR and ligated upstream of a CAT reporter. These constructs were transfected into a variety of cell lines, either alone or together, with transcription factor expression vectors. Basal activity of a 3070 bp CRH promoter fragment was only seen in neuronal and lymphoblastoid cell lines. Promoter activity was increased by the transcription factors C/EBPbeta (NF-IL6) and more strongly, by C/EBPdelta (NF-IL6beta). Increased CRH promoter activity following phorbol ester treatment was inhibited by a dominant negative NF-IL6 mutant, showing that the effects of phorbol ester were principally mediated by C/EBP. Moreover, the inverse changes in the expression of CRH in the hypothalamus and spleens of arthritic rats were paralleled by similar inverse changes in NF-IL6beta expression in these organs. These data show that some transcription factors associated with cytokine signalling can also activate the CRH promoter.
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Affiliation(s)
- A Stephanou
- Department of Molecular Pathology, University College London, UK
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Fürbass R, Kalbe C, Vanselow J. Tissue-specific expression of the bovine aromatase-encoding gene uses multiple transcriptional start sites and alternative first exons. Endocrinology 1997; 138:2813-9. [PMID: 9202222 DOI: 10.1210/endo.138.7.5257] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Here we report on the genomic structure of the bovine aromatase cytochrome P450-encoding gene (Cyp19) and its tissue-specific transcript variants. The gene comprises at least 14 exons (1.1, 1.2a, 1.2b, 1.3,1.4, and 2-10) spanning more than 56 kilobases of genomic DNA. The coding area is confined to exons 2-10. Transcriptional start sites of Cyp19 were examined in granulosa cells, placenta, testis, adrenal gland, and brain, employing 5'-RACE (rapid amplification of complementary DNA ends) and primer extension. The analysis of 5'-RACE clones revealed six Cyp19 transcript variants that were different within their 5'-untranslated regions (5'-UTR). Yet, the coding region was identical in all clones. Although two of these 5'-UTR (the first 152 nucleotides of exon 2 and exon 1.4) are conserved among different species, four others (exons 1.1, 1.2a, 1.2b, and 1.3) did not show sequence homology to any other species. Transcription from exons 1.1 and 2 starts at several adjacent sites. In granulosa cells and placenta, but not in brain, a fraction of transcripts starting with exon 1.2a contains an additional untranslated exon, 1.2b, due to alternative splicing. Transcript variants comprising exon 1.1, 1.2a, 1.2b, or 1.3 were mainly found in the placenta, those with the 5'-UTR of exon 2 were predominant in granulosa cells, and transcripts with exon 1.4 prevailed in the brain. Estimates of Cyp19 transcript concentrations in six different tissues revealed high levels in granulosa cells and placenta, intermediate levels in testis and brain, and low levels in adrenal gland and liver. Our experiments demonstrate that six transcript variants of the bovine Cyp19 gene, including 9-11 exons, are expressed with tissue-specific preferences. These transcripts are presumably generated using five different promoter regions and tissue-specific alternative splicing.
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Affiliation(s)
- R Fürbass
- Research Institute for the Biology of Farm Animals, Dummerstorf, Germany.
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Abstract
Endometriosis is a complex and intriguing disease. If retrograde menstruation normally occurs, then why do all women not develop endometriosis? The exact prevalence of endometriosis is unknown; however, a 20% to 90% prevalency rate has been reported in women with pelvic pain and infertility. This article reviews the factors involved.
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Affiliation(s)
- J A Hill
- Department of Obstetrics, Gynecology, and Reproductive Biology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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Kawashima H, Sequeira DJ, Nelson DR, Strobel HW. Genomic cloning and protein expression of a novel rat brain cytochrome P-450 CYP2D18* catalyzing imipramine N-demethylation. J Biol Chem 1996; 271:28176-80. [PMID: 8910433 DOI: 10.1074/jbc.271.45.28176] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
We have previously reported the isolation of two cDNA clones, designated 2d-29 and 2d-35, which have identical open reading frames and code for a novel brain cytochrome P-450 (P-450) belonging to the CYP2D subfamily, and noted that the mRNA of clone 2d-35 seems to be expressed in the brain but not in the liver (1). Although the deduced amino acid sequence of these clones differs from that of the liver CYP2D4 by only 5 amino acids distributed in the C-terminal region, this new P-450 cDNA clone contained a unique 5'-extension, and we posit in this report by analysis of a genomic clone that this 5'-untranslated sequence is derived from a gene distinct from that of CYP2D4. Thus, this novel P-450 was named P-450 2D18 according to the recommended nomenclature (2). The expressibility of this cDNA was confirmed by in vitro translation using a reticulocyte system, and protein expression was performed using COS-M6 cells. Immunoblot analysis showed a cross-reacting band of the predicted size range with anti-P-450 2D6 antiserum, which was not seen in control cells. Furthermore, the CYP2D18-expressed COS cell lysate showed N-demethylation activity toward imipramine, whereas another brain P-450 CYP4F6-expressed COS cell lysate showed 10-hydroxylation activity. This is the first report that associates an individual P-450 isozyme in brain with a particular metabolic alteration of the antidepressant imipramine.
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Affiliation(s)
- H Kawashima
- Department of Biochemistry and Molecular Biology, The University of Texas Medical School at Houston, Houston, Texas 77225, USA
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