Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0596263 (carcinogenesis)
 64,820 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cyclooxygenases (Cox) are prostaglandin synthetase enzymes which play a key role in mammary carcinogenesis. Several connections were demonstrated between Cox and a few oncogenes (v-src, v-Ha-ras, HER-2/neu, Wnt, p53 mutated), alimentary products (PUFAs), transcription factors (c-jun and c-fos), proapoptotic proteins [Bax et Bcl-x(L)] or antiapoptotic (Bcl-2), CYP19 aromatase gene, NFkappaB receptor (RANKL), angiogenesis (via VEGF, TXA2, oxid nitric synthetase, alphaVbeta3 integrin receptor), peroxisome gamma proliferator receptor (PPARgamma) and its ligand PGJ2 and with antitubuline chemotherapy drugs. No correlation of Cox2 expression with hormonal receptors was shown. In epidemiologic studies there is evidence of breast cancer risk reduction for women who take AINS for a long time. Alimentary factors like resveratrol or insaturated fat acid reduce Cox2 expression in animal and could be investigated in human studies. Clinical trials are planed with the anti Cox2 celecoxib for breast cancer prevention, in adjuvant setting, in metastatic situation combined with exemestane or antitubulin drugs or in neoadjuvant therapy.
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PMID:[Cyclooxygenase 2 and breast cancer. From biological concepts to therapeutic trials]. 1523 37

Carcinogenesis of the prostate involves androgen influences, and associations between genetic polymorphisms of androgen receptor and metabolizing enzymes and prostate cancer risk have been reported. Roles for non-androgenic hormones are not well defined, but they also may have an impact judging from epidemiological and animal experimental alphalambda zeta of data. The purpose of the study was to determine whether hormone-related polymorphisms are associated with prostate cancer risk. A case-control study was performed with 147 Japanese prostate cancer patients and 266 urological controls. Polymorphisms of target genes [cytochrome P450 (CYP) 1B1, Leu432Val; debrisoquine hydroxylase, (CYP2D6)*4; aromatase (CYP19), Arg264Cys; estrogen receptor (ER)alpha-Xx (Xba I) and Pp (Pvu II); ERbeta-Rr (Rsa I); progesterone receptor (PR) Alu in intron 7] were examined by PCR-based methods. The capital and small letters signify the absence and presence of restriction sites, respectively. Odds ratios (OR) were adjusted for age using multiple logistic regression analysis with SPSS Medical Pack. Among the seven examined genetic polymorphisms, significant associations between CYP1B1 Leu432Val (OR 4.80; 95% confidence interval (CI), 1.21-19.05) and Alu in intron 7 of PR (OR 4.17; 95%CI, 1.26-13.85) were found. As for combined effects, the CYP1B1 polymorphisms (Leu/Val+Val/Val) together with heterozygosity for Alu in the PR were more frequent among prostate cancer patients (1.45%) than controls (0.41%), although without significance (OR, 3.99; 95%CI, 0.36-44.8). The combination of ERalpha (P/p+p/p) polymorphisms with heterozygosity for Alu in the PR demonstrated an OR of 4.56 (95%CI, 1.01-20.6). This pilot study showed that CYP1B1 and PR polymorphisms, alone or in combination, might be associated with prostate cancer risk. They might, therefore, have potential as a tool for identifying high-risk individuals.
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PMID:Genetic polymorphisms of hormone-related genes and prostate cancer risk in the Japanese population. 1533 Jan 95

Aromatase is a key enzyme in steroidogenesis and plays an important role in sexual differentiation, fertility, and carcinogenesis. Importantly, a variety of chemicals in the environment may influence its activity and thereby disrupt endocrine function. In the current studies, we developed a novel nonradioactive method for measuring aromatase activity that uses a specific ELISA for estrone along with KGN human ovary granulosa-like carcinoma cells. This cell line has relatively high aromatase activity, and because it lacks 17alpha-hydroxylase, it secretes little or no androstenedione, 17beta-estradiol, or estrone. Therefore, aromatase activity can be assayed simply by measuring the production of estrone in the culture medium after addition of the substrate, androstenedione. Furthermore, by making a slight change in the commercial ELISA kit and optimizing the experimental conditions, we developed a sensitive aromatase assay that could measure a wide range of estrone concentrations with very low interference by androgens. We used this assay to investigate the effects of 23 chemicals that have been previously reported to affect aromatase activity in vitro. We confirmed that 17 of 23 test chemicals had inhibitory or inducible effects, although the specific effects of some were different than previously reported. In conclusion, we have developed a simple, sensitive, and nonradioactive assay that can be used for large-scale screening of compounds that can disrupt endocrine function by influencing aromatase activity.
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PMID:A novel nonradioactive method for measuring aromatase activity using a human ovarian granulosa-like tumor cell line and an estrone ELISA. 1545 20

Carcinogenesis in the breast is a hormonally dependent process. Evidence implicating estrogen as a key breast carcinogen comes from various lines of investigation. Traditional epidemiologic studies demonstrate associations between estrogen exposure, both exogenous and endogenous, and increased breast cancer risk. Ongoing genetic epidemiologic studies also show associations between specific polymorphisms in estrogen-metabolizing genes and risk, albeit inconsistently. The application of these findings to the treatment and, more recently, the prevention of breast cancer has led to the development of agents that either (1) inhibit estrogen action at the estrogen receptor (selective estrogen receptor modulators (SERMs]); or (2) inhibit estrogen-synthesizing enzymes, thereby abrogating synthesis of this hormone (aromatase inhibitors). Large phase III trials have evaluated the ability of such agents to reduce the incidence of breast cancer in women at increased risk of the disease. The National Surgical Adjuvant Breast and Bowel Project (NSABP) P-1: Breast Cancer Prevention Trial (BCPT) demonstrated the superiority of the SERM tamoxifen to placebo in reducing breast cancer risk, leading to the Food and Drug Administration approval of tamoxifen for risk reduction. The implementation of tamoxifen for this indication has not become widespread in clinical practice, however, for a variety of reasons that we discuss. Results from the NSABP Study of Tamoxifen and Raloxifene, which compares the risk-reducing efficacy as well as toxicity of these two SERMs in a similar high-risk population, will be available in the near future. Based on promising data involving reduction of contralateral breast cancer risk in adjuvant studies, several aromatase inhibitors, including letrozole, anastrozole, and exemestane, are being incorporated into trials evaluating their efficacy as preventive agents in women at increased risk.
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PMID:Prevention of hormone-related cancers: breast cancer. 1599 63

Considerable data implicate estrogens in breast cancer carcinogenesis and progression. In the postmenopausal woman, estrogens are produced in breast tissues and many other sites throughout the body when androgen precursors are converted into estrogens via the enzyme aromatase. Inhibition of this enzyme with aromatase inhibitors (AIs) has demonstrated reductions in systemic as well as intratumoral estrogens. These drugs have now been utilized in large phase 3 randomized trials and have led to greater improved clinical benefit than the "gold standard," tamoxifen. Questions remain about the long-term side effects and safety profile of AIs. They are associated with increasing incidence of osteoporosis and bone fractures. Nevertheless, AIs add to our armamentarium for therapy and possible prevention of breast cancer.
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PMID:Aromatase inhibitors: rationale and use in breast cancer. 1566 May 4

Cyclooxygenases (Cox) are prostaglandin synthetase enzymes which play a key role in mammary carcinogenesis. Several connections were demonstrated between Cox and a few oncogenes (v-src, v-Ha-ras, HER-2\neu, Wnt, p53 mutated), alimentary products (PUFAs), transcription factors (c-jun and c-fos), proapoptotic proteins [Bax et Bcl-x(L)] or antiapoptotic (Bcl-2), CYP19 aromatase gene, NFkappaB receptor (RANKL), angiogenesis (via VEGF, TXA2, oxid nitric synthetase, alphaVbeta3 integrin receptor), peroxisome gamma proliferator receptor (PPARgamma) and its ligand PGJ2 and with antitubuline chemotherapy drugs. No correlation of Cox2 expression with hormonal receptors was shown. In epidemiologic studies there is evidence of breast cancer risk reduction for women who take AINS for a lon time. Alimentary factors like resveratrol or insaturated fat acid reduce Cox2 expression in animal and could be investigated in human studies. Clinical trials are planed with the anti Cox2 celecoxib for breast cancer prevention, in adjuvant setting, in metastatic situation combined with exemestane or antitubulin drugs or in neoadjuvant therapy.
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PMID:[Cyclooxygenase 2 and breast cancer. From biological concepts to clinical trials]. 1589 33

Aromatase transgenic mice exhibit hyperplastic and dysplastic changes, attesting to the importance of local estrogen in breast carcinogenesis. These mice also show increased levels of the estrogen receptor alpha and beta (ERalpha, ERbeta) suggesting that this receptor may play an important role in the initiation of estrogen-mediated mammary hyperplasia observed in these mice. To address the specific role of ERalpha in the mammary development and in the induction of estrogen-mediated hyperplasia in aromatase transgenic mice, we have generated MMTV-aromatase x ERalpha knockout cross (referred as aromatase/ERKO). Even though ERbeta is expressed in aromatase/ERKO mice, lack of ERalpha leads to impaired mammary growth in these mice. The data suggest that ERalpha plays an important role in the mammary gland development as well as in the induction of mammary hyperplasia in aromatase transgenic mice. Lack of ERalpha expression in the aromatase/ERKO mice resulted in a decrease in the expression of Cyclin D1, PCNA and TGFbeta relative to the aromatase parental strain. The studies involving aromatase/ERKO mice show that lack of ERalpha results in impaired mammary development even in the presence of continuous tissue estrogen, suggesting estrogen/ERalpha-mediated actions are critical for mammary development and carcinogenesis.
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PMID:Estrogen receptor alpha is required for mammary development and the induction of mammary hyperplasia and epigenetic alterations in the aromatase transgenic mice. 1595 96

Flavonoids are present in fruits, vegetables and beverages derived from plants (tea, red wine), and in many dietary supplements or herbal remedies including Ginkgo Biloba, Soy Isoflavones, and Milk Thistle. Flavonoids have been described as health-promoting, disease-preventing dietary supplements, and have activity as cancer preventive agents. Additionally, they are extremely safe and associated with low toxicity, making them excellent candidates for chemopreventive agents. The cancer protective effects of flavonoids have been attributed to a wide variety of mechanisms, including modulating enzyme activities resulting in the decreased carcinogenicity of xenobiotics. This review focuses on the flavonoid effects on cytochrome P450 (CYP) enzymes involved in the activation of procarcinogens and phase II enzymes, largely responsible for the detoxification of carcinogens. A number of naturally occurring flavonoids have been shown to modulate the CYP450 system, including the induction of specific CYP isozymes, and the activation or inhibition of these enzymes. Some flavonoids alter CYPs through binding to the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, acting as either AhR agonists or antagonists. Inhibition of CYP enzymes, including CYP 1A1, 1A2, 2E1 and 3A4 by competitive or mechanism-based mechanisms also occurs. Flavones (chrysin, baicalein, and galangin), flavanones (naringenin) and isoflavones (genistein, biochanin A) inhibit the activity of aromatase (CYP19), thus decreasing estrogen biosynthesis and producing antiestrogenic effects, important in breast and prostate cancers. Activation of phase II detoxifying enzymes, such as UDP-glucuronyl transferase, glutathione S-transferase, and quinone reductase by flavonoids results in the detoxification of carcinogens and represents one mechanism of their anticarcinogenic effects. A number of flavonoids including fisetin, galangin, quercetin, kaempferol, and genistein represent potent non-competitive inhibitors of sulfotransferase 1A1 (or P-PST); this may represent an important mechanism for the chemoprevention of sulfation-induced carcinogenesis. Importantly, the effects of flavonoids on enzymes are generally dependent on the concentrations of flavonoids present, and the different flavonoids ingested. Due to the low oral bioavailability of many flavonoids, the concentrations achieved in vivo following dietary administration tend to be low, and may not reflect the concentrations tested under in vitro conditions; however, this may not be true following the ingestion of herbal preparations when much higher plasma concentrations may be obtained. Effects will also vary with the tissue distribution of enzymes, and with the species used in testing since differences between species in enzyme activities also can be substantial. Additionally, in humans, marked interindividual variability in drug-metabolizing enzymes occurs as a result of genetic and environmental factors. This variability in xenobiotic metabolizing enzymes and the effect of flavonoid ingestion on enzyme expression and activity can contribute to the varying susceptibility different individuals have to diseases such as cancer. As well, flavonoids may also interact with chemotherapeutic drugs used in cancer treatment through the induction or inhibition of their metabolism.
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PMID:Dietary flavonoids: effects on xenobiotic and carcinogen metabolism. 1628 44

Epidemiologic studies have implicated estrogenic exposure as well as human papilloma virus (HPV) infection in cervical carcinogenesis, and some studies have suggested that estrogen and HPV may play synergistic roles in cervical tumorigenesis. In this study, we report a novel finding that approximately 35% of cervical carcinomas tested (n = 19) express aromatase, the enzyme responsible for converting androgen to estrogen, the rate-limiting and final step in estrogen biosynthesis. On the other hand, no aromatase expression was detected in precancerous (n = 42) or normal cervical (n = 17) tissue samples. Increased aromatase was associated with increases in estrogen receptors (ER-alpha and ER-beta) and a decrease in progesterone receptor levels, suggesting that in situ estrogen signaling via ER may be involved in tumor growth. Stable overexpression of aromatase in HPV+ cervical cancer cells resulted in increased cellular proliferation, anchorage-independent growth, and ER expression and activity. In contrast, little change in ER was observed in HPV- cells. Steroid hormone receptor expression observed in vitro paralleled that seen in cervical carcinomas expressing aromatase. Aromatase overexpression also induced the expression of cyclin D1, proliferating cell nuclear antigen, and the HPV oncogenes, E6 and E7. Furthermore, the data underscores the importance of steroid receptor (estrogen and progesterone receptors) regulation in cervical carcinogenesis. To our knowledge, this is the first report demonstrating the induction of aromatase expression in cervical carcinomas, and opens the possibility that aromatase inhibitors may be potential therapeutic agents in cervical carcinomas expressing aromatase.
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PMID:Induction of aromatase expression in cervical carcinomas: effects of endogenous estrogen on cervical cancer cell proliferation. 1632 67

Hormonal therapy and chemotherapy play a major role in the management of advanced or recurrent endometrial cancer. Progesterone therapy obtains overall response rates ranging from 11% to 25% in patients with endometrioid-type tumours, and oral medroxyprogesterone acetate 200mg daily appears to be a reasonable therapeutic option for those lesions that are well differentiated and/or have a high progesterone receptor (PgR) content. However, the activity of progestins is often compromised by the down-regulation of PgR within the target tissues, and therefore therapeutic strategies designed to enhance PgR expression are warranted. Little data are currently available about the new aromatase inhibitors and selective estrogen receptor modulators. As for chemotherapy, the combination of doxorubicin [DOX]+cisplatin [CDDP] achieves overall response rates ranging from 34% to 60%, and the addition of paclitaxel (TAX) seems to improve response rates, progression-free survival and overall survival, but to worsen toxicity profile. A phase III study is currently comparing TAX+DOX+CDDP versus the less toxic combination of TAX+carboplatin. Chemotherapy is active against both endometrioid-type carcinoma and uterine serous papillary carcinoma. However, this latter endometrial malignancy is less chemosensitive than the histologically similar high-grade serous ovarian carcinoma. Interesting fields of research are represented by investigational agents directed against specific intracellular signal transduction pathways involved in the proliferation, invasiveness and metastatic spread of endometrial cancer. Mammalian target of the rapamycin (mTOR) inhibitors, epidermal growth factor receptor inhibitors (gefitinib, erlotinib, lapatinib, the monoclonal antibody cetuximab), imatinib, the monoclonal antibody trastuzumab, and the Clostridium perfrigens enterotoxin are currently under evaluation as molecularly targeted therapies for endometrial cancer. Further investigations addressed to better understand the signal transduction pathways that are disregulated in endometrial carcinogenesis could identify novel biological targets suitable for tailored therapies.
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PMID:Old and new perspectives in the pharmacological treatment of advanced or recurrent endometrial cancer: Hormonal therapy, chemotherapy and molecularly targeted therapies. 1643 30


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