Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0007097 (carcinoma)
 152,788 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Amphiregulin is a heparin-binding epidermal growth factor (EGF)-related peptide that binds to the EGF receptor (EGF-R) with high affinity. In this study, we report a role for amphiregulin in androgen-stimulated regulation of prostate cancer cell growth. Androgen is known to enhance EGF-R expression in the androgen-sensitive LNCaP human prostate carcinoma cell line, and it has been suggested that androgenic stimuli may regulate proliferation, in part, through autocrine mechanisms involving the EGF-R. In this study, we demonstrate that LNCaP cells express amphiregulin mRNA and peptide and that this expression is elevated by androgenic stimulation. We also show that ligand-dependent EGF-R stimulation induces amphiregulin expression and that androgenic effects on amphiregulin synthesis are mediated through this EGF-R pathway. Parallel studies using the estrogen-responsive breast carcinoma cell line, MCF-7, suggest that regulation of amphiregulin by estrogen may also be mediated via an EGF-R pathway. In addition, heparin treatment of LNCaP cells inhibits androgen-stimulated cell growth further suggesting that amphiregulin can mediate androgen-stimulated LNCaP proliferation. Together, these results implicate an androgen-regulated autocrine loop composed of amphiregulin and its receptor in prostate cancer cell growth and suggest that the mechanism of steroid hormone regulation of amphiregulin synthesis may occur through androgen upregulation of the EGF-R and subsequent receptor-dependent pathways.
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PMID:Epidermal growth factor receptor-dependent stimulation of amphiregulin expression in androgen-stimulated human prostate cancer cells. 804 25

We investigated the effects of dihydrotestosterone (DHT), hydrocortisone (HC), basic fibroblast growth factor (bFGF), and opioid peptides on the growth of cells from the androgen-responsive Shionogi mouse mammary carcinoma (SC115) in primary culture. Androgen-responsive SC115 tumor cells were stimulated to grow in response to DHT, HC, and bFGF in a dose-responsive manner in both serum-containing and serum-free media. Moreover, anti-bFGF antibody had a marked inhibitory effect on DHT- and bFGF-induced growth. Three opioid agonists, beta-endorphin (beta-EP), cyclazocine, and morphine sulfate, markedly inhibited SC115 tumor cell growth at concentrations ranging from 10(-11) to 10(-7) M in serum-containing medium with or without DHT, HC, or bFGF, with the greatest inhibition occurring in medium with DHT. In serum-free medium, beta-EP had no inhibitory effects on cell growth. However, beta-EP at concentrations of 10(-9) M or greater significantly inhibited cell growth in serum-free medium containing DHT, HC, or bFGF, with the greatest inhibition again occurring in medium with DHT. Naloxone (10(-8) and 10(-6) M), an opioid receptor antagonist, blocked the inhibitory effects of beta-EP and morphine sulfate. These results suggest that SC115 tumor cells in primary culture are stimulated to grow in a dose-responsive manner by DHT, HC, or bFGF in both serum-containing and serum-free media. It appears that bFGF may mediate, at least partially, DHT-stimulated cell growth. In addition, the opioid peptide system may be involved in regulating endocrine control of growth of the androgen-responsive SC115 carcinoma. The dose-responsive inhibitory effects of opioids and their reversal by naloxone suggest that these effects may be mediated by opioid receptors.
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PMID:Effects of steroid hormones and opioid peptides on the growth of androgen-responsive Shionogi carcinoma (SC115) cells in primary culture. 836 18

In response to androgen stimuli, SC-3 cells cloned from mouse mammary carcinoma (Shionogi carcinoma 115) secrete heparin-binding growth factor, which is able to bind to fibroblast growth factor (FGF) receptor, ultimately resulting in SC-3 cell proliferation. A role for glycosaminoglycan in the process of this androgen-induced autocrine loop was examined. When quiescent SC-3 cells were stimulated with testosterone, enhanced DNA synthesis was demonstrated even at the early phase (12-24 h) of stimulation. During this early period, autocrine growth-promoting activity was found to be associated with cell surface and extracellular matrix, but not to be present in the conditioned medium. This bound form of growth-promoting activity was able to be extracted with 2 M NaCl (pH 7.5) and absorbed onto a heparin-Sepharose affinity column, from which it was eluted at a concentration of 1.1-1.3 M NaCl. Extracted growth factor, whose activity was partially blocked by anti-basic FGF antibody, up-regulated the expression of FGF receptor-1 mRNA. These characteristics were similar to those of a soluble form of SC-3-derived growth factor previously reported from our laboratory. Androgen-induced enhancement of DNA synthesis was inhibited by simultaneous treatment of SC-3 cells with 10 mIU/ml heparitinase or 25 mM sodium chlorate (an inhibitor of phosphoadenosine sulfate synthesis). However, chlorate treatment did not affect the synthesis and distribution of androgen-induced growth factor, suggesting that the response of chlorate-treated cells to this growth factor was impaired. These results indicate that heparan sulfate has important roles in concentrating androgen-induced heparin-binding growth factor on or very close to the cell surface and in potentiating its bioactivity.
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PMID:A role for heparan sulfate in androgen-induced deoxyribonucleic acid synthesis of mouse mammary carcinoma (Shionogi carcinoma 115)-derived SC-3 cells. 844 Jan 81

Epidermal growth factor (EGF) and transforming growth factor-alpha (TGF alpha) are two closely related peptides that interact with cell-surface epidermal growth factor receptors (EGFR) to induce receptor tyrosine phosphorylation and activation of intracellular signal-transduction pathways. EGF appears to be the predominant EGF-related growth factor in the normal prostate and in benign prostatic hyperplasia (BPH). Evidence indicates that EGF and TGF alpha are important for maintainence of the structural and functional integrity of the benign prostatic epithelium. The EGF-related peptides are primarily localized to the secretory epithelium of the benign prostate, and their production and secretion is augmented by the presence of circulating androgens. EGFR are located in the basal/neuroendocrine (NE) compartment of the benign prostate and exhibit relatively androgen-independent expression. The EGF-related peptides and EGFR are also present in neoplastic prostatic tissues. There is currently no direct evidence to implicate EGFR activation in the pathogenesis of BPH. However, the EGF-related peptides appear to play a functional role in the growth of prostatic carcinoma cells, with TGF alpha being the predominant growth factor. Numerous investigators have demonstrated the functional significance of a TGF alpha/EGFR-mediated autocrine growth pathway in cultured prostatic carcinoma cells. Studies of cultured prostate cancer cells, but not normal epithelial cells, demonstrate constitutive activation of EGFR. Androgen-independent cancer cells exhibit more EGFR expression and phosphorylation than do androgen-responsive prostate cancer cells. Most studies indicate that EGFR do not play a functional role in androgen-stimulated growth of prostate cancer cells. Several studies have correlated EGFR expression with increased nuclear size and tumor dedifferentiation. Future studies should focus on determining both the prognostic significance of EGFR expression and whether manipulation of EGFR-mediated growth can be exploited for therapeutic benefit in human prostate cancer.
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PMID:Epidermal growth factor-related peptides and the epidermal growth factor receptor in normal and malignant prostate. 858 Oct

Androgens play a key role in prostate structure and function, leading to the hypothesis that effects of the hormone are an important component in the development of prostatic disease. Differences in serum testosterone levels and 5alpha-reductase activities between ethnic and racial groups have been implicated in the variable incidence of prostate cancer among certain populations. Androgen receptors transduce the steroid signal within cells, but attempts to correlate differences in receptor levels with prostatic disease have been unsuccessful. However, molecular studies of androgen receptor gene structure have recently provided new insights toward defining a genetic basis for the pathology associated with three diseases--spinal bulbar muscular atrophy, breast carcinoma, and prostate cancer--affecting middle-aged and older men. In summary, epidemiologic data on androgen biosynthesis, metabolism, and action of androgens and molecular genetic analysis of gene structure have led to a new understanding of the interrelationships between environmental and genetic factors that may impact on the incidence of certain pathologic conditions in men.
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PMID:Provocative aspects of androgen genetics. 863 Feb 38

Thanks to earlier detection of clinically significant prostatic adenocarcinoma by measurement of serum prostate-specific antigen (PSA) levels, increasing numbers of patients are undergoing radical prostatectomy. However, the curative potential of this procedure is seriously limited by clinical understaging, which results in positive surgical margins and a marked increase in disease progression. In a multicenter study, histopathologic evaluation of radical prostatectomy specimens showed that presurgical androgen deprivation with leuprolide plus flutamide reduced the incidence of surgical margin involvement by 62%. In patients who received androgen deprivation therapy, characteristic and recognizable histopathologic changes in nontumor glands included atrophy, basal cell prominence, vacuolated luminal cell layers, and squamous and transitional cell metaplasia. Androgen deprivation markedly reduced the incidence of prostatic intraepithelial neoplasia (PIN) to 35%. The effects of androgen deprivation on prostatic carcinoma included smaller tumor glands, pyknosis and empty glandular spaces, and vacuolization and degeneration of tumor cells with an inflammatory response. Similar but less pronounced changes with no decrease in PIN were observed in finasteride-treated patients. It is important for pathologists to be aware of these histological changes and process tissue appropriately, because the changes affect the recognition and histological grading of tumors in radical prostatectomy specimens.
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PMID:Histopathological effects of androgen deprivation in prostatic cancer. 872 88

Androgen deprivation is the most effective therapy for patients with advanced prostatic carcinoma. The lack of androgen stimulation on these cells causes them to become apoptotic. Although therapeutic efficacy of initial androgen deprivation in prostate cancer is high, the emergence of androgen-independent cancer is inevitable. Withdrawal of the antiandrogen flutamide elicits surprising activity in these cancers. In numerous studies the response rates cell line harbors a mutation in codon 877 of the androgen receptor. The mutant receptor loses androgen specificity and is activated by various steroids as well as flutamide. Identical and similar mutations have now been isolated from human prostate cancer tissue. The discovery of the mutated androgen receptor sheds light on the emergence of androgen-independent cancer and should facilitate the development of more efficacious therapies.
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PMID:The mutated androgen receptor and its implications for the treatment of metastatic carcinoma of the prostate. 872 95

Androgen suppression, using gonadotrophin-releasing hormone analogues (leuprorelin), is being developed as an effective treatment of advanced prostate carcinoma. Treatment with leuprorelin acetate 1-month depot is already well established all over the world. In order to increase patients' acceptability of this treatment, by reducing frequency of administration, a 3-month depot formulation has been developed in Takeda's research laboratories. A single-shot pharmacokinetic study was conducted to confirm efficacy in terms of hormone suppression and safety of the 3-month depot formulation. Thereafter, a parallel-group, open-labelled, randomized trial was performed to compare clinical efficacy and safety profiles of the 1- and 3-month depot formulations. Patients with a histologically and/or cytologically confirmed advanced prostate carcinoma, without prior hormonal or surgical androgen deprivation, are included. According to 1:2 randomization, patients are treated with either the 1- or 3-month depot for 9 months. To prevent initial flare-up, a concomitant antiandrogen therapy might be administered within 2 weeks prior to first injection and continued for up to 3 weeks. The clinical efficacy of the formulations is assessed by both objective response, EORTC and NPCTG response criteria, and subjective response by using WHO performance status. In addition, the level of prostate-specific antigen is determined every 3 months. The efficacy of the two formulations is also evaluated by determination of serum testosterone, dihydrotestosterone, luteinizing hormone and follicle stimulating hormone. To date, 106 patients have been treated with the 3-month depot and 53 patients with the 1-month depot. Preliminary evaluation shows a satisfying level of testosterone suppression with both the 3- and 1-month depot formulations. Therapeutic equivalence was assumed. The 3-month depot is tolerated as well as the 1-month depot.
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PMID:Clinical study results of the new formulation leuprorelin acetate three-month depot for the treatment of advanced prostate carcinoma. 877 13

In an open, prospective clinical trial enrolling 205 patients, efficacy and safety of the gonadotropin-releasing hormone agonist leuprorelin acetate depot (LAD) in the treatment of patients with advanced prostatic carcinoma were assessed. 3.75 mg of the LAD formulation was injected subcutaneously in monthly intervals. The primary objective of this study was to evaluate the efficacy of the analogue in producing and maintaining castration levels of testosterone over a > 3-year follow-up period and to determine its safety profile. Median pretreatment serum testosterone levels fell from 350 to 21 ng/dl after 4 weeks and 20 ng/dl after 45 months. The long-term clinical efficacy of the LAD formulation can be expressed by best treatment response over time. These respective figures read as follows: 10.7% complete response; 49.8% partial response; 34.1% no change; 1.5% progression, and 3.9% no data available. The median time to progression was 12 (15 +/- 11) months. Median survival time calculated by Kaplan-Meier exceeded 42.5 months for patients on monotherapy and 30.9 months for those on combination therapy. Hot flushes which were related to androgen deprivation were the most common side effects. Patients and treating physicians judged tolerability of LAD in more than 90% as good. Androgen deprivation remains the mainstay of hormone-dependent advanced carcinoma of the prostate. Up to now, surgical castration has been considered the standard method. LAD is an advantage in the endocrine treatment of advanced prostatic carcinoma and is a good alternative to castration.
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PMID:Efficacy and safety of leuprorelin acetate depot for prostate cancer. The German Leuprorelin Study Group. 877 14

When the human prostate cancer cell line, LNCaP 104-S, the growth of which is stimulated by physiological levels of androgen, is cultured in androgen-depleted medium for > 100 passages, the cells, now called LNCaP 104-R2, are proliferatively repressed by low concentrations of androgens. LNCaP 104-R2 cells formed tumors in castrated male athymic nude mice. Testosterone propionate (TP) treatment prevented LNCaP 104-R2 tumor growth and caused regression of established tumors in these mice. Such a tumor-suppressive effect was not observed with tumors derived from LNCaP 104-S cells or androgen receptor-negative human prostate cancer PC-3 cells. 5 alpha-Dihydrotestosterone, but not 5 beta-dihydrotestosterone, 17 beta-estradiol, or medroxyprogesterone acetate, also inhibited LNCaP 104-R2 tumor growth. Removal of TP or implantation of finasteride, a 5 alpha-reductase inhibitor, in nude mice bearing TP implants resulted in the regrowth of LNCaP 104-R2 tumors. Within 1 week after TP implantation, LNCaP 104-R2 tumors exhibited massive necrosis with severe hemorrhage. Three weeks later, these tumors showed fibrosis with infiltration of chronic inflammatory cells and scattered carcinoma cells exhibiting degeneration. TP treatment of mice with LNCaP 104-R2 tumors reduced tumor androgen receptor and c-myc mRNA levels but increased prostate-specific antigen in serum- and prostate-specific antigen mRNA in tumors. Although androgen ablation has been the standard treatment for metastatic prostate cancer for > 50 years, our study shows that androgen supplementation therapy may be beneficial for treatment of certain types of human prostate cancer and that the use of 5 alpha-reductase inhibitors, such as finasteride or anti-androgens, in the general treatment of metastatic prostate cancer may require careful assessment.
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PMID:Human prostate tumor growth in athymic mice: inhibition by androgens and stimulation by finasteride. 887 18


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