Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0376358 (prostate cancer)
 59,338 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Forty-six patients with prostatic carcinoma received the gonadotropin releasing hormone agonistic analogue (GnRH-A) Buserelin at doses ranging from 0.05 to 1.5 mg subcutaneously and/or 0.4 to 1.2 mg intranasally (i.n.) daily for 12-120 weeks. An increase in plasma testosterone (T) was seen in 19% of patients on day 7 of therapy; with continuation of treatment plasma T as well as DHT and E2 levels fell by more than 50% within 2-4 weeks in those patients receiving greater than or equal to 50 micrograms s.c. and/or greater than or equal to 1 mg in daily dose. Persistently low plasma T levels (less than 1 ng/ml) were reached in 60% of patients receiving 50 micrograms s.c. in 89% of those treated with 1.2 mg i.n. and in 100% of patients who received initially 1.5 mg s.c. X 7 days followed by 1.2 mg i.n. daily. The above data indicate the importance of dose and route of administration in achieving significant suppression of plasma sex steroids in patients with prostate cancer in whom Buserelin can be used as an alternative to castration or estrogens.
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PMID:Suppression of testicular steroidogenesis by the GnRH agonistic analogue Buserelin (HOE-766) in patients with prostatic cancer: studies in relation to dose and route of administration. 641 94

At least 80 per cent of prostatic tumors exhibit some degree of hormone responsiveness. The preferred method of hormonal alteration has yet to be determined because new agents are currently undergoing clinical trials. The compounds tested have included cyproterone acetate, a progestational agent; flutamide, an antiandrogen that blocks the DHT-receptor complex in the tumor cell; and aminoglutethimide, which inhibits adrenal steroid production and, therefore, might further lower the level of circulating androgen following bilateral orchiectomy. The introduction of potent, synthetic analogues of gonadotropin-releasing hormone (GnRH) has provided another method of reducing the level of circulating androgen. A recent report on the efficacy of one of these analogues--leuprolide--in men with newly diagnosed metastatic prostatic cancer has revealed an initial response rate of 76 per cent (4% complete remissions, 32% partial remissions, and 40% stable) using National Prostatic Cancer Project criteria.
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PMID:Newer methods of hormonal therapy for prostate cancer. 643 34

High pressure liquid chromatography (HPLC) was used to determine 3H-estramustine (estradiol-17 beta 3N-bis-[2-chlorethyl] carbamate), 3H-17 beta-hydroxy-5 alpha-androstan-3-one (3H-dihydrotestosterone or 3H-DHT), 3H-estradiol-17 beta (3H-E2) and 3H-3 beta-hydroxy-5-pregnen-20-one (3H-pregnenolone) binding in 50(2) microliter of cytosol utilizing a column which separates proteins in the molecular weight range of 2,000 to 70,000 daltons. The rat prostate contains a protein in considerable concentration and with the highest affinity for estramustine (375,000 dpm 3H-estramustine per mg. cytosol protein) among the substances tested. Operationally, we have named this protein "estramustine binding protein" (EBP), though it is very likely similar to other previously described prostatic proteins (e.g., alpha-protein, prostatein, prostatic binding protein). The sensitivity of the HPLC method disclosed EBP-like proteins, but in much lesser concentrations, in some of the other tissues tested. The concentration of these proteins in the human and baboon prostates was much lower (average for the baboon cranial lobe 4800 dpm/mg cytosol protein, with a somewhat higher value for the caudal lobe) than that in the rat gland. The amount of the EBP-like protein was higher in prostatic cancer than in that of benign prostatic hypertrophy (BPH) (range 9350--25,900 vs. 2200--18,900 dpm/mg cytosol protein). In the human, the highest value was found in one normal prostate tested (106,000 dpm/mg cytosol protein).
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PMID:Estramustine binding in rat, baboon and human prostate measured by high pressure liquid chromatography. 725 14

5 alpha-Reductase inhibitors are a new class of substances with very specific effects on type I and type II 5 alpha R which may be of use in the treatment of skin disease, such as male pattern baldness, male acne and hirsutism, as well as prostatic hyperplasia and prostate cancer. At least two types of 5 alpha R inhibitors with a different pH optimum have been described. cDNA encoding for both the type I and the type II enzyme has been cloned. Most of the orally effective 5 alpha R inhibitors belong to the class of 4-azasteroids. The radical substituted in the 17 position of the steroid ring seems to be related to species specific variations and to the types of 5 alpha R enzymes in different species and organ systems. 5 alpha R inhibitors lead to a decrease of plasma DHT by about 65% while there is a slight rise in plasma testosterone. The decrease of tissue DHT in the ventral prostate of the intact rat, the dog and in humans is more pronounced and amounts to about 85%. There is a reciprocal rise of tissue T in these systems. The application of an inhibitor of 5 alpha R type II leads to a shrinkage of BPH in men by about 30%. In the rat a similar shrinkage accompanied by a significant decrease of total organ DNA occurs. This decrease, however, is not as pronounced as can be achieved with castration.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:5 alpha-reductase inhibitors and prostatic disease. 752 99

The crucial role played by androgens in the growth of prostatic carcinoma is now well established. However, the mechanisms of this proliferative action are still poorly understood. Experiments have been performed to clarify: (1) the metabolism of androgens in prostatic tumor cells; and (2) the role played by locally produced growth factors in the autocrine regulation of prostatic tumor cell proliferation and the possible regulation exerted by testosterone (T) on the activity of these factors. These studies have been performed by utilizing the human androgen-responsive prostatic cancer LNCaP cell line. (1) By incubating LNCaP cells with different 14C-labeled androgenic precursors, it has been shown that all the major key enzymes involved in the metabolism of androgens (5 alpha-reductase, 17 beta-hydroxysteroid-oxidoreductase, 3 alpha- and 3 beta-hydroxysteroid-oxidoreductases) are present and active in these cells. In particular, the 5 alpha-reductase, which converts T and delta 4 to DHT and 5 alpha-A respectively, seems to be more active when delta 4 is the substrate, suggesting a preference for this precursor. (2) The hypothesis that LNCaP cells might produce LHRH (or a LHRH-like peptide) has been verified by RT-PCR, performed in the presence of a pair of specific oligonucleotide primers. A cDNA band of the expected size (228 bp), which specifically hybridized with a 32P-labeled LHRH oligonucleotide probe, has been obtained in LNCaP cells. To clarify the possible role played by this factor in the regulation of tumor growth, LNCaP cells, cultured in steroid-free conditions, have been treated with a LHRH antagonist; the treatment resulted in a significant increase of cell proliferation. Taken together, these data indicate that a LHRH (or LHRH-like) growth modulatory system is expressed in LNCaP cells and plays an inhibitory role in the regulation of tumor cell proliferation. This system seems to be regulated in a negative way by steroids. Growth factors endowed with stimulatory activity, such as EGF and TGF alpha, have also been shown to be produced by LNCaP cells. The present studies show that the immunoprecipitation of the EGF receptor with a specific monoclonal antibody (Ab225) reveals a protein band of the expected size (170 kDa) which is phosphorylated even in basal conditions. Moreover, the treatment of LNCaP cells, cultured in serum-free conditions, either with a monoclonal antibody against the EGF receptor, or with immunoneutralizing antibodies against EGF and TGF alpha, results in a significant decrease of cell proliferation.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Growth of the androgen-dependent tumor of the prostate: role of androgens and of locally expressed growth modulatory factors. 762 87

Progression to hormone-refractory disease is a common outcome of human prostate cancer. In this study, we have investigated the basis of androgen insensitivity in the human prostate cancer cell line, PC-3, which was derived from a bone metastasis of a hormone-refractory prostate cancer. PC-3 cells with virtually undetectable (PC-3AR-) or low (PC-3AR+) levels of androgen receptor (AR) RNA expression were examined. RNase protection assays demonstrated that the level of AR RNA in PC-3AR+ cells was similar to that in a normal androgen-responsive genital skin fibroblast cell strain. Quantitative immunocytochemical staining of AR in PC-3AR+ cells using antibodies directed against the amino and carboxyl termini of the receptor revealed staining in 30% of cells with either antibody. Furthermore, the level of AR staining in PC-3AR+ cells was higher than in the androgen-responsive breast cancer cell lines ZR-75-1, T47-D, and MCF-7. Despite the expression of AR RNA and protein, PC-3AR+ cell proliferation was unaffected by the presence of 0.1-10 nM mibolerone. Scatchard analysis demonstrated a complete absence of specific [3H]dihydrotestosterone ([3H]DHT) binding to PC-3AR+ cytosolic extracts, which could not be explained by structural alterations in the AR gene. The sizes of individual AR exons amplified from genomic DNA derived from PC-3AR+ cells were identical to those amplified from normal human cells. Furthermore, sequence analysis did not reveal a mutation in the DNA- or hormone-binding domains of the AR gene in PC-3AR+ cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Evidence for a novel mechanism of androgen resistance in the human prostate cancer cell line, PC-3. 779 9

We have prepared 11 beta-fluoro-5 alpha-dihydrotestosterone (11 beta-F-DHT, 1) and 11 beta-fluoro-19-nor-5 alpha-dihydrotestosterone (11 beta-F-19-nor-DHT, 2) in order to investigate the properties of these new androgens labeled with fluorine-18 as potential androgen receptor (AR)-based imaging agents for prostate cancer. These compounds were synthesized in 6 steps from hydrocortisone and in 13 steps from 1,4-androstadiene-3,11,17-trione, respectively. Relative binding affinities (RBA) of 11 beta-F-DHT and 11 beta-F-19-nor-DHT to AR are 53.1 and 75.3 (R1881 = 100), respectively, the latter being the highest reported among fluorine-substituted androgens. The fluorination step, which involves addition of halogen fluoride across the 9(11)-double bond, followed by reductive dehalogenation at the 9 alpha-position has been adapted to introduce a fluorine-18-label at the 11 beta-position of DHT and 19-nor-DHT. The two high-affinity F-18-labeled ligands [18F]-1 and [18F]-2 were evaluated in vivo, in tissue distribution studies using diethylstilbestrol-pretreated mature male rats. 11 beta-F-DHT shows high prostate uptake and selective prostate to blood and prostate to muscle uptake ratios, the latter two ratios increasing from 5 and 8 at 1 h to 12 and 19 at 4 h postinjection. Moreover, this compound has low uptake in bone, displaying the lowest in vivo defluorination among all androgens labeled with fluorine-18 tested so far. The in vivo properties of 11 beta-F-DHT in rats are thus favorable for imaging of prostate cancer. On the other hand, 11 beta-F-19-nor-DHT shows low prostate uptake with low selectivity and high uptake in liver, kidney, and bladder. Even though this ligand has the highest RBA and undergoes little metabolic defluorination, it appears to suffer from rapid metabolism in vivo. Therefore, it is apparent that the biodistribution properties of androgens are affected by their structure and metabolism as well as by their RBA.
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PMID:Synthesis of 11 beta-[18F]fluoro-5 alpha-dihydrotestosterone and 11 beta-[18F]fluoro-19-nor-5 alpha-dihydrotestosterone: preparation via halofluorination-reduction, receptor binding, and tissue distribution. 787 47

The concept of differentiation of prostate cancer in terms of morphonuclear characteristics and population dynamics was investigated on the PC-3 and DU145 cell lines. A software based on the concept of Voronoi paving was set up in order to characterize the structure of these cell lines growing in vitro on histological slides. The morphonuclear characteristics were assessed by means of the digital cell image analyses of Feulgen-stained nuclei. The in vitro "morphonuclear" and "pseudo-tissular" differentiations of the PC-3 and DU145 cells were described in terms of the use of various culture media, i.e., media supplemented with either 10% (F10 medium) or 1% (F1 medium) fetal calf serum and with (or without) platelet-derived growth factor and dihydrotestosterone (PA10 and PA1 media). The present data reveal that the PC-3 cell line would be more hormone-sensitive than the DU145 one. Indeed, decreasing the FCS concentration in the culture medium while adding DHT and PDGF led to marked modifications to the morphonuclear characteristics of the PC-3 cells, but not to the DU145 cells. These modifications corresponded to an increase in nuclear size occurring concomitantly with chromatin decondensation. In the same way, spectacular modifications in terms of medium-induced pseudo-tissular differentiation were observed in the PC-3 cell line, but not in the DU145 one. Such modifications corresponded to an increase in clone size related to an increase in the mean distances between neighboring cell nuclei in a given clone. Thus, according to the criteria defined in this study, the PC-3 cell line would seem to maintain a higher degree of differentiation than the DU145 cell line.
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PMID:Influence of culture media on the morphological differentiation of the PC-3 and DU145 prostatic neoplastic cell lines. 814 67

The literature contains many accounts of studies in which tumour growth has been accelerated by administration of a particular mitogen and the response then inhibited by co-administration of the corresponding antagonist. Much effort has been focused on the development of cytokine or growth factor antagonists. Like most other cancer therapies, biological therapies will undoubtedly have undesirable toxicities because the proteins they target may not be unique to malignant cells. We reviewed the clinical and therapeutic potential of growth factor agonists and antagonists in some non urologic and urologic diseases. In a recent report we demonstrated that both androgen and antiandrogen treatments enhance the proliferation rate of the hormone-dependent prostate cancer cell line LNCaP, expressing a mutated androgen receptor. Simultaneous treatment with 1 nM R1881 and 100 nM OH-Flutamide, completely counteracted the androgen-induced increase of Epidermal Growth Factor (EGF) levels. Moreover we found that Testosterone, DHT and EGF are mainly concentrated in the periurethral zone in human BPH and long term treatment with Finasteride and with Flutamide modify the distribution and concentration of these factors. Some authors analyzed whether and addition of aurin tricarboxylic acid (ATA) can reduce the growth rate of basic FGF-dependent cells in a manner similar to suramin.
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PMID:Peptide growth factors: clinical and therapeutic strategies. 922 27

Androgens play a major role in promoting the growth of the prostate gland. The DHT-androgen receptor complex, by association with the androgen response elements, specifically promotes this androgenic effect on the genome. Also recognized now, however, is that there is a close relationship between this androgen-mediated signalling pathway and those promoted by peptide growth factors, the crosstalk between the pathways being pivotal to growth regulatory control. This is discussed together with the perceived clinical potential of tyrosine kinase inhibitors for the treatment of prostate cancer, when the intracellular signalling, induced by the growth stimulatory factors, can be repressed.
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PMID:Androgens, androgen receptors, antiandrogens and the treatment of prostate cancer. 926 83


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