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

Retinoids play a major role in regulation of epithelial cell growth and cellular differentiation, but their mechanism(s) of action are still unclear. In the present study, we examined the effects of 13-cis-retinoic acid (13-cis-RA) on cytotoxicity, growth properties, morphology, neutral lipids, phospholipids and fatty acids in cultured human prostate cancer cell lines. The results of these experiments suggest that 13-cis-RA (10 microM) inhibits the DNA synthesis and nude mice tumorigenicity by 2- to 3-fold, compared to control. Electron microscopy revealed more differentiated phenotypes after 13-cis-RA treatment. There was a significant increase in phosphatidylcholine and decrease in sphingomyelin in 13-cis-RA treated cells compared to control. The saturated fatty acids significantly decreased whereas unsaturated fatty acids were increased after 13-cis-RA treatment in prostate cancer cells. This study demonstrates for the first time that retinoic acid mediated downregulation of saturated fatty acids and upregulation of unsaturated fatty acid in human prostate cancer cells.
 ...
PMID:Downregulation of saturated fatty acid and upregulation of unsaturated fatty acid by 13-cis-retinoic acid in human prostate cancer cells. 129 Apr 70

Liarozole reduced tumor growth in the androgen-dependent Dunning-G and the androgen-independent Dunning MatLu rat prostate carcinoma models as well as in patients with metastatic prostate cancer who had relapsed after orchiectomy. In vitro, liarozole did not have cytostatic properties, as measured by cell proliferation in breast MCF-7 and prostate DU145 and LNCaP carcinoma cell lines. It did not alter the metabolism of labeled testosterone i.e. the 5 alpha-reductase in cultured rat prostatic cells. In mouse F9 teratocarcinoma cells liarozole did not show any retinoid-like properties but enhanced the plasminogen activator production induced by retinoic acid. Furthermore, liarozole and retinoic acid similarly reduced the growth of the androgen-dependent Dunning-G tumor in nude mice and inhibited tumor promotion elicited by phorbol ester in mouse skin. These data have raised the hypothesis that the antitumoral properties of liarozole may be related to inhibition of retinoic acid degradation, catalyzed by a P-450-dependent enzyme that is blocked by the drug.
 ...
PMID:Experimental studies with liarozole (R 75,251): an antitumoral agent which inhibits retinoic acid breakdown. 152 60

The effect of retinoic acid (RA) on testosterone metabolism was examined in a prostatic cancer cell line of human origin, PC-3. In cells growing as monolayers as well as in cell homogenates RA causes a dose-dependent inhibition of the 5 alpha-reductase activity, thus preventing the conversion of testosterone into its hormonally active metabolite, dihydrotestosterone. Fifty per cent inhibition of the enzyme activity occurred at an RA concentration of 2 x 10(-5)M. The pattern of inhibition was that of a non-competitive inhibitor. However, when incubations were performed in the presence of varying amounts of NADPH, it turned out that RA exerts its effect by competitive inhibition of the cofactor action. Although the severe toxicity of RA precludes its systemic use as a 5 alpha-reductase inhibitory drug in humans, the possible anti-androgenic effect of other, less toxic, retinoids should be investigated.
 ...
PMID:Retinoic acid (RA): an inhibitor of 5 alpha-reductase in human prostatic cancer cells. 369 21

Overproduction of uPA by prostate cancer cells in vivo results in tumor invasiveness and osteoblastic skeletal metastasis due to its mitogenic actions in osteoblasts. In the present study we have examined the effect of several growth factors and steroid hormones on regulating uPA gene expression in the human prostate cancer cell line (PC-3). Treatment of these cells with dexamethasone (Dex) caused a decrease, whereas epidermal growth factor (EGF) and fetal bovine serum (FBS) increased uPA expression in a dose-dependent manner. Trans retinoic acid (RA) also induced uPA mRNA and protein production in a dose-dependent manner (10(-6) to 10(-9) M). This increase was seen as early as 2 hr of treatment until 48 hr. Dex treatment resulted in decreased tumor cells invasiveness, whereas exposure to EGF and RA caused an increase in the invasive capacity of PC-3 cells. These studies should help to better understand the control mechanism of uPA expression in prostate cancer, where uPA has been implicated as a major pathogenetic factor.
 ...
PMID:Induction of urinary plasminogen activator by retinoic acid results in increased invasiveness of human prostate cancer cells PC-3. 747 94

Prostate-specific antigen (PSA) is a member of the kallikrein family and has been an important biological marker for prostate cancer. The mechanisms regulating PSA expression in prostatic cancer cells are unclear. The present study was designed to elucidate the role of 13-cis-retinoic acid (RA) in regulation of PSA and the tumorigenic potential of the human prostate cancer cell line LNCaP. The growth regulation of LNCaP cells was examined by DNA synthesis and doubling time. The tumorigenic potential of prostate cancer cells was analyzed by soft agar colony-forming assay, in vitro invasion assay, type IV collagenase assay and binding to extracellular matrix assay. The nuclear receptors for retinoic acid (RAR alpha, -beta, -gamma and RXR alpha, -beta, -gamma) as well as PSA mRNA were determined by Northern blot using specific oligonucleotide probes. Our results suggest that 13-cis-RA significantly inhibits PSA secretion and expression both at the mRNA and protein levels compared with untreated cells. Electron microscopic studies suggest that after 13-cis-RA treatment, cells become more differentiated as they contain lumina, lined by plasma membrane and microvilli. Prostate cancer cell growth and tumorigenic potential after 13-cis-RA treatment was significantly decreased compared with controls. Nude mice tumorigenicity studies showed that 13-cis-RA-treated cells produced significantly smaller tumors compared with untreated cell tumors. There was also a significant increase in the expression of RXRa mRNA after 13-cis-RA treatment compared with untreated cells.
 ...
PMID:Inhibition of tumorigenic potential and prostate-specific antigen expression in LNCaP human prostate cancer cell line by 13-cis-retinoic acid. 752 13

N-4-Hydroxyphenylretinamide (fenretinide or 4HPR), a derivative of retinoic acid, has been demonstrated to decrease the development of prostate cancer in a rat carcinogenesis model. This study was undertaken to determine if 4HPR is an effective agent for the treatment of established prostate cancer. In vitro, 4HPR was cytotoxic to rat and human prostate cancer cells as well as endothelial cells. Utilizing three different angiogenesis inhibition assays, it was demonstrated that 4HPR inhibited angiogenesis as well as endothelial cell motility and tubule formation. In vivo, 4HPR inhibited prostate cancer growth in a significant manner. These findings suggest that 4HPR may be a potent inhibitor of early prostate cancer growth.
 ...
PMID:Treatment of prostate cancer in the rat with the synthetic retinoid fenretinide. 767 70

The present study was designed to investigate the effects of 13-cis-retinoic acid (13-cis-RA) (100 micrograms/mouse/day) and androgen ablation (castration) alone and in combination on growth of a human prostatic carcinoma line (LNCaP) transplanted to athymic nude mice as an experimental model. The results of these studies suggest that; (1) androgen ablation (castration) significantly decreased the size of LNCaP xenograft as compared to untreated animals; (2) when 13-cis-RA was administered to nude mice carrying established tumors (0.51 +/- 0.04 cm3), the tumor size was significantly reduced as compared to untreated controls (0.65 +/- 0.06 cm3 versus 1.63 +/- 0.12 cm3). About 50% of the animals in this group showed xenografts necrosis followed by complete regression of tumors by five months; (3) the combination of androgen ablation and 13-cis-RA treatment to nude mice carrying tumors showed synergistic effect in decreasing the tumor size. These results indicate that combination therapies based on androgen ablation and retinoid administration may be a useful approach for the treatment of prostate cancer.
 ...
PMID:Regression of LNCaP human prostate tumor xenografts in athymic nude mice by 13-cis-retinoic acid and androgen ablation. 777 85

Hereditary peculiarities in individual responses to environmental chemicals are a common occurrence in human populations. Genetic variation in glutathione S-transferase, CYP1A2, N-acetyltransferase, and paraoxonase exemplify the relationship of metabolic variation to individual susceptibility to cancer and other toxicants of environmental origin. Heritable receptor protein variants, a subset of proteins of enormous pharmacogenetic potential that have not thus far been extensively explored from the pharmacogenetic standpoint, are also considered. Examples of interest that are considered include receptor variants associated with retinoic acid resistance in acute promyelocytic leukemia, with paradoxical responses to antiandrogens in prostate cancer, and with retinitis pigmentosa. Additional heritable protein variants of pharmacogenetic interest that result in antibiotic-induced deafness, glucocorticoid-remediable aldosteronism and hypertension, the long-QT syndrome, and beryllium-induced lung disease are also discussed. These traits demonstrate how knowledge of the molecular basis and mechanism of the variant response may contribute to its prevention in sensitive persons as well as to improved therapy for genetically conditioned disorders that arise from environmental chemicals.
 ...
PMID:Influence of heredity on human sensitivity to environmental chemicals. 778 56

Genitourinary cancers--bladders, testis and prostate--account for almost 50,000 deaths per year. Epidemiologic data suggest that individuals with low serum retinoid levels or low dietary intake of retinoid-containing foodstuffs have an increased risk of bladder and prostate cancer. Preclinical investigations show that a variety of retinoids suppress the proliferation of prostate and bladder cancer cells and induce differentiation in teratocarcinoma cells. Retinoids prevent the emergence of murine bladder and prostate cancers in carcinogen-treated animals. Clinical data are disappointing or inconclusive. A single well-conducted phase 2 trial of 13-cis retinoic acid in patients with germ cell tumors was negative. Several historically controlled as well as prospectively randomized, placebo-controlled trials of retinoids in superficial bladder cancer have failed to provide evidence of the efficacy of retinoids. Two studies of all-trans-retinoic acid in advanced prostate cancer have been negative. Despite compelling preclinical rationale, retinoids have failed to yield positive results in the clinical management of prostate, bladder or testis cancers. Further work is needed to define subsets of patients in whom retinoids might be active, and whether new retinoids or new approaches to retinoid delivery will improve the clinical usefulness of retinoids in these tumors.
 ...
PMID:Retinoids in bladder, testis and prostate cancer: epidemiologic, pre-clinical and clinical observations. 780 25

Chemoprevention is a strategy used to block the development of cancers in human beings. This emerging field has broad potential for influencing cancer incidence rates in defined high-risk groups and the general population. In this review, we define some of the mechanisms of carcinogenesis, describe some of the genetic markers of carcinogenesis, and list possible biomarkers that may serve as surrogate end points in chemoprevention studies. A major component of this review is a description of the agents that are currently under investigation in animal systems or in human trials. They are grouped according to the agents that block or suppress mutation, such as oltipraz, selenium, vitamin C and the flavones, or according to agents that block promotion and proliferation, such as difluoromethylornithine, tamoxifen, nonsteroidal antiinflammatory drugs, and the vitamin A derivatives. We describe the issues that are considered in the design of chemoprevention trials and in the phase I, II, and III components of these trials. The following national trials are discussed: the Breast Cancer Prevention Trial, which uses tamoxifen; the Prostate Cancer Prevention Trial, which uses finasteride; and a Lung Cancer Prevention Trial, which uses 13-cis-retinoic acid. The review ends with some insights about future studies in chemoprevention.
 ...
PMID:Chemoprevention of cancer. 800 1


1 2 3 4 5 6 7 8 9 10 Next >>