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)

We report for the first time that a synthetic retinoid, N-(4-hydroxyphenyl)retinamide, can prevent the development of both primary and metastatic tumors in an animal model of metastasizing primary prostate cancer. Prostatic adenocarcinomas were induced in high incidence in Lobund-Wistar rats by initiation with methylnitrosourea i.v. and promotion with testosterone. Feeding of N-(4-hydroxyphenyl)retinamide to these rats during the latency period markedly diminished the final incidence of both primary and metastatic prostate carcinomas.
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PMID:Prevention of primary prostate cancer in Lobund-Wistar rats by N-(4-hydroxyphenyl)retinamide. 182 24

Components of malignant invasion, namely cellular adhesion, motility, and proteolytic capability provide potential sites of pharmacological intervention for malignancy. In this study, a series of experiments were performed to examine the effects of N-(4-hydroxyphenyl) retinamide (4-HPR, Fenretinide) on cellular adhesion, motility and proteolytic activity of established prostate cancer cell lines, TSU-PR 1 and PC-3. Radioadhesion study showed that the treatment of TSU-PR 1 and PC-3 cells with 10(-6) M of 4-HPR resulted in a 32% and 37% reduction (p < 0.05), respectively, in the cellular adhesion to the matrigel extract. Radiomigration assay also demonstrated that 4-HPR concentration of 10(-6) M reduced the cellular motility by 29% in TSU-PR1 and 28% in PC-3 cells (p < 0.05). Spectrolyse PL indirect chromogenic assay revealed an increase in total activatable uPA activity (TSU-PR 1: 25%, PC-3: 32%, P < 0.05), while Spectrolyse UK direct assay demonstrated a mild, but a statistically significant reduction (PC-3: 5%, TSU-PR1: 9%, P < 0.05) in active uPA activity. Northern analysis and ELISA assays showed that 4-HPR at 10(-6) M enhances the expression of type 1 plasminogen activator inhibitor (PAI-1). Type IV collagenase western blot analysis and densitometry did not demonstrate suppression of the enzyme secretion, but in fact suggested increased translation of the enzyme when treated with 10(-6) M concentration of fenretinide. The results of this study demonstrate that 4-HPR inhibits in vitro cellular adhesion and motility of human prostate adenocarcinoma cell lines, TSU-PR1 and PC-3. Additionally, uPA and PAI-1 assay results suggest that 4-HPR may impair active uPA's proteolytic activity while upregulating the expression of total activatable uPA and PAI-1. The results of this study therefore support 4-HPR's role as a potential anti-invasive agent.
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PMID:In vitro anti-invasive effects of N-(4-hydroxyphenyl)-retinamide on human prostatic adenocarcinoma. 765 32

Breast cancer and prostate cancer, the most common cancers in American women and men, respectively, are major public health concerns. Investigations into the prevention and early detection of breast and prostate cancer include research on the potential impact of diet, particularly dietary fat, on breast cancer risk; the chemoprevention of breast cancer using tamoxifen and N-(4-hydroxyphenyl)retinamide(4-HPR); the importance of mammography in early detection of breast cancer; the potential of finasteride in preventing or retarding the progression of early-stage prostate cancer; and improved detection of prostate cancer by combining various screening modalities. The importance of transferring information gained though such research to the health care community cannot be overemphasized. Further, it is critical that cancer prevention and detection education be built into the curricula of leading medical and biomedical institutions. Education is key to developing a strong and vigorous cancer prevention and early detection research program.
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PMID:Expanding horizons in breast and prostate cancer prevention and early detection. The 1992 Samuel C. Harvey Lecture. 836 43

Several epidemiological studies have implicated low dietary and serum levels of retinol with an increased risk for the development of human prostate cancer. In a recent report, dietary fenretinide [N-[(4-hydroxyphenyl)] retinamide], a synthetic retinoid with low toxicity, decreased the incidence of experimentally induced prostate cancer. Fenretinide is currently being evaluated in phase I and phase II clinical trials as an agent for both the treatment and chemoprevention of human prostate cancer. Because of these findings, we investigated whether dietary fenretinide could alter the incidence of phenotype of oncogene-induced prostate cancer in the mouse prostate reconstitution model system. When compared to control-fed animals, dietary fenretinide reduced the tumor incidence by 49% and the tumor mass by 52% of ras+myc-induced cancers in the mouse prostate reconstitution model system, which was modified to prolong the latency period before cancer development. Retinoids have a wide ranging effect on cellular differentiation, growth factor synthesis, and immune function. While its mechanism of action in this system remains unclear, fenretinide is an effective agent for the chemoprevention and growth modulation of oncogene-induced prostate cancer in the mouse prostate reconstitution model system and may be effective for the chemoprevention of human prostate cancer.
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PMID:Dietary fenretinide, a synthetic retinoid, decreases the tumor incidence and the tumor mass of ras+myc-induced carcinomas in the mouse prostate reconstitution model system. 840 13

We measured the electroretinogram to determine whether ocular toxicity exists in men taking oral feretinide, 100 mg daily, for prevention of adenocarcinoma of the prostate. Male subjects at an increased risk for prostate cancer were recruited as volunteers. Fenretinide treatment took place over 1 year with a regimen of 100 mg/day for 25 days with 3 day hiatus intervals. Baseline testing included the electroretinogram Ishihara plates, and the Farnsworth-Munsell D-15 test. Subsequent electroretinographic testing was conducted at 4, 8, 12 and 18 months. Thirteen of 14 subjects maintained normal age-matched electroretinographic responses 6 months after fenretinide treatment. Of these 13 subjects, six showed slight decreases, within 1 standard deviation of the normal mean. Two subjects showed a slight gradual decline of rod-mediated a-wave amplitudes, while b-wave amplitudes were steady. One subject, who had glaucoma, unilaterally fell below normal. After treatment ended, all of the 13 subjects had electroretinographic responses at their respective baseline levels. The subject whose responses fell and remained below 1 standard deviation showed an overall decline in responses and, on follow-up, was diagnosed as having branch retinal vein occlusion, which most likely is the main contributor to the decrease in electroretinographic responses. Our results indicate that men taking 100 mg of oral fenretinide per day for 1 year, with a 3 day hiatus each month, do not show toxicity -induced retinal dysfunction, as measured by the electroretinogram.
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PMID:Electroretinographic findings in subjects after administration of fenretinide. 889

N-(4-Hydroxyphenyl)retinamide (4-HPR, Fenretinide) is a retinoid derivative with antineoplastic activity in various tumor types including prostate carcinoma. The mechanism of action of 4-HPR toxicity is unknown. 4-HPR induces apoptosis in leukemia- and lymphoma-derived cells, neuroblastoma, and small cell lung cancers. The present study was designed to investigate: (a) the mechanism of 4-HPR cytotoxicity in prostate cancer cells; and (b) correlate increased expression of transforming growth factor beta 1 (TGF beta 1) with induction of apoptosis. 4-HPR exposure to PC-3 cells in vitro was associated with apoptosis as evidenced by increased incidence of hypodiploid nuclei in propidium iodide fluorescence histograms and DNA fragmentation. An increase in the percentage of nuclei in the G1 phase of the cell cycle preceded induction of apoptosis. TGF beta 1-increased expression was noted in mRNA levels and in secretion of active TGF beta 1 into culture media. TGF beta 1 and TGF-beta receptor type II detected immunohistochemically were increased in 4-HPR-treated PC-3 cells. Furthermore, 4-HPR-induced cytotoxicity in PC-3 cells was abrogated by the addition of anti-TGF beta 1 antibody. In BT-20 cells, a 4-HPR-resistant breast carcinoma cell line, apoptosis was not observed after exposure to 4-HPR nor was TGF beta 1 expression enhanced in stained cells or in conditioned media. It is concluded that 4-HPR induces the expression of TGF beta 1 in association with the induction of apoptosis.
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PMID:Fenretinide: induction of apoptosis and endogenous transforming growth factor beta in PC-3 prostate cancer cells. 899 39

Prostate cancer is the most common cancer diagnosed in American men. The need to find effective means of preventing this disease is clear. Vitamin A and its analogues (retinoids) act as transcriptional regulators within the nucleus and have been tested as both preventative and therapeutic agents in human malignancy. Fenretinide (N-4-hydroxyphenyl retinamide) (4HPR) has been found to be relatively nontoxic in preclinical experiments and early clinical trials. Its toxicity and feasibility for use as a chemoprevention agent in men at high risk for prostate cancer was evaluated in this study. Twenty-two patients were entered into a clinical trial that involved taking 4HPR for twelve 28-day cycles. Eight patients with negative prestudy biopsies had positive prostate biopsies prior to or at the time of their 12th cycle evaluation. This led to early closure of the study. 4HPR was well-tolerated, and no major toxicities were associated with its use. The significance of this study is limited due to small sample size. Chemoprevention studies such as this can be difficult to complete because of the commitment required of otherwise healthy individuals; nevertheless additional dosages and schedules for 4HPR administration merit further investigation.
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PMID:Phase II chemoprevention trial of oral fenretinide in patients at risk for adenocarcinoma of the prostate. 902 Feb 85

To explore the mechanisms underlying the chemopreventive effects of the synthetic retinoid N-(4-hydroxyphenyl)retinamide (4-HPR) in prostate cancer, we evaluated the anti-proliferative and apoptosis-inducing effects of 4-HPR in the androgen-sensitive human prostate cancer cell line LNCaP. 4-HPR decreased the number of viable LNCaP cells (as measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay) in a dose-dependent manner. Although 4-HPR exerted a modest G1 cell-cycle block (as determined by flow cytometry), its effect on reduced cell number appeared to result primarily from induction of apoptosis (as measured by an enzyme-linked immunosorbent assay and flow-cytometric assays). The mitogenic effects of R1881, a non-metabolizable androgen that potently induces LNCaP cell proliferation, was completely blocked by greater than 0.5 microM 4-HPR. Furthermore, increasing the R1881 concentration in the presence of 2.0 microM 4-HPR increased apoptotic cell death. 4-HPR decreased prostate-specific antigen (PSA) protein levels in conditioned medium and decreased PSA mRNA expression. 4-HPR also decreased the ratio of bcl-2 to bax mRNA expression in LNCaP cells by approximately 45%, indicating that the apoptotic effects of 4-HPR may be mediated, at least in part, by alterations in the bcl-2/bax-regulated apoptotic pathway. N-acetylcysteine (4 mM) completely blocked the anti-proliferative and apoptotic-inducing effects of 4-HPR, suggesting that an oxidative mechanism may be involved. We concluded that (i) 4-HPR exerts growth-suppressive and apoptotic effects on LNCaP cells, (ii) 4-HPR can interact with androgen to suppress proliferation and induce apoptosis, (iii) the apoptotic effects of 4-HPR may be mediated in part by the bcl-2/bax pathway, and (iv) a pro-oxidant mechanism may contribute to the anti-proliferative and apoptotic-inducing effects of 4-HPR.
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PMID:Mechanistic studies of the effects of the retinoid N-(4-hydroxyphenyl)retinamide on prostate cancer cell growth and apoptosis. 1020

The high incidence and long latent period of prostate cancer make it an ideal target for chemoprevention. We have evaluated a series of agents for chemopreventive efficacy using a model in which hormone-dependent prostate cancers are induced in the Wistar-Unilever (WU) rat by sequential treatment with antiandrogen (cyproterone acetate), androgen (testosterone propionate), and direct-acting chemical carcinogen (N-methyl-N-nitrosourea), followed by chronic androgen stimulation (testosterone). This regimen reproducibly induces prostate cancers in high incidence, with no gross toxicity and a low incidence of neoplasia in the seminal vesicle and other non-target tissues. Dehydroepiandrosterone (DHEA) and 9-cis-retinoic acid (9-cis-RA) are the most active agents identified to date. DHEA inhibits prostate cancer induction both when chronic administration is begun prior to carcinogen exposure, and when administration is delayed until preneoplastic prostate lesions are present. 9-cis-RA is the most potent inhibitor of prostate carcinogenesis identified; a study to determine the efficacy of delayed administration of 9-cis-RA is in progress. Liarozole fumarate confers modest protection against prostate carcinogenesis, while N-(4-hydroxyphenyl)retinamide (fenretinide), alpha-difluoromethylornithine, oltipraz, DL-alpha-tocopherol acetate (vitamin E), and L-selenomethionine are inactive. Chemoprevention efficacy evaluations in the WU rat will support the identification of agents that merit study for prostate cancer chemoprevention in humans.
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PMID:Chemoprevention of hormone-dependent prostate cancer in the Wistar-Unilever rat. 1032 6

Chemoprevention is a recently introduced and rapidly growing area of oncology that is identifying agents with a potentially preventive role in cancer. Several clinical trials have recently shown the feasibility of this approach in reducing the risk of major human cancers. In the USA, a large trial that demonstrated a reduction of approximately 50% in the risk of developing breast cancer led to Food and Drug Administration (FDA) approval of tamoxifen as a preventive agent in women at increased risk. Although the results could not be reproduced in two smaller European trials, further investigations into this agent are clearly warranted. Raloxifene, another selective oestrogen receptor modulator which has reduced the risk of breast cancer in a trial in women with osteoporosis, is being compared with tamoxifen in a large primary prevention trial in at-risk women. Retinoids are a group of compounds that have proved especially effective in reducing the occurrence of second primary tumours in subjects with skin, head and neck or liver cancer. Fenretinide, a synthetic retinoic acid derivative, has recently been shown to decrease the occurrence of a second breast malignancy in premenopausal women. Results with non-steroidal anti-inflammatory drugs (NSAIDs) have proved consistently encouraging in epidemiological studies in lowering the incidence of colorectal cancer. Clinical trials with selective cyclo-oxygenase inhibitors potentially devoid of gastrointestinal (GI) toxicity are currently underway in at-risk subjects. Calcium and selenium have also received much attention as chemopreventive agents. Originally investigated against skin cancer, selenium showed efficacy in reducing prostate, lung and colon cancer incidence. Similarly, vitamin E was effective in reducing prostate cancer incidence and mortality in a lung cancer prevention trial in heavy smokers. The challenges of conducting well-designed and unequivocal chemoprevention trials are considerable, but advances in techniques of identification of at-risk subjects and establishing surrogate endpoint biomarkers should contribute greatly to future studies. Current knowledge suggests that a pharmacological approach to preventing cancer, using natural or synthetic agents, could become an important way forward.
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PMID:Recent advances in cancer chemoprevention, with emphasis on breast and colorectal cancer. 1076 41


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