UMLS:C0376358 - FACTA Search

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Query: UMLS:C0376358 (prostate cancer)
59,338 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

PSK, a protein-bound polysaccharide obtained from cultured mycelia of Coriolus versicolor in basidiomycetes, is a biological response modifier, diverse operations of which include an antitumor action. We have previously reviewed recent research which had demonstrated that in animals, PSK has a preventive effect on chemical carcinogen-induced, radiation-induced, and spontaneously developed carcinogenesis (Kobayashi et al., Cancer Epidemiol., Biomarkers & Prev., 2: 271-276, 1993). We now focus on the effects of PSK once the progression of carcinogenesis has begun, and review what is now known of the preventive action of PSK on cancer metastasis. Recent research reports that PSK suppresses pulmonary metastasis of methylcholanthrene-induced sarcomas, human prostate cancer DU145M, and lymphatic metastasis of mouse leukemia P388, and that it has prolonged the survival period in spontaneous metastasis models. PSK also suppresses the metastasis of rat hepatoma AH60C, mouse colon cancer colon 26, and mouse leukemia RL male 1 in artificial metastasis models. PSK influences the steps of cancer metastasis in a number of ways: (a) by suppression of intravasation through the inhibition of tumor invasion, adhesion and production of cell matrix-degrading enzymes; (b) by suppression of tumor cell attachment to endothelial cells through the inhibition of tumor cell-induced platelet aggregation; (c) by suppression of tumor cell migration after extravasation through the inhibition of tumor cell motility; and (d) by suppression of tumor growth after extravasation through the inhibition of angiogenesis, the modulation of cytokine production, and the augmentation of effector cell functions. In addition, PSK has suppressed the malignant progression of mouse tumor cells through superoxide trapping.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Antimetastatic effects of PSK (Krestin), a protein-bound polysaccharide obtained from basidiomycetes: an overview. 760 3

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

We have previously documented the presence of specific insulin-like growth factor (IGF)-binding protein (IGFBPs) in seminal plasma and prostate epithelial cell-conditioned medium IGFBP-2 is the prevalent IGFBP in both fluids. To assess whether patients with prostate carcinoma have alterations in serum IGFP levels related to the production of IGFBPs by their tumors, we performed Western ligand blots (WLB) and IGFBP-2 RIA on serum samples from 32 patients with prostate carcinoma of various degrees of clinical severity and compared them to results in 16 healthy age-matched controls. We have also measured serum IGF-I and -II by RIA. The mean level of IGFBP-2 in the prostate cancer patients was 170% of control levels by WLB analysis and 195% of control levels by RIA (P < 0.01). The degree of elevation of IGFBP-2 was related to the stage of the tumor and the levels of the serum tumor marker, prostate-specific antigen. Serum IGFBP-3 levels determined by WLB and serum IGF-I and IGF-II levels measured by RIA after acid chromatography were not different among the subjects with cancer and the normal controls. We conclude that IGFBP-2, which is the main IGFBP produced by prostate epithelial cells, is elevated in the serum of patients with prostate carcinoma, and that the degree of this elevation is related to serum prostate-specific antigen levels and the stage of the tumor. We speculate that prostate-derived IGFBPs may be secreted by prostate tumors and could e of value in understanding the pathophysiology of prostatic tumor growth as well as provide potential diagnostic markers.
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PMID:Elevated levels of insulin-like growth factor-binding protein-2 in the serum of prostate cancer patients. 768 60

The serum marker prostate-specific antigen (PSA) has been shown to be proportional to the volume of prostate cancer (Yang polyclonal assay). Therefore, changes in PSA with time in untreated patients should reflect tumor growth rate and the shape of the growth curve. Forty-three patients with untreated prostate cancer had serial PSA measurements over an average time span of 30 months. The increase of PSA was exponential (log-linear) throughout the measured interval. Doubling times were faster in patients with higher stages and grades. Twenty of 28 cancers thought to be clinically organ confined doubled at rates exceeding 4 years. Tumor doubling times were overestimated in patients with large volume benign prostatic hyperplasia since hyperplasia increases serum PSA, albeit 12 times less than cancer. We conclude that prostate cancer has a constant (log-linear) growth rate which is very slow. This slow doubling time has substantial consequences for therapeutic decisions and for screening programs.
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PMID:Clinical observations on the doubling time of prostate cancer. 768 4

The angiogenesis inhibitor O-(chloroacetyl-carbamoyl)fumagillol (TNP-470) showed antitumor activity in three human cancer xenograft systems. TNP-470 potently inhibited the tumor growth of hormone-independent prostate cancer PC-3 cells and breast cancer MDA-MB-231 cells dose dependently at weekly s.c. doses of 50-200 mg/kg with maximum inhibition of 96 and 88% (tumor growth, 4 and 12% of that in the respective control). In experiments of combination therapy with chemotherapeutic agents, the combination of TNP-470 (100 mg/kg) and cisplatin (5 mg/kg) showed an additive antitumor effect (from treated versus control, 38 and 22% to 5%) against PC-3 carcinoma. 5-Fluorouracil and Adriamycin alone did not significantly inhibit MDA-MB-231 tumor growth (treated versus control, 131 and 64%, respectively). TNP-470 also inhibited tumor growth of WiDr colon cancer; although the inhibition was less marked (treated versus control, 39%) than that observed with the hormone-independent cancers used in this study. In an in vitro study, all the cell lines tested were considerably insensitive to TNP-470 in monolayer cultures (50% inhibitory concentration, approximately 5 micrograms/ml), whereas TNP-470 inhibited the anchorage-independent growth of PC-3 and MDA-MB-231 cells (50% inhibitory concentration, 0.05 and 470 ng/ml, respectively). The inhibitory activity of TNP-470 against anchorage-independent growth correlated well with the in vivo antitumor activity among the cell lines tested. Thus, this inhibitory action may partly contribute to the potent antitumor activity of the angiogenesis inhibitor TNP-470, at least in the case of PC-3 and MDA-MB-231. These results suggest that hormone-independent prostate and breast cancers may be appropriate target diseases for TNP-470 clinical trials.
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PMID:Angiogenesis inhibitor TNP-470 (AGM-1470) potently inhibits the tumor growth of hormone-independent human breast and prostate carcinoma cell lines. 769 35

Antiandrogens have sporadically been reported to exert antitumor activities in both pre- and post-menopausal breast cancer. To explore the possibility of using the pure antiandrogen flutamide (FLU) in breast cancer therapy, rats bearing DMBA-induced mammary tumors were treated with FLU, dihydrotestosterone (DHT), or FLU plus DHT. FLU was administered orally, at doses comparable to those used in the treatment of prostate cancer patients. FLU-treated animals had a significantly smaller average tumor area than controls from day 11 up to the end of the experiment (day 20). A similar reduction of tumor growth was observed in rats given DHT and in those treated with DHT plus FLU. Plasma levels of LH, FSH, P, 17-OH P, E2 and DHEA measured at the end of experiment did not differ between treated animals and controls. Results demonstrate that the antiandrogen FLU and the full androgen DHT exert similar inhibitory effects on the growth of dimethylbenz(a)anthracene (DMBA)-induced rat mammary tumors. Moreover, data show that plasma steroids levels are unaffected by FLU treatment. This finding rules out any antitumor effect dependent on the reduction of adrenal and gonadal steroidosynthesis, and makes it appear more likely that androgen receptors are involved in the antiproliferative effect of FLU.
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PMID:Growth inhibition of DMBA-induced rat mammary carcinomas by the antiandrogen flutamide. 771 86

Radiation therapy for advanced prostate cancer has dose-limiting complications and often results in limited tumor control. A combination of radiation and taxol, a potential radiation sensitizer, may enhance therapeutic efficacy at currently used individual doses. Human prostatic carcinoma lines in vitro, and Dunning rat prostatic adenocarcinoma in vivo, were treated with taxol and radiation individually, and in combination. Cytotoxicity of taxol was comparable between androgen sensitive and insensitive lines, with 50% growth inhibition at 9.6 to 12.7 nM. Combining agents increased cytotoxicity, with a dose modifying ratio of 1.8 at 0.1% survival. Flow cytometry showed an enhancement of radiation toxicity associated with taxol-induced cell cycle phase arrest at G2/M. Injection of taxol (4 mg/kg/day x 5), radiation dose fractionation (1.5 Gy/day x 5) and their combination significantly delayed Dunning tumor growth. Adverse side effects were minimal. The results imply that combination of these agents may have clinical potential in prostate cancer treatment.
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PMID:Enhancement of radiation response of prostatic carcinoma by taxol: therapeutic potential for late-stage malignancy. 773 49

Poorly differentiated MATLyLu rat prostate cancer cells are resistant to the growth inhibitory effect of transforming growth factor (TGF) beta 1 in vivo, but are inhibited by TGF-beta 1 in vitro. However, TGF-beta 1 inhibited proliferation only when the cells were plated at low density in serum-free medium (concentration for 50% of maximum inhibition, 0.1 ng/ml). TGF-beta 1 was not growth inhibitory when cells were plated at high density, or at low density in 0.5% serum. At low cell density in serum-free medium, 0.5 ng/ml TGF-beta 1 caused maximum inhibition. In the presence of basic fibroblast growth factor (10 ng/ml), TGF-beta 1 did not inhibit proliferation. In the presence of epidermal growth factor (50 ng/ml), TGF-beta 1 inhibited proliferation by only 18%. Growth inhibition by TGF-beta 1 was less effective on extracellular matrix than on plastic. The ability of high cell density, serum, growth factors, or extracellular matrix to prevent or blunt the growth inhibitory effect of TGF-beta 1 in vitro probably explains why TGF-beta 1 does not inhibit tumor growth in vivo. Thus, prostate cancer cells express high levels of TGF-beta and retain exquisite sensitivity to the growth inhibitory effect of TGF-beta, but have devised a way to protect themselves from growth inhibition by TGF-beta in vivo. TGF-beta 1 stimulated MATLyLu cell motility even at high cell density, suggesting that TGF-beta 1 might affect motility even in vivo and contribute to the aggressiveness of the tumor, without affecting proliferation.
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PMID:Modulation of transforming growth factor beta 1 effects on prostate cancer cell proliferation by growth factors and extracellular matrix. 778 Sep 74

The long-acting synthetic somatostatin analog, SMA 201-995, was used to treat patients with advanced hormonal-refractory prostate cancer. Twenty-two of 24 study patients treated are evaluable for toxicity and 20 are evaluable for response. The dose of SMS 201-995 was 100 mg subcutaneously every 8 hours for 6 weeks. Two patients suffered intolerable gastrointestinal complications requiring early cessation of therapy. No patient had objective evidence of tumor regression. After developing a clinical suspicion that tumor growth accelerated with SMS 201-995, we observed 10 patients closely for 2 months before beginning SMS 201-995 treatment and for the first 2 months on the therapy. In these 10 patients, the serum prostatic acid phosphatase level rose at an accelerated rate after 1 to 2 months of treatment. Among the 20 patients treated and evaluable for response, new osseous metastases developed in 12 and new visceral metastases in 4; 1 developed disseminated intravascular coagulation and 2 developed neurologic complications (mean time to objective progression, 5.6 weeks). Six patients received salvage chemotherapy after disease progressed on SMS 201-995 therapy, 5 of whom have achieved objective tumor regressions. We believe SMS 201995 stimulates prostatic tumor growth and may sensitize tumor cells to subsequent chemotherapy.
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PMID:SMS 201-995 in the treatment of refractory prostatic carcinoma. 787 9

Nude mice bearing xenografts of the androgen-independent human prostate-cancer cell line PC-3 were treated for 4 weeks with somatostatin analog RC-160, bombesin/gastrin-releasing peptide (GRP) antagonist (RC-3095), or the combination of both peptides. In the first experiment, treatment was started when the tumors measured approximately 10 mm3. Tumor volumes and weights were reduced by about 40% by RC-160 or RC-3095 administered by s.c. injections at doses of 100 micrograms/day/animal and 20 micrograms/day/animal respectively. The combination of RC-3095 with RC-160 did not further potentiate suppression of tumor growth, but histologically the ratio of apoptotic and mitotic indices was significantly higher in the groups treated with the combination than in the other groups. Serum gastrin levels were significantly reduced in all treated groups. Therapy with RC-160 or the combination also significantly decreased serum growth-hormone levels. Specific high-affinity binding sites for bombesin, somatostatin and epidermal growth factor (EGF) were found on the tumor membranes. Receptors for EGF were significantly down-regulated by treatment with RC-3095, RC-160 and a combination of both analogs. Tumors from mice treated with RC-160 showed a significant increase in maximal binding capacity for somatostatin as compared with control tumors, demonstrating the absence of down-regulation. In the second experiment, treatment was started when the tumors were well developed and measured approximately 90 mm3. No significant reduction in volume, weight and growth rate of tumors was found in the groups treated with RC-160 or RC-3095. Our results suggest that somatostatin analog RC-160 and bombesin/GRP antagonist RC-3095 can inhibit the growth of androgen-independent prostate cancer when the therapy is started at an early stage of tumor development.
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PMID:Effect of somatostatin analog RC-160 and bombesin/gastrin releasing peptide antagonist RC-3095 on growth of PC-3 human prostate-cancer xenografts in nude mice. 790 29

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