Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

MDL 101,731, (E)2'-fluoromethylene-2'-deoxycytidine, is an irreversible inhibitor of ribonucleotide diphosphate reductase and causes regression of human tumors in nude mouse models. Messenger RNA levels for testosterone-repressed prostatic message-2 (TRPM-2), a transcript that increases in human tumor xenografts undergoing programmed cell death, were analyzed by in situ hybridization. Xenografts derived from a human prostate tumor cell line (PC-3) regressed following treatment with MDL 101,731 and the relative levels of TRPM-2 mRNA increased up to threefold in drug-treated animals. Apoptosis in the tumor xenografts was further indicated by in situ labeling of DNA strand breaks by incorporation of biotinylated-dUTP with terminal deoxynucleotidyl transferase. In vitro, PC-3 cells incubated with MDL 101,731 showed evidence of apoptosis based on flow cytometry and DNA laddering. These data support the hypothesis that MDL 101,731 stimulates programmed cell death in regressing PC-3 xenografts.
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PMID:A ribonucleotide reductase inhibitor, MDL 101,731, induces apoptosis and elevates TRPM-2 mRNA levels in human prostate tumor xenografts. 854 73

The therapeutic potential of the somatostatin analogue RC-160 radiolabeled with 188Re was evaluated in nude mice bearing xenografts of human prostate adenocarcinoma. 188Re-RC-160 was selectively retained in both DU-145 and PC-3 tumors following direct intra-tumor injection at all time points examined (2, 6 and 24 hr post-injection). Unbound 188Re-RC-160 was rapidly excreted via the hepatobiliary system and, with the exception of the gastrointestinal tract, very little normal organ uptake was found at any time point examined. Negative control compounds, 188Re-perrhenate and 188Re-mercaptoacetyl-triglycine (188Re-MAG3), were essentially washed out of the tumor by 6 hr post-injection and were rapidly excreted through the kidneys. 131I-RC-160, used as reference compound, had a biodistribution in tumor-bearing animals similar to that of 188Re-RC-160. In PC-3 xenografts, 188Re-RC-160 gave a dose-dependent therapeutic response (stasis or regression) even in animals with relatively large tumor masses (greater than 600 mm3), whereas the macro-aggregated form of 188Re-RC-160 did not. Long-term studies with 188Re-RC-160 demonstrated a protracted reduction of tumor volume and a positive effect on animal survival. Neither RC-160 by itself nor a 188Re-labeled peptide, unrelated to somatostatin (PA-22-2, a laminin peptide), demonstrated the reduction in tumor mass observed with 188Re-RC-160. 188Re-RC-160 shows potential as a new clinical agent for treatment of somatostatin-receptor-positive cancers.
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PMID:Experimental radiotherapy of receptor-positive human prostate adenocarcinoma with 188Re-RC-160, a directly-radiolabeled somatostatin analogue. 856 20

We have cloned and characterized a 620-bp fragment of DNA that flanks 5' of the prostate-specific antigen (PSA) gene from a prostate cancer patient. Using DNA transfection, the efficacy of this putative promoter in regulating gene expression was quantitated in several prostate and nonprostate tissue cell lines. Our results demonstrated that the 620-dp DNA fragment actively drives gene expression in LNCaP, a PSA-producing prostate tumor cell line. No promoter activity was detected in the non-PSA-producing prostate tumor lines, DU145 and PC-3, nor in a renal (R11) or breast (MCF-7) cancer cell line. Furthermore, the promoter activity could be regulated in vitro by androgen stimulation. Dihydrotestosterone (DHT) concentrations between 3 and 30 nM induced the highest promoter activity in the transfected LNCaP cells, which parallels the expression profile of the androgen receptor in LNCaP cells. In addition, our PSA promoter exhibited competitive inhibition of the endogenous genomic PSA promoter in transfected LNCaP cells, suggesting that prostate cell-specific DNA-binding proteins are required to activate the PSA promoter. increased its potency four- to five-fold while retaining tissue specificity. Our data suggest that a strong tissue-specific negative regulatory element capable of overriding the nonspecific CMV promoter is present in the PSA promoter and confers its tissue specificity. The use of a highly specific promoter-driven gene vector will allow selective expression of therapeutic genes within PSA-producing prostate cancer cells, providing a unique strategy for prostate cancer gene therapy.
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PMID:Prostate tissue specificity of the prostate-specific antigen promoter isolated from a patient with prostate cancer. 857 14

The RRR-alpha-tocopheryl succinate derivative of vitamin E, referred to as vitamin E succinate (VES), inhibits the proliferation of three metastatic human prostatic cancer cell lines, LNCaP, PC-3, and DU-145. LNCaP is a lymph node-derived androgen-sensitive prostate cell line; these cells are defective for response to transforming growth factor-beta (TGF-beta) but are normal for cell cycle-related tumor suppressor genes: p53 and retinoblastoma (Rb). PC-3 is a bone marrow-derived androgen-insensitive prostate cell line; these cells are defective for both p53 alleles but normal for both Rb alleles. DU-145 is a brain-derived androgen-insensitive prostate cell line; these cells are defective for both p53 and both Rb alleles. VES at 5, 10, and 20 micrograms/ml inhibited DNA synthesis in the three cell lines in a dose-dependent manner. Purified TGF-beta 1 at 1 ng/ml inhibited DNA synthesis of PC-3 cells within 24-72 hours and DU-145 cells at 72 hours but did not inhibit DNA synthesis of LNCaP cells. Previous studies in our laboratory showed that VES growth-inhibited tumor cells secrete biologically active antiproliferative factor TGF-beta s, suggesting that VES's mechanism of growth inhibition may involve the TGF-beta system of growth control.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:RRR-alpha-tocopheryl succinate inhibits the proliferation of human prostatic tumor cells with defective cell cycle/differentiation pathways. 858 52

The production of tumor cell proteases is implicated in tumor cell invasion and metastasis. To determine whether lung cancer cells can produce polymorphonuclear leukocyte elastase (PMN-E), we measured the concentration of immunoreactive (ir)-PMN-E in the conditioned medium of seven lines of non-small cell lung cancer cells, EBC-1, LC-1sq, LK-2, A-549, PC-3, RERF-LC-MS, and RERF-LC-OK, and three normal lung epithelial cell lines, CCD-8Lu, WI-1003, and LL-24, by using a recently developed enzyme immunoassay (EIA). We measured the concentration of ir-PMN-E in extracts of 40 non-small cell lung cancers, and evaluated its association with the clinicopathologic findings in these patients. The ir-PMN-E level in the culture medium increased with time in six of the seven lines of lung cancer cells; the exception was PC-3. No detectable ir-PMN-E was secreted into the culture medium of the three lines of normal lung epithelial cells. The ir-PMN-E was detected in tissue extracts from 34 to 40 specimens at concentrations ranging from 0.11 to 15.5 micrograms/100 mg of protein. When 40 specimens of lung cancer were categorized by clinical stage of disease, the ir-PMN-E concentration was significantly higher in stage IIIB vs stages I, II, or IIIA. Similarly, the ir-PMN-E concentration was significantly higher in stage IIIA than in stage I. Evaluation of correlations between the ir-PMN-E concentration and patient characteristics showed that the ir-PMN-E level was significantly higher in T3 and T4 tumors than in T1 or T2 tumors. Analysis of prognostic factors in a group of 101 patients with non-small cell lung cancer demonstrated that those with high ir-PMN-E had a significantly shorter overall survival vs those with a low ir-PMN-E at the cutoff point of 3.5 micrograms/100 mg of protein. Multivariate analysis showed that ir-PMN-E was a significant porgnostic factor for early death (hazard ratio, 4.04; 95% confidence interval, 1.65 to 9.95) (p = 0.005), suggesting it was an independent marker for prognosis. Results suggest that the local production of PMN-E may be involved in the tumor invasion associated with a poor prognosis in patients with non-small cell lung cancer.
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PMID:Local increase in polymorphonuclear leukocyte elastase is associated with tumor invasiveness in non-small cell lung cancer. 862 86

Gemcitabine (2',2'difluoro-2'deoxycytidine, dFdC) is a synthetic antimetabolite of the cellular pyrimidine nucleotide metabolism. In a first series of in vitro experiments, the drug showed a strong effect on the proliferation and colony formation of the human androgen-sensitive tumor cell line LNCaP and the androgen-insensitive cell lines PC-3 and DU-145. Maximal inhibition occurred at a dFdC concentration as low as 30 nM. In contrast to the cell lines which were derived from metastatic lesions of prostate cancer patients, no inhibitory effects were found in normal primary prostatic epithelial cells at concentrations up to 100 nM. The effect of gemcitabine was reversed by co-administration of 10-100 microM of its natural analogue deoxycytidine. In view of a future clinical application of this anti-tumor drug in advanced prostatic carcinoma, we have compared the effect of gemcitabine on prostatic tumor cells with that on bone marrow granulopoietic-macrophage progenitor cells, because neutropenia is a common side effect of gemcitabine treatment. The time course of action on the two kinds of cells was markedly different. Colony formation of tumor cells was inhibited by two thirds at a gemcitabine concentration of about 3.5 nM. The same effect on granulopoietic-macrophagic progenitor cells required a concentration of 9 nM. Co-administration of deoxycytidine to gemcitabine-treated tumor cell cultures completely antagonized the effect of gemcitabine whereas addition of deoxycytidine after 48 hr of gemcitabine treatment could not prevent gemcitabine action on the tumor cells. In contrast, more than half of the granulopoietic-macrophagic progenitor cells could still be rescued by deoxycytidine administration after 48 hr. These findings and the marked difference in the susceptibility of neoplastic and normal prostatic cells suggest that gemcitabine is a promising substance which should be further evaluated as to its efficacy in the treatment of advanced prostatic carcinoma.
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PMID:Inhibitory effects of the nucleoside analogue gemcitabine on prostatic carcinoma cells. 862 20

Previously we reported hemorrhagic necrosis in human-derived PC-3 prostate tumors, in athymic nude mice, produced by the intralesional injection of antisense oligonucleotides (oligos) directed against mRNAs encoding transforming growth factor-alpha (TGF-alpha) and its target, the epidermal growth factor receptor (EGFR). We now describe our experience with these oligos in treating additional mice with various doses and modes of administration. During prolonged treatment, a dose-response effect was observed, with the optimal dosage consisting of the combination of 400 micrograms of each oligo. Although responses varied, based upon amount and how oligos were administered, we found that tumors were best treated when initially less than 156 mm3. Intralesional inoculations produced necrosis and yielded responses, ranging from complete response (CR) or cure to partial responses (PR) in 9 of 12 tumors treated with full dose (400 micrograms of each oligo) and 1 of 1 treated with 800 micrograms of each oligo, against a large tumor. Included among the 9 positive responses with full-dose administration were 2 tumors that regressed (one completely). A single tumor treated with twice (2X) the normal dosage (800 micrograms of each oligo) also regressed. A single tumor treated with half (1/2) dose (200 micrograms of each) progressed similar to controls, as did 3 of 12 treated with the full dose. Limited experience with ALZET diffusion pumps gave CR (1 of 3) or PR (2 of 3) in 100% of tumors treated (including one mouse cured of multiple tumors in a five day period). It appears that multiple inoculations consisting of 400 micrograms of each oligo is most effective against these tumors, particularly when administered against tumors of <156 mm3 in initial size.
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PMID:Antisense oligonucleotide intralesional therapy for human PC-3 prostate tumors carried in athymic nude mice. 866 27

Expression of urokinase-type plasminogen activator (uPA) by malignant cells correlates with an aggressive phenotype, including increased invasiveness, tumor-associated angiogenesis, and metastases. Plasminogen activator inhibitor type 1 (PAI-1) is undetectable in cells of some aggressive malignancies, but present in the stroma of tumor-associated microvasculature. This analysis of an athymic mouse model of prostate carcinoma further defines the role of the uPA/PAI-1/plasmin system in primary growth and metastasis. A marked increase in PAI-1 expression was induced in clones of the aggressive human prostate carcinoma line, PC-3, by stable transfection. Primary PC-3 tumors, in mice, were significantly smaller when derived from PAI-1 expressing versus control cells. PAI-1 expression reduced the density of tumor-associated microvasculature by 22-38%. Microscopic metastases were quantitated using stable expression of the chromogenic label (beta-galactosidase) in control and PAI-1 expressing cells. PAI-1 expression resulted in a significant inhibition of lung metastases, and liver metastases. Expression of PAI-1 by malignant prostate cells resulted in a less aggressive phenotype, presumably by inhibition of uPA activity, suggesting pharmacologic or molecular inhibition of uPA activity as a potential therapeutic target.
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PMID:Expression of plasminogen activator inhibitor type 1 by human prostate carcinoma cells inhibits primary tumor growth, tumor-associated angiogenesis, and metastasis to lung and liver in an athymic mouse model. 867 23

The PC-3 human prostatic carcinoma cell line has been extensively used as a model for studies on the regulation of prostate tumor cell proliferation. Because of the importance of IGF-binding proteins (IGFBPs) in the control of IGF activities that regulate cell proliferation in normal and malignant cell types, we undertook studies to characterize the IGFBPs produced by PC-3 prostate tumor cells in culture. We previously found, using an IGF-I affinity column for purification and a polyethylene glycol (PEG) precipitation assay for IGFBP detection, that PC-3 cells in culture produced a single predominant IGFBP, IGFBP-4, which inhibits IGF activities. We now present evidence that PC-3 cells also produce IGFBP-6 in abundant quantity; in the previous study this was apparently not detected in the IGF-I-bound fraction with the PEG precipitation and Western ligand blot assays. In the current study, IGF-II affinity purification of IGFBPs produced by PC-3 cells, followed by C8 HPLC reverse-phase chromatography using a shallow acetonitrile gradient, produced two major protein peaks. N-terminal amino acid sequence of peak 1 was identical to that of IGFBP-6 while that of peak 2 was identical to that of IGFBP-4. Characterization of purified IGFBP-6 from PC-3 cells revealed properties which are distinct from other IGFBPs. PEG did not precipitate the complex of 125I-IGF-II/IGFBP-6 while it precipitated the complexes between 125I-IGF-II and other IGFBPs. Indeed, IGFBP-6 decreased the amount of 125I-IGF-II tracer in the PEG precipitate in a dose-dependent manner. Also, the binding of IGFBP-6 with 125I-IGF-II was poor in Western ligand blots compared with other IGFBPs. In studies on IGFBP-6 actions, IGFBP-6 completely inhibited IGF-II-induced [3H]thymidine incorporation in MC3T3-E1 mouse osteoblast cells while it had only minimal inhibitory effects on IGF-I-induced [3H]thymidine incorporation. This differential effect is associated with the fact that IGFBP-6 has greater affinity for IGF-II than IGF-I. The results of this study indicated that (1) Western ligand blotting is not sensitive for identification of IGFBP-6, (2) the unique behavior of IGFBP-6 in the PEG assay system necessitates the use of charcoal adsorption procedure for IGFBP-6 activity detection and (3) PC-3 cells should provide a useful model system for studying regulation of IGFBP-6 expression and the role of IGFBP-6 in modulating IGF actions.
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PMID:Insulin-like growth factor-binding protein-6 produced by human PC-3 prostate cancer cells: isolation, characterization and its biological action. 870 41

The correlative effects of taxol on the reduction of circulating PC-3 ML human prostatic tumor cells and bone metastasis have been examined in SCID mice. Normally, following injection of 2 x 10(5) cells i.v., the circulating levels in peripheral blood drop by about 50 and 100%, after 8 and 24 h, respectively. In contrast, in taxol-treated mice (40-60 mg/m2/injection given 0, 3, 7 and 23 h following injection of the cells) the numbers of circulating human prostatic PC-3 ML tumor cells were reduced by 100% at 8 h. In similar experiments were mice were injected with taxol 2 h prior to injecting the cells, dosages of 40 and 60 mg/m2/injection reduced circulating tumor cells about 91 and 100%, respectively, by 8 h. Alternatively, if PC-3 Ml cells were pretreated with taxol (0.5 and 1.0 microM for 8 and 24 h) prior to injection, tumor cell clearance by 7 h was also significantly increased (80-100%). Correlative studies showed that the incidence of bone metastases (observed after 40 days) was reduced significantly (a) in mice treated with 40 and 60 mg/m2/injection (i.e. from 73-80% in controls to 15-0% in treated mice) and (b) in mice injected with PC-3 ML cells pre-exposed to 0.5-1.0 microM taxol for 7 h. Immunofluorescence studies with tubulin antibodies showed that the microtubules were disrupted in cells exposed to taxol in vivo and in vitro under conditions that significantly increased cellular clearance from the blood. Taken together, the data suggests that taxol at nontoxic dosages (to mice) can prevent metastases by directly reducing the circulating levels of tumor cells.
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PMID:Taxol reduces circulating tumor cells to prevent bone metastases in SCID mice. 876 98


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