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)

Several laboratories have reported on the apoptotic potentials of human prostate cancer (PC) cell lines in response to crosslinking of Fas (CD95/APO-1) with agonistic anti-Fas antibodies. We have re-evaluated the apoptotic potentials of seven human PC cell lines using the natural Fas ligand (FasL) in place of agonistic antibody. First, PC cell lines were tested in a standard cytotoxicity assay with a transfected cell line that stably expresses human FasL. Next, we developed an adenoviral expression system employing 293 cells that stably express crmA, a poxvirus inhibitor of apoptosis, to analyze the effects of FasL when expressed internally by the PC cell lines. Our data suggest that the apoptotic potentials of these cell lines were greatly underestimated in previous studies utilizing agonistic anti-Fas antibodies. Lastly, adenoviral-mediated expression of FasL prevented growth and induced regression of two human PC cell lines in immunodeficient mice. These preliminary in vivo results suggest a potential use for adenovirus encoding FasL as a gene therapy for PC.
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PMID:Adenovirus-mediated expression of Fas ligand induces apoptosis of human prostate cancer cells. 1020 May 64

Fas (Apo-1/CD95) is a cell-surface receptor involved in cell death signaling through binding of Fas ligand. Mutations of the Fas gene might be involved in proliferative diseases of the prostate by prolongation of programmed cell death of prostatic epithelial cells. Using the laser capture microdissection method, Fas gene mutations were examined on genomic DNA extracted from lesions with high-grade prostatic intraepithelial neoplasia (HGPIN), a possible precursor of prostatic cancer (PCA), and from PCA. A total of 193 lesions, 111 with HGPIN, 55 with PCA, and 27 benign glands, were microdissected from 27 patients with PCA. Polymerase chain reaction-amplified products were directly sequenced. Loss of heterozygosity (LOH) was examined at four sites of known polymorphisms. Fas gene mutations were detected in HGPIN: 4 of 27 (14.8%) cases or 4 of 111 (3.6%) lesions. All were point mutations: three missense and one nonsense in the death domain. Benign proliferative glands adjoining HGPIN and/or PCA, and PCA never showed mutations. LOH was found in 31.3% of PCA and 25% of HGPIN lesions, but was never found in benign glands. Exclusive occurrence of Fas mutations in HGPIN might underlie the development of these lesions. Occasional findings of LOH in HGPIN and PCA suggested that genetic instability might occur during the early phase of prostatic carcinogenesis.
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PMID:Fas gene mutations in prostatic intraepithelial neoplasia and concurrent carcinoma: analysis of laser capture microdissected specimens. 1131 Aug 21

Fas-associated death domain (FADD) plays an important role as an adapter molecule in Fas (CD95/APO-1)-mediated apoptosis and contributes to anticancer drug-induced cytotoxicity. We treated three human prostate cancer cell lines with etoposide, a toposiomerase II inhibitor with activity against various tumors including prostate cancer. We found that the overexpression of FADD sensitizes etoposide-induced apoptosis through a rapid activation of c-Jun NH(2)-terminal kinase (JNK) and, subsequently, of caspase 3. In addition, phosphorylation of FADD at serine 194 coincided with this sensitization. Treatment with the caspase 3 inhibitor, N-acetyl-Asp-Glu-Val-Asp-aldehyde (DEVD-CHO), or overexpression of either mitogen-activated protein kinase kinase (MKK) 7 or Bcl-xL canceled FADD-mediated sensitization to etoposide-induced apoptosis. Moreover, treatment with the caspase 8 inhibitor, benzyloxy-carbonyl-Val-Ala-Asp-fluoromethylketone (z-IETD-fmk), or overexpression of viral FLICE/caspase-8-inhibitory protein (FLIP) from equine herpesvirus type 2 E8 also had an inhibitory effect, supporting a major involvement of a caspase 8-dependent mitochondrial pathway. Interestingly, FADD was phosphorylated, and etoposide-induced JNK/caspase activation and apoptosis were enhanced in the cells arrested at G2/M transition, but not in those overexpressing mutant FADD, in which 194 serine was replaced by alanine. Our results demonstrate that phosphorylated FADD-dependent activation of the JNK/caspase pathway plays a pivotal role in sensitization to etoposide-induced apoptosis in prostate cancer cells.
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PMID:Phosphorylation of Fas-associated death domain contributes to enhancement of etoposide-induced apoptosis in prostate cancer cells. 1241 47

In the majority of aggressive tumorigenic prostate cancer cells, the transcription factor Egr1 is overexpressed. We provide new insights of Egr1 involvement in proliferation and survival of TRAMP C2 prostate cancer cells by the identification of several new target genes controlling growth, cell cycle progression, and apoptosis such as cyclin D2, P19ink4d, and Fas. Egr1 regulation of these genes, identified by Affymetrix microarray, was confirmed by real-time PCR, immunoblot, and chromatin immunoprecipitation assays. Furthermore we also showed that Egr1 is responsible for cyclin D2 overexpression in tumorigenic DU145 human prostate cells. The regulation of these genes by Egr1 was demonstrated using Egr1 antisense oligonucleotides that further implicated Egr1 in resistance to apoptotic signals. One mechanism was illustrated by the ability of Egr1 to inhibit CD95 (Fas/Apo) expression, leading to insensitivity to FasL. The results provide a mechanistic basis for the oncogenic role of Egr1 in TRAMP C2 prostate cancer cells.
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PMID:Egr1 promotes growth and survival of prostate cancer cells. Identification of novel Egr1 target genes. 1255 66

To accomplish efficient nonviral gene therapy against prostate cancer (PC), Epstein-Barr virus (EBV)-based plasmid vectors containing EBNA1 gene and oriP were employed and combined with a cationic polymer or cationic lipid. When EBV-plasmid/poly-amidoamine dendrimer complex was injected into PC-3-derived tumors established in severe combined immunodeficiency mice, a considerable expression of marker gene was obtained in the tumors, and the expression level was more than eight-fold higher than that achieved by conventional plasmid vector/dendrimer. Since most PC cells express the apoptotic signal molecule Fas (Apo-1/CD95) on their surface, Fas ligand (FasL) gene was transferred into PC cells to kill the tumor cells. In vitro transfection with pGEG.FasL (an EBV-plasmid with the FasL gene) significantly reduced the viability of PC cells, which subsequently underwent apoptosis. Intratumoral injections of pGEG.FasL into PC induced significant growth suppression of the xenograft tumors, in which typical characteristics of apoptosis were demonstrated by TUNEL staining and electron microscopic observations. When pGEG.FasL transfer was accompanied by systemic administrations of cisplatin, the tumors were inhibited even more remarkably, leading to prolonged survival of the animals. FasL gene transfection by means of EBV-based plasmid/cationic macromolecule complexes may provide a practical therapeutic strategy against PC.
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PMID:Nonviral genetic transfer of Fas ligand induced significant growth suppression and apoptotic tumor cell death in prostate cancer in vivo. 1260 98

Single-agent docetaxel (Taxotere) treatment has recently demonstrated promising clinical activity in patients with advanced hormone-refractory prostate cancer. Taxanes were recently found to upregulate the tumoral activity of thymidine phosphorylase (TP), a key cellular enzyme [transformation of 5'-deoxy-5-fluorouridine (5'-DFUR) into 5-fluorouracil] in the activation cascade of capecitabine (Xeloda). We tested (cytotoxic effects and molecular mechanisms) the Taxotere-5'-DFUR combination on hormone-refractory prostate cancer cell lines (DU145 and PC3). Cells were exposed to Taxotere and/or 5'-DFUR in three different sequences: Taxotere was given alone for 48 h, then 5'-DFUR was added for 48 h; Taxotere and 5'-DFUR together during 96 h or 5'-DFUR was given alone for 48 h then Taxotere was added for 48 h. The drug sequence Taxotere applied first followed by 5'-DFUR led to synergistic cytotoxic effects on both cell lines; the other sequences resulted in simple additivity. Taxotere did not modify TP activity while it decreased thymidylate synthase activity. There was an increase in CD95 cellular membrane levels following exposure to Taxotere-5'-DFUR, which is in agreement with the supra-additive cytotoxic combination. This observation may serve as a preclinical rationale for a next step testing the Taxotere-capecitabine combination at the clinical level in prostate cancer patients.
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PMID:Taxotere-5'-deoxy-5-fluorouridine combination on hormone-refractory human prostate cancer cells. 1571 Nov 83

Quinazoline-based alpha1-adrenoceptor antagonists such as doxazosin and terazosin have been previously shown to induce apoptosis in prostate cancer cells via an alpha1-adrenoceptor-independent pathway, involving activation of transforming growth factor-beta1 (TGF-beta1) signaling. In this study, the molecular events initiating this apoptotic effect were further investigated in vitro using the human androgen-independent prostate cancer cells PC-3 and the human benign prostate epithelial cells BPH-1. Quantitative microarray assays were done in PC-3 and BPH-1 cells after treatment with doxazosin (25 micromol/L, 6 and 24 hours) to identify the early gene changes. Transient changes in the expression of several apoptosis regulators were identified, including up-regulation of Bax and Fas/CD95 and down-regulation of Bcl-xL and TRAMP/Apo3. Moreover, there were significant changes in the expression pattern of signaling components of the extracellular matrix such as integrins alpha2, alphaV, beta1, and beta8. Western blot analysis revealed activation of caspase-8 and caspase-3 within the first 6 to 12 hours of treatment with doxazosin in both PC-3 and BPH-1 cells. Doxazosin-induced apoptosis was blocked by specific caspase-8 inhibitors, supporting the functional involvement of caspase-8 in doxazosin-induced apoptosis. The effect of doxazosin on recruitment of Fas-associated death domain (FADD) and procaspase-8 to the Fas receptor was examined via analysis of death-inducing signaling complex formation. Doxazosin increased FADD recruitment and subsequent caspase-8 activation, implicating Fas-mediated apoptosis as the underlying mechanism of the effect of doxazosin in prostate cells. These results show that doxazosin exerts its apoptotic effects against benign and malignant prostate cells via a death receptor-mediated mechanism with a potential integrin contribution towards cell survival outcomes.
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PMID:Doxazosin induces apoptosis of benign and malignant prostate cells via a death receptor-mediated pathway. 1639 62

There is an increasing awareness of the therapeutic potential for combining immune-based therapies with chemotherapy in the treatment of malignant diseases, but few published studies evaluate possible cytotoxic synergies between chemotherapy and cytotoxic immune cells. Human V alpha 24+/V beta 11+ NKT cells are being evaluated for use in cell-based immunotherapy of malignancy because of their immune regulatory functions and potent cytotoxic potential. In this study, we evaluated the cytotoxicity of combinations of chemotherapy and NKT cells to determine whether there is a potential to combine these treatment modalities for human cancer therapy. The cytotoxicity of NKT cells was tested against solid-tumor derived cell lines NCI-H358, DLD-1, HT-29, DU-145, TSU-Pr1 and MDA-MB231, with or without prior treatment of these target cells, with a range of chemotherapy agents. Low concentrations of chemotherapeutic agents led to sensitization of cell lines to NKT-mediated cytotoxicity, with the greatest effect being observed for prostate cancer cells. Synergistic cytotoxicity occurred in an NKT cell in a dose-dependent manner. Chemotherapy agents induced upregulation of cell surface TRAIL-R2 (DR5) and Fas (CD95) expression, increasing the capacity for NKT cells to recognize and kill via TRAIL- and FasL-mediated pathways. We conclude that administration of cytotoxic immune cells after chemotherapy may increase antitumor activities in comparison with the use of either treatment alone.
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PMID:Chemotherapy pretreatment sensitizes solid tumor-derived cell lines to V alpha 24+ NKT cell-mediated cytotoxicity. 1664 79

Doxazosin triggers apoptosis via an imprecisely defined receptor mechanism that is related to tumor necrosis factor receptors (TNFRs). The aim of this study was to determine CD95, TNFR-1, TNFR-2, CD40 expression in primary prostate epithelial cultures incubated with doxazosin. Epithelial cultures were cultivated from 10 benign prostate hyperplasia patients. The cells were incubated with 20, 50 and 80 microM of doxazosin. Apoptosis was confirmed by fluorescence microscopy and flow cytometry. The cells were analyzed for expression of FAS, CD40, TNFR-1 and TNFR-2 by flow cytometry. Early apoptotic cells were present in all groups. A positive correlation was noticed between doxazosin dose and TNFR-1-, -2-positive cells. A decrease of CD40-positive cell population was observed in the lowest concentration. A decrease of mean fluorescence intensity signal of CD40 and CD95 was observed in the lowest concentration. Doxazosin-triggered apoptosis was dose-independent. The initiation of apoptosis was a result of receptors 'crosstalk' rather than a single receptor pathway activation. TNF receptor self-assembly process should be checked as a potential mechanism leading to apoptosis after doxazosin treatment.
Prostate Cancer Prostatic Dis 2008
PMID:The influence of alpha1-antagonist on the expression pattern of TNF receptor family in primary culture of prostate epithelial cells from BPH patients. 1753 95

To convert the concept already successful in mice into clinical practice and commercialize it, a human anti-CD95-antibody must be produced. In a second step experiments must be performed on various normal healthy cells and tissues to determine whether these human anti-CD95-antibodies administered in very low doses have any effect on human cells (particularly hepatocytes) or at least cause only minimal side effects. If these studies yield positive results, then clinical trials can be conducted in which increasing doses are given to exclude an acute hepatotoxic effect and then the effect exerted by the antibody in combination with irradiation on tumor growth can be investigated.The advantage of this concept lies in the fact that systemic stimulus (low doses of anti-CD95-antibodies) is highly intensified by local radiotherapy and only then initiates cell death. Since the anti-CD95-antibodies trigger apoptosis primarily in tumor endothelia, this approach could be employed not only for prostate cancer and melanomas, which have already been tested, but also for many other tumors.
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PMID:[Proapoptotic antibodies as new therapeutic agents for tumor treatment]. 1759 83


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