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)

Inactivation of tumour suppressor gene function is a critical step in the development of human neoplasia. The Rb and CDKN2 tumour suppressor genes are inactivated in many tumour types, including the late stages of prostate cancer, and appear to function in the same suppressor pathway. p53, another major tumour suppressor is also mutated in a subset of advanced-stage prostate carcinomas. E-cadherin and other cell adhesion genes, which have been characterized as suppressors of the metastatic phenotype, are inactivated or downregulated during progression to advanced prostate cancer and have been associated with poor clinical outcome. The early genetic events involved a prostatic neoplasia are poorly understood, but loss of as yet undiscovered tumour suppressor genes may play a role in the initiation of this disease.
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PMID:Tumour suppressor genes in prostate cancer. 929 77

We performed a detailed and comprehensive study of the involvement of tumor suppressor genes in human prostate cancer. We utilized primers flanking either the restriction fragment length polymorphism (RFLP) or variable number of tandem repeat [VNTR; microsatellite or simple repeat site (SRS)] polymorphic sites to polymerase chain reaction (PCR) amplify the genomic DNA and detect loss of heterozygosity of the target genes. Quantitative reverse transcription (RT)-PCR was performed to measure the mRNA expression levels and PCR/single strand conformational polymorphism (SSCP) and DNA sequencing carried out to detect mutation of the tumor suppressor genes. We found that multiple tumor suppressor genes (e.g., p53, DCC, APC, MCC, BRCA1, and WAF1/CIP1) were inactivated at different frequencies via various mechanisms [e.g., loss of heterozygosity (LOH), loss of expression (LOE), mutation, and inactivation by cellular binding protein]. Several important and novel findings are as following: LOH and LOE of the DCC gene, LOH, LOE, and possible mutation of the APC/MCC genes, LOH of the BRCA1 locus, and mutation of the WAF1/CIP1 gene. For p53 tumor suppressor gene alone, multiple inactivation mechanisms (i.e., LOH, LOE, mutation, and amplification of the cellular inactivating protein MDM2) were identified. A possible involvement of genomic instability or mutator phenotype in human prostate cancer was investigated by microsatellite typing using PCR. A high frequency of microsatellite instability was detected and the microsatellite instability found to correlate with advanced stage and poor differentiation of prostate cancer, suggesting that genes functioning in DNA mismatch repair or general stabilization of the genome may be involved in prostate cancer. The results obtained in this study suggested that multiple tumor suppressor genes (both known and unknown genes) may share the role in prostate cancer; a pattern which has been found in a number of human malignancies such as cancers of the esophagus, colon and breast. In fact, we performed deletion studies aimed at localizing potential tumor suppressor loci on various chromosomal regions. A number of chromosomal regions (i.e., 6p12-24 and 17q21) were found to potentially harbor unidentified tumor suppressor genes. Detailed deletion mapping has localized the potential tumor suppressor loci to a < 2 Mb region centromeric to the BRCA1 gene on chromosome 17q. In addition, we identified a number of novel mechanisms of tumor suppressor gene inactivation, in prostate cancer such as loss of mRNA expression of the DCC, APC, MCC and p53 gene, and mutator phenotype. And for the very first time, we identified somatic mutations of the WAF1/CIP1 gene in primary human malignancy-human prostate cancer. This finding provides the first evidence in primary tumor that the WAF1/CIP1 gene may be a tumor suppressor gene and may be involved in prostate cancer. We identified 12-lipoxygenase (12-LOX) as a potential prognostic marker for human prostate cancer. mRNA expression levels of the 12-LOX gene was measured by quantitative reverse transcription-polymerase chain reaction (RT-PCR) and semi-quantitative in situ hybridization (ISH) in 122 pairs of matched normal and tumor tissues from prostate cancer patients. We found that 12-LOX expression levels were elevated in approximately half of the patients analyzed and the 12-LOX elevation correlates with advanced stage, poor differentiation, and surgical margin positivity. Our data suggest that 12-LOX may serve as a correlative marker for a more aggressive phenotype of prostate cancer and therefore for poor prognosis. We are currently refining our assays for possible clinical applicability. Since not all patients with loss of expression of the DCC gene showed LOH of the DCC locus, there must be other mechanism(s) responsible for loss of expression of the DCC gene. When we analyzed the relationship between DCC loss of expression and 12-LOX elevation in prostate cancer pati
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PMID:Involvement of the multiple tumor suppressor genes and 12-lipoxygenase in human prostate cancer. Therapeutic implications. 932 30

We previously developed an in vivo mouse prostate reconstitution (MPR) model of metastatic prostate cancer using p53 'knockout' mouse urogenital sinus tissue for retroviral transduction of ras and myc oncogenes (Thompson et al., Oncogene, 10, 869, 1995). We further demonstrated contrasting responses to transforming growth factor beta-1 (TGF-beta1) in three matched pairs of early passage cell lines derived from primary prostate tumors and lung metastases generated by this model system (Sehgal et al., Cancer Res, 56, 3359, 1996). In this study we tested these cell lines for growth potential in subcutaneous and orthotopic (dorso-lateral prostate) locations and metastatic activities in both spontaneous and experimental assays. Subcutaneous and orthotopic tumors produced by cell lines derived from metastatic lesions tended to grow less rapidly but demonstrated greater spontaneous metastatic potential than the cell lines derived from primary tumors. In contrast all cell lines produced lung colonies in an experimental metastasis assay (tail vein inoculation) with the primary tumor-derived cell lines yielding higher activities in two of three matched pair analyses. The ability of all cell lines to produce lung metastases in the experimental assay, while only the metastasis-derived cell lines retain the ability to initiate and complete the entire metastatic pathway in the spontaneous assay, suggests that intravasation may be the rate-limiting step in metastasis in this model system.
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PMID:Spontaneous but not experimental metastatic activities differentiate primary tumor-derived vs metastasis-derived mouse prostate cancer cell lines. 934 47

Luteinizing Hormone Releasing Hormone (LHRH) agonists exert both "in vitro" and "in vivo" a direct inhibitory action on the growth of both androgen-dependent (LNCaP) and androgen-independent (DU 145) human prostatic cancer cell lines. The present experiments have been performed to investigate the mechanisms involved in this direct antiproliferative action of LHRH agonists. In particular, the aim was to study whether these compounds might exert their antiproliferative effect by interfering with the stimulatory action of epidermal growth factor (EGF) both "in vitro" and "in vivo". To this purpose, the effects of LHRH agonist, Zoladex (LHRH-A), on the mitogenic action of EGF, on EGF-activated intracellular signaling mechanisms (tyrosine phosphorylation of EGF receptor and c-fos proto-oncogene expression), and on the concentration of EGF receptors have been evaluated in both LNCaP and DU 145 cells. The results of these "in vitro" studies show that in LNCaP cells LHRH-A counteracts the mitogenic action of EGF, abrogates the EGF-induced c-fos expression and reduces the concentration of EGF-binding sites, without modifying the EGF induced tyrosine phosphorylation. In DU 145 cells, LHRH-A antagonizes the proliferative action of EGF, inhibits tyrosine phosphorylation of EGF receptor induced by EGF and significantly reduces the number of EGF binding sites, without altering the stimulation of c-fos expression induced by EGF. For the "in vivo" experiments, male nude mice were s.c. injected in the flank with DU 145 cells and treated for 14 days with LHRH-A (100 micrograms/days). At the end of the treatment, the concentration of EGF receptors on membrane preparations as well as on tumor volume were found to be significantly lower in LHRH-A treated animals than in control mice. The mitotic index and the expression of the proliferation-associated antigen Ki67 were found similar in control as well as in treated animals. In addition no modification of apoptotic index (expression of p53) was observed. These data suggest that LHRH agonists may inhibit the proliferation of the tumor cells by interfering with the stimulatory actions of EGF.
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PMID:Effects of LHRH agonists on the growth of human prostatic tumor cells: "in vitro" and "in vivo" studies. 939 87

The tumor suppressor protein p53 is a pivotal regulator of apoptosis, and prostate cancer cells that lack p53 protein are moderately resistant to apoptotic death by ionizing radiation. Genes encoding the transcription factor early growth response-1 (EGR-1) and cytokine tumor necrosis factor-alpha (TNF-alpha) were induced upon irradiation of prostate cancer cells, and inhibition of EGR-1 function resulted in abrogation of both TNF-alpha induction and apoptosis. Induction of the TNF-alpha gene by ionizing radiation and EGR-1 was mediated via a GC-rich EGR-1-binding motif in the TNF-alpha promoter. Because TNF-alpha induces apoptosis in prostate cancer cells, these findings suggest that, in the absence of p53, ionizing radiation-inducible apoptosis is mediated by EGR-1 via TNF-alpha transactivation.
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PMID:Ionizing radiation-inducible apoptosis in the absence of p53 linked to transcription factor EGR-1. 940 88

The widespread use of prostate-specific antigen (PSA) has revealed that radiation therapy cures adenocarcinoma of the prostate less frequently than previously believed. Biologic factors (such as the complex nature of this disease) and technical factors (geographic miss, inadequate dose to the tumor volume) affect the ability of radiation to effectively treat all patients with prostate cancer. To improve treatment outcome, patients with virulent forms of the disease must be identified. The use of prognostic markers (PSA, prostate-specific membrane antigen, prostate-specific antigen doubling time) and genetic markers (12 lipoxygenase, p53, bcl-2, ploidy) may aid in the development of treatments for these patients. Technical modifications have been made to increase the total dose delivered to the prostate and the accuracy of dose delivery. Brachytherapy, proton therapy and conformal radiation therapy have been used to increase the relative integral dose. Improved prostate targeting may be achieved with the use of fiducial markers, on-line portal imaging, and endorectal magnetic resonance imaging. High linear energy transfer radiation, radiosensitizers and altered fractionation have been used in an attempt to increase the biologic equivalent dose to the tumor. Lastly, hormonal therapy and chemotherapy have been shown to decrease tumor burden and improve local control. All of these methods may improve outcome in patients with adenocarcinoma of the prostate. However, further work must be completed to translate these methods into standards of care.
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PMID:A rational approach to the treatment of prostate cancer with radiation therapy: lessons for the future. 942 69

While prostate cancer is the most common malignant visceral neoplasm of men, its etiology remains largely unknown and its clinical course unpredictable. Molecular genetics of prostate cancer has become a fruitful area of investigation and might provide clues to understanding these phenomena. Mutation of the TP53 tumor suppressor gene (encoding the p53 protein) has been commonly reported as a critical event in human carcinogenesis, but recent findings in prostate cancer research call into question the correlation between TP53 mutation and prognosis for patients with this tumor. Whole-mount analysis has begun to address the histologic significance of the focal evolution of TP53 mutation in a pre-existing cancer and to reveal its role throughout the process of tumor progression. This model might also apply to other tumors.
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PMID:Molecular heterogeneity in prostate cancer: can TP53 mutation unravel tumorigenesis? 943 Jul 82

Our laboratory has developed two cellular models of human prostate cancer progression. The LNCaP prostate cancer progression model is based upon the well-known cellular interaction between human prostate or bone stromal cells and LNCaP cells in vivo. The marginally tumorigenic LNCaP cells acquired tumorigenic and metastatic potential upon cellular interaction with either prostate or bone fibroblasts. A subline termed C4-2 was observed to grow readily in castrated animals and acquired metastatic potential spreading from the primary tumor site to the lymph node, the seminal vesicles, and the axial skeleton, resulting in an intense osteoblastic reaction. The second model is ARCaP, where prostate cancer cells derived from the ascites fluid of a man with metastatic disease exhibited an Androgen- and estrogen-Repressed Prostate Cancer cell growth and tumor formation in either a hormone-deficient or a castrated environment. However, the growth of either the tumor cells in vitro or the tumors in vivo was suppressed by both estrogen and androgen. While the tumor cells expressed low levels of androgen receptor and prostate-specific antigen (PSA), they were highly metastatic when inoculated orthotopically. Distant metastases to a number of organs were detected, including the liver, lung, kidney, and bone. We have employed a human prostate cancer progression model as a system to study the efficacy of gene therapy. Results of the study show that whereas universal promoters, such as Cytomegalovirus (CMV) and Rous Sarcoma Virus (RSV) promoter-driven tumor suppressors (e.g. p53, p21, and p16), were effective in inhibiting prostate tumor growth, the advantages of driving the expression of therapeutic toxic genes using a tissue-specific promoter prostate-specific antigen (PSA) and a tumor--but not tissue-specific promoter, osteocalcin (OC), are preferred. In the case of the PSA promoter, we can achieve cell-kill in PSA-producing human prostate cancer cells. To circumvent the supporting role of bone stroma for prostate cancer epithelial growth, we have recently developed a novel concept where the expression of therapeutic toxic genes is driven by a tumor--but not a tissue-specific OC promoter. Osteocalcin-thymidine kinase (OC-TK) was found to efficiently eradicate the growth of osteosarcoma, prostate, and brain tumors both in vitro and in vivo. We observed that androgen-independent human prostate cancer cells lines expressed OC-TK at higher levels than androgen-dependent human prostate cancer cell lines. We have obtained data to suggest that Ad-OC-TK plus a pro-drug acyclovir (ACV) may be used as an effective therapy to treat prostate cancer bone metastasis in models where the growth of androgen-independent PC-3 and C4-2 tumors in the bone has occurred.
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PMID:Human prostate cancer progression models and therapeutic intervention. 943 28

Perineal needle tract seeding of prostate cancer is an unusual complication of perineal prostate biopsy. We report a case with the longest known interval from biopsy to perineal recurrence--14 years. The prostate-specific antigen did not become detectable until 12 years after biopsy and no other metastases were apparent, suggesting that the patient's perineal disease was an isolated recurrence. Immunohistochemical staining of the perineal recurrence and the original biopsy and prostate for the p53 tumor suppressor gene and bcl-2 oncogene proteins revealed rare/absent p53 expression but marked increased bcl-2 expression. This unusual molecular pedigree may help to explain this rare clinical scenario.
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PMID:Perineal seeding of prostate cancer as the only evidence of clinical recurrence 14 years after needle biopsy and radical prostatectomy: molecular correlation. 945 12

New human prostate cell lines were developed from prostatic carcinoma (BRF-41T) and BPH (BRF-55T). Primary cultures were initiated from cellular outgrowths of explanted tissues. A serum-free medium, BRFF-HPC1, was developed for growing human prostatic cancer cells. Cell strains were immortalized with pRSV-T plasmid to generate permanent cell lines that exhibited an epithelial morphology. Both cell lines expressed the epithelial cell markers, cytokeratins 8 and 18 as well as the prostatic marker, PSA, and the androgen receptor gene. They possess the H-ras, K-ras, and p53 genes. We hope that these new human prostatic cell lines will be useful as in vitro models for cancer research.
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PMID:Establishment and characterization of immortalized human cell lines from prostatic carcinoma and benign prostatic hyperplasia. 945 47


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