Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P43146 (tumour suppressor)
 5,935 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

As yet, few molecular markers are available that are likely to be useful in predicting the metastatic potential of prostate cancer cancer cells. The need for such "progression markers" is indicated by the expectation that more localized cancers (ie stage A-2, B-1,2) will be clinically diagnosed in the near future, owing to improvements in diagnostic techniques (eg transrectal ultrasound) and the screening of population groups at risk (males over 50 years old). Few model systems are available for such studies. Animal models are unsuitable for the isolation of monoclonal antibodies that detect epitopes associated with the progression of prostate cancer. Since few cell lines are available, an approach using primary cancer tissue should be undertaken. For the differential hybridization approach described here, the choice of species presents no difficulty, since many DNA sequences are conserved between species. However, no model system fully represents the human situation. Hence, differential hybridization studies using primary prostate cancer tissue need to be considered. Moreover, the group of genes/proteins with potential relevance for cancer progression (eg oncogenes, tumour suppressor genes, genes encoding cell adhesion molecules or growth factors) has not been studied extensively in prostate cancer. Because of the intrinsic heterogeneity of prostate tumours, the use of pathologically defined tissue sections is imperative for a reliable study. This could be achieved either by in situ techniques (whereby tissue morphology is conserved) or by step sectioning. The difficulties associated with the small amount of material obtained from such sections can be overcome by the use of techniques based on the polymerase chain reaction. Taking these considerations into account, a systematic screening of prostate cancer with probes representing the above mentioned genes should be undertaken.
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PMID:Molecular methods for predicting the metastatic potential of prostate cancer. 172 88

The growth of human prostate cancer and its relationship to the surrounding stroma are controlled by complex mechanisms that are incompletely understood. Clearly, peptide growth factors appear to have crucial roles in these processes. One of these factors, TGF-beta, and its family members are notable for their wide spectrum of biological effects. In terms of growth, TGF-beta inhibits the growth of prostate cancer cells in a cytostatic fashion while stimulating the growth of critical stromal cells, such as fibroblasts. Since the inhibitory effects of TGF-beta on prostate cancer cells appear to diminish as the process of transformation progresses towards less differentiated states, the net effect on prostate tumour growth may be positive. Recent evidence suggests that the inhibitory effects of TGF-beta on growth, at least, might be mediated through the RB tumour suppressor gene product and the proto-oncogene c-myc. Beyond its direct growth effects, TGF-beta also alters the response of prostate cancer cells to positive mitogenic factors, such as members of the EGF and FGF families, suggesting that growth control is a delicate balance between positive and negative influences. Non-mitogenic responses to TGF-beta by prostate cancer cells, the immune system, the stroma and the vascular system provide evidence that TGF-beta might also be important in the processes of carcinogenesis, tumour establishment and metastases. In addition, TGF-beta appears to influence metabolic pathways important to drug metabolism and steroidogenesis. In vivo, limited evidence suggests that TGF-beta can alter the growth and differentiation of some tumour types but appears to be very toxic when administered in high doses. A better understanding of the response of prostate cancer cells to members of the TGF-beta family may open new avenues of treating and controlling this disease.
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PMID:Response of prostate cancer cells to peptide growth factors: transforming growth factor-beta. 184 49

We have detected allelic loss in a majority of prostate cancers analysed. These losses have been detected on several chromosomes known to harbour tumour suppressor genes important in the development of other tumour types. Elevated rates of loss of heterozygosity on chromosome 16q and 10q suggest that tumour suppressor genes important in the pathogenesis of prostate cancer may be present on these chromosomes. Conversely, determination of the frequency of ras gene mutations in prostate cancer tissue suggests that these genetic alterations play a minor part in both the initiation and progression of this disease in humans.
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PMID:Genetic changes associated with prostate cancer in humans. 184 50

A number of genetic changes have been documented in prostate cancer, ranging from allelic loss to point mutations and changes in DNA methylation patterns (summarized in Fig. 1). The most consistent changes seen are those of allelic loss events, with the majority of tumours examined showing loss of alleles from at least one chromosomal arm. The short arm of chromosome 8, followed by the long arm of chromosome 16, seem to be the most frequent regions of loss, suggesting the presence of novel tumour suppressor genes. Deletions of one copy of the RB and TP53 genes are less frequent as are mutations of the TP53 gene, and accumulating evidence suggests the presence of an additional tumour suppressor gene on chromosome 17p, which is frequently inactivated in prostate cancer. Alterations in the E-cadherin/alpha catenin mediated cell-cell adhesion mechanism appear to be present in almost half of all prostate cancers and may be critical to the acquisition of metastatic potential of aggressive prostate cancers. Finally, altered DNA methylation patterns have been found in the majority of prostate cancers examined, suggesting widespread alterations in methylation modulated gene expression. The presence of multiple changes in these tumours is consistent with the multistep nature of the transformation process. Finally, efforts to identify prostate cancer susceptibility loci are under way, which may elucidate critical early events in prostatic carcinogenesis.
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PMID:Molecular biology of prostate cancer progression. 762 57

Patients with prostate cancer are at a significant risk of either having a preceding tumour or developing a second malignancy. The precise mechanism by which second cancers develop is not clear but may be the result of exposure to a shared mutagen, abnormalities in oncogene activation or the aberrant expression of tumour suppressor genes. In the recent past, case reports and tumour registry studies on the risk of second cancer development have been important and have alerted the clinician that careful surveillance in this group of patients is required. More prospective hospital based studies are required to delineate the true risk of second malignancies in association with prostate cancer.
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PMID:Multiple primary cancers in association with prostate cancer. 762 62

The Mxi1 protein negatively regulates Myc oncoprotein activity and thus potentially serves a tumour suppressor function. MXI1 maps to chromosome 10q24-q25, a region that is deleted in some cases of prostate cancer. We have detected mutations in the retained MXI1 alleles in four primary prostate tumours with 10q24-q25 deletions. Two tumours contained inactivating mutations, whereas two others contained the identical missense mutation. Fluorescence in situ hybridization also demonstrated loss of one MXI1 allele in an additional tumour lacking chromosome 10 abnormalities. MXI1 thus displays allelic loss and mutation in some cases of prostate cancer that may contribute to the pathogenesis or neoplastic evolution of this common malignancy.
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PMID:Mutation of the MXI1 gene in prostate cancer. 777 87

Prostate cancer is one of the leading causes of cancer deaths in the Western world and current therapies are of limited efficacy in advanced disease. Both ex vivo and in vivo gene therapy strategies offer exciting new possible approaches to the management of this disease. Ex vivo gene therapy involving interleukin-2 or granulocyte-macrophage colony-stimulating factor transduced whole tumour cell vaccines has shown great promise in animal models. The feasibility of in vivo corrective gene therapy involving the replacement of mutant tumour suppressor genes, antisense strategies and the insertion of suicide genes has been demonstrated in preclinical models. Several of these therapies are now entering phase I/II studies in patients with prostate cancer.
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PMID:Gene therapy for prostate cancer. 890 97

Cowden disease (CD) is an autosomal dominant cancer predisposition syndrome associated with an elevated risk for tumours of the breast, thyroid and skin. Lhermitte-Duclos disease (LDD) cosegregates with a subset of CD families and is associated with macrocephaly, ataxia and dysplastic cerebellar gangliocytomatosis. The common feature of these diseases is a predisposition to hamartomas, benign tumours containing differentiated but disorganized cells indigenous to the tissue of origin. Linkage analysis has determined that a single locus within chromosome 10q23 is likely to be responsible for both of these diseases. A candidate tumour suppressor gene (PTEN) within this region is mutated in sporadic brain, breast and prostate cancer. Another group has independently isolated the same gene, termed MMAC1, and also found somatic mutations throughout the gene in advanced sporadic cancers. Mutational analysis of PTEN in CD kindreds has identified germline mutations in four of five families. We found nonsense and missense mutations that are predicted to disrupt the protein tyrosine/dual-specificity phosphatase domain of this gene. Thus, PTEN appears to behave as a tumour suppressor gene in the germline. Our data also imply that PTEN may play a role in organizing the relationship of different cell types within an organ during development.
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PMID:Germline mutations of the PTEN gene in Cowden disease, an inherited breast and thyroid cancer syndrome. 914 Mar 96

We have synthesized and studied the ability of a series of seven novel 1 alpha,25(OH)2 vitamin D3 analogues to inhibit clonal growth of prostate cancer cells (LNCaP, PC-3 and DU-145). Addition of double and triple bonds to the C/D ring (C-16) and side chain (C-22 and C-23) as well as lengthening of the side chain were important for enhanced activity against LNCaP and PC-3. Reorientation of the side chain in the 20-epi configuration resulted in analogues that were extremely potent only against LNCaP (ED50 approximately 5 x 10(-11) M). Compounds with six fluorines on the end of the side chain were very active against both PC-3 and LNCaP (ED50 approximately 2 x 10(-8) M). DU-145 cells were relatively resistant to compounds with all of these modifications, but removal of C-19 (e.g. 1,25(OH)2-16-ene-23-yne-26,27-F6-19-nor-D3) resulted in an analogue that was inhibitory against all three prostate cell lines. Further analysis showed that pulse exposure (3 days, 10(-7) M) to this analogue was enough to inhibit clonal growth of PC-3 cells by 50%. The same exposure also induced cell cycle arrest of all three cell lines, accompanied by upregulated protein expression of the cyclin-dependent kinase inhibitor (CDKI) known as p21waf1 in all three cell lines, and the CDKI known as p27kip1 in LNCaP cells. Associated with upregulation of these CDKIs, partial differentiation occurred as measured by increased expression of both prostate-specific antigen by LNCaP cells and E-cadherin, a cell adhesion protein that may act as a putative tumour suppressor (LNCaP and PC-3 cells). In summary, this is the first report of a potent series of 19-nor-vitamin D3 analogues with the ability to inhibit proliferation of LNCaP, PC-3 and DU-145 prostate cancer cell lines. These compounds may mediate their potent anti-proliferative activities through a cell cycle arrest pathway.
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PMID:Inhibition of proliferation of prostate cancer cells by a 19-nor-hexafluoride vitamin D3 analogue involves the induction of p21waf1, p27kip1 and E-cadherin. 927 57

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


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