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)

Inhibin was first identified as a gonad-derived regulator of pituitary FSH; however, it has subsequently been shown to be a tumour suppressor in the gonad and adrenal glands. Whereas non-malignant regions of human primary prostate carcinomas express inhibin alpha-subunit (INHA), malignant tissues lack INHA transcript and protein, which is consistent with epigenetic regulation of the inhibin alpha-subunit gene (INHA) promoter. This study investigated whether methylation of the INHA promoter was responsible for inactivation of INHA transcription and translation in the prostate cancer cell lines, LNCaP, DU145 and PC3. Methylation of the promoter was revealed by bisulphite genomic sequencing and use of inhibitors of methylation and histone deacetylation resulted in reactivation of the INHA transcription and translation. Significant (P<0.05) downregulation of a luciferase reporter gene downstream from a methylated INHA promoter compared with unmethylated INHA promoter occurred in vitro. The data demonstrate that promoter methylation is associated with downregulation of the INHA gene in prostate cancer cell lines, which is consistent with its tumour suppressive role. Therefore INHA has a significant role in prostate tumorigenesis.
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PMID:Epigenetic regulation of inhibin alpha-subunit gene in prostate cancer cell lines. 1476 92

Development of any cancer reflects a progressive accumulation of alterations in various genes. Oncogenes, tumour suppressor genes, DNA repair genes and metastasis suppressor genes have been investigated in prostate cancer. Here, we review current understanding of the molecular biology of prostate cancer. Detailed understanding of the molecular basis of prostate cancer will provide insights into the aetiology and prognosis of the disease, and suggest avenues for therapeutic intervention in the future.
Prostate Cancer Prostatic Dis 2004
PMID:Molecular biology of prostate cancer. 1499 33

E2F-1 is a pivotal transcription factor that integrates signals from a variety of G1/S phase regulators and modulates diverse cellular functions, such as DNA synthesis, repair, mitosis, and apoptosis. Its role in cellular proliferation and apoptosis, as depicted from experimental models and limited reports in human malignancies, remains a matter of debate. Recently, in non-small cell lung cancer, it was observed that E2F-1 overexpression was associated with tumour growth, implying an 'oncogenic' effect. To clarify further the role of E2F-1 in carcinogenesis, the investigation was expanded in four of the most common human malignancies by examining its expression status and putative impact on tumour kinetics. These issues were addressed by immunohistochemical and molecular means in 52 breast carcinomas, 42 prostate adenocarcinomas, 58 colon adenocarcinomas, and 77 superficial bladder transitional cell carcinomas (TCCs). The following results were found: (i). in breast carcinomas, E2F-1 expression correlated with proliferation (p < 0.001) and growth index (p = 0.001); (ii). in prostate adenocarcinomas, absence of E2F-1 was noted, in contrast to its expression in normal and hyperplastic glands; (iii). in colon adenocarcinomas, E2F-1 expression was inversely related to growth index (p = 0.001), being expressed in lesions with increased apoptosis (p = 0.001) and low proliferation (p < 0.001); and (iv) in superficial TCCs, E2F-1 expression correlated with proliferation (p = 0.002). Taken together, these results suggest that E2F-1 has a growth-promoting effect in breast carcinomas and superficial TCC, whereas the opposite seems to be the case for colon and prostate cancer. To interpret the above findings, the status of the pRb and p53 tumour suppressor pathways, which are known to affect E2F-1 activity, was further investigated. The results suggest that the actions of E2F-1 are mainly dependent on the functionality of these pathways. Nevertheless, the data also imply that p53-independent pathways may play a nodal role in the function of E2F-1 in colon cancer.
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PMID:Distinct expression patterns of the transcription factor E2F-1 in relation to tumour growth parameters in common human carcinomas. 1522 33

The inhibin field has been perplexed by the information that inhibin alpha is a tumour suppressor in mice yet is elevated in women with ovarian cancer. Furthermore, we have consistently observed a down-regulation or loss of inhibin alpha in prostate cancer patient samples and cell lines. However, our latest data have prompted us to re-evaluate the role of inhibin alpha in prostate and other cancers. Using the analogy of TGF-beta as a springboard for our hypothesis, we offer a unifying model whereby the previously conflicting observations in mice, men and women can be explained. We propose that initially inhibin alpha is tumour-suppressive and is expressed in benign and early-stage primary cancers. Tumour-suppressive inhibin alpha is then silenced as the tumour progresses but is reactivated as a pro-metastatic factor in advanced, aggressive cancers.
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PMID:Cancer progression: is inhibin alpha from Venus or Mars? 1545 Feb 47

Abnormal signalling events mediated by receptor tyrosine kinases (RTKs) contribute to human carcinogenesis. Sprouty2 (Spry2) is a key antagonistic regulator of RTK signalling and suppression of its expression or function may facilitate proliferation and angiogenesis. Using prostate cancer (CaP) as a model, we investigated the significance of Spry2 in human malignancy. We observed downregulated Spry2 expression in invasive CaP cell lines and high-grade clinical CaP (compared to benign prostatic hyperplasia (BPH) and well-differentiated tumours, P=0.041). A large CpG island is associated with hSPRY2, and extensive hypermethylation of this CpG island was observed in 76-82% of high-grade CaP, while control BPH tissues were predominantly unmethylated (P=0.0005). Furthermore, suppressed Spry2 expression correlated with methylation of the CpG region in clinical samples (P=0.004) and treatment with 5-aza-2'-deoxycytidine reactivated Spry2 expression in LNCaP and PC-3M cells. hSPRY2 maps to the long arm of chromosome 13 (13q31.1), where loss of heterozygosity (LOH) has been reported. We found no evidence of mutation; however, we demonstrated 27-40% LOH using flanking markers to hSPRY2. Hence, while biallelic epigenetic inactivation of hSPRY2 represents the main genetic event in prostate carcinogenesis, the observed 27-40% LOH presents evidence of hemizygous deletion with the remaining allele hypermethylated. We therefore propose hSPRY2 as a potential tumour suppressor locus in CaP.
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PMID:Epigenetic inactivation of the human sprouty2 (hSPRY2) homologue in prostate cancer. 1573 53

The prostate is a highly androgen-dependent tissue that in humans exhibits marked susceptibility to carcinogenesis. The malignant epithelium generated from this tissue ultimately loses dependence on androgens despite retention or amplification of the androgen receptor. Accumulating evidence support that transforming growth factor-beta (TGF-beta) plays key roles in the control of androgen dependence and acquisition of resistance to such hormonal control. Although TGF-beta functions as a key tumour suppressor of the prostate, it can also promote malignant progression and metastasis of the advanced disease, through undefined mechanisms. In addition to giving an overview of the TGF-beta field as related to its function in prostate cancer, this Review focuses on novel findings that support the tumour suppressor function of TGF-beta is lost or altered by changes in the activity of the androgen receptor, insulin-like growth factor-I, Akt, and mTOR during malignant progression. Understanding the mechanisms of cross-talk between TGF-beta and such growth modulators has important implications for the rational therapeutics of prostate cancer.
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PMID:Functions and regulation of transforming growth factor-beta (TGF-beta) in the prostate. 1580 54

Hungary is among the leading countries in Europe regarding the mortality and incidence of different types of tumours. Therefore, developing effective therapies is especially important in this country. Investigation of tumour formation and progression on the molecular level is required to develop possible therapeutical targets. Such targets can be proteins with tumour suppressor function, which inhibit intracellular signalling processes that under pathophysiological conditions can lead to uncontrolled cell proliferation and tumour formation. Protein e3B1/Abi-1, which belongs to the family of Abl-interactors, was isolated recently as a possible tumour suppressor. As a partner of Abl kinase, its role has been investigated in the development and progression of some types of leukemias, however, more and more experimental data suggest that it is a general suppressor protein. According to the latest results, e3B1/Abi-1 via the Ras small G-protein has an essential role in the regulation of cell proliferation, and via Rac activation it can affect actin remodelling, cell adhesion and migration. Cell proliferation is important in tumour development, while cell adhesion and migration has a role in metastasis formation. The latest results showed deletion of the gene encoding protein e3B1/Abi-1 in prostate cancer, loss of its expression during the progression of some types of leukemias, and there are data on the effect of imatinib mesylate (Gleevec or outside USA Glivec, Novartis), one of the newest drugs in leukemia treatment, on the phosphorylation of e3B1/Abi-1 as well. This report summarizes the data published on protein e3B1/Abi-1, with special interest in practical implications.
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PMID:[The role of EGF receptor-dependent e3B1/Abi1 protein as a tumor suppressor protein in malignant tumors]. 1602 98

The transforming growth factor-beta (TGFbeta) superfamily and its downstream effector genes are key regulators of epithelial homeostasis. Altered expression of these genes may be associated with malignant transformation of the prostate gland. The cDNA array analysis of differential expression of the TGFbeta superfamily and functionally related genes between patient-matched noncancerous prostate (NP) and prostate cancer (PC) bulk tissue specimens highlighted two genes, namely TGFbeta-stimulated clone-22 (TSC-22) and Id4. Verification of their mRNA expression by real-time PCR in patient-matched NP and PC bulk tissue, in laser-captured pure epithelial and cancer cells and in NP and PC cell lines confirmed TSC-22 underexpression, but not Id4 overexpression, in PC and in human PC cell lines. Immunohistochemical analysis showed that TSC-22 protein expression in NP is restricted to the basal cells and colocalizes with the basal cell marker cytokeratin 5. In contrast, all matched PC samples lack TSC-22 immunoreactivity. Likewise, PC cell lines do not show detectable TSC-22 protein expression as shown by immunoblotting. TSC-22 should be considered as a novel basal cell marker, potentially useful for studying lineage determination within the epithelial compartment of the prostate. Conversely, lack of TSC-22 seems to be a hallmark of malignant transformation of the prostate epithelium. Accordingly, TSC-22 immunohistochemistry may prove to be a diagnostic tool for discriminating benign lesions from malignant ones of the prostate. The suggested tumour suppressor function of TSC-22 warrants further investigation on its role in prostate carcinogenesis and on the TSC-22 pathway as a candidate therapeutic target in PC.
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PMID:Differential expression of TGFbeta-stimulated clone 22 in normal prostate and prostate cancer. 1610 24

Mutations of the 'phosphatase and tensin homologue deleted on chromosome 10' (PTEN/MMAC1) gene have been associated with a variety of human cancers, including prostate cancer, glioblastoma, and melanoma. The gene is thought to be one of the most frequently mutated tumour suppressor genes and inactivation of PTEN is associated with disease progression and angiogenesis. High vascularization and resistance to chemo- and radio-therapy are two well-established features of phaeochromocytomas (PCCs). Furthermore, benign and malignant PCCs are found in several PTEN knockout mouse models. This study therefore evaluated whether inactivation of PTEN may be involved in the tumourigenesis of PCC in man and whether PTEN abnormalities may help to define the malignant potential of these tumours. Tumour and germline DNA was analysed from 31 patients with apparently sporadic PCC, including 14 clinically benign and 17 malignant tumours, for loss of the PTEN gene locus, mutations in the PTEN gene, and for PTEN protein expression by immunohistochemistry. Loss of heterozygosity (LOH) analysis showed loss of PTEN in four malignant tumours (40%) and in one benign tumour (14%). However, no mutations of PTEN were observed. Immunohistochemistry showed no correlation with clinical behaviour and/or LOH status. The results indicate that inactivation of the PTEN/MMAC1 gene may play a minor role in the development of malignant phaeochromocytomas.
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PMID:PTEN gene loss, but not mutation, in benign and malignant phaeochromocytomas. 1653 14

ARLTS1--a member of ADP-ribosylation factor family, is a newly described candidate tumour suppressor gene. Recent studies show that a nonsense polymorphism, G446A (Trp149Stop), in ARLTS1 gene is significantly more frequent in familial cancer cases than in sporadic cancer cases. This study presents analysis of the germ-line G446A polymorphism in the ARLTS1 gene among 1686 consecutively collected patients with breast cancer, prostate cancer, malignant melanoma, thyroid papillary cancer or laryngeal cancer in Poland. The G446A allele was present in 1.81% (9/497) breast cancer patients, 1.46% (5/343) prostate cancer patients, 1.76% (7/397) melanoma patients, 1.65% (3/182) thyroid papillary carcinoma patients and 2.68% (8/299) of laryngeal cancer patients. The frequency of this polymorphism in the control group was 1.45% (8/552). Differences in the frequency of the G446A polymorphism between case and control groups were not statistically significant. In addition, there was no significant difference in the number of Cancer Familial Aggregations (CFA) among breast, prostate, thyroid or laryngeal cancer cases harbouring the G446A polymorphism, when compared to the G446A negative cases. Interestingly out of the CFA melanoma cases, 4/6 (66.6%) were found to harbour the change compared to only 20.2% (69/341) sporadic melanoma cases. This difference was statistically significant (p = 0.02, OR = 7.8). The results of this study suggest that the G446A in ARLTS1 gene is probably not associated with an increased risk of sporadic breast cancer, prostate cancer, melanoma, thyroid papillary cancer or laryngeal cancer. Moreover, the G446A polymorphism is not significantly more frequent in CFA cases except for families in which the proband had melanoma. To confirm this result more cases of melanoma should be analysed.
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PMID:Cancer Familial Aggregation (CFA) and G446A polymorphism in ARLTS1 gene. 1657 Jan 16


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