Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UMLS:C0178874 (tumor progression)
40,807 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The use of in vitro cell transformation, as a complement to the direct study of tumors and established tumor cell lines, has enabled the analysis of the contribution of diverse genes to the tumor phenotype. The most recent results have underlined the importance of fundamental mechanisms regulating cell proliferation. The role in the long term survival of mammalian cells in culture and in tumor progression of the telomerase enzyme, which permits the maintenance of chromosome ends integrity, has now been demonstrated. Cell cycle progression and its regulation are ensured by a positive control exerted by cyclin-kinase complexes and by a negative one exerted by kinase inhibitors. Cyclin and kinase genes are frequently altered in transformed and tumor cells, as well as the genes coding for membrane proteins responsible for cell-cell and cell-matrix contacts.
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PMID:[Cell transformation]. 852 94

p21WAF1/Cip1 is an inhibitor of cdk/cyclin complexes, and thus regulates the cell cycle. p21 is also related to cell differentiation and is regulated by wild-type p53, although p53-independent regulatory pathways have been proposed. In order to analyse p21 expression as well as its relationship with p53 in human breast cancer, an immunohistochemical analysis was undertaken of 77 breast carcinomas, 16 of them with an in situ component; 30 adjacent normal tissue samples; and five non-neoplastic specimens. Forty-four infiltrating carcinomas (57 per cent) were p21-positive. Expression of p21 was also observed in pre-invasive lesions, whereas normal ducts were negative or focally and weakly positive. p21 expression was associated with high histological grade (II + III) (P = 0.017) and poor tubule formation (P = 0.002), and was significantly less frequent in lobular carcinomas (P = 0.0001). p21 positivity also correlated with increased proliferation, but this seemed to be dependent on the histological grade. Twenty carcinomas (26 per cent) showed p53 overexpression, but this was not associated with p21 negativity, suggesting the existence of p53-independent mechanisms for p21 regulation in vivo. Cyclin D1CCND1 expression was analysed in the same series and an association between p21 and cyclin D1 expression was found, since 23 of 26 cyclin D1-positive carcinomas were p21-positive (P < 0.001 ...). In conclusion, p21 is frequently overexpressed in breast carcinomas and this occurs in the early stages of neoplastic progression. This overexpression seems to be independent of p53 status and might be involved in cyclin D1 modulation.
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PMID:p21WAF1/Cip1 is associated with cyclin D1CCND1 expression and tubular differentiation but is independent of p53 overexpression in human breast carcinoma. 961 78

Cyclin-D1 (CD1) expression was analyzed in human mammary carcinomas by immunohistochemical (IHC) and flow-cytometry (FCM) methods: 52.5% and 50% of cases were strong expressors of CD1 by IHC and FCM analysis respectively. The percentage of CD1-positive cells was especially high in node-negative (N-) estrogen-receptor-positive (ER+) tumors, probably as a consequence of CD1 induction by estrogens in steroid-responsive tissues. However, CD1 expression was not related to ER positivity in node-positive tumors (N+). An interesting relationship between CD1 expression and H3-thymidine labelling index (H3Td-LI) was also found: CD1 and H3Td-LI were unrelated in N- tumors, while high CD1 expression was observed in N+ tumors with high DNA synthesis, as assessed by H3Td-LI. The combined measurement of DNA and CD1 showed that 27 specimens were aneuploid, 19 of them (19/27; 70%) strongly expressing CD1. Further studies are needed to clarify the role of CD1 in DNA abnormality of breast tumors. However, we cannot exclude that the CD1 may be differently de-regulated in the last phase of tumor progression, and that CD1 over-expression may contribute to the aneuploidy of mammary carcinomas.
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PMID:Cyclin-D1 expression in node-positive (N+) and node-negative (N-) infiltrating human mammary carcinomas. 1009 45

SV40 large T antigen-induced primitive neuroectodermal tumors of the rat provide a model system to study induction and progression of primitive neuroectodermal tumors at the molecular level. A cell line derived from such a tumor reproducibly gave rise to malignant derivatives that ceased large T-antigen expression but harbored a mutant p53 allele with a common mutation at Cys(174) to Tyr (C174Y). To determine whether this p53 mutation contributes to tumor progression, we analyzed mutant C174Y functionally. Co-transfection experiments in Saos-2 cells with mutant or wild-type p53 and reporter genes linked to various p53-responsive promoters revealed that mutant C174Y failed to transcriptionally transactivate the Mdm2, Waf1, Cyclin G and Bax promoters. Loss of transcriptional activation correlated with loss of DNA-binding activity. Moreover, mutant C174Y exhibited a dominant negative effect on co-expressed wild-type p53. The ability of mutant p53 to repress the viral RSV, LTR or SV40 early promoters or the cellular fos promoter was likewise impaired. In contrast, it showed even induction of the fos promoter. Consistent with these observations, mutant C174Y was non-functional in the suppression of Saos-2 cell growth and even conferred a growth advantage to the cells. Surprisingly, mutant C174Y was also impaired in nuclear transport, as revealed by immunofluorescence analyses. Taken together, our results demonstrate that mutant C174Y possesses features that can positively contribute to cancer progression.
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PMID:Tumor-derived p53 mutant C174Y is a gain-of-function mutant which activates the fos promoter and enhances colony formation. 1100 63

Traditional prognostic indicators for astrocytic tumors include tumor size, type, and histologic grade. Data suggest that tumor growth fraction assessed by MIB-1 is an important predicator of survival. Cyclin A, like MIB-1, is a recently described specific marker of proliferation, detectable primarily in S phase of the cell cycle as it undergoes progression to G2 phase. Thirty-seven cases of astrocytic tumors--14 cases of World Health Organization grade 1 and 2 (low grade tumors), 8 cases of grade 3 (anaplastic astrocytoma), and 15 cases of grade 4 (glioblastoma multiforme)--were simultaneously evaluated using routine paraffin immunohistochemical methods with commercial antibodies against MIB-1 and cyclin A. The results were quantitated using a Cell Analysis System (CAS) 200 image analyzer. The mean percentage positive nuclear area for MIB-1 was 3.32% in grade 1 and 2, 19.27% in grade 3, and 24.00% in grade 4 astrocytic tumors. Cyclin A showed a similar pattern of positivity in the same cases: 2.84% in grade 1 and 2, 16.27% in grade 3, and 24.88% in grade 4 astrocytic tumors. The data suggest that both proliferation markers correlated significantly with histologic grade. Cyclin A appears to be as good an indicator of brain tumor proliferation as MIB-1. Because cyclin A is detectable primarily in the S phase of the cell cycle, the fraction of cells positive for cyclin A should allow for a more accurate indicator of tumor progression.
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PMID:Comparison of cyclin A and MIB-1 expression in astrocytic tumors using image-based cell analysis system. 1127 8

Centrosome duplication plays an important role in genomic stability through bipolar spindle formation and equal chromosome segregation during mitosis. Defects in centrosome duplication and centrosome amplification correlate with aggressive tumors and aneuploidy. Cyclin-dependent cell cycle regulators play a key role in signaling centrosome duplication and the tumor suppressor genes p53, BRCA1 and BRCA2 are suspected to function at mitotic checkpoints that monitor centrosome duplication. The relationship between loss of hormone dependence in breast cancer, and signaling of centrosome duplication in tumor progression is not known. We have developed a MCF-7 cell line expressing GFP-centrin that allows direct visualization of centriole duplication during the cell cycle in living cells. GFP-centrin is expressed and selectively incorporated into the structure of both centrioles making them clearly visible in living cells. Our studies demonstrate three important aspects of recombinant GFP-centrin incorporation into centrioles. 1) GFP-centrin transfected cells grow normally in culture and show no adverse effect associated with GFP-centrin expression; 2) newly duplicated centrioles incorporate centrin during their genesis; and 3) GFP-centrin incorporation into centrioles does not grossly affect cell cycle progression, or centrosome function.
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PMID:GFP-centrin as a marker for centriole dynamics in the human breast cancer cell line MCF-7. 1172 45

Mammalian cells express two homologs of the SWI2 subunit of the SWI/SNF chromatin-remodeling complex called BRG1 and BRM. Whether the SWI/SNF complexes formed by these two subunits perform identical or different functions remains an important question. In this report, we show concomitant down-regulation of BRG1 and BRM in six human tumor cell lines. This down-regulation occurs at the level of mRNA abundance. We tested whether BRM could affect aberrant cellular functions attributed to BRG1 in tumor cell lines. By transient transfection, we found that BRM can restore RB-mediated cell cycle arrest, induce expression of CD44 protein and suppress Cyclin A expression. Therefore, BRM may be consistently down-regulated with BRG1 during neoplastic progression because they share some redundant functions. However, assorted tissues from BRM null/BRG1-positive mice lack CD44 expression, suggesting that BRM-containing SWI/SNF complexes regulate expression of this gene under physiological conditions. Our studies further define the mechanism by which chromatin-remodeling complexes participate in RB-mediated cell cycle arrest and provide additional novel evidence that the functions of SWI/SNF complexes containing BRG1 or BRM are not completely interchangeable.
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PMID:Concomitant down-regulation of BRM and BRG1 in human tumor cell lines: differential effects on RB-mediated growth arrest vs CD44 expression. 1185 Aug 39

Cyclin A is required for DNA synthesis during the S phase and progression through the G2/M transition. Increased expression of cyclin A protein has been correlated with poor prognosis in a variety of human tumors. To investigate the possible influence(s) of cyclin A protein on the progression and prognosis of oral squamous cell carcinomas (SCCs) in Taiwan. We examined the expression of cyclin A in oral SCC, epithelial dysplasia (ED) and normal oral mucosa (NOM) by immunohistochemistry using antibodies to cyclin A. Results and Conclusions. The mean labeling indices (LI) in NOM, ED and SCCs were 7.0+/-3.1%, 12.1+/-3.9% and 21.3+/-12.3%, respectively. The cyclin A LI for oral SCCs was significantly higher than that for NOM (P=0.002) or ED (P<0.001). In addition, a high LI for cyclin A was found to correlate with advanced stage (P=0.0048), larger tumor size (P=0.0017), lymph node involvement (P=0.0006) and cancer recurrence (P<0.0001). The Kaplan-Meier analysis showed patients with tumors containing more than 15% cyclin A-positive cells had significantly shorter overall survival than those with tumors containing less than 15% cyclin A-positive cells (P<0.00001). These results indicate that overexpression of cyclin A protein is associated with tumor progression and patient prognosis for oral SCC.
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PMID:Expression of cyclin A is related to progression of oral squamous cell carcinoma in Taiwan. 1274 72

The anatomic distribution and rate of progression vary significantly between acquired immunodeficiency syndrome (AIDS)-related Kaposi sarcoma (KS) and classic KS. The reasons are unclear, but cyclin D1 overexpression is associated with tumor progression in other malignancies. Cyclin D has an important regulatory role in the progression of cell cycle at the G1-S phase due to its effect in phosphorylating the retinoblastoma gene product. Forty-one paraffin-embedded surgical specimens (31 AIDS-related, 10 classic) were examined using streptavidin-biotin-peroxidase immunohistochemistry with monoclonal antibody to cyclin D1. A scoring system based on the intensity and extent of staining was used. The correlations among cyclin D1 expression and clinicopathologic parameters were statistically analyzed. Cyclin D1 overexpression was found in 29% (12/41) of all KS cases. There was a strong correlation between cyclin D1 overexpression and pathologic stage (0% in patch stage, 13% in plaque stage, 50% in nodular stage; P = 0.0017). Classic KS lesions had a higher incidence of cyclin D1 overexpression than AIDS-related lesions (70% vs 16%, P = 0.001). Cyclin D1 overexpression was detected in 78% of the classic nodular lesions and 31% of the AIDS-related nodular lesions (P = 0.03). On multivariate analysis, negative human immunodeficiency virus status (P = 0.001) and nodular lesions (P = 0.007) were strong predictors of cyclin D1 overexpression. Age, gender, recurrence of the tumor, multiplicity, and site of the lesions hold no statistically significant association with cyclin D1 expression on multivariate analysis. In summary, cyclin D1 overexpression was more prevalent in classic lesions and more advanced nodular stage. These findings raise the possibility of a different pathogenetic mechanism in the progression of AIDS-related KS and classic KS.
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PMID:Cyclin D1 overexpression in AIDS-related and classic Kaposi sarcoma. 1516 15

The proinflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) promotes tumor progression through activation of matrix metalloproteinase (MMP) activity. MMP-9 is a gelatinase secreted by both cancer cells and surrounding stromal cells, and it contributes to TNF-alpha-stimulated tumor invasion and metastasis. Cyclin-dependent kinase 9 (CDK9), the catalytic component of positive transcription elongation factor-b, phosphorylates serine 2 residues in the C-terminal domain of RNA polymerase II for productive transcription elongation and is up-regulated upon exposure to various stresses. This study investigated roles of CDK9 in TNF-alpha-stimulated MMP-9 expression in human lung adenocarcinoma cells. CDK9 activity was inhibited using three different strategies, including the CDK9 pharmacological inhibitor 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB), a dominant-negative CDK9, and a CDK9-specific small interfering RNA. All three approaches reduced TNF-alpha-mediated accumulation of MMP-9 in the conditioned media as demonstrated by gelatin zymography. In contrast, transforming growth factor-beta1-induced accumulation of MMP-2 was unaffected by DRB. Expression of the MMP-9 gene was examined using reverse transcription real time PCR and using a transient transfection assay to evaluate MMP-9 promoter activity. DRB reduced the TNF-alpha-induced increase in MMP-9 mRNA levels but did not effect transforming growth factor-beta1-induced MMP-2 mRNA expression. Consistently DRB and dominant-negative CDK9 completely abrogated TNF-alpha-stimulated human MMP-9 promoter activity. TNF-alpha did not regulate expression or localization of CDK9 or its regulatory partner Cyclin T. However, TNF-alpha stimulated CDK9 binding to Cyclin T and MMP-9 gene occupancy by both CDK9 and the serine 2-phosphorylated form of RNA polymerase II. Our findings indicate that CDK9 mediates TNF-alpha-induced MMP-9 transcription. Disruption of TNF-alpha signaling using CDK9 inhibitors could serve as a potential therapeutic strategy against tumor invasion and metastasis.
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PMID:Cyclin-dependent kinase 9 is required for tumor necrosis factor-alpha-stimulated matrix metalloproteinase-9 expression in human lung adenocarcinoma cells. 1552 90


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