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)

Liver cancer is one of the major human tumors in the world. Basic and epidemiological studies have proposed that the major risk factors for liver cancer include alcohol and diet as well as infection with hepatitis B and C viruses. However, the mechanistic clues for the development of this type of cancer is largely unknown. Poly(ADP-ribose) polymerase (PARP-1) and a component of nonhomologous end-joining (NHEJ) machinery, Ku80, are two major DNA end-binding molecules that play a multifunctional role in DNA damage signaling and repair, recombination as well as the maintenance of genomic stability. Here we show that the interaction of PARP-1 and Ku80 is essential for development because PARP-1/Ku80 double null mice died at embryonic day (E) 9.5. Interestingly, haplo-insufficiency of Ku80 in PARP-1-/- mice promotes the development of hepatocellular adenoma and hepatocellular carcinoma (HCC). These tumors exhibited a multistage tumor progression associated with the loss of E-cadherin expression and the mutation of beta-catenin. Cytogenetic analysis revealed that Ku80 heterozygosity elevated chromosomal instability in PARP-1-/- cells and that these liver tumors harbored a high degree of chromosomal aberrations including fragmentations, end-to-end fusions, and recurrent nonreciprocal translocations (NRT). These features are reminiscent of human HCC. Taken together, these data implicate a synergistic function of Ku80 and PARP-1 in minimized chromosome aberrations and cancer development and suggest that defects in DNA end-processing molecules may be etiological factors in human HCC formation.
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PMID:Synergistic role of Ku80 and poly(ADP-ribose) polymerase in suppressing chromosomal aberrations and liver cancer formation. 1246 Sep 17

Gelsolin is a widely distributed actin binding protein involved in controlling cell morphology, motility, signaling and apoptosis. The role of gelsolin in tumor progression, however, remains poorly understood. Here we show that expression of green fluorescent protein (GFP)-tagged gelsolin in MDCK-AZ, MDCKtsSrc or HEK293T cells promotes invasion into collagen type I. In organ culture assays, MDCK cells expressing gelsolin-GFP invaded pre-cultured chick heart fragments. Gelsolin expression inhibited E-cadherin-mediated cell aggregation but did not disrupt the E-cadherin-catenin complex. Co-expression of dominant-negative Rac1N17, but not RhoAN19 or Cdc42N17, counteracted gelsolin-induced invasion, suggesting a requirement for Rac1 activity. Increased ARF6, PLD or PIP5K 1alpha activity canceled out gelsolin-induced invasion. Furthermore, we found that invasion induced by gelsolin is dependent on Ras activity, acting through the PI3K-Rac pathway via the Ras guanine nucleotide exchange factor Sos-1. These findings establish a connection between gelsolin and the Ras oncogenic signaling pathway.
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PMID:Gelsolin-induced epithelial cell invasion is dependent on Ras-Rac signaling. 1248 99

Tumor progression in epithelial tissues is characterized by a series of genetic and epigenetic changes that lead ultimately to metastasis. Alterations in E-cadherin and its cytoplasmic regulators, the catenins, have been implicated as central to this process. Here, we focus on p120-catenin and its rising incidence in the pathology literature as a molecule altered in human tumors. The data show that p120 is frequently altered and/or lost in tumors of the colon, bladder, stomach, breast, prostate, lung, and pancreas. Moreover, in some cases p120 loss appears to be an early event in tumor progression, possibly preceding loss of E-cadherin. Potential roles of p120 as a tumor suppressor or metastasis promoter are discussed.
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PMID:Altered expression of the catenin p120 in human cancer: implications for tumor progression. 1249 99

CD44 is a principal cell-surface receptor for hyaluronan (HA). Up-regulation of CD44 is often associated with morphogenesis and tumor invasion. On the contrary, reduction of cell-cell adhesion due to down-regulation of E-cadherin is associated with the invasive and metastatic phenotype of carcinomas. In our current study, we investigated the functional relationship between CD44 and E-cadherin. We established an inverse correlation between CD44 and E-cadherin indicating that the cells expressing higher levels of E-cadherin display weaker binding affinity between CD44 and HA. By using TA3 murine mammary carcinoma (TA3) cells, which display CD44-dependent HA binding, branching morphogenesis, and invasion, we demonstrated an inverse functional relationship between CD44 and E-cadherin by transfecting exogenous E-cadherin into the cells. Our results showed that increased expression of E-cadherin in TA3 cells, but not ICAM-1, weakens the binding between CD44 and HA and blocks spreading of the cells on HA substratum and CD44-mediated branching morphogenesis and tumor cell invasion. The results reported here demonstrated for the first time that E-cadherin negatively regulated CD44-HA interaction and CD44 function and suggested that balanced function of CD44 and E-cadherin may be essential for normal epithelial cell functions, and imbalanced up-regulation of CD44 function and/or down-regulation of E-cadherin function likely contributes to tumor progression.
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PMID:E-cadherin negatively regulates CD44-hyaluronan interaction and CD44-mediated tumor invasion and branching morphogenesis. 1251 69

To understand the role of gene promoter methylation in neoplastic evolution and progression, the methylation changes associated with 15 candidate tumor suppressor genes were studied throughout stages of tumor progression involving intraductal papillary mucinous neoplasms (IPMN) of the pancreas. Genomic DNA from 28 pancreatic IPMN tissue samples, categorized histologically as non-invasive intraductal IPMN (n = 3), IPMN with carcinoma in situ (n = 7), IPMN with microinvasion <1 mm (n = 4), and infiltrative IPMN with associated adenocarcinoma (n = 14), was modified by bisulfite treatment and analyzed with methylation-specific PCR (MSP). Promoter methylation of at least one tumor suppressor gene was present in 26/28 (92%) of the IPMNs. The cell cycle control genes, p16 and p73, were methylated frequently (>50%) in both non-invasive and invasive tumors. APC methylation was discovered in <10% of the non-invasive IPMNs versus 45% of the IPMNs associated with infiltrative adenocarcinoma, P = 0.040. Mismatch repair genes, hMLH1 and MGMT, were frequently methylated in the invasive IPMNs compared with the non-invasive tumors (38 versus 10% and 45 versus 20%, respectively) as was E-cadherin (38 versus 10%), P = 0.11. Multiple gene methylation at greater than three loci was present in 55% of the invasive tumors compared with 20% of the non-invasive tumors, P = 0.075. Lymph node status did not predict multi-gene methylation among tumors associated with invasive cancer. Compared with non-invasive IPMNs of the pancreas, IPMNs associated with adenocarcinoma demonstrate higher rates of aberrant tumor suppressor gene methylation. The sequential acquisition of hypermethylation at multiple gene promoter sites may explain tumor progression in IPMNs and other malignancies. Detection of methylation within selected genes may afford an accurate diagnostic molecular marker and predictor of neoplastic behavior.
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PMID:Molecular progression of promoter methylation in intraductal papillary mucinous neoplasms (IPMN) of the pancreas. 1258 67

Proprotein convertases (PCs) are known to activate many important molecules and their overexpression plays a significant role in tumor progression. Only little is known about the involvement of PCs in the processing of cadherin adhesion molecules, which are potent tumor suppressors. Here we show in a baculovirus overexpression system that the desmosomal cadherins Dsg1 and Dsg3 are substrates for the PC furin. Accordingly, inhibition of PCs in differentiating mouse keratinocytes by alpha 1-anti-trypsin Portland (alpha 1-PDX) negatively interfered with pro-epithelial (proE)-cadherin processing, but unexpectedly also resulted in a dramatic reduction of E-cadherin, Dsg1 and Dsg3 protein and Dsg1 mRNA. Because loss of intercellular adhesion is a rate-limiting step in the transition from benign to malignant tumors, these results have significant implications for the use of PC inhibitors as possible therapeutic tools.
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PMID:Novel insights into cadherin processing by subtilisin-like convertases. 1258 64

Loss of E-cadherin expression is a major characteristic of highly invasive and metastatic cancers. Epithelial-mesenchymal transition (EMT) has been advocated to be a causative mechanism for the suppression of E-cadherin and tumor progression. Snail is a zinc finger transcription factor that triggers the EMT and is one of the recently identified E-cadherin repressors. The reverse correlation of Snail and E-cadherin expressions has been reported in many types of human cancers including squamous cell carcinoma (SCC). In this study, we showed that three E-cadherin negative SCC cell lines had a fibroblastic morphology, strong expressions of vimentin, a mesenchymal marker gene, and Snail. Compared to other E-cadherin positive SCC cells, these cells showed higher invasive ability and expression of MMP-2, a matrix degrading enzyme which has been demonstrated to be highly expressed in invasive cancer cells. Over-expression of Snail in A431 cells resulted in the loss of E-cadherin expression, the change of their morphology to fibroblastic, and the up-regulation of vimentin gene expression, indicating that an EMT was induced by Snail. Furthermore, these cells became more invasive and showed higher levels of MMP-2 activity and its gene expression. Luciferase analysis demonstrated that the MMP-2 promoter activity was induced by Snail transfection and the promoter region from -262 to -411 relative to the transcriptional start site was necessary for this induction. These results indicate that Snail is a new inducer of MMP-2 expression and suggest that the EMT contributes to the increased invasion not only through the inhibition of cell-cell adhesion but also the up-regulation of MMP-2 expression in SCC cells.
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PMID:Increased invasion and matrix metalloproteinase-2 expression by Snail-induced mesenchymal transition in squamous cell carcinomas. 1263 84

The Snail transcription factor has been described recently as a strong repressor of E-cadherin in epithelial cell lines, where its stable expression leads to the loss of E-cadherin expression and induces epithelial-mesenchymal transitions and an invasive phenotype. The mechanisms regulating Snail expression in development and tumor progression are not yet known. We show here that transforming growth factor beta-1 (TGFbeta1) induces Snail expression in Madin-Darby canine kidney cells and triggers epithelial-mesenchymal transitions by a mechanism dependent on the MAPK signaling pathway. Furthermore, TGFbeta1 induces the activity of Snail promoter, whereas fibroblast growth factor-2 has a milder effect but cooperates with TGFbeta1 in the induction of Snail promoter. Interestingly, TGFbeta1-mediated induction of Snail promoter is blocked by a dominant negative form of H-Ras (N17Ras), whereas oncogenic H-Ras (V12Ras) induces Snail promoter activity and synergistically cooperates with TGFbeta1. The effects of TGFbeta1 on Snail promoter are dependent of MEK1/2 activity but are apparently independent of Smad4 activity. In addition, H-Ras-mediated induction of Snail promoter, alone or in the presence of TGFbeta1, depends on both MAPK and phosphatidylinositol 3-kinase activities. These data support that MAPK and phosphatidylinositol 3-kinase signaling pathways are implicated in TGFbeta1-mediated induction of Snail promoter, probably through Ras activation and its downstream effectors.
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PMID:Transforming growth factor beta-1 induces snail transcription factor in epithelial cell lines: mechanisms for epithelial mesenchymal transitions. 1266 27

Tumor progression involves the transition from normal to malignant cells, through a series of cumulative alterations. During this process, invasive and migratory properties are acquired, enabling cells to metastasize (reach and grow in tissues far from their origin). Numerous cellular changes take place during epithelial malignancy, and disruption of E-cadherin based cell-cell adhesion is a major event. The small Rho GTPases (Rho, Rac and Cdc42) have been implicated in multiple steps during cellular transformation, including alterations on the adhesion status of the tumor cells. This review focuses on recent in vivo evidence that implicates RhoGTPases in epithelial tumor progression. In addition, we discuss different hypotheses to explain disruption of cadherin-mediated cell-cell adhesion, directly or indirectly, through activation of Rho GTPases. Understanding the molecular mechanism of how cadherin adhesion and RhoGTPases interplay in normal cells and how this balance is altered during cellular transformation will provide clues as to how to interfere with tumor progression.
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PMID:Tumor progression: Small GTPases and loss of cell-cell adhesion. 1271 16

In this study we used liver neoplasms induced by several chemical carcinogens to investigate potential nuclear targets associated with beta-catenin/Wnt signaling and potential membrane-associated beta-catenin binding partners. Strong expression of cyclin D1, in a pattern similar to that observed previously for beta-catenin, was observed by Western analysis for all five hepatoblastomas examined regardless of treatment. Increased expression of cyclin D1 was also detected in 12 of 35 (34%) hepatocellular neoplasms. Ten of 15 tumors (67%) that had mutations in the Catnb gene had upregulation of cyclin D1, while only 2 of 20 tumors (10%) without Catnb mutations had increased cyclin D1 expression. Immunohistochemical analysis confirmed strong expression of cyclin D1 in most nuclei of hepatoblastomas and scattered nuclear staining in hepatocellular tumors that had Catnb mutations. Increased c-Jun expression was observed in 19 of 30 (63%) hepatocellular tumors and all hepatoblastomas, although upregulation was not completely correlated with Catnb mutation. C-Myc expression was not increased in the tumors. Reduced expression of E-cadherin, which interacts with beta-catenin at the membrane, was observed in some tumors, but this did not correlate with Catnb mutation. Expression of the epidermal growth factor receptor, which may have a role in beta-catenin tyrosine phosphorylation, was lower in some tumors than in normal tissue depending on chemical treatment. The results provide evidence that increased expression of cyclin D1 and c-Jun may provide an advantage during tumor progression and in the transition from hepatocellular neoplasms to hepatoblastomas. Moreover, it is likely increased cyclin D1 expression results at least in part from Catnb mutation, beta-catenin accumulation, and increased Wnt signaling.
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PMID:Expression of potential beta-catenin targets, cyclin D1, c-Jun, c-Myc, E-cadherin, and EGFR in chemically induced hepatocellular neoplasms from B6C3F1 mice. 1287 43


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