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Query: UMLS:C0596263 (carcinogenesis)
 64,820 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To elucidate the role of matrix metalloproteinases (MMP) in carcinogenesis, the expression of collagenases of types I (MMP-I) and IV (MMP-2 and MMP-9) as well as the behaviour of urokinase-like plasminogen activator (uPA) and of tissue MMP inhibitors (TIMP) in immortalized (IF) and transformed (TF) fibroblasts were investigated. The study was carried out using embryo rat fibroblasts, sequentially immortalized with the LT gene of human papilloma virus and transformed with the E7 gene of human papilloma virus (HPV-16). As control was used the primary fibroblast (PF) culture of Fisher rats. In IF, the collagenase activity was at the same level as it was in PF. The activity of uPA in IF was increased by 2-2.5-fold; the titrated amount of free endogenous inhibitors in IF and PF was at essentially the same level while being markedly higher than in TF. At the stage of fibroblast transformation with the E7 gene of HPV-16, there was seen an increase of Type IV collagenases and a decrease of Type I collagenase, both these indices being most pronounced in the cells with most developed tumorigenic properties. In TF there occurred a decrease of free endogenous MMP inhibitors relative to the enzyme activity and, at the same time, a decrease in uAF activity, indicating the changes occurring in the enzyme/inhibitor/activator ratio and hence the enhancement of the destructive potential of the cells (in this case, at the cost of Type IV collagenase activity).
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PMID:[Type I and IV collagenases and their endogenous regulators in immortalized and transformed fibroblasts]. 1138

Tumour progression to the metastatic phenotype is mainly dependent on tumour cell invasiveness. Cell migration is a crucial step in this process. Here we investigate the effect of hepatocyte growth factor (HGF) on the induction of in vitro invasiveness of poorly aggressive Caco-2 colonic cancer epithelial cells. Invasion assays through a Matrigel barrier were performed. Proteases were assessed by zymography, reverse transcription-polymerase chain reaction and immunoblotting. Caco-2 cells were found to express HGF receptor but not HGF and to secrete several proteases, namely matrix metalloproteinase-1 (MMP-1), MMP-2, possibly MMP-9 and urokinase plasminogen activator (uPA). Exogenous HGF promoted invasiveness of Caco-2 cells through an artificial basement membrane matrix and enhanced their production of proteases. In addition, analyses of media at the end of invasion assays indicated that anti-HGF antibody inhibited protease production in parallel with cell invasion. The involvement of proteases in the HGF-induced invasion process was further investigated using either a synthetic general MMP inhibitor or neutralizing antibodies against MMPs or uPA. All components significantly inhibited HGF-promoted cell invasion. Moreover, specific inhibitors of PKCalpha/beta1 and PI3 kinase also decreased both HGF-promoted cell invasion and protease expression in invasion assay media. Thus, our findings provide evidence that the process of HGF-activated invasiveness of Caco-2 cells involves PI3 kinase and PKC and results from close association of two events, stimulation of cell motile activity and concomitant overproduction of proteases, which permits cell migration through a degraded extracellular matrix.
Carcinogenesis 2001 Jul
PMID:Hepatocyte growth factor induces colonic cancer cell invasiveness via enhanced motility and protease overproduction. Evidence for PI3 kinase and PKC involvement. 1140 46

Invasion of malignant tumor cells is required for the formation of metastatic colonies. Uncontrolled expression of matrix metalloproteinase (MMP)-2 and MMP-9 is a critical part of the invasive potential of tumor cells and is affected by the balance between the enzymes and the inhibitors secreted by the cell. Here we analyzed the expression and activity of the two gelatinases (MMP-2 and MMP-9) as well as the expression levels of the tissue inhibitor of metalloproteinase (TIMP2)-, in different stages of carcinogenesis using mouse skin cell lines derived from tumors induced by chemical mutagens. Our results suggested that the expression of MMP-9 was implicated in the progression to spindle cell carcinomas in mouse keratinocytes. MMP-2 levels remained steady in all cell lines, whereas levels of TIMP-2 were increased in normal and spindle cells. The AP-1 DNA binding and transcriptional activity on the MMP-9 promoter were increased in the malignant cell lines, indicating the requirement of this binding site for its activation. The results of this study clearly suggested the important role of MMP-9, but not of MMP-2, in the metastatic properties of mouse keratinocytes.
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PMID:Role of matrix metalloproteinase-9 in progression of mouse skin carcinogenesis. 1142 84

Recent evidence suggests that integrins are involved in the multi-step process of tumour metastasis. The biological relevance of alpha(v) integrins and associated beta-subunits in ovarian cancer metastasis was examined by analysing the expression of these cell surface receptors in nine ovarian cancer cell lines and also in the primary human ovarian surface epithelial cell line (HOSE). beta1, beta3 and beta5 subunits were present in all ten ovarian cell lines. beta6 subunit was present at varying levels in eight out of nine cancer cell lines but was absent in the HOSE cell line. Immunohistochemical staining showed that beta6 was present in both non-invasive (borderline) and high-grade ovarian cancer tissues but was absent in benign and normal ovarian tissue. High alpha(v)beta6 integrin expressing ovarian cancer cell lines had high cell surface expression of uPA and uPAR. Ovarian cancer cell lines expressing high to moderate level of alpha(v)beta6 integrin demonstrated ligand-independent enhanced levels of high molecular weight (HMW)-uPA and pro-matrix metalloproteinase 2 and 9 (pro-MMP-2 and pro-MMP-9) expression in the tumour-conditioned medium. High and moderate expression of alpha(v)beta6 integrin correlated with increased plasminogen-dependent degradation of extracellular matrix which could be inhibited by inhibitors of plasmin, uPA and MMPs or by monoclonal antibody against uPA, MMP-9 or alpha(v)beta6 integrin. These results suggest that endogenous de novo expression of alpha(v)beta6 integrin in ovarian cancer cells may contribute to their invasive potential, and that alpha(v)beta6 expression may play a role in ovarian cancer progression and metastasis.
Carcinogenesis 2002 Feb
PMID:Overexpression of alpha(v)beta6 integrin in serous epithelial ovarian cancer regulates extracellular matrix degradation via the plasminogen activation cascade. 1187 28

Proprotein convertases (PCs) have been implicated in tumor cell invasion by processing a variety of substrates including matrix metalloproteinases (MMPs). PACE4, a member of the family of PCs was shown to enhance mouse skin carcinoma progression by increasing tumor cell invasiveness. However, the effects of PACE4 on malignant conversion have not been investigated. In the present study we address the possible role of PACE4 as a trigger of malignant conversion by transfecting with a full-length PACE4 cDNA, three keratinocyte cell lines with no or little tumorigenic potential, i.e. non-tumorigenic BALB/MK-2 cells, tumorigenic non-invasive MT1/2 cells and tumorigenic moderately invasive p117 mouse skin keratinocytes. Overexpression of PACE4 led to a significant increase in the processing of stromelysin-3, a well-characterized substrate of this PC. When assayed for invasive ability, the PACE4-transfected cells were invasive both in vitro and in vivo, whereas their control counterparts were not. In addition, an enhanced processing ability of MT2-MMP a known substrate of PCs was detected in the PACE4-transfected cells. This was accompanied by MMP-2 and MMP-9 activation in PACE4 transfectants. Invasion and MMP processing were remarkably reduced when PACE4 was inhibited with a specific antibody. By triggering the processing of crucial invasion-related proteases, PACE4 is not only able to enhance the invasive ability of malignant cells as demonstrated previously, but also played a significant role in converting non-invasive keratinocytes into malignant cells.
Carcinogenesis 2002 Apr
PMID:Malignant conversion of non-tumorigenic murine skin keratinocytes overexpressing PACE4. 1196 Sep 7

Matrix metalloproteinases (MMPs) are a family of enzymes involved in degradation of extracellular matrix. An imbalance between MMPs and naturally occurring MMP inhibitors may cause excess extracellular matrix destruction, allowing cancer cells to invade surrounding tissues and metastasize, and permitting angiogenesis to occur. Inhibition of certain key MMPs may prevent angiogenesis, tumor growth, invasion, and metastasis. Gelatinases MMP-2 and MMP-9 are expressed during carcinogenesis and angiogenesis. Synthetic MMP inhibitors were designed to target these enzymes and potentially prevent the tumor growth and metastases associated with cancer.
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PMID:Matrix metalloproteinase inhibitors: do they have a place in anticancer therapy? 1206 62

We employed a genetically defined human cancer model to investigate the contributions of two genes up-regulated in several cancers to phenotypic changes associated with late stages of tumorigenesis. Specifically, tumor cells expressing two structurally unrelated bone-related genes, osteonectin and osteoactivin, acquired a highly invasive phenotype when implanted intracranially in immunocompromised mice. Mimicking a subset of gliomas, tumor cells invaded brain along blood vessels and developed altered vasculature at the brain-tumor interface, suggesting that production of those two proteins by tumor cells may create a complex relationship between invading tumor and vasculature co-opted during tumor invasion. Interestingly, the same tumor cells formed massive spontaneous metastases when implanted subcutaneously. This dramatic alteration in tumor phenotype indicates that cellular microenvironment plays an important role in defining the specific effects of those gene products in tumor behavior. In vitro examination of tumor cells expressing either osteonectin or osteoactivin revealed that there was no impact on cellular growth or death but increased invasiveness and expression of MMP-9 and MMP-3. Specific pharmacologic inhibitors of MMP-2/9 and MMP-3 blocked the increased in vitro invasion associated with osteoactivin expression, but only MMP-3 inhibition altered the invasive in vitro phenotype mediated by osteonectin. Results from this genetically defined model system are supported by similar findings obtained from several established tumor cell lines derived originally from human patients. In sum, these results reveal that the expression of a single bone-related gene can dramatically alter or modify tumor cell behavior and may confer differential growth characteristics in different microenvironments. Genetically defined human cancer models offer useful tools in functional genomics to define the roles of specific genes in late stages of carcinogenesis.
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PMID:Bone-related genes expressed in advanced malignancies induce invasion and metastasis in a genetically defined human cancer model. 1259 Jan 37

The novel mitogen/extracellular-signal-regulated kinase kinase 5/extracellular signal-regulated kinase-5 (MEK5/ERK5) pathway has been implicated in the regulation of cellular proliferation. MEK5 expression has been detected in prostate cancer cells, although the significance of the MEK5/ERK5 pathway in human prostate cancer has not been tested. We examined MEK5 expression in 127 cases of prostate cancer and 20 cases of benign prostatic hypertrophy (BPH) by immunohistochemistry and compared the results to clinical parameters. We demonstrated that MEK5 expression is increased in prostate cancer as compared to benign prostatic tissue. Strong MEK5 expression correlates with the presence of bony metastases and less favourable disease-specific survival. Furthermore, among the patients with high Gleason score of 8-10, MEK5 overexpression has an additional prognostic value in survival. MEK5 transfection experiments confirm its ability to induce proliferation (P < 0.0001), motility (P = 0.0001) and invasion in prostate cancer cells (P = 0.0001). MEK5 expression drastically increased MMP-9, but not MMP-2 mRNA expression. Luciferase report assays suggest that the -670/MMP-9 promoter is upregulated by MEK5 and electromobility shift assay further suggests the involvement of activator protein-I (AP-1), but not the NF-kappa B, binding site in the MMP-9 promoter. Using an AP-1 luciferase construct, activation of MEK5 was confirmed to enhance AP-1 activities up to twofold. Taken together, our results establish MEK5 as a key signalling molecule associated with prostate carcinogenesis. As the MEK5/ERK5 interaction is highly specific, it represents a potential target of therapy.
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PMID:MEK5 overexpression is associated with metastatic prostate cancer, and stimulates proliferation, MMP-9 expression and invasion. 1261 64

Neutrophil gelatinase-associated lipocalin (NGAL) is a novel member of the lipocalin family and may be a new human oncogene product, but function of NGAL is not clear in the cancer. It was recently found that NGAL was overexpressed in the progression of malignant transformation from human immortalized esophageal epithelial cell line SHEE to esophageal carcinoma cell line SHEEC. This indicated that cell line SHEEC was a good model for exploring functions of NGAL in the carcinogenesis. The effects of blocking transcription of NGAL gene on invasion, division and proliferation of SHEEC cells were studied by antisense blocking RNA technique and tumor formation in nude mice. The results showed that the antisense blocking of transcription of NGAL gene not only decreased effectively the activity of MMP-9 and MMP-2 secreted by SHEEC cells, but suppressed significantly also the invasion of these cells in nude mice. However, the telomere length, the content of the cellular topoisomerase II-alpha and cellular proliferation index (PI) of the SHEEC cells have not been changed markedly. These results indicate that NGAL is possibly involved in invasion of tumor cells by regulating activity of MMP-9 and MMP-2, but is not apparently related with division and proliferation of tumor cells in SHEEC.
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PMID:[Functions of neutrophil gelatinase-associated lipocalin in the esophageal carcinoma cell line SHEEC]. 1262 49

Matrix metalloproteinases (MMPs) have the ability to degrade basement membranes and may thus play an important role in extracellular matrix turnover in liver fibrosis and carcinogenesis. Serum levels of MMPs have been suggested as diagnostic markers in these processes. We measured serum MMP-2 and MMP-9 by ELISA in 91 patients with chronic liver disease, including 25 patients with hepatocellular carcinoma (HCC), and in 60 controls. MMP-2 was significantly higher in patients with chronic liver disease compared to controls, and increased with Child-Pugh class. There was a significant correlation between MMP-2 and liver function (bilirubin, albumin, and prothrombin time), and a strong opposite correlation between MMP-9 and these parameters. MMP-2 levels in patients with HCC were significantly higher than in controls, but comparable to patients with chronic liver disease without this malignancy. MMP-9 yielded no significant differences between patients with or without HCC and controls. Serum MMP-2 and to a lesser extent MMP-9 correlate with the severity of liver disease and may reflect changes in extracellular matrix remodeling. Due to a considerable overlap in patients with chronic liver disease with or without HCC, MMP-2 and MMP-9 can not be used as a diagnostic marker for HCC.
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PMID:Assessment of the clinical significance of serum matrix metalloproteinases MMP-2 and MMP-9 in patients with various chronic liver diseases and hepatocellular carcinoma. 1266 27


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