Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0596263 (carcinogenesis)
 64,820 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ultraviolet A (UVA, 315-400 nm), constituting about 95% of ultraviolet irradiation in natural sunlight, represents a major environmental challenge to the skin and is clearly associated with human skin cancer. It has proven difficult to show direct actions of UVA as a carcinogen in human cells. Here, we demonstrate that chronic UVA exposures at environmentally relevant doses in vitro can induce malignant transformation of human keratinocytes associated with acquired apoptotic resistance. As evidence of carcinogenic transformation, UVA-long-treated (24 J/cm(2) once/week for 18 weeks) HaCaT (ULTH) cells showed increased secretion of matrix metalloproteinase (MMP-9), overexpression of keratin 13, altered morphology and anchorage-independent growth. Malignant transformation was established by the production of aggressive squamous cell carcinomas after inoculation of ULTH cells into nude mice (NC(r)-nu). ULTH cells were resistant to apoptosis induced not only by UVA but also by UVB and arsenite, two other human skin carcinogens. ULTH cells also became resistant to apoptosis induced by etoposide, staurosporine and doxorubicin hydrochloride. Elevated phosphorylation of protein kinase B (PKB, also called AKT) and reduced expression of phosphatase and tensin homologue deleted on chromosome 10 (PTEN) were detected in ULTH cells. The resistance of ULTH cells to UVA-induced apoptosis was reversed by either inhibition of phosphatidylinositol 3-kinase (PI-3K) or adenovirus expression of PTEN or dominant negative AKT. These data indicate that UVA has carcinogenic potential in human keratinocytes and that the increased AKT signaling and decreased PTEN expression may contribute to this malignant transformation. Further comparisons between the transformed ULTH and control cells should lead to a better understanding of the mechanism of UVA carcinogenesis and may help identify biomarkers for UVA-induced skin malignancies.
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PMID:Chronic UVA irradiation of human HaCaT keratinocytes induces malignant transformation associated with acquired apoptotic resistance. 1668 58

Trypsin is involved in colorectal carcinogenesis and promotes proliferation, invasion, and metastasis. Although a well-known pancreatic digestive enzyme, trypsin has also been found in other tissues and various cancers, most importantly of the colorectum. Moreover, colorectal cancers with trypsin expression have a poor prognosis and shorter disease-free survival. Biological understanding of how trypsin causes cancer progression is emerging. It seems to act both directly and indirectly through a 'proteinase-antiproteinase-system', and by activation of other proteinase cascades. Invasion of the basal membrane by cancer cells may be promoted directly by trypsin digestion of type I collagen. Trypsin activates, and is co-expressed with matrix metalloproteinases (MMPs), which are known to facilitate invasion and metastasis. MMP-2, MMP-7, and MMP-9 are co-expressed together with trypsin and seem to be of particular importance in proliferation, progression, and invasion. MMPs may play a role in both conversion from adenoma to carcinoma, and in the initiation of invasion and metastasis. Co-segregation of trypsin and MMPs within the tumour environment is important for the activation of MMPs, and may explain the deleterious effect of trypsin on prognosis in colorectal cancer. Trypsin and proteinase-activated receptor 2 (PAR-2) act together in an autocrine loop that promotes proliferation, invasion, and metastasis through various mechanisms, of which prostaglandin synthesis is important. Stimulated by trypsin, both MMP and PAR-2 may activate the mitogenic MAPK-ERK pathway through activation of the epidermal growth factor receptor. Experimental trypsin inhibition is feasible but not very effective, and trypsin as a target for clinical therapy is unlikely to be successful owing to its universal distribution. However, as the pathways of trypsin and co-activated protein cascades emerge, biological understanding of colorectal carcinogenesis will be further illuminated and may pave the way for prognosticators, predictors, and novel targets of therapy.
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PMID:Trypsin in colorectal cancer: molecular biological mechanisms of proliferation, invasion, and metastasis. 1669 44

One of the most frequent events in carcinogenesis is uncontrolled activation of Ras signaling pathway. A previous study demonstrated that the introduction of H-Ras into the normal WB-F344 rat liver epithelial (WB) cell line and adult male F344 rats resulted in tumorigenicity. The present study investigated whether H-Ras induced the invasive and migrative phenotypes in WB cells, and subsequently aimed at characterizing the underlying mechanisms. H-Ras induced the invasive and migrative phenotypes of WB cells with a selective up-regulation of matrix metalloproteinase (MMP)-9, but not MMP-2. Cyclooxygenase (COX)-2 and the subsequent production of prostaglandin E2 (PGE2) were also induced by H-Ras. Treatment of H-Ras WB cells with GM6001 and NS398, the inhibitors of MMPs and COX-2, respectively, significantly inhibited the H-Ras-induced invasive and migrative phenotypes. DNA binding activity of nuclear factor (NF)-kappaB, but not that of activator protein (AP)-1, was increased by H-Ras. Caffeic acid phenethyl ester and Bay 11-7082, specific inhibitors of NF-kappaB and IKK, respectively, significantly inhibited the expression of MMP-9 and COX-2, invasion and migration of H-Ras WB cells, revealing NF-kappaB as a transcriptional factor responsible for H-Ras-induced malignant phenotypic conversion of WB cells. Activation of ERKs pathway was critical for H-Ras-induced invasive and migrative phenotypes, up-regulation of MMP-9 and COX-2 as well as enhanced DNA binding activity of NF-kappaB in WB cells. Taken together, these results demonstrate that H-Ras up-regulates MMP-9 and COX-2 through activation of ERKs and IKK-IkappaBalpha-NF-kappaB signal pathway which may contribute to the malignant progression of WB rat liver epithelial cells.
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PMID:H-Ras selectively up-regulates MMP-9 and COX-2 through activation of ERK1/2 and NF-kappaB: an implication for invasive phenotype in rat liver epithelial cells. 1672 10

It has been well established that the restoration of connexin expression in tumor cells often leads to a partial reversion of tumor cell phenotypes and increased growth control. In this study, a less-aggressive variant of MDA-MB-435 cells obtained from the MDA-MB-435 cell line was engineered to express gap junctional intercellular communication (GJIC)-competent Cx26, a GJIC-incompetent cell surface transported GFP-Cx26 chimera, or a Golgi apparatus-localized, disease-linked Cx26 mutant (D66H). Collectively, these cell lines were designed to establish whether Cx26 regulates tumor properties, such as migration, invasion and growth, by (i) a GJIC-dependent pathway; (ii) a mechanism requiring Cx26 transport to the cell surface; or (iii) a mechanism where Cx26 expression alone was sufficient. The expression of Cx26 and green fluorescent protein (GFP)-Cx26 decreased cell proliferation while all three Cx26 variants inhibited anchorage-independent cell growth. All three Cx26 variants also altered the distribution of filamentous actin and significantly reduced cell migration, while only the D66H mutant failed to inhibit cell invasion through matrigel. Furthermore, expression of all the Cx26 variants reduced the levels of total beta1 integrin, and decreased the activity of matrix metalloproteinase-9 (MMP-9) while increasing tissue inhibitors of MMP-1 (TIMP-1) activity. Interestingly, the expression of Cx43 regulated the same gene products without significantly affecting the tumorigenic properties of the MDA-MB-435 cells. Together, these results suggest that Cx26 expression, independent of the necessity for gap junctional intercellular communication, partially reverted MDA-MB-435 cell properties associated with tumorigenesis, and regulated the expression of genes important in cell migration and invasion.
Carcinogenesis 2006 Dec
PMID:Cx26 inhibits breast MDA-MB-435 cell tumorigenic properties by a gap junctional intercellular communication-independent mechanism. 1677 86

The recent elucidation both of the mechanisms involved in pancreatic cancer carcinogenesis and the related molecular events, has led to several distinct therapeutic advances, including many novel target agents, such as monoclonal antibodies against EGFR, EGFR-tyrosine kinase inhibitors, monoclonal antibody against VEGF, farnesyl transferase inhibitors, matrix metalloproteinase inhibitors, COX 2 inhibitors, and the development of gene therapy to target pancreatic cancer. This review highlights recent findings in the treatment of pancreatic cancer by using these novel therapeutic approaches.
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PMID:New target therapies in advanced pancreatic cancer. 1680 45

Colorectal carcinogenesis is initiated mainly by aberrant activation of the Wnt signaling pathway, caused by mutation of either APC or beta-catenin (CTNNB1) gene. Poly(ADP-ribose) polymerase-1 (PARP-1) is a highly conserved nuclear enzyme, which binds tightly to DNA and plays a role in DNA repair, recombination, proliferation and genomic stability. It has recently been shown that PARP-1 is a novel co-activator of TCF-4/beta-catenin-evoked gene transactivation and may play a role in colorectal carcinogenesis. The aim of this study was to examine the PARP-1 expression and determine whether it is correlated with the expression of beta-catenin and its target genes such as c-myc, cyclin D1 and matrix metalloproteinase (MMP)-7 in the early stage of sporadic colorectal carcinogenesis. Using the semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), 91 colorectal tumours, including 65 adenomas and 26 submucosal (pT1) cancers, were analysed for the expression of PARP-1, beta-catenin, c-myc, cyclin D1 and MMP-7. Immunohistochemical analysis of PARP-1 and beta-catenin was also performed. PARP-1 mRNA overexpression was detected in 64 (70.3%) of the 91 tumours. PARP-1 overexpression was significantly correlated with tumour size and histopathology. Overexpression of beta-catenin, c-myc, cyclin D1 and MMP-7 mRNA expression was observed in 39.6%, 78.0%, 83.5% and 72.5% of the 91 tumours, respectively. PARP-1 overexpression was correlated significantly with overexpression of beta-catenin, c-myc, cyclin D1 and MMP-7. Correlation of PARP-1 expression with beta-catenin overexpression was also demonstrated by immunohistochemistry. The results suggest that PARP-1, in conjunction with beta-catenin, c-myc, cyclin D1 and MMP-7, plays an important role in the early stage of colorectal carcinogenesis.
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PMID:Overexpression of poly(ADP-ribose) polymerase-1 (PARP-1) in the early stage of colorectal carcinogenesis. 1680 31

Epilysin (MMP-28) is the newest member of the matrix metalloproteinase (MMP) family. Although it is expressed in a number of tissues, no biological substrates or functions for this enzyme have been identified yet. We have expressed recombinant epilysin in A549 lung adenocarcinoma cells and found that this resulted in stable and irreversible epithelial to mesenchymal transition (EMT) accompanied by loss of cell surface E-cadherin, proteolytic processing of latent TGF-beta-complexes and increased levels of active TGF-beta. The cascade of events leading to the onset of EMT is prevented by the MMP inhibitor GM6001 or antibodies neutralizing the activity of TGF-beta. Once EMT had occurred the cell phenotype could, however, not be reversed by the MMP-inhibitor. Importantly, the expression of epilysin also resulted in upregulation of MT1-MMP and gelatinase-B (MMP-9) and in the collagen invasive activity of A549 cells. Further, we found that epilysin and the recombinant hemopexin domain were targeted to the surface of epithelial cells. This cell surface interaction was sensitive to the proteolytic activity of MT1-MMP, and was lost after EMT. Current results indicate that epilysin can induce EMT and cell invasion through a TGF-beta-dependent mechanism suggesting novel biological roles for this enzyme in the regulation of epithelial cell function and in the induction of carcinogenesis.
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PMID:Epilysin (MMP-28) induces TGF-beta mediated epithelial to mesenchymal transition in lung carcinoma cells. 1694 Mar 49

T-cell factor (TCF)-1 protein forms the transcriptional complex with beta-catenin and regulates the expression of diverse target genes during early development and carcinogenesis. We have selected previously an RNA aptamer that binds to the DNA-binding domain of TCF-1 and have shown that it interfered with binding of TCF-1 to its specific DNA recognition sequences in vitro. As an approach to modulate the transcription by TCF/beta-catenin complex in the cells, we have developed the RNA expression vector for stable expression of RNA aptamer inside of the mammalian cells. High level of RNA was expressed as an intramer in the fusion with the stable RNA transcript. The RNA intramer inhibited TCF/beta-catenin transcription activity as shown by luciferase assay. It also modulated the expression of TCF/beta-catenin target genes, such as cyclin D1 and matrix metalloproteinase-7, as predicted to be as an effective inhibitor of the TCF function. In addition, it efficiently reduced the growth rate and tumorigenic potential of HCT116 colon cancer cells. Such RNA intramer could lead to valuable gene therapeutics for TCF/beta-catenin-mediated carcinogenesis.
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PMID:Intracellular expression of the T-cell factor-1 RNA aptamer as an intramer. 1698 77

Prostate cancer, the most commonly diagnosed cancer among American men, develops slowly over many years. The long latent period of 20 to 30 years, involved in the multistep process of carcinogenesis, provides an important opportunity to block or reverse progression to a malignant state. Vitamin A (retinoids) and vitamin D not only have the ability to block steps in the process of carcinogenesis but they can also modulate or reverse some malignant characteristics of cancer cells. However, at high levels, vitamins A and D have undesirable side effects, thus, limiting effective dose levels and efficacy. Therefore, combination treatment at low doses, to increase efficacy and avoid toxicity, is of special interest. This study examines the effects of the synthetic retinoid N-(4-hydroxyphenyl)retinamide (4-HPR) in combination with cholecalciferol (vitamin D3) on growth, and on the expression of vimentin, matrix metalloproteinase-2 (MMP-2), and retinoid and vitamin D receptor expression, using the non-tumorigenic, human prostate epithelial cell line RWPE-1. Treatment with 4-HPR and cholecalciferol resulted in synergistic growth inhibition when compared to that caused by each agent alone. A decrease in vimentin expression and MMP-2 activity, and up-regulation of vitamin D receptor (VDR) and some of the retinoid-X (RXRs) and retinoic acid receptor (RARs) subtypes, was observed. These results suggest that combined treatment with 4-HPR and cholecalciferol, at doses lower than what might be effective with single agents, increases their efficacy and suggest that this may serve as an effective strategy for chemoprevention and treatment of prostate cancer.
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PMID:Cholecalciferol (vitamin D3) and the retinoid N-(4-hydroxyphenyl)retinamide (4-HPR) are synergistic for chemoprevention of prostate cancer. 1702 72

The expression of matrix metalloproteinase-9 (MMP-9) has been implicated in the invasion and metastasis of cancer cells. Here, we found that an antitumor antibiotic, ascofuranone, inhibits invasion and MMP-9 induction induced by phorbol myristate acetate (PMA) in human cell lines. Ascofuranone also inhibits the protein expression and transcription of MMP-9 induced by tumor necrosis factor-alpha. The inhibition of MMP-9 induction was observed in human cancer cell lines as well as primary rat mesangial cells. Furthermore, as evidenced by MMP-9 promoter and electrophoretic mobility shift assays, ascofuranone specifically inhibited MMP-9 gene expression by blocking PMA-stimulated activation of activator protein-1 (AP-1). In addition, ascofuranone suppressed PMA-induced phosphorylation of Ras, Raf, MEK and extracellular signal-regulated kinase (ERK), upstream factors involved in AP-1activation, whereas the phosphorylation of p38 and JNK/mitogen-activated protein kinase was not affected by ascofuranone, suggesting that the primary target of ascofuranone for suppression of the AP-1 induction is present in upstream of ERK signaling pathway. These results suggest that the suppression of MMP-9 expression, at least in part, contributes to the antitumor activity of ascofuranone.
Carcinogenesis 2007 May
PMID:Ascofuranone suppresses PMA-mediated matrix metalloproteinase-9 gene activation through the Ras/Raf/MEK/ERK- and Ap1-dependent mechanisms. 1711 44


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