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

Lung cancer is the leading cause of malignancy-related mortality in the U.S. and is predicted to increase over the remainder of this decade. Despite attempts to advance early diagnosis and use combination therapies, the clinical response of this cancer yields an overall 5-year survival rate of less than 15%. Clearly, new strategies for therapy are indicated. Although carcinogenesis is complex, tumor growth beyond 1-2 mm3 is dependent on angiogenesis. One of the potential mechanisms that allows for tumorigenesis is dysregulation of the balance of angiogenic and angiostatic factors that favors net neovascularization within the primary tumor. Numerous studies have investigated the role of a variety of molecules in the regulation of angiogenesis. Recently, interleukin-8 (IL-8), a member of the C-X-C chemokine family, has been found to be an angiogenic factor. In contrast, platelet factor 4 (PF4), another C-X-C chemokine, has been shown to have angiostatic properties. It is interesting that the major structural difference between IL-8 and PF4 is the presence of the NH2-terminal ELR (Glu-Leu-Arg) motif that precedes the first cysteine amino acid residue of IL-8 and is important in ligand/receptor interactions. We hypothesize that angiogenesis associated with tumorigenesis is dependent on members of the C-X-C chemokine family acting as either angiogenic or angiostatic factors. This paradigm predicts that the biological balance in the expression of these C-X-C chemokines dictates whether the neoplasm grows and develops metastatic potential or regresses. In this review we discuss our recent laboratory findings that support this contention and suggest that further elucidation of the biology of C-X-C chemokines in the context of neovascularization of nonsmall cell lung cancer will permit novel targeted therapy aimed specifically at attenuating tumor growth and metastasis.
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PMID:Role of C-X-C chemokines as regulators of angiogenesis in lung cancer. 753 29

Given the associations between chronic inflammation and epithelial cancer, we studied susceptibility to skin carcinogenesis in mice deficient for the pro-inflammatory cytokine TNF-alpha (refs. 5,6). TNF-alpha(-/-) mice were resistant to development of benign and malignant skin tumors, whether induced by initiation with DMBA and promotion with TPA or by repeated dosing with DMBA. TNF-alpha(-/-) mice developed 5-10% the number of tumors developed by wild-type mice during initiation/promotion and 25% of those in wild-type mice after repeated carcinogen treatment. TNF-alpha could influence tumor and stromal cells during tumor development. The early stages of TPA promotion are characterized by keratinocyte hyperproliferation and inflammation. These were diminished in TNF-alpha(-/-) mice. TNF-alpha was extensively induced in the epidermis, but not the dermis, in TPA-treated wild-type skin, indicating that dermal inflammation is controlled by keratinocyte TNF-alpha production. Deletion of a TNF-alpha inducible chemokine also conferred some resistance to skin tumor development. TNF-alpha has little influence on later stages of carcinogenesis, as tumors in wild-type and TNF-alpha(-/-) mice had similar rates of malignant progression. These data provide evidence that a pro-inflammatory cytokine is required for de novo carcinogenesis and that TNF-alpha is important to the early stages of tumor promotion. Strategies that neutralize TNF-alpha production may be useful in cancer treatment and prevention.
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PMID:Mice deficient in tumor necrosis factor-alpha are resistant to skin carcinogenesis. 1039 30

Interleukin-8 (IL-8) is a chemokine for neutrophils and an angiogenic factor. Human tumors that express IL-8 may exhibit intense neutrophil infiltration and increased vascularization. Mutatect cells are a murine fibrosarcoma that can be grown as subcutaneous tumors in syngeneic C57BL/6 mice. Since neutrophils are a source of cytotoxic and genotoxic species, we constructed Mutatect cell lines that constitutively express human IL-8 to explore the involvement of neutrophils in tumor biology and genetic instability. An IL-8/neo expression plasmid was stably transfected into Mutatect MC17-51 cells and clone MIL-4 was isolated. Tumors initiated with 5x10(5) MIL-4 cells grew very slowly compared with tumors from pure MC17-51 cells or from 0.5 to 4x10(5) MIL-4 cells mixed with 5x10(5) MC17-51 cells. Over 95% of cells recovered from slow-growing pure MIL-4 tumors lost the transgene as measured by loss of (i) resistance to G418, (ii) expression of IL-8 protein and (iii) IL-8-specific DNA sequences. When tumors from mixed cell types were examined, loss of the transgene did not occur; rather, IL-8 producing cells appeared to have some growth advantage. The neutrophil content of tumors (as measured by myeloperoxidase) was directly proportional to the level of IL-8 expressed at the time tumors were excised. As reported earlier, the frequency of mutations at the hypoxanthine phosphoribosyltransferase locus was also directly proportional to neutrophil content. To explain some of these biological findings, we postulate that early in development of pure MIL-4 tumors, genotoxic/cytotoxic neutrophils are attracted by IL-8, which in turn leads to loss of the transgene and to localized cytotoxicity of IL-8 producing cells. In mixed tumors, where the initial IL-8 concentration may be lower, tumors might become established more readily because fewer neutrophils may be attracted. This relatively simple experimental paradigm has revealed some of the complex biological changes that can occur as a result of IL-8 in tumors.
Carcinogenesis 2001 Feb
PMID:Constitutive expression of interleukin-8 by Mutatect cells markedly affects their tumor biology. 1118 44

The beta-chemokine RANTES was measured in plasma in 43 patients with breast cancer and in 23 patients with cervical cancer, and the RANTES content in primary tumors, tumor metastatic to lymph nodes, and clinically normal skin or pelvic mucosa was measured. In addition, plasma levels were determined in all of the patients for the platelet-derived chemokine beta-thromboglobulin (beta-TG) and for IFN-gamma, interleukin (IL)-2, IL-4, IL-5, and IL-10, along with serum IgE levels and blood eosinophils. Plasma RANTES levels were found to be higher in order of stages IV, III, II, and I of each cancer except for stage I. A marked increase in plasma RANTES level (> 10,000 pg/ml) was found in 27% of patients with progressive malignancy but in none of those in clinical remission. The platelet RANTES content was correspondingly decreased in those patients with increased plasma RANTES levels. Beta-TG showed a pattern similar to RANTES both in plasma and platelets, but with much less dramatic differences between patients with different stages of disease. Other allergic parameters, IgE, eosinophils and plasma IFN-gamma, IL-2, -5, and -10, were not elevated in the cancer patients. The RANTES content was markedly elevated in the primary tumor and metastatic lesions (lymph node or skin) from all of the patients with breast or cervical cancer, irrespective of the plasma RANTES level. In addition, in patients with progressive breast or cervical cancer, but not in patients thought to be cured of these tumors, the RANTES content was markedly increased in clinically normal tissue taken from near the operative site several months postoperatively, as well as in intact skin or mucosa taken perioperatively near the excised tumor. This study suggests an as-yet-undefined but important role played by RANTES in carcinogenesis, as well as the possibility that a RANTES assay in tissue surrounding a tumor or postoperative tumor site may help predict prognosis in these patients.
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PMID:Correlation of tissue and plasma RANTES levels with disease course in patients with breast or cervical cancer. 1123 81

Chemokines represent a family of low molecular weight secreted proteins that primarily function in the activation and migration of leukocytes. A number of additional functions of chemokines have also been identified including growth of tumor cells, angiogenesis and development. An iterative search for new chemokines has identified a cDNA that encodes a new member of the CC(beta) chemokine family. The gene has been named MEC, for mammary enriched chemokine. MEC expression was found at high levels in many mammary gland samples and was also detected at lower levels in several other epithelial-enriched tissues, such as salivary gland, colon, and prostate. Northern blot analysis demonstrates that MEC expression was highly reduced or eliminated in a majority of human breast tumors as compared to normal adjacent tissue. In situ hybridization demonstrates that MEC was abundantly expressed in normal mammary ductal epithelium, but expression was absent or reduced in various mammary tumor types of epithelial origin. These observations suggest that MEC may be useful as a diagnostic tool in oncology, and may play a role in regulating mammary carcinogenesis. The absence of MEC may also contribute to the host's immune response to tumors.
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PMID:Identification of a novel beta-chemokine, MEC, down-regulated in primary breast tumors. 1129 38

Macrophage inflammatory protein (MIP-3alpha) is a CC chemokine that attracts immature dendritic cells and lymphocytes and is thought to play a role in the pathogenesis of inflammation and carcinogenesis. However, nothing is known about the clinical significance or prognostic importance of this chemokine in patients with cancer. The aim of this study was to assess the clinical factors influencing the levels of serum MIP-3alpha and to evaluate any possible prognostic importance of this chemokine. We further checked the possible source of MIP-3alpha in hepatocellular carcinoma (HCC). The levels of serum MIP-3alpha from 45 patients with HCC, 12 patients with liver cirrhosis (LC) and 45 patients with chronic hepatitis (CH) were measured by an enzyme immunoassay. A correlationship between different clinical parameters and the serum levels of MIP-3alpha was analyzed. Production of MIP-3alpha by human cancer cell lines and peripheral blood mononuclear cells (PBMC) was also estimated. The levels of serum MIP-3alpha were significantly higher in HCC than in LC (p=0.0214) and CH (p<0.0001). Cancer-related factors such as size of cancer nodules, levels of differentiation of HCC and the levels of alpha-fetoprotein were related with increased MIP-3alpha levels in HCC. Human cancer cell lines, but not PBMC from HCC patients, produced very high levels of MIP-3alpha in culture. The rate of recurrence of HCC after radio frequency ablation (RFA) was fewer in patients having lower pre-therapeutic levels of serum MIP-3alpha. An impact of cancer-related factors on the levels of serum MIP-3alpha in HCC is shown. Pre-therapeutic levels of serum MIP-3alpha may be used as a marker of prognosis of RFA therapy.
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PMID:Increased serum levels of macrophage inflammatory protein-3alpha in hepatocellular carcinoma: relationship with clinical factors and prognostic importance during therapy. 1268 96

Semaphorins are a large family of membrane-bound and secreted molecules involved in numerous functions, including axon guidance, morphogenesis, carcinogenesis, and immunomodulation. A growing number of semaphorins--namely, human CD100/SEMA4D, CD108/SEMA7A, and SEMA3A; viral semaphorins, SemaVA and SemaVB; and, very recently, mouse Sema4A--were reported to regulate immune cell responses. Among them, the role of CD100 has been well documented in both humans and mice. CD100, in particular, has been shown to influence monocyte migration, T-cell activation, B-cell survival as well as T/B and T/dendritic cell cooperation. In contrast to other semaphorins, CD100 is the only semaphorin for which membrane and soluble forms are endowed with functional properties, and for which bidirectional signaling has been suggested. The human membrane-bound CD100 engagement triggers costimulatory signals to T cells through its interaction with membrane protein tyrosine phosphatase CD45 and an intracellular serine kinase. Its soluble extracellular region acts most likely through its receptors, human PlexinB1 and mouse CD72, to promote T-cell priming, B-cell survival and antibody production in response to T-dependent antigens. Human soluble CD100 also induces monocyte paralysis and the arrest of its spontaneous and chemokine-induced migration by signaling through an as yet unknown receptor that is different from PlexinB1 and CD72. In this review, we discuss recent advances in research studies on human and murine CD100, and we describe the relationship of CD100 function to its expression and structure. The signaling events that support CD100 function are also discussed.
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PMID:Structure and function of the immune semaphorin CD100/SEMA4D. 1290 60

Oxidant-sensitive transcription factors, nuclear factor-kappaB (NF-kappaB), and activator protein-1 (AP-1) have been considered as the regulators of inducible genes such as chemokines. Since oxygen radicals are considered as an important regulator in the pathogenesis of Helicobacter pylori (H. pylori)-induced gastric ulceration and carcinogenesis, chemokines such as interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) may be regulated by NF-kappaB and/or AP-1. Ras, the upstream activator for mitogen-activated protein kinase (MAPK) and MAPK cascade regulate AP-1 activation. The present study aims to investigate whether H. pylori in a Korean isolate (HP99) induces the expression of chemokines (IL-8, MCP-1), which is regulated by Ras, MAPK, AP-1, and NF-kappaB in gastric epithelial AGS cells, and whether these transcriptional regulations of chemokines are inhibited by transfection with mutant genes for Ras (ras N-17), c-Jun (TAM-67), and IkappaBalpha (MAD-3) or treatment with MAPK inhibitors (U0126 for extracellular signal-regulated kinase or SB203580 for p38 kinase). In addition, virulence factors of HP99 were characterized by PCR analysis for the isolated DNA. As a result, HP99 is identified as cagA+, vacA s1b, m2, iceA1 H. pylori strain. HP99 induced a time-dependent expression of mRNA and protein for IL-8 and MCP-1 via mediation of MAPK, AP-1, and NF-kappaB. Transfection with mutant genes for Ras, c-Jun, and IkappaBalpha and treatment with MAPK inhibitors suppressed H. pylori-induced activation of transcription factors (NF-kappaB, AP-1) and expression of chemokines (IL-8, MCP-1) in AGS cells. In conclusion, Ras and MAPK cascade may act as the upstream signaling for the activation of AP-1 and NF-kappaB, which induce chemokine expression in H. pylori-infected AGS cells. Specific targeting of the activation of NF-kappaB and AP-1 may be effective for the prevention or treatment of gastric inflammation associated with H. pylori infection.
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PMID:Helicobacter pylori in a Korean isolate activates mitogen-activated protein kinases, AP-1, and NF-kappaB and induces chemokine expression in gastric epithelial AGS cells. 1463 83

Tumour cells naturally secrete proinflammatory cytokines and chemokines to interact with the microenvironment and regulate neoangiogenesis. The repertoire of factors thus produced shapes tumour progression. However, experiments in the mouse have shown that injection of a low pharmacological dose of a proinflammatory cytokine or chemokine into the microenvironment increases the inflammatory reaction so enormously that locally activated leukocytes inhibit or eradicate the tumour. Massive shrinkage of recurrent head and neck squamous cell carcinomas (SCC) and prevention of recurrences after surgical removal of a primary SCC follow perilymphatic administration of low doses of interleukin (IL)2, while low daily doses of IL12 markedly delay carcinogenesis in transgenic mice predestined to die of mammary carcinomas and keep them tumour-free for long periods. The reaction elicited by proinflammatory cytokines evidently has a great potential in tumour control.
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PMID:Proinflammatory cytokines, immune response and tumour progression. 1502 85

The chemokine monocyte chemoattractant protein (MCP)-1 is thought to be involved in breast carcinogenesis. We evaluated MCP-1 serum levels in patients with breast cancer (n = 135), ductal carcinoma in situ (DCIS) I-III (n = 30), benign breast lesions (n = 143) and in healthy women (n = 27). We determined the value of MCP-1 serum levels as a differentiation marker between malignant, preinvasive and benign breast diseases and as a predictive marker for the biological phenotype of breast carcinoma. Median (range) MCP-1 serum levels in patients with breast cancer, DCIS I-III, benign breast lesions and healthy women were 200 (57-692) pg/ml, 194 (58-525) pg/ml, 174 (39-529) pg/ml and 175 (67-425) pg/ml, respectively. No differences were ascertained between the patient groups. In patients with breast cancer, increased MCP-1 serum levels were correlated with advanced tumor stage (p = 0.04) and lymph node involvement (p = 0.04). We were not able to establish MCP-1 as a differentiation marker between malignant and benign breast diseases. Our data might indicate that MCP-1 influences breast carcinogenesis by facilitating tumor growth and metastatic spread, thus altering the biological phenotype of the disease.
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PMID:Monocyte chemoattractant protein-1 serum levels in patients with breast cancer. 1519 7


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