Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0699790 (colon cancer)
 28,837 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A simplified method to quantitatively analyze the migration and proliferation capacity of a colonic cancer cell line (SW837) in vitro was developed. The objective of this study was to evaluate the role of the extracellular matrix in colon cancer metastasis. We used this model to investigate the effects of the extracellular matrix components collagen type I and type IV, laminin, and fibronectin on the migration and the proliferation of cancer cells. Migration was fastest on laminin and slowest on collagen type I. Further, proliferation was highest on laminin of all extracellular matrices groups studied. Therefore, it is concluded that laminin had pronounced effects on migration and proliferation of SW837 cells. These findings suggest that the composition of the extracellular matrix plays an important role in the mechanism of metastasis of colon cancer cells.
 ...
PMID:Role of extracellular matrix on colonic cancer cell migration and proliferation. 864 8

Low tumor uptake and normal tissue toxicity limit the efficacy of RIT for the treatment of solid tumors. In this study, an intratumoral injectable gel drug delivery system for local administration of RIT was evaluated using the LS174T human colon cancer xenograft model in SCID mice. The injectable gel is a collagen-based drug delivery system designed for intratumoral (i.t.) administration, which has previously been shown to enhance drug retention at the injection site and reduce systemic drug exposure. We compared the local (tumor) retention and biodistribution of 111In-labeled NR-LU-10 monoclonal antibody given i.t. in the injectable gel versus simple aqueous solution. 111In gel given i.t. and 111In-NR-LU-10 given intraperitoneally (i.p.) were used as controls. The results showed that tumors treated with 111In-NR-LU-10 gel maintained the highest levels of radioactivity for up to 96 h. At 48 h after the administration of 111In-NR-LU-10 gel i.t., 111In-NR-LU-10 solution i.t., 111In gel i.t., or 111In-NR-LU-10 i.p., the level of radioactivity remaining in each gram of tumor was 98, 49, 45, and 16% of the injected dose, respectively. It was estimated that if 100 microCi of 90Y-NR-LU-10 were administered similarly, tumor treated with 90Y-NR-LU-10 gel i.t. would receive a dose of 90.0 Gy, whereas normal tissues in the same animal would receive a dose of approximately 2.43 Gy. In contrast, if 90Y-NR-LU-10 were delivered i.p., a comparable tumor would receive a dose of 16.8 Gy and corresponding normal tissues would receive 3.36 Gy. Consistent with these estimates, enhanced antitumor efficacy was observed when 90Y-NR-LU-10 gel was administered i.t. Tumor growth delay time was 6.9-fold (P < 0.01) longer in these animals (14.4 days) than in animals treated with 90Y-NR-LU-10 i.p. (2.1 days). Systemic toxicity was also significantly reduced in gel-treated animals as monitored by loss of body weight. This study demonstrated that intratumoral delivery of 90Y-NR-LU-10 gel markedly increased the retention of the radioisotope in tumors, enhanced the antitumor efficacy, and reduced systemic toxicity compared to systemic administration of the radiolabeled antibody. This injectable gel drug delivery system may allow for improvement in the therapeutic index for RIT.
 ...
PMID:Intratumoral radioimmunotherapy of a human colon cancer xenograft using a sustained-release gel. 873 85

Binding of colon cancer to extracellular matrix (ECM) proteins and mesenchymal cells that comprise the basement membrane is important in migration and metastasis. This study defines the conditions and surface structures necessary for adhesion of HT-29 cells to ECM proteins and cell monolayers. Binding began within minutes and peaked by 1 hr, with 80-95% of HT-29 cells binding to the ECM proteins, collagen IV, laminin, fibronectin, and vitronectin and 40-75% binding to monolayers of fibroblasts, smooth muscle cells, and HT-29 cells. Treating mesenchymal cells with the fibrogenic cytokines, IL-1, IL-4, or TNF-alpha, which increase production of ECM proteins, did not alter binding of HT-29 cells to these monolayers. Attachment of HT-29 cells to cell monolayers was inhibited by cytochalasin D and sodium azide, but not cycloheximide or neuraminidase. Attachment to ECM proteins, in contrast, was unaffected by any of these metabolic inhibitors but required certain divalent cations (Mg2+ and Mn2+ but not Ca2+). Antibody to the integrin beta 1, chain (CD29) eliminated binding to collagen and laminin but not to fibronectin, fibroblasts, and HT-29 monolayers. Antibody to the vitronectin receptor inhibited binding to fibronectin. Antibodies to integrin alpha 1-alpha 6 chains had no effect on any adhesion event. Three colon cancer cell lines were tested for expression of VLA antigens: alpha 2 and alpha 3 were detected on all three, alpha 1 and alpha 6 were variably expressed, while alpha 4 and alpha 5 were absent. This study demonstrates that several mechanisms account for tumor cell attachment to substratum and cells.
 ...
PMID:Mechanisms of colon cancer binding to substratum and cells. 876 78

In the normal colon, myofibroblasts are closely apposed to colonocytes where they deposit type IV collagen, the main basement membrane component. In colon carcinomas, this epithelial-mesenchymal association is physically disrupted, leading to the production of an abnormal, type IV collagen defective, basement membrane. Tumor-infiltrating myofibroblasts are migratory cells that accumulate at the invasive front of the colorectal carcinomas. They produce lytic enzymes able to degrade the basement membrane surrounding tumor glands. They also participate in the synthesis of the extracellular matrix components of the tumor stroma, which could subsequently alter the adhesive and migratory properties of the epithelial colon cancer cells. These results suggest that tumor-infiltrating myofibroblasts play a role in the invasion and metastasis of colorectal tumor cells.
 ...
PMID:Role of stromal myofibroblasts infiltrating colon cancer in tumor invasion. 888 Aug 72

Tumor spread may be favored by a reduced production and/or an enhanced degradation of extracellular matrix components (collagen, fibronectin, laminin). Most tumor cell behavior, from growth to spread, may be regulated by cytokines, the exact roles of which, however, are not yet fully understood. We here evaluate the effects of some cytokines (epidermal growth factor, transforming growth factor-beta 1, interleukin-1 alpha, and interleukin-1 beta) on both cell growth and the production of the aminoterminal peptide of type III procollagen, the urokinase plasminogen activator, and the plasminogen activator inhibitor-1 in neoplastic cell lines originating in the pancreas and colon. Cells were stimulated daily with the above cytokines and the aminoterminal peptide of type III procollagen, urokinase plasminogen activator, and plasminogen activator inhibitor-1 were measured in the conditioned media. Epidermal growth factor stimulated cell growth of both cell lines. Transforming growth factor-beta 1 counteracted cell proliferation and stimulated type III procollagen and plasminogen activator inhibitor-1 production only in the colon cancer cell line. Interleukin-1 alpha slightly stimulated cell growth, but inhibited plasminogen activator inhibitor-1 production in both cell lines; interleukin-1 beta did not affect cell growth, but stimulated plasminogen activator inhibitor-1 production by the colon cancer cell line. Our findings suggest that transforming growth factor-beta 1 and interleukin-1 beta may have an antidiffusive effect. These results confirm that cytokine-producing cells have a potential role in stimulating or counteracting tumor growth and spread and also confirm the pivotal role of host-tumor interactions in determining the outcome of a particular neoplasia.
 ...
PMID:Cytokines may influence tumor growth and spread. An in vitro study in two human cancer cell lines. 900 14

Little is known about the the signalling pathways driving the adenoma-to-carcinoma sequence in human colonic epithelial cells. Accumulation and activation of the src tyrosine kinase in colon cancer suggest a potential role of this oncogene in this early progression. Therefore, we introduced either activated src (m-src), polyoma-MT alone or combined with normal c-src in the adenoma PC/AA/C1 cell line (PC) to define the function and phenotypic transformations induced by these oncogenes in familial adenomatous polyposis (FAP) colonic epithelial cells. Functional expression of these oncoproteins induced the adenoma-to-carcinoma conversion, overexpression of the hepatocyte growth factor (HGF) receptor Met, but failed to confer invasiveness in vivo and in vitro, or to produce alterations in cell proliferation and differentiation. In contrast, PC-msrc cells became susceptible to the HGF-induced invasion of collagen gels and exhibited sustained activation of the pp60src tyrosine kinase and Tyr phosphorylation of the 120-kDa E-cadherin, which was further increased by HGF Transcripts of HGF were clearly identified by reverse transcription-polymerase chain reaction (RT-PCR) and Southern blot in the parental and transformed PC cells, suggesting an autocrine mechanism. Taken together, the data indicate that: (1) experimental activation of src and PyMT pathways directly induces tumorigenicity and Met upregulation in a colon adenoma cell line; (2) HGF-activated Met and src cooperate in inducing invasion; (3) in view of the molecular associations between catenins and cadherin or the tumour-suppressor gene product APC, the cell adhesion molecule E-cadherin may constitute a downstream effector of src and Met.
 ...
PMID:Progression of familial adenomatous polyposis (FAP) colonic cells after transfer of the src or polyoma middle T oncogenes: cooperation between src and HGF/Met in invasion. 901 33

A transforming growth factor beta1 (TGF beta1) antisense expression plasmid under constitutive control of the Rous sarcoma virus promoter was introduced into the highly tumorigenic and invasive colon carcinoma U9A cell line, which uses its autocrine TGF beta1 as a growth-stimulating factor. Stable transfectants were infrequent, and only the K6 transfectant exhibited 39 and 33%, respectively, of the levels of TGF beta1 mRNA and active, secreted TGF beta1 protein of the parental line. K6 exhibited no change in TGF beta2 expression, and TGF beta3 expression was not detected in either parental or transfectant cells. Compared to the parental line, the K6 antisense transfectant exhibited a 3-fold increase in lag time in anchorage-dependent colony formation. The parental line was 44 times as invasive through a collagen l-coated polycarbonate membrane in vitro as K6 cells and, after s.c. injection at low-cell inocula, U9A cells induced tumors 75 times as large in vivo as did the K6 antisense transfectant. The decreases in in vitro invasion and anchorage-dependent colony formation seen in K6 cells were largely reversed by the addition of TGF beta1. Tumors that did arise from the K6 antisense transfectant cells had lost antisense TGF beta1 expression and expressed the same TGF beta1 mRNA levels as controls. U9A cells were more metastatic to the liver after intrasplenic injection than K6 cells. These findings demonstrate a role for autocrine TGE beta1 in colon cancer tumorigenicity and invasion. They also show that a relatively small decrease in TGF beta1 levels was enough to markedly decrease colon carcinoma cell aggressiveness. This is not unprecedented, as we had found in an earlier study that a small, 2-4-fold increase in TGF beta1 protein levels in human colon cancers correlated with disease progression to metastases (E. Friedman et al., Cancer Epidemiol, Biomarkers & Prev., 4:549-554, 1995).
 ...
PMID:Transforming growth factor beta 1 (TGF beta 1) is an autocrine positive regulator of colon carcinoma U9 cells in vivo as shown by transfection of a TGF beta 1 antisense expression plasmid. 901 69

Destruction of the basement membrane (BM) is mandatory for tumor spread, and matrix metalloproteinases (MMPs) are known to be implicated in colon cancer invasion and metastasis by digesting type IV collagen, a main component of the BM. The current study analyzed the expression of MMP-2 and MMP-9 in pancreatic cancer tissues. Frozen specimens of pancreatic cancer (n = 10), a liver metastatic nodule from pancreatic cancer (n = 1), and normal pancreas (n = 3) were homogenized and analyzed by zymography. The activated form of MMP-9 (82 kDa) was detected in all of the normal and malignant tissues, while the activated form of MMP-2 (62 kDa) was detected in all of the pancreatic cancers and its metastatic tissue, but not in the normal pancreatic tissues. These results indicate that expression of the activated form of MMP-2 may be specific to pancreatic cancer, while that of MMP-9 may be unrelated to it.
 ...
PMID:Detection of matrix metalloproteinase activity in human pancreatic cancer. 908 44

Previously, we have reported on successful imaging of colon, rectal, and pancreatic carcinomas in patients by using a radiolabeled all-human monoclonal antibody, COU-1, directed against modified cytokeratin. To further develop this antibody for use as an immunoconjugate, COU-1 was cloned by phage display selection and the human Fab fragment was expressed in bacteria. Analysis by confocal laser scanning microscopy demonstrated that COU-1 bound in a uniform punctate pattern to the surface of viable carcinoma cells stained at 4 degrees C, and binding increased significantly when cells were cultured on fibronectin, laminin, or collagen IV. In the case of fibronectin, COU-1 staining was particularly enhanced at intercellular junctions. When carcinoma cells were cultured with COU-1 at 37 degrees C for 6 hr, the antibody was found in large perinuclear vesicles and the punctate surface staining was significantly reduced. Similar results were obtained using intact IgM COU-1 and the recombinant Fab fragment. Immunohistological studies indicated that COU-1, in contrast to murine monoclonal antibodies against normal cytokeratin 8 and 18, could differentiate between malignant and normal colon epithelia, and between colon cancer metastasis in the liver and surrounding normal hepatocytes. Within biopsies of malignant tissue, COU-1 exhibited membrane-associated staining of proliferating cells, while resting cells had a filamentous pattern. Thus, modified cytokeratin at the surface of carcinoma cells may represent a new target for immunoconjugates and may explain the promising results of the phase I/II clinical study.
 ...
PMID:Modified cytokeratins expressed on the surface of carcinoma cells undergo endocytosis upon binding of human monoclonal antibody and its recombinant Fab fragment. 922 23

Colon carcinomas commonly contain mutations in Ki-ras4B, but very rarely in Ha-ras, suggesting that different Ras isoforms may have distinct functions in colon epithelial cell biology. In an earlier study we had demonstrated that oncogenic Ki-ras4BVal-12, but not oncogenic Ha-rasVal-12, blocks the apicobasal polarization of colon epithelial cells by preventing normal glycosylation of the integrin beta1 chain of the collagen receptor. As a result, only the Ki-ras mutated cells exhibited altered cell to substratum attachment, whereas mutation of either Ras isoform activated mitogen-activated protein kinases. We have now asked whether intercellular adhesion proteins implicated in establishing basolateral polarity in colon epithelial cells are modulated by oncogenic Ki-Ras4BVal-12 proteins but not oncogenic Ha-RasVal-12 proteins. The embryonic adhesion protein carcinoembryonic antigen (CEA) was up-regulated on the mRNA and protein levels in each of three stable Ki-rasVal-12 transfectant lines but in none of three stable Ha-rasVal-12 transfectant lines. The elevated protein levels of CEA in Ki-ras4BVal-12 transfectant cells were decreased by blocking expression of Ki-ras4BVal-12 with antisense oligonucleotides. N-cadherin levels were decreased in only the Ki-ras transfectants, whereas E-cadherin levels were unchanged. Immunohistochemical analysis demonstrated that Ki-ras4BVal-12 transfectant cells did not polarize into cells with discrete apical and basal regions and so could not restrict expression of CEA to the apical region. These unpolarized cells displayed elevated levels of CEA all along their surface membrane where CEA mediated random, multilayered associations of tumor cells. This aggregation was both calcium-independent and blocked by Fab' fragments of anti-CEA monoclonal antibody col-1. Trafficking of the lysosomal cysteine protease cathepsin B may also be altered when cell polarity cannot be established. Ki-ras4BVal-12 transfectant cells expressed 2-fold elevated protein levels of the lysosomal cysteine protease cathepsin B but did not up-regulate cathepsin B mRNA expression. One function of oncogenic c-Ki-Ras proteins in colon cancer progression may be to up-regulate CEA and thus to prevent the lateral adhesion of adjacent colon epithelial cells that normally form a monolayer in vivo.
 ...
PMID:Oncogenic c-Ki-ras but not oncogenic c-Ha-ras up-regulates CEA expression and disrupts basolateral polarity in colon epithelial cells. 934 38


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>