Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: UMLS:C0699790 (colon cancer)
28,837 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Monoclonal antibody CC83 is a second-generation high-affinity antibody directed against the TAG-72 antigen in colorectal cancer. Our objectives were to evaluate the biodistribution, pharmacokinetics and imaging properties of CC83 labelled with 99Tcm via a modified Schwartz technique. The immunological integrity of 99Tcm-CC83 was evaluated by size-exclusion FPLC and by determining the immunoreactive fraction in vitro against bovine submaxillary mucin. The biodistribution of 99Tcm-CC83 up to 24 h postinjection was evaluated in nude mice bearing subcutaneous LS174T human colon cancer xenografts. Blood radioactivity data was fitted to a one-compartment pharmacokinetic model. Images of tumour-bearing mice were obtained at 17-24 h postinjection with 99Tcm-CC83. 99Tcm-CC83 was eluted as intact immunoglobulin by FPLC analysis and the mean immunoreactive fraction was 0.49 +/- 0.15. Tumour uptake at 24 h postinjection was 11.2 +/- 4.1% i.d.g-1. Radioactivity in the blood was eliminated rapidly with a half-life of 8 h and tumour:blood ratios were > 2:1 at 24 h postinjection. LS174T tumours were successfully imaged in 3/3 mice. In vitro studies showed instability of 99Tcm-CC83 when challenged with cysteine and glutathione but not metallothionein, suggesting a metabolic route for the 99Tcm antibody in vivo. We conclude that CC83 labelled directly with 99Tcm retains its immunological integrity and capability specifically to target subcutaneous LS174T human colon cancer tumours hosted in nude mice. These results further suggest that 99Tcm-CC83 may have potential for imaging colorectal cancer in humans.
...
PMID:Immunoscintigraphy of human colon cancer xenografts in nude mice using a second-generation TAG-72 monoclonal antibody labelled with 99Tcm. 804 23

Transforming growth factor alpha (TGF alpha) is a growth factor produced by colon cancer cells which may function as an autocrine growth regulator. Therefore, the proliferation and transformation of colon cancer cells might be attenuated by blocking the production of endogenous TGF alpha. GEO cells, from a human colon carcinoma cell line that expresses TGF alpha and functional epidermal growth factor (EGF) receptors, were infected with a replication-defective, recombinant amphotropic retroviral expression vector containing the neomycin-resistance gene and a 435-bp ApaI-EcoRI coding fragment of the human TGF alpha cDNA oriented in the 3' to 5' direction under the transcriptional control of the heavy-metal-inducible mouse metallothionein I promoter. Following antibiotic selection, G418-resistant colonies were pooled and expanded into a cell line (GEO TGF alpha AS cells). A 50 to 70% inhibition in the production of secreted and cell-associated TGF alpha protein was observed in GEO TGF alpha AS cells that had been maintained in CdCl2-supplemented medium. Moreover, a growth inhibition of 70% and 50% was observed in CdCl2-treated GEO TGF alpha AS cells under anchorage-dependent and anchorage-independent culture conditions, respectively. In contrast, CdCl2 treatment of parental GEO cells had no significant effect upon these parameters. Our results suggest that TGF alpha may be involved in modulating the in vitro cell growth and transformation of human colon cancer cells that express both this growth factor and its cognate receptor.
...
PMID:Infection with a transforming growth factor alpha anti-sense retroviral expression vector reduces the in vitro growth and transformation of a human colon cancer cell line. 833 3

Human colon cancer cells utilize the epidermal growth factor (EGF) family of growth factors and the receptor for these growth factors (EGFR) in sustaining their malignant phenotype. Disrupting EGFR expression by expressing antisense EGFR RNA (through transfection with an appropriate antisense EGFR expression vector under metallothionein promoter control) downregulated the malignant behavior of human colon cancer Moser cells and blocked the ability of exogenous EGF in stimulating malignant cell behavior. The antiproliferative effect of antisense EGFR expression vector was determined in three human colon cancer cell lines (Moser, HCT116 and HT29 possessing different biological properties and rate of proliferation) in an in vitro therapeutic setting using an antisense EGFR expression vector under the control of a viral promoter. Different degree of inhibition was achieved for each cell line after one dose of antisense treatment. The differences in the antiproliferative effect observed may be due to differences in the rate of proliferation and/or recovery from antisense effect, and the differences in transfection efficiency among the cell lines.
...
PMID:Inhibition of human colon cancer malignant cell behavior and growth by antisense epidermal growth factor receptor expression vector. 970 69

Insulin-like growth factor-1 (IGF-1) is expressed in many tumor cell lines and has a role in both normal cell proliferation and in the growth of cancers. Tumor cells transfected with a vector encoding an IGF-1 antisense cDNA transcriptional cassette driven by the mouse metallothionein-1 promoter become immunogenic and lose their tumorigenicity in syngeneic animals. The enhanced immunogenicity is associated with an up-regulation in the expression of major histocompatibility complex class I molecule on cell surfaces. Blockade of the expression of IGF-1 in tumor cells by the IGF-1 antisense RNA approach is not uniformly effective in the induction of antitumoral protective immunity in low and nonimmunogenic tumor model systems. Here, we report that the immunogenicity of hepa 1-6 hepatoma and SMCC-1 colon carcinoma cells, which are poorly immunogenic and unresponsive to antisense IGF-1 gene transfer, can be induced by cotransfection with genes encoding antisense IGF-1 and mouse B7.1 molecules. The tumor cells modified in this manner become strongly immunogenic and can be used as a cellular vaccine to induce a protective immune response in vivo. Immunization with the transfected tumor cells also results in regression of the established hepa 1-6 hepatoma and SMCC-1 colon cancer. The immunity is tumor-specific and is mediated by CD3+ CD8+ T cells. Cytotoxic T lymphocytes generated in vitro by priming naive spleen cells and in vivo by immunizing mice with the double-transfected tumor cells specifically lysed autologous tumors cells and were effective in adoptive immunotherapy. The data suggest that modification of tumor cells in vitro by cotransfection with genes encoding antisense IGF-1 and B7.1 molecules may open a new avenue for cancer immunogene therapy.
...
PMID:Enhancement of immunogenicity of tumor cells by cotransfection with genes encoding antisense insulin-like growth factor-1 and B7.1 molecules. 1076 52

BACKGROUND: Curcumin is a spice and a coloring food compound with a promising role in colon cancer prevention. Curcumin protects against development of colon tumors in rats treated with a colon carcinogen, in colon cancer cells curcumin can inhibit cell proliferation and induce apoptosis, it is an anti-oxidant and it can act as an anti-inflammatory agent. The aim of this study was to elucidate mechanisms and effect of curcumin in colon cancer cells using gene expression profiling. METHODS: Gene expression changes in response to curcumin exposure were studied in two human colon cancer cell lines, using cDNA microarrays with four thousand human genes. HT29 cells were exposed to two different concentrations of curcumin and gene expression changes were followed in time (3, 6, 12, 24 and 48 hours). Gene expression changes after short-term exposure (3 or 6 hours) to curcumin were also studied in a second cell type, Caco-2 cells. RESULTS: Gene expression changes (>1.5-fold) were found at all time points. HT29 cells were more sensitive to curcumin than Caco-2 cells. Early response genes were involved in cell cycle, signal transduction, DNA repair, gene transcription, cell adhesion and xenobiotic metabolism. In HT29 cells curcumin modulated a number of cell cycle genes of which several have a role in transition through the G2/M phase. This corresponded to a cell cycle arrest in the G2/M phase as was observed by flow cytometry. Functional groups with a similar expression profile included genes involved in phase-II metabolism that were induced by curcumin after 12 and 24 hours. Expression of some cytochrome P450 genes was downregulated by curcumin in HT29 and Caco-2 cells. In addition, curcumin affected expression of metallothionein genes, tubulin genes, p53 and other genes involved in colon carcinogenesis. CONCLUSIONS: This study has extended knowledge on pathways or processes already reported to be affected by curcumin (cell cycle arrest, phase-II genes). Moreover, potential new leads to genes and pathways that could play a role in colon cancer prevention by curcumin were identified.
...
PMID:Time- and dose-dependent effects of curcumin on gene expression in human colon cancer cells. 1514 Feb 56

Genetic instability plays a central role in the development and progression of human cancer. Two major classes of genetic instability, microsatellite instability (MSI) and chromosome instability (microsatellite stable; MSS), are best understood in the context of colon cancer, where MSI tumors represent approximately 15% of cases, and compared with MSS tumors, more often arise in the proximal colon and display favorable clinical outcome. To further explore molecular differences, we profiled gene expression in a set of 18 colon cancer cell lines using cDNA microarrays representing approximately 21,000 different genes. Supervised analysis identified a robust expression signature distinguishing MSI and MSS samples. As few as eight genes predicted with high accuracy the underlying genetic instability in the original and in three independent sample sets, comprising 13 colon cancer cell lines, 61 colorectal tumors, and 87 gastric tumors. Notably, the MSI signature was retained despite genetically correcting the underlying instability, suggesting the signature reflects a legacy of the tumor having arisen from MSI, rather than sensing the ongoing state of MSI. Our findings support a model in which MSI and MSS preferentially target different genes and pathways in cancer. Further, among the MSI signature genes, our findings implicate a role of elevated metallothionein expression in the clinical behavior of MSI cancers.
...
PMID:A gene expression signature of genetic instability in colon cancer. 1623 Mar 80

In spite of the paramount importance of zinc in biology, dynamic aspects of cellular zinc metabolism remain poorly defined at the molecular level. Investigations with human colon cancer (HT-29) cells establish a total cellular zinc concentration of 264 microM. Remarkably, about 10% of the potential high-affinity zinc-binding sites are not occupied by zinc, resulting in a surplus of 28 muM ligands (average Kd(c) = 83 pM) that ascertain cellular zinc-buffering capacity and maintain the "free" zinc concentration in proliferating cells at picomolar levels (784 pM, pZn = 9.1). This zinc-buffering capacity allows zinc to fluctuate only with relatively small amplitudes (DeltapZn = 0.3; below 1 nM) without significantly perturbing physiological pZn. Thus, the "free" zinc concentrations in resting and differentiated HT-29 cells are 614 pM and 1.25 nM, respectively. The calculation of these "free" zinc concentrations is based on measurements at different concentrations of the fluorogenic zinc-chelating agent and extrapolation to a zero concentration of the agent. It depends on the state of the cell, its buffering capacity, and the zinc dissociation constant of the chelating agent. Zinc induction of thionein (apometallothionein) ensures a surplus of unbound ligands, increases zinc-buffering capacity and the availability of zinc (DeltapZn = 0.8), but preserves the zinc-buffering capacity of the unoccupied high-affinity zinc-binding sites, perhaps for crucial physiological functions. Jointly, metallothionein and thionein function as the major zinc buffer under conditions of increased cellular zinc.
...
PMID:Zinc-buffering capacity of a eukaryotic cell at physiological pZn. 1692 57

This research assessed the importance of the adenomatous polyposis coli (APC) tumor suppressor mutation in the ability of apigenin to induce cell cycle arrest using HT29-APC cells, which contain inducible wild-type APC under the metallothionein promoter. HT29-GAL cells, containing beta-galactosidase (GAL), were included as control. Treatment with apigenin (0, 20, 40, 60, and 80 microM) for 48 h resulted in reduction in the cell number (P < 0.05) concurrent with flow cytometry results showing a dose-dependent accumulation of cells in the G2/M phase in both HT29-APC and HT29-GAL cells without ZnCl(2) treatment. Flow cytometric analysis showed an increase (P < 0.05) in the percentage of cells in G2/M when HT29-APC cells were treated with 80 microM apigenin for 120 h. This increase was not present in HT29-APC cells when treated with both 80 microM apigenin and 100 microM ZnCl(2) for 120 h. Western blot analysis verified the induction of APC protein expression in ZnCl(2)-treated HT29-APC cells but not in ZnCl(2)-treated HT29-GAL cells. Apigenin plus ZnCl(2) treatment increased the expression of APC protein in HT29-APC cells by 50 fold above expression observed with ZnCl(2) alone. Upon induction of the APC gene with ZnCl(2) in HT29-APC cells, the percentage of apoptotic cells increased significantly (P < 0.05) after 120-h treatment. Additionally, apigenin treatment (80 microM) further increased the percentage of apopototic HT29-APC following ZnCl(2) treatment to induce wild-type APC expression. These results suggest that APC dysfunction may be critical for apigenin to induce cell cycle arrest in human colon cancer cell lines and furthermore, apigenin enhances APC expression and apoptosis in cells with wild-type APC.
...
PMID:Impact of adenomatous polyposis coli (APC) tumor supressor gene in human colon cancer cell lines on cell cycle arrest by apigenin. 1762 Feb 92

Src kinase has been linked as a causative agent in the progression of a number of cancers including colon, breast, lung and melanoma. Src protein and activity levels are increased in colorectal cancer and liver metastases arising secondary to colon cancer. However, although Src protein is increased in colon cancer as early as the adenomatous polyp stage, a role for Src in carcinogenesis has not been established. We developed the c-SRC transgenic mouse in the C57BL/6 strain to address the issue of carcinogenesis in cells with high levels of Src expression. The transgene was constructed with the human c-SRC gene downstream of the mouse metallothionein promoter to create zinc inducible gene expression. In these C57BL/6 mice, Src protein was increased in a number of tissues both with and without zinc induction. No additional carcinogenic agent was administered. After 20 months, mice were assessed for tumor development in the liver and GI tract, as well as other organs. Of the mice with the transgene, 15% developed tumors in the liver while no tumors were detected in wild type C57BL/6 mice. A further study was conducted by crossing c-SRC C57BL/6 mice with p21 nullizygous mice to determine the effect of oncogene expression combined with inactivation of the tumor suppressor gene, p21. Addition of the c-SRC transgene to the p21-/- background increased tumor formation almost 3-fold, while it increased metastasis 6-fold. The data from our study show, for the first time, that Src kinase may play a role in carcinogenesis.
...
PMID:Src kinase induces tumor formation in the c-SRC C57BL/6 mouse. 1835 44

5-Azactydine inhibits cell growth by direct cytotoxic action as well as by inhibition of DNA methyl transferase enzyme. Inhibitors of DNMT have been reported to potentiate the therapeutic activity of cisplatin in vitro. Dose dependent bone marrow toxicity, neurotoxicity and nephrotoxicity are the major side effects of cisplatin, limiting its use as an effective chemotherapeutic agent. The present study was aimed to reduce the nephrotoxic potential of cisplatin without compensating its potency. To best of our knowledge, this is the first report which shows that the combination of 5-azacytidine with cisplatin leads to remarkable reduction in nephrotoxicity, by involving inhibition of cisplatin induced metallothionein expression. 5-Azacytidine treatment with cisplatin leads to maximum reduction in tumor size in DMH induced colon cancer and tumor volume in DMBA induced breast cancer bearing SD rats. This combination regimen prevents phosphorylation and acetylation of histone H3 which may be involved in inhibition of aberrant gene expression in colon tumors. Further, 5-azacytidine potentiated cisplatin induced antitumor activity by involving decreased expression of pAKT, DNMT1 and an increased expression of p38 in colon tumors. Thus, combination of 5-azactydine with cisplatin attenuates the cisplatin induced nephrotoxicity and potentiates the anti-cancer activity which can have profound clinical implications.
...
PMID:5-Azacytidine prevents cisplatin induced nephrotoxicity and potentiates anticancer activity of cisplatin by involving inhibition of metallothionein, pAKT and DNMT1 expression in chemical induced cancer rats. 1972 70


1 2 Next >>

---