The influence of TNF-alpha on concentration of soluble adhesion molecules in cultures of HT-29 cells exposed to inositol hexaphosphate.

The latest studies suggest that adhesion molecules are involved in the arising of malignant changes and in distant metastasis induction. The soluble forms of several adhesion molecules, have recently emerged as novel and potentially useful tumor markers. Among a number of identified, high interest wake soluble molecules similar to the immunoglobulin -- soluble intercellular adhesion molecules-1 (sICAM-1) and soluble E-cadherin (sE-cadherin). In the present work, the authors concentrate on one tumor type, colorectal carcinoma, in which distant metastases, are the main cause of failure, in spite of surgical curing of the primary tumor. It is known that TNF-alpha (tumor necrosis factor - alpha) serum concentration of patients with cancer is raised. The changes in soluble adhesion molecules concentrations in serum and others fluids, could be modulated by many different factors affecting cancer cells. In the case of colon cancer one of the factors is a high-fiber diet, containing an anti-cancer chemical, inositol hexaphosphate (IP6). The aim of this study was to estimate the influence of TNF-alpha on the concentration of sICAM-1 and sE-cadherin in the microenvironment of HT-29 malignant epithelial colorectal cells stimulated with IP6. Additonally, adhesive property of HT-29 human colorectal cancer cell line to collagen I was estimated. The HT-29 cells were treated with TNF-alpha (10 ng/mL and 100 ng/mL - estimation of sICAM and sE-cadherin concentration; 100 ng/mL - adhesion assay), IP6 (0.5 mM, 1.0 mM, 2.0 mM) and TNF-alpha in combination with IP6. The level of sICAM-1 and sE-cadherin in cultures of HT-29 cells was measured by enzyme-linked immunosorbent assay (R&D Systems), and adhesion of the cells to collagen I was investigated by Cyquant Proliferation Assay Kit. The present findings demonstrate that TNF-alpha and inositol hexaphosphate have an effect on the sICAM-1 and sE-cadherin concentration in cultures of HT-29 cells. IP6 at a concentration of 2.0 mM induced a decrease of sE-cadherin concentration in cultures of these cells and significantly reduced their adhesion to collagen I. TNF-alpha at concentration of 100 ng/mL caused the significant increase in the sICAM-1 level, but to a lesser degree in the presence of higher concentrations of IP6. However, TNF-alpha did not cause such a significant increase in sE-cadherin level. The sE-cadherin concentration was most likely associated with inositol hexaphosphate activity.

Impact of celecoxib on soluble intercellular adhesion molecule-1 and soluble e-cadherin concentrations in human colon cancer cell line cultures exposed to phytic acid and TNF-alpha.

Soluble adhesion molecules such as soluble intercellular adhesion molecules-1 (sICAM-1) and soluble E-cadherin (sE-cadherin) play important role in tumor invasion and the development of metastasis. It was observed that their concentrations in body fluids of patients with colon cancer were elevated. Celecoxib, a selective inhibitor of cyclooxygenase-2 (COX-2) besides its analgesic, anti-inflammatory, and antipyretic activity is able to inhibit development of colon cancer and reduce risk of metastasis. The additional factors, e.g., dietary components in colon cancer, may influence therapeutic effect of drugs, such as cytokines. TNF-alpha (tumor necrosis factor - alpha) is a cytokine, which concentration significantly increases in serum of patients with inflammatory and cancer diseases. The latest studies demonstrate, that phytic acid (IP6), a myo-inositol derivative, abundantly present in high-fiber diets could substantially reduce colon cancer incidence. The aim of the present study was to evaluate the influence of celecoxib on sICAM-1 and sE-cadherin concentrations in transformed epithelial colon cell cultures simultaneously exposed to IP6 and TNF-alpha. Additionally, the adhesion of the exposed cells to collagen I was assessed. HT-29 and Caco-2 cells were cultured in the presence of 50 ng/mL celecoxib, 1.0 mM IP6, and 100 ng/mL TNF-alpha, and their combination: TNF-alpha plus IP6, TNF-alpha plus celecoxib, IP6 plus celecoxib, and TNF-alpha with celecoxib plus IP6, for 96 h. Nonexposed cell line cultures served as controls. Concentrations of sICAM-1 and sE-cadherin were measured in the culture medium by enzyme-linked immunosorbent assay (ELISA) using Quantikine - Human sICAM-1/CD54 Immunoassay and Quantikine-Human sE-Cadherin Immunoassay. All the results obtained were expressed as ng per mL. In the adhesion assay, the cells were incubated with IP6 (0.5, 1.0 and 2.0 mM), TNF-alpha (100 ng/mL), celecoxib (50 ng/mL) and their combination for 90 min. Fluorescence values 480 nm/530 nm reflected concentrations of DNA in cells attached to collagen I. The obtained results indicate that celecoxib (50 ng/mL), the selective COX-2 inhibitor, reduces significantly sICAM-1 and sE-cadherin concentrations in HT-29 and Caco-2 transformed human epithelial colorectal cell line cultures co-treated with IP6 (1.0 mM) and TNF-alpha (100 ng/mL). A decrease of cells adhesion property to collagen I was observed under the influence of 50 ng/mL celecoxib on cell cultures exposed to 1.0 or 2.0 mM IP6 and 1.0 or 2.0 mM IP6 plus 100 ng/mL TNF-alpha.

The influence of phytic acid on TNF-alpha and its receptors genes' expression in colon cancer Caco-2 cells.

Inositol hexaphosphate (IP6, phytic acid) is a naturally occurring carbohydrate abundantly present in high-fiber diets and it is also contained in almost all mammalian cells. It plays an important role in signal transduction, cell proliferation and differentiation. Some natural substances have been shown to elicit an impact on the expression of TNF-alpha and its receptors in cancer cells. TNF-alpha represents cytokine very often deregulated at the level of both gene expression and signal transmission through TNF-alpha receptors (TNFRI and TNFRII). The aim of the present study was to analyze the IP6 influence on the transcription of genes coding for TNF-alpha and its receptors in human colon cancer cells line Caco-2 Real-time QRT-PCR based on TaqMan methodology was applied to analyze quantitatively the transcript levels of these genes. Three concentrations (1, 2.5 and 5 mM) of IP6 were used for Caco-2 cells stimulation for 1, 6, 12 and 24 h. The results showed that IP6 modulated the expression of the listed genes at transcription level in a dose and time dependent manner. The enhanced TNFRI and decreased TNF-alpha and TNFRII transcription in Caco-2 cells stimulated for 12 h with IP6 seems to be the presumptive evidence for anti-inflammatory and antitumor activity of IP6.

Evaluation of the expression of transcriptional factor NF-kappaB induced by phytic acid in colon cancer cells.

Over the last years phytic acid, a hexaphosphorylated inositol (IP6) has attracted particular attention due to its anti-cancer activity, however, the molecular mechanisms of its action have not been elucidated, as yet. The aim of this study was to evaluate the influence of phytic acid on the expression of genes encoding p65 and p50 subunits of NF-kappaB and of its inhibitor IkappaBalpha in human colorectal cancer cell line Caco-2. A kinetic study of p65 and p50 subunits and IkappaBalpha mRNAs expression was performed on Caco-2 cells after treatment with 1, 2.5 and 5 mM IP6 for 1, 6, 12 and 24 h. Quantification of the genes expression was carried out using real time QRT-PCR technique. Treatment of cells with 5 mM IP6 resulted in a strong increase in IkappaBalpha expression at 6 h, 12 h and 24 h. The level of p65 transcript after 1 h was lower in the cells exposed to 1, 2.5, and 5 mM IP6 than in the control cells. The increase in transcriptional activity of p65 gene in response to 5 mM IP6 after 6 h and 12 h was observed. Cells treated for 24 h with 2.5 mM and 5 mM IP6 showed a significant decrease in expression of p65 gene. There were no quantitative changes in the p50 gene expression in the cells treated with IP6 compared to the control cells. High positive correlation between the expression of IkappaBalpha and p65 was detected. The results of this study suggest that IP6 primarily influences p65 and IkappaBalpha genes expression in colon cancer cells. Changes in transcriptional activities of IkappaBalpha and p65 depend on IP6 concentration and time of its action.

Quantitative analysis of the level of p53 and p21(WAF1) mRNA in human colon cancer HT-29 cells treated with inositol hexaphosphate.

The aim of this study was to analyze the molecular mechanism of inositol hexaphosphate (InsP(6)) action through which it may inhibit proliferation of colon cancer cells and cell cycle progression. A kinetic study of p53 and p21(WAF1) mRNA increase was performed on human colon cancer HT-29 cells after treatment with 1, 5 and 10 mM InsP(6) for 6, 12, 24 and 48 h. Real-time-QPCR based on TaqMan methodology was applied to analyze quantitatively the transcript levels of these genes. The transcription of beta-actin and GAPDH genes was assessed in parallel to select the control gene with least variability. The 2(-Delta Delta Ct) method was used to analyze the relative changes in gene transcription. InsP(6) stimulated p53 and p21(WAF1) expression at the mRNA level, with the highest increase in p21(WAF1) mRNA occurring at 24 h, i.e., following the highest increase in p53 mRNA observed at 12 h. Based on these studies it may be concluded that the ability of InsP(6) to arrest the cell cycle may be mediated by the transcriptional up-regulation of the p53-responsive p21(WAF1) gene.

Butyrate-induced differentiation of colon cancer cells is PKC and JNK dependent.

Butyric acid, a short-chain fatty acid physiologically present in human large gut, is derived from bacterial fermentation of complex carbohydrates. It has been shown to reduce the growth and motility of colon cancer cell lines and to induce cell differentiation and apoptosis. Apoptosis is considered a result of normal colonocyte terminal differentiation in vivo. The aim of this study was to characterize the cellular mechanisms regulating differentiation of colon cancer cells stimulated with sodium butyrate (NaB). The two human colon cancer cell lines Caco-2 and HT-29 were treated with NaB at physiologically relevant concentrations. Alkaline phosphatase (ALP) activity, a marker of colonocyte differentiation, was increased 48 hr after treatment with 1 mM NaB. Higher doses of NaB (5 and 10 mM) induced apoptosis of the cells and failed to stimulate the colonocyte differentiation. Therefore, we assumed that butyrate augments cell differentiation and induces apoptosis, acting via various intracellular mechanisms, and butyrate-mediated programmed cell death cannot be considered a consequence of colonocyte terminal differentiation. The effect of NaB on ALP activity was significantly attenuated in the presence of inhibitors of protein kinase C and JNK. Inhibition of MEK-ERK signal transduction pathways augmented the impact of butyrate on colonocyte differentiation. These results suggest that butyrate could influence the colonocyte differentiation via modulation of the activity of cellular protein kinases and signal transduction.

Evaluation of biotransformation of sulphasalazine in the colon epithelial Caco-2 cells.

Sulphasalazine (salicyl-azo-sulphapiridine, SAS) is a drug commonly used in the treatment of non-specific inflammatory bowel diseases, such as ulcerative colitis and Crohn disease. Chronic inflammatory states of the colon can lead to neoplastic changes of the intestinal mucosa. There are some suggestions in the literature that the intestinal bacterial azo-reductases are involved in biotransformation of SAS into 5-aminosalicylic acid (5-ASA) and sulphapyridine (SP). For this reason, it seemed worth of investigating whether transformation of SAS could be performed by the colon epithelial cells themselves. No enzymatic systems presumably exist in Caco-2, which could be responsible for SAS metabolism, because after 72 h-incubation of cell cultures with 1 mM SAS, its metabolites i.e., 5-ASA and SP were not detected in cells, neither in culture media. SAS metabolism, therefore, seems to depend on the presence of intestinal bacterial enzymatic systems. It was confirmed that 5-ASA is converted by Caco-2 cells to N-acetyl-5-aminosalicylic acid (Ac-5-ASA), which migrates to the culture medium. The other metabolite of SAS i.e., SP, was not transformed in the human colon cancer cells at all.

Application of HPLC for determination of phytic acid in the colonic epithelial Caco-2 cells.

Phytic acid (myo-inositol hexaphosphate, IP6) is currently receiving a considerable interest because of its anticancer (preventive and therapeutic) potential against colon tumors and the need for methods of its determination. The aim of this study was to analyze the uptake of IP6 by human colon adenocarcinoma cells (Caco-2 cell line) and to evaluate the method of its intracellular quantification with the use of high performance liquid chromatography (HPLC) technique. Chromatographic analysis revealed a rapid uptake of IP6 by cells. The intracellular accumulation of IP6 was saturable at 0.5 h and it did not change with the prolongation of incubation up to 72 h.

Desulfovibrio desulfuricans lipopolysaccharides induce endothelial cell IL-6 and IL-8 secretion and E-selectin and VCAM-1 expression.

The aim of this study was to determine whether Desulfovibrio desulfuricans-derived LPS stimulate the release of IL-6 and IL-8 from ECs and the expression of their adhesion molecules at the transcriptional level. Confluent monolayers of HUVEC were incubated in the absence or presence of 20 microg/ml and 60 microg/ml LPSs derived from the DdT and DdA bacterial strains. Also, the simultaneous stimulation of cells with LPSs and IL-1beta was evaluated. The levels of cytokines released were measured using ELISA. LPS-activated HUVEC increased the secretion of both IL-6 and IL-8, which was not LPS dose dependent. The expression of E-selectin and VCAM-1 was assessed by TR-PCR. The transcripts were detectable at all the concentrations (20, 40, 60 microg/ml) of LPSs used. These results suggest that D. desulfuricans LPS may activate immune functions in endothelial cells and influence the inflammatory response during bacteremia caused by these bacteria.

The effect of sulphasalazine and its metabolites on the colonic epithelial Caco-2 cells.

Sulphaselazine (SAS) is a drug commonly used to treat patients suffering from chronic inflammatory states such as inflammatory bowel diseases. It was shown that besides bacteriostatic, antiinflammatory and immunosuppressive activity of this drug, the risk of neoplastic changes in the colon and rectum was substantially diminished during ulcerative colitis therapy with SAS. In the present study the effects of SAS and its main metabolites--sulphapyridine (SP) and 5-aminosalicylic acid (5-ASA) on colon adenocarcinoma Caco-2 cells viability and proliferation was evaluated. Significant inhibitory impact of SAS was observed already at 1 mM concentration whereas 5-ASA and SP impaired cellular growth when used at 5 mM concentration. 5 mM SAS exerted a strong cytotoxic effect on Caco-2 cells resulting in their necrotic death. The inhibition of cellular proliferation and the cytotoxic effects of SAS and its metabolites (5-ASA and SP) on the colonic carcinoma cells (Caco-2) confirm the suggestions that these compounds at appropriate concentrations may reduce the risk of neoplastic changes frequently initiated by prolonged inflammatory states.