Effect of indomethacin on E-cadherin and beta-catenin expression in HT-29 colon cancer cells.
ABSTRACT Nonsteroidal anti-inflammatory drugs (NSAIDs) lower the incidence of and mortality from colon cancer. Although there is much evidence from epidemiological and laboratory studies that NSAIDs have antitumor activity and reduce the incidence of colon cancer, the mechanism of action remains unknown. In this paper, we present the effect of indomethacin on growth inhibition, induction of apoptosis, and alterations in the expression of several genes involved in Wnt signaling in HT-29 colon cancer cells. We have shown that indomethacin reduces the proliferation rate of HT-29 colon cancer cells and induces apoptosis. Concentrations of indomethacin from 10(-4) to 10(-3) M strongly inhibited the growth of HT-29 cells. The inhibition of growth, as well as induction of apoptosis was dose and time dependent. The treatment of cells with 4 x 10(-4) M indomethacin caused strong inhibition of cell growth (about 70%), enhanced expression of APC, decreased expression of beta-catenin and induced expression of E-cadherin proteins. Expression of beta-catenin was not markedly reduced instead, beta-catenin was translocated from the nucleus and cytoplasm to the plasma membrane. These results were confirmed by real-time RT-PCR analysis on mRNA level. At a concentration of 4 x 10(-4) M indomethacin there was increased expression of APC gene (10.9-fold induction; DeltaDeltaCt = 3.43) and E-cadherin gene (3.5-fold induction; DeltaDeltaCt = 1.79). These results suggest the antiproliferative effect of indomethacin may contribute to enhanced cell adhesion through increased expression of E-cadherin and translocation of beta-catenin from the nucleus to the cell membrane.
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ABSTRACT: The objective of this study was to investigate a novel hydrogel plug using isolated root mucilage of Sterculia urens to obtain a desired lag time for an oral chronotherapeutic colon-specific pulsatile drug delivery of indomethacin. Pulsatile drug delivery was developed using chemically treated hard gelatin capsule bodies filled with eudragit multiparticulates of indomethacin, and sealed with different hydrogel plugs (root mucilage of S. urens, xanthan gum, guar gum, HPMC K4M and combination of maltodextrin with guar gum). Indomethacin multiparticulates were prepared using extrusion spheronization, spray drying and solvent evaporation techniques with Eudragit® L-100 and S-100 (1:2) by varying drug-to-polymer ratio. After oral administration, the water-soluble cap of capsule dissolved in the intestinal fluid and the hydrogel plug swells. After a controlled time, the swollen plug subsequently ejected from the dosage form, releases the contents of the capsule. The formulation factors affecting the drug release were concentration and types of hydrogel plug used. In vivo gamma scintigraphy study in healthy rabbits proved the capability of the system to release drug in lower parts of the gastrointestinal tract after a programmed lag time. This study demonstrates that the indomethacin multiparticulates could be successfully colon-targeted by the design of time and pH-dependent modified chronopharmaceutical formulation. In conclusion, the investigated novel hydrogel plug could be a valuable tool for achieving desired lag time.Journal of Microencapsulation 01/2012; 29(1):72-82. · 1.57 Impact Factor
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ABSTRACT: Nitric oxide-donating aspirin (NO-ASA) is a promising agent for cancer prevention. Although studied extensively, its molecular targets and mechanism of action are still unclear. S-nitrosylation of signaling proteins is emerging as an important regulatory mechanism by NO. Here, we examined whether S-nitrosylation of the NF-κB, p53, and Wnt signaling proteins by NO-ASA might explain, in part, its mechanism of action in colon cancer. NO-ASA releases significant amounts of NO detected intracellularly in HCT116 and HT-29 colon cells. Using a modified biotin switch assay we demonstrated that NO-ASA S-nitrosylates the signaling proteins p53, β-catenin, and NF-κB, in colon cancer cells in a time- and concentration-dependent manner. NO-ASA suppresses NF-κB binding to its cognate DNA oligonucleotide, which occurs without changes in the nuclear levels of the NF-κB subunits p65 and p50 and is reversed by dithiothreitol that reduces -S-NO to -SH. In addition to S-nitrosylation, we documented both in vitro and in vivo widespread nitration of tyrosine residues of cellular proteins in response to NO-ASA. Our results suggest that the increased intracellular NO levels following treatment with NO-ASA modulate cell signaling by chemically modifying key protein members of signaling cascades. We speculate that S-nitrosylation and tyrosine nitration are responsible, at least in part, for the inhibitory growth effect of NO-ASA on cancer cell growth and that this may represent a general mechanism of action of NO-releasing agents.Experimental Cell Research 03/2011; 317(10):1359-67. · 3.56 Impact Factor
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ABSTRACT: Indometacin, an inhibitor of cyclooxygenase-2 (COX-2), has been shown to exert anticancer effects in a variety of cancers. However, the effect and mechanism of indometacin on high glucose (HG)-induced proliferation and invasion of pancreatic cancer (PC) cells remain unclear. Multiple lines of evidence suggest that a large portion of pancreatic cancer (PC) patients suffer from either diabetes or HG which contributing PC progression. In this study, we report that indometacin down-regulated HG-induced proliferation and invasion via up-regulating E-cadherin but not COX-2 in PC cells. Additionally, the E-cadherin transcriptional repressors, Snail and Slug, were also involved in the process. In addition, the proliferation and invasion of PC cells, incubated in HG medium and treated with indometacin were significantly increased when E-cadherin was knocked down (Si-E-cad). Moreover, the protein levels of MMP-2, MMP-9 and VEGF were increased in PC cells transfected with Si-E-cad. Finally, the activation of the PI3K/AKT/GSK-3β signaling pathway was demonstrated to be involved in indometacin reversing HG-induced cell proliferation and invasion in PC cells. In conclusion, these results suggest that indometacin plays a key role in down-regulating HG-induced proliferation and invasion in PC cells. Our findings indicate that indometacin could be used as a novel therapeutic strategy to treat PC patients who simultaneously suffer from diabetes or HG.Current Medicinal Chemistry 08/2013; · 3.72 Impact Factor