Colon Adenocarcinoma Cells (colon + adenocarcinoma_cell)

Distribution by Scientific Domains
Distribution within Medical Sciences

Selected Abstracts

Enzymatic oxidation products of spermine induce greater cytotoxic effects on human multidrug-resistant colon carcinoma cells (LoVo) than on their wild-type counterparts

Annarica Calcabrini
Abstract The occurrence of resistance to cytotoxic agents in tumor cells, associated with several phenotypic alterations, is one of the major obstacles to successful anticancer chemotherapy. A new strategy to overcome MDR of human cancer cells was studied, using BSAO, which generates cytotoxic products from spermine, H2O2 and aldehyde(s). The involvement of these products in causing cytotoxicity was investigated in both drug-sensitive (LoVo WT) and drug-resistant (LoVo DX) colon adenocarcinoma cells. Evaluation of clonogenic cell survival showed that LoVo DX cells are more sensitive than LoVo WT cells. Fluorometric assay and treatments performed in the presence of catalase demonstrated that the cytotoxicity was due mainly to the presence of H2O2. Cytotoxicity was eliminated in the presence of both catalase and ALDH. Transmission electron microscopic observations showed more pronounced mitochondrial modifications in drug-resistant than in drug-sensitive cells. Mitochondrial functionality studies performed by flow cytometry after JC-1 labeling revealed basal hyperpolarization of the mitochondrial membrane in LoVo DX cells. After treatment with BSAO and spermine, earlier and higher mitochondrial membrane depolarization was found in LoVo DX cells than in drug-sensitive cells. In addition, higher basal ROS production in LoVo DX cells than in drug-sensitive cells was detected by flow-cytometric analysis, suggesting increased mitochondrial activity in drug-resistant cells. Our results support the hypothesis that mitochondrial functionality affects the sensitivity of cells to the cytotoxic enzymatic oxidation products of spermine, which might be promising anticancer agents, mainly against drug-resistant tumor cells. © 2002 Wiley-Liss, Inc. [source]

The cytotoxic effect of Bowman,Birk isoinhibitors, IBB1 and IBBD2, from soybean (Glycine max) on HT29 human colorectal cancer cells is related to their intrinsic ability to inhibit serine proteases

Alfonso Clemente
Abstract Bowman,Birk inhibitors (BBI) from soybean and related proteins are naturally occurring protease inhibitors with potential health-promoting properties within the gastrointestinal tract. In this work, we have investigated the effects of soybean BBI proteins on HT29 colon adenocarcinoma cells, compared with non-malignant colonic fibroblast CCD-18Co cells. Two major soybean isoinhibitors, IBB1 and IBBD2, showing considerable amino acid sequence divergence within their inhibitory domains, were purified in order to examine their functional properties, including their individual effects on the proliferation of HT29 colon cancer cells. IBB1 inhibited both trypsin and chymotrypsin whereas IBBD2 inhibited trypsin only. Despite showing significant differences in their enzyme inhibitory properties, the median inhibitory concentration values determined for IBB1 and IBBD2 on HT29 cell growth were not significantly different (39.9±2.3 and 48.3±3.5,,M, respectively). The cell cycle distribution pattern of HT29 colon cancer cells was affected by BBI treatment in a dose-dependent manner, with cells becoming blocked in the G0,G1 phase. Chemically inactive soybean BBI had a weak but non-significant effect on the proliferation of HT29 cells. The anti-proliferative properties of BBI isoinhibitors from soybean reveal that both trypsin- and chymotrypsin-like proteases involved in carcinogenesis should be considered as potential targets of BBI-like proteins. [source]

Erythrodiol, a natural triterpenoid from olives, has antiproliferative and apoptotic activity in HT-29 human adenocarcinoma cells

M. Emília Juan
Abstract Erythrodiol is the precursor of pentacyclic triterpenic acids present in Olea Europaea. Although olive oil and some of its constituents are reported to have anticarcinogenic activities, erythrodiol has not been assessed in its cell biological functions in detail. We therefore determined its effects on cell growth and apoptosis in human colorectal carcinoma HT-29 cells. Proliferation, cytotoxicity, and apoptosis were measured by fluorescence-based techniques. Erythrodiol inhibited cell growth with an EC50 value of 48.8 ± 3.7 ,M without any cytotoxic effects in a concentration range up to 100 ,M. However, exposure of cells for 24 h to 50, 100, and 150 ,M erythrodiol increased caspase-3-like activity by 3.2-, 4.8-, and 5.2-fold over that in control cells. We here demonstrate for the first time that, in colon adenocarcinoma cells, erythrodiol exerts antiproliferative and proapoptotic activity. [source]

Alterations in Mitochondrial and Apoptosis-regulating Gene Expression in Photodynamic Therapy-resistant Variants of HT29 Colon Carcinoma Cells,

Xiao Yun Shen
ABSTRACT Photodynamic therapy (PDT) is a novel cancer therapy inducing irreversible photodamage to tumor tissue via photosensitizer-mediated oxidative cytotoxicity. The cellular and molecular responses associated with PDT are only partially understood. We have reported previously the generation of several photosensitizer-specific PDT-resistant cell variants of HT29 human colon adenocarcinoma cells by selecting cells from sequential PDT treatment using different photosensitizers. In this report, we describe the use of messenger RNA (mRNA) differential display to identify genes that were differentially expressed in the parental HT29 cells compared with their resistant variants. In comparison with parental HT29 cells, mRNA expression was increased in the PDT-resistant cell variants for BNIP3, estrogen receptor-binding fragmentassociated gene 9, Myh-1c, cytoplasmic dynein light chain 1, small membrane protein I and differential dependent protein. In contrast, expression in the PDT-resistant variants was downregulated for NNX3, human HepG2 3,region Mbol complementary DNA, glutamate dehydrogenase, hepatomaderived growth factor and the mitochondrial genes coding for 16S ribosomal RNA (rRNA) and nicotinamide adenine dinucleotide (NADH) dehydrogenase subunit 4. The reduction for mitochondrial 16S rRNA in the PDT-resistant variants was confirmed by Northern blotting, and the elevated expression of the proapoptotic BNIP3 in the PDT-resistant variants was confirmed by Northern and Western blotting analysis. We also examined the expression of some additional apoptosis-regulating genes using Western blotting. We show an increased expression of Bcl-2 and heat shock protein 27 and a downregulation of Bax in the PDT-resistant variants. In addition, the mutant p53 levels in the parental HT29 cells were reduced substantially in the PDT-resistant variants. We suggest that the altered expression in several mitochondria1 and apoptosisregulating genes contributes to PDT resistance. [source]

, -hederin potentiates 5-FU antitumor activity in human colon adenocarcinoma cells

Sok-Siya Bun
Abstract The aim of this study was to investigate the ability of , -hederin to improve the efficacy of widely prescribed 5-fluorouracil (5-FU) in a human colon adenocarcinoma model. Drug combinations of , -hederin and 5-FU using both fixed-concentration and combination index methods were performed in vitro in HT-29 cells. The results showed that , -hederin at sub-IC50 cytotoxic concentrations enhanced 5-FU cytotoxicity about 3.3-fold (p < 0.001). Simultaneous combination of , -hederin and 5-FU at their IC50 ratio showed either a synergistic effect at a moderate cytotoxic range (25% of cell growth inhibition) or an antagonistic effect at a high level of growth inhibition. The data indicate therefore that it is possible to optimize colorectal cancer cell sensitivity to 5-FU with , -hederin. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Ergosterol peroxide from an edible mushroom suppresses inflammatory responses in RAW264.7 macrophages and growth of HT29 colon adenocarcinoma cells

M Kobori
Background and purpose: 5,,8,-Epidioxy-22E -ergosta-6, 22-dien-3,-ol (ergosterol peroxide) is a major antitumour sterol produced by edible or medicinal mushrooms. However, its molecular mechanism of action has yet to be determined. Here, we examine the anticancer and anti-inflammatory effects of ergosterol peroxide. Experimental approach: After treating RAW264.7 macrophages with LPS and purified ergosterol peroxide or ergosterol, we determined LPS-induced inflammatory cytokines, nuclear DNA binding activity of transcription factors and phosphorylation of MAP kinases (MAPKs). HT29 colorectal adenocarcinoma cells were treated with ergosterol peroxide for 5 days. To investigate the antitumour properties of ergosterol peroxide, we performed DNA microarray and RT-PCR analyses and determined the reactive oxygen species (ROS) in HT29 cells. Key results: Ergosterol peroxide suppressed LPS-induced TNF-, secretion and IL-1,/, expression in RAW264.7 cells. Ergosterol peroxide and ergosterol suppressed LPS-induced DNA binding activity of NF-,B and C/EBP,, and inhibited the phosphorylation of p38, JNK and ERK MAPKs. Ergosterol peroxide down-regulated the expression of low-density lipoprotein receptor (LDLR) regulated by C/EBP, and HMG-CoA reductase (HMGCR) in RAW264.7 cells. In addition, ergosterol peroxide showed cytostatic effects on HT29 cells and increased intracellular ROS. Furthermore, ergosterol peroxide induced the expression of oxidative stress-inducible genes, and the cyclin-dependent kinase inhibitor CDKN1A, and suppressed STAT1 and interferon-inducible genes. Conclusion and Implication: Our results suggest that ergosterol peroxide and ergosterol suppress LPS-induced inflammatory responses through inhibition of NF-,B and C/EBP, transcriptional activity, and phosphorylation of MAPKs. Moreover, ergosterol peroxide appears to suppress cell growth and STAT1 mediated inflammatory responses by altering the redox state in HT29 cells. British Journal of Pharmacology (2007) 150, 209,219. doi:10.1038/sj.bjp.0706972 [source]

Activation of ASC induces apoptosis or necrosis, depending on the cell type, and causes tumor eradication

CANCER SCIENCE, Issue 8 2010
Kou Motani
The adaptor protein ASC (also called TMS1) links certain NLR proteins (e.g., NLRC4, NLRP3) and caspases. It is involved in the chemosensitivity of tumor cells and inflammation. Here, we found that ASC activation using NLRC4 mimicry or an autoinflammatory disease-associated NLRP3 mutant induced necrosis in COLO205 colon adenocarcinoma cells, but induced caspase-8-dependent apoptosis in NUGC-4 stomach cancer cells. As the Fas ligand induced caspase-8-dependent apoptosis in COLO205 cells, caspase-8 was intact in this cell line. ASC-mediated necrosis was preceded by lysosomal leakage, and diminished by inhibitors for vacuolar H+ -ATPase, cathepsins, and calpains but not by inhibitors for caspase-8, or aspartic proteases, suggesting that lysosomes and certain proteases were involved in this process. Finally, growing tumors of transplanted human cancer cells in nude mice were eradicated by the activation of endogenous ASC in the tumor cells, irrespective of the form of cell death. Thus, ASC mediates distinct forms of cell death in different cell types, and is a promising target for cancer therapy. (Cancer Sci 2010) [source]