Colon cancer cells with high invasive potential are susceptible to induction of apoptosis by a selective COX-2 inhibitor

Anticancer Effect of PtIIPHENSS, PtII5MESS, PtII56MESS and Their Platinum(IV)-Dihydroxy Derivatives against Triple-Negative Breast Cancer and Cisplatin-Resistant Colorectal Cancer

Development of resistance to cisplatin, oxaliplatin and carboplatin remains a challenge for their use as chemotherapies, particularly in breast and colorectal cancer. Here, we compare the anticancer effect of novel complexes [Pt(1,10-phenanthroline)(1S,2S-diaminocyclohexane)](NO3)2 (PtIIPHENSS), [Pt(5-methyl-1,10-phenanthroline)(1S,2S-diaminocyclohexane)](NO3)2 (PtII5MESS) and [Pt(5,6-dimethyl-1,10-phenanthroline)(1S,2S-diaminocyclohexane)](NO3)2 (PtII56MESS) and their platinum(IV)-dihydroxy derivatives with cisplatin. Complexes are greater than 11-fold more potent than cisplatin in both 2D and 3D cell line cultures with increased selectivity for cancer cells over genetically stable cells. ICP-MS studies showed cellular uptake occurred through an active transport mechanism with considerably altered platinum concentrations found in the cytoskeleton across all complexes after 24 h. Significant reactive oxygen species generation was observed, with reduced mitochondrial membrane potential at 72 h of treatment. Late apoptosis/necrosis was shown by Annexin V-FITC/PI flow cytometry assay, accompanied by increased sub-G0/G1 cells compared with untreated cells. An increase in S and G2+M cells was seen with all complexes. Treatment resulted in significant changes in actin and tubulin staining. Intrinsic and extrinsic apoptosis markers, MAPK/ERK and PI3K/AKT activation markers, together with autophagy markers showed significant activation of these pathways by Western blot. The proteomic profile investigated post-72 h of treatment identified 1597 MDA-MB-231 and 1859 HT29 proteins quantified by mass spectroscopy, with several differentially expressed proteins relative to no treatment. GO enrichment analysis revealed a statistically significant enrichment of RNA/DNA-associated proteins in both the cell lines and specific additional processes for individual drugs. This study shows that these novel agents function as multi-mechanistic chemotherapeutics, offering promising anticancer potential, and thereby supporting further research into their application as cancer therapeutics.

Melatonin and andrographolide synergize to inhibit the colospheroid phenotype by targeting Wnt/beta-catenin signaling

β-catenin signaling, and angiogenesis are associated with colospheroid (CSC), development. CSCs, spheroids derived from colon cancer cells, are responsible for metastasis, drug resistance, and disease recurrence. Whether dysregulating β-catenin and inhibiting angiogenesis reduce CSC growth is unknown. In this study, the molecular mechanism of CSC growth inhibition was evaluated using a novel combination of melatonin (MLT) and andrographolide (AGP). These drugs have anticarcinogenic, antioxidant, and antimetastatic properties. CSCs were obtained from two metastatic colon cancer cell lines (HT29 and HCT-15). The viability and stemness were monitored (FDA propidium iodide staining and immunoblot for CD44, CD133, Nanog, Sox2, and Oct4). The drug combination synergistically diminished stemness via increased reactive oxygen species (ROS) levels, reduced mitochondrial membrane potential and ATP level. MLT + AGP induced cell death by inhibiting β-catenin expression and its downregulatory signals, Cyclin D1, c-Myc. MLT + AGP treated cells exhibited translocation of phospho-β-catenin to the nucleus and dephosphorylated-β-catenin. Downregulation of β-catenin activation and its transcription factors (TCF4 and LEF1) and GTP binding/G-protein related activity were found in the dual therapy. Angiogenic inhibition is consistent with downregulation of VEGF messenger RNA transcripts (VEGF189), phosphorylated VEGF receptor protein expression, matrigel invasion, and capillary tube inhibition. In vivo, the intravenous injection of MLT + AGP slowed HT29 metastatic colon cancer. Histopathology indicated significant reduction in microvascular density and tumor index. Immunohistochemistry for caspase 7, and β-catenin found increased apoptosis and downregulation of β-catenin signals. The mechanism(s) of decreased colospheroids growth were the inhibition of the Wnt/β-catenin pathway. Our results provide a rationale for using MLT in combination with AGP for the inhibition of CRCs.

Diclofenac down-regulates COX-2 induced expression of CD44 and ICAM-1 in human HT29 colorectal cancer cells

Cyclooxygenase-2 (COX-2) is expressed in a variety of human colorectal cancer cells and can contribute to carcinogenesis. This study aimed to investigate the effect of diclofenac (DCF), a selective COX-2 inhibitor, on cell adhesion molecules and apoptosis in human colon adenocarcinoma cells. Levels of homing cell adhesion molecule (H-CAM, CD44), intercellular adhesion molecule-1 (ICAM-1, CD54), vascular cell adhesion molecule-1 (VCAM-1, CD106), and epithelial cell adhesion molecule (EpCAM, CD326) were evaluated in cancer cells overexpressing (HT29) or not expressing (HCT116) COX-2. Cell viability was determined by MTT assay, COX-2 protein levels and activity were assessed by immunofluorescence and fluorometric analysis, respectively. Endogenous levels of polyunsaturated fatty acids (PUFAs) were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) while expression of cell adhesion molecules was analyzed by flow cytometry. Annexin V-FITC/propidium iodide-labelling and fluorometric caspase-3 activity measurements were carried out to determine apoptosis. Flow cytometry analysis revealed that the percentage of CD44 and ICAM-1 staining in HCT116 cells was significantly lower compared to HT29 cells. In HT29 cells, phorbol 12-myristate 13-acetate (PMA) induced COX-2 expression and increased CD44 and ICAM-1 levels were down-regulated by diclofenac. Stimulation of COX-2 activity in HT29 cells via PMA significantly decreased diclofenac associated increase in PUFA levels. Treatment with both diclofenac and PMA significantly increased the number of apoptotic cells and caspase-3 activity in colon adenocarcinoma cells compared to control groups. In conclusion, diclofenac's effect to retard colorectal tumor growth and metastasis occurs in COX-2 overexpressing colon cancer cells by increased apoptosis and decreased expression of CD44 and ICAM-1.

Regulatory T Cells and Cancer: A Two-Sided Story

Regulatory T cells (Tregs) play pivotal roles in limiting the duration and magnitude of immune response against infectious agents and self-antigens. This is accomplished through contact-dependent and -independent mechanisms that involve crosstalk between Treg cells and other immune and tissue-specific cell types. The same machinery is employed by Tregs to regulate immune responses to cancer, limiting both pro-tumor inflammation and anti-tumor immunity. Factors produced by Treg cells also act directly on transformed epithelial cells and exert opposing effects during different stages of cancer development. Therefore, the immune regulatory cell population serves as a double-edged sword for the development, progression, and treatment of cancers. In this review, we summarize current knowledge on the roles of Treg lymphocytes during cancer development, as well as the underlying cellular and molecular mechanism.

Tumor-Elicited Inflammation and Colorectal Cancer

The link between chronic inflammation and cancer has long been suspected, due to the pioneering work of Rudolf Virchow over 150 years ago. Yet the causal relationship between inflammation and cancer was only deciphered in the past decade or so, using animal models of various cancers. Up to 20% of all human cancers result from chronic inflammation and persistent infections. Proinflammatory cytokines and tumor-infiltrating myeloid and immune cells play critical roles in almost every developmental stages of inflammation-induced cancers, from initiation, promotion, and progression to malignant metastasis. However, even in cancers with no preceding inflammation, inflammatory cells infiltrate tumor stroma and contribute to cancer development. Such "tumor-elicited inflammation" further emphasizes the importance of inflammation in different types of cancers, including that of the colon. In this review, we summarize our current knowledge of the function and induction mechanisms of inflammatory cytokines during colorectal cancer development, and hope to provide insight into the development of novel anticancer therapies by modulating tumor-elicited inflammation.

Genetic unraveling of colorectal cancer

Colorectal cancer is a common disease in both men and women (being the third most common cancer in men and the second most common among women) and thus represents an important and serious public health issue, especially in the western world. Although it is a well-established fact that cancers of the large intestine produce symptoms relatively earlier at a stage that can be easily cured by resection, a large number of people lose their lives to this deadly disease each year. Recent times have seen an important change in the incidence of colorectal cancer in different parts of the world. The etiology of colorectal cancer is multifactorial and is likely to involve the actions of genes at multiple levels along the multistage carcinogenesis process. Exhaustive efforts have been made out in the direction of unraveling the role of various environmental factors, gene mutations, and polymorphisms worldwide (as well as in Kashmir-"a valley of gastrointestinal cancers") that have got a role to play in the development of this disease so that antitumor drugs could be developed against this cancer, first, and, finally, the responsiveness or resistance to these agents could be understood for combating this global issue.

Nimesulide inhibits the proliferation of HepG2 by up-regulation of Smad4

Objectives:

Hepatocellular carcinoma (HCC) is receiving increased attention. This study was designed to investigate the effect of selective Cyclooxygenase-2 (COX-2) inhibitor, nimesulide, on the expression of Smad4 in human hepatocellular carcinoma HepG2.

Materials and Methods:

HepG2 cells were incubated in various concentrations of nimesulide (25, 50, 100, 200, 400 μmol/L) to detect the effect of proliferation by MTS. The apoptosis of HepG2 was determined by TUNEL; fluorescence microscope was used to observe the expression of Smad4.

Results:

The result showed that nimesulide inhibited the proliferation of HepG2 cell in a concentrations-dependent manner, and promoted the karyopyknosis and fragmentation of HepG2 cell nucleus, induced its apoptosis, the number of fluorescence labeling of Smad4 in Nimesulide group was higher than control group (P<0.05).

Conclusions:

Nimesulide inhibits the proliferation and promotes apoptosis of HepG2 by up-regulation of Smad4 in HepG2.

Inhibition of COX-2 in colon cancer modulates tumor growth and MDR-1 expression to enhance tumor regression in therapy-refractory cancers in vivo

Higher cyclooxygenase 2 (COX-2) expression is often observed in aggressive colorectal cancers (CRCs). Here, we attempt to examine the association between COX-2 expression in therapy-refractory CRC, how it affects chemosensitivity, and whether, in primary tumors, it is predictive of clinical outcomes. Our results revealed higher COX-2 expression in chemoresistant CRC cells and tumor xenografts. In vitro, the combination of either aspirin or celecoxib with 5-fluorouracil (5-FU) was capable of improving chemosensitivity in chemorefractory CRC cells, but a synergistic effect with 5-FU could only be demonstrated with celecoxib. To examine the potential clinical significance of these observations, in vivo studies were undertaken, which also showed that the greatest tumor regression was achieved in chemoresistant xenografts after chemotherapy in combination with celecoxib, but not aspirin. We also noted that these chemoresistant tumors with higher COX-2 expression had a more aggressive growth rate. Given the dramatic response to a combination of celecoxib + 5-FU, the possibility that celecoxib may modulate chemosensitivity as a result of its ability to inhibit MDR-1 was examined. In addition, assessment of a tissue microarray consisting of 130 cases of CRCs revealed that, in humans, higher COX-2 expression was associated with poorer survival with a 68% increased risk of mortality, indicating that COX-2 expression is a marker of poor clinical outcome. The findings of this study point to a potential benefit of combining COX-2 inhibitors with current regimens to achieve better response in the treatment of therapy-refractory CRC and in using COX-2 expression as a prognostic marker to help identify individuals who would benefit the greatest from closer follow-up and more aggressive therapy.

Cyclooxygenase inhibitors: scope of their use and development in cancer chemotherapy

The traditional nonsteroidal anti-inflammatory drugs (NSAIDs) exert their effect by inhibition of cyclooxygenase-1 (COX-1) as well as COX-2 enzymes. As COX-1 is responsible for maintaining normal biological functions, the nonselective inhibition of these enzymes caused side effects including gastrointestinal (GI) problems. Recently developed selective COX-2 inhibitors could reduce these adverse effects, but the evidence of cardiovascular side effects including an increased risk of myocardial infarction began to emerge, and some of the COX-2 inhibitors were eventually withdrawn from the market and this led to the downfall of this research. So, the discovery of novel COX-2 inhibitors with their safety profile became the biggest challenge in pharmaceutical research. However, recent mechanistic and clinical studies revolutionized this area by indicating the fact that COX-2 is involved in apoptosis resistance, angiogenesis, and tumor progression. Epidemiological data suggest that selective COX-2 inhibitors might prevent the development of cancers. Moreover, COX-2 is found to be overexpressed in many cancers thus making it an attractive therapeutic target for the prevention and treatment of a number of malignancies. The purpose of this review is to focus on the medicinal chemistry aspects of COX-2 inhibitors in cancer chemotherapy and recent reports on these inhibitors as anticancer agents. We attempted to cover only the COX inhibitors that showed anticancer activity, although a number of potent COX-2 inhibitors have been reported without their anticancer effects. Furthermore, structure-activity relationships (SAR) of different classes of compounds for COX-2 inhibition as well as anticancer activity, and their future applications are discussed.

The flavouring phytochemical 2-pentanone reduces prostaglandin production and COX-2 expression in colon cancer cells

Many phytochemicals found in the diet may prevent colon carcinogenesis by affecting biochemical processes in the colonic mucosa. Inflammation and subsequent elevation of the enzyme cyclooxygenase-2 (COX-2) are two such factors involved in the development of colon cancer, and inhibition of these processes could be important targets for chemoprevention. We have previously shown COX-2 inhibitory activity locally in the colon; e.g. in human fecal water from a group of vegetarians. In this study we focus on 2-pentanone, a frequently occurring compound in common foods such as banana and carrot. The aim was to study the inhibitory effects on prostaglandin production and COX-2 protein expression in tumour necrosis factor-alpha stimulated colon cancer cells (HT29) by radioimmunoassay and Western blotting. 2-Pentanone inhibited both prostaglandin production and COX-2 protein expression in human colon cancer cells. A concentration of 400 mumol/l 2-pentanone inhibited the prostaglandin production by 56.9+/-12.9% which is in the same range as the reference compound NS398 (59.8+/-7.6%). The two highest concentrations of 2-pentanone were further analyzed by Western blot, and 400 micromol/l and 200 micromol/l 2-pentanone resulted in a 53.3+/-9.6% and +/-27.1% reduction of the COX-2 protein levels respectively. Further studies on flavouring compounds, for example 2-pentanone, as colon cancer chemopreventives would be very valuable, and such results may contribute to future dietary recommendations.

Effect of a selective nonsteroidal anti-inflammatory drug, celecoxib, on the reproductive function of female mice

BACKGROUND

The aim of the present study was to determine if long-term use of a cyclooxygenase-2 (COX-2) inhibitor affects fertility or ovulation in female mice.

METHODS

Twenty-four female mice, 25 days of age, were given a selective COX-2 inhibitor: 3 mg/kg celecoxib (n = 8), 5 mg/kg celecoxib (n = 8),or placebo (n = 8) in a random fashion. Eight female mice, 10-11 weeks old, given 3 mg/kg celecoxib (n = 4) or placebo (n = 4) were subjected to continuous mating studies.

RESULTS

Results from the 24 mice (n = 8 for each group) showed that oocyte number was not significantly different between female mice treated with either 3 mg/kg or 5 mg/kg celecoxib and placebo (21.4 +/- 2.5, 21.5 +/- 3.3, 23.3 +/- 3.8, respectively). From the continuous mating study, the litter size of female mice treated with celecoxib was not significantly different (8.2 +/- 1.3 pups/litter) compared to those treated with placebo (8.3 +/- 1.2 pups/litter). In addition, female mice treated with celecoxib had an average of 2.8 +/- 0.5 litters in a 12-week period, which was similar to female mice treated with placebo (3.0 +/- 0.8 litters/female).

CONCLUSION

This study suggests that use of low-dose (<or= 5 mg/kg) selective COX-2 inhibitor in a mouse model does not significantly impair the female reproductive function.

RhoA Mediates Cyclooxygenase-2 Signaling to Disrupt the Formation of Adherens Junctions and Increase Cell Motility

Cyclooxygenase-2 (COX-2) represents an important target for treatment and prevention of colorectal cancer. Although COX-2 signaling is implicated in promoting tumor cell growth and invasion, the molecular mechanisms that mediate these processes are largely unknown. In this study, we show that the RhoA pathway mediates COX-2 signaling to disrupt the formation of adherens junctions and increase cell motility. Disruption of adherens junctions promotes tumor cell invasion and metastasis and is often associated with tumor progression. We detected high levels of RhoA activity in HCA-7 colon carcinoma cells that constitutively express COX-2. Inhibition of COX-2 significantly reduced the levels of RhoA activity in HCA-7 cells, suggesting that constitutive expression of COX-2 stimulates RhoA activity. Interestingly, inhibition of COX-2 or silencing of COX-2 expression with small interfering RNA (siRNA) stimulated the formation of adherens junctions, concomitant with increased protein levels of E-cadherin and alpha-catenin. Furthermore, inhibition of RhoA or silencing of RhoA expression with siRNA increased the levels of E-cadherin and alpha-catenin. Inhibition of Rho kinases (ROCK), the RhoA effector proteins, also increased levels of E-cadherin and alpha-catenin and stimulated formation of adherens junctions. The motility of HCA-7 cells was significantly decreased when COX-2 or RhoA was inhibited. Therefore, our data reveal a novel molecular mechanism that links COX-2 signaling to disrupt the formation of adherens junctions; COX-2 stimulates the RhoA/ROCK pathway, which reduces levels of E-cadherin and alpha-catenin leading to disruption of adherens junction formation and increased motility. Understanding of COX-2 downstream signaling pathways that promote tumor progression is crucial for the development of novel therapeutic strategies.

Combination of cyclooxygenase-2 inhibitors and oxaliplatin increases the growth inhibition and death in human colon cancer cells

The cyclooxygenase-2 (COX-2) protein is highly expressed in a variety of human cancers and has been reported to promote tumor growth. Non-steroidal anti-inflammatory drugs such as etodolac and celecoxib have been shown to inhibit COX-2 activity and may play a role in the chemoprevention of cancer. Oxaliplatin is a third-generation platinum compound that exhibits a different spectrum of activity compared with cisplatin. Other cisplatin-resistant tumors can still respond to oxaliplatin. However, the anticancer ability of the combination of COX-2 inhibitors and oxaliplatin is still unknown. In this study, we investigated the effects of combination of COX-2 inhibitors and oxaliplatin on the cell growth and survival in human colon cancer cells. Treatments with etodolac (0.3-0.5 mM) or celecoxib (20-80 microM) for 24 h concentration-dependently induced the cytotoxicity in the RKO colon carcinoma cells. Etodolac and celecoxib did not alter the COX-2 protein levels but inhibited its enzyme activity to reduce prostaglandin E2 production. Furthermore, the cell survival was concentration-dependently decreased following oxaliplatin (1-100 microM, 24 h) treatment. Combination of oxaliplatin and etodolac additively increased the death and growth inhibition of RKO cells. Survivin, an inhibitor protein of apoptosis, mediates anti-apoptosis and promotes cell division in cancer cells. Oxaliplatin or COX-2 inhibitors significantly decreased the levels of survivin proteins. Moreover, survivin proteins were markedly diminished following co-treatment with oxaliplatin and etodolac. Together, this is the first report that combination of COX-2 inhibitors and oxaliplatin can increase the reduction of survivin protein expression, growth inhibition, and death in human colon cancer cells.

Bifidobacterium Lactis sp. 420 up-regulates cyclooxygenase (Cox)-1 and down-regulates Cox-2 gene expression in a Caco-2 cell culture model

Cyclooxygenases (Cox) -1 and -2 play important roles in gastrointestinal health; chronic overexpression of Cox-2 is associated with inflammatory and cancerous disease, whereas Cox-1 is expressed constitutively. We studied the effects of two probiotic (Bifidobacterium lactis sp. 420 and Lactobacillus acidophilus) and two control microorganisms (Escherichia coli and Salmonella enteritidis) and four microbial metabolites (acetate, butyrate, lactate and propionate) on the expression levels of the Cox isoforms in the enterocyte-like cell line Caco-2. Butyrate, which is anticarcinogenic, resulted in an 85% down-regulation of Cox-2 and a 37-fold increase in Cox-1 transcription. Propionate gave similar results (72% reduction of Cox-2, 23-fold induction of Cox-1), but lactate and acetate had no effect on Cox expression profile. Bifidobacterium sp. 420, which produces acetate and lactate but no butyrate or propionate, shared the Cox-1-increasing and Cox-2-silencing properties of butyrate and propionate, whereas L. acidophilus was similar to E. coli and S. enteritidis in having no effect on the Cox-1/Cox-2 ratio. For the first time, we therefore demonstrate evidence for a direct relationship between a probiotic bacterial strain and host Cox expression profile, suggesting that modulation of Cox expression may be an important factor in the potential anti-inflammatory and anticarcinogenic properties of some probiotics.

Selective inhibition of cyclooxygenase-2 inhibits colon cancer cell adhesion to extracellular matrix by decreased expression of beta1 integrin

High level expression of cyclooxygenase (COX)-2 is reported in 80-90% of colorectal adenocarcinomas. In the recent years, selective inhibitors of COX-2 have been developed, and are shown to effectively protect against cancer development and progression. Colon cancer cells, as well as the epithelial cells in general, are dependent on appropriate interactions with the extracellular matrix (ECM) proteins to achieve a number of important functions, such as proliferation, differentiation, invasion and survival. These interactions are mediated via a family of cell-surface receptors called integrins, which interact with cytoskeletal proteins on the cytoplasmic side of the plasma membrane and thereby provide a link between the ECM and the cytoskeleton. In the present study, a high-COX-2 (high level COX-2 expression) colon cancer cell line, HT-29, and a low-COX-2 (low level COX-2 expression), DLD-1, were used to investigate the anticolon cancer effect of the selective COX-2 inhibitor, JTE-522. Moreover, to clarify its mechanisms of action, we focused especially on the ability to adhere to and to migrate on ECM. We could clearly demonstrate that, in addition to the decrease of the proliferative activity, JTE-522 caused a dose-dependent decrease in both the ability of colon cancer cells to adhere to and to migrate on ECM. These effects were, at least in part, dependent on the down-regulation of beta1-integrin expression, which was evident in HT-29, the high-COX-2 colon cancer cells, but not the low-COX-2, DLD-1. In addition, prostaglandin E2 almost completely reversed the effect of JTE-522, strongly suggesting the involvement of a COX-2-dependent pathway. In conclusion, for the first time, we could demonstrate the down-regulation of beta1 integrin caused by COX-2 inhibition, with consequent impairment of the ability of cancer cells to adhere to and to migrate on ECM, which are crucial steps for cancer metastases to develop.

Sequence-dependent effect of a cyclooxygenase-2 inhibitor on topoisomerase I inhibitor and 5-fluorouracil-induced cytotoxicity of colon cancer cells

Selective cyclooxygenase-2 (COX-2) inhibitors have been found to induce anti-proliferative and apoptotic activity in many cancer cells. However, interaction between COX-2 inhibitors and other chemotherapeutic agents remains to be determined. We investigated the interactive effects of a selective COX-2 inhibitor, etodolac, in combination with 5-fluorouracil (5-FU) or SN-38 (active metabolite of irinotecan) on colon cancer cell lines, HT29 and SW620, in simultaneous and sequential administration schedules. Isobologram analysis demonstrated that etodolac in combination with 5-FU or SN-38 according to a simultaneous schedule resulted in only an additive effect; however, synergism was achieved in a sequential schedule. Apoptosis induction in both cell lines was also significantly increased after sequential treatment with etodolac followed by either 5-FU or SN-38 compared to that after simultaneous treatment with etodolac and either 5-FU or SN-38. Our study suggests apoptosis-inducing synergism resulted from administration of etodolac and either 5-FU or SN-38 sequentially, but not simultaneously.

Cytotoxic effect of glycoprotein isolated from Solanum nigrum L. through the inhibition of hydroxyl radical-induced DNA-binding activities of NF-kappa B in HT-29 cells

Solanum nigrum L. (SNL) has been traditionally used as an herbal plant for a long time. In the present study, SNL glycoprotein showed a dose-dependent radical scavenging activity on radicals, including 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, hydroxyl radical (OH), and superoxide anion (O(2)(-)). When the HT-29 cells were treated with 60μg/ml SNL glycoprotein, the cytotoxic effect was induced in a time-dependent manner. More specifically, it was more than 60% (P<0.01) after 4h, compared to the control. On the other hand, the cells treated with 100mU/ml glucose oxidase (GO) to generate the OH radical showed a cancer resistance up to 12h. Furthermore, the addition of GO to the SNL glycoprotein caused a strong cytotoxic effect, rather than a radical scavenging effect. Interestingly, when the cells were exposed to 100mU/ml GO for 4h, the DNA-binding activity of nuclear factor-kappa B (NF-κB) was increased 4.15-fold (P<0.01) compared to the control, whereas 40μg/ml SNL glycoprotein completely blocked the DNA-binding activity of OH radical-induced NF-κB by electrophoretic mobility shift assays (EMSAs). Apoptosis, according to the apoptosis assay, increased as a result of treatment with 40μg/ml SNL glycoprotein in a time-dependent manner, whereas they were weakly induced by GO in the cells. Consequently, the SNL glycoprotein may induce apoptosis through the inhibition of NF-κB activation, induced by oxidative stress in HT-29 cells.