Antiproliferative activity of vitexin-2-<Emphasis Type="Italic">O</Emphasis>-xyloside and avenanthramides on CaCo-2 and HepG2 cancer cells occurs through apoptosis induction and reduction of pro-survival mechanisms

Purpose

CaCo-2 colon cancer cells and HepG2 liver cancer cells represent two malignant cell lines, which show a high resistance to apoptosis induced by the conventional anticancer drugs. Vitexin-2-O-xyloside (XVX) and avenanthramides (AVNs) are naturally occurring dietary agents from Beta vulgaris var. cicla L. and Avena sativa L., respectively. The aim of this work was to evaluate the antiproliferative effects and the reduction of the pro-survival mechanisms exerted by XVX and AVNs, used individually and in combination, in CaCo-2 and HepG2 cancer cells.

Methods

XVX and AVNs were isolated by liquid chromatography and characterized by HPLC–PDA–MS. The XVX and AVN antiproliferative effects were evaluated through sulforhodamine B method, while their pro-apoptotic effects through caspase activity assays. RTqPCR was used to investigate the modulation of the pro-survival factors baculoviral inhibitor of apoptosis repeat-containing 5 (BIRC5), hypoxia inducible factor 1 A (HIF1A), and vascular endothelial growth factor A (VEGFA). Cellular antioxidant activity (CAA) was investigated by means of DCFH-DA assay, whereas chemical antioxidant capacity was evaluated by the ORAC method.

Results

XVX and AVNs, both individually and in combination, inhibited the proliferation of CaCo-2 and HepG2 cancer cells, through activation of caspases 9, 8, and 3. XVX and AVNs downregulated the pro-survival genes BIRC5, HIF1A, and VEGFA. The CAA assay showed that AVNs exhibited strong antioxidant activity inside both CaCo-2 and HepG2 cells.

Conclusions

The antiproliferative activity of the XVX?+?AVNs mixture represents an innovative treatment, which is effective against two types of cancer cells characterized by high resistance to the conventional anticancer drugs.

     

Gastrointestinal stability of urolithins: an in vitro approach

Purpose

Urolithins are bioactive ellagitannin-derived metabolites showing a wide phenotypic variation in their production by the gut microbiota. This work represents a first in vitro step toward the development of new strategies focused on the oral supplementation of urolithins with the aim of overcoming their selective production and making their putative health benefits available for the whole population.

Methods

In order to study their gastrointestinal stability, urolithin A, urolithin B, and urolithin B-glucuronide, as well as ellagic acid, were subjected to a simulated gastrointestinal digestion model consisting of oral, gastric, and pancreatic steps followed by a 24-h fecal fermentation. The effect of the entero-hepatic recirculation on urolithin B-glucuronide, a phase II metabolite, was also investigated.

Results

Urolithin B was the molecule able to resist to a greater extent the conditions of the gastrointestinal tract, while urolithin A and ellagic acid were drastically unstable during the colonic step. Conjugation with glucuronic acid, ideally occurring in the liver, conferred to urolithin B an increased stability, which may be interesting in the framework of entero-hepatic recirculation.

Conclusion

This set of experiments lets hypothesize that orally supplemented urolithins may come into contact with the colonic epithelium and become accessible for uptake or exert local anti-inflammatory activity, overcoming the limitations of enterotypes unable to convert ellagitannins into these putatively beneficial metabolites.

     

Synthesis, characterization and cytotoxicity of some novel 1,3-disubstituted-2,3-dihydro-2-iminobenzimidazoles

Some new 1,3-disubstituted-2,3-dihydro-2-iminobenzimidazoles were synthesized using 1-(un)substituted-2-aminobenzimidazoles as precursors in order to determine their cytotoxicity. The structures of the compounds were confirmed by IR, ¹H NMR, ¹³C NMR and elemental analysis.Compounds 4, 7-11 and 13-14 were evaluated for their cytotoxical effect on two cancer cell lines: human colorectal cancer cell line HT-29, breast cancer cells MDA-MB-231 and as well as normal spleen cells. The distinctly marked antiproliferative activity of 1,3-bis(3-phenylpropyl-1)-1,3-dihydro-2H-benzimidazol-2-imine hydro bromide 7, N-(aminopropyl)-2-(3-{2-[(aminopropyl)-amino]-2-oxoethyl}-2-imino-2,3-dihydro-1H-benzimidazol-1-yl)acetamide 9 and 1,3-bis[2-(4-methylpiperazin-1-yl)-2-oxoethyl]-2,3-dihydro-2H-benzimidazol-2-imine 11 against human colorectal cancer cell line HT-29 was ascertained and the calculated IC₅₀ were 9.26, 0.56 and 0.013 nM respectively. Compounds 4, 9, 10 and 13 exhibited relative high cytotoxic activity against MDA-MB-231 cells. The calculated IC₅₀ values were in the range 0.123-1.65 nM. All tested compounds excluding compound 1,3-bis[2-(4-methylpiperazin-1-yl)-2-oxoethyl]-2,3-dihydro-2H-benzimidazol-2-imine (11) revealed proliferative activities to normal spleen cells. The computed EC₅₀ values varied from 0.05 to 16.91 nM.     

Andrographolide Exhibits Anticancer Potential Against Human Colon Cancer Cells by Inducing Cell Cycle Arrest and Programmed Cell Death via Augmentation of Intracellular Reactive Oxygen Species Level

Andrographolide, a diterpenoid lactone and a major constituent of Andrographis paniculata Nees, exhibits remarkable anticancer activity. However, the effect of andrographolide on colon cancer has not been completely elucidated yet. Thus, we investigated the chemopreventive potential of andrographolide in colon cancer HT-29 cells. The cytotoxic potential of andrographolide on HT-29 cells was determined by MTT assay, trypan blue exclusion assay, colony formation assay, and morphological analysis; and apoptotic property by DAPI and Hoechst staining, FITC-Annexin V assay, DNA fragmentation assay and caspase-3 activity assay. To elucidate andrographolide action, intracellular reactive oxygen species (ROS) level was determined by DCFDA dye; change in mitochondrial potential by Rhodamine123 and Mito Tracker Red CMXRos dye; and cell cycle modulatory property by flow cytometric analysis. Results of the study have shown that andrographolide decreased cell viability of HT-29 cells in a dose- and time-dependent manner. Furthermore, andrographolide induced apoptosis in HT-29 cells which seemed to be linked with augmented intracellular ROS level and disruption of mitochondrial membrane potential. Interestingly, andrographolide caused significant cell cycle arrest in G2/M phase at lower doses, but, in G0/G1 phase at higher doses. In summary, our results indicated that andrographolide exhibited antiproliferative and apoptotic properties against colon cancer HT-29 cells.     

Ethanol extract of Innotus obliquus (Chaga mushroom) induces G1 cell cycle arrest in HT-29 human colon cancer cells

BACKGROUND/OBJECTIVES

Inonotus obliquus (I. obliquus, Chaga mushroom) has long been used as a folk medicine to treat cancer. In the present study, we examined whether or not ethanol extract of I. obliquus (EEIO) inhibits cell cycle progression in HT-29 human colon cancer cells, in addition to its mechanism of action.

MATERIALS/METHODS

To examine the effects of Inonotus obliquus on the cell cycle progression and the molecular mechanism in colon cancer cells, HT-29 human colon cancer cells were cultured in the presence of 2.5 - 10 µg/mL of EEIO, and analyzed the cell cycle arrest by flow cytometry and the cell cycle controlling protein expression by Western blotting.

RESULTS

Treatment cells with 2.5 - 10 µg/mL of EEIO reduced viable HT-29 cell numbers and DNA synthesis, increased the percentage of cells in G₁ phase, decreased protein expression of CDK2, CDK4, and cyclin D1, increased expression of p21, p27, and p53, and inhibited phosphorylation of Rb and E2F1 expression. Among I. obliquus fractions, fraction 2 (fractionated by dichloromethane from EEIO) showed the same effect as EEIO treatment on cell proliferation and cell cycle-related protein levels.

CONCLUSIONS

These results demonstrate that fraction 2 is the major fraction that induces G₁ arrest and inhibits cell proliferation, suggesting I. obliquus could be used as a natural anti-cancer ingredient in the food and/or pharmaceutical industry.     

Pomegranate ellagitannin-gut microbial-derived metabolites,urolithins, inhibit neuroinflammation in vitro

Objectives: Urolithins, ellagitannin-gut microbial-derived metabolites, have been reported to mediate pomegranate’s neuroprotective effects against Alzheimer’s disease (AD), but there are limited data on their effects against neuroinflammation. Herein, we: (1) evaluated whether urolithins (urolithins A and B and their methylated derivatives) attenuate neuroinflammation in murine BV-2 microglia and human SH-SY5Y neurons, and (2) evaluated hippocampus of transgenic AD (R1.40) mice administered a pomegranate extract (PE; 100 or 200?mg/kg/day for 3 weeks) for inflammatory biomarkers.

Methods: Effects of urolithins (10?μM) on inflammatory biomarkers were evaluated in lipopolysaccharide (LPS)-stimulated BV-2 microglia. In a non-contact co-culture cell model, SH-SY5Y cell viability was assessed after exposure to media collected from LPS-BV-2 cells treated with or without urolithins. Effects of urolithins on apoptosis and caspase 3/7 and 9 release from H₂O₂-induced oxidative stress of BV-2 and SH-SY5Y cells were assessed. Hippocampal tissues of vehicle and PE-treated transgenic R1.40 mice were evaluated for gene expression of inflammatory biomarkers by qRT-PCR.

Results: Urolithins decreased media levels of nitric oxide, interleukin 6 (IL-6), prostaglandin E₂, and tumor necrosis factor alpha from LPS-BV-2 microglia. In the co-culture cell model, media from LPS-BV-2 cells treated with urolithins preserved SH-SY5Y cell viability greater than media from cells treated without urolithins. Urolithins mitigated apoptosis and caspase 3/7 and 9 release from H₂O₂-induced oxidative stress of BV-2 and SH-SY5Y cells. While not statistically significant, inflammatory biomarkers (TNF-α, COX-2, IL-1, and IL-6) appeared to follow a decreasing trend in the hippocampus of high-dose PE-treated animals compared to controls.

Discussion: The attenuation of neuroinflammation by urolithins may contribute, in part, toward pomegranate’s neuroprotective effects against AD.     

Synthesis, antiproliferative activity, and mechanism of action of a series of 2-{[(2E)-3-phenylprop-2-enoyl]amino}benzamides

Several new 2-{[(2E)-3-phenylprop-2-enoyl]amino}benzamides 12a-s and 17t-v were synthesized by stirring in pyridine the (E)-3-(2-R1-3-R2-4-R3-phenyl)acrylic acid chlorides 11c-k and 11t-v with the appropriate anthranilamide derivatives 10a-c or the 5-iodoanthranilic acid 13. Some of the synthesized compounds were evaluated for their in vitro antiproliferative activity against the full NCI tumor cell line panel derived from nine clinically isolated cancer types (leukemia, non-small cell lung, colon, CNS, melanoma, ovarian, renal, prostate and breast). COMPARE analysis, effects on tubulin polymerization in cells and with purified tubulin, and effects on cell cycle distribution for 17t, the most active of the series, indicate that these new antiproliferative compounds act as antitubulin agents.     

Antidiabetic activity of isoquercetin in diabetic KK -Ay mice

Background

Protective effects of omega-3 fatty acids against cellular damages of high glucose were studied on retinal pigmented epithelial (RPE) cells.

Methods

Retinal epithelial cells were incubated with omega-3 marine oils rich in EPA and DHA and then with high glucose (25 mM) for 48 hours. Cellular responses were compared to normal glucose (5 mM): intracellular redox status, reactive oxygen species (ROS), mitochondrial succinate deshydrogenase activity, inflammatory cytokines release and caveolin-1 expression were evaluated using microplate cytometry, ELISA and flow cytometry techniques. Fatty acids incorporation in retinal cell membranes was analysed using chromatography.

Results

Preincubation of the cells with fish oil decreased ROS overproduction, mitochondrial alterations and TNFα release. These protective effects could be attributed to an increase in caveolin-1 expression induced by marine oil.

Conclusion

Marine formulations rich in omega-3 fatty acids represent a promising therapeutic approach for diabetic retinopathy.     

Chemopreventive effects of in vitro digested and fermented bread in human colon cells

Purpose

Bread as a staple food product represents an important source for dietary fibre consumption. Effects of wheat bread, wholemeal wheat bread and wholemeal rye bread on mechanisms which could have impact on chemoprevention were analysed in colon cells after in vitro fermentation.

Methods

Effects of fermented bread samples on gene expression, glutathione S-transferase activity and glutathione content, differentiation, growth and apoptosis were investigated using the human colon adenoma cell line LT97. Additionally, apoptosis was studied in normal and tumour colon tissue by determination of caspase activities.

Results

The expression of 76 genes (biotransformation, differentiation, apoptosis) was significantly upregulated (1.5-fold) in LT97 cells. The fermented bread samples were able to significantly increase glutathione S-transferase activity (1.8-fold) and glutathione content (1.4-fold) of the cells. Alkaline phosphatase activity as a marker of differentiation was also significantly enhanced (1.7-fold). The fermented bread samples significantly inhibited LT97 cell growth and increased the level of apoptotic cells (1.8-fold). Only marginal effects on apoptosis in tumour compared to normal tissue were observed.

Conclusions

This is the first study which presents chemopreventive effects of different breads after in vitro fermentation. In spite of differences in composition, the results were comparable between the bread types. Nevertheless, they indicate a potential involvement of this staple food product regarding the prevention of colon cancer.     

Effect of urolithins on oxidative stress of colorectal adenocarcinomacells-Caco-2

Urolithins (UROs) are metabolites derived from ellagic acid (EA) and ellagitannins (ETs) by gut microbiota after consumption of different ETs. The health effects attributed to UROs are numerous and diverse, ranging from antimalarial properties to anticancer activities and regulation of gene expression. The aim of this work was at assessing the effect of URO-A; -B; -C; -D on the oxidative status of colon epithelium using as a model colorectal adenocarcinoma cell line (Caco-2). No significant cytotoxic effects of UROs was noted, with the applied treatments. Supplementation of cell growth medium with a mixture of UROs decreased the level of intracellular reactive oxygen species both after short- and long-term exposure. UROs also affected the activity of antioxidative enzymes within the cell, especially catalase.

Conclusions: At concentrations reached in the lumen of the gut, UROs can exert beneficial effects on the cells by decreasing oxidative stress thus preventing the damage caused by reactive oxygen species.     

Körperliche Aktivität in der Freizeit Deutsche Herz-Kreislauf-Präventionsstudie (DHP): Ergebnisse der Regionalen Gesundheitssurveys 1984/5 - 1988 -1991/2 für die Region Stuttgart

Objective

To test the hypothesis that community-oriented intervention programmes can promote physical leisure time activity.

Design Cross-sectional community-based multicentre intervention study

Setting

Health surveys in 1984/5,1988 and 1991/2 in Stuttgart-West and Vaihingen

Subjects

25–69 year old population in the GCP-study-region of Stuttgart. Main outcome Measurement and comparison of prevalences and odds ratios

measures

of physical inactivity in 1984/5,1988, 1991/2.

Results

Physical activity decreased in all socioeconomic strata.

Conclusions

In spite of prevention leisure time physical activity declined in Stuttgart.     

Effects of adipocyte-secreted factors on cell cycle progression in HT29 cells

Background

Obesity is a chronic sub-inflammatory condition which is a risk factor for several cancer diseases, e.g. colon cancer. Adipose tissue secretes biologically active factors like leptin with a known pro-inflammatory or mitogenic activity. Both, chronic inflammation and an increased cell proliferation are considered to play an important role in colon carcinogenesis. Diverse phytochemicals were shown to have cell growth inhibiting effects.

Aim of the study

The aim was to investigate whether adipocytes could mediate a proliferative capacity to HT29, a human colon adenocarcinoma cell line, and whether phytochemicals could modulate this effect.

Methods

Infranatants of adipocyte cultures from different donors were prepared and the effects of those conditioned adipocyte media (CAM) on HT29 cell growth were measured. Additionally, cell cycle progression was analyzed by flow cytometry after CAM treatment and ERK 1/2 phosphorylation was analyzed.

Results

CAM from a subgroup of adipose tissue donors stimulated HT29 cell growth, whereas others did not. This effect seems to be mediated via the ERK 1/2 pathway. Furthermore, CAM caused changes in cell cycle distribution with a shift of HT29 cells from G1- into the S-phase. This effect could be mimicked by leptin (1 nM). Co-incubation of CAM-treated HT29 cultures with β-carotene or EGCG did not have a significant impact on cell cycle progression, whereas genistein (30 µM) tended to inhibit the CAM-stimulated transition of cells into the S-phase.

Conclusion

This study confirmed the mitogenic activity of leptin in HT29 cells, although leptin secretion from adipocytes is not likely to be responsible for CAM-stimulated cell growth in our test system. The investigated phytochemicals seem to have only a minor influence on CAM-mediated cell cycle progression.

     

Comparative Analysis of the Impact of Urolithins on the Composition of the Gut Microbiota in Normal-Diet Fed Rats

The gut microbiota consists of a community of microorganisms that inhabit the large intestine. These microbes play important roles in maintaining gut barrier integrity, inflammation, lipid and carbohydrate metabolism, immunity, and protection against pathogens. However, recent studies have shown that dysfunction in the gut microbiota composition can lead to the development of several diseases. Urolithin A has recently been approved as a functional food ingredient. In this study, we examined the potentials of urolithin A (Uro-A) and B (Uro-B) in improving metabolic functions and their impact on gut microbiota composition under a metabolically unchallenged state in normal rats. Male Wistar rats (n = 18) were randomly segregated into three groups, with Group 1 serving as the control group. Groups 2 and 3 were administered with 2.5 mg/kg Uro-A and Uro-B, respectively, for four weeks. Our results showed that both Uro-A and B improved liver and kidney functions without affecting body weight. Metagenomic analysis revealed that both Uro-A and B induced the growth of Akkermansia. However, Uro-A decreased species diversity and microbial richness and negatively impacted the composition of pathogenic microbes in normal rats. Taken together, this study showed the differential impacts of Uro-A and B on the gut microbiota composition in normal rats and would thus serve as a guide in the choice of these metabolites as a functional food ingredient or prebiotic.     

Health implications of fructose consumption: A review of recent data

Background

An increase in the intestinal permeability is considered to be associated with the inflammatory tone and development in the obesity and diabetes, however, the pathogenesis of the increase in the intestinal permeability is poorly understood. The present study was performed to determine the influence of obesity itself as well as dietary fat on the increase in intestinal permeability.

Methods

An obese rat strain, Otsuka Long Evans Tokushima Fatty (OLETF), and the lean counter strain, Long Evans Tokushima Otsuka (LETO), were fed standard or high fat diets for 16 weeks. Glucose tolerance, intestinal permeability, intestinal tight junction (TJ) proteins expression, plasma bile acids concentration were evaluated. In addition, the effects of rat bile juice and dietary fat, possible mediators of the increase in the intestinal permeability in the obesity, on TJ permeability were explored in human intestinal Caco-2 cells.

Results

The OLETF rats showed higher glucose intolerance than did the LETO rats, which became more marked with the prolonged feeding of the high fat diet. Intestinal permeability in the OLETF rats evaluated by the urinary excretion of intestinal permeability markers (Cr-EDTA and phenolsulfonphthalein) was comparable to that in the LETO rats. Feeding the high fat diet increased intestinal permeability in both the OLETF and LETO rats, and the increases correlated with decreases in TJ proteins (claudin-1, claudin-3, occludin and junctional adhesion molecule-1) expression in the small, but not in the large intestine (cecum or colon). The plasma bile acids concentration was higher in rats fed the high fat diet. Exposure to bile juice and the fat emulsion increased TJ permeability with concomitant reductions in TJ protein expression (claudin-1, claudin-3, and junctional adhesion molecule-1) in the Caco-2 cell monolayers.

Conclusion

Excessive dietary fat and/or increased levels of luminal bile juice, but not genetic obesity, are responsible for the increase in small intestinal permeability resulting from the suppression of TJ protein expression.     

Modified apple polysaccharide prevents against tumorigenesis in a mouse model of colitis-associated colon cancer: role of galectin-3 and apoptosis in cancer prevention

Background

Colorectal cancer (CRC) is one of the most common and preventable cancers. Regular consumption of apples is conducive to reduction in CRC risk.

Aim of the study

To evaluate effects of modified apple polysaccharide (MAP) on tumorigenesis in a mouse model of colitis-associated colon cancer.

Methods

One hundred male ICR mice were administered with 1, 2-dimethyl-hydrazine (DMH) and dextran sodium sulfate (DSS). Forty mice were given no further treatment, the rest were fed basal diet blended with three different doses of MAP; 2.5, 5, and 10% (20 mice in each group).

Results

MAP significantly protected ICR mice against DMH/DSS-induced tumorigenesis. The incidence of tumor development was 90% (18/20) in the mice treated with DMH/DSS, but that was reduced to 25% (5/20), 15% (3/20), and 5% (1/20), respectively, in the mice treated with basal diets plus 2.5, 5, and 10% of MAP. Study of apoptosis of colonic epithelial cells revealed that MAP moderately increased apoptosis, suggesting that the anti-tumor potency of MAP was probably attributed to its ability to induce apoptosis. Western blot analysis demonstrated that carbohydrate-binding protein galectin-3 changed in both the nucleus and the cytoplasm during the process from colitis to colon cancer in the model. And MAP could inhibit the binding of galectin-3 to its ligand: this is, at least in part, the possible mechanism of MAP by enhancing apoptosis and preventing tumorigenesis.

Conclusions

These data suggest that MAP has a potential role in clinical prevention and treatment for colon cancer.     

Oleic acid inhibits store-operated calcium entry in human colorectal adenocarcinoma cells

Aims

Much evidence indicates the association between dietary fat and colorectal cancer risk. However, most of the studies focus on polyunsaturated fatty acids, and little is known about the role of monounsaturated ones and their precise mechanism of action. Being store-operated Ca²⁺ entry (SOCE) a Ca²⁺ influx pathway involved in the control of multiple cellular and physiological processes including cell proliferation, we studied the effect of oleic acid in Ca²⁺ signals of colorectal cancer cells, paying particular attention to SOCE.

Methods

Carbachol was used to induce SOCE in Fura 2-loaded HT29 cells. We tested a saturated fatty acid to compare the physiological relevance of our results.

Results

We show that oleic acid is a potent inhibitor of SOCE. By contrast, stearic acid failed to have a SOCE-inhibitory effect. The SOCE-inhibition induced by oleic acid was protein kinase C-independent and restored by albumin. We also demonstrated that oleic acid induced increases in [Ca²⁺]_i. The novelty of our report is that little variability in the concentration could end in a large different physiological effect.

Conclusions

In conclusion, we suggest a physiological pathway for the beneficial effect of oleic acid in colon carcinoma cells.     

Functional relevance of d,l-sulforaphane-mediated induction of vimentin and plasminogen activator inhibitor-1 in human prostate cancer cells

Purpose

d,l-Sulforaphane (SFN) is a promising chemopreventive agent with in vivo efficacy against prostate cancer in experimental rodents. This study was undertaken to determine the role of vimentin and plasminogen activator inhibitor-1 (PAI-1) in anticancer effects of SFN.

Methods

Effect of SFN on levels of different proteins was determined by Western blotting or immunofluorescence microscopy. RNA interference of vimentin and PAI-1 was achieved by transient transfection. Apoptosis was quantified by flow cytometry. Transwell chambers were used to determine cell migration.

Results

Exposure of PC-3 and DU145 human prostate cancer cells to SFN resulted in induction of vimentin protein, which was accompanied by down-regulation of E-cadherin protein expression. The SFN-mediated induction of vimentin was also observed in a normal human prostate epithelial cell line. RNA interference of vimentin did not have any appreciable effect on early or late apoptosis resulting from SFN exposure. On the other hand, SFN-mediated inhibition of PC-3 and DU145 cell migration was significantly augmented by knockdown of the vimentin protein. Knockdown of vimentin itself was inhibitory against cell migration. The SFN-treated cells also exhibited induction of PAI-1, which is an endogenous inhibitor of urokinase-type plasminogen activator system. Similar to vimentin, PAI-1 knockdown resulted in a modest augmentation of PC-3 cell migration inhibition by SFN. Tumors from SFN-treated transgenic adenocarcinoma of mouse prostate mice showed a 1.7-fold increase in vimentin protein level compared with control tumors.

Conclusion

The present study indicates that vimentin and PAI-1 inductions confer modest protection against SFN-mediated inhibition of prostate cancer cell migration.     

Differential alterations of the concentrations of endocannabinoids and related lipids in the subcutaneous adipose tissue of obese diabetic patients

Background

Statins induces cell cycle arrest, apoptosis, reduction of angiogenic factors, inhibition of the endothelial growth factor, impairing tissue adhesion and attenuation of the resistance mechanisms. The aim of this study was evaluate the anti-tumoral activity of simvastatin in a B16F10 melanoma-mouse model.

Methods

Melanoma cells were treated with different concentrations of simvastatin and assessed by viability methods. Melanoma cells (5 × 10⁴) were implanted in two month old C57Bl6/J mice. Around 7 days after cells injection, the oral treatments were started with simvastatin (5 mg/kg/day, p.o.). Tumor size, hematological and biochemical analyses were evaluated.

Results

Simvastatin at a concentration of 0.8 μM, 1.2 μM and 1.6 μM had toxic effect. Concentration of 1.6 μM induced a massive death in the first 24 h of incubation. Simvastatin at 0.8 μM induces early cell cycle arrest in G0/G1, followed by increase of hypodiploidy. Tumor size were evaluated and the difference of treated group and control, after ten days, demonstrates that simvastatin inhibited the tumor expansion in 68%.

Conclusion

Simvastatin at 1.6 μM, presented cytototoxicity after 72 h of treatment, with an intense death. In vivo, simvastatin being potentially useful as an antiproliferative drug, with an impairment of growth after ten days.     

Avenanthramides Inhibit Proliferation of Human Colon Cancer Cell Lines In Vitro

A high intake of whole grain foods is associated with reduced risk of colon cancer, but the mechanism underlying this protection has yet to be elucidated. Chronic inflammation and associated cyclooxygenase-2 (COX-2) expression in the colon epithelium are causally related to epithelial carcinogenesis, proliferation, and tumor growth. We examined the effect of avenanthramides (Avns), unique polyphenols from oats with anti-inflammatory properties, on COX-2 expression in macrophages, colon cancer cell lines, and on proliferation of human colon cancer cell lines. We found that Avns-enriched extract of oats (AvExO) had no effect on COX-2 expression, but it did inhibit COX enzyme activity and prostaglandin E₂ (PGE₂) production in lipopolysaccharide-stimulated mouse peritoneal macrophages. Avns (AvExO, Avn-C, and the methylated form of Avn-C (CH3-Avn-C)) significantly inhibited cell proliferation of both COX-2-positive HT29, Caco-2, and LS174T, and COX-2-negative HCT116 human colon cancer cell lines, CH3-Avn-C being the most potent. However, Avns had no effect on COX-2 expression and PGE₂ production in Caco-2 and HT29 colon cancer cells. These results indicate that the inhibitory effect of Avns on colon cancer cell proliferation may be independent of COX-2 expression and PGE₂ production. Thus, Avns might reduce colon cancer risk through inhibition of macrophage PGE₂ production and non-COX-related antiproliferative effects in colon cancer cells. Interestingly, Avns had no effect on cell viability of confluence-induced differentiated Caco-2 cells, which display the characteristics of normal colonic epithelial cells. Our results suggest that the consumption of oats and oat bran may reduce the risk of colon cancer not only because of their high fiber content but also due to Avns, which attenuate proliferation of colonic cancer cells.