S-adenosyl L-methionine inhibits azoxymethane-induced colonic aberrant crypt foci in F344 rats and suppresses human colon cancer Caco-2 cell growth in 3D culture

Effect of S-adenosyl-methionine accumulation on hineka odor in sake brewed with a non-Kyokai yeast

Hineka is a type of off-flavor of sake and is attributed to the presence of several compounds, including a major one called dimethyl trisulfide (DMTS). The production of the main precursor of DMTS involves yeast methionine salvage pathway. The DMTS-producing potential (DMTS-pp) of sake brewed using the Km67 strain, a non-Kyokai sake yeast, is lower than that of sake brewed using Kyokai yeast; however, the detailed mechanism is unclear. We focused on S-adenosyl-methionine (SAM) and aimed to elucidate the mechanism that prevents DMTS production in sake brewed using the Km67 strain. We revealed that SAM is involved in DMTS production in sake, and that the conversion of SAM to the DMTS precursor occurs through an enzymatic reaction rather than a chemical reaction. Based on previous reports on ADO1 and MDE1 genes, sake brewing tests were performed using the Km67 Δmde1, Δado1, and Δmde1Δado1 strains. A comparison of the SAM content of pressed sake cakes and DMTS-pp of sake produced using the Km67 Δado1 strain showed an increase in both SAM content and DMTS-pp compared to those produced using the parent strain. However, the Km67 Δmde1Δado1 strain showed little increase in DMTS-pp compared to the Km67 Δmde1 strain, despite an increase in SAM content. These results suggest that SAM accumulation in yeast plays a role in the production of DMTS in sake through the methionine salvage pathway. Moreover, the low SAM-accumulation characteristic of the Km67 strain contributes to low DMTS production in sake.

Targeting pathophysiological changes using biomaterials-based drug delivery systems: A key to managing inflammatory bowel disease

Inflammatory bowel disease (IBD) is a gastrointestinal disorder, affecting about several million people worldwide. Current treatments fail to adequately control some clinical symptoms in IBD patients, which can adversely impact the patient's quality of life. Hence, the development of new treatments for IBD is needed. Due to their unique properties such as biocompatibility and sustained release of a drug, biomaterials-based drug delivery systems can be regarded as promising candidates for IBD treatment. It is noteworthy that considering the pathophysiological changes occurred in the gastrointestinal tract of IBD patients, especially changes in pH, surface charge, the concentration of reactive oxygen species, and the expression of some biomolecules at the inflamed colon, can help in the rational design of biomaterials-based drug delivery systems for efficient management of IBD. Here, we discuss about targeting these pathophysiological changes using biomaterials-based drug delivery systems, which can provide important clues to establish a strategic roadmap for future studies.

Gastrointestinal Cancer Patient Nutritional Management: From Specific Needs to Novel Epigenetic Dietary Approaches

Nutritional habits impinge on the health of the gastrointestinal (GI) tract, contributing to GI disorder progression. GI cancer is a widespread and aggressive tumor sensitive to nutritional changes. Indeed, specific nutritional expedients can be adopted to prevent GI cancer onset and to slow down disease activity. Moreover, the patient’s nutritional status impacts prognosis, quality of life, and chemotherapy tolerance. These patients encounter the highest frequency of malnourishment risk, a condition that can progressively evolve into cachexia. Clinical studies dealing with this topic stressed the importance of nutritional counseling and put under the spotlight nutrient delivery, the type of nutrient supplementation, and timing for the start of nutritional management. A medical practitioner well-prepared on the topic of nutrition and cancer should operate in the clinical team dedicated to these oncological patients. This specific expertise needs to be implemented as soon as possible to adopt nutritional interventions and establish a proper patient-tailored dietary regimen. The nutritional gap closure should be prompt during anticancer treatment to stabilize weight loss, improve treatment tolerability, and ameliorate survival rate. Recently, novel nutritional approaches were investigated to target the bidirectional link between epigenetics and metabolism, whose alteration supports the onset, progression, and therapeutic response of GI cancer patients.

Cost-Effective Production of ATP and S-Adenosylmethionine Using Engineered Multidomain Scaffold Proteins

Adenosine triphosphate (ATP) and S-adenosyl-L-methionine (SAM) are important intermediates that are widely present in living organisms. Large-scale preparation and application of ATP or SAM is limited by expensive raw materials. To lower the production costs for ATP/SAM, in this study we used strategies applying engineered multidomain scaffold proteins to synthesize ATP and SAM. An artificial scaffold protein containing CBM3 domain, IM proteins and CL-labeled proteins was assembled to form complex 1 for catalytic reactions to increase ATP production. The ATP synthesis system produced approximately 25 g/L of ATP with approximately 15 g/L of ADP and 5 g/L of AMP using 12.5 g/L of adenosine and 40 g/L of sodium hexametaphosphate reaction at 35 °C and a pH of 8.5 for 6 h. Based on the above ATP synthesis system, two CL-labeled methionine adenosyltransferases (CL9-MAT4 and CL9-MAT5) were applied to construct scaffold protein complex 2 to achieve SAM synthesis. Approximately 25 μg of MAT4 in a reaction system with 0.3 M MgCl2 catalyzed at 20 °C and a pH of 8 catalyzed 0.5 g/L of l-Met to produce approximately 0.9 g/L of SAM. Approximately 25 μg of MAT5 in a reaction system with 0.7 M MgCl2 catalyzed at 35 °C and a pH of 8 catalyzed 0.5 g/L of l-Met to produce approximately 1.2 g/L of SAM. Here, we showed that low-cost substrates can be efficiently converted into high-value additional ATP and SAM via multi-enzyme catalytic reactions by engineered multidomain scaffold proteins.

Interplay between Epigenetics and Cellular Metabolism in Colorectal Cancer

Cellular metabolism alterations have been recognized as one of the most predominant hallmarks of colorectal cancers (CRCs). It is precisely regulated by many oncogenic signaling pathways in all kinds of regulatory levels, including transcriptional, post-transcriptional, translational and post-translational levels. Among these regulatory factors, epigenetics play an essential role in the modulation of cellular metabolism. On the one hand, epigenetics can regulate cellular metabolism via directly controlling the transcription of genes encoding metabolic enzymes of transporters. On the other hand, epigenetics can regulate major transcriptional factors and signaling pathways that control the transcription of genes encoding metabolic enzymes or transporters, or affecting the translation, activation, stabilization, or translocation of metabolic enzymes or transporters. Interestingly, epigenetics can also be controlled by cellular metabolism. Metabolites not only directly influence epigenetic processes, but also affect the activity of epigenetic enzymes. Actually, both cellular metabolism pathways and epigenetic processes are controlled by enzymes. They are highly intertwined and are essential for oncogenesis and tumor development of CRCs. Therefore, they are potential therapeutic targets for the treatment of CRCs. In recent years, both epigenetic and metabolism inhibitors are studied for clinical use to treat CRCs. In this review, we depict the interplay between epigenetics and cellular metabolism in CRCs and summarize the underlying molecular mechanisms and their potential applications for clinical therapy.

S-Adenosylmethionine Treatment of Colorectal Cancer Cell Lines Alters DNA Methylation, DNA Repair and Tumor Progression-Related Gene Expression

Global DNA hypomethylation is a characteristic feature of colorectal carcinoma (CRC). The tumor inhibitory effect of S-adenosylmethionine (SAM) methyl donor has been described in certain cancers including CRC. However, the molecular impact of SAM treatment on CRC cell lines with distinct genetic features has not been evaluated comprehensively. HT-29 and SW480 cells were treated with 0.5 and 1 mmol/L SAM for 48 h followed by cell proliferation measurements, whole-genome transcriptome and methylome analyses, DNA stability assessments and exome sequencing. SAM reduced cell number and increased senescence by causing S phase arrest, besides, multiple EMT-related genes (e.g., TGFB1) were downregulated in both cell lines. Alteration in the global DNA methylation level was not observed, but certain methylation changes in gene promoters were detected. SAM-induced γ-H2AX elevation could be associated with activated DNA repair pathway showing upregulated gene expression (e.g., HUS1). Remarkable genomic stability elevation, namely, decreased micronucleus number and comet tail length was observed only in SW480 after treatment. SAM has the potential to induce senescence, DNA repair, genome stability and to reduce CRC progression. However, the different therapeutic responses of HT-29 and SW480 to SAM emphasize the importance of the molecular characterization of CRC cases prior to methyl donor supplementation.

Djulis (Chenopodium Formosanum) Prevents Colon Carcinogenesis via Regulating Antioxidative and Apoptotic Pathways in Rats

Djulis is a cereal crop rich in polyphenols and dietary fiber that may have nutraceutical activity to prevent colon cancer. This study was designed to examine the preventive effect of djulis on colon carcinogenesis in rats treated with 1,2-dimethylhydrazine (DMH). Rats were fed different AIN-93G-based diets: groups N and DMH were fed AIN-93G diet and groups LD, MD, and HD were fed AIN-93G diet containing 5, 10, and 20% djulis, respectively. All rats except for group N were injected with DMH to induce colon carcinogenesis. After 10 weeks, rats were sacrificed and colon and liver tissues were collected for analysis. The results showed that djulis-treated rats had significantly lower numbers of colonic preneoplastic lesions, aberrant crypt foci (ACF), sialomucin-producing (SIM)-ACF, and mucin-depleted foci. Djulis treatment increased superoxide dismutase and catalase activities in colon and liver. Djulis also reduced p53, Bcl-2, and proliferating cell nuclear antigen expressions and increased Bax and caspase-9 expressions. Besides, phenolic compounds and flavonoids were found rich in djulis. These results demonstrate the chemopreventive effect of djulis on carcinogen-induced colon carcinogenesis via regulating antioxidative and apoptotic pathways in rats. Djulis may have the potential to be developed as a valuable cereal product for chemoprevention of colon cancer.

Metabolic engineering of Bacillus amyloliquefaciens for enhanced production of S-adenosylmethionine by coupling of an engineered S-adenosylmethionine pathway and the tricarboxylic acid cycle

BACKGROUND

S-Adenosylmethionine (SAM) is a critical cofactor involved in many biochemical reactions. However, the low fermentation titer of SAM in methionine-free medium hampers commercial-scale production. The SAM synthesis pathway is specially related to the tricarboxylic acid (TCA) cycle in Bacillus amyloliquefaciens. Therefore, the SAM synthesis pathway was engineered and coupled with the TCA cycle in B. amyloliquefaciens to improve SAM production in methionine-free medium.

RESULTS

Four genes were found to significantly affect SAM production, including SAM2 from Saccharomyces cerevisiae, metA and metB from Escherichia coli, and native mccA. These four genes were combined to engineer the SAM pathway, resulting in a 1.42-fold increase in SAM titer using recombinant strain HSAM1. The engineered SAM pathway was subsequently coupled with the TCA cycle through deletion of succinyl-CoA synthetase gene sucC, and the resulted HSAM2 mutant produced a maximum SAM titer of 107.47 mg/L, representing a 0.59-fold increase over HSAM1. Expression of SAM2 in this strain via a recombinant plasmid resulted in strain HSAM3 that produced 648.99 mg/L SAM following semi-continuous flask batch fermentation, a much higher yield than previously reported for methionine-free medium.

CONCLUSIONS

This study reports an efficient strategy for improving SAM production that can also be applied for generation of SAM cofactors supporting group transfer reactions, which could benefit metabolic engineering, chemical biology and synthetic biology.

The dual role of N6-methyladenosine modification of RNAs is involved in human cancers

As the most abundant and reversible RNA modification in eukaryotic cells, m⁶A triggers a new layer of epi‐transcription. M⁶A modification occurs through a methylation process modified by “writers” complexes, reversed by “erasers”, and exerts its role depending on various “readers”. Emerging evidence shows that there is a strong association between m⁶A and human diseases, especially cancers. Herein, we review bi‐aspects of m⁶A in regulating cancers mediated by the m⁶A‐associated proteins, which exert vital and specific roles in the development of various cancers. Generally, the m⁶A modification performs promotion or inhibition functions (dual role) in tumorigenesis and progression of various cancers, which suggests a new concept in cancer regulations. In addition, m⁶A‐targeted therapies including competitive antagonists of m⁶A‐associated proteins may provide a new tumour intervention in the future.

Immunohistochemical, histopathological study and chemoprotective effect of Solanum nigrum in N-nitrosodiethylamine-induced hepatocellular carcinoma in Wistar rats

Background and Aim

Cancer is a devastating disease with a severe impact on the physical and psychological well-being of patients. Hepatocellular carcinoma (HCC) has been reported in various species of animals including dogs, cats, sheep, and pigs. The present study aimed to study the immunohistochemical and histopathological changes andchemoprotective effect of aqueous and alcoholic extracts of Solanum nigrum on N-nitrosodiethylamine (NDEA)-induced HCC rat model.

Materials and Methods

Eighty-two male Wistar rats of 15 weeks of age weighing 200-250 g were selected for the experiment. They were randomly divided into ten groups. Group I served as normal control consisted of healthy rats. HCC was induced in Group II, IV, V, VI, VII, and X rats using NDEA as inducing agent followed by phenobarbitone as a promoter for 16 weeks. Group II rats were kept untreated as HCC control. Group III rats were kept as vehicle control (0.05% Sodium bicarbonate). Group IV and V rats were treated with aqueous extract of S. nigrum at 200 mg/kg and 400 mg/kg, respectively, and Group VI and VII rats were treated with an alcoholic extract of S. nigrum at 200 mg/kg and 400 mg/kg, respectively, daily orally for 28 days. Group X rats were treated withsorafenib as reference drug at a dose of 11.4 mg/kg daily orally for 28 days. Group VIII and IX rats were kept as aqueous and alcoholic extract control for studying the effect of the same on normal rats. Liver samples were collected to study the gross and histopathological lesions and the activity of cleaved caspase-3 and chemopreventive effect of aqueous and alcoholic extracts of S. nigrum on HCC.

Results

The liver sections of rats from HCC control (Group II) showed loss of lobular architecture, necrosis, fatty change, enlarged and darkened nuclei with variable size, dilatation of hepatic sinusoids with Kupffer cell hyperplasia, dilatation and proliferation of bile duct, and intranuclear vacuoles and also showed the presence of more than one nucleolus. Administration of alcoholic extract of S. nigrum and sorafenib to NDEA/phenobarbital-treated rats reduced the severity of lesions in the liver. Immunohistochemical analysis of liver sections for caspase-3-positive cells of hepatic cancer-induced group showed immunoreactivity to rarely few. The immunoreactivity of the hepatocytes treated with a higher dose of alcoholic extract of S. nigrum was limited and was comparable to a standard drug, sorafenib.

Conclusion

Oral administration of aqueous and alcoholic extracts of S. nigrum for 28 days showed significant rejuvenation in the structure of the liver in the histopathological section in a dose-dependent manner in rats.

Multiple functions of m6A RNA methylation in cancer

First identified in 1974, m⁶A RNA methylation, which serves as a predominant internal modification of RNA in higher eukaryotes, has gained prodigious interest in recent years. Modifications of m⁶A are dynamic and reversible in mammalian cells, which have been proposed as another layer of epigenetic regulation similar to DNA and histone modifications. m⁶A RNA methylation is involved in all stages in the life cycle of RNA, ranging from RNA processing, through nuclear export, translation modulation to RNA degradation, which suggests its potential of influencing a plurality of aspects of RNA metabolism. All of the recent studies have pointed to a complicated regulation network of m⁶A modification in different tissues, cell lines, and space–time models. m⁶A methylation has been found to have an impact on tumor initiation and progression through various mechanisms. Furthermore, m⁶A RNA methylation has provided new opportunities for early stage diagnosis and treatment of cancers.

Herein, we review the chemical basis of m⁶A RNA methylation, its multiple functions and potential significance in cancer.

m6A RNA Methylation Regulates the Self-Renewal and Tumorigenesis of Glioblastoma Stem Cells

RNA modifications play critical roles in important biological processes. However, the functions of N⁶-methyladenosine (m⁶A) mRNA modification in cancer biology and cancer stem cells remain largely unknown. Here, we show that m⁶A mRNA modification is critical for glioblastoma stem cell (GSC) self-renewal and tumorigenesis. Knockdown of METTL3 or METTL14, key components of the RNA methyltransferase complex, dramatically promotes human GSC growth, self-renewal, and tumorigenesis. In contrast, overexpression of METTL3 or inhibition of the RNA demethylase FTO suppresses GSC growth and self-renewal. Moreover, inhibition of FTO suppresses tumor progression and prolongs lifespan of GSC-grafted mice substantially. m⁶A sequencing reveals that knockdown of METTL3 or METTL14 induced changes in mRNA m⁶A enrichment and altered mRNA expression of genes (e.g., ADAM19) with critical biological functions in GSCs. In summary, this study identifies the m⁶A mRNA methylation machinery as promising therapeutic targets for glioblastoma.

The third dimension: new developments in cell culture models for colorectal research

Cellular models are important tools in various research areas related to colorectal biology and associated diseases. Herein, we review the most widely used cell lines and the different techniques to grow them, either as cell monolayer, polarized two-dimensional epithelia on membrane filters, or as three-dimensional spheres in scaffold-free or matrix-supported culture conditions. Moreover, recent developments, such as gut-on-chip devices or the ex vivo growth of biopsy-derived organoids, are also discussed. We provide an overview on the potential applications but also on the limitations for each of these techniques, while evaluating their contribution to provide more reliable cellular models for research, diagnostic testing, or pharmacological validation related to colon physiology and pathophysiology.

N6-methyladenosine modification in mRNA: machinery, function and implications for health and diseases

N6-methyladenosine (m(6) A) modification in mRNA is extremely widespread, and functionally modulates the eukaryotic transcriptome to influence mRNA splicing, export, localization, translation, and stability. Methylated adenines are present in a large subset of mRNAs and long noncoding RNAs (lncRNAs). Methylation is reversible, and this is accomplished by the orchestrated action of highly conserved methyltransferase (m(6) A writer) and demethylase (m(6) A eraser) enzymes to shape the cellular 'epitranscriptome'. The engraved 'methyl code' is subsequently decoded and executed by a group of m(6) A reader/effector components, which, in turn, govern the fate of the modified transcripts, thereby dictating their potential for translation. Reversible mRNA methylation thus adds another layer of regulation at the post-transcriptional level in the gene expression programme of eukaryotes that finely sculpts a highly dynamic proteome in order to respond to diverse cues during cellular differentiation, immune tolerance, and neuronal signalling.

Evaporation-based microfluidic production of oil-free cell-containing hydrogel particles

We demonstrate an evaporation-based microfluidic strategy to produce oil-free cell containing hydrogel particles. Perfluoro-n-pentane, which is used as the continuous oil phase to generate cell-containing hydrogel (Extracel) particles, is removed at an elevated temperature. Human colon cancer cells (HCT116) encapsulated in the hydrogel particles show higher viability than cells encapsulated in particles that are produced via a non-evaporative oil phase. In addition, single HCT116 cells can be cultured for a week in such particles and respond to inflammatory stimuli, highlighting the potential applications of the developed strategy for 3D cell culture, drug testing, and cell-based drug delivery.

Regulatory T cells in cancer: an overview and perspectives on cyclooxygenase-2 and Foxp3 DNA methylation

Epigenetics has been gaining great attention as a therapeutic target in cancer. The cancer genome usually contains both hyper- and hypo-methylated genes to increase invasion, proliferation and metastasis. These cells not only operate their own growth, but also develop various strategies to escape from immune surveillance, and for this aim, regulatory T (Treg) cells support the cancer-mediated immune suppression. The fate of Treg cells is mainly controlled by DNA methylation within the promoter and intronic regions of Foxp3 gene. Foxp3 transcription factor is involved in the development, differentiation and function of Treg cells. COX-2 is also an epigenetically controlled gene in these processes. This enzyme and its product PGE2 plays essential roles in Treg functionality in cancer. Here, we discuss the effects of DNA methylation on cancer and nTreg cells. We also summarize the mechanisms related with COX-2/PGE2 and Foxp3 on inhibitory function of Treg cells in cancer.

Formulation of the Total Western Diet (TWD) as a basal diet for rodent cancer studies

Rodent cancer studies typically use defined diets with nutrient profiles optimized for rodent health. However, a defined rodent diet that represents typical American nutrition in all aspects, including calorie sources and macro- and micronutrient composition, is not yet available. Thus, a nutrient density approach was used to formulate the new Total Western Diet (TWD) based on NHANES data for macro- and micronutrient intakes. The TWD has fewer calories from protein and carbohydrate sources and twice that from fat as compared to the AIN-93 diet. The new diet contains more saturated and monounsaturated fats, less polyunsaturated fat, fewer complex carbohydrates, and twice the level of simple sugars. The TWD includes less calcium, copper, folate, thiamin, and vitamins B6, B12, D, and E, but much more sodium. This newly devised diet that better represents typical American nutrition will be highly useful for studies employing animal models of human disease, including cancer.

Rescue of glandular dysmorphogenesis in PTEN-deficient colorectal cancer epithelium by PPARγ-targeted therapy

Disruption of glandular architecture associates with poor clinical outcome in high-grade colorectal cancer (CRC). Phosphatase and tensin homolog deleted on chromosome ten (PTEN) regulates morphogenic growth of benign MDCK (Madin Darby Canine Kidney) cells through effects on the Rho-like GTPase cdc42 (cell division cycle 42). This study investigates PTEN-dependent morphogenesis in a CRC model. Stable short hairpin RNA knockdown of PTEN in Caco-2 cells influenced expression or localization of cdc42 guanine nucleotide exchange factors and inhibited cdc42 activation. Parental Caco-2 cells formed regular hollow gland-like structures (glands) with a single central lumen, in three-dimensional (3D) cultures. Conversely, PTEN-deficient Caco-2 ShPTEN cells formed irregular glands with multiple abnormal lumens as well as intra- and/or intercellular vacuoles evocative of the high-grade CRC phenotype. Effects of targeted treatment were investigated. Phosphatidinylinositol 3-kinase (PI3K) modulating treatment did not affect gland morphogenesis but did influence gland number, gland size and/or cell size within glands. As PTEN may be regulated by the nuclear receptor peroxisome proliferator-activated receptor-γ (PPARγ), cultures were treated with the PPARγ ligand rosiglitazone. This treatment enhanced PTEN expression, cdc42 activation and rescued dysmorphogenesis by restoring single lumen formation in Caco-2 ShPTEN glands. Rosiglitazone effects on cdc42 activation and Caco-2 ShPTEN gland development were attenuated by cotreatment with GW9662, a PPARγ antagonist. Taken together, these studies show PTEN-cdc42 regulation of lumen formation in a 3D model of human CRC glandular morphogenesis. Treatment by the PPARγ ligand rosiglitazone, but not PI3K modulators, rescued colorectal glandular dysmorphogenesis of PTEN deficiency.

Genistein, a soya isoflavone, prevents azoxymethane-induced up-regulation of WNT/β-catenin signalling and reduces colon pre-neoplasia in rats

The present study aimed to explore the role(s) of the soya isoflavone genistein (GEN) in preventing the development of colon pre-neoplasia, using Wingless/int (WNT)/β-catenin as a molecular marker of colon abnormality. Specifically, the effects on the WNT/β-catenin signalling pathway from GEN were examined by using an azoxymethane (AOM)-induced rat colon cancer model. Male Sprague-Dawley rats were fed a control (CTL), a soya protein isolate (SPI) or a GEN diet from gestation to 13 weeks of age. The first sampling was conducted at 7 weeks of age for pre-AOM analysis. The remaining rats were injected with AOM at 7 weeks of age. The descending colon was collected 6 weeks later for the evaluation of aberrant crypt foci (ACF), gene expression and nuclear protein accumulation. AOM injection induced aberrant nuclear accumulation of β-catenin in the CTL group but not in the SPI or GEN group. Moreover, the WNT target genes Cyclin D1 and c-Myc were repressed by SPI and GEN. Meanwhile, SPI and GEN suppressed the expression of WNT signalling genes including Wnt5a, Sfrp1, Sfrp2 and Sfrp5 to the similar level to that of the pre-AOM period. Rats fed SPI and GEN had a decreased number of total aberrant crypts. GEN feeding also resulted in a reduced number of ACF with N = 3 per foci. The reduction of WNT/β-catenin signalling was correlated with the decrease in total aberrant crypts. By testing WNT/β-catenin signalling as a biomarker of colon carcinogenic potential, we showed the novel role of GEN as a suppressor of carcinogen-induced WNT/β-catenin signalling in preventing the development of early colon neoplasia.

Advances in clinical application of S-adenosyl-L-methionine

The liver is an important metabolic and detoxification organ. As liver cells are extremely vulnerable to chemical substances, accumulation of metabolites, and viral infection, liver cell injury, which may induce cirrhosis and liver cancer, is often caused. S-adenosyl-L-methionine (SAMe), a natural substance present in various organisms, plays an important role in the regeneration and differentiation of liver cells and in regulating the sensitivity of liver cells to various types of injuries. Previously, SAMe had been widely used in the treatment of cholestatic liver disease. Recent studies have shown that SAMe as a methyl donor, can induce gene hypermethylation and reverse the overall low methylation, inhibit oncogene expression, reduce tumor invasiveness, and slow tumor metastasis. These findings open up new applications for SAMe in cancer prevention and treatment.

Dietary-feeding of grape seed extract prevents azoxymethane-induced colonic aberrant crypt foci formation in fischer 344 rats

Chemoprevention by dietary agents/supplements has emerged as a novel approach to control various malignancies, including colorectal cancer (CRC). This study assessed dietary grape seed extract (GSE) effectiveness in preventing azoxymethane (AOM)-induced aberrant crypt foci (ACF) formation and associated mechanisms in Fischer 344 rats. Six-week-old rats were injected with AOM, and fed control diet or the one supplemented with 0.25% or 0.5% (w/w) GSE in pre- and post-AOM or only post-AOM experimental protocols. At 16 wk of age, rats were sacrificed and colons were evaluated for ACF formation followed by cell proliferation, apoptosis, and molecular analyses by immunohistochemistry. GSE-feeding caused strong chemopreventive efficacy against AOM-induced ACF formation in terms of up to 60% (P < 0.001) reduction in number of ACF and 66% (P < 0.001) reduction in crypt multiplicity. Mechanistic studies showed that GSE-feeding inhibited AOM-induced cell proliferation but enhanced apoptosis in colon including ACF, together with a strong decrease in cyclin D1, COX-2, iNOS, and survivin levels. Additional studies showed that GSE-feeding also decreased AOM-caused increase in beta-catenin and NF-kappaB levels in colon tissues. Compared to control animals, GSE alone treatment did not show any considerable change in these biological and molecular events in colon, and was nontoxic. Together, these findings show the chemopreventive efficacy of GSE against the early steps of colon carcinogenesis in rats via likely targeting of beta-catenin and NF-kappaB signaling, and suggest its potential usefulness for the prevention of human CRC.

Cdc42 controls spindle orientation to position the apical surface during epithelial morphogenesis

The establishment of apical–basal polarity within a single cell and throughout a growing tissue is a key feature of epithelial morphogenesis. To examine the underlying mechanisms, the human intestinal epithelial cell line Caco-2 was grown in a three-dimensional matrix to generate a cystlike structure, where the apical surface of each epithelial cell faces a fluid-filled central lumen. A discrete apical domain is established as early as the first cell division and between the two daughter cells. During subsequent cell divisions, the apical domain of each daughter cell is maintained at the center of the growing structure through a combination of mitotic spindle orientation and asymmetric abscission. Depletion of Cdc42 does not prevent the establishment of apical–basal polarity in individual cells but rather disrupts spindle orientation, leading to inappropriate positioning of apical surfaces within the cyst. We conclude that Cdc42 regulates epithelial tissue morphogenesis by controlling spindle orientation during cell division.

Use of a novel genetic mouse model to investigate the role of folate in colitis-associated colon cancer

Inflammatory bowel disease (IBD) patients are at high risk for developing folate deficiency and colon cancer. Since it is difficult to study the subtle global and gene-specific epigenetic mechanisms involved in folate-mediated tumor initiation and promotion, we have generated genetically modified mouse models by targeting the reduced folate carrier (RFC1) and folate-binding protein (Folbp1) genes. The transgenic mice were fed semi-purified diets for 8 weeks containing either normal (2 mg) or deficient (0.1 mg folate/kg diet) levels of folate. Compound heterozygous mice (Folbp1(+/-); RFC1(+/-)) fed an adequate folate diet exhibited a reduction in plasma folate concentrations compared to heterozygous (Folbp1(+/-)) and littermate wild-type mice (P<.05). In contrast, no differences were observed in colonic mucosa. Consumption of a low folate diet significantly reduced (three- to fourfold) plasma and tissue folate levels in all animal models, although plasma homocysteine levels were not altered. In order to elucidate the relationship between folate status and inflammation-associated colon cancer, animals were injected with azoxymethane followed by dextran sodium sulphate treatment in the drinking water. Mice were fed a normal folate diet and were terminated 5 weeks after carcinogen injection. The number of high multiplicity aberrant crypt foci per centimeter of colon was significantly elevated (P<.05) in compound Folbp1(+/-); RFC1(+/-) (3.5+/-0.4) mice as compared to Folbp1(+/-) (1.9+/-0.3) and wild-type control mice (1.1+/-0.1). These data demonstrate that the ablation of two receptor/carrier-mediated pathways for folate transport increases the risk for developing inflammation-associated colon cancer.

Dietary manipulation of histone structure and function

Post-translational modifications of histones are the subject of intensive investigations with the aim of decoding how they regulate, alone or in combination, chromatin structure, genomic stability, and gene expression. Major epigenetic programming events take place during gametogenesis and fetal development and are thought to have long-lasting consequences on adult health. Epidemiological and experimental studies have pointed toward maternal nutrition as a major player during prenatal development in influencing disease susceptibility later in life. Although the mechanisms underlying such observations are not well elucidated, epigenetic alterations of histones by particular maternal diets might be of central importance. Moreover, as much as dietary sources can influence epigenetic programming during pregnancy, they have started to be implicated in cancer chemoprevention, via the targeting of reversible epigenetic deregulations at the level of the histones.