Dietary cocoa inhibits colitis associated cancer: a crucial involvement of the IL-6/STAT3 pathway

Intestinal metabolites in colitis-associated carcinogenesis: Building a bridge between host and microbiome

ABSTRACT

Microbial-derived metabolites are important mediators of host-microbial interactions. In recent years, the role of intestinal microbial metabolites in colorectal cancer has attracted considerable attention. These metabolites, which can be derived from bacterial metabolism of dietary substrates, modification of host molecules such as bile acids, or directly from bacteria, strongly influence the progression of colitis-associated cancer (CAC) by regulating inflammation and immune response. Here, we review how microbiome metabolites short-chain fatty acids (SCFAs), secondary bile acids, polyamines, microbial tryptophan metabolites, and polyphenols are involved in the tumorigenesis and development of CAC through inflammation and immunity. Given the heated debate on the metabolites of microbiota in maintaining gut homeostasis, serving as tumor molecular markers, and affecting the efficacy of immune checkpoint inhibitors in recent years, strategies for the prevention and treatment of CAC by targeting intestinal microbial metabolites are also discussed in this review.

Revisiting Luteolin Against the Mediators of Human Metastatic Colorectal Carcinoma: A Biomolecular Approach

Metastatic colorectal carcinoma (mCRC) is one of the prevalent subtypes of human cancers and is caused by the alterations of various lifestyle and diet-associated factors. β-catenin, GSK-3β, PI3K-α, AKT1, and NF-κB p50 are known to be the critical regulators of tumorigenesis and immunopathogenesis of mCRC. Unfortunately, current drugs have limited efficacy, side effects and can lead to chemoresistance. Therefore, searching for a nontoxic, efficacious anti-mCRC agent is crucial and of utmost interest. The present study demonstrates the identification of a productive and nontoxic anti-mCRC agent through a five-targets (β-catenin, GSK-3β, PI3K-α, AKT1, and p50)-based and three-tier (binding affinity, pharmacokinetics, and pharmacophore) screening strategy involving a series of 30 phytocompounds having a background of anti-inflammatory/anti-mCRC efficacy alongside 5-fluorouracil (FU), a reference drug. Luteolin (a phyto-flavonoid) was eventually rendered as the most potent and safe phytocompound. This inference was verified through three rounds of validation. Firstly, luteolin was found to be effective against the different mCRC cell lines (HCT-15, HCT-116, DLD-1, and HT-29) without hampering the viability of non-tumorigenic ones (RWPE-1). Secondly, luteolin was found to curtail the clonogenicity of CRC cells, and finally, it also disrupted the formation of colospheroids, a characteristic of metastasis. While studying the mechanistic insights, luteolin was found to inhibit β-catenin activity (a key regulator of mCRC) through direct physical interactions, promoting its degradation by activating GSK3-β and ceasing its activation by inactivating AKT1 and PI3K-α. Luteolin also inhibited p50 activity, which could be useful in mitigating mCRC-associated proinflammatory milieu. In conclusion, our study provides evidence on the efficacy of luteolin against the critical key regulators of immunopathogenesis of mCRC and recommends further studies in animal models to determine the effectiveness efficacy of this natural compound for treating mCRC in the future.

Negatively Charged Thermosensitive Hydrogel Loaded with Pectin Microspheres to Recover the Mucosal Barrier for Ulcerative Colitis Therapy

Ulcerative colitis (UC), a chronic inflammatory bowel disease, poses a heightened colorectal cancer risk due to persistent mucosal inflammation and barrier dysfunction. In this article, a negatively charged thermosensitive hydrogel loaded with pectin microspheres was used as the enema for UC treatment. Succinic acid was immobilized on poly(ε-caprolactone-co-glycolide)-poly(ethylene glycol)-poly(ε-caprolactone-co-glycolide) (PCLGA-PEG-PCLGA) triblock copolymers to preferentially coat on cationic-inflamed sites via electrostatic interaction for reconstructing the mucosal barrier. Anti-inflammation drug 5-aminosalicylic acid (5-ASA) and curcumin-loaded pectin microspheres (Pec@Cur) were dispersed in the hydrogel for the inflammatory treatment of UC. The thermally sensitive hydrogels were rectally injected into UC model mice. The hydrogel effectively adhered to ulcers and prolonged colon retention, enabling sustained drug release and remarkably relieving the symptoms of colitis. The negatively charged hydrogel exhibited excellent significance in the UC treatment.

Cocoa and Polyphenol-Rich Cocoa Fractions Fail to Improve Acute Colonic Inflammation in Dextran Sulfate Sodium-Treated Mice

SCOPE

A study is conducted to determine the anti-inflammatory effects of cocoa and polyphenol-rich cocoa fractions in the dextran sulfate sodium (DSS)-induced mouse model of acute colonic inflammation.

METHODS AND RESULTS

Male C57BL/6J mice are treated with dietary cocoa powder, an extractable cocoa polyphenol fraction, or a non-extractable cocoa polyphenol fraction for 2 weeks prior to treatment with 2.5% DSS in the drinking water for 7 days to induce colonic inflammation. Cocoa treatment continues during the DSS period. Cocoa and/or cocoa fractions exacerbate DSS-induced weight loss and fail to mitigate DSS-induced colon shortening but do improve splenomegaly. Cocoa/cocoa fraction treatment fails to mitigate DSS-induced mRNA and protein markers of inflammation. Principal component analysis shows overlap between cocoa or cocoa fraction-treated mice and DSS-induced controls, but separation from mice not treated with DSS.

CONCLUSION

The results suggest cocoa and cocoa polyphenols may not be useful in mitigating acute colonic inflammation.

Cornus mas L. Extract Targets the Specific Molecules of the Th17/Treg Developmental Pathway in TNBS-Induced Experimental Colitis in Rats

Given that one of the crucial events in the pathogenesis of inflammatory bowel disease is the loss of homeostasis between Th17 and Treg cells, targeting the specific molecules of the Th17/Treg axis developmental pathway is a promising strategy for inflammatory bowel disease prevention and treatment. The current study aimed to assess the impact of cornelian cherry (Cornus mas L.) extract, rich in iridoids and polyphenols known for their potential anti-inflammatory activity, at two doses (20 or 100 mg/kg) on the crucial factors for Th17/Treg cell differentiation in the course of experimental colitis and compare this action with that of sulfasalazine. This study was conducted on the biobank colon tissue samples collected during the previous original experiment, in which colitis in rats was induced by trinitrobenzenesulfonic acid (TNBS). The levels of IL-6, RORγt, total STAT3, p-STAT3, and Foxp3 were determined by ELISA. The expression of PIAS3 mRNA was quantified by qPCR. Cornelian cherry extract at a dose of 100 mg/kg counteracted the TNBS-induced elevation of IL-6, RORγt, and p-STAT3 levels and a decrease in Foxp3 level and PIAS3 mRNA expression, while given concomitantly with sulfasalazine was more effective than sulfasalazine alone in reversing the TNBS-induced changes in IL-6, RORγt, total STAT3, p-STAT3, Foxp3 levels, and PIAS3 mRNA expression. The beneficial effect of cornelian cherry extract on experimental colitis may be due to its immunomodulatory activity reflected by the influence on factors regulating the Th17/Treg axis.

Role of interleukin-6-mediated inflammation in the pathogenesis of inflammatory bowel disease: focus on the available therapeutic approaches and gut microbiome

Inflammatory bowel disease (IBD) is considered a chronic inflammatory and multifactorial disease of the gastrointestinal tract. Crohn's disease (CD) and ulcerative colitis (UC) are two types of chronic IBD. Although there is no accurate information about IBD pathophysiology, evidence suggests that various factors, including the gut microbiome, environment, genetics, lifestyle, and a dysregulated immune system, may increase susceptibility to IBD. Moreover, inflammatory mediators such as interleukin-6 (IL-6) are involved in the immunopathogenesis of IBDs. IL-6 contributes to T helper 17 (Th17) differentiation, mediating further destructive inflammatory responses in CD and UC. Moreover, Th1-mediated responses participate in IBD, and the antiapoptotic IL-6/IL-6 receptor (IL-6R)/signal transducer and activator of transcription 3 (STAT3) signals are responsible for preserving Th1 cells in the site of inflammation. It has been revealed that fecal bacteria isolated from UC-active and UC-remission patients stimulate the hyperproduction of several cytokines, such as IL-6, tumor necrosis factor-α (TNF-α), IL-10, and IL-12. Given the importance of the IL-6/IL-6R axis, various therapeutic options exist for controlling or treating IBD. Therefore, alternative therapeutic approaches such as modulating the gut microbiome could be beneficial due to the failure of the target therapies so far. This review article summarizes IBD immunopathogenesis focusing on the IL-6/IL-6R axis and discusses available therapeutic approaches based on the gut microbiome alteration and IL-6/IL-6R axis targeting and treatment failure.

Colorectal Cancer in Ulcerative Colitis: Mechanisms, Surveillance and Chemoprevention

Patients with ulcerative colitis (UC) are at a two- to three-fold increased risk of developing colorectal cancer (CRC) than the general population based on population-based data. UC-CRC has generated a series of clinical problems, which are reflected in its worse prognosis and higher mortality than sporadic CRC. Chronic inflammation is a significant contributor to the development of UC-CRC, so comprehending the relationship between the proinflammatory factors and epithelial cells together with downstream signaling pathways is the core to elucidate the mechanisms involved in developing of CRC. Clinical studies have shown the importance of early prevention, detection and management of CRC in patients with UC, and colonoscopic surveillance at regular intervals with multiple biopsies is considered the most effective way. The use of endoscopy with targeted biopsies of visible lesions has been supported in most populations. In contrast, random biopsies in patients with high-risk characteristics have been suggested during surveillance. Some of the agents used to treat UC are chemopreventive, the effects of which will be examined in cancers in UC in a population-based setting. In this review, we outline the current state of potential risk factors and chemopreventive recommendations in UC-CRC, with a specific focus on the proinflammatory mechanisms in promoting CRC and evidence for personalized surveillance.

Exploring the Underlying Mechanism of Ren-Shen-Bai-Du Powder for Treating Inflammatory Bowel Disease Based on Network Pharmacology and Molecular Docking

Ren-Shen-Bai-Du Powder (RSBDP) is currently used for inflammatory bowel disease (IBD) therapy in China. However, its potential mechanism against IBD remains unknown. In this study, we initially identified potential targets of RSBDP against IBD through network pharmacology analysis and molecular docking. Afterwards, the DSS-induced colitis mice model was employed to assess the effects of RSBDP. The results of network pharmacology indicated that a total of 39 main active ingredients in RSBDP generated 309 pairs of drug-ingredient and ingredient-target correspondences through 115 highly relevant targets of IBD. The primary ingredients (quercetin, kaempferol, luteolin, naringenin, and sitosterol) exerted functions through multiple targets that include CYP1B1, CA4/7, and ESR1/2, etc. GO functional enrichment analysis revealed that the targets related to IBD were significantly enriched in the oxidation-reduction process, protein binding, and cytosol. Per the KEGG pathway analysis, pathways in cancer, adherens junction, and nitrogen metabolism were pivotal in the RSBDP’s treatment of IBD. Additionally, molecular docking demonstrated that a set of active ingredients and their targets displayed good bonding capabilities (e.g., kaempferol and AhR with combined energy < 5 kcal/mol). For the animal experiment, oral RSBDP promoted weight recovery, reduced intestinal inflammation, and decreased serum IL-1, IL-6, and IL-8 concentrations in the DSS + RSBDP group. Meanwhile, oral RSBDP significantly up-regulated the mRNA levels of CA7, CPY1B1, and PTPN11; in particular, the expression level of CYP1B1 in the DSS + RSBDP group was up-regulated by as high as 9-fold compared to the DSS group. Western blot results indicated that the protein levels of AKR1C1, PI3K, AKT, p-AKT, and Bcl-2 were significantly down-regulated, and Bax was significantly up-regulated in the DSS + RSBDP group. Compared to the DSS and control groups, the Bax/Bcl-2 value in the DSS + RSBDP group increased 4-fold and 8-fold, respectively, which suggested that oral RSBDP promotes apoptosis of intestinal epithelial cells. In short, this study established quercetin, kaempferol, luteolin, naringenin, and sitosterol as the primary key active ingredients of RSBDP that exert synergistic therapeutic effects against IBD through modulating the AhR/CYP1B1 and AKR1C1/PI3K/AKT pathways.

Suppression of colitis-associated colorectal cancer by scutellarin through inhibiting Hedgehog signaling pathway activity

BACKGROUND

Colitis-associated colorectal cancer (CAC) is a specific type of colorectal cancer (CRC) and mainly develops from long-term intestinal inflammation. Mounting evidence reveals that activated Hedgehog signaling pathway plays a vital role in the pathogenesis of CRC. Scutellarin is a type of phytochemical flavonoid with a powerful efficacy on various malignancies, including CRC.

AIM

Here, we studied the therapeutic effect of scutellarin on CRC and its direct regulating targets.

METHODS

The CAC model in mice was established by azomethane oxide (AOM) and sodium dextran sulfate (DSS), followed by detection of the efficacies of scutellarin on the carcinogenesis, apoptosis, inflammation, Hedgehog signaling cascade and complicated inflammatory networks in CAC tissues of mice. In CRC SW480 cells, the effects of scutellarin on malignant phenotype, apoptosis and Hedgehog signaling were examined. In TNF-α-stimulated IEC-6 intestinal epithelial cells, the actions of scutellarin on inflammatory response and Hedgehog signals were assessed as well.

RESULTS

Scutellarin significantly ameliorated AOM/DSS-caused CAC in mice and induced apoptosis in CAC tissues of mice, by inhibiting NF-κB (nuclear factor kappa B) -mediated inflammation and Hedgehog signaling axis. RNA-seq and transcriptome analysis indicated that scutellarin regulated complicated inflammatory networks in mouse CAC. Also, scutellarin suppressed the proliferation, migration, colony formation, and induced apoptosis of SW480 cells by down-regulation of Hedgehog signaling pathway activity. Additionally, scutellarin lessened NF-κB-mediated inflammatory response in TNF-α-stimulated IEC-6 cells, by attenuating Hedgehog signaling cascade.

CONCLUSION

Scutellarin potently ameliorates CAC by suppressing Hedgehog signaling pathway activity, underpinning the promising application of scutellarin to CRC in clinical settings.

Caffeic Acid Phenethyl Ester Attenuates Dextran Sulfate Sodium-Induced Ulcerative Colitis Through Modulation of NF-κB and Cell Adhesion Molecules

Ulcerative colitis (UC) is a serious health condition and defined as inflammation in the colon. Untreated, UC can develop into colitis-associated cancer (CAC), for which effective medicines are not available. Natural products are a better choice to treat UC by alleviating the inflammation. Caffeic acid phenethyl ester (CAPE) is a phenolic compound and known for its beneficial effects, including antibacterial, anti-inflammatory, anti-diabetic, and anticancer. We aimed to study the effect of CAPE on dextran sulfate sodium (DSS)-induced UC in mouse model. Administration of CAPE to DSS-induced mice protected against colon damage by improving body weight of mice, reducing the weight of spleen, and increased colon length. In addition, administration of CAPE resulted reduced the activity of myeloperoxidase (MPO) and CD68+ positive cells. Furthermore, a significant decrease in the production of key cytokines and the expression of nuclear factor (p65-NF)-κB. Moreover, p65-NF-κB activation was reduced in lipopolysaccharide (LPS)-treated RAW 264.7 macrophage cells from mouse origin. CAPE treatment leads to the reduced expressions of intercellular adhesion molecules (ICAM)-1 and vascular cell adhesion molecules (VCAM), both are key cell adhesion molecules. The results of this study clearly indicate that CAPE can potentially control inflammation in the colon and can be used as a therapy for UC.

Microbiota-Associated Metabolites and Related Immunoregulation in Colorectal Cancer

A growing body of research has found close links between the human gut microbiota and colorectal cancer (CRC), associated with the direct actions of specific bacteria and the activities of microbiota-derived metabolites, which are implicated in complex immune responses, thus influencing carcinogenesis. Diet has a significant impact on the structure of the microbiota and also undergoes microbial metabolism. Some metabolites, such as short-chain fatty acids (SCFAs) and indole derivatives, act as protectors against cancer by regulating immune responses, while others may promote cancer. However, the specific influence of these metabolites on the host is conditional. We reviewed the recent insights on the relationships among diet, microbiota-derived metabolites, and CRC, focusing on their intricate immunomodulatory responses, which might influence the progression of colorectal cancer.

Limonin modulated immune and inflammatory responses to suppress colorectal adenocarcinoma in mice model

Inflammation and compromised immune responses often increase colorectal cancer (CRC) risk. The immune-modulating effects of limonin on carcinogen/inflammation-induced colorectal cancer (CRC) were studied in mice. Male Balb/c mice were randomly assorted into three groups (n = 6): healthy control, non-treated CRC-induced (azoxymethane/dextran-sulfate-sodium AOM/DSS) control, and CRC-induced + 50 mg limonin/kg body weight. The CRC developments were monitored via macroscopic, histopathological, ELISA, and mRNA expression analyses. Limonin downregulated inflammation (TNF-α, tumor necrosis factor-α), enhanced the adaptive immune responses (CD8, CD4, and CD19), and upregulated antioxidant defense (Nrf2, SOD2) mRNA expressions. Limonin reduced serum malondialdehyde (MDA, lipid peroxidation biomarker), prostaglandin E2, and histopathology inflammation scores, while increasing reduced glutathione (GSH) in CRC-induced mice. Limonin significantly (p < 0.05) increased T cells (CD4 and CD8) and B cells (CD19) in spleen tissues. The CD335 (natural killer cells) were increased in the CRC-induced mice and limonin treatment restored them to normal levels suggesting reinstatement to normal colon conditions. Limonin apparently mitigated CRC development, by ameliorating adaptive immune responses (CD8, CD4, and CD19), reducing inflammation (serum prostaglandin E2; TNF-α, innate immune responses) and oxidative stress, and enhancing the endogenous anti-oxidation defense reactions (GSH) in CRC-induced mice.

Natural Polyphenols as Targeted Modulators in Colon Cancer: Molecular Mechanisms and Applications

Colon cancer commonly develops from long-term chronic inflammation in the intestine and seriously threatens human health. Natural polyphenols have been valued as a crucial regulator of nutrient metabolism and metabolic diseases, owing to their anti-inflammatory and antioxidant functions and the ability to maintain a balance between gut microbes and their hosts. Notably, experimental and clinical evidence has shown that natural polyphenols could act as a targeted modulator to play a key role in the prevention or treatment of colon cancer. Thus, in this review, we summarized recent advances in the possible regulatory mechanism and the potential application of natural polyphenols in colon cancer, which might be regarded as a novel platform for the colon cancer management.

Biological characteristics of IL-6 and related intestinal diseases

The intestine serves as an important digestive and the largest immune organ in the body. Interleukin-6(IL-6), an important mediator of various pathways, participates in the interactions between different kinds of cells and closely correlates with intestinal physiological and pathological condition. In this review we summarize the signaling pathways of IL-6 and its functions in maintaining intestinal homeostasis. We also explored its relation with nervous system and highlight its potential role in Parkinson's disease. Based on its specialty of the double-side influences on intestinal tumors and inflammation, we summarize how they are done through distinctive process.

Plant Polyphenols-Biofortified Foods as a Novel Tool for the Prevention of Human Gut Diseases

Plant food biofortification is recently receiving remarkable attention, as it aims to increase the intake of minerals, vitamins, or antioxidants, crucial for their contribution to the general human health status and disease prevention. In this context, the study of the plant’s secondary metabolites, such as polyphenols, plays a pivotal role for the development of a new generation of plant crops, compensating, at least in part, the low nutritional quality of Western diets with a higher quality of dietary sources. Due to the prevalent immunomodulatory activity at the intestinal level, polyphenols represent a nutritionally relevant class of plant secondary metabolites. In this review, we focus on the antioxidant and anti-inflammatory properties of different classes of polyphenols with a specific attention to their potential in the prevention of intestinal pathological processes. We also discuss the latest biotechnology strategies and new advances of genomic techniques as a helpful tool for polyphenols biofortification and the development of novel, healthy dietary alternatives that can contribute to the prevention of inflammatory bowel diseases.

Sphingosine-1-phosphate signal transducer and activator of transcription 3 signaling pathway contributes to baicalein-mediated inhibition of dextran sulfate sodium-induced experimental colitis in mice

Background:

Baicalein has been shown to have anti-inflammatory and anti-tumor activities. However, the mechanisms underlying its anti-inflammatory effect on colitis remain unclear.

Methods:

A dextran sodium sulfate (DSS)-induced model of acute colitis was established in BALB/c mice (6–8 weeks old, weighing 18–22 g). Six groups of mice received: (1) water for 10 days (control), n = 6; (2) DSS 4% solution in the drinking water for 7 days, followed by normal water for 3 days, n = 7; (3), (4), and (5) as for group 2 plus baicalein (10, 20, 40 mg/kg) administered once daily starting on day 1, n = 6; and (6) as for (2) plus 5-aminosalicylic acid (50 mg/kg) administered once daily starting on day 1, n = 6. Body weights, stool consistency, and hematochezia were recorded, and the severity of colitis was evaluated using a disease activity index. On day 11, the mice were euthanized, and organs and blood were collected for analysis. Serum inflammatory factors were detected by enzyme-linked immunosorbent assay; CD11b-positive cells were analyzed by immunofluorescence microscopy; expression of retinoic-acid-receptor-related orphan nuclear receptor gamma, sphingosine kinase 1 (SPHK1), and phosphorylated signal transducer and activator of transcription 3 (p-STAT3) was detected by immunohistochemistry; and expression of nucleotide-binding oligomerization domain 2 (NOD2), SPHK1, sphingosine 1-phosphate receptor 1 (S1PR1), total STAT3, and p-STAT3 were detected by western blotting analysis. Inter-group differences were compared using Student's t test.

Results:

Baicalein treatment dose-dependently reduced DSS-induced weight loss (P < 0.01 or P < 0.05), splenomegaly (P < 0.01), and colonic damage, as reflected by amelioration of diarrhea, rectal bleeding, and colonic ulceration, congestion, edema (shown as colon length, P < 0.05 or P < 0.01), and inflammatory cell infiltration. Baicalein also significantly decreased the levels of inflammatory mediators in the serum (P < 0.01) and colon, and significantly inhibited expression of NOD2 SPHK1, S1PR1, and p-STAT3 in the colon (P < 0.05).

Conclusions:

Baicalein treatment ameliorated colitis in mice by inhibiting S1P-STAT3 signaling, suggesting that this flavonoid might be beneficial in the treatment of colitis.

Cornelian Cherry Iridoid-Polyphenolic Extract Improves Mucosal Epithelial Barrier Integrity in Rat Experimental Colitis and Exerts Antimicrobial and Antiadhesive Activities In Vitro

Background and Aims

Inflammatory bowel disease pharmacotherapy, despite substantial progress, is still not satisfactory for both patients and clinicians. In view of the chronic and relapsing disease course and not always effective treatment with adverse effects, attempts to search for new, more efficient, and safer substances are essential and reasonable. This study was designed to elucidate the impact of cornelian cherry iridoid-polyphenolic extract (CE) and loganic acid (LA) on adherent-invasive E. coli growth and adhesion in vitro and to assess the effect of pretreatment with CE or LA on the course of intestinal inflammation in rat experimental colitis compared with sulfasalazine.

Methods

Antibacterial and antiadhesive activities of CE and LA were assessed using microdilution, Int407 cell adherence, and yeast agglutination assays. The colitis model was induced by 2,4,6-trinitrobenzenesulfonic acid. Studied substances were administered intragastrically for 16 days prior to colitis induction. Body weight loss; colon index; histological injuries; IL-23, IL-17, TNF-α, and chemerin levels; and STAT3, Muc2, and TFF3 mRNA expression were evaluated.

Results

Only CE exerted antimicrobial and antiadhesive activities in vitro and alleviated colonic symptoms. CE coadministrated with sulfasalazine was more effective than single compounds in reversing increased concentrations of TNF-α, IL-17, and chemerin and decreased Muc2 mRNA expression.

Conclusions

CE exerted a protective effect against experimental colitis via impaired mucosal epithelial barrier restoration and intestinal inflammatory response attenuation and given concomitantly with sulfasalazine counteracted colitis in a more effective way than sulfasalazine alone, which indicates their synergistic interaction. The beneficial effect of CE may also be due to its bacteriostatic and antiadhesive activities.

M10, a Myricetin-3-O-b-D-Lactose Sodium Salt, Prevents Ulcerative Colitis Through Inhibiting Necroptosis in Mice

Background

M10 is a derivative of Myricetin by adding a hydrophilic glycosylation group. Our previous study revealed that M10 by oral administration prevented colitis-associated colonic cancer (CAC) through attenuating endoplasmic reticulum stress in mice. In current study, we evaluated the inhibitory effects of M10 on ulcerative colitis in mice model, the mechanism of M10 in preventing colitis was further investigated.

Methods

Mice model of ulcerative colitis was induced by continuous oral dextran sodium sulfate (DSS). M10 was given gavage once a day for 12 consecutive weeks. Disease activity index (DAI) was recorded by analyzing the symptoms of colitis. Intestinal barrier was analyzed by the Immunofluorescence staining assay. The structure of microvilli of intestinal epithelial cells was analyzed under Transmission electron microscopy (TEM). TEM assay was also performed to determine the formation of necroptosis in the colonic epithelium with ulcerative colitis. We performed Western blotting assay to analyze the IL-6 and NF-κB pathways, as well as the cytokine cascades related to TNF-α signaling pathway during necroptosis.

Results

M10 by oral administration demonstrated a prevention of ulcerative colitis, showing a significant decrease of DAI as compared to the model mice. Pathological analysis indicated that M10 attenuated the degree of colonic inflammation in colonic tissues. M10 restored the structures of intestinal barrier damaged by DSS. M10 prevented the activation of the IL-6 and NF-κB signaling pathways in the inflamed colonic epithelium. Further, M10 prevented necroptosis in the inflamed colonic mucosal cells through down-regulating the TNF-α pathway. Importantly, M10 demonstrated higher activities in preventing ulcerative colitis than Myricetin and control drug Mesalazine.

Conclusions

Myricetin derivative M10 prevents chronic ulcerative colitis through inhibiting necroptosis. M10 could be developed as a promising drug for the treatment of chronic ulcerative colitis.

Vernodalin induces apoptosis through the activation of ROS/JNK pathway in human colon cancer cells

Colorectal cancer is one of the most leading death-causing cancers in the world. Vernodalin, a cytotoxic sesquiterpene, has been reported to possess anticancer properties against human breast cancer cells. We aimed to examine the anticancer mechanism of vernodalin on human colon cancer cells. Vernodalin was used on human colon cancer cells, HT-29 and HCT116. The cytotoxicity of vernodalin on human colon cancer cells was determined through in vitro 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl-tetrazolium bromide assay. Small interfering RNA was used to analyze the cascade activation of mitogen-activated protein kinase (MAPK) pathway, c-Jun N-terminal kinase (JNK) in HT-29, and HCT116 cells against vernodalin treatment. The protein expressions of caspase 3, Bcl-2, and Bax were examined through Western blot analysis. Immunoblot analysis on the JNK, ERK, and p38 MAPK pathways showed increased activation due to vernodalin treatment. It was proven from the JNK and p38 inhibition test that both pathways are significantly activated by vernodalin to induce apoptosis. Our results, collectively, showed the apoptosis-induced anticancer mechanism of vernodalin on human colon cancer cells that was mediated through the activation of JNK pathway and apoptotic regulator proteins. These results suggest that vernodalin could be developed as a potent chemotherapeutic agent for human colorectal cancer treatment.

Apoptosis Exerts a Vital Role in the Treatment of Colitis-Associated Cancer by Herbal Medicine

Colitis-associated cancer (CAC) is known as inflammatory bowel disease (IBD)-developed colorectal cancer, the pathogenesis of which involves the occurrence of apoptosis. Western drugs clinically applied to CAC are often single-targeted and exert many adverse reactions after long-term administration, so it is urgent to develop new drugs for the treatment of CAC. Herbal medicines commonly have multiple components with multiple targets, and most of them are low-toxicity. Some herbal medicines have been reported to ameliorate CAC through inducing apoptosis, but there is still a lack of systematic review. In this work, we reviewed articles published in Sci Finder, Web of Science, PubMed, Google Scholar, CNKI, and other databases in recent years by setting the keywords as apoptosis in combination with colitis-associated cancer. We summarized the herbal medicine extracts or their compounds that can prevent CAC by modulating apoptosis and analyzed the mechanism of action. The results show the following. (1) Herbal medicines regulate both the mitochondrial apoptosis pathway and death receptor apoptosis pathway. (2) Herbal medicines modulate the above two apoptotic pathways by affecting signal transductions of IL-6/STAT3, MAPK/NF-κ B, Oxidative stress, Non-canonical TGF-β1, WNT/β-catenin, and Cell cycle, thereby ameliorating CAC. We conclude that following. (1) Studies on the role of herbal medicine in regulating apoptosis through the Ras/Raf/ERK, WNT/β-catenin, and Cell cycle pathways have not yet been carried out in sufficient depth. (2) The active constituents of reported anti-CAC herbal medicine mainly include polyphenols, terpenoids, and saccharide. Also, we identified other herbal medicines with the constituents mentioned above as their main components, aiming to provide a reference for the clinical use of herbal medicine in the treatment of CAC. (3) New dosage forms can be utilized to elevate the targeting and reduce the toxicity of herbal medicine.

Combination of Inositol Hexaphosphate and Inositol Inhibits Liver Metastasis of Colorectal Cancer in Mice Through the Wnt/β-Catenin Pathway

Introduction

Colorectal cancer, one of the most common tumors, is mainly fatal because of the occurrence of liver metastasis. Inositol hexaphosphate (IP6) and inositol (INS) were found, both, in vitro and in vivo to play an anti-tumor effect, whereas the combination of IP6 and INS was more effective than IP6 or INS alone.

Materials and Methods

The inhibitory effects of IP6, INS and the combination of IP6+INS on tumor progression and liver metastasis of colorectal cancer were investigated in an orthotopic transplantation model of colorectal cancer. The tumor-bearing mice were selected by in vivo bioluminescence imaging and were treated with IP6, INS, and IP6 combined with INS, respectively. All mice were sacrificed after 6 weeks of treatment. The cancer development and metastasis were compared among the groups. The expression of genes related to the Wnt/β-catenin in the model was analyzed.

Results

The results demonstrated that liver metastasis was inhibited after treatment with IP6, INS, and IP6+INS. Compared to that of the M_G, survival period was extended, and tumor weight was lowered in IP6_G, INS_G, and IP6+INS_G. Besides, the liver metastatic area of mice in IP6+INS_G was relatively smaller than that in M_G, IP6_G, or INS_G. The results of RNA-seq analysis showed that the expressions of Wnt10b, Tcf7, and c-Myc were significantly downregulated in IP6+INS_G compared to that in M_G (P<0.05). Results of real-time PCR and Western blot showed that mRNA and protein expressions of β-catenin, Wnt10b, Tcf7, and c-Myc were significantly lower in IP6+INS_G compared to that in M_G (P<0.05).

Discussion

IP6+INS was more effective in inhibiting liver metastasis of colorectal cancer than IP6 or INS alone. The better inhibition effect may be accomplished through regulating the mutation of Wnt/β-catenin signaling pathway by inhibiting Wnt10b, Tcf7, β-catenin, and c-Myc from abnormally high expression.

Interplay between Dietary Polyphenols and Oral and Gut Microbiota in the Development of Colorectal Cancer

Colorectal cancer (CRC) is the third most diagnosed type of cancer worldwide. Dietary features play an important role in its development, and the involvement of human microbial communities in this pathology has also recently been recognized. Individuals with CRC display alterations in gut bacterial composition and a notably higher abundance of putative oral bacteria in colonic tumors. Many experimental studies and preclinical evidence propose that dietary polyphenols have a relevant role in CRC development and progression, mainly attributed to their immunomodulatory activities. Furthermore, polyphenols can modulate oral and gut microbiota, and in turn, intestinal microbes catabolize polyphenols to release metabolites that are often more active and better absorbed than the original phenolic compounds. The current study aimed to review and summarize current knowledge on the role of microbiota and the interactions between dietary polyphenols and microbiota in relation to CRC development. We have highlighted the mechanisms by which dietary polyphenols and/or their microbial metabolites exert their action on the pathogenesis and prevention of CRC as modulators of the composition and/or activity of oral and intestinal microbiota, including novel screening biomarkers and possible nutritional therapeutic implications.

Chocolate, "Food of the Gods": History, Science, and Human Health

Chocolate is well known for its fine flavor, and its history began in ancient times, when the Maya considered chocolate (a cocoa drink prepared with hot water) the "Food of the Gods". The food industry produces many different types of chocolate: in recent years, dark chocolate, in particular, has gained great popularity. Interest in chocolate has grown, owing to its physiological and potential health effects, such as regulation of blood pressure, insulin levels, vascular functions, oxidation processes, prebiotic effects, glucose homeostasis, and lipid metabolism. However, further translational and epidemiologic studies are needed to confirm available results and to evaluate other possible effects related to the consumption of cocoa and chocolate, verifying in humans the effects hitherto demonstrated only in vitro, and suggesting how best to consume (in terms of dose, mode, and time) chocolate in the daily diet.

Inflammation and Inflammatory Cytokine Contribute to the Initiation and Development of Ulcerative Colitis and Its Associated Cancer

Dysregulated inflammatory responses play a pivotal role in the initiation, development, and progression of tumors, as demonstrated by the association between ulcerative colitis and the increased risk of colon carcinoma. In this review, the underlying mechanisms for the initiation and development of ulcerative colitis and colitis-associated cancer are described, mainly focusing on the inflammation and inflammatory cytokine. Disruption of the intestinal mucosal barrier and bacterial invasion resulted in intestinal inflammation; and further TLR4/NF-κB stimulation in intestinal epithelial cells, inflammatory cell infiltration, and inflammatory cytokine release all confer survival advantages to or promote abnormal proliferation in susceptible cells. Importantly, the respective roles of TLR4/NF-κB, TNF-α, and IL-6 in intestinal epithelial cells and inflammatory cells are summarized in detail. A thorough understanding of these molecular mechanisms may help researchers and clinicians to explore novel approaches for the prevention and treatment of colitis-associated cancer.

Dietary Fat-Accelerating Leptin Signaling Promotes Protumorigenic Gastric Environment in Mice

Excess of fat intake leads to obesity and causes a variety of metabolic diseases and cancer. We previously demonstrated that high-lard diet induces intestinal metaplasia, a precancerous lesion of the stomach mediated by leptin signaling. This study aims to investigate which kinds of dietary fat cause the intestinal metaplasia onset. We fed eight kinds of high-fat diets (HFDs) of animal or plant origin to mice evaluated their effect on gastric pathogenesis. Five types of dietary fat were divided according to their observed effects: Obese with high metaplasia (group I; beef tallow, lard, and hydrogenated coconut oil), non-obese with high metaplasia (group II; linseed oil), obese without metaplasia (group III; corn oil and olive oil), non-obese without metaplasia (group IV, soybean oil) and lean without metaplasia (group V; cocoa butter). The group I and II diets induced leptin, phosphorylated leptin receptor (ObR), signal transducer and activator 3 (STAT3), and increased intracellular β-catenin accumulation in the stomach. Moreover, mice fed these HFDs with 1-methyl-3-nitro-1-nitrosoguanidine (MNNG), a gastric carcinogen, and further accelerated dysplasia in the stomach. Lactobacillus occupancy in the stomach increased in all HFDs except hydrogenated coconut oil. Our findings suggest that HFDs inducing leptin signaling accelerate the enhancement of protumorigenic gastric microenvironment independent of body mass gain or microbiome changes.

Natural flavonoids for the prevention of colon cancer: A comprehensive review of preclinical and clinical studies

Flavonoids comprise a group of natural polyphenols consisting of more than 5,000 subtypes mostly existing in fruits and vegetables. Flavonoids consumption could potentially attenuate the incidence and recurrence risk of colorectal cancers through their antiperoxidative, antioxidant, and anti-inflammatory effects. In addition, these compounds regulate the mitochondrial function, balance the bacterial flora and promote the apoptosis process in cancerous cells. However, some previous data failed to show the effectiveness of flavonoids in reducing the risk of colorectal cancer. In this study, we have reviewed the efficacy of different flavonoids subtypes on the risk of colon cancer and molecular mechanisms involved in this process in both clinical and animal studies. In addition, we tried to elucidate the potential synergy between these compounds and current colorectal cancer treatments.

Polyphenols: Immunomodulatory and Therapeutic Implication in Colorectal Cancer

Polyphenolic compounds, widely present in fruits, vegetables, and cereals, have potential benefits for human health and are protective agents against the development of chronic/degenerative diseases including cancer. More recently these bioactive molecules have been gaining great interest as anti-inflammatory and immunomodulatory agents, mainly in neoplasia where the pro-inflammatory context might promote carcinogenesis. Colorectal cancer (CRC) is considered a major public healthy issue, a leading cause of cancer mortality and morbidity worldwide. Epidemiological, pre-clinical and clinical investigations have consistently highlighted important relationships between large bowel inflammation, gut microbiota (GM), and colon carcinogenesis. Many experimental studies and clinical evidence suggest that polyphenols have a relevant role in CRC chemoprevention, exhibit cytotoxic capability vs. CRC cells and induce increased sensitization to chemo/radiotherapies. These effects are most likely related to the immunomodulatory properties of polyphenols able to modulate cytokine and chemokine production and activation of immune cells. In this review we summarize recent advancements on immunomodulatory activities of polyphenols and their ability to counteract the inflammatory tumor microenvironment. We focus on potential role of natural polyphenols in increasing the cell sensitivity to colon cancer therapies, highlighting the polyphenol-based combined treatments as innovative immunomodulatory strategies to inhibit the growth of CRC.

Obesity-Induced TNFα and IL-6 Signaling: The Missing Link between Obesity and Inflammation-Driven Liver and Colorectal Cancers

Obesity promotes the development of numerous cancers, such as liver and colorectal cancers, which is at least partly due to obesity-induced, chronic, low-grade inflammation. In particular, the recruitment and activation of immune cell subsets in the white adipose tissue systemically increase proinflammatory cytokines, such as tumor necrosis factor α (TNFα) and interleukin-6 (IL-6). These proinflammatory cytokines not only impair insulin action in metabolic tissues, but also favor cancer development. Here, we review the current state of knowledge on how obesity affects inflammatory TNFα and IL-6 signaling in hepatocellular carcinoma and colorectal cancers.

Inositol-6 phosphate inhibits the mTOR pathway and induces autophagy-mediated death in HT-29 colon cancer cells

INTRODUCTION

Colorectal cancer (CRC) is common, with a worldwide incidence estimated at more than 1 million cases annually. Therefore, the search for agents for CRC treatment is highly warranted. Inositol-6 phosphate (IP₆) is enriched in rice bran and possesses many beneficial effects. In the present study the effect of IP6 on autophagy-mediated death by modulating the mTOR pathway in HT-29 colon cancer cells was studied.

MATERIAL AND METHODS

Autophagy was assessed by acridine orange (AO) staining, transmission electron microscopy, and western blotting to detect LC3-II and Beclin 1. Akt/mTOR signaling protein expression was also analyzed by western blotting. Apoptosis was analyzed by annexin V staining.

RESULTS

Incubation of cells with IP₆ resulted in downregulation of the p-Akt at 3h. Along with that confocal microscopic analysis of p-AKT, IP₆ administration resulted that a diminished expression of p-Akt. mTOR pathway regulates autophagy and incubation with IP6 to HT-29 cells showed decreased expression of p-70S6Kinase, 4-EBP-1 in a time-dependent manner. Inositol-6 phosphate (10 μg/ml, 24 and 48 h) induced autophagic vesicles, as confirmed by AO staining and transmission electron microscopy. We also found increased expression of LC3-II and Beclin 1 in a time-dependent manner after incubation with IP₆. Furthermore, IP₆ induced apoptosis, as revealed by annexin V staining.

CONCLUSIONS

Our results clearly indicate that IP6 induces autophagy by inhibiting the Akt/mTOR pathway.

An update on dietary consideration in inflammatory bowel disease: anthocyanins and more

Inflammatory bowel disease (IBD) is a chronic idiopathic inflammatory disorder. A wealth of data pointed out that various aspects of chronic inflammation may be affected by several specific dietary factors. This paper calls attention to anthocyanins enriched plant food and anthocyanin dietary supplements, whose role in the management of IBD and its associated oncogenesis deems crucial. Area covered: We updated the most relevant dietary anthocyanins with potential anti-colitis and preventive effect on inflammatory associated colorectal cancer based on the recent animal and human researches along with revealing the major cellular and molecular mechanisms of action. Mounting evidence reported that anthocyanins enriched plant foods perform their protective role on IBD and inflammatory-induced colorectal cancer via different cellular transduction signaling pathways, including inflammatory transcription factors, SAPK/JNK and p38 MAPK cascade, JAK/STAT signaling, NF-kB/pERK/MAPK, Wnt signaling pathway, Nrf2 cytoprotective pathway as well as AMPK pathway and autophagy. Expert commentary: Combination of anthocyanins enriched dietary supplements with existing medications can provide new therapeutic options for IBD patients. Further, well-designed randomized control trials (RCTs) are essential to evaluate the role of anthocyanins enriched medicinal foods as well as isolated anthocyanin components as promising preventive and therapeutic dietary agents for IBD and its associated oncogenesis.

PMA treated THP-1-derived-IL-6 promotes EMT of SW48 through STAT3/ERK-dependent activation of Wnt/β-catenin signaling pathway

Colon cancer is one of the most common digestive malignant tumors that leads to high mortality worldwide, and metastasis is the primary cause of cancer-related death. It is well accepted that the epithelial-mesenchymal transition (EMT) plays a key role in the process of metastasis. As a cytokine that macrophage secretes, IL-6 is involved in the progression of tumors, including the invasion and metastasis via kinds of signaling pathways. However, the mechanism of interactions between IL-6, macrophage, EMT and colon cancer is not fully understood. Increased CD68⁺ macrophages and IL-6 level were found in colon tumor as compared to normal colon tissue. Metastatic lymph node showed even more CD68⁺ macrophages and higher IL-6 level than the primary tumor. These results suggested that macrophages and IL-6 play an important role in EMT of colon cancer. In order to investigate the effect of macrophage and IL-6 on EMT of colon cancer, we cultured human colon carcinoma cell line SW48 with conditioned medium (CM) from PMA-stimulated monocyte THP-1 cells and tested for IL-6 dependent EMT pathways. Wound healing assay and Transwell assay were used to analyze cell migration and invasion. Results showed that CM-treated SW48 cells increased IL-6 production and displayed elevated capacity of migration and invasion compared to untreated cells. Increased expressions of EMT markers (N-cadherin, Vimentin and β-catenin) and decreased expression of EMT marker(E-cadherin) were found in CM-treated SW48 cells by Western Blot. The addition of an anti-IL-6 antibody significantly inhibited the increase of EMT markers (Vimentin and β-catenin) as well as cell migration and invasion, suggesting that IL-6 played a critical role in promoting EMT of CM-treated SW48 cells. In addition, we found that the levels of p-STAT3 and p-ERK increased in CM-treated SW48 compared to untreated cells, which can be reversed by AG490, an inhibitor of JAK. In the meantime, the suppression of JAK-associated signaling pathways caused a decrease of β-catenin. In summary, our study suggested that macrophage-induced IL-6 promotes migration and invasion of colon cancer cell via Wnt/β-catenin pathway in STAT3/ERK-dependent way.

Secretory leukoprotease inhibitor is required for efficient quercetin-mediated suppression of TNFα secretion

Dendritic cells (DCs) are professional antigen presenting cells (APCs) that in response to microbial infections generate long-lasting adaptive immune response. Following microbial uptake, DCs undergo a cascade of cellular differentiation that ultimately leads to “mature” DCs. Mature DCs produce a variety of inflammatory cytokines, including tumor necrosis factor-α (TNFα) a key cytokine for the inflammatory cascade. In numerous studies, polyphenols, including quercetin, demonstrated their ability to suppress TNFα secretion and protect from the onset of chronic inflammatory disorders. We show that murine bone marrow derived DCs express Slpi following quercetin exposure. Slpi is known to suppress LPS mediated NFκB activation, thus, it was hypothesized that its expression could be the key step for polyphenol induced inflammatory suppression. Slpi-KO DCs poorly respond to quercetin administration failing to reduce TNFα secretion in response to quercetin exposure. Supernatant from quercetin exposed DCs could also reduce LPS-mediated TNFα secretion by unrelated DCs, but this property is lost using an anti-Slpi antibody. In vivo, oral administration of quercetin is able to induce Slpi expression. Human biopsies from inflamed tract of the intestine reveal the presence of numerous SLPI⁺ cells and the expression level could be further increased by quercetin administration. We propose that quercetin induces Slpi expression that in turn reduces the inflammatory response. Our data encourages the development of nutritional strategies to improve the efficiency of current therapies for intestinal chronic inflammatory syndrome and reduce the risks of colorectal cancer development.

Polyphenolic Phytochemicals in Cancer Prevention and Therapy: Bioavailability versus Bioefficacy

Natural polyphenols are organic chemicals which contain phenol units in their structures. They show antitumor properties. However, a key problem is their short half-life and low bioavailability under in vivo conditions. Still, definitively demonstrating the human benefits of isolated polyphenolic compounds (alone or in combination) using modern scientific methodology has proved challenging. The most common discrepancy between experimental and clinical observations is the use of nonphysiologically relevant concentrations of polyphenols in mechanistic studies. Thus, it remains highly controversial how applicable underlying mechanisms are with bioavailable concentrations and biological half-life. The present Perspective analyses proposed antitumor mechanisms, in vivo reported antitumor effects, and possible mechanisms that may explain discrepancies between bioavailability and bioefficacy. Polyphenol metabolism and possible toxic side effects are also considered. Our main conclusion emphasizes that these natural molecules (and their chemical derivatives) indeed can be very useful, not only as cancer chemopreventive agents but also in oncotherapy.

Interferon regulatory factor signaling in autoimmune disease

Interferon regulatory factors (IRFs) play critical roles in pathogen-induced innate immune responses and the subsequent induction of adaptive immune response. Dysregulation of IRF signaling is therefore thought to contribute to autoimmune disease pathogenesis. Indeed, numerous murine in vivo studies have documented protection from or enhanced susceptibility to particular autoimmune diseases in Irf-deficient mice. What has been lacking, however, is replication of these in vivo observations in primary immune cells from patients with autoimmune disease. These types of studies are essential as the majority of in vivo data support a protective role for IRFs in Irf-deficient mice, yet IRFs are often found to be overexpressed in patient immune cells. A significant body of work is beginning to emerge from both of these areas of study - mouse and human.

Bioactivity of Polyphenols: Preventive and Adjuvant Strategies toward Reducing Inflammatory Bowel Diseases-Promises, Perspectives, and Pitfalls

Inflammatory bowel diseases (IBDs) are characterized by autoimmune and inflammation-related complications of the large intestine (ulcerative colitis) and additional parts of the digestive tract (Crohn's disease). Complications include pain, diarrhoea, chronic inflammation, and cancer. IBD prevalence has increased during the past decades, especially in Westernized countries, being as high as 1%. As prognosis is poor and medication often ineffective or causing side effects, additional preventive/adjuvant strategies are sought. A possible approach is via diets rich in protective constituents. Polyphenols, the most abundant phytochemicals, have been associated with anti-inflammatory, antioxidant, immunomodulatory, and apoptotic properties. Locally reducing oxidative stress, they can further act on cellular targets, altering gene expression related to inflammation, including NF-κB, Nrf-2, Jak/STAT, and MAPKs, suppressing downstream cytokine formation (e.g., IL-8, IL-1β, and TNF-α), and boosting the bodies' own antioxidant status (HO-1, SOD, and GPx). Moreover, they may promote, as prebiotics, healthy microbiota (e.g., Bifidobacteria, Akkermansia), short-chain fatty acid formation, and reduced gut permeability/improved tight junction stability. However, potential adverse effects such as acting as prooxidants, or perturbations of efflux transporters and phase I/II metabolizing enzymes, with increased uptake of undesired xenobiotics, should also be considered. In this review, we summarize current knowledge around preventive and arbitrary actions of polyphenols targeting IBD.

Effect of Cocoa and Its Flavonoids on Biomarkers of Inflammation: Studies of Cell Culture, Animals and Humans

Chronic inflammation has been identified as a necessary step to mediate atherosclerosis and cardiovascular disease and as a relevant stage in the onset and progression of several types of cancer. Considerable attention has recently been focused on the identification of dietary bioactive compounds with anti-inflammatory activities as an alternative natural source for prevention of inflammation-associated diseases. The remarkable capacity of cocoa flavanols as antioxidants, as well as to modulate signaling pathways involved in cellular processes, such as inflammation, metabolism and proliferation, has encouraged research on this type of polyphenols as useful bioactive compounds for nutritional prevention of cardiovascular disease and cancer. Data from numerous studies suggest that cocoa and cocoa-derived flavanols can effectively modify the inflammatory process, and thus potentially provide a benefit to individuals with elevated risk factors for atherosclerosis/cardiovascular pathology and cancer. The present overview will focus on the most recent findings about the effects of cocoa, its main constituents and cocoa derivatives on selected biomarkers of the inflammatory process in cell culture, animal models and human cohorts.

Preventive Effects of Cocoa and Cocoa Antioxidants in Colon Cancer

Colorectal cancer is one of the main causes of cancer-related mortality in the developed world. Carcinogenesis is a multistage process conventionally defined by the initiation, promotion and progression stages. Natural polyphenolic compounds can act as highly effective antioxidant and chemo-preventive agents able to interfere at the three stages of cancer. Cocoa has been demonstrated to counteract oxidative stress and to have a potential capacity to interact with multiple carcinogenic pathways involved in inflammation, proliferation and apoptosis of initiated and malignant cells. Therefore, restriction of oxidative stress and/or prevention or delayed progression of cancer stages by cocoa antioxidant compounds has gained interest as an effective approach in colorectal cancer prevention. In this review, we look over different in vitro and in vivo studies that have identified potential targets and mechanisms whereby cocoa and their flavonoids could interfere with colonic cancer. In addition, evidence from human studies is also illustrated.