Antiproliferative and apoptotic-inducing potential of ellagic acid against 1,2-dimethyl hydrazine-induced colon tumorigenesis in Wistar rats

A comprehensive review on Ellagic acid in breast cancer treatment: From cellular effects to molecular mechanisms of action

Globally, breast cancer (BC) is the leading cause of cancer-related deaths in women. Hence, developing a therapeutic plan to overcome the disease is crucial. Numerous factors such as endogenous hormones and environmental factors may play a role in the pathophysiology of BC. Regarding the multi-modality treatment of BC, natural compounds like ellagic acid (EA) received has received increased interest in antitumor efficacy with lower adverse effects. Based on the results of this comprehensive review, EA has multiple effects on BC cells including (1) suppresses the growth of BC cells by arresting the cell cycle in the G0/G1 phase, (2) suppresses migration, invasion, and metastatic, (3) stimulates apoptosis in MCF-7 cells via TGF-β/Smad3 signaling axis, (4) inhibits CDK6 that is important in cell cycle regulation, (5) binds to ACTN4 and induces its degradation via the ubiquitin-proteasome pathway, inducing decreased cell motility and invasion in BC cells, (6) inhibits the PI3K/AKT pathway, and (7) inhibits angiogenesis-associated activities including proliferation (reduces VEGFR-2 tyrosine kinase activity). In conclusion, EA exhibits anticancer activity through various molecular mechanisms that influence key cellular processes like apoptosis, cell cycle, angiogenesis, and metastasis in BC. However, further researches are essential to fully elucidate its molecular targets and implications for clinical applications.

Effect of Diacerein on HOTAIR/IL-6/STAT3, Wnt/β-Catenin and TLR-4/NF-κB/TNF-α axes in colon carcinogenesis

Colorectal cancer (CRC) is a common malignancy with high mortality and poor prognosis. Diacerein (DIA) is an anti-inflammatory used for treatment of osteoarthritis. We delineated some underlying molecular mechanisms of DIA's anti-carcinogenic effect in CRC using in vivo and in vitro models. Human Caco-2 cells were treated with DIA followed by MTT and Annexin V assays and CRC was experimentally induced using 1,2-dimethylhydrazine. DIA (50 mg/kg/day, orally) was administrated for 8 weeks. The MTT assay confirmed cytotoxic effect of DIA in vitro and Annexin V confirmed its apoptotic effect. DIA resulted in regression of tumour lesions with reduced colonic TLR4, NF-κB and TNF-α protein levels and down-regulated VEGF expression, confirming anti-angiogenic impact. DIA triggered caspase-3 expression and regulated Wnt/β-Catenin pathway, by apparently interrupting the IL-6/STAT3/ lncRNA HOTAIR axis. In conclusion, DIA disrupted IL-6/STAT3/ lncRNA HOTAIR axis which could offer an effective therapeutic strategy for the management of CRC.

Evidence for Anticancer Effects of Chinese Medicine Monomers on Colorectal Cancer

Colorectal cancer is one of the most commonly occurring cancers worldwide. Although clinical reports have indicated the anticancer effects of Chinese herbal medicine, the multiple underlying molecular and biochemical mechanisms of action remain to be fully characterized. Chinese medicine (CM) monomers, which are the active components of CM, serve as the material basis of the functional mechanisms of CM. The aim of this review is to summarize the current experimental evidence from in vitro, in vivo, and clinical studies for the effects of CM monomers in colorectal cancer prevention and treatment, providing some useful references for future research.

The effects of ellagic acid and other pomegranate (Punica granatum L.) derivatives on human gastric cancer AGS cells

Although surgery with or without (neo)adjuvant chemo/radiotherapy, as the standard treatments, can be suitable therapeutic strategies for gastric cancer, side effects and drug resistance are two main treatment obstacles. It has been discovered that pomegranate and its natural derivatives, especially ellagic acid (EA), offer significant anti-cancer effects while causing trivial side effects. In this study, we aimed to explore the anti-cancer effects of EA on a human gastric adenocarcinoma cell line (AGS) as well as in immunocompromised mice bearing human gastric tumors, for the first time. HPLC was used for determining EA in samples. MTT assay, apoptosis and scratch assay, gelatin zymography, and quantitative RT-PCR were used to determine the anti-cancer properties of different concentrations of pomegranate fruit juice, pomegranate peel extract, and EA. Furthermore, the effects of these compounds were investigated on immunosuppressed C57BL/6 mice carrying human gastric cancer tumors. EA could inhibit the proliferation and migration of gastric cancer cells. It also had significant effects on reducing both expression and activity of MMP-2 and MMP-9. Further, it was demonstrated that with alterations in the expression of genes involved in apoptosis and inflammation including P53, BAX, APAF1, BCL2, iNOS, NF-κB, IL-8, and TNF-α, EA treatment led to increased cancer cell death and reduced inflammation. Furthermore, its use in mice bearing gastric tumors resulted in a significant reduction in tumor volume without any obvious side effects. Ellagic acid exhibited anti-cancer effects on gastric adenocarcinoma, and can be considered as a safe anti-cancer agent for further preclinical studies on this cancer.

A Comprehensive Overview of Colon Cancer- A Grim Reaper of the 21st Century

A few decades ago, the incidence of colorectal cancer (CRC) was low and is now the fourth in the list of deadly cancers producing nearly a million deaths annually. A population that is aging along with risk factors such as smoking, obesity, sedentary lifestyle with little or no physical activity, and non-healthy food habits of developed countries can increase the risk of colorectal cancer. The balance in gut microbiota and the metabolites produced during bacterial fermentation within the host plays a significant role in regulating intestinal diseases as well as colorectal cancer development. Recent progress in the understanding of illness resulted in multiple treatment options such as surgery, radiation, and chemotherapy, including targeted therapy and multitherapies. The treatment plan for CRC depends on the location, stage and grade of cancer as well as genomic biomarker tests. Despite all the advancements made in the genetic and molecular aspects of the disease, the knowledge seems inadequate as the drug action as well as the wide variation in drug response did not appear strongly correlated with the individual molecular and genetic characteristics, which suggests the requirement of comprehensive molecular understanding of this complex heterogeneous disease. Furthermore, multitherapies or a broad spectrum approach, which is an amalgamation of the various promising as well as effective therapeutic strategies that can tackle heterogeneity and act on several targets of the disease, need to be validated in clinical studies. The latest treatment options have significantly increased the survival of up to three years in the case of advanced disease. The fact that colorectal cancer is developed from a polypoid precursor, as well as the symptoms of the disease that occur at an advanced stage, underlines how screening programs can help early detection and decrease mortality as well as morbidity from CRC.

Consumption evaluation of one apple flesh a day in the initial phases prior to adenoma/adenocarcinoma in an azoxymethane rat colon carcinogenesis model

Colorectal cancer (CRC) is the fourth cancer with the most new cases reported in 2018 worldwide. Consumption of fruit and vegetables is a protective factor against the risk of CRC. Beyond this, flavonoids could orchestrate these healthy effects. Apart from containing the typical apple flavonoids, red-fleshed apples also contain anthocyanins, mainly cyanidin-3-O-galactoside (Cy3Gal). Through an azoxymethane rat carcinogenesis model, a study was carried out in order to assess the possible protective effects of apple polyphenols, with special attention to anthocyanins. In addition, apart from negative and positive controls, a group with chemotherapy with 5-fluorouracil (5FU) was included to compare their performance against the output collected from the animal treatments with white-fleshed apple (WF), red-fleshed apple (RF) and Cy3Gal (AE). Although the 5FU group presented the best performance towards aberrant crypt foci (ACF) inhibition (70.1%), rats fed with white-fleshed apples ('Golden Smoothee') were able to achieve 41.3% ACF inhibition, while none of the challenged treatments (WF, RF and AE) suffered mucin depletion in their colonocytes. Expression changes of 17 genes related to CRC were assessed. In detail, the ACF inhibition phenotype detected in 5FU and WF groups could be explained through the expression changes detected in the apoptosis-related genes of Aurka, p53 and Cox2. Moreover, in the apple consumption groups (WF and RF), a reduced protein expression of matrix metalloproteinases with gelatinase activity (MMP-2 and 9) was detected. Overall, our study suggests an effect of apple polyphenols and apple anthocyanin Cy3Gal against colon carcinogenesis, retarding/diminishing the appearance of the precancerous markers studied.

The anti-tumourigenic effect of ellagic acid in SKOV-3 ovarian cancer cells entails activation of autophagy mediated by inhibiting Akt and activating AMPK

This study investigated the effect of ellagic acid (EA) on SKOV-3 cell growth and invasiveness and tested if the underlying mechanism involves modulating autophagy. Cells were treated with EA in the presence or absence of chloroquine (CQ), an autophagy inhibitor, compound C (CC), an AMPK inhibitor, or an insulin-like growth factor-1 (IGF-1), a PI3K/Akt activator. EA, at an IC₅₀ of 36.6 µmol/L, inhibited cell proliferation, migration, and invasion and induced cell apoptosis in SKOV-3 cells. These events were prevented by CQ. Also, EA increased levels of Beclin-1, ATG-5, LC3I/II, Bax, cleaved caspase-3/8 and reduced those of p62 and Bcl-2 in these cancer cells. Mechanistically, EA decreased levels of p-S6K1 (Thr³⁸⁹ ) and 4EBP-1 (Thr^37/46 ), two downstream targets of mTORC1, and p-Akt (Thr³⁰⁸ ) but increased levels of AMPK (Thr¹⁷² ) and p-raptor (Ser⁷⁹² ), a natural inhibitor of mTORC1. CC or IGF-1 alone partially prevented the effect of EA on cell survival, cell invasions, and levels of LDH, Beclin-1, and cleaved caspase-3. In conclusion, EA can inhibit SKOV-3 growth, migration, and invasion by activating cytotoxic autophagy mediated by inhibition of mTORC1 and Akt and activation of AMPK.

Ellagic acid exerts antitumor effects via the PI3K signaling pathway in endometrial cancer

Ellagic acid (EA) is a polyphenol found in several fruits and plants. EA has been reported to exert antitumor activity in many types of cancers. However, the effect and potential molecular mechanism of EA in endometrial cancer are still unclear. Therefore, the aim of this study was to explore the underlying antitumor function and targets by which EA inhibits endometrial cancer. By using multiplatform bioinformatics analysis tools, including DrugBank, STRING, WebGestalt and cBioPortal, the core targets of EA were identified as PIK3CA and PIK3R1. In addition, through transwell assays, EA was strongly found to inhibit cell invasion and migration. Based on CCK8 assays and flow cytometry, EA exhibited a suppressive effect on endometrial cancer cell proliferation by causing cell cycle arrest and inducing apoptosis. The results of real-time PCR confirmed that the expression of PIK3CA and PIK3R was decreased by EA. Furthermore, western blotting analysis demonstrated that EA inhibited PI3K phosphorylation, downregulating the expression of MMP9. In vivo, EA suppressed lung metastasis in BALB/c nude mice based on the SUVmax value determined from PET scans and HE staining. According to all these data, it comprehensively demonstrated the inhibitory effect of EA on endometrial cancer through bioinformatics analysis and experimental verification. Our findings suggest that EA may potentially be beneficial for treating endometrial cancer.

Dietary phytochemicals in colorectal cancer prevention and treatment: A focus on the molecular mechanisms involved

Worldwide, colorectal cancer (CRC) remains a major cancer type and leading cause of death. Unfortunately, current medical treatments are not sufficient due to lack of effective therapy, adverse side effects, chemoresistance and disease recurrence. In recent decades, epidemiologic observations have highlighted the association between the ingestion of several phytochemical-enriched foods and nutrients and the lower risk of CRC. According to preclinical studies, dietary phytochemicals exert chemopreventive effects on CRC by regulating different markers and signaling pathways; additionally, the gut microbiota plays a role as vital effector in CRC onset and progression, therefore, any dietary alterations in it may affect CRC occurrence. A high number of studies have displayed a key role of growth factors and their signaling pathways in the pathogenesis of CRC. Indeed, the efficiency of dietary phytochemicals to modulate carcinogenic processes through the alteration of different molecular targets, such as Wnt/β-catenin, PI3K/Akt/mTOR, MAPK (p38, JNK and Erk1/2), EGFR/Kras/Braf, TGF-β/Smad2/3, STAT1-STAT3, NF-кB, Nrf2 and cyclin-CDK complexes, has been proven, whereby many of these targets also represent the backbone of modern drug discovery programs. Furthermore, epigenetic analysis showed modified or reversed aberrant epigenetic changes exerted by dietary phytochemicals that led to possible CRC prevention or treatment. Therefore, our aim is to discuss the effects of some common dietary phytochemicals that might be useful in CRC as preventive or therapeutic agents. This review will provide new guidance for research, in order to identify the most studied phytochemicals, their occurrence in foods and to evaluate the therapeutic potential of dietary phytochemicals for the prevention or treatment of CRC by targeting several genes and signaling pathways, as well as epigenetic modifications. In addition, the results obtained by recent investigations aimed at improving the production of these phytochemicals in genetically modified plants have been reported. Overall, clinical data on phytochemicals against CRC are still not sufficient and therefore the preventive impacts of dietary phytochemicals on CRC development deserve further research so as to provide additional insights for human prospective studies.

Protective Effect of Chickpea Protein Hydrolysates on Colon Carcinogenesis Associated With a Hypercaloric Diet

OBJECTIVE

Colon cancer occupies the third place in incidence worldwide; eating habits, in particular, consumption of hypercaloric diets, are relevant in its etiopathogenesis. On the other hand, foods can also modulate carcinogenesis: for example, proteins, which when hydrolyzed release peptides with biological activities, and legumes, especially, chickpea, represent a good source of hydrolysates. The objective of this work was to verify the inhibitory effect of chickpea hydrolyzed protein on azoxymethane (AOM)-induced carcinogenesis in mice fed a hypercaloric diet.

METHODS

We hydrolyzed chickpea protein by pepsin, pancreatin, and a combined pepsin-pancreatin system, to test its anticarcinogenic and hypercaloric activity in mice that had consumed a hypercaloric diet or a normal diet but were injected with azoxymethane (AOM).

RESULTS

A concentrate (70% proteins) was obtained from chickpea seeds (18.5% proteins), and extensive hydrolysates were obtained at 15 minutes, in all tested enzyme systems. The greatest activity was evidenced in the hydrolysates obtained with pepsin-pancreatin at 90 minutes. Animals that consumed the hypercaloric diet had a higher concentration of cholesterol and a higher atherogenic index, which were significantly reduced with the administration of chickpea protein hydrolysates with a dose-response effect (10, 20, or 30 mg/kg), whereas no effect was observed in animals that consumed the normal diet. In animals given AOM, aberrant crypts were observed, at a higher rate in animals that consumed the hypercaloric diet; with the consumption of hydrolysates by the animals that consumed either diet, the number of aberrant crypts was reduced with the 3 doses tested, and the effect was better in those animals fed the hypercaloric diet. The best effect in all tests was with 30 mg/kg body weight.

CONCLUSION

The consumption of chickpea protein hydrolysates might confer a protective effect against colon carcinogenesis.

Chemopreventive effects of some popular phytochemicals on human colon cancer: a review

The present review summarizes (1) the epidemiology and etiology of colon cancer, (2) generalized cancer chemoprotective mechanisms, and (3) the chemopreventive properties of some popular phytochemicals as well as some phytochemicals developed by our research group recently.

Antioxidant polyphenols in cancer treatment: Friend, foe or foil?

Cancer prevention can be probably obtained with easier, faster and less financial strains by pursuing educational programs aimed to induce changes in lifestyle, starting from dietary habits. In the past decades, observational and case-control studies tried to establish a functional relationship between cancer mortality and morbidity and diet. The field becomes even more intricate when scientists investigated which dietary components are responsible for the putative, protective effects of fruits and vegetables against cancer. A relevant part of the literature focused on the positive role of "antioxidant" compounds in foods, including polyphenols. The present review critically evaluate clinical and pre-clinical studies based on polyphenol administration, which contributed to support the concept, deeply rooted in the general population, that antioxidant polyphenols can fight cancer. The controversial and contradictory issues related to the pros and cons on the use of polyphenols against cancer reflect the confounding assumption that cancer treatment and cancer prevention may overlap. We conclude that a clear cut must be done between these two concepts and that the experimental approaches to investigate one or the other should be significantly different, starting from adequate and specifically selected cellular models.

Castanea sativa Mill. bark extract exhibits chemopreventive properties triggering extrinsic apoptotic pathway in Jurkat cells

Background

Chemoprevention represents the possibility to prevent, stop or reverse the cancerogenetic process. In this context the interest towards natural extracts and botanical drugs has constantly grown due to their phytochemical content. Castanea sativa Mill. (CSM) extracts showed to exert positive effect in the prevention/counteraction of chronic/degenerative diseases, therefore, we evaluated the potential chemopreventive effect of CSM bark extract.

Methods

Flow cytometry (FCM) analyses of Jurkat cells treated with CSM bark extract (0–500 μg·mL⁻¹) for 24–72 h allowed evaluating its cytotoxicity and ability to induce apoptosis through the intrinsic or extrinsic pathways. Moreover, to evaluate CSM bark extract selectivity towards cancer cells, its cytotoxic and pro-apoptotic effect was also evaluated in human peripheral blood lymphocytes (PBL).

Results

CSM bark extract induced apoptosis in Jurkat cells in a dose- and time- dependent manner activating the extrinsic pathways as evidenced by the increase of activated caspase-8 positive cells. Moreover, IC₅₀ calculated after 24 h treatment resulted 304 and 128 μg·mL⁻¹ in PBL and Jurkat cells respectively.

Conclusions

Our data suggest that CSM bark extract might be considered an interesting potential anti-cancer agent, since it induces apoptosis in cancer cells without appreciable cytotoxic effects on non-transformed cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-017-1756-6) contains supplementary material, which is available to authorized users.

Ellagic Acid Inhibits Bladder Cancer Invasiveness and In Vivo Tumor Growth

Ellagic acid (EA) is a polyphenolic compound that can be found as a naturally occurring hydrolysis product of ellagitannins in pomegranates, berries, grapes, green tea and nuts. Previous studies have reported the antitumor properties of EA mainly using in vitro models. No data are available about EA influence on bladder cancer cell invasion of the extracellular matrix triggered by vascular endothelial growth factor-A (VEGF-A), an angiogenic factor associated with disease progression and recurrence, and tumor growth in vivo. In this study, we have investigated EA activity against four different human bladder cancer cell lines (i.e., T24, UM-UC-3, 5637 and HT-1376) by in vitro proliferation tests (measuring metabolic and foci forming activity), invasion and chemotactic assays in response to VEGF-A and in vivo preclinical models in nude mice. Results indicate that EA exerts anti-proliferative effects as a single agent and enhances the antitumor activity of mitomycin C, which is commonly used for the treatment of bladder cancer. EA also inhibits tumor invasion and chemotaxis, specifically induced by VEGF-A, and reduces VEGFR-2 expression. Moreover, EA down-regulates the expression of programmed cell death ligand 1 (PD-L1), an immune checkpoint involved in immune escape. EA in vitro activity was confirmed by the results of in vivo studies showing a significant reduction of the growth rate, infiltrative behavior and tumor-associated angiogenesis of human bladder cancer xenografts. In conclusion, these results suggest that EA may have a potential role as an adjunct therapy for bladder cancer.

Inhibition of protein glycation, antioxidant and antiproliferative activities of Carpobrotus edulis extracts

Carpobrotus edulis is an important South African medicinal plants used as a food and therapeutic agent in traditional medicine. The aim of this study was to determine the phytochemical content, antioxidant, antiglycation and cytotoxic effect against Human Colon Cancer Cell Line (HCT-116) of aqueous and ethanol-water (1:1v/v) extracts of Carpobrotus edulis.The content of total phenolics and flavonoids in aqueous and ethanol-water extract were 151.99μg and 66.35μg gallic acid equivalents/mg of dry extract, and 38.84μg and 21.96μg quercetin/mg of dry extract, respectively. Furthermore, phenolic compositions analysis indicated the presence of seven majority compounds including sinapic acid, ferulic acid, luteolin7-o-glucoside, hyperoside, isoquercitrin, ellagic acid and isorhamnetin 3-O-rutinoside. The ethanol-water extract (100-1000μg/mL) showed better antioxidant activity than aqueous extract. Furthermore, Carpobrotus edulis extracts, especially ethanol-water extract significantly inhibited the formation of fluorescent advanced glycation end products, prevented oxidation-induced protein damage and exhibited a cytotoxic effect against HCT116 cells, with a significant decrease in cell viability after 24h of incubation. The results obtained suggest that the Carpobrotus edulis extracts could be used as an easily accessible source of natural antioxidants and as potential phytochemicals against protein glycation and colon cancer.

Protective effect of metformin in an aberrant crypt foci model induced by 1,2-dimethylhydrazine: Modulation of oxidative stress and inflammatory process

Colorectal Cancer (CRC) is the third most frequent type of cancer worldwide. In the past few years, studies have revealed a protective effect of metformin (MET-an anti-hyperglycemic drug, used to treat type 2 diabetes), against CRC. The protective effect of MET has been associated with AMPK activation (and mTOR inhibition), resulting in suppressed protein synthesis, and reduced cell proliferation in malignant transformed cells. To elucidate new mechanisms for the protective effect of metformin, we evaluated the oxidative stress and inflammatory process modulation, since these processes are strictly involved in colorectal carcinogenesis. The present study evaluated the protective effect of MET in a CRC model induced by 1,2-dimethylhydrazine (DMH) in Balb/c female mice. The simultaneous/continuous treatment (administration of MET and DMH simultaneously), revealed protective activity of MET, preventing the formation of aberrant crypt foci (ACF) in 71.4% at distal colon sections, and was able to restore basal labeling of apoptosis. Treatment with MET also reduced the inflammatory process induced by DMH, resulting in of the reduction of oxidative stress and nitric oxide related parameters. © 2016 Wiley Periodicals, Inc.

Comprehensive characterization of the effects of ellagic acid and urolithins on colorectal cancer and key-associated molecular hallmarks: MicroRNA cell specific induction of CDKN1A (p21) as a common mechanism involved

SCOPE

Ellagitannins, ellagic acid, and the colonic metabolites urolithins (Uros) exhibit anticancer effects against colon cells, but a comprehensive molecular analysis has not been done. Herein, we used a panel of cell lines to first time evaluate the antiproliferative properties and accompanying molecular responses of two ellagitannin metabolites mixtures mimicking the situation in vivo and of each individual metabolite.

METHODS AND RESULTS

We examined cell growth, cell cycle, apoptosis, and the expression of related genes and microRNAs (miRs) in a panel of nonmalignant and malignant colon cell lines. Regardless of the composition, the mixed metabolites similarly inhibited proliferation, induced cycle arrest, and apoptosis. All the metabolites contributed to these effects, but Uro-A, isourolithin A, Uro-C, and Uro-D were more potent than Uro-B and ellagic acid. Despite molecular differences between the cell lines, we discerned relevant changes in key cancer markers and corroborated the induction of CDKN1A (cyclin-dependent kinase inhibitor 1A gene (p21, Cip1); encoding p21) as a common step underlying the anticancer properties of Uros. Interestingly, cell-unique downregulation of miR-224 or upregulation of miR-215 was found associated with CDKN1A induction.

CONCLUSION

Physiologically relevant mixtures of Uros exert anticancer effects against colon cancer cells via a common CDKN1A upregulatory mechanism. Other associated molecular responses are however heterogeneous and mostly cell-specific.

The Effects of NDRG2 Overexpression on Cell Proliferation and Invasiveness of SW48 Colorectal Cancer Cell Line

BACKGROUND

Colorectal cancer (CRC) is one of the most common causes of cancer-related death in the world. The expression of N-myc downstream-regulated gene 2 (NDRG2) is down-regulated in CRC. The aim of this study was to investigate the effect of NDRG2 overexpression on cell proliferation and invasive potential of SW48 cells.

METHODS

SW48 cells were transfected with a plasmid overexpressing NDRG2. After stable transfection, the effect of NDRG2 overexpression on cell proliferation was evaluated by MTT assay. The effects of NDRG2 overexpression on cell migration, invasion and cell motility and matrix metalloproteinase 9 (MMP9) activities were also investigated using matrigel transwell assay, wound healing assay and gelatin zymography, respectively.

RESULTS

MTT assay showed that overexpression of NDRG2 caused attenuation of SW48 cell proliferation. Transwell and wound healing assay revealed that NDRG2 overexpression led to inhibition of migration, invasion, and motility of SW48 cells. The overexpression of NDRG2 also reduced the activity of secreted MMP-9.

CONCLUSIONS

The results of this study suggest that NDRG2 overexpression inhibits proliferation and invasive potential of SW48 cells, which likely occurs via suppression of MMP-9 activity.

The ellagic acid derivative 4,4'-di-O-methylellagic acid efficiently inhibits colon cancer cell growth through a mechanism involving WNT16

Ellagic acid (EA) and some derivatives have been reported to inhibit cancer cell proliferation, induce cell cycle arrest, and modulate some important cellular processes related to cancer. This study aimed to identify possible structure-activity relationships of EA and some in vivo derivatives in their antiproliferative effect on both human colon cancer and normal cells, and to compare this activity with that of other polyphenols. Our results showed that 4,4'-di-O-methylellagic acid (4,4'-DiOMEA) was the most effective compound in the inhibition of colon cancer cell proliferation. 4,4'-DiOMEA was 13-fold more effective than other compounds of the same family. In addition, 4,4'-DiOMEA was very active against colon cancer cells resistant to the chemotherapeutic agent 5-fluoracil, whereas no effect was observed in nonmalignant colon cells. Moreover, no correlation between antiproliferative and antioxidant activities was found, further supporting that structure differences might result in dissimilar molecular targets involved in their differential effects. Finally, microarray analysis revealed that 4,4'-DiOMEA modulated Wnt signaling, which might be involved in the potential antitumor action of this compound. Our results suggest that structural-activity differences between EA and 4,4'-DiOMEA might constitute the basis for a new strategy in anticancer drug discovery based on these chemical modifications.

Ellagic acid inhibits proliferation and induced apoptosis via the Akt signaling pathway in HCT-15 colon adenocarcinoma cells

Chemoprevention is regarded as one of the most promising and realistic approaches in the prevention of human cancer. Ellagic acid (EA) has been known for its chemopreventive activity against various cancers and numerous investigations have shown its apoptotic activity both in vivo and in vitro. The present study was focused to elucidate the anticancerous effect and the mode of action of EA against HCT-15 colon adenocarcinoma cells. Cell viability was assessed using trypan blue assay at different concentrations. EA also promoted cell cycle arrest substantially at G2/M phase in HCT-15 cells. The activities of alkaline phosphatase and lactate dehydrogenase were decreased upon EA treatment, which shows the antiproliferative and the cytotoxic effects, respectively. The production of reactive oxygen intermediates, which were examined by 2,7-dichlorodihydrofluorescein diacetate (H2DCF-DA), increased with time, after treatment with EA. In further studies, EA inhibited proliferation-associated markers proliferating cell nuclear antigen and cyclin D1. The induction of apoptosis was accompanied by a strong inactivation of phosphatidylinositol 3-kinase (PI3K)/Akt pathway by EA. The expression of PI3K and pAkt was down-regulated in EA-treated cells, compared to normal cells. Further, EA promoted the expression of Bax, caspase-3, and cytochrome c, and suppression of Bcl-2 activity in HCT-15 cells that was determined by western blot analysis. Increased annexin V apoptotic cells and DNA fragmentation also accompanied EA-induced apoptosis. In conclusion, EA increased the production of ROS, decreased cell proliferation, and induced apoptosis in HCT-15 cells, and thus can be used as an agent against colon cancer.

Effect of the French oak wood extract Robuvit on markers of oxidative stress and activity of antioxidant enzymes in healthy volunteers: a pilot study

We examined in vitro antioxidant capacity of polyphenolic extract obtained from the wood of oak Quercus robur (QR), Robuvit, using TEAC (Trolox equivalent antioxidant capacity) method and the effect of its intake on markers of oxidative stress, activity of antioxidant enzymes, and total antioxidant capacity in plasma of 20 healthy volunteers. Markers of oxidative damage to proteins, DNA, and lipids and activities of Cu/Zn-superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were determined in the erythrocytes. We have found an in vitro antioxidant capacity of Robuvit of 6.37 micromole Trolox equivalent/mg of Robuvit. One month intake of Robuvit in daily dose of 300 mg has significantly decreased the serum level of advanced oxidation protein products (AOPP) and lipid peroxides (LP). Significantly increased activities of SOD and CAT as well as total antioxidant capacity of plasma after one month intake of Robuvit have been shown. In conclusion, we have demonstrated for the first time that the intake of Robuvit is associated with decrease of markers of oxidative stress and increase of activity of antioxidant enzymes and total antioxidant capacity of plasma in vivo.