The anticancer effects of resveratrol: modulation of transcription factors

Methylation Landscape of Human Breast Cancer Cells in Response to Dietary Compound Resveratrol

Aberrant DNA methylation is a frequent epigenetic alteration in cancer cells that has emerged as a pivotal mechanism for tumorigenesis. Accordingly, novel therapies targeting the epigenome are being explored with the aim to restore normal DNA methylation patterns on oncogenes and tumor suppressor genes. A limited number of studies indicate that dietary compound resveratrol modulates DNA methylation of several cancer-related genes; however a complete view of changes in methylome by resveratrol has not been reported yet. In this study we performed a genome-wide survey of DNA methylation signatures in triple negative breast cancer cells exposed to resveratrol. Our data showed that resveratrol treatment for 24 h and 48 h decreased gene promoter hypermethylation and increased DNA hypomethylation. Of 2476 hypermethylated genes in control cells, 1,459 and 1,547 were differentially hypomethylated after 24 h and 48 h, respectively. Remarkably, resveratrol did not induce widespread non-specific DNA hyper- or hypomethylation as changes in methylation were found in only 12.5% of 27,728 CpG loci. Moreover, resveratrol restores the hypomethylated and hypermethylated status of key tumor suppressor genes and oncogenes, respectively. Importantly, the integrative analysis of methylome and transcriptome profiles in response to resveratrol showed that methylation alterations were concordant with changes in mRNA expression. Our findings reveal for the first time the impact of resveratrol on the methylome of breast cancer cells and identify novel potential targets for epigenetic therapy. We propose that resveratrol may be considered as a dietary epidrug as it may exert its anti-tumor activities by modifying the methylation status of cancer -related genes which deserves further in vivo characterization.

Differential responses of Trans-Resveratrol on proliferation of neural progenitor cells and aged rat hippocampal neurogenesis

The plethora of literature has supported the potential benefits of Resveratrol (RV) as a life-extending as well as an anticancer compound. However, these two functional discrepancies resulted at different concentration ranges. Likewise, the role of Resveratrol on adult neurogenesis still remains controversial and less understood despite its well documented health benefits. To gather insight into the biological effects of RV on neurogenesis, we evaluated the possible effects of the compound on the proliferation and survival of neural progenitor cells (NPCs) in culture, and in the hippocampus of aged rats. Resveratrol exerted biphasic effects on NPCs; low concentrations (10 μM) stimulated cell proliferation mediated by increased phosphorylation of extracellular signal-regulated kinases (ERKs) and p38 kinases, whereas high concentrations (>20 μM) exhibited inhibitory effects. Administration of Resveratrol (20 mg/kg body weight) to adult rats significantly increased the number of newly generated cells in the hippocampus, with upregulation of p-CREB and SIRT1 proteins implicated in neuronal survival and lifespan extension respectively. We have successfully demonstrated that Resveratrol exhibits dose dependent discrepancies and at a lower concentration can have a positive impact on the proliferation, survival of NPCs and aged rat hippocampal neurogenesis implicating its potential as a candidate for restorative therapies against age related disorders.

Enhanced inhibition of clonogenic survival of human medulloblastoma cells by multimodal treatment with ionizing irradiation, epigenetic modifiers, and differentiation-inducing drugs

Background

Medulloblastoma (MB) is the most common pediatric brain tumor. Current treatment regimes consisting of primary surgery followed by radio- and chemotherapy, achieve 5-year overall survival rates of only about 60 %. Therapy-induced endocrine and neurocognitive deficits are common late adverse effects. Thus, improved antitumor strategies are urgently needed. In this study, we combined irradiation (IR) together with epigenetic modifiers and differentiation inducers in a multimodal approach to enhance the efficiency of tumor therapy in MB and also assessed possible late adverse effects on neurogenesis.

Methods

In three human MB cell lines (DAOY, MEB-Med8a, D283-Med) short-time survival (trypan blue exclusion assay), apoptosis, autophagy, cell cycle distribution, formation of gH2AX foci, and long-term reproductive survival (clonogenic assay) were analyzed after treatment with 5-aza-2′-deoxycytidine (5-azadC), valproic acid (VPA), suberanilohydroxamic acid (SAHA), abacavir (ABC), all-trans retinoic acid (ATRA) and resveratrol (RES) alone or combined with 5-aza-dC and/or IR. Effects of combinatorial treatments on neurogenesis were evaluated in cultured murine hippocampal slices from transgenic nestin-CFPnuc C57BL/J6 mice. Life imaging of nestin-positive neural stem cells was conducted at distinct time points for up to 28 days after treatment start.

Results

All tested drugs showed a radiosynergistic action on overall clonogenic survival at least in two-outof-three MB cell lines. This effect was pronounced in multimodal treatments combining IR, 5-aza-dC and a second drug. Hereby, ABC and RES induced the strongest reduction of clongenic survival in all three MB cell lines and led to the induction of apoptosis (RES, ABC) and/or autophagy (ABC). Additionally, 5-aza-dC, RES, and ABC increased the S phase cell fraction and induced the formation of gH2AX foci at least in oneout-of-three cell lines. Thereby, the multimodal treatment with 5-aza-dC, IR, and RES or ABC did not change the number of normal neural progenitor cells in murine slice cultures.

Conclusion

In conclusion, the radiosensitizing capacities of epigenetic and differentiation-inducing drugs presented here suggest that their adjuvant administration might improve MB therapy. Thereby, the combination of 5-aza-dC/IR with ABC and RES seemed to be the most promising to enhance tumor control without affecting the normal neural precursor cells.

Resveratrol Treatment Inhibits Proliferation of and Induces Apoptosis in Human Colon Cancer Cells

Background

Resveratrol, a natural isolate from plant sources, has a long and important history in traditional Chinese medicine. In the present study we investigated the effect of resveratrol on human colon cancer cell lines.

Material/Methods

We used the Cell Counting kit-8 (CCK-8) for determination of colon cancer cell viability. Apoptosis induction was analyzed using the DeadEnd™ Colorimetric TUNEL System (Promega, Madison, WI, USA). The siRNA Transfection Reagent kit (Santa Cruz Biotechnology, Inc.) was used for the administration of COX-2 silencer RNA (siRNA) into the colon cancer cells. Primer Express^® software for Real-Time PCR ver. 3.0 (Applied Biosystems, Foster City, CA, USA) was used to prepare the primers for RT-PCR.

Results

The results revealed that exposure of colon cancer cells to resveratrol inhibited cell viability. Resveratrol exhibited a significant inhibitory effect on cell viability at 30 μM concentration after 48 h of exposure. We observed that 30-μM doses of resveratrol for 72 h led to 18, 29, and 34% reduction in the viability of HCA-17, SW480, and HT29 cells, respectively. It also significantly induced apoptosis in both of the tested carcinoma cell lines. The population of apoptotic cells in HCA-17 and SW480 cell lines after 48 h of resveratrol treatment was 59.8±4 and 67.2±4%, respectively, compared to 2.3±1% in the control cells. The colon cancer cells exposed to resveratrol showed significantly lower cyclooxygenase-2 and prostaglandin receptor expression. Treatment of colon cancer cells with the inhibitor of cyclooxygenase-2, indomethacin, and administration of silencer RNA for cyclooxygenase-2 also produced similar results.

Conclusions

These findings suggest that resveratrol treatment can be a promising strategy for the treatment of colon cancer.

A Nutritional Approach to the Prevention of Cancer: from Assessment to Personalized Intervention

Among lifestyle factors, nutrition is one of the most important determinants of health, and represents a pivotal element of cancer risk. Nonetheless, epidemiological evidences of the relationship between several cancers and specific foods and nutrients is still inadequate, and solid conclusions are missing. Indeed, caloric restriction without malnutrition is associated to cancer prevention. Food may be also the primary route of exposure to contaminants such as metals, persistent organic pollutants, and pesticides. Exposuredisease associations and the interplay with genetic susceptibility requires further studies on genetic variation, environment, lifestyle, and chronic disease in order to eliminate and reduce associated health risks, thus contributing to improve health outcomes for the population. A primary nutritional approach for Active and Healthy Ageing (AHA) has been developed by the Nutrition group of the European Innovation Partnership (EIP) on AHA. The working group on lifestyles of the Italian Ministry of Health has developed a comprehensive approach to adequate nutrition using a consensus methodology to collect and integrate the available evidences from the literature and from the Italian experiences at the regional level, to raise the interest of other experts and relevant stakeholders to outline and scale-up joint strategies for a primary nutritional approach to cancer prevention.

Role of phytochemicals in the inhibition of epithelial–mesenchymal transition in cancer metastasis

Epithelial–mesenchymal transition (EMT) development is controlled by several signaling pathways including Hedgehog, Wnt, fibroblast growth factors (FGF), hepatocyte growth factor/scatter factor (HGF),etc. Phytochemicals is very promising therapeutic candidate that inhibit the progression of EMT by inhibiting the signaling pathways.

Resveratrol exerts anti-obesity effects in high-fat diet obese mice and displays differential dosage effects on cytotoxicity, differentiation, and lipolysis in 3T3-L1 cells

Studies on resveratrol in a wide range of concentrations on obese mice and adipose cells are necessary to comprehend its range of diverse and contradictory effects. In this study, we examined the anti-obesity effects of resveratrol on high-fat diet (HFD)-induced obese mice at dosages ranging from 1 to 30 mg/kg treatment for 10 wk. We also evaluated the effects of resveratrol on cytotoxicity, proliferation, adipogenic differentiation, and lipolysis of 3T3-L1 cells at concentrations ranging from 0.03 to 100 μM. In HFD obese mice, resveratrol treatment for 10 wk without decreased calories intake significantly attenuated HFD-induced weight gain in a dose-dependent manner. Resveratrol treatment also protected against HFD-induced lipid deposition in adipose tissues and liver. In cultured 3T3-L1 preadipocytes, high dosage (10 to 100 μM) resveratrol treatment produced cytotoxicity in both preadipocytes and mature adipocytes. In contrast, low concentration resveratrol treatment (1 to 10 μM) significantly inhibited the capacity of 3T3-L1 cells differentiated into mature adipocytes. Low dose resveratrol treatment also downregulated peroxisome proliferator-activated receptor gamma (PPARγ) and perilipin protein expressions in differentiated adipocytes. Additionally, tumor necrosis factor alpha (TNFα)-induced lipolysis was inhibited by low concentration resveratrol treatment in mature adipocytes. At concentrations of 10-100 μM, resveratrol exerted cytotoxicity. In contrast, at concentrations of 1-10 μM resveratrol inhibited adipogenic differentiation in preadipocytes and suppressed lipolysis in mature adipocytes. Our results suggest that resveratrol possessed anti-obesity effects by induction of cytotoxicity at high dosage and that it influences preadipocyte differentiation and mature adipocyte lipolysis at low concentration.

Resveratrol alleviate hypoxic pulmonary hypertension via anti-inflammation and anti-oxidant pathways in rats

Resveratrol, a plant-derived polyphenolic compound and a phytoestrogen, was shown to possess multiple protective effects including anti-inflammatory response and anti-oxidative stress. Hypoxic pulmonary hypertension (HPH) is a progressive disease characterized by sustained vascular resistance and marked pulmonary vascular remodeling. The exact mechanisms of HPH are still unclear, but inflammatory response and oxidative stress was demonstrated to participate in the progression of HPH. The present study was designed to investigate the effects of resveratrol on HPH development. Sprague-Dawley rats were challenged by hypoxia exposure for 28 days to mimic hypoxic pulmonary hypertension along with treating resveratrol (40 mg/kg/day). Hemodynamic and pulmonary pathomorphology data were then obtained, and the anti-proliferation effect of resveratrol was determined by in vitro assays. The anti-inflammation and anti-oxidative effects of resveratrol were investigated in vivo and in vitro. The present study showed that resveratrol treatment alleviated right ventricular systolic pressure and pulmonary arterial remodeling induced by hypoxia. In vitro experiments showed that resveratrol notably inhibited proliferation of pulmonary arterial smooth muscle cells in an ER-independent manner. Data showed that resveratrol administration inhibited HIF-1 α expression in vivo and in vitro, suppressed inflammatory cells infiltration around the pulmonary arteries, and decreased ROS production induced by hypoxia in PAMSCs. The inflammatory cytokines' mRNA levels of tumor necrosis factor α, interleukin 6, and interleukin 1β were all suppressed by resveratrol treatment. The in vitro assays showed that resveratrol inhibited the expression of HIF-1 α via suppressing the MAPK/ERK1 and PI3K/AKT pathways. The antioxidant axis of Nuclear factor erythroid-2 related factor 2/ Thioredoxin 1 (Nrf-2/Trx-1) was up-regulated both in lung tissues and in cultured PASMCs. In general, the current study demonstrated that resveratrol may prevent pulmonary hypertension through its anti-proliferation, anti-inflammation and antioxidant effects. Hence, the present data may offer novel targets and promising pharmacological perspective for treating hypoxic pulmonary hypertension.

Resveratrol overcomes gefitinib resistance by increasing the intracellular gefitinib concentration and triggering apoptosis, autophagy and senescence in PC9/G NSCLC cells

Gefitinib (Gef) provides clinical benefits to non-small cell lung cancer (NSCLC) patients with activating EGFR mutations. However, acquired resistance (AR) is a major obstacle to effective Gef therapy. This study demonstrated that resveratrol (Res) could synergize with Gef to inhibit the proliferation of Gef-resistant NSCLC cells. The underlying mechanisms of synergism were investigated, and the results showed that cotreatment with Gef and Res could inhibit EGFR phosphorylation by increasing intracellular Gef accumulation through the impairment of Gef elimination from PC9/G cells. Consistently, CYP1A1 and ABCG2 expression were inhibited. Meanwhile, the cotreatment significantly induced cell apoptosis, autophagy, cell cycle arrest and senescence accompanied by increased expression of cleaved caspase-3, LC3B-II, p53 and p21. Further studies revealed that autophagy inhibition enhanced apoptosis and abrogated senescence while apoptosis inhibition had no notable effect on cell autophagy and senescence during cotreatment with Gef and Res. These results indicated that in addition to apoptosis, senescence promoted by autophagy contributes to the antiproliferation effect of combined Gef and Res on PC9/G cells. In conclusion, combined treatment with Gef and Res may represent a rational strategy to overcome AR in NSCLC cells.

Antioxidant Phytochemicals for the Prevention and Treatment of Chronic Diseases

Overproduction of oxidants (reactive oxygen species and reactive nitrogen species) in the human body is responsible for the pathogenesis of some diseases. The scavenging of these oxidants is thought to be an effective measure to depress the level of oxidative stress of organisms. It has been reported that intake of vegetables and fruits is inversely associated with the risk of many chronic diseases, and antioxidant phytochemicals in vegetables and fruits are considered to be responsible for these health benefits. Antioxidant phytochemicals can be found in many foods and medicinal plants, and play an important role in the prevention and treatment of chronic diseases caused by oxidative stress. They often possess strong antioxidant and free radical scavenging abilities, as well as anti-inflammatory action, which are also the basis of other bioactivities and health benefits, such as anticancer, anti-aging, and protective action for cardiovascular diseases, diabetes mellitus, obesity and neurodegenerative diseases. This review summarizes recent progress on the health benefits of antioxidant phytochemicals, and discusses their potential mechanisms in the prevention and treatment of chronic diseases.

In vitro antitumor effects of two novel oligostilbenes, cis- and trans-suffruticosol D, isolated from Paeonia suffruticosa seeds

Naturally derived stilbenes have been shown to elicit cytotoxic, anti-steroidal, anti-mutagenic, anti-oxidative, anti-inflammatory, and antitumor bioactivities. Previous phytochemical studies revealed that the seeds of Paeonia suffruticosa are rich in natural stilbenes. In this study the antitumor effects and mechanism of action of the oligostilbene isomers, cis- and trans-suffruticosol D, isolated from the seeds of P. suffruticosa were examined. cis- and trans-suffruticosol D exhibited remarkable cytotoxicity against the human cancer cell lines A549 (lung), BT20 (breast), MCF-7 (breast), and U2OS (osteosarcoma), but showed significantly less toxicity to the normal human cell lines HMEC (breast) and HPL1A (lung). We also demonstrated that cis- and trans-suffruticosol D exerted their antitumor effects by provoking oxidative stress, stimulating apoptosis, decreasing the mitochondrial membrane potential, inhibiting cell motility, and blocking the NF-κB pathway in human lung cancer cells. In addition, we evaluated their respective bioefficacy and found that trans-suffruticosol D is more potent than cis-suffruticosol D. Collectively, our results suggest that cis- and trans-suffruticosol D could be promising chemotherapeutic agents against cancer.

Can the chemotherapeutic agents perform anticancer activity through miRNA expression regulation? Proposing a new hypothesis [corrected]

In the recent advancement of cancer therapy, mortality of the immortal cancer cells begins to decline, and it shows great promise for the chemotherapy regimen supported by targeted therapy. In this post-genomic era boosted by the discovery of microRNA (miRNA), it has been understood that miRNA regulates gene expression at the post-transcriptional level. On the other hand, some studies have also indicated that miRNA expression level has changed during the treatment of chemotherapy. Data based on various previous studies, we propose that the chemotherapeutic agents modulate miRNA expression that might perform anticancerous activities through cellular changes such as DNA repair, cell cycle arrest, or apoptosis.

The effect of resveratrol on pharmacokinetics of aripiprazole in vivo and in vitro

1. The objective of this study were to investigate the effect of orally administered resveratrol on the pharmacokinetics of aripiprazole (APZ) in rat, and the inhibitory effects of resveratrol on APZ dehydrogenation activity in liver microsomes and human cytochrome P450 3A4 and 2D6. 2. Twenty-five healthy male Sprague-Dawley rats were randomly divided into five groups: A (control group), B (multiple dose of 200 mg/kg resveratrol), C (multiple dose of 100 mg/kg resveratrol), D (a single dose of 200 mg/kg resveratrol) and E (a single dose of 100 mg/kg resveratrol). A single dose of 3 mg/kg APZ administered orally 30 min after administration of resveratrol. In addition, CYP2D6*1, CYP3A4*1, human and rat liver microsomes were performed to determine the effect of resveratrol on the metabolism of APZ in vitro. 3. The multiple dose of 200 or 100 mg/kg resveratrol significantly increased the AUC and Cmax of APZ. The resveratrol also obviously decreased the CL, but without any significant difference on t1/2 in vivo. On the other hand, resveratrol showed inhibitory effect on CYP3A4*1, CYP2D6*1, human and rat microsomes, the IC50 of resveratrol was 6.771, 87.87, 45.11 and 35.59 μmol l(-1), respectively. 4. Those results indicated more attention should be paid when APZ was administrated combined with resveratrol.

Non-Nutrient, Naturally Occurring Phenolic Compounds with Antioxidant Activity for the Prevention and Treatment of Periodontal Diseases

One of the main factors able to explain the pathophysiological mechanism of inflammatory conditions that occur in periodontal disease is oxidative stress. Given the emerging understanding of this relationship, host-modulatory therapies using antioxidants could be interesting to prevent or slow the breakdown of soft and hard periodontal tissues. In this context, non-nutrient phenolic compounds of various foods and plants have received considerable attention in the last decade. Here, studies focusing on the relationship between different compounds of this type with periodontal disease have been collected. Among them, thymoquinone, coenzyme Q (CoQ), mangiferin, resveratrol, verbascoside and some flavonoids have shown to prevent or ameliorate periodontal tissues damage in animal models. However evidence regarding this effect in humans is poor and only limited to topical treatments with CoQ and catechins. Along with animal experiments, in vitro studies indicate that possible mechanisms by which these compounds might exert their protective effects include antioxidative properties, oxygen and nitrogen scavenging abilities, and also inhibitory effects on cell signaling cascades related to inflammatory processes which have an effect on RNS or ROS production as well as on antioxidant defense systems.

Resveratrol ameliorates renal damage, increases expression of heme oxygenase-1, and has anti-complement, anti-oxidative, and anti-apoptotic effects in a murine model of membranous nephropathy

Background

Idiopathic membranous nephropathy (MN) is an autoimmune-mediated glomerulonephritis and a common cause of nephrotic syndrome in adults. There are limited available treatments for MN. We assessed the efficacy of resveratrol (RSV) therapy for treatment of MN in a murine model of this disease.

Methods

Murine MN was experimentally induced by daily subcutaneous administration of cationic bovine serum albumin, with phosphate-buffered saline used in control mice. MN mice were untreated or given RSV. Disease severity and pathogenesis was assessed by determination of metabolic and histopathology profiles, lymphocyte subsets, immunoglobulin production, oxidative stress, apoptosis, and production of heme oxygenase-1 (HO1).

Results

MN mice given RSV had significantly reduced proteinuria and a marked amelioration of glomerular lesions. RSV also significantly attenuated immunofluorescent staining of C3, although there were no changes of serum immunoglobulin levels or immunocomplex deposition in the kidneys. RSV treatment of MN mice also reduced the production of reactive oxygen species (ROS), reduced cell apoptosis, and upregulated heme oxygenase 1 (HO1). Inhibition of HO1 with tin protoporphyrin IX partially reversed the renoprotective effects of RSV. The HO1 induced by RSV maybe via Nrf2 signaling.

Conclusion

Our results show that RSV increased the expression of HO1 and ameliorated the effects of membranous nephropathy in a mouse model due to its anti-complement, anti-oxidative, and anti-apoptotic effects. RSV appears to have potential as a treatment for MN.

Targeting HER2 Positive Breast Cancer with Chemopreventive Agents

Human epidermal growth factor receptor 2-positive (HER2+) breast cancer is a subtype of breast cancer that is exhibited in approximately 20-30% of breast cancer cases. The overexpression of HER2 is typically associated with a more aggressive disease and poor prognosis. Currently, the therapeutic drugs trastuzumab and lapatinib are the most commonly used to combat HER2+ breast cancer. However, tumors can develop resistance to these drugs. A better understanding of the mechanism of how HER2+ breast cancer works will help aid the development for new therapeutic approaches which more closely target the source of the signaling dysfunction. This review summarizes four major points in the context of HER2 over-expressing breast cancer (i) HER2 as a molecular target in breast cancer therapy, (ii) current treatment options as well as ongoing clinical studies, (iii) animal and cellular models for the study of HER2 over-expressing breast cancer, and (iv) future therapies and chemopreventive agents used to target HER2+ breast cancer.

The Role of Nutraceuticals in Pancreatic Cancer Prevention and Therapy: Targeting Cellular Signaling, MicroRNAs, and Epigenome

Pancreatic cancer is one of the most aggressive malignancies in US adults. Experimental studies have found that antioxidant nutrients could reduce oxidative DNA damage, suggesting that these antioxidants may protect against pancreatic carcinogenesis. Several epidemiologic studies showed that dietary intake of antioxidants was inversely associated with the risk for pancreatic cancer, demonstrating the inhibitory effects of antioxidants on pancreatic carcinogenesis. Moreover, nutraceuticals, the anticancer agents from diet or natural plants, have been found to inhibit the development and progression of pancreatic cancer through the regulation of cellular signaling pathways. Importantly, nutraceuticals also up-regulate the expression of tumor-suppressive microRNAs (miRNAs) and down-regulate the expression of oncogenic miRNAs, leading to the inhibition of pancreatic cancer cell growth and pancreatic cancer stem cell self-renewal through modulation of cellular signaling network. Furthermore, nutraceuticals also regulate epigenetically deregulated DNAs and miRNAs, leading to the normalization of altered cellular signaling in pancreatic cancer cells. Therefore, nutraceuticals could have much broader use in the prevention and/or treatment of pancreatic cancer in combination with conventional chemotherapeutics. However, more in vitro mechanistic experiments, in vivo animal studies, and clinical trials are needed to realize the true value of nutraceuticals in the prevention and/or treatment of pancreatic cancer.

Resveratrol inhibits oesophageal adenocarcinoma cell proliferation via AMP-activated protein kinase signaling

Resveratrol has been examined in several model systems for potential effects against cancer. Adenosine monophosphate-activated protein kinase (AMPK) is reported to suppress proliferation in most eukaryocyte cells. Whether resveratrol via AMPK inhibits proliferation of oesophageal adenocarcinoma cells (OAC) is unknown. The aim of this study was to determine the roles of AMPK in the protective effects of resveratrol in OAC proliferation and to elucidate the underlying mechanisms. Treatment of cultured OAC derived from human subjects or cell lines with resveratrol resulted in decreased cell proliferation. Further, inhibition of AMPK by pharmacological reagent or genetical approach abolished resveratrol-suppressed OAC proliferation, reduced the level of p27Kip1, a cyclin-dependent kinase inhibitor, and increased the levels of S-phase kinase-associated protein 2 (Skp2) of p27Kip1-E3 ubiquitin ligase and 26S proteasome activity reduced by resveratrol. Furthermore, gene silencing of p27Kip1 reversed resveratrol-suppressed OAC proliferation. In conclusion, these findings indicate that resveratrol inhibits Skp2-mediated ubiquitylation and 26S proteasome-dependent degradation of p27Kip1 via AMPK activation to suppress OAC proliferation.

Biocatalysis and biotransformation of resveratrol in microorganisms

Resveratrol, a major stilbene phytoalexin, is a valuable polyphenol that has been recognized for its benefits to human health. Resveratrol has antioxidant and antitumor effects and promotes longevity. It is used in medicine, health care products, cosmetics, and other industries. Therefore, a sustainable source for resveratrol production is required. This review describes the metabolic engineering of microorganisms, the biotransformation and biosynthesis of endophytes and the oxidation or degradation of resveratrol. We compare various available methods for resveratrol production, and summarize the practical challenges facing the microbial production of resveratrol. The future research direction for resveratrol is also discussed.

Regulation of microRNAs by natural agents: new strategies in cancer therapies

MicroRNAs (miRNAs) are short noncoding RNA which regulate gene expression by messenger RNA (mRNA) degradation or translation repression. The plethora of published reports in recent years demonstrated that they play fundamental roles in many biological processes, such as carcinogenesis, angiogenesis, programmed cell death, cell proliferation, invasion, migration, and differentiation by acting as tumour suppressor or oncogene, and aberrations in their expressions have been linked to onset and progression of various cancers. Furthermore, each miRNA is capable of regulating the expression of many genes, allowing them to simultaneously regulate multiple cellular signalling pathways. Hence, miRNAs have the potential to be used as biomarkers for cancer diagnosis and prognosis as well as therapeutic targets. Recent studies have shown that natural agents such as curcumin, resveratrol, genistein, epigallocatechin-3-gallate, indole-3-carbinol, and 3,3′-diindolylmethane exert their antiproliferative and/or proapoptotic effects through the regulation of one or more miRNAs. Therefore, this review will look at the regulation of miRNAs by natural agents as a means to potentially enhance the efficacy of conventional chemotherapy through combinatorial therapies. It is hoped that this would provide new strategies in cancer therapies to improve overall response and survival outcome in cancer patients.

The effect of resveratrol and its methylthio-derivatives on EGFR and Stat3 activation in human HaCaT and A431 cells

Epidermal growth factor receptor (EGFR) interacting with Stat3 is considered to be an attractive therapeutic target. In the current study, we investigated the effect of resveratrol and its two 4′-methylthio-trans-stilbene derivatives (3-M-4′-MTS; S2) (3,5-DM-4″-MTS; S5) on EGFR and Stat3 activation in human immortalized HaCaT keratinocytes and epidermoid carcinoma A431 cells. In the HaCaT cells both derivatives, similarly as resveratrol, decreased the total level of the EGFR receptor. In the A431 cells, resveratrol in the higher dose significantly (p < 0.05) reduced Y1173 and Y1068 EGFR residue phosphorylation, while S2 affected only the phosphorylation of the Y1068 residue. In this cell line, resveratrol in both tested doses and the S2 derivative in the lower concentration significantly diminished Stat3 binding capacity to the DNA consensus site. The effect of the tested compounds on Stat3 activation in HaCaT cells was only slightly affected. These results indicate that methylthiostilbenes are not more potent modulators of the EGFR/Stat3 complex than resveratrol and that introducing an additional methoxy group makes them less effective.

A novel anti‑cancer effect of resveratrol: reversal of epithelial‑mesenchymal transition in prostate cancer cells

Carcinoma progression is associated with the loss of epithelial features and the acquisition of a mesenchymal phenotype, a process known as epithelial-mesenchymal transition (EMT). Resveratrol, a natural polyphenolic compound found in grapes, berries and peanuts, has a wide range of pharmacological properties, including anti-tumor metastasis properties. The underlying mechanism through which resveratrol inhibits metastasis of prostate cancer (PCa) is not yet fully understood; however, it is thought to be associated with the disruption of EMT. In the present study, lipopolysaccharide (LPS) was used to trigger EMT in PC-3 and LNCaP PCa cell lines, and the cell lines were subsequently treated with resveratrol. The results demonstrated that exposure of PC-3 and LNCaP cells to LPS resulted in morphological alterations characteristic of EMT, as well as an increase in the expression of the mesenchymal marker vimentin and a decrease in the expression of E-cadherin. In addition, LPS exposure resulted in an increase in cell motility, along with an upregulation of the transcription factor glioma-associated oncogene homolog 1 (Gli1). However, treatment with resveratrol inhibited LPS-induced morphological changes, decreased the expression of LPS-induced markers of EMT and inhibited the expression of Gli1, resulting in the inhibition of in vitro cell motility and invasiveness. These results provide a novel perspective for the anti-invasion mechanism of resveratrol, suggesting that the effect is in part due to its ability to inhibit the EMT process through the Hedgehog signaling pathway.

DMU-212 inhibits tumor growth in xenograft model of human ovarian cancer

DMU-212 has been shown to evoke a mitochondrial apoptotic pathway in transformed fibroblasts and breast cancer. However, recently published data indicated the ability of DMU-212 to evoke apoptosis in both mitochondria- and receptor-mediated manner in two ovarian cancer cell lines, namely A-2780 and SKOV-3, which showed varied sensitivity to the compound tested. The pronounced cytotoxic effects of DMU-212 observed in A-2780 cells were related to the execution of extracellular apoptosis pathway and cell cycle arrest in G2/M phase. In view of the great anticancer potential of DMU-212 against A-2780 cell line, the aim of the current study was to assess antiproliferative activity of DMU-212 in xenograft model of ovarian cancer. To evaluate in vitro metabolic properties of cells that were to be injected into SCID mice, uptake and decline of DMU-212 in A-2780 ovarian cancer cell line was investigated. It was found that the concentration of the test compound in A-2780 cells was growing within first eight hours, and then the gradual decline was observed. A-2780 cells stably transfected with pcDNA3.1/Zeo(-)-Luc vector were subcutaneously inoculated into the right flanks of SCID mice. After seven days of the treatment with DMU-212 (50mg/kg b.w), tumor growth appeared to be suppressed in the animals treated with the compound tested. At day 14 of the experiment, tumor burden in mice treated with DMU-212 was significantly lower, as compared to untreated controls. Our findings suggest that DMU-212 might be considered as a potential anticancer agent used in ovarian cancer therapy.

Resveratrol differentially regulates NAMPT and SIRT1 in Hepatocarcinoma cells and primary human hepatocytes

Resveratrol is reported to possess chemotherapeutic properties in several cancers. In this study, we wanted to investigate the molecular mechanisms of resveratrol-induced cell cycle arrest and apoptosis as well as the impact of resveratrol on NAMPT and SIRT1 protein function and asked whether there are differences in hepatocarcinoma cells (HepG2, Hep3B cells) and non-cancerous primary human hepatocytes. We found a lower basal NAMPT mRNA and protein expression in hepatocarcinoma cells compared to primary hepatocytes. In contrast, SIRT1 was significantly higher expressed in hepatocarcinoma cells than in primary hepatocytes. Resveratrol induced cell cycle arrest in the S- and G2/M- phase and apoptosis was mediated by activation of p53 and caspase-3 in HepG2 cells. In contrast to primary hepatocytes, resveratrol treated HepG2 cells showed a reduction of NAMPT enzymatic activity and increased p53 acetylation (K382). Resveratrol induced NAMPT release from HepG2 cells which was associated with increased NAMPT mRNA expression. This effect was absent in primary hepatocytes where resveratrol was shown to function as NAMPT and SIRT1 activator. SIRT1 inhibition by EX527 resembled resveratrol effects on HepG2 cells. Furthermore, a SIRT1 overexpression significantly decreased both p53 hyperacetylation and resveratrol-induced NAMPT release as well as S-phase arrest in HepG2 cells. We could show that NAMPT and SIRT1 are differentially regulated by resveratrol in hepatocarcinoma cells and primary hepatocytes and that resveratrol did not act as a SIRT1 activator in hepatocarcinoma cells.

3,4,5,4'-trans-tetramethoxystilbene (DMU-212) modulates the activation of NF-κB, AP-1, and STAT3 transcription factors in rat liver carcinogenesis induced by initiation-promotion regimen

It has been reported that methylated analog of resveratrol, 3,4,5,4′-trans-tetramethoxystilbene (DMU-212), demonstrates strong antiproliferative, and proapoptotic activity. The aim of this study was to evaluate the effect of DMU-212 on the activation of nuclear factor-κB (NF-κB), activator protein-1 (AP-1), and signal transducer and activator of transcription 3 (STAT3) transcription factors, using a two-stage model of rat hepatocarcinogenesis (HCC) in Wistar rats. Initiation was performed by a single intraperitoneal injection of N-nitrosodiethylamine (NDEA) (200 mg/kg) followed by promotion with phenobarbital (PB) (0.05 %) in drinking water. DMU-212 was administered by gavage in a dose of 20 or 50 mg/kg b.w. two times a week for 16 weeks. There was a significant increase in the activation of all investigated hepatic transcription factors in the NDEA/PB-induced rats. The activation of NF-κB induced by NDEA/PB treatment was suppressed by DMU-212 as evidenced by a reduction of p65 and p50 subunits translocation, DNA binding capacity, increased retention of IκB, and the reduced IKK activity. Moreover, DMU-212 reduced the level of iNOS protein induced by NDEA/PB. Treatment with DMU-212 alone increased the constitutive AP-1 subunits c-Jun and c-Fos levels and c-Jun binding to TRE consensus site. The combined treatment diminished c-Fos level and DNA binding. At a dose of 50 mg/kg, DMU-212 decreased also the STAT3 activation induced by NDEA/PB. These data indicate that DMU-212 may suppress pro-inflammatory transcription factors, particularly NF-κB, and in consequence iNOS expression in rat model of HCC which makes DMU-212 a good candidate for the development of HCC chemopreventive agent.

Resveratrol, from experimental data to nutritional evidence: the emergence of a new food ingredient

The polyphenol resveratrol is found notably in grapes and in a variety of medicinal plants. Recently, resveratrol has been suggested to have cardioprotective effects and to improve metabolic health by mimicking the effects of calorie restriction. Numerous animal and in vitro studies suggest that resveratrol could improve cardiovascular and metabolic health in humans. In view of this compelling preclinical evidence, several human studies investigating the effects of resveratrol on vascular and metabolic health have been initiated. Collectively, the animal, human epidemiological, and first human intervention studies support a role of resveratrol in vascular and metabolic health. This has led to the introduction of the first supplement and food products containing resveratrol and its emergence as a promising new health ingredient. Thus, supplementation with resveratrol may be included in nutritional and lifestyle programs aiming to reduce the risk of vascular and obesity-related problems.

Resveratrol derivatives: a patent review (2009 - 2012)

INTRODUCTION

There is currently a wealth of information on the effects of resveratrol and its derivatives in therapeutic, cosmetic and nutraceutical patent applications. Structure-activity studies of the resveratrol scaffold provide a foundation for the development of new analogs with potent activity or other beneficial properties. Ongoing research has yielded promising results and potential use in the treatment of various diseases.

AREAS COVERED

This review provides analysis of patents published from January 2009 to April 2013. There is a focus on different approaches for the production of resveratrol derivatives, combinations of new derivatives with old drugs, and applications in therapeutic areas, nutraceutical compositions and cosmetics.

EXPERT OPINION

The ability of resveratrol to interact with a disparate array of subcellular targets is uncanny. Nonetheless, even though limited or no toxicity is apparent, the molecule is not a panacea due to lack of potency and issues with bioavailability. Thus, as witnessed by a number of patents, a large assortment of derivatives have been synthesized under the guise of having superior characteristics for treating or preventing various diseases or for use as neutraceutics and cosmetics. Some of these suppositions are probably correct, but evidence-based applications are essentially nil due to a lack of commitment in terms of investing the resources necessary for the conduct of obligatory clinical trials. Current usage is largely based on anecdotes and publicity. Hopefully, at some point in time, it will be possible to follow a standard protocol with a predicable outcome.

Resveratrol enhances TNF-α production in human monocytes upon bacterial stimulation

BACKGROUND

Resveratrol is a key component of red wine that has been reported to have anti-carcinogenic and anti-aging properties. Additional studies conducted in vitro and in animal models suggested anti-inflammatory properties. However, data from primary human immune cells and in vivo studies are limited.

METHODS

A pilot study was performed including 10 healthy volunteers. Plasma cytokine levels were measured over 48h after oral application of 5g resveratrol. To verify the in vivo findings, cytokine release and gene expression in human peripheral blood mononuclear cells (PBMC) and/or monocytes was assessed after treatment with resveratrol or its metabolites and stimulation with several toll-like receptor (TLR)-agonists. Additionally, the impact on intracellular signaling pathways was analyzed using a reporter cell line and Western blotting.

RESULTS

Resveratrol treated individuals showed a significant increase in tumor necrosis factor-α (TNF-α) levels 24h after treatment compared to baseline. Studies using human PBMC or isolated monocytes confirmed potentiation of TNF-α production with different TLR agonists, while interleukin (IL)-10 was inhibited. Moreover, we observed significantly enhanced nuclear factor 'kappa-light-chain-enhancer' of activated B-cells (NF-κB) activation using a reporter cell line and found increased phosphorylation of p105, which is indicative of alternative NF-κB pathway activation.

GENERAL SIGNIFICANCE

By administering resveratrol to healthy humans and utilizing primary immune cells we were able to detect TNF-α enhancing properties of the agent. In parallel, we found enhanced alternative NF-κB activation. We report on a novel pro-inflammatory property of resveratrol which has to be considered in concepts of its biologic activity.

Antitumor effects of energy restriction-mimetic agents: thiazolidinediones

Distinct metabolic strategies used by cancer cells to gain growth advantages, such as shifting from oxidative phosphorylation to glycolysis, constitute a basis for their selective targeting as a novel approach for cancer therapy. Thiazolidinediones (TZDs) are ligands for the nuclear transcription factor peroxisome proliferator-activated receptor gamma (PPARγ) and they are clinically used as oral hypoglycemic agents. Accumulating evidence suggests that the ability of TZDs to suppress cancer cell proliferation through the interplay between apoptosis and autophagy was, at least in part, mediated through PPARγ-independent mechanisms. This review highlights recent advances in the pharmacological exploitation of the PPARγ-independent anticancer effects of TZDs to develop novel agents targeting tumor metabolism, including glucose transporter inhibitors and adenosine monophosphate-activated protein kinase, which have translational potential as cancer therapeutic agents.

Inhibitory effects of epigenetic modulators and differentiation inducers on human medulloblastoma cell lines

Background

Medulloblastoma (MB) is the most common malignant brain tumor in childhood with a 5-year survival of approximately 60%. We have recently shown that treatment of human MB cells with 5-aza-2’-deoxycytidine (5-aza-dC) reduces the clonogenic survival significantly. Here, we tested combinatorial effects of 5-aza-dC with other epigenetic (valproic acid, SAHA) and differentiation-inducing drugs (resveratrol, abacavir, retinoic acid) on human MB cells in vitro to intensify the antitumor therapy further.

Methods

Three human MB cell lines were treated with 5-aza-dC alone or in combination for three or six days. Metabolic activity was measured by WST-1 assay. To determine long-term reproductive survival, clonogenic assays were performed. Induction of DNA double-strand break (DSB) repair was measured by γH2AX assay.

Results

The applied single drugs, except for ATRA, reduced the metabolic activity dose-dependently in all MB cell lines. Longer treatment times enhanced the reduction of metabolic activity by 5-aza-dC. Combinatorial treatments showed differential, cell line-dependent responses indicating an important impact of the genetic background. 5-Aza-dC together with resveratrol was found to exert the most significant inhibitory effects on metabolic activity in all cell lines. 5-aza-dC alone reduced the clonogenicity of MB cells significantly and induced DSB with no further changes after adjuvant administration of resveratrol.

Conclusion

The observed significant decrease in metabolic activity by combinatorial treatment of MB cells with 5-aza-dC and resveratrol does not translate into long-term reproductive survival deficiency in vitro. Further studies in animal models are needed to clarify the resveratrol-mediated anticancer mechanisms in vivo.

Cytotoxicity and modulation of cancer-related signaling by (Z)- and (E)-3,4,3',5'-tetramethoxystilbene isolated from Eugenia rigida

Bioassay-guided fractionation of the leaves of Eugenia rigida yielded three stilbenes, (Z)-3,4,3',5'-tetramethoxystilbene (1), (E)-3,4,3',5'-tetramethoxystilbene (2), and (E)-3,5,4'-trimethoxystilbene (3). Their structures were determined using 1D- and 2D-NMR spectroscopy and HRESIMS. The sterically hindered Z-stereoisomer 1, a new natural product, was prepared by time-dependent photoisomerization of the E-isomer (2) under UV irradiation at λ254 nm, while 2,3,5,7-tetramethoxyphenanthrene (5) was identified at λ365 nm by UHPLC/APCI-MS and NMR spectroscopy. Compounds 1-3 were tested against a panel of luciferase reporter gene assays that assess the activity of many cancer-related signaling pathways, and the Z-isomer (1) was found to be more potent than the E-isomer (2) in inhibiting the activation of Stat3, Smad3/4, myc, Ets, Notch, and Wnt signaling, with IC50 values between 40 and 80 μM. However, both compounds showed similar inhibition against Ap-1 and NF-κB signaling. In addition, 1 demonstrated cytotoxic activity toward human leukemia cells, solid tumor cells of epidermal, breast, and cervical carcinomas, and skin melanoma, with IC50 values between 3.6 and 4.3 μM, while 2 was weakly active against leukemia, cervical carcinoma, and skin melanoma cells. Interestingly, 2 showed antioxidant activity by inhibition of ROS generation to 50% at 33.3 μM in PMA-induced HL-60 cells, while 1 was inactive at 100 μM (vs Trolox 1.4 μM).

Resveratrol vs. calorie restriction: data from rodents to humans

Calorie restriction extends lifespan and confers metabolic benefits similar to the effect of lifestyle interventions. Poor compliance to long-term dietary restriction, however, hinders the success of this approach. Evidence is now persuasive for a role of resveratrol supplementation (a polyphenol in red grapes) as potential alternative to calorie restriction. This review summarizes the latest literature on the effects and the molecular mechanisms by which calorie restriction and resveratrol confer health benefits. Resveratrol activates SIRT1 and the associated improvement in energy utilization and insulin sensitivity closely resembles the benefits of calorie restriction. Current data largely support resveratrol as a potential calorie restriction mimetic to improve metabolic and probably functional health. Future studies which characterize the bioavailability and efficacy of resveratrol supplementation are critical to provide evidence for its long-term health benefits.

Protective Effects of Resveratrol on TNF-α-Induced Endothelial Cytotoxicity in Baboon Femoral Arterial Endothelial Cells

Endothelial injury induced by inflammatory factors plays a critical role in the pathogenesis of cardiovascular disease. Endothelial cell (EC) apoptosis, proliferation, migration, and cellular adhesion molecule (CAM) expression contribute to the development of atherosclerosis. We investigated the effects of resveratrol (0.1-100  μ M) on the proliferation, migration, and CAM expression of primary cultures of baboon arterial endothelial cells (BAECs). In addition, we tested its effects under normal conditions as well as under inflammatory conditions induced by tumour necrosis factor-α (TNF-α) administered either by cotreatment, pretreatment, or posttreatment. Immunocytochemistry, MTT, wound-healing, and flow cytometry assays were performed. The resveratrol treatment significantly enhanced BAEC proliferation and attenuated TNF-α-induced impairment of proliferation at the optimal doses of 1-50 µM. Resveratrol at a high dose (100  μ M) and TNF-α impaired BAEC migration, while low doses of resveratrol (1-50  μ M) attenuated TNF-α-induced impairment of BAEC migration. Moreover, resveratrol inhibited TNF-α-induced ICAM-1 and VCAM-1 expression. Taken together, our results suggest that the resveratrol protects BAECs after inflammatory stimulation as well as ameliorates inflammatory effects at low concentrations. Consequently, resveratrol should be considered as a candidate drug for the prevention and treatment of inflammatory vascular diseases.

Resveratrol decreases periodontal breakdown and modulates local levels of cytokines during periodontitis in rats

BACKGROUND

Resveratrol (3,4',5-trihydroxystilbene) is a naturally occurring product found in numerous plants. Among its biologic properties, resveratrol may promote immunomodulatory effects on the host response. This study investigates the effect of continuous administration of resveratrol on the progression of experimental periodontitis in rats.

METHODS

Periodontitis was induced in rats in one of the first molars chosen to receive a ligature. Animals were assigned to one of two groups: 1) daily administration of the placebo solution (control group) or 2) 10 mg/kg resveratrol (RESV group). The therapies were administered systemically for 30 days: for 19 days before periodontitis induction and then for another 11 days. Then, the specimens were processed for morphometric analysis of bone loss, and the gingival tissue surrounding the first molar was collected for quantification of interleukin (IL)-1β, IL-4, and IL-17 using a multiplexing assay.

RESULTS

Intergroup comparisons of the morphometric outcomes revealed higher bone loss values in ligated molars and unligated teeth in the control group than the RESV group (P <0.05). The immunoenzymatic assay of the gingival tissue showed a lower concentration of IL-17 in the RESV group than the control group (P <0.05), whereas no differences in the IL-1β and IL-4 levels of the groups were observed (P >0.05).

CONCLUSIONS

Continuous administration of resveratrol may decrease periodontal breakdown induced experimentally in rats. In addition, lower levels of IL-17 were found in the RESV group. Future studies are important to confirm the mechanism through which resveratrol exerts its effects.

Resveratrol inhibits human nasopharyngeal carcinoma cell growth via blocking pAkt/p70S6K signaling pathways

Resveratrol (trans-3,4',5-trihydroxystilbene) has been shown to exert potent anticancer effects on various types of cancer through its anti-proliferative, anti-angiogenic, antioxidant and pro-apoptotic functions. There is still a lack of experimental evidence regarding whether resveratrol has potential anticancer activity in human nasopharyngeal carcinoma (NPC) cells. The purpose of this study was to explore the anticancer activity of resveratrol in human NPC cells both in vitro and in vivo. Our results indicated that treatment with resveratrol led to a time- and dose-dependent decrease in cell proliferation in NPC cells. A dose-dependent increase in apoptosis in response to resveratrol treatment was also observed in NPC cells. Flow cytometric analysis showed that treatment of NPC cells with resveratrol led to cell cycle arrest at the S and G2/M phases. Mechanistically, resveratrol treatment downregulated the expression of Bcl-2 and hypoxia-inducible factor-1α (HIF-1α) proteins and upregulated the expression of caspase-3 protein. In addition, resveratrol treatment also significantly decreased the phosphorylation levels of Akt1, p70S6K and p-4E-BP-1 and the protein expression of several cyclins involved in cell cycle regulation. In vivo studies further showed that resveratrol was able to significantly inhibit the growth of NPC tumor xenografts in nude mice. Collectively, our findings suggest that resveratrol exerts potent anti-prolife-rative and pro-apoptotic effects on human NPC cells possibly through interfering with the pAkt1/p70S6K signaling pathways, thus it may potentially be developed as an effective agent for chemoprevention and chemotherapy of human NPC.

Dietary grape polyphenol resveratrol increases mammary tumor growth and metastasis in immunocompromised mice

Background

Resveratrol, a polyphenol from grapes and red wine has many health beneficial effects, including protection against cardiovascular and neurodegenerative diseases and cancer. However, our group and others have provided evidence for a dual cancer promoting or inhibitory role for resveratrol in breast cancer, dependent on estrogenic or antiestrogenic activities. Moreover, much of the inhibitory effects of resveratrol have been reported from studies with high non-physiological concentrations.

Methods

We investigated the effects of a range of concentrations (0.5, 5, 50 mg/kg body weight) of resveratrol on mammary tumor development post-initiation, using immunocompromised mice.

Results

Our findings suggest promotion of mammary tumor growth and metastasis by resveratrol at all concentrations tested in tumors derived from the low metastatic estrogen receptor (ER)α(-), ERβ(+) MDA-MB-231 and the highly metastatic ER(-) MDA-MB-435 cancer cell lines. Additionally, the activity of the migration/invasion regulator Rac, which we have previously shown to be regulated by resveratrol in vitro, was measured in tumors from resveratrol treated mice. Our results show a significant induction of tumoral Rac activity and a trend in increased expression of the Rac downstream effector PAK1 and other tumor promoting molecules following resveratrol treatment.

Conclusion

Taken together, our findings implicate low concentrations of resveratrol in potential promotion of breast cancer. Therefore, this study illuminates the importance of further delineating resveratrol’s concentration dependent effects, particularly in breast cancer, before it can be tested in the clinic or used as a dietary supplement for breast cancer patients.