Control of prostate cell growth, DNA damage and repair and gene expression by resveratrol analogues, in vitro

Research progress of SIRTs activator resveratrol and its derivatives in autoimmune diseases

Autoimmune diseases (AID) have emerged as prominent contributors to disability and mortality worldwide, characterized by intricate pathogenic mechanisms involving genetic, environmental, and autoimmune factors. In response to this challenge, a growing body of research in recent years has delved into genetic modifications, yielding valuable insights into AID prevention and treatment. Sirtuins (SIRTs) constitute a class of NAD-dependent histone deacetylases that orchestrate deacetylation processes, wielding significant regulatory influence over cellular metabolism, oxidative stress, immune response, apoptosis, and aging through epigenetic modifications. Resveratrol, the pioneering activator of the SIRTs family, and its derivatives have captured global scholarly interest. In the context of AID, these compounds hold promise for therapeutic intervention by modulating the SIRTs pathway, impacting immune cell functionality, suppressing the release of inflammatory mediators, and mitigating tissue damage. This review endeavors to explore the potential of resveratrol and its derivatives in AID treatment, elucidating their mechanisms of action and providing a comprehensive analysis of current research advancements and obstacles. Through a thorough examination of existing literature, our objective is to advocate for the utilization of resveratrol and its derivatives in AID treatment while offering crucial insights for the formulation of innovative therapeutic approaches.

Nutritional epigenomic and DNA-damage modulation effect of natural stilbenoids

The aim of the present work is the evaluation of biological effects of natural stilbenoids found in Vitis vinifera, with a focus on their activity as epigenetic modulators. In the present study, resveratrol, pterostilbene and for the first time their dimers (±)-trans-δ-viniferin, (±)-trans-pterostilbene dehydrodimer were evaluated in Caco-2 and HepG-2 cell lines as potential epigenetic modulators. Stilbenoids were added in a Caco-2 cell culture as a model of the intestinal epithelial barrier and in the HepG-2 as a model of hepatic environment, to verify their dose-dependent toxicity, ability to interact with DNA, and epigenomic action. Resveratrol, pterostilbene, and (±)-trans-pterostilbene dehydrodimer were found to have no toxic effects at tested concentration and were effective in reversing arsenic damage in Caco-2 cell lines. (±)-trans-δ-viniferin showed epigenomic activity, but further studies are needed to clarify its mode of action.

Plant-Derived Stilbenoids as DNA-Binding Agents: From Monomers to Dimers

Stilbenoids are natural compounds endowed with several biological activities, including cardioprotection and cancer prevention. Among them, (±)-trans-δ-viniferin, deriving from trans-resveratrol dimerization, was investigated in its ability to target DNA duplex and G-quadruplex structures by exploiting NMR spectroscopy, circular dichroism, fluorescence spectroscopy and molecular docking. (±)-trans-δ-Viniferin proved to bind both the minor and major grooves of duplexes, whereas it bound the 3'- and 5'-ends of a G-quadruplex by stacking on the outer quartets, accompanied by rearrangement of flanking residues. Specifically, (±)-trans-δ-viniferin demonstrated higher affinity for the investigated DNA targets than its monomeric counterpart. Additionally, the methoxylated derivatives of (±)-trans-δ-viniferin and trans-resveratrol, i. e. (±)-pterostilbene-trans-dihydrodimer and trans-pterostilbene, respectively, were evaluated, revealing similar binding modes, affinities and stoichiometries with the DNA targets as their parent analogues. All tested compounds were cytotoxic at μM concentration on several cancer cell lines, showing DNA damaging activity consistent with their ability to tightly interact with duplex and G-quadruplex structures.

Natural Compounds That Target DNA Repair Pathways and Their Therapeutic Potential to Counteract Cancer Cells

Resistance to current cancer treatments is an important problem that arises through various mechanisms, but one that stands out involves an overexpression of several factors associated with DNA repair. To counteract this type of resistance, different drugs have been developed to affect one or more DNA repair pathways, therefore, to test different compounds of natural origin that have been shown to induce cell death in cancer cells is paramount. Since natural compounds target components of the DNA repair pathways, they have been shown to promote cancer cells to be resensitized to current treatments. For this and other reasons, natural compounds have aroused great curiosity and several research projects are being developed around the world to establish combined treatments between them and radio or chemotherapy. In this work, we summarize the effects of different natural compounds on the DNA repair mechanisms of cancer cells and emphasize their possible application to re-sensitize these cells.

Human Skin Lightening Efficacy of Resveratrol and Its Analogs: From in Vitro Studies to Cosmetic Applications

Antioxidants are deemed useful in controlling oxidative stress associated with extrinsic skin aging and pigmentation disorders. Resveratrol is a polyphenol compound found in many edible plants such as Vitis vinifera, and its inhibitory effects on the catalytic activity, gene expression, and posttranslational modifications of tyrosinase, a key enzyme in the melanin biosynthetic pathway, provide a mechanistic basis for its antimelanogenic effects seen in melanocytic cells, three-dimensionally reconstituted skin models, and in vivo animal models. As a potent antioxidant and a modulator of nuclear factor erythroid 2-related factor 2 (Nrf2), and sirtuin 1, resveratrol can also regulate multiple signaling pathways associated with inflammation and premature aging. Recent clinical studies have supported the efficacy of resveratrol and its analogs, such as resveratryl triacetate (RTA) and resveratryl triglycolate (RTG), in human skin lightening and antiaging. These findings suggest that resveratrol and its analogs are potentially useful as skin lightening and antiaging agents in cosmetics.

Alcohol Intake and Risk of Lethal Prostate Cancer in the Health Professionals Follow-Up Study

PURPOSE

It is unknown whether alcohol intake is associated with the risk of lethal (metastatic or fatal) prostate cancer. We examine (1) whether alcohol intake among men at risk of prostate cancer is associated with diagnosis of lethal prostate cancer and (2) whether intake among men with nonmetastatic prostate cancer is associated with metastasis or death.

METHODS

This prospective cohort study uses the Health Professionals Follow-Up Study (1986 to 2012). Our analysis of alcohol intake among men at risk of prostate cancer included 47,568 cancer-free men. Our analysis of alcohol intake among men with prostate cancer was restricted to 5,182 men diagnosed with nonmetastatic prostate cancer during follow-up. We examine the association of total alcohol, red and white wine, beer, and liquor with lethal prostate cancer and death. Multivariate Cox proportional hazards regression estimated hazard ratios (HRs) and 95% CIs.

RESULTS

Alcohol drinkers had a lower risk of lethal prostate cancer (any v none: HR, 0.84 [95% CI, 0.71 to 0.99]) without a dose-response relationship. Total alcohol intake among patients with prostate cancer was not associated with progression to lethal prostate cancer (any v none: HR, 0.99 [95% CI, 0.57 to 1.72]), whereas moderate red wine intake was associated with a lower risk (any v none: HR, 0.50 [95% CI, 0.29 to 0.86]; P trend = .05). Compared with none, 15 to 30 g/d of total alcohol after prostate cancer diagnosis was associated with a lower risk of death (HR, 0.71 [95% CI, 0.50 to 1.00]), as was red wine (any v none: HR, 0.74 [95% CI, 0.57 to 0.97]; P trend = .007).

CONCLUSION

Cancer-free men who consumed alcohol had a slightly lower risk of lethal prostate cancer compared with abstainers. Among men with prostate cancer, red wine was associated with a lower risk of progression to lethal disease. These observed associations merit additional study but provide assurance that moderate alcohol consumption is safe for patients with prostate cancer.

Triacetyl resveratrol upregulates miRNA‑200 and suppresses the Shh pathway in pancreatic cancer: A potential therapeutic agent

Trans‑3,4',5‑trihydroxystilbene (resveratrol) is a naturally occurring polyphenolic phytoalexin with marked anticancer activities, and is mainly found in grapes, berries and peanuts. However, due to a low bioavailability, it has not progressed to clinical practice for cancer treatment. Therefore, the aims of the present study were to examine the anticancer activities of the resveratrol derivative, triacetyl resveratrol (TCRV), in pancreatic cancer cells. Apoptosis was measured by fluorescence‑activated cell sorting and terminal deoxynucleotidyl transferase (TdT)‑mediated dUTP nick‑end labeling assays. Gene expression was measured by reverse transcription‑quantitative polymerase chain reaction. TCRV inhibited colony formation and induced apoptosis through caspase‑3 activation in human pancreatic cancer AsPC‑1 and PANC‑1 cells, whereas it exerted no effect on human pancreatic normal ductal epithelial cells (HPNE). TCRV inhibited epithelial‑mesenchymal transition (EMT) by upregulating the expression of E‑cadherin and suppressing the expression of N‑cadherin and the transcription factors, Snail, Slug and Zeb1. TCRV inhibited Zeb1 3'UTR‑luciferase activity through the upregulation of microRNA (miR)‑200 family members. The inhibitory effects of TCRV on pancreatic cancer cell migration and invasion were counteracted by anti‑miR‑200 family members. The inhibitory effects of TCRV on EMT and the induction of apoptosis were exerted through the suppression of the sonic hedgehog (Shh) pathway, and through the modulation of cyclin D1 and Bcl‑2 expression. The hyperactivation of the Shh pathway by either Shh protein or Gli1 overexpression abrogated the biological effects of TCRV. Taken together, the results of this study demonstrate that TCRV inhibits pancreatic cancer growth and EMT by targeting the Shh pathway and its downstream signaling mediators. TCRV inhibited EMT through the upregulation of miR‑200 family members. Since TCRV effectively inhibited the growth of human pancreatic cancer cells by modulating the Shh pathway, without affecting the growth of HPNE cells, our findings suggest the possible use of TCRV as a promising candidate for the treatment and/or prevention of pancreatic cancer.

Synthetic resveratrol-curcumin hybrid derivative inhibits mitosis progression in estrogen positive MCF-7 breast cancer cells

Curcumin (1) and resveratrol (2) are bioactive natural compounds that display wide pharmacological properties, including antitumor activity. However, their clinical application has been limited due to their low solubility and bioavailability. Nevertheless, independent studies have considered these compounds as interesting prototypes for developing new chemical structures useful for anticancer therapy. Here in, we report the synthesis of novel curcumin-like hydrazide analogues (3a and 3b), and a series of curcumin-resveratrol hybrid compounds (4a-f), and the evaluation of their cytotoxic potential on three tumor cell lines MCF-7 (breast), A549 (lung), and HepG2 (liver). Cell viability was significantly reduced in all tested cell lines when compounds 4c-4e were used. The IC50 values for these compounds on MCF-7 cells were lower than those for curcumin, resveratrol, or curcumin combined with resveratrol. We evidenced that 4c promoted a drastic increase of G2/M population. The accumulation of cells in mitosis onset in treated cultures was due to, at least in part, the ability of 4c to modulate nuclear kinase proteins, which orchestrate important events in mitosis progression. We have also observed significant reduction of the relative RNAm abundance of CCNB1, PLK1, AURKA, AURKB in samples treated with 4c, with concomitant increase of CDKN1A (p21). Thus, compound 4c is a promising multi-target antitumor agent that should be considered for further in vivo studies.

Functional/activity network (FAN) analysis of gene-phenotype connectivity liaised by grape polyphenol resveratrol

Resveratrol is a polyphenol that has witnessed an unprecedented yearly growth in PubMed citations since the late 1990s. Based on the diversity of cellular processes and diseases resveratrol reportedly affects and benefits, it is likely that the interest in resveratrol will continue, although uncertainty regarding its mechanism in different biological systems remains.

We hypothesize that insights on disease-modulatory activities of resveratrol might be gleaned by systematically dissecting the publicly available published data on chemicals and drugs. In this study, we tested our hypothesis by querying DTome (Drug-Target Interactome), a web-based tool containing data compiled from open-source databases including DrugBank, PharmGSK, and Protein Interaction Network Analysis (PINA). Four direct protein targets (DPT) and 219 DPT-associated genes were identified for resveratrol. The DPT-associated genes were scrutinized by WebGestalt (WEB-based Gene SeT Analysis Toolkit). This enrichment analysis resulted in 10 identified KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways. Refined analysis of KEGG pathways showed that 2 — one linked to p53 and a second to prostate cancer — have functional connectivity to resveratrol and its four direct protein targets. These results suggest that a functional activity network (FAN) approach may be considered as a new paradigm for guiding future studies of resveratrol. FAN analysis resembles a BioGPS, with capability for mapping a Web-based scientific track that can productively and cost effectively connect resveratrol to its primary and secondary target proteins and to its biological functions.

Resveratrol, piceatannol and analogs inhibit activation of both wild-type and T877A mutant androgen receptor

Prostate cancer growth and progression are mainly dependent on androgens and many current prostate cancer treatment options target the synthesis or function of androgens. We have previously reported that resveratrol and synthetic analogs of resveratrol with a higher bioavailability inhibit the synthesis of androgens in human adrenocortical H295R cells. Now we have studied the antiandrogenic properties of resveratrol, piceatannol and analogs in two different prostate cell lines; LNCaP and RWPE. LNCaP carry a T877A mutation in the androgen receptor while RWPE has a wild-type androgen receptor. We found that resveratrol, piceatannol and all studied analogs were able to inhibit a dihydrotestosterone-induced activation of the androgen receptor, showing that they act as antiandrogens. In LNCaP cells, all studied compounds were able to statistically significantly decrease the androgenic signaling in concentrations ≥1μM and the synthetic analogs trimethylresveratrol (RSVTM) and tetramethylpiceatannol (PICTM) were the most potent compounds. RWPE cells were not as responsive to the studied compounds as the LNCaP cells. A statistically significant decrease in the androgenic signaling was observed at concentrations ≤5μM for most compounds and RSVTM was found to be the most potent compound. Further, we studied the effects of resveratrol, piceatannol and analogs on the levels of prostate-specific antigen (PSA) in LNCaP cells and found that all studied compounds decreased the level of PSA and that the synthetic analogs diacetylresveratrol (RSVDA), triacetylresveratrol (RSVTA) and RSVTM were the most potent compounds, decreasing the PSA level by approx. 50% at concentrations ≥10μM. In a cell-free receptor binding assay we were unable to show binding of resveratrol or analogs to the ligand binding domain of the androgen receptor, indicating that the observed effects are mediated via other mechanisms than direct ligand competition. We conclude that the resveratrol, piceatannol and analogs are highly interesting for chemoprevention of prostate cancer, since they have a high potency both as inhibitors of androgen synthesis and androgen receptor activation.

Cytotoxicity and genotoxicity of stilbene derivatives in CHO-K1 and HepG2 cell lines

The cytotoxicity and genotoxicity of the stilbenes (E)-methyl-4-(3-5-dimethoxystyryl)benzoate (ester), (E)-4-(3-5-dimethoxystyryl)aniline (amino), (Z)-1,3-dimethoxy-5-(4-methoxystyryl)benzene (cis-TMS) and (E)-1,3-dimethoxy-5-(4-methoxystyryl)benzene (trans-TMS) were investigated in this work. Structural modifications of resveratrol, a naturally occurring stilbene, have been previously performed, including the replacement of hydroxyl by different functional groups. Such modifications resulted in significant improvement of target-specific effects on cell death and antiproliferative responses. The parameters were evaluated using XTT assay, clonogenic survival assay and the cytokinesis-block micronucleus assay in CHO-K1 and HepG2 cell lines. The results showed that cis-TMS is approximately 250-fold more cytotoxic than the amino and ester, and 128-fold more cytotoxic than trans-TMS. When genotoxicity was evaluated, only the trans-TMS did not significantly increase the frequency of micronucleus (MN). While the cis-TMS induced a mean of 5.2 and 5.9 MN/100 cells at 0.5 μM in CHO-K1 and HepG2, respectively, the amino and ester induced 3.1 and 3.6 MN/100 cells at 10 μM in CHO-K1, respectively, and 3.5 and 3.8 in HepG2. Trans-TMS is genotoxic only in HepG2 cells. Based on these results, the cis-TMS was the most cytotoxic and genotoxic compound in both cell lines.

Cancer Chemoprevention by Resveratrol: The p53 Tumor Suppressor Protein as a Promising Molecular Target

Increasing epidemiological and experimental evidence has demonstrated an inverse relationship between the consumption of plant foods and the incidence of chronic diseases, including cancer. Microcomponents that are naturally present in such foods, especially polyphenols, are responsible for the benefits to human health. Resveratrol is a diet-derived cancer chemopreventive agent with high therapeutic potential, as demonstrated by different authors. The aim of this review is to collect and present recent evidence from the literature regarding resveratrol and its effects on cancer prevention, molecular signaling (especially regarding the involvement of p53 protein), and therapeutic perspectives with an emphasis on clinical trial results to date.

Resveratrol derivatives: an updated patent review (2012-2015)

INTRODUCTION

Resveratrol is a well-studied natural small molecule that possesses diverse bioactivities. Chemical derivation based on the resveratrol scaffold is of great importance to overcome the drawbacks of resveratrol and to improve its therapeutic potential. Continuous efforts have been established to develop resveratrol derivatives that target different therapeutic applications. Areas covered: This review covers patents published from 2012 to 2015. All resveratrol derivatives discussed are classified based on its derivation strategy as simple derivatives, conjugated derivatives and miscellaneous derivatives. Their therapeutic related activities are reviewed and discussed. Expert opinion: Chemical derivation is an effective strategy to enhance the benefits of resveratrol and ameliorate its disadvantages. Recent studies on resveratrol derivatives have made great progress in the treatment of cancer and neurodegenerative diseases to name a few, demonstrating improved activity compared with resveratrol. Notably, its bioavailability was also improved in some cases. However, the 'next generation' of resveratrol derivatives still requires the development of new strategies and techniques.

Resveratrol affects protein kinase C activity and promotes apoptosis in human colon carcinoma cells

BACKGROUND

Resveratrol has been reported to have potential chemopreventive and apoptosis-inducing properties in a variety of tumor cell lines.

OBJECTIVE

In this study, to investigate the effects of resveratrol on protein kinase C (PKC) activity and apoptosis in human colon carcinoma cells, we used HT-29 cells and examined the PKCα and ERK1/2 signaling pathways.

METHODS

To test the effects of resveratrol on the growth of HT- 29 cells, the cells were exposed to varying concentrations and assessed with the the MTT cell-viability assay. Fluorescence-activated cell sorter (FACS) analysis was applied to determine the effects of resveratrol on cell apoptosis. Western blotting was performed to determine the protein levels of PKCα and ERK1/2. In inhibition experiments, HT-29 cells were treated with Go?6976 or PD98059 for 30 min, followed by exposure to 200 μM resveratrol for 72 h.

RESULTS

Resveratrol had a significant inhibitory effect on HT-29 cell growth. FACS revealed that resveratrol induced apoptosis. Western blotting showed that e phosphorylation of PKCα and ERK1/2 was significantly increased in response to resveratrol treatment. Pre-treatment with PKCα and ERK1/2 inhibitors (Go?6976 and PD98059) promoted apoptosis.

CONCLUSION

Resveratrol has significant anti-proliferative effects on the colon cancer cell line HT-29. The PKC- ERK1/2 signaling pathway can partially mediate resveratrol-induced apoptosis of HT-29 cells.

Epigenetic potential of resveratrol and analogs in preclinical models of prostate cancer

Lifestyle, particularly diet, is a risk factor for prostate cancer. Dietary polyphenols such as resveratrol possess anticancer properties and therefore have chemopreventive and therapeutic potential. Resveratrol has pleiotropic effects, exerting its biological activity through multiple pathways and targets, including those associated with cancer. Numerous studies have demonstrated the anticancer effects of resveratrol and, to a lesser extent, its analogs, in tissue culture, while in vivo observations are limited. Here, we provide a concise summary of our results on epigenetic mechanisms of resveratrol and analogs mediated through regulation of chromatin modifier metastasis-associated protein 1 (MTA1) and microRNAs (miRNAs), and highlight the anticancer effects of these compounds in preclinical models of prostate cancer. We suggest that the identified stilbene responsive mechanism-based biomarkers, such as MTA1 and oncogenic miRNAs, may become indicative of treatment efficacy in prostate cancer. Resveratrol analogs with better bioavailability, conferring superior pharmacological potencies and greater anticancer effects, may become stronger candidates for clinical development.

A study of the human skin-whitening effects of resveratryl triacetate

Resveratrol has a variety of bioactivities that include its anti-melanogenic effects, but its use in cosmetics has been challenging partly because of its chemical instability. Resveratryl triacetate (RTA) is a prodrug that can enhance stability. The purpose of this study was to examine the skin safety and whitening effects of RTA in human subjects. The primary skin irritation potentials of RTA and resveratrol were tested at 0.1 and 0.5 % on human subjects. Resveratrol at a concentration of 0.5 % induced weak skin irritation, whereas RTA did not induce any skin responses. The skin-whitening efficacy of a cosmetic formulation containing 0.4 % RTA was evaluated in two different test models. In the artificial tanning model, the test product and the control product were applied twice daily to the skin of the forearms of 22 human subjects after pigmentation induction by ultraviolet irradiation. Applying the test and the control products to the artificial tanning model for 8 weeks increased the individual topology angles (ITA°) by 17.06 and 13.81 %, respectively, a difference that was statistically significant (p < 0.05). In the hyperpigmentation model, the test product and the control product were applied twice daily to the faces of 21 human subjects. The averaged intensity of the hyperpigmented spots decreased by 2.67 % in the test group and 1.46 % in the control group, a difference that was statistically significant (p < 0.05). Therefore, RTA incorporated into cosmetic formulations can whiten human skin without inducing skin irritation.

3,4',5-trans-Trimethoxystilbene; a natural analogue of resveratrol with enhanced anticancer potency

Resveratrol is a phytoalexin produced by many plant species as a defence mechanism. Over the last decade, this polyphenol has been reported to be active against multiple targets associated with chronic disorders. However, its poor pharmacokinetic profile, as well as multiple discrepancies related to its in vitro and in vivo profile, has resulted not only on the study of suitable delivery systems, but the use of resveratrol derivatives. In this regard, the 3,4',5-trans-trimethoxystilbene (TMS), a natural analogue of resveratrol, has emerged as a strong candidate. TMS has an enhanced anticancer profile compared to resveratrol, exhibiting higher potency than resveratrol, as shown by multiple reports describing an improved cancer cell proliferation inhibition, induction of cell cycle arrest, decreased metastasis, reduced angiogenesis, and increased apoptosis. In this review, we provide a concise summary of results reported in the literature, related to the similarities and differences between resveratrol and TMS, and we submit to the scientific community that TMS is a promising and (still) understudied natural agent candidate, with potential applications in cancer research. Nevertheless, based on the available evidence, we also submit to the scientific community that TMS may also find a niche in any other research area in which resveratrol has been used.

Effects of resveratrol, oxyresveratrol, and their acetylated derivatives on cellular melanogenesis

Resveratrol and oxyresveratrol are naturally occurring phenolic compounds with various bioactivities, but their uses in cosmetics have been partly limited by their chemical instabilities. This study was performed to examine the anti-melanogenic effects of the acetylated derivatives from resveratrol and oxyresveratrol. Resveratrol and oxyresveratrol were chemically modified to triacetyl resveratrol and tetraacetyl oxyresveratrol, respectively. The acetylated compounds were less susceptible than the parent compounds to oxidative discoloration. The acetylated compounds inhibited the activities of tyrosinases less than parent compounds in vitro, but they were as effective at cellular melanogenesis inhibition, indicating bioconversion to parent compounds inside cells. Supporting this notion, the parent compounds were regenerated when the acetylated compounds were digested with cell lysates. Although resveratrol and triacetyl resveratrol inhibited tyrosinase activity less effectively than oxyresveratrol and tetraacetyl oxyresveratrol in vitro, they inhibited cellular melanogenesis more effectively. This discrepancy was explained by strong inhibition of tyrosinase expression by resveratrol and triacetyl resveratrol. Experiments using a reconstituted skin model indicated that resveratrol derivatives can affect melanin synthesis and cell viability to different extents. Collectively, this study suggests that acetylated derivatives of resveratrol have great potential as anti-melanogenic agents for cosmetic use in terms of efficacy, safety, and stability.

Trimethoxy-resveratrol and piceatannol administered orally suppress and inhibit tumor formation and growth in prostate cancer xenografts

BACKGROUND

Resveratrol (Res) is recognized as a promising cancer chemoprevention dietary polyphenol with antioxidative, anti-inflammatory, and anticancer properties. However, the role of its analogues in prostate cancer (PCa) chemoprevention is unknown.

METHODS

We synthesized several natural and synthetic analogues of Res and characterized their effects on PCa cells in vitro using a cell proliferation assay. A colony formation assay and in vitro validation of luciferase (Luc) activity was done for LNCaP-Luc cells that were consequently used for in vivo studies. The efficacy of Res, trimethoxy-resveratrol (3M-Res) and piceatannol (PIC) was studied in a subcutaneous (s.c.) model of PCa using oral gavage. Tumor progression was monitored by traditional caliper and bioluminescent imaging. The levels of cytokines in serum were examined by ELISA, and the levels of compounds in serum and tumor tissues were determined by gas chromatography-mass spectrometry.

RESULTS

We examined the anti-proliferative activities of Res/analogues in three PCa cell lines. We further compared the chemopreventive effects of oral Res, 3M-Res, and PIC in LNCaP-Luc-xenografts. We found that 2 weeks pretreatment with the compounds diminished cell colonization, reduced tumor volume, and decreased tumor growth in the xenografts. Both 3M-Res and PIC demonstrated higher potency in inhibiting tumor progression compared to Res. Notably, 3M-Res was the most active in inhibiting cell proliferation and suppressing colony formation, and its accumulation in both serum and tumor tissues was the highest.

CONCLUSIONS

Our findings offer strong pre-clinical evidence for the utilization of dietary stilbenes, particularly 3M-Res, as novel, potent, effective chemopreventive agents in PCa.

Dendrimer nanoscaffolds for potential theranostics of prostate cancer with a focus on radiochemistry

Dendrimers are a class of structurally defined macromolecules featured with a central core, a low-density interior formed by repetitive branching units, and a high-density exterior terminated with surface functional groups. In contrast to their polymeric counterparts, dendrimers are nanosized and symmetrically shaped, which can be reproducibly synthesized on a large scale with monodispersity. These unique features have made dendrimers of increasing interest for drug delivery and other biomedical applications as nanoscaffold systems. Intended to address the potential use of dendrimers for the development of theranostic agents, which combines therapeutics and diagnostics in a single entity for personalized medicine, this review focuses on the reported methodologies of using dendrimer nanoscaffolds for targeted imaging and therapy of prostate cancer. Of particular interest, relevant chemistry strategies are discussed due to their important roles in the design and synthesis of diagnostic and therapeutic dendrimer-based nanoconjugates and potential theranostic agents, targeted or nontargeted. Given the developing status of nanoscaffolded theranostics, major challenges and potential hurdles are discussed along with the examples representing current advances.

Epigenetic mechanisms in anti-cancer actions of bioactive food components--the implications in cancer prevention

The hallmarks of carcinogenesis are aberrations in gene expression and protein function caused by both genetic and epigenetic modifications. Epigenetics refers to the changes in gene expression programming that alter the phenotype in the absence of a change in DNA sequence. Epigenetic modifications, which include amongst others DNA methylation, covalent modifications of histone tails and regulation by non-coding RNAs, play a significant role in normal development and genome stability. The changes are dynamic and serve as an adaptation mechanism to a wide variety of environmental and social factors including diet. A number of studies have provided evidence that some natural bioactive compounds found in food and herbs can modulate gene expression by targeting different elements of the epigenetic machinery. Nutrients that are components of one-carbon metabolism, such as folate, riboflavin, pyridoxine, cobalamin, choline, betaine and methionine, affect DNA methylation by regulating the levels of S-adenosyl-L-methionine, a methyl group donor, and S-adenosyl-L-homocysteine, which is an inhibitor of enzymes catalyzing the DNA methylation reaction. Other natural compounds target histone modifications and levels of non-coding RNAs such as vitamin D, which recruits histone acetylases, or resveratrol, which activates the deacetylase sirtuin and regulates oncogenic and tumour suppressor micro-RNAs. As epigenetic abnormalities have been shown to be both causative and contributing factors in different health conditions including cancer, natural compounds that are direct or indirect regulators of the epigenome constitute an excellent approach in cancer prevention and potentially in anti-cancer therapy.

High-throughput library screening identifies two novel NQO1 inducers in human lung cells

Many phytochemicals possess antioxidant and cancer-preventive properties, some putatively through antioxidant response element-mediated phase II metabolism, entailing mutagen/oxidant quenching. In our recent studies, however, most candidate phytochemical agents were not potent in inducing phase II genes in normal human lung cells. In this study, we applied a messenger RNA (mRNA)-specific gene expression-based high throughput in vitro screening approach to discover new, potent plant-derived phase II inducing chemopreventive agents. Primary normal human bronchial epithelial (NHBE) cells and immortalized human bronchial epithelial cells (HBECs) were exposed to 800 individual compounds in the MicroSource Natural Products Library. At a level achievable in humans by diet (1.0 μM), 2,3-dihydroxy-4-methoxy-4'-ethoxybenzophenone (DMEBP), triacetylresveratrol (TRES), ivermectin, sanguinarine sulfate, and daunorubicin induced reduced nicotinamide adenine dinucleotide phosphate:quinone oxidoreductase 1 (NQO1) mRNA and protein expression in NHBE cells. DMEBP and TRES were the most attractive agents as coupling potency and low toxicity for induction of NQO1 (mRNA level, ≥3- to 10.8-fold that of control; protein level, ≥ two- to fourfold that of control). Induction of glutathione S-transferase pi mRNA expression was modest, and none was apparent for glutathione S-transferase pi protein expression. Measurements of reactive oxygen species and glutathione/oxidized glutathione ratio showed an antioxidant effect for DMEBP, but no definite effect was found for TRES in NHBE cells. Exposure of NHBE cells to H(2)O(2) induced nuclear translocation of nuclear factor erythroid 2-related factor 2, but this translocation was not significantly inhibited by TRES and DMEBP. These studies show that potency and low toxicity may align for two potential NQO1-inducing agents, DMEBP and TRES.