Resveratrol enhances ultraviolet B-induced cell death through nuclear factor-kappaB pathway in human epidermoid carcinoma A431 cells

Bibliometric and visualized analysis of resveratrol in anticancer investigations

A growing number of publications have shown that resveratrol has anticancer effects and has become a hotspot in cancer research. The purpose of this study is to analyze the academic results and research trends in resveratrol within the field of anticancer and to predict the future trends in this field. We conducted a literature search for resveratrol in anticancer research from 2003 to 2022 using the Science Citation Index Expanded of the Web of Science Core Collection. The visualization software was used to perform the bibliometric analysis. A total of 1463 publications from 2003 to 2022 were retrieved. China had the highest number of publications. Taipei Medical University became the research institution with the largest number of publications worldwide. The journals with the highest output and co-citation frequency were Molecules and Cancer Research. Levenson, Anait S and Jaeger, Walter published the largest number of papers. Jang, MS was the most co-cited author. Timeline View shows trends and relationship between research topics over time and suggests that the emerging frontier of resveratrol in anticancer may be "resveratrol induces apoptosis." As more and more evidence shows the important role of resveratrol in anticancer, further research on its mechanisms and target discovery may become a major direction for future research. The bibliometric analysis findings of this study will significantly contribute to scholars' comprehensive understanding of the anticancer effects and mechanisms of action of resveratrol, aiding in delineating research hotspots and frontier directions within this field, thereby providing guidance for future investigations.

Potential of natural products in osteosarcoma treatment: Focus on molecular mechanisms

Osteosarcoma is the most frequent type of bone cancer found in children and adolescents, and commonly arises in the metaphyseal region of tubular long bones. Standard therapeutic approaches, such as surgery, chemotherapy, and radiation therapy, are used in the management of osteosarcoma. In recent years, the mortality rate of osteosarcoma has decreased due to advances in treatment methods. Today, the scientific community is investigating the use of different naturally derived active principles against various types of cancer. Natural bioactive compounds can function against cancer cells in two ways. Firstly they can act as classical cytotoxic compounds by non-specifically affecting macromolecules, such as DNA, enzymes, and microtubules, which are also expressed in normal proliferating cells, but to a greater extent by cancer cells. Secondly, they can act against oncogenic signal transduction pathways, many of which are activated in cancer cells. Some bioactive plant-derived agents are gaining increasing attention because of their anti-cancer properties. Moreover, some naturally-derived compounds can significantly promote the effectiveness of standard chemotherapy drugs, and in certain cases are able to ameliorate drug-induced adverse effects caused by chemotherapy. In the present review we summarize the effects of various naturally-occurring bioactive compounds against osteosarcoma.

Resveratrol and other dietary polyphenols are inhibitors of estrogen metabolism in human breast cancer cells

Polyphenols in foods and dietary supplements are commonly used for the prevention and treatment of a variety of malignancies, including breast cancer. However, daily intake by patients with breast cancer is controversial, as these compounds may stimulate cancer growth. Estrogens serve key roles in breast cancer cell proliferation; therefore, understanding the interaction between endogenous steroid hormones and natural dietary polyphenols is essential. Currently, comprehensive knowledge regarding these effects remains limited. The current review summarizes the dose-dependent in vitro and in vivo interactions of resveratrol and other dietary polyphenols with estrogen precursors, active estrogens, catechol estrogens and their respective glucuronidated, sulfated, glutathionated or O-methylated metabolites in estrogen receptor alpha negative (ERα-) and positive (ERα+) breast cancer. Which estrogen-metabolizing enzymes are affected by polyphenols is also reviewed in detail. Furthermore, the impacts of dose and therapy duration on disease development and progression in patients with breast cancer are discussed. The present article is part of a Special Issue titled 'CSR 2018'.

Bioactive Ingredients in Chinese Herbal Medicines That Target Non-coding RNAs: Promising New Choices for Disease Treatment

Chinese herbal medicines (CHMs) are widely used in China and have long been a powerful method to treat diseases in Chinese people. Bioactive ingredients are the main components extracted from herbs that have therapeutic properties. Since artemisinin was discovered to inhibit malaria by Nobel laureate Youyou Tu, extracts from natural plants, particularly bioactive ingredients, have aroused increasing attention among medical researchers. The bioactive ingredients of some CHMs have been found to target various non-coding RNA molecules (ncRNAs), especially miRNAs, lncRNAs, and circRNAs, which have emerged as new treatment targets in numerous diseases. Here we review the evidence that, by regulating the expression of ncRNAs, these ingredients exert protective effects, including pro-apoptosis, anti-proliferation and anti-migration, anti-inflammation, anti-atherosclerosis, anti-infection, anti-senescence, and suppression of structural remodeling. Consequently, they have potential as treatment agents in diseases such as cancer, cardiovascular disease, nervous system disease, inflammatory bowel disease, asthma, infectious diseases, and senescence-related diseases. Although research has been relatively limited and inadequate to date, the promising choices and new alternatives offered by bioactive ingredients for the treatment of the above diseases warrant serious investigation.

Rbfox2 dissociation from stress granules suppresses cancer progression

Stress granules (SGs) are stalled translation initiation complexes comprising untranslated mRNAs and RNA-binding proteins (RBPs). RBP fox-1 homolog 2 (Rbfox2), a component of SGs, binds to retinoblastoma 1 (RB1) mRNA, which is closely related to cancer progression; however, the role of Rbfox2 in cancer progression remains largely unknown. In this study, we confirmed that Rbfox2, which is present in the nucleus as a splicing regulator, localizes to the cytoplasm of human colon cancer tissues and that induction of Rbfox2 dissociation from SGs by resveratrol treatment inhibits cancer progression. We also observed that Rbfox2 in SGs inhibited RB1 protein expression and promoted cell cycle progression. Additionally, resveratrol treatment inhibited SG-mediated Rbfox2 localization, further inhibiting RB1 protein expression, and inhibited specific Rbfox2 localization to the cytoplasm in melanoma B16-F10 cells, thereby effectively inhibiting metastasis and tumor growth ability. These results indicate that Rbfox2 dissociation from SGs attenuates cancer progression and offer insight into the mechanism associated with Rbfox2 dissociation, thereby marking Rbfox2 as a potential candidate target for cancer therapy.

Resveratrol, an antioxidant found in red grapes, slows cancer progression by interfering with the localization and function of the RNA-binding protein Rbfox2. A study led by Kee Kim at Chungnam National University and Su-Hyung Park at Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea, showed that in human colon cancer cells Rbfox2 is located in the cytoplasm where it promotes cell proliferation by blocking the assembly of the tumor suppressor protein RB1. Treatment with resveratrol prevented the migration of Rbfox2 from the nucleus to the cytoplasm and significantly reduced tumor growth in a mouse model of melanoma. This study not only sheds light on the protective effects of resveratrol but also suggests that Rbfox2 could be a potential target for the development of new anticancer drugs.

Agro-Industrial By-Products and Their Bioactive Compounds—An Ally against Oxidative Stress and Skin Aging

The increased consumer awareness towards hazards related with sun exposure has given a boost in the cosmetics industry and particularly the sun care market. Human skin is continually being threatened by the UV irradiation present in sunlight and acute UV exposure leads to skin photoaging. Cosmetic and/or dermatological applications include several bioactive compounds that contribute to the regulation of epidermal homeostasis by providing protection against solar radiation and improving the antioxidant activity of epidermis. Plant extracts are sources of active ingredients with intense therapeutic properties, and the topical application or oral intake of these compounds could ameliorate skin condition. Nowadays, there is a growing demand for the application of the bioactive agents contained in agro-industrial byproducts in sun care products, since many of them have shown promising properties as skin photoprotectants. However, well-conducted clinical studies are required to prove their safety and efficacy before they could be regularly used. Environmentally friendly extraction and sustainable techniques are therefore under examination for recovering such compounds from agro-industrial byproducts and converting them into innovative high-value natural ingredients used in cosmetic formulations.

Phytochemicals for the Prevention of Photocarcinogenesis

Ultraviolet (UV) exposure has an array of damaging effects and is the main cause of skin cancer in humans. Nonmelanoma skin cancer (NMSC), including basal cell carcinoma and squamous cell carcinoma, is the most common type of cancer. Incidence of NMSC has increased due to greater UV radiation, increased life expectancy and other changes in lifestyle; the annual cost of skin cancer treatment in the United States has increased concurrently to around eight billion dollars. Because of these trends, novel approaches to skin cancer prevention have become an important area of research to decrease skin cancer morbidity and defray the costs associated with treatment. Chemoprevention aims to prevent or delay the development of skin cancer through the use of phytochemicals. Use of phytochemicals as chemopreventive agents has gained attention due to their low toxicity and anticarcinogenic properties. Phytochemicals also exhibit antioxidant, anti-inflammatory and antiproliferative effects which support their use as chemopreventive agents, particularly for skin cancer. Preclinical and human studies have shown that phytochemicals decrease UV-induced skin damage and photocarcinogenesis. In this review article, we discuss the selected phytochemicals that may prevent or delay UV-induced carcinogenesis and highlight their potential use for skin protection.

Engineering yeast for high-level production of stilbenoid antioxidants

Stilbenoids, including resveratrol and its methylated derivatives, are natural potent antioxidants, produced by some plants in trace amounts as defense compounds. Extraction of stilbenoids from natural sources is costly due to their low abundance and often limited availability of the plant. Here we engineered the yeast Saccharomyces cerevisiae for production of stilbenoids on a simple mineral medium typically used for industrial production. We applied a pull-push-block strain engineering strategy that included overexpression of the resveratrol biosynthesis pathway, optimization of the electron transfer to the cytochrome P450 monooxygenase, increase of the precursors supply, and decrease of the pathway intermediates degradation. Fed-batch fermentation of the final strain resulted in a final titer of 800 mg l⁻¹ resveratrol, which is by far the highest titer reported to date for production of resveratrol from glucose. We further integrated heterologous methyltransferases into the resveratrol platform strain and hereby demonstrated for the first time de novo biosynthesis of pinostilbene and pterostilbene, which have better stability and uptake in the human body, from glucose.

A Comprehensive Review on the Chemotherapeutic Potential of Piceatannol for Cancer Treatment, with Mechanistic Insights

Cancer is a diverse class of diseases characterized by uncontrolled cell growth that constitutes the greatest cause of mortality and morbidity worldwide. Despite steady progress, the treatment modalities of cancer are still insufficient. Several new concepts have emerged for therapeutic intervention in malignant diseases with the goal of identifying specific targets and overcoming resistance against current cytotoxic therapies. Many studies have reported the remarkable and significant properties of dietary plant polyphenols such as curcumin, resveratrol, flavopiridol, indirubin, magnolol, piceatannol, parthenolide, epigallocatechin gallate, and cucurbitacin as anticancer agents known for their pleiotropic effects on cancer, immune cells, and inflammation. Piceatannol, an analogue and metabolite of resveratrol, is a natural stilbene commonly found in grape skins and wine. Compared to resveratrol, this molecule exhibits superior bioactivities as an inhibitor of COX-1/2 and the CSN-associated kinase. Piceatannol is thought to be a potent natural compound with many therapeutic effects, such as the prevention of hypercholesterolemia, arrhythmia, atherosclerosis, angiogenesis, and cardiovascular diseases. It also demonstrates vasorelaxation, antioxidant, and anticancer activities. This comprehensive review summarizes the current data regarding the mechanisms of action of piceatannol, its chemopreventive properties, and its possible therapeutic potential against various types of human cancer.

Pleiotropic Role of Dietary Phytochemicals in Cancer: Emerging Perspectives for Combinational Therapy

Cancer is considered a complicated health issue worldwide. The mean cancer survival through standard therapeutic strategies has not been significantly improved over the past few decades. Hence, alternate remedies are needed to treat or prevent this dreadful disease being explored. Currently, it has been recognized that repeated treatment with chemotherapeutic agents has been largely ineffective due to multidrug resistance and further conventional treatment possesses limited drug accessibility to cancerous tissues, which in turn necessitates a higher dose resulting in increased cytotoxicity. Drug combinations have been practiced to address the problems associated with conventional single drug treatment. Recently, natural dietary agents have attracted much attention in cancer therapy because of their synergistic effects with anticancer drugs against different types of cancer. Natural phytochemicals may execute their anticancer activity through targeting diverse cancer cell signaling pathways, promoting cell cycle arrest and apoptosis, regulating antioxidant status and detoxification. This review focuses mainly on the anticancer efficacy of dietary phytochemicals in combination with standard therapeutic drugs reported from various in vitro and in vivo experimental studies apart from clinical trials. This review adds knowledge to the field of intervention studies using combinational modalities that opens a new window for cancer treatment/chemoprevention.

Resveratrol supplementation: Where are we now and where should we go?

Pre-clinical findings have provided mounting evidence that resveratrol, a dietary polyphenol, may confer health benefits and protect against a variety of medical conditions and age-related complications. However, there is no consistent evidence of an increased protection against metabolic disorders and other ailments when comparing studies in laboratory animals and humans. A number of extraneous and potential confounding variables can affect the outcome of clinical research. To date, most of the studies that have investigated the effect of resveratrol administration on patient outcomes have been limited by their sample sizes. In this review, we will survey the latest advances regarding the timing, dosage, formulation, bioavailability, toxicity of resveratrol, and resveratrol-drug interactions in human studies. Moreover, the present report focuses on the actions of resveratrol treatment in combating diseases, such as cancer, diabetes, neurodegeneration, cardiovascular disease, and other age-related ailments.

Shikonin causes cell-cycle arrest and induces apoptosis by regulating the EGFR-NF-κB signalling pathway in human epidermoid carcinoma A431 cells

Shikonin, a naphthoquinone pigment isolated from the Chinese herbal Zicao, has been shown to exhibit antioxidant and anticancer effects. In the present study, we investigated the antiproliferative and pro-apoptotic effects of shikonin on A431 cells and explored the underlying molecular mechanisms. In the present study, our results showed that shikonin significantly inhibited the growth of A431 cells in a concentration- and time-dependent manner, and caused cell cycle arrest by upregulation of p21 and p27, and downregulation of cyclins and cyclin-dependent kinases. In addition, shikonin evidently induced apoptosis due to decreasing Bcl-2 expression, increasing Bax expression, activating caspase and inactivating NF-κB, while pretreatment with a pan-caspase inhibitor Z-Asp-CH2-DCB abrogated shikonin-induced apoptosis. Moreover, EGF could significantly increase the NF-κB DNA-binding activity and reversed the shikonin-induced inactivation of NF-κB. As anticipated AG1478 (EGFR inhibitor) and Bay11-7082 (NF-κB inhibitor) blocked EGF-reversed the inactivation of NF-κB induced by shikonin. Our data also showed that EGF could evidently reverse the shikonin-induced decreases in cell viability and increases in apoptosis. Then, the NF-κB inhibitors such as Bay11-7082, SN50, Helenalin and the EGFR inhibitor AG1478 and its downstream inhibitor such as PI3K inhibitor LY294002 and STAT3 inhibitor Stattic dramatically blocked EGF-reversed decreases in cell viability and increases in apoptosis induced by shikonin. Collectively, our findings indicated that shikonin inhibited cell growth and caused cell cycle arrest of the A431 cells through the regulation of apoptosis. Moreover, these effects were mediated at least partially by suppressing the activation of the EGFR-NF-κB signaling pathways.

MiR-20a inhibits cutaneous squamous cell carcinoma metastasis and proliferation by directly targeting LIMK1

BACKGROUND

MicroRNA-20a (miR-20a) plays a key role in tumorigenesis and progression. But its function is reverse in different kinds of malignant tumor, and its role and mechanism in cutaneous squamous cell carcinoma (CSCC) remains unclear.

OBJECT

To determine the miR-20a's roles in CSCC and confirm whether LIMK1 is a direct target gene of miR-20a.

METHODS

First miR-20a and LIMK1 expression levels were detected in six pairs of CSCC tissues and corresponding normal skin by qRT-PCR. Then MTT assays and colony formation assays were performed to evaluate the impact of miR-20a on cell proliferation. In addition, scratch migration assays and transwell invasion assays were performed to check miR-20a's effect on cell metastasis. Since LIMK1 (LIM kinase-1) was predicted as a target gene of miR-20a, the changes of LIMK1 protein and mRNA were measured by western blot and qRT-RCR methods after miR-20a overexpression. Moreover the dual reporter gene assay was performed to confirm whether LIMK1 is a direct target gene of miR-20a. Finally LIMK1 mRNA and miR-20a in other 30 cases of CSCC pathological specimens were determined and a correlation analysis was evaluated.

RESULTS

The miR-20a significantly low-expressed in CSCC tissues compared with that in matched normal tissues while LIMK1 has a relative higher expression. MiR-20a inhibited A431 and SCL-1 proliferation and metastasis. Both of LIMK1 protein and mRNA levels were downregulated after miR-20a overexpression. The dual reporter gene assays revealed that LIMK1 is a direct target gene of miR-20a. Furthermore, qRT-PCR results of LIMK1 mRNA and miR-20a in 30 cases of CSCC pathological specimens showed miR-20a is inversely correlated with LIMK1 expression.

CONCLUSION

Our study demonstrated that miR-20a is involved in the tumor inhibition of CSCC by directly targeting LIMK1 gene. This finding provides potential novel strategies for therapeutic interventions of CSCC.

Resveratrol and cancer: focus on in vivo evidence

Resveratrol is a naturally occurring polyphenol that provides a number of anti-aging health benefits including improved metabolism, cardioprotection, and cancer prevention. Much of the work on resveratrol and cancer comes from in vitro studies looking at resveratrol actions on cancer cells and pathways. There are, however, comparatively fewer studies that have investigated resveratrol treatment and cancer outcomes in vivo, perhaps limited by its poor bioavailability when taken orally. Although research in cell culture has shown promising and positive effects of resveratrol, evidence from rodents and humans is inconsistent. This review highlights the in vivo effects of resveratrol treatment on breast, colorectal, liver, pancreatic, and prostate cancers. Resveratrol supplementation in animal models of cancer has shown positive, neutral as well as negative outcomes depending on resveratrol route of administration, dose, tumor model, species, and other factors. Within a specific cancer type, there is variability between studies with respect to strain, age, and sex of animal used, timing and method of resveratrol supplementation, and dose of resveratrol used to study cancer endpoints. Together, the data suggest that many factors need to be considered before resveratrol can be used for human cancer prevention or therapy.

Resveratrol couples apoptosis with autophagy in UVB-irradiated HaCaT cells

UVB radiation causes about 90% of non-melanoma skin cancers by damaging DNA either directly or indirectly by increasing levels of reactive oxygen species (ROS). Skin, chronically exposed to both endogenous and environmental pro-oxidant agents, contains a well-organised system of chemical and enzymatic antioxidants. However, increased or prolonged free radical action can overwhelm ROS defence mechanisms, contributing to the development of cutaneous diseases. Thus, new strategies for skin protection comprise the use of food antioxidants to counteract oxidative stress. Resveratrol, a phytoalexin from grape, has gained a great interest for its ability to influence several biological mechanisms like redox balance, cell proliferation, signal transduction pathways, immune and inflammatory response. Therefore, the potential of resveratrol to modify skin cell response to UVB exposure could turn out to be a useful option to protect skin from sunlight-induced degenerative diseases. To investigate into this matter, HaCaT cells, a largely used model for human skin keratinocytes, were treated with 25 or 100 µM resveratrol for 2 and 24 hours prior to UVB irradiation (10 to 100 mJ/cm²). Cell viability and molecular markers of proliferation, oxidative stress, apoptosis, and autophagy were analyzed. In HaCaT cells resveratrol pretreatment: reduces UVB-induced ROS formation, enhances the detrimental effect of UVB on HaCaT cell vitality, increases UVB-induced caspase 8, PARP cleavage, and induces autophagy. These findings suggest that resveratrol could exert photochemopreventive effects by enhancing UVB-induced apoptosis and by inducing autophagy, thus reducing the odds that damaged cells could escape programmed cell death and initiate malignant transformation.

Polydatin, a natural precursor of resveratrol, induces β-defensin production and reduces inflammatory response

It is well known that human keratinocytes produce the anti-microbial peptide β-defensin 2. Its production is enhanced by pathogenic microorganisms or other environmental stressors. In this study, we evaluated the effect of resveratrol, a polyphenol found in several dietary source as grape seed, and its natural precursor, polydatin on heat-stressed human keratinocytes. By reverse transcription-polymerase chain reaction and enzyme-linked immunoadsorbent assay, we demonstrated that resveratrol used in combination with polydatin was able to modulate interleukin (IL)-6, IL-8 and tumor necrosis factor-alpha gene expression. In addition, our data show that resveratrol and polydatin increased the heat shock protein (Hsp)70B' gene expression, a Hsp that plays an important role in the cytoprotection and repair of cells and tissues. Worthy of note, polydatin used alone or in combination with resveratrol, increased the release of human β-defensin 2. These results highlighted the ability of polydatin and resveratrol to reinforce cytoprotective response in stress conditions and suggest their use in cosmetic or pharmaceutical preparations.

Anti-inflammatory effects of concentrated ethanol extracts of Edelweiss (Leontopodium alpinum Cass.) callus cultures towards human keratinocytes and endothelial cells

Edelweiss (Leontopodium alpinum Cass.) is traditionally employed in folk medicine as an anti-inflammatory remedy. In nature, the plant is sparsely available and protected; therefore production of callus cultures was established. A concentrated ethanolic extract of culture homogenate, with leontopodic acid representing 55 ± 2% of the total phenolic fraction (ECC55), was characterized for anti-inflammatory properties in primary human keratinocytes (PHKs) and endotheliocytes (HUVECs). Inflammatory responses were induced by UVA+UVB, lipopolysaccharide (LPS), oxidized low-density lipoprotein (oxLDL), and a mixture of proinflammatory cytokines. Trichostatin A, a sirtuin inhibitor, was used to induce keratinocyte inflammatory senescence. ECC55 (10–50 μg/mL) protected PHK from solar UV-driven damage, by enhancing early intracellular levels of nitric oxide, although not affecting UV-induced expression of inflammatory genes. Comparison of the dose-dependent inhibition of chemokine (IL-8, IP-10, MCP-1) and growth factor (GM-CSF) release from PHK activated by TNFα + IFNγ showed that leontopodic acid was mainly responsible for the inhibitory effects of ECC55. Sirtuin-inhibited cell cycle, proliferation, and apoptosis markers were restored by ECC55. The extract inhibited LPS-induced IL-6 and VCAM1 genes in HUVEC, as well as oxLDL-induced selective VCAM1 overexpression. Conclusion. Edelweiss cell cultures could be a valuable source of anti-inflammatory substances potentially applicable for chronic inflammatory skin diseases and bacterial and atherogenic inflammation.

Resveratrol enhances solar UV-induced responses in normal human epidermal keratinocytes

Resveratrol (RV) differentially affects UV-induced death/pro-survival pathways in normal and tumor cells. On these grounds, RV-containing topical products have been developed to prevent UV-associated tumorigenesis/damage to human skin. In this study, we evaluated mechanisms of combined effects of RV and low-dose solar simulated UVA+UVB or 6-formylindo[3,2-b]carbazole (FICZ), a product of tryptophan photo-oxidation known to mediate UV effects, on the inflammatory, metabolic and proliferative responses of cultured normal human epidermal keratinocytes (HEK). Applied alone, RV, UV and FICZ induced time- and dose-dependent activation of aryl hydrocarbon receptor (AhR) pathway followed by over-expression of Cyp1A1 (metabolic response), UV and RV induced IL-8 expression (inflammatory response), while RV enhanced also HEK proliferation revealed by MTT assay and (3)H-thymidine incorporation. In the combined treatment, RV synergized with both UV and FICZ, leading to further activation of AhR machine, Cyp1A1 transcription and IL-8 expression, the latter partly AhR-dependent as assessed by AhR silencing. RV enhanced UV-induced NFkappaB activation and nuclear translocation of epidermal growth factor receptor. By contrast, proliferative effect of RV was abolished in the presence of UV, whereas synergic anti-proliferative action of RV+UV was observed in the Nrf2-silenced HEK. Our data suggest cooperative effects of RV-specific and UV-/FICZ-activated transcription factors leading to deregulated inflammatory, metabolic and proliferative responses of HEK.

The anticancer effects of resveratrol: modulation of transcription factors

Resveratrol (3, 4', 5-trihydroxystilbene), a naturally occurring phytoalexin readily available in the diet, is reported to possess both chemopreventive and chemotherapeutic activities in several cancers. However, despite the identification of numerous molecular targets, the underlying mechanisms involved in the anticancer activities of resveratrol are not completely understood. Resveratrol is postulated to function as a potential signaling pathway modulator and, as such, is demonstrated to affect a multitude of signal transduction pathways associated with tumorigenesis and/or carcinogenesis; it is likely that this collective activity, rather than just a single effect, may play an important role in the anticancer properties of resveratrol. Since transcription factors control the expression of many genes, the elucidation of molecular targets of resveratrol involved in transcriptional regulation is necessary to better understand how this dietary phytochemical affects chemopreventive and chemotherapeutic processes. As a result, investigators have increasingly searched for and examined possible targets of resveratrol. In this review, we summarize the current knowledge on molecular targets, specifically transcription factors, that contribute to the observed anticancer effects of resveratrol related to 1) inhibition of carcinogenic activation and induction of carcinogen detoxification, 2) induction of growth arrest and apoptosis, and 3) suppression of proinflammatory signaling pathways related to cancer progression.

The prospective role of plant products in radiotherapy of cancer: a current overview

Treatment of cancer often requires exposure to radiation, which has several limitations involving non-specific toxicity toward normal cells, reducing the efficacy of treatment. Efforts are going on to find chemical compounds which would effectively offer protection to the normal tissues after radiation exposure during radiotherapy of cancer. In this regard, plant-derived compounds might serve as “leads” to design ideal radioprotectors/radiosensitizers. This article reviews some of the recent findings on prospective medicinal plants, phytochemicals, and their analogs, based on both in vitro and in vivo tumor models especially focused with relevance to cancer radiotherapy. Also, pertinent discussion has been presented on the molecular mechanism of apoptotic death in relation to the oxidative stress in cancer cells induced by some of these plant samples and their active constituents.

Combinatorial strategies employing nutraceuticals for cancer development

Cancer is the second leading cause of death worldwide. Therefore, the fight against cancer is one of the most important areas of research in medicine, and one that possibly contributes to the increased interest in chemoprevention as an alternative approach to the control of cancer. Cancer prevention by nutraceuticals present in fruits and vegetables has received considerable attention because of their low cost and wide safety margin. A substantial amount of evidence from human, animal, and cell culture studies has shown cancer chemopreventive effects from these natural products. However, single-agent intervention has failed to produce the expected outcome in clinical trials; therefore, combinations of nutraceuticals are gaining increasing popularity. Thus, combinations of nutraceuticals that mimic real-life situations and are competent in targeting multiple targets with very little or virtually no toxicity are needed. In this review, we summarize the results of those studies that report combinatorial cancer chemopreventive action of various nutraceuticals and their combinations with anticancer drugs.

Red raspberries have antioxidant effects that play a minor role in the killing of stomach and colon cancer cells

Berries and berry extracts possess properties that make them important in the prevention of cancer. The high antioxidant levels of these extracts play a role, but components of the berries can have other effects on cell replication and survival. We chose to test the hypothesis that (i) although the antioxidant capacity of raspberry extracts is important for inhibiting the proliferation of tumor cells, other characteristics of the berry extracts are responsible for a major part of their antiproliferative activity, and that (ii) the relative importance of the antioxidant effect can depend on the cell type being studied. The aim of this study was to assess the relative roles of low pH and high antioxidant levels in the killing of 3 cell types by an aqueous extract from Meeker red raspberries. Stomach, colon, and breast cancer cells were treated with berry extract and with HCl and ascorbic acid solutions of the same pH. A dilution of 7.5% ascorbic acid solution, of the same pH and slightly higher antioxidant concentration than the berry extract, killed less than 10% of the stomach and colon cancer cells. In contrast, the berry extract at this same dilution killed more than 90% of these cells. Antioxidants played a more significant role in the killing of breast cancer cells, however. For these cells, approximately 50% of the killing could be attributed to antioxidant effects. We conclude that the antioxidant effect plays a minor role in the killing of 2 gastrointestinal cell types, but its role in inactivating a breast cancer cell line is much more significant. No evidence of apoptosis was observed, and caspase activation did not contribute to cell killing by the extract.

Resveratrol and cellular mechanisms of cancer prevention

The use of novel and improved chemopreventive and chemotherapeutic agents for the prevention and treatment of cancer is on the rise. Natural products have always afforded a rich source of such agents. Epidemiological evidence suggests that a higher flavonoid intake is associated with low cancer risk. Accumulating data clearly indicate that the induction of apoptosis is an important component in the chemoprevention of cancer by naturally occurring dietary agents. Resveratrol, a naturally occurring polyphenol, demonstrates pleiotropic health benefits, including antioxidant, anti-inflammatory, antiaging, cardioprotective, and neuroprotective activities. Because of these properties and their wide distribution throughout the plant kingdom, resveratrol is envisioned as a potential chemopreventive/curative agent. Currently, a number of preclinical findings from our lab and elsewhere suggest resveratrol to be a promising natural weapon in the war against cancer. Remarkable progress in elucidating the molecular mechanisms underlying the anticancer properties of resveratrol has been achieved. Here, we focus on some of the myriad pathways that resveratrol targets to exert its chemopreventive role and advocate that resveratrol holds tremendous potential as an efficient anticancer drug of the future.

The grape antioxidant resveratrol for skin disorders: promise, prospects, and challenges

Resveratrol, a phytoalexin antioxidant found in red grapes, has been shown to have both chemopreventive and therapeutic effects against many diseases and disorders, including those of the skin. Studies have shown protective effects of resveratrol against ultraviolet radiation-mediated oxidative stress and cutaneous damages including skin cancer. Because many of the skin conditions stem from ultraviolet radiation and oxidative stress, this antioxidant appears to have promise and prospects against a wide range of cutaneous disorders including skin aging and skin cancers. However, there are a few roadblocks in the way of this promising agent regarding its translation from the bench to the bedside. This review discusses the promise and prospects of resveratrol in the management of skin disorders and the associated challenges.

alpha-Viniferin suppresses the signal transducer and activation of transcription-1 (STAT-1)-inducible inflammatory genes in interferon-gamma-stimulated macrophages

alpha-Viniferin, an oligostilbene of trimeric resveratrol, has been reported to have anti-inflammatory potential in carrageenin-induced paw edema or adjuvant-induced arthritis in animal models. However, little is known about the molecular basis. In this study, alpha-viniferin at 3 - 10 microM dose-dependently inhibited interferon (IFN)-gamma-induced Ser(727) phosphorylation of the signal transducer and activation of transcription-1 (STAT-1), a pivotal transcription factor controlling IFN-gamma-targeted genes, in RAW 264.7 macrophages, and also IFN-gamma-induced activation of the extracellular signal-regulated kinase (ERK)-1, a protein kinase upstream of the Ser(727) phosphorylation of STAT-1. However, alpha-viniferin, only at a higher concentration of 10 microM, inhibited Janus kinase 2-mediated Tyr(701) phosphorylation of STAT-1 in the cells. To understand STAT-1-dependent inflammatory responses, we quantified nitric oxide (NO) or chemokines. alpha-Viniferin at 3 - 10 muM dose-dependently inhibited IFN-gamma-induced production of NO, IFN-gamma-inducible protein-10 (IP-10), or the monokine induced by IFN-gamma (MIG) in RAW 264.7 cells and also that of NO in primary macrophages-derived from C57BL/6 mice. Furthermore, alpha-viniferin diminished IFN-gamma-induced protein levels of inducible NO synthase (iNOS), attenuated mRNA levels of iNOS, IP-10, or MIG as well as inhibited promoter activity of the iNOS gene. In conclusion, this study proposes an anti-inflammatory mechanism of alpha-viniferin, down-regulating STAT-1-inducible inflammatory genes via inhibiting ERK-mediated STAT-1 activation in IFN-gamma-stimulated macrophages.