Resveratrol regulates p66Shc activation in HaCaT cells

Molecular mechanisms of resveratrol as chemo and radiosensitizer in cancer

One of the primary diseases that cause death worldwide is cancer. Cancer cells can be intrinsically resistant or acquire resistance to therapies and drugs used for cancer treatment through multiple mechanisms of action that favor cell survival and proliferation, becoming one of the leading causes of treatment failure against cancer. A promising strategy to overcome chemoresistance and radioresistance is the co-administration of anticancer agents and natural compounds with anticancer properties, such as the polyphenolic compound resveratrol (RSV). RSV has been reported to be able to sensitize cancer cells to chemotherapeutic agents and radiotherapy, promoting cancer cell death. This review describes the reported molecular mechanisms by which RSV sensitizes tumor cells to radiotherapy and chemotherapy treatment.

HS‑1793 inhibits cell proliferation in lung cancer by interfering with the interaction between p53 and MDM2

The transcription factor or tumor suppressor protein p53 regulates numerous cellular functions, including cell proliferation, invasion, migration, senescence and apoptosis, in various types of cancer. HS-1793 is an analog of resveratrol, which exhibits anti-cancer effects on various types of cancer, including breast, prostate, colon and renal cancer, and multiple myeloma. However, to the best of our knowledge, the role of HS-1793 in lung cancer remains to be examined. The present study aimed to investigate the anti-cancer effect of HS-1793 on lung cancer and to determine its association with p53. The results revealed that HS-1793 reduced cell proliferation in lung cancer and increased p53 stability, thereby elevating the expression levels of the target genes p21 and mouse double minute 2 homolog (MDM2). When the levels of MDM2, a negative regulator of p53, are increased under normal conditions, MDM2 binds and degrades p53; however, HS-1793 inhibited this binding, confirming that p53 protein stability was increased. In conclusion, the findings of the present study provide new evidence that HS-1793 may inhibit lung cancer proliferation by disrupting the p53-MDM2 interaction.

Antioxidant Activity of Resveratrol Diastereomeric Forms Assayed in Fluorescent-Engineered Human Keratinocytes

Resveratrol is a powerful antioxidant molecule. In the human diet, its most important source is in Vitis vinifera grape peel and leaves. Resveratrol exists in two isoforms, cis- and trans. The diastereomeric forms of many drugs have been reported as affecting their activity. The aim of this study was to set up a cellular model to investigate how far resveratrol could counteract cytotoxicity in an oxidant agent. For this purpose, a keratinocyte cell line, which was genetically engineered with jelly fish green fluorescent protein, was treated with the free radical promoter Cumene hydroperoxide. The antioxidant activity of the trans-resveratrol and its diastereomeric mixture was evaluated indirectly in these treated fluorescent-engineered keratinocytes by analyzing the cell number and cell proliferation index. Our results demonstrate that cells, which were pre-incubated with resveratrol, reverted the oxidative damage progression induced by this free radical agent. In conclusion, fluorescent-engineered human keratinocytes represent a rapid and low-cost cellular model to determine cell numbers by studying emitted fluorescence. Comparative studies carried out with fluorescent keratinocytes indicate that trans-resveratrol is more efficient than diastereomeric mixtures in protecting cells from the oxidative stress.

miR-412-5p targets Xpo1 to regulate angiogenesis in hemorrhoid tissue

Hemorrhoid is a common and recurrent proctological disease, which is often accompanied by angiogenesis and edema. MicroRNAs in the DLK1-DIO3 imprinted clusters are involved in the development and pathogenesis of mammalian hemorrhoids. Results of the present study indicated multiple, differential expression of DLK1-DIO3 imprinted cluster microRNA between hemorrhoid and normal tissues, where miR-412-5p expression in hemorrhoid tissue was significantly decreased. Fluorescein reporter assays showed that miR-412-5p silenced Xpo1 mRNA expression by targeting its 3'-UTR. Overexpression of miR-412-5p in human umbilical vein endothelial cells (HUVECs) indicated that proliferation, migration and formation of vascular structures in HUVECs were inhibited in vitro. In addition, overexpression of miR-412-5p significantly inhibited Xpo1 expression and promoted upregulation of the p53 protein and its retention in the nucleus. Simultaneously, expression of p66SHC and p16 proteins was activated. In summary, downregulation of endogenous miR-412-5p expression in hemorrhoid vascular endothelial cells leads to high expression of the target gene Xpo1 and translocation of the p53 protein out of the nucleus, rendering it unable to activate p66SHC and p16. This ultimately weakens regulation of the vascular endothelial cell cycle, thereby accelerating the division of hemorrhoid vascular endothelial cells, leading to angiogenesis.

New aspects of p66Shc in ischaemia reperfusion injury and other cardiovascular diseases

Although reactive oxygen species (ROS) act as crucial factors in the onset and progression of a wide array of diseases, they are also involved in numerous signalling pathways related to cell metabolism, growth and survival. ROS are produced at various cellular sites, and it is generally agreed that mitochondria generate the largest amount, especially those in cardiomyocytes. However, the identification of the most relevant sites within mitochondria, the interaction among the various sources, and the events responsible for the increase in ROS formation under pathological conditions are still highly debated, and far from being clarified. Here, we review the information linking the adaptor protein p66Shc with cardiac injury induced by ischaemia and reperfusion (I/R), including the contribution of risk factors, such as metabolic syndrome and ageing. In response to several stimuli, p66Shc migrates into mitochondria where it catalyses electron transfer from cytochrome c to oxygen resulting in hydrogen peroxide formation. Deletion of p66Shc has been shown to reduce I/R injury as well as vascular abnormalities associated with diabetes and ageing. However, p66Shc-induced ROS formation is also involved in insulin signalling and might contribute to self-endogenous defenses against mild I/R injury. In addition to its role in physiological and pathological conditions, we discuss compounds and conditions that can modulate the expression and activity of p66Shc.

LINKED ARTICLES

This article is part of a themed section on Redox Biology and Oxidative Stress in Health and Disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.12/issuetoc.

Cyclophosphamide promotes the proliferation inhibition of mouse ovarian granulosa cells and premature ovarian failure by activating the lncRNA-Meg3-p53-p66Shc pathway

The dysfunction of ovarian granulosa cells (OGCs) directly affects the premature ovarian failure (POF). In vivo experiments showed that cyclophosphamide significantly induced mouse ovarian atrophy and proliferation inhibition of OGCs. The expressions of p53, p66Shc and p16 were significantly higher in OGCs of the cyclophosphamide treatment group. MTT assay showed that cyclophosphamide effectively inhibited the proliferation of OGCs in vitro. SA-β-Gal staining showed that the OGCs in the cyclophosphamide treatment group had many senescent cells. And, the expression of p53, p66Shc, p16 and cleaved caspase-3 in the OGCs of the cyclophosphamide treatment group significant increases. The Northern blot showed that the intensity of the lncRNA-Meg3 hybridization signal of the OGCs in the cyclophosphamide treatment group was significantly higher than that in the control group. ChIP results confirmed the significant increase in the obtained p66Shc promoter DNA fragment, which was enriched on p53 protein, in the OGCs treated with cyclophosphamide. When cyclophosphamide treatment was conducted after siRNA-Meg3 was used, the expression of endogenous lncRNA-Meg3, p53, p66Shc, p16 and cleaved caspase-3 was significantly lower than that in the siRNA-Mock control group. In summary, cyclophosphamide promotes the proliferation inhibition of mouse OGCs and premature ovarian failure by activating the lncRNA-Meg3-p53-p66Shc pathway.

Convergent Effects of Resveratrol and PYK2 on Prostate Cells

Resveratrol, a dietary polyphenol, is under consideration as chemopreventive and chemotherapeutic agent for several diseases, including cancer. However, its mechanisms of action and its effects on non-tumor cells, fundamental to understand its real efficacy as chemopreventive agent, remain largely unknown. Proline-rich tyrosine kinase 2 (PYK2), a non-receptor tyrosine kinase acting as signaling mediator of different stimuli, behaves as tumor-suppressor in prostate. Since, PYK2 and RSV share several fields of interaction, including oxidative stress, we have investigated their functional relationship in human non-transformed prostate EPN cells and in their tumor-prone counterpart EPN-PKM, expressing a PYK2 dead-kinase mutant. We show that RSV has a strong biological activity in both cell lines, decreasing ROS production, inducing morphological changes and reversible growth arrest, and activating autophagy but not apoptosis. Interestingly, the PYK2 mutant increases basal ROS and autophagy levels, and modulates the intensity of RSV effects. In particular, the anti-oxidant effect of RSV is more potent in EPN than in EPN-PKM, whereas its anti-proliferative and pro-autophagic effects are more significant in EPN-PKM. Consistently, PYK2 depletion by RNAi replicates the effects of the PKM mutant. Taken together, our results reveal that PYK2 and RSV act on common cellular pathways and suggest that RSV effects on prostate cells may depend on mutational-state or expression levels of PYK2 that emerges as a possible mediator of RSV mechanisms of action. Moreover, the observation that resveratrol effects are reversible and not associated to apoptosis in tumor-prone EPN-PKM cells suggests caution for its use in humans.

Resveratrol: challenges in analyzing its biological effects

Testing the biological activities of a dietary compound like resveratrol presents various challenges, which are highlighted in this commentary, with some suggested direction for future research, focusing on five challenges: (1) many different cellular effects are observed for resveratrol, but it is not known whether they arise from one point of action (or a few) or whether resveratrol is non-specific in its action; (2) the health-promotion effect of dietary resveratrol is likely a combinatory effect of various bioactive components in the mixture (diet); (3) the known cell biological response to resveratrol is presently based on exposure to short-term high levels, and better in vitro analyses have to be developed; (4) the actual level of resveratrol and resveratrol metabolites present in vitro and in vivo during experiments may be over- and underestimated, respectively, because resveratrol is not very soluble in water; and (5) only a few small clinical studies have been published to date, focusing on the therapeutic effects of resveratrol. Further, clinical trials addressing the disease-preventive effects are especially challenging.

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.

P66Shc-rac1 pathway-mediated ROS production and cell migration is downregulated by ascorbic acid

The oxidative role(s) of p66Shc protein has been increasingly expanded over the last decade. However, its relation with the most potent antioxidant molecule, i.e. ascorbic acid has never been studied. We have previously shown that p66Shc mediates rac1 activation, reactive oxygen species (ROS) production and cell death. Here we studied the effect of ascorbic acid on the pathway involving p66Shc and rac1. Our results indicate a decrease in the expression of p66Shc in a dose- and time-dependent manner. We studied the effect of ascorbic acid on rac1 expression and its activity. Ascorbic acid has no effect on total rac1 expression; however, rac1 activation was inhibited in a dose-dependent manner. Results suggest that the decrease in rac1 activity is mediated through ascorbic acid-modulated p66Shc expression. The decrease in rac1 activity was evident in cells transfected with the p66shc mutant (proline motif mutant, at residues P47 to P50). Our studies indicate that p66Shc-mediated ROS upregulation is significantly decreased in the presence of ascorbic acid. Cell migration experiments point towards the inhibition of p66Shc-rac1-mediated migration in the presence of ascorbic acid. Finally, results are suggestive that ascorbic acid-mediated decrease in Shc expression occurs through an increased Shc ubiquitination. Overall, the study brings out the novel role of ascorbic acid in antioxidant signal transduction.

Different characteristics of reactive oxygen species production by human keratinocyte cell line cells in response to allergens and irritants

Keratinocytes mount immune responses through the secretion of a variety of inflammatory cytokines, soluble proteins and reactive oxygen species (ROS). However, the role of ROS in keratinocytes in response to allergens and irritants has not yet been elucidated. In this study, we investigated the (i) ROS production; (ii) potential sites of ROS production; (iii) expression of cell surface molecules; (iv) secretion of cytokines; and (v) ROS-dependent protein carbonylation in chemical-treated human keratinocyte cell line (HaCaT) cells. Treatment of HaCaT cells with 2,4-dinitrochlorobenzene (DNCB) and benzalkonium chloride (BKC) increased ROS levels in a time- and dose-dependent manner, as determined with dichlorodihydrofluorescein diacetate (CM-H(2) DCFDA), without reducing cell viability. Potential sources of ROS production were evaluated with pretreatment of diphenylene iodonium (DPI), an inhibitor of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase; rotenone, an inhibitor of the mitochondrial electron transport chain complex or allopurinol, a xanthine oxidase inhibitor. The DNCB-induced ROS was related to both NADPH oxidase and mitochondrial electron transport chain complex. Conversely, BKC-induced ROS was related to NADPH oxidase only. Western blotting using an anti-DNP antibody revealed ROS-dependent protein carbonylation in response to DNCB but not BKC. Both DNCB and BKC increased the secretion of IL-1α from HaCaT cells; however, ROS production as well as other changes, except DNCB-induced secretion of IL-1α, was not inhibited by antioxidants. Although the role of ROS in keratinocytes in response to chemicals was inconclusive, our results suggest that the characteristics of ROS produced by keratinocytes in response to chemicals might differ.

Resveratrol-containing gel for the treatment of acne vulgaris: a single-blind, vehicle-controlled, pilot study

BACKGROUND

Acne vulgaris is a complex, chronic, and common skin disorder of pilosebaceous units. The major pathogenic factors involved are ductal hyperkeratinization, obstruction of sebaceous follicles resulting from abnormal keratinization of the infundibular epithelium, stimulation of sebaceous gland secretion by androgens, and microbial colonization of pilosebaceous units by Propionibacterium acnes, which promotes perifollicular inflammation.

AIM

The aim of the study was to investigate the therapeutic effects of resveratrol, a natural phytoalexin produced by some spermatophytes, such as grapes and other plants, on acneic skin.

METHODS

Resveratrol was incorporated in a carboxymethylcellulose-based gel. The chemical stability of resveratrol after storage at 4°C for 30 days was investigated by high-performance liquid chromatography (HPLC). The resveratrol-containing hydrogel was administered to 20 patients affected by acne vulgaris enrolled in this single-blind study. The resveratrol-containing formulation was applied daily as a solo treatment on the right side of the face for 60 days, while the hydrogel vehicle was applied to the left side of the face as a control. To objectively evaluate the results, a digital photographic database was used to collect images. The number and type of lesions were recorded for each patient, to compare the Global Acne Grading System (GAGS) score before treatment with that obtained at the end of the study. Moreover, with the innovative technique of follicular biopsy, areas of acneic skin were prepared for histopathology. The average area occupied by microcomedones at baseline was compared with that at the end of treatment.

RESULTS

HPLC analysis demonstrated that resveratrol, upon incorporation into the gel, did not convert to its cis-isomer when stored at 4°C for 30 days. All patients were satisfied with the active treatment and none experienced adverse effects. Clinical evaluation showed a 53.75% mean reduction in the GAGS score on the resveratrol-treated sides of the face compared with 6.10% on the vehicle-treated sides of the face. These data were supported by histologic analysis, which showed a 66.7% mean reduction in the average area of microcomedones on the resveratrol-treated sides of the face. The comparison with the vehicle-treated side of the face (9.7% reduction) showed a clinically relevant and statistically significant decrease of lesions in areas treated with resveratrol-containing hydrogel.

CONCLUSION

This pilot study showed positive results for resveratrol gel in acne, and should be considered a valid starting point for further testing of the effectiveness of this molecule in different concentrations and formulations and in a larger group of patients.

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.

Resveratrol enhances antitumor activity of TRAIL in prostate cancer xenografts through activation of FOXO transcription factor

BACKGROUND

Resveratrol (3, 4', 5 tri-hydroxystilbene), a naturally occurring polyphenol, exhibits anti-inflammatory, antioxidant, cardioprotective and antitumor activities. We have recently shown that resveratrol can enhance the apoptosis-inducing potential of TRAIL in prostate cancer cells through multiple mechanisms in vitro. Therefore, the present study was designed to validate whether resveratrol can enhance the apoptosis-inducing potential of TRAIL in a xenograft model of prostate cancer.

METHODOLOGY/PRINCIPAL FINDINGS

Resveratrol and TRAIL alone inhibited growth of PC-3 xenografts in nude mice by inhibiting tumor cell proliferation (PCNA and Ki67 staining) and inducing apoptosis (TUNEL staining). The combination of resveratrol and TRAIL was more effective in inhibiting tumor growth than single agent alone. In xenografted tumors, resveratrol upregulated the expressions of TRAIL-R1/DR4, TRAIL-R2/DR5, Bax and p27(/KIP1), and inhibited the expression of Bcl-2 and cyclin D1. Treatment of mice with resveratrol and TRAIL alone inhibited angiogenesis (as demonstrated by reduced number of blood vessels, and VEGF and VEGFR2 positive cells) and markers of metastasis (MMP-2 and MMP-9). The combination of resveratrol with TRAIL further inhibited number of blood vessels in tumors, and circulating endothelial growth factor receptor 2-positive endothelial cells than single agent alone. Furthermore, resveratrol inhibited the cytoplasmic phosphorylation of FKHRL1 resulting in its enhanced activation as demonstrated by increased DNA binding activity.

CONCLUSIONS/SIGNIFICANCE

These data suggest that resveratrol can enhance the apoptosis-inducing potential of TRAIL by activating FKHRL1 and its target genes. The ability of resveratrol to inhibit tumor growth, metastasis and angiogenesis, and enhance the therapeutic potential of TRAIL suggests that resveratrol alone or in combination with TRAIL can be used for the management of prostate cancer.