Resveratrol promotes oxidative stress to drive DLC1 mediated cellular senescence in cancer cells

Nanocarriers for natural polyphenol senotherapeutics

Senescence is a heterogenous and dynamic process in which various cell types undergo cell-cycle arrest due to cellular stressors. While senescence has been implicated in aging and many human pathologies, therapeutic interventions remain inadequate due to the absence of a comprehensive set of biomarkers in a context-dependent manner. Polyphenols have been investigated as senotherapeutics in both preclinical and clinical settings. However, their use is hindered by limited stability, toxicity, modest bioavailability, and often inadequate concentration at target sites. To address these limitations, nanocarriers such as polymer nanoparticles and lipid vesicles can be utilized to enhance the efficacy of senolytic polyphenols. Focusing on widely studied senolytic agents-specifically fisetin, quercetin, and resveratrol-we provide concise summaries of their physical and chemical properties, along with an overview of preclinical and clinical findings. We also highlight common signaling pathways and potential toxicities associated with these agents. Addressing challenges linked to nanocarriers, we present examples of senotherapeutic delivery to various cell types, both with and without nanocarriers. Finally, continued research and development of senolytic agents and nanocarriers are encouraged to reduce the undesirable effects of senescence on different cell types and organs. This review underscores the need for establishing reliable sets of senescence biomarkers that could assist in evaluating the effectiveness of current and future senotherapeutic candidates and nanocarriers.

Bioactive compounds from nature: Antioxidants targeting cellular transformation in response to epigenetic perturbations induced by oxidative stress

Oxidative stress results from a persistent imbalance in oxidation levels that promotes oxidants, playing a crucial role in the early and sustained phases of DNA damage and genomic and epigenetic instability, both of which are intricately linked to the development of tumors. The molecular pathways contributing to carcinogenesis in this context, particularly those related to double-strand and single-strand breaks in DNA, serve as indicators of DNA damage due to oxidation in cancer cases, as well as factors contributing to epigenetic instability through ectopic expressions. Oxidative stress has been considered a therapeutic target for many years, and an increasing number of studies have highlighted the promising effectiveness of natural products in cancer treatment. In this regard, we present significant research on the therapeutic targeting of oxidative stress using natural molecules and underscore the essential role of oxidative stress in cancer. The consequences of stress, especially epigenetic instability, also offer significant therapeutic prospects. In this context, the use of natural epi-drugs capable of modulating and reorganizing the epigenetic network is beginning to emerge remarkably. In this review, we emphasize the close connections between oxidative stress, epigenetic instability, and tumor transformation, while highlighting the role of natural substances as antioxidants and epi-drugs in the anti-tumoral context.

Resveratrol induces the production of reactive oxygen species, interferes with the cell cycle, and inhibits the cell migration of bladder tumour cells with different TP53 status

Resveratrol is a polyphenolic compound whose antitumor activity has been demonstrated in several types of cancer. However, there are few studies on its molecular mechanisms of action in bladder cancer. Therefore, we aimed to evaluate resveratrol activity in bladder tumour cells with different TP53 gene status. Cytotoxicity, cell proliferation, reactive oxygen species (ROS) production, cell migration, mutagenicity, and CDH1, CTNNBIP1, HAT1, HDAC1, MYC, and SMAD4 gene expression were evaluated. An increase in ROS after resveratrol treatment was accompanied by reduced cell viability and proliferation in all cell lines. In TP53 wild-type cells, the inhibition of cell migration was accompanied by CDH1 and SMAD4 modulation. In TP53 mutated cells, cell migration inhibition with CDH1 and CTNNB1P1 upregulation was observed. In conclusion, resveratrol has antiproliferative effect in bladder tumour cells and its mechanism of action occurred through ROS production, interference with cell cycle, and inhibition of cell migration, independent of TP53 status.

Roles of MT-ND1 in Cancer

The energy shift toward glycolysis is one of the hallmarks of cancer. Complex I is a vital enzyme complex necessary for oxidative phosphorylation. The mitochondrially encoded NADH: ubiquinone oxidoreductase core subunit 1 (MT-ND1) is the largest subunit coded by mitochondria of complex I. The present study summarizes the structure and biological function of MT-ND1. From databases and literature, the expressions and mutations of MT-ND1 in a variety of cancers have been reviewed. MT-ND1 may be a biomarker for cancer diagnosis and prognosis. It is also a potential target for cancer therapy.

Resveratrol exhibits diverse anti-cancer activities through epigenetic regulation of E-cadherin and p21 in triple-negative breast cancer cells

BACKGROUND

Triple-negative breast cancer (TNBC) has an aggressive phenotype and poor outcome, however no specific targeted therapy has been established for TNBC lacking germline BRCA1/2 pathogenic variants. To develop a novel therapeutic strategy, we explored the potential of resveratrol (RSV) for TNBC treatment.

METHODS

We investigated the effects of RSV on malignant phenotypes of TNBC cells as well as on apoptosis induced by ABT263, a specific inhibitor of BCL-2 and BCL-xL, using morphological observation, migration assay, β-galactosidase staining, and Hoechst staining. To elucidate the underlying mechanisms of RSV-mediated effects, expression levels and histone acetylation levels of cadherin 1 (CDH1, E-cadherin) and cyclin dependent kinase inhibitor 1A (CDKN1A, p21) were determined by RT-qPCR, western blotting, and chromatin immunoprecipitation. Furthermore, knockdown analysis was conducted to evaluate the involvement of E-cadherin and/or p21 in RSV potentiation on cytotoxic activity of ABT263.

RESULTS

RSV treatment induced epithelial-like cellular morphology and suppressed the migration capacity in MDA-MB-231 and BT-549-Luc TNBC cells. β-galactosidase-positive cells were increased after RSV treatment, indicating the induction of cellular senescence, in MDA-MB-231 cells but not in BT-549-Luc cells. RSV increased the expression and histone acetylation of CDH1 and CDKN1A in both cells. Interestingly, pre-treatment with RSV enhanced the induction of apoptosis in the ABT263-treated MDA-MB-231 and BT-549-Luc cells, and knockdown of CDKN1A decreased ABT263-induced apoptosis in RSV-treated MDA-MB-231 cells.

CONCLUSIONS

RSV represses the metastatic capacity and enhances the cytotoxic activity of ABT263 in TNBC cells. Our results suggested that RSV can potentially be used as a repressor of metastasis or a sensitizer to ABT263 for TNBC treatment via up-regulation of CDH1 and CDKN1A through epigenetic mechanisms.

Effects and mechanism of perinatal nonylphenol exposure on cardiac function and myocardial mitochondria in neonatal rats

BACKGROUND

Nonylphenol (NP) is a common environmental endocrine disruptor that is associated with the development of cardiovascular disease. However, the toxic effect of NP on mitochondria in the heart of offspring to exposed individuals remains exclusive.

OBJECTIVE

To investigate whether perinatal NP exposure causes mitochondrial damage in the hearts of offspring of exposed individuals and determine its mechanism of action through both animal and cell experiments.

METHODS AND RESULTS

For the in vivo experiment, pregnant rats were randomly divided into four groups: the control group (corn oil, C), low dose group (2.5 mg/kg/day, L-NP group), medium dose group (50 mg/kg/day, M-NP group), and high dose group (100 mg/kg/day, H-NP group), with 12 rats in each group. The NP concentration in the hearts of offspring at PND21 and PND90 increased with the increase of the NP dose. Perinatal NP exposure induced a gradual increase in systolic blood pressure in offspring at PND90. In the H-NP group, there was a high degree of inflammatory cell infiltration, myofibril breaks, inconspicuous or absent nuclei, and pink collagen deposition. At PND90, the membrane integrity of mitochondria in the H-NP group was disrupted, the cristae disorder was aggravated, and there was internal lysis with vacuolation. Compared to the control group, the mitochondrial membrane potential of offspring at PND21 and PND90 was decreased in each of the NP exposure groups. NP exposure decreased the activity of mitochondrial respiratory enzyme complex I (CI) and increased the activity of mitochondrial respiratory enzyme complex IV (CIV) in the offspring. At PND21 and PND90, the mRNA and protein expression levels of cardiac mitochondrial PGC-1α, NRF-1, and TFAM decreased with increasing NP dose in a dose-dependent manner. In the in vitro experiment, H9C2 cells were divided into the following four groups: the blank group, RSV group (15 μg/ml), RSV + NP group (15 μg/ml RSV + 120 mmol/L NP), and NP group (120 mmol/L). With increasing NP concentration, the cell survival rate gradually decreased. Compared to the control, the membrane potential was significantly decreased in the NP group; the protein expression levels of SIRT1, PGC-1α, NRF-1, and TFAM in the NP group were significantly lower.

CONCLUSION

Perinatal NP exposure caused mitochondrial damage and dysfunction in the offspring of exposed individuals in a dose-dependent manner. This toxic effect may be related to NP-induced mitochondrial pathology in the offspring and the inhibition of both gene and protein expression involved in the PGC-1α/NRF-1/TFAM mitochondrial biogenesis signaling pathway following NP exposure.

Gene network analyses of larvae under different egg-protecting behaviors provide novel insights into immune response mechanisms of Amphioctopus fangsiao

Amphioctopus fangsiao was a representative economic species in cephalopods, which was vulnerable to marine bacteria. Vibrio anguillarum was a highly infectious pathogen that have recently been found to infect A. fangsiao and inhibit its growth and development. There were significant differences in the immune response mechanisms between egg-protected and egg-unprotected larvae. To explore larval immunity under different egg-protecting behaviors, we infected A. fangsiao larvae with V. anguillarum for 24 h and analyzed the transcriptome data about egg-protected and egg-unprotected larvae infected with 0, 4, 12, and 24 h using weighted gene co-expression networks (WGCNA) and protein-protein interaction (PPI) networks. Network analyses revealed a series of immune response processes after infection, and identified six key modules and multiple immune-related hub genes. Meanwhile, we found that ZNF family, such as ZNF32, ZNF160, ZNF271, ZNF479, and ZNF493 might play significant roles in A. fangsiao immune response processes. We first creatively combined WGCNA and PPI network analysis to deeply explore the immune response mechanisms of A. fangsiao larvae with different egg-protecting behaviors. Our results provided further insights into the immunity of V. anguillarum infected invertebrates, and laid the foundation for exploring the immune differences among cephalopods with different egg protecting behaviors.

Syndecan-3 Coregulates Milk Fat Metabolism and Inflammatory Reactions in Bovine Mammary Epithelial Cells through AMPK/SIRT1 Signaling Pathway

Transcriptome sequencing showed that syndecan-3 (SDC3) was differentially expressed in high-fat and low-fat mammary epithelial cells of Chinese Holstein cows. Previous studies found that SDC3 plays an important role in inflammatory diseases and virus infection. However, those studies did not confirm whether or not the functional gene SDC3, which plays an important role in regulating milk fat metabolism, has an effect on susceptibility to breast tissue diseases. Therefore, we studied the effects of SDC3 on milk lipid metabolism and inflammation in bovine mammary epithelial cells (BMECs) and further explored the common regulatory pathway of SDC3 in both. The overexpression of SDC3 increased the contents of triglycerides and cholesterol, reduced the content of non-esterified fatty acids, inhibited the expression of inflammatory factors (IL-6, IL-1β, TNF-α and COX-2), and reduced the production of ROS in BMECs. However, silenced SDC3 had the opposite effect. Further exploring the mechanisms of SDC3, we found that SDC3 upregulated the expression of peroxisome proliferator-activated receptor gamma (PPARG) through the AMPK/SIRT1 signal pathway to promote milk fat synthesis. It also regulated the activation of the NF-κB pathway through the AMPK/SIRT1 signal pathway, reducing the expression of inflammatory factors and ROS production, thus inhibiting the inflammatory response of BMECs. Nuclear factor kappa B subunit 1 (NF-κB p50) was an important target of SDC3 in this process. To sum up, our results showed that SDC3 coregulated milk fat metabolism and inflammation through the AMPK/SIRT1 signaling pathway. This study laid a foundation for the comprehensive evaluation of breeding value based on multi-effect functional genes in dairy cow molecular breeding.

Secretory Factors from Calcium-Sensing Receptor-Activated SW872 Pre-Adipocytes Induce Cellular Senescence and A Mitochondrial Fragmentation-Mediated Inflammatory Response in HepG2 Cells

Adipose tissue inflammation in obesity has a deleterious impact on organs such as the liver, ultimately leading to their dysfunction. We have previously shown that activation of the calcium-sensing receptor (CaSR) in pre-adipocytes induces TNF-α and IL-1β expression and secretion; however, it is unknown whether these factors promote hepatocyte alterations, particularly promoting cell senescence and/or mitochondrial dysfunction. We generated conditioned medium (CM) from the pre-adipocyte cell line SW872 treated with either vehicle (CMveh) or the CaSR activator cinacalcet 2 µM (CMcin), in the absence or presence of the CaSR inhibitor calhex 231 10 µM (CMcin+cal). HepG2 cells were cultured with these CM for 120 h and then assessed for cell senescence and mitochondrial dysfunction. CMcin-treated cells showed increased SA-β-GAL staining, which was absent in TNF-α- and IL-1β-depleted CM. Compared to CMveh, CMcin arrested cell cycle, increased IL-1β and CCL2 mRNA, and induced p16 and p53 senescence markers, which was prevented by CMcin+cal. Crucial proteins for mitochondrial function, PGC-1α and OPA1, were decreased with CMcin treatment, concomitant with fragmentation of the mitochondrial network and decreased mitochondrial transmembrane potential. We conclude that pro-inflammatory cytokines TNF-α and IL-1β secreted by SW872 cells after CaSR activation promote cell senescence and mitochondrial dysfunction, which is mediated by mitochondrial fragmentation in HepG2 cells and whose effects were reversed with Mdivi-1. This investigation provides new evidence about the deleterious CaSR-induced communication between pre-adipocytes and liver cells, incorporating the mechanisms involved in cellular senescence.

Destruction of the cellular antioxidant pool contributes to resveratrol-induced senescence and apoptosis in lung cancer

Resveratrol (RES) has various pharmacological bioactivities and its anticancer effects in lung cancer have been proven. However, the underlying mechanisms of action of RES in lung cancer remain unclear. This study focused on Nrf2-mediated antioxidant systems in RES-treated lung cancer cells. A549 and H1299 cells were treated with various concentrations of RES at different times. RES decreased cell viability, inhibited cell proliferation, and increased the number of senescent and apoptotic cells in a concentration- and time-dependent manner. Moreover, RES-induced lung cancer cell arrest at the G1 phase was accompanied by changes in apoptotic proteins (Bax, Bcl-2, and cleaved caspase 3). Furthermore, RES induced a senescent phenotype along with changes in senescence-related markers (senescence-associated β-galactosidase activity, p21, and p-γH2AX). More importantly, with prolonged exposure time and increased exposure concentration, intracellular reactive oxygen species (ROS) continuously accumulated, resulting in a decrease in Nrf2 and its downstream antioxidant response elements, including CAT, HO-1, NQO1, and SOD1. Meanwhile, RES-induced ROS accumulation and cell apoptosis were reversed by N-acetyl-l-cysteine treatment. Taken together, these results suggest that RES disturb lung cancer cellular homeostasis by destroying the intracellular antioxidant pool to increase ROS production. Our findings provide a new perspective on RES intervention in lung cancer.

Resveratrol induces DNA damage-mediated cancer cell senescence through the DLC1-DYRK1A-EGFR axis

Inducing cell senescence is widely regarded as a potent tumor suppression mechanism. Resveratrol has attracted increasing attention for its capacity to prevent and suppress cancer. However, the mechanism of resveratrol on the induction of cancer cell senescence has not been well clarified. Our results showed that resveratrol inhibited cell viability and colony formation and promoted cell senescence along with augmentation of SA-β-gal activity and modulation of senescence-associated molecular markers p53, p21 and LaminB protein in breast and liver cancer cells. The underlying mechanism was that resveratrol increased ROS generation to enhance tumor suppressor gene DLC1 expression, and DLC1 further inhibited the DYRK1A-EGFR axis to trigger DNA damage accompanied by up-regulation of the DNA double strand break marker protein γH2AX and down-regulation of the DNA repair related proteins p-BRCA1 and RAD51, eventually leading to cancer cell senescence. Resveratrol also effectively inhibited the volume of transplanted tumor with increased SA-β-gal activity and DLC1 level in a chicken embryo allantoic membrane xenograft tumor model. This is the first report to investigate whether resveratrol induces DNA damage-mediated cancer cell senescence through the DLC1-DYRK1A-EGFR axis, which could provide a solid base for resveratrol's application in cancer prevention and clinical treatment as a food additive or adjuvant therapies.

Potential roles and molecular mechanisms of phytochemicals against cancer

Increasing evidence has been reported regarding phytochemicals, plant secondary metabolites, having therapeutic functions against numerous human diseases. Recently, phytochemicals (flavonoids, polyphenols, terpenoids, alkaloids, saponins, coumarins and so on) have shown promising anti-cancer efficacy with their distinct advantages of high efficiency and low toxicity. They regulate programmed cell death (apoptosis, pyroptosis, and autophagy), migration and senescence-related signaling pathways of cancer via the modulation of reactive oxygen species (ROS), mitogen activated protein kinase (MAPK) pathway, deleted in liver cancer 1 (DLC1), nuclear factor κ light-chain-enhancer of activated B cell (NF-κB) pathways and glycolytic enzymes. Here, we review the molecular mechanisms by which phytochemicals prevent the development of cancer. Furthermore, phytochemicals combined with chemotherapeutic agents could target the crosstalk among multiple signal cascades to block chemoresistance and attenuate carcinogenic properties, and can be considered as a novel and potential therapeutic strategy. Our review highlights that the mechanisms and promising applications are required to be understood to decisively establish the anti-cancer efficacy of natural phytochemicals.

The Impact of Oxidative Stress and AKT Pathway on Cancer Cell Functions and Its Application to Natural Products

Oxidative stress and AKT serine-threonine kinase (AKT) are responsible for regulating several cell functions of cancer cells. Several natural products modulate both oxidative stress and AKT for anticancer effects. However, the impact of natural product-modulating oxidative stress and AKT on cell functions lacks systemic understanding. Notably, the contribution of regulating cell functions by AKT downstream effectors is not yet well integrated. This review explores the role of oxidative stress and AKT pathway (AKT/AKT effectors) on ten cell functions, including apoptosis, autophagy, endoplasmic reticulum stress, mitochondrial morphogenesis, ferroptosis, necroptosis, DNA damage response, senescence, migration, and cell-cycle progression. The impact of oxidative stress and AKT are connected to these cell functions through cell function mediators. Moreover, the AKT effectors related to cell functions are integrated. Based on this rationale, natural products with the modulating abilities for oxidative stress and AKT pathway exhibit the potential to regulate these cell functions, but some were rarely reported, particularly for AKT effectors. This review sheds light on understanding the roles of oxidative stress and AKT pathway in regulating cell functions, providing future directions for natural products in cancer treatment.

Exploring the role of senescence inducers and senotherapeutics as targets for anticancer natural products

During the last few decades, cancer has remained one of the deadliest diseases that endanger human health, emphasizing urgent drug discovery. Cellular senescence has gained a great deal of attention in recent years because of its link to the development of cancer therapy. Senescent cells are incapable of proliferating due to irreversibly inhibited the initiation of the cell cycle pathways. However, senescent cells aggregate in tissues and produce a pro-inflammatory secretome called senescence-associated secretory phenotype (SASP) that can cause serious harmful effects if not managed properly. There is mounting evidence that senescent cells lead to various phases of tumorigenesis in various anatomical sites, owing mostly to the paracrine activities of the SASP. Therefore, a new treatment field called senotherapeutics has been established. Senotherapeutics are newly developed anticancer agents that have been demonstrated to inhibit cancer effectively. In light of recent findings, several promising natural products have been identified as senescence inducers and senotherapeutics, including, miliusanes, epigallocatechin gallate, phloretin, silybin, resveratrol, genistein, sulforaphane, quercetin, allicin, fisetin, piperlongumine, berberine, triptolide, tocotrienols and curcumin analogs. Several of them have already been validated through preclinical trials and exert an enormous potential for clinical trials. This review article focuses on and summarises the latest advances on cellular senescence and its potential as a target for cancer treatment and highlights the well-known natural products as senotherapeutics for cancer treatment.

Resveratrol drives cancer cell senescence via enhancing p38MAPK and DLC1 expressions

Pro-senescence therapy is a recently proposed anti-cancer strategy and has been shown to effectively inhibit cancer. Resveratrol is gaining attention for its cancer preventive and suppressive properties. The mechanisms of resveratrol in cancer suppression by inducing cancer cell senescence are unclear. Our results showed that resveratrol induced cell senescence along with an increase of SA-β-Gal activity and inhibition of colony formation in breast and lung cancer cells. The underlying mechanisms were that resveratrol induced ER-stress by increasing SIRT1 to promote p38MAPK expression and by reducing NO level to up-regulate DLC1 expression, and ER-stress further resulted in DNA damage and mitochondrial dysfunction, eventually leading to cancer cell senescence. Our findings on resveratrol's induction of cancer cell senescence via activating ER-stress through the SIRT1/p38MAPK and NO/DLC1 pathways provide a solid base for its clinical application and its preventive application as a food additive.

The Role of Epigenetic Modifications in Human Cancers and the Use of Natural Compounds as Epidrugs: Mechanistic Pathways and Pharmacodynamic Actions

Cancer is a complex disease resulting from the genetic and epigenetic disruption of normal cells. The mechanistic understanding of the pathways involved in tumor transformation has implicated a priori predominance of epigenetic perturbations and a posteriori genetic instability. In this work, we aimed to explain the mechanistic involvement of epigenetic pathways in the cancer process, as well as the abilities of natural bioactive compounds isolated from medicinal plants (flavonoids, phenolic acids, stilbenes, and ketones) to specifically target the epigenome of tumor cells. The molecular events leading to transformation, angiogenesis, and dissemination are often complex, stochastic, and take turns. On the other hand, the decisive advances in genomics, epigenomics, transcriptomics, and proteomics have allowed, in recent years, for the mechanistic decryption of the molecular pathways of the cancerization process. This could explain the possibility of specifically targeting this or that mechanism leading to cancerization. With the plasticity and flexibility of epigenetic modifications, some studies have started the pharmacological screening of natural substances against different epigenetic pathways (DNA methylation, histone acetylation, histone methylation, and chromatin remodeling) to restore the cellular memory lost during tumor transformation. These substances can inhibit DNMTs, modify chromatin remodeling, and adjust histone modifications in favor of pre-established cell identity by the differentiation program. Epidrugs are molecules that target the epigenome program and can therefore restore cell memory in cancerous diseases. Natural products isolated from medicinal plants such as flavonoids and phenolic acids have shown their ability to exhibit several actions on epigenetic modifiers, such as the inhibition of DNMT, HMT, and HAT. The mechanisms of these substances are specific and pleiotropic and can sometimes be stochastic, and their use as anticancer epidrugs is currently a remarkable avenue in the fight against human cancers.

Targeting cellular senescence in cancer by plant secondary metabolites: A systematic review

Senescence suppresses tumor growth, while also developing a tumorigenic state in the nearby cells that is mediated by senescence-associated secretory phenotypes (SASPs). The dual function of cellular senescence stresses the need for identifying multi-targeted agents directed towards the promotion of cell senescence in cancer cells and suppression of the secretion of pro-tumorigenic signaling mediators in neighboring cells. Natural secondary metabolites have shown favorable anticancer responses in recent decades, as some have been found to target the senescence-associated mediators and pathways. Furthermore, phenolic compounds and polyphenols, terpenes and terpenoids, alkaloids, and sulfur-containing compounds have shown to be promising anticancer agents through the regulation of paracrine and autocrine pathways. Plant secondary metabolites are potential regulators of SASPs factors that suppress tumor growth through paracrine mediators, including growth factors, cytokines, extracellular matrix components/enzymes, and proteases. On the other hand, ataxia-telangiectasia mutated, ataxia-telangiectasia and Rad3-related, extracellular signal-regulated kinase/mitogen-activated protein kinase, phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin, nuclear factor-κB, Janus kinase/signal transducer and activator of transcription, and receptor tyrosine kinase-associated mediators are main targets of candidate phytochemicals in the autocrine senescence pathway. Such a regulatory role of phytochemicals on senescence-associated pathways are associated with cell cycle arrest and the attenuation of apoptotic/inflammatory/oxidative stress pathways. The current systematic review highlights the critical roles of natural secondary metabolites in the attenuation of autocrine and paracrine cellular senescence pathways, while also elucidating the chemopreventive and chemotherapeutic capabilities of these compounds. Additionally, we discuss current challenges, limitations, and future research indications.

Polyphenols as anticancer agents: Toxicological concern to healthy cells

Polyphenols are a group of diverse chemical compounds present in a wide range of plants. Various biological properties such as antiallergic, antiviral, antibacterial, anticarcinogenic, antiinflammatory, antithrombotic, vasodilatory, and hepatoprotective effect of different polyphenols have been reported in the scientific literature. The major classes of polyphenols are flavonoids, stilbenoids, lignans, and polyphenolic acids. Flavonoids are a large class of food constituents comprising flavones, isoflavanones, flavanones, flavonols, catechins, and anthocyanins sub-classes. Even with seemingly broad biological activities, their use is minimal clinically. Among the other concurrent problems such as limited bioavailability, rapid metabolism, untargeted delivery, the toxicity associated with these polyphenols has been a topic of concern lately. These polyphenols have been reported to result in different forms of toxicity that include organ toxicity, genotoxicity, mutagenicity, cytotoxicity, etc. In the present article, we have tried to unravel the toxicological aspect of these polyphenols to healthy cells. Further high-quality studies are needed to establish the clinical efficacy and toxicology concern leading to further exploration of these polyphenols.

Identification of potential target genes of non-small cell lung cancer in response to resveratrol treatment by bioinformatics analysis

Non-small cell lung cancer (NSCLC) is the most common type in lung cancer in the world, and it severely threatens the life of patients. Resveratrol has been reported to inhibit cancer. However, mechanisms of resveratrol inhibiting NSCLC were unclear. The aim of this study was to identify differentially expressed genes (DEGs) of NSCLC treated with resveratrol and reveal the potential targets of resveratrol in NSCLC. We obtained mRNA expression profiles of two datasets from the National Center for Biotechnology Information Gene Expression Omnibus (NCBI-GEO) and 271 DEGs were selected for further analysis. Data from STRING shown that 177 nodes and 342 edges were in the protein-protein interaction (PPI) network, and 10 hub genes (ANPEP, CD69, ITGAL, PECAM1, PTPRC, CD34, ITGA1, CCL2, SOX2, and EGFR) were identified by Cytoscape plus-in cytoHubba. Survival analysis revealed that NSCLC patients showing low expression of PECAM1, ANPEP, CD69, ITGAL, and PTPRC were associated with worse overall survival (OS) (P < 0.05), and high expression of SOX2 and EGFR was associated with worse OS for NSCLC patients (P < 0.05). Overall, we identified ANPEP, CD69, ITGAL, and PTPRC as potential candidate genes which were main effects of resveratrol on the treatment of NSCLC. ANPEP, ITGAL, CD69, and PTPRC are all clusters of differentiation (CD) antigens, might be the targets of resveratrol. The bioinformatic results suggested that the inhibitory effect of resveratrol on lung cancer may be related to the immune signaling pathway. Further studies are needed to validate these findings and to explore their functional mechanisms.

Targeting of cancer cell death mechanisms by resveratrol: a review

Cancer cell death is the utmost aim in cancer therapy. Anti-cancer agents can induce apoptosis, mitotic catastrophe, senescence, or autophagy through the production of free radicals and induction of DNA damage. However, cancer cells can acquire some new properties to adapt to anti-cancer agents. An increase in the incidence of apoptosis, mitotic catastrophe, senescence, and necrosis is in favor of overcoming tumor resistance to therapy. Although an increase in the autophagy process may help the survival of cancer cells, some studies indicated that stimulation of autophagy cell death may be useful for cancer therapy. Using some low toxic agents to amplify cancer cell death is interesting for the eradication of clonogenic cancer cells. Resveratrol (a polyphenol agent) may affect various signaling pathways related to cell death. It can induce death signals and also downregulate the expression of anti-apoptotic genes. Resveratrol has also been shown to modulate autophagy and induce mitotic catastrophe and senescence in some cancer cells. This review focuses on the important targets and mechanisms for the modulation of cancer cell death by resveratrol.

Recent Advances in Health Benefits of Stilbenoids

Biological targeting or molecular targeting is the main strategy in drug development and disease prevention. However, the problem of "off-targets" cannot be neglected. Naturally derived drugs are preferred over synthetic compounds in pharmaceutical markets, and the main goals are high effectiveness, lower cost, and fewer side effects. Single-target drug binding may be the major cause of failure, as the pathogenesis of diseases is predominantly multifactorial. Naturally derived drugs are advantageous because they are expected to have multitarget effects, but not off-targets, in disease prevention or therapeutic actions. The capability of phytochemicals to modulate molecular signals in numerous diseases has been widely discussed. Among them, stilbenoids, especially resveratrol, have been well-studied, along with their potential molecular targets, including AMPK, Sirt1, NF-κB, PKC, Nrf2, and PPARs. The analogues of resveratrol, pterostilbene, and hydroxylated-pterostilbene may have similar, if not more, potential biological targeting effects compared with their original counterpart. Furthermore, new targets that have been discussed in recent studies are reviewed in this paper.

ROS Dependent Antifungal and Anticancer Modulations of Piper colubrinum Osmotin

Osmotin, a plant defense protein, has functional similarity to adiponectin, an insulin sensitizingsensitising hormone secreted by adipocytes. We speculated that Piper colubrinum Osmotin (PcOSM) could have functional roles in obesity-related cancers, especially breast cancer. Immunofluorescence assays, flow cytometry, cell cycle analysis and a senescence assay were employed to delineate the activity in MDAMB231 breast cancer cell line. PcOSM pre-treated P. nigrum leaves showed significant reduction in disease symptoms correlated with high ROS production. In silico analysis predicted that PcOSM has higher binding efficiency with adiponectin receptor compared to adiponectin. PcOSM was effectively taken up by MDAMB231 cancer cells which resulted in marked increase in intracellular ROS levels leading to senescence and cell cycle arrest in G2/M stage. This study provides evidence on the ROS mediated direct inhibitory activity of the plant derived osmotin protein on the phytopathogen Phytophthora capsici, and the additional functional roles of this plant defense protein on cancer cells through inducing ROS associated senescence. The strong leads produced from this study could be pursued further to obtain more insights into the therapeutic potential of osmotin in human cancers.

Tumor suppressor gene DLC1: Its modifications, interactive molecules, and potential prospects for clinical cancer application

Deleted in liver cancer 1 (DLC1) is a recognized tumor suppressor gene that negatively regulates Rho family proteins by hydrolyzing the active GTP-bound state to its inactive GDP-bound state. Active Rho proteins play a positive role in tumorigenesis. Numerous in vitro and in vivo experiments have shown that DLC1 is downregulated or inactivated in various solid tumors, which may be due to the following five reasons: genomic deletion, epigenetic modification and ubiquitin-dependent proteasomal degradation may cause DLC1 underexpression; phosphorylation at the post-translation level may cause DLC1 inactivation; and failure to localize at focal adhesions (FAs) may prevent DLC1 from exerting full activity. All of the causes could be attributed to molecular binding. Experimental evidence suggests that direct or indirect targeting of DLC1 is feasible for cancer treatment. Therefore, elucidating the interaction of DLC1 with its binding partners might provide novel targeted therapies for cancer. In this review, we summarized the binding partners of DLC1 at both the gene and protein levels and expounded a variety of anticancer drugs targeting DLC1 to provide information about DLC1 as a cancer diagnostic indicator or therapeutic target.

Flavonoid-rich extracts from okra flowers exert antitumor activity in colorectal cancer through induction of mitochondrial dysfunction-associated apoptosis, senescence and autophagy

Okra flowers contain a higher content of total flavonoids than most other flowers; however little research has been conducted on their potential benefits, including antitumor activity. In this study, we extracted and purified flavonoids from okra flower (AFE), and aimed to evaluate the effect of AFE and its underlying mechanism on colorectal cancer (CRC) cell growth in vitro and in vivo. Here, we identify that AFE is a safe, natural antioxidant and exerts significant antitumor efficacy on the inhibition of CRC cell proliferation and metastasis as well as tumour growth in vivo. We further reveal that AFE inhibits CRC cell proliferation by inducing mitochondrial dysfunction, which results from the activation of p53 and induction of apoptosis and senescence, and inhibits autophagic degradation. Furthermore, AFE inhibited migration and invasion of CRC cells by regulating the balance of MMP2/TIMP2 and MMP9 expression levels. Of note, administration of AFE as a preventive agent achieves a more effective antitumor effect than the therapeutic agent in a xenograft mouse model. Our results reveal, for the first time, that AFE is a safe, natural antioxidant with significant antitumor efficacy, which has great potential in the application for CRC prevention and treatment.

Resveratrol and Tumor Microenvironment: Mechanistic Basis and Therapeutic Targets

Resveratrol (3,4′,5 trihydroxystilbene) is a naturally occurring non-flavonoid polyphenol. It has various pharmacological effects including antioxidant, anti-diabetic, anti-inflammatory and anti-cancer. Many studies have given special attention to different aspects of resveratrol anti-cancer properties and proved its high efficiency in targeting multiple cancer hallmarks. Tumor microenvironment has a critical role in cancer development and progression. Tumor cells coordinate with a cast of normal cells to aid the malignant behavior of cancer. Many cancer supporting players were detected in tumor microenvironment. These players include blood and lymphatic vessels, infiltrating immune cells, stromal fibroblasts and the extracellular matrix. Targeting tumor microenvironment components is a promising strategy in cancer therapy. Resveratrol with its diverse biological activities has the capacity to target tumor microenvironment by manipulating the function of many components surrounding cancer cells. This review summarizes the targets of resveratrol in tumor microenvironment and the mechanisms involved in this targeting. Studies discussed in this review will participate in building a solid ground for researchers to have more insight into the mechanism of action of resveratrol in tumor microenvironment.

Role of Nrf2 in cell senescence regulation

Nuclear factor-E2-related factor 2 (Nrf2) is a key transcription factor known to be involved in maintaining cell redox balance and signal transduction and plays central role in reducing intracellular oxidative stress damage, delaying cell senescence and preventing age-related diseases. However, it has been shown that the level of Nrf2 decreases with age and that the silencing of the Nrf2 gene is associated with the induction of premature senescence. Therefore, a plethora of researchers have focused on elucidating the regulatory mechanism of Nrf2 in the prevention of cell senescence. This complex regulatory mechanism of Nrf2 in the cell senescence process involves coordinated regulation of multiple signaling molecules. After summarizing the function of Nrf2 and its relationship with cell senescence pathway, this review focuses on the recent advances and progress made in elucidating the regulatory mechanism of Nrf2 in the cell senescence process. Additionally, the information collected here may provide insights for further research on Nrf2, in particular, on its regulatory mechanism in the cell senescence process.

The Premature Senescence in Breast Cancer Treatment Strategy

Cellular senescence is a permanent blockade of cell proliferation. In response to therapy-induced stress, cancer cells undergo apoptosis or premature senescence. In apoptosis-resistant cancer cells or at lower doses of anticancer drugs, therapy-induced stress leads to premature senescence. The role of this senescence in cancer treatment is discussable. First of all, the senescent cells lose the ability to proliferate, migrate, and invade. In addition, the senescent cells secrete a set of proteins (inflammatory cytokines, chemokines, growth factors) known as the senescence-associated secretory phenotype (SASP), which influences non-senescent normal cells and non-senescent cancer cells in the tumor microenvironment and triggers tumor promotion and recurrence. Recently, many studies have examined senescence induction through breast cancer therapy and potentially using this phenomenon to treat this cancer. This review summarizes the recent in vitro, in vivo, and clinical studies investigating senescence in breast cancer treatments. Senescence inductors, senolytics, as well as their action mechanism are discussed herein. Potential SASP-modulating treatment strategies are also described.

Combination of Resveratrol and Quercetin Causes Cell Growth Inhibition, DNA Damage, Cell Cycle Arrest, and Apoptosis in Oral Cancer Cells

Resveratrol and quercetin alone are well reported to have anticancer potential, but their combination studies are very inadequate. We have examined their combination in Cal-33 and SCC-15 oral cancer cells (OCCs) and noncancerous HEK-293 cells. Combination of 10 μM concentration of each resveratrol and quercetin brought additive effect on cellular growth, DNA damage, S-phase cell cycle arrest, and cell death in Cal-33 cells but not in the HEK-293 cells. Augmentation of the cell cycle regulatory protein, Cyclin E, and downregulation of Cyclin A possibly caused S-phase arrest in Cal-33 cancer cells. Comet formation and presence of gamma-H2AX foci confirmed DNA damage, and cleavage of PARP1 and upregulation in Bax level specified apoptosis after combined treatment. Ratio of transcription activation and repression histone marks was found increased after alone as well as combined treatment. Histone deacetylase (HDAC)1, HDAC3, and HDAC8 were downregulated by resveratrol alone and combined treatment. Conclusively, combination of resveratrol and quercetin brings cell growth inhibition, DNA damage, and cell cycle arrest in OCCs but not in normal cells. Additionally, combined treatment causes downregulation of HDACs and apoptosis in cancer cells and it could be an incisive strategy against oral cancer.

Metformin activates AMPK/SIRT1/NF-κB pathway and induces mitochondrial dysfunction to drive caspase3/GSDME-mediated cancer cell pyroptosis

Pyroptosis is a form of programmed cell death initiated by inflammasomes and is critical for immunity. SIRT1, a NAD+-dependent deacetylase, plays multiple roles in inflammatory response and immunity. Metformin can activate SIRT1 to participate in different biological processes and exert its anticancer effects. However, the mechanism by which metformin activates SIRT1 to drive cancer cell pyroptosis has not been reported. In this study, we treated cancer cells with metformin for diverse periods of time (0-24 h) and found that cell viability was decreased obviously. Interestingly, pyroptosis occurred when cancer cells were treated with metformin for the indicated time (4, 8 and 12 h), which was elucidated by the cell swelling and bubbles blowing in the membrane. Metformin also increased the release of lactate dehydrogenase (LDH, an indication of pyroptotic cell cytotoxicity) remarkably. The underlying mechanisms were that metformin enhanced AMPK/SIRT1 pathway and further increased NF-κB p65 expression to stimulate Bax activation and cytochrome c release, triggering caspase3 cleavage of GSDME, which is a characteristic pyroptotic marker. Depletion of SIRT1 inhibited metformin-induced these protein expression, revealing that metformin promotes AMPK/SIRT1/NF-κB signaling to drive cancer cell pyroptosis. Meantime, metformin induced mitochondrial dysfunction to trigger activation of caspase3 and generation of GSDME-N. Moreover, mitochondrial dysfunction activated AMPK/SIRT1 pathway to cause pyroptotic death upon metformin treatment. This research firstly reveals that metformin as a sensitizer amplifies AMPK/SIRT1/NF-κB signaling to induce caspase3/GSDME-mediated cancer cell pyroptosis. Induction of cellular pyroptosis by metformin is considered as a novel therapeutic option against various cancers.

Natural products and phytochemical nanoformulations targeting mitochondria in oncotherapy: an updated review on resveratrol

Mitochondria are intracellular organelles with two distinct membranes, known as an outer mitochondrial membrane and inner cell membrane. Originally, mitochondria have been derived from bacteria. The main function of mitochondria is the production of ATP. However, this important organelle indirectly protects cells by consuming oxygen in the route of energy generation. It has been found that mitochondria are actively involved in the induction of the intrinsic pathways of apoptosis. So, there have been efforts to sustain mitochondrial homeostasis and inhibit its dysfunction. Notably, due to the potential role of mitochondria in the stimulation of apoptosis, this organelle is a promising target in cancer therapy. Resveratrol is a non-flavonoid polyphenol that exhibits significant pharmacological effects such as antioxidant, anti-diabetic, anti-inflammatory and anti-tumor. The anti-tumor activity of resveratrol may be a consequence of its effect on mitochondria. Multiple studies have investigated the relationship between resveratrol and mitochondria, and it has been demonstrated that resveratrol is able to significantly enhance the concentration of reactive oxygen species, leading to the mitochondrial dysfunction and consequently, apoptosis induction. A number of signaling pathways such as sirtuin and NF-κB may contribute to the mitochondrial-mediated apoptosis by resveratrol. Besides, resveratrol shifts cellular metabolism from glycolysis into mitochondrial respiration to induce cellular death in cancer cells. In the present review, we discuss the possible interactions between resveratrol and mitochondria, and its potential application in cancer therapy.

Potential Adverse Effects of Resveratrol: A Literature Review

Due to its health benefits, resveratrol (RE) is one of the most researched natural polyphenols. Resveratrol's health benefits were first highlighted in the early 1990s in the French paradox study, which opened extensive research activity into this compound. Ever since, several pharmacological activities including antioxidant, anti-aging, anti-inflammatory, anti-cancerous, anti-diabetic, cardioprotective, and neuroprotective properties, were attributed to RE. However, results from the available human clinical trials were controversial concerning the protective effects of RE against diseases and their sequelae. The reason for these conflicting findings is varied but differences in the characteristics of the enrolled patients, RE doses used, and duration of RE supplementation were proposed, at least in part, as possible causes. In particular, the optimal RE dosage capable of maximizing its health benefits without raising toxicity issues remains an area of extensive research. In this context, while there is a consistent body of literature on the protective effects of RE against diseases, there are relatively few reports investigating its possible toxicity. Indeed, toxicity and adverse effects were reported following consumption of RE; therefore, extensive future studies on the long-term effects, as well as the in vivo adverse effects, of RE supplementation in humans are needed. Furthermore, data on the interactions of RE when combined with other therapies are still lacking, as well as results related to its absorption and bioavailability in the human body. In this review, we collect and summarize the available literature about RE toxicity and side effects. In this process, we analyze in vitro and in vivo studies that have addressed this stilbenoid. These studies suggest that RE still has an unexplored side. Finally, we discuss the new delivery methods that are being employed to overcome the low bioavailability of RE.

Anti-stress, Glial- and Neuro-differentiation Potential of Resveratrol: Characterization by Cellular, Biochemical and Imaging Assays

Environmental stress, exhaustive industrialization and the use of chemicals in our daily lives contribute to increasing incidence of cancer and other pathologies. Although the cancer treatment has revolutionized in last 2–3 decades, shortcomings such as (i) extremely high cost of treatment, (ii) poor availability of drugs, (iii) severe side effects and (iv) emergence of drug resistance have prioritized the need of developing alternate natural, economic and welfare (NEW) therapeutics reagents. Identification and characterization of such anti-stress NEW drugs that not only limit the growth of cancer cells but also reprogram them to perform their specific functions are highly desired. We recruited rat glioma- and human neuroblastoma-based assays to explore such activities of resveratrol, a naturally occurring stilbenoid. We demonstrate that nontoxic doses of resveratrol protect cells against a variety of stresses that are largely involved in age-related brain pathologies. These included oxidative, DNA damage, metal toxicity, heat, hypoxia, and protein aggregation stresses. Furthermore, it caused differentiation of cells to functional astrocytes and neurons as characterized by the upregulation of their specific protein markers. These findings endorse multiple bioactivities of resveratrol and encourage them to be tested for their benefits in animal models and humans.

Natural Polyphenols Targeting Senescence: A Novel Prevention and Therapy Strategy for Cancer

Cancer is one of the most serious diseases endangering human health. In view of the side effects caused by chemotherapy and radiotherapy, it is necessary to develop low-toxic anti-cancer compounds. Polyphenols are natural compounds with anti-cancer properties and their application is a considerable choice. Pro-senescence therapy is a recently proposed anti-cancer strategy and has been shown to effectively inhibit cancer. It is of great significance to clarify the mechanisms of polyphenols on tumor suppression by inducing senescence. In this review, we delineated the characteristics of senescent cells, and summarized the mechanisms of polyphenols targeting tumor microenvironment and inducing cancer cell senescence for cancer prevention and therapy. Although many studies have shown that polyphenols effectively inhibit cancer by targeting senescence, it warrants further investigation in preclinical and clinical studies.

LncRNA NEAT1 affects inflammatory response by targeting miR-129-5p and regulating Notch signaling pathway in epilepsy

It is crucial to understand the molecular mechanisms involved in epileptogenesis. This study aims to investigate the role of lncRNA NEAT1, miR-129-5p and Notch signaling pathway in epilepsy. In this research, temporal lobe tissues were collected from patients with epilepsy and healthy controls. The CTX-TNA cells were treated with IL-1β to establish as epilepsy cell model, which were then manipulated the expression level of NEAT1, miR-129-5p and Notch1 to investigate their roles in the epilepsy progression. The expression levels of RNA and protein in temporal lobe tissues and epilepsy cell model were determined by RT-qPCR, western blotting or ELISA, respectively. MTT assay was utilized to analyze the cell viability. Dual-luciferase reporter assay was used to explore the interaction relationship between lncRNA NEAT1, miR-129-5p and Notch1. Silencing NEAT1 significantly reduced the expression levels of IL-6, COX-2 and TNF-α in epilepsy cell model. The overexpression of NEAT1 suppressed the expression level of miR-129-5p. Inhibiting miR-129-5p significantly increased the expression of IL-6, COX-2, TNF-α and Notch1. Furthermore, the expression levels of IL-6, COX-2 and TNF-α were increased after overexpressing Notch1 in miR-129-5p mimics-treated cells. The expression levels of Notch1, JAG1, and HES1 were decreased after transfecting with sh-NEAT1. However, compared with sh-NEAT1 group, the expression levels of Notch1, JAG1, HES1, IL-6 and TNF-α were reversed by miR-129-5p inhibition or Notch1 overexpression. The present study verified that lncRNA NEAT1 affected inflammatory response of epilepsy by suppressing miR-129-5p and further regulating Notch signaling pathway in IL-1β-induced epilepsy cell model.Abbreviations: CNS: Central nervous system; lncRNAs: Long noncoding RNAs; NEAT1: Nuclear-enriched abundant transcript 1; miRNAs: MicroRNAs; ATCC: American Type Culture Collection; DMEM: Dulbecco's Modified Eagle Medium; FBS: Fetal bovine serum; ELISA: Enzyme-linked immunosorbent assay; RT-qPCR: Reverse transcription-quantitative polymerase chain reaction; SD: Standard deviation; ANOVA: Analysis of variance; LPS: Ligand lipopolysaccharide; GLO1: Glyoxalase I.

Combination of dihydroartemisinin and resveratrol effectively inhibits cancer cell migrationviaregulation of the DLC1/TCTP/Cdc42 pathway

Mechanism of DHA combined with RES in inhibition of cancer cell migration by DLC1/TCTP/Cdc42 signaling.

In Vitro Toxicity Assessment of Stilbene Extract for Its Potential Use as Antioxidant in the Wine Industry

The reduction of sulfur dioxide in wine is a consumer's demand, considering the allergic effects that may occur in people who are sensitive to it. Stilbenes are candidates of great interest for this purpose because of their antioxidant/antimicrobial activities and health properties, and also because they are naturally found in the grapevine. In the present study, the in vitro toxicity of an extract from grapevine shoots (with a stilbene richness of 45.4%) was assessed in two human cell lines. Significant damage was observed from 30 μg/mL after 24 h, and 40 µg/mL after 48 h of exposure. Similarly, the ultrastructural study revealed a significant impairment of cell growing. The extract was able to protect cells against an induced oxidative stress at all concentrations studied. In view of the promising results, a more exhaustive toxicological assessment of the extract is needed to confirm the safety of its further use as additive in wine.

Evolvement of nutraceutical onion plants engineered for resveratrol biosynthetic pathway

Genetically engineered onion expressing codon-optimized VvSTS1 gene accumulated stilbenes and extended life span in yeast and can serve as potential nutraceutical. Resveratrol (RV) is a natural polyphenolic compound found in certain plant species including grapes. RV is well known for its nutraceutical properties and to assuage several disease conditions. Onion is the second most consumed vegetable worldwide and contains large quantities of precursor molecules, malonyl-CoA and para-coumaroyl-CoA that are needed for RV biosynthesis. The present study reports the development of nutraceutical onion by engineering RV biosynthetic pathway. A codon-optimized grapevine synthetic stilbene synthase gene (VvSTS1) was synthesized using native grapevine sequence. Six-week-old healthy yellowish compact nodular calli were co-cultivated with Agrobacterium tumefaciens harbouring pCAMBIA1300-hpt II-CaMV35S-VvSTS1-nos. PCR analysis revealed the presence of VvSTS1 and hpt II genes in putative transgenics. Southern blot analysis confirmed the integration of VvSTS1 gene and independent nature of transformants. LC-ESI-HRMS analysis revealed the accumulation of variable quantities of RV (24.98-50.18 µg/g FW) and its glycosylated form polydatin (33.6-67.15 µg/g FW) in both leaves and bulbs, respectively, indicating the successful engineering of RV biosynthetic pathway into onion. The transgenic onion bulb extracts extended the life span in haploid yeast. The transgenic onion accumulating RV and polydatin, developed for the first of its kind, may serve as a potential nutraceutical resource.

Flavin Oxidase-Induced ROS Generation Modulates PKC Biphasic Effect of Resveratrol on Endothelial Cell Survival

Background: Dietary intake of natural antioxidants is thought to impart protection against oxidative-associated cardiovascular diseases. Despite many in vivo studies and clinical trials, this issue has not been conclusively resolved. Resveratrol (RES) is one of the most extensively studied dietary polyphenolic antioxidants. Paradoxically, we have previously demonstrated that high RES concentrations exert a pro-oxidant effect eventually elevating ROS levels leading to cell death. Here, we further elucidate the molecular determinants underpinning RES-induced oxidative cell death. Methods: Using human umbilical vein endothelial cells (HUVECs), the effect of increasing concentrations of RES on DNA synthesis and apoptosis was studied. In addition, mRNA and protein levels of cell survival or apoptosis genes, as well as protein kinase C (PKC) activity were determined. Results: While high concentrations of RES reduce PKC activity, inhibit DNA synthesis and induce apoptosis, low RES concentrations elicit an opposite effect. This biphasic concentration-dependent effect (BCDE) of RES on PKC activity is mirrored at the molecular level. Indeed, high RES concentrations upregulate the proapoptotic Bax, while downregulating the antiapoptotic Bcl-2, at both mRNA and protein levels. Similarly, high RES concentrations downregulate the cell cycle progression genes, c-myc, ornithine decarboxylase (ODC) and cyclin D1 protein levels, while low RES concentrations display an increasing trend. The BCDE of RES on PKC activity is abrogated by the ROS scavenger Tempol, indicating that this enzyme acts downstream of the RES-elicited ROS signaling. The RES-induced BCDE on HUVEC cell cycle machinery was also blunted by the flavin inhibitor diphenyleneiodonium (DPI), implicating flavin oxidase-generated ROS as the mechanistic link in the cellular response to different RES concentrations. Finally, PKC inhibition abrogates the BCDE elicited by RES on both cell cycle progression and pro-apoptotic gene expression in HUVECs, mechanistically implicating PKC in the cellular response to different RES concentrations. Conclusions: Our results provide new molecular insight into the impact of RES on endothelial function/dysfunction, further confirming that obtaining an optimal benefit of RES is concentration-dependent. Importantly, the BCDE of RES could explain why other studies failed to establish the cardio-protective effects mediated by natural antioxidants, thus providing a guide for future investigation looking at cardio-protection by natural antioxidants.

Avenanthramide A Induces Cellular Senescence via miR-129-3p/Pirh2/p53 Signaling Pathway To Suppress Colon Cancer Growth

Cellular senescence is the state of irreversible cell cycle arrest that provides a blockade during oncogenic transformation and tumor development. Avenanthramide A (AVN A) is an active ingredient exclusively extracted from oats, which possesses antioxidant, anti-inflammatory, and anticancer activities. However, the underlying mechanism(s) of AVN A in the prevention of cancer progression remains unclear. In the current study, we revealed that AVN A notably attenuated tumor formation in an azoxymethane/dextran sulfate sodium (AOM/DSS) mouse model. AVN A treatment triggered cellular senescence in human colon cancer cells, evidenced by enlarging cellular size, upregulating β-galactosidase activity, γ-H2AX positive staining, and G1 phase arrest. Moreover, AVN A treatment significantly increased the expression of miR-129-3p, which markedly repressed the E3 ubiquitin ligase Pirh2 and two other targets, IGF2BP3 and CDK6. The Pirh2 silencing by miR-129-3p led to a significant increase in protein levels of p53 and its downstream target p21, which subsequently induced cell senescence. Taken together, our data indicate that miR-129-3p/Pirh2/p53 is a critical signaling pathway in AVN A induced cellular senescence and AVN A could be a potential chemopreventive strategy for cancer treatment.

Anti-cancer effects of polyphenols via targeting p53 signaling pathway: updates and future directions

The anticancer effects of polyphenols are ascribed to several signaling pathways including the tumor suppressor gene tumor protein 53 (p53). Expression of endogenous p53 is silent in various types of cancers. A number of polyphenols from a wide variety of dietary sources could upregulate p53 expression in several cancer cell lines through distinct mechanisms of action. The aim of this review is to focus the significance of p53 signaling pathways and to provide molecular intuitions of dietary polyphenols in chemoprevention by monitoring p53 expression that have a prominent role in tumor suppression.

Resveratrol inhibits cancer cell proliferation by impairing oxidative phosphorylation and inducing oxidative stress

The resveratrol (RSV) efficacy to affect the proliferation of several cancer cell lines was initially examined. RSV showed higher potency to decrease growth of metastatic HeLa and MDA-MB-231 (IC₅₀ = 200-250 μM) cells than of low metastatic MCF-7, SiHa and A549 (IC₅₀ = 400-500 μM) and non-cancer HUVEC and 3T3 (IC₅₀≥600 μM) cells after 48 h exposure. In order to elucidate the biochemical mechanisms underlying RSV anti-cancer effects, the energy metabolic pathways and the oxidative stress metabolism were analyzed in HeLa cells as metastatic-type cell model. RSV (200 μM/48 h) significantly decreased both glycolysis and oxidative phosphorylation (OxPhos) protein contents (30-90%) and fluxes (40-70%) vs. non-treated cells. RSV (100 μM/1-5 min) also decreased at a greater extent OxPhos flux (net ADP-stimulated respiration) of isolated tumor mitochondria (> 50%) than of non-tumor mitochondria (< 50%), particularly with succinate as oxidizable substrate. In addition, RSV promoted an excessive cellular ROS (2-3 times) production corresponding with a significant decrement in the SOD activity (but not in its content) and GSH levels; whereas the catalase, glutahione reductase, glutathione peroxidase and glutathione-S-transferase activities (but not their contents) remained unchanged. RSV (200 μM/48 h) also induced cellular death although not by apoptosis but rather by promoting a strong mitophagy activation (65%). In conclusion, RSV impaired OxPhos by inducing mitophagy and ROS over-production, which in turn halted metastatic HeLa cancer cell growth.

Resveratrol Enhances Apoptotic and Oxidant Effects of Paclitaxel through TRPM2 Channel Activation in DBTRG Glioblastoma Cells

Numerous studies have reported a strong association between increased production of reactive oxygen species (ROS) and the pathobiology of several diseases, and cancer in particular. Therefore, manipulation of cellular oxidative stress levels represents an important therapeutic target. Recently, resveratrol (RESV), a naturally occurring phytochemical, has been shown to sensitize several cell lines to the anticancer effects of other chemotherapeutic agents, including paclitaxel (PAX). However, the molecular mechanisms of action of RESV through oxidative sensitive TRPM2 channel activation remain unclear. The aim of this study was to evaluate the effect of combination therapy of RESV and PAX on activation of TRPM2 in DBTRG glioblastoma cells. DBTRG cells were divided into four treatment groups: control, RESV (50 μM), PAX (50 μM), and PAX + RESV for 24 hours. Our data shows that markers for apoptosis, mitochondrial membrane depolarization and mitochondrial function, intracellular steady-state ROS levels, caspase 3 activity, TRPM2 current density, and Ca²⁺ florescence intensity were significantly increased in DBTRG cells following treatment with PAX and RESV, respectively, although cell viability was also decreased by these treatments. These biochemical markers were further increased to favor the anticancer effects of PAX in DBTRG cells in combination with RESV. The PAX and RESV-mediated increase in current density and Ca²⁺ florescence intensity was decreased with a TRPM2 blocker. This suggests that for this combination therapy to have a substantial effect on apoptosis and cell viability, the TRPM2 channel must be stimulated.

Resveratrol as a Tumor-Suppressive Nutraceutical Modulating Tumor Microenvironment and Malignant Behaviors of Cancer

Tumor-suppressive effects of resveratrol have been shown in various types of cancer. However, regulation of tumor microenvironment by resveratrol is still unclear. Recent findings suggest resveratrol can potentiate its tumor-suppressive effect through modulation of the signaling pathways of cellular components (fibroblasts, macrophages and T cells). Also, studies have shown that resveratrol can suppress malignant phenotypes of cancer cells acquired in response to stresses of the tumor microenvironment, such as hypoxia, oxidative stress and inflammation. We discuss the effects of resveratrol on cancer cells in stress environment of tumors as well as interactions between cancer cells and non-cancer cells in this review.

Increased expression of tripartite motif (TRIM) like 2 promotes tumoral growth in human oral cancer

Tripartite motif family-like 2 (TRIML2), a member of the TRIM proteins family, is closely related to Alzheimer's disease, however, no studies of TRIML2 have been published in the cancer research literature. In the current study, we investigated the expression level of TRIML2 and its molecular mechanisms in human oral squamous cell carcinoma (OSCC); reverse transcriptase-quantitative polymerase chain reaction, immunoblot analysis, and immunohistochemistry showed that TRIML2 is up-regulated significantly in OSCCs in vitro and in vivo. TRIML2 knockdown OSCC cells showed decreased cellular proliferation by cell-cycle arrest at G1 phase that resulted from down-regulation of CDK4, CDK6, and cyclin D1 and up-regulation of p21^Cip1 and p27^Kip1. Surprisingly, resveratrol, a polyphenol, led to not only down-regulation of TRIML2 but also cell-cycle arrest at G1 phase similar to TRIML2 knockdown experiments. Taken together, we concluded that TRIML2 might play a significant role in tumoral growth and that resveratrol may be a new drug for treating OSCC by interfering with TRIML2 function.