Resveratrol enhances p53 acetylation and apoptosis in prostate cancer by inhibiting MTA1/NuRD complex

Stilbenes: a promising small molecule modulator for epigenetic regulation in human diseases

Stilbenes are characterized by a vinyl group connecting two benzene rings to form the basic parent nucleus. Hydrogen atoms on different positions of the benzene rings can be substituted with hydroQxyl groups. These unique structural features confer anti-inflammatory, antibacterial, antiviral, antioxidant, anticancer, cardiovascular protective, and neuroprotective pharmacological effects upon these compounds. Numerous small molecule compounds have demonstrated these pharmacological activities in recent years, including Resveratrol, and Pterostilbene, etc. Tamoxifen and Raloxifene are FDA-approved commonly prescribed synthetic stilbene derivatives. The emphasis is on the potential of these small molecules and their structural derivatives as epigenetic regulators in various diseases. Stilbenes have been shown to modulate epigenetic marks, such as DNA methylation and histone modification, which can alter gene expression patterns and contribute to disease development. This review will discuss the mechanisms by which stilbenes regulate epigenetic marks in various diseases, as well as clinical trials, with a focus on the potential of small molecule and their derivatives such as Resveratrol, Pterostilbene, and Tamoxifen.

Molecular Efficacy of Gnetin C as Dual-Targeted Therapy for Castrate-Resistant Prostate Cancer

SCOPE

Resistance of castrate-resistant prostate cancer (CRPC) to enzalutamide (Enz) involves the expression of constitutively active androgen receptor splice variant (AR-V7). In addition to altered AR pathways, CRPC is characterized by "non-AR-driven" signaling, which includes an overexpression of metastasis-associated protein 1 (MTA1). Combining natural compounds with anticancer drugs may enhance drug effectiveness while reducing adverse effects. In this study, the in vitro and in vivo anticancer effects of Gnetin C (GnC) alone and in combination with Enz against CRPC are examined.

METHODS AND RESULTS

The effects of GnC alone and in combination with Enz are assessed by cell viability, clonogenic survival, cell migration, and AR and MTA1 expression using 22Rv1 cells. The tumor growth in vivo is assessed by bioluminescent imaging, western blots, RT-PCR, and IHC. GnC alone and in combined treatment inhibit cell viability, clonogenic survival and migration, and AR and MTA1 expression in 22Rv1 cells. The underlying AR- and MTA1-targeted anticancer mechanisms of treatments in vivo involve inhibition of proliferation and angiogenesis, and induction of apoptosis.

CONCLUSION

The findings demonstrate that GnC alone and GnC combined with Enz effectively inhibits AR- and MTA1-promoted tumor-progression in advanced CRPC, which indicates its potential as a novel therapeutic approach for CRPC.

Resveratrol induces apoptosis by modulating the reciprocal crosstalk between p53 and Sirt-1 in the CRC tumor microenvironment

Introduction

P53 represents a key player in apoptosis-induction in cancers including colorectal cancer (CRC) that ranks third worldwide in cancer prevalence as well as mortality statistics. Although a pro-apoptotic effect of resveratrol has been repeatedly proven in CRC cells, its pathway mechanisms are not completely understood, as there are controversial statements in the literature regarding its activation or inhibition of the counteracting proteins Sirt-1 and p53.

Methods

CRC cells as wild-type (HCT-116 WT) or p53-deficient (HCT-116 p53-/-) were cultured using multicellular tumor microenvironment (TME) cultures containing T-lymphocytes and fibroblasts to elucidate the role of p53/Sirt-1 modulation in resveratrol's concentration-dependent, pro-apoptotic, and thus anti-cancer effects.

Results

Resveratrol dose-dependently inhibited viability, proliferation, plasticity as well as migration, and induced apoptosis in HCT-116 WT more effectively than in HCT-116 p53-/- cells. Moreover, resveratrol stimulated Sirt-1 expression when administered at low concentrations (<5µM) but suppressed it when added at high concentrations (>10µM) to CRC-TME. In parallel, similar to the knockdown of Sirt-1 at the mRNA level, treatment with high-concentration resveratrol boosted the acetylation of p53, the expression of p21, Bax, cytochrome C, caspase-3, and ultimately induced apoptosis in CRC WT but not in CRC p53-/- cells. Notably, increasing concentrations of resveratrol were found to promote hyperacetylation of p53 and FOXO3a as post-translational substrates of Sirt-1, indicating a negative regulatory loop between Sirt-1 and p53.

Discussion

These results demonstrate for the first time, a negative reciprocal crosstalk between the regulatory circuits of p53 and Sirt-1, consequently, apoptosis induction by higher resveratrol concentrations in CRC-TME.

Metabolo-epigenetic interplay provides targeted nutritional interventions in chronic diseases and ageing

Epigenetic modifications are chemical modifications that affect gene expression without altering DNA sequences. In particular, epigenetic chemical modifications can occur on histone proteins -mainly acetylation, methylation-, and on DNA and RNA molecules -mainly methylation-. Additional mechanisms, such as RNA-mediated regulation of gene expression and determinants of the genomic architecture can also affect gene expression. Importantly, depending on the cellular context and environment, epigenetic processes can drive developmental programs as well as functional plasticity. However, misbalanced epigenetic regulation can result in disease, particularly in the context of metabolic diseases, cancer, and ageing. Non-communicable chronic diseases (NCCD) and ageing share common features including altered metabolism, systemic meta-inflammation, dysfunctional immune system responses, and oxidative stress, among others. In this scenario, unbalanced diets, such as high sugar and high saturated fatty acids consumption, together with sedentary habits, are risk factors implicated in the development of NCCD and premature ageing. The nutritional and metabolic status of individuals interact with epigenetics at different levels. Thus, it is crucial to understand how we can modulate epigenetic marks through both lifestyle habits and targeted clinical interventions -including fasting mimicking diets, nutraceuticals, and bioactive compounds- which will contribute to restore the metabolic homeostasis in NCCD. Here, we first describe key metabolites from cellular metabolic pathways used as substrates to "write" the epigenetic marks; and cofactors that modulate the activity of the epigenetic enzymes; then, we briefly show how metabolic and epigenetic imbalances may result in disease; and, finally, we show several examples of nutritional interventions - diet based interventions, bioactive compounds, and nutraceuticals- and exercise to counteract epigenetic alterations.

Polyphenols as Potent Epigenetics Agents for Cancer

Human diseases such as cancer can be caused by aberrant epigenetic regulation. Polyphenols play a major role in mammalian epigenome regulation through mechanisms and proteins that remodel chromatin. In fruits, seeds, and vegetables, as well as food supplements, polyphenols are found. Compounds such as these ones are powerful anticancer agents and antioxidants. Gallic acid, kaempferol, curcumin, quercetin, and resveratrol, among others, have potent anti-tumor effects by helping reverse epigenetic changes associated with oncogene activation and tumor suppressor gene inactivation. The role dietary polyphenols plays in restoring epigenetic alterations in cancer cells with a particular focus on DNA methylation and histone modifications was summarized. We also discussed how these natural compounds modulate gene expression at the epigenetic level and described their molecular targets in cancer. It highlights the potential of polyphenols as an alternative therapeutic approach in cancer since they modulate epigenetic activity.

Disease-associated regulation of gene expression by resveratrol: Special focus on the PI3K/AKT signaling pathway

Resveratrol (3,5,4′-trihydroxy-trans-stilbene) is a natural phenol that is present in the skin of the grape, blueberry, raspberry, mulberry, and peanut. This substance is synthesized in these plants following injury or exposure to pathogens. Resveratrol is used as a dietary supplement for a long time and its effects have been assessed in animal models of human disorders. It has potential beneficial effects in diverse pathological conditions such as diabetes mellitus, obesity, hypertension, neoplastic conditions, Alzheimer's disease, and cardiovascular disorders. Notably, resveratrol has been found to affect the expression of several genes including cytokine coding genes, caspases, matrix metalloproteinases, adhesion molecules, and growth factors. Moreover, it can modulate the activity of several signaling pathways such as PI3K/AKT, Wnt, NF-κB, and Notch pathways. In the current review, we summarize the results of studies that reported modulatory effects of resveratrol on the expression of genes and the activity of signaling pathways. We explain these results in two distinct sections of non-neoplastic and neoplastic conditions.

The Anticancer Potential of Plant-Derived Nutraceuticals via the Modulation of Gene Expression

Current studies show that approximately one-third of all cancer-related deaths are linked to diet and several cancer forms are preventable with balanced nutrition, due to dietary compounds being able to reverse epigenetic abnormalities. An appropriate diet in cancer patients can lead to changes in gene expression and enhance the efficacy of therapy. It has been demonstrated that nutraceuticals can act as powerful antioxidants at the cellular level as well as anticarcinogenic agents. This review is focused on the best studies on worldwide-available plant-derived nutraceuticals: curcumin, resveratrol, sulforaphane, indole-3-carbinol, quercetin, astaxanthin, epigallocatechin-3-gallate, and lycopene. These compounds have an enhanced effect on epigenetic changes such as histone modification via HDAC (histone deacetylase), HAT (histone acetyltransferase) inhibition, DNMT (DNA methyltransferase) inhibition, and non-coding RNA expression. All of these nutraceuticals are reported to positively modulate the epigenome, reducing cancer incidence. Furthermore, the current review addresses the issue of the low bioavailability of nutraceuticals and how to overcome the drawbacks related to their oral administration. Understanding the mechanisms by which nutraceuticals influence gene expression will allow their incorporation into an “epigenetic diet” that could be further capitalized on in the therapy of cancer.

Metabolite-derived protein modifications modulating oncogenic signaling

Malignant growth is defined by multiple aberrant cellular features, including metabolic rewiring, inactivation of tumor suppressors and the activation of oncogenes. Even though these features have been described as separate hallmarks, many studies have shown an extensive mutual regulatory relationship amongst them. On one hand, the change in expression or activity of tumor suppressors and oncogenes has extensive direct and indirect effects on cellular metabolism, activating metabolic pathways required for malignant growth. On the other hand, the tumor microenvironment and tumor intrinsic metabolic alterations result in changes in intracellular metabolite levels, which directly modulate the protein modification of oncogenes and tumor suppressors at both epigenetic and post-translational levels. In this mini-review, we summarize the crosstalk between tumor suppressors/oncogenes and metabolism-induced protein modifications at both levels and explore the impact of metabolic (micro)environments in shaping these.

Synergistic effects of natural products in combination with anticancer agents in prostate cancer: A scoping review

Background: Prostate cancer is the second most common cancer in men and has the fourth highest mortality among men worldwide. Different combination therapies for cancer are being tested, and among them, the integration of natural products is increasing. This study reviews research on the combination of anticancer drugs and natural products for the treatment of prostate cancer and suggests future directions in this field.

Methods: Articles were identified by searching the PubMed, Embase, and Cochrane Library databases. Search keywords included the following: “Antineoplastic agents,” “Anticancer drug,” “Phytotherapy,” “Natural product,” “Drug synergism,” and “Synergistic effect”. The selection process focused on whether the differences in efficacy of anticancer drugs were evaluated when combined with natural products.

Results: Nineteen studies were included. All 19 studies evaluated efficacy in vitro, as well as 10 in vivo. There were 13 studies on a single compound extracted from natural products, three studies on mushroom and herb extracts, and three studies on herbal medicines consisting of three herbs, and a dietary supplement containing 10 herbs. Cancer cell lines used were PC-3 in nine studies, LNCaP in six studies, C4-2 in five studies, DU-145 in four studies, and 22Rv1 in two studies. Anti-cancer drugs co-administered were as follows: docetaxel in nine studies, doxorubicin and enzalutamide in three studies, paclitaxel and suberoylanilide hydroxamic acid in two studies, and cisplatin, vincristine, and bicalutamide in one study each.

Conclusion: Although prostate cancer is prevalent worldwide, there are relatively few studies on the use of natural products with anticancer agents as treatment. Since it has reported that the efficacy of anticancer drugs is enhanced by coadministration of natural products, it is necessary to conduct further studies on this.

Dietary stilbenes as modulators of specific miRNAs in prostate cancer

Accumulated experimental data have suggested that natural plant products may be effective miRNA-modulating chemopreventive and therapeutic agents. Dietary polyphenols such as flavonoids, stilbenes, and lignans, among others, have been intensively studied for their miRNA-mediated cardioprotective, antioxidant, anti-inflammatory and anticancer properties. The aim of this review is to outline known stilbene-regulated miRNAs in cancer, with a special focus on the interplay between various miRNAs and MTA1 signaling in prostate cancer. MTA1 is an epigenetic reader and an oncogenic transcription factor that is overexpressed in advanced prostate cancer and metastasis. Not surprisingly, miRNAs that are linked to MTA1 affect cancer progression and the metastatic potential of cells. Studies led to the identification of MTA1-associated pro-oncogenic miRNAs, which are regulated by stilbenes such as resveratrol and pterostilbene. Specifically, it has been shown that inhibition of the activity of the MTA1 regulated oncogenic miR-17 family of miRNAs, miR-22, and miR-34a by stilbenes leads to inhibition of prostatic hyperplasia and tumor progression in mice and reduction of proliferation, survival and invasion of prostate cancer cells in vitro. Taken together, these findings implicate the use of resveratrol and its analogs as an attractive miRNA-mediated chemopreventive and therapeutic strategy in prostate cancer and the use of circulating miRNAs as potential predictive biomarkers for clinical development.

Chrysin Modulates Aberrant Epigenetic Variations and Hampers Migratory Behavior of Human Cervical (HeLa) Cells

Purpose: Plant-derived phytochemicals have shown epigenetic modulatory effect in different types of cancer by reversing the pattern of DNA methylation and chromatin modulation, thereby restoring the function of silenced tumor-suppressor genes. In the present study, attempts have been made to explore chrysin-mediated epigenetic alterations in HeLa cells. Methods: Colony formation and migration assays followed by methylation-specific PCR for examining the methylation status of CpG promoters of various tumor-suppressor genes (TSGs) and the expression of these TSGs at the transcript and protein levels were performed. Furthermore, global DNA methylation; biochemical activities of DNA methyltransferases (DNMTs), histone methyl transferases (HMTs), histone deacetylases (HDACs), and histone acetyl transferases (HATs) along with the expression analysis of chromatin-modifying enzymes; and H3 and H4 histone modification marks analyses were performed after chrysin treatment. Results: The experimental analyses revealed that chrysin treatment encourages cytostatic behavior as well as inhibits the migration capacity of HeLa cells in a time- and dose-dependent manner. Chrysin reduces the methylation of various tumor-suppressor genes, leading to their reactivation at mRNA and protein levels. The expression levels of various chromatin-modifying enzymes viz DNMTs, HMTs, HDACs, and HATS were found to be decreased, and H3 and H4 histone modification marks were modulated too. Also, reduced global DNA methylation was observed following the treatment of chrysin. Conclusion: This study concludes that chrysin can be used as a potential epigenetic modifier for cancer treatment and warrants for further experimental validation.

MTA1: A Vital Modulator in Prostate Cancer

Prostate cancer (PCa) is the most frequent cancer of the male genitourinary system and the second most common cancer in men worldwide. PCa has become one of the leading diseases endangering men's health in Asia in recent years, with a large increase in morbidity and mortality. MTA1 (metastasis-associated antigen-1), a transcriptional coregulator involved in histone deacetylation and nucleosome remodeling, is a member of the MTA family. MTA1 is involved in cell signaling, chromosomal remodeling, and transcriptional activities, all of which are important for epithelial cell progression, invasion, and growth. MTA1 has been demonstrated to play a significant role in the formation, progression, and metastasis of PCa, and MTA1 expression is specifically linked to PCa bone metastases. Therefore, MTA1 may be a potential target for PCa prevention and treatment. Here, we reviewed the structure, function, and expression of MTA1 in PCa as well as drugs that target MTA1 to highlight a potential new treatment for PCa.

Resveratrol-Based Nanoformulations as an Emerging Therapeutic Strategy for Cancer

Resveratrol is a polyphenolic stilbene derivative widely present in grapes and red wine. Broadly known for its antioxidant effects, numerous studies have also indicated that it exerts anti-inflammatory and antiaging abilities and a great potential in cancer therapy. Regrettably, the oral administration of resveratrol has pharmacokinetic and physicochemical limitations such as hampering its effects so that effective administration methods are demanding to ensure its efficiency. Thus, the present review explores the published data on the application of resveratrol nanoformulations in cancer therapy, with the use of different types of nanodelivery systems. Mechanisms of action with a potential use in cancer therapy, negative effects, and the influence of resveratrol nanoformulations in different types of cancer are also highlighted. Finally, the toxicological features of nanoresveratrol are also discussed.

Natural substances in cancer—do they work?

Owing to anticancer properties of selected natural substances, it is assumed that they have potential to be used in oncological therapy. Here, the recently proven effects of the selected natural polyphenols, resveratrol and curcumin, are described. Secondly, the potential of probiotics and prebiotics in modulation of immunological response and/or enhancing the chemotherapeutic treatments is reported based on the recent clinical trials. Further, the chapter presents current knowledge regarding the targeted supplementation of the patient with probiotic bacteria and known efficacy of probiotics to support immunotherapy. The major clinical trials are listed, aiming to verify whether, and to which extent the manipulation of patient’s microbiome can improve the outcome of chemotherapies. In the end, a potential of natural substances and feed ingredients to pose epigenetic changes is highlighted. The chapter provides an insight into the scientific proofs about natural bioactive substances in relation to cancer treatment, leaded by the question – do they really work?

Post-Translational Modifications That Drive Prostate Cancer Progression

While a protein primary structure is determined by genetic code, its specific functional form is mostly achieved in a dynamic interplay that includes actions of many enzymes involved in post-translational modifications. This versatile repertoire is widely used by cells to direct their response to external stimuli, regulate transcription and protein localization and to keep proteostasis. Herein, post-translational modifications with evident potency to drive prostate cancer are explored. A comprehensive list of proteome-wide and single protein post-translational modifications and their involvement in phenotypic outcomes is presented. Specifically, the data on phosphorylation, glycosylation, ubiquitination, SUMOylation, acetylation, and lipidation in prostate cancer and the enzymes involved are collected. This type of knowledge is especially valuable in cases when cancer cells do not differ in the expression or mutational status of a protein, but its differential activity is regulated on the level of post-translational modifications. Since their driving roles in prostate cancer, post-translational modifications are widely studied in attempts to advance prostate cancer treatment. Current strategies that exploit the potential of post-translational modifications in prostate cancer therapy are presented.

Nutrigenetics, nutrigenomics and phenotypic outcomes of dietary low-dose alcohol consumption in the suppression and induction of cancer development: evidence from in vitro studies

It is known that the intake of alcoholic beverages may impair genetic and epigenetic regulatory events with consequent crucial effects on cell phenotypes and that its association with selected genotypes can lead to a different risk of cancer in the population. The aim of this review is to pick up selected studies on this topic and recapitulate some of the biochemical and nutrigenetic/nutrigenomic aspects involved in the impact of dietary low-dose alcohol consumption on the switching-on or -off of tumorigenic pathways. These include i) the existence of predisposing or protective human genotypes and the relationship between dietary compounds and alcohol in the promotion or inhibition of carcinogenesis; ii) the effects of other components of alcoholic drinks in the modulation of the expression of oncogenes and oncosuppressors, the autophagic flux and the onset of apoptosis, with examples of their cytospecificity; and iii) the role of alcoholic beverage consumption within particular dietary regimens, including the Mediterranean diet. Taking all the data into account, several alcohol-associated bioactive dietary compounds appear capable to modulate peculiar intracellular pathways predisposing to or protecting from cancer. Advances in the nutrigenetic, nutrigenomic and nutriepigenetic knowledge complementing the biochemical and molecular approaches will help in unveiling their impact on health outcome.

Therapeutic Potential of Gnetin C in Prostate Cancer: A Pre-Clinical Study

Natural stilbenes have gained significant attention in the scientific community owing to their potential anticancer effects against prostate cancer. We recently reported that Gnetin C, a resveratrol (Res) dimer, demonstrated more potent inhibition of metastasis-associated protein 1/v-ets avian erythroblastosis virus E26 oncogene homolog 2 (MTA1/ETS2) axis in prostate cancer cell lines than other stilbenes. In this study, we investigated in vivo antitumor effects of Gnetin C in two doses (50 and 25 mg/kg, i.p.) using PC3M-Luc subcutaneous xenografts and compared these to Res and pterostilbene (Pter). We found that while vehicle-treated mice revealed rapid tumor progression, compounds-treated mice showed noticeable delay in tumor growth. Gnetin C in 50 mg/kg dose demonstrated the most potent tumor inhibitory effects. Gnetin C in 25 mg/kg dose exhibited tumor inhibitory effects comparable with Pter in 50 mg/kg dose. Consistent with the effective antitumor effects, Gnetin C-treated tumors showed reduced mitotic activity and angiogenesis and a significant increase in apoptosis compared to all the other groups. The data suggest that Gnetin C is more potent in slowing tumor progression in prostate cancer xenografts than Res or Pter. Taken together, we demonstrated, for the first time, that Gnetin C is a lead compound among stilbenes for effectively blocking prostate cancer progression in vivo.

MTA1, a Target of Resveratrol, Promotes Epithelial-Mesenchymal Transition of Endometriosis via ZEB2

Endometriosis is a benign disease that shares some malignant features. Epithelial-mesenchymal transition (EMT) is involved in the pathogenesis of endometriosis. Metastasis-associated protein 1 (MTA1) plays an important role in various cancers by promoting EMT, yet there are no studies on its function in endometriosis. In the present study, we found that MTA1 was highly expressed in the ectopic endometrium of endometriosis patients and that the expression of MTA1 was related to the revised American Fertility Society stage. MTA1 facilitated endometrial stroma cell proliferation, migration, and invasion by inducing EMT, and the promotion function and MTA1 expression were suppressed by resveratrol, a natural polyphenol. Moreover, we revealed that MTA1 induced EMT through interaction with ZEB2. The findings in a mouse endometriosis model further showed that MTA1 and ZEB2 were upregulated in ectopic tissues and that resveratrol inhibited the growth of ectopic lesions and expression of MTA1 and ZEB2. Taken together, we demonstrate that MTA1 is a protein that promotes EMT via interacting with ZEB2 in the pathogenesis of endometriosis, and may be a target of resveratrol.

Grape Powder Supplementation Attenuates Prostate Neoplasia Associated with Pten Haploinsufficiency in Mice Fed High-Fat Diet

SCOPE

Previous studies have identified potent anticancer activities of polyphenols in preventing prostate cancer. The aim of the current study is to evaluate the chemopreventive potential of grape powder (GP) supplemented diets in genetically predisposed and obesity-provoked prostate cancer.

METHODS AND RESULTS

Prostate-specific Pten heterozygous (Pten+/f ) transgenic mice are fed low- and high-fat diet (LFD and HFD, respectively) supplemented with 10% GP for 33 weeks, ad libitum. Prostate tissues are characterized using immunohistochemistry and western blots, and sera are analyzed by ELISA and qRT-PCR. Pten+/f mice fed LFD and HFD supplemented with 10% GP show favorable histopathology, significant reduction of the proliferative rate of prostate epithelial cells (Ki67), and rescue of PTEN expression. The most potent protective effect of GP supplementation is detected against HFD-induced increase in inflammation (IL-1β; TGF-β1), activation of cell survival pathways (Akt, AR), and angiogenesis (CD31) in Pten+/f mice. Moreover, GP supplementation reduces circulating levels of oncogenic microRNAs (miR-34a; miR-22) in Pten+/f mice. There are no significant changes in body weight and food intake in GP supplemented diet groups.

CONCLUSIONS

GP diet supplementation can be a beneficial chemopreventive strategy for obesity-related inflammation and prostate cancer progression. Monitoring serum miRNAs can facilitate the non-invasive evaluation of chemoprevention efficacy.

CANCER EPIGENETICS AND THE ROLE OF DIETARY ELEMENTS

Cancer has been a fatal disease since many decades. Over the time, it is presented in multiple ways and is a matter of consideration as accounts for the high rate of mortality. The aim of the current review was to focus on the genetics, epigenetics factors and role of medicinal plants for the cure of this inimical disease. Related articles available in English language (2002-2018) were reviewed with help of different database, including PubMed, Springer Link, Medline, Google Scholar and ScienceDirect. In order to ensure credibility and accuracy of data only those articles were considered which are published in indexed journals i.e. Web of Science and Scopus. This project was conducted at the Department of Pharmacy, Government College University, Faisalabad, Pakistan from 02-01-2019 to 28-02-2019. The genetic machinery is vibrantly involved in the interpretation of the signals and is observed to be affected by various dietary factors. A sequence of modified activities is observed with use of these dietary elements. However, the modification is reviewed through the histone acetyltransferase (HAT), histone deacetylase (HDAC) and DNA methyl transferase (DNMTs), effecting the expression of gene. These modified genes, in turn then express the signals in multiple reformed ways. Different dietary elements that are used such as polyphenol, alkaloid and flavonoids are effective against cancer. The progression of disease involves genetics and epigenetics due to amplification, translocation and mutation during gene expression. Though, many studies have been conducted elaborating the role of plants and their ingredients which play a part in inhibition of cancerous cells by blockade of cell cycle and apoptosis; more in-depth investigations are still required to identify the new drug target and novel therapeutic modalities.

Natural Compounds in Prostate Cancer Prevention and Treatment: Mechanisms of Action and Molecular Targets

Prostate cancer (PCa) represents a major cause of cancer mortality among men in developed countries. Patients with recurrent disease initially respond to androgen-deprivation therapy, but the tumor eventually progresses into castration-resistant PCa; in this condition, tumor cells acquire the ability to escape cell death and develop resistance to current therapies. Thus, new therapeutic approaches for PCa management are urgently needed. In this setting, natural products have been extensively studied for their anti-PCa activities, such as tumor growth suppression, cell death induction, and inhibition of metastasis and angiogenesis. Additionally, numerous studies have shown that phytochemicals can specifically target the androgen receptor (AR) signaling, as well as the PCa stem cells (PCSCs). Interestingly, many clinical trials have been conducted to test the efficacy of nutraceuticals in human subjects, and they have partially confirmed the promising results obtained in vitro and in preclinical models. This article summarizes the anti-cancer mechanisms and therapeutic potentials of different natural compounds in the context of PCa prevention and treatment.

Resveratrol targets PD-L1 glycosylation and dimerization to enhance antitumor T-cell immunity

New strategies to block the immune evasion activity of programmed death ligand-1 (PD-L1) are urgently needed. When exploring the PD-L1-targeted effects of mechanistically diverse metabolism-targeting drugs, exposure to the dietary polyphenol resveratrol (RSV) revealed its differential capacity to generate a distinct PD-L1 electrophoretic migration pattern. Using biochemical assays, computer-aided docking/molecular dynamics simulations, and fluorescence microscopy, we found that RSV can operate as a direct inhibitor of glyco-PD-L1-processing enzymes (α-glucosidase/α-mannosidase) that modulate N-linked glycan decoration of PD-L1, thereby promoting the endoplasmic reticulum retention of a mannose-rich, abnormally glycosylated form of PD-L1. RSV was also predicted to interact with the inner surface of PD-L1 involved in the interaction with PD-1, almost perfectly occupying the target space of the small compound BMS-202 that binds to and induces dimerization of PD-L1. The ability of RSV to directly target PD-L1 interferes with its stability and trafficking, ultimately impeding its targeting to the cancer cell plasma membrane. Impedance-based real-time cell analysis (xCELLigence) showed that cytotoxic T-lymphocyte activity was notably exacerbated when cancer cells were previously exposed to RSV. This unforeseen immunomodulating mechanism of RSV might illuminate new approaches to restore T-cell function by targeting the PD-1/PD-L1 immunologic checkpoint with natural polyphenols.

Epigenetic Gene Regulation by Dietary Compounds in Cancer Prevention

Traditionally, cancer has been viewed as a set of diseases that are driven by the accumulation of genetic mutations, but we now understand that disruptions in epigenetic regulatory mechanisms are prevalent in cancer as well. Unlike genetic mutations, however, epigenetic alterations are reversible, making them desirable therapeutic targets. The potential for diet, and bioactive dietary components, to target epigenetic pathways in cancer is now widely appreciated, but our understanding of how to utilize these compounds for effective chemopreventive strategies in humans is in its infancy. This review provides a brief overview of epigenetic regulation and the clinical applications of epigenetics in cancer. It then describes the capacity for dietary components to contribute to epigenetic regulation, with a focus on the efficacy of dietary epigenetic regulators as secondary cancer prevention strategies in humans. Lastly, it discusses the necessary precautions and challenges that will need to be overcome before the chemopreventive power of dietary-based intervention strategies can be fully harnessed.

Targeting HDAC Complexes in Asthma and COPD

Around three million patients die due to airway inflammatory diseases each year. The most notable of these diseases are asthma and chronic obstructive pulmonary disease (COPD). Therefore, new therapies are urgently needed. Promising targets are histone deacetylases (HDACs), since they regulate posttranslational protein acetylation. Over a thousand proteins are reversibly acetylated, and acetylation critically influences aberrant intracellular signaling pathways in asthma and COPD. The diverse set of selective and non-selective HDAC inhibitors used in pre-clinical models of airway inflammation show promising results, but several challenges still need to be overcome. One such challenge is the design of HDAC inhibitors with unique selectivity profiles, such as selectivity towards specific HDAC complexes. Novel strategies to disrupt HDAC complexes should be developed to validate HDACs further as targets for new anti-inflammatory pulmonary treatments.

MTA1-Dependent Anticancer Activity of Gnetin C in Prostate Cancer

The overexpression of metastasis-associated protein 1 (MTA1) in prostate cancer (PCa) contributes to tumor aggressiveness and metastasis. We have reported the inhibition of MTA1 by resveratrol and its potent analog pterostilbene in vitro and in vivo. We have demonstrated that pterostilbene treatment blocks the progression of prostatic intraepithelial neoplasia and adenocarcinoma in mouse models by inhibiting MTA1 expression and signaling. In the current study, we investigated the MTA1 targeted anticancer effects of Gnetin C, a resveratrol dimer, in comparison with resveratrol and pterostilbene. Using DU145 and PC3M PCa cells, we found that Gnetin C downregulates MTA1 more potently than resveratrol and pterostilbene. Further, Gnetin C demonstrated significant MTA1-mediated inhibitory effect on cell viability, colony formation, and migration, while showing a more potent induction of cell death than resveratrol or pterostilbene. In addition, we identified Gnetin C-induced substantial ETS2 (erythroblastosis E26 transformation-specific 2) downregulation, which is not only MTA1-dependent, but is also independent of MTA1 as a possible mechanism for the superior anticancer efficacy of Gnetin C in PCa. Together, these findings underscore the importance of novel potent resveratrol dimer, Gnetin C, as a clinically promising agent for the future development of chemopreventive and possibly combinatorial therapeutic approaches in PCa.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Knockdown of spliceosome U2AF1 significantly inhibits the development of human erythroid cells

U2AF1 (U2AF35) is the small subunit of the U2 auxiliary factor (U2AF) that constitutes the U2 snRNP (small nuclear ribonucleoproteins) of the spliceosome. Here, we examined the function of U2AF1 in human erythropoiesis. First, we examined the expression of U2AF1 during in vitro human erythropoiesis and showed that U2AF1 was highly expressed in the erythroid progenitor burst-forming-unit erythroid (BFU-E) cell stage. A colony assay revealed that U2AF1 knockdown cells failed to form BFU-E and colony-forming-unit erythroid (CFU-E) colonies. Our results further showed that knockdown of U2AF1 significantly inhibited cell growth and induced apoptosis in erythropoiesis. Additionally, knockdown of U2AF1 also delayed terminal erythroid differentiation. To explore the molecular basis of the impaired function of erythroid development, RNA-seq was performed and the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis results showed that several biological pathways, including the p53 signalling pathway, MAPK signalling pathway and haematopoietic cell lineage, were involved, with the p53 signalling pathway showing the greatest involvement. Western blot analysis revealed an increase in the protein levels of downstream targets of p53 following U2AF1 knockdown. The data further showed that depletion of U2AF1 altered alternatively spliced apoptosis-associated gene transcripts in CFU-E cells. Our findings elucidate the role of U2AF1 in human erythropoiesis and reveal the underlying mechanisms.

Targeting Cancer Via Resveratrol-Loaded Nanoparticles Administration: Focusing on In Vivo Evidence

Resveratrol (RSV) is a polyphenol endowed with potential therapeutic effects in chronic diseases, particularly in cancer, the second leading cause of death worldwide in the twenty-first century. The advent of nanotechnology application in the field of drug delivery allows to overcome the constrains associated with the conventional anticancer treatments, in particular chemotherapy, reducing its adverse side effects, off target risks and surpassing cancer multidrug chemoresistance. Moreover, the use of nanotechnology-based carriers in the delivery of plant-derived anticancer agents, such as RSV, has already demonstrated to surpass the poor water solubility, instability and reduced bioavailability associated with phytochemicals, improving their therapeutic activity, thus prompting pharmaceutical developments. This review highlights the in vivo anticancer potential of RSV achieved by nanotherapeutic approaches. First, RSV physicochemical, stability and pharmacokinetic features are described. Thereupon, the chemotherapeutic and chemopreventive properties of RSV are underlined, emphasizing the RSV numerous cancer molecular targets. Lastly, a comprehensive analysis of the RSV-loaded nanoparticles (RSV-NPs) developed and administered in different in vivo cancer models to date is presented. Nanoparticles (NPs) have shown to improve RSV solubility, stability, pharmacokinetics and biodistribution in cancer tissues, enhancing markedly its in vivo anticancer activity. RSV-NPs are, thus, considered a potential nanomedicine-based strategy to fight cancer; however, further studies are still necessary to allow RSV-NP clinical translation.

Traditional Chinese medicine as a cancer treatment: Modern perspectives of ancient but advanced science

Traditional Chinese medicine (TCM) has been practiced for thousands of years and at the present time is widely accepted as an alternative treatment for cancer. In this review, we sought to summarize the molecular and cellular mechanisms underlying the chemopreventive and therapeutic activity of TCM, especially that of the Chinese herbal medicine-derived phytochemicals curcumin, resveratrol, and berberine. Numerous genes have been reported to be involved when using TCM treatments and so we have selectively highlighted the role of a number of oncogene and tumor suppressor genes in TCM therapy. In addition, the impact of TCM treatment on DNA methylation, histone modification, and the regulation of noncoding RNAs is discussed. Furthermore, we have highlighted studies of TCM therapy that modulate the tumor microenvironment and eliminate cancer stem cells. The information compiled in this review will serve as a solid foundation to formulate hypotheses for future studies on TCM-based cancer therapy.

Dietary Compounds as Epigenetic Modulating Agents in Cancer

Epigenetic mechanisms control gene expression during normal development and their aberrant regulation may lead to human diseases including cancer. Natural phytochemicals can largely modulate mammalian epigenome through regulation of mechanisms and proteins responsible for chromatin remodeling. Phytochemicals are mainly contained in fruits, seeds, and vegetables as well as in foods supplements. These compounds act as powerful cellular antioxidants and anti-carcinogens agents. Several dietary compounds such as catechins, curcumin, genistein, quercetin and resveratrol, among others, exhibit potent anti-tumor activities through the reversion of epigenetic alterations associated to oncogenes activation and inactivation of tumor suppressor genes. In this review, we summarized the actual knowledge about the role of dietary phytochemicals in the restoration of aberrant epigenetic alterations found in cancer cells with a particular focus on DNA methylation and histone modifications. Furthermore, we discussed the mechanisms by which these natural compounds modulate gene expression at epigenetic level and described their molecular targets in diverse types of cancer. Modulation of epigenetic activities by phytochemicals will allow the discovery of novel biomarkers for cancer prevention, and highlights its potential as an alternative therapeutic approach in cancer.

Differential Methylation and Acetylation as the Epigenetic Basis of Resveratrol's Anticancer Activity

Numerous studies support the potent anticancer activity of resveratrol and its regulation of key oncogenic signaling pathways. Additionally, the activation of sirtuin 1, a deacetylase, by resveratrol has been known for many years, making resveratrol perhaps one of the earliest nutraceuticals with associated epigenetic activity. Such epigenetic regulation by resveratrol, and the mechanism thereof, has attracted much attention in the past decade. Focusing on methylation and acetylation, the two classical epigenetic regulations, we showcase the potential of resveratrol as an effective anticancer agent by virtue of its ability to induce differential epigenetic changes. We discuss the de-repression of tumor suppressors such as BRCA-1, nuclear factor erythroid 2-related factor 2 (NRF2) and Ras Associated Domain family-1α (RASSF-1α) by methylation, PAX1 by acetylation and the phosphatase and tensin homologue (PTEN) by both methylation and acetylation, in addition to the epigenetic regulation of oncogenic NF-κB and STAT3 signaling by resveratrol. Further, we evaluate the literature supporting the potentiation of HDAC inhibitors and the inhibition of DNMTs by resveratrol in different human cancers. This discussion underlines a robust epigenetic activity of resveratrol that warrants further evaluation, particularly in clinical settings.

Resveratrol induces p53 in colorectal cancer through SET7/9

Resveratrol is one of the most promising phytoalexins for use as an anti-cancer agent, which is present in the skin of red grapes and berries. Resveratrol has been demonstrated to modulate a number of signalling pathways that are involved in carcinogenesis. In the present study, the function of resveratrol as a pro-apoptotic agent in colorectal cancer cell lines, including HCT116, CO115 and SW48, was investigated. The results revealed that resveratrol supressed cell viability. Additionally, resveratrol enhanced the expression of tumour protein p53 (p53) and p53 target genes, including Bcl2 associated X, apoptosis regulator and Bcl2 binding component 3 that have a pivotal role in p53-dependent apoptosis. Furthermore, treating cells with resveratrol upregulated SET domain containing lysine methyltransferase 7/9 (SET7/9) expression, which positively regulates p53 through its mono-methylation at lysine 372, compared with untreated cells. Furthermore, treating cells with resveratrol induced the expression of apoptotic markers including cleaved caspase-3 and poly (ADP-ribose) polymerases (PARP) compared with untreated cells. However, the genetic knockdown of SET7/9 by short hairpin RNA attenuated the resveratrol-driven overexpression of p53, cleaved caspase-3 and PARP. Collectively, these results reveal the molecular mechanisms by which resveratrol induces p53 stability in colon cancer that results in the activation of p53-mediated apoptosis.

In Vitro Anticancer Properties of Table Grape Powder Extract (GPE) in Prostate Cancer

Although the link between diet and cancer is complex, epidemiological data confirm that diet is a risk factor for prostate cancer and indicate a reduced prostate cancer incidence associated with a diet rich in vegetables and fruits. Because of the known protective effect of grape seed extract (GSE) against prostate cancer, we evaluated the effects of grape powder extract (GPE) on cell viability, proliferation, and metastatic capability. Importantly, we explored the possible novel mechanism of GPE through metastasis-associated protein 1 (MTA1) downregulation in prostate cancer, since our previous studies indicated resveratrol (Res)- and pterostilbene (Pter)-induced MTA1-mediated anticancer activities in prostate cancer. We found that GPE inhibited the cell viability and growth of prostate cancer cells only at high 100 μg/mL concentrations. However, at low 1.5⁻15 μg/mL concentrations, GPE significantly reduced the colony formation and wound healing capabilities of both DU145 and PC3M cells. Moreover, we found that GPE inhibited MTA1 in a dose-dependent manner in these cells, albeit with considerably less potency than Res and Pter. These results indicate that stilbenes such as Res and Pter specifically and potently inhibit MTA1 and MTA1-associated proteins compared to GPE, which contains low concentrations of Res and mainly consists of other flavonoids and anthocyanidins. Our findings support continued interest in GPE as a chemopreventive and anti-cancer agent against prostate cancer but also emphasize the unique and specific properties of stilbenes on MTA1-mediated anticancer effects on prostate cancer.

Polypharmacology or Promiscuity? Structural Interactions of Resveratrol With Its Bandwagon of Targets

Resveratrol (3, 4', 5-trihydroxy-trans-stilbene) is a natural phytoalexin found in grapes and has long been thought to be the answer to the "French Paradox." There is no shortage of preclinical and clinical studies investigating the broad therapeutic activity of resveratrol. However, in spite of many comprehensive reviews published on the bioactivity of resveratrol, there has yet to be a report focused on the variety and complexity of its structural binding properties, and its multi-targeted role. An improved understanding of disease mechanisms at the systems level has enabled targeted polypharmacology to mature into a rational drug discovery approach. Unlike traditional hit-to-lead campaigns that typically optimize activity and selectivity for a single target, polypharmacological drugs aim to selectively target multiple proteins, while avoiding critical off target interactions. This strategy bears promise of improved efficacy and reduced clinical attrition. This review seeks to investigate whether the bioactivity of resveratrol is due to a polypharmacological effect or promiscuity of the phenolic small molecule by examining the modes of binding with its diverse collection of protein targets. We focused on annotated targets, identified via the ChEMBL database, and matched these targets to a representative structure deposited in the Protein Data Bank (PDB), as crystal structures are most informative in understanding modes of binding at the atomic level. We discuss the structural aspects of resveratrol itself that permits binding to multiple proteins in various signaling pathways. Furthermore, we suggest that resveratrol's bioactivity is a result of scaffold promiscuity rather than polypharmacology, and the variety of binding modes across targets display little similarity in the pattern of target interaction.

Transcriptome Sequencing Reveals the Differentially Expressed lncRNAs and mRNAs Involved in Cryoinjuries in Frozen-Thawed Giant Panda (Ailuropoda melanoleuca) Sperm

Sperm cryopreservation and artificial insemination are important methods for giant panda breeding and preservation of extant genetic diversity. Lower conception rates limit the use of artificial insemination with frozen-thawed giant panda sperm, due to the lack of understanding of the cryodamaging or cryoinjuring mechanisms in cryopreservation. Long non-coding RNAs (lncRNAs) are involved in regulating spermatogenesis. However, their roles during cryopreservation remain largely unexplored. Therefore, this study aimed to identify differentially expressed lncRNAs and mRNAs associated with cryodamage or freeze tolerance in frozen-thawed sperm through high throughput sequencing. A total of 61.05 Gb clean reads and 22,774 lncRNA transcripts were obtained. From the sequencing results, 1477 significantly up-regulated and 1,396 significantly down-regulated lncRNA transcripts from fresh and frozen-thawed sperm of giant panda were identified. GO and KEGG showed that the significantly dysregulated lncRNAs and mRNAs were mainly involved in regulating responses to cold stress and apoptosis, such as the integral component of membrane, calcium transport, and various signaling pathways including PI3K-Akt, p53 and cAMP. Our work is the first systematic profiling of lncRNA and mRNA in fresh and frozen-thawed giant panda sperm, and provides valuableinsights into the potential mechanism of cryodamage in sperm.

MTA1 drives malignant progression and bone metastasis in prostate cancer

Prostate cancer often metastasizes to the bone, leading to morbidity and mortality. While metastasis-associated protein 1 (MTA1) is highly overexpressed in metastatic tumors and bone metastatic lesions, its exact role in the development of metastasis is unknown. Here, we report the role of MTA1 in prostate cancer progression and bone metastasis in vitro and in vivo. We found that MTA1 silencing diminished formation of bone metastases and impaired tumor growth in intracardiac and subcutaneous prostate cancer xenografts, respectively. This was attributed to reduced colony formation, invasion, and migration capabilities of MTA1 knockdown cells. Mechanistic studies revealed that MTA1 silencing led to a significant decrease in the expression of cathepsin B (CTSB), a cysteine protease critical for bone metastasis, with an expected increase in the levels of E-cadherin in both cells and xenograft tumors. Moreover, meta-analysis of clinical samples indicated a positive correlation between MTA1 and CTSB. Together, these results demonstrate the critical role of MTA1 as an upstream regulator of CTSB-mediated events associated with cell invasiveness and raise the possibility that targeting MTA1/CTSB signaling in the tumor may prevent the development of bone metastasis in prostate cancer.

Z-ligustilide restores tamoxifen sensitivity of ERa negative breast cancer cells by reversing MTA1/IFI16/HDACs complex mediated epigenetic repression of ERa

Emerging evidence indicates epigenetic modification represses estrogen receptor α (ERα) and contributes to the resistance to tamoxifen in aggressive ERα-negative (ERα⁻) breast cancer. Z-ligustilide is a major compound in Radix Angelica sinensis, an herb from traditional Chinese medicine (TCM) most frequently prescribed for breast cancer. However, the role of Z-ligustilide in ERα⁻ breast cancer and epigenetic modification remains largely unknown. Herein we showed, for the first time, that Z-ligustilide restored the growth inhibition of tamoxifen on ERα⁻ breast cancer cells. Apoptosis and S and G2/M phases cell cycle arrest were induced by combinatorial Z-ligustilide and tamoxifen. Importantly, Z-ligustilide reactivated the ERα expression and transcriptional activity, which is proved to be indispensable for restoring the sensitivity to tamoxifen. Interestingly, Z-ligustilide increased Ace-H3 (lys9/14) enrichment in the ERα promoter. Moreover, Z-ligustilide dramatically reduced the enrichment of metastasis-associated protein 1 (MTA1) as well as IFN-γ-inducible protein 16 (IFI16) and histone deacetylases (HDACs) onto the ERα promoter. Meanwhile, Z-ligustilide downregulated MTA1, IFI16 and HDACs, which caused destabilization of the corepressor complex. Collectively, our study not only highlights Z-ligustilide as a novel epigenetic modulator, but also opens new possibilities from TCM for treating aggressive tamoxifen-resistant breast cancer.

Resveratrol changes spermatogonial stem cells (SSCs) activity and ameliorates their loss in busulfan-induced infertile mouse

The decline of quantity and quality of sperm are correlated with the increasing age and some anti-cancer compounds such as busulfan. Previous studies have shown that Resveratrol (Res) inhibits tumorigenesis and metastasis of many cancers including mammary tumor, prostate and pancreatic cancers. It acts as anti-age in mouse and human, however, little is known about its protective effect on aged spermatogonial stem cells (SSCs). Here, we investigated the effects of Res in vitro on SSCs using C18-4 cells and in vivo in busulfan-induced azoospermia mice model. The results showed that Res at different concentrations had different effects on C18-4 cells. Treatment with 2 μM of Res promotes cell proliferation and inhibits apoptosis, but stimulates apoptosis with a higher concentration (20 μM) in C18-4 cells. Using busulfan-induced infertility mice model, we demonstrated that Res (30 mg/kg/d and 100 mg/kg/d) clearly ameliorated SSC loss to recover the spermatogenesis. Taken together, our data suggest that Res might be an approach for therapeutic intervention to promote SSC proliferation and cease SSC loss in azoospermia mice model induced by busulfan.

Epigenetic Regulatory Mechanisms Induced by Resveratrol

Resveratrol (RVT) is one of the main natural compounds studied worldwide due to its potential therapeutic use in the treatment of many diseases, including cancer, diabetes, cardiovascular diseases, neurodegenerative diseases and metabolic disorders. Nevertheless, the mechanism of action of RVT in all of these conditions is not completely understood, as it can modify not only biochemical pathways but also epigenetic mechanisms. In this paper, we analyze the biological activities exhibited by RVT with a focus on the epigenetic mechanisms, especially those related to DNA methyltransferase (DNMT), histone deacetylase (HDAC) and lysine-specific demethylase-1 (LSD1).

Targeting MTA1/HIF-1α signaling by pterostilbene in combination with histone deacetylase inhibitor attenuates prostate cancer progression

The metastasis‐associated protein 1(MTA1)/histone deacetylase (HDAC) unit is a cancer progression‐related epigenetic regulator, which is overexpressed in hormone‐refractory and metastatic prostate cancer (PCa). In our previous studies, we found a significantly increased MTA1 expression in a prostate‐specific Pten‐null mouse model. We also demonstrated that stilbenes, namely resveratrol and pterostilbene (Pter), affect MTA1/HDAC signaling, including deacetylation of tumor suppressors p53 and PTEN. In this study, we examined whether inhibition of MTA1/HDAC using combination of Pter and a clinically approved HDAC inhibitor, SAHA (suberoylanilide hydroxamic acid, vorinostat), which also downregulates MTA1, could block prostate tumor progression in vivo. We generated and utilized a luciferase reporter in a prostate‐specific Pten‐null mouse model (Pb‐Cre⁺; Pten^f/f; Rosa26^Luc/+) to evaluate the anticancer efficacy of Pter/SAHA combinatorial approach. Our data showed that Pter sensitized tumor cells to SAHA treatment resulting in inhibiting tumor growth and additional decline of tumor progression. These effects were dependent on the reduction of MTA1‐associated proangiogenic factors HIF‐1α, VEGF, and IL‐1β leading to decreased angiogenesis. In addition, treatment of PCa cell lines in vitro with combined Pter and low dose SAHA resulted in more potent inhibition of MTA1/HIF‐1α than by high dose SAHA alone. Our study provides preclinical evidence that Pter/SAHA combination treatment inhibits MTA1/HIF‐1α tumor‐promoting signaling in PCa. The beneficial outcome of combinatorial strategy using a natural agent and an approved drug for higher efficacy and less toxicity supports further development of MTA1‐targeted therapies in PCa.

Tumoricidal activities of pterostilbene depend upon destabilizing the MTA1-NuRD complex and enhancing P53 acetylation in hepatocellular carcinoma

The present study aimed to assess the tumoricidal effect of metastasis-associated protein 1 (MTA1) induced by pterostilbene (PTER) in hepatocellular carcinoma (HCC). The SMMC-7721 hepatoma cell line was treated with PTER. Following treatment, the mRNA transcript abundance of MTA1 was measured using quantitative polymerase chain reaction. Additionally, cell viability was determined using an MTT assay, and protein expression was measured through western blotting. Cell invasion, motility and apoptosis, as well as the cell cycle, were also investigated. Following PTER treatment, MTA1, histone deacetylase (HDAC) 1 and HDAC2 were downregulated, whereas the ratio of acetyl-p53 to total p53 was increased in HCC cells. Cell viability decreased as the PTER dose increased. MTA1 may be associated with proliferation, motility, invasion and metastasis in HCC cells. PTER appeared to repress cell proliferation, trigger apoptosis, induce cell cycle arrest, and inhibit motility and invasion via MTA1 in human liver cancer cells. The results of the present study demonstrated that PTER can downregulate the MTA1-nucleosome remodeling and deacetylase complex, and enhance p53 acetylation to inhibit the growth of tumor cells in HCC.

A comparative assessment of antiproliferative properties of resveratrol and ethanol leaf extract of Anogeissus leiocarpus (DC) Guill and Perr against HepG2 hepatocarcinoma cells

Background

Epidemiological and experimental evidences have shown cancer as a leading cause of death worldwide. Although the folklore use of plants as a reliable source of health-restoring principles is well-documented, the search for more of such plants that are active against diseases, such as cancer, continues. We report here a laboratory-based evidence of the relevance of an ethanol leaf extract of Anogeissus leiocarpus (A2L) in comparison with resveratrol, a natural polyphenol, in cancer therapy.

Methods

The quantitative assessment of flavonoid and phenolic contents involved quercetin and gallic acid as standards, respectively were determined using spectrophotometry. Cytotoxicity was determined fluorometrically using propidium-iodide-staining method. Antioxidant status, adenosine triphosphate (ATP) levels, caspase activities and mitochondrial integrity were assessed using fluorometry/luminometry.

Results

The antioxidant assay demonstrated that A2L possesses a strong antioxidant capacity as compared with the reference compounds, ascorbic acid and butylated hydroxytoluene. This is further buttressed by the significantly high level of phenolics obtained in the quantitative assessment of the extract. A 72-h post-treatment examination indicated that both A2L and resveratrol modulate the proliferation of HepG2 liver carcinoma cells in a time- and concentration-dependent manner. Determination of the total nuclei area, propidium-iodide negative and positive nuclei areas all further buttress the modulation of cell proliferation by A2L and resveratrol with the indication that the observed cell death is due to apoptosis and necrosis at lower and higher concentrations of treatments respectively. At lower concentrations (0.39–3.13 μg/mL), resveratrol possesses higher tendencies to activate caspases 3 and 7. Bioenergetically, both resveratrol and A2L do not adversely affect the cells at lower concentrations (0.39–6.25 μg/mL for resveratrol and 12.5–100.0 μg/mL for A2L) except at higher concentrations (12.5–25.0 μg/mL for resveratrol and 200–800 μg/mL for A2L) which are more pronounced in A2L-treated cells. Furthermore, the antioxidant status of HepG2 cells is not perturbed by resveratrol as compared with A2L. Assessment of 24-h post-treatment mitochondrial function shows that resveratrol is not mitotoxic as compared with A2L which exhibits mitotoxicity at its highest concentration.

Conclusions

Taken together, findings from this study showed that A2L possesses strong antiproliferative activity and its prospect in the management of hepatocellular carcinoma deserves further investigation.

Resveratrol and pterostilbene as a microRNA-mediated chemopreventive and therapeutic strategy in prostate cancer

Growing evidence indicates that deregulation of the epigenetic machinery comprising the microRNA (miRNA) network is a critical factor in the progression of various diseases, including cancer. Concurrently, dietary phytochemicals are being intensively studied for their miRNA-mediated health-beneficial properties, such as anti-inflammatory, cardioprotective, antioxidative, and anticancer properties. Available experimental data have suggested that dietary polyphenols may be effective miRNA-modulating chemopreventive and therapeutic agents. Moreover, noninvasive detection of changes in miRNA expression in liquid biopsies opens enormous possibilities for their clinical utilization as novel prognostic and predictive biomarkers. In our published studies, we identified resveratrol-regulated miRNA profiles in prostate cancer. Resveratrol downregulated the phosphatase and tensin homolog (PTEN)-targeting members of the oncogenic miR-17 family of miRNAs, which are overexpressed in prostate cancer. We have functionally validated the miRNA-mediated ability of resveratrol and its potent analog pterostilbene to rescue the tumor suppressor activity of PTEN in vitro and in vivo. Taken together, our findings implicate the use of resveratrol and its analogs as an attractive miRNA-mediated chemopreventive and therapeutic strategy in prostate cancer and the use of circulating miRNAs as potential predictive biomarkers for clinical development.

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

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

Metastasis-Associated Protein 1 Is Involved in Angiogenesis after Transarterial Chemoembolization Treatment

BACKGROUND

Transarterial chemoembolization (TACE), a well-established treatment for unresectable hepatocellular carcinoma (HCC), blocks the arterial blood supply to the tumor, which can be short-lived as development of collateral neovessels, leading to the failure of treatment. Metastasis-associated protein 1 (MTA1) is involved in development of tumors and metastases. However, the role of MTA1 in angiogenesis is still obscure.

METHODS

We detected the expression of MTA1 and hypoxia-inducible factor-1α (HIF-1α) and microvessel density (MVD) value in liver tumor tissues and tumor periphery before and after TACE treatment. Hepatocellular carcinoma cell line HepG2, tube formation assay, and chorioallantoic membrane (CAM) assay were applied to explore the mechanism of MTA1 in angiogenesis.

RESULTS

We found that expression of MTA1 increased after TACE treatment, especially in tumor periphery, which was accompanied by markedly elevated MVD value, indicating a significant correlation between MTA1 and MVD value. Moreover, MTA1 contributed to neovascularization of residual tumors. Cellular experiments further revealed that MTA1 increased the stability and the expression of HIF-1α, and overexpression of MTA1 enhanced tube formation and neovessels of chick embryos.

CONCLUSIONS

MTA1 is an active angiogenic regulator; our results shed light on better understanding in neovascularization, which are helpful to predict prognosis of TACE, and provide evidences for intervention to improve therapeutic effects on HCC.

Promising Role of Toll-Like Receptor 8 Agonist in Concert with Prostratin for Activation of Silent HIV

The persistence of latently HIV-infected cells in patients under combined antiretroviral treatment (cART) remains the major hurdle for HIV eradication. Thus far, individual compounds have not been sufficiently potent to reactivate latent virus and guarantee its elimination in vivo. Thus, we hypothesized that transcriptional enhancers, in concert with compounds triggering the innate immune system, are more efficient in reversing latency by creating a Th1 supportive milieu that acts against latently HIV-infected cells at various levels. To test our hypothesis, we screened six compounds on a coculture of latently infected cells (J-lat) and monocyte-derived dendritic cells (MDDCs). The protein kinase C (PKC) agonist prostratin, with a Toll-like receptor 8 (TLR8) agonist, resulted in greater reversion of HIV latency than any single compound. This combinatorial approach led to a drastic phenotypic and functional maturation of the MDDCs. Tumor necrosis factor (TNF) and cell-cell interactions were crucial for the greater reversion observed. Similarly, we found a greater potency of the combination of prostratin and TLR8 agonist in reversing HIV latency when applying it to primary cells of HIV-infected patients. Thus, we demonstrate here the synergistic interplay between TLR8-matured MDDCs and compounds acting directly on latently HIV-infected cells, targeting different mechanisms of latency, by triggering various signaling pathways. Moreover, TLR8 triggering may reverse exhaustion of HIV-specific cytotoxic T lymphocytes that might be essential for killing or constraining the latently infected cells.

IMPORTANCE

Curing HIV is the Holy Grail. The so-called "shock and kill" strategy relies on drug-mediated reversion of HIV latency and the subsequent death of those cells under combined antiretroviral treatment. So far, no compound achieves efficient reversal of latency or eliminates this latent reservoir. The compounds may not target all of the latency mechanisms in all latently infected cells. Moreover, HIV-associated exhaustion of the immune system hinders the efficient elimination of the reactivated cells. In this study, we demonstrated synergistic latency reversion by combining agonists for protein kinase C and Toll-like receptor 8 in a coculture of latently infected cells with myeloid dendritic cells. The drug prostratin stimulates directly the transcriptional machinery of latently infected cells, and the TLR8 agonist acts indirectly by maturing dendritic cells. These findings highlight the importance of the immune system and its activation, in combination with direct-acting compounds, to reverse latency.

Unraveling the Anticancer Effect of Curcumin and Resveratrol

Resveratrol and curcumin are natural products with important therapeutic properties useful to treat several human diseases, including cancer. In the last years, the number of studies describing the effect of both polyphenols against cancer has increased; however, the mechanism of action in all of those cases is not completely comprehended. The unspecific effect and the ability to interfere in assays by both polyphenols make this challenge even more difficult. Herein, we analyzed the anticancer activity of resveratrol and curcumin reported in the literature in the last 11 years, in order to unravel the molecular mechanism of action of both compounds. Molecular targets and cellular pathways will be described. Furthermore, we also discussed the ability of these natural products act as chemopreventive and its use in association with other anticancer drugs.

Resveratrol and pterostilbene epigenetically restore PTEN expression by targeting oncomiRs of the miR-17 family in prostate cancer

In recent years, not only has the role of miRNAs in cancer become increasingly clear but also their utilization as potential biomarkers and therapeutic targets has gained ground. Although the importance of dietary stilbenes such as resveratrol and pterostilbene as anti-cancer agents is well recognized, our understanding of their miRNA-targeting capabilities is still limited. In our previous study, we reported that resveratrol downregulates PTEN-targeting members of the oncogenic miR-17 family, which are overexpressed in prostate cancer. This study investigates the resveratrol and pterostilbene induced miRNA-mediated regulation of PTEN in prostate cancer. Here, we show that both compounds decrease the levels of endogenous as well as exogenously expressed miR-17, miR-20a and miR-106b thereby upregulating their target PTEN. Using functional luciferase reporter assays, we demonstrate that ectopically expressed miR-17, miR-20a and miR-106b directly target PTEN 3′UTR to reduce its expression, an effect rescued upon treatment with resveratrol and pterostilbene. Moreover, while stable lentiviral expression of miR-17/106a significantly decreased PTEN mRNA and protein levels and conferred survival advantage to the cells, resveratrol and more so pterostilbene was able to dramatically suppress these effects. Further, pterostilbene through downregulation of miR-17-5p and miR-106a-5p expression both in tumors and systemic circulation, rescued PTEN mRNA and protein levels leading to reduced tumor growth in vivo. Our findings implicate dietary stilbenes as an attractive miRNA-mediated chemopreventive and therapeutic strategy, and circulating miRNAs as potential chemopreventive and predictive biomarkers for clinical development in prostate cancer.

Dietary phytochemicals as epigenetic modifiers in cancer: Promise and challenges

The influence of diet and environment on human health has been known since ages. Plant-derived natural bioactive compounds (phytochemicals) have acquired an important role in human diet as potent antioxidants and cancer chemopreventive agents. In past few decades, the role of epigenetic alterations such as DNA methylation, histone modifications and non-coding RNAs in the regulation of mammalian genome have been comprehensively addressed. Although the effects of dietary phytochemicals on gene expression and signaling pathways have been widely studied in cancer, the impact of these dietary compounds on mammalian epigenome is rapidly emerging. The present review outlines the role of different epigenetic mechanisms in the regulation and maintenance of mammalian genome and focuses on the role of dietary phytochemicals as epigenetic modifiers in cancer. Above all, the review focuses on summarizing the progress made thus far in cancer chemoprevention with dietary phytochemicals, the heightened interest and challenges in the future.

Dietary pterostilbene is a novel MTA1-targeted chemopreventive and therapeutic agent in prostate cancer

Overexpression of the epigenetic modifier metastasis-associated protein 1 (MTA1) is associated with aggressive human prostate cancer. The purpose of this study was to determine MTA1- targeted chemopreventive and therapeutic efficacy of pterostilbene, a natural potent analog of resveratrol, in pre-clinical models of prostate cancer. Here, we show that high levels of MTA1 expression in Pten-loss prostate cooperate with key oncogenes, including c-Myc and Akt among others, to promote prostate cancer progression. Loss-of-function studies using human prostate cancer cells indicated direct involvement of MTA1 in inducing inflammation and epithelial-to-mesenchymal transition. Importantly, pharmacological inhibition of MTA1 by pterostilbene resulted in decreased proliferation and angiogenesis and increased apoptosis. This restrained prostatic intraepithelial neoplasia (PIN) formation in prostate-specific Pten heterozygous mice and reduced tumor development and progression in prostate-specific Pten-null mice. Our findings highlight MTA1 as a key upstream regulator of prostate tumorigenesis and cancer progression. More significantly, it offers pre-clinical proof for pterostilbene as a promising lead natural agent for MTA1-targeted chemopreventive and therapeutic strategy to curb prostate cancer.