Polyphenols: key issues involved in chemoprevention of prostate cancer

Recent advances in nanodelivery systems of resveratrol and their biomedical and food applications: a review

Resveratrol is a non-flavonoid polyphenolic compound with numerous functional properties, such as anticancer, anti-inflammation, anti-oxidation, anti-obesity and more. However, resveratrol's poor solubility within aqueous media and low stability usually lead to compromised bioavailability, ultimately limiting its uptake and applications. Nanodelivery technologies have been studied intensively due to their potential in effectively improving resveratrol properties, thereby providing promising solutions for enhancing the bioavailability of resveratrol. Thus, this article aimed to review the recent advances of resveratrol nanodelivery systems, specifically on the types of nanodelivery systems, the corresponding preparation principles, advantages, as well as potential limitations associated. Meanwhile, studies have also found that coupled with nanodelivery systems, the functional properties of resveratrol could trigger apoptosis in cancer cells and inflammatory cells through various signaling pathways. Therefore, this article will also lead into discussions on the application aspects of resveratrol nanodelivery systems, emphasizing toward the fields of biomedical and food sciences. Potential pitfalls of resveratrol nanodelivery systems, such as issues with toxicity and target release, as well as outlooks regarding resveratrol nanodelivery systems are included in the Conclusion section, in the hope to provide insights for relevant future research.

Dietary Intake of Polyphenols and All-Cause Mortality: A Systematic Review with Meta-Analysis

Polyphenols are secondary metabolites found in plants, foods, and drinks, occurring in small quantities and showcasing antioxidant and anti-inflammatory qualities. The primary polyphenols consist of flavonoids, phenolic acids, stilbenes, and lignans. However, there is currently no comprehensive quantitative analysis of epidemiological data on overall death rates. This systematic review with meta-analysis aims to identify the exposure-response relationship between dietary polyphenol intake and all-cause mortality. The literature was reviewed from its earliest study to May 2024, utilizing six distinct electronic databases. No specific criteria were used to choose participants based on the recruiting environment, their general health condition, country, or ethnicity. The inclusion criteria for studies were as follows: a longitudinal design, exposure to dietary polyphenols, all-cause mortality as the outcome, and hazard risk (HR) as the impact measure. The Newcastle-Ottawa Scale was used to evaluate the methodological rigor of the study. The hazard risks (HRs) and 95% confidence intervals (CIs) were estimated by pooling data using common effects models. A protocol has been registered on PROSPERO with the identification number CRD42024545524. The meta-analysis comprised seven cohort studies that involved 178,657 adult people aged 18 years and older. These studies examined the relationship between total dietary polyphenol consumption and the risk of all-cause death. The recruitment settings exclusively used community-based approaches, with a preference for Europe (71%) in terms of geographic distribution. The study's quality was assessed to be moderate to high. The meta-analysis showed consistent evidence that increased dietary exposure to polyphenols reduces the risk of all-cause mortality by 7% (HR 0.93, 95% CI 0.91-0.95, I2: 48%). Pooled data from the available evidence consistently show that individuals exposed to an antioxidant diet rich in polyphenol sources may be at lower risk of all-cause mortality.

Anti-proliferative, Pro-apoptotic, and Chemosensitizing Potential of 3-Acetyl-11-keto-β-boswellic Acid (AKBA) Against Prostate Cancer Cells

Prostate cancer incidences are rising worldwide at an alarming rate. Drug resistance and relapse are two major challenges in the treatment of prostate cancer. Therefore, new multimodal, safe, and effective therapeutic agents are urgently required which could effectively mitigate the menace of tumor recurrence and chemo-resistance. Plant-derived products are increasingly being utilized due to their antioxidant, antibacterial, and anti-tumor potential. In the current study, 3-acetyl-11-keto-β-boswellic acid, a triterpenoid isolated from plant Boswellia, was utilized to ascertain its chemotherapeutic potential against human prostate cancer cells. Various in vitro assays including cell viability, nuclear staining, mitochondria potential, reactive oxygen species (ROS) generation, and quantification of apoptosis, were performed for the evaluation of the cytotoxic potential of AKBA. We observed that AKBA (10-50 µM) dose-dependently suppressed cell proliferation and caused programmed cell death in PC3 cells via both intrinsic and extrinsic pathway. Intriguingly, AKBA was also found to chemosensitize PC3 cells in synergistic combination with doxorubicin. To the best of our knowledge, this is the first study to document the synergistic chemosensitizing impact of AKBA when combined with doxorubicin in prostate cancer cells.This showcases the potential of AKBA in combinatorial therapy or adjuvant therapy for the management of prostate cancer. In sum, our results suggested that AKBA is a promising drug-like molecule against prostate cancer. Our investigation introduces a novel perspective, elucidating a previously unexplored dimension, and uncovering a compelling chemosensitizing phenomenon along with a strong synergistic effect arising from the concurrent application of these two agents.

Targeting lncRNAs of colorectal cancers with natural products

Non-coding RNA (ncRNA) is one of the functional classes of RNA that has a regulatory role in various cellular processes, such as modulation of disease onset, progression, and prognosis. ncRNAs, such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), have been actively studied in recent years. The change in ncRNA levels is being actively studied in numerous human diseases, especially auto-immune disorders and cancers; however, targeting and regulating ncRNA with natural products to cure cancer has not been fully established. Recently many groups reported the relationship between ncRNA and natural products showing promising effects to serve as additional therapeutic approaches to cure cancers. This mini-review summarizes the aspects of lncRNAs related to cancer biology focusing on colorectal cancers that natural products can target.

Assessment of natural antioxidants' effect on PDT cytotoxicity through fluorescence microscopy image analysis

BACKGROUND AND OBJECTIVES

Photodynamic therapy (PDT) is a cancer treatment modality mediated by reactive oxygen species (ROS). However, the intracellular antioxidant defense system antagonizes PDT-generated ROS, impeding PDT efficacy. This study aimed to evaluate the enhancement of PDT cytotoxicity by its combination with natural antioxidants in pro-oxidant concentrations.

METHODS

A rich natural antioxidant mixture originating from Pinus halepensis bark extract was studied for its potential to enhance the efficacy of m-tetrahydroxyphenylchlorin (m-THPC)-PDT on LNCaP prostate cancer cells, in vitro. Various P. halepensis concentrations, at two different incubation times, were used in combination with m-THPC-PDT. Assessment of cellular viability and intracellular ROS levels evaluated the treatments' outcome. A novel method was developed for the assessment of the intracellular ROS levels, based on image analysis and data extraction from fluorescence microscopy images.

RESULTS

P. halepensis bark extract increased the intracellular ROS levels in a concentration-dependent but not in an incubation-dependent manner. The higher concentrations used (≥50 μg/ml) reduced cellular viability even by 50%. One hour pretreatment with 30 μg/ml P. halepensis before m-THPC-PDT exceeded the levels of cellular death by approximately 15%.

CONCLUSIONS

The results provided evidence of the cytotoxic effect of P. halepensis bark extract on LNCaP cells, showing the potential of P. halepensis to be used as an anticancer agent in prostate cancer treatment. The results also provided evidence of enhancement of m-THPC-PDT by P. halepensis bark extract showed the potential to be used as a supplementary agent to improve prostate cancer PDT treatment.

Targeting long non coding RNA by natural products: Implications for cancer therapy

In spite of achieving substantial progress in its therapeutic strategies, cancer-associated prevalence and mortality are persistently rising globally. However, most malignant cancers either cannot be adequately diagnosed at the primary phase or resist against multiple treatments such as chemotherapy, surgery, radiotherapy as well as targeting therapy. In recent decades, overwhelming evidences have provided more convincing words on the undeniable roles of long non-coding RNAs (lncRNAs) in incidence and development of various cancer types. Recently, phytochemical and nutraceutical compounds have received a great deal of attention due to their inhibitory and stimulatory effects on oncogenic and tumor suppressor lncRNAs respectively that finally may lead to attenuate various processes of cancer cells such as growth, proliferation, metastasis and invasion. Therefore, application of phytochemicals with anticancer characteristics can be considered as an innovative approach for treating cancer and increasing the sensitivity of cancer cells to standard prevailing therapies. The purpose of this review was to investigate the effect of various phytochemicals on regulation of lncRNAs in different human cancer and evaluate their capabilities for cancer treatment and prevention.

Arctigenin, an anti-tumor agent; a cutting-edge topic and up-to-the-minute approach in cancer treatment

Today, herbal-derived compounds are being increasingly studied in cancer treatment. Over the past decade, Arctigenin has been introduced as a bioactive dibenzylbutyrolactone lignan which is found in Chinese herbal medicines. In addition to anti-microbial, anti-inflammatory, immune-modulatory functions, Arctigenin has attracted growing attention due to its anti-tumor capabilities. It has been shown that Arctigenin can induce apoptosis and necrosis and abolish drug resistance in tumor cells by inducing apoptotic signaling pathways, caspases, cell cycle arrest, and the modulating proteasome. Moreover, Arctigenin mediates other anti-tumor functions through several mechanisms. It has been demonstrated that Arctigenin can act as an anti-inflammatory compound to inhibit inflammation in the tumor microenvironment. It also downregulates factors involved in tumor metastasis and angiogenesis, such as matrix metalloproteinases, N-cadherin, TGF-β, and VEGF. Additionally, Arctigenin, through modulation of MAPK signaling pathways and stress-related proteins, is able to abolish tumor cell growth in nutrient-deprived conditions. Due to the limited solubility of Arctigenin in water, it is suggested that modification of this compound through amino acid esterification can improve its pharmacogenetic properties. Collectively, it is hoped that using Arctigenin or its derivates might introduce new chemotherapeutic approaches in future treatment.

Targeted nanomedicine modalities for prostate cancer treatment

Prostate cancer (PC) is the second most common cause of death amongst men in the USA. Therapy of PC has been transformed in the past decade by introducing novel therapeutics, advanced functional imaging and diagnostic approaches, next generation sequencing, as well as improved application of existing therapies in localized PC. Treatment of PC at the different stages of the disease may include surgery, androgen deprivation therapy (ADT), chemotherapy and radiation therapy. However, although ADT has proven efficacious in PC treatment, its effectiveness may be temporary, as these tumors frequently develop molecular mechanisms of therapy resistance, which allow them to survive and proliferate even under conditions of testosterone deprivation, inhibition of androgen receptor signaling, or cytotoxic drug treatment. Importantly, ADT was found to induce key alterations which frequently result in the formation of metastatic tumors displaying a therapy refractory phenotype. Hence, to overcome these serious therapeutic impediments, novel PC cell-targeted therapeutic strategies are being developed. These include diverse platforms enabling specific enhanced antitumor drug uptake and increased intracellular accumulation. Studies have shown that these novel treatment modalities lead to enhanced antitumor activity and diminished systemic toxicity due to the use of selective targeting and decreased drug doses. The underlying mechanism of targeting and internalization is based upon the interaction between a selective ligand, conjugated to a drug-loaded nanoparticle or directly to an anti-cancer drug, and a specific plasma membrane biomarker, uniquely overexpressed on the surface of PC cells. Another targeted therapeutic approach is the delivery of unique anti-oncogenic signaling pathway-based therapeutic drugs, which are selectively cytotoxic to PC cells. The current paper reviews PC targeted modalities reported in the past 6 years, and discusses both the advantages and limitations of the various targeted treatment strategies.

Oxidative Stress, Plant Natural Antioxidants, and Obesity

Oxidative stress is important in the pathophysiology of obesity, altering regulatory factors of mitochondrial activity, modifying the concentration of inflammation mediators associated with a large number and size of adipocytes, promoting lipogenesis, stimulating differentiation of preadipocytes to mature adipocytes, and regulating the energy balance in hypothalamic neurons that control appetite. This review discusses the participation of oxidative stress in obesity and the important groups of compounds found in plants with antioxidant properties, which include (a) polyphenols such as phenolic acids, stilbenes, flavonoids (flavonols, flavanols, anthocyanins, flavanones, flavones, flavanonols, and isoflavones), and curcuminoids (b) carotenoids, (c) capsaicinoids and casinoids, (d) isothiocyanates, (e) catechins, and (f) vitamins. Examples are analyzed, such as resveratrol, quercetin, curcumin, ferulic acid, phloretin, green tea, Hibiscus Sabdariffa, and garlic. The antioxidant activities of these compounds depend on their activities as reactive oxygen species (ROS) scavengers and on their capacity to prevent the activation of NF-κB (nuclear factor κ-light-chain-enhancer of activated B cells), and reduce the expression of target genes, including those participating in inflammation. We conclude that natural compounds have therapeutic potential for diseases mediated by oxidative stress, particularly obesity. Controlled and well-designed clinical trials are still necessary to better know the effects of these compounds.

Molecular targets for the management of cancer using Curcuma longa Linn. phytoconstituents: A Review

Medicinal plants are being used for therapeutic purposes since the dawn of human civilization. The therapeutic efficacy of medicinal plants is due to the presence of wide range phytochemical constituents or secondary metabolites. The medicinal plants are traditionally used for several types of ailments. Even in those pathological conditions where other methods of treatment fail to work. Curcuma longa Linn is very common ingredient used as spice in foods as preservative and coloring material in different part of the world. It has been used as a home remedy for a variety of diseases. Curcuma longa and its isolated constituent curcumin are widely evaluated for anticancer activity. Curcumin possesses broad remedial potential due to its multi-targeting effect against many different carcinoma including leukemia, genitourinary cancers, gastrointestinal cancers and breast cancer etc. Hence, Curcumin has potential for the development of new medicine for the treatment of several diseases.

Resveratrol Nanoparticles: A Promising Therapeutic Advancement over Native Resveratrol

The importance of fruit-derived resveratrol (RES) in the treatment of various diseases has been discussed in various research publications. Those research findings have indicated the ability of the molecule as therapeutic in the context of in vitro and in vivo conditions. Mostly, the application of RES in in vivo conditions, encapsulation processes have been carried out using various nanoparticles that are made of biocompatible biomaterials, which are easily digested or metabolized, and RES is absorbed effectively. These biomaterials are non-toxic and are safe to be used as components in the biotherapeutics. They are made from naturally available by-products of food materials like zein or corn or components of the physiological system as with lipids. The versatility of the RES nanoparticles in their different materials, working range sizes, specificity in their targeting in various human diseases, and the mechanisms associated with them are discussed in this review.

Delivery Of Curcumin Nanoliposomes Using Surface Modified With CD133 Aptamers For Prostate Cancer

Aim

The aim of this study was to characterize curcumin (CUR)-loaded CD133 aptamer A15 liposomes for their antitumor activity in vitro and in vivo.

Methods

The modified CUR liposomes were prepared by the thin-film hydration technique.

Results

The particles showed spherical shape under electron microscopy with sizes <100 nm. Initial drug burst release was observed within 2 hrs and then the drug was continuously released over 48 hrs. No aggregation or precipitation of liposomes was observed during storage for 3 months. In vitro results showed that blank LPs had lower cellular cytotoxicity. Both liposomes of CUR (with or without A15 modified) exhibited a similar trend of cellular cytotoxicity at the same concentration. With the extension of incubation time, A15-CUR LPs showed a greater inhibitory effect on cells. Cell internalization in DU145 cells was higher for A15-CUR LPs than others. An in vivo study using DU145 prostate carcinoma bearing mice showed that A15-CUR LPs reduced tumor growth more than other forms of CUR.

Conclusion

These results indicate that A15 modified CUR liposomes are a promising candidate for antitumor drug delivery.

Curcumin and Cancer

Curcumin, a polyphenol extracted from Curcuma longa in 1815, has gained attention from scientists worldwide for its biological activities (e.g., antioxidant, anti-inflammatory, antimicrobial, antiviral), among which its anticancer potential has been the most described and still remains under investigation. The present review focuses on the cell signaling pathways involved in cancer development and proliferation, and which are targeted by curcumin. Curcumin has been reported to modulate growth factors, enzymes, transcription factors, kinase, inflammatory cytokines, and proapoptotic (by upregulation) and antiapoptotic (by downregulation) proteins. This polyphenol compound, alone or combined with other agents, could represent an effective drug for cancer therapy.

Encapsulation and Controlled Release of Resveratrol Within Functionalized Mesoporous Silica Nanoparticles for Prostate Cancer Therapy

Resveratrol (RES) is a naturally existing polyphenol which exhibits anti-oxidant, anti-inflammatory, and anti-cancer properties. In recent years, RES has attracted attention for its synergistic effect with other anti-cancer drugs for the treatment of drug resistant cancers. However, RES faces the issues of poor pharmacokinetics, stability and low solubility which limits its clinical application. In present study, RES has been loaded onto uniformly sized (~60 nm) mesoporous silica nanoparticles (MSNs) to improve its in vitro anti-proliferative activity and sensitization of Docatexal in hypoxia induced drug resistance in prostate cancer. RES was efficiently encapsulated within phosphonate (negatively charged) and amine (positively charged) modified MSNs. The effect of surface functionalization was studied on the loading, in vitro release, anti-proliferative and cytotoxic potential of RES using prostate cancer cell line. At pH 7.4 both free and NH2-MSNs loaded RES showed burst release which was plateaued with almost 90% of drug released in first 12 h. On the other hand, PO3-MSNs showed significantly slower release kinetics with only 50% drug release in first 12 h at pH 7.4. At pH 5.5, however, both the PO3-MSNs and NH2-MSNs showed significant control over release (around 40% less release compared with free RES in 24 h). Phosphonate modified MSNs significantly enhanced the anti-proliferative potential of RES with an IC50 of 7.15 μM as compared to 14.86 μM of free RES whereas amine modified MSNs didn't affect proliferation with an IC50 value higher than free RES (20.45 μM). Furthermore, RES loaded onto PO3-MSNs showed robust and dose dependent sensitization of Docatexal in hypoxic cell environment which was comparable to pure RES solution. This study provides an example of applicability of MSNs loaded with polyphenols such as RES as next generation anticancer formulations for treating drug resistant cancers such as prostate cancer.

Flaxseed Lignans as Important Dietary Polyphenols for Cancer Prevention and Treatment: Chemistry, Pharmacokinetics, and Molecular Targets

Cancer causes considerable morbidity and mortality across the world. Socioeconomic, environmental, and lifestyle factors contribute to the increasing cancer prevalence, bespeaking a need for effective prevention and treatment strategies. Phytochemicals like plant polyphenols are generally considered to have anticancer, anti-inflammatory, antiviral, antimicrobial, and immunomodulatory effects, which explain their promotion for human health. The past several decades have contributed to a growing evidence base in the literature that demonstrate ability of polyphenols to modulate multiple targets of carcinogenesis linking models of cancer characteristics (i.e., hallmarks and nutraceutical-based targeting of cancer) via direct or indirect interaction or modulation of cellular and molecular targets. This evidence is particularly relevant for the lignans, an ubiquitous, important class of dietary polyphenols present in high levels in food sources such as flaxseed. Literature evidence on lignans suggests potential benefit in cancer prevention and treatment. This review summarizes the relevant chemical and pharmacokinetic properties of dietary polyphenols and specifically focuses on the biological targets of flaxseed lignans. The consolidation of the considerable body of data on the diverse targets of the lignans will aid continued research into their potential for use in combination with other cancer chemotherapies, utilizing flaxseed lignan-enriched natural products.

Evaluation of Antioxidant, Antidiabetic and Antiobesity Potential of Selected Traditional Medicinal Plants

This study evaluated potential antidiabetic and antiobesity properties in vitro of selected medicinal plants. The hot water (WE) and ethanol extracts (EE) of sweet gale (Myrica gale L.), roseroot (Rhodiola rosea L.), sheep sorrel (Rumex acetosa L.), stinging nettles (Utrica dioica L.) and dandelion (Taraxacum officinale L.) were tested for total antioxidant capacity using ferric reducing antioxidant power (FRAP) and DPPH^• scavenging capacity assays, followed by α-amylase, α-glucosidase and formation of advanced glycation end products (AGE) inhibition assays in vitro. Myrica gale EE had the highest total phenolic content (12.4 mmol GAE/L), FRAP value (17.4 mmol TE/L) and DPPH^• scavenging activity (IC₅₀ = 3.28 mg/L). Similarly, Myrica gale also exhibited significantly lower IC₅₀ values for the percentage inhibition of α-amylase (IC₅₀ = 62.65 mg/L) and α-glucosidase (IC₅₀ = 27.20 mg/L) compared to acarbose (IC₅₀ = 91.71 mg/L; IC₅₀ = 89.50 mg/L, respectively) (p ≤ 0.05). The 3T3-L1 preadipocyte study also revealed that Myrica gale EE (54.8%) and stinging nettles (62.2% EE; 63.2% WE) significantly inhibited the adipogenesis in adipocytes in vitro (p ≤ 0.05). Polyphenols present in these medicinal plants have the potential to use in managing type 2 diabetes and obesity.

Muscadine grape skin extract inhibits prostate cancer cells by inducing cell-cycle arrest, and decreasing migration through heat shock protein 40

Previously we demonstrated that muscadine grape skin extract (MSKE), a natural product, significantly inhibited androgen-responsive prostate cancer cell growth by inducing apoptosis through the targeting of survival pathways. However, the therapeutic effect of MSKE on more aggressive androgen-independent prostate cancer remains unknown. This study examined the effects of MSKE treatment in metastatic prostate cancer using complementary PC-3 cells and xenograft model. MSKE significantly inhibited PC-3 human prostate cancer cell tumor growth in vitro and in vivo. The growth-inhibitory effect of MSKE appeared to be through the induction of cell-cycle arrest. This induction was accompanied by a reduction in the protein expression of Hsp40 and cell-cycle regulation proteins, cyclin D1 and NF-kBp65. In addition, MSKE induced p21 expression independent of wild-type p53 induced protein expression. Moreover, we demonstrate that MSKE significantly inhibited cell migration in PC-3 prostate cancer cells. Overall, these results demonstrate that MSKE inhibits prostate tumor growth and migration, and induces cell-cycle arrest by targeting Hsp40 and proteins involved in cell-cycle regulation and proliferation. This suggests that MSKE may also be explored either as a neo-adjuvant or therapeutic for castration resistant prostate cancer.

α-Viniferin activates autophagic apoptosis and cell death by reducing glucocorticoid receptor expression in castration-resistant prostate cancer cells

Prostate cancer (PCa) is one of the most commonly diagnosed urological malignancies. However, there are limited therapies for PCa patients who develop biochemical recurrence after androgen deprivation therapy (ADT). In the present study, we investigated the therapeutic efficacy and mechanism of α-Viniferin (KCV), an oligostilbene of trimeric resveratrol, against human PCa cells and found that it markedly inhibited the proliferation of LNCaP, DU145, and PC-3 cancer cells in a time- and dose-dependent manner, and had a strong cytotoxicity in non-androgen-dependent PCa cells. In addition, KCV inhibited AR downstream expression in LNCaP cells, and inhibited activation of GR signaling pathway in DU145 and PC-3. Further investigation indicated that KCV could induce cancer cell apoptosis through AMPK-mediated activation of autophagy, and inhibited GR expression in castration-resistant prostate cancer(CRPC). These findings suggest that KCV may prove to be a novel and effective therapeutic agent for the treatment of CRPC.

Antioxidant and Anti-Inflammatory Effects of Herbal Formula SC-E3 in Lipopolysaccharide-Stimulated RAW 264.7 Macrophages

SC-E3 is a novel herbal formula composed of five oriental medicinal herbs that are used to treat a wide range of inflammatory diseases in Korean traditional medicine. In this study, we sought to determine the effects of SC-E3 on free radical generation and inflammatory response in lipopolysaccharide- (LPS-) treated RAW 264.7 macrophages and the molecular mechanism involved. The ethanol extract of SC-E3 showed good free radical scavenging activity and inhibited LPS-induced reactive oxygen species generation. SC-E3 significantly inhibited the production of the LPS-induced inflammatory mediators, nitric oxide and prostaglandin E₂, by suppressing the expressions of inducible nitric oxide synthase and cyclooxygenase-2, respectively. SC-E3 also prevented the secretion of the proinflammatory cytokines, IL-1β, TNF-α, and IL-6, and inhibited LPS-induced NF-κB activation and the mitogen-activated protein kinase (MAPK) pathway. Furthermore, SC-E3 induced the expression of heme oxygenase-1 (HO-1) by promoting the nuclear translocation and transactivation of Nrf2. Taken together, these results suggest that SC-E3 has potent antioxidant and anti-inflammatory effects and that these effects are due to the inhibitions of NF-κB and MAPK and the induction of Nrf2-mediated HO-1 expression in macrophages. These findings provide scientific evidence supporting the potential use of SC-E3 for the treatment and prevention of various inflammatory diseases.

Metabolic syndrome and prostatic disease: potentially role of polyphenols in preventive strategies. A review

Benign prostatic hyperplasia and prostate cancer are two common urological diseases of the elderly. Scientific community has always looked for a link that could explain the correlation between the two diseases and the role of chronic inflammation in the pathogenesis of BPH and PCa. As shown by the reports of the two diseases relationship with oxidative stress and metabolic syndrome, the use of compounds with antioxidant action could therefore affect both the symptoms and their onset. Polyphenols appear to act not only against oxidative stress but also at different levels. The aim of this review is to evaluate the role of the most important polyphenols on these two urological diseases. As antioxidants these compounds seems to have a direct action on the cell cycle and hormone function, important for both prostate cancer and BPH. Despite a large number of articles about the relationship of the polyphenols with prostate cancer, very little evidence exists for BPH. Additional clinical trials or meta-analysis are necessary on this topic.

Arctigenin inhibits prostate tumor cell growth in vitro and in vivo

The low bioavailability of most phytochemicals limits their translation to humans. We investigated whether arctigenin, a novel anti-inflammatory lignan from the seeds of Arctium lappa, has favorable bioavailability/potency against prostate cancer. The anticarcinogenic activity of arctigenin was investigated both in vitro using the androgen-sensitive LNCaP and LAPC-4 human prostate cancer cells and pre-malignant WPE1-NA22 cells, and in vivo using xenograft mouse models. Arctigenin at lower doses (< 2μM) significantly inhibited the proliferation of LNCaP and LAPC-4 cells by 30-50% at 48h compared to control, and inhibited WPE1-NA22 cells by 75%, while did not affect normal prostate epithelial cells. Male severe combined immunodeficiency (SCID) mice were implanted subcutaneously with LAPC-4 cells for in vivo studies. In one experiment, the intervention started one week after tumor implantation. Mice received arctigenin at 50mg/kg (LD) or 100mg/kg (HD) b.w. daily or vehicle control by oral gavage. After 6 weeks, tumor growth was inhibited by 50% (LD) and 70% (HD) compared to control. A stronger tumor inhibitory effect was observed in a second experiment where arctigenin intervention started two weeks prior to tumor implantation. Arc was detectable in blood and tumors in Arc groups, with a mean value up to 2.0 μM in blood, and 8.3 nmol/g tissue in tumors. Tumor levels of proliferation marker Ki67, total and nuclear androgen receptor, and growth factors including VEGF, EGF, and FGF-β were significantly decreased by Arc, along with an increase in apoptosis marker of Bax/Bcl-2 ratio. Genes responsive to arctigenin were identified including TIMP3 and ZNF185, and microRNAs including miR-126-5p, and miR-21-5p. This study provides the first in vivo evidence of the strong anticancer activity of arctigenin in prostate cancer. The effective dose of arctigenin in vitro is physiologically achievable in vivo, which provides a high promise in its translation to human application.

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.

Bioactive natural products for chemoprevention and treatment of castration-resistant prostate cancer

Prostate cancer (PCa), a hormonally-driven cancer, ranks first in incidence and second in cancer related mortality in men in most Western industrialized countries. Androgen and androgen receptor (AR) are the dominant modulators of PCa growth. Over the last two decades multiple advancements in screening, treatment, surveillance and palliative care of PCa have significantly increased quality of life and survival following diagnosis. However, over 20% of patients initially diagnosed with PCa still develop an aggressive and treatment-refractory disease. Prevention or treatment for hormone-refractory PCa using bioactive compounds from marine sponges, mushrooms, and edible plants either as single agents or as adjuvants to existing therapy, has not been clinically successful. Major advancements have been made in the identification, testing and modification of the existing molecular structures of natural products. Additionally, conjugation of these compounds to novel matrices has enhanced their bio-availability; a big step towards bringing natural products to clinical trials. Natural products derived from edible plants (nutraceuticals), and common folk-medicines might offer advantages over synthetic compounds due to their broader range of targets, as compared to mostly single target synthetic anticancer compounds; e.g. kinase inhibitors. The use of synthetic inhibitors or antibodies that target a single aberrant molecule in cancer cells might be in part responsible for emergence of treatment refractory cancers. Nutraceuticals that target AR signaling (epigallocatechin gallate [EGCG], curcumin, and 5α-reductase inhibitors), AR synthesis (ericifolin, capsaicin and others) or AR degradation (betulinic acid, di-indolyl diamine, sulphoraphane, silibinin and others) are prime candidates for use as adjuvant or mono-therapies. Nutraceuticals target multiple pathophysiological mechanisms involved during cancer development and progression and thus have potential to simultaneously inhibit both prostate cancer growth and metastatic progression (e.g., inhibition of angiogenesis, epithelial-mesenchymal transition (EMT) and proliferation). Given their multi-targeting properties along with relatively lower systemic toxicity, these compounds offer significant therapeutic advantages for prevention and treatment of PCa. This review emphasizes the potential application of some of the well-researched natural compounds that target AR for prevention and therapy of PCa.

Effects of Resveratrol on p66Shc phosphorylation in cultured prostate cells

There is increasing evidence that diet plays a crucial role in age-related diseases and cancer. Oxidative stress is a conceivable link between diet and diseases, thus food antioxidants, counteracting the damage caused by oxidation, are potential tools for fight age-related diseases and cancer. Resveratrol (RSV), a polyphenolic antioxidant from grapes, has gained enormous attention particularly because of its ability to induce growth arrest and apoptosis in cancer cells, and it has been proposed as both chemopreventive and therapeutic agent for cancer and other diseases. Even though the effects of RSV have been studied in prostate cancer cells and animal models, little is known about its effects on normal cells and tissues. To address this issue, we have investigated the effects of RSV on EPN cells, a human non-transformed prostate cell line, focusing on the relationship between RSV and p66Shc, a redox enzyme whose activities strikingly intersect those of RSV. p66Shc activity is regulated by phosphorylation of serine 36 (Ser36) and has been related to mitochondrial oxidative stress, apoptosis induction, regulation of cell proliferation and migration. Here we show that RSV inhibits adhesion, proliferation and migration of EPN cells, and that these effects are associated to induction of dose- and time-dependent p66Shc-Ser36 phosphorylation and ERK1/2 de-phosphorylation. Moreover, we found that RSV is able to activate also p52Shc, another member of the Shc protein family. These data show that RSV affects non-transformed prostate epithelial cells and suggest that Shc proteins may be key contributors of RSV effects on prostate cells.

Studies on oxidants and antioxidants with a brief glance at their relevance to the immune system

Free radical generation occurs continuously within cells as a consequence of common metabolic processes. However, in high concentrations, whether from endogenous or exogenous sources, free radicals can lead to oxidative stress; a harmful process that cause serious damages to all biomolecules in our body hence impairs cell functions and even results in cell death and diseased states. Oxidative injuries accumulate over time and participate in cancer development, cardiovascular and neurodegenerative disorders as well as aging. Nature has bestowed the human body with a complex web of antioxidant defense system including enzymatic antioxidants like glutathione peroxidase and glutathione reductase, catalase and superoxide dismutase as well as non-enzymatic antioxidants such as thiol antioxidants, melatonin, coenzyme Q, and metal chelating proteins, which are efficient enough to fight against excessive free radicals. Also, nutrient antioxidants such as vitamin C, vitamin E, carotenoids, polyphenols, and trace elements are known to have high antioxidant potency to assist in minimizing harmful effects of reactive species. The immune system is also extremely vulnerable to oxidant and antioxidant balance as uncontrolled free radical production can impair its function and defense mechanism. The present paper reviews the ways by which free radicals form in the body and promote tissue damage, as well as the role of the antioxidants defense mechanisms. Finally, we will have a brief glance at oxidants and antioxidants relevance to the immune system.

Modulation of neurotrophic signaling pathways by polyphenols

Polyphenols are an important class of phytochemicals, and several lines of evidence have demonstrated their beneficial effects in the context of a number of pathologies including neurodegenerative disorders such as Alzheimer’s and Parkinson’s disease. In this report, we review the studies on the effects of polyphenols on neuronal survival, growth, proliferation and differentiation, and the signaling pathways involved in these neurotrophic actions. Several polyphenols including flavonoids such as baicalein, daidzein, luteolin, and nobiletin as well as nonflavonoid polyphenols such as auraptene, carnosic acid, curcuminoids, and hydroxycinnamic acid derivatives including caffeic acid phentyl ester enhance neuronal survival and promote neurite outgrowth in vitro, a hallmark of neuronal differentiation. Assessment of underlying mechanisms, especially in PC12 neuronal-like cells, reveals that direct agonistic effect on tropomyosin receptor kinase (Trk) receptors, the main receptors of neurotrophic factors including nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) explains the action of few polyphenols such as 7,8-dihydroxyflavone. However, several other polyphenolic compounds activate extracellular signal-regulated kinase (ERK) and phosphoinositide 3-kinase (PI3K)/Akt pathways. Increased expression of neurotrophic factors in vitro and in vivo is the mechanism of neurotrophic action of flavonoids such as scutellarin, daidzein, genistein, and fisetin, while compounds like apigenin and ferulic acid increase cyclic adenosine monophosphate response element-binding protein (CREB) phosphorylation. Finally, the antioxidant activity of polyphenols reflected in the activation of Nrf2 pathway and the consequent upregulation of detoxification enzymes such as heme oxygenase-1 as well as the contribution of these effects to the neurotrophic activity have also been discussed. In conclusion, a better understanding of the neurotrophic effects of polyphenols and the concomitant modulations of signaling pathways is useful for designing more effective agents for management of neurodegenerative diseases.

Recent developments in curcumin and curcumin based polymeric materials for biomedical applications: A review

Turmeric (Curcuma longa) is a popular Indian spice that has been used for centuries in herbal medicines for the treatment of a variety of ailments such as rheumatism, diabetic ulcers, anorexia, cough and sinusitis. Curcumin (diferuloylmethane) is the main curcuminoid present in turmeric and responsible for its yellow color. Curcumin has been shown to possess significant anti-inflammatory, anti-oxidant, anti-carcinogenic, anti-mutagenic, anticoagulant and anti-infective effects. This review summarizes and discusses recently published papers on the key biomedical applications of curcumin based materials. The highlighted studies in the review provide evidence of the ability of curcumin to show the significant vitro antioxidant, diabetic complication, antimicrobial, neuroprotective, anti-cancer activities and detection of hypochlorous acid, wound healing, treatment of major depression, healing of paracentesis, and treatment of carcinoma and optical detection of pyrrole properties. Hydrophobic nature of this polyphenolic compound along with its rapid metabolism, physicochemical and biological instability contribute to its poor bioavailability. To redress these problems several approaches have been proposed like encapsulation of curcumin in liposomes and polymeric micelles, inclusion complex formation with cyclodextrin, formation of polymer-curcumin conjugates, etc.

Resveratrol reduces the levels of circulating androgen precursors but has no effect on, testosterone, dihydrotestosterone, PSA levels or prostate volume. A 4-month randomised trial in middle-aged men

BACKGROUND

Resveratrol is a naturally occurring polyphenol with purported inhibitory effects on prostate growth and cancer development. A number of studies have demonstrated that resveratrol reduces prostate growth in animal models and reduces prostate cell growth in vitro. Based on these pre-clinical findings, interest in resveratrol is increasing in relation to the management of benign prostate hyperplasia (BPH) and prostate cancer. So far, no human trials have evaluated the effects of resveratrol on circulating androgens, prostate size, or biochemical markers of prostate size.

METHODS

In a randomized placebo controlled clinical study using two doses of resveratrol (150 mg or 1,000 mg resveratrol daily) for 4 months, we evaluated the effects on prostate size, prostate specific antigen (PSA) and sex steroid hormones in 66 middle-aged men suffering from the metabolic syndrome(MetS).

RESULTS

At baseline, prostate size and PSA were positively correlated (R = 0.34, P < 0.007) as was prostate size and age (R = 0.37, P < 0.003). Prostate size did not correlate with testosterone, free testosterone, dihydrotestosterone (DHT), or any other androgen precursor at baseline. The highest dose of resveratrol lowered the serum level of androstenedione 24% (P = 0.052), dehydroepiandrosterone (DHEA) 41% (P < 0.01), and dehydroepiandrosterone-sulphate (DHEAS) 50% (p<0.001), compared to the control group. However, prostate size and levels of PSA, testosterone, free testosterone and DHT remained unchanged.

CONCLUSION

In this population of middle-aged men suffering from MetS, high dose resveratrol (1,000 mg daily) administration for 4 months significantly lowered serum levels of the androgen precursors androstenedione, DHEA and DHEAS, whereas prostate size and circulating levels of PSA, testosterone, free testosterone, and dihydrotestosterone were unaffected. The present study suggests that resveratrol does not affect prostate volume in healthy middle-aged men as measured by PSA levels and CT acquired prostate volumes. Consequently, we find no support for the use of resveratrol in the treatment of benign prostate hyperplasia.

MicroRNA-Sequence Profiling Reveals Novel Osmoregulatory MicroRNA Expression Patterns in Catadromous Eel Anguilla marmorata

MicroRNAs (miRNAs) are a class of endogenous small non-coding RNAs that regulate gene expression by post-transcriptional repression of mRNAs. Recently, several miRNAs have been confirmed to execute directly or indirectly osmoregulatory functions in fish via translational control. In order to clarify whether miRNAs play relevant roles in the osmoregulation of Anguilla marmorata, three sRNA libraries of A. marmorata during adjusting to three various salinities were sequenced by Illumina sRNA deep sequencing methods. Totally 11,339,168, 11,958,406 and 12,568,964 clear reads were obtained from 3 different libraries, respectively. Meanwhile, 34 conserved miRNAs and 613 novel miRNAs were identified using the sequence data. MiR-10b-5p, miR-181a, miR-26a-5p, miR-30d and miR-99a-5p were dominantly expressed in eels at three salinities. Totally 29 mature miRNAs were significantly up-regulated, while 72 mature miRNAs were significantly down-regulated in brackish water (10‰ salinity) compared with fresh water (0‰ salinity); 24 mature miRNAs were significantly up-regulated, while 54 mature miRNAs were significantly down-regulated in sea water (25‰ salinity) compared with fresh water. Similarly, 24 mature miRNAs were significantly up-regulated, while 45 mature miRNAs were significantly down-regulated in sea water compared with brackish water. The expression patterns of 12 dominantly expressed miRNAs were analyzed at different time points when the eels transferred from fresh water to brackish water or to sea water. These miRNAs showed differential expression patterns in eels at distinct salinities. Interestingly, miR-122, miR-140-3p and miR-10b-5p demonstrated osmoregulatory effects in certain salinities. In addition, the identification and characterization of differentially expressed miRNAs at different salinities can clarify the osmoregulatory roles of miRNAs, which will shed lights for future studies on osmoregulation in fish.

A novel long noncoding RNA AK001796 acts as an oncogene and is involved in cell growth inhibition by resveratrol in lung cancer

Lung cancer is the most common form of cancer throughout the world. The specific targeting of long noncoding RNAs (lncRNAs) by resveratrol opened a new avenue for cancer chemoprevention. In this study, we found that 21 lncRNAs were upregulated and 19 lncRNAs were downregulated in lung cancer A549 cells with 25 μmol/L resveratrol treatment determined by microarray analysis. AK001796, the lncRNA with the most clearly altered expression, was overexpressed in lung cancer tissues and cell lines, but its expression was downregulated in resveratrol-treated lung cancer cells. By monitoring cell proliferation and growth in vitro and tumor growth in vivo, we observed a significant reduction in cell viability in lung cancer cells and a slow growth in the tumorigenesis following AK001796 knockdown. We also found that AK001796 knockdown caused a cell-cycle arrest, with significant increases in the percentage of cells in G0/G1 in lung cancer cells. By using cell cycle pathway-specific PCR arrays, we detected changes in a number of cell cycle-related genes related to lncRNA AK001796 knockdown. We further investigated whether AK001796 participated in the anticancer effect of resveratrol and the results showed that reduced lncRNA AK001796 level potentially impaired the inhibitory effect of resveratrol on cell proliferation. To our knowledge, this is the first study to report the changes in an lncRNA expression profile induced by resveratrol in lung cancer.

Roles of autophagy induced by natural compounds in prostate cancer

Autophagy is a homeostatic mechanism through which intracellular organelles and proteins are degraded and recycled in response to increased metabolic demand or stress. Autophagy dysfunction is often associated with many diseases, including cancer. Because of its role in tumorigenesis, autophagy can represent a new therapeutic target for cancer treatment. Prostate cancer (PCa) is one of the most common cancers in aged men. The evidence on alterations of autophagy related genes and/or protein levels in PCa cells suggests a potential implication of autophagy in PCa onset and progression. The use of natural compounds, characterized by low toxicity to normal tissue associated with specific anticancer effects at physiological levels in vivo, is receiving increasing attention for prevention and/or treatment of PCa. Understanding the mechanism of action of these compounds could be crucial for the development of new therapeutic or chemopreventive options. In this review we focus on the current evidence showing the capacity of natural compounds to exert their action through autophagy modulation in PCa cells.

Antioxidant, α-glucosidase inhibitory and anti-inflammatory effects of aerial parts extract from Korean crowberry (Empetrum nigrum var. japonicum)

Crowberry (Empetrum nigrum L.) is a wild berry commonly found in the northern hemisphere. Crowberry fruits have been suggested as good resources for functional applications in the cosmetic and pharmaceutical industries, but the high polyphenolic content in crowberry leaves also indicates crowberry aerial parts as potential dietary health supplements. In this study, therefore, the biological activities of the aerial parts of Korean crowberry (E. nigrum var. japonicum) were investigated. Antioxidant activity was measured by three different assays on DPPH free radical scavenging, reducing power, and total antioxidant capacities. Dose-dependent antioxidant activities were exhibited by crude methanol extract and its fractions, suggesting that the crude methanol extract and EtOAc fraction possessed strong antioxidant activities and capacities. In addition, the crude methanol extract and EtOAc strongly inhibited α-glucosidase activity and suppressed the secretion of pro-inflammatory mediator and nitrite oxide from LPS-stimulated RAW 264.7 cells. These findings provide valuable evidence for the potential of such parts as good dietary sources of natural antioxidant, α-glucosidase inhibitory, and anti-inflammatory components, suggesting that using the non-edible parts (e.g., leaves and stems) of crowberry can be a potential natural avenue for improving human health.

Arctigenin in combination with quercetin synergistically enhances the antiproliferative effect in prostate cancer cells

SCOPE

We investigated whether a combination of two promising chemopreventive agents arctigenin (Arc) and quercetin (Q) increases the anticarcinogenic potency at lower concentrations than necessary when used individually in prostate cancer.

METHODS AND RESULTS

Androgen-dependent LAPC-4 and LNCaP prostate cancer cells were treated with low doses of Arc and Q alone or in combination for 48 h. The antiproliferative activity of Arc was 10- to 20-fold stronger than Q in both cell lines. Their combination synergistically enhanced the antiproliferative effect, with a stronger effect in androgen receptor (AR) wild-type LAPC-4 cells than in AR mutated LNCaP cells. Arc demonstrated a strong ability to inhibit AR protein expression in LAPC-4 cells. The combination treatment significantly inhibited both AR and PI3K/Akt pathways compared to control. A protein array analysis revealed that the mixture targets multiple pathways particularly in LAPC-4 cells including Stat3 pathway. The mixture significantly inhibited the expression of several oncogenic microRNAs including miR-21, miR-19b, and miR-148a compared to control. The mixture also enhanced the inhibition of cell migration in both cell lines compared to individual compounds tested.

CONCLUSION

The combination of Arc and Q that target similar pathways, at low physiological doses, provides a novel regimen with enhanced chemoprevention in prostate cancer.

Wine polyphenols exert antineoplasic effect on androgen resistant PC-3 cell line through the inhibition of the transcriptional activity of COX-2 promoter mediated by NF-kβ

OBJECTIVE

Mediterranean diet may play a role in the prevention of prostate cancer (PCa) development and progression. Cyclooxygenase-2 (COX-2) expression is associated with increased cellular proliferation, prevents apoptosis and favors tumor invasion. We intend to clarify whether resveratrol and other polyphenols effectively inhibit COX-2 activity and induce apoptosis in hormone-resistant PC-3 cell line.

MATERIAL AND METHOD

PC-3 cells were cultured and treated with different concentrations of gallic acid, tannic acid, quercetin, and resveratrol in presence of phorbol myristate acetate (PMA; 50 μg/ml) that induces COX-2 expression. Total RNA was extracted and COX-2 expression was analyzed by relative quantification real-time PCR (ΔΔCt method). COX-2 activity was determined by PGE-2 detection using ELISA. Caspase 3/7 luminescence assay was used to disclose apoptosis. Transitory transfection with short human COX-2 (phPES2 -327/+59) and p5xNF-kβ-Luc plasmids determined COX-2 promoter activity and specifically that dependant of NF-kβ.

RESULTS

COX-2 expression was not modified in media devoid of PMA. However, under PMA induction tannic acid (2.08 ±.21), gallic acid (2.46 ±.16), quercetin (1.78 ±.14) and resveratrol (1.15 ±.16) significantly inhibited COX-2 mRNA with respect to control (3.14 ±.07), what means a 34%, 23%, 46% and 61% reduction, respectively. The inhibition in the levels of PGE-2 followed a similar pattern. All compounds studied induced apoptosis at 48 h, although at a different rate. PMA caused a rise in activity 7.4 ±.23 times phPES2 -327/+59 and 2.0 ±.1 times p5xNF-kβ-Luc at 6h compared to basal. Resveratrol suppressed these effects 17.1 ±.21 and 32.4 ±.18 times, respectively. Similarly, but to a lesser extent, the rest of evaluated polyphenols diminished PMA inductor effect on the activity of both promoters.

CONCLUSIONS

Polyphenols inhibit transcriptional activity of COX-2 promoter mediated by NF-kβ. This effect could explain, at least in part, the induction of apoptosis in vitro by these substances in castration resistant PCa.

Anti-cancer activity of curcumin loaded nanoparticles in prostate cancer

Prostate cancer is the most commonly diagnosed cancer disease in men in the Unites States and its management remains a challenge in everyday oncology practice. Thus, advanced therapeutic strategies are required to treat prostate cancer patients. Curcumin (CUR) is a promising anticancer agent for various cancer types. The objective of this study was to evaluate therapeutic potential of novel poly(lactic-co-glycolic acid)- CUR nanoparticles (PLGA-CUR NPs) for prostate cancer treatment. Our results indicate that PLGA-CUR NPs efficiently internalize in prostate cancer cells and release biologically active CUR in cytosolic compartment of cells for effective therapeutic activity. Cell proliferation (MTS), clonogenic, and Western blot analyses reveal that PLGA-CUR NPs can effectively inhibit proliferation and colony formation ability of prostate cancer cells than free CUR. PLGA-CUR NPs showed superior tumor regression compared to CUR in xenograft mice. Further investigations reveal that PLGA-CUR NPs inhibit nuclear β-catenin and AR expression in cells and in tumor xenograft tissues. It also suppresses STAT3 and AKT phosphorylation and leads to apoptosis via inhibition of key anti-apoptotic proteins, Mcl-1, Bcl-xL and caused induction of PARP cleavage. Additionally, significant downregulation of oncogenic miR21 and up-regulation of miR-205 was observed with PLGA-CUR NPs treatment as determined by RT-PCR and in situ hybridization analyses. A superior anti-cancer potential was attained with PSMA antibody conjugated PLGA-CUR NPs in prostate cancer cells and a significant tumor targeting of (131)I labeled PSMA antibody was achieved with PLGA-CUR NPs in prostate cancer xenograft mice model. In conclusion, PLGA-CUR NPs can significantly accumulate and exhibit superior anticancer activity in prostate cancer.

Effects of resveratrol and other wine polyphenols on the proliferation, apoptosis and androgen receptor expression in LNCaP cells

PURPOSE

To address the effect of resveratrol and other red wine polyphenols on cell proliferation, apoptosis and androgen receptor (AR) expression in human prostate cancer LNCaP cells.

MATERIALS AND METHODS

LNCaP cells (5 × 102) were cultured in microtiter plate modules and treated with gallic acid, tannic acid and quercetin (1, 5 and 10 μM), rutin and morin (25, 50 and 75 μM) and resveratrol (5, 10 and 25 μM). To address the extent of proliferation at 24, 48, 72 and 96 hours, a colorimetric immunoassay method was used. An activity caspase 3/7 detection assay was used to disclose apoptosis at 24, 48 and 72 hours. AR mARN levels were determined by real time RT-PCR.

RESULTS

All polyphenols studied significantly inhibited (P<.05) cell proliferation compared to control. However, there were moderate differences between them. Resveratrol was the strongest inhibitor at different times and doses. Also, caspase-3 and caspase-7 activity was significantly higher (P<.05) than control in the presence of all the compounds, but the earlier response was achieved by resveratrol. Resveratrol, quercetin and morin were the only nutrients that significantly inhibited AR mRNA expression. Again resveratrol produced the highest inhibition (90-250 times less than control), followed by morin (67-100 times) and quercetin (55-91 times).

CONCLUSIONS

All polyphenols studied showed important antiproliferative effects and induced apoptosis when added to LNCaP cells culture. We confirm that resveratrol, morin and quercetin may achieve such effect through reduced expression of AR. The synergistic effects of these compounds and their potential to prevent progression of hormone-dependent prostate cancer merit further study.

Gefitinib and luteolin cause growth arrest of human prostate cancer PC-3 cells via inhibition of cyclin G-associated kinase and induction of miR-630

Cyclin G-associated kinase (GAK), a key player in clathrin-mediated membrane trafficking, is overexpressed in various cancer cells. Here, we report that GAK expression is positively correlated with the Gleason score in surgical specimens from prostate cancer patients. Embryonic fibroblasts from knockout mice expressing a kinase-dead (KD) form of GAK showed constitutive hyper-phosphorylation of the epidermal growth factor receptor (EGFR). In addition to the well-known EGFR inhibitors gefitinib and erlotinib, the dietary flavonoid luteolin was a potent inhibitor of the Ser/Thr kinase activity of GAK in vitro. Co-administration of luteolin and gefitinib to PC-3 cells had a greater effect on cell viability than administration of either compound alone; this decrease in viability was associated with drastic down-regulation of GAK protein expression. A comprehensive microRNA array analysis revealed increased expression of miR-630 and miR-5703 following treatment of PC-3 cells with luteolin and/or gefitinib, and exogenous overexpression of miR-630 caused growth arrest of these cells. GAK appears to be essential for cell death because co-administration of gefitinib and luteolin to EGFR-deficient U2OS osteosarcoma cells also had a greater effect on cell viability than administration of either compound alone. Taken together, these findings suggest that GAK may be a new therapeutic target for prostate cancer and osteosarcoma.

Polyphenol intake and mortality risk: a re-analysis of the PREDIMED trial

BACKGROUND

Polyphenols may lower the risk of cardiovascular disease (CVD) and other chronic diseases due to their antioxidant and anti-inflammatory properties, as well as their beneficial effects on blood pressure, lipids and insulin resistance. However, no previous epidemiological studies have evaluated the relationship between the intake of total polyphenols intake and polyphenol subclasses with overall mortality. Our aim was to evaluate whether polyphenol intake is associated with all-cause mortality in subjects at high cardiovascular risk.

METHODS

We used data from the PREDIMED study, a 7,447-participant, parallel-group, randomized, multicenter, controlled five-year feeding trial aimed at assessing the effects of the Mediterranean Diet in primary prevention of cardiovascular disease. Polyphenol intake was calculated by matching food consumption data from repeated food frequency questionnaires (FFQ) with the Phenol-Explorer database on the polyphenol content of each reported food. Hazard ratios (HR) and 95% confidence intervals (CI) between polyphenol intake and mortality were estimated using time-dependent Cox proportional hazard models.

RESULTS

Over an average of 4.8 years of follow-up, we observed 327 deaths. After multivariate adjustment, we found a 37% relative reduction in all-cause mortality comparing the highest versus the lowest quintiles of total polyphenol intake (hazard ratio (HR) = 0.63; 95% CI 0.41 to 0.97; P for trend = 0.12). Among the polyphenol subclasses, stilbenes and lignans were significantly associated with reduced all-cause mortality (HR =0.48; 95% CI 0.25 to 0.91; P for trend = 0.04 and HR = 0.60; 95% CI 0.37 to 0.97; P for trend = 0.03, respectively), with no significant associations apparent in the rest (flavonoids or phenolic acids).

CONCLUSIONS

Among high-risk subjects, those who reported a high polyphenol intake, especially of stilbenes and lignans, showed a reduced risk of overall mortality compared to those with lower intakes. These results may be useful to determine optimal polyphenol intake or specific food sources of polyphenols that may reduce the risk of all-cause mortality.

CLINICAL TRIAL REGISTRATION

ISRCTN35739639.

Bladder cancer and urothelial impairment: the role of TRPV1 as potential drug target

Urothelium, in addition to its primary function of barrier, is now understood to act as a complex system of cell communication that exhibits specialized sensory properties in the regulation of physiological or pathological stimuli. Furthermore, it has been hypothesized that bladder inflammation and neoplastic cell growth, the two most representative pathological conditions of the lower urinary tract, may arise from a primary defective urothelial lining. Transient receptor potential vanilloid channel 1 (TRPV1), a receptor widely distributed in lower urinary tract structures and involved in the physiological micturition reflex, was described to have a pathophysiological role in inflammatory conditions and in the genesis and development of urothelial cancer. In our opinion new compounds, such as curcumin, the major component of turmeric Curcuma longa, reported to potentiate the effects of the chemotherapeutic agents used in the management of recurrent urothelial cancer in vitro and also identified as one of several compounds to own the vanillyl structure required to work like a TRPV1 agonist, could be thought as complementary in the clinical management of both the recurrences and the inflammatory effects caused by the endoscopic resection or intravesical chemotherapy administration or could be combined with adjuvant agents to potentiate their antitumoral effect.

Inhibitors of apoptosis proteins in experimental benign prostatic hyperplasia: effects of serenoa repens, selenium and lycopene

BACKGROUND

The apoptosis machinery is a promising target against benign prostatic hyperplasia (BPH). Inhibitors of apoptosis proteins (IAPs) modulate apoptosis by direct inhibition of caspases. Serenoa Repens (SeR) may be combined with other natural compounds such as Lycopene (Ly) and Selenium (Se) to maximize its therapeutic activity in BPH. We investigated the effects of SeR, Se and Ly, alone or in association, on the expression of four IAPs, cIAP-1, cIAP-2, NAIP and survivin in rats with experimental testosterone-dependent BPH. Moreover, caspase-3, interleukin-6 (IL-6) and prostate specific membrane antigen (PSMA) have been evaluated.Rats were administered, daily, with testosterone propionate (3 mg/kg/sc) or its vehicle for 14 days. Testosterone injected animals (BPH) were randomized to receive vehicle, SeR (25 mg/kg/sc), Se (3 mg/kg/sc), Ly (1 mg/kg/sc) or the SeR-Se-Ly association for 14 days. Animals were sacrificed and prostate removed for analysis.

RESULTS

BPH animals treated with vehicle showed unchanged expression of cIAP-1 and cIAP-2 and increased expression of NAIP, survivin, caspase-3, IL-6 and PSMA levels when compared with sham animals. Immunofluorescence studies confirmed the enhanced expression of NAIP and survivin with a characteristic pattern of cellular localization. SeR-Se-Ly association showed the highest efficacy in reawakening apoptosis; additionally, this therapeutic cocktail significantly reduced IL-6 and PSMA levels. The administration of SeR, Se and Ly significantly blunted prostate overweight and growth; moreover, the SeR-Se-Ly association was most effective in reducing prostate enlargement and growth by 43.3% in treated animals.

CONCLUSIONS

The results indicate that IAPs may represent interesting targets for drug therapy of BPH.

Genistein downregulates onco-miR-1260b and upregulates sFRP1 and Smad4 via demethylation and histone modification in prostate cancer cells

Background:

Recently several microRNAs (miRNAs) have been found to be regulated by genistein in cancer cells. In this study, we focused on the gene regulatory effect of genistein on microRNA and its target genes in prostate cancer (PC).

Methods:

Initially, we investigated the effect of genistein on prostate cancer cells and identified that the expression of miRNA-1260b was decreased by genistein. We performed functional analyses and investigated the relationship between miRNA-1260b expression and prostate cancer patient outcomes. Two target genes (sFRP1 and Smad4) of miR-1260b were identified based on computer algorithm and 3′UTR luciferase assay was carried out to determine direct miRNA regulation of the genes.

Results:

Genistein promoted apoptosis while inhibiting prostate cancer cell proliferation, invasion and TCF reporter activity in PC cells. MiR-1260b was highly expressed in prostate cancer tissues and significantly downregulated by genistein in PC cells. After knocking down miR-1260b, cell proliferation, invasion, migration and TCF reporter activity were decreased in PC cells. Western analysis and 3′UTR luciferase assay showed that the two target genes (sFRP1 and Smad4) were directly regulated by miR-1260b. The expression of sFRP1 and Smad4 was significantly decreased in prostate cancer tissues. Genistein also increased expression of these two genes via DNA demethylation and histone modifications.

Conclusions:

Our data suggest that genistein exerts its anti-tumour effect via downregulation of miR-1260b that targeted sRRP1 and Smad4 genes in prostate cancer cells. The expression of sFRP1 and Smad4 was also modulated by genistein via DNA methylation or histone modifications in PC cell lines.