Reduced growth and integrin expression of prostate cells cultured with lycopene, vitamin E and fish oil in vitro

Molecular Basis of Prostate Cancer and Natural Products as Potential Chemotherapeutic and Chemopreventive Agents

Prostate cancer is the second most common malignant cancer in males. It involves a complex process driven by diverse molecular pathways that closely related to the survival, apoptosis, metabolic and metastatic characteristics of aggressive cancer. Prostate cancer can be categorized into androgen dependent prostate cancer and castration-resistant prostate cancer and cure remains elusive due to the developed resistance of the disease. Natural compounds represent an extraordinary resource of structural scaffolds with high diversity that can offer promising chemical agents for making prostate cancer less devastating and curable. Herein, those natural compounds of different origins and structures with potential cytotoxicity and/or in vivo anti-tumor activities against prostate cancer are critically reviewed and summarized according to the cellular signaling pathways they interfere. Moreover, the anti-prostate cancer efficacy of many nutrients, medicinal plant extracts and Chinese medical formulations were presented, and the future prospects for the application of these compounds and extracts were discussed. Although the failure of conventional chemotherapy as well as involved serious side effects makes natural products ideal candidates for the treatment of prostate cancer, more investigations of preclinical and even clinical studies are necessary to make use of these medical substances reasonably. Therefore, the elucidation of structure-activity relationship and precise mechanism of action, identification of novel potential molecular targets, and optimization of drug combination are essential in natural medicine research and development.

Germline genetic variation in prostate susceptibility does not predict outcomes in the chemoprevention trials PCPT and SELECT

BACKGROUND

The development of prostate cancer can be influenced by genetic and environmental factors. Numerous germline SNPs influence prostate cancer susceptibility. The functional pathways in which these SNPs increase prostate cancer susceptibility are unknown. Finasteride is currently not being used routinely as a chemoprevention agent but the long term outcomes of the PCPT trial are awaited. The outcomes of the SELECT trial have not recommended the use of chemoprevention in preventing prostate cancer. This study investigated whether germline risk SNPs could be used to predict outcomes in the PCPT and SELECT trial.

METHODS

Genotyping was performed in European men entered into the PCPT trial (n = 2434) and SELECT (n = 4885). Next generation genotyping was performed using Affymetrix® Eureka™ Genotyping protocols. Logistic regression models were used to test the association of risk scores and the outcomes in the PCPT and SELECT trials.

RESULTS

Of the 100 SNPs, 98 designed successfully and genotyping was validated for samples genotyped on other platforms. A number of SNPs predicted for aggressive disease in both trials. Men with a higher polygenic score are more likely to develop prostate cancer in both trials, but the score did not predict for other outcomes in the trial.

CONCLUSION

Men with a higher polygenic risk score are more likely to develop prostate cancer. There were no interactions of these germline risk SNPs and the chemoprevention agents in the SELECT and PCPT trials.

Caffeic acid phenethyl ester guards against benign prostate hypertrophy in rats: Role of IGF-1R/protein kinase-B (Akt)/β-catenin signaling

Benign prostate hypertrophy (BPH) is among the most common diseases with a huge impact on the quality of life of elderly men. There is a current need for the development of well-tolerated and effective preventive strategies to improve the clinical outcome. Caffeic acid phenethyl ester (CAPE) is an important active ingredient isolated from honey-bee propolis with potent anti-proliferative, anti-inflammatory and antioxidant effects. These properties promote CAPE as a promising candidate to be tested as an alternative therapy for BPH, which is still uninvestigated. Herein, we tested the ability of CAPE to guard against testosterone-induced BPH and investigated the involvement of IGF1-R/Akt/β-catenin signaling as a protective mechanism in testosterone-induced BPH rat model. Treatment with CAPE reduced testosterone-induced increase in the prostate index and histopathological alterations. In addition, co-treatment with CAPE significantly suppressed insulin-like growth factor-1 receptor (IGF-1R)/Akt/β-catenin/cyclinD1 axis as well as tumor necrosis factor-α level and nuclear factor (NF)-kB activity. Furthermore, the treatment with CAPE replenished the antioxidant defense systems, superoxide dismutase (SOD) and reduced glutathione (GSH) with subsequent reduction in prostate tissue lipid peroxides. This study highlights the potential merit of CAPE-enriched propolis formulations to protect elderly men against the development of BPH. © 2018 IUBMB Life, 70(6):519-528, 2018.

Fish-Derived Omega-3 Fatty Acids and Prostate Cancer: A Systematic Review

BACKGROUND

The use of natural health products in prostate cancer (PrCa) is high despite a lack of evidence with respect to safety and efficacy. Fish-derived omega-3 fatty acids possess anti-inflammatory effects and preclinical data suggest a protective effect on PrCa incidence and progression; however, human studies have yielded conflicting results.

METHODS

A search of OVID MEDLINE, Pre-MEDLINE, Embase, and the Allied and Complementary Medicine Database (AMED) was completed for human interventional or observational data assessing the safety and efficacy of fish-derived omega-3 fatty acids in the incidence and progression of PrCa.

RESULTS

Of 1776 citations screened, 54 publications reporting on 44 studies were included for review and analysis: 4 reports of 3 randomized controlled trials, 1 nonrandomized clinical trial, 20 reports of 14 cohort studies, 26 reports of 23 case-control studies, and 3 case-cohort studies. The interventional studies using fish oil supplements in patients with PrCa showed no impact on prostate-specific antigen levels; however, 2 studies showed a decrease in inflammatory or other cancer markers. A small number of mild adverse events were reported and interactions with other interventions were not assessed. Cohort and case-control studies assessing the relationship between dietary fish intake and the risk of PrCa were equivocal. Cohort studies assessing the risk of PrCa mortality suggested an association between higher intake of fish and decreased risk of prostate cancer-related death.

CONCLUSIONS

Current evidence is insufficient to suggest a relationship between fish-derived omega-3 fatty acid and risk of PrCa. An association between higher omega-3 intake and decreased PrCa mortality may be present but more research is needed. More intervention trials or observational studies with precisely measured exposure are needed to assess the impact of fish oil supplements and dietary fish-derived omega-3 fatty acid intake on safety, PrCa incidence, treatment, and progression.

A multi-targeted approach to suppress tumor-promoting inflammation

Cancers harbor significant genetic heterogeneity and patterns of relapse following many therapies are due to evolved resistance to treatment. While efforts have been made to combine targeted therapies, significant levels of toxicity have stymied efforts to effectively treat cancer with multi-drug combinations using currently approved therapeutics. We discuss the relationship between tumor-promoting inflammation and cancer as part of a larger effort to develop a broad-spectrum therapeutic approach aimed at a wide range of targets to address this heterogeneity. Specifically, macrophage migration inhibitory factor, cyclooxygenase-2, transcription factor nuclear factor-κB, tumor necrosis factor alpha, inducible nitric oxide synthase, protein kinase B, and CXC chemokines are reviewed as important antiinflammatory targets while curcumin, resveratrol, epigallocatechin gallate, genistein, lycopene, and anthocyanins are reviewed as low-cost, low toxicity means by which these targets might all be reached simultaneously. Future translational work will need to assess the resulting synergies of rationally designed antiinflammatory mixtures (employing low-toxicity constituents), and then combine this with similar approaches targeting the most important pathways across the range of cancer hallmark phenotypes.

A comparison of plasma and prostate lycopene in response to typical servings of tomato soup, sauce or juice in men before prostatectomy

Tomato product consumption and estimated lycopene intake are hypothesised to reduce the risk of prostate cancer. To define the impact of typical servings of commercially available tomato products on resultant plasma and prostate lycopene concentrations, men scheduled to undergo prostatectomy (n 33) were randomised either to a lycopene-restricted control group ( < 5 mg lycopene/d) or to a tomato soup (2-2¾ cups prepared/d), tomato sauce (142-198 g/d or 5-7 ounces/d) or vegetable juice (325-488 ml/d or 11-16·5 fluid ounces/d) intervention providing 25-35 mg lycopene/d. Plasma and prostate carotenoid concentrations were measured by HPLC. Tomato soup, sauce and juice consumption significantly increased plasma lycopene concentration from 0·68 (sem 0·1) to 1·13 (sem 0·09) μmol/l (66 %), 0·48 (sem 0·09) to 0·82 (sem 0·12) μmol/l (71 %) and 0·49 (sem 0·12) to 0·78 (sem 0·1) μmol/l (59 %), respectively, while the controls consuming the lycopene-restricted diet showed a decline in plasma lycopene concentration from 0·55 (sem 0·60) to 0·42 (sem 0·07) μmol/l ( - 24 %). The end-of-study prostate lycopene concentration was 0·16 (sem 0·02) nmol/g in the controls, but was 3·5-, 3·6- and 2·2-fold higher in tomato soup (P= 0·001), sauce (P= 0·001) and juice (P= 0·165) consumers, respectively. Prostate lycopene concentration was moderately correlated with post-intervention plasma lycopene concentrations (r 0·60, P =0·001), indicating that additional factors have an impact on tissue concentrations. While the primary geometric lycopene isomer in tomato products was all-trans (80-90 %), plasma and prostate isomers were 47 and 80 % cis, respectively, demonstrating a shift towards cis accumulation. Consumption of typical servings of processed tomato products results in differing plasma and prostate lycopene concentrations. Factors including meal composition and genetics deserve further evaluation to determine their impacts on lycopene absorption and biodistribution.

Tomato and tomato byproducts. Human health benefits of lycopene and its application to meat products: a review

During recent decades, the food industry, consumers, and regulatory authorities have developed a significant interest in functional foods because of their potential benefits for human health over and above their basic nutritional value. Tomato is the second most important vegetable crop in the world. The amount of the related wastes is estimated at up to 50,000 tons per year, representing a serious disposal problem with a consequent negative impact on the environment. Tomato byproducts contain a great variety of biologically active substances, principally lycopene, which have been demonstrated by in vitro and in vivo studies to possess antioxidant, hypolipidemic, and anticarcinogenic activities. The aim of this review is to present an overview of the functional and physiological properties of the principal bioactive compound present in tomato and tomato byproducts, lycopene, its addition to meat, and meat products.

The potential role of lycopene for the prevention and therapy of prostate cancer: from molecular mechanisms to clinical evidence

Lycopene is a phytochemical that belongs to a group of pigments known as carotenoids. It is red, lipophilic and naturally occurring in many fruits and vegetables, with tomatoes and tomato-based products containing the highest concentrations of bioavailable lycopene. Several epidemiological studies have linked increased lycopene consumption with decreased prostate cancer risk. These findings are supported by in vitro and in vivo experiments showing that lycopene not only enhances the antioxidant response of prostate cells, but that it is even able to inhibit proliferation, induce apoptosis and decrease the metastatic capacity of prostate cancer cells. However, there is still no clearly proven clinical evidence supporting the use of lycopene in the prevention or treatment of prostate cancer, due to the only limited number of published randomized clinical trials and the varying quality of existing studies. The scope of this article is to discuss the potential impact of lycopene on prostate cancer by giving an overview about its molecular mechanisms and clinical effects.

RGD-Binding Integrins in Prostate Cancer: Expression Patterns and Therapeutic Prospects against Bone Metastasis

Prostate cancer is the third leading cause of male cancer deaths in the developed world. The current lack of highly specific detection methods and efficient therapeutic agents for advanced disease have been identified as problems requiring further research. The integrins play a vital role in the cross-talk between the cell and extracellular matrix, enhancing the growth, migration, invasion and metastasis of cancer cells. Progression and metastasis of prostate adenocarcinoma is strongly associated with changes in integrin expression, notably abnormal expression and activation of the β₃ integrins in tumour cells, which promotes haematogenous spread and tumour growth in bone. As such, influencing integrin cell expression and function using targeted therapeutics represents a potential treatment for bone metastasis, the most common and debilitating complication of advanced prostate cancer. In this review, we highlight the multiple ways in which RGD-binding integrins contribute to prostate cancer progression and metastasis, and identify the rationale for development of multi-integrin antagonists targeting the RGD-binding subfamily as molecularly targeted agents for its treatment.

Emerging putative biomarkers: the role of alpha 2 and 6 integrins in susceptibility, treatment, and prognosis

The genetic architecture underpinning prostate cancer is complex, polygenic and despite recent significant advances many questions remain. Advances in genetic technologies have greatly improved our ability to identify genetic variants associated with complex disease including prostate cancer. Genome-wide association studies (GWASs) and microarray gene expression studies have identified genetic associations with prostate cancer susceptibility and tumour development. The integrins feature prominently in both studies examining the underlying genetic susceptibility and mechanisms driving prostate tumour development. Integrins are cell adhesion molecules involved in extracellular and intracellular signalling and are imperative for tumour development, migration, and angiogenesis. Although several integrins have been implicated in tumour development, the roles of integrin α(2) and integrin α(6) are the focus of this paper as evidence is now emerging that these integrins are implicit in prostate cancer susceptibility, cancer stem cell biology, angiogenesis, cell migration, and metastases to bone and represent potential biomarkers and therapeutic targets. There currently exists an urgent need to develop tools that differentiate indolent from aggressive prostate cancers and predict how patients will respond to treatment. This paper outlines the evidence supporting the use of α(2) and α(6) integrins in clinical applications for tailored patient treatment.

Apo-10'-lycopenoic acid impacts adipose tissue biology via the retinoic acid receptors

Apo-10'-lycopenoic acid (apo-10-lycac), a metabolite of lycopene, has been shown to possess potent biological activities, notably via the retinoic acid receptors (RAR). In the current study, its impact on adipose tissue and adipocytes was studied. In microarray experiments, the set of genes regulated by apo-10-lycac treatments was compared to the set of genes regulated by all-trans retinoic acid (ATRA), the natural ligand of RAR, in adipocytes. Approximately 27.5% of the genes regulated by apo-10-lycac treatments were also regulated by ATRA, suggesting a common ability in terms of gene expression modulation, possibly via RAR transactivation. The physiological impact of apo-10-lycac on adipose tissue biology was evaluated. If it had no effect on adipogenesis in the 3T3-L1 cell model, this metabolite may have a preventative effect against inflammation, by preventing the increase in the inflammatory markers, interleukin 6 and interleukin 1β in various dedicated models. The ability of apo-10-lycac to transactivate the RAR and to modulate the transcription of RAR target gene was brought in vivo in adipose tissue. While apo-10-lycac was not detected in adipose tissue, a metabolite with a molecular weight with 2Da larger mass was detected, suggesting that a dihydro-apo-10'-lycopenoic acid, may be present in adipose tissue and that this compound could active or may lead to further active RAR-activating apo-10-lycac metabolites. Since apo-10-lycac treatments induce anti-inflammatory effects in adipose tissue but do not inhibit adipogenesis, we propose that apo-10-lycac treatments and its potential active metabolites in WAT may be considered for prevention strategies relevant for obesity-associated pathologies.

Novel α(2)β(1) integrin-targeted peptide probes for prostate cancer imaging

Accumulating experimental evidence indicates that overexpression of α(2)β(1) integrin may correlate with progression in human prostate cancer. The objective of this study was to design a novel imaging probe based on the Asp-Gly-Glu-Ala (DGEA) peptide for near-infrared-fluorescent (NIRF) imaging of α(2)β(1) integrin expression in prostate cancer. The peptides were conjugated with appropriate fluorescent dyes, and the binding affinity of these probes was evaluated by flow cytometry in three human prostate cell lines (PC-3, CWR-22, and LNCaP). In vivo NIRF imaging of the α(2)β(1)-positive PC-3 xenograft model was performed to evaluate the α(2)β(1) targeted probe. In vitro immunofluorescence staining was carried out to confirm the α(2)β(1) integrin expression level. Flow cytometry analysis showed that PC-3 had the highest probe uptake, followed by CWR-22 and LNCaP tumor cells. In the subcutaneous PC-3 model, the tumor demonstrated prominent uptake with good tumor to background contrast. Immunohistochemistry staining also supported the in vivo optical imaging results. DGEA-based optical agents have been developed for specific imaging of α(2)β(1) integrin expression. In vitro and in vivo localization demonstrated the potential of this agent to identify tumor subtypes amenable to anti-α(2)β(1) integrin treatment and potentially provide prognostic information regarding tumor progression.

Antioxidant, antiproliferative, and pro-apoptotic capacities of pentacyclic triterpenes found in the skin of olives on MCF-7 human breast cancer cells and their effects on DNA damage

This research aimed to investigate erythrodiol, uvaol, oleanolic acid, and maslinic acid scavenging capacities and their effects on cytotoxicity, cell proliferation, cell cycle, apoptosis, reactive oxygen species (ROS) level, and oxidative DNA damage on human MCF-7 breast cancer cell line. The results showed that erythrodiol, uvaol, and oleanolic acid have a significant cytotoxic effect and inhibit proliferation in a dose- and time-dependent manner. At 100 μM, erythrodiol growth inhibition occurred through apoptosis, with the observation of important ROS production and DNA damage, whereas uvaol and oleanolic acid growth inhibition involved cell cycle arrest. Moreover, although all tested triterpenes did not show free radical scavenging activity using ABTS and DPPH assays, they protected against oxidative DNA damage at the concentration 10 μM. Uvaol and oleanolic and maslinic acids, tested at 10 and 100 μM, also reduced intracellular ROS level and prevented H(2)O(2)-induced oxidative injury. Overall, the results suggest that tested triterpenes may have the potential to provide significant natural defense against human breast cancer.

Novel targets for prostate cancer chemoprevention

Among many endocrine-related cancers, prostate cancer (PCa) is the most frequent male malignancy, and it is the second most common cause of cancer-related death in men in the United States. Therefore, this review focuses on summarizing the knowledge of molecular signaling pathways in PCa because, in order to better design new preventive strategies for the fight against PCa, documentation of the knowledge on the pathogenesis of PCa at the molecular level is very important. Cancer cells are known to have alterations in multiple cellular signaling pathways; indeed, the development and the progression of PCa are known to be caused by the deregulation of several selective signaling pathways such as the androgen receptor, Akt, nuclear factor-kappaB, Wnt, Hedgehog, and Notch. Therefore, strategies targeting these important pathways and their upstream and downstream signaling could be promising for the prevention of PCa progression. In this review, we summarize the current knowledge regarding the alterations in cell signaling pathways during the development and progression of PCa, and document compelling evidence showing that these are the targets of several natural agents against PCa progression and its metastases.

Squalene protects against oxidative DNA damage in MCF10A human mammary epithelial cells but not in MCF7 and MDA-MB-231 human breast cancer cells

Until now, very little has been known about the antioxidant capacity of squalene and its effect on human breast tumourigenesis. In the present work, we investigated squalene's scavenging properties and its effect on cell proliferation, cell cycle profile, apoptosis, reactive oxygen species (ROS) level and oxidative DNA damage, using human breast cell lines. Our results showed that squalene neither possesses scavenging activity nor significantly alters cell proliferation rates, the cell cycle profile or cell apoptosis in human mammary epithelial cells (MCF10A), minimally invasive (MDA-MB-231) breast cancer cells, and highly invasive (MCF7) breast cancer cells. However, we found that squalene did exert the following effects on MCF10A epithelial cells in a dose-dependent manner: (a) it decreased intracellular ROS level, (b) it prevented H(2)O(2)-induced oxidative injury, and (c) it protected against oxidative DNA damage. Interestingly, squalene did not exert these effects on MCF7 and MDA-MB-231 cancer cells. Therefore, our data suggest that squalene, found in high amounts in virgin olive oils, could be partially responsible for the lower incidence of breast cancer in populations that consume the Mediterranean diet due to its protective activity against oxidative DNA damage in normal mammary cells.

Muscle atrophy in cancer: a role for nutrition and exercise

Developing successful antineoplastic therapies has been a primary focus of cancer research, whereas less attention has been directed at body composition and metabolism in cancer patients. Here, we examine the metabolic implications of muscle atrophy in cancer as well as the potential factors that contribute to muscle atrophy, including energy imbalance, hormone perturbations, and inflammation. The role of nutrition and exercise interventions in maintaining muscle mass during the cancer trajectory is examined.