Role of diet in prostate cancer: the epigenetic link

Variable effects of periprostatic adipose tissue on prostate cancer cells: Role of adipose tissue lipid composition and cancer cells related factors

BACKGROUND

Periprostatic adipose tissue (PPAT) is likely to modulate prostate cancer (PCa) progression. We analyzed the variations in the effect of PPAT on cancer cells, according to its fatty acid (FA) composition and tumor characteristics.

METHODS

The expression of markers of aggressiveness Ki67 and Zeb1, and epigenetic marks that could be modified during PCa progression, was analyzed by immunohistochemistry on a tissue-micro-array containing 59 pT3 PCa, including intra-prostatic areas and extra-prostatic foci in contact with PPAT belonging to the same tumor. In addition, we cocultivated PC3 and LNCaP cell lines with PPAT, which were then analyzed for FA composition.

RESULTS

Although the contact between PPAT and cancer cells led overall to an increase in Ki67 and Zeb1, and a decrease in the epigenetic marks 5MC, 5HMC, and H3K27ac, these effects were highly heterogeneous. Increased proliferation in extra-prostatic areas was associated with the international society of uropathology score. PC3 and LNCaP cocultures with PPAT led to increased Ki67, Zeb1 and H3K27me3, but only for PPAT associated with aggressive PCa. PC3 proliferation was correlated with high 20.2 n-6 and low 20.5n-3 in PPAT.

CONCLUSIONS

These results suggest that the effects of PPAT on cancer cells may depend on both PCa characteristics and PPAT composition, and could lead to propose nutritional supplementation.

Lipid Metabolism and Epigenetics Crosstalk in Prostate Cancer

Prostate cancer (PCa) is the most commonly diagnosed malignant neoplasm in men in the Western world. Localized low-risk PCa has an excellent prognosis thanks to effective local treatments; however, despite the incorporation of new therapeutic strategies, metastatic PCa remains incurable mainly due to disease heterogeneity and the development of resistance to therapy. The mechanisms underlying PCa progression and therapy resistance are multiple and include metabolic reprogramming, especially in relation to lipid metabolism, as well as epigenetic remodelling, both of which enable cancer cells to adapt to dynamic changes in the tumour. Interestingly, metabolism and epigenetics are interconnected. Metabolism can regulate epigenetics through the direct influence of metabolites on epigenetic processes, while epigenetics can control metabolism by directly or indirectly regulating the expression of metabolic genes. Moreover, epidemiological studies suggest an association between a high-fat diet, which can alter the availability of metabolites, and PCa progression. Here, we review the alterations of lipid metabolism and epigenetics in PCa, before focusing on the mechanisms that connect them. We also discuss the influence of diet in this scenario. This information may help to identify prognostic and predictive biomarkers as well as targetable vulnerabilities.

Induction of apoptosis in human hormone-refractory prostate cancer cell lines by using resveratrol in combination with AT-101

The aim of this study was to determine the appropriate doses of AT-101 and resveratrol combination in the in vitro hormone-refractory prostate cancer (PC) cell lines, in order to evaluate the cytotoxic and genotoxic effects of this combination on the proliferation of cancer cells, namely PC-3, DU-145 and LNCAP. Cytotoxicity in PC cell lines was analysed by using the XTT Cell Proliferation Assay. DNA damage was performed with the cell death assay. Apoptotic protein levels were performed by Roche Human Apoptosis Array. IC50 values were determined by XTT analysis. The strongest combined doses (100 µM resveratrol + 5µM AT-101) were found to have the strongest synergistic apoptotic and cytotoxic effects on DU-145 cells at 72 hr. While the combined use of resveratrol and AT-101 increased the expression of markers in apoptotic cell pathways on cells, a decrease in the expression of anti-apoptotic markers was detected (p ˂ 0.05). Combined applications of these compounds showed an important synergism in the hormone-refractory PC cell lines, and it was determined that after the post-translational modification, they were significantly effective on the apoptotic pathway. These results have revealed that the combination of resveratrol and AT-101 holds great expectation as a new chemotherapeutic application in the treatment of human prostate cancer.

Oxidative stress and redox signaling in CRPC progression: therapeutic potential of clinically-tested Nrf2-activators

Androgen deprivation therapy (ADT) is the mainstay regimen in patients with androgen-dependent prostate cancer (PCa). However, the selection of androgen-independent cancer cells leads to castrate resistant prostate cancer (CRPC). The aggressive phenotype of CRPC cells underscores the need to elucidate mechanisms and therapeutic strategies to suppress CRPC outgrowth. Despite ADT, the activation of androgen receptor (AR) transcription factor continues via crosstalk with parallel signaling pathways. Understanding of how these signaling cascades are initiated and amplified post-ADT is lacking. Hormone deprivation can increase oxidative stress and the resultant reactive oxygen species (ROS) may activate both AR and non-AR signaling. Moreover, ROS-induced inflammatory cytokines may further amplify these redox signaling pathways to augment AR function. However, clinical trials using ROS quenching small molecule antioxidants have not suppressed CRPC progression, suggesting that more potent and persistent suppression of redox signaling in CRPC cells will be needed. The transcription factor Nrf2 increases the expression of numerous antioxidant enzymes and downregulates the function of inflammatory transcription factors, e.g., nuclear factor kappa B. We documented that Nrf2 overexpression can suppress AR-mediated transcription in CRPC cell lines. Furthermore, two Nrf2 activating agents, sulforaphane (a phytochemical) and bardoxolone-methyl (a drug in clinical trial) suppress AR levels and sensitize CRPC cells to anti-androgens. These observations implicate the benefits of potent Nrf2-activators to suppress the lethal signaling cascades that lead to CRPC outgrowth. This review article will address the redox signaling networks that augment AR signaling during PCa progression to CRPC, and the possible utility of Nrf2-activating agents as an adjunct to ADT.

A Pilot Study on the Whole Exome Sequencing of Prostate Cancer in the Indian Phenotype Reveals Distinct Polymorphisms

Prostate cancer (PCa) is the third most common cancer among men in India, and no next-generation sequencing (NGS) studies have been attempted earlier. Recent advances in NGS have heralded the discovery of biomarkers from Caucasian/European and Chinese ancestry, but not much is known about the Indian phenotype/variant of PCa. In a pilot study using the whole exome sequencing of benign/PCa patients, we identified characteristic mutations specific to the Indian sub-population. We observed a large number of mutations in DNA repair genes, viz. helicases, TP53, and BRCA besides the variants of unknown significance with a possibly damaging rare variant (rs730881069/chr19:55154172C/TR136Q) in the TNNI3 gene that has been previously reported as a semi-conservative amino acid substitution. Our pilot study attempts to bring an understanding of PCa prognosis and recurrence for the Indian phenotype.

The overexpression of miRNA-212-5p inhibited the malignant proliferation of liver cancer cells HepG2 and the tumor formation in nude mice with transplanted tumor through down-regulating SOCS5

BACKGROUND

This study aims to investigate the effect of miR-212-5p overexpression targeting suppressor of cytokine signaling 5 (SOCS5) on the malignant proliferation of liver cancer cells HepG2 and tumor formation in nude mice with transplanted tumors.

METHODS

Luciferase reporter assay was used to detect the targeted relationship between miR-212-5p and SOCS5, and SOCS5 was overexpressed by the SOCS5 pcDNA vector. MiR-212-5p mimic and pc DNA-SOCS5 were transfected into liver cancer HepG2 cells alone or in combination, and the cells were randomly divided into four groups, the control group, mimic group, SOCS5 group and mimic + SOCS5 group for subsequent experiments. The orthotopic xenograft mouse models were established by using HepG2 cells in BALB/c athymic nude mice.

RESULTS

The results showed that there was a direct targeting relationship between miR-212-5p and SOCS5. Compared with the control group, the clone formation rate, the levels of Ki67, and proliferating cell nuclear antigen (PCNA) protein in the mimic group were significantly lower (P<0.05), but the apoptosis rate was significantly higher (P<0.05). The ratio of Bax/Bcl-2, cleaved Caspase-3/Caspase-3, and cleaved Caspase-9/Caspase-9 was significantly higher (P<0.05), while the ratios of p-phosphatidylinositol 3 kinase (PI3K)/PI3K, p- Protein kinase B (AKT)/AKT, and p-mammalian target of rapamycin (mTOR)/mTOR were significantly reduced (P<0.05). In the SOCS5 group, the result was reversed. Interesting, In the mimic+SOCS5 group the clone formation rate, the protein levels of Ki67, and PCNA were significantly decreased (P<0.05) while the apoptosis rate was significantly increased (P<0.05). The ratio of Bax/Bcl-2, cleaved Caspase-3/Caspase-3, and cleaved Caspase-9/Caspase-9 was significantly increased (P<0.05). The ratios of p-PI3K/PI3K, p-Akt/AKT, and p-mTOR/mTOR were significantly reduced (P<0.05). In vivo, The level of miR-212-5p was significantly increased, with SOCS5 decreased (P<0.05). Furthermore, the number of Ki67 positive cells was significantly reduced (P<0.05), and the apoptosis rate increased significantly (P<0.05). Additionally, the ratio of p-PI3K/PI3K, P-AKT/AKT, P-mTOR/mTOR decreased significantly (P<0.05).

CONCLUSIONS

miR-212-5p overexpression down-regulated SOCS5 could inhibit the malignant proliferation of HCC cells HepG2 and tumor formation in nude mice with transplanted tumors.

A Randomized Controlled Trial of a 6-Month Low-Carbohydrate Intervention on Disease Progression in Men with Recurrent Prostate Cancer: Carbohydrate and Prostate Study 2 (CAPS2)

PURPOSE

Both weight loss and low-carbohydrate diets (LCD) without weight loss prolong survival in prostate cancer models. Few human trials have tested weight loss or LCD on prostate cancer.

EXPERIMENTAL DESIGN

We conducted a multi-site randomized 6-month trial of LCD versus control on PSA doubling time (PSADT) in patients with prostate cancer with biochemical recurrence (BCR) after local treatment. Eligibility included body mass index (BMI) ≥ 24 kg/m² and PSADT 3 to 36 months. The LCD arm was instructed to eat [Formula: see text]20 g/carbs/day; the control arm instructed to avoid dietary changes. Primary outcome was PSADT. Secondary outcomes included weight, lipids, glucose metabolism, and diet.

RESULTS

Of 60 planned patients, the study stopped early after an interim analysis showed futility. Twenty-seven LCD and 18 control patients completed the study. At 6 months, although both arms consumed similar protein and fats, the LCD arm reduced carbohydrates intake (-117 vs. 8 g, P < 0.001) and lost weight (-12.1 vs. -0.50 kg, P < 0.001). The LCD arm reduced HDL, triglycerides, and HbA1c with no difference in total cholesterol or glucose. Mean PSADT was similar between LCD (21 months) and control (15 months, P = 0.316) arms. In a post hoc exploratory analysis accounting for prestudy PSADT, baseline PSA, primary treatment, and hemoconcentration, PSADT was significantly longer in LCD versus control (28 vs. 13 months, P = 0.021) arms. Adverse events were few, usually mild, and returned to baseline by 6 months.

CONCLUSIONS

Among BCR patients, LCD induced weight loss and metabolic benefits with acceptable safety without affecting PSADT, suggesting LCD does not adversely affect prostate cancer growth and is safe. Given exploratory findings of longer PSADT, larger studies testing LCD on disease progression are warranted.

Dietary fatty acid quality affects systemic parameters and promotes prostatitis and pre-neoplastic lesions

Environmental and nutritional factors, including fatty acids (FA), are associated with prostatitis, benign prostate hyperplasia and prostate cancer. We hypothesized that different FA in normolipidic diets (7%) affect prostate physiology, increasing the susceptibility to prostate disorders. Thus, we fed male C57/BL6 mice with normolipidic diets based on linseed oil, soybean oil or lard (varying saturated and unsaturated FA contents and ω-3/ω-6 ratios) for 12 or 32 weeks after weaning and examined structural and functional parameters of the ventral prostate (VP) in the systemic metabolic context. Mongolian gerbils were included because they present a metabolic detour for low water consumption (i.e., oxidize FA to produce metabolic water). A linseed oil-based diet (LO, 67.4% PUFAs, ω-3/ω-6 = 3.70) resulted in a thermogenic profile, while a soybean oil-based diet (SO, 52.7% PUFAs, ω-3/ω-6 = 0.11) increased body growth and adiposity. Mice fed lard (PF, 13.1% PUFA, ω-3/ω-6 = 0.07) depicted a biphasic growth, resulting in decreased adiposity in adulthood. SO and PF resulted in hepatic steatosis and steatohepatitis, respectively. PF and SO increased prostate epithelial volume, and lard resulted in epithelial hyperplasia. Animals in the LO group had smaller prostates with predominant atrophic epithelia and inflammatory loci. Inflammatory cells were frequent in the VP of PF mice (predominantly stromal) and LO mice (predominantly luminal). RNAseq after 12 weeks revealed good predictors of a later-onset inflammation. The transcriptome unveiled ontologies related to ER stress after 32 weeks on PF diets. In conclusion, different FA qualities result in different metabolic phenotypes and differentially impact prostate size, epithelial volume, inflammation and gene expression.

Dietary inflammatory index and the risk of prostate cancer: a dose-response meta-analysis

Emerging epidemiological studies have assessed the potential relationship between the inflammatory potential of diet measured using the dietary inflammatory index (DII) and the risk of prostate cancer and found inconsistent results. The aim of this study was to systematically evaluate this issue using a meta-analysis approach. A comprehensive literature search of papers published through March 2019 was performed in the PubMed and EMBASE databases. The summary odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using a DerSimonian and Laird random effects model. A categorized analysis and linear and nonlinear dose-response analyses were performed. Ten studies met the inclusion criteria for our meta-analysis. The highest DII score category was associated with a significantly higher risk of prostate cancer than the lowest DII score category (OR = 1.73, 95% CI 1.34-2.23). In the dose-response analysis, the summary OR of prostate cancer for an increment of one unit of the DII was 1.10 (95% CI 1.04-1.17). The sensitivity analysis indicated that exclusion of any single study did not materially alter the pooled risk estimates. Finally, there was no evidence of significant publication bias with Begg's test or with Egger's test. In conclusion, this meta-analysis suggests that an increased DII is related to a higher risk of prostate cancer and that the risk increases by 10.0% per unit of the DII. However, further well-designed prospective trials with larger sample sizes should be performed to validate our preliminary findings.

High-fat diet fuels prostate cancer progression by rewiring the metabolome and amplifying the MYC program

Systemic metabolic alterations associated with increased consumption of saturated fat and obesity are linked with increased risk of prostate cancer progression and mortality, but the molecular underpinnings of this association are poorly understood. Here, we demonstrate in a murine prostate cancer model, that high-fat diet (HFD) enhances the MYC transcriptional program through metabolic alterations that favour histone H4K20 hypomethylation at the promoter regions of MYC regulated genes, leading to increased cellular proliferation and tumour burden. Saturated fat intake (SFI) is also associated with an enhanced MYC transcriptional signature in prostate cancer patients. The SFI-induced MYC signature independently predicts prostate cancer progression and death. Finally, switching from a high-fat to a low-fat diet, attenuates the MYC transcriptional program in mice. Our findings suggest that in primary prostate cancer, dietary SFI contributes to tumour progression by mimicking MYC over expression, setting the stage for therapeutic approaches involving changes to the diet.

Sweet Cherry Extract Targets the Hallmarks of Cancer in Prostate Cells: Diminished Viability, Increased Apoptosis and Suppressed Glycolytic Metabolism

The present work evaluated the anticancer properties of sweet cherry (Prunus avium) extract on human prostate cells. Several sweet cherry cultivars from Fundão (Portugal) were methanol-extracted and their phytochemical composition characterized. The Saco "late harvest" extract was highly-enriched in anthocyanins and selected for use in biological assays. Non-neoplastic (PNT1A) and neoplastic (LNCaP and PC3) human prostate cells were treated with 0-2,000 μg/ml of extract for 48-96 h. Cell viability was evaluated by the MTT assay. Apoptosis, oxidative stress, and glycolytic metabolism were assessed by Western blotting and enzymatic assays. Glucose consumption and lactate production were measured spectrophotometrically. Saco cherry extract diminished the viability of neoplastic and non-neoplastic cells, whereas enhancing apoptosis in LNCaP. Cherry extract-treatment also diminished oxidative damage and suppressed glycolytic metabolism in LNCaP cells. These findings widened the knowledge on the mechanisms by which cherry extract modulate cell physiology, demonstrating their broad action over the hallmarks of cancer.

Dietary palmitate cooperates with Src kinase to promote prostate tumor progression

Numerous genetic alterations have been identified during prostate cancer progression. The influence of environmental factors, particularly the diet, on the acceleration of tumor progression is largely unknown. Expression levels and/or activity of Src kinase are highly elevated in numerous cancers including advanced stages of prostate cancer. In this study, we demonstrate that high-fat diets (HFDs) promoted pathological transformation mediated by the synergy of Src and androgen receptor in vivo. Additionally, a diet high in saturated fat significantly enhanced proliferation of Src-mediated xenograft tumors in comparison with a diet high in unsaturated fat. The saturated fatty acid palmitate, a major constituent in a HFD, significantly upregulated the biosynthesis of palmitoyl-CoA in cancer cells in vitro and in xenograft tumors in vivo. The exogenous palmitate enhanced Src-dependent mitochondrial β-oxidation. Additionally, it elevated the amount of C16-ceramide and total saturated ceramides, increased the level of Src kinase localized in the cell membrane, and Src-mediated downstream signaling, such as the activation of mitogen-activated protein kinase and focal adhesion kinase. Our results uncover how the metabolism of dietary palmitate cooperates with elevated Src kinase in the acceleration of prostate tumor progression.

Metabolic Vulnerabilities of Prostate Cancer: Diagnostic and Therapeutic Opportunities

Cancer cells hijack metabolic pathways to support bioenergetics and biosynthetic requirements for their uncontrolled growth. Thus, cancer can be considered as a metabolic disease. In this review, we discuss the main metabolic features of prostate cancer with a particular focus on the link between oncogene-directed cancer metabolic regulation, metabolism rewiring, and epigenetic regulation. The potential of using metabolic profiling as a means to predict disease behavior and to identify novel therapeutic targets and new diagnostic markers will be addressed as well as the current challenges in metabolomics analyses. Finally, diagnostic and prognostic metabolic imaging approaches, including positron emission tomography, mass spectrometry, nuclear magnetic resonance, and their translational applications, will be discussed. Here, we emphasize how targeting metabolic vulnerabilities in prostate cancer may pave the way for novel personalized diagnostic and therapeutic interventions.

Increased inflammatory potential of diet is associated with increased odds of prostate cancer in Argentinian men

PURPOSE

Various aspects of diet, including specific food items and nutrients, have been shown to modulate inflammation and have been implicated in the etiology of prostate cancer (PrCA). No study examining the role of diet-associated inflammation in PrCA has been conducted in Latin America.

METHOD

We examined the association between the Dietary Inflammatory Index (DII®) and PrCA in a population-based case-control study in Córdoba, Argentina. A total of 153 incident cases of PrCA and 309 controls frequency matched on sex, age (± 5 years), and place of residence were recruited from 2008 to 2015. The DII was developed to determine the inflammatory potential of individuals' diets and was computed from a validated food frequency questionnaire using nutrient data from diet only. Multi-level logistic regression models were fit to evaluate the association between DII scores and PrCA, adjusting for age, body mass index, energy intake, and occupational exposure as first-level covariates and family history of prostate cancer as the second-level variable. Odds ratios were estimated in all subject and stratified by BMI (< 30 vs. ≥ 30 kg/m2).

RESULTS

Men in the most pro-inflammatory group (tertile 3) had 50% higher odds of having PrCA compared to men in the most anti-inflammatory group (tertile 1) (ORtertile3 vs. tertile1 1.50; 95% CI 1.24-1.80). The odds of prostate cancer were higher in obese men (n = 109, ORtertile3 vs. tertile1 1.81; 95% CI 1.45-2.27), while no association was found among non-obese men (n = 375, ORtertile3 vs. tertile1 0.93; 95% CI 0.25-3.51).

CONCLUSIONS

A pro-inflammatory diet, reflected by higher DII scores, was positively associated with PrCA occurrence. Based on these results and those from other studies, steps should be taken to promote a diet rich in anti-inflammatory foods, in order to reduce risk of PrCA and other chronic diseases. Future studies should explore this association in a prospective setting.

Recent advances in prostate cancer research: large-scale genomic analyses reveal novel driver mutations and DNA repair defects

Prostate cancer (PCa) is a disease of mutated and misregulated genes. However, primary prostate tumors have relatively few mutations, and only three genes ( ERG, PTEN, and SPOP) are recurrently mutated in more than 10% of primary tumors. On the other hand, metastatic castration-resistant tumors have more mutations, but, with the exception of the androgen receptor gene ( AR), no single gene is altered in more than half of tumors. Structural genomic rearrangements are common, including ERG fusions, copy gains involving the MYC locus, and copy losses containing PTEN. Overall, instead of being associated with a single dominant driver event, prostate tumors display various combinations of modifications in oncogenes and tumor suppressors. This review takes a broad look at the recent advances in PCa research, including understanding the genetic alterations that drive the disease and how specific mutations can sensitize tumors to potential therapies. We begin with an overview of the genomic landscape of primary and metastatic PCa, enabled by recent large-scale sequencing efforts. Advances in three-dimensional cell culture techniques and mouse models for PCa are also discussed, and particular emphasis is placed on the benefits of patient-derived xenograft models. We also review research into understanding how ETS fusions (in particular, TMPRSS2-ERG) and SPOP mutations contribute to tumor initiation. Next, we examine the recent findings on the prevalence of germline DNA repair mutations in about 12% of patients with metastatic disease and their potential benefit from the use of poly(ADP-ribose) polymerase (PARP) inhibitors and immune modulation. Lastly, we discuss the recent increased prevalence of AR-negative tumors (neuroendocrine and double-negative) and the current state of immunotherapy in PCa. AR remains the primary clinical target for PCa therapies; however, it does not act alone, and better understanding of supporting mutations may help guide the development of novel therapeutic strategies.

PPARGC1A and ADIPOQ polymorphisms are associated with aggressive prostate cancer in Mexican-Mestizo men with overweight or obesity

BACKGROUND

Obesity constitutes a risk factor for the development of aggressive forms of prostate cancer. It has been proposed, that prostate cancer has a genetic predisposition and that PPARGC1A and ADIPOQ polymorphisms play a role in the development of this condition.

OBJECTIVE

To analyse the association of two PPARGC1A and ADIPOQ polymorphisms as well as their haplotypes, with the development of aggressive prostate cancer in Mexican-Mestizo men with overweight or obesity.

SUBJECTS AND METHODS

Two hundred fifty seven men with prostate cancer of Mexican-Mestizo origin were included. Body mass index (BMI) was determined and the degree of prostate cancer aggressiveness by the D'Amico classification. DNA was obtained. Rs7665116 and rs2970870 of PPARGC1A, and rs266729 and rs1501299 of ADIPOQ were studied by real-time PCR allelic discrimination. Pairwise linkage disequilibrium, between single nucleotide polymorphisms was calculated and haplotype analysis was performed.

RESULTS

A higher-risk (D'Amico classification) was observed in 21.8% of patients. An association of cancer aggressiveness with rs2970870 of PPARGC1A, and rs501299 of ADIPOQ, as well as with one haplotype of ADIPOQ was documented.

CONCLUSIONS

This is the first study regarding the relationship of PPARGC1A and ADIPOQ polymorphisms, and the aggressiveness of prostate cancer in men with overweight or obesity.

Epigenome-wide DNA methylation profiling of periprostatic adipose tissue in prostate cancer patients with excess adiposity-a pilot study

Background

Periprostatic adipose tissue (PPAT) has been recognized to associate with prostate cancer (PCa) aggressiveness and progression. Here, we sought to investigate whether excess adiposity modulates the methylome of PPAT in PCa patients. DNA methylation profiling was performed in PPAT from obese/overweight (OB/OW, BMI > 25 kg m⁻²) and normal weight (NW, BMI < 25 kg m⁻²) PCa patients. Significant differences in methylated CpGs between OB/OW and NW groups were inferred by statistical modeling.

Results

Five thousand five hundred twenty-six differentially methylated CpGs were identified between OB/OW and NW PCa patients with 90.2% hypermethylated. Four hundred eighty-three of these CpGs were found to be located at both promoters and CpG islands, whereas the representing 412 genes were found to be involved in pluripotency of stem cells, fatty acid metabolism, and many other biological processes; 14 of these genes, particularly FADS1, MOGAT1, and PCYT2, with promoter hypermethylation presented with significantly decreased gene expression in matched samples. Additionally, 38 genes were correlated with antigen processing and presentation of endogenous antigen via MHC class I, which might result in fatty acid accumulation in PPAT and tumor immune evasion.

Conclusions

Results showed that the whole epigenome methylation profiles of PPAT were significantly different in OB/OW compared to normal weight PCa patients. The epigenetic variation associated with excess adiposity likely resulted in altered lipid metabolism and immune dysregulation, contributing towards unfavorable PCa microenvironment, thus warranting further validation studies in larger samples.

Electronic supplementary material

The online version of this article (10.1186/s13148-018-0490-3) contains supplementary material, which is available to authorized users.

The influence of nutritional factors on prostate cancer incidence and aggressiveness

There is an increasing evidence for a link between nutrition, lifestyle and prostate cancer (PCa) development and/or progression of disease. The objective of this study was to examine the association between dietary factors and PCa incidence and aggressiveness in a case-control study. After the analysis of the anatomic pathology, subjects were classified in patients with PCa (n = 157) and controls (n = 158). Clinical data including Gleason score, PSA values and biopsy results, were compiled. Frequencies of food consumption and sociodemographic data were also obtained. The results showed that physical activity was significantly higher in control (p < .022). It was also found that some nutritional habits offer a protective effect among studied subjects, like high nuts (p = .041) and fish (p = .041) intakes. Moreover, there was a significant reduction in risk (p = .029) in cases with a higher fruits and vegetables intakes. A decreased risk of aggressive PCa was associated with fruits, vegetables, legumes and fish intakes. However, these relationships were not statistically significant when data were adjusted for covariates. In conclusion, this study found an inverse association between PCa risk and the intake of fruits and vegetables, fish and nuts. The results suggested that a diet with higher intakes of these foods as Mediterranean diet may lower the risk of PCa in the studied population. As dietary factors are modifiable, identifying food groups or dietary patterns that modulate the risk of PCa and its aggressiveness can offer effective and practical strategies for its primary prevention.

Cnidium officinale Makino extract induces apoptosis through activation of caspase-3 and p53 in human liver cancer HepG2 cells

A number of diverse studies have reported the anticancer properties of Cnidium officinale Makino (CO). However, the apoptotic effect of this traditional medicinal herb in human hepatocellular carcinoma cells (HepG2) remains to be elucidated. Therefore, the present study investigated the ability of CO to reduce cell viability through apoptotic pathways. Cell viability was determined using the 2,3-bis [2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide assay. CO extract-induced apoptosis in HepG2 cells was assessed by Hoechst 33258 staining. The cell cycle was monitored using fluorescence-activated cell sorting analysis with propidium iodide staining. Furthermore, the present study explored whether various signaling molecules associated with HepG2 cell death were affected by CO treatment, including caspase-3, B-cell lymphoma 2 (Bcl-2), tumor protein p53 (p53), cyclin-dependent kinase 4 (CDK4) and cyclin D. The expression levels of these genes were examined by reverse-transcription polymerase chain reaction and western blotting. The expression levels of caspase-3 and p53 were upregulated with CO extract treatment, whereas those of Bcl-2, CDK4 and cyclin D were significantly downregulated. Cleaved caspase-3 expression was upregulated following treatment with CO extract in a dose-dependent manner. Collectively, the data suggest that CO extract has the potential to induce apoptosis of HepG2 cells and may act by suppressing the cell cycle, which leads to caspase-3 cleavage and p53 signaling.

Association Between a Dietary Inflammatory Index and Prostate Cancer Risk in Ontario, Canada

BACKGROUND

Evidence exists showing that various aspects of diet are implicated in the etiology of prostate cancer, although results across studies remain inconsistent.

METHODS

We examined the ability of the dietary inflammatory index (DII) to predict prostate cancer in a case-control study conducted in Kingston, Ontario, Canada, between 1997 and 1999. The study included 72 cases of incident primary prostate cancer patients and 302 controls of urology clinic patients who had prostate conditions other than prostate cancer. The DII was computed based on intake of 18 nutrients assessed using a 67-item food frequency questionnaire. Univariate and multivariate logistic regression models were used to estimate odds ratios (ORs).

RESULTS

Men with higher DII scores were at increased risk of prostate cancer using DII score fit both as a continuous [OR = 1.58, 95% confidence interval (CI) 1.05-2.38] and categorical variable [compared to men in the lowest DII quartile, men in the highest quartile were at elevated risk (OR = 3.50, 95% CI 1.25-9.80; ptrend = 0.02)]. There was no significant heterogeneity by weight status, but stronger association was observed in men with body mass index >25 kg/m2 versus <25 kg/m2.

CONCLUSION

These findings suggest that a proinflammatory diet, as indicated by increasing DII score, is a risk factor for prostate cancer.

Gene expression profiling of prostate tissue identifies chromatin regulation as a potential link between obesity and lethal prostate cancer

BACKGROUND

Obese men are at higher risk of advanced prostate cancer and cancer-specific mortality; however, the biology underlying this association remains unclear. This study examined gene expression profiles of prostate tissue to identify biological processes differentially expressed by obesity status and lethal prostate cancer.

METHODS

Gene expression profiling was performed on tumor (n = 402) and adjacent normal (n = 200) prostate tissue from participants in 2 prospective cohorts who had been diagnosed with prostate cancer from 1982 to 2005. Body mass index (BMI) was calculated from the questionnaire immediately preceding cancer diagnosis. Men were followed for metastases or prostate cancer-specific death (lethal disease) through 2011. Gene Ontology biological processes differentially expressed by BMI were identified using gene set enrichment analysis. Pathway scores were computed by averaging the signal intensities of member genes. Odds ratios (ORs) for lethal prostate cancer were estimated with logistic regression.

RESULTS

Among 402 men, 48% were healthy weight, 31% were overweight, and 21% were very overweight/obese. Fifteen gene sets were enriched in tumor tissue, but not normal tissue, of very overweight/obese men versus healthy-weight men; 5 of these were related to chromatin modification and remodeling (false-discovery rate < 0.25). Patients with high tumor expression of chromatin-related genes had worse clinical characteristics (Gleason grade > 7, 41% vs 17%; P = 2 × 10^-4 ) and an increased risk of lethal disease that was independent of grade and stage (OR, 5.26; 95% confidence interval, 2.37-12.25).

CONCLUSIONS

This study improves our understanding of the biology of aggressive prostate cancer and identifies a potential mechanistic link between obesity and prostate cancer death that warrants further study. Cancer 2017;123:4130-4138. © 2017 American Cancer Society.

Levels of plasma selenium and urinary total arsenic interact to affect the risk for prostate cancer

This study investigated whether plasma selenium levels modified the risk for prostate cancer (PC) related to arsenic exposure. We conducted a case-control study that included 318 PC patients and 318 age-matched, healthy control subjects. Urinary arsenic profiles were examined using HPLC-HG-AAS and plasma selenium levels were measured by ICP-MS. We found that plasma selenium levels displayed a significant dose-dependent inverse association with PC. The odds ratio (OR) and 95% confidence interval (CI) for PC was 0.07 (0.04-0.13) among participants with a plasma selenium level >28.06 μg/dL vs. ≤19.13 μg/dL. A multivariate analysis showed that participants with a urinary total arsenic concentration >29.28 μg/L had a significantly higher OR (1.75, 1.06-2.89) for PC than participants with ≤29.89 μg/L. The combined presence of a low plasma selenium level and a high urinary total arsenic concentration exponentially increased the OR for PC, and additively interacted with PSA at levels ≥20 ng/mL. This is the first epidemiological study to examine the combined effects of plasma selenium and urinary total arsenic levels on the OR for PC. Our data suggest a low plasma selenium level coupled with a high urinary total arsenic concentration creates a significant risk for aggressive PC.

The Genomic Impact of DNA CpG Methylation on Gene Expression; Relationships in Prostate Cancer

The process of DNA CpG methylation has been extensively investigated for over 50 years and revealed associations between changing methylation status of CpG islands and gene expression. As a result, DNA CpG methylation is implicated in the control of gene expression in developmental and homeostasis processes, as well as being a cancer-driver mechanism. The development of genome-wide technologies and sophisticated statistical analytical approaches has ushered in an era of widespread analyses, for example in the cancer arena, of the relationships between altered DNA CpG methylation, gene expression, and tumor status. The remarkable increase in the volume of such genomic data, for example, through investigators from the Cancer Genome Atlas (TCGA), has allowed dissection of the relationships between DNA CpG methylation density and distribution, gene expression, and tumor outcome. In this manner, it is now possible to test that the genome-wide correlations are measurable between changes in DNA CpG methylation and gene expression. Perhaps surprisingly is that these associations can only be detected for hundreds, but not thousands, of genes, and the direction of the correlations are both positive and negative. This, perhaps, suggests that CpG methylation events in cancer systems can act as disease drivers but the effects are possibly more restricted than suspected. Additionally, the positive and negative correlations suggest direct and indirect events and an incomplete understanding. Within the prostate cancer TCGA cohort, we examined the relationships between expression of genes that control DNA methylation, known targets of DNA methylation and tumor status. This revealed that genes that control the synthesis of S-adenosyl-l-methionine (SAM) associate with altered expression of DNA methylation targets in a subset of aggressive tumors.

P110β Inhibition Reduces Histone H3K4 Di-Methylation in Prostate Cancer

INTRODUCTION AND AIMS

Epigenetic alteration plays a major role in the development and progression of human cancers, including prostate cancer. Histones are the key factors in modulating gene accessibility to transcription factors and post-translational modification of the histone N-terminal tail including methylation is associated with either transcriptional activation (H3K4me2) or repression (H3K9me3). Furthermore, phosphoinositide 3-kinase (PI3 K) signaling and the androgen receptor (AR) are the key determinants in prostate cancer development and progression. We recently showed that prostate-targeted nano-micelles loaded with PI3 K/p110beta specific inhibitor TGX221 blocked prostate cancer growth in vitro and in vivo. Our objective of this study was to determine the role of PI3 K signaling in histone methylation in prostate cancer, with emphasis on histone H3K4 methylation.

METHODS

PI3 K non-specific inhibitor LY294002 and p110beta-specific inhibitor TGX221 were used to block PI3 K/p110beta signaling. The global levels of H3K4 and H3K9 methylation in prostate cancer cells and tissue specimens were evaluated by Western blot assay and immunohistochemical staining. A synthetic androgen R1881 was used to stimulate AR activity in prostate cancer cells. A castration-resistant prostate cancer (CRPC) specific human tissue microarray (TMA) was used to assess the global levels of H3K4me2 methylation by immunostaining approach.

RESULTS

Our data revealed that H3K4me2 levels were significantly elevated after androgen stimulation. With RNA silencing and pharmacology approaches, we further defined that inhibition of PI3 K/p110beta activity through gene-specific knocking down and small chemical inhibitor TGX221 abolished androgen-stimulated H3K4me2 methylation. Consistently, prostate cancer-targeted delivery of TGX221 in vivo dramatically reduced the global levels of H3K4me2 as assessed by immunohistochemical staining on tissue section of mouse xenografts from CRPC cell lines 22RV1 and C4-2. Finally, immunostaining data revealed a strong H3K4me2 immunosignal in CRPC tissues compared to primary tumors and benign prostate tissues.

CONCLUSIONS

Taken together, our results suggest that PI3 K/p110beta-dependent signaling is involved in androgen-stimulated H3K4me2 methylation in prostate cancer, which might be used as a novel biomarker for disease prognosis and targeted therapy. Prostate 77:299-308, 2017. © 2016 Wiley Periodicals, Inc.

Genetic variants in ATP6 and ND3 mitochondrial genes are not associated with aggressive prostate cancer in Mexican-Mestizo men with overweight or obesity

Mitochondrial defects have been related to obesity and prostate cancer. We investigated if Mexican-Mestizo men presenting this type of cancer, exhibited somatic mutations of ATP6 and/or ND3.Body mass index (BMI) was determined; the degree of prostate cancer aggressiveness was demarcated by the Gleason score. DNA from tumor tissue and from blood leukocytes was amplified by the polymerase chain reaction and ATP6 and ND3 were sequenced. We included 77 men: 20 had normal BMI, 38 were overweight and 19 had obesity; ages ranged from 52 to 83. After sequencing ATP6 and ND3, from DNA obtained from leukocytes and tumor tissue, we did not find any somatic mutations. All changes observed, in both genes, were polymorphisms. In ATP6 we identified, in six patients, two non-synonymous nucleotide changes and in ND3 we observed that twelve patients presented non-synonymous polymorphisms. To our knowledge, this constitutes the first report where the complete sequences of the ATP6 and ND3 have been analyzed in Mexican-Mestizo men with prostate cancer and diverse BMI. Our results differ with those reported in Caucasian populations, possibly due to ethnic differences.

Gingerol Reverses the Cancer-Promoting Effect of Capsaicin by Increased TRPV1 Level in a Urethane-Induced Lung Carcinogenic Model

Both gingerol and capsaicin are agonists of TRPV1, which can negatively control tumor progression. This study observed the long-term effects of oral administration of 6-gingerol alone or in combination with capsaicin for 20 weeks in a urethane-induced lung carcinogenic model. We showed that lung carcinoma incidence and multiplicity were 70% and 21.2 ± 3.6, respectively, in the control versus 100% and 35.6 ± 5.2 in the capsaicin group (P < 0.01) and 50% and 10.8 ± 3.1 in the 6-gingerol group (P < 0.01). The combination of 6-gingerol and capsaicin reversed the cancer-promoting effect of capsaicin (carcinoma incidence of 100% versus 20% and multiplicity of 35.6 ± 5.2 versus 4.7 ± 2.3; P < 0.001). The cancer-promoting effect of capsaicin was due to increased epidermal growth-factor receptor (EGFR) level by decreased transient receptor potential vanilloid type-1 (TRPV1) level (P < 0.01) . The capsaicin-decreased EGFR level subsequently reduced levels of nuclear factor-κB (NF-κB) and cyclin D1 that favored enhanced lung epithelial proliferation and epithelial-mesenchymal transition (EMT) during lung carcinogenesis (P < 0.01). In contrast, 6-gingerol promoted TRPV1 level and drastically decreased the levels of EGFR, NF-κB, and cyclin D1 that favored reduced lung epithelial proliferation and EMT (P < 0.01). This study provides valuable information for the long-term consumption of chili-pepper-rich diets to decrease the risk of cancer development.

One-Carbon Metabolism in Prostate Cancer: The Role of Androgen Signaling

Cancer cell metabolism differs significantly from the metabolism of non-transformed cells. This altered metabolic reprogramming mediates changes in the uptake and use of nutrients that permit high rates of proliferation, growth, and survival. The androgen receptor (AR) plays an essential role in the establishment and progression of prostate cancer (PCa), and in the metabolic adaptation that takes place during this progression. In its role as a transcription factor, the AR directly affects the expression of several effectors and regulators of essential catabolic and biosynthetic pathways. Indirectly, as a modulator of the one-carbon metabolism, the AR can affect epigenetic processes, DNA metabolism, and redox balance, all of which are important factors in tumorigenesis. In this review, we focus on the role of AR-signaling on one-carbon metabolism in tumorigenesis. Clinical implications of one-carbon metabolism and AR-targeted therapies for PCa are discussed in this context.

Germline genetic profiling in prostate cancer: latest developments and potential clinical applications

Familial and twin studies have demonstrated a significant inherited component to prostate cancer predisposition. Genome wide association studies have shown that there are 100 single nucleotide polymorphisms which have been associated with the development of prostate cancer. This review aims to discuss the scientific methods used to identify these susceptibility loci. It will also examine the current clinical utility of these loci, which include the development of risk models as well as predicting treatment efficacy and toxicity. In order to refine the clinical utility of the susceptibility loci, international consortia have been developed to combine statistical power as well as skills and knowledge to further develop models that could be used to predict risk and treatment outcomes.

Fried food and prostate cancer risk: systematic review and meta-analysis

We performed systematic review and meta-analysis of published studies that investigated the potential association between fried food consumption and prostate cancer risk. Four case-control studies were finally selected for this systematic literature review, totaling 2579 cancer patients and 2277 matched controls. In two of these studies, the larger intake of fried food was associated with a 1.3- to 2.3-fold increased risk of prostate cancer, no significant association was found in another, whereas an inverse relationship was observed in the remaining. The meta-analysis of published data showed that larger intake of fried food was associated with a 35% (95% CI 17-57%) increased risk of prostate cancer. The results of this systematic literature review support the notion that larger intake of fried foods may have a role in increasing the risk of prostate cancer.