Choline intake and risk of lethal prostate cancer: incidence and survival

Transcending frontiers in prostate cancer: the role of oncometabolites on epigenetic regulation, CSCs, and tumor microenvironment to identify new therapeutic strategies

Prostate cancer, as one of the most prevalent malignancies in males, exhibits an approximate 5-year survival rate of 95% in advanced stages. A myriad of molecular events and mutations, including the accumulation of oncometabolites, underpin the genesis and progression of this cancer type. Despite growing research demonstrating the pivotal role of oncometabolites in supporting various cancers, including prostate cancer, the root causes of their accumulation, especially in the absence of enzymatic mutations, remain elusive. Consequently, identifying a tangible therapeutic target poses a formidable challenge. In this review, we aim to delve deeper into the implications of oncometabolite accumulation in prostate cancer. We center our focus on the consequential epigenetic alterations and impacts on cancer stem cells, with the ultimate goal of outlining novel therapeutic strategies.

Metabolomic epidemiology offers insights into disease aetiology

Metabolomic epidemiology is the high-throughput study of the relationship between metabolites and health-related traits. This emerging and rapidly growing field has improved our understanding of disease aetiology and contributed to advances in precision medicine. As the field continues to develop, metabolomic epidemiology could lead to the discovery of diagnostic biomarkers predictive of disease risk, aiding in earlier disease detection and better prognosis. In this Review, we discuss key advances facilitated by the field of metabolomic epidemiology for a range of conditions, including cardiometabolic diseases, cancer, Alzheimer's disease and COVID-19, with a focus on potential clinical utility. Core principles in metabolomic epidemiology, including study design, causal inference methods and multi-omic integration, are briefly discussed. Future directions required for clinical translation of metabolomic epidemiology findings are summarized, emphasizing public health implications. Further work is needed to establish which metabolites reproducibly improve clinical risk prediction in diverse populations and are causally related to disease progression.

Genomic and Phenotypic Biomarkers for Precision Medicine Guidance in Advanced Prostate Cancer

OPINION STATEMENT

Prostate cancer (PCa) is the second most diagnosed malignant neoplasm and is one of the leading causes of cancer-related death in men worldwide. Despite significant advances in screening and treatment of PCa, given the heterogeneity of this disease, optimal personalized therapeutic strategies remain limited. However, emerging predictive and prognostic biomarkers based on individual patient profiles in combination with computer-assisted diagnostics have the potential to guide precision medicine, where patients may benefit from therapeutic approaches optimally suited to their disease. Also, the integration of genotypic and phenotypic diagnostic methods is supporting better informed treatment decisions. Focusing on advanced PCa, this review discusses polygenic risk scores for screening of PCa and common genomic aberrations in androgen receptor (AR), PTEN-PI3K-AKT, and DNA damage response (DDR) pathways, considering clinical implications for diagnosis, prognosis, and treatment prediction. Furthermore, we evaluate liquid biopsy, protein biomarkers such as serum testosterone levels, SLFN11 expression, total alkaline phosphatase (tALP), neutrophil-to-lymphocyte ratio (NLR), tissue biopsy, and advanced imaging tools, summarizing current phenotypic biomarkers and envisaging more effective utilization of diagnostic and prognostic biomarkers in advanced PCa. We conclude that prognostic and treatment predictive biomarker discovery can improve the management of patients, especially in metastatic stages of advanced PCa. This will result in decreased mortality and enhanced quality of life and help design a personalized treatment regimen.

Dietary choline and sphingomyelin choline moiety intake and risk of colorectal cancer: a case-control study

INTRODUCTION

Phospholipids are possible favorable agents for colorectal cancer (CRC). Choline has been inversely related to CRC risk but findings are inconsistent. We assessed the effect of dietary sphingomyelin (SM) choline moiety and total choline intake on risk of CRC.

METHOD

This analysis is based on a multicenter case-control study conducted between 1992 and 1996 in Italy. A total of 6107 subjects were enrolled, including 1225 colon cancer cases, 728 rectal cancer cases and 4154 hospital-based controls. We applied data on the composition of foods in terms of SM choline moiety and choline intake on dietary information collected through a validated food-frequency questionnaire. Odds ratio (OR) for energy-adjusted tertiles of SM choline moiety and choline were estimated through logistic regression models adjusted for sex, age, center, education, alcohol consumption, body mass index, family history of CRC, and physical activity.

RESULTS

Choline was inversely related to CRC risk (OR for the highest versus the lowest tertile: 0.85; 95% confidence interval [CI]: 0.73-0.99), with a significant trend in risk. The OR for an increment of one standard deviation of energy-adjusted choline intake was 0.93 (95% CI: 0.88-0.98). The association was consistent in colon and rectal cancer and also across colon subsites. SM choline moiety was not associated with CRC risk (OR for the highest versus the lowest tertile: 0.96, 95% CI 0.84-1.11).

CONCLUSION

This study shows an inverse association between choline intake and CRC but not with SM choline moiety.

Association between Levels of Trimethylamine N-Oxide and Cancer: A Systematic Review and Meta-Analysis

Cancer is the second leading cause of death in the world. Reports on the effect of Trimethylamine-N-oxide (TAMO), a small amine oxide generated by gut microbial metabolism of choline, betaine, and carnitine, on cancer are inconsistent. Therefore, this systematic review and meta-analysis summarize the effect of TAMO on cancer incidence. A systematic search was conducted in PubMed, Scopus, Web of Science, and Embase. Data were pooled using the random-effects method and were expressed as weighted mean difference (WMD) and 95% confidence intervals (CI). The pooled results of 16 studies, including 5930 participants, showed that the association between TMAO levels and cancer incidence is insignificant (Odds Ratio: 0.97, 95% CI: (0.64, 1.46), P-value = 0.871). Subgroup analysis showed that urinary TMAO levels were negatively associated with cancer incidence; in contrast, a direct and positive association was observed between serum TMAO levels and cancer incidence. However, "gender" and the "TMAO measuring method" were the potential sources of discrepancies. Meta-regression analysis did not reveal any significant association between duration of studies, age, female ratio, subjects-control, and subjects-case. The present study demonstrates that serum TAMO levels were insignificantly associated with cancer incidence.

Contribution of Trimethylamine N-Oxide (TMAO) to Chronic Inflammatory and Degenerative Diseases

Trimethylamine N-oxide (TMAO) is a metabolite produced by the gut microbiota and has been mainly associated with an increased incidence of cardiovascular diseases (CVDs) in humans. There are factors that affect one's TMAO level, such as diet, drugs, age, and hormones, among others. Gut dysbiosis in the host has been studied recently as a new approach to understanding chronic inflammatory and degenerative diseases, including cardiovascular diseases, metabolic diseases, and Alzheimer's disease. These disease types as well as COVID-19 are known to modulate host immunity. Diabetic and obese patients have been observed to have an increase in their level of TMAO, which has a direct correlation with CVDs. This metabolite is attributed to enhancing the inflammatory pathways through cholesterol and bile acid dysregulation, promoting foam cell formation. Additionally, TMAO activates the transcription factor NF-κB, which, in turn, triggers cytokine production. The result can be an exaggerated inflammatory response capable of inducing endoplasmic reticulum stress, which is responsible for various diseases. Due to the deleterious effects that this metabolite causes in its host, it is important to search for new therapeutic agents that allow a reduction in the TMAO levels of patients and that, thus, allow patients to be able to avoid a severe cardiovascular event. The present review discussed the synthesis of TMAO and its contribution to the pathogenesis of various inflammatory diseases.

Metabolomic profile of prostate cancer-specific survival among 1812 Finnish men

BACKGROUND

Abnormal metabolism and perturbations in metabolic pathways play significant roles in the development and progression of prostate cancer; however, comprehensive metabolomic analyses of human data are lacking and needed to elucidate the interrelationships.

METHODS

We examined the serum metabolome in relation to prostate cancer survival in a cohort of 1812 cases in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study. Using an ultrahigh-performance LC-MS/MS platform, we identified 961 known metabolites in prospectively collected serum. Median survival time from diagnosis to prostate cancer-specific death (N=472) was 6.6 years (interquartile range=2.9-11.1 years). Cox proportional hazards regression models estimated hazard ratios and 95% confidence intervals of the associations between the serum metabolites (in quartiles) and prostate cancer death, adjusted for age at baseline and diagnosis, disease stage, and Gleason sum. In order to calculate risk scores, we first randomly divided the metabolomic data into a discovery set (70%) and validated in a replication set (30%).

RESULTS

Overall, 49 metabolites were associated with prostate cancer survival after Bonferroni correction. Notably, higher levels of the phospholipid choline, amino acid glutamate, long-chain polyunsaturated fatty acid (n6) arachidonate (20:4n6), and glutamyl amino acids gamma-glutamylglutamate, gamma-glutamylglycine, and gamma-glutamylleucine were associated with increased risk of prostate cancer-specific mortality (fourth versus first quartile HRs=2.07-2.14; P-values <5.2×10^-5). By contrast, the ascorbate/aldarate metabolite oxalate, xenobiotics S-carboxymethyl-L-cysteine, fibrinogen cleavage peptides ADpSGEGDFXAEGGGVR and fibrinopeptide B (1-12) were related to reduced disease-specific mortality (fourth versus first quartile HRs=0.82-0.84; P-value <5.2×10^-5). Further adjustment for years from blood collection to cancer diagnosis, body mass index, smoking intensity and duration, and serum total and high-density lipoprotein cholesterol did not alter the results. Participants with a higher metabolic score based on the discovery set had an elevated risk of prostate cancer-specific mortality in the replication set (fourth versus first quartile, HR=3.9, P-value for trend<0.0001).

CONCLUSIONS

The metabolic traits identified in this study, including for choline, glutamate, arachidonate, gamma-glutamyl amino acids, fibrinopeptides, and endocannabinoid and redox pathways and their composite risk score, corroborate our previous analysis of fatal prostate cancer and provide novel insights and potential leads regarding the molecular basis of prostate cancer progression and mortality.

Gut Microbiome-Dependent Metabolic Pathways and Risk of Lethal Prostate Cancer: Prospective Analysis of a PLCO Cancer Screening Trial Cohort

BACKGROUND

Diet and the gut microbiome have a complex interaction that generates metabolites with an unclear effect on lethal prostate cancer risk. Identification of modifiable risk factors for lethal prostate cancer is challenging given the long natural history of this disease and difficulty of prospectively identifying lethal cancers.

METHODS

Mass spectrometry was performed on baseline serum samples collected from 173 lethal prostate cancer cases and 519 controls enrolled in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening trial. Baseline serum levels of choline, carnitine, betaine, γ-butyrobetaine, crotonobetaine, phenylacetylglutamine, hippuric acid, and p-cresol sulfate were quantified and analyzed by quartile. Conditional multivariable logistic regression analysis associated analyte levels with lethal prostate cancer incidence after adjusting for body mass index and PSA. The Cochran-Armitage test evaluated analyte level trends across quartiles.

RESULTS

Relative to those in the first quartile, cases with the highest baseline levels of choline (Q4 OR: 2.19; 95% CI, 1.23-3.90; P-trend: 0.005) and betaine (Q4 OR: 1.86; 95% CI, 1.05-3.30; P-trend: 0.11) exhibited increased odds of developing lethal prostate cancer. Higher baseline serum levels of phenylacetylglutamine (Q4 OR: 2.55; 95% CI, 1.40-4.64; P-trend: 0.003), a gut microbiome metabolite of phenylalanine with adrenergic activity, were also associated with lethal prostate cancer.

CONCLUSIONS

Baseline serum levels of one-carbon methyl donors and adrenergic compounds resulting from human and gut microbiota-mediated metabolism are associated with increased lethal prostate cancer risk.

IMPACT

Dietary composition, circulating metabolite levels, and downstream signaling pathways may represent modifiable risk factors associated with incident lethal prostate cancer. Beta-adrenergic blockade represents an additional target for oncologic risk reduction.

Emerging role of trimethylamine-N-oxide (TMAO) in colorectal cancer

Among gut microbiota-derived metabolites, trimethylamine-N-oxide (TMAO) is receiving increased attention due to its possible role in the carcinogenesis of colorectal cancer (CRC). In spite of numerous reports implicating TMAO with CRC, there is a lack of empirical mechanistic evidences to concretize the involvement of TMAO in the carcinogenesis of CRC. Possible mechanisms such as inflammation, oxidative stress, DNA damage, and protein misfolding by TMAO have been discussed in this review in the light of the latest advancements in the field. This review is an attempt to discuss the probable correlation between TMAO and CRC but this linkage can be concretized only once we get sufficient empirical evidences from the mechanistic studies. We believe, this review will augment the understanding of linking TMAO with CRC and will motivate researchers to move towards mechanistic study for reinforcing the idea of implicating TMAO with CRC causation. KEY POINTS: • TMAO is a gut bacterial metabolite which has been implicated in CRC in recent years. • The valid mechanistic approach of CRC causation by TMAO is unknown. • The article summarizes the possible mechanisms which need to be explored for validation.

Association between Dietary Choline Intake and Diabetic Retinopathy: National Health and Nutrition Examination Survey 2005-2008

PURPOSE

To explore whether there is an association between dietary choline intake and odds of diabetic retinopathy (DR) in the US diabetic population.

METHODS

A cross-sectional study was conducted using the combined data of the National Health and Nutrition Examination Survey (NHANES) 2005-2008 of a complex, multistage, and probability-sampling design. Energy-adjusted choline intake was calculated separately for men and women using the residual method. Binary logistic regression adjusting for covariates was used to identify the variables associated with DR.

RESULTS

We included 644 male and 628 female diabetic subjects, which were equivalent to a weighted survey sample of 9,339,124 for males and 10,109,553 for females respectively. Female DR patients consumed more choline than non-DR patients (268.6 mg/d vs 250.9 mg/d; p = .046). The estimated prevalence of DR was 17.4%, 21.9%, and 29.7% across three levels of dietary choline intake in females, respectively. In multivariable logistic-regression models, the odds ratio (OR) of DR for female patients in the highest choline intake group was 2.14 (95% confidence interval [CI], 1.38-3.31; p = .001) compared with those in the lowest intake group. This association was positive but not statistically significant in males.

CONCLUSION

Higher intake of dietary choline is associated with increased odds of DR in females, but not in males. Further studies are warranted to investigate the direct role of choline in DR development and determine the recommended daily intake of choline for diabetic patients weighing the pros and cons of dietary choline consumption.

Identification of lipidomic profiles associated with drug-resistant prostate cancer cells

Background

The association of circulating lipids with clinical outcomes of drug-resistant castration-resistant prostate cancer (DR-CRPC) is not fully understood. While it is known that increases in select lipids correlate to decreased survival, neither the mechanisms mediating these alterations nor the correlation of resistance to drug treatments is well characterized.

Methods

This gap-in-knowledge was addressed using in vitro models of non-cancerous, hormone-sensitive, CRPC and drug-resistant cell lines combined with quantitative LC-ESI-Orbitrap-MS (LC-ESI-MS/MS) lipidomic analysis and subsequent analysis such as Metaboanalyst and Lipid Pathway Enrichment Analysis (LIPEA).

Results

Several lipid regulatory pathways were identified that are associated with Docetaxel resistance in prostate cancer (PCa). These included those controlling glycerophospholipid metabolism, sphingolipid signaling and ferroptosis. In total, 7460 features were identified as being dysregulated between the cell lines studied, and 21 lipid species were significantly altered in drug-resistant cell lines as compared to nonresistant cell lines. Docetaxel resistance cells (PC3-Rx and DU145-DR) had higher levels of phosphatidylcholine (PC), oxidized lipid species, phosphatidylethanolamine (PE), and sphingomyelin (SM) as compared to parent control cells (PC-3 and DU-145). Alterations were also identified in the levels of phosphatidic acid (PA) and diacylglyceride (DAG), whose levels are regulated by Lipin (LPIN), a phosphatidic acid phosphatase that converts PA to DAG. Data derived from cBioPortal demonstrated a population of PCa patients expressing mutations aligning with amplification of LPIN1, LPIN2 and LPIN3 genes. Lipin amplification in these genes correlated to decreased survival in these patients. Lipin-1 mRNA expression also showed a similar trend in PCa patient data. Lipin-1, but not Lipin-2 or − 3, was detected in several prostate cancer cells, and was increased in 22RV1 and PC-3 cell lines. The increased expression of Lipin-1 in these cells correlated with the level of PA.

Conclusion

These data identify lipids whose levels may correlate to Docetaxel sensitivity and progression of PCa. The data also suggest a correlation between the expression of Lipin-1 in cells and patients with regards to prostate cancer cell aggressiveness and patient survivability. Ultimately, these data may be useful for identifying markers of lethal and/or metastatic prostate cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-021-01437-5.

Dietary choline, rather than betaine intake, is associated with hepatocellular carcinoma mortality

The dietary intakes of choline and betaine have been related to the mortality of some neoplasms, but their effects on hepatocellular carcinoma (HCC) mortality are still unknown. We examined the associations between dietary choline, five choline-containing compounds, different choline forms, betaine intake and HCC mortality. In total, 905 newly diagnosed HCC patients were enrolled in the Guangdong Liver Cancer Cohort study. Dietary intake was assessed by a valid food frequency questionnaire. Liver cancer-specific mortality (LCSM) and all-cause mortality (ACM) were calculated. Hazard ratios (HRs) and 95% confidence intervals (CIs) were computed by Cox proportional hazards models. It was found that a higher total choline intake was associated with lower ACM, Q4 vs. Q1: HR = 0.72, 95% CI: 0.53-0.97, Ptrend = 0.012 in the fully adjusted model. The associations between total choline intake and LCSM were not significant. Similar associations were found between water-soluble choline intake and HCC mortality, where the fully adjusted HR for ACM was 0.72, 95% CI: 0.53-0.98, Ptrend = 0.017. However, null associations were found between neither phosphatidylcholine (the most abundant lipid-soluble choline) nor total lipid-soluble choline intake and HCC mortality. These results implied that the favorable associations between the total choline intake and ACM were more attributed to water-soluble choline. Furthermore, no significant associations were observed between betaine intake and HCC mortality. Future human intervention trials regarding choline supplementation and liver disease recovery should take the forms into consideration rather than just the total amount alone.

Finding distinctions between oral cancer and periodontitis using saliva metabolites and machine learning

OBJECTIVE

The aim of this research is the study of metabolic pathways related to oral cancer and periodontitis along with development of machine-learning model for elucidation of these diseases based on saliva metabolites of patients.

METHODS

Data mining, metabolomic pathways analysis, study of metabolite-gene networks related to these diseases. Machine-learning and deep-learning methods for development of the model for recognition of oral cancer versus periodontitis, using patients' saliva.

RESULTS

The most accurate classifications between oral cancer and periodontitis were performed using neural networks, logistic regression and stochastic gradient descent confirmed by the separate 10-fold cross-validations. The best results were achieved by the deep-learning neural network with the TensorFlow program. Accuracy of the resulting model was 79.54%. The other methods, which did not rely on deep learning, were able to achieve comparable, although slightly worse results with respect to accuracy.

CONCLUSION

Our results demonstrate a possibility to distinguish oral cancer from periodontal disease by analysis the saliva metabolites of a patient, using machine-learning methods. These findings may be useful in the development of a non-invasive method to aid care providers in determining between oral cancer and periodontitis quickly and effectively.

Prostate cancer management: long-term beliefs, epidemic developments in the early twenty-first century and 3PM dimensional solutions

In the early twenty-first century, societies around the world are facing the paradoxal epidemic development of PCa as a non-communicable disease. PCa is the most frequently diagnosed cancer for men in several countries such as the USA. Permanently improving diagnostics and treatments in the PCa management causes an impressive divergence between, on one hand, permanently increasing numbers of diagnosed PCa cases and, on the other hand, stable or even slightly decreasing mortality rates. Still, aspects listed below are waiting for innovate solutions in the context of predictive approaches, targeted prevention and personalisation of medical care (PPPM / 3PM).A.PCa belongs to the cancer types with the highest incidence worldwide. Corresponding economic burden is enormous. Moreover, the costs of treating PCa are currently increasing more quickly than those of any other cancer. Implementing individualised patient profiles and adapted treatment algorithms would make currently too heterogeneous landscape of PCa treatment costs more transparent providing clear "road map" for the cost saving.B.PCa is a systemic multi-factorial disease. Consequently, predictive diagnostics by liquid biopsy analysis is instrumental for the disease prediction, targeted prevention and curative treatments at early stages.C.The incidence of metastasising PCa is rapidly increasing particularly in younger populations. Exemplified by trends observed in the USA, prognosis is that the annual burden will increase by over 40% in 2025. To this end, one of the evident deficits is the reactive character of medical services currently provided to populations. Innovative screening programmes might be useful to identify persons in suboptimal health conditions before the clinical onset of metastasising PCa. Strong predisposition to systemic hypoxic conditions and ischemic lesions (e.g. characteristic for individuals with Flammer syndrome phenotype) and low-grade inflammation might be indicative for specific phenotyping and genotyping in metastasising PCa screening and disease management. Predictive liquid biopsy tests for CTC enumeration and their molecular characterisation are considered to be useful for secondary prevention of metastatic disease in PCa patients.D.Particular rapidly increasing PCa incidence rates are characteristic for adolescents and young adults aged 15-40 years. Patients with early onset prostate cancer pose unique challenges; multi-factorial risks for these trends are proposed. Consequently, multi-level diagnostics including phenotyping and multi-omics are considered to be the most appropriate tool for the risk assessment, prediction and prognosis. Accumulating evidence suggests that early onset prostate cancer is a distinct phenotype from both aetiological and clinical perspectives deserving particular attention from view point of 3P medical approaches.

The Facts about Food after Cancer Diagnosis: A Systematic Review of Prospective Cohort Studies

Nutritional guidelines suggest specific energy and protein requirements for patients with cancer. However, cancer patients, often malnourished, use self-made or web-based diets to ameliorate the prognosis of their disease. This review aimed to investigate the associations between post-diagnostic diet and prognostic outcomes in cancer patients. A systematic literature search was performed in Pubmed and Web of Science databases from inception to 30 October 2019, based on fixed inclusion and exclusion criteria. The risk of bias was assessed. A total of 29 prospective studies was identified. Breast (n = 11), colorectal (n = 9), prostate (n = 8) cancers are the most studied. Low- fat diet, healthy quality diet, regular consumption of fiber such as vegetables and high-quality protein intake are beneficial while Western diet (WD) and high consumption of saturated fats could be associated with a higher risk of mortality. Bladder (n = 1), gynecological (n = 1), lung, stomach, and pancreatic cancers still remain almost unexplored. This systematic review suggested that detrimental dietary patterns such as WD should be avoided but none of the food categories (meat, dairy products) should be eliminated in cancer patients' diet. Further large prospective studies are needed to assess the role of post-diagnostic diet in patients with cancer.

Serum choline is associated with hepatocellular carcinoma survival: a prospective cohort study

BACKGROUND

Higher choline and betaine levels have been linked to lower risk of liver cancer, whereas existing data in relation to hepatocellular carcinoma (HCC) prognosis are scarce. Our objective was to examine the associations of the serum choline and betaine with HCC survival.

METHODS

866 newly diagnosed HCC patients were enrolled in the Guangdong Liver Cancer Cohort. Serum choline and betaine were assessed using high-performance liquid chromatography with online electro-spray ionization tandem mass spectrometry. Liver cancer-specific survival (LCSS) and overall survival (OS) were calculated. Cox proportional hazards models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

Serum choline levels were associated with better LCSS (T3 vs. T1: HR = 0.69, 95% CI: 0.51-0.94; P -trend < 0.05) and OS (T3 vs. T1: HR = 0.73, 95% CI: 0.54-0.99; P -trend < 0.05). The associations were significantly modified by C-reactive protein (CRP) levels but not by other selected prognostic factors including sex, age, etc. The favorable associations between serum choline and LCSS and OS were only existed among patients with CRP ≥3.0 mg/L. No significant associations were found between serum betaine levels and either LCSS or OS.

CONCLUSIONS

This study revealed that higher serum choline levels were associated with better HCC survival, especially in HCC patients with systemic inflammation status. No significant associations were found between serum betaine and HCC survival. Our findings suggest the benefits of choline on HCC survival.

TRIAL REGISTRATION

The Guangdong Liver Cancer Cohort was registered at clinicaltrials.gov as NCT03297255.

Small-Molecule Modulators of Sigma1 and Sigma2/TMEM97 in the Context of Cancer: Foundational Concepts and Emerging Themes

There are two known subtypes of the so-called sigma receptors, Sigma1 and Sigma2. Sigma1 (encoded by the SIGMAR1 gene and also known as Sigma-1 receptor, S1R) is a unique pharmacologically regulated integral membrane chaperone or scaffolding protein that allosterically modulates the activity of its associated proteins. Sigma2, recently identified as transmembrane protein 97 (TMEM97), is an integral membrane protein implicated in cellular cholesterol homeostasis. A number of publications over the past two decades have suggested a role for both sigma proteins in tumor biology. Although there is currently no clinically used anti-cancer drug that targets Sigma1 or Sigma2/TMEM97, a growing body of evidence supports the potential of small-molecule compounds with affinity for these proteins, putative sigma ligands, as therapeutic agents to treat cancer. In preclinical models, these compounds have been reported to inhibit cancer cell proliferation, survival, adhesion, and migration; furthermore, they have been demonstrated to suppress tumor growth, to alleviate cancer-associated pain, and to exert immunomodulatory properties. Here, we will address the known knowns and the known unknowns of Sigma1 and Sigma2/TMEM97 ligand actions in the context of cancer. This review will highlight key discoveries and published evidence in support of a role for sigma proteins in cancer and will discuss several fundamental questions regarding the physiological roles of sigma proteins in cancer and sigma ligand mechanism of action.

Trimethylamine-N-oxide as One Hypothetical Link for the Relationship between Intestinal Microbiota and Cancer - Where We Are and Where Shall We Go?

Previous epidemiological studies had provided evidence for a link between the microbial dysbiosis and cancer, particularly colorectal cancer (CRC), yet the molecular basis of this link remains elusive. Recently, the association between plasma levels of trimethylamine-N-oxide (TMAO), an oxidised form of trimethylamine (TMA), and risks of various cancers was demonstrated. The discovery could potentially provide an alternative explanation for the aforementioned link, as TMA production is attributed to intestinal bacteria. Current evidence suggests that inflammation could be a potential molecular mechanism to explain the link between TMAO and cancer, although other mechanisms such as oxidative stress, DNA damage and disruption in protein folding might also play a role. This mini-review article first provides an overview of the current evidence for the association between TMAO and certain cancer types, and the potential mechanisms that could explain their association. Thereafter, the direction of further research on the connection between the intestinal microbiota, TMAO and cancer is suggested.

Dietary choline and betaine intakes and risk of total and lethal prostate cancer in the Atherosclerosis Risk in Communities (ARIC) Study

PURPOSE

Two prior cohort studies suggested that choline, but not betaine intake, is associated with an increased risk of advanced prostate cancer (PCa). Given that evidence remains limited, we evaluated whether intakes of choline and derivative betaine are associated with total and lethal PCa risk and PCa death in men with PCa.

METHODS

We included 6,528 men (24.4% African American) without a cancer diagnosis at baseline (1987-1989) followed through 2012. Dietary intake was assessed using a food frequency questionnaire coupled with a nutrient database. We used Cox proportional hazards regression to estimate hazards ratios (HRs) and 95% confidence intervals (CIs) of total and lethal PCa risk overall and by race.

RESULTS

Choline intake was not associated with total (n = 811) or lethal (n = 95) PCa risk overall or by race. Betaine intake was inversely associated with lethal (tertile 3 vs 1, HR 0.59, 95% CI 0.35-1.00, p trend = 0.04), but not total PCa risk; patterns for lethal PCa were similar by race. Neither nutrient was associated with PCa death in men with PCa.

CONCLUSIONS

Choline intake was not associated with total or lethal PCa or with PCa death in men with PCa. Betaine intake was inversely associated with lethal, but not total PCa risk or with PCa death in men with PCa. Our results do not support the hypothesis that higher choline intake increases lethal PCa risk, but do suggest that higher betaine intake may be associated with lower lethal PCa risk. Further investigation with a larger number of lethal cases is needed.

Trimethylamine N-oxide, a gut microbiota-dependent metabolite of choline, is positively associated with the risk of primary liver cancer: a case-control study

BACKGROUND

Evidence has suggested a potential link exists between trimethylamine-N-oxide (TMAO), a choline-derived metabolite produced by gut microbiota, and some cancers, but little is known for primary liver cancer (PLC).

METHODS

A case-control study was designed including 671 newly diagnosed PLC patients and 671 control subjects frequency-matched by age (±5 years) and sex, in Guangdong province, China. High-performance liquid chromatography with online electrospray ionization tandem mass spectrometry (HPLC-MS/MS) was used to measure serum TMAO and choline. The associations between these biomarkers and PLC risk were evaluated using logistic regression models.

RESULTS

Serum TMAO concentrations were greater in the PLC group than the control group (P = 0.002). Logistic regression analysis showed that the sex- and age-adjusted odds ratio (OR) and (95% confidence interval [CI]) was 3.43 (2.42-4.86) when comparing the top and bottom quartiles (Q4 vs Q1). After further adjusting for more selected confounders, the OR (95% CI) remained significant but was attenuated to 2.85 (1.59-5.11) (Q4 vs Q1). The multivariable-adjusted ORs (95% CIs) across quartiles of choline were 0.35-0.15 (P -trend < 0.001).

CONCLUSION

Higher serum levels of TMAO were associated with increased PLC risk. The association was stronger in those with lower serum levels of choline. Additional large prospective studies are required to confirm these findings.

TRIAL REGISTRATION

This study was registered at clinicaltrials.gov as NCT 03297255.

Dietary Choline Intake: Current State of Knowledge Across the Life Cycle

Choline, an essential dietary nutrient for humans, is required for the synthesis of the neurotransmitter, acetylcholine, the methyl group donor, betaine, and phospholipids; and therefore, choline is involved in a broad range of critical physiological functions across all stages of the life cycle. The current dietary recommendations for choline have been established as Adequate Intakes (AIs) for total choline; however, dietary choline is present in multiple different forms that are both water-soluble (e.g., free choline, phosphocholine, and glycerophosphocholine) and lipid-soluble (e.g., phosphatidylcholine and sphingomyelin). Interestingly, the different dietary choline forms consumed during infancy differ from those in adulthood. This can be explained by the primary food source, where the majority of choline present in human milk is in the water-soluble form, versus lipid-soluble forms for foods consumed later on. This review summarizes the current knowledge on dietary recommendations and assessment methods, and dietary choline intake from food sources across the life cycle.

Association of choline and betaine levels with cancer incidence and survival: A meta-analysis

BACKGROUND & AIMS

Evidences suggest possible link between betaine and choline, methyl group donors, and cancer progression. We examined the association between choline and betaine levels and cancer incidence and survival in a meta-analysis of observational studies.

METHODS

We identified observational studies examining the association between choline and/or betaine levels from diet or blood and cancer incidence and survival by searching the PubMed and Web of Science databases for studies published up to Jan, 2018. After applying the selection criteria, 28 observational studies (9 case-control, 1 cross-sectional, and 18 cohort studies) were included. Relative risks (RRs) and 95% confidence intervals (CIs) were extracted, and combined RRs were calculated using random-effects models.

RESULTS

Choline levels were not associated with cancer incidence in a meta-analysis of cohort studies. Betaine levels reduced the risk of cancer incidence in a meta-analysis of cohort studies; combined relative risks (RRs) (95% CIs) comparing the top with the bottom categories were 0.93 (0.87-0.99). When we analyzed separately according to exposure assessment method, combined RRs (95% CIs) comparing the top with the bottom categories of betaine levels were 0.87 (95% CI: 0.78-0.95) for dietary betaine and 0.88 (95% CI: 0.77-0.99) for blood levels of betaine. There were no significant associations with cancer survivorship of choline or betaine levels.

CONCLUSIONS

We concluded that high betaine levels were associated with lower risk of the cancer incidence, especially for colorectal cancer.

Neuroprotective Actions of Dietary Choline

Choline is an essential nutrient for humans. It is a precursor of membrane phospholipids (e.g., phosphatidylcholine (PC)), the neurotransmitter acetylcholine, and via betaine, the methyl group donor S-adenosylmethionine. High choline intake during gestation and early postnatal development in rat and mouse models improves cognitive function in adulthood, prevents age-related memory decline, and protects the brain from the neuropathological changes associated with Alzheimer’s disease (AD), and neurological damage associated with epilepsy, fetal alcohol syndrome, and inherited conditions such as Down and Rett syndromes. These effects of choline are correlated with modifications in histone and DNA methylation in brain, and with alterations in the expression of genes that encode proteins important for learning and memory processing, suggesting a possible epigenomic mechanism of action. Dietary choline intake in the adult may also influence cognitive function via an effect on PC containing eicosapentaenoic and docosahexaenoic acids; polyunsaturated species of PC whose levels are reduced in brains from AD patients, and is associated with higher memory performance, and resistance to cognitive decline.

Higher dietary intakes of choline and betaine are associated with a lower risk of primary liver cancer: a case-control study

The dietary intake of methyl donors is favorably associated with many diseases, but the findings regarding primary liver cancer (PLC) risk are limited. This study investigated the association between the intake of choline, betaine and methionine and PLC risk in adults. This 1:1 matched case-control study enrolled 644 hospital-based PLC patients and 644 community-based controls who were matched by sex and age, in Guangzhou, China. An interviewer-administered questionnaire and a food-frequency questionnaire were used to collect general information and dietary intake information. Conditional logistic regression showed a significantly inverse association between total choline and betaine intakes and PLC risk. The multivariable-adjusted odds ratios (ORs) and their 95% confidence intervals (CIs) for PLC for the top (vs. bottom) tertile were 0.34 (0.24–0.49; P_-trend < 0.001) for total choline and 0.67 (0.48–0.93; P_-trend = 0.011) for betaine. No significant association was observed between the intake of methionine and PLC risk (P > 0.05). For individual choline compounds, higher consumptions of free choline, glycerophosphocholine, phosphocholine, phosphatidylcholine and sphingomyelin were associated with a lower PLC risk (all P-trend < 0.05). The studied associations were not significantly modified by the folate intake (P-interactions: 0.488–0.890). Our findings suggest that higher choline and betaine intakes may be associated with a lower risk of PLC.

Choline and betaine consumption lowers cancer risk: a meta-analysis of epidemiologic studies

A number of human and animal in vitro or in vivo studies have investigated the relationship between dietary choline and betaine and cancer risk, suggesting that choline and betaine consumption may be protective for cancer. There are also a few epidemiologic studies exploring this relationship, however, with inconsistent conclusions. The PubMed and Embase were searched, from their inception to March 2016, to identify relevant studies and we brought 11 articles into this meta-analysis eventually. The pooled relative risks (RRs) of cancer for the highest versus the lowest range were 0.82 (95% CI, 0.70 to 0.97) for choline consumption only, 0.86 (95%CI, 0.76 to 0.97) for betaine consumption only and 0.60 (95%CI, 0.40 to 0.90) for choline plus betaine consumption, respectively. Significant protective effect of dietary choline and betaine for cancer was observed when stratified by study design, location, cancer type, publication year, sex and quality score of study. An increment of 100 mg/day of choline plus betaine intake helped reduce cancer incidence by 11% (0.89, 95% CI, 0.87 to 0.92) through a dose-response analysis. To conclude, choline and betaine consumption lowers cancer incidence in this meta-analysis, but further studies are warranted to verify the results.

Prostate cancer progression and mortality: a review of diet and lifestyle factors

PURPOSE

To review and summarize evidence on the role of diet and lifestyle factors and prostate cancer progression, with a specific focus on habits after diagnosis and the risk of subsequent disease recurrence, progression, or death.

METHODS

Given the well-documented heterogeneity of prostate cancer and the long survivorship of the majority of diagnoses, our goal was to summarize and describe modifiable risk factors for clinically relevant prostate cancer. We focused where possible on epidemiologic studies of post-diagnostic habits and prostate cancer progression, defined as recurrence (e.g., PSA risk, secondary treatment), metastasis, or death. Where data were limited, we also describe evidence on risk factors and indicators of prostate cancer aggressiveness at diagnosis.

RESULTS

A variety of dietary and lifestyle factors appear to affect prostate cancer progression. Several generally widely recommended lifestyle factors such as not smoking, maintaining a healthy body weight, and regular vigorous physical exercise also appear to affect prostate cancer progression. Several dietary factors, such as tomato sauce/lycopene, cruciferous vegetables, healthy sources of vegetable fats, and coffee, may also have a role in reducing risk of prostate cancer progression.

CONCLUSION

Diet and lifestyle factors, in particular exercise and smoking cessation, may reduce the risk of prostate cancer progression and death. These promising findings warrant further investigation, as their overall impact might be large.

Associations between unprocessed red and processed meat, poultry, seafood and egg intake and the risk of prostate cancer: A pooled analysis of 15 prospective cohort studies

Reports relating meat intake to prostate cancer risk are inconsistent. Associations between these dietary factors and prostate cancer were examined in a consortium of 15 cohort studies. During follow-up, 52,683 incident prostate cancer cases, including 4,924 advanced cases, were identified among 842,149 men. Cox proportional hazard models were used to calculate study-specific relative risks (RR) and then pooled using random effects models. Results do not support a substantial effect of total red, unprocessed red and processed meat for all prostate cancer outcomes, except for a modest positive association for tumors identified as advanced stage at diagnosis (advanced(r)). For seafood, no substantial effect was observed for prostate cancer regardless of stage or grade. Poultry intake was inversely associated with risk of advanced and fatal cancers (pooled multivariable RR [MVRR], 95% confidence interval, comparing ≥ 45 vs. <5 g/day: advanced 0.83, 0.70-0.99; trend test p value 0.29), fatal, 0.69, 0.59-0.82, trend test p value 0.16). Participants who ate ≥ 25 versus <5 g/day of eggs (1 egg ∼ 50 g) had a significant 14% increased risk of advanced and fatal cancers (advanced 1.14, 1.01-1.28, trend test p value 0.01; fatal 1.14, 1.00-1.30, trend test p value 0.01). When associations were analyzed separately by geographical region (North America vs. other continents), positive associations between unprocessed red meat and egg intake, and inverse associations between poultry intake and advanced, advanced(r) and fatal cancers were limited to North American studies. However, differences were only statistically significant for eggs. Observed differences in associations by geographical region warrant further investigation.

The Emerging Hallmarks of Cancer Metabolism

Tumorigenesis is dependent on the reprogramming of cellular metabolism as both direct and indirect consequence of oncogenic mutations. A common feature of cancer cell metabolism is the ability to acquire necessary nutrients from a frequently nutrient-poor environment and utilize these nutrients to both maintain viability and build new biomass. The alterations in intracellular and extracellular metabolites that can accompany cancer-associated metabolic reprogramming have profound effects on gene expression, cellular differentiation, and the tumor microenvironment. In this Perspective, we have organized known cancer-associated metabolic changes into six hallmarks: (1) deregulated uptake of glucose and amino acids, (2) use of opportunistic modes of nutrient acquisition, (3) use of glycolysis/TCA cycle intermediates for biosynthesis and NADPH production, (4) increased demand for nitrogen, (5) alterations in metabolite-driven gene regulation, and (6) metabolic interactions with the microenvironment. While few tumors display all six hallmarks, most display several. The specific hallmarks exhibited by an individual tumor may ultimately contribute to better tumor classification and aid in directing treatment.

Choline and betaine intake and colorectal cancer risk in Chinese population: a case-control study

Background

Few studies have examined the association of choline and betaine intake with colorectal cancer risk, although they might play an important role in colorectal cancer development because of their role as methyl donors. The aim of this study was to examine the relationship between consumption of choline and betaine and colorectal cancer risk in a Chinese population.

Methodology/Principal Findings

A case-control study was conducted between July 2010 and December 2013 in Guangzhou, China. Eight hundred and ninety consecutively recruited colorectal cancer cases were frequency matched to 890 controls by age (5-year interval) and sex. Dietary information was assessed with a validated food frequency questionnaire by face-to-face interviews. The logistic regression model was used to estimate multivariate odds ratios (ORs) and 95% confidence intervals (CIs). Total choline intake was inversely associated with colorectal cancer risk after adjustment for various lifestyle and dietary factors. The multivariate-adjusted OR was 0.54 (95%CI = 0.37-0.80, Ptrend <0.01) comparing the highest with the lowest quartile. No significant associations were observed for betaine or total choline+betaine intakes. For choline-containing compounds, lower colorectal cancer risk was associated with higher intakes of choline from phosphatidylcholine, glycerophosphocholine and sphingomyelin but not for free choline and phosphocholine. The inverse association of total choline intake with colorectal cancer risk was observed in both men and women, colon and rectal cancer. These inverse associations were not modified by folate intake.

Conclusions

These results indicate that high intake of total choline is associated with a lower risk of colorectal cancer.

Potential role of gastrointestinal microbiota composition in prostate cancer risk

Background

Among men in the U.S., prostate cancer is the most common cancer and the second leading cause of cancer death. Despite its prevalence, there are few established risk factors for prostate cancer. Some studies have found that intake of certain foods/nutrients may be associated with prostate cancer risk, but few have accounted for how intake and metabolic factors may interact to influence bioavailable nutrient levels and subsequent disease risk.

Presentation of the hypothesis

The composition of the gastrointestinal (GI) microbiome may influence metabolism of dietary compounds and nutrients (e.g., plant phenols, calcium, choline) that may be relevant to prostate cancer risk. We, therefore, propose the hypothesis that GI microbiota may have a markedly different composition among individuals with higher prostate cancer risk. These individuals could have microbial profiles that are conducive to intestinal inflammation and/or are less favorable for the metabolism and uptake of chemopreventive agents.

Testing the hypothesis

Because very little preliminary data exist on this potential association, a case–control study may provide valuable information on this topic. Such a study could evaluate whether the GI microbial profile is markedly different between three groups of individuals: healthy men, those with latent prostate cancer, and those with invasive prostate cancer. Any findings could then be validated in a larger study, designed to collect a series of specimens over time.

Implications of the hypothesis

Given the plethora of information emerging from the Human Microbiome Project, this is an opportune time to explore associations between the microbiome and complex human diseases. Identification of profiles that alter the host’s risk for disease may clarify inconsistencies in the literature on dietary factors and cancer risk, and could provide valuable targets for novel cancer prevention strategies.

Choline and betaine intakes are associated with reduced risk of nasopharyngeal carcinoma in adults: a case-control study

Background:

Intakes of choline and betaine have been inversely related to the risk of various neoplasms, but scant data exist on nasopharyngeal carcinoma (NPC). We examined the association between consumption of choline and betaine and risk of NPC.

Methods:

We conducted a case–control study with 600 incident NPC patients and 600 controls 1 : 1 matched by age, sex and household type in Guangdong, China. Dietary intake was assessed by a food frequency questionnaire through face-to-face interview.

Results:

Intakes of total choline, betaine and choline+betaine were inversely related to NPC after adjustment for various lifestyle and dietary factors (all P-trend <0.001). Adjusted odds ratios (95% CI) for quartile 4 (vs quartile 1) were 0.42 (0.29, 0.61) for total choline, 0.50 (0.35, 0.72) for betaine and 0.44 (0.30, 0.64) for betaine+total choline. Regarding various sources of choline, lower NPC risk was associated with greater intakes of choline from phosphatidylcholine, free choline, glycerophosphocholine and phosphocholine, but not sphingomyelin.

Conclusion:

These findings are consistent with a beneficial effect of choline and betaine intakes on carcinogenesis.