Nutrients related to one-carbon metabolism and risk of renal cell cancer

Folic acid: friend or foe in cancer therapy

Folic acid plays a crucial role in diverse biological processes, notably cell maturation and proliferation. Here, we performed a literature review using articles listed in electronic databases, such as PubMed, Scopus, MEDLINE, and Google Scholar. In this review article, we describe contradictory data regarding the role of folic acid in cancer development and progression. While some studies have confirmed its beneficial effects in diminishing the risk of various cancers, others have reported a potential carcinogenic effect. The current narrative review elucidates these conflicting data by highlighting the possible molecular mechanisms explaining each point of view. Further multicenter molecular and genetic studies, in addition to human randomized clinical trials, are necessary to provide a more comprehensive understanding of the relationship between folic acid and cancer.

Fabrication of poly(t-butyl betaine carboxylate)-based nanoparticles and study on their in vivo biosecurity

The purpose of this article was to fabricate the novel poly(t-butyl betaine carboxylate)-S-S-poly (1, 3-dioxan-2-one) nanoparticles (PCB-tBU-S-S-PDI NPs) and study their in vivo biosecurity. The poly(t-butyl betaine carboxylate) (PCB-tBU) segment was conjugated to the poly(1, 3-dioxan-2-one)(PDI) moity with a disulfide bond to obtain the copolymer PCB-tBU-S-S-PDI. Hydrogen nuclear magnetic resonance (¹H NMR) and Fourier transform infrared spectroscopy (FTIR) spectra were applied to study the structure of PCB-tBU-S-S-PDI. The cargo-free NPs were administrated to Sprague-Dawley (SD) rats by intraperitoneal injection every 3 days for 30 days. Then, the blood routine examination, blood biochemistry, and histologic slides of rat's organs were carried out to monitor the in vivo biosecurity of cargo-free PCB-tBU-S-S-PDI NPs. ¹H NMR and FTIR spectra confirmed the successfully synthesis of PCB-tBU-S-S-PDI. The cargo-free NPs showed spherical morphology with an average of 139.8 ± 0.26 nm. The results of blood biochemistry and blood routine examination suggested that the cargo-free PCB-tBU-S-S-PDI NPs did not show any influence on the liver and renal functions of treated rats. Significantly, the physiological slides of treated rat's organs did not show any physiological and pathological changes. These phenomena suggested that the PCB-tBU-S-S-PDI NPs had good biosecurity, and it could be used as a vehicle for antineoplastic drug delivery.

Components of one-carbon metabolism and renal cell carcinoma: a systematic review and meta-analysis

PURPOSE

Little is known about the aetiology of renal cell carcinoma (RCC). Components of one-carbon (1C) metabolism, which are required for nucleotide synthesis and methylation reactions, may be related to risk of RCC but existing evidence is inconclusive. We conducted a systematic review and independent exposure-specific meta-analyses of dietary intake and circulating biomarkers of 1C metabolites and RCC risk.

METHODS

Medline and Embase databases were searched for observational studies investigating RCC or kidney cancer incidence or mortality in relation to components of 1C metabolism and 12 eligible articles were included in the meta-analyses. We used Bayesian meta-analyses to estimate summary relative risks (RRs) and 95% credible intervals (CrIs) comparing the highest versus lowest categories as well as the between-study heterogeneity.

RESULTS

We did not find convincing evidence of an association between any exposure (riboflavin, vitamin B6, folate, vitamin B12, methionine, homocysteine, choline, or betaine) and RCC risk. However, vitamin B6 biomarker status did have a protective (RR = 0.62) but imprecise (95% CrI 0.39-1.14) effect estimate and folate intake had a notable association as well (RR = 0.85, 95% CrI 0.71-1.01).

CONCLUSION

There was a lack of precision due largely to the low number of studies. Further investigation is warranted, especially for folate and vitamin B6, which had consistent suggestive evidence of a protective effect for both dietary intake and biomarker status. A unique strength of this review is the use of Bayesian meta-analyses which allowed for robust estimation of between-study heterogeneity.

Metabolomics in renal cell carcinoma: From biomarker identification to pathomechanism insights

Renal cell carcinoma (RCC) is a frequently diagnosed cancer with high prevalence, which is inversely associated with survival benefit. Although myriad studies have shed light on disease causality, unfortunately, thus far, RCC diagnosis is faced with numerous obstacles partly due to the insufficient knowledge of effective biomarkers, hinting deeper mechanistic understanding are urgently needed. Metabolites are recognized as final proxies for gene-environment interactions and physiological homeostasis as they reflect dynamic processes that are ongoing or have been taken place, and metabolomics may therefore offer a far more productive and cost-effective route to disease discovery, particularly within the arena for new biomarker identification. In this review, we primarily expatiate recent advances in metabolomics that may be amenable to novel biomarkers or therapeutic targets for RCC, which may expand our armaments to win more bettles against RCC.

Relationship between serum B12 concentrations and mortality: experience in NHANES

BACKGROUND

There is conflicting evidence in the literature on the association between (elevated) serum B12 concentrations and subsequent disease or mortality. We evaluated in the NHANES general population the association of serum B12 concentrations as well as vitamin B12 supplement intake with all-cause, cardiovascular, and cancer-related mortality, while taking into account demographic and lifestyle factors and significant other diseases which are known to be associated with poorer outcome.

METHODS

The main outcomes of our study were all-cause mortality, cardiovascular mortality, and cancer-related mortality. Mortality status and cause of death were determined by NHANES-linked National Death Index public access files through December 31, 2015. The association of serum B12 concentrations and vitamin B12 supplement intake with mortality was assessed with Cox proportional hazard (PH) models, with adjustment for a number of relevant demographic and lifestyle factors and comorbidity.

RESULTS

The final study population of 24,262 participants had a mean age of 48 (SD 19) years; 50.1% were males. The median follow-up duration was 109 months (range 1-201 months). On the census day of December 31, 2015, 3023 participants were determined as deceased (12.5%). The fully adjusted Cox PH model indicated that low serum B12 concentrations < 140 pmol/l were associated with a small increase in all-cause (hazard ratio, HR 1.39, 95% CI 1.08-1.78, p = 0.011) and cardiovascular (HR 1.64, 95% CI 1.08-2.47, p = 0.020) mortality. Similarly, high serum B12 concentrations > 700 pmol/l were associated with an increase in cardiovascular mortality only (HR 1.45, 95% CI 1.01-2.06, p = 0.042). Participants with a diagnosis of hypertension, dyslipidemia, CVD, and cancer more frequently used vitamin B12-containing supplements than those without these diagnoses. We could not demonstrate an association between vitamin B12 supplement intake and mortality, when adjusted for comorbidity.

CONCLUSIONS

In the general population of NHANES, low serum B12 concentrations were associated with a moderate increase in all-cause mortality. There was a small but significant increase in cardiovascular mortality in the groups with low or high serum B12. High intake of vitamin B12 in the form of supplements was not associated with any adverse effect on mortality and therefore can be regarded as safe.

Prognostic value of D-lactate dehydrogenase in patients with clear cell renal cell carcinoma

Lactate dehydrogenase (LDH) is an enzyme involved in anaerobic glycolysis and is associated with the prognosis of patients with renal cell carcinoma (RCC). The human genome has four LDH genes: LDHA, LDHB, LDHC and LDHD. In order to determine which of these four LDH genes may predict clear cell RCC (ccRCC), a total of 509 patients with ccRCC from The Cancer Genome Atlas (TCGA) cohort and 192 patients with ccRCC from the Fudan University Shanghai Cancer Centre (FUSCC) cohort were enrolled in the present study. The expression profiles of LDHD genes in the TCGA cohort were obtained from the TCGA RNAseq database. The Cox proportional hazards regression model and Kaplan-Meier curves were used to assess relative factors. The LDH family genes that were revealed to have an association with overall survival (OS) were further validated in the FUSCC cohort. In the TCGA cohort, following Cox proportional hazards analysis, LDHD expression (P=0.0400; hazard ratio, 0.872; 95% confidence interval, 0.764-0.994) was revealed to be predictive of the prognosis of patients with ccRCC. Further analysis revealed that low LDHD expression (P<0.0001) was significantly associated with a poor prognosis in terms of OS. Additionally, the expression of LDHD (P<0.0001) was significantly different in patients with ccRCC compared with paired controls. In the FUSCC cohort, low LDHD expression was also associated with a poor OS (P=0.0103), and the tumour pathological T stage was a factor that influenced the expression of LDHD (P=0.0120). Furthermore, the expression of LDHD influenced the serum LDH level (P=0.0126). The downregulation of LDHD expression may be a predictor of poor prognosis in patients with ccRCC.

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.

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.

One-Carbon Metabolic Factors and Risk of Renal Cell Cancer: A Meta-Analysis

BACKGROUND

Nutrients related to one-carbon metabolism were previously shown to be significantly associated with the risk of cancer. The aim of this meta-analysis was to evaluate potential relationships between one-carbon metabolic factors and renal cell cancer (RCC) risk.

METHODS

PubMed, EMBASE, and Cochrane Library databases were searched through March 2015 for observational studies of quantitative RCC risk estimates in relation to one-carbon metabolic factors. The relative risks (RRs) with 95% confidence intervals (CIs) measured the relationship between one-carbon metabolic factors and RCC risk using a random-effects model.

RESULTS

Of the 463 citations and abstracts identified by database search, seven cohorts from five observational studies reported data on 133,995 individuals, and included 2,441 RCC cases. Comparing the highest with the lowest category, the pooled RRs of RCC were 0.72 (95%CI: 0.52-1.00; P = 0.048) for vitamin B12. In addition, an increase in folic acid supplementation of 100 μg/day was associated with a 3% lower risk of RCC (RR, 0.97; 95%CI: 0.93-1.00; P = 0.048). Similarly, an increase of 5 nmol/L of vitamin B2 was associated with a reduced risk of RCC 0.94 (95%CI: 0.89-1.00; P = 0.045). Sensitivity analyses suggested that a higher serum vitamin B6 might contribute to a reduced risk of RCC (RR, 0.83; 95%CI: 0.77-0.89; P < 0.001).

CONCLUSIONS

Higher levels of serum vitamin B2, B6, B12, and folic acid supplementation lowered the risk of RCC among the study participants.

Derivation and validation of homocysteine score in u.s. Men and women

BACKGROUND

One-carbon metabolism, which is crucial in DNA synthesis and genomic stability, is an interrelated network of biochemical reactions involved in several dietary and lifestyle factors. The development of the homocysteine score using these factors may be useful to reflect the status of one-carbon metabolism in large epidemiologic studies without biologic samples to measure homocysteine directly.

OBJECTIVE

The aim of this study was to develop an homocysteine score that reflects one-carbon metabolism better than individual dietary or lifestyle factors.

METHODS

We divided 2023 participants with measured plasma total homocysteine data in the Nurses' Health Study and the Health Professionals Follow-Up Study into training (n = 1619) and testing (n = 404) subsets. Using multivariable linear regression, we selected lifestyle determinants of plasma homocysteine in the training set and derived the homocysteine score weighted by the β coefficient for each predictor. The validation of the homocysteine score was assessed using the plasma homocysteine in the independent samples of the training set.

RESULTS

In the training set, smoking, multivitamin use, and caffeine, alcohol, and dietary and supplemental folate intake were significant independent determinants of plasma homocysteine in multivariable linear regression (P ≤ 0.01) and were included in the derivation of the homocysteine score. The Pearson correlation of the homocysteine score with plasma homocysteine was 0.30 in the testing subset (P < 0.001). The homocysteine score was positively associated with the plasma homocysteine concentration in the testing subset and in an independent population of women; the mean difference of plasma homocysteine concentration between the extreme quintiles of homocysteine score ranged from 0.83 μmol/L to 1.52 μmol/L. Population misclassification either from the lowest quintile of plasma homocysteine into the highest quintile of the homocysteine score or from the highest quintile of plasma homocysteine into the lowest quintile of the homocysteine score was ≤12%.

CONCLUSION

These data indicate that the homocysteine score may be used with relatively inexpensive and simple questionnaires to rank an individual's one-carbon metabolism status when homocysteine data are not available.

Circulating biomarkers of one-carbon metabolism in relation to renal cell carcinoma incidence and survival

BACKGROUND

The etiology of renal cell carcinoma (RCC) is only partially understood, but a metabolic component appears likely. We investigated biomarkers of one-carbon metabolism and RCC onset and survival.

METHODS

The European Prospective Investigation into Cancer and Nutrition (EPIC) recruited 385747 participants with blood samples between 1992 and 2000, and this analysis included 556 RCC case-control pairs. A subsequent replication study included 144 case-control pairs nested within the Melbourne Collaborative Cohort Study (MCCS). Plasma concentrations of vitamin B2, vitamin B6, folate, vitamin B12, methionine and homocysteine were measured in prediagnostic samples and evaluated with respect to RCC risk using conditional and unconditional logistic regression models, and to all-cause mortality in RCC cases using Cox regression models. All statistical tests were two-sided.

RESULTS

EPIC participants with higher plasma concentrations of vitamin B6 had lower risk of RCC, the odds ratio comparing the 4(th) and 1(st) quartiles (OR4vs1) being 0.40 95% confidence interval [CI] = 0.28 to 0.57, P trend < .001. We found similar results after adjusting for potential confounders (adjusted P trend < .001). In survival analysis, the hazard ratio for all-cause mortality in RCC cases when comparing the 4(th) and 1(st) quartiles (HR4vs1) of vitamin B6 was 0.57 (95% CI = 0.37 to 0.87, P trend < .001). Subsequent replication of these associations within the MCCS yielded very similar results for both RCC risk (OR4vs1 = 0.47, 95% CI = 0.23 to 0.99, P trend = .07) and all-cause mortality (HR4vs1 = 0.56, 95% CI = 0.27 to 1.17, P trend = .02). No association was evident for the other measured biomarkers.

CONCLUSION

Study participants with higher circulating concentrations of vitamin B6 had lower risk of RCC and improved survival following diagnosis in two independent cohorts.

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.