Loss of hexokinase 1 sensitizes ovarian cancer to high-dose metformin

Background Hexokinases (HKs) are well-studied enzymes catalyzing the first step of glycolysis. However, non-canonical regulatory roles of HKs are still incompletely understood. Here, we hypothesized that HKs comprise one of the missing links between high-dose metformin and the inhibition of the respiratory chain in cancer. Methods We tested the isoenzyme-specific regulatory roles of HKs in ovarian cancer cells by examining the effects of the deletions of HK1 and HK2 in TOV-112D ovarian adenocarcinoma cells. We reverted these effects by re-introducing wild-type HK1 and HK2, and we compared the HK1 revertant with the knock-in of catalytically dead HK1 p.D656A. We subjected these cells to a battery of metabolic and proliferation assays and targeted GC×GC-MS metabolomics. Results We found that the HK1 depletion (but not the HK2 depletion) sensitized ovarian cancer cells to high-dose metformin during glucose starvation. We confirmed that this newly uncovered role of HK1 is glycolysis-independent by the introduction of the catalytically dead HK1. The expression of catalytically dead HK1 stimulated similar changes in levels of TCA intermediates, aspartate and cysteine, and in glutamate as were induced by the HK2 deletion. In contrast, HK1 deletion increased the levels of branched amino acids; this effect was completely eliminated by the expression of catalytically dead HK1. Furthermore, HK1 revertants but not HK2 revertants caused a strong increase of NADPH/NADP ratios independently on the presence of glucose or metformin. The HK1 deletion (but not HK2 deletion) suppressed the growth of xenotransplanted ovarian cancer cells and nearly abolished the tumor growth when the mice were fed the glucose-free diet. Conclusions We provided the evidence that HK1 is involved in the so far unknown glycolysis-independent HK1–metformin axis and influences metabolism even in glucose-free conditions.

Branched-Chain amino acids intake is negatively related to body adiposity in individuals at cardiometabolic risk

ABSTRACT Objective To assess the relationship between branched-chain amino acids intake in the current diet and the metabolic and body adiposity markers in a population at cardiovascular risk. Methods This is a cross-sectional study with 282 adults and elderly people from the Cardiovascular Health Care Program of the Universidade Federal de Viçosa. Sociodemographic, anthropometric and body composition data, as well as metabolic biomarkers were collected using standardized protocols. Dietary intake of branched amino acids was assessed using a 24-hour recall. Results Individuals with a higher branched-chain amino acids intake (≥2.6g/day, median value) had lower body fat (29.6 vs 32.2%; p=0.019), and higher serum ferritin (113.2 vs. 60.1mg/dL; p=0.006) and uric acid concentrations (4.4 vs. 4.0; p=0.023). In addition, a lower prevalence of overweight and excessive abdominal fat (p<0.05) was found in the individuals with higher branched-chain amino acids intake. They also had a higher daily intake of fiber, copper, zinc, magnesium, and iron, as well as a lower intake of total lipids. Conclusion In the present study, the intake of branched amino acids is negatively related to total and central adiposity, but more studies are needed to fully elucidate this possible relationship. (Brazilian Registry of Clinical Trials, code RBR-5n4y2g).

Plasma metabolomics and clinical predictors of survival differences in COPD patients

Background Plasma metabolomics profile (PMP) in COPD has been associated with clinical characteristics, but PMP’s relationship to survival has not been reported. We determined PMP differences between patients with COPD who died an average of 2 years after enrollment (Non-survivors, NS) compared to those who survived (S) and also with age matched controls (C). Methods We studied prospectively 90 patients with severe COPD and 30 controls. NS were divided in discovery and validation cohorts (30 patients each) and the results compared to the PMP of 30 S and C. All participants completed lung function tests, dyspnea scores, quality of life, exercise capacity, BODE index, and plasma metabolomics by liquid and gas chromatography / mass spectometry (LC/MS, LC/MS2, GC/MS). Statistically, we used Random Forest Analysis (RFA) and Support Vector Machine (SVM) to determine metabolites that differentiated the 3 groups and compared the ability of metabolites vs. clinical characteristics to classify patients into survivors and non-survivors. Results There were 79 metabolites statistically different between S and NS [p < 0.05 and false discovery rate (q value) < 0.1]. RFA and SVM classification of COPD survivors and non-survivors had a predicted accuracy of 74 and 85% respectively. Elevation of tricyclic acid cycle intermediates branched amino acids depletion and increase in lactate, fructose and xylonate showed the most relevant differences between S vs. NS suggesting alteration in mitochondrial oxidative energy generation. PMP had similar predictive power for risk of death as information provided by clinical characteristics. Conclusions A plasma metabolomic profile characterized by an oxidative energy production difference between survivors and non-survivors was observed in COPD patients 2 years before death.

Evaluation of Pancreatic and Extra Pancreatic Effects of Branched Amino Acids

Background and aims: Leucine, Isoleucine, and Valine collectively known as Branched-chain amino acids (BCAAs), can be closely associated with metabolic dysregulates and with insulin resistance. We aimed to explore the role of BCAAs as potential treatment option for diabetes. Material and method: Bioassay the effect of BCAAs on MIN6 cell line on insulin secretion and pancreatic beta cells expansion, then were checked for inhibitory potential of pancreatic amylase, glucosidase and lipase as alternative approach for diabetes treatment. Results: BCAAs significantly enhance insulin secretion parallel to L-alanine efficacy. Furthermore, BCAAs obtain a dose dependent β-cell proliferation similar to glucagon-like peptide-1. Moreover, these acids could restore the secretory function of MIN6 β-cell despite stressful gluco-lipo-toxicity; separately or combined. Moreover, BCAAs exerted a dose dependent dual inhibition of amylase, glucosidase and lipase. Conclusions: Our current findings suggest that BCAAs supplementation may have a potential therapeutic effect against diabetes as insulin releasing agent and as specific inhibitors for both-amylase/α-amyloglucoside and lipase

Nutritional evaluation of mixed wheat–faba bean pasta in growing rats: impact of protein source and drying temperature on protein digestibility and retention

This study aimed to evaluate the nutritional value of pasta enriched with legume or wheat gluten proteins and dried at varying temperature. A total of four isonitrogenous experimental diets were produced using gluten powder/wheat semolina (6/94, g/g) pasta and faba bean flour/wheat semolina (35/65, g/g) pasta dried at either 55°C (GLT and FLT, respectively) or 90°C (FVHT and GVHT, respectively). Experimental diets were fed to ten 1-month-old Wistar rats (body weight=176 (sem 15) g) for 21 d. Growth and nutritional, metabolic and inflammatory markers were measured and compared with an isonitrogenous casein diet (CD). The enrichment with faba bean increased the lysine, threonine and branched amino acids by 97, 23 and 10 %, respectively. Protein utilisation also increased by 75 % (P<0·01) in FLT in comparison to GLT diet, without any effect on the corrected faecal digestibility (P>0·05). Faba bean pasta diets' corrected protein digestibility and utilisation was only 3·5 and 9 %, respectively, lower than the CD. Growth rate, blood composition and muscle weights were not generally different with faba bean pasta diets compared with CD. Corrected protein digestibility was 3 % lower in GVHT than GLT, which may be associated with greater carboxymethyllysine. This study in growing rats clearly indicates improvement in growth performance of rats fed legume-enriched pasta diet compared with rats fed gluten–wheat pasta diet, regardless of pasta drying temperature. This means faba bean flour can be used to improve the protein quality and quantity of pasta.