Polymorphisms of folate metabolism genes in patients with cirrhosis and hepatocellular carcinoma

AIM To evaluated the association of the risk factors and polymorphisms in MTHFR C677 T, MTHFR A1298 C, MTR A2756 G and MTRR A66 G genes.METHODS Patients with cirrhosis(n = 116), hepatocellular carcinoma(HCC)(n = 71) and controls(n = 356) were included. Polymerase chain reaction followed by enzymatic digestion and allelic discrimination technique real-time PCR techniques were used for analysis. MINITAB-14.0and SNPstats were utilized for statistical analysis. RESULTS Showed that age ≥ 46 years(OR = 10.31; 95%CI: 5.66-18.76; P < 0.001) and smoking(OR = 0.47; 95%CI: 0.28-0.78; P = 0.003) were associated with cirrhosis. Age ≥ 46 years(OR = 16.36; 95%CI: 6.68-40.05; P < 0.001) and alcohol habit(OR = 2.01; 95%CI: 1.03-3.89; P = 0.039) were associated with HCC. MTHFR A1298 C in codominant model(OR = 3.37; 95%CI: 1.52-7.50; P = 0.014), recessive model(OR = 3.04; 95%CI: 1.43-6.47; P = 0.0051) and additive model(OR = 1.71; 95%CI: 1.16-2.52; P = 0.0072) was associated with HCC, as well as MTR A2756 G in the additive model(OR = 1.68; 95%CI: 1.01-2.77; P = 0.047), and MTRR A66 G in the codominant model(OR = 3.26; 95%CI: 1.54-6.87; P < 0.001), dominant model(OR = 2.55; 95%CI: 1.24-5.25; P = 0.007) and overdominant model(OR = 3.05; 95%CI: 1.66-5.62; P < 0.001). MTR A2756 G in the additive model(OR = 1.54; 95%CI: 1.02-2.33; P = 0.042) and smokers who presented at least one polymorphic allele for MTRR A66G(OR = 1.71; 95%CI: 0.77-3.82; P = 0.0051) showed increased risk for cirrhosis. There was no association between clinical parameters and polymorphisms. CONCLUSION Age ≥ 46 years, alcohol habit and MTR A2756 G, MTHFR A1298 C and MTRR A66 G polymorphisms are associated with an increased risk of HCC development; age ≥ 46 years, tobacco habit and the MTR A2756 G polymorphism are associated with cirrhosis.

Deacetylation of MTHFD2 by SIRT4 senses stress signal to inhibit cancer cell growth by remodeling folate metabolism

Folate metabolism plays an essential role in tumor development.Various cancers display therapeutic response to reagents targeting key enzymes of the folate cycle,but obtain chemoresistance later.Therefore,novel targets in folate metabolism are highly demanded.Methylenetetrahydrofolate dehydrogenase/methylenetetrahydrofolate cyclohydrolase 2(MTHFD2)is one of the key enzymes in folate metabolism and its expression is highly increased in mutiple human cancers.However,the underlying mechanism that regulates MTHFD2 expression remains unknown.Here,we elucidate that SIRT4 deacetylates the conserved lysine 50(K50)residue in MTHFD2.K50 deacetylation destabilizes MTHFD2 by elevating cullin 3 E3 ligase-mediated proteasomal degradation in response to stressful stimuli of folate deprivation,leading to suppression of nicotinamide adenine dinucleotide phosphate production in tumor cells and accumulation of intracellular reactive oxygen species,which in turn inhibits the growth of breast cancer cells.Collectively,our study reveals that SIRT4 senses folate availability to control MTHFD2 K50 acetylation and its protein stability,bridging nutrient/folate stress and cellular redox to act on cancer cell growth.

Two folate-derived analogues from an aqueous decoction of Uncaria rhynchophylla

Two new folate-derived analogues,named uncarophyllofolic acids A(1)and B(2),respectively,were isolated from the Uncaria rhynchophylla hook bearing stem(Gouteng in Chinese).The distinct stereochemical structures of 1 and 2 were determined by spectroscopic data analysis in combination with acidic hydrolysis and Marfey’s derivatization,along with comparison of their specific rotation and Cotton effect(CE)data with those of the biogenetically related known derivatives as well as theoretical calculations of electronic circular dichroism(ECD)spectra.A plausible biosynthetic pathway of 1 and 2,associating to folate metabolism and the previously reported orychophragines A-C from Orychophragmus violaceus,is discussed.

Use of recombinant microRNAs as antimetabolites to inhibit human non-small cell lung cancer

During the development of therapeutic microRNAs(miRNAs or miRs),it is essential to define their pharmacological actions.Rather,miRNA research and therapy mainly use miRNA mimics synthesized in vitro.After experimental screening of unique recombinant miRNAs produced in vivo,three lead antiproliferative miRNAs against human NSCLC cells,miR-22-3p,miR-9-5p,and miR-218-5p,were revealed to target folate metabolism by bioinformatic analyses.Recombinant miR-22-3p,miR-9-5p,and miR-218-5p were shown to regulate key folate metabolic enzymes to inhibit folate metabolism and subsequently alter amino acid metabolome in NSCLC A549 and H1975 cells.Isotope tracing studies further confirmed the disruption of one-carbon transfer from serine to folate metabolites by all three miRNAs,inhibition of glucose uptake by miR-22-3p,and reduction of serine biosynthesis from glucose by miR-9-5p and-218-5p in NSCLC cells.With greater activities to interrupt NSCLC cell respiration,glycolysis,and colony formation than miR-9-5p and-218-5p,recombinant miR-22-3p was effective to reduce tumor growth in two NSCLC patient-derived xenograft mouse models without causing any toxicity.These results establish a common antifolate mechanism and differential actions on glucose uptake and metabolism for three lead anticancer miRNAs as well as antitumor efficacy for miR-22-3p nanomedicine,which shall provide insight into developing antimetabolite RNA therapies.

Crystal structure of Arabidopsis thaliana HPPK/DHPS,a bifunctional enzyme and target of the herbicide asulam

Herbicides are vital formodern agriculture,but their utility is threatened by genetic or metabolic resistance in weeds,as well as regulatory barriers.Of the known herbicide modes of action,7,8-dihydropterin synthase(DHPS),which is involved in folate biosynthesis,is targeted by just one commercial herbicide,asulam.A mimic of the substrate para-aminobenzoic acid,asulam is chemically similar to sulfonamide antibiotics,and although it is still in widespread use,asulam has faced regulatory scrutiny.With an entire mode of action represented by just one commercial agrochemical,we sought to improve the understanding of its plant target.Here we solve a 2.3A°resolution crystal structure for Arabidopsis thaliana DHPS that is conjoined to 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase(HPPK),and we reveal a strong structural conservation with bacterial counterparts at the sulfonamide-bindingpocket of DHPS.We demonstrate that asulamand the antibiotic sulfamethoxazole have herbicidal as well as antibacterial activity,andwe explore the structural basis of their potency by modeling these compounds in mitochondrial HPPK/DHPS.Our findings suggest limited opportunity for the rational design of plant selectivity fromasulamand indicate that pharmacokinetic or delivery differences between plants andmicrobesmight be the bestways to safeguard thismode of action.