Methylenetetrahydrofolate Dehydrogenase Research Articles

Modulation of Redox Homeostasis by Inhibition of MTHFD2 in Colorectal Cancer: Mechanisms and Therapeutic Implications.

BackgroundOvercoming oxidative stress is a critical step for tumor progression; however, the underlying mechanisms in colorectal cancer (CRC) remain unclear.MethodsWe investigated nicotinamide adenine dinucleotide (phosphate) (NAD(P))-dependent enzyme methylene tetrahydrofolate dehydrogenase 2 (MTHFD2) expression, clinical relevance, redox modification, and molecular mechanisms using the CRC cells and tissues (n = 462 paired samples). The antitumor effects of MTHFD2 inhibitor LY345899 on CRC tumorigenesis and metastasis were evaluated in vitro and in vivo. Data analysis used Kaplan-Meier, Pearson’s correlation, and Student t test where appropriate. All statistical tests were two-sided.ResultsHere, we report that the patients with high expression of MTHFD2 have a shorter overall survival (HR = 1.62, 95% CI = 1.12 to 2.36, P = .01) and disease-free survival (HR = 1.55, 95% CI = 1.07 to 2.27, P = .02) than patients with low MTHFD2 expression. Suppression of MTHFD2 disturbs NADPH and redox homeostasis and accelerates cell death under oxidative stress, such as hypoxia or anchorage independence (P ≤ .01 for all). Also, genetic or pharmacological inhibition of MTHFD2 suppresses CRC cell growth and lung and peritoneal metastasis in cell-based xenografts (n = 5–8 mice per group). Importantly, LY345899 treatment statistically significantly suppresses tumor growth and decreases the tumor weight in CRC patient-derived xenograft models (n = 10 mice per group, mean [SD] tumor weight of the vehicle-treated group was 1.83 [0.19] mg vs 0.74 [0.30] mg for the LY345899-treated group, P < .001)ConclusionsOur study presents evidence that MTHFD2 confers redox homeostasis and promotes CRC cell growth and metastasis. The folate analog LY345899 as MTHFD2 inhibitor displays therapeutic activity against CRC and warrants further clinical investigation for CRC treatment.

Cancer stem-like properties and gefitinib resistance are dependent on purine synthetic metabolism mediated by the mitochondrial enzyme MTHFD2

Tumor recurrence is attributable to cancer stem-like cells (CSCs), the metabolic mechanisms of which currently remain obscure. Here, we uncovered the critical role of folate-mediated one-carbon (1C) metabolism involving mitochondrial methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) and its downstream purine synthesis pathway. MTHFD2 knockdown greatly reduced tumorigenesis and stem-like properties, which were associated with purine nucleotide deficiency, and caused marked accumulation of 5-aminoimidazole carboxamide ribonucleotide (AICAR)—the final intermediate of the purine synthesis pathway. Lung cancer cells with acquired resistance to the targeted drug gefitinib, caused by elevated expression of components of the β-catenin pathway, exhibited increased stem-like properties and enhanced expression of MTHFD2. MTHFD2 knockdown or treatment with AICAR reduced the stem-like properties and restored gefitinib sensitivity in these gefitinib-resistant cancer cells. Moreover, overexpression of MTHFD2 in gefitinib-sensitive lung cancer cells conferred resistance to gefitinib. Thus, MTHFD2-mediated mitochondrial 1C metabolism appears critical for cancer stem-like properties and resistance to drugs including gefitinib through consumption of AICAR, leading to depletion of the intracellular pool of AICAR. Because CSCs are dependent on MTHFD2, therapies targeting MTHFD2 may eradicate tumors and prevent recurrence.

Drug discovery of anticancer drugs targeting methylenetetrahydrofolate dehydrogenase 2

Many anticancer drugs have serious adverse effects; therefore, it is necessary to target features specific to cancer cells to minimize the effects on healthy cells. Methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) was reported to be specifically enhanced in cancer. We confirmed the validity of MTHFD2 as a drug discovery target using clinical data. In addition, we performed in silico screening to design an anticancer drug specifically targeting MTHFD2. Analysis of the clinical data indicated that MTHFD2 was enhanced in most cancers compared with normal tissues, and affected the prognosis in cancer patients. Candidate compounds for MTHFD2 inhibitors were identified using in silico drug discovery techniques, and the important interactions for MTHFD2 binding were determined. In addition, these candidate compounds decreased levels of MTHFD2 metabolites in cancer cells. The findings of the present study may help to develop anticancer drugs targeting MTHFD2, with a view to minimizing the adverse effects of anticancer drugs.

Exogenous phenylalanine application promotes chilling tolerance in tomato fruits during cold storage by ensuring supply of NADPH for activation of ROS scavenging systems

In this experiment, the mechanisms displayed by exogenous phenylalanine application to confer chilling tolerance in tomato fruits (Lycopersicon esculentum cv. Izmir) during storage at 4 °C for 28 days were studied. Phenylalanine application at 5 mM significantly confers chilling injury tolerance in tomato fruits associated with membrane integrity maintenance reflected by a lower degree of electrolytes leakage and malondialdehyde (MDA) accumulation. Membrane integrity maintenance in tomato fruits in response to exogenous phenylalanine application at 5 mM may arise from lower H2O2 accumulation due to higher activity of reactive oxygen species (ROS) scavenging enzymes superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR), concurrent with higher endogenous lycopene and proline accumulation. In addition, higher phenols and flavonoids accumulation arising from higher phenylalanine ammonia-lyase (PAL) enzyme activity is concurrent with higher ascorbic acid (AA) accumulation giving rise to higher DPPH scavenging capacity, which may be vital for the maintenance of membrane integrity in tomato fruits treated with exogenous phenylalanine. Ensuring supply of reducing power NADPH by triggering of folates pathway demonstrated by higher methylenetetrahydrofolate dehydrogenase (MTHFD) enzyme activity may be responsible for activation of ROS scavenging systems in tomato fruits in response to exogenous phenylalanine application, contributing to membrane integrity maintenance. Accordingly, exogenous phenylalanine application may serve as a safe promising procedure to confer chilling tolerance in tomato fruits during cold storage.

Methylenetetrahydrofolate Dehydrogenase 1 (MTHFD1) is Underexpressed in Clear Cell Renal Cell Carcinoma Tissue and Transfection and Overexpression in Caki-1 Cells Inhibits Cell Proliferation and Increases Apoptosis.

BackgroundThe aims of this study were to investigate the expression of methylenetetrahydrofolate dehydrogenase 1 (MTHFD1) in human tissue containing clear cell renal cell carcinoma (CCRCC) compared with normal renal tissue, and the effects of upregulating the expression of MTHFD1 in the human CCRCC cell line, Caki-1.Material/MethodsTumor and adjacent normal renal tissue were obtained from 44 patients who underwent radical nephrectomy for CCRCC. Caki-1 human CCRCC cells were divided into the control group, the empty vector (EV) group, and the plasmid-treated group that overexpressed MTHFD1. MTHFD1 mRNA and protein levels were measured by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot, respectively. The cell counting kit-8 (CCK-8) assay measured cell viability. Flow cytometry evaluated apoptosis and the cell cycle. Western blot measured the protein levels of MTHFD1, Bax, Bcl-2, Akt, p53, and cyclin D1, and qRT-PCR determined the gene expression profiles.ResultsMTHFD1 mRNA and protein levels in CCRCC tumor tissues were significantly lower compared with adjacent normal renal tissue. MTHFD1 over-expression in Caki-1 cells inhibited cell proliferation, arrested cells in the G1 phase, increased cell apoptosis, and upregulated gene and protein expression of Bax/Bcl-2 and p53, and inhibited p-Akt, and cyclin D1.ConclusionsMTHFD1 was underexpressed in CCRCC tissue when compared with normal renal tissue. MTHFD1 transfection of human CCRCC Caki-1 cells in vitro inhibited cell proliferation and promoted apoptosis, associated with reduced expression of cyclin D1, reduced Akt phosphorylation, and increased expression of Bax/Bcl-2 and p53.

Methylenetetrahydrofolate Dehydrogenase 1 Silencing Expedites the Apoptosis of Non-Small Cell Lung Cancer Cells via Modulating DNA Methylation.

BackgroundNon-small cell lung cancer (NSCLC) accounts for about 85% of all types of lung cancer. Methylenetetrahydrofolate dehydrogenase 1 (MTHFD1) is involved in DNA methylation, and DNA methylation is related to tumorigenesis. The role of MTHFD1 in NSCLC was examined in our study.Material/MethodsThe correlation between the expression of MTHFD1 and the clinicopathological features of patients diagnosed with lung cancer was investigated using the chi-square test. The viability and apoptosis of NCI-H1299 cells was respectively detected using cell counting kit-8 and flow cytometry assays. The expression levels of MTHFD1, apoptosis-related factors and DNA methyltransferase-related factors were assessed by quantitative real-time PCR (qRT-PCR) and western blot assays.ResultsWe found that MTHFD1 expression in the tumor tissues and cells was higher than that of adjacent normal tissues and cells. The survival time of patients with high MTHFD1 expression was shorter than those with low MTHFD1 expression. The expression level of MTHFD1 was related to tumor size, TNM stage, histologic grade, and metastasis, but not linked to gender and age. Besides, si-MTHFD1 significantly decreased the viability of cells in a time-dependent manner, and increased cell apoptosis. When cells were transfected with MTHFD1-siRNA, the levels of surviving and B-cell lymphoma-2 (Bcl-2) were attenuated, while p53 and Bcl-2 associated X protein (Bax) levels were enhanced. Moreover, si-MTHFD1 markedly downregulated the expression levels of DNA methyltransferase 1 (DNMT1), DNMT3a, and DNMT3b.ConclusionsCollectively, our results proved that MTHFD1 silencing obviously reduced the proliferation and enhanced the apoptosis of NSCLC via suppressing DNA methylation.

Overexpression of Methylenetetrahydrofolate Dehydrogenase 1 (MTHFD1L) in Colorectal Cancer: A Potential Therapeutic Target

Overexpression of Methylenetetrahydrofolate Dehydrogenase 1 (MTHFD1L) in Colorectal Cancer: A Potential Therapeutic Target

MTHFD1 promoter hypermethylation increases the risk of hypertension

ABSTRACTObjectives: Methylenetetrahydrofolate dehydrogenase 1 (MTHFD1) plays an essential role in folate-mediated one-carbon metabolism which determines both homocysteine remethylation and de novo thymidylate biosynthesis. Hyperhomocysteinemia is positively associated with essential hypertension. This study aimed to investigate the association of MTHFD1 promoter methylation with essential hypertension.Methods: Using the quantitative methylation-specific polymerase chain reaction (qMSP), the levels of MTHFD1 promoter methylation in 243 essential hypertension patients, 218 age- and gender-matched healthy controls. The relative changes in serum MTHFD1 promoter methylation were analyzed using the 2−ΔΔCt method. The percent of methylated reference (PMR) of MTHFD1 was used to evaluate the MTHFD1 promoter methylation levels.Results: In our current study, the MTHFD1 promoter methylation of hypertensive patients were both higher than the healthy control group (median PMR were 8.97% and 5.69%, respectively, all p < 0.001). Multivariable analysis showed MTHFD1 promoter hypermethylation increase the risk of essential hypertension (OR, 1.336; 95%CI, 1.235–1.446; p < 0.001). The area under the curve (AUC) of MTHFD1 promoter methylation was 0.739 in total patients with essential hypertension.Conclusions: MTHFD1 promoter hypermethylation was a potential biomarker for the diagnosis of essential hypertension.

Abstract 168: Cancer stem-like properties and drug resistance are dependent on purine synthetic metabolism mediated by the mitochondrial enzyme MTHFD2

Abstract Tumor recurrence is attributable to cancer stem-like cells (CSCs), the metabolic mechanisms of which currently remain obscure. Here, we uncovered the critical role of folate-mediated one-carbon (1C) metabolism involving mitochondrial methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) and its downstream purine synthesis pathway. MTHFD2 knockdown greatly reduced tumorigenesis and stem-like properties, which were associated with purine nucleotide deficiency, and caused marked accumulation of 5-aminoimidazole carboxamide ribonucleotide (AICAR)—the final intermediate of the purine synthesis pathway. Lung cancer cells with acquired resistance to the targeted drug gefitinib exhibited increased stem-like properties and enhanced expression of MTHFD2. MTHFD2 knockdown or treatment with AICAR reduced the stem-like properties and restored gefitinib sensitivity in gefitinib-resistant cancer cells. Thus, MTHFD2-mediated mitochondrial 1C metabolism appears critical for cancer stem-like properties and resistance to drugs including gefitinib through consumption of AICAR, leading to depletion of the intracellular pool of AICAR. Because CSCs are dependent on MTHFD2, therapies targeting MTHFD2 may eradicate tumors and prevent recurrence. Citation Format: Noriko Gotoh, Tatsunori Nishimura, Asuka Nakata, Shin-ichi Horike, Susumu Kohno, Chiaki Takahashi, Tomoyoshi Soga, Arinobu Tojo. Cancer stem-like properties and drug resistance are dependent on purine synthetic metabolism mediated by the mitochondrial enzyme MTHFD2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 168.

Abstract 3981: Enhancement of the anticancer activity of methylenetetrahydrofolate dehydrogenase knockdown by folate depletion with carboxypeptidase G2

Abstract The mitochondrial folate enzyme, methylene tetrahydrofolate dehydrogenase (MTHFD2), is a promising anticancer target because 1) it is required for the generation of one-carbon units required for purine synthesis and generation of NADH/NADPH necessary for protection from ROS in the mitochondria; 2) it is markedly distinct from the cytoplasmic MTHFD1 enzyme with respect to location, catalytic activity and cofactors; 3) it is expressed at low levels in proliferating normal cells; 4) in contrast, it is highly expressed in a variety of rapidly proliferating malignant tumors; 5) knockdown (KD) of MTHFD2 has been shown to inhibit proliferation in a subset of tumor cells in vitro; and 6) MTHFD2 KD is predicted to have metabolic consequences (glycine auxotrophy, folate deficiency) that could be exploited for combination therapy. In this study we tested the hypotheses that downregulation of MTHFD2 will result in relative folate deficiency, which can be exploited by using a folate-depleting enzyme, carboxypeptidase G2 (CPG2), to enhance tumor cell kill. CPG2 is approved by the FDA for the treatment of methotrexate overdose in patients. It acts to inactivate MTX or naturally occurring folates by hydrolyzing the terminal glutamate from folates and MTX, generating a pteroate and glutamate. As pteroates cannot be used to resynthesize folates, or MTX, this treatment depletes cells from MTX or folates. The combination of CPG2 in cell lines, MCF7 and T47D with MTHFD2 KD, was done and the actual increase in growth inhibition showed enhanced antitumor effects, indicating that when effective inhibitors of MTHFD2 are available, this combination may have widespread clinical usefulness, especially in rapidly proliferating tumors that express high levels of MTHFD2. Citation Format: Gulam M. Rather, John E. Kerrigan, Kathleen W. Scotto, Joseph R. Bertino. Enhancement of the anticancer activity of methylenetetrahydrofolate dehydrogenase knockdown by folate depletion with carboxypeptidase G2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3981.

Low Dietary Folate Interacts with MTHFD1 Synthetase Deficiency in Mice, a Model for the R653Q Variant, to Increase Incidence of Developmental Delays and Defects

BackgroundSuboptimal folate intake, a risk factor for birth defects, is common even in areas with folate fortification. A polymorphism in methylenetetrahydrofolate dehydrogenase 1 (MTHFD1), R653Q (MTHFD1 c.1958 G > A), has also been associated with increased birth defect risk, likely through reduced purine synthesis. ObjectiveWe aimed to determine if the interaction of MTHFD1 synthetase deficiency and low folate intake increases developmental abnormalities in a mouse model for MTHFD1 R653Q. MethodsFemale Mthfd1S+/+ and Mthfd1S+/− mice were fed control or low-folate diets (2 and 0.3 mg folic acid/kg diet, respectively) before mating and during pregnancy. Embryos and placentas were examined for anomalies at embryonic day 10.5. Maternal 1-carbon metabolites were measured in plasma and liver. ResultsDelays and defects doubled in litters of Mthfd1S+/− females fed low-folate diets compared to wild-type females fed either diet, or Mthfd1S+/− females fed control diets [P values (defects): diet 0.003, maternal genotype 0.012, diet × maternal genotype 0.014]. These adverse outcomes were associated with placental dysmorphology. Intrauterine growth restriction was increased by embryonic Mthfd1S+/− genotype, folate deficiency, and interaction of maternal Mthfd1S+/− genotype with folate deficiency (P values: embryonic genotype 0.045, diet 0.0081, diet × maternal genotype 0.0019). Despite a 50% increase in methylenetetrahydrofolate reductase expression in low-folate maternal liver (P diet = 0.0007), methyltetrahydrofolate concentration decreased 70% (P diet <0.0001) and homocysteine concentration doubled in plasma (P diet = 0.0001); S-adenosylmethionine decreased 40% and S-adenosylhomocysteine increased 20% in low-folate maternal liver (P diet = 0.002 and 0.0002, respectively). ConclusionMTHFD1 synthetase-deficient mice are more sensitive to low folate intake than wild-type mice during pregnancy. Reduced purine synthesis due to synthetase deficiency and altered methylation potential due to low folate may increase pregnancy complications. Further studies and individualized intake recommendations may be required for women homozygous for the MTHFD1 R653Q variant.

Deletion of the neural tube defect–associated gene Mthfd1l disrupts one-carbon and central energy metabolism in mouse embryos

One-carbon (1C) metabolism is a universal folate-dependent pathway essential for de novo purine and thymidylate synthesis, amino acid interconversion, universal methyl-donor production, and regeneration of redox cofactors. Homozygous deletion of the 1C pathway gene Mthfd1l encoding methylenetetrahydrofolate dehydrogenase (NADP+-dependent) 1-like, which catalyzes mitochondrial formate production from 10-formyltetrahydrofolate, results in 100% penetrant embryonic neural tube defects (NTDs), underscoring the central role of mitochondrially derived formate in embryonic development and providing a mechanistic link between folate and NTDs. However, the specific metabolic processes that are perturbed by Mthfd1l deletion are not known. Here, we performed untargeted metabolomics on whole Mthfd1l-null and wildtype mouse embryos in combination with isotope tracer analysis in mouse embryonic fibroblast (MEF) cell lines to identify Mthfd1l deletion-induced disruptions in 1C metabolism, glycolysis, and the TCA cycle. We found that maternal formate supplementation largely corrects these disruptions in Mthfd1l-null embryos. Serine tracer experiments revealed that Mthfd1l-null MEFs have altered methionine synthesis, indicating that Mthfd1l deletion impairs the methyl cycle. Supplementation of Mthfd1l-null MEFs with formate, hypoxanthine, or combined hypoxanthine and thymidine restored their growth to wildtype levels. Thymidine addition alone was ineffective, suggesting a purine synthesis defect in Mthfd1l-null MEFs. Tracer experiments also revealed lower proportions of labeled hypoxanthine and inosine monophosphate in Mthfd1l-null than in wildtype MEFs, suggesting that Mthfd1l deletion results in increased reliance on the purine salvage pathway. These results indicate that disruptions of mitochondrial 1C metabolism have wide-ranging consequences for many metabolic processes, including those that may not directly interact with 1C metabolism.

Origin of clear cell carcinoma: nature or nurture?

A rare but serious complication of endometriosis is the development of carcinoma, and clear cell and endometrioid carcinomas of the ovary are the two most common malignancies which arise from endometriosis. They are distinct diseases, characterized by unique morphologies, immunohistochemical profiles, and responses to treatment. However, both arise in endometriosis and can share common mutations. The overlapping mutational profiles of clear cell and endometrioid carcinomas suggest that their varied histologies may be due to a different cell of origin which gives rise to each type of cancer. Cochrane and colleagues address this question in a recent article in this journal. They show that a marker of ovarian clear cell carcinoma, cystathionine gamma lyase, is expressed in ciliated cells. Similarly, they show that markers of secretory cells (estrogen receptor and methylenetetrahydrofolate dehydrogenase 1) are expressed in ovarian endometrioid carcinoma. Taken together, they suggest that endometrioid and clear cell carcinomas arise from cells related to secretory and ciliated cells, respectively. We discuss Cochrane et al's work in the context of other efforts to determine the cell of origin of gynecological malignancies, with an emphasis on recent developments and challenges unique to the area. These limitations complicate our interpretation of tumor differentiation; does it reflect nature imposed by a specific cell of origin or nurture, by either mutation(s) or environment? Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

MTHFD2 Overexpression Predicts Poor Prognosis in Renal Cell Carcinoma and is Associated with Cell Proliferation and Vimentin-Modulated Migration and Invasion

Background/Aims: To investigate the role of methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) in the clinical prognosis and cell biology of renal cell carcinoma (RCC). Methods: A total of 137 RCC tissues were evaluated by immunohistochemistry. The relationship between MTHFD2 overexpression and clinical parameters and vimentin expression was assessed. Kaplan-Meier curves and the log-rank test were applied for survival analysis according to MTHFD2 and vimentin expression in RCC tissues. The expression of MTHFD2 mRNA and protein was examined by quantitative reverse transcription PCR and western blotting, respectively. To determine further the biological activity of MTHFD2 in RCC, 786-O cells were transfected with short hairpin RNA specifically targeting MTHFD2 (shMTHFD2) with or without tumor necrosis factor (TNF)-α stimulation. Cell proliferation, cell migration and invasion and drug sensitivity were subsequently assessed using Cell Counting Kit-8, wound healing, and Transwell assays. Results: Immunohistochemical analysis demonstrated that both MTHFD2 and vimentin overexpression was positively associated with clinical staging, pathological grade, and poor overall survival (all P < 0.05). MTHFD2 expression was closely correlated with vimentin overexpression in RCC (r = 0.402, P < 0.001). After knocking down MTHFD2 expression in 786-O cells, decreased cell proliferation, migration, and invasion were observed and accompanied by the reduced expression of vimentin. The effects of MTHFD2 down-regulation could be partially restrained by TNF-α treatment. Vimentin expression and cell migration and invasion, but not cell proliferation, were reversed by TNF-α stimulation. Furthermore, treatment of 786-O cells with shMTHFD2 increased their sensitivity to chemotherapy drugs. Conclusion: The current results demonstrated that MTHFD2 was overexpressed in RCC and associated with poor clinical characteristics, vimentin expression, and cellular features connected to malignant disease, thus, implicating MTHFD2 as a potential target for RCC therapy.

The role of mitochondrial folate enzyme MTHFD1L in esophageal squamous cell carcinoma

Objective: The lack of novel therapeutic targets poses the major challenge to prolong survival and improve the quality of life for esophageal squamous cell carcinoma (ESCC). Methylenetetrahydrofolate dehydrogenase 1-like (MTHFD1L) plays critical roles in folate cycle maintenance. However, little information is available concerning the role of MTHFD1L in cancer cells, and no studies have addressed such issues in esophageal cancer.Materials and method: Surgical cancer and adjacent normal esophageal tissues were obtained from patients with esophagectomy and esophagogastrostomy for ESCC. Western blot, immunohistochemistry and Quantitative RT-PCR were performed to evaluate protein and RNA expression levels of MTHFD1L. Knockdown of MTHFD1L expression was achieved by using short hairpin RNA. The effects of MTHFD1L silencing on ESCC cell proliferation and apoptosis were assessed by the MTT assay, Celigo assays, Annexin V FACS assay and Caspase-3/7 array in vitro.Results: Twenty-three paired cancer and adjacent normal esophageal tissues from patients with ESCC were included in this study. MTHFD1L protein and RNA expression levels were significantly upregulated in ESCC tissue as compared with normal tissue. High expression of MTHFD1 was also detected in two esophageal cancer cell lines (TE-1 and EC109). Knockdown of MTHFD1L expression inhibited the proliferation of TE-1 cells, and the apoptosis was distinctly increased following shMTHFD1L infection.Conclusions: Our preliminary study highlighted for the first time that MTHFD1L might be involved in the development of ESCC, which may provide a new potential tumor-specific therapeutic targeting for anti-folate agents.

The folate cycle is a new metabolic weakness of cancer

ABSTRACTCancer cells harness nutrients to support its rapid proliferation through metabolic reprogramming. Our report identified folate cycle as a metabolic target in hepatocellular carcinoma. Folate cycle stagnation via inhibition of its mitochondrial folate enzyme methylenetetrahydrofolate dehydrogenase 1-like (MTHFD1L) greatly induced oxidative stress improving HCC cells' response to sorafenib.

Dihydrofolate Reductase/Thymidylate Synthase Fine-Tunes the Folate Status and Controls Redox Homeostasis in Plants.

Folates (B9 vitamins) are essential cofactors in one-carbon metabolism. Since C1 transfer reactions are involved in synthesis of nucleic acids, proteins, lipids, and other biomolecules, as well as in epigenetic control, folates are vital for all living organisms. This work presents a complete study of a plant DHFR-TS (dihydrofolate reductase-thymidylate synthase) gene family that implements the penultimate step in folate biosynthesis. We demonstrate that one of the DHFR-TS isoforms (DHFR-TS3) operates as an inhibitor of its two homologs, thus regulating DHFR and TS activities and, as a consequence, folate abundance. In addition, a novel function of folate metabolism in plants is proposed, i.e., maintenance of the redox balance by contributing to NADPH production through the reaction catalyzed by methylenetetrahydrofolate dehydrogenase, thus allowing plants to cope with oxidative stress.

MiR-92a Inhibits Proliferation and Induces Apoptosis by Regulating Methylenetetrahydrofolate Dehydrogenase 2 (MTHFD2) Expression in Acute Myeloid Leukemia.

Aberrant expression of microRNA-92a (miR-92a) has been investigated in various cancers. However, the function and mechanism of miR-92a in acute myeloid leukemia (AML) remain to be elucidated. Our data showed that miR-92a was evidently downregulated and methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) was remarkably upregulated in AML cell lines HL-60 and THP-1. Dual luciferase reporter assay revealed that MTHFD2 was a direct target of miR-92a. Gain- and loss-of-function analysis demonstrated that MTHFD2 knockdown or miR-92a overexpression notably inhibited proliferation and promoted apoptosis of AML cell lines. Restoration of MTHFD2 expression reversed proliferation inhibition and apoptosis induction of AML cells triggered by miR-92a. Moreover, an implanted tumor model in mice indicated that miR-92a overexpression dramatically decreased tumor growth and MTHFD2 expression in vivo. Taken together, our results suggest that miR-92a inhibits proliferation and induces apoptosis by directly regulating MTHFD2 expression in AML. miR-92a may act as a tumor suppressor in AML, providing a promising therapeutic target for AML patients.

Computational analysis for the determination of deleterious nsSNPs in human MTHFD1 gene

Single nucleotide polymorphisms (SNPs) are the most common genetic polymorphisms and play a major role in many inherited diseases. Methylenetetrahydrofolate dehydrogenase 1 (MTHFD1) is one of the enzymes involved in folate metabolism. In the present study, the functional and structural consequences of nsSNPs of human MTHFD1 gene was analyzed using various computational tools like SIFT, PolyPhen2, PANTHER, PROVEAN, SNAP2, nsSNPAnalyzer, PhD-SNP, SNPs&GO, I-Mutant, MuPro, ConSurf, InterPro, NCBI Conserved Domain Search tool, ModPred, SPARKS-X, RAMPAGE, FT Site and PyMol. Out of 327 nsSNPs form human MTHFD1 gene, total 45 SNPs were predicted as functionally most significant SNPs, among which 17 were highly conserved and functional, 17 were highly conserved and structural residues. Among 45 most significant SNPs, 15 were predicted to be involved in post translational modifications. The p.Gly165Arg may interfere in homodimer interface formation. The p.Asn439Lys and p.Asp445Asn may interfere in binding interactions of MTHFD1 protein with cesium cation and potassium. The two SNPs (p.Asp562Gly and p.Gly637Cys) might interfere in interactions of MTHFD1 with ligand.

Deletion of one allele of Mthfd1 (methylenetetrahydrofolate dehydrogenase 1) impairs learning in mice.

The MTHFD1 gene encodes for methylenetetrahydrofolate dehydrogenase 1, an enzyme that has an important role in folate-mediated one-carbon metabolism. In people, a single nucleotide polymorphism of this gene (1958G>A; rs2236225) is associated with increased risk for bipolar disorder and schizophrenia, neural tube and other birth defects. Mice homozygous for a loss of Mthfd1 via a gene-trap mutation are not viable, and heterozygotes, though they appear healthy, have metabolic imbalances in the folate- and choline-mediated 1-carbon metabolic pathways. In this study, we evaluated cognitive function in Mthfd1gt/+ male and female mice using a behavioral battery composed of eight different tests. We found that these mice display impaired cue-conditioned learning, while other behaviors remain intact.