Identifying the role of MTHFD1L in prostate cancer progression from genetic analysis and experimental validation.

One-carbon metabolism plays a crucial role in tumorigenesis as it supplies the one-carbon units necessary for nucleotide synthesis, epigenetic regulation, and redox metabolism, ensuring the rapid proliferation of cancer cells. However, their roles in prostate cancer progression remain poorly understood. In this study, we investigated the association between genetic variants in the one-carbon metabolism pathway and clinical outcomes in patients receiving androgen deprivation therapy for prostate cancer. The associations of 130 single-nucleotide polymorphisms located within 14 genes involved in the one-carbon metabolism pathway with cancer-specific survival (CSS), overall survival, and progression-free survival were assessed using Cox regression in 630 patients with prostate cancer. Subsequently, functional studies were performed using prostate cancer cell lines. After adjusting for covariates and multiple testing, MTHFD1L rs2073190 was found to be significantly associated with CSS (P = 0.000184). Further pooled analysis of multiple datasets demonstrated that MTHFD1L was upregulated in prostate cancer and increased MTHFD1L expression was positively correlated with tumor aggressiveness and poor patient prognosis. Functionally, MTHFD1L knockdown suppressed prostate cancer cell proliferation and colony formation. RNA sequencing and pathway analysis revealed that differentially expressed genes were predominantly enriched in the cell cycle pathway. In conclusion, genetic variants in MTHFD1L of one-carbon metabolism may serve as promising predictors, and our findings offer valuable insights into the underlying genetic mechanisms of prostate cancer progression.

MTHFD1L confers a poor prognosis and malignant phenotype in esophageal squamous cell carcinoma by activating the ERK5 signaling pathway.

MTHFD1L, a key enzyme of folate metabolism, is seldom reported in cancer. In this study, we investigate the role of MTHFD1L in the tumorigenicity of esophageal squamous cell carcinoma (ESCC). ESCC tissue microarrays (TMAs) containing 177 samples from 109 patients were utilized to evaluate whether MTHFD1L expression, determined using immunohistochemical analysis, is a prognostic indicator for ESCC patients. The function of MTHFD1L in the migration and invasion of ESCC cells was studied with wound healing, Transwell, and three-dimensional spheroid invasion assays in vitro and a lung metastasis mouse model in vivo. The mRNA microarrays and Ingenuity pathway analysis (IPA) were used to explore the downstream of MTHFD1L. Elevated expression of MTHFD1L in ESCC tissues was significantly associated with poor differentiation and prognosis. These phenotypic assays revealed that MTHFD1L significantly promote the viability and metastasis of ESCC cell in vivo and in vitro. Further detailed analyses of the molecular mechanism demonstrated that the ESCC progression driven by MTHFD1L was through up-regulation ERK5 signaling pathways. These findings reveal that MTHFD1L is positively associated with the aggressive phenotype of ESCC by activating ERK5 signaling pathways, suggesting that MTHFD1L is a new biomarker and a potential molecular therapeutic target for ESCC.

Folate Metabolism in Hepatocellular Carcinoma. What Do We Know So Far?

Cancer cells are characterized by accelerated proliferation and an outstanding adaptation of their metabolic pathways to meet energy demands. The folate cycle, also known as folate metabolism or one-carbon metabolism, through enzymatic interconversions, provides metabolites necessary for nucleotide synthesis, methylation, and reduction power, helping to maintain the high rate of proliferation; therefore, the study of this metabolic pathway is of great importance in the study of cancer. Moreover, multiple enzymes involved in this cycle have been implicated in different types of cancer, corroborating the cell's adaptations under this pathology. During the last decade, nonalcoholic fatty liver disease has emerged as the leading etiology related to the rise in the incidence and deaths of hepatocellular carcinoma. Specifically, cholesterol accumulation has been a determinant promoter of tumor formation, with solid evidence that an enriched-cholesterol diet plays a crucial role in accelerating the development of an aggressive subtype of hepatocellular carcinoma compared to other models. In this review, we will discuss the most recent findings to understand the contribution of folate metabolism to cancer cells and tumor microenvironment while creating a link between the dynamics given by cholesterol and methylenetetrahydrofolate dehydrogenase 1-like, a key enzyme of the cycle located in the mitochondrial compartment.

A pro-metastatic tRNA fragment drives Nucleolin oligomerization and stabilization of its bound metabolic mRNAs.

Stress-induced cleavage of transfer RNAs (tRNAs) into tRNA-derived fragments (tRFs) occurs across organisms from yeast to humans; yet, its mechanistic underpinnings and pathological consequences remain poorly defined. Small RNA profiling revealed increased abundance of a cysteine tRNA fragment (5'-tRFCys) during breast cancer metastatic progression. 5'-tRFCys was required for efficient breast cancer metastatic lung colonization and cancer cell survival. We identified Nucleolin as the direct binding partner of 5'-tRFCys. 5'-tRFCys promoted the oligomerization of Nucleolin and its bound metabolic transcripts Mthfd1l and Pafah1b1 into a higher-order transcript stabilizing ribonucleoprotein complex, which protected these transcripts from exonucleolytic degradation. Consistent with this, Mthfd1l and Pafah1b1 mediated pro-metastatic and metabolic effects downstream of 5'-tRFCys-impacting folate, one-carbon, and phosphatidylcholine metabolism. Our findings reveal that a tRF can promote oligomerization of an RNA-binding protein into a transcript stabilizing ribonucleoprotein complex, thereby driving specific metabolic pathways underlying cancer progression.

Activated brown adipose tissue releases exosomes containing mitochondrial methylene tetrahydrofolate dehydrogenase (NADP dependent) 1-like protein (MTHFD1L).

Brown adipose tissue (BAT) is a promising weapon to combat obesity and metabolic disease. BAT is thermogenic and consumes substantial amounts of glucose and fatty acids as fuel for thermogenesis and energy expenditure. To study BAT function in large human longitudinal cohorts, safe and precise detection methodologies are needed. Although regarded a gold standard, the foray of PET-CT into BAT research and clinical applications is limited by its high ionizing radiation doses. Here, we show that brown adipocytes release exosomes in blood plasma that can be utilized to assess BAT activity. In the present study, we investigated circulating protein biomarkers that can accurately and reliably reflect BAT activation triggered by cold exposure, capsinoids ingestion and thyroid hormone excess in humans. We discovered an exosomal protein, methylene tetrahydrofolate dehydrogenase (NADP+ dependent) 1-like (MTHFD1L), to be overexpressed and detectable in plasma for all three modes of BAT activation in human subjects. This mitochondrial protein is packaged as a cargo within multivesicular bodies of the endosomal compartment and secreted as exosomes via exocytosis from activated brown adipocytes into the circulation. To support MTHFD1L as a conserved BAT activation response in other vertebrates, we examined a rodent model and also proved its presence in blood of rats following BAT activation by cold exposure. Plasma concentration of exosomal MTHFD1L correlated with human BAT activity as confirmed by PET-MR in humans and supported by data from rats. Thus, we deduce that MTHFD1L appears to be overexpressed in activated BAT compared to BAT in the basal nonstimulated state.

Circular RNA circ-MTHFD1L induces HR repair to promote gemcitabine resistance via the miR-615-3p/RPN6 axis in pancreatic ductal adenocarcinoma.

BACKGROUND: Chemoresistance of pancreatic cancer is the main reason for the poor treatment effect of pancreatic cancer patients. Exploring chemotherapy resistance-related genes has been a difficult and hot topic of oncology. Numerous studies implicate the key roles of circular RNAs (circRNAs) in the development of pancreatic cancer. However, the regulation of circRNAs in the process of pancreatic ductal adenocarcinoma (PDAC) chemotherapy resistance is not yet fully clear. METHODS: Based on the cross-analysis of the Gene Expression Omnibus (GEO) database and the data of our center, we explored a new molecule, hsa_circ_0078297 (circ-MTHFD1L), related to chemotherapy resistance. QRT-PCR was used to detect the expression of circRNAs, miRNAs, and mRNAs in human PDAC tissues and their matched normal tissues. The interaction between circ-MTHFD1L and miR-615-3p/RPN6 signal axis was confirmed by a series of experiments such as Dual-luciferase reporter assay, fluorescence in situ hybridization (FISH) RNA immunoprecipitation (RIP) assays. RESULTS: Circ-MTHFD1L was significantly increased in PDAC tissues and cells. And in PDAC patients, the higher the expression level of circ-MTHFD1L, the worse the prognosis. Mechanism analysis showed that circ-MTHFD1L, as an endogenous miR-615-3p sponge, upregulates the expression of RPN6, thereby promoting DNA damage repair and exerting its effect on enhancing gemcitabine chemotherapy resistance. More importantly, we also found that Silencing circ-MTHFD1L combined with olaparib can increase the sensitivity of pancreatic cancer to gemcitabine. CONCLUSION: Circ-MTHFD1L maintains PDAC gemcitabine resistance through the miR-615-3p/RPN6 signal axis. Circ-MTHFD1L may be a molecular marker for the effective treatment of PDAC.

Integrative analysis reveals methylenetetrahydrofolate dehydrogenase 1-like as an independent shared diagnostic and prognostic biomarker in five different human cancers.

BACKGROUND: Defects in methylenetetrahydrofolate dehydrogenase 1-like (MTHFD1L) expression have earlier been examined in only a few human cancers. OBJECTIVES: Multi-omics profiling of MTHFD1L as a shared biomarker in distinct subtypes of human cancers. METHODS: In the current study, for the multi-omics analysis of MTHFD1L in 24 major subtypes of human cancers, a comprehensive in silico approach was adopted to mine different open access online databases including UALCAN, Kaplan-Meier (KM) plotter, LOGpc, GEPIA, Human Protein Atlas (HPA), Gene Expression across Normal and Tumor tissue (GENT2), MEXPRESS, cBioportal, STRING, DAVID, TIMER, and Comparative Toxicogenomics Database (CTD). RESULTS: We noticed that the expression of MTHFD1L was significantly higher in all the analyzed 24 subtypes of human cancers as compared with the normal controls. Moreover, MTHDF1L overexpression was also found to be significantly associated with the reduced overall survival (OS) duration of Bladder urothelial cancer (BLCA), Head and neck cancer (HNSC), Kidney renal papillary cell carcinoma (KIRP), Lung adenocarcinoma (LUAD), and Uterine corpus endometrial carcinoma (UCEC). This implies that MTHFD1L plays a significant role in the development and progression of these cancers. We further noticed that MTHFD1L was also overexpressed in BLCA, HNSC, KIRP, LUAD, and UCEC patients of different clinicopathological features. Pathways enrichment analysis revealed the involvement of MTHFD1L-associated genes in five diverse pathways. We also explored few interesting correlations between MTHFD1L expression and its promoter methylation, genetic alterations, CNVs, and between CD8+ T immune cells level. CONCLUSION: In conclusion, our results elucidated that MTHFD1L can serve as a shared diagnostic and prognostic biomarker in BLCA, HNSC, KIRP, LUAD, and UCEC patients of different clinicopathological features.

Melatonin modulates metabolic remodeling in HNSCC by suppressing MTHFD1L-formate axis.

Metabolic remodeling is now widely recognized as a hallmark of cancer, yet its role in head and neck squamous cell carcinoma (HNSCC) remains largely unknown. In this study, metabolomic analysis of melatonin-treated HNSCC cell lines revealed that exogenous melatonin inhibited many important metabolic pathways including folate cycle in HNSCC cells. Methylenetetrahydrofolate dehydrogenase 1 like (MTHFD1L), a metabolic enzyme of the folate cycle regulating the production of formate, was identified as a downstream target of melatonin. MTHFD1L was found to be markedly upregulated in HNSCC, and MTHFD1L overexpression was significantly associated with unfavorable clinical outcome of HNSCC patients. In addition, MTHFD1L promoted HNSCC progression in vitro and in vivo and reversed the oncostatic effects of exogenous melatonin. More importantly, the malignant phenotypes suppressed by knockdown of MTHFD1L or exogenous melatonin could be partially rescued by formate. Furthermore, we found that melatonin inhibited the expression of MTHFD1L in HNSCC cells through the downregulation of cyclic AMP-responsive element-binding protein 1 (CREB1) phosphorylation. Lastly, this novel regulatory axis of melatonin-p-CREB1-MTHFD1L-formate was also verified in HNSCC tissues. Collectively, our findings have demonstrated that MTHFD1L-formate axis promotes HNSCC progression and melatonin inhibits HNSCC progression through CREB1-mediated downregulation of MTHFD1L and formate. These findings have revealed new metabolic mechanisms in HNSCC and may provide novel insights on the therapeutic intervention of HNSCC.

The Incoherent Fluctuation of Folate Pools and Differential Regulation of Folate Enzymes Prioritize Nucleotide Supply in the Zebrafish Model Displaying Folate Deficiency-Induced Microphthalmia and Visual Defects.

OBJECTIVE: Congenital eye diseases are multi-factorial and usually cannot be cured. Therefore, proper preventive strategy and understanding the pathomechanism underlying these diseases become important. Deficiency in folate, a water-soluble vitamin B, has been associated with microphthalmia, a congenital eye disease characterized by abnormally small and malformed eyes. However, the causal-link and the underlying mechanism between folate and microphthalmia remain incompletely understood. METHODS: We examined the eye size, optomotor response, intracellular folate distribution, and the expression of folate-requiring enzymes in zebrafish larvae displaying folate deficiency (FD) and ocular defects. RESULTS: FD caused microphthalmia and impeded visual ability in zebrafish larvae, which were rescued by folate and dNTP supplementation. Cell cycle analysis revealed cell accumulation at S-phase and sub-G1 phase. Decreased cell proliferation and increased apoptosis were found in FD larvae during embryogenesis in a developmental timing-specific manner. Lowered methylenetetrahydrofolate reductase (mthfr) expression and up-regulated methylenetetrahydrofolate dehydrogenase (NADP+-dependent)-1-like (mthfd1L) expression were found in FD larvae. Knocking-down mthfd1L expression worsened FD-induced ocular anomalies; whereas increasing mthfd1L expression provided a protective effect. 5-CH3-THF is the most sensitive folate pool, whose levels were the most significantly reduced in response to FD; whereas 10-CHO-THF levels were less affected. 5-CHO-THF is the most effective folate adduct for rescuing FD-induced microphthalmia and defective visual ability. CONCLUSION: FD impeded nucleotides formation, impaired cell proliferation and differentiation, caused apoptosis and interfered active vitamin A production, contributing to ocular defects. The developmental timing-specific and incoherent fluctuation among folate adducts and increased expression of mthfd1L in response to FD reflect the context-dependent regulation of folate-mediated one-carbon metabolism, endowing the larvae to prioritize the essential biochemical pathways for supporting the continuous growth in response to folate depletion.

Metabotype analysis of Mthfd1l-null mouse embryos using desorption electrospray ionization mass spectrometry imaging.

Mammalian folate-dependent one-carbon (1C) metabolism provides the building blocks essential during development via amino acid interconversion, methyl-donor production, regeneration of redox factors, and de novo purine and thymidylate synthesis. Folate supplementation prevents many neural tube defects (NTDs) that occur during the embryonic process of neurulation. The mechanism by which folate functions during neurulation is not well understood, and not all NTDs are preventable by folate supplementation. Mthfd1l is a mitochondrial 1C metabolism enzyme that produces formate, a 1C donor that fuels biosynthesis and the methyl cycle in the cytoplasm. Homozygous deletion of the Mthfd1l gene in mice (Mthfd1lz/z) causes embryonic lethality, developmental delay, and folate-resistant NTDs. These mice also have defects in cranial mesenchyme formation. In this work, mass spectrometry imaging was used to obtain ion maps of the cranial mesenchyme that identified the spatial distribution and relative abundance of metabolites in wild-type and Mthfd1lz/z embryos. The relative abundances of purine and thymidylate derivatives, as well as amino acids, were diminished in the cranial mesenchyme of Mthfd1lz/z embryos. Loss of Mthfd1l activity in this region also led to abnormal levels of methionine and dysregulated energy metabolism. These alterations in metabolism suggest possible approaches to preventing NTDs in humans.

Integrated bioinformatics analysis identified MTHFD1L as a potential biomarker and correlated with immune infiltrates in hepatocellular carcinoma.

Liver hepatocellular carcinoma (LIHC) is one of the most frequently occurring primary malignant liver tumors and seriously harms people's health in the world. Methylenetetrahydrofolate dehydrogenase 1-like (MTHFD1L) has been shown to be associated with colon cancer cell proliferation, colony formation and invasion. In the present study, a total of 370 LIHC and 51 normal samples data were downloaded from The Cancer Genome Atlas (TCGA) database. Bioinformatics and immunohistochemistry (IHC) analysis showed that MTHFD1L is highly expressed in liver tumors. Correlation analysis suggested the differences of vital status between high- and low-expression MTHFD1L groups of LIHC. Univariate and multivariate Cox proportional hazards regression were performed to identify the relationship between clinical characteristics and overall survival (OS). In addition, to explore whether MTHFD1L has an effect on the immune infiltration of LIHC. The correlation between MTHFD1L expression and 24 immune cells were analyzed by ImmuneCellAI database. Furthermore, we combined three databases CIBERSORT, TIMER and ImmuneCellAI to do a comprehensive validation and determined that dendritic cells (DCs) resting, macrophage M0 and macrophage M2 closely related to the expression of MTHFD1L. The results showed that MTHFD1L was a potential prognostic biomarker for LIHC, and could help to elucidate that how the immune microenvironment promotes liver cancer development.

NAD-dependent methylenetetrahydrofolate dehydrogenase inhibits oral squamous cell carcinoma cell proliferation and promotes apoptosis.

BACKGROUND: NAD-dependent methylenetetrahydrofolate dehydrogenase catalyzes the conversion of 10-formyltetrahydrofolate to formate in embryonic and adult mammalian mitochondria. Methylenetetrahydrofolate dehydrogenase 1-like (MTHFD1L) is a folate cycle enzyme that is involved in the development of various diseases including cancer. However, the specific mechanisms in oral squamous cell carcinoma (OSCC) are unclear. We analyzed the functional routes of MTHFD1L in OSCC cells. METHODS: MTHFD1L expression in OSCC was analyzed using data from The Cancer Genome Atlas (TCGA) database. Then, the levels of mRNA were measured in OSCC and para-tumor oral tissues using Affymetrix microarrays. Additionally, the effects of short hairpin RNA (shRNA)-induced MTHFD1L silencing on the biological behavior of OSCC were assessed in vitro and in vivo, and the potential molecular mechanisms underlying MTHFD1L activity were also investigated. RESULTS: A TCGA database analysis of RNA sequencing revealed that MTHFD1L levels were higher in tumor tissue than in adjacent tissues. Immunohistochemical staining and Kaplan-Meier survival analysis also indicated that MTHFD1L upregulation is associated with a poor prognosis in OSCC. The knockdown of MTHFD1L suppressed cell proliferation, colony formation, and tumorigenesis, while it induced apoptosis in OSCC. Mechanistically, a microarray analysis showed that MTHFD1L suppressed c-MYC and activated p53 signaling by regulating the protein expression of TP53, GADD45A, FAS and JUN. CONCLUSIONS: MTHFD1L may be involved in OSCC progression via the c-MYC gene and p53 signaling and may serve as a novel target and orientation for tumor therapy.

Arbutin suppresses osteosarcoma progression via miR-338-3p/MTHFD1L and inactivation of the AKT/mTOR pathway.

Arbutin, a glycoside extracted from the plant Arctostaphylos uva-ursi, has been previously reported to possess antioxidant, anti-inflammatory and anticancer effects. Here, we investigated whether arbutin affects the proliferation of the cells of the osteosarcoma (OS) cell lines MG-63 and SW1353. Arbutin suppressed OS cell viability in a dose- and time-dependent manner, as shown by Cell Counting Kit-8 assay. Furthermore, arbutin exposure decreased the protein levels of MTHFD1L, CCND1 and phosphorylated-protein kinase B (AKT)/phosphorylated-mammalian target of rapamycin (mTOR). Potential upstream miRNAs of MTHFD1L were predicted using TargetScan, PICTAR5, miRanda and miRWalk. We performed luciferase activity assays to show that miR-338-3p directly targets and negatively regulates the expression of MTHFD1L. Knockdown of miR-338-3p promoted cell invasion, migration and proliferation in arbutin-treated OS cells via MTHFD1L. In summary, our data suggest that arbutin inhibits OS cell proliferation, migration and invasion via miR-338-3p/MTHFD1L and by inactivating the AKT/mTOR pathway.

Influence of SH2B3, MTHFD1L, GGCX, and ITGB3 Gene Polymorphisms on theVariability on Warfarin Dosage Requirements and Susceptibility to CVD in the Jordanian Population.

The purpose of this study was to investigate the effects of the SH2B3, MTHFD1L, GGCX, and ITGB3 gene variants on the efficacy of warfarin treatment and its effects on the risk of cardiovascular disorders in Jordanian patients. The selected genes and their polymorphisms are involved in many Genome-Wide Association Study (GWAS) associated with cardiovascular disease and the variability of warfarin therapy. The current study conducted a genetic association and pharmacogenetics study in (212) Jordanian cardiovascular patients treated with warfarin and (213) healthy controls. DNA extraction and the Mass ARRAY™ system were used to genotype ten selected polymorphisms within four genes (SH2B3, MTHFD1L, GGCX, and ITGB3). This study confirmed a genetic association of MTHFD1L rs6922269 Single Nucleotide Polymorphism (SNP) with warfarin sensitivity during the initial and stabilization phases of treatment. Moreover, this SNP showed significant differences in the initial and maintenance doses of warfarin. This study also found an association between the genetic haplotypes (AGC and GAT) within the SH2B3 gene and responsiveness to warfarin. However, possession of an MTHFD1L rs491552 variant allele was found to affect the outcome measure of the international normalized ratio (INR) during the stabilization phase of warfarin treatment. In contrast, there was no association between all selected SNPs and susceptibility to cardiovascular disorders. This study extends the current understanding of the high variability of the warfarin response, including variability in dose requirements and susceptibility to cardiovascular disease in the Jordanian-Arab population. Other studies on a larger sample and in different ethnic groups could help to better understand the pharmacogenetics of warfarin and its application in personalized medicine.

High expression of folate cycle enzyme MTHFD1L correlates with poor prognosis and increased proliferation and migration in colorectal cancer.

Aims: To investigate the expression and clinical significance of methylenetetrahydrofolate dehydrogenase 1-like (MTHFD1L) in colorectal cancer (CRC) and its effect on CRC cells proliferation and migration. Methods: 59 fresh CRC tissue samples and matched normal tissues, 176 archive CRC tissue samples and 8 CRC cell lines were tested MTHFD1L by western blot and immunohistochemistry, respectively. The relationship between MTHFD1L expression, clinical significance and prognosis was analyzed by chi-square test and survival analysis. MTT assay, plate clonal formation assay and scratch assay were used to verify the effect of MTHFD1L on the proliferation and migration in CRC cell lines. Results: The results showed that the protein level of MTHFD1L in CRC was significantly higher than that in adjacent normal tissues (p<0.01). The expression of MTHFD1L in CRC was positively correlated with the degree of tumor differentiation, TNM classification, tumor invasion, lymph node metastasis, and distant metastasis. Survival analysis showed that CRC patients with high MTHFD1L expression had a lower 5-year survival rate and the expression of MTHFD1L was an independent adverse factor for the CRC prognosis (p<0.05). Down-regulation of MTHFD1L inhibited the proliferation and migration of DLD-1 and HCT116 CRC cell lines. Conclusion: These findings reveal that MTHFD1L is highly expressive in CRC and associated with poor prognosis, and MTHDF1L can increase colorectal cancer cell proliferation and migration. Therefore, MTHFD1L may serve as a predictor and a potential therapeutic target for CRC.

MTHFD1L as a folate cycle enzyme correlates with prognostic outcome and its knockdown impairs cell invasive behaviors in osteosarcoma via mediating the AKT/mTOR pathway.

Osteosarcoma (OS) is the most frequent primary malignancy initially in bone with multiple genomic aberrations. Methylenetetrahydrofolate dehydrogenase 1-like (MTHFD1L) is linked with the progression of diverse tumors. However, its function in OS is not understood completely. The expression pattern and prognostic significance of MTHFD1L in OS tissues were analyzed based on GEO database. The expression level of MTHFD1L in OS cell lines was explored by qRT-PCR. The cell proliferation, colony formation ability, invasion as well as migration in OS cells after MTHFD1L knockdown were determined using cell counting kit 8 (CCK-8) assay, colony formation and transwell methods. GSEA analysis was performed to predict the underlying mechanisms of MTHFD1L in OS development. Furthermore, the western blot was utilized to study the influence of MTHFD1L on AKT/mTOR pathway. Our results indicated that MTHFD1L expression was significantly up-regulated in OS tissues and cells compared with normal tissues and cells. High expression of MTHFD1L could lead to poor prognosis of OS patients. Cell proliferation, colony formation ability, migration and invasion were blocked because of reduced MTHFD1L in vitro. Moreover, cell cycle and AKT/mTOR pathway were all associated with MTHFD1L expression. In conclusion, the findings revealed that MTHFD1L might promote the development of OS via mediating cell cycle and AKT/mTOR pathway, indicating that MTHFD1L might act as a promising therapeutic target for OS treatment.

MTHFD1L-Mediated Redox Homeostasis Promotes Tumor Progression in Tongue Squamous Cell Carcinoma.

Background: Routine changes in cell metabolism can drive tumor development, as the cellular program develops to promote glycolysis and redox homeostasis during tumor progression; however, the associated mechanisms in tongue squamous cell carcinoma (TSCC) remain unclear. Methods: We investigated methylenetetrahydrofolate dehydrogenase 1-like (MTHFD1L) expression, its clinical relevance, redox modification, and molecular mechanisms using TSCC cells and tissues. The anti-tumor effects of MTHFD1L knockdown on TSCC tumorigenesis were evaluated in vitro and in vivo. Kaplan-Meier curves and the log-rank test were used to analyze disease-free survival and overall survival. Results: TSCC patients with high expression levels of MTHFD1L had shorter overall survival (P < 0.05) and disease-free survival (P < 0.05). Knockdown of MTHFD1L reduced nicotinamide adenine dinucleotide phosphate (NADPH) levels and increased reactive oxygen species (ROS), which accelerated cell death under oxidative stress, such as hypoxia or glucose deprivation. Additionally, inhibition of MTHFD1L suppressed TSCC cell growth and delayed the cell cycle, including in xenograft experiments. Conclusions: MTHFD1L confers redox homeostasis and promotes TSCC cell growth, which provides a great opportunity to study tumor metabolism in head and neck cancer. The mTORC1-4EBP1-eIF4E axis may affect the expression of MTHFD1L in TSCC. Inhibition of the expression of MTHFD1L may be an actionable and effective therapeutic target in TSCC.

Deletion of neural tube defect-associated gene Mthfd1l causes reduced cranial mesenchyme density.

BACKGROUND: Periconceptional intake of supplemental folic acid can reduce the incidence of neural tube defects by as much as 70%, but the mechanisms by which folic acid supports cellular processes during neural tube closure are unknown. The mitochondrial 10-formyl-tetrahydrofolate synthetase MTHFD1L catalyzes production of formate, thus generating one-carbon units for cytoplasmic processes. Deletion of Mthfd1l causes embryonic lethality, developmental delay, and neural tube defects in mice. METHODS: To investigate the role of mitochondrial one-carbon metabolism during cranial neural tube closure, we have analyzed cellular morphology and function in neural tissues in Mthfd1l knockout embryos. RESULTS: The head mesenchyme showed significantly lower cellular density in Mthfd1l nullizygous embryos compared to wildtype embryos during the process of neural tube closure. Apoptosis and neural crest cell specification were not affected by deletion of Mthfd1l. Sections from the cranial region of Mthfd1l knockout embryos exhibited decreased cellular proliferation, but only after completion of neural tube closure. Supplementation of pregnant dams with formate improved mesenchymal density and corrected cell proliferation in the nullizygous embryos. CONCLUSIONS: Deletion of Mthfd1l causes decreased density in the cranial mesenchyme and this defect is improved with formate supplementation. This study reveals a mechanistic link between folate-dependent mitochondrially produced formate, head mesenchyme formation and neural tube defects.

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.

Cancer 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.