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Liu J, Hong S, Yang J, Zhang X, Wang Y, Wang H, Peng J, Hong L. Targeting purine metabolism in ovarian cancer. J Ovarian Res 2022; 15:93. [PMID: 35964092 PMCID: PMC9375293 DOI: 10.1186/s13048-022-01022-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 07/17/2022] [Indexed: 11/10/2022] Open
Abstract
Purine, an abundant substrate in organisms, is a critical raw material for cell proliferation and an important factor for immune regulation. The purine de novo pathway and salvage pathway are tightly regulated by multiple enzymes, and dysfunction in these enzymes leads to excessive cell proliferation and immune imbalance that result in tumor progression. Maintaining the homeostasis of purine pools is an effective way to control cell growth and tumor evolution, and exploiting purine metabolism to suppress tumors suggests interesting directions for future research. In this review, we describe the process of purine metabolism and summarize the role and potential therapeutic effects of the major purine-metabolizing enzymes in ovarian cancer, including CD39, CD73, adenosine deaminase, adenylate kinase, hypoxanthine guanine phosphoribosyltransferase, inosine monophosphate dehydrogenase, purine nucleoside phosphorylase, dihydrofolate reductase and 5,10-methylenetetrahydrofolate reductase. Purinergic signaling is also described. We then provide an overview of the application of purine antimetabolites, comprising 6-thioguanine, 6-mercaptopurine, methotrexate, fludarabine and clopidogrel. Finally, we discuss the current challenges and future opportunities for targeting purine metabolism in the treatment-relevant cellular mechanisms of ovarian cancer.
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Affiliation(s)
- Jingchun Liu
- Department of Obstetrics and Gynecology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Shasha Hong
- Department of Obstetrics and Gynecology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Jiang Yang
- Department of Obstetrics and Gynecology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Xiaoyi Zhang
- Department of Obstetrics and Gynecology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Ying Wang
- Department of Obstetrics and Gynecology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Haoyu Wang
- Department of Obstetrics and Gynecology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Jiaxin Peng
- Department of Obstetrics and Gynecology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Li Hong
- Department of Obstetrics and Gynecology, Renmin Hospital of Wuhan University, Wuhan, China.
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Zou XL, Yao TX, Deng L, Chen L, Li Y, Zhang L. A systematic review and meta-analysis expounding the relationship between methylene tetrahydrofolate reductase gene polymorphism and the risk of intracerebral hemorrhage among populations. Front Genet 2022; 13:829672. [PMID: 35991566 PMCID: PMC9382188 DOI: 10.3389/fgene.2022.829672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 07/04/2022] [Indexed: 12/03/2022] Open
Abstract
Background: The relationship between methylenetetrahydrofolate reductase (MTHFR) gene C677T and A1298C polymorphism with the risk of intracerebral hemorrhage (ICH) has remained to be controversial in recent years. This meta-analysis is aimed to confirm the association of these. Methods: Systematically searching the related studies from the PubMed, Embase, Cochrane Library, China national knowledge internet database from 1 January 1990 to 1 June 2022. The odd ratio (ORs) and 95% confidence interval (CIs) of gene-disease correlation in various gene models were calculated by fixed or random effect model of meta-analysis. We included 20 case-control studies in this meta-analysis with a total of 1,989 ICH patients and 4,032 health controls originated from Asian, Caucasian, and African populations. Results: The statistical analysis demonstrated the association of MTHFR C677T gene polymorphism with ICH in allele model [ORT VS. C = 1.20 (95%CI: 1.06–1.36)]; homozygote model [OR TT VS. CC = 1.50 (95%CI: 1.20–1.88)]; dominant model [OR CT+ TT VS. CC = 1.23 (95%CI: 1.03–1.48)] and recessive model [ORTT VS. CT+CC = 1.37 (95%CI: 1.17–1.60)]. Besides, we also found the relationship of MTHFR C677T gene polymorphism with Asian in four comparison model (ORT VS. C = 1.19.95%CI:1.09–1.37, ORTT VS. CC = 1.46.95%CI: 1.15–1.85, OR CT+ TT VS. CC = 1.25.95%CI: 1.01–1.54, ORTT VS. CT+CC = 1.34.95%CI: 1.54–1.17) and Caucasian in four comparison model (ORT VS. C = 1.90.95%CI: 1.22–2.97, ORTT VS. CC = 2.67.95%CI: 1.42–5.00, OR CT+ TT VS. CC = 1.56.95%CI: 1.05–2.32, ORTT VS. CT+CC = 2.25.95%CI: 1.46–4.00). But no statistically significant correlation between A1298C polymorphism and the occurrence of ICH was detected in four studies. Conclusion: MTHFR C677T gene polymorphism increases the risk of ICH in Asian and Caucasian populations but has no impact on the incidence in African communities. More importantly, the risk of ICH increases in TT genotype individuals in comparison to CT and CC genotype individuals in Asian and Caucasian populations.
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Affiliation(s)
- Xue-Lun Zou
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- Multi-Modal Monitoring Technology for Severe Cerebrovascular Disease of Human Engineering Research Center, Xiangya Hospital, Central South University, Changsha, China
| | - Tian-Xing Yao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Lu Deng
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Lei Chen
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Ye Li
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Le Zhang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- Multi-Modal Monitoring Technology for Severe Cerebrovascular Disease of Human Engineering Research Center, Xiangya Hospital, Central South University, Changsha, China
- *Correspondence: Le Zhang,
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Kumar A, Sharma R, Misra S, Nath M, Kumar P. Relationship between methylenetetrahydrofolate reductase (MTHFR) gene (A1298C) polymorphism with the risk of stroke: A systematic review and meta-analysis. Neurol Res 2020; 42:913-922. [PMID: 32727306 DOI: 10.1080/01616412.2020.1798107] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Studies on relationship between methylenetetrahydrofolate reductase gene (MTHFR) gene A1298C polymorphism with the risk of ischemic as well as hemorrhagic stroke have shown discordant results. Present meta-analysis was aimed to clarify the relationship between MTHFR gene A1298C polymorphism with risk of stroke. A comprehensive literature search for all published articles was performed in electronic database including PubMed, EMbase, Cochrane Library, Trip Databases, Worldwide Science, CINAHL, and Google Scholar up to 31st December 2019. Pooled odds ratio (ORs) with 95% confidence interval (CIs) under dominant, recessive, and allelic models was calculated. Sensitivity analysis was also performed to detect the heterogeneity. In our meta-analysis, a total of 20 studies with 19 case control studies involving 2871 ischemic stroke (IS) cases and 3984 controls and 3 studies with 201 hemorrhagic stroke cases and 1349 controls were included. Our findings suggest that there was a significant relationship between MTHFR gene A1298C gene polymorphism with risk of ischemic stroke (dominant model: OR = 1.32, 95% CI = 1.06-1.66, recessive model: OR = 1.45, 95% CI = 1.06-1.99 and allelic model: OR = 1.35, 95% CI = 1.00-1.84, respectively). However, no significant relationship between MTHFR gene A1298C gene polymorphism with the risk of hemorrhagic stroke. Findings of this meta-analysis concludes that MTHFR gene A1298 C polymorphism could be capable of increasing stroke susceptibility in Asian, but not in Caucasian population. Genotyping of MTHFR gene A1298C polymorphism may be used as a predictor for the occurrence of ischemic stroke.
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Affiliation(s)
- Amit Kumar
- Department of Pediatrics, Army Hospital Research and Referral , New Delhi, India
| | - Rakhee Sharma
- Department of Pediatrics, Army Hospital Research and Referral , New Delhi, India
| | - Shubham Misra
- Department of Neurology, All India Institute of Medical Sciences , New Delhi, India
| | - Manabesh Nath
- Department of Neurology, All India Institute of Medical Sciences , New Delhi, India
| | - Pradeep Kumar
- Department of Neurology, All India Institute of Medical Sciences , New Delhi, India
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Allam MM, El‐Zawawy HT, Barakat SS, Ahmed SM, Saleh RNM. A hidden cause of infertility in hypothyroid patients. Clin Case Rep 2020; 8:374-378. [PMID: 32128192 PMCID: PMC7044389 DOI: 10.1002/ccr3.2654] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 12/04/2019] [Accepted: 12/14/2019] [Indexed: 12/18/2022] Open
Abstract
Methylene tetrahydrofolate reductase (MTHFR) gene mutations could be the cause of infertility in hypothyroid patients. Hence, it is worthy to screen for MTHFR gene mutations in infertile hypothyroid females and their partners if infertility persists after optimizing thyroid function.
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Affiliation(s)
- Magdy Mohamed Allam
- Internal Medicine Department, Endocrinology UnitAlexandria University Student Hospital (AUSH)AlexandriaEgypt
| | | | - Sherine Samir Barakat
- Internal Medicine DepartmentHaematology UnitAlexandria University Student Hospital (AUSH)AlexandriaEgypt
| | - Soha Magdy Ahmed
- Internal Medicine Department, Endocrinology UnitAlexandria University Student Hospital (AUSH)AlexandriaEgypt
| | - Rasha Noureldin M. Saleh
- Clinical Pathology DepartmentFaculty of MedicineAlexandria UniversityAlexandriaEgypt
- Norwich Medical SchoolUniversity of East AngliaNorwichUK
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Nasri K, Midani F, Kallel A, Ben Jemaa N, Aloui M, Boulares M, Lassoued M, Ben Halima M, Ben Wafi S, Soussi M, Mahjoubi I, Baara A, Ben Fradj MK, Omar S, Feki M, Jemaa R, Gaigi SS, Marrakchi R. Association of MTHFR C677T, MTHFR A1298C, and MTRR A66G Polymorphisms with Neural Tube Defects in Tunisian Parents. Pathobiology 2019; 86:190-200. [PMID: 31238314 DOI: 10.1159/000499498] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 03/11/2019] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE This study aims to investigate the association of 5,10-methylenetetrahydrofolate reductase (MTHFR C677T and A1298C) and methionine synthase reductase (MTRR A66G) gene polymorphisms with neural tube defects (NTDs) in a Tunisian population. METHODS Genotyping was performed by polymerase chain reaction with restriction fragment length polymorphisms (PCR-RFLPs) using the restriction enzymes. Allele and genotype frequencies were compared between mothers and fathers of fetuses with NTDs with matched controls based on an association analysis using SPSS software. RESULTS MTHFR (C677T, A1298C) and MTRR A66G polymorphisms were found to be protector factors for NTD fetuses in the mother group. In addition, a combination of the three wild-type alleles C677/A1298/A66 has increased four-fold the incidence of NTDs (p = 0.004, OR = 3.96, 95% CI: 1.53-10.23). In the father group, MTHFR C677T was a risk factor for NTDs. However, no association was found between MTHFR A1298C, MTRR A66G, and the occurrence of this anomaly. The analysis of MTHFR C677T and MTRR A66G polymorphisms has demonstrated a significant difference in vitamin B12 levels between recessive and dominant genotypes in case mothers (p < 0.05). CONCLUSION Additional studies are required to better understand the roles of parental gene polymorphisms related to folate-homocysteine metabolism in the pathogenesis of NTD.
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Affiliation(s)
- Kaouther Nasri
- Faculté des Sciences de Bizerte, Université de Carthage, Bizerte, Tunisia, .,UR 06/ SP14 Troubles du développement embryo-fœtal et placentaire, Service d'embryo-fœtopathologie, Centre de Maternité et de Néonatologie La Rabta et de la Faculté de Médecine de Tunis, Université El Manar II, Tunis, Tunisia,
| | - Fatma Midani
- UR 05/08-08, Département de biochimie, Hôpital la Rabta et de la Faculté de Médecine de Tunis, Université El Manar II, Tunis, Tunisia
| | - Amani Kallel
- UR 05/08-08, Département de biochimie, Hôpital la Rabta et de la Faculté de Médecine de Tunis, Université El Manar II, Tunis, Tunisia
| | - Nadia Ben Jemaa
- UR 06/ SP14 Troubles du développement embryo-fœtal et placentaire, Service d'embryo-fœtopathologie, Centre de Maternité et de Néonatologie La Rabta et de la Faculté de Médecine de Tunis, Université El Manar II, Tunis, Tunisia
| | - Mariem Aloui
- Faculté des Sciences de Bizerte, Université de Carthage, Bizerte, Tunisia.,UR 06/ SP14 Troubles du développement embryo-fœtal et placentaire, Service d'embryo-fœtopathologie, Centre de Maternité et de Néonatologie La Rabta et de la Faculté de Médecine de Tunis, Université El Manar II, Tunis, Tunisia
| | - Miryam Boulares
- Faculté des Sciences de Bizerte, Université de Carthage, Bizerte, Tunisia.,CERTE -Technopole de Borj-Cedria Laboratoire de Traitement et Valorisation des Rejets Hydriques, Soliman, Tunisia
| | - Mehdi Lassoued
- UR 05/08-08, Département de biochimie, Hôpital la Rabta et de la Faculté de Médecine de Tunis, Université El Manar II, Tunis, Tunisia
| | - Meriam Ben Halima
- UR 05/08-08, Département de biochimie, Hôpital la Rabta et de la Faculté de Médecine de Tunis, Université El Manar II, Tunis, Tunisia
| | - Safa Ben Wafi
- UR 05/08-08, Département de biochimie, Hôpital la Rabta et de la Faculté de Médecine de Tunis, Université El Manar II, Tunis, Tunisia
| | - Mariem Soussi
- UR 05/08-08, Département de biochimie, Hôpital la Rabta et de la Faculté de Médecine de Tunis, Université El Manar II, Tunis, Tunisia
| | - Imen Mahjoubi
- UR 05/08-08, Département de biochimie, Hôpital la Rabta et de la Faculté de Médecine de Tunis, Université El Manar II, Tunis, Tunisia
| | - Abir Baara
- UR 05/08-08, Département de biochimie, Hôpital la Rabta et de la Faculté de Médecine de Tunis, Université El Manar II, Tunis, Tunisia
| | - Mohamed Kacem Ben Fradj
- UR 05/08-08, Département de biochimie, Hôpital la Rabta et de la Faculté de Médecine de Tunis, Université El Manar II, Tunis, Tunisia
| | - Souhail Omar
- Laboratoire de Biologie clinique, Institut National Mongi Ben Hmida de Neurologie, Rue Jebbari La Rabta, Tunis, Tunisia
| | - Moncef Feki
- UR 05/08-08, Département de biochimie, Hôpital la Rabta et de la Faculté de Médecine de Tunis, Université El Manar II, Tunis, Tunisia
| | - Riadh Jemaa
- UR 05/08-08, Département de biochimie, Hôpital la Rabta et de la Faculté de Médecine de Tunis, Université El Manar II, Tunis, Tunisia
| | - Soumeya Siala Gaigi
- UR 06/ SP14 Troubles du développement embryo-fœtal et placentaire, Service d'embryo-fœtopathologie, Centre de Maternité et de Néonatologie La Rabta et de la Faculté de Médecine de Tunis, Université El Manar II, Tunis, Tunisia
| | - Raja Marrakchi
- Laboratoire de génétique, immunologie et pathologie humaine, faculté des sciences de Tunis, Université El Manar II, Tunis, Tunisia
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Lan G, Lin L, Chen X, Chen L, Chen X. Correlation Between Methylenetetrahydrofolate Reductase (MTHFR) C677T Polymorphisms and Pemetrexed Chemotherapy Efficacy/Toxicity in Non-Squamous Non-Small Cell Lung Cancer. Med Sci Monit 2017; 23:5683-5689. [PMID: 29186089 PMCID: PMC5718261 DOI: 10.12659/msm.904836] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Background In the present study, we aimed to retrospectively analyze the correlation between toxicity of pemetrexed (PEM) chemotherapy and methylenetetrahydrofolate reductase (MTHFR) C677T polymorphisms in patients with advanced non-squamous non-small cell lung cancer (non-sq NSCLC). Material/Methods We used polymerase chain reaction, gene scanning, and restriction fragment length polymorphism to analyze MTHFR C677T in 51 patients with advanced non-sq NSCLC. The patients received chemotherapies with single-agent PEM (monotherapy group) or with PEM combined with cisplatin (joint group). The correlation between MTHFR C677T polymorphisms and chemotherapy efficacy/toxicity was also assessed. Results There were 40 patients in the monotherapy group and 11 patients in the joint group. Among the 40 patients received single-agent PEM chemotherapy, those with the CT/TT genotype had higher incidence of leukopenia, neutropenia, nausea, and fatigue compared to patients with the with wild-type genotype CC (all P<0.05). However, polymorphisms of MTHFR C677T were not significantly associated with other adverse events and clinical outcomes. Conclusions Compared with genotype CC (the wild type), patients with the CT/TT genotype had higher incidence of leukopenia, neutropenia, nausea, and fatigue. Therefore, the MTHFR C677T polymorphism could be a predictive factor for leukopenia, neutropenia, nausea, and fatigue toxicities in non-sq NSCLC patients treated with single-agent PEM.
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Affiliation(s)
- Gaochen Lan
- Department of Medical Oncology, Fuzhou General Hospital of Nanjing Military Command, Fuzhou, Fujian, China (mainland)
| | - Lin Lin
- Department of Medical Oncology, Fuzhou General Hospital of Nanjing Military Command, Fuzhou, Fujian, China (mainland)
| | - Xiong Chen
- Department of Medical Oncology, Fuzhou General Hospital of Nanjing Military Command, Fuzhou, Fujian, China (mainland)
| | - Libin Chen
- Department of Medical Oncology, Fuzhou General Hospital of Nanjing Military Command, Fuzhou, Fujian, China (mainland)
| | - Xi Chen
- Department of Medical Oncology, Fuzhou General Hospital of Nanjing Military Command, Fuzhou, Fujian, China (mainland)
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Zhang MJ, Hu ZC, Yin YW, Li BH, Liu Y, Liao SQ, Gao CY, Li JC, Zhang LL. A meta-analysis of the relationship between MTHFR gene A1298C polymorphism and the risk of adult stroke. Cerebrovasc Dis 2014; 38:425-32. [PMID: 25472665 DOI: 10.1159/000369122] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 10/15/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The association between methylenetetrahydrofolate reductase (MTHFR) gene A1298C polymorphism and adult stroke remains controversial. The present article was designed to clarify this relationship through pooled analysis of the numerous epidemiological studies focusing on this association. METHODS We comprehensively searched all published papers in electronic database including PubMed, Embase, Web of Science, Chinese Biomedical Literature on disc (CBMdisc) and China National Knowledge Infrastructure (CNKI) up to 2013. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) for allelic (C allele vs. A allele), additive (CC vs. AA), dominant (CC+AC vs. AA), and recessive (CC vs. AA+AC) models were calculated. Subgroup and sensitivity analyses were performed to detect the heterogeneity and examine the reliability of results, respectively. Begg's funnel plots and Egger's regression test were used to assess the potential publication bias. RESULTS A total of fifteen studies containing 2,361 cases and 2,653 controls were included in the final meta-analysis. The combined results of overall analysis showed that there was significant association between MTHFR gene A1298C polymorphism and adult stroke (allelic model: OR=1.36, 95% CI=1.11-1.67; additive model: OR=1.88, 95% CI=1.12-3.18; dominant model: OR=1.33, 95% CI=1.08-1.65 and recessive model: OR=1.77, 95% CI=1.07-2.94, respectively). On subgroup analysis by ethnicity of study population, significant association was shown in meta-analysis based on Asian population (allelic model: OR=1.40, 95% CI=1.19-1.65; additive model: OR=2.58, 95% CI=1.34-4.96; dominant model: OR=1.44, 95% CI=1.20-1.73 and recessive model: OR=2.12, 95% CI=1.20-3.76, respectively), but not in Caucasian population (allelic model: OR=1.30, 95% CI=0.93-1.82; additive model: OR=1.65, 95% CI=0.81-3.33; dominant model: OR=1.17, 95% CI=0.86-1.61 and recessive model: OR=1.70, 95% CI=0.83-3.50, respectively). In addition, the heterogeneity was effectively removed or decreased by limiting the included studies with population of Asian ethnicity. Furthermore, the corresponding pooled ORs were not materially changed in all genetic models of meta-analysis after limiting the included studies with population-based controls. However, except the recessive model, publication bias presented in the allelic, additive, dominant models identified by the Begg's funnel plots and Egger's regression test. CONCLUSIONS In conclusion, the overall analysis suggests that MTHFR gene A1298C polymorphism plays an important role in the development of adult stroke. Genotype CC of MTHFR-1298A/C could increase the risk of stroke and may act as a predictor for clinical evaluation, especially in the Asian population. More studies with large-scale and different ethnicities are required to further confirm our findings.
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Affiliation(s)
- Ming-Jie Zhang
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Yuzhong District, Chongqing, PR China
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Nilsson TK, Böttiger AK, Henríquez P, Serra Majem L. MTHFR polymorphisms and serum cobalamin affect plasma homocysteine concentrations differentially in females and males. Mol Med Rep 2014; 10:2706-12. [PMID: 25176448 DOI: 10.3892/mmr.2014.2521] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 05/09/2014] [Indexed: 11/06/2022] Open
Abstract
A total of 523 subjects (297 females and 226 males) from the Canary Islands Nutrition Study (ENCA) were studied in order to examine the effect of the MTHFR 677C>T, 1298A>C and 1793G>A polymorphisms, adjusted for age, serum (S)‑folate and S‑cobalamin levels, on total plasma homocysteine concentrations (tHcy). Genotyping was performed with Pyrosequencing® technology. The MTHFR 677T‑allele was associated with increased tHcy concentrations only in males (P=0.005). The MTHFR 1298C‑allele was found to be associated with higher tHcy levels but similarly, only in males (P=0.025). The MTHFR 1793A‑allele was associated with decreased tHcy concentrations in the younger males (P=0.042). A haplotype‑based approach was marginally superior in explaining the genetic interaction of the MTHFR polymorphisms on tHcy plasma levels (R2 0.352 vs. 0.342 for a simple genotype‑based approach). A nutrigenetic interaction between the MTHFR 677C>T genotype and S‑cobalamin on tHcy levels was demonstrated in both genders. The increase in tHcy was more pronounced with decreasing S‑cobalamin quintiles in 677TT homozygotes (P=0.005 for males and P=0.015 for females) than with decreasing S‑folate quintiles (P for trend not significant). It was concluded that gene‑nutrient interactions may differ depending on the sex and age of the subjects. The transferability of gene‑nutrient interactions from one community to others may therefore be limited not only by different food patterns but also by different ages, genders and genotype distributions.
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Affiliation(s)
- Torbjörn K Nilsson
- Department of Medical Biosciences, Clinical Chemistry, Umeå University, Umeå SE‑90185, Sweden
| | - Anna K Böttiger
- Department of Laboratory Medicine, Clinical Chemistry, Örebro University Hospital, Örebro SE‑70185, Sweden
| | - Patricia Henríquez
- Nutrition Research Group, Research Institute of Biomedical and Health Sciences, University of Las Palmas of Gran Canaria, Las Palmas 35016, Canary Islands, Spain
| | - Lluís Serra Majem
- Nutrition Research Group, Research Institute of Biomedical and Health Sciences, University of Las Palmas of Gran Canaria, Las Palmas 35016, Canary Islands, Spain
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Thrombin generation in patients with idiopathic sudden sensorineural hearing loss. Thromb Res 2014; 133:1130-4. [DOI: 10.1016/j.thromres.2014.03.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 03/10/2014] [Accepted: 03/15/2014] [Indexed: 11/22/2022]
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D’Elia PQ, dos Santos AA, Bianco B, Barbosa CP, Christofolini DM, Aoki T. MTHFR polymorphisms C677T and A1298C and associations with IVF outcomes in Brazilian women. Reprod Biomed Online 2014; 28:733-8. [DOI: 10.1016/j.rbmo.2014.02.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 02/04/2014] [Accepted: 02/05/2014] [Indexed: 11/27/2022]
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Zappacosta B, Graziano M, Persichilli S, Di Castelnuovo A, Mastroiacovo P, Iacoviello L. 5,10-Methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms: genotype frequency and association with homocysteine and folate levels in middle-southern Italian adults. Cell Biochem Funct 2013; 32:1-4. [PMID: 24277487 DOI: 10.1002/cbf.3019] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 10/31/2013] [Accepted: 10/31/2013] [Indexed: 11/08/2022]
Abstract
Two genetic polymorphisms of methylenetetrahydrofolate reductase (MTHFR) gene (C677T and A1298C) can influence the plasma homocysteine (Hcy) levels, especially in the presence of an inadequate folate status. The aim of this study was to evaluate the frequencies of C677T and of A1298C MTHFR polymorphisms and their correlation with Hcy and serum folate concentrations in a population of blood donors living in a region of middle-southern Italy (the Molise Region). One hundred ninety seven blood donors were studied for total plasma Hcy, serum folate and C677T and A1298C MTHFR genotypes. The frequency of C677T genotypes was 20.8% (CC), 49.8% (CT) and 29.4% (TT); for the A1298C genotypes: 48.7% (AA), 43.7% (AC) and 7.6% (CC). Hcy and serum folate concentrations were significantly different among genotypes of the C677T polymorphism (CC versus CT versus TT: <0.0001 both for Hcy and folate), with Hcy values increasing, and serum folate decreasing, from CC to TT subjects. Regarding to A1298C polymorphism, the difference among genotypes (AA versus AC versus CC; p: 0.026 for Hcy and 0.014 for serum folate), showed an opposite trend for both parameters, with Hcy higher in the wild-type and lower in the homozygotes and serum folate higher in CC than in AA subjects. In conclusion, we found a high frequency of MTHFR allele associated with high level of Hcy and low levels of folate in an Italian southern population.
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Affiliation(s)
- Bruno Zappacosta
- Department of Laboratory Medicine, Fondazione di Ricerca e Cura 'Giovanni Paolo II'. Università Cattolica del S. Cuore, Campobasso, Italy
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Flavin-dependent enzymes in cancer prevention. Int J Mol Sci 2012; 13:16751-68. [PMID: 23222680 PMCID: PMC3546718 DOI: 10.3390/ijms131216751] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 11/26/2012] [Accepted: 12/04/2012] [Indexed: 12/13/2022] Open
Abstract
Statistical studies have demonstrated that various agents may reduce the risk of cancer's development. One of them is activity of flavin-dependent enzymes such as flavin-containing monooxygenase (FMO)(GS-OX1), FAD-dependent 5,10-methylenetetrahydrofolate reductase and flavin-dependent monoamine oxidase. In the last decade, many papers concerning their structure, reaction mechanism and role in the cancer prevention were published. In our work, we provide a more in-depth analysis of flavin-dependent enzymes and their contribution to the cancer prevention. We present the actual knowledge about the glucosinolate synthesized by flavin-containing monooxygenase (FMO)(GS-OX1) and its role in cancer prevention, discuss the influence of mutations in FAD-dependent 5,10-methylenetetrahydrofolate reductase on the cancer risk, and describe FAD as an important cofactor for the demethylation of histons. We also present our views on the role of riboflavin supplements in the prevention against cancer.
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Wang XW, Luo YL, Wang W, Zhang Y, Chen Q, Cheng YL. Association between MTHFR A1298C polymorphism and neural tube defect susceptibility: a metaanalysis. Am J Obstet Gynecol 2012; 206:251.e1-7. [PMID: 22265089 DOI: 10.1016/j.ajog.2011.12.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Revised: 11/29/2011] [Accepted: 12/19/2011] [Indexed: 12/11/2022]
Abstract
OBJECTIVE To determine whether 5,10-methylenetetrahydrofolate reductase A1298C polymorphism is associated with neural tube defect susceptibility. STUDY DESIGN Computerized literature searches of the PubMed, Embase, and Medline database were conducted to identify all eligible articles. Study subjects were classified as neural tube defect patients, mothers with neural tube defect offspring and fathers with neural tube defect offspring. The pooled odds ratios with 95% confidence interval (CI) were calculated by fixed-effects model or random-effects model. RESULTS Twenty-three case-control studies were finally included. The pooled results showed no significant association between 5,10-methylenetetrahydrofolate reductase A1298C polymorphism and neural tube defect susceptibility in any genetic contrast among the 3 groups, except 1 (AC vs AA in neural tube defect patients: odds ratio, 1.16; 95% CI, 1.10-1.32; P = .03), which, however, turned out to be of no statistical significance in the subgroup of the white population (odds ratio, 1.14; 95% CI, 0.98-1.31; P = .08). CONCLUSION This metaanalysis suggests that 5,10-methylenetetrahydrofolate reductase A1298C polymorphism is not associated with neural tube defect susceptibility in the white population.
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Bhaskar L, Murthy J, Venkatesh Babu G. Polymorphisms in genes involved in folate metabolism and orofacial clefts. Arch Oral Biol 2011; 56:723-37. [DOI: 10.1016/j.archoralbio.2011.01.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 01/18/2011] [Accepted: 01/18/2011] [Indexed: 11/24/2022]
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Al-Refai EA, Sadiq MF, Khassawneh MY, Amjad D. AN. Effect of methotrexate on the survival of human lymphocyte cultures carryingMTHFR677 (C>T) andMTHFR1298 (A>C) mutations. Drug Chem Toxicol 2009; 32:103-7. [DOI: 10.1080/01480540802584237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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16
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Genetic polymorphism of MTHFR G1793A in Chinese populations. Eur J Epidemiol 2008; 23:363-8. [DOI: 10.1007/s10654-008-9243-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2007] [Accepted: 03/23/2008] [Indexed: 10/22/2022]
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17
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Sabbagh AS, Mahfoud Z, Taher A, Zaatari G, Daher R, Mahfouz RA. High Prevalence of MTHFR GeneA1298CPolymorphism in Lebanon. ACTA ACUST UNITED AC 2008; 12:75-80. [DOI: 10.1089/gte.2007.0064] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Amira S. Sabbagh
- Department of Pathology and Laboratory Medicine, American University of Beirut Medical Center, Beirut, Lebanon
| | - Ziyad Mahfoud
- Department of Epidemiology and Population Health, American University of Beirut Medical Center, Beirut, Lebanon
| | - Ali Taher
- Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon
| | - Ghazi Zaatari
- Department of Pathology and Laboratory Medicine, American University of Beirut Medical Center, Beirut, Lebanon
| | - Rose Daher
- Department of Pathology and Laboratory Medicine, American University of Beirut Medical Center, Beirut, Lebanon
| | - Rami A.R. Mahfouz
- Department of Pathology and Laboratory Medicine, American University of Beirut Medical Center, Beirut, Lebanon
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Chapter 13 Methylenetetrahydrofolate Reductase, Common Polymorphisms, and Relation to Disease. FOLIC ACID AND FOLATES 2008; 79:375-92. [DOI: 10.1016/s0083-6729(08)00413-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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19
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Freitas AI, Mendonça I, Guerra G, Brión M, Reis RP, Carracedo A, Brehm A. Methylenetetrahydrofolate reductase gene, homocysteine and coronary artery disease: The A1298C polymorphism does matter. Inferences from a case study (Madeira, Portugal). Thromb Res 2008; 122:648-56. [DOI: 10.1016/j.thromres.2008.02.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2007] [Revised: 01/23/2008] [Accepted: 02/05/2008] [Indexed: 11/16/2022]
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20
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Mao R, Fan Y, Chen F, Sun D, Bai J, Fu S. Methylenetetrahydrofolate reductase gene polymorphisms in 13 Chinese ethnic populations. Cell Biochem Funct 2008; 26:352-8. [DOI: 10.1002/cbf.1450] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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21
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Eldibany MM, Caprini JA. Hyperhomocysteinemia and thrombosis: an overview. Arch Pathol Lab Med 2007; 131:872-84. [PMID: 17550314 DOI: 10.5858/2007-131-872-hatao] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/29/2007] [Indexed: 11/06/2022]
Abstract
CONTEXT Homocysteine, a sulfur-containing amino acid, absent in natural diets, is a metabolic intermediary in transmethylation and transsulfuration reactions. Such reactions are essential to normal cellular growth, differentiation, and function. Excess homocysteine is associated with vascular disease and related disorders. OBJECTIVE To review homocysteine metabolism, the pathogenesis and classification of hyperhomocysteinemia, and the published literature investigating the association of homocysteine and methylenetetrahydrofolate reductase defects with arterial and venous thromboembolism and related disorders. The role of vitamin supplementation in patients with hyperhomocysteinemia is addressed. DATA SOURCES Published medical and scientific literature. Articles addressing the objectives were selected and reviewed. Pertinent studies and conclusions were summarized, grouped, and contrasted. CONCLUSIONS The association of hyperhomocysteinemia and arterial and venous thrombosis is controversial. Severe hyperhomocysteinemia is associated with atherosclerosis. The effect of mild hyperhomocysteinemia is less certain. Coinheritance of methylenetetrahydrofolate reductase defects and factor V Leiden is likely to increase the risk of venous thromboembolism. The association of methylenetetrahydrofolate reductase defects combined with no additional thrombophilic risk factors with venous thrombosis is less clear. High doses of folic acid to lower homocysteine levels might not be necessary.
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Affiliation(s)
- Mohamed M Eldibany
- Department of Pathology and Laboratory Medicine, Evanston Northwestern Healthcare, Northwestern University Feinberg School of Medicine, Evanston, IL 60201, USA.
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22
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Ehrlich M, Woods CB, Yu MC, Dubeau L, Yang F, Campan M, Weisenberger DJ, Long T, Youn B, Fiala ES, Laird PW. Quantitative analysis of associations between DNA hypermethylation, hypomethylation, and DNMT RNA levels in ovarian tumors. Oncogene 2006; 25:2636-45. [PMID: 16532039 PMCID: PMC1449872 DOI: 10.1038/sj.onc.1209145] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
How hypermethylation and hypomethylation of different parts of the genome in cancer are related to each other and to DNA methyltransferase (DNMT) gene expression is ill defined. We used ovarian epithelial tumors of different malignant potential to look for associations between 5'-gene region or promoter hypermethylation, satellite, or global DNA hypomethylation, and RNA levels for ten DNMT isoforms. In the quantitative MethyLight assay, six of the 55 examined gene loci (LTB4R, MTHFR, CDH13, PGR, CDH1, and IGSF4) were significantly hypermethylated relative to the degree of malignancy (after adjustment for multiple comparisons; P < 0.001). Importantly, hypermethylation of these genes was associated with degree of malignancy independently of the association of satellite or global DNA hypomethylation with degree of malignancy. Cancer-related increases in methylation of only two studied genes, LTB4R and MTHFR, which were appreciably methylated even in control tissues, were associated with DNMT1 RNA levels. Cancer-linked satellite DNA hypomethylation was independent of RNA levels for all DNMT3B isoforms, despite the ICF syndrome-linked DNMT3B deficiency causing juxtacentromeric satellite DNA hypomethylation. Our results suggest that there is not a simple association of gene hypermethylation in cancer with altered DNMT RNA levels, and that this hypermethylation is neither the result nor the cause of satellite and global DNA hypomethylation.
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MESH Headings
- Adenocarcinoma, Mucinous/genetics
- Adenocarcinoma, Mucinous/pathology
- Adolescent
- Adult
- Aged
- Carcinoma, Endometrioid/genetics
- Carcinoma, Endometrioid/pathology
- Cystadenoma, Serous/genetics
- Cystadenoma, Serous/pathology
- DNA (Cytosine-5-)-Methyltransferase 1
- DNA (Cytosine-5-)-Methyltransferases/genetics
- DNA Methylation
- DNA Methyltransferase 3A
- DNA, Neoplasm
- Female
- Gene Expression Regulation, Neoplastic
- Humans
- Middle Aged
- Neoplasm Proteins/genetics
- Ovarian Neoplasms/genetics
- Ovarian Neoplasms/pathology
- RNA, Neoplasm/genetics
- RNA, Neoplasm/metabolism
- Tumor Suppressor Proteins
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Affiliation(s)
- M Ehrlich
- Tulane Cancer Center, Department of Biochemistry, and Human Genetics Program, Tulane Medical School, New Orleans, LA 70112, USA.
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O'Leary VB, Mills JL, Parle-McDermott A, Pangilinan F, Molloy AM, Cox C, Weiler A, Conley M, Kirke PN, Scott JM, Brody LC. Screening for new MTHFR polymorphisms and NTD risk. Am J Med Genet A 2005; 138A:99-106. [PMID: 16145688 DOI: 10.1002/ajmg.a.30846] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The enzyme, 5,10-methylenetetrahydrofolate reductase (MTHFR) plays a key role in cellular folate metabolism. The A222V (677C->T) polymorphism is a confirmed neural tube defect (NTD) risk factor within Irish and other populations. To search for other unknown single nucleotide polymorphisms (SNPs) that might play a role in the etiology of NTDs, we examined the entire MTHFR coding region in healthy individuals (n = 100). SNPs were identified using sequencing and database analysis and allele frequencies were determined in our Irish population. We identified P39P (116C->T; T allele frequency 0.13) and previously reported R594Q (1793G->A; Q allele frequency 0.07). We screened a large ethnically homogeneous Irish NTD cohort (n>1,300) for P39P and R594Q. A possible association between NTD cases and P39P (P = 0.034) was found but this was not confirmed by transmission disequilibrium testing. R594Q also showed some evidence of a NTD case association (P = 0.07). Further analysis indicated these observations are due to linkage disequilibrium with A222V (677C->T), and therefore these new SNPs are unlikely to be independent risk factors for NTDs. As rates of NTDs differ between ethnic groups, we examined allele and genotype frequencies of P39P and R594Q within African-American and American-Caucasian populations. This is the first NTD association study of both R594Q and the novel P39P. The association with NTD risk reported for these SNPs is driven by the linkage disequilibrium with the A222V (677C->T) NTD risk factor.
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Affiliation(s)
- Valerie B O'Leary
- Department of Biochemistry, Trinity College Dublin, Dublin, Ireland.
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Sazci A, Ergul E, Kaya G, Kara I. Genotype and allele frequencies of the polymorphic methylenetetrahydrofolate reductase gene in Turkey. Cell Biochem Funct 2005; 23:51-4. [PMID: 15386535 DOI: 10.1002/cbf.1132] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The polymorphic methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms C677T and A1298C cause mild hyperhomocysteinemia, not only in homozygotes for C677T, but also in compound heterozygotes for C677T/A1298C. The aim of this study was to determine allelic frequencies of the polymorphic MTHFR gene C677T, A1298C. In this regard, we have investigated the allelic frequencies of C677T and A1298C polymorphisms of the MTHFR gene in 1684 randomized individuals around Turkey. DNA samples isolated from peripheral blood samples of randomized individuals were analysed. The study population consisted of 1004 females and 680 males. The frequency in Turkey of the C677T was 42.9 %; of C677C, 47.4 %; and of T677T, 9.6 %. The frequency in Turkey of A1298C was 43.7 %; of A1298A, 46.3 %; and of C1298C, 10.0 %. The allelic frequencies of the T allele of MTHFR 677 and the C allele of MTHFR 1298 were 33.34 and 33.16 %, respectively. The frequency of C677T/A1298C compound heterozygosity is highest in Turkey (21.6 %), as compared to Canada (15 %), the United States (17 %) and The Netherlands (20 %).
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Affiliation(s)
- Ali Sazci
- Department of Medical Biology and Genetics, University of Kocaeli, Faculty of Medicine, Kocaeli, Turkey.
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Friso S, Girelli D, Trabetti E, Olivieri O, Guarini P, Pignatti PF, Corrocher R, Choi SW. The MTHFR 1298A>C polymorphism and genomic DNA methylation in human lymphocytes. Cancer Epidemiol Biomarkers Prev 2005; 14:938-43. [PMID: 15824167 DOI: 10.1158/1055-9965.epi-04-0601] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Methylenetetrahydrofolate reductase (MTHFR) balances the pool of folate coenzymes in one-carbon metabolism for DNA synthesis and methylation, both implicated in carcinogenesis. Epidemiologic studies have shown that two functional polymorphisms in MTHFR gene, 677C>T and 1298A>C, are related to increased cancer risk. We aimed to analyze lymphocyte DNA from 198 subjects to evaluate the MTHFR 1298A>C polymorphism and folate status affecting genomic DNA methylation as a possible mechanism underlying the relationship between MTHFR polymorphisms and cancer susceptibility. Carriers of the 1298AA wild-type genotype showed lower genomic DNA methylation compared with 1298AC or 1298CC genotypes [3.72 versus 8.59 or 6.79 ng 5-methyl-2'-deoxycytidine (5-mCyt)/microg DNA, P < 0.0001 and P = 0.007, respectively]. When DNA methylation was evaluated according to plasma folate status, only 1298AA with low folate levels revealed diminished DNA methylation (P < 0.0001). Moreover, when the two MTHFR polymorphisms were concomitantly evaluated at the low folate status, DNA methylation was reduced only in 1298AA/677TT compared with 1298AA/677CC (3.11 versus 7.29 ng 5-mCyt/microg DNA, P = 0.001) and 1298CC/677CC genotypes (3.11 versus 7.14 ng 5-mCyt/microg DNA, P = 0.004). However, the high prevalence of 677TT mutants within the 1298AA group (79%) and the similar biochemical features of 1298AA/677CC and 1298CC/677CC combined genotypes suggest that the gene-nutrient interaction affecting DNA methylation in 1298AA is mainly due to the coexistence of the 677TT genotype and that the 1298A>C polymorphism may convey its protective effect not through this interaction but through another pathway in one-carbon metabolism. Further mechanistic studies are warranted to investigate how single polymorphisms as well as MTHFR combined genotypes exert their effect on cancer susceptibility.
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Affiliation(s)
- Simonetta Friso
- Department of Clinical and Experimental Medicine, University of Verona, Policlinico Giambattista Rossi, Piazza Ludovico Antonio Scuro, 10, 37134 Verona, Italy.
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Almadori G, Bussu F, Galli J, Cadoni G, Zappacosta B, Persichilli S, Minucci A, Giardina B, Maurizi M. Serum levels of folate, homocysteine, and vitamin B12 in head and neck squamous cell carcinoma and in laryngeal leukoplakia. Cancer 2005; 103:284-92. [PMID: 15593092 DOI: 10.1002/cncr.20772] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND The authors evaluated serum levels of folate, homocysteine, and vitamin B(12) in patients with head and neck squamous cell carcinoma (HNSCC) and in patients with laryngeal leukoplakia, a well known preneoplastic lesion. METHODS One hundred forty-four consecutive, untreated patients with HNSCC and 40 consecutive, untreated patients with laryngeal leukoplakia were enrolled in the Department of Otolaryngology at the authors' institution. Data from those patients were compared with data from one control group, which included 90 smokers, and from another control group, which included 120 nonsmokers. Serum levels of homocysteine, folate, and vitamin B(12) were measured by an automated immunoassay method based on fluorescence polarization immunoassay technology. RESULTS Comparing groups by Student-Newman-Keuls test, serum folate levels were significantly lower in patients with HNSCC and in patients with laryngeal leukoplakia compared with serum folate levels in both the smoker control group and the nonsmoker control group. Serum homocysteine levels in patients with HNSCC were significantly higher compared with homocysteine levels both in the smoker and nonsmoker control groups and in patients with laryngeal leukoplakia. There were no statistically significant differences between groups in serum vitamin B(12) levels. CONCLUSIONS A role for folate deficiency as a risk factor in head and neck carcinogenesis is plausible. A chemoprevention protocol with folate is both feasible and ethically correct and is in progress at the authors' institution. Homocysteine levels in patients with HNSCC probably are affected largely by the HNSCC phenotype. An accumulation of homocysteine may reveal a genetic defect, which, theoretically, may be a target for pharmacologic therapy, for example, with antifolic drugs.
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Affiliation(s)
- Giovanni Almadori
- Institute of Otolaryngology, Università Cattolica del Sacro Cuore, Rome, Italy.
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Parle-McDermott A, Mills JL, Kirke PN, Cox C, Signore CC, Kirke S, Molloy AM, O'Leary VB, Pangilinan FJ, O'Herlihy C, Brody LC, Scott JM. MTHFD1 R653Q polymorphism is a maternal genetic risk factor for severe abruptio placentae. Am J Med Genet A 2005; 132A:365-8. [PMID: 15633187 DOI: 10.1002/ajmg.a.30354] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This study examined the relationship between folate/homocysteine-related genetic polymorphisms: MTHFD1 1958G --> A (R653Q), MTHFR 677C --> T (A222V), MTHFR 1298A --> C (E429A), and risk of severe abruptio placentae. We genotyped 62 women with a pregnancy history complicated by severe abruptio placentae and 184 control pregnancies. Analysis of the MTHFD1 1958G --> A (R653Q) polymorphism showed increased frequency of the 'QQ' homozygote genotype in pregnancies affected by severe abruptio placentae compared to control pregnancies (odds ratio 2.85 (1.47-5.53), P = 0.002). In contrast to previous reports, the MTHFR polymorphisms 677C --> T (A222V) and 1298A --> C (E429A) were not associated with abruptio placentae risk in our cohort, when analyzed either independently or in combination. We conclude that women who are 'QQ' homozygote for the MTHFD1 1258G --> A (R653Q) polymorphism are almost three times more likely to develop severe abruptio placentae during their pregnancy than women who are 'RQ' or 'RR.'
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Winkelmayer WC, Sunder-Plassmann G, Huber A, Födinger M. Patterns of co-occurrence of three single nucleotide polymorphisms of the 5,10-methylenetetrahydrofolate reductase gene in kidney transplant recipients. Eur J Clin Invest 2004; 34:613-8. [PMID: 15379760 DOI: 10.1111/j.1365-2362.2004.01394.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Recently, a new mutation of the 5,10-methylenetetrahydrofolate reductase (MTHFR) encoding gene was first described (1793G > A). Only few reports have studied the prevalence of this polymorphism, especially in combination with other MTHFR mutations (677C > T, 1298A > C). METHODS We cross-sectionally identified the novel MTHFR 1793G > A polymorphism in 730 kidney transplant recipients. MTHFR 677C > T and 1298A > C were also assessed and the frequency of each was described individually as well as in cross-tabulation with the other MTHFR genotypes. The expected number of patients for each MTHFR genotype combination was calculated and contrasted with the observed numbers. Fisher's exact test was used for statistical inference. RESULTS The allelic frequency of MTHFR 1793G > A was 0.052. Seventy-two patients (9.9%) were heterozygous and two patients (0.3%) were homozygous. From the cross-tabulations, we identified 53 patients (expected: 33.6) with the MTHFR 1298AC/1793GA genotype and 17 patients (expected: 6.7) with the MTHFR 1298CC/1793GA genotype. Furthermore, we found two patients with double homozygosity for MTHFR 1793G > A and MTHFR 1298A > C (MTHFR 1793AA/1298CC genotype). The frequencies of these genotype combinations were substantially larger than could be expected (P < 0.001). CONCLUSIONS These findings suggest a selection or survival advantage for individuals with combined MTHFR 1793G > A and MTHFR 1298A > C genotypes, possibly owing to a mutually stabilizing effect on MTHFR enzyme activity.
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Affiliation(s)
- W C Winkelmayer
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02120, USA.
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Cicek MS, Nock NL, Li L, Conti DV, Casey G, Witte JS. Relationship between Methylenetetrahydrofolate Reductase C677T and A1298C Genotypes and Haplotypes and Prostate Cancer Risk and Aggressiveness. Cancer Epidemiol Biomarkers Prev 2004. [DOI: 10.1158/1055-9965.1331.13.8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Abstract
Previous reports indicate that polymorphisms in the MTHFR gene play a role in cancer development, but their potential impact on prostate cancer has not been well studied. Here, we evaluate the association between two MTHFR polymorphisms, C677T and A1298C, and prostate cancer risk and aggressiveness in a moderately large family-based case-control study (439 cases and 479 sibling controls). Among all study subjects, we observed no association between the C677T variant and prostate cancer but a slight positive association between the A1298C variant and risk of this disease [odds ratio (OR) 1.41, 95% confidence interval (CI) 0.96-2.06; P = 0.08]. When stratifying the study population by disease aggressiveness at diagnosis, the C677T variant was positively associated with risk among men with less advanced disease (OR 1.86, 95% CI 1.00-3.46; P = 0.05). In contrast, when looking at men with more advanced disease, the C677T variant was inversely associated with risk (OR 0.51, 95% CI 0.32-0.82; P = 0.01), whereas the A1298C variant was positively associated with risk (OR 1.79, 95% CI 1.06-3.02; P = 0.03). Furthermore, the 677T-1298A haplotype was positively associated with prostate cancer among men with less advanced disease (OR 1.84, 95% CI 1.07-3.16; P = 0.03) and inversely associated with risk of more advanced disease (OR 0.47, 95% CI 0.29-0.76; P = 0.002). Our findings suggest that 677T and 1298A, or another variant on their haplotype, may be associated with a reduced risk of progression to more advanced prostate cancer.
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Affiliation(s)
- Mine S. Cicek
- 1Department of Cancer Biology, Cleveland Clinic Lerner College of Medicine, Cleveland, Ohio
| | - Nora L. Nock
- 2Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, Ohio
| | - Li Li
- 2Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, Ohio
| | - David V. Conti
- 3Department of Preventive Medicine, University of Southern California, Los Angeles, California; and
| | - Graham Casey
- 1Department of Cancer Biology, Cleveland Clinic Lerner College of Medicine, Cleveland, Ohio
| | - John S. Witte
- 4Department of Epidemiology and Biostatistics, University of California-San Francisco, San Francisco, California
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Parle-McDermott A, Mills JL, Kirke PN, O'Leary VB, Swanson DA, Pangilinan F, Conley M, Molloy AM, Cox C, Scott JM, Brody LC. Analysis of the MTHFR 1298A-->C and 677C-->T polymorphisms as risk factors for neural tube defects. J Hum Genet 2003; 48:190-3. [PMID: 12730722 DOI: 10.1007/s10038-003-0008-4] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2002] [Accepted: 01/28/2003] [Indexed: 11/25/2022]
Abstract
The thermolabile variant (677TT) of methylenetetrahydrofolate reductase (MTHFR) is a known risk factor for neural tube defects (NTDs). The relationship between a second MTHFR polymorphism (1298A-->C) and NTD risk has been inconsistent between studies. We genotyped 276 complete NTD triads (mother, father and child affected with an NTD) and 256 controls for MTHFR 1298A-->C. Our findings do not support a role for the 1298A-->C polymorphism in NTDs (OR 0.85 (95% CI 0.49-1.47), p= 0.55), nor do we observe a combined effect with the 677C-->T polymorphism.
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Ryan BM, Molloy AM, McManus R, Arfin Q, Kelleher D, Scott JM, Weir DG. The methylenetetrahydrofolate reductase (MTHFR) gene in colorectal cancer: role in tumor development and significance of allelic loss in tumor progression. INTERNATIONAL JOURNAL OF GASTROINTESTINAL CANCER 2003; 30:105-11. [PMID: 12540022 DOI: 10.1385/ijgc:30:3:105] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND AND AIM Folate deficiency predisposes to sporadic colorectal cancer (CRC). Methylenetetrahydrofolate reductase (MTHFR) is a critical folate-metabolising enzyme and a polymorphism at position 677 (C677T), is associated with reduced enzyme activity. We investigated whether this functional polymorphism modulates the risk of developing CRC. METHODS This was a retrospective case-control study. 136 unselected cases of sporadic CRC and 848 normal population controls were genotyped for the MTHFR C677T polymorphism. Tumor tissue was genotyped to assess loss of heterozygosity (LOH). RESULTS MTHFR CT heterozygotes had a significantly increased risk of developing CRC (53.7% of CRC cases vs 38.4% of controls), odds ratio 1.86 (95% CI 1.3-2.7, p < 0.005). No increased cancer risk was observed in TT homozygotes. The MTHFR 'T' allele frequency was significantly higher in the cancer group (0.3713) as compared to controls (0.2900, p < 0.008). LOH at the MTHFR locus was observed in 18% of informative cancers, with exclusive loss of the variant 'T' allele, in all cases. CONCLUSION In this study of a homogenous northern European population, MTHFR CT heterozygotes had an almost two-fold increased risk of developing sporadic CRC. The exclusive pattern of MTHFR allele loss in cases of LOH, suggest that functional MTHFR activity within a tumor might play an important role in the survival and progression of a colonic neoplasm.
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Affiliation(s)
- B M Ryan
- Department of Gastroenterology and Clinical Medicine, St. James's Hospital and Trinity College, Dublin, Ireland.
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Semenza JC, Delfino RJ, Ziogas A, Anton-Culver H. Breast cancer risk and methylenetetrahydrofolate reductase polymorphism. Breast Cancer Res Treat 2003; 77:217-23. [PMID: 12602921 DOI: 10.1023/a:1021843019755] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Methylenetetrahydrofolate reductase (MTHFR), a polymorphic enzyme involved in folate metabolism, plays a role in DNA biosynthesis, methylation, and repair in actively dividing cells. Because breast-cell division occurs in women with active ovulatory cycles, polymorphisms in the MTHFR gene could be a risk factor for breast cancer. METHODS We genotyped 352 clinic-based study subjects for MTHFR, 105 subjects with breast cancer and 247 with benign breast disease, histopathologically classified as high-risk or low-risk for breast cancer. Questionnaire data were collected prior to biopsy to blind subjects and interviewers to diagnoses. RESULTS Premenopausal women with the MTHFR polymorphism had a threefold increased breast cancer risk (OR = 2.8; 95%CI: 1.02-7.51) compared to the clinic-based controls with benign breast disease. Results were similar using either low- or high-risk controls. However, risk for postmenopausal women was not elevated (OR = 0.8; 95%CI 0.4-1.4). No significant interaction between genotype and smoking or alcohol was found, but polymorphic MTHFR decreased the likelihood of drinking alcohol (OR = 0.5; 95%CI 0.3-0.9). CONCLUSION These data suggest that polymorphic MTHFR increases risk of premenopausal, but not postmenopausal, breast cancer. These findings should be explored with a larger sample size in order to analyze gene-environment interactions between MTHFR and folate. Once the intricate relationship between diet and breast cancer has been elucidated, new cancer control initiatives can be considered such as folate chemoprevention trials in high-risk individuals.
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Affiliation(s)
- Jan C Semenza
- School of Community Health, College of Urban and Public Affairs, Portland State University, Portland, OR, USA
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Esfahani ST, Cogger EA, Caudill MA. Heterogeneity in the prevalence of methylenetetrahydrofolate reductase gene polymorphisms in women of different ethnic groups. JOURNAL OF THE AMERICAN DIETETIC ASSOCIATION 2003; 103:200-7. [PMID: 12589326 DOI: 10.1053/jada.2003.50030] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECTIVE To determine the prevalence of methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms in women of different ethnic groups and to relate these common mutations to plasma homocysteine, red cell folate, and serum folate. DESIGN A one-time fasting blood sample was obtained for MTHFR genotype (C677T and A1298C) determinations (n=433). Serum folate, red cell folate, and homocysteine analyses were performed in nonfolic acid supplement users (n=215). SUBJECTS/SETTING This study involved 433 women from four ethnic groups, including 193 Hispanic women of Mexican descent, 139 white women, 53 Asian women of mixed descent, and 48 African American women. STATISTICAL ANALYSIS PREFORMED: Chi;(2), t Test, and analysis of variance were used. RESULTS Mexican women (18.1%) had a higher frequency of the 677 TT genotype compared with white (7.2%), Asian (3.8%), and African American (0%) women. White women (7.9%) had a higher frequency of the 1298 CC genotype than the other ethnic groups (range=1.9% to 2.6%). The frequency of compound heterozygosity (677 CT + 1298 AC) was higher in Mexican (17.6%) and white (15.1%) women than Asian and African American ( approximately 4% to 6%) women. In the era of folic acid fortification, neither genotype, independently or together, was associated with homocysteine or blood folate concentrations when ethnic groups were combined. In Mexican women, however, a linear trend (P</=.05) was detected for the C677T variants with the lowest red cell folate in the TT genotype. APPLICATIONS/CONCLUSIONS These data demonstrate ethnic differences in genetic polymorphisms that are diet responsive and may be useful when investigating ethnic variations in chronic disease, developmental anomalies, and folate requirements.
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Affiliation(s)
- Setareh Torabian Esfahani
- Agricultural Sciences in the Human Nutrition and Food Science Department, Cal Poly Pomona University, Pomona, CA 91768, USA
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Sekhon J, Pereira P, Sabbaghian N, Schievella AR, Rozen R. Antisense inhibition of methylenetetrahydrofolate reductase reduces survival of methionine-dependent tumour lines. Br J Cancer 2002; 87:225-30. [PMID: 12107847 PMCID: PMC2376111 DOI: 10.1038/sj.bjc.6600459] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2001] [Revised: 01/30/2002] [Accepted: 03/21/2002] [Indexed: 11/28/2022] Open
Abstract
Transformed cells have been documented to be methionine-dependent, suggesting that inhibition of methionine synthesis might be useful for cancer therapy. Methylenetetrahydrofolate reductase synthesises 5-methyltetrahydrofolate, the methyl donor utilised in methionine synthesis from homocysteine by vitamin B(12)-dependent methionine synthase. We hypothesised that methylenetetrahydrofolate reductase inhibition would affect cell viability through decreased methionine synthesis. Using medium lacking methionine, but containing homocysteine and vitamin B(12) (M-H+), we found that nontransformed human fibroblasts could maintain growth. In contrast, four transformed cell lines (one colon carcinoma, two neuroblastoma and one breast carcinoma) increased proliferation only slightly in the M-H+ medium. To downregulate methylenetetrahydrofolate reductase expression, two phosphorothioate antisense oligonucleotides, EX5 and 677T, were used to target methylenetetrahydrofolate reductase in the colon carcinoma line SW620; 400 nM of each antisense oligonucleotide decreased cell survival by approximately 80% (P<0.01) and 70% (P<0.0001), respectively, compared to cell survival after the respective control mismatched oligonucleotide. Western blotting and enzyme assays confirmed that methylenetetrahydrofolate reductase expression was decreased. Two neuroblastoma and two breast carcinoma lines also demonstrated decreased survival following EX5 treatment whereas nontransformed human fibroblasts were not affected. This study suggests that methylenetetrahydrofolate reductase may be required for tumour cell survival and that methylenetetrahydrofolate reductase inhibition should be considered for anti-tumour therapy.
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Affiliation(s)
- J Sekhon
- Department of Human Genetics, McGill University Health Centre - Montreal Children's Hospital, 4060 Ste. Catherine West, Room 200, Montreal, Quebec H3Z 2Z3, Canada
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Rothenbacher D, Fischer HG, Hoffmeister A, Hoffmann MM, März W, Bode G, Rosenthal J, Koenig W, Brenner H. Homocysteine and methylenetetrahydrofolate reductase genotype: association with risk of coronary heart disease and relation to inflammatory, hemostatic, and lipid parameters. Atherosclerosis 2002; 162:193-200. [PMID: 11947914 DOI: 10.1016/s0021-9150(01)00699-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
AIM It has been suggested that homocysteine (tHcy) levels and methylenetetrahydrofolate reductase (MTHFR) genotype are primary risk factors for coronary heart disease (CHD). We performed a case-control study to investigate whether tHcy levels and MTHFR genotype (677 C-->T mutation and 1298 A-->C mutation) are associated with CHD under special consideration of the possibility for confounding. METHODS German speaking patients aged 40-68 years who underwent coronary angiography at the University of Ulm between April 1996 and November 1997 and who had at least one coronary stenosis greater than 50% were included in the study. Controls were sampled from voluntary blood donors and were matched for sex and age. tHcy levels were measured by high performance liquid chromatography and MTHFR genotype by means of polymerase chain reaction. In addition, C-reactive protein, fibrinogen, plasma viscosity, leukocytes, HDL-cholesterol and Lp(a) were determined. RESULTS Overall, 312 patients and 479 controls were enrolled in the study (response in patients 78%, in controls 84%). Mean tHcy value was 9.43 micromol/l in CHD patients and 8.91 micromol/l in controls (P=0.145). Prevalence of 677TT-polymorphism was 9.9% in patients and 10.4% in controls (P=0.295). Prevalence of 1298CC-polymorphism was 9.7% in patients and 13.8% in controls (P=0.346). There was a clear association of tHcy-values, but not of 677TT- or 1298CC-genotype with conventional CHD risk factors. After adjustment for these risk factors no increased risk for CHD could be associated with increased tHcy-values, with 677TT or 1298CC-genotype, or with their combination. Also no statistically significant relationships of these parameters to inflammatory, rheologic or hemostatic parameters or lipids were detectable. CONCLUSION These results do not confirm an independent relationship of tHcy values and MTHFR genotype with risk of CHD in the population studied.
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Affiliation(s)
- D Rothenbacher
- Department of Epidemiology, The German Centre for Research on Ageing, Heidelberg, Germany
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Almadori G, Bussu F, Galli J, Cadoni G, Zappacosta B, Persichilli S, Minucci A, Giardina B. Serum folate and homocysteine levels in head and neck squamous cell carcinoma. Cancer 2002; 94:1006-11. [PMID: 11920469 DOI: 10.1002/cncr.10343] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND Local and systemic metabolic alterations are always present in cancer. Carcinogenesis is associated with biochemical disorders, often nonspecific, that might promote or derive from tumoral progression. Thus, analysis of metabolic alterations may be a valuable approach to understanding the biochemistry of tumors and may provide a means of identifying new targets for therapy. The methionine cycle in particular has been extensively studied in human cancer. METHODS The authors analyzed serum concentrations of two metabolites of such pathways, folate and homocysteine, in 42 patients affected by head and neck squamous cell carcinoma (HNSCC) in comparison with two control groups, composed of smokers and non smokers. RESULTS Mean folate level was 5.8 +/- 2.1 ng/mL in carcinoma patients, 9.1 +/- 2.7 ng/mL in smoking controls, and 9.7 +/- 2.2 ng/mL in non smoking controls, with a statistically significant difference between carcinoma patients and smokers (mean difference: -3.3 ng/mL; 95% confidence interval [CI]: -4.234 to -2.366; P < 0.0001) and between carcinoma patients and non smokers (mean difference: -3.9 ng/mL; 95% CI: -4.67 to -3.13; P < 0.0001). Mean total homocysteine level was 10.4 +/- 5.3 microM in carcinoma patients, 7.8 +/- 2.5 microM in the non-smokers' group, and 8.3 +/- 2.8 microM in the smokers' group, with statistically significant differences between carcinoma patients and smoking controls (mean difference: 2.1 microM; 95% CI: 0.7056 to 3.494; P = 0.0034) and between carcinoma patients and non smoking controls (mean difference: 2.6 microM; 95% CI: 1.381 to 3.819; P < 0.0001). CONCLUSIONS Differences in serum levels of folate and homocysteine might arise from tumor development and consequent metabolic alterations or might precede and promote tumor progression. If hypofolatemia is a risk factor for head and neck carcinogenesis, it might suggest a role for folate as a novel chemopreventive agent both in patients with precancerous lesions and in patients with treated HNSCC at risk for loco-regional recurrence and second primary tumors.
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Affiliation(s)
- Giovanni Almadori
- Institute of Otolaryngology, Universtitá Cattolica del Sacro Cuore, Rome, Italy.
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Tröndle U, Sunder-Plassmann G, Burgmann H, Buchmayer H, Kramer L, Bieglmayer C, Hörl WH, Födinger M. Molecular and clinical characterisation of homocystinuria in two Austrian families with cystathionine beta-synthase deficiency. ACTA MEDICA AUSTRIACA 2002; 28:145-51. [PMID: 11774777 DOI: 10.1046/j.1563-2571.2001.01035.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The influence of the genotype on the phenotypic expression of homocystinuria due to cystathionine beta-synthase (CBS) deficiency is frequently unclear. We therefore investigated the genotype and the phenotype of CBS deficiency in two Austrian families also considering genetic polymorphisms with a putative association with vascular disease (MTHFR 677C-->T, MTHFR 1298A-->C, F5 1691G-->A, F2 20210G-->A) and response to therapy. We identified the CBS 833T-->C/1058C-->T and CBS 828ins104/1358del134 compound heterozygous genotype in our index patients. Both patients showed mental retardation and ectopia lentis. CBS 833T-->C/1058C-->T was associated with severe vascular complications, which was not the case for CBS 828ins104/1358del134. The patient with CBS 828ins104/1358del134 was negative for F5 1691G-->A, F2 20210G-->A, MTHFR 677C-->T, and MTHFR 1298A-->C, while the patient with CBS 833T-->C/1058C-->T was heterozygous for MTHFR 1298A-->C. A combination therapy including pyridoxine, folic acid, hydroxycobalamin, and betaine failed to lower total homocysteine plasma levels below 50 mumol/L in both patients. In summary, our study demonstrates that the CBS 833C/1058T-MTHFR 1298AC genotype can be related to severe vascular disease, while the CBS 828ins104/1358del134-MTHFR 1298AA genotype presents with a somewhat milder clinical phenotype. Both genotypes do not allow for normalisation of total homocysteine plasma levels following vitamin therapy.
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Affiliation(s)
- U Tröndle
- Department of Laboratory Medicine, Division of Endocrinology and Metabolism, University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna
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Feix A, Fritsche-Polanz R, Kletzmayr J, Vychytil A, Hörl WH, Sunder-Plassmann G, Födinger M. Increased prevalence of combined MTR and MTHFR genotypes among individuals with severely elevated total homocysteine plasma levels. Am J Kidney Dis 2001; 38:956-64. [PMID: 11684547 DOI: 10.1053/ajkd.2001.28581] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The prevalence of the methionine synthase (MTR) 2756A-->G polymorphism among individuals with severely elevated total homocysteine (tHcy) plasma levels is unknown. Therefore, 1,716 subjects, including 415 hemodialysis patients, 179 peritoneal dialysis patients, 733 kidney graft recipients, and 389 healthy subjects, were investigated. The distribution of MTR 2756A-->G, as well as 5,10-methylenetetrahydrofolate reductase (MTHFR) 677C-->T/1298A-->C, genotypes among study participants with extremely high tHcy plasma levels (>90th percentile) was compared with the genotype distribution of subjects with very low tHcy plasma levels (<10th percentile). The prevalence of MTR 2756AG and GG genotypes alone did not differ between individuals with extremely high or extremely low tHcy levels (P = 0.7402; odds ratio [OR], 1.076; 95% confidence interval [CI], 0.697 to 1.662). Conversely, combined MTR and MTHFR genotypes (MTR 2756AG and 2756GG and MTHFR 677TT/1298AA and 677CT/1298AC) were found more often in the highest (n = 34) compared with the lowest plasma tHcy decile (n = 19; P = 0.0252; OR, 1.983; 95% CI, 1.079 to 3.643). The number of patients with the wild-type MTR and MTHFR genotype was three times greater in the lowest compared with the highest decile (17 versus 6 patients, respectively; P = 0.0155; OR, 0.330; 95% CI, 0.126 to 0.861). In summary, our study shows that the 2756A-->G transition of MTR in combination with MTHFR 677TT/1298AA and 677CT/1298AC can be associated with extremely high tHcy plasma levels.
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Affiliation(s)
- A Feix
- Department of Medicine III, Division of Nephrology and Dialysis, Division of Endocrinology and Metabolism, University of Vienna, Austria.
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Stevenson JP, Redlinger M, Kluijtmans LA, Sun W, Algazy K, Giantonio B, Haller DG, Hardy C, Whitehead AS, O'Dwyer PJ. Phase I clinical and pharmacogenetic trial of irinotecan and raltitrexed administered every 21 days to patients with cancer. J Clin Oncol 2001; 19:4081-7. [PMID: 11600611 DOI: 10.1200/jco.2001.19.20.4081] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PURPOSE Irinotecan and raltitrexed display schedule-dependent synergy in vitro, which supports the clinical investigation of the combination. Functional polymorphisms of the methylenetetrahydrofolate reductase (MTHFR) gene result in intracellular redistribution of folate derivatives, which may affect raltitrexed-associated cytotoxicity. PATIENTS AND METHODS Patients with a range of solid cancers and good performance status received irinotecan as a 90-minute infusion on day 1 and raltitrexed as a 15-minute infusion on day 2, repeated every 21 days. Samples were collected for MTHFR C677T genotyping and fasting plasma homocysteine during the first cycle. RESULTS Thirty-nine assessable patients received 127 cycles of therapy. Irinotecan doses ranged from 100 to 350 mg/m(2), and raltitrexed, 1.0 to 4.0 mg/m(2). Raltitrexed doses of more than 3.0 mg/m(2) were not tolerated and were associated with dose-limiting asthenia, diarrhea, and AST/ALT elevation. Irinotecan/raltitrexed doses of 350/3.0 mg/m(2) were well-tolerated; principal toxicities included neutropenia, diarrhea, and fatigue. Two partial responses were observed in patients with pretreated gastroesophageal cancers. Homozygotes with the MTHFR 677 TT polymorphism incurred significantly less raltitrexed-associated toxicity than those with either wild-type or heterozygous genotypes (P = .05). No significant differences were noted in plasma homocysteine values between the genotypic subtypes, and plasma homocysteine levels did not predict the risk of toxicity. CONCLUSION Irinotecan and raltitrexed doses of 350 and 3.0 mg/m(2) are recommended for further study on a day 1, 2 schedule every 21 days. Efficacy results suggest that trials in upper and lower gastrointestinal malignancies are warranted. MTHFR C677T genotypes may be predictive of clinical raltitrexed toxicity.
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Affiliation(s)
- J P Stevenson
- Developmental Therapeutics Program, University of Pennsylvania, Philadelphia, USA.
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40
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Födinger M, Buchmayer H, Heinz G, Papagiannopoulos M, Kletzmayr J, Perschl A, Vychytil A, Hörl WH, Sunder-Plassmann G. Association of two MTHFR polymorphisms with total homocysteine plasma levels in dialysis patients. Am J Kidney Dis 2001; 38:77-84. [PMID: 11431185 DOI: 10.1053/ajkd.2001.25197] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The effect of the combined 5,10-methylenetetrahydrofolate reductase (MTHFR) 677C-->T and 1298A-->C genotype on total homocysteine (tHcy), folate, and vitamin B(12) plasma levels was investigated in 983 subjects, including 415 hemodialysis patients, 179 peritoneal dialysis patients, and 389 healthy individuals. Mean tHcy plasma concentrations were 27.2 +/- 15.8 micromol/L in hemodialysis patients, 25.4 +/- 19.1 micromol/L in peritoneal dialysis patients, and 8.9 +/- 3.5 micromol/L in healthy individuals. Hyperhomocysteinemia (tHcy > 15 micromol/L) was detected in 81.6% of patients and 2.6% of controls. Multiple stepwise regression analysis showed that the MTHFR 677C-->T/1298A-->C genotype (CC/AA, CC/AC, CC/CC, CT/AA, CT/AC, TT/AA), vitamin use, age, folate and vitamin B(12) plasma level were significant predictors of tHcy plasma levels. Analysis of variance showed that this effect of MTHFR genotypes on tHcy level was caused by significantly greater tHcy levels in 677TT/1298AA hemodialysis and peritoneal dialysis patients versus other genotypes. Compound heterozygous controls (677CT/1298AC genotype) had significantly greater tHcy levels compared with 677CC/1298AA controls. There was no major effect of MTHFR polymorphisms on folate and vitamin B(12) plasma concentrations. This study shows that the MTHFR 677TT/1298AA genotype, but not the 677CT/1298AC genotype, is a significant predictor of tHcy plasma levels in dialysis patients.
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Affiliation(s)
- M Födinger
- Department of Medicine III, Division of Nephrology and Dialysis, University of Vienna, Austria.
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Piyathilake CJ, Johanning GL, Macaluso M, Whiteside M, Oelschlager DK, Heimburger DC, Grizzle WE. Localized folate and vitamin B-12 deficiency in squamous cell lung cancer is associated with global DNA hypomethylation. Nutr Cancer 2001; 37:99-107. [PMID: 10965526 DOI: 10.1207/s15327914nc3701_13] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
We measured the concentrations of folate and vitamin B-12 in paired tissue samples of squamous cell cancer (SCC) and adjacent grossly normal-appearing uninvolved bronchial mucosa (from which SCC developed and also "at risk" of developing SCC) of the lung in 12 subjects to determine the involvement of these vitamins in 1) lung carcinogenesis and 2) global DNA methylation. The folate concentrations were significantly lower in SCCs than in uninvolved tissues (p = 0.03). The vitamin B-12 concentrations were also significantly lower in SCCs than in uninvolved tissues (p = 0.02). The radiolabeled methyl incorporation (inversely related to the degree of in vivo DNA methylation) was significantly higher in SCCs than in uninvolved tissues (p < 0.0001). The correlation between folate and radiolabeled methyl incorporation was inverse and statistically significant in SCCs (p = 0.03). The correlation between vitamin B-12 and radiolabeled methyl incorporation also was inverse and statistically significant in SCCs (p = 0.009). The relationship between tissue vitamin B-12 and DNA methylation was minimal in uninvolved tissues. The relationship between folate and DNA methylation, however, was inverse in uninvolved tissues. In the multiple regression models that included both vitamins, only folate was inversely associated with radiolabeled methyl incorporation in uninvolved and cancerous tissues. These results suggested that folate might be the limiting vitamin for proper DNA methylation in SCC as well as in tissues at risk of developing SCC. Several possible mechanisms of folate deficiency, including inactivation of the vitamin by exposure to carcinogens of cigarette smoke and underexpression or absence of folate receptor in SCCs and associated premalignant lesions, are discussed in light of these findings.
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Affiliation(s)
- C J Piyathilake
- Department of Nutrition Sciences, University of Alabama at Birmingham 35294, USA
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Gershoni-Baruch R, Dagan E, Israeli D, Kasinetz L, Kadouri E, Friedman E. Association of the C677T polymorphism in the MTHFR gene with breast and/or ovarian cancer risk in Jewish women. Eur J Cancer 2000; 36:2313-6. [PMID: 11094304 DOI: 10.1016/s0959-8049(00)00306-3] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene is associated with reduced enzyme activity, hyperhomocysteinaemia and increased risk for atherosclerosis in homozygotes. We examined the frequency of this mutation and its association with disease pattern in 491 Jewish women with either sporadic (n = 355; 72%) or hereditary (n = 136; 28%) breast and/or ovarian cancer and in 69 asymptomatic BRCA1/2 mutation carriers, genotyped for the three predominant Jewish founder BRCA1/2 mutations (185delAG, 5382insC and 6174delT). 677T homozygotes were equally distributed among women with sporadic breast and/or ovarian cancer (71/355; 20.0%) and among BRCA1/2 mutation carriers (43/205; 21.0%) (P=non-significant). 677T homozygotes were equally distributed among women diagnosed with breast cancer prior to (22/122; 18.0%) and after 42 years of age (42/243; 17.3%). Among BRCA1/2 carriers, the rate of 677T homozygotes in manifesting cancer (32/136; 23.5%) and asymptomatic individuals (11/69; 15.9%) was not significantly different. The rate of 677T homozygotes (24/72; 33.3%) was higher (P=0.0026) among women with bilateral breast cancer and those with both breast and ovarian carcinoma than among those with unilateral breast cancer (64/365; 17.5%). Differences in morbidity (one versus multiple breast/ovarian tumours) are mainly attributed to 677T homozygosity and partly to BRCA1/2 mutations. Confirmation of these data, namely, that the 677T allele is significantly more common in cases of bilateral breast cancer or combined breast and ovarian cancer would have important clinical implications.
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43
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Gaughan DJ, Barbaux S, Kluijtmans LA, Whitehead AS. The human and mouse methylenetetrahydrofolate reductase (MTHFR) genes: genomic organization, mRNA structure and linkage to the CLCN6 gene. Gene 2000; 257:279-89. [PMID: 11080594 DOI: 10.1016/s0378-1119(00)00392-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Methylenetetrahydrofolate reductase (MTHFR), a pivotal enzyme in folate metabolism, regulates the proportional distribution of one-carbon moieties between cellular methylation reactions and nucleic acid synthesis. The organization of the MTHFR gene and the structure of its mRNA were characterized in human and mouse. There are three mRNA transcripts of 2.8, 7.2 and 9.8 kb in human and two of 3.2 and 7.5 kb in mouse. Northern blot analysis revealed that human MTHFR MRNA is only present at low abundance in most tissues tested. Five kilobases of sequence flanking the 3' end of the human gene were isolated, and polyadenylation sites were defined by 3' RACE. The shorter 2.8 kb transcript and the two larger 7.2 and 9.8 kb transcripts utilize different polyadenylation signal sequences, 629 and 4937 bp downstream of the stop codon, respectively. The two mRNA species in mouse also result from differential polyadenylation. Approximately 7 and 3.5 kb upstream of the human and mouse genes, respectively, were isolated and sequenced. Transcription start sites in human MTHFR were mapped using 5' RACE. The 2.8 and 7.2 kb mRNAs originate from one of two transcription start sites that are 206 and 243 bp upstream of the ATG initiation codon, whereas transcription of the 9.8 kb mRNA is initiated at a start site located 2.8 kb upstream of the translation start codon. The putative MTHFR promoter does not have a TATA box but contains CpG islands and multiple potential Sp1 binding sites. The MTHFR gene was finely mapped to interval 16 of chromosome 1p36.3, a region deleted in many tumors, by establishing a close linkage to CLCN6, a putative chloride channel gene. A novel CA-repeat polymorphism identified within intron 2 of the CLCN6 gene may be useful in assessing loss of heterozygosity in such tumors. The multiple MTHFR mRNA species identified in this report may reflect an underlying complex set of gene regulatory mechanisms acting through an alternative transcription start site and/or polyadenylation signal sequence utilization.
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Affiliation(s)
- D J Gaughan
- Department of Pharmacology and Center for Pharmacogenetics, University of Pennsylvania, Philadelphia, PA 19104, USA
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Ward CM, Acheson N, Seymour LW. Folic acid targeting of protein conjugates into ascites tumour cells from ovarian cancer patients. J Drug Target 2000; 8:119-23. [PMID: 10852343 DOI: 10.3109/10611860008996857] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Despite a wealth of in vitro data describing the use of folic acid for drug and DNA delivery into ovarian cancer cell lines, there have been no reports describing the targeting of such compounds to freshly isolated tumour cells. We have carried out a study to determine the usefulness of folic acid as a targeting ligand for ovarian cancer by measuring the uptake of folic acid-BSA-FITC in tumour cells isolated from the ascitic fluid of ovarian cancer patients. In 7 out of 7 patients we have found folic acid mediated uptake of the fluorescently labelled albumin, with the accumulation (average cell fluorescence) and differential uptake (ratio between receptor mediated and fluid phase uptake) varying between patients. Accumulation of folic acid-albumin FITC occurs in ascites tumour cells expressing the epithelial cell marker EMA, with a significant proportion of EMA negative cells also accumulating the conjugate. There is no correlation between cell cycle and uptake of folic acid-BSA-FITC. These results suggest that folic acid-targeting of therapeutics is a promising approach for the treatment of ovarian cancer.
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Affiliation(s)
- C M Ward
- CRC Institute for Cancer Studies, University of Birmingham, West Midlands, UK.
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45
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Födinger M, Buchmayer H, Heinz G, Papagiannopoulos M, Kletzmayr J, Rasoul-Rockenschaub S, Hörl WH, Sunder-Plassmann G. Effect of MTHFR 1298A-->C and MTHFR 677C-->T genotypes on total homocysteine, folate, and vitamin B(12) plasma concentrations in kdiney graft recipients. J Am Soc Nephrol 2000; 11:1918-1925. [PMID: 11004224 DOI: 10.1681/asn.v11101918] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The effect of 5,10-methylenetetrahydrofolate reductase (MTHFR) 677C-->T and 1298A-->C on total homocysteine (tHcy), folate and vitamin B(12) levels was investigated in 733 kidney graft recipients. The six major genotype combinations were used as grouping variables, and age, gender, BMI, serum creatinine, and creatinine clearance and ln-folate, ln-vitamin B(12), or logarithmus naturalis tHcy (ln-tHcy) were used as covariates in three ANCOVA and multiple stepwise linear regression models. Hyperhomocysteinemia was present in 49.7% of the patients. The allele frequency of MTHFR 677T and 1298C was 0.319 and 0.326. MTHFR genotype and all other variables were significant predictors of ln-tHcy (higher tHcy plasma levels for MTHFR 677TT/1298AA versus all other five genotype groups: P < 0. 05). BMI, creatinine clearance, ln-tHcy, and MTHFR genotype influenced ln-folate (lower folate levels for MTHFR 677TT/1298AA versus all other genotype groups: P < 0.05). Creatinine clearance and ln-tHcy were the only predictors of ln-vitamin B(12) levels. In a prespecified subgroup analysis (n = 496), the MTHFR genotype also influenced tHcy levels and compound heterozygous patients had significantly lower folate levels as compared with MTHFR 677CC/1298AA and 677CC/1298CC. This study shows that the MTHFR 677TT/1298AA and 677CT/1298AC genotypes are significant predictors of tHcy and folate plasma levels.
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Affiliation(s)
- Manuela Födinger
- Department of Laboratory Medicine, Division of Molecular Biology, University of Vienna, Austria
| | - Heidi Buchmayer
- Department of Laboratory Medicine, Division of Molecular Biology, University of Vienna, Austria
| | - Gotfried Heinz
- Department of Medicine II, Division of Cardiology and Angiology, University of Vienna, Austria
| | | | - Josef Kletzmayr
- Department of Medicine III, Division of Nephrology and Dialysis, University of Vienna, Austria
| | | | - Walter H Hörl
- Department of Medicine III, Division of Nephrology and Dialysis, University of Vienna, Austria
| | - Gere Sunder-Plassmann
- Department of Medicine III, Division of Nephrology and Dialysis, University of Vienna, Austria
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Chango A, Boisson F, Barbé F, Quilliot D, Droesch S, Pfister M, Fillon-Emery N, Lambert D, Frémont S, Rosenblatt DS, Nicolas JP. The effect of 677C-->T and 1298A-->C mutations on plasma homocysteine and 5,10-methylenetetrahydrofolate reductase activity in healthy subjects. Br J Nutr 2000; 83:593-6. [PMID: 10911766 DOI: 10.1017/s0007114500000751] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We have studied the effect of common mutations (677C-->T and 1298A-->C) of the methylenetetrahydrofolate reductase (MTHFR) gene in sixty-six healthy French subjects, aged 27-47 years. Serum folate, vitamin B12, and plasma total homocysteine were measured as well as the specific activity of MTHFR in lymphocytes. The frequency of subjects homozygous for the 677TT genotype was 18%, and that of those homozygous for the 1298CC genotype was 12.5%. The frequency of individuals heterozygous for both mutations was 23.5%. The 1298A-->C mutation was associated with decreased MTHFR specific activity in subjects with both 677CC and 677CT genotypes. This activity was 60% for the 677CC/1298AC genotype and 52% for the 677CC/1298CC genotype when compared with the MTHFR specific activity of the 677CC/1298AA genotype. Heterozygotes for both mutations (677CT/1298AC genotype) had 36% of the reference specific activity. Although homocysteine levels in 677TT and 1298CC genotype subjects were higher than for other genotypes, no significant differences were observed among different genotypes. This may be due to high serum folate level in our samples, and suggests that folate therapy may be useful to prevent hyperhomocysteinaemia in homozygous mutant subjects.
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Affiliation(s)
- A Chango
- Laboratoire de Biochimie Médicale et Pédiatrique, INSERM U-308, Nancy, France.
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Abstract
An elevated total homocysteine plasma concentration is associated with an increased morbidity and mortality due to cardiovascular disease in the general population, in patients with renal failure and in recipients of kidney or heart transplants. The fasting or post-methionine loading plasma concentration of total homocysteine is elevated in 50-60% of renal transplant recipients with stable graft function and in the majority of heart transplant recipients. Fasting and post-methionine loading hyperhomocysteinemia can be normalized in virtually all renal transplant patients by a combination of folic acid (5 mg/d), vitamin B6 (50 mg/d) and vitamin B12 (0.4 mg/d). In individuals without renal failure much lower doses of folate and vitamin B12 are able to correct hyperhomocysteinemia. Currently, prospective studies are under way to clarify whether folate and vitamin therapy improves cardiovascular disease morbidity and mortality in the general population and in organ transplant recipients. While population wide screening for and treatment of hyperhomocysteinemia is generally not recommended, treatment of high risk patients, including renal failure patients and kidney and heart transplant recipients, can be considered but still represents an experimental therapy.
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48
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Molecular Biology of Methylenetetrahydrofolate Reductase (MTHFR): Interrelationships with Folic Acid, Homocysteine and Vascular Disease. ACTA ACUST UNITED AC 2000. [DOI: 10.1007/978-94-017-1789-2_16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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49
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Stegmann K, Ziegler A, Ngo ETKM, Kohlschmidt N, Schr�ter B, Ermert A, Koch MC. Linkage disequilibrium of MTHFR genotypes 677C/T-1298A/C in the German population and association studies in probands with neural tube defects(NTD). ACTA ACUST UNITED AC 1999. [DOI: 10.1002/(sici)1096-8628(19991105)87:1<23::aid-ajmg5>3.0.co;2-e] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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50
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Weisberg I, Tran P, Christensen B, Sibani S, Rozen R. A second genetic polymorphism in methylenetetrahydrofolate reductase (MTHFR) associated with decreased enzyme activity. Mol Genet Metab 1998; 64:169-72. [PMID: 9719624 DOI: 10.1006/mgme.1998.2714] [Citation(s) in RCA: 909] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A common mutation in methylenetetrahydrofolate reductase (MTHFR), C677T, results in a thermolabile variant with reduced activity. Homozygous mutant individuals (approximately 10% of North Americans) are predisposed to mild hyperhomocysteinemia, when their folate status is low. This genetic-nutrient interactive effect is believed to increase the risk for neural tube defects and vascular disease. In this communication, we characterize a second common variant in MTHFR (A1298C), an E to A substitution. Homozygosity was observed in approximately 10% of Canadian individuals. This polymorphism was associated with decreased enzyme activity; homozygotes had approximately 60% of control activity in lymphocytes. Heterozygotes for both the C677T and the A1298C mutation, approximately 15% of individuals, had 50-60% of control activity, a value that was lower than that seen in single heterozygotes for the C677T variant. No individuals were homozygous for both mutations. Additional studies of the A1298C mutation, in the absence and presence of the C677T mutation, are warranted, to adequately address the role of this new genetic variant in complex traits. A silent genetic variant, T1317C, was identified in the same exon. It was relatively infrequent (allele frequency 5%) in our study group, but was quite common in a small sample of African individuals (allele frequency 39%).
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Affiliation(s)
- I Weisberg
- Department of Human Genetics, McGill University Health Centre, Montreal, Quebec, H3Z 2Z3, Canada
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