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Shen J, Wan J, Song R, Zhao H. Peripheral blood mitochondrial DNA copy number, length heteroplasmy and breast cancer risk: a replication study. Carcinogenesis 2015; 36:1307-13. [PMID: 26363030 DOI: 10.1093/carcin/bgv130] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 08/28/2015] [Indexed: 01/31/2023] Open
Abstract
Oxidative stress has consistently been linked to breast carcinogenesis, and mitochondria play a significant role in regulating reactive oxygen species generation. In our previous study, we found that increased levels of mitochondrial DNA (mtDNA) copy number and the presence of mitochondrial length heteroplasmies in the hypervariable (HV) regions 1 and 2 (HV1 and HV2) in peripheral blood are associated with increased risk of breast cancer. In current study with 1000 breast cancer cases and 1000 healthy controls, we intended to replicate our previous findings. Overall, levels of mtDNA copy number were significantly higher in breast cancer cases than healthy controls (mean: 1.17 versus 0.94, P < 0.001). In the multivariate linear regression analysis, increased mtDNA copy number levels were associated with a 1.32-fold increased risk of breast cancer [adjusted odds ratio (OR) = 1.32, 95% confidence interval (CI) = 1.15-1.67]. Breast cancer cases were more likely to have HV1 and HV2 region length heteroplasmies than healthy controls (P < 0.001, respectively). The existence of HV1 and HV2 length heteroplasmies was associated with 2.01- and 1.63-folds increased risk of breast cancer (for HV1: OR = 2.01, 95% CI = 1.66-2.42; for HV2: OR = 1.63, 95% CI = 1.34-1.92). Additionally, joint effects among mtDNA copy number, HV1 and HV2 length heteroplasmies were observed. Our results are consistent with our previous findings and further support the roles of mtDNA copy number and mtDNA length heteroplasmies that may play in the development of breast cancer.
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Affiliation(s)
- Jie Shen
- Department of Epidemiology, The University of Texas MD Anderson Cancer Center, 1155 Pressler Street, Houston, TX 77030, USA
| | - Jie Wan
- Department of Epidemiology, The University of Texas MD Anderson Cancer Center, 1155 Pressler Street, Houston, TX 77030, USA
| | - Renduo Song
- Department of Epidemiology, The University of Texas MD Anderson Cancer Center, 1155 Pressler Street, Houston, TX 77030, USA
| | - Hua Zhao
- Department of Epidemiology, The University of Texas MD Anderson Cancer Center, 1155 Pressler Street, Houston, TX 77030, USA
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Naue J, Hörer S, Sänger T, Strobl C, Hatzer-Grubwieser P, Parson W, Lutz-Bonengel S. Evidence for frequent and tissue-specific sequence heteroplasmy in human mitochondrial DNA. Mitochondrion 2014; 20:82-94. [PMID: 25526677 DOI: 10.1016/j.mito.2014.12.002] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 12/02/2014] [Accepted: 12/09/2014] [Indexed: 10/24/2022]
Abstract
Mitochondrial point heteroplasmy is a common event observed not only in patients with mitochondrial diseases but also in healthy individuals. We here report a comprehensive investigation of heteroplasmy occurrence in human including the whole mitochondrial control region from nine different tissue types of 100 individuals. Sanger sequencing was used as a standard method and results were supported by cloning, minisequencing, and massively parallel sequencing. Only 12% of all individuals showed no heteroplasmy, whereas 88% showed at least one heteroplasmic position within the investigated tissues. In 66% of individuals up to 8 positions were affected. The highest relative number of heteroplasmies was detected in muscle and liver (79%, 69%), followed by brain, hair, and heart (36.7%-30.2%). Lower percentages were observed in bone, blood, lung, and buccal cells (19.8%-16.2%). Accumulation of position-specific heteroplasmies was found in muscle (positions 64, 72, 73, 189, and 408), liver (position 72) and brain (partial deletion at position 71). Deeper analysis of these specific positions in muscle revealed a non-random appearance and position-specific dependency on age. MtDNA heteroplasmy frequency and its potential functional importance have been underestimated in the past and its occurrence is ubiquitous and dependent at least on age, tissue, and position-specific mutation rates.
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Affiliation(s)
- Jana Naue
- Institute of Legal Medicine, Freiburg University Medical Center, Albertstrasse 9, D-79104 Freiburg, Germany; Faculty of Biology, University of Freiburg, Schaenzlestrasse 1, D-79104 Freiburg, Germany.
| | - Steffen Hörer
- Institute of Legal Medicine, Freiburg University Medical Center, Albertstrasse 9, D-79104 Freiburg, Germany.
| | - Timo Sänger
- Institute of Legal Medicine, Freiburg University Medical Center, Albertstrasse 9, D-79104 Freiburg, Germany.
| | - Christina Strobl
- Institute of Legal Medicine, Innsbruck Medical University, Muellerstrasse 44, A-6020 Innsbruck, Austria.
| | - Petra Hatzer-Grubwieser
- Institute of Legal Medicine, Innsbruck Medical University, Muellerstrasse 44, A-6020 Innsbruck, Austria.
| | - Walther Parson
- Institute of Legal Medicine, Innsbruck Medical University, Muellerstrasse 44, A-6020 Innsbruck, Austria; Penn State Eberly College of Science, University Park, PA, USA.
| | - Sabine Lutz-Bonengel
- Institute of Legal Medicine, Freiburg University Medical Center, Albertstrasse 9, D-79104 Freiburg, Germany.
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Calatayud M, Ramos A, Santos C, Aluja MP. Primer effect in the detection of mitochondrial DNA point heteroplasmy by automated sequencing. ACTA ACUST UNITED AC 2013; 24:303-11. [PMID: 23350969 DOI: 10.3109/19401736.2012.760072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The correct detection of mitochondrial DNA (mtDNA) heteroplasmy by automated sequencing presents methodological constraints. The main goals of this study are to investigate the effect of sense and distance of primers in heteroplasmy detection and to test if there are differences in the accurate determination of heteroplasmy involving transitions or transversions. A gradient of the heteroplasmy levels was generated for mtDNA positions 9477 (transition G/A) and 15,452 (transversion C/A). Amplification and subsequent sequencing with forward and reverse primers, situated at 550 and 150 bp from the heteroplasmic positions, were performed. Our data provide evidence that there is a significant difference between the use of forward and reverse primers. The forward primer is the primer that seems to give a better approximation to the real proportion of the variants. No significant differences were found concerning the distance at which the sequencing primers were placed neither between the analysis of transitions and transversions. The data collected in this study are a starting point that allows to glimpse the importance of the sequencing primers in the accurate detection of point heteroplasmy, providing additional insight into the overall automated sequencing strategy.
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Affiliation(s)
- Marta Calatayud
- Unitat d'Antropologia Biològica, Departament BABVE, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain
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Tzen CY, Mau BL, Wu TY. ND4 mutation in transitional cell carcinoma: Does mitochondrial mutation occur before tumorigenesis? Mitochondrion 2007; 7:273-8. [PMID: 17509949 DOI: 10.1016/j.mito.2007.04.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2006] [Revised: 02/27/2007] [Accepted: 04/17/2007] [Indexed: 10/23/2022]
Abstract
To investigate how mitochondrial mutation occurs in cancers, we analyzed ND4 mutation in 53 transitional cell carcinomas (TCCs) of the upper urinary tract and the normal counterpart (perirenal soft tissue). Three methods, i.e., DNA sequencing, restriction fragment length polymorphism (RFLP), and denaturing high-performance liquid chromatography (DHPLC), were employed because of their different sensitive of detecting mutation. The results of sequencing and RFLP showed that ND4 mutations were only found in 24.5% (13/53) of tumor. However, 11 of these mutations could also be identified in the normal tissue by DHPLC, indicating that most mitochondrial mutations identified in tumors preexist as minor components, which are too low in quantity to be detected by less sensitive methods such as DNA sequencing. The result suggests that mtDNA mutation occurs before tumorigenesis and become apparent in cancer cells.
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Affiliation(s)
- Chin-Yuan Tzen
- Department of Pathology, Mackay Memorial Hospital, Taipei, Taiwan.
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