De-methylation of displacement loop of mitochondrial DNA is associated with increased mitochondrial copy number and nicotinamide adenine dinucleotide subunit 2 expression in colorectal cancer

Gao,Jinhang; Wen,Shilei; Zhou,Hongying; Feng,Shi

doi:10.3892/mmr.2015.4256

De-methylation of displacement loop of mitochondrial DNA is associated with increased mitochondrial copy number and nicotinamide adenine dinucleotide subunit 2 expression in colorectal cancer

Authors:
- Jinhang Gao
- Shilei Wen
- Hongying Zhou
- Shi Feng
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Affiliations: Department of Human Anatomy, Academy of Preclinical and Forensic Medicine, West China Medicine College, Sichuan University, Chengdu, Sichuan 610041, P.R. China
Published online on: August 26, 2015 https://doi.org/10.3892/mmr.2015.4256
Pages: 7033-7038

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Abstract

DNA methylation occurs in the displacement loop (D-loop) region of mammals; however, D-loop regions of certain tumor tissue types were found to be de‑methylated. Whether hypomethylation of the D‑loop region is involved in the regulation of the mitochondrial DNA (mtDNA) copy number and nicotinamide adenine dinucleotide subunit 2 (ND‑2) expressions in colorectal cancer has remained elusive. In the present study, the association between methylation status of the D‑loop region, mtDNA copy number and ND‑2 expression was investigated in 65 colorectal cancer specimens and their corresponding non‑cancerous tissues. In addition, a de‑methylation experiment was performed on the Caco‑2 colorectal cancer cell line by using 5‑aza-2'-deoxycytidine (5‑Aza). The methylation rate of the D‑loop region in all 65 colorectal cancer tissues was markedly reduced when compared with that of their corresponding non‑cancerous tissues (13.8 vs. 81.5%; P<0.05). Furthermore, the methylation rate of the D‑loop region in colorectal cancer tissues was markedly decreased in clinicopathological stages III and IV compared with that in clinicopathological stages I and II (7.1 and 0% vs. 25 and 16%; P<0.05). In addition, the mean relative mtDNA copy number and ND‑2 expression in colorectal cancer tissues were increased compared with those in the corresponding non‑cancerous tissues. De‑methylation of the D‑loop region was associated with an elevated mtDNA copy number and an increased ND‑2 expression. Furthermore, the mtDNA copy number and ND‑2 expression in Caco‑2 cells were significantly increased after 5‑Aza treatment. In conclusion, de‑methylation of the D‑loop region is likely to be involved in the regulation of the mtDNA copy number and ND-2 expression.

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1	Siegel R, Desantis C and Jemal A: Colorectal cancer statistics, 2014. CA Cancer J Clin. 64:104–117. 2014. View Article : Google Scholar : PubMed/NCBI
2	Center MM, Jemal A, Smith RA and Ward E: Worldwide variations in colorectal cancer. CA Cancer J Clin. 59:366–378. 2009. View Article : Google Scholar : PubMed/NCBI
3	Grivell LA: Mitochondrial DNA. Small, beautiful and essential. Nature. 341:569–571. 1989. View Article : Google Scholar : PubMed/NCBI
4	Lightowlers RN, Chinnery PF, Turnbull DM and Howell N: Mammalian mitochondrial genetics: Heredity, heteroplasmy and disease. Trends Genet. 13:450–455. 1997. View Article : Google Scholar
5	Zhang G, Qu Y, Dang S, Yang Q, Shi B and Hou P: Variable copy number of mitochondrial DNA (mtDNA) predicts worse prognosis in advanced gastric cancer patients. Diagn Pathol. 8:1732013. View Article : Google Scholar : PubMed/NCBI
6	Cheau-Feng Lin F, Jeng YC, Huang TY, Chi CS, Chou MC and Chin-Shaw Tsai S: Mitochondrial DNA copy number is associated with diagnosis and prognosis of head and neck cancer. Biomarkers. 19:269–274. 2014. View Article : Google Scholar : PubMed/NCBI
7	Feng S, Xiong L, Ji Z, Cheng W and Yang H: Correlation between increased copy number of mitochondrial DNA and clinicopatho-logical stage in colorectal cancer. Oncol Lett. 2:899–903. 2011.
8	Boland ML, Chourasia AH and Macleod KF: Mitochondrial dysfunction in cancer. Front Oncol. 3:2922013. View Article : Google Scholar : PubMed/NCBI
9	Feng S, Xiong L, Ji Z, Cheng W and Yang H: Correlation between increased ND2 expression and demethylated displacement loop of mtDNA in colorectal cancer. Mol Med Rep. 6:125–130. 2012.PubMed/NCBI
10	Bellizzi D, D'Aquila P, Scafone T, Giordano M, Riso V, Riccio A and Passarino G: The control region of mitochondrial DNA shows an unusual CpG and non-CpG methylation pattern. DNA Res. 20:537–547. 2013. View Article : Google Scholar : PubMed/NCBI
11	Roos-Araujo D, Stuart S, Lea RA, Haupt LM and Griffiths LR: Epigenetics and migraine; complex mitochondrial interactions contributing to disease susceptibility. Gene. 543:1–7. 2014. View Article : Google Scholar : PubMed/NCBI
12	Esteller M: CpG island hypermethylation and tumor suppressor genes: A booming present, a brighter future. Oncogene. 21:5427–5440. 2002. View Article : Google Scholar : PubMed/NCBI
13	Mates IN, Jinga V, Csiki IE, Mates D, Dinu D, Constantin A and Jinga M: Single nucleotide polymorphisms in colorectal cancer: associations with tumor site and TNM stage. J Gastrointestin Liver Dis. 21:45–52. 2012.PubMed/NCBI
14	Matsubara N: Epigenetic regulation and colorectal cancer. Dis Colon Rectum. 55:96–104. 2012. View Article : Google Scholar
15	Zhang R, Zhang F, Wang C, Wang S, Shiao YH and Guo Z: Identification of sequence polymorphism in the D-Loop region of mitochondrial DNA as a risk factor for hepatocellular carcinoma with distinct etiology. J Exp Clin Cancer Res. 29:1302010. View Article : Google Scholar : PubMed/NCBI
16	Ylikallio E, Tyynismaa H, Tsutsui H, Ide T and Suomalainen A: High mitochondrial DNA copy number has detrimental effects in mice. Hum Mol Genet. 19:2695–2705. 2010. View Article : Google Scholar : PubMed/NCBI
17	Penta JS, Johnson FM, Wachsman JT and Copeland WC: Mitochondrial DNA in human malignancy. Mutat Res. 488:119–133. 2001. View Article : Google Scholar : PubMed/NCBI
18	Zhang J, Guo Z, Bai Y, Cui L, Zhang S and Xu J: Identification of sequence polymorphisms in the displacement loop region of mitochondrial DNA as a risk factor for renal cell carcinoma. Biomed Rep. 1:563–566. 2013.
19	Tommasi S, Favia P, Weigl S, Bianco A, Pilato B, Russo L, Paradiso A and Petruzzella V: Mitochondrial DNA variants and risk of familial breast cancer: An exploratory study. Int J Oncol. 44:1691–1698. 2014.PubMed/NCBI
20	Maniura-Weber K, Goffart S, Garstka HL, Montoya J and Wiesner RJ: Transient overexpression of mitochondrial transcription factor A (TFAM) is sufficient to stimulate mitochondrial DNA transcription, but not sufficient to increase mtDNA copy number in cultured cells. Nucleic Acids Res. 32:6015–6027. 2004. View Article : Google Scholar : PubMed/NCBI
21	Kurita T, Izumi H, Kagami S, Kawagoe T, Toki N, Matsuura Y, Hachisuga T and Kohno K: Mitochondrial transcription factor A regulates BCL2L1 gene expression and is a prognostic factor in serous ovarian cancer. Cancer Sci. 103:239–444. 2012. View Article : Google Scholar
22	LeBleu VS, O'Connell JT, Gonzalez Herrera KN, Wikman H, Pantel K, Haigis MC, de Carvalho FM, Damascena A, Domingos Chinen LT, Rocha RM, et al: PGC-1α mediates mitochondrial biogenesis and oxidative phosphorylation in cancer cells to promote metastasis. Nat Cell Biol. 16:992–1003. 2014. View Article : Google Scholar
23	Lim SH, Wu L, Kiew LV, Chung LY, Burgess K and Lee HB: Rosamines targeting the cancer oxidative phosphorylation pathway. PloS one. 9:e829342014. View Article : Google Scholar : PubMed/NCBI