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Enhanced tumorigenicity by mitochondrial DNA mild mutations

2015; Impact Journals LLC; Volume: 6; Issue: 15 Linguagem: Inglês

10.18632/oncotarget.3698

1949-2553

Alberto Cruz‐Bermúdez, Carmen G. Vallejo, Ramiro J. Vicente-Blanco, M. Esther Gallardo, Miguel Ángel Fernández‐Moreno, Miguel Quintanilla, Rafael Garesse,

ATP Synthase and ATPases Research

// Alberto Cruz-Bermúdez 1,2,3 , Carmen G. Vallejo 1 , Ramiro J. Vicente-Blanco 1,2 , María Esther Gallardo 1,2,3 , Miguel Ángel Fernández-Moreno 1,2,3 , Miguel Quintanilla 1,4 and Rafael Garesse 1,2,3 1 Instituto de Investigaciones Biomédicas "Alberto Sols", Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid (UAM), Madrid, Spain 2 Departamento de Bioquímica and Centro de Investigación Biomédica en Red en Enfermedades Raras (CIBERER), Facultad de Medicina, UAM, Madrid, Spain 3 Instituto de Investigación Sanitaria Hospital 12 de Octubre (i+12), Madrid, Spain 4 Instituto de Investigación Hospital Universitario La Paz (IdiPAZ), Madrid, Spain Correspondence to: Miguel Quintanilla, email: // Rafael Garesse, email: // Keywords : cancer, mitochondria, mtDNA mutations, LHON, retrograde signaling Received : January 14, 2015 Accepted : March 02, 2015 Published : March 30, 2015 Abstract To understand how mitochondria are involved in malignant transformation we have generated a collection of transmitochondrial cybrid cell lines on the same nuclear background (143B) but with mutant mitochondrial DNA (mtDNA) variants with different degrees of pathogenicity. These include the severe mutation in the tRNA Lys gene, m.8363G>A, and the three milder yet prevalent Leber's hereditary optic neuropathy (LHON) mutations in the MT-ND1 (m.3460G>A), MT-ND4 (m.11778G>A) and MT-ND6 (m.14484T>C) mitochondrial genes. We found that 143B ρ 0 cells devoid of mtDNA and cybrids harboring wild type mtDNA or that causing severe mitochondrial dysfunction do not produce tumors when injected in nude mice. By contrast cybrids containing mild mutant mtDNAs exhibit different tumorigenic capacities, depending on OXPHOS dysfunction. The differences in tumorigenicity correlate with an enhanced resistance to apoptosis and high levels of NOX expression. However, the final capacity of the different cybrid cell lines to generate tumors is most likely a consequence of a complex array of pro-oncogenic and anti-oncogenic factors associated with mitochondrial dysfunction. Our results demonstrate the essential role of mtDNA in tumorigenesis and explain the numerous and varied mtDNA mutations found in human tumors, most of which give rise to mild mitochondrial dysfunction.