Somatic mitochondrial DNA mutations in cancer escape purifying selection and high pathogenicity mutations lead to the oncocytic phenotype: pathogenicity analysis of reported somatic mtDNA mutations in tumorsReport as inadecuate




Somatic mitochondrial DNA mutations in cancer escape purifying selection and high pathogenicity mutations lead to the oncocytic phenotype: pathogenicity analysis of reported somatic mtDNA mutations in tumors - Download this document for free, or read online. Document in PDF available to download.

BMC Cancer

, 12:53

Systems biology, post-genomic analysis and emerging technologies

Abstract

BackgroundThe presence of somatic mitochondrial DNA mtDNA mutations in cancer cells has been interpreted in controversial ways, ranging from random neutral accumulation of mutations, to positive selection for high pathogenicity, or conversely to purifying selection against high pathogenicity variants as occurs at the population level.

MethodsHere we evaluated the predicted pathogenicity of somatic mtDNA mutations described in cancer and compare these to the distribution of variations observed in the global human population and all possible protein variations that could occur in human mtDNA. We focus on oncocytic tumors, which are clearly associated with mitochondrial dysfunction. The protein variant pathogenicity was predicted using two computational methods, MutPred and SNPsandGO.

ResultsThe pathogenicity score of the somatic mtDNA variants were significantly higher in oncocytic tumors compared to non-oncocytic tumors. Variations in subunits of Complex I of the electron transfer chain were significantly more common in tumors with the oncocytic phenotype, while variations in Complex V subunits were significantly more common in non-oncocytic tumors.

ConclusionsOur results show that the somatic mtDNA mutations reported over all tumors are indistinguishable from a random selection from the set of all possible amino acid variations, and have therefore escaped the effects of purifying selection that act strongly at the population level. We show that the pathogenicity of somatic mtDNA mutations is a determining factor for the oncocytic phenotype. The opposite associations of the Complex I and Complex V variants with the oncocytic and non-oncocytic tumors implies that low mitochondrial membrane potential may play an important role in determining the oncocytic phenotype.

AbbreviationsmtDNAMitochondrial DNA

OXPHOSOxidative phosphorylation: HmtDB: Human mitochondrial database

rCRSRevised Cambridge reference sequence

OMIMOnline mendelian inheritance in man

HIF1αHypoxia inducible factor-1α

VEGFVascular endothelial growth factor

Electronic supplementary materialThe online version of this article doi:10.1186-1471-2407-12-53 contains supplementary material, which is available to authorized users.

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Author: Luísa Pereira - Pedro Soares - Valdemar Máximo - David C Samuels

Source: https://link.springer.com/







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