Abstract 4802: Functional analysis of cancer associated mitochondrial genome alterations

Abstract

Abstract It is well documented that a variety of alterations can occur in the mitochondrial genome during human tumor development. These alterations often correlate with cancer phenotypes like treatment resistance and metastasis. Alterations to the mitochondrial genome may therefore be a biomarker for early detection, prognosis and/or predictor of therapeutic sensitivity. However, a method to easily and quickly create isogenic populations of human cells with mitochondrial genome specific alterations is not available. To combat this, we have developed a technology using transient expression of mitochondria targeted TAL domain nickases and TAL endonucleases (TALENs). This the first reliable method to introduce specific mutations into the mitochondrial genome of mammalian cells. We have efficiently induced mtDNA deletions in zebrafish embryos, human and mouse cell lines. In mouse NIH3T3 fibroblasts, we deleted a mitochondrial genome region corresponding to the same disease sequence seen in the human Kearns-Sayre Syndrome (KSS). The deletion resulted in a measurable phenotype including decreased mitochondria basal respiration, ATP production and maximal respiration. We are expanding this work by engineering targeted and precise mtDNA deletions in conjunction with known cancer initiating nuclear mutations in mammalian cells, as well as systemically in mice. These tools will allow us to determine the effect mitochondrial alterations have on the transformation of cancer cells harboring known cancer causing nuclear mutations. We are also developing an inducible system for expressing mitoTALENs, making it possible to create “conditional” loss of function mutations in mitochondrial genes in human cell lines, including induced pluripotent stem cells (iPSCs). This inducible model system will be highly useful in settings where the mitochondrial deletion may cause a selective disadvantage during early cellular differentiation. Citation Format: Neil Otto. Functional analysis of cancer associated mitochondrial genome alterations [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4802.