1. Selective targeting of c-Abl via a cryptic mitochondrial targeting signal activated by cellular redox status in leukemic and breast cancer cells
- Author
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Samuel D. Despres, Carol S. Lim, Jonathan E. Constance, and Akemi Nishida
- Subjects
Programmed cell death ,Recombinant Fusion Proteins ,Molecular Sequence Data ,Pharmaceutical Science ,Gene Expression ,Mammary Neoplasms, Animal ,Mitochondrion ,Biology ,medicine.disease_cause ,Article ,Mice ,hemic and lymphatic diseases ,Cell Line, Tumor ,Chlorocebus aethiops ,medicine ,Animals ,Humans ,Pharmacology (medical) ,Amino Acid Sequence ,Proto-Oncogene Proteins c-abl ,neoplasms ,Pharmacology ,chemistry.chemical_classification ,Reactive oxygen species ,ABL ,Leukemia ,Cell Death ,Organic Chemistry ,Cell biology ,Mitochondria ,Oxidative Stress ,Protein Transport ,chemistry ,Apoptosis ,Cancer cell ,COS Cells ,Molecular Medicine ,Female ,Reactive Oxygen Species ,Tyrosine kinase ,Oxidative stress ,Biotechnology - Abstract
The tyrosine kinase c-Abl localizes to the mitochondria under cell stress conditions and promotes apoptosis. However, c-Abl has not been directly targeted to the mitochondria. Fusing c-Abl to a mitochondrial translocation signal (MTS) that is activated by reactive oxygen species (ROS) will selectively target the mitochondria of cancer cells exhibiting an elevated ROS phenotype. Mitochondrially targeted c-Abl will thereby induce malignant cell death.Confocal microscopy was used to determine mitochondrial colocalization of ectopically expressed c-Abl-EGFP/cMTS fusion across three cell lines (K562, Cos-7, and 1471.1) with varying levels of basal (and pharmacologically modulated) ROS. ROS were quantified by indicator dye assay. The functional consequences of mitochondrial c-Abl were assessed by DNA accessibility to 7-AAD using flow cytometry.The cMTS and cMTS/c-Abl fusions colocalized to the mitochondria in leukemic (K562) and breast (1471.1) cancer phenotypes (but not Cos-7 fibroblasts) in a ROS and PKC dependent manner.We confirm and extend oxidative stress activated translocation of the cMTS by demonstrating that the cMTS and Abl/cMTS fusion selectively target the mitochondria of K562 leukemia and mammary adenocarcinoma 1471.1 cells. c-Abl induced K562 leukemia cell death when targeted to the matrix but not the outer membrane of the mitochondria.
- Published
- 2012