title: Profiling global kinome signatures of the radioresistant MCF-7/C6 breast cancer cells using MRM-based targeted proteomics.
abstract: Ionizing radiation is widely used in cancer therapy; however, cancer cells often develop radioresistance, which compromises the efficacy of cancer radiation therapy. Quantitative assessment of the alteration of the entire kinome in radioresistant cancer cells relative to their radiosensitive counterparts may provide important knowledge to define the mechanism(s) underlying tumor adaptive radioresistance and uncover novel target(s) for effective prevention and treatment of tumor radioresistance. By employing a scheduled multiple-reaction monitoring analysis in conjunction with isotope-coded ATP affinity probes, we assessed the global kinome of radioresistant MCF-7/C6 cells and their parental MCF-7 human breast cancer cells. We rigorously quantified 120 kinases, of which (1)/3 exhibited significant differences in expression levels or ATP binding affinities. Several kinases involved in cell cycle progression and DNA damage response were found to be overexpressed or hyperactivated, including checkpoint kinase 1 (CHK1), cyclin-dependent kinases 1 and 2 (CDK1 and CDK2), and the catalytic subunit of DNA-dependent protein kinase. The elevated expression of CHK1, CDK1, and CDK2 in MCF-7/C6 cells was further validated by Western blot analysis. Thus, the altered kinome profile of radioresistant MCF-7/C6 cells suggests the involvement of kinases on cell cycle progression and DNA repair in tumor adaptive radioresistance. The unique kinome profiling results also afforded potential effective targets for resensitizing radioresistant cancer cells and counteracting deleterious effects of ionizing radiation exposure.
authors.affiliation: Environmental Toxicology Graduate Program and ‡Department of Chemistry, University of California , Riverside, California 92521-0403, United States.
authors.forename: Lei
authors.initials: L
authors.lastname: Guo
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Xiao
authors.forename: Ming
authors.initials: M
authors.lastname: Fan
authors.forename: Jian Jian
authors.initials: JJ
authors.lastname: Li
authors.forename: Yinsheng
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D001943:Breast Neoplasms; D005260:Female; D063990:Gene Ontology; D006801:Humans; D061986:MCF-7 Cells; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D020543:Proteome / Q000737:chemistry / Q000378:metabolism*; D040901:Proteomics; D011836:Radiation Tolerance; D053719:Tandem Mass Spectrometry
chemical_list: D020543:Proteome; D011494:Protein Kinases
keywords: MRM; breast cancer; ionizing radiation; isotope-coded ATP affinity probe; protein kinases; radioresistance