title: Overcoming EGFR T790M-based Tyrosine Kinase Inhibitor Resistance with an Allele-specific DNAzyme.
abstract: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are the main therapeutic agents used to treat non-small-cell lung cancer patients harboring EGFR-activating mutations. However, most of these patients will eventually develop resistance, 50% of which are due to a secondary mutation at T790M in the EGFR. In this paper, we describe the development of an allele-specific DNAzyme, DzT, that can specifically silence EGFR T790M mutant messenger RNA while leaving wild-type EGFR intact. Allele-specific silencing of EGFR T790M expression and downstream signaling by DzT triggered apoptosis in non-small-cell lung cancer cells harboring this mutant. Adding a cholesterol-triethylene glycol group on the 3'-end of DzT (cDzT) improved drug efficacy, increasing inhibitory effect on cell viability from 46 to 79% in T790M/L858R-harboring H1975(TM/LR) non-small-cell lung cancer cells, without loss of allele specificity. Combined treatment with cDzT and BIBW-2992, a second-generation EGFR-tyrosine kinase inhibitor, synergistically inhibited EGFR downstream signaling and suppressed the growth of xenograft tumors derived from H1975(TM/LR) cells. Collectively, these results indicate that the allele-specific DNAzyme, DzT, may provide an alternative treatment for non-small-cell lung cancer that is capable of overcoming EGFR T790M mutant-based tyrosine kinase inhibitor resistance.Molecular Therapy-Nucleic Acids (2014) 3, e150; doi:10.1038/mtna.2014.3; published online 4 March 2014.
authors.affiliation: 1] Taiwan International Graduate Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan [2] Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan [3] Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
authors.forename: Wei-Yun
authors.initials: WY
authors.lastname: Lai
authors.affiliation: Department of Nutrition and Health Sciences, Chang Gung University of Science and Technology, Taoyuan, Taiwan.
authors.forename: Chi-Yuan
authors.initials: CY
authors.lastname: Chen
authors.affiliation: Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
authors.forename: Shuenn-Chen
authors.initials: SC
authors.lastname: Yang
authors.affiliation: Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
authors.forename: Jer-Yuarn
authors.initials: JY
authors.lastname: Wu
authors.affiliation: Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
authors.forename: Cheng-Ju
authors.initials: CJ
authors.lastname: Chang
authors.affiliation: 1] Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan [2] College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Pan-Chyr
authors.initials: PC
authors.lastname: Yang
authors.affiliation: 1] Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan [2] Author deceased.
authors.forename: Konan
authors.initials: K
authors.lastname: Peck