Overcoming EGFR T790M-based Tyrosine Kinase Inhibitor Resistance with an Allele-specific DNAzyme

Wei-Yun Lai; Chi-Yuan Chen; Shuenn-Chen Yang; Jer-Yuarn Wu; Cheng-Ju Chang; Pan-Chyr Yang; Konan Peck

doi:10.1038/mtna.2014.3

Overcoming EGFR T790M-based Tyrosine Kinase Inhibitor Resistance with an Allele-specific DNAzyme

Mol Ther Nucleic Acids. 2014 Mar 4;3(3):e150. doi: 10.1038/mtna.2014.3.

Authors

Wei-Yun Lai¹, Chi-Yuan Chen², Shuenn-Chen Yang³, Jer-Yuarn Wu³, Cheng-Ju Chang³, Pan-Chyr Yang⁴, Konan Peck⁵

Affiliations

¹ 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.
² Department of Nutrition and Health Sciences, Chang Gung University of Science and Technology, Taoyuan, Taiwan.
³ Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
⁴ 1] Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan [2] College of Medicine, National Taiwan University, Taipei, Taiwan.
⁵ 1] Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan [2] Author deceased.

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.