Activation of the IGF1R pathway potentially mediates acquired resistance to mutant-selective 3rd-generation EGF receptor tyrosine kinase inhibitors in advanced non-small cell lung cancer
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Ji Hyun Park1, Yun Jung Choi2,3, Seon Ye Kim2,3, Jung-Eun Lee2,3, Ki Jung Sung2,3, Sojung Park2, Woo Sung Kim2, Joon Seon Song4, Chang-Min Choi1,2, Young Hoon Sung3,5, Jin Kyung Rho3,5, Jae Cheol Lee1
1Department of Oncology, Asan Medical Center, University of Ulsan, College of Medicine, Seoul, Korea
2Department of Pulmonology and Critical Care Medicine, Asan Medical Center, University of Ulsan, College of Medicine, Seoul, Korea
3Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan, College of Medicine, Seoul, Korea
4Department of Pathology, Asan Medical Center, University of Ulsan, College of Medicine, Seoul, Korea
5Department of Convergence Medicine, Asan Medical Center, University of Ulsan, College of Medicine, Seoul, Korea
Jin Kyung Rho, e-mail: [email protected]
Jae Cheol Lee, e-mail: [email protected]
Keywords: 3rd generation, EGFR-TKI, IGF1R, resistance, NSCLC
Received: December 07, 2015 Accepted: February 21, 2016 Published: March 09, 2016
Mutant-selective, 3rd-generation EGFR-TKIs were recently developed to control lung cancer cells harboring T790M-mediated resistance. However, the development of resistance to these novel drugs seems inevitable. Thus, we investigated the mechanism of acquired resistance to the mutant-selective EGFR-TKI WZ4002. We established five WZ4002-resistant cells, derived from cells harboring both EGFR and T790M mutations by long-term exposure to increasing doses of WZ4002. Compared with the parental cells, all resistant cells showed 10–100-folds higher resistance to WZ4002, as well as cross-resistance to other mutant-selective inhibitors. Among them, three resistant cells (HCC827/WR, PC-9/WR and H1975/WR) showed dependency on EGFR signaling, but two other cells (PC-9/GR/WR and PC-9/ER/WR) were not. Notably, insulin-like growth factor-1 receptor (IGF1R) was aberrantly activated in PC-9/GR/WR cells in phospho-receptor tyrosine kinase array, consistently accompanied by loss of IGF binding protein-3 (IGFBP3). Down-regulation of IGF1R by shRNA, as well as inhibition of IGF1R activity either by AG-1024 (a small molecule IGF1R inhibitor) or BI 836845 (a monoclonal anti-IGF1/2 blocking antibody), restored the sensitivity to WZ4002 both in vitro and xenograft. Taken together, these results suggest that activation of the IGF1R pathway associated with IGFBP3 loss can induce an acquired resistance to the mutant-selective EGFR-TKI, WZ4002. Therefore, a combined therapy of IGF1R inhibitors and mutant-selective EGFR-TKIs might be a viable treatment strategy for overcoming acquired resistance.
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