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EPHA2 blockade reverses acquired resistance to afatinib induced by EPHA2‐mediated MAPK pathway activation in gastric cancer cells and avatar mice
Author(s) -
Chen Zuhua,
Liu Zhentao,
Zhang Mengqi,
Huang Wenwen,
Li Zhongwu,
Wang Shubin,
Zhang Cheng,
Dong Bin,
Gao Jing,
Shen Lin
Publication year - 2019
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.32313
Subject(s) - afatinib , cancer research , pi3k/akt/mtor pathway , protein kinase b , mapk/erk pathway , medicine , lapatinib , pharmacology , cancer , biology , kinase , signal transduction , erlotinib , epidermal growth factor receptor , microbiology and biotechnology , trastuzumab , breast cancer
Afatinib is a pan‐HER inhibitor approved for specific types of lung cancer. We explored antitumor activity, predictive biomarkers and the potential mechanisms underlying antitumor effect and acquired resistance of afatinib in gastric cancer (GC) in vitro and in vivo . Five human GC cell lines and eight patient‐derived xenograft (PDX) models with clear molecular profiling were used to evaluate the antitumor activity and mechanisms of afatinib. The ErbB family and downstream PI3K/AKT/mTOR and mitogen‐activated protein kinase (MAPK) pathways were evaluated before and after afatinib treatment. An afatinib‐resistant PDX model was established to explore both the potential mechanisms of drug resistance and reversal strategies. We found that afatinib exerted a strong tumor suppression in EGFR/HER2 highly amplified (copy number >6) or overexpressed (IHC 3+) PDX models and a moderate tumor suppression in EGFR/HER2 moderately expressed (IHC 2+) PDX models. Afatinib selectively inhibited the proliferation of HER2 highly amplified GC cells in a dose‐dependent manner in vitro . Afatinib also exerted its antitumor effect by inducing cell apoptosis and cell arrest at G1 phase. Diminished activation of the ErbB family and downstream PI3K/AKT/mTOR and MAPK pathways was also observed. Erythropoietin‐producing hepatocellular receptor A2 (EPHA2) upregulation and phosphorylation might be involved in afatinib‐acquired resistance, and EPHA2 blockade could restore afatinib sensitivity. GC patients with amplification (copy number >6) or overexpression (IHC 3+) of EGFR/HER2 were most likely to benefit from afatinib treatment and EPHA2 blockade reversed acquired resistance to afatinib treatment, which could provide solid evidences for future clinical trials.