TY - JOUR AB - AXL receptor tyrosine kinase ligand (AXL), a tyrosine kinase receptor that is commonly overexpressed in numerous types of cancer, significantly promotes drug resistance and metastasis in tumor cells. Inhibition of the AXL/growth arrest‑specific 6 (Gas6) signaling pathway is emerging as a potential anticancer therapeutic strategy. In the present study, on the basis of the three‑dimensional complex structure of AXL/Gas6, the critical residues (E56, E59 and T77) in AXL binding to Gas6 were determined using computer graphics analysis and the distance geometry method. Subsequently, four‑variant AXL‑ECD‑Fc‑M1 (G32S, D87G, V92A and G127R) and AXL‑ECD‑Fc‑M2 (G32A, D87A, V92A and G127A) were predicted as high‑affinity mutants; AXL‑ECD‑Fc‑M3 (E56R and T77R) and AXL‑ECD‑Fc‑M4 (E59R and T77R) were predicted as low‑affinity mutants. The results of the present study revealed that the half‑maximal effect concentrations of AXL‑ECD‑Fc‑M1 and AXL‑ECD‑Fc‑M2 were ~0.141 and 0.375 µg/ml, respectively, whereas that of the wild‑type protein (AXL‑ECD‑Fc‑WT) was 0.514 µg/ml. Furthermore, adding the high‑affinity mutants into culture medium to capture free Gas6 significantly inhibited AXL/Gas6 binding and thus blocked the downstream signaling pathway. In addition, the high‑affinity mutants effectively suppressed the migration and metastasis of SKOV3 and A549 cells. Conversely, compared with AXL‑ECD‑Fc‑WT, the low‑affinity AXL mutants AXL‑ECD‑Fc‑M3 and AXL‑ECD‑Fc‑M4 lost all inhibitory activities. These findings highlight AXL as a potential therapeutic target and demonstrated that the key residues E56, E59 and T77 may be crucial sites for abolishing the activity of the AXL/Gas6 pathway in cancer therapy. AD - State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, P.R. China Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China Beijing Key Laboratory of Therapeutic Gene Engineering Antibody, Beijing 100850, P.R. China Joint National Laboratory for Antibody Drug Engineering, Henan University, Zhengzhou, Henan 475004, P.R. China AU - Duan,Yanting AU - Hu,Bo AU - Qiao,Chunxia AU - Luo,Longlong AU - Li,Xinying AU - Wang,Jing AU - Liu,Hao AU - Zhou,Tingting AU - Shen,Beifen AU - Lv,Ming AU - Feng,Jiannan DA - 2019/06/01 DO - 10.3892/ol.2019.10255 EP - 5792 IS - 6 JO - Oncol Lett KW - AXL receptor tyrosine kinase ligand/growth arrest specific 6 pathway distance geometry Fc fusion protein cell migration cancer therapy PY - 2019 SN - 1792-1074 1792-1082 SP - 5784 ST - Engineered AXL‑ECD‑Fc variants that abolish the AXL/Gas6 interaction suppress tumor cell migration T2 - Oncology Letters TI - Engineered AXL‑ECD‑Fc variants that abolish the AXL/Gas6 interaction suppress tumor cell migration UR - https://doi.org/10.3892/ol.2019.10255 VL - 17 ER -