Establishment of a Conditional Transgenic Mouse Model Recapitulating EML4-ALK-Positive Human Non-Small Cell Lung Cancer.
Anaplastic lymphoma receptor tyrosine kinase gene (ALK) fusion is a distinct molecular subclassification of NSCLC that is targeted by anaplastic lymphoma kinase (ALK) inhibitors. We established a transgenic mouse model that expresses tumors highly resembling human NSCLC harboring echinoderm microtubule associated protein like 4 gene (EML)-ALK fusion. We aimed to test an EML4-ALK transgenic mouse model as a platform for assessing the efficacy of ALK inhibitors and examining mechanisms of acquired resistance to ALK inhibitors.



Transgenic mouse lines harboring LoxP-STOP-LoxP-FLAGS-tagged human EML4-ALK (variant 1) transgene was established by using C57BL/6N mice. The transgenic mouse model with highly lung-specific, inducible expression of echinoderm microtubule associated protein like 4-ALK fusion protein was established by crossing the EML4-ALK transgenic mice with mice expressing Cre-estrogen receptor fusion protein under the control of surfactant protein C gene (SPC). Expression of EML4-ALK transgene was induced by intraperitoneally injecting mice with tamoxifen. When the lung tumor of the mice treated with the ALK inhibitor crizotinib for 2 weeks was measured, tumor shrinkage was observed.



EML4-ALK tumor developed after 1 week of tamoxifen treatment. Echinoderm microtubule associated protein like 4-ALK was strongly expressed in the lung but not in other organs. ALK and FLAGS expressions were observed by immunohistochemistry. Treatment of EML4-ALK tumor-bearing mice with crizotinib for 2 weeks induced dramatic shrinkage of tumors with no signs of toxicity. Furthermore, prolonged treatment with crizotinib led to acquired resistance in tumors, resulting in regrowth and disease progression. The resistant tumor nodules revealed acquired ALK G1202R mutations.



An EML4-ALK transgenic mouse model for study of drug resistance was successfully established with short duration of tumorigenesis. This model should be a strong preclinical model for testing efficacy of ALK TKIs, providing a useful tool for investigating the mechanisms of acquired resistance and pursuing novel treatment strategies in ALK-positive lung cancer.
Yonsei Cancer Research Institute, JE-UK Laboratory of Molecular Cancer Therapeutics, Seoul, Republic of Korea.
Kyoung Ho
KH
Pyo
Division of Medical Oncology, Department of Internal Medicine, CHA Bundang Medical Center, Seongnam, Kyeonggi-do, Republic of Korea; Division of Medical Oncology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea.
Sun Min
SM
Lim
Division of Medical Oncology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea.
Hye Ryun
HR
Kim
Department of Convergence Medicine, University of Ulsan College of Medicine and Asan Institute for Life Sciences, Asan Medical Center, Seoul, Republic of Korea.
Young Hoon
YH
Sung
Yonsei Cancer Research Institute, JE-UK Laboratory of Molecular Cancer Therapeutics, Seoul, Republic of Korea.
Mi Ran
MR
Yun
Yonsei Cancer Research Institute, JE-UK Laboratory of Molecular Cancer Therapeutics, Seoul, Republic of Korea.
Sung-Moo
SM
Kim
Yonsei Cancer Research Institute, JE-UK Laboratory of Molecular Cancer Therapeutics, Seoul, Republic of Korea.
Hwan
H
Kim
Yonsei Cancer Research Institute, JE-UK Laboratory of Molecular Cancer Therapeutics, Seoul, Republic of Korea.
Han Na
HN
Kang
Yonsei Cancer Research Institute, JE-UK Laboratory of Molecular Cancer Therapeutics, Seoul, Republic of Korea.
Ji Min
JM
Lee
Yonsei Cancer Research Institute, JE-UK Laboratory of Molecular Cancer Therapeutics, Seoul, Republic of Korea.
Sang Gyun
SG
Kim
Yonsei Cancer Research Institute, JE-UK Laboratory of Molecular Cancer Therapeutics, Seoul, Republic of Korea.
Chae Won
CW
Park
Hematology and Medical Oncology, International St. Mary's Hospital, Catholic Kwandong University, College of Medicine, Incheon, Republic of Korea.
Hyun
H
Chang
Department of Pathology, Yonsei University College of Medicine, Seoul, Republic of Korea.
Hyo Sup
HS
Shim
Department of Biochemistry, College of Life Science and Biotechnology and Yonsei Laboratory Animal Research Center, Yonsei University, Seoul, Republic of Korea.
Han-Woong
HW
Lee
Division of Medical Oncology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea. Electronic address: cbc1971@yuhs.ac.
Byoung Chul
BC
Cho
D000818:Animals; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D015514:Oncogene Proteins, Fusion / Q000235:genetics* / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use*; D014407:Tumor Cells, Cultured
C522504:EML4-ALK fusion protein, human; D015514:Oncogene Proteins, Fusion; D047428:Protein Kinase Inhibitors
Cre-LoxP; EML4-ALK; Lung cancer; SPC promoter; Transgenic mouse