Lung tumorigenesis induced by human vascular endothelial growth factor (hVEGF)-A165 overexpression in transgenic mice and amelioration of tumor formation by miR-16

// Yu-Tang Tung 1, * , Pin-Wu Huang 1, * , Yu-Ching Chou 1 , Cheng-Wei Lai 1 , Hsiu-Po Wang 1 , Heng-Chien Ho 2 , Chih-Ching Yen 1, 3 , Chih-Yen Tu 1, 3 , Tung-Chou Tsai 1 , Dah-Cherng Yeh 4 , Jiun-Long Wang 1, 5 , Kowit-Yu Chong 6, 7 , Chuan-Mu Chen 1, 8 1 Department of Life Sciences, and Agricultural Biotechnology Center, National Chung Hsing University, Taichung 402, Taiwan 2 Department of Medicine, China Medical University Hospital, Taichung 404, Taiwan 3 Department of Internal Medicine, China Medical University Hospital, Taichung 404, Taiwan 4 Department of General Surgery and Department of Internal Medicine, Taichung Veterans General Hospital, Taichung 407, Taiwan 5 Division of Chest Medicine, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung 407, Taiwan 6 Department of Medical Biotechnology and Laboratory Sciences, College of Medicine, Chang Gung University, Tao-Yuan 333, Taiwan 7 Molecular Medicine Research Center, College of Medicine, Chang Gung University, Tao-Yuan 333, Taiwan 8 Rong-Hsing Translational Medicine Center and iEGG Center, National Chung Hsing University, Taichung 402, Taiwan * These authors have contributed equally to this work Correspondence to: Chuan-Mu Chen, e-mail: chchen1@dragon.nchu.edu.tw Keywords: VEGF, transgenic mice, pulmonary tumorigenesis, magnetic resonance imaging (MRI), miRNA therapy Received: November 03, 2014      Accepted: April 10, 2015      Published: April 22, 2015 ABSTRACT Many studies have shown that vascular endothelial growth factor (VEGF), especially the human VEGF-A 165 (hVEGF-A 165 ) isoform, is a key proangiogenic factor that is overexpressed in lung cancer. We generated transgenic mice that overexpresses hVEGF-A 165 in lung-specific Clara cells to investigate the development of pulmonary adenocarcinoma. In this study, three transgenic mouse strains were produced by pronuclear microinjection, and Southern blot analysis indicated similar patterns of the foreign gene within the genomes of the transgenic founder mice and their offspring. Accordingly, hVegf-A 165 mRNA was expressed specifically in the lung tissue of the transgenic mice. Histopathological examination of the lung tissues of the transgenic mice showed that hVEGF-A 165 overexpression induced bronchial inflammation, fibrosis, cysts, and adenoma. Pathological section and magnetic resonance imaging (MRI) analyses demonstrated a positive correlation between the development of pulmonary cancer and hVEGF expression levels, which were determined by immunohistochemistry, qRT-PCR, and western blot analyses. Gene expression profiling by cDNA microarray revealed a set of up-regulated genes ( hvegf-A 165 , cyclin b1 , cdc2 , egfr , mmp9 , nrp-1 , and kdr ) in VEGF tumors compared with wild-type lung tissues. In addition, overexpressing hVEGF-A 165 in Clara cells increases CD105, fibrogenic genes ( collagen α1 , α-SMA , TGF-β1 , and TIMP1 ), and inflammatory cytokines (IL-1, IL-6, and TNF- α ) in the lungs of hVEGF-A 165 -overexpressing transgenic mice as compared to wild-type mice. We further demonstrated that the intranasal administration of microRNA-16 (miR-16) inhibited lung tumor growth by suppressing VEGF expression via the intrinsic and extrinsic apoptotic pathways. In conclusion, hVEGF-A 165 transgenic mice exhibited complex alterations in gene expression and tumorigenesis and may be a relevant model for studying VEGF-targeted therapies in lung adenocarcinoma.