4.12. Xenograft Models

Male BALB/C-nu/nu nude mice weighing 19–21 g (3–4 weeks old, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China) were used in this study. To evaluate in vivo tumorigenesis, MGC-803 cells (2 × 10⁶/200 μL) transfected with shFOXO3a or shRNA were injected subcutaneously into mice armpits subcutaneous of left forelimb. After seven days, the tumors reached approximately 100 mm³. Then, the mice in two groups were randomly divided into two groups that were injected with As₂O₃ (5 mg/kg/day) or the same volume of saline solution into the abdominal cavity every day. This concentration was based on our laboratory’s previous exploration of the concentration of As₂O₃ in mice. Eight mice per group were used for each set of experiments. After 14 days, four groups of mice were sacrificed and the tumor masses were collected. Care of experimental animals was in accordance with institutional animal care and use committee guidelines. All animal experiments were approved by the Experimental Animal Ethics Committee of Xuzhou Medical University (SYXK2015-0030, 14 March 2017).