NCI-H441 subcutaneous in vivo xenograft tumor model

The animal experimental protocol was approved by the Institutional Animal Care and Use Committee at the affiliated hospital of Chengdu University. All experiments were conducted in accordance with the guidelines for animal care and welfare of China. Briefly, NCI-H441 cells transfected with miR-183 mimics or mock vectors (8×10⁷ cells in 100 μL PBS) were mixed 1:1 with Matrigel and subcutaneously injected into the right flank of each 6–8-week-old balb/c nu/nu mouse (Vital River, Beijing, China). Then, 5 mg/kg melittin or vehicle was orally administered to the respective groups daily for 4 weeks. The tumor size was monitored weekly using calipers, and the body weight of the mice was also monitored once per week. Tumor volumes (TV) were calculated using the following formula: TV=(length × width²)/2. Both length and width were measured in mm. Mice were euthanized at the termination of the experiment and tumors from each group were excised for weighing on electronic scales. Then, a portion of each tumor was fast frozen in liquid nitrogen for further measurements, while the remaining tumor sections were lysed for protein analysis.