Fig. 3

RC48 remarkably exerted antitumor activity in the A2058 CDX model. BALB/c nude mice were injected subcutaneously with 2 × 10⁶ A2058 cells. Mice with xenografts measuring approximately 100–150 mm³ were randomly allocated into four groups, including vehicle (VEH), RC48 (5 MPK and 10 MPK) and 10 mg/kg trastuzumab (10 MPK TRA). Tumor sizes and body weight were measured twice a week. A Tumor growth in the different treatment groups was evaluated in A2058 CDX model by caliper measurements. B–D Tumor growth inhibition (%), representative transplanted tumor weights and images were assessed at the end of the experiment. E The TUNEL assay showed a higher rate of cell apoptosis in the RC48 group compared with the vehicle and trastuzumab groups. TUNEL images were captured at 400× magnification, with a scale bar of 20 µm. F The protein levels of Mcl-1, CDK4, and p-Rb in xenograft tumor tissue were examined using immunoblot analysis. GAPDH was used as a loading control. G Pathological changes in these organs of A2058 mouse CDX model were evaluated using H&E staining assays. Images were captured at 400× magnification. Scale bars, 20 µm. Data represents the mean ± SEM of at least three independent experiments, and statistical significance was assessed using an unpaired t-test, *p < 0.05; **p < 0.01; ***p < 0.001 compared with control groups