Figure 3.

Melittin suppresses tumor growth in a subcutaneous heterograft tumor model using BALB/c nude mice. Mice were inoculated with 1 × 10⁷ HCT116 cells; when tumor volumes reached 80 mm³, intratumoral melittin injections were administered at 1 mg/kg or 2 mg/kg every two days. (A) Tumors were collected from nude mice (n = 8) after a total of five treatments; (B) body weight changes were monitored over 10 days, with noticeable weight loss observed as the tumors progressed; (C) tumor volume changes were measured and statistically analyzed over 10 days; (D) the tumor inhibition ratio was calculated based on final tumor weight measurements; (E) H&E stained sections were utilized to assess the histopathological features of the tumor tissues. The area indicated by the arrow shows inflammatory cell infiltration, primarily consisting of lymphocytes and plasma cells; (F) immunohistochemical (IHC) analysis for Ki-67 indicated a significant reduction in tumor proliferation in melittin-treated mice; (G) TUNEL fluorescence intensity was markedly increased in the tumors of melittin-treated mice compared to the control group, further confirmed by statistical analysis, demonstrating melittin’s pro-apoptotic effects in tumor cells (n = 4). Statistical significance: *, p < 0.05, **, p < 0.01, ***, p < 0.001.