Treatment with PTD-A2 inhibits tumor growth and tumor angiogenesis. (A–E) Treatment with FITC–NGR-A2 inhibits tumor growth, neovessel formation, and tumor cell death in B16F10 tumors. (A) Photograph of B16F10 melanoma tumors resected after 13 d. Bar, 5 mm. (B) Comparison of tumor volume (n = 7 mice per group; 4 mg/kg NGR-Con or NGR-A2 was administered every other day). (C–E) Images (C) and quantification (D) of CD31-positive blood vessels (red) and TUNEL-positive cells (pink) over CD31-positive blood vessels (E) in B16F10 melanoma tumors. FITC, green; DAPI, blue. Bars, 50 µm. (F–I) Amigo2 shRNA–transfected B16F10 tumors with NGR-A2 display dramatically inhibited tumor growth and tumor vessel formation. (F) Image of Amigo2 shRNA–transfected B16F10 melanoma tumors resected after 14 d. Bar, 5 mm. (G) Comparison of tumor volumes (n = 7–8 mice per group; 4 mg/kg NGR-Con or NGR-A2 was administered every other day). (H and I) Images (H) and quantification (I) of CD31-positive blood vessels (red). (B and G) Data were analyzed using repeated measures of two-way analysis of variance. *, P < 0.05; **, P < 0.005; ***, P < 0.0001. ns, not significant. Data are means ± SD.