SNX-5422 inhibits human MM cell growth and angiogenesis in vivo. (A) SNX-5422 significantly inhibits MM tumor growth compared with controls: control (♦), 20 mg/kg (▴), and 40 mg/kg (■) SNX-5422 (n = 7); control versus 20 mg/kg (P < .05); and control versus 40 mg/kg (P < .01). Error bars represent mean plus or minus SD. (B) In Kaplan-Meier curve and log-rank analysis, SNX-5422 markedly prolongs overall survival of treated groups compared with the control group (P < .01). (C) SNX-5422 significantly induces MM cell apoptosis in treated mice (40 mg/kg) compared with control mice, evidenced by TUNEL assay. (D) SNX-5422 significantly inhibits p-ERK in treated mice (40 mg/kg), evidenced by immunohistochemical analysis of p-ERK staining. (E) Effect of SNX-5422 on MVD in tumors. MVD was evaluated by immunohistochemical analysis for CD31 expression. Inhibition of blood vessel formation was observed in SNX-5422-treated mice compared with control mice (P < .01). Blood vessels (mean ± SD of 5 separate HPFs) were enumerated at ×40. Images in panels C-E were obtained using a Leica DMIL microscope equipped with a 4×, 10×/0.22, and 40×/0.60 numeric aperture objective lens and acquired through IM50 software. Original magnification ×40.