Supplementary Files contain (1) Supplementary Materials and Methods for ï�¡Vï�¢3 expression analysis, autoradiography and histological analysis, and hematology and hepatorenal function; (2) Supplementary Tables S1-S5; and (3) Supplementary Figures S1-S5. Table S1ï€Effects of 37 MBq (1 nmol) of 64Cu-cyclam-RAFT-c(-RGDfK-)4 {plus minus} GF/Lys on hepatorenal functions of U87MG tumor-bearing mice; Table S2ï€Blood cell counts of U87MG tumor-bearing mice at various time points post-injection of 37 MBq (1 nmol) of 64Cu-cyclam-RAFT-c(-RGDfK-)4 {plus minus} GF/Lys; Table S3ï€Blood cell counts of U87MG tumor-bearing mice at various time points after single dose administrations of 37 and 74 MBq of 64Cu-cyclam-RAFT-c(-RGDfK-)4; Table S4ï€Effects of 74 MBq (2 nmol) of 64Cu-cyclam-RAFT-c(-RGDfK-)4 + GF/Lys on hepatorenal functions of normal mice; Table S5ï€Human absorbed doses extrapolated from the biodistribution data of 64Cu-cyclam-RAFT-c(-RGDfK-)4 in U87MG tumor-bearing mice
ARTICLE ABSTRACT
The transmembrane cell adhesion receptor αVβ3 integrin (αVβ3) has been identified as an important molecular target for cancer imaging and therapy. We have developed a tetrameric cyclic RGD (Arg-Gly-Asp) peptide–based radiotracer 64Cu-cyclam-RAFT-c(-RGDfK-)4, which successfully captured αVβ3-positive tumors and angiogenesis by PET. Here, we subsequently evaluated its therapeutic potential and side effects using an established αVβ3-positive tumor mouse model. Mice with subcutaneous U87MG glioblastoma xenografts received single administrations of 37 and 74 MBq of 64Cu-cyclam-RAFT-c(-RGDfK-)4 (37 MBq/nmol), peptide control, or vehicle solution and underwent tumor growth evaluation. Side effects were assessed in tumor-bearing and tumor-free mice in terms of body weight, routine hematology, and hepatorenal functions. Biodistribution of 64Cu-cyclam-RAFT-c(-RGDfK-)4 with ascending peptide doses (0.25–10 nmol) and with the therapeutic dose of 2 nmol were determined at 3 hours and at various time points (2 minutes–24 hours) postinjection, respectively, based on which radiation-absorbed doses were estimated. The results revealed that 64Cu-cyclam-RAFT-c(-RGDfK-)4 dose dependently slowed down the tumor growth. The mean tumor doses were 1.28 and 1.81 Gy from 37 and 74 MBq of 64Cu-cyclam-RAFT-c(-RGDfK-)4, respectively. Peptide dose study showed that the tumor uptake of 64Cu-cyclam-RAFT-c(-RGDfK-)4 dose dependently decreased at doses ≥1 nmol, indicating a saturation of αVβ3 with the administered therapeutic doses (1 and 2 nmol). Combined analysis of the data from tumor-bearing and tumor-free mice revealed no significant toxicity caused by 37–74 MBq of 64Cu-cyclam-RAFT-c(-RGDfK-)4. Our study demonstrates the therapeutic efficacy and safety of 64Cu-cyclam-RAFT-c(-RGDfK-)4 for αVβ3-targeted radionuclide therapy. 64Cu-cyclam-RAFT-c(-RGDfK-)4 would be a promising theranostic drug for cancer imaging and therapy. Mol Cancer Ther; 15(9); 2076–85. ©2016 AACR.
