Breast Tumor Targeting in Mice Bearing 4T1 Tumor with Labeled CXCR4 Antagonist Analogue

Chemokine receptor belongs to G-protein-coupled cell-surface receptors. CXCR4 as a chemokine receptor is over-expressed in many type of solid tumors and metastasis in which breast tumor is one of them. A CXCR4 targeted peptide was prepared and labeled with 99m Tc. Subsequently, receptor binding internalization, in vivo tumor uptake and biodistribution were assessed. The receptor binding internalization rate was evaluated using 4T1 breast tumor cells. BALB/c female mice bearing 4T1 tumors were employed for investigation of radioconjugate biodistribution. Radioconjugate was obtained with labeling yield of > 95%. The highest achieved specific activity was 123 MBq/nmol. The in vitro cell uptake test resulted specific internalization into 4T1 cells (average of 1.90 ± 0.12% of total add at 2 h). Animal biodistribution data showed tumor uptake of 1.18 ± 0.11% ID/g after 30 min post injection. Our findings demonstrated that the labeled peptide can be a suitable candidate for breast tumors imaging.