The biological properties evaluation of the radiolabeled complex: 99mTc -DTPA- Herceptin in cancerous cell lines

Aim and Herceptin as a humanized monoclonal antibody against HER2 is used for the treatment of the early stage of HER2 over-expresed breast cancers. This antibody has the potential to be used as radioimmuno-scintigraphy agent in diagnosing HER2 breast cancer. In this study, the radiolabeling of Herceptin with 99mTc was evaluated for the first step in producing a new radiopharmaceutical agent. Herceptin antibody was labeled with Technetium-99m using Diethylene Triamine Pentaacetic Acid (DTPA) as chelator. All the quality control tests were performed. Labeling efficiency, stability in buffer and serum, immunoreactivity, toxicity and cell binding of the complex were tested on different breast cancer cell lines. The labeling efficiency of the complex was 97 ± 2%. The stabilities in phosphate buffer and in human blood serum within 24 h post preparation were 96 ± 1% and 90 ± 2%, respectively. The immunoreactivity of the complex was 83 ± 3%. The binding of labeled antibody to the surface of SKBR3, MCF7 and A431 cells were increased by increasing Her2 concentration on the cells surface. No cytotoxicity effect of complex was seen on the cell lines. The findings showed that 99mTc-DTPA-Herceptin can be a promising candidate as HER2 antigen scanning for human breast cancer that needs more investigations in future.