Construction, Expression and Functional Characterization of the β-Lactamase with αv Integrin Ligands

Antibody-directed enzyme prodrug therapy (ADEPT) delivers chemotherapeutic agents at high concentration to tumor tissues while minimizing systemic drug exposure. β-Lactamases are particularly useful enzymes for ADEPT systems due to their unique substrate specificity, which allows the activation of a variety of lactam-based prodrugs with minimal interference from mammalian enzymes. This study used integrin αv β3 as a target for tumor-specific delivery of β- Lactamase. β-Lactamase was fused with ACDCRGDCFCG peptide (RGD4C) by recombinant DNA technology. Likewise, this study cloned a fused cDNA and successfully expressed active recombinant protein in E. coli purified with Ni- NTA resin. After purification, the protein showed the expected size of 42 kDa on Tricine-SDS-PAGE, and was further confirmed by Western blotting. Based on flow cytometric analysis, the purified protein was found to be active for specificity in breast cancer cell line, MCF-7, which supports the utility of the protein as an agent for ADEPT.