Tissue specific cytotoxicity of colon cancer cells mediated by nanoparticle-delivered suicide gene in vitro and in vivo.

PURPOSE This study aimed to develop an efficient and safe strategy to introduce suicide genes into colon cancer cells. EXPERIMENTAL DESIGN In this study, we fused an enhanced carcinoembryonic antigen promoter (CEA) to a suicide gene, cytosine deaminase (CD). This construct was delivered into colon cancer cells using calcium phosphate nanoparticles (CPNP). The cells were then treated with the prodrug 5-FC. The therapeutic effect was evaluated in vitro and in vivo. RESULTS Our study showed that the CEA promoter-driven, CPNP-delivered suicide gene was only expressed in CEA-positive colon cancer cells, and resulted in significant cytotoxicity after administration of the prodrug 5-FC in vitro. Moreover, our in vivo study showed that CPNP-mediated CEA-CD delivery, together with 5-FC treatment, resulted in significant tumor growth delay in xenograft human colon carcinoma. CONCLUSIONS Our study indicates that the combination of CPNP and CEA-CD gene expression represents a novel approach for CEA-positive tumor gene therapy.