Cancer-specific nanotheranostics to improve the diagnosis and treatment of bladder cancer.

Abstract

323 Background: We recently developed a bladder cancer-specific targeting ligand named PLZ4, nanometer-scale micelles and nanoporphyrin. Here we report the diagnostic and therapeutic applications of these nanotheranostics coated with PLZ4. Methods: PLZ4 was synthesized through solid phase synthesis. Bladder cancer-specific PLZ4-coated nanomicelles (PNM) and nanoporphyrin (PNP) were developed through conjugating the nanotheranostics with PLZ4 on the surface, and loaded with therapeutic and/or imaging agents in the core. Bladder cancer cell lines and patient-derived xenografts (PDXs) were used to determine the diagnostic and therapeutic applications. Results: In vitro studies with cell lines revealed that both PNM and PNP could specifically deliver the drug load to bladder cancer cells, but not to adjacent confounding cells. After intravenous injection, PNM loaded with paclitaxel could specifically deliver the drug load to xenografts developed from a human and a dog bladder cancer cell line, and a PDX, but not to lung cancer xenografts in the same mice. These paclitaxel-loaded PNM could overcome cisplatin resistance, and prolong the overall survival of mice carrying PDXs from 27 days with free paclitaxel to 76 days (p<0.0001). PNP can be used for photodynamic diagnosis and therapy while being able to chelate gadolinium for cancer-specific magnetic resonance imaging (MRI), and load chemotherapeutic drugs for cancer-specific targeted chemotherapy. It is over 50 times more potent that 5-aminolevulinic acid in photodynamic therapy (p<0.0001). After intravesical instillation into the bladder cavity of an orthotopic PDX model, PNP could specifically target bladder cancer cells, but not adjacent normal urothelial cells in the same bladder. Conclusions: PNM and PNP can potentially be used for diagnosis, imaging detection and cancer-specific targeted delivery of therapeutic agents of both non-myoinvasive and advanced bladder cancer. A phase I clinical trial of PNM for intravesical instillation in human patients with non-myoinvasive bladder cancer, and another phase I trial with PNP for photodynamic diagnosis and therapy in dog bladder cancer patients have been funded.