Tumor Microenvironment Modulation by Cyclopamine Improved Photothermal Therapy of Biomimetic Gold Nanorods for Pancreatic Ductal Adenocarcinomas

Due to the rich stroma content and poor blood perfusion, pancreatic ductal adenocarcinoma (PDA) is a tough cancer that can hardly be effectively treated by chemotherapeutic drugs. Tumor microenvironment modulation or advanced design of nanomedicine to achieve better therapeutic benefits for PDA treatment was widely advocated by many reviews. In the present study, a new photothermal therapy strategy of PDA was developed by combination of tumor microenvironment modulation and advanced design of biomimetic gold nanorods. On one hand, biomimetic gold nanorods were developed by coating gold nanorods (GNRs) with erythrocyte membrane (MGNRs). It was shown that MGNRs exhibited significantly higher colloidal stability in vitro, stronger photothermal therapeutic efficacy in vitro, and longer circulation in vivo than GNRs. On the other hand, tumor microenvironment modulation by cyclopamine treatment successfully disrupted the extracellular matrix of PDA and improved tumor blood perfusion. Moreover, cyclopamine treatment significantly increased the accumulation of MGNRs in tumors by 1.8-fold and therefore produced higher photothermal efficiency in vivo than the control group. Finally, cyclopamine treatment combined with photothermal MGNRs achieved the most significant shrinkage of Capan-2 tumor xenografts among all the treatment groups. Therefore, with the integrated advantages of tumor microenvironment regulation and long-circulation biomimetic MGNRs, effective photothermal therapy of PDA was achieved. In general, this new strategy of combining tumor microenvironment modulation and advanced design of biomimetic nanoparticles might have great potential in PDA therapy.