Enhancement of anticancer efficacy using modified lipophilic nanoparticle drug encapsulation

Puiyan Lee¹, Ruizhong Zhang¹, Vincent Li¹, Xuelai Liu¹, Raymond WY Sun², Chi-Ming Che², Kenneth KY Wong^1
1Department of Surgery, Li Ka Shing Faculty of Medicine, ²Department of Chemistry and Open Laboratory of Chemical Biology of the Institute of Molecular Technology for Drug Discovery and Synthesis, The University of Hong Kong, Hong Kong

Background: Development of anticancer drugs is challenging. Indeed, much research effort has been spent in the development of new drugs to improve clinical outcomes with minimal toxicity. We have previously reported that a formulation of lipid gold porphyrin nanoparticles reduced systemic drug toxicity when compared with free gold porphyrin. In this study, we investigated the delivery and treatment efficiency of PEG surface-modified lipid nanoparticles as a carrier platform.
Methods: We encapsulated antitumor drugs into PEG-modified lipid nanoparticles and these were characterized by size, zeta potential, and encapsulation efficiency. The delivery efficiency into tumor tissue was evaluated using a biodistribution study. To evaluate antitumor efficacy, gold porphyrin or camptothecin (a DNA topoisomerase I inhibitor) were encapsulated and compared using an in vivo neuroblastoma (N2A) model.
Results: We showed that drug encapsulation into PEG-modified lipid nanoparticles enhanced the preferential uptake in tumor tissue. Furthermore, higher tumor killing efficiency was observed in response to treatment with PEG-modified lipid nanoparticles encapsulating gold porphyrin or camptothecin when compared with free gold porphyrin or free camptothecin. The in vivo antitumor effect was further confirmed by study of tumor inhibition and positive apoptosis activity. Surface modification of lipophilic nanoparticles with PEG increased the efficiency of drug delivery into tumor tissue and subsequently more effective antitumor activity.
Conclusion: This specific design of a chemotherapeutic agent using nanotechnology is important in the development of a safe and effective drug in cancer therapy.

Keywords: lipid nanoparticles, gold porphyrin, cancer, neuroblastoma, camptothecin