Targeted Photodynamic Pre-Treatment: a Novel to Strategy to Enhance Tumor Accumulation of Nanomedicines

Overchuk, Marta1, 3; Harmatys, Kara2; Sindwani, Shrey1; Abdullah, Syed1; Chen, Juan3; Pomper, Martin4; Chan, Warren1; Zheng, Gang1, 2, 3

1. Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada; 2. Department of Medical Biophysics, University of Toronto; 3. Princess Margaret Cancer Centre and Techna Institute, University Health Network, Toronto, ON, Canada; 4. Johns Hopkins School of Medicine, Baltimore, Maryland, USA

Drug encapsulation into a nanoparticle enables improved  pharmacokinetics, decreased toxicity and co-delivery of multiple drugs with contrast agents. Despite being widely explored, this approach has not been proven more efficacious in cancer eradication compared to free chemotherapy drugs, primarily due to low nanoparticle tumor uptake and poor tissue penetration. Multiple strategies, such as vasodilation, radiation and hyperthermia have been proposed to enhance tumor accumulation of nanomedicines and to improve their intratumoral distribution. Photodynamic therapy (PDT) is an emerging therapeutic modality that employs a non-toxic light-sensitive drug (photosensitizer) in combination with light to produce reactive oxygen species and destroy nearby cancer cells. Several recent studies suggest that photodynamic pre-treatment using antibody-photosensitizer conjugates may lead to higher tumor uptake of nanomedicines and delayed tumor growth.