Abstract 369: Improving the nanomaterial delivery by using cell-penetrating peptides in the bystander manner

Abstract

While nanoparticles (NPs) can be useful to improve the diagnosis and treatment of various diseases including cancer, a major limiting factor for their applications is the poor efficiency of cell entry. A common solution to this problem is to covalently link NPs with cell-penetrating peptides (CPPs), such as the transactivator of transcription (TAT) peptide. A few cationic CPPs were previously shown to increase the cellular uptake of co-administered, but not covalently coupled, NP cargo through an endocytic pathway, macropinocytosis. This so-called bystander uptake process is of unique advantage for NP intracellular delivery as it bypasses the requirements of additional chemical modifications. Here, we set out to determine whether other classes of CPPs (e.g. hydrophobic and amphiphilic) exhibit similar bystander activities, and what physico-chemical properties of NPs affect the bystander uptake process. First, we discovered that transportan (TP) peptide, an amphiphilic CPP, can initiate similar bystander uptake process for a variety of NPs and solute tracers. TP-induced bystander uptake relies on macropinocytosis as well, and occurs in a variety of cell types and in physiological tissues. Second, using TAT-functionalized NPs to stimulate the bystander effect, we showed that the bystander activity depends on the size of bystander NPs, with an optimal range around 50 nm in diameter. Compared to rod-like and triangular NPs, spherical NPs showed higher uptake in the bystander manner. Additionally, we investigated how CPP-NPs, once inside cells, get out of one cell and enter another, and found again that NP sizes affect the efficiency of CPP-NP intercellular transport as well. Overall, these efforts lay the foundation to further understand the bystander activity of CPP-assisted cell entry and improve the efficacy of nanomedicine in cancer and other human diseases. Citation Format: Yue-Xuan Li, Yushuang Wei, Hong-Bo Pang. Improving the nanomaterial delivery by using cell-penetrating peptides in the bystander manner [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 369.