ABSTRACT
The in vitro efficacy of cancer prodrugs varies significantly between malignant cell lines. The most commonly identified problems relate to delivery: uptake mechanism, endosomal entrapment, and drug release. Here we present the study of collagen/cell penetrating hybrid (COL/CPP) peptide carriers intended to deliver paclitaxel to the hypopharyngeal carcinoma (FaDu) cells. Confocal microscopy imaging revealed the surprising response of FaDu cell to COL/CPP in comparison to previously studied cancer cell lines: hybrid peptides that carry both COL and CPP domain adsorb on the FaDu cell surface. While the CPP domain was design to facilitate the cellular uptake, in the case of FaDu cells, it also induced detrimental interactions with the cell membrane. Despite surface adsorption, the colocalization study with endosomal markers EEA1 and LAMP1 reveals that COL/CPP is internalized via endosomal pathway, peptides are able to escape before lysosome formation and release paclitaxel. Therefore, the main obstacle for paclitaxel delivery to FaDu cells appears to be related to cell surface properties. This behavior seems specific to FaDu cells, and could be linked to previously reported overexpression of T5, heparanase splice variants that produces protein lacking enzymatic activity of heparanase. This results in increased concentration of HSPG on FaDu cell surface, and possibly creates a barrier for cellular uptake of highly charged COL/CPP.
Subject(s)
Cell-Penetrating Peptides/pharmacology , Drug Carriers/pharmacology , Heparan Sulfate Proteoglycans/chemistry , Hypopharyngeal Neoplasms/drug therapy , Cell Line, Tumor , Cell-Penetrating Peptides/chemistry , Collagen/chemistry , Collagen/pharmacology , Drug Carriers/chemistry , Drug Liberation/genetics , Endosomes/chemistry , Endosomes/drug effects , Gene Expression Regulation, Neoplastic/drug effects , Humans , Hypopharyngeal Neoplasms/genetics , Hypopharyngeal Neoplasms/pathology , Lysosomal Membrane Proteins/genetics , Paclitaxel/chemistry , Paclitaxel/pharmacology , Surface Properties , Vesicular Transport Proteins/geneticsABSTRACT
Paclitaxel (PTX) is one of the most potent cancer drugs; however, its low solubility and strong systemic side effects limit its clinical applications. To overcome these issues, new drug formulations and chemical modifications have been proposed. In this study, we present conjugation of PTX to hybrid collagen-cell penetrating peptide (COL-CPP) carriers. The peptide carrier is highly soluble and utilizes a unique stabilization strategy: folding into a triple helix. Here, we report the formation of PTX-COL-CPP prodrug that has similar drug potency as free PTX when tested in Jurkat (human T lymphocyte of acute T cell leukemia) cells but not in A549 (human epithelial of lung carcinoma) cells. Confocal images and flow cytometry show that this behavior originates from lower cellular uptake of COL-CPP and endosomal entrapment of the prodrug in A549, but not in Jurkat cells.
