PTD-Mediated Red Blood Cell Encapsulation of L-Asparaginase for PotentialTreatment of Acute Lymphoblastic Leukemia.

[摘要] One of the primary drugs used in treatment of acute lymphoblastic leukemia is L-asparaginase (ASNase), which despite its therapeutic efficacy, faces challenges often faced in protein drug treatment: the immunogenicity and short half-life of the drug. In order to overcome these major challenges, the red blood cell (RBC)encapsulation method has been employed to prevent degradation by serum proteases and elimination by reticuloendothelial system, thereby increasing circulation half-life of the protein drug. However, the encapsulation methods used thus far, such as hypotonic dialysis/resealing and electroporation, showed compromise in the oxygen transport function and structural integrity of RBCs. Herein we introduce a novel RBC encapsulation method that involves low molecular weight protamine (LMWP), a protein transduction domain (PTD) peptide. Protein drug was first conjugated to LMWP via disulfide bond and the cell penetrating property of LMWP allowed encapsulation of protein drug into RBCs as verified by the confocal microscopy images. The optimal encapsulation condition was determined to be 37 °C for 30 minutes. Hematological parameters as well as SEM and osmotic fragility curve of LMWP-ASNase encapsulated RBCs showed that the structural integrity was maintained while Hill coefficients and pO50 values indicated oxygen transport functionality was maintained. LMWP-mediated encapsulation method considerably increased the circulating half-life of ASNase compared to that of the hypo-osmotic rupture/resealing method and improved the survival time of tumor-bearing mice by 44% compared to the saline control group. Based on these data, novel method for encapsulating protein drugs into intact and fully functional RBCs was established for potential treatment of acute lymphoblastic leukemia.

[发布机构] University of Michigan

[效力级别] Carrier Erythrocytes

[关键词] Red Blood Cell (RBC) Carriers;Carrier Erythrocytes;Cell Penetrating Peptide (CPP);Protein Transduction Domain (PTD) Peptide;Low Molecular Weight Protamine;Pharmacy and Pharmacology;Science (General);Health Sciences;Science;Pharmaceutical Sciences