title: L-Asparaginase encapsulated intact erythrocytes for treatment of acute lymphoblastic leukemia (ALL).
abstract: As a primary drug for the treatment of acute lymphoblastic leukemia (ALL), encapsulation of L-asparaginase (ASNase) into red blood cells (RBC) has been popular to circumvent immunogenicity from the exogenous protein. Unlike existing methods that perturbs RBC membranes, we introduce a novel method of RBC-incorporation of proteins using the membrane-translocating low molecular weight protamine (LMWP). Confocal study of fluorescence-labeled LMWP-ovalbumin, as a model protein conjugate, has shown significant fluorescence inside RBCs. Surface morphology by scanning electron microscopy of the RBCs loaded with LMWP-ASNase was indistinguishable with normal RBCs. These drug loaded RBCs also closely resembled the profile of the native erythrocytes in terms of osmotic fragility, oxygen dissociation and hematological parameters. The in vivo half-life of enzyme activity after administering 8 units of RBC/LMWP-ASNase in DBA/2 mice was prolonged to 4.5+/-0.5 days whereas that of RBCs loaded with ASNase via a hypotonic method was 2.4+/-0.7 days. Furthermore, the mean survival time of DBA/2 mice bearing mouse lymphoma cell L5178Y was improved by approximately 44% compared to the saline control group after treatment with the RBC loaded enzymes. From these data, an innovative, novel method for encapsulating proteins into intact and fully functional erythrocytes was established for potential treatment of ALL.
authors: Tianjin Key Laboratory for Modern Drug Delivery and High Efficiency, Tianjin University, Tianjin 300072, China.
authors: Young Min
authors: YM
authors: Kwon
authors: Hee Sun
authors: HS
authors: Chung
authors: Cheol
authors: C
authors: Moon
authors: James
authors: J
authors: Yockman
authors: Yoon Jeong
authors: YJ
authors: Park
authors: Scott D
authors: SD
authors: Gitlin
authors: Allan E
authors: AE
authors: David
authors: Victor C
authors: VC
authors: Yang
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000097:blood / Q000493:pharmacokinetics / Q000494:pharmacology*; D001215:Asparaginase / Q000097:blood / Q000493:pharmacokinetics / Q000494:pharmacology*; D001692:Biological Transport; D045744:Cell Line, Tumor; D002626:Chemistry, Pharmaceutical; D004337:Drug Carriers; D004339:Drug Compounding; D004795:Enzyme Stability; D017707:Erythrocyte Transfusion; D004912:Erythrocytes / Q000201:enzymology* / Q000648:ultrastructure; D005240:Feasibility Studies; D006461:Hemolysis; D051379:Mice; D008811:Mice, Inbred DBA; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D008970:Molecular Weight; D009996:Osmotic Fragility; D010047:Ovalbumin / Q000097:blood; D010865:Pilot Projects; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy* / Q000473:pathology; D011479:Protamines / Q000097:blood* / Q000737:chemistry; D012756:Sheep
chemical_list: D000970:Antineoplastic Agents; D004337:Drug Carriers; D011479:Protamines; D010047:Ovalbumin; D001215:Asparaginase