A gene therapy approach to regulated delivery of erythropoietin as a function of oxygen tension
Current therapy for several forms of anemia involves a weekly regime of multiple subcutaneous injections of recombinant human erythropoietin (hEpo). In an effort to provide a physiologically regulated administration of erythropoietin, we are developing cell lines genetically engineered to release hEpo as a function of oxygen tension. C2C12 cells were transfected using a vector containing the hEpo cDNA driven by the hypoxia-responsive promoter to the murine phosphoglycerate kinase gene. In vitro, these cells showed a threefold increase in hEpo secretion as oxygen levels were shifted from 21% to 1.3% oxygen. To test in vivo response, C2C12-hEpo cells were encapsulated in a microporous membrane and implanted subcutaneously on the dorsal flank of DBA/2J mice. On average, serum hEpo levels in animals exposed to 7% oxygen were two-fold higher than values seen in their control counterparts kept at 21% oxygen. Similar studies employing rats confirmed that hEpo delivery is regulated as a function of oxygen tension. These results suggest the feasibility of developing an oxygen-regulated, encapsulated cell-based system for hEpo delivery.
Keywords: Anemia/therapy ; Animals ; Anoxia/metabolism ; Cells ; Cultured ; DNA-Binding Proteins/genetics ; Drug Compounding ; Erythropoietin ; Recombinant/blood/ genetics/metabolism ; Gene Expression Regulation ; Gene Therapy/ methods ; Histocytochemistry ; Hypoxia-Inducible Factor 1 ; Hypoxia-Inducible Factor 1 ; alpha Subunit ; Mice ; Mice ; Inbred DBA ; Nuclear Proteins/genetics ; Oxygen/blood/ physiology ; Partial Pressure ; Phosphoglycerate Kinase/genetics ; Plasmids/genetics ; Promoter Regions (Genetics)/genetics ; Rats ; Rats ; Inbred F344 ; Transcription Factors ; Transgenes
Gene Therapy Center, Centre Hospitalier Universitaire Vaudois, Lausanne University Medical School, Switzerland.
Record created on 2007-03-09, modified on 2016-08-08