Siler
Fakultäten » Medizinische Fakultät » Kinderspital Zürich: Medizinische Klinik » Immunologie, Abteilung » Prof. Dr. Reinhard Seger (emeritiert) » Siler
Completed research project
| Title / Titel | Retroviral delivery of episomal vectors to hematopoietic stem cells; a feasibility study | ||
|---|---|---|---|
| Abstract (PDF, 14 KB) | |||
| Summary / Zusammenfassung | In 2005 we conducted together with our collaboration partners in Germany the first successful clinical gene therapy (GT) trial aimed at the correction of the X-linked form of Chronic Granulomatous Disease (CGD). In addition to proof-of-principle, the trial revealed transactivation of proto-oncogenes by integrating retroviral vectors as serious risk factor in GT. An alternative new approach of transgene expression is the use of episomal vectors being maintained as extrachromosomal DNA in the nucleus of dividing cells. The application of this approach to GT within the hematopoietic system is limited by the lack of a suitable method for large scale plasmid delivery to CD34+ cells. Present project intends bypassing the risk factor “transactivation” in current gammaretroviral gene therapy approach by combining the gammaretroviral with the episomal approach: Gammaretroviral infection incompetent particles will be used to deliver RNA transcribed to initially linear, proviral doublestranded DNA to CD34+ stem cells. This non-integrating linear DNA is known to undergo a side-reaction of normal retroviral integration, the circularization. Hence integration-incompetent gammaretroviral particles can be used to deliver a circular, episomal construct in large scale to human CD34+ stem cells, the lacking tool in application of episomal vectors to GT. After delivery of the episomal construct into the nucleus the episomal constructs replicate and are maintained in the nucleus as extrachromosomal DNA. There are no indications for a interaction between episomal vectors and chromosomal genes which could lead to transactivation of chromosomal genes. Therefore the transgene expression from an episomal vector would represent an important safety improvement compared to current integrating vectors. |
||
| Publications / Publikationen | Ott MG, Schmidt M, Schwarzwaelder K, Stein S, Siler U, Koehl U, Glimm H, Kuhlcke K, Schilz A, Kunkel H, Naundorf S, Brinkmann A, Deichmann A, Fischer M, Ball C, Pilz I, Dunbar C, Du Y, Jenkins NA, Copeland NG, Luthi U, Hassan M, Thrasher AJ, Hoelzer D, von Kalle C, Seger R, Grez M. Correction of X-linked chronic granulomatous disease by gene therapy, augmented by insertional activation of MDS1-EVI1, PRDM16 or SETBP1. Nat Med. (2006) 12: 401-9Stein S, Siler U, Ott MG, Seger R, Grez M. Gene therapy for chronic granulomatous disease. Curr Opin Mol Ther. (2006) 8: 415-22 | ||
| Keywords / Suchbegriffe | episomal vector, gammaretrovirus, gene therapy | ||
| Project leadership and contacts / Projektleitung und Kontakte |
|
||
| Funding source(s) / Unterstützt durch |
Others Bonizzi-Theler-Stiftung |
||
| In collaboration with / In Zusammenarbeit mit |
|
||
| Duration of Project / Projektdauer | Nov 2007 to Nov 2009 |