X-linked severe combined immunodeficiency (SCID-Xl) is uniformly fatal in the first years of life if left untreated. Hematopoietic stem cell (HSC) gene therapy offers the best therapeutic option for many patients who do not have HLA-matched donors. In SCID-Xl clinical studies gammaretroviral vector proviruses have dysregulated nearby proto-oncogenes including LM02, leading to clonal expansion and in some cases frank leukemia. Thus, safer vector systems that are less likely to transactivate proto-oncogenes are needed for SC1D-X1 gene therapy. FV vectors may be a safer alternative to the gammaretroviral vectors used for SCID- Xl clinical trials. They have a favorable integration profile with respect to integration near proto-oncogenes and a reduced propensity to transactivate nearby genes relative to gammaretroviral and lentiviral vectors. Our long term goal is to develop safer and more effective FV vectors for HSC gene therapy, and to better understand the relative risks of using these vectors. Additionally, we would like to better understand host restriction mechanisms that impact FVs. If host restriction mechanisms can be identified and eliminated from the cells used to produce FV vectors, FV vector titers may be improved. This would reduce the costs of future clinical trials, potentially leading to increased use of FV vectors in the clinic. Our objectives in this application are to establish the relative safety of FV vectors using a novel approach to assess genotoxicity, to develop safer insulated FV vectors, and to improve the efficiency of FV vector production. We will employ an innovative shuttle vector approach that does not rely on PCR-based exponential amplification to better understand potential FV vector genotoxicity. Our proposal is highly integrated with the other program Projects. We will collaborate to test our novel insulated FV SCID-Xl vectors in the mouse (Project 1) and dog (Project 2) SCID-Xl models using this novel shuttle vector approach to generate highly significant pre- clinical data. Our central hypothesis is that FV vector safety and efficiency of production can be improved. The proposed research is significant because it is expected to lead to the use of FV vectors in the clinic for life-threatening diseases including SCID-Xl.

Public Health Relevance

The proposed project is directly related to public health because developing improved methods to assess vector genotoxicity, and developing safer and more effective gene therapy vectors is expected to lead to successful treatment of SCID-Xl and other hematopoietic diseases. The proposed research is thus directly related to the NIH's mission to develop innovative research strategies and apply them to improve human health.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Program Projects (P01)
Project #
5P01AI097100-02
Application #
8567345
Study Section
Special Emphasis Panel (ZAI1-JTS-I)
Project Start
Project End
Budget Start
2013-08-01
Budget End
2014-07-31
Support Year
2
Fiscal Year
2013
Total Cost
$310,898
Indirect Cost
$51,284
Name
Seattle Children's Hospital
Department
Type
DUNS #
048682157
City
Seattle
State
WA
Country
United States
Zip Code
98105
Humbert, Olivier; Chan, Frieda; Rajawat, Yogendra S et al. (2018) Rapid immune reconstitution of SCID-X1 canines after G-CSF/AMD3100 mobilization and in vivo gene therapy. Blood Adv 2:987-999
Browning, D L; Everson, E M; Leap, D J et al. (2017) Evidence for the in vivo safety of insulated foamy viral vectors. Gene Ther 24:187-198
Singh, Swati; Khan, Iram; Khim, Socheath et al. (2017) Safe and Effective Gene Therapy for Murine Wiskott-Aldrich Syndrome Using an Insulated Lentiviral Vector. Mol Ther Methods Clin Dev 4:1-16
Nalla, Arun K; Trobridge, Grant D (2016) Prospects for Foamy Viral Vector Anti-HIV Gene Therapy. Biomedicines 4:
Browning, Diana L; Trobridge, Grant D (2016) Insulators to Improve the Safety of Retroviral Vectors for HIV Gene Therapy. Biomedicines 4:
Browning, Diana L; Collins, Casey P; Hocum, Jonah D et al. (2016) Insulated Foamy Viral Vectors. Hum Gene Ther 27:255-66
Bii, Victor M; Trobridge, Grant D (2016) Identifying Cancer Driver Genes Using Replication-Incompetent Retroviral Vectors. Cancers (Basel) 8:
Adair, Jennifer E; Waters, Timothy; Haworth, Kevin G et al. (2016) Semi-automated closed system manufacturing of lentivirus gene-modified haematopoietic stem cells for gene therapy. Nat Commun 7:13173
Nalla, Arun K; Williams, Theodore F; Collins, Casey P et al. (2016) Lentiviral vector-mediated insertional mutagenesis screen identifies genes that influence androgen independent prostate cancer progression and predict clinical outcome. Mol Carcinog 55:1761-1771
Humbert, Olivier; Gisch, Don W; Wohlfahrt, Martin E et al. (2016) Development of Third-generation Cocal Envelope Producer Cell Lines for Robust Lentiviral Gene Transfer into Hematopoietic Stem Cells and T-cells. Mol Ther 24:1237-46

Showing the most recent 10 out of 40 publications