Genome-wide analysis of alpharetroviral integration in human hematopoietic stem/progenitor cells.
Gene transfer vectors derived from gamma-retroviruses or lentiviruses are currently used for the gene therapy of genetic or acquired diseases. Retroviral vectors display a non-random integration pattern in the human genome, targeting either regulatory regions (gamma-retroviruses) or the transcribed portion of expressed genes (lentiviruses), and have the potential to deregulate gene expression at the transcriptional or post-transcriptional level. A recently developed alternative vector system derives from the avian sarcoma-leukosis alpha-retrovirus (ASLV) and shows favorable safety features compared to both gamma-retroviral and lentiviral vectors in preclinical models. We performed a high-throughput analysis of the integration pattern of self-inactivating (SIN) alpha-retroviral vectors in human CD34+ hematopoietic stem/progenitor cells (HSPCs) and compared it to previously reported gamma-retroviral and lentiviral vectors integration profiles obtained in the same experimental setting. Compared to gamma-retroviral and lentiviral vectors, the SIN-ASLV vector maintains a preference for open chromatin regions, but shows no bias for transcriptional regulatory elements or transcription units, as defined by genomic annotations and epigenetic markers (H3K4me1 and H3K4me3 histone modifications). Importantly, SIN-ASLV integrations do not cluster in hot spots and target potentially dangerous genomic loci, such as the EVI2A/B, RUNX1 and LMO2 proto-oncogenes at a virtually random frequency. These characteristics predict a safer profile for ASLV-derived vectors for clinical applications.
Genethon, 1bis Rue de l'Internationale, 91020 Evry, France. amoiani@genethon.fr.
Arianna
A
Moiani
Institute of Experimental Hematology, Hannover Medical School, Carl-Neuberg-Str.1, D-30625 Hannover, Germany. suerth.julia@mh-hannover.de.
Julia Debora
JD
Suerth
Genethon, 1bis Rue de l'Internationale, 91020 Evry, France. fgandolfi@genethon.fr.
Francesco
F
Gandolfi
Institute for Biomedical Technologies, Consiglio Nazionale delle Ricerche, Milan 20132, Italy. ermanno.rizzi@itb.cnr.it.
Ermanno
E
Rizzi
Institute for Biomedical Technologies, Consiglio Nazionale delle Ricerche, Milan 20132, Italy. marco.severgnini@itb.cnr.it.
Marco
M
Severgnini
Institute for Biomedical Technologies, Consiglio Nazionale delle Ricerche, Milan 20132, Italy. gianluca.debellis@itb.cnr.it.
Gianluca
G
De Bellis
Institute of Experimental Hematology, Hannover Medical School, Carl-Neuberg-Str.1, D-30625 Hannover, Germany. schambach.axel@mh-hannover.de.
Axel
A
Schambach
Genethon, 1bis Rue de l'Internationale, 91020 Evry, France. fmavilio@genethon.fr.
Fulvio
F
Mavilio