TY - JOUR
T1 - Uncovering and dissecting the genotoxicity of self-inactivating lentiviral vectors in vivo
AU - Cesana, Daniela
AU - Ranzani, Marco
AU - Volpin, Monica
AU - Bartholomae, Cynthia
AU - Duros, Caroline
AU - Artus, Alexandre
AU - Merella, Stefania
AU - Benedicenti, Fabrizio
AU - Sergi Sergi, Lucia
AU - Sanvito, Francesca
AU - Brombin, Chiara
AU - Nonis, Alessandro
AU - Serio, Clelia Di
AU - Doglioni, Claudio
AU - Von Kalle, Christof
AU - Schmidt, Manfred
AU - Cohen-Haguenauer, Odile
AU - Naldini, Luigi
AU - Montini, Eugenio
PY - 2014
Y1 - 2014
N2 - Self-inactivating (SIN) lentiviral vectors (LV) have an excellent therapeutic potential as demonstrated in preclinical studies and clinical trials. However, weaker mechanisms of insertional mutagenesis could still pose a significant risk in clinical applications. Taking advantage of novel in vivo genotoxicity assays, we tested a battery of LV constructs, including some with clinically relevant designs, and found that oncogene activation by promoter insertion is the most powerful mechanism of early vector-induced oncogenesis. SIN LVs disabled in their capacity to activate oncogenes by promoter insertion were less genotoxic and induced tumors by enhancer-mediated activation of oncogenes with efficiency that was proportional to the strength of the promoter used. On the other hand, when enhancer activity was reduced by using moderate promoters, oncogenesis by inactivation of tumor suppressor gene was revealed. This mechanism becomes predominant when the enhancer activity of the internal promoter is shielded by the presence of a synthetic chromatin insulator cassette. Our data provide both mechanistic insights and quantitative readouts of vector-mediated genotoxicity, allowing a relative ranking of different vectors according to these features, and inform current and future choices of vector design with increasing biosafety.
AB - Self-inactivating (SIN) lentiviral vectors (LV) have an excellent therapeutic potential as demonstrated in preclinical studies and clinical trials. However, weaker mechanisms of insertional mutagenesis could still pose a significant risk in clinical applications. Taking advantage of novel in vivo genotoxicity assays, we tested a battery of LV constructs, including some with clinically relevant designs, and found that oncogene activation by promoter insertion is the most powerful mechanism of early vector-induced oncogenesis. SIN LVs disabled in their capacity to activate oncogenes by promoter insertion were less genotoxic and induced tumors by enhancer-mediated activation of oncogenes with efficiency that was proportional to the strength of the promoter used. On the other hand, when enhancer activity was reduced by using moderate promoters, oncogenesis by inactivation of tumor suppressor gene was revealed. This mechanism becomes predominant when the enhancer activity of the internal promoter is shielded by the presence of a synthetic chromatin insulator cassette. Our data provide both mechanistic insights and quantitative readouts of vector-mediated genotoxicity, allowing a relative ranking of different vectors according to these features, and inform current and future choices of vector design with increasing biosafety.
UR - http://www.scopus.com/inward/record.url?scp=84897570147&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84897570147&partnerID=8YFLogxK
U2 - 10.1038/mt.2014.3
DO - 10.1038/mt.2014.3
M3 - Article
C2 - 24441399
AN - SCOPUS:84897570147
VL - 22
SP - 774
EP - 785
JO - Molecular Therapy
JF - Molecular Therapy
SN - 1525-0016
IS - 4
ER -