Leukemias following retroviral transfer of multidrug resistance 1 (MDR1) are driven by combinatorial insertional mutagenesis

TY - JOUR

T1 - Leukemias following retroviral transfer of multidrug resistance 1 (MDR1) are driven by combinatorial insertional mutagenesis

AU - Modlich, Ute

AU - Kustikova, Olga S

AU - Schmidt, Manfred

AU - Rudolph, Cornelia

AU - Meyer, Johann

AU - Li, Zhixiong

AU - Kamino, Kenji

AU - von Neuhoff, Nils

AU - Schlegelberger, Brigitte

AU - Kuehlcke, Klaus

AU - Bunting, Kevin D

AU - Schmidt, Sonja

AU - Deichmann, Annette

AU - von Kalle, Christof

AU - Fehse, Boris

AU - Baum, Christopher

PY - 2005/6/1

Y1 - 2005/6/1

N2 - Previous studies have demonstrated leukemic complications in mice after high-copy retroviral gene transfer of the multidrug resistance 1 (MDR1) cDNA, encoding a membrane-located efflux pump expressed in hematopoietic stem cells. In contrast, no such complications or MDR1-associated alterations of hematopoiesis were observed in numerous other studies exploring MDR1 gene transfer into cell lines, mice, dogs, nonhuman primates, and human subjects. Here, we show that leukemias associated with retroviral expression of MDR1 depend on high vector dose, and involve the selection of clones with combinatorial insertional mutagenesis of proto-oncogenes or other signaling genes. Compared with insertion patterns in normal long-term repopulating hematopoietic cells, such hits were overrepresented in leukemic clones, pointing to a causal role. A similar constellation of insertion sites was also observed in a leukemia arising after high-copy retroviral gene transfer of a fluorescent protein. Spectral karyotyping demonstrated additional chromosomal translocations in a subset of cases, indicative of secondary genetic instability. We also show that insertional mutants can be amplified in vitro prior to transplantation. On the basis of these findings, we suggest the use of preclinical dose-escalation studies to define a therapeutic index for retroviral transgene delivery.

AB - Previous studies have demonstrated leukemic complications in mice after high-copy retroviral gene transfer of the multidrug resistance 1 (MDR1) cDNA, encoding a membrane-located efflux pump expressed in hematopoietic stem cells. In contrast, no such complications or MDR1-associated alterations of hematopoiesis were observed in numerous other studies exploring MDR1 gene transfer into cell lines, mice, dogs, nonhuman primates, and human subjects. Here, we show that leukemias associated with retroviral expression of MDR1 depend on high vector dose, and involve the selection of clones with combinatorial insertional mutagenesis of proto-oncogenes or other signaling genes. Compared with insertion patterns in normal long-term repopulating hematopoietic cells, such hits were overrepresented in leukemic clones, pointing to a causal role. A similar constellation of insertion sites was also observed in a leukemia arising after high-copy retroviral gene transfer of a fluorescent protein. Spectral karyotyping demonstrated additional chromosomal translocations in a subset of cases, indicative of secondary genetic instability. We also show that insertional mutants can be amplified in vitro prior to transplantation. On the basis of these findings, we suggest the use of preclinical dose-escalation studies to define a therapeutic index for retroviral transgene delivery.

KW - ATP Binding Cassette Transporter, Subfamily B, Member 1/administration & dosage

KW - Animals

KW - Gene Dosage

KW - Gene Transfer Techniques/adverse effects

KW - Genes, MDR/genetics

KW - Genetic Therapy/adverse effects

KW - Genetic Vectors/adverse effects

KW - Leukemia/etiology

KW - Mice

KW - Mice, Inbred C57BL

KW - Mutagenesis, Insertional

KW - Retroviridae/genetics

KW - Translocation, Genetic

U2 - 10.1182/blood-2004-11-4535

DO - 10.1182/blood-2004-11-4535

M3 - SCORING: Journal article

C2 - 15713797

VL - 105

SP - 4235

EP - 4246

JO - BLOOD

JF - BLOOD

SN - 0006-4971

IS - 11

ER -