MDR1Gene Transfer Using a Lentiviral SIN Vector Confers Radioprotection to Human CD34⁺Hematopoietic Progenitor Cells

Abstract

Tumor radiotherapy with large-field irradiation results in an increase in apoptosis of the radiosensitive hematopoietic stem cells (CD34(+)). The aim of this study was to demonstrate the radioprotective potential of MDR1 overexpression in human CD34(+) cells using a lentiviral self-inactivating vector. Transduced human undifferentiated CD34(+) cells were irradiated with 0-8 Gy and held in liquid culture under myeloid-specific maturation conditions. After 12 days, MDR1 expression was determined by the rhodamine efflux assay. The proportion of MDR1-positive cells in cells from four human donors increased with increasing radiation dose (up to a 14-fold increase at 8 Gy). Determination of expression of myeloid-specific surface marker proteins revealed that myeloid differentiation was not affected by transduction and MDR1 overexpression. Irradiation after myeloid differentiation also led to an increase of MDR1-positive cells with escalating radiation doses (e.g. 12.5-16% from 0-8 Gy). Most importantly, fractionated irradiation (3 x 2 Gy; 24-h intervals) of MDR1-transduced CD34(+) cells resulted in an increase in MDR1-positive cells (e.g. 3-8% from 0-3 x 2 Gy). Our results clearly support a radioprotective effect of lentiviral MDR1 overexpression in human CD34(+) cells. Thus enhancing repopulation by surviving stem cells may increase the radiation tolerance of the hematopoietic system, which will contribute to widening the therapeutic index in radiotherapy.

MiR-593 mediates curcumin-induced radiosensitization of nasopharyngeal carcinoma cells via MDR1

“…Therefore, blocked MDR1 may enhance the efficacy of chemotherapy and reverse radioresistance in patients. Maier et al (29) confirmed that a protective effect of retroviral overexpression of MDR1 is increasing the radiotolerance of haematopoietic cells and the related apoptosis gene was downregulated. In the present study, it was also observed that MDR1 was a radioresistant factor which could be downregulated by mir-593.…”

Expression of multidrug resistance 1 and multidrug resistance-related protein 1 in C57BL/6 mice treated with benzene

“…Lentivirus-mediated MDR1 overexpression in human CD34 + cells may increase the radiation tolerance of the hematopoietic system (Maier et al, 2008). Transduction of the MDR1 gene into hematopoietic stem cells suggests a bone marrow-protective effect with no serious side-effects observed (Takahashi et al, 2007).…”

F2A sequence linking MGMTP140K and MDR1 in a bicistronic lentiviral vector enables efficient chemoprotection of haematopoietic stem cells

“…VIII) was described previously. 31,38 For cloning of the other five bicistronic vectors see Supplementary Methods.…”

“…38 HL-60 and K562 cells were transduced (with an multiplicity of infection of 3) and selected by vincristine (20 nM) or BCNU (40mm) according to standard operating procedures. 31 HSCs were pre-stimulated as described previously; 31 then cells were transduced three times (each with an multiplicity of infection of 10) during 24 h as described previously 31 for experiments shown in Figure 3 or according to the protocol of Santoni de Sio et al 39 for experiments shown in Figure 4 with Iscove's modified Dulbecco's medium supplemented with 300 ng ml À 1 human stem cell factor, 300 ng ml À 1 fms-like tyrosine kinase receptor-3 ligand, 100 ng ml À 1 thrombopoietin, 60 ng ml À 1 interleukin-3 (all from R&D systems, Wiesbaden, Germany), 8 mg ml À 1 polybrene (Sigma-Aldrich) and 0,75 mM MG-132 (Merck4Biosciences, Darmstadt, Germany).…”