BACKGROUNDMost of gynecologic malignancies are sensitive to chemotherapy. Myelosuppression is the main dose-related toxicity of many chemotherapeutic drugs. The human multidrug resistance (mdr1) gene is well known for its ability to confer drug resistance. This study aimed to explore the feasibility of expression and resistance of mdr1 gene transduction into human placenta mesenchymal stem cells (P-MSCs) by retrovirus vector.

METHODSHuman P-MSCs were isolated from trypsin-digested term placentas, and their immunophenotypes and differentiation potential were evaluated. Human P-MSCs were transduced by reconstructed retroviral vector containing the mdr1 gene and green fluorescent protein (GFP) reporter gene. The integration and expression of the mdr1 gene were observed indirectly by the expression of GFP, and fluorescence-activated cell sorter was used to evaluate the functional activity of permeability glycoprotein (P-gp) encoded by the mdr1 gene. The stimulating test was made in vitro to show pleiotropic drug resistance of transfected cells.

RESULTSThe isolated, cultured and expanded P-MSCs expressed stem cell markers such as CD29, CD44 and CD73, and showed osteogenic and adipogenic differentiation potentials under appropriate conditions. The expression of P-gp in the non-transfected P-MSCs cells was (0.4 +/- 0.1)%, but increased to (28.1 +/- 4.7)% after gene transfection (P < 0.01). And positive staining of P-gp located mainly at cell membrane and cytoplasm. Accumulation and extrusion assays showed that P-gp expressed by the transfected cells had pump-functional activity and could efflux daunomycin out of cells. The analysis of cell survival confirmed that transfected P-MSCs had a characteristic of multidrug resistance with a significant increase in the resistance to anticancer agents.

CONCLUSIONSTransfer and expression of human mdr1 gene mediated by retrovirus vector conferred P-MSCs drug resistance. It might provide a new alternative to chemoprotection strategies.