Improved retroviral suicide gene transfer in colon cancer cell lines after cell synchronization with methotrexate

Background: cancer gene therapy by retroviral vectors is mainly limited by the level of transduction. retroviral gene transfer requires target cell division. cell synchronization,obtained by drugs inducing a reversible inhibition of dna synthesis,could therefore be proposed to precondition target cells to retroviral gene transfer. we tested whether drug-mediated cell synchronization could enhance the transfer efficiency of a retroviral-mediated gene encoding herpes simplex virus thymidine kinase (hsv-tk) in two colon cancer cell lines,dhdk12 and ht29. methods. synchronization was induced by methotrexate (mtx),aracytin (ara-c) or aphidicolin. gene transfer efficiency was assessed by the level of hsv-tk expression. transduced cells were driven by ganciclovir (gcv) towards apoptosis that was assessed using annexin v labeling by quantitative flow cytometry. results: dhdk12 and ht29 cells were synchronized in s phase with mtx but not ara-c or aphidicolin. in synchronized dhdk12 and ht29 cells,the hsv-tk transduction rates were 2 and 1.5-fold higher than those obtained in control cells,respectively. furthermore,the rate of apoptosis was increased two-fold in mtx-treated dhdk12 cells after treatment with gcv. conclusions: our findings indicate that mtx-mediated synchronization of target cells allowed a significant improvement of retroviral hsv-tk gene transfer,resulting in an increased cell apoptosis in response to gcv. pharmacological control of cell cycle may thus be a useful strategy to optimize the efficiency of retroviral-mediated cancer gene therapy. © 2011 finzi et al; licensee biomed central ltd.