OBJECTIVE-To protect granulosa cells from chemotherapy-induced toxicity by retrovirusmediated multidrug resistance gene (MDR1) transfection.
DESIGN-Laboratory study.SETTING-Academic research laboratory in a university hospital.
INTERVENTION(S)-KK15immortalized murine granulosa cell line was transiently transduced with sf91m3 retrovirus vector carrying MDR1 cDNA that encodes P-glycoprtoein (P-gp). Transduced cells were selected with colchicine and treated with doxorubicin or paclitaxel for 24-72 hours. The expression and function of MDR1 and the mRNA expression of selected steroidogenesis enzymes were evaluated by flow cytometry, cell viability assays, Western blot, and RT-PCR.
MAIN OUTCOME MEASURE(S)-Viability of sf91m3-transduced KK15 cells after treatment with doxorubicin and paclitaxel.RESULT(S)-sf91m3-transduced KK15 demonstrated high expression of biologically active MDR1 as shown by flow cytometry analysis and immunoblotting using P-gp monoclonal antibody and Rhodamine 123 efflux assays. sf91m3-transduced KK15 exhibited significant resistance to toxicity of 10uM paclitaxel(p≤0.001). MDR1-transduced KK15 cells were also protected from doxorubicin toxicity (10nM to 2.5uM) as shown by cell viability assay (p≤0.02). Both flow cytometry and cell viability assay showed that the protection of KK15 from doxorubicin toxicity was lost at 5 uM of doxorubicin; equivalent to 500 times LD50 (p≥0.05). sf91m3-transduced KK15 showed normal mRNA expression of a panel of selected steroidogenesis enzymes.
CONCLUSION(S)-Retroviralgene delivery of human MDR1 inhibited chemotherapy-induced granulosa cell toxicity and offered chemoprotection in an in vitro model.