Résumé
<p><b>OBJECTIVE</b>To investigate the effect of small interfering RNA (siRNA)-mediated COX-2 gene silencing in enhancing the chemosensitivity of KB/VCR cell lines.</p><p><b>METHODS</b>KB/VCR cells were trasnfected with COX-2 siRNA were examined for expressions of COX-2 and MDR-1 mRNAs with RT-PCR and for Rho-123 accumulation using flow cytometry. MTT assay was used to analyze the proliferation of the transfected KB/VCR cells.</p><p><b>RESULTS</b>Compared with the negative and blank control groups, COX-2 siRNA transfection resulted in significant growth inhibition of KB/VCR cells exposed to vincristine (P<0.01), down-regulated the expressions of COX-2 and MDR-1 mRNAs, and obviously increased Rho-123 accumulation in KB/VCR cells.</p><p><b>CONCLUSION</b>COX-2 gene silencing can enhance the chemosensitivity of KB/VCR cells to vincristine, the mechanism of which may involve down-regulated MDR-1 gene expression and inhibition of P-glycoprotein activity.</p>