High expression of multidrug resistance-associated protein 1 (MRP1) in tumor cells reduces effectiveness of chemotherapy drugs. In this study, we screened MRP1 interfering RNA (MRP1-siRNA) molecules that are able to reverse etoposide (VP16) resistance in multidrug resistance rat glioma cell line C6/VP16, and identified one siRNA molecule that is able to effectively deplete the expression of MRP1 gene and reverse tumor cells resistance to etoposide. Since siRNA instability limits its application in treatment of diseases, we next tested silencing effect of chitosan-MRP1-siRNA nanoparticles and found that the nanoparticles with N:P ratio 175 are able to effectively inhibit MRP1 mRNA and protein expression. Our data demonstrate that chitosan can be used as siRNA carrier for high efficient gene silencing in tumor cells.
Keywords: Etoposide; Multidrug resistance-associated protein 1; Rat glioma cells; Small interfering RNA.