In conclusion, our study demonstrated that systemic administration of HA-PEI/HA-PEG/MDR1 siRNA CD44 targeted nanoparticle and paclitaxel represent an important advance and this strategy can be effective in enhancing the sensitivity of MDR cells to paclitaxel and to overcome drug resistance in MDR ovarian cancer. This evidence concerns the gene ABCB1 and ovarian cancer.