The mortality of ovarian cancer stably ranks first in gynecological malignancies due to the lack of specific symptoms and diagnostic methods at an early stage. For most patients, the cancer cells had metastasized before they were diagnosed. As a result, 90% of them died of multidrug resistance (MDR) to chemotherapeutics. In our study, RNAi technology was introduced and applied to overcome this big problem. LAH4-L1, an amphipathic cationic polypeptide, was reported to have high transfection efficiency and was first selected by us to deliver siMDR1 for overcoming ovarian cancer cells MDR. In this research, LAH4-L1-siRNA nanocomplexes (LSCs) delivery system was designed via electrostatic interactions. The nanocomplexes could realize 87.3% MDR1 gene silence and 85% P-gp down-regulation on SKOV-3 cells. What's more, with the combination of chemotherapeutics, SKOV-3 cells growth inhibition can reach to 82.9%. We have also found that there was about 50% reduction on cells migration when MDR1 gene was down-regulated. Besides what have been mentioned above, physicochemical characteristics, cytotoxicity, pH responsivity, cells cycle, cellular uptake, and endosomal escape abilities were also studied in this research. In conclusion, lower cytotoxicity, higher down-regulation of targeted gene, and great cell inhibition, when combined with chemotherapeutics, all show the great potential of LSCs for the reversal of multidrug resistance on SKOV-3 cells in the future.
Keywords: MDR; nanocomplex; ovarian cancer; pH responsive peptides; siRNA.