Nanocarriers for siRNA delivery to overcome cancer multidrug resistance

Multidrug resistance(MDR)is an extremely complexed phenomenon in tumor chemotherapy and is one of the major obstacles for successful treatment.Discovery of RNA interference(RNAi)offers a new strategy with great potential to reverse MDR.Specific genes,which contribute to the emerging of MDR,can be silenced by RNAi.However,many natural barriers have to be overcome for efficient and safe delivery of siRNA.In recent years,the various kinds of nanocarriers,such as liposomes,cationic polymers,and inorganic materials,have been developed to deliver siRNA and show good results in reversing MDR.This review mainly summarizes the barriers in siRNA delivery and recent progress in designing nanotechnology-based siRNA delivery systems to overcome tumor MDR.