Nanotechnology applied to overcome tumor drug resistance.

Emerging multidrug resistance (MDR) to chemotherapy is a major obstacle in successfully treating malignant diseases. Nanotechnology provides an innovative and promising alternative strategy compared to conventional small molecule chemotherapeutics to circumvent MDR. This review focuses on recent literature examples of nanotechnology applications to overcome MDR. The advantages and limitations of various nanotechnologies are discussed as well as possible approaches to overcome the limitations. Developing a practical nanotechnology-based drug delivery system requires further studies of the tumor microenvironment, the mechanisms of MDR to chemotherapy, the optimal dosage regimen of anticancer drugs and/or siRNA, the transport kinetics of nanocarriers in tumor stroma and the pharmacokinetics of drug-loaded nanocarriers within MDR tumor cells.