Abstract
Current therapeutic strategies used in many types of cancer are confronted with the major problem of multidrug resistance (MDR) that can be acquired through several mechanisms. To overcome this limitation, new therapeutic options are being explored involving state-of-the-art technologies. In this respect, small- interfering RNA (siRNA) technology offers the possibility to block the expression of genes that are involved in the MDR development, improving the therapeutic index of anticancer drugs. Nanocarriers are promising delivery systems for small molecule drugs as well as for nucleic acids aiming to target specifically the cancer cells and to counteract MDR. Several types of organic and inorganic nanocarriers will be discussed in this review, together with their advantages and limitations in delivery of targeted siRNAs and cytotoxic drugs, using in vivo and in vitro experiments. Although siRNA-anticancer drug co-delivery employing nanocarriers seems to be associated with a higher antitumor activity than single drug or nucleic acid administration, more studies are needed to evaluate the efficacy and the toxicity of various nanoparticle delivery systems.
Keywords: Multidrug resistance (MDR), nanocarriers, siRNA, drug delivery systems, co-delivery, liposomes, micelleplexes, inorganic nanoparticles.
Graphical Abstract