Recent Trends in Nanomedicine-Based Strategies to Overcome Multidrug Resistance in Tumors

SIMPLE SUMMARY: Cancer chemotherapy results in poor treatment response due to increased tumor resistance. There is a need to develop novel nanoparticle-based strategies to overcome resistance and improve therapeutic response. Nanomedicine-based strategies include the nanoparticle-/liposome-based delivery of drugs and siRNA to downregulate the genes causing resistance and the use of natural substances such as chemosensitizers to improve response to therapy. ABSTRACT: Cancer is the leading cause of economic and health burden worldwide. The commonly used approaches for the treatment of cancer are chemotherapy, radiotherapy, and surgery. Chemotherapy frequently results in undesirable side effects, and cancer cells may develop resistance. Combating drug resistance is a challenging task in cancer treatment. Drug resistance may be intrinsic or acquired and can be due to genetic factors, growth factors, the increased efflux of drugs, DNA repair, and the metabolism of xenobiotics. The strategies used to combat drug resistance include the nanomedicine-based targeted delivery of drugs and genes using different nanocarriers such as gold nanoparticles, peptide-modified nanoparticles, as well as biomimetic and responsive nanoparticles that help to deliver payload at targeted tumor sites and overcome resistance. Gene therapy in combination with chemotherapy aids in this respect. siRNA and miRNA alone or in combination with chemotherapy improve therapeutic response in tumor cells. Some natural substances, such as curcumin, quercetin, tocotrienol, parthenolide, naringin, and cyclosporin-A are also helpful in combating the drug resistance of cancer cells. This manuscript summarizes the mechanism of drug resistance and nanoparticle-based strategies used to combat it.