Insight on Multidrug Resistance and Nanomedicine Approaches to Overcome MDR.

Multidrug resistance (MDR) remains a major obstacle to ensure effective chemotherapy in cancer patients. Several factors could be associated with cancer cells' drug resistance such as overexpression of P-glycoprotein (P-gp), cancer stem cells (CSCs), defect in apoptosis, mutation and alteration in DNA repair pathways, angiogenesis, autophagy, and modulation in metabolic enzymes. Until now, drug efflux by ABC transporters has been a univocal and well-established mechanism of chemotherapeutic associated drug resistance. To explore the mechanics involved in ABC transporter associated drug resistance, many crucial studies have been conducted from identification of drug binding sites to elucidation of their structure. Due to our continuous battle with drug resistance, several strategies have been employed to combat MDR, including P-gp modulators, siRNAs, antibodies, as well as peptides. Furthermore, various nanoparticle and different effective combination nanomedicine strategies also suggest some exciting results. Thus, to improve nanomedicine approaches to overcome MDR, in this evolutionary review, we have focused on fundamentals of possible strategies as well as the latest accomplishments to reverse MDR.