Reversing cancer multidrug resistance: insights into the efflux by ABC transports from in silico studies

One of the greatest threats to cancer treatment is the development, by some tumors, of resistance to the pharmacological action of several structurally unrelated cytotoxic agents—multidrug resistance (MDR). As P-glycoprotein (P-gp) is one of the most studied ATP-dependent efflux pumps that are frequently involved in drug efflux from cancer cells, the development of MDR modulators with the ability to inhibit P-gp efflux is considered a promising approach for overcoming MDR.However, the development of P-gp modulators have been hampered due to the absence of knowledge on the intrinsic molecular aspects by which efflux occurs, namely the specific steps that correlates drug recognition, ATP binding and efflux-related conformational changes. Experimental evidences for these processes are also difficult to obtain and only provide small pieces of information that need to be assembled for better comprehension of a wider and complex process that is drug efflux. A promising alternative relies on cutting-edge computational techniques to provide new insights on key aspects that are determinant to understand how P-gp efflux can be effectively reversed. With the contribution of ligand-based or structure-based computational methods, P-gp drug efflux is slowly becoming a dynamic and reactive process rather than a simple response to drug binding, with the complex architecture ofABC transporters playing a determinant role not only in drug recognition but in the coordination of ATP-driven conformational changes that ultimately drives drug efflux. The major enlightenments that computational studies provided toward a better comprehension of MDR and P-gp efflux phenomena are hereby described.

Ricardo J. Ferreira 1, Maria-José U. Ferreira 1, and Daniel J. V. A. dos Santos 1,2∗

1 Instituto de Investigação do Medicamento (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Lisboa, Portugal

2 REQUIMTE, Department of Chemistry & Biochemistry, Faculty of Sciences, University of Porto, Porto, Portugal

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