Enhancing Activity of Anticancer Drugs in Multidrug Resistant Tumors by Modulating P-Glycoprotein through Dietary Nutraceuticals

Multidrug resistance is a principal mechanism by which tumors become resistant to structurally andfunctionally unrelated anticancer drugs. Resistance to chemotherapy has been correlated with overexpression ofp-glycoprotein (p-gp), a member of the ATP-binding cassette (ABC) superfamily of membrane transporters. P-gpmediates resistance to a broad-spectrum of anticancer drugs including doxorubicin, taxol, and vinca alkaloidsby actively expelling the drugs from cells. Use of specific inhibitors/blocker of p-gp in combination with clinicallyimportant anticancer drugs has emerged as a new paradigm for overcoming multidrug resistance. The aimof this paper is to review p-gp regulation by dietary nutraceuticals and to correlate this dietary nutraceuticalinduced-modulation of p-gp with activity of anticancer drugs.