Chinese Herbal Medicines as Reversal Agents for P-glycoprotein-mediated Multidrug Resistance in Tumors

Multidrug resistance(MDR) is the major reason for failure of human cancer chemotherapy.One of the main underlying mechanisms of MDR is the over-expression of P-glycoprotein(P-gp),an ATP-dependent membrane transporter protein encoded by MDR1 gene.P-gp extrudes a spectrum of anticancer drugs from cancer cells and decreases effective intracellular drug concentrations,therefore leads to drug tolerance of cancer cells.P-gp modulators restore chemosensitivity of cancer cells through inhibiting transport function or cellular expression of P-gp.Chinese medicines have been used for treatment of cancer for thousand years.This review provides a brief introduction of Chinese medicines that exhibited activity in reversing P-gp-mediated MDR in cancers.