Reversin 121 is a hydrophobic peptide chemosensitizer that can reverse P-glycoprotein-mediated multidrug resistance. It binds to the P-glycoprotein multidrug transporter (MDR1) with a Kd value of 77 nM. Reversin 121 modulates P-glycoprotein ATPase activity in Sf9 insect cell membranes expressing human MDR1, plasma membrane vesicles from multidrug-resistant cells, and reconstituted proteoliposomes as well as in a variety of MDR1-expressing intact tumor cells.
