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. 2011 Feb 24;74(4):567–573. doi: 10.1021/np100429s

Figure 3.

Figure 3

Austocystin D modulates MDR1 activity in vitro and in cells. (a) Effect of austocystin D (ausD) and MDR1 substrates verapamil (ver) and vinblastine (vin) on the ATP hydrolysis by membranes containing MDR1 in the presence (dashed lines) or absence (solid lines) of 1 μM MDR1 inhibitor cyclosporin A (csA). Austocystin D, verapamil, and vinblastine each activated MDR1 ATP hydrolysis that was inhibitable by cyclosporin A. (b) Effect of 10 μM austocystin D, 40 μM verapamil, and 10 μM cyclosporin A on the retention of calcein in HCT-15 cells. Austocystin D behaved similarly to verapamil and cyclosporin A to inhibit calcein-AM efflux and thereby increase intracellular calcein fluorescence relative to vehicle (DMSO)-treated cells. (c, d) Effect of austocystin D and verapamil on (c) calcein-AM efflux and (d) growth in HCT-15 cells. Vertical bars represent SEM, representative experiment shown.