Figure 3. Specific ion transport inhibitors blocked amebic cytotoxicity in UMUC3 cells.

Inhibitors of ion channels hits from the RNAi screen were tested for the ability to block amebic cytotoxicity in vitro in UMUC3 cells. Cells were treated for 30 minutes at concentrations shown. We tested washout of inhibitors (+Washout +EH) relative to no washout(+Drug +EH). E. histolytica trophozoites were added at a ratio of 1:5 trophozoites to host cells. The addition of E. histolytica resulted in a 1:2 dilution of the inhibitors (concentrations prior to dilution are shown). LDH release was measured after 30 minutes. IC₅₀ was determined by non-linear regression of the log₁₀ of the inhibitor concentration vs. normalized cytotoxicity. IC₅₀ determinations excluded drug concentrations that resulted in toxicity to UMUC3 cells in the absence of E. histolytica.