Fig. 4.

E3 MMAE and MMAF drug conjugates are toxic to prostate cancer, but not normal cells. (A) Structures of E3 aptamer conjugated to maleimide-caproyl-valine-citrulline-p-aminobenzylcarbamate-MMAE or maleimidocaproyl-MMAF. (B) Viability of PC-3, 22Rv1, and VCaP prostate cancer cells or normal PrEC cells treated with MMAE-E3 and MMAE-C36 or (C) MMAF-E3 and MMAF-C36. Cells were incubated with increasing concentrations of aptamer–drug conjugates and viability determined at 144 h. Data shown are the average of three to four individual experiments. **P ≤ 0.0074, ***P ≤ 0.0003, ****P < 0.0001 versus control C36 conjugates.