Figure 2. APE1/Ref-1 redox function specific inhibitors decrease cell number in a concentration dependent manner.

PC-3 (A), C4-2 (B), LNCaP (C) and E7 (D) cell lines were treated with increasing concentrations of redox-specific inhibitor APX3330, more potent analogue APX2009, and inactive analogue RN7-58 for 5 days. The cells were fixed and stained with methylene blue and measured via spectrophotometry. IC₂₅ and IC₅₀ were determined as the concentrations of drug at which there was a 25% and 50% reduction in absorbance compared to vehicle control (DMSO) and were used for subsequent experiments. n = 3. EC50s were compared between the drugs: ^* denotes p < 0.05 drug EC50 versus RN7-58, while ¶ denotes p < 0.05, APX3330 versus APX2009.