Figure 1. Human colon cancer cells exhibit differential sensitivity to PARP-1 inhibition.

(a) CRC cell lines FET, HCT116 p21^−/−, HCT-116, SW480, SW620, and Caco-2 were treated with PARPi for 3 (triangle) and 4 (square) days and IC₅₀ determined (**p < 0.01). The experiment was performed at least three independent trials with at least three technical replicates. (b) Untreated CRC cell lines were harvested, protein extracts were prepared, separated and immunoblotted with anti-BRCA1 antibody as described in Methods. The experiment was repeated at least three times. Quantification of protein band intensity was performed by ImageJ software (*p < 0.05 and **p < 0.01).