Restoration of BRCA1 partially rescues from sensitivity to DZNep. (a) Detection of the human BRCA1 allele by PCR amplification of exon 11 in the reconstituted subclones KB1PR-3.12 E3 and F4. The human breast cancer cell line T47D was used as a positive control. (b) EZH2 protein levels of (untreated) K K 14cre; B rca 1F/F; p 53F/F(KB1P), KB1PR and K 14cre;Brca1w.t/w.t; p 53F/F(KP) cell lines were analysed by western blotting. Corresponding Ezh2 mRNA levels of KB1P, KB1PR and KP cell lines were measured by quantitative RT-PCR (shown as fold induction relative to Hprt). (c) Representative growth inhibition curves for BRCA1-deficient cell lines (KB1P, in blue), BRCA1-proficient cell lines (KP, in red) and two clones of a BRCA1-reconstituted cell line (KB1PR E3 and F4, in purple) treated with 3-deazaneplanocin A (DZNep). A serial dilution of DZNep was added to the cells and cell viability was measured five days later (mean ± standard error of the mean). (d) EZH2 protein levels of hBRCA1-reconstituted KB1P cells 48 hours after treatment with DZNep or siRNAs targeting EZH2.