Figure 4. Treatment with lapatinib sequesters BRCA1 away from its nuclear repair substrates to the cytosol in triple negative breast cancer cells.

(A–C) Cells were subjected to 1 µM lapatinib treatment for 16 hours and BRCA1 location was assessed by subcellular fractionation. Lapatinib induced cytosolic translocation of BRCA1 in (A) MDA-MB-231, (B) MDA-MB-453 and (C) MDA-MB-468 cells. Histone H1 and α-tubulin were used to test the purity of the nuclear and cytosolic fractions respectively. Quantification of BRCA1 levels was performed via densitometry. Shown is the representative data of three independent experiments (mean +/− SEM, **p<0.01).