Usp9x knockdown diminished the chemosensitization role of WP1130. After transfection with usp9x siRNA or negative control, breast cancer cell lines (MDA-MB-231, MDA-MB-468 and Bcap-37) were exposed to cisplatin alone (0, 2, 4, 6, 8, 10 μg/mg) or in combination with WP1130 (2.5 µM). Viability of (A) MDA-MB-231, (B) MDA-MB-468, and (C) Bcap-37 cells was determined using CCK-8 assay.