WEE1 inhibitor, AZD1775, overcomes trastuzumab resistance by targeting cancer stem-like properties in HER2-positive breast cancer


Translational Oncology Research (TORQUE), Advocate Aurora Health Research Institute, Aurora Neuroscience Innovation Institute, Aurora St. Luke's Medical Center, Comprehensive Breast Care Center, Aurora Sinai Medical Center


Although trastuzumab has greatly improved the outcome of HER2-positive breast cancer, the emergence of resistance hampers its clinical benefits. Trastuzumab resistance is a multi-factorial consequence predominantly due to presence of cancer stem-like cells (CSCs). AZD1775, a potent anti-cancer agent targeting WEE1 kinase to drive tumor cells with DNA damage to premature mitosis, has previously shown high efficacies when targeting different cancers with a well-tolerated cytotoxic profile, but has not been evaluated in trastuzumab-resistant (TrR) breast cancer. We sought to investigate the effect of AZD1775 on cancer stem-like cell (CSC) properties, apoptosis, cell cycle regulation in TrR breast cancer. Our study for the first time demonstrated that AZD1775 induces apoptosis and arrests TrR cells at G2/M phase. More importantly, AZD1775 effectively targeted CSC properties by suppressing MUC1 expression levels. AZD1775 administration also induced apoptosis in our in-house patient-derived tumor cell line at passage 0, implying its significant clinical relevance. These findings highlight the potential clinical application of AZD1775 in overcoming trastuzumab resistance in breast cancer.

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