Abstract
Background/Aim: There is no established standard chemotherapy after administration of the combination endocrine plus CDK4/6 inhibitor therapy for luminal-type breast cancer. We used patient-derived xenograft (PDX) models to determine the antitumor activity of eribulin and capecitabine after endocrine therapy plus CDK4/6 inhibitor. Materials and Methods: We examined the antitumor activity of fulvestrant, palbociclib, eribulin, and capecitabine in 4 luminal-type breast cancer PDX models (OD-BRE-0188, -0438, -0450, -0745). In OD-BRE-0438, we determined the antitumor activity of chemotherapy after fulvestrant–palbociclib treatment. We also performed immunohistochemical analysis to explore the effects of treatment on E-cadherin in tumor tissues. Results: Fulvestrant, fulvestrant-palbociclib and chemotherapy had antitumor activity in the 4 PDX models. In OD-BRE-0438 (the most resistant to fulvestrant–palbociclib), eribulin had superior antitumor activity to capecitabine after fulvestrant plus palbociclib. Only eribulin tended to increase E-cadherin expression. Conclusion: Eribulin had superior antitumor activity to capecitabine after fulvestrant–palbociclib in the OD-BRE-0438 model.
- CDK4/6 inhibitor
- eribulin mesylate
- luminal-type breast cancer
- patient-derived xenograft model
- reversal of epithelial-mesenchymal transition
- preclinical trial
- Received October 30, 2020.
- Revision received November 15, 2020.
- Accepted November 16, 2020.
- Copyright © 2020 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.