Cancer science 2018 03 30() doi 10.1111/cas.13593
Tyrosine kinase Src is overexpressed and activated in various tumors, including breast cancer, and is supposed to promote cancer formation and development. Src inhibitors are recently developed and have shown efficacy in breast cancer as single agent or in combination with anti-HER2 antibodies or chemotherapy. Unfortunately, the potency of Src inhibitor is limited by the development of drug resistance. In our study, we established a Src inhibitor saracatinib-resistant breast cancer cell line (SKBR-3/SI) for the first time and by evaluating mRNA expression profile, we first found that plasminogen activator inhibitor-1 (PAI-1) was upregulated in saracatinib-resistant cells compared to the parent cells. Further study demonstrated that PAI-1 might induce saracatinib resistance in breast cancer cells by increasing the secretion of chemokine (C-C motif) ligand 5 (CCL5). Besides, functional assays showed PAI-1 and CCL5 overexpression promoted cell proliferation and migration in breast cancer cells, while inhibition of PAI-1 and CCL5 decreased cell proliferation and migration in saracatinib-resistant cells. Moreover, we also showed that targeting PAI-1 or CCL5 could reverse saracatinib resistance, which deserves more attention in clinical settings. This article is protected by copyright. All rights reserved.