To target the pivotal BCR/ABL oncoprotein in chronic myeloid leukemia (CML) cells, tyrosine kinase inhibitors (TKIs) are utilized as landmark achievements in CML therapy. However, TKI resistance and intolerance remain principal obstacles in the treatment of CML patients. In recent years, drug repositioning provided alternative and promising perspectives apart from the classical cancer therapies, and promoted anthelmintic mebendazole (MBZ) as an effective anti-cancer drug in various cancers. Here, we investigated the role of MBZ in CML treatment including imatinib-resistant CML cells. Our results proved that MBZ inhibited the proliferation and induced apoptosis in CML cells. We found that MBZ effectively suppressed BCR/ABL kinase activity and MEK/ERK signaling pathway by reducing p-BCR/ABL and p-ERK levels with ABL1 targeting ability. Meanwhile, MBZ directly targeted the colchicine-binding site of β-tubulin protein, hampered microtubule polymerization and induced mitosis arrest and mitotic catastrophe. In addition, MBZ increased DNA damage levels and hampered the accumulation of ataxia-telangiectasia mutated and DNA-dependent protein kinase into the nucleus. This work discovered that anthelmintic MBZ exerts remarkable anticancer effects in both imatinib-sensitive and imatinib-resistant CML cells in vitro and revealed mechanisms underlying. From the perspective of drug repositioning and multi‐target therapeutic strategy, this study provides a promising option for CML treatment, especially in TKI-resistant or intolerant individuals.

Keywords: Chronic myeloid leukemia, Drug repositioning, Imatinib resistance, Mebendazole