Combined treatment of zingerone and nilotinib induces cytotoxicity and reverses nilotinib resistance in chronic myeloid leukemia cells via inhibition of the PI3K signaling.

Abstract

Introduction: Tyrosine kinase inhibitors (TKIs) have revolutionized the treatment of chronic myeloid leukemia (CML); however, TKI resistance remains a persistent challenge. This study investigates the effects of zingerone on CML cell growth and nilotinib resistance.

Methods: K562 and LAMA84 cells were treated with zingerone (5-100 μM) or nilotinib (1-50 nM), and cytotoxicity was assessed using cell counting Kit-8 assay. Nilotinib-resistant cells (K562R, LAMA84R) were generated through gradual exposure to increasing nilotinib concentrations (1-10 nM) over six months. Subsequently, cells were treated with 10 μM zingerone and/or 5 nM nilotinib. Cell survival and apoptosis were measured by Trypan blue staining and flow cytometry. Protein levels of Bcr-Abl, apoptotic markers and PI3K pathway components were analyzed by Western blotting.

Results: Zingerone, nilotinib and their combination reduced parental CML cell survival and increased apoptosis. Resistant cells showed no significant response to nilotinib alone, confirming acquired resistance. However, the addition of zingerone markedly reduced survival and increased apoptosis in these resistant cells. The combination of zingerone and nilotinib increased levels of cleaved PARP, cleaved caspase-3, -9 and -8, while decreasing Bcl-2. Zingerone alone or in combination with nilotinib also reduced phosphorylation of PI3K, AKT and mTOR in resistant cells.

Conclusion: Zingerone enhances the inhibitory effects of nilotinib on CML cell survival and overcomes nilotinib resistance by suppressing the PI3K pathway.