Lycorine attenuated proliferation and induced apoptosis on imatinib-resistant K562 cell by inhibiting autophagy.

Background: Tyrosine kinase inhibitor (TKI) resistance is a significant factor exacerbating the burden on chronic myeloid leukemia (CML) patients and impacting clinical efficacy. The main goal is to offer new insights into overcoming drug resistance in treating CML.

Methods: Imatinib (IM) resistant K562/IM cells were generated using gradient induction. Responses to IM, lycorine, and autophagy modulators were assessed using CCK-8. Protein expression of Beclin-1, Atg5, LC3, Caspase-3, P62, Bax, Bcl-2, and P-gp was detected using Western blot. Lycorine-induced apoptosis and cell cycle changes were evaluated through flow cytometry, while autophagy alterations were detected using monodansylcadaverine (MDC) staining. In the K562/IM mice model, non-obese diabetic severe combined immunodeficent (NOD-SCID) mice were subcutaneously inoculated with K562/IM cells. After 17 days of lycorine injection, assessments included tumor size, hematoxylin-eosin (HE) staining, and Ki67 expression.

Results: After 72 h of IM treatment, K562/IM cells showed a 55.86-fold increase in drug resistance compared to K562 cells. Lycorine treatment for 24 h inhibited cell proliferation and induced G0/G1 phase cell cycle arrest and apoptosis in both K562 and K562/IM cells. MDC staining indicated reduced autophagy in K562/IM cells, mitigated by lycorine. In vivo experiments demonstrated reduced tumor size and Ki67 proliferation index in the lycorine treatment group (K562+L, K562/IM+L) compared to the control group, particularly in the drug-resistant group. However, no significant change in Ki67 was observed in the K562 group after lycorine treatment.

Conclusion: In summary, K562/IM cells displayed heightened autophagy levels compared to K562 cells. Lycorine effectively impeded the proliferation of K562/IM cells through diverse mechanisms, including reduced autophagy, enhanced apoptosis, and induced cell cycle arrest.