"Combination treatments of imatinib with astaxanthin and crocin efficiently ameliorate antioxidant status, inflammation and cell death progression in imatinib-resistant chronic myeloid leukemia cells"

Abstract

Background: Imatinib resistance remains a major obstacle in the treatment of chronic myelogenous leukemia (CML). Crocin (CRC) and astaxanthin (ATX) are phytochemicals with anti-cancer properties.

Aims: This study aimed to explore the effects of combination treatment of Imatinib with CRC and ATX on Imatinib-resistant K562 (IR-K562) cells.

Methods and results: After the establishment of IR-K562 cells, growth inhibitory activity was determined by the MTT assay. To test the regeneration potential, a colony formation assay was performed. Cell cycle analyses were examined by flow cytometry. Cell injury was evaluated by lactate dehydrogenase (LDH) leakage. Real-time PCR was applied to assess the expression of IL6, TNF-α, STAT3, BAD, CASP3, TP53, and Bcl-2 genes. Caspase-3 activity was determined by a colorimetric assay. Antioxidant activity was measured using a diphenylpicrylhydrazyl (DPPH) assay. After 48 h of treatment, ATX (IC₅₀ = 30µM) and CRC (IC₅₀ = 190µM) significantly inhibited cell proliferation and colony formation ability, induced G1 cell cycle arrest and cell injury, upregulated the expression of apoptosis-associated genes, and downregulated the expression of anti-apoptotic and inflammatory genes. The combination of IM with ATX and/or CRC synergistically reduced cell viability (combination index [CI] < 1).

Conclusion: Our data suggest that IM shows better therapeutic efficacy at lower doses when combined with ATX and/or CRC.

Keywords: Astaxanthin; Chronic myeloid leukemia; Crocin; Drug resistance; Imatinib; K562 cells.