Astaxanthin Co-treatment with Low Dose Methotrexate Increases the Cell Cycle Arrest and Ameliorates the Methotrexate-induced Inflammatory Response in NALM-6.

Methotrexate (MTX), an antimetabolite agent, is widely used for acute lymphoblastic leukemia treatment, despite its association with significant organ dysfunction. Astaxanthin (AST) is a natural carotenoid which has recently been emerged as a promising anti-tumor and anti-inflammatory agent. In this study, we aimed to evaluate the effectiveness of astaxanthin and low-dose methotrexate co-treatment in acute lymphoblastic leukemia cell line. The expression of Dihydrofolate reductase (DHFR), Thymidylate synthase (TYMS), apoptotic, anti-apoptotic as well as inflammatory genes was investigated using qRT-PCR. Flow cytometry was performed for cell cycle quantitative evaluation. Clonogenic assay was used to assess NALM6 cells proliferation capacity following treatment with AST, MTX, and co-treatment. To compare the antioxidant property of each group, the ferric ion reducing anti-oxidant power assay was performed. A reduction in viability was observed in the presence of MTX, AST, and their combined treatment. Both AST alone and in combination with MTX caused cell cycle arrest and a reduction in the expression of DHFR and TYMS. While MTX, AST, and their combination could reduce STAT3 and BCL-XL gene expression, they could act as positive regulators for the expression of BAX and CASP3, TNFα, and IL6. AST and MTX co-treatment inhibited the colony formation ability. FRAP assay also revealed that AST and AST+MTX increased the antioxidant capacity. Our data suggests that AST can improve MTX treatment efficacy and their combination therapy can be considered as a promising strategy for the management of acute lymphoblastic leukemia.