Ceritinib Enhances the Efficacy of Substrate Chemotherapeutic Agent in Human ABCB1-Overexpressing Leukemia Cells In Vitro, In Vivo and Ex-Vivo.

Background/aims: Multidrug resistance (MDR) triggered by ATP binding cassette (ABC) transporters, such as ABCB1, ABCC1, and ABCG2, is a key obstacle for successful cancer chemotherapy. There is currently no FDA-approved MDR modulator that can be used in clinic. Ceritinib, a selective ALK inhibitor, has been approved as the second-line treatment for ALK-positive non-small cell lung cancer. Here, we examined the role of ceritinib in leukemia associated MDR in therapy.

Methods: The cell proliferation was detected by MTT assay. The flow cytometry was used to detect the expression of cell surface protein and to detect the accumulation and efflux of rhodamine 123 (Rh123) or doxorubicin (Dox) in cells. The RT-PCR and Western blot were performed to detect the gene expression and protein expression levels, respectively.

Results: We found that ceritinib enhanced the efficacy of substrate chemotherapeutic agent in ABCB1-overexpressing K562/adr leukemia cells both in vitro and in vivo models, but neither in sensitive parental K562 leukemia cells nor in ABCC1-overexpressing HL-60/adr leukemia cells. Mechanistically, ceritinib significantly increased the intracellular accumulation of Rh123 or Dox but did neither alter ABCB1 expressions at both protein and mRNA levels nor block the phosphorylations of AKT and ERK1/2 at the concentration of MDR reversal. Importantly, ceritinib also increased the intracellular accumulation of Dox and enhanced the efficacy of Dox in primary leukemia cells in ex-vivo.

Conclusion: Our results suggested that ceritinib enhanced the efficacy of substrate chemotherapeutic agent on inhibition of leukemia cell growth in vitro, in vivo and ex-vivo, which linked to block ABCB1 function, pumping out its substrate conventional chemotherapeutic agent, thereby increasing the intracellular accumulation. These suggest the combination of ceritinib and substrate chemotherapeutic drugs maybe an effective treatment of resistant leukemia patients with ABCB1-mediated MDR.