Study On Reversal Of Multidrug Resistance In ABCB1-Overexpressing Leukemia By Ceritinib And Its Mechanism

Background/AimsMultidrug 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 is a selective ALK inhibitor and has been approved as the second-line treatment for ALK-positive non-small cell lung cancer.Our previous studies have showed that ceritinib can reverse the multidrug resistance in solid tumor cells by competing with anticancer drugs for the substrate binding site of ABCB1 and inhibiting the efflux activity of ABCB1 transporter.Moreover,it has been reported that the expression levels and functions of ABC transporters are vary in different races,tumor types,cells or tissues types.Therefore,we hypothesized that leukemia cells and solid tumor cells are also different in ABCB1-mediated drug resistance.To verify our hypothesis,in our experiments,we used the leukemia cell lines K562 and K562/adr to test whether ceritinib can also enhance the efficacy of anti-cancer drugs in human ABCB1 overexpression MDR leukemia as solid tumors.Methods:MTT assay was used to detect the cytotoxicity of drugs;The K562/adr nude mouse xenograft model was established to evaluate the efficacy of ceritinib to reverse ABCB1-mediated MDR in vivo;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.The primary leukemic cells were isolated by density gradient centrifugation.ResultsWe 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.Conclusions 1.Ceritinib reverses ABCB1-mediated multidrug resistance transporter in vitro.2.Ceritinib restored the sensitivity of doxorubicin on the K562/adr transplanted nude mice models without increasing the side effects of doxorubicin.3.Ceritinib can also reverse the ABCB1--mediated multidrug resistance in an ex vivo model of humans,providing a new therapeutic approach for the treatment of ABCB1-overexpressing MDR leukemia patients in future.