Establishment of a new Glivec-resistant chronic myeloid leukemia cell line, SNUCML-02, using an in vivo model

Abstract

Objective. In this study, we report a newly established chronic myeloid leukemia (CML) cell line, SNUCML-02, which is resistant to imatinib and describe its biological characteristics. Materials and Methods. Mononuclear cells were obtained from the bone marrow of a CIVIL patient in blast crisis and were cultured in Dulbecco`s modified Eagle`s medium/F12 containing 20% fetal bovine serum. After 2 months of primary culture, these cells were injected into nonobese diabetic/severe combined immune-deficient mice via tail vein. Eight weeks alter injection, mice were sacrificed and ex vivo culture was performed from the bone marrow cells isolated from the mice. The established cell line was named as SNUCML-02 and the biological features were characterized by cytogenetic analysis, fluorescence in situ hybridization, reverse transcriptase polymerase chain reaction. sequencing analysis, cell proliferation assay. and Western blot analysis. Results. Cytogenetic studies using conventional G-banding and fluorescent in situ hybridization of SNUCML-02 demonstrated classical Philadelphia chromosome, (9;22)(q34;q11.2), and other abnormalities, such as add(11)(q23), +19 and +der(9;22). SNUCML-02 has the same BCR-ABL, fusion transcript as was seen in K562 cells, but has no mutations in the ABL kinase domain. SNUCML-02 was more resistant to imatinib (STI571, Gleevec, Glivec) than other CML cell lines (K562. Kc122, and BV173). SNUCML-02 has constitutive activation of extracellular signal-regulated kinase phosphorylation. In addition, interleukin-3 induced phosphorylation and constitutively enhanced extracellular signal-regulated kinase phosphorylation was not inhibited by imatinib in SNUCML-02. Conclusion. SNUCML-02 is a new established cell line with a relatively high level of resistance to imatinib, which is useful for investigating the pathogenesis of CML progression, and will be useful in developing optimal therapeutic strategies for this ailment.