Establishment and characterization of a rare atypical chronic myeloid leukemia cell line NT-1.

Human leukemia cell lines are of great value in leukemia research. In this study, we established and described the biological characteristics of a rare atypical chronic myeloid (aCML) leukemia cell line (NT-1). Mononuclear cells were isolated from the bone marrow of a patient with atypical chronic myeloid leukemia (Ph(-)/bcr(-)/abl(-)), and were passaged by liquid culture. Cells were maintained without any cytokines for over 1 year, and named NT-1. This cell line was extensively characterized using morphological assays, flow cytometry, cytogenetic analysis, clonogenic culture, quantitative fluorescent PCR, short tandem repeating sequence PCR (STR-PCR) and array-CGH. Its tumorigenic capacity was also examined in nude mice. The NT-1 cell line had morphological features of chronic myeloid leukemia and major myeloid markers (CD13, CD33, CD11b). Additionally, NT-1 expressed progenitor cells and natural killer cell-related antigens such as CD34, CD117, CD56. Cytogenetic analysis initially demonstrated two abnormalities: 47, xx, +8 and 47, xx, +8 accompanied by t(5;12)(q31;p13) translocation. The one-year passage process did not alter the karyotype. NT-1 cells maintained the same morphology, immunophenotyping and cytogenetic features as primary leukemia cells, which was strongly supported by STR-PCR results. Neither Epstein-Barr virus nor mycoplasma was detected in the NT-1 line. In addition, NT-1 cells showed high tumorigenic capacity in nude mice. NT-1 is a new atypical chronic myeloid leukemia cell line with the +8 and t(5,12) translocation, and exhibits high tumorigenicity in nude mice. This new cell line provides a useful tool for the study of leukemogenesis.