ESTABLISHMENT AND CHARACTERIZATION OF 2 NOVEL CYTOKINE-RESPONSIVE ACUTE MYELOID AND MONOCYTIC LEUKEMIA-CELL LINES, MUTZ-2 AND MUTZ-3

Human permanent leukemia cell lines represent powerful research tools in a multitude of investigations. The two new continuous leukemia cell lines MUTZ-2 and MUTZ-3 were derived from the peripheral blood of pat ients with acute myeloid leukemia (AML) FAB M2 and AML FAB M4. MUTZ-2 and MUTZ-3 cells have morphological and immunophenotypical features of myeloid and monocytic cells, respectively. While MUTZ-2 is negative, MUTZ-3 cells express the monocytic surface marker CD14, albeit weakly. The monocytic nature of MUTZ-3 cells is underlined by the expression of the monocyte-specific esterase (MSE), myeloperoxidase (MPO) and tar trate-resistant acid phosphatase (TRAP) enzymes; MUTZ-2 is negative fo r MSE and TRAP, but expresses MPO. For sustained cell growth, both cel l lines require constitutively the addition of cytokines to the cultur e medium and retain an absolute dependence on conditioned medium or re combinant growth factors for proliferation and survival. Incubation wi th single recombinant cytokines from a broad spectrum of growth factor s established that the strongest proliferation response of MUTZ-2 cell s was elicited by FLT-3 ligand, granulocyte colony-stimulating factor (G-CSF), macrophage CSF (M-CSF), interferon-gamma (IFN-gamma) and stem cell factor (SCF), whereas granulocyte-macrophage CSF (GM-CSF), M-CSF , interleukin-3 (IL-3) and SCF were the most effective growth factors in inducing proliferation of MUTZ-3. Both cell lines were proliferativ ely responsive to several further cytokines, however, to a lesser exte nt. Exposure to phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate (T PA) or the physiological all-trans retinoic acid (ATRA) had growth-inh ibitory and differentiation-inducing effects on both cell lines. Using a clonogenic cell recovery assay, both cell lines were found to be se nsitive to the chemotherapeutic drugs cytosine arabinoside (Ara-C) and daunorubicin (DNR), MUTZ-2 cells being more sensitive to both Ara-C a nd DNR treatment than MUTZ-3 cells. Chromosomal trisomies 8 and 10 wer e found in MUTZ-2 cells without any additional structural abnormalitie s. MUTZ-3 carries the rare, but recurrent AML-associated translocation (12;22)(p13;q11-q12) reflecting the karyotype of the original tumor. The main characteristics of these cell lines remained the same during about 1 year of continuous culture as well as after freezing and thawi ng. In summary, we established and characterized two new leukemia cell lines with myeloid or monocytic features which are growth factor-resp onsive, one of them carrying a unique chromosomal translocation. These cells will be of particular value for investigating the complex cytok ine network and molecular events caused by chromosomal aberrations.