Establishment and characterization of an arsenic-sensitive monoblastic leukaemia cell line (SigM5)

Few human monoblastic cell lines have been characterized to date. We have e stablished the SigM5 cell line from a patient with acute monoblastic leukae mia (FAB M5a). Original leukaemic cells had a karyotype of 47,XY,+8, wherea s the cell line showed a stemline clone of 81,XX,Y,Y,1,4,6,7,+8,+8,9,10,10, 11,13,16,19[cp], with a minor sideline also present, Cytochemical staining was strongly positive with alpha-naphthylbutyrate acetate esterase, particu late positive with Sudan black and weakly positive for myeloperoxidase. Cel ls were positive for CD13, CD15, CD18, CD23, CD33, CD38, CD45, CD68 and mye loperoxidase, CD14 expression was 3-15%. SigM5 constitutively secreted inte rleukin (IL)-2, IL-8, IL-10, tumour necrosis factor (TNF)-alpha, ferritin, lysozyme, N-elastase and neopterin upon stimulation with interferon (IFN)-g amma. Cells expressed the proinflammatory mediator macrophage migration inh ibitory factor (MIF). All NADPH oxidase subunits were constitutively presen t, but nitroblue tetrazolium reduction was only detectable upon activation with IFN-gamma. SigM5 monoblasts were sensitive to arsenic trioxide (AS(2)O (3)) previously not described to induce apoptosis in monoblastic cells. Dif fering considerably in morphology, immunophenotype and sensitivity to arsen ics from the widely used cell lines U937, HL-60 and THP-1, SigM5 is a new m onoblastic cell line useful for studying leukaemogenesis, monocyte differen tiation and tumour cell susceptibility to arsenic compounds.