Mapping out Health

THE HUMAN CELL LINE CCRF-CEM was derived by Foley et al. (1965) from the peripheral blood of a patient with acute lymphoblastic leukaemia (ALL). When tested by Norman & Thompson (1977) CCRF-CEM was only partially sensitive to glucocorticoids, but Clone C7, isolated from the parental cell line, was lysed by pharmacological concentrations of glucocorticoids. The availability of a steroid-sensitive human lymphoid cell line made it possible to study interactions between steroids and other chemotherapeutic drugs under conditions more appropriate to their clinical usage. Some preliminary results obtained with CEM-C7 cells have already been described (Norman et al., 1 978). This paper presents the results of further investigations into the interaction of prednisolone with drugs used in the treatment ofALL. The drugs used were 6-mercaptopurine (MP), methotrexate (MTX), cytosine arabinoside (Ara-C) and daunomycin (DMN). CEM-C7 cells were maintained in continuous culture in Medium RPMI 1640 supplemented with 10% foetal calf serum (Flow Laboratories). In fresh medium cell growth was exponential between 105 and 5 x 106 cells/ml. Solutions of prednisolone and other drugs (Sigma Chemical Co.) were prepared fresh for each experiment. Prednisolone was added to cell suspensions from a stock solution in 10% or 1% ethanol; an equivalent volume of ethanol was added to control cells. Ara-C and Accepted 2 June 1981