Variant cell lines from the human promyelocyte line HL60

The continuous human promyeloid cell line HL60 may be induced to differentiate into neutrophils by the presence of 1.25% dimethylsulphoxide (DMSO) and related compounds [4]. When treated with 12-O-tetradecanoylphorbol-13-acetate (TPA), the cells exhibit many features characteristic of monocytes/macrophages [13]. In both cases, the induced HL60 cells lose their proliferative ability. The availability of this inducible cell line has led to an increasing number of studies aimed at dissecting the process of myeloid differentiation. However, the correct interpretation of such studies may only be reached through the use of appropriate cellular controls; specifically, variant HL60 cell lines which do not differentiate in response to the inducing agents. Here we report the isolation and characterization of two variant cell lines of HL60 which do not differentiate in the presence of 1.25% dimethylsulphoxide but still respond to TPA. Comparison of these HL60 variants with the parental line should facilitate the elucidation of molecular events which regulate myeloid differentiation.