The HL-60 cell line is a human leukemia cell line that has been used for laboratory research on blood cell formation and physiology. HL-60 proliferates continuously in suspension culture in nutrient and antibiotic chemicals. The doubling time is about 36–48 hours. The cell line was derived from a 36-year-old woman who was originally reported to have acute promyelocytic leukemia at the MD Anderson Cancer Center.[1] HL-60 cells predominantly show neutrophilic promyelocytic morphology. Subsequent evaluation, including the karyotype that showed absence of the defining t(15;17) translocation, concluded that HL-60 cells are from a case of AML FAB-M2 (now referred to as AML with maturation (WHO)).[2]
Proliferation of HL-60 cells occurs through the transferrin and insulin receptors, which are expressed on cell surface. The requirement for insulin and transferrin is absolute, as HL-60 proliferation immediately ceases if either of these compounds is removed from the serum-free culture media.[3] With this line, differentiation to mature granulocytes can be induced by compounds such as dimethyl sulfoxide (DMSO), or retinoic acid. Other compounds like 1,25-dihydroxyvitamin D3, 12-O-tetradecanoylphorbol-13-acetate (TPA) and GM-CSF can induce HL-60 to differentiate to monocytic, macrophage-like and eosinophil phenotypes, respectively.
The HL-60 cultured cell line provides a continuous source of human cells for studying the molecular events of myeloid differentiation and the effects of physiologic, pharmacologic, and virologic elements on this process. HL-60 cell model was used to study the effect of DNA topoisomerase (topo) IIα and IIβ on differentiation and apoptosis of cells[4] and is especially useful in dielectrophoresis studies,[5] which require an aqueous environment with suspended and round cells. Furthermore, these cells have been used in order to investigate whether intracellular calcium plays a role in caspase activation induced by reactive oxygen species.[6]
Chromatin and gene expression profiling in HL-60 cells and differentiated cells derived from these has been performed recently.[7]