Notch induces cell cycle arrest and apoptosis in human erythroleukaemic TF-1 cells

ObjectiveNotch signalling is known to promote hematopoietic stem cell self-renewal and to influence the lineage commitment decisions of progenitor cells. The purpose of this study was to investigate the mechanism of Notch-induced apoptosis in the erythroleukaemic cell line TF-1, and in primary cord blood CD34+ cells.MethodsRetroviral constructs containing constitutively active forms of Notch as well as components of the Notch signalling pathway were used to transduce cells and their effect on cell cycle kinetics and apoptosis assayed by immunostaining for the S-phase marker Ki67 and Annexin V.ResultsWe found that TF-1 cells undergo cell cycle arrest followed by apoptosis in a cytokine-independent manner in response to active Notch. Transduction of TF-1 cells with known targets of Notch signalling, Deltex1, HES1 and HERP2, showed that Notch-induced cell cycle arrest was not mediated by these proteins. However, analysis of cell cycle gene expression revealed that Notch signalling was associated with an up-regulation of IFI16 expression in TF-1 cells and in primary cord blood CD34+ cells.ConclusionThese data demonstrate that, in the context of TF-1 cells, Notch signalling can induce cell cycle arrest and apoptosis.