SYNTHETIC OCTAPEPTIDE PYROGLU-ASP-ASP-SER-ASP-GLU-GLU-ASN PROMOTES DIFFERENTIATION IN PROMYELOCYTIC HL-60 CELL-LINE

The activity of the octapeptide pyroGlu-Asp-Asp-Ser-Asp-Glu-Glu-Asn in the control of cell growth and differentiation of human myeloblastic leukemia cells HL-60 is reported. Treatment with peptide slightly slow s down the rate of cellular proliferation and this effect becomes more evident in cells grown for several weeks in the presence of the effec tor. An enhanced effect (40-50% inhibition respect to the control) is found in reversibly permeabilized cells and after 1% DMSO is added to the medium. Moreover the presence of peptide markedly increases the pe rcentage of cells differentiated by DMSO and RA. The effect in DMSO-in duced cells is more evident than that observed in RA-induced cells. Th is in agreement with our hypothesis that DMSO facilitates the peptide entry and its effect is due to an intracellular action.