ANTISENSE INHIBITION OF C-FES PROTOONCOGENE BLOCKS PMA-INDUCED MACROPHAGE DIFFERENTIATION IN HL60 AND IN FDC-P1 MAC-11 CELLS/

To gain some insight into the role of c-fes in macrophage differentiat ion, we have analyzed the ability of HL60 leukemic promyelocytic cells and FDC-P1/MAC-11 murine myeloid precursor cells to differentiate in response to phorbol esters after inhibition of c-fes function. Fes ina ctivation has been obtained by using oligodeoxynucleotides (ODN) compl ementary to the 5' region of c-fes mRNA and to 5' splice junctions of c-fes primary transcript. After 5 days (d) in culture, in several sepa rate experiments performed with different ODN preparations, a complete inhibition of c-fes expression was observed in HL60 and in FDC-P1/MAC -11 cells. No perturbation of cell growth was evident in our experimen tal conditions in both cell lines after c-fes inhibition. Furthermore, in HL60 cells lacking c-fes product, an almost complete downregulatio n of the alpha 4 beta 1 fibronectin receptor occurred. However, in bot h cell lines, the induction of macrophage differentiation by phorbol e aters resulted in an almost complete maturation arrest as evaluated by morphological, cytochemical, immunological criteria, and by the cytof luorimetric cell cycle analysis. A loss of the adhesion capacity of bo th myeloid cell lines, when compared to terminally differentated macro phages, was also observed. These results suggest that HL60 and FDC-P1/ MAC-11 cells, when treated with phorbol 12-myristate 13-acetate, requi re c-fes protein expression to activate the genetic program underlying macrophage differentiation. (C) 1997 by The American Society of Hemat ology.