CONSTITUTIVE AND SELECTIVE EXPRESSION OF BASIC FIBROBLAST GROWTH-FACTOR IN HUMAN LEUKEMIA-CELL LINES

We have previously shown that basic fibroblast growth factor (bFGF) st imulates megakaryocytopoiesis and granulopoiesis in vitro and that nor mal haematopoietic cells and several leukaemic cell lines express FGF receptors. In this paper, we demonstrate by reverse transcriptase-medi ated polymerase chain reaction (RT-PCR) that bFGF mRNA is expressed in two leukaemia cell lines with megakaryocytic features (Meg-Ol and K56 2), in two lymphocytic cell lines (Hut 78 and CA) and in normal human peripheral blood mononuclear cells. In addition, the conditioned media of Meg-Ol, but not Dami, contained a potent fibroblast-stimulating ac tivity which could be neutralized by bFGF antibodies, Furthermore, bFG F antibody significantly inhibited the autocrine growth of Meg-OI cell s in vitro. However, we could not detect cell-associated 18 kDa bFGF o r HMW bFGF by immunofluorescence, immunoprecipitation or Western blott ing. These data indicate that bFGF is expressed by certain haematopoie tic cells and support further a role of this FGF prototype in haematop oiesis.