Human malignant fibrous histiocytomas in vitro: Growth characteristics andtheir association with expression of mRNA for platelet-derived growth factor, transforming growth factor-alpha and their receptors

Eight human malignant fibrous histiocytomas were examined in vitro, in orde r to relate their growth properties to mRNA expression for platelet-derived growth factor (PDGF), PDGF receptor (PDGF-R) transforming growth factor-al pha (TGF-alpha) and the epidermal growth factor receptor (EGF-R). Reverse t ranscriptase-polymerase chain reaction (RT-PCR) showed that all cell lines expressed mRNA for PDGF-R alpha and/or PDGF-R beta; six cell lines expresse d mRNA for the PDGF-A chain, with one cell line coexpressing PDGF-B chain m RNA; seven cell lines expressed mRNA for TGF-alpha whereas six cell limes e xpressed EGF-R mRNA. Conditioned medium from three cell lines contained PDG F; none of the cell lines released TGF-alpha. Two cell lines grew without s erum requirements; whereas both expressed mRNA for PDGF, PDGF-R, TGF-alpha and EGF-R other cell lines, unable to grow without serum, showed the same c ombination of growth factor/growth factor receptor expression. The two cell lines able to grow without serum were also shown to be stimulated by the a ddition of PDGF-BB. These findings show that simultaneous expression of mRN A for a growth factor and its receptor does not necessarily imply an autocr ine or paracrine loop. However, two of our cell Pines fulfil the requiremen ts of possible PDGF-related autocrine and paracrine regulation. (C) 1998 El sevier Science Ltd. All rights reserves.