Human lung tumors express different types of growth-factor receptors and co
rresponding ligands that might modulate several biological functions such a
s proliferation, differentiation, adhesion, and chemotaxis. In the present
study, we have investigated the expression of different growth-factor recep
tors and their ligands in 5 established human lung-cancer cell lines. Using
RT-PCR, we found that IGF-III mannose-6-phosphate (M6P), c-met, EGF and c-
kit receptors are expressed in 5/5 human lung-cancer cell lines. In order t
o investigate the biological function of these receptors, we performed Boyd
en-chamber assays using various growth factors as chemo-attractants. Human
non-small-cell-lung-cancer cells (non-SCLC) migrated to recombinant human (
rh)IGF I and IGF II at concentrations ranging from 1 to 1000 ng/ml, to HGF
at 10 to 100 ng/ml, to EGF at 1 to 100 ng/ml and SCF at 1 to 50 ng/ml. In a
ddition, we performed Boyden-chamber assays using U-1810-, U-1752- and Wart
derived serum-free conditioned medium as chemo-attractants. Serum-free con
ditioned medium stimulated migration of producer cells in a dose-dependent
manner. The autocrine motility stimulating effect of U-1810-derived serum-f
ree conditioned medium could be inhibited by 50% in the presence of neutral
izing ahIGF-II antibodies in the assay, suggesting a possible autocrine mot
ility loop in vitro. Int. J. Cancer 82:338-345, 1999. (C) 1999 Wiley-Liss,
Inc.