INTERACTION WITH FIBRONECTIN REGULATES CYTOKINE GENE-EXPRESSION IN HUMAN-MELANOMA CELLS

Our study was aimed at investigating whether interaction of human mela noma cells with the extracellular matrix (ECM) protein fibronectin (FN ) could regulate lymphokine gene expression. Serum-deprived cells (qui escent condition) of a metastatic melanoma cloned line were cultured e ither on uncoated or on FN- or BSA-coated surfaces. By means of revers e transcriptase-polymerase chain reaction (RT-PCR), we analyzed mRNA e xpression of 4 cytokines-interleukin (IL)-1 alpha IL-1 beta, IL-6 and IL-8 and 9 growth factors-endothelial cell growth factor (ECGF), basic fibroblast growth factor (bFGF), fibroblast growth factor (FGF)-5, HS T, keratinocyte growth factor (KGF), transforming growth factor (TGF)- alpha, TGF-beta 1, TGF-beta 2 and TGF-beta 3. When cultured on FN, mel anoma cells expressed IL-1 alpha and IL-6 transcripts in addition to I L-1 beta, IL-8, ECGF, TGF-beta 1, TGF-beta 2 and TGF-beta 3, already p resent in quiescent cells. Amplification parameters to achieve semi-qu antitative RT-PCR were then determined for each detectable factor, thu s allowing us to measure a selective enhancement of mRNA levels for IL -1 alpha, IL-6, IL-8 and TGF-beta 2 upon interaction with FN by quiesc ent melanoma cells. This augmented expression was inhibited by an anti -integrin beta 1 chain monoclonal antibody (MAb). Moreover, the amount s of IL-6, IL-8 and IL-beta produced in the supernatants, as assessed by ELISA, correlated with the corresponding mRNA expression. Extension of this analysis to the other 5 human primary and metastatic melanoma lines confirmed the ability of FN to selectively up-regulate only IL- 6 and IL-8 secretion. Our data indicate that FN is able to modulate ex pression and secretion of a defined subset of lymphokines in human mel anoma. (C) 1996 Wiley-Liss, Inc.