HETEROGENEOUS RESPONSE TO THE GROWTH-FACTORS [EGF, PDGF (BB), TGF-ALPHA, BFGF, IL-2] ON GLIOMA SPHEROID GROWTH, MIGRATION AND INVASION

The effects of 5 different growth factors [EGF, PDGF(bb), TGF-alpha, b FGF and IL-2] were studied on tumour spheroids obtained from 5 differe nt human glioma cell lines (U-251MG, D-263MG, D-37MG, D-54MG, GaMG). T he expression of EGF and PDGF receptors as well as the endogenous prod uction of TGF-alpha and PDGF were studied by Northern blot analyses. A fter growth-factor-exposure, tumour spheroid volume growth, and direct ional cell migration from the spheroids were studied. In addition, tum our-cell invasion was studied in vitro, where foetal rat-brain aggrega tes were used as a target for the tumour cells. In all the assays a co mmon stimulator for most of the cell lines was EGF. The other growth f actors had a more heterogeneous stimulatory effect. Tumour-cell invasi on, cell growth and cell migration are biological properties which are not necessarily related to each other. This may explain why the tumou rs often responded differently to the growth factors in the various as say systems. Two of the cell lines studied were non-invasive (U-251MG, D-263MG). It is shown that these were stimulated both in the directio nal migration assay and in the spheroid-volume-growth assay. However, their non-invasive behaviour was not influenced by the growth factors studied. (C) 1994 Wiley-Liss, Inc.