Interferon-alpha inhibits the DNA synthesis induced by PDGF and EGF in cultured meningioma cells.

The growth of meningioma in vivo may be mediated by a growth factor. We evaluated inhibitory effect of IFN-alpha on DNA synthesis promoted by PDGF and EGF on meningioma cell cultures. Eight cases of meningioma were tested for the expression of PDGF receptor. The effects of PDGF AA, PDGF BB, EGF and TGF-beta1 on five meningioma cell cultures were investigated by measuring 3H-thymidine incorporation during 24 hours of incubation with the growth factors under serum-free culture conditions. The incorporation of 3H-thymidine was elevated in all of the five tested tumor cell cultures after the addition of PDGF BB and EGF. Maximal stimulation was observed on three cultures with EGF and two cultures with PDGF BB. Under the same culture conditions, simultaneous incubation with IFN-alpha inhibited the 3H-thymidine incorporation promoted by PDGF and EGF. Our results indicate the inhibitory effect of IFN-alpha both on DNA synthesis promoted by PDGF and EGF, and on the meningioma cell proliferation. The present study also demonstrates the inhibitory effect of TGF-beta 1 in meningioma cell culture.