The pleiotropic effect of TPA on in vitro invasion/migration of glioma and melanoma cell lines

The invasion/migration of two cell lines, melanoma (MEW) and glioma (BT5C), and their counterparts treated for prolonged time with TPA were studied. On Western blots both cell lines expressed α, βI protein kinase C isoforms, whereas βII and γ were not detected. The down-regulation of α and βI PKC was observed in glioma cells after long treatment with TPA, whereas the same treatment of melanoma cells did not lead to PKC downregulation. The down-regulation of PKC was accompanied by stimulation of cell migration/invasion through Transwell chambers coated with collagen IV or fibronectin. In the case of melanoma cells treated with TPA, whose PKC was not down-regulated, the inhibition of migration/invasion was observed. The invasive properties of studied cells did not correlate with any conventional PKC isoform expression.