DIFFERENTIAL CYTOTOXIC EFFECTS OF GAMMA-LINOLENIC ACID ON MG-63 AND HELA-CELLS

Gamma-linolenic acid (GLA) inhibited cell proliferation in MG-63 and H eLa cells. Different morphological lesions were present in dividing ce lls; abnormal spindle formation in MG-63 cells and chromosome hypercon densation in HeLa cells. Different types of cell death were also prese nt in interphase cells, no apoptosis but only 6% pycnosis in MG-63 cel ls and 90% apoptosis in HeLa cells. In MG-63 cells immunofluorescence showed segregation of nucleoli components, abnormal spindle formation and decreased labelling of microtubuli during interphase. In HeLa inte rphase cells prominently labelled abnormally arranged microtubuli were observed. The effects of GLA on protein synthesis in synchronized cel ls mere determined with [S-35]-methionine incorporation and SDS-PAGE. Decreased protein synthesis in both G(1)- and S-phase MG-63 cells was present. In S-phase HeLa cells, proteins of similar or equal to 40, 92 and 150 kD were markedly expressed. Signalling mechanisms involved in cell proliferation and cell death may be differently affected in MG-6 3 and HeLa cells.