ALTERATIONS IN IMMUNOGLOBULIN-SYNTHESIS DURING ADRIAMYCIN-INDUCED APOPTOSIS IN MOUSE HYBRIDOMA CELLS

Changes in the immunoglobulin synthesis in mouse hybridoma 1F(7) cell line following exposure to the anticancer drug adriamycin were studied . It was shown that adriamycin in concentrations up to 0.1 mu g/ml cau ses dose-dependent reversible enhancement of immunoglobulin heavy gamm a(2b) chain synthesis, and to a lesser extent, kappa light chain synth esis. Enhancement of gamma(2b) heavy chain synthesis accompanies an in crease in Ig gamma(2b) mRNA levels. Enhancement of DNA-binding activit y of another B-cell specific protein, octamer transcription factor Oct -2 was also observed. Cell cycle analysis revealed accumulation of the ADR-treated cells in G(2)/M phase of cell cycle. These changes in hyb ridoma cells preceded the onset of internucleosomal DNA fragmentation and appearance of morphological characteristics of apoptosis. These fi ndings suggest, that differentiation-related processes occur during th e latent phase of apoptosis induced by adriamycin in mouse hybridoma c ells. (C) 1997 Academic Press Limited.