Alterations in immunoglobulin synthesis during adriamycin-induced apoptosis in mouse hybridoma cells

Changes in the immunoglobulin synthesis in mouse hybridoma 1F7 cell line following exposure to the anticancer drug adriamycin were studied. It was shown that adriamycin in concentrations up to 0.1 microgram/ml causes dose-dependent reversible enhancement of immunoglobulin heavy gamma 2b chain synthesis, and to a lesser extent, kappa light chain synthesis. Enhancement of gamma 2b heavy chain synthesis accompanies an increase in Ig gamma 2b mRNA levels. Enhancement of DNA-binding activity 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 G2/M phase of cell cycle. These changes in hybridoma cells preceded the onset of internucleosomal DNA fragmentation and appearance of morphological characteristics of apoptosis. These findings suggest, that differentiation-related processes occur during the latent phase of apoptosis induced by adriamycin in mouse hybridoma cells.