Changes in glucocorticoid-induced apoptosis and in expression of Bcl-2 protein during long-term culture of thymic lymphoma

• Authors: M. Kobzdej , J. Matuszyk , E. Ziolo , L. Strzada?a , L. Strzada?a
• Languages of publication: EN

Abstracts

EN

Lymphomagenesis is a multistep process progressively freeing transformed thymocytes from external regulatory signals, i. e. thymic developmental program controlling growth, differentiation or apoptosis. Here we report that cells of thymic lymphoma overexpressing Ras/Raf proteins, initially resistant to TCR-dependent apoptosis but sensitive to dexamethasone- and etoposide-induced cell death, became insensitive to dexamethasone after long-time culture. That transition correlated with a strong increase in the expression of the anti-apoptotic Bcl-2 protein. Interestingly, lymphoma cells were still sensitive to p53-mediated apoptosis induced by etoposide. It suggests that the anti-apoptotic activity of Bcl-2 is correlated with a resistance to glucocorticoid-induced apoptosis but not to p53-mediated apoptosis. The sequence of mutations in the process of lymphomagenesis seems to be composed of at least 3 main hits which equip the cells with independence from external mitogenic signals (activation of Ras/Raf), resistance to inducers of apoptosis (activation of Bcl-2) and generation of cellular heterogeneity (deletion of p53) important in tumor progression.

Keywords

EN

APOPTOSIS; DEXAMETHASONE; THYMIC LYMPHOMA

Discipline

• IMMUNOLOGY: IMMUNOLOGY

• Journal: Archivum Immunologiae et Therapiae Experimentalis
• Year: 2000
• Volume: 48
• Issue: 1
• Pages: 43-46

Contributors

author

M. Kobzdej

author

J. Matuszyk

author

E. Ziolo

author

L. Strzada?a

author

L. Strzada?a

• Document Type: SHORT COMMUNICA
• Publication order reference: M. Kobzdej, Laboratory of Cellular Immunology, Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-114 Wroclaw, Poland