High expression of endogenous bcl-2 and bcl-xL in thymic lymphomas do not diminish their sensitivity to etoposide-induced apoptosis.
It was previously reported that thymic lymphomas of anti HY-TCR transgenic mice were resistant to ionomycin but were sensitive to 50 microM of etoposide. We selected lymphoma clones with strong expression of anti-apoptotic proteins Bcl-2 or Bcl-xL and found that in contrast to proteins encoded by exogenous genes in other model systems, over-expression of endogenous Bcl-2 and Bcl-xL proteins failed to protect against etoposide-induced apoptosis. Susceptibility of lymphoma cells was not diminished even to suboptimal concentration of 0.5 microM of etoposide. Treatment with etoposide did not decrease the ratio of anti-apoptotic Bcl-2 and Bcl-xL proteins to pro-apoptotic Bax protein. Results presented here suggest that high expression of Bcl-2 and Bcl-xL may not diminish susceptibility of T-cell lymphomas to chemotherapy with etoposide.
Matuszyk
J
J
Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw. matuszyk@immuno.iitd.pan.wroc.pl
Kalas
W
W
Cebrat
M
M
Strzadala
L
L
D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D005047:Etoposide / Q000494:pharmacology*; D008223:Lymphoma / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis* / Q000235:genetics; D013953:Thymus Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D051020:bcl-X Protein
D000972:Antineoplastic Agents, Phytogenic; C494812:Bcl2l1 protein, mouse; D019253:Proto-Oncogene Proteins c-bcl-2; D051020:bcl-X Protein; D005047:Etoposide