[Antiapoptotic oncogene bcl-2 induces a program of senescence in E1A + c-Ha-ras-transformants treated with adriamycin].
Introduction of bcl-2 gene in EIA + c-Ha-ras-transformed rat embryo fibroblasts, which are unable to be arrested after damaging influences and possess high proapoptotic sensitivity, results not only in suppression of cell death but also in re-establishment of cell cycle block following DNA damage and serum starvation. Flow cytometry showed that E1A + c-Ha-ras + bcl-2-transformants treated with DNA-intercalator adriamycin are capable of being arrested at G1/S boundary for a long time (for less than 5 days). According to the growth curve data, the number of Bcl-2-overexpressing cells remanins constant for a week of cultivation with adriamycin. Clonogenic efficacy of E1A + c-Ha-ras + bcl-2-cells is brought to no already in 16 h after adriamycin addition. Apoptotic death, revealed by oligonucleosomic fragmentation of DNA, as well as cell death, occurring due to mitotic catastrophe, after adriamycin treatment are almost absent in Bcl-2-overexpressing transformants, as compared with parental E1A + c-Ha-ras-transformants. Bcl-2 introduction in E1A + c-Ha-ras-transformants is accompanied by a rise of SA beta-Gal (Senescence Associated beta-Galactosidase) activity, which is commonly considered to be a marker of cell senescence. Adriamycin treatment of E1A + c-Ha-ras + bcl-2-transformants results in a much higher rise in SA beta-Gal activity, as compared with untreated cells. Co-immunoprecipitation experiments demonstrated the introduction of Bcl-2 to result in formation of Bcl-2 complexes with early region E1A oncoproducts, which are thought to be responsible for proapoptotic susceptibility of E1A-expressing transformants. The data obtained lead to suggestion that bcl-2 transfer to E1A + c-Ha-ras-transformants may induce a switch from the cell death program on the program of senescence after DNA damage, due, presumably, to Bcl-2 interaction with the apoptosis activator the viral oncoprotein E1A.
Neliudova
A M
AM
Zubova
S G
SG
Aksenov
N D
ND
Pospelov
V A
VA
Pospelova
T V
TV
D017500:Adenovirus E1A Proteins / Q000235:genetics*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000235:genetics; D002461:Cell Line, Transformed; D016922:Cellular Senescence / Q000187:drug effects* / Q000235:genetics; D003001:Cloning, Molecular; D004317:Doxorubicin / Q000494:pharmacology*; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D005434:Flow Cytometry; D019254:Genes, bcl-2; D011905:Genes, ras; D006801:Humans; D007364:Intercalating Agents / Q000494:pharmacology*; D011519:Proto-Oncogenes; D051381:Rats; D001616:beta-Galactosidase / Q000378:metabolism
D017500:Adenovirus E1A Proteins; D007364:Intercalating Agents; D004317:Doxorubicin; D001616:beta-Galactosidase