Apoptosis induced in human osteosarcoma cells is one of the mechanisms for the cytocidal effect of Ad5CMV-p53.
Recombinant adenovirus Ad5CMV-p53 induced a strong cytocidal effect in Saos-LM2 cells. This cell line, derived from human osteosarcoma Saos-2 cells, has a homozygous deletion of the p53 gene. By using immunocytochemical and Western blot analyses, we demonstrated that Ad5CMV-p53 effectively infected Saos-LM2 cells at multiplicities of infection of 10 to 50 plaque-forming units/cell and mediated a high-level expression of the exogenous wild-type p53 protein in the cells. Growth of the infected cells was greatly suppressed whereas that of mock- or control virus-infected cells was not. Because wild-type p53 induces apoptosis in certain types of cells, we studied DNA fragmentation in situ in the Ad5CMV-p53-infected Saos-LM2 cells by terminal deoxynucleotidyl transferase assays, which yielded positive nuclear staining. Further analysis of the Ad5CMV-p53-infected Saos-LM2 cells by light and electron microscopy demonstrated that the cells underwent the characteristic morphological changes of apoptosis such as plasma-membrane blebbing, nuclear condensation, and fragmentation. These changes were not observed in mock- or control virus-infected cells. Our results on Saos-LM2 cells indicate that apoptosis induced by Ad5CMV-p53 may be one of the mechanisms underlying the cytocidal effect of Ad5CMV-p53.
Wang
J
J
Department of Thoracic and Cardiovascular Surgery, University of Texas M.D. Anderson Cancer Center, Houston 77030, USA.
Bucana
C D
CD
Roth
J A
JA
Zhang
W W
WW
D000260:Adenoviruses, Human / Q000235:genetics*; D017209:Apoptosis / Q000235:genetics; D001859:Bone Neoplasms / Q000235:genetics / Q000473:pathology*; D003587:Cytomegalovirus / Q000235:genetics*; D017353:Gene Deletion; D015967:Gene Expression Regulation, Viral; D016158:Genes, p53; D005822:Genetic Vectors; D006801:Humans; D008854:Microscopy, Electron; D009368:Neoplasm Transplantation; D012516:Osteosarcoma / Q000235:genetics / Q000473:pathology*; D011993:Recombinant Fusion Proteins / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000502:physiology*
D011993:Recombinant Fusion Proteins; D016159:Tumor Suppressor Protein p53