Radiation-induced apoptosis of tumor cells is facilitated by inhibition of the interaction between Survivin and Smac/DIABLO.
To investigate the mechanism of radioresistance of solid tumor cells, we created two expression vectors encoding Survivin mutants, T34A and D53A. When T34A and D53A were overexpressed in NIH3T3, A549 and HeLa cells, radiation-induced apoptosis was significantly enhanced. Furthermore, we examined the binding capability of Survivin with Smac/DIABLO in the cells that overexpressed these mutants. Coimmunoprecipitation analysis revealed that mutant form of Survivin, D53A and T34A could bind to Smac/DIABLO, but with much less affinity compared to the authentic form. These results suggest that radiation-induced apoptosis of tumor cells is increased by inhibition of the interaction between Survivin and Smac/DIABLO through overexpression of T34A and D53A.
Ogura
Aki
A
Laboratory of Radiation Biology, Department of Environmental Veterinary Medical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Kita 18 Nishi 9, Sapporo 060-0818, Japan.
Watanabe
Yasuko
Y
Iizuka
Daisuke
D
Yasui
Hironobu
H
Amitani
Makoto
M
Kobayashi
Saori
S
Kuwabara
Mikinori
M
Inanami
Osamu
O
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis / Q000528:radiation effects*; D051017:Apoptosis Regulatory Proteins; D020169:Caspases / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism; D005822:Genetic Vectors; D006367:HeLa Cells; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D008928:Mitochondria / Q000201:enzymology / Q000528:radiation effects; D024101:Mitochondrial Proteins / Q000378:metabolism*; D009154:Mutation; D041681:NIH 3T3 Cells; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D009369:Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy*; D010766:Phosphorylation; D011836:Radiation Tolerance; D015398:Signal Transduction / Q000528:radiation effects*; D000077022:Survivin; D013997:Time Factors; D014162:Transfection; D014965:X-Rays
D051017:Apoptosis Regulatory Proteins; C107489:BIRC5 protein, human; C412403:DIABLO protein, human; D051034:Inhibitor of Apoptosis Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008869:Microtubule-Associated Proteins; D024101:Mitochondrial Proteins; D009363:Neoplasm Proteins; D000077022:Survivin; D045304:Cytochromes c; D020169:Caspases