Inhibition of survivin and aurora B kinase sensitizes mesothelioma cells by enhancing mitotic arrests.
OBJECTIVE
Survivin, a member of the inhibitor of apoptosis gene family, has also been shown to regulate mitosis. It binds Aurora B kinase and the inner centromere protein to form the chromosome passenger complex. Both Aurora B and survivin are overexpressed in many tumors. In this study, we examined whether irradiation affected survivin and Aurora B expression in mesothelioma cells, and how inhibition of these molecules affected radiosensitivity.


METHODS
ZM447439 and survivin antisense oligonucleotides were used to inhibit survivin and Aurora B kinase respectively. Western blot was performed to determine the expression of survivin, Aurora B, phosphorylated-histone H3 (Ser 10), and caspase cleavage. Multinucleated cells were counted using flow cytometry, and cell survival after treatment was determined using clonogenic assay.


RESULTS
At 3-Gy irradiation an increase was observed in levels of survivin and Aurora B as well as the kinase activity of Aurora B, with an increase in G2/M phase. The radiation-induced upregulation of these molecules was effectively attenuated by antisense oligonucleotides against survivin and a small-molecule inhibitor of Aurora B, ZM447439. Dual inhibition of survivin and Aurora B synergistically radiosensitized mesothelioma cells with a dose enhancement ratio of 2.55. This treatment resulted in increased formation of multinucleated cells after irradiation but did not increase levels of cleaved caspase 3.


CONCLUSIONS
Inhibition of survivin and Aurora B induces mitotic cell arrest in mesothelioma cells after irradiation. These two proteins may be potential therapeutic targets for the enhancement of radiotherapy in malignant pleural mesothelioma.
Kim
Kwang Woon
KW
Department of Radiation Oncology, Vanderbilt Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
Mutter
Robert W
RW
Willey
Christopher D
CD
Subhawong
Ty K
TK
Shinohara
Eric T
ET
Albert
Jeffrey M
JM
Ling
Geng
G
Cao
Carolyn
C
Gi
Young Jin
YJ
Lu
Bo
B
D064107:Aurora Kinase B; D064127:Aurora Kinases; D001549:Benzamides; D053148:Caspase 3 / Q000378:metabolism / Q000528:radiation effects; D002470:Cell Survival; D016195:G2 Phase / Q000528:radiation effects; D006657:Histones / Q000378:metabolism* / Q000528:radiation effects; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D008654:Mesothelioma / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy*; D008869:Microtubule-Associated Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism / Q000528:radiation effects; D008938:Mitosis / Q000187:drug effects*; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism / Q000528:radiation effects; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism / Q000528:radiation effects; D011799:Quinazolines; D011836:Radiation Tolerance / Q000187:drug effects; D000077022:Survivin; D015854:Up-Regulation / Q000528:radiation effects
C474722:4-(4-(N-benzoylamino)anilino)-6-methoxy-7-(3-(1-morpholino)propoxy)quinazoline; C107489:BIRC5 protein, human; D001549:Benzamides; D006657:Histones; D051034:Inhibitor of Apoptosis Proteins; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D016376:Oligonucleotides, Antisense; D011799:Quinazolines; D000077022:Survivin; C576921:AURKB protein, human; D064107:Aurora Kinase B; D064127:Aurora Kinases; D017346:Protein Serine-Threonine Kinases; D053148:Caspase 3