Aurora-a contributes to radioresistance by increasing NF-kappaB DNA binding.
Aurora-A, a serine/threonine kinase that is overexpressed in certain human cancer cell lines, plays an important role in mitotic progression. Aurora-A has also been reported to be involved in the activation of nuclear factor kappa B (NF-kappaB). The purpose of the present study was to identify the role of Aurora-A in the radiation-induced activation pathway of NF-kappaB. Wild-type and Aurora-A knockdown (Aurora-A(KD)) HeLa cells were irradiated with 4 Gy of gamma rays and the EMSA, luciferase reporter gene assay and immunoblot analysis were performed. The siRNA-based gene knockdown and overexpression system was adopted to elucidate the role of Aurora-A in radiation-induced NF-kappaB pathway activation. The clonogenic survival study indicated that Aurora-A(KD) cells and the wild-type cells transfected with Aurora-A siRNA or RelA/p65 siRNA were more radiosensitive than the wild-type cells. In both the wild-type and Aurora-A(KD) cells, radiation caused IkappaB kinase-mediated phosphorylation, degradation of IkappaBalpha and phosphorylation of RelA/p65. The nuclear translocation of RelA/p65 was also similar in the wild-type and Aurora-A(KD) cells. However, RelA/p65-DNA binding was markedly suppressed in Aurora-A(KD) cells compared to that in wild-type cells. It was concluded that Aurora-A enhances the binding of NF-kappaB to DNA, thereby increasing the gene transcription by NF-kappaB and decreasing the radiosensitivity of the cells.
Oh
Eun-Taex
ET
Department of Microbiology, Center for Advanced Medical Education by BK21 Project, College of Medicine, Inha University, Incheon 400-712, Republic of Korea.
Byun
Mi-Sun
MS
Lee
Hyemi
H
Park
Moon-Taek
MT
Jue
Dae-Myung
DM
Lee
Chang-Woo
CW
Lim
Byung Uk
BU
Park
Heon Joo
HJ
D064127:Aurora Kinases; D015153:Blotting, Western; D047369:Chromatin Immunoprecipitation; D004247:DNA / Q000378:metabolism*; D017931:DNA Primers; D024202:Electrophoretic Mobility Shift Assay; D055785:Gene Knockdown Techniques; D006367:HeLa Cells; D006801:Humans; D008856:Microscopy, Fluorescence; D016328:NF-kappa B / Q000378:metabolism*; D010766:Phosphorylation; D016133:Polymerase Chain Reaction; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering; D011836:Radiation Tolerance
D017931:DNA Primers; D016328:NF-kappa B; D034741:RNA, Small Interfering; D004247:DNA; D064127:Aurora Kinases; D017346:Protein Serine-Threonine Kinases