Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
BMC Cancer. 2009 Dec 12;9:435. doi: 10.1186/1471-2407-9-435.
Overexpression of Aurora-A and mutant Ras (RasV12) together has been detected in human bladder cancer tissue. However, it is not clear whether this phenomenon is a general event or not. Although crosstalk between Aurora-A and Ras signaling pathways has been reported, the role of these two genes acting together in tumorigenesis remains unclear.
Real-time PCR and sequence analysis were utilized to identify Ha- and Ki-ras mutation (Gly -> Val). Immunohistochemistry staining was used to measure the level of Aurora-A expression in bladder and colon cancer specimens. To reveal the effect of overexpression of the above two genes on cellular responses, mouse NIH3T3 fibroblast derived cell lines over-expressing either RasV12 and wild-type Aurora-A (designated WT) or RasV12 and kinase-inactivated Aurora-A (KD) were established. MTT and focus formation assays were conducted to measure proliferation rate and focus formation capability of the cells. Small interfering RNA, pharmacological inhibitors and dominant negative genes were used to dissect the signaling pathways involved.
Overexpression of wild-type Aurora-A and mutation of RasV12 were detected in human bladder and colon cancer tissues. Wild-type Aurora-A induces focus formation and aggregation of the RasV12 transformants. Aurora-A activates Ral A and the phosphorylation of AKT as well as enhances the phosphorylation of MEK, ERK of WT cells. Finally, the Ras/MEK/ERK signaling pathway is responsible for Aurora-A induced aggregation of the RasV12 transformants.
Wild-type-Aurora-A enhances focus formation and aggregation of the RasV12 transformants and the latter occurs through modulating the Ras/MEK/ERK signaling pathway.
在人类膀胱癌组织中已检测到 Aurora-A 的过表达和突变型 Ras（RasV12）的共同表达。然而，这种现象是否是普遍现象尚不清楚。尽管已报道 Aurora-A 和 Ras 信号通路之间存在串扰，但这两个基因共同在肿瘤发生中的作用仍不清楚。
利用实时 PCR 和序列分析鉴定 Ha-和 Ki-ras 突变（Gly -> Val）。免疫组织化学染色用于测量膀胱癌和结肠癌标本中 Aurora-A 的表达水平。为了揭示上述两种基因过表达对细胞反应的影响，建立了表达 RasV12 和野生型 Aurora-A（命名为 WT）或 RasV12 和激酶失活型 Aurora-A（KD）的小鼠 NIH3T3 成纤维细胞衍生的细胞系。MTT 和焦点形成测定用于测量细胞的增殖率和焦点形成能力。使用小干扰 RNA、药理学抑制剂和显性负基因来剖析涉及的信号通路。
在人类膀胱癌和结肠癌组织中检测到过表达的野生型 Aurora-A 和突变型 RasV12。野生型 Aurora-A 诱导 RasV12 转化体的焦点形成和聚集。Aurora-A 激活 Ral A 和 AKT 的磷酸化，并增强 WT 细胞中 MEK、ERK 的磷酸化。最后，Ras/MEK/ERK 信号通路负责 Aurora-A 诱导的 RasV12 转化体的聚集。
野生型 Aurora-A 增强了 RasV12 转化体的焦点形成和聚集，后者通过调节 Ras/MEK/ERK 信号通路发生。
