TCTP promotes glioma cell proliferation in vitro and in vivo via enhanced β-catenin/TCF-4 transcription
TCTP promotes glioma cell proliferation in vitro and in vivo via enhanced β-catenin/TCF-4 transcription
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DOI：
10.1093/neuonc/not194
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发表时间：
2014-02-01
期刊：
影响因子：
15.9
通讯作者：
Li, Keshen
中科院分区：
文献类型：
--
作者：
Gu, Xuefeng;Yao, Lifen;Li, Keshen
背景肿瘤抑制蛋白（TCTP）是一种多功能蛋白，在免疫应答、细胞增殖、致瘤性和细胞凋亡中发挥重要作用。在此，我们研究了TCTP在胶质瘤患者生存中的临床价值，并探讨了TCTP在胶质瘤发展中的功能作用和机制。通过免疫组织化学染色、免疫印迹和定量实时PCR（qRT-PCR）测定TCTP表达。使用短发夹（sh）RNA沉默TCTP或TCF-4表达。采用MTT法、BrdU法和集落形成法检测体外细胞增殖情况，采用异种移植模型检测体内肿瘤生长情况。使用免疫共沉淀（co-IP）测定检测TCTP/TCF-4/β-连环蛋白缔合。使用TOPflash/FOPflash报告基因测定法检测TCF-4转录活性。Western blot检测Wnt/β-catenin靶基因的表达。高级别胶质瘤中TCTP蛋白水平显著高于低级别胶质瘤和正常脑组织。重要的是，TCTP的表达与较差的总生存期和无病生存期显著相关，并且TCTP还降低了胶质瘤患者放疗和替莫唑胺（RT-TMZ）治疗后的生存率。TCTP的异位表达增强胶质瘤细胞的增殖在体外和体内，而TCTP的敲低抑制这种效果。类似地，TCTP的过表达增加了β-连环蛋白与TCF-4的结合、TOP flash报告基因转录活性以及Wnt/β-连环蛋白信号传导靶基因（包括c-Myc和细胞周期蛋白D1）的表达;值得注意的是，TCTP的敲低降低了这些作用。利用shRNA敲低TCF-4基因，可抑制TCTP过表达诱导的细胞增殖。TCTP与胶质瘤患者的存活率降低相关，并通过增强的Wnt/β-连环蛋白信号传导诱导胶质瘤肿瘤生长。
Background. The translationally controlled tumor protein (TCTP) is a multifunctional protein that plays important roles in immune responses, cell proliferation, tumorigenicity and cell apoptosis. Here, we examined the clinical value of TCTP in glioma patient survival and investigated the functional roles and mechanism of TCTP in glioma development.Methods. TCTP expression was determined through immunohistochemical staining, immunoblotting, and quantitative real-time PCR (qRT-PCR). TCTP or TCF-4 expression was silenced using short hairpin (sh) RNA. In vitro cell proliferation was detected using MTT, BrdU and colony formation assays, and in vivo tumor growth was performed using the xenograft model. TCTP/TCF-4/beta-catenin association was detected using a co-immunoprecipitation (co-IP) assay. TCF-4 transcription activity was detected using a TOPflash/FOPflash report gene assay. Wnt/beta-catenin-targeted gene expression was detected through Western blotting.Results. TCTP protein levels were significantly elevated in high-grade gliomas compared with low-grade gliomas and normal brain tissues. Importantly, the expression of TCTP was significantly associated with poorer overall survival and disease-free survival, and TCTP also reduced the survival rate after treatment with radiotherapy and temozolomide (RT-TMZ) for glioma patients. The ectopic expression of TCTP enhanced glioma cell proliferation both in vitro and in vivo, whereas the knockdown of TCTP inhibited this effect. Similarly, the overexpression of TCTP increased beta-catenin binding to TCF-4, TOP flash report gene transcription activity, and the expression of Wnt/beta-catenin signaling target genes including c-Myc and cyclin D1; notably, the knockdown of TCTP reduced these effects. The knockdown of TCF-4 using shRNA rescued the enhanced cell proliferation induced by the overexpression of TCTP.Conclusion. TCTP is associated with reduced survival of glioma patients and induces glioma tumor growth through enhanced Wnt/beta-catenin signaling.