THAP8基因可被HIF-1α上调并促进肺癌细胞活力、克隆形成和侵袭

THAP8 is Upregulated by HIF-1α and Promotes Viability, Colony Formation and Invasion of Lung Cancer Cells

死亡相关蛋白(Thanatos-associated proteins,THAP)家族的许多成员已被证实与细胞增殖、凋亡和癌症密切相关,而THAP8的功能尚不清楚。为了探究THAP8在癌症中的表达,对TCGA和Oncomine数据库进行了分析,发现THAP8 m RNA在肺癌组织的表达显著高于癌旁正常组织;接着采用荧光定量PCR技术分析了22对肺癌和癌旁正常组织中THAP8的表达差异,结果与数据库分析一致。为了探讨THAP8在肺癌组织中高表达的原因,用JASPAR软件预测THAP8启动子上的转录因子结合位点,发现THAP8基因启动子区含有4个缺氧诱导元件。荧光素酶活性分析实验证明,缺氧诱导因子-1α(hypoxia-inducible factor-1α,HIF-1α)可以结合到THAP8启动子上的缺氧诱导元件并促进THAP8基因的转录。在CoCl_(2)诱导的缺氧模型中,随着CoCl_(2)浓度的增加,HIF-1α和THAP8蛋白的表达水平升高。此外,在Beas-2B细胞中,过表达HIF-1α可以促进THAP8的表达。为了进一步研究THAP8在肺癌细胞中的功能,用慢病毒介导的shRNA敲低THAP8基因,分析THAP8基因沉默对肺癌细胞生物学行为的影响。结果表明:在H460和H1437肺癌细胞中,敲低THAP8基因可显著降低细胞的活力、克隆形成和侵袭能力。这些结果说明:THAP8可以受缺氧诱导,并促进肺癌细胞的活力、克隆形成和侵袭,是一个新的癌基因。

Many members of the Thanatos-associated proteins(THAP)family have been proved to be closely related to cell proliferation,apoptosis and cancer,but the function of THAP8 is still unclear.In order to investigate the expression of THAP8 in cancer,the TCGA and Oncomine databases were analyzed and it was found that the expression of THAP8 mRNA in lung cancer tissues was significantly higher than that in normal tissues adjacent to lung cancer.Real-time quantitative PCR was then performed to analyze differential expressions of THAP8 in 22 pairs of lung cancer and adjacent non-cancerous tissues,and the result was consistent with that of database analysis.To explore the reason for THAP8 overexpression in cancer tissues,JASPAR software was used to predict the transcription factor binding sites within the THAP8 promoter,and four hypoxia response elements(HREs)were identified.The luciferase reporter assay demonstrated that the hypoxia-inducible factor-1α(HIF-1α)can bind to the HREs and promote the transcription of the THAP8 gene.In the CoCl_(2)-induced hypoxia model,with increasing CoCl_(2) concentration,expression levels of HIF-1αand THAP8 proteins increased.Overexpression of HIF-1αin Beas-2B cells promoted THAP8 expression.In order to study the role of THAP8 in lung cancer cells,lentivirus-mediated shRNA was used to inhibit the expression THAP8 gene,and the effects of THAP8 knockdown on the biological behavior of lung cancer cells were analyzed.The results showed that knockdown of THAP8 gene in both H460 and H1437 cells significantly decreased cell viability,colony formation and invasion.These results indicate that THAP8 can be induced by hypoxia,promoting the viability,colony formation and invasion of lung cancer cells,and proves a novel oncogene.