Downregulated Long Noncoding RNA GAS5 Fails to Function as Decoy of CEBPB, Resulting in Increased GDF15 Expression and Rapid Ovarian Cancer Cell Proliferation
Downregulated Long Noncoding RNA GAS5 Fails to Function as Decoy of CEBPB, Resulting in Increased GDF15 Expression and Rapid Ovarian Cancer Cell Proliferation
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DOI：
10.1089/cbr.2019.2889
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发表时间：
2019-10-01
影响因子：
3.4
通讯作者：
Wang, Shan-feng
中科院分区：
文献类型：
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作者：
Guo, Lin-lin;Wang, Shan-feng
生长分化因子15 （GDF15）是转化生长因子（GDF）超家族的新成员，在卵巢癌（OV）中表达上调。GDF15表达上调与OV癌预后不良呈正相关。因此，阐明GDF15过表达的机制非常重要。方法与结果：利用PROMO和JASPAR预测软件寻找GDF15表达的转录因子。分析TCGA数据库的数据，发现长链非编码rna （lncrna）也在OV癌中异常表达，并与GDF15表达相关。转录因子CEBPB被预测为GDF15的重要调节因子，通过荧光素酶报告基因实验证实。而CEBPB在OV癌中的表达无明显变化。TCGA数据库数据显示，lncRNA GAS5在OV癌中下调，其表达与GDF15表达呈负相关。RPISeq显示GAS5对CEBPB具有高亲和力，并通过rna结合蛋白免疫沉淀实验证实了这一点。GAS5过表达增加其与CEBPB的结合，从而下调GDF15。GAS5过表达和GDF15敲低降低OV癌细胞活力，增加凋亡，而CEBPB过表达则相反。然而，GAS5和CEBPB同时过表达或CEBPB过表达并敲低GDF15对细胞活力和凋亡没有影响。结论：GAS5作为CEBPB的诱饵，阻断了CEBPB对GDF15的转录促进作用。
Introduction: Growth differentiation factor 15 (GDF15), a newly identified member of transforming growth factor (GDF) superfamily, is upregulated in ovarian (OV) cancer. Upregulated GDF15 positively correlates with poor prognosis of OV cancer. Thus, elucidation of the mechanism underlying GDF15 overexpression is important. Method and Results: PROMO and JASPAR prediction software were used to find transcription factors for GDF15 expression. Data from TCGA database were analyzed to find long noncoding RNAs (lncRNAs) that were also abnormally expressed in OV cancer and had associations with GDF15 expression. Transcription factor CEBPB was predicted as an important regulator of GDF15, confirmed by luciferase reporter assay. However, CEBPB expression was not significantly changed in OV cancer. Data from TCGA database showed that lncRNA GAS5 is downregulated in OV cancer and its expression is negatively correlated with GDF15 expression. RPISeq showed high affinity of GAS5 to CEBPB and this was confirmed by RNA-binding protein immunoprecipitation assay. GAS5 overexpression increased its binding to CEBPB and consequently downregulated GDF15. GAS5 overexpression and GDF15 knockdown decreased viability and increased apoptosis of OV cancer cells, but CEBPB overexpression had opposite effects. However, simultaneous GAS5 and CEBPB overexpression or CEBPB overexpression together with GDF15 knockdown had no effect on cell viability and apoptosis. Conclusion: GAS5 functions as decoy of CEBPB, blocking transcription-promoting effect of CEBPB on GDF15.