Identification of downstream target genes of transcription factor ZEB1, lncRNA FGD5-AS1 and miR-34a-5p in gastric cancer

As one of the most abundant lncRNAs in cells, the biological function of lncRNA FGD5-AS1 remains largely unclear in cancers, especially in gastric cancer (GC). In addition, the reason for such high levels of FGD5-AS1 in cells remains unknown. In this study, FGD5-AS1 was proved to be a ZEB1-related lncRNA which was overexpressed and predicted poor prognosis in GC. Knockdown of FGD5-AS1 decreased GC proliferation in vitro and in vivo. Overall design: To reveal the molecular mechanism by which FGD5-AS1 drives gastric cancer progression, we established GC cell lines knocked down the expression of FGD5-AS1. The transcriptome sequencing studies were performed by deep sequencing. Exploration of downstream target genes of transcription factor ZEB1 in gastric cancer cell lines. The GC cell lines were transfected with miR-34a-5p mimics and negative control siRNAs. After effective transcrection, the genes downregulated by miR-34a-5p were screened by RNA sequencing.

长链非编码RNA（long non-coding RNA, lncRNA）FGD5-AS1是细胞内丰度最高的lncRNA之一，但其生物学功能在癌症领域，尤其是胃癌（gastric cancer, GC）中仍未得到充分阐明。此外，细胞内FGD5-AS1高表达的具体原因也尚不明确。本研究证实，FGD5-AS1是一种与转录因子ZEB1相关的lncRNA，在胃癌组织中呈高表达状态，且可提示患者不良预后。敲低FGD5-AS1可在体内外抑制胃癌细胞的增殖。
整体实验设计：为揭示FGD5-AS1驱动胃癌进展的分子机制，我们构建了FGD5-AS1敲低的胃癌细胞系。通过深度测序开展转录组测序研究，并探索胃癌细胞系中转录因子ZEB1的下游靶基因。此外，将胃癌细胞系转染miR-34a-5p模拟物与阴性对照小干扰RNA（small interfering RNA, siRNA），在成功转染后，通过RNA测序筛选出受miR-34a-5p下调的基因。