Long noncoding RNA lnc-LEMGC combines with DNA-PKcs to suppress gastric cancer metastasis

Long non-coding RNAs (lncRNAs) play important roles in cancer development and progression; however, their contributions to gastric cancer metastasis remain largely unknown. By lncRNA microarray screening, our study showed that 10 lncRNAs are dysregulated in gastric cancer tissues with or without lymph node metastasis, of which lnc-LEMGC ranks as one of the most significantly downregulated lncRNAs. Lnc-LEMGC inhibited cell migration and invasion both in vitro and in vivo, by combining with protein DNA-PKcs. Importantly, nucleotides 1,300–1,800 of lnc-LEMGC prevented DNA-PKcs phosphorylation of serine 2056 and partially abrogated the effects of downstream effectors, transforming growth factor alpha, EGFR, Src kinase, paxillin, and focal adhesion kinase, in the epidermal growth factor receptor (EGFR) pathway. The results of this study extend our knowledge of lncRNA’s molecular mechanisms, in which lnc-LEMGC functions by directly suppressing the phosphorylation of its combined protein DNA-PKcs and inactivating the DNA-PKcs downstream EGFR signaling. We transfected GC SGC7901 cells with lnc-LEMGC vector or NC for 48h. We then used the Whole Human Genome Oligo Microarray Assay (KangChen Bio-Tech, Shanghai, China) to analyze differential gene expression between the lnc-LEMGC-overexpression SGC7901 cells and negative control cells.