LncRNA TUSC7 Inhibits the Proliferation and Invasion of Gastric Cancer Cells by Regulating the miR-130b-5p/PCDH9 Axis

Background: Increasing evidence suggests that long non-coding RNAs (lncRNAs) play an important regulatory role in the physiopathology of tumors. Previous studies have shown that Tumor suppressor candidate 7 (TUSC7) is a suppressor lncRNA in a variety of tumors. However, the role of TUSC7 in gastric cancer (GC) remains unclear. The aim of this study is to evaluate the effect and mechanisms of TUSC7 on GC. Methods: Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression of TUSC7, miR-130b-5p, and Protocadherin-9 (PCDH9) in GC tissues and cells. Western blot was used to detect protein expression levels of PCDH9. pcDNA3.1-TUSC7 (pc-TUSC7), miR-130b-5p mimics, miR-130b-5p inhibitors and pc-TUSC7 + si-PCDH9 were transfected to SGC-7901 cells using Lipofectamine (TM) 2000. Cell proliferation and invasion were assessed using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, colony formation assay and transwell assay. Relationship of TUSC7 with miR-130b-5p or miR-130b-5p with PCDH9 were determined using dual-luciferase reporter assays. Results: TUSC7 was down-regulated in GC tissues and cell lines. Over-expression of TUSC7 suppresses GC cell proliferation and invasion. The double luciferase reporter gene experiment showed that TUSC7 can target miR-130b-5p in GC and interact negatively with miR-130b-5p. It was observed that PCDH9 was a target gene of miR-130b-5p. In addition, rescue experiments have shown that TUSC7 can up-regulate PCDH9 to slow the progress of GC by targeting miR-130b-5p. Conclusions: TUSC7 inhibits the proliferation and invasion of GC cells through the miR-130b-5p/PCDH9 axis.