Upregulation of circular SMAD7 inhibits tumorigenesis of gastric cancer by reversing epithelial-to-mesenchymal transition

X.-Y. Zhang, Y.-Y. Xu, W.-Y. Chen

Department of Gastrointestinal and Colorectal Surgery, China-Japan Union Hospital of Jilin University, Changchun, China. 776726739@qq.com

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• Oncology

OBJECTIVE: Gastric cancer (GC) is one of the most ordinary malignant tumors. Recent studies have revealed that circular RNAs (circRNAs) play an important role in the progression of tumorigenesis. In this research, circ-SMAD7 was selected to identify how it functions in the progression of GC.

PATIENTS AND METHODS: Circ-SMAD7 expression in paired GC patients’ tissue samples and cell lines was detected by Real Time-quantitative Polymerase Chain Reaction (RT-qPCR). The role of circ-SMAD7 in the metastasis of GC was detected through wound healing assay and transwell assay. Western blot assay and RT-qPCR were used to discover the function of circ-SMAD7 in epithelial-to-mesenchymal transition (EMT) process. Furthermore, tumor metastasis assay was also performed in vivo.

RESULTS: In this study, RT-qPCR results showed that circ-SMAD7 expression was significantly lower in GC tissues compared to that in adjacent ones. Cell migration and invasion of GC were inhibited via upregulation of circ-SMAD7. Moreover, the results of further experiments revealed that the EMT-related proteins were regulated via upregulation of circ-SMAD7 in GC. Furthermore, tumor metastasis of GC was inhibited via upregulation of circ-SMAD7 in nude mice.

CONCLUSIONS: These results indicate that upregulation of circ-SMAD7 inhibits GC cell migration and invasion via reversing the EMT process.

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