The upregulation of circFNDC3B aggravates the recurrence after endoscopic submucosal dissection (ESD) in early gastric cancer (EGC) patients

It has been reported that the expression of CD44 variant 9 could be utilized as a predictive marker for the recurrence in early gastric cancer (EGC) after endoscopic submucosal dissection (ESD). And circFNDC3B was proved to increase the migration and invasion of gastric cancer (GC) cells. In this study, we recruited 96 EGC patients after ESD treatment and grouped them into High circFNDC3B expression group (High expression group) and Low circFNDC3B expression group (Low expression group). Accordingly, we found that the recurrence-free rate in the High expression group was lower than that in the Low expression group. In the High expression group, the relative expression of miR-942 and miR-510 was both suppressed while the relative expression of CDH1 mRNA and CD44 mRNA/protein was increased compared with those in the Low expression group. CircFNDC3B was found to target miR-942 and miR-510 and suppress their expressions respectively. Moreover, miR-942 was found to target CD44 mRNA while miR-510 was found to target CDH1 mRNA. The overexpression of circFNDC3B led to the down-regulation of miR-942 and miR-510, which accordingly resulted in the up-regulation of CD44 and CDH1 in MKN28 cells. Moreover, we found H. pylori infection could promote the expression of circFNDC3B, which also resulted in up-regulated CD44 and CDH1 mRNA level in rTip-α cultivated MKN28 cells. In summary, our study demonstrated that a higher level of circFNDC3B could lead to the increased expression of CD44 and CDH1 via modulating the signaling pathways of miR-942/CD44 and miR-510/CDH1 in EGC patients. And the up-regulation of CD44 and CDH1 would accordingly result in a higher recurrence rate of EGC patients treated by ESD.