ebv-circRPMS1 promotes the progression of EBV-associated gastric carcinoma via Sam68-dependent activation of METTL3.

Epstein-Barr virus (EBV) is a tumor virus that is associated with a variety of neoplasms, including EBV-associated gastric carcinoma (EBVaGC). Recently, EBV was reported to generate various circular RNAs (circRNAs). CircRNAs are important regulators of tumorigenesis by modulating the malignant behaviors of tumor cells. However, to date, the functions of ebv-circRNAs in EBVaGC remain poorly understood. In the present study, we observed high ebv-circRPMS1 expression in EBVaGC and showed that ebv-circRPMS1 promoted the proliferation, migration, and invasion and inhibited the apoptosis of EBVaGC cells. In addition, METTL3 was upregulated in GC cells overexpressing ebv-circRPMS1. Mechanistically, ebv-circRPMS1 bound to Sam68 to facilitate its physical interaction with the METTL3 promotor, resulting in the transactivation of METTL3 and cancer progression. In clinical EBVaGC samples, ebv-circRPMS1 was associated with distant metastasis and a poor prognosis. Based on these findings, ebv-circRPMS1 contributed to EBVaGC progression by recruiting Sam68 to the METTL3 promoter to induce METTL3 expression. ebv-circRPMS1, Sam68, and METTL3 might serve as therapeutic targets for EBVaGC.

EBV-Induced CXCL8 Upregulation Promotes Vasculogenic Mimicry in Gastric Carcinoma via NF-κB Signaling.

Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC) is a distinct entity with a conspicuous tumor microenvironment compared with EBV-negative gastric carcinoma. However, the exact role of EBV in gastric carcinogenesis remains elusive. In the present study, we found that EBV upregulated CXCL8 expression, and CXCL8 significantly promoted vasculogenic mimicry (VM) formation of gastric carcinoma (GC) cells. In accordance with these observations, overexpression of CXCL8 increased cell proliferation and migration of AGS and BGC823 cells, while knockdown of CXCL8 with siRNA inhibited cell proliferation and migration of AGS-EBV cells. In addition, activation of NF-κB signaling was involved in VM formation induced by CXCL8, which was blocked by NF-κB inhibitors BAY 11-7082 and BMS345541. Furthermore, EBV-encoded lncRNA RPMS1 activated the NF-κB signaling cascade, which is responsible for EBV-induced VM formation. Both xenografts and clinical samples of EBVaGC exhibit VM histologically, which are correlated with CXCL8 overexpression. Finally, CXCL8 is positively correlated with overall survival in GC patients. In conclusion, EBV-upregulated CXCL8 expression promotes VM formation in GC via NF-κB signaling, and CXCL8 might serve as a novel anti-tumor target for EBVaGC.

Fundus optic disc localization and segmentation method based on phase congruency.

It has been demonstrated that shape, area and depth of the optic disc are relevant indices of diabetic retinopathy. In this paper, we present a new fundus optic disc localization and segmentation method based on phase congruency (PC). Firstly, in order to highlight the optic disc, channel images with the highest contrast between optic disc and background are selected in LAB, YUV, YIQ and HSV spaces respectively. Secondly, with the use of PC, features of four selected channel images can be extracted. Multiplication operation is then used to enhance PC detection results. Thirdly, window scanning and gray accumulating are utilized to locate the optic disc. Finally, iterative OTSU automatic threshold segmentation and Hough transform are performed on location images, before the final optic disc segmentation result can be obtained. The experimental results showed that the proposed method can effectively and accurately perform optic disc location and segmentation.