CIRCULAR RNA BTG2 INHIBITS THE PROLIFERATION AND METASTASIS OF ESOPHAGEAL SQUAMOUS CARCINOMA VIA MIR-92B-3P

Wei Wang^{1, 2}, Ran Yu^{1 2}, Yao Xiao², Xiaolu Lin⁴, Suqin Zhou¹, Jian Song^{1, 3}, Haoyu Chen¹, Wanpeng Wang^1*, Juan Pu^1,3*

¹Department of Central Laboratory - ²Department of Clinical Laboratory - ³Department of Radiation Oncology, Lianshui County People’s Hospital, Kangda College of Nanjing Medical University, Huai'an 223400, China - ⁴Department of Digestive Endoscopy, Fujian Province Hospital, Fujian Medical University, Fuzhou 350001, China

Introduction: To explore the expression of CircBTG2 in esophageal squamous cancer (ESCC) and investigate the effect of CircBTG2 on the proliferation and invasion of ESCC. 

Materials and methods: The medical records and pathological tissue of 33 ESCC patients treated in Lianshui County People's Hospital from January 2019 to April 2020 were collected and analyzed. The expression of CircBTG2 in normal esophageal mucosa and ESCC was detected by qRT-PCR. CircBTG2 overexpression plasmid was transfected into KYSE150 cells, an ESCC cell line, then cell proliferation was detected by CCK-8. Wound healing analysis, Transwell chamber invasion assay and clone formation experiment were performed to detect the metastatic ability of KYSE150 cells. The Luciferase reporter assay was used to detect whether CircBTG2 sponge miR-92b-3p. The expression levels of Kruppel like factor 4 (KLF4) and desmocollin 2 (DSC2) were detected by Western blot.

Results: The expression level of CircBTG2 in ESCC (2.994±0.927) was significantly lower than that in normal esophageal mucosa (4.76±1.503). After transfection of CircBTG2 overexpression plasmid into ESCC cell line KYSE150, the proliferation of CircBTG2 overexpression KYSE150 cells was significantly inhibited at 72h and 96h compared with the untransfected cells (t=2.364, 5.199; P=0.046, 0.001). In addition, the lateral migration, vertical invasion and colony formation of CircBTG2 overexpression KYSE150 cells were markedly inhibited. The results of luciferase assay showed that the fluorescence intensity of KYSE150 cells was significantly reduced after co-transfection of CircBTG2 overexpressing plasmid and miR-92b-3p mimics, suggesting that CircBTG2 has the ability to sponge miR-92b-3p. The results of Western blot demonstrated that the expression of KLF4 and DSC2 significantly increased after CircBTG2 overexpression (t=5.335, 6.688; P=0.006, 0.003).

Conclusion: In ESCC, the expression of CircBTG2 was significantly decreased. CircBTG2 promoted the expression of KLF4 and DSC2 via sponging miR-92B-3p, thereby inhibiting the proliferation and metastasis of ESCC. Therefore, CircBTG2 has potential as a diagnostic marker and therapeutic target for ESCC.