ABSTRACT
Objective:To investigate the expression of circ_0063865 in esophageal squamous cell carcinoma(ESCC)tissues and cells and its effect on the biological properties of the cells.Methods:The loop structure and stability of circ_0063865 were identified by Sanger sequencing, back-to-back primer validation and the ribonuclease R(Rnase R)tolerance assay.The expression of circ_0063865 was detected by RNA fluorescence in situ hybridization in an ESCC tissue microarray and its clinical relevance was analyzed.The expression levels of circ_0063865 in a normal esophageal epithelial cell line and ESCC cell lines were measured by real-time quantitative polymerase chain reaction(RT-qPCR). Cell counting Kit-8, the colony formation assay, the scratch assay, the transwell invasion assay and flow cytometry were used to detect the effects of circ_0063865 on cell proliferation, migration, invasion abilities and apoptosis, respectively.Results:The loop formation of circ_0063865 was verified by Sanger sequencing, back-to-back primer and Rnase R tolerance assays.The results of RNA fluorescence in situ hybridization showed that the mean fluorescence intensity of circ_0063865 expressed in ESCC tissues was significantly higher than in its paired paracancerous normal tissues( t=2.267, P<0.05). The expression of circ_0063865 was significantly associated with lymph node metastasis( χ2=4.356, P<0.05). The average overall survival time of patients with high circ_0063865 expression ESCC was lower than that of patients with low circ_0063865 expression ESCC.RT-qPCR results demonstrated that, compared with HEEC, circ_0063865 expression was elevated in ESCC cell lines( F=18.413, P<0.05). In addition, after circ_0063865 knockdown, the proliferation, migration and invasion abilities of KYSE-30 and KYSE-150 cells were significantly decreased, and the level of apoptosis was significantly increased(both P<0.05). Conclusions:The expression of circ_0063865 in ESCC is high, and changes in its expression are significantly correlated with lymph node metastasis.Additionally, circ_0063865 can promote the proliferation, migration and invasion of ESCC cells.