目的：探讨hsa_circ_0140180 在食管鳞状细胞癌（ESCC）细胞中的表达水平及对其细胞恶性生物学行为的影响与分子机制。方法：收集2018 年11月至2019 年3月间在南充市中心医院胸心外科手术切除的6对ESCC 组织和对应癌旁组织并进行全转录组测序，筛选出在ESCC 组织中低表达的hsa_circ_0140180；建立过表达hsa_circ_0140180 的TE-1 和KYSE30 细胞，qPCR法检测hsa_circ_0140180 在人正常食管上皮细胞、ESCC细胞中的表达，以及过表达hsa_circ_0140180 后TE-1和KYSE30 细胞中miR-1287-5p的表达；CCK-8法和FCM检测过表达hsa_circ_0140180 对TE-1和KYSE30细胞增殖和周期的影响；划痕实验和Transwell 实验检测过表达hsa_circ_0140180 对TE-1和KYSE30 细胞迁移和侵袭能力的影响，双荧光素酶报告实验验证hsa_circ_0140180 与miR-1287-5p 的靶向关系。WB 法检测过表达hsa_circ_0140180 对TE-1 和KYSE30 细胞中EMT 相关蛋白的表达及PI3K-Akt 通路的磷酸化水平的影响。结果：转录组测序和qPCR 结果显示，hsa_circ_0140180 在ESCC组织和细胞中呈低表达（P<0.05 或P<0.01），并确认其闭合环状分子特征且定位于细胞质。过表达hsa_circ_0140180 能明显抑制ESCC 细胞的迁移及侵袭能力（P<0.05），但不影响其增殖和周期。双荧光素酶报告基因实验证实hsa_circ_0140180 靶向结合miR-1287-5并负调控其表达（P<0.01）。过表达hsa_circ_0140180 能显著上调TE-1和KYSE30细胞中E-cadherin 的表达（（P<0.05），而显著下调Snail 的表达（P<0.05）和PI3K-Akt 通路的磷酸化水平（P<0.01 或P<0.001）。结论：hsa_circ_0140180 在ESCC细胞及组织中呈低表达，其可能通过调控miR-1287-5p表达来降低PI3K-Akt通路的磷酸化水平和抑制EMT进程，从而影响ESCC细胞的迁移及侵袭能力。

Objective: To investigate the expression level of hsa_circ_0140180 in esophageal squamous cell carcinoma (ESCC) cells,as well as its effect on malignant biological behavior of ESCC cells and the possible molecular mechanisms. Methods: Six pairs of ESCC tissues and corresponding paracarcinoma tissues resected at the Department of Thoracic Surgery, Central Hospital of Nanchong City between November 2018 and March 2019 were collected for whole-transcriptome sequencing, and hsa_circ_0140180 at a low expression in ESCC tissues was screened out. The TE-1 and KYSE30 cell lines overexpressing hsa_circ_0140180 were established.qPCR was used to detect the expression of hsa_circ_0140180 in human normal esophageal epithelial cells and ESCC cells, as well as the expression of miR-1287-5p in TE-1 and KYSE30 cells overexpressing hsa_circ_0140180. CCK-8 and FCM were used to detect theeffect of hsa_circ_0140180 overexpression on the proliferation and cell cycle of TE-1 and KYSE30 cells. Scratch assay and Transwellassay were used to assess the effects of hsa_circ_0140180 overexpression on migration and invasion of TE-1 and KYSE30 cells. Dual-luciferase reporter assay was used to confirm the targeting relationship between hsa_circ_0140180 and miR-1287-5p. WB assay was used to detect the expression of EMT-related proteins and the phosphorylation level of the PI3K-Akt pathway in TE-1 and KYSE30 cells after hsa_circ_0140180 overexpression. Results: Transcriptome sequencing and qPCR results showed that hsa_circ_0140180 was lowly expressed in ESCC tissues and cells (P<0.05 or P<0.01) and confirmed its closed-loop molecular signature and localization in the cytoplasm. Overexpression of hsa_circ_0140180 could significantly inhibit the migration and invasion of ESCC cells (all P<0.05) but had no significant effect on the proliferation and cell cycle. The results of dual-luciferase reporter gene assay demonstrated that hsa_circ_0140180 targets miR-1287-5p and negatively regulates its expression (P<0.001). Overexpression of hsa_circ_0140180 could significantly increase the expression of E-cadherin and decrease the expression of Snail (both P<0.05) and the phosphorylation level of the PI3K-Akt pathway (P<0.01, P<0.001) in TE-1 and KYSE30 cells. Conclusion: hsa_circ_0140180 is lowly expressed in ESCC cells and tissues; it reduces the phosphorylation levels of PI3K-Akt pathway and suppresses EMT process possibly through regulation of miR-1287-5p expression, thus affecting the migration and invasion abilities of ESCC cells.

国家自然科学基金（No. 82203851）；南充市市校科技战略合作专项（No. 20SXQT0328、No. 22SXQT0336）