lncRNA KCNQ1OT1 reverses the effect of sevoflurane on hepatocellular carcinoma progression via regulating the miR-29a-3p/CBX3 axis

Sevoflurane (SEVO) is widely applied as an anesthetic, which exerts antitumor capacity in various cancers, including hepatocellular carcinoma (HCC). Previous studies indicated that long non-coding RNA KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1) was upregulated, while microRNA-29a-3p (miR-29a-3p) was downregulated in HCC. Thus, we aimed to explore the roles of KCNQ1OT1 and miR-29a-3p in HCC cells exposed to SEVO. Cell proliferation, apoptosis, migration, and invasion were assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometry, and transwell assays, respectively. The levels of genes were determined by quantitative real-time polymerase chain reaction (qRT-PCR) or western blot. Furthermore, the interaction between miR-29a-3p and KCNQ1OT1 or chromebox protein homolog 3 (CBX3) was predicted by Starbase or Targetscan, and then confirmed by dual-luciferase reporter assay. We found that the levels of KCNQ1OT1 and CBX3 were decreased, while miR-29a-3p was increased in SEVO-treated HCC cells. KCNQ1OT1 overexpression weakened the inhibitory effects of SEVO on HCC cell proliferation, apoptosis, migration, and invasion. Interestingly, KCNQ1OT1 bound to miR-29a-3p, and miR-29a-3p targeted CBX3. KCNQ1OT1 upregulated CBX3 level by repressing miR-29a-3p expression. Furthermore, KCNQ1OT1 exerted tumor promotion in HCC cells via suppressing miR-29a-3p to regulate CBX3 expression. Collectively, our findings demonstrated that KCNQ1OT1 regulated the antitumor effects of SEVO on HCC cells through modulating the miR-29a-3p/CBX3 axis, providing a theoretical basis for the treatment of HCC.

七氟醚（Sevoflurane，SEVO）作为临床常用吸入性麻醉剂，已被证实可在多种恶性肿瘤中发挥抗肿瘤活性，其中包括肝细胞癌（hepatocellular carcinoma，HCC）。既往研究表明，长链非编码RNA KCNQ1反向链/反义转录本1（KCNQ1OT1）在肝细胞癌中呈高表达，而微小RNA-29a-3p（microRNA-29a-3p，miR-29a-3p）则呈低表达。据此，本研究旨在探讨KCNQ1OT1与miR-29a-3p在经SEVO处理的肝细胞癌细胞中的调控作用。本研究分别采用3-(4,5-二甲基噻唑-2-基)-2,5-二苯基溴化四氮唑蓝（MTT）法、流式细胞术及Transwell实验检测肝细胞癌细胞的增殖、凋亡、迁移与侵袭能力；通过实时定量聚合酶链反应（qRT-PCR）或蛋白质印迹（western blot）检测相关基因的表达水平。此外，通过Starbase数据库与Targetscan数据库预测miR-29a-3p与KCNQ1OT1或染色盒蛋白同源物3（chromebox protein homolog 3，CBX3）的靶向结合关系，并利用双荧光素酶报告基因实验验证上述相互作用。实验结果显示，经SEVO处理的肝细胞癌细胞中，KCNQ1OT1与CBX3的表达水平显著下调，而miR-29a-3p的表达水平显著上调。过表达KCNQ1OT1可削弱SEVO对肝细胞癌细胞增殖、凋亡、迁移及侵袭的抑制作用。机制研究发现，KCNQ1OT1可直接结合miR-29a-3p，而miR-29a-3p可靶向调控CBX3的表达；KCNQ1OT1通过抑制miR-29a-3p的表达，正向上调CBX3的蛋白水平。进一步研究证实，KCNQ1OT1可通过靶向抑制miR-29a-3p、调控CBX3的表达，在肝细胞癌细胞中发挥促肿瘤作用。综上，本研究结果表明，KCNQ1OT1可通过调控miR-29a-3p/CBX3轴，参与SEVO对肝细胞癌细胞的抗肿瘤作用，为肝细胞癌的临床治疗提供了新的理论依据。