Xu Ying, Wang Chunliang, Lu Xingang, Qi Ruihua, Wang Xiao, Zhao Jinrong
Department of Anorectal, The First People's Hospital of Fuyang District Hangzhou, Zhejiang Province, China.
Am J Transl Res. 2021 Sep 15;13(9):10038-10055. eCollection 2021.
Colorectal cancer (CRC) is a malignant tumor commonly found in the digestive tract. This study aimed to explore the effect of circRNA_002178 as a competing endogenous RNA in the development of CRC by regulating the miR-542-3p/cAMP response element binding protein 1 (CREB1) axis and its molecular mechanism.
The relative expressions of circ_002178, miR-542-3p, and CREB1 in patients' cell lines and CRC tissues were measured using Western blot and qRT-PCR. The localization and expression of circ_002178 were determined using fluorescence in situ hybridization and nucleocytoplasmic separation tests. The targeting relationships among circ_002178, miR-542-3p, and CREB1 were validated using RNA immunoprecipitation and dual luciferase reporter assays. The cells' proliferation, invasion, and colony forming ability were tested using CCK8, Transwell, and Clone formation assays, respectively. The cellular glucose consumption, lactification, and adenosine triphosphate (ATP) production were measured using glucose uptake colorimetric assay kits, lactate colorimetric assay kits and ATP assay kits, respectively.
The circ_002178 and CREB1 expressions were up-regulated in the CRC cells and tissues, and the miR-542-3p expression was down-regulated (all P<0.05). The circ_002178 knockdown inhibited the proliferation, invasion, colony formation, and glycolysis of the CRC cells , but the overexpression of circ_002178 induced the opposite result (both P<0.05). Our molecular mechanism study revealed that circ_002178, as the molecular sponge of miR-542-3p, promotes CREB1 expression. The downregulation of miR-542-3p or the overexpression of CREB1 is able to partly weaken the inhibition of CRC cells through the circ_002178 knockdown.
circ_002178 promotes the invasion, proliferation, colony formation, and glycolysis of CRC cells by regulating the miR-542-3p/CREB1 axis, thus driving the development of CRC.
结直肠癌（CRC）是消化道常见的恶性肿瘤。本研究旨在通过调控miR-542-3p/环磷酸腺苷反应元件结合蛋白1（CREB1）轴，探讨环状RNA_002178作为竞争性内源RNA在结直肠癌发生发展中的作用及其分子机制。
采用蛋白质免疫印迹法和实时荧光定量PCR检测患者细胞系及结直肠癌组织中circ_002178、miR-542-3p和CREB1的相对表达水平。利用荧光原位杂交和核质分离试验确定circ_002178的定位和表达情况。采用RNA免疫沉淀和双荧光素酶报告基因检测验证circ_002178、miR-542-3p和CREB1之间的靶向关系。分别采用CCK8、Transwell和克隆形成试验检测细胞的增殖、侵袭和克隆形成能力。分别使用葡萄糖摄取比色法试剂盒、乳酸比色法试剂盒和ATP检测试剂盒测定细胞的葡萄糖消耗、乳酸生成和三磷酸腺苷（ATP）产生量。
结直肠癌细胞和组织中circ_002178和CREB1表达上调，miR-542-3p表达下调（均P<0.05）。敲低circ_002178可抑制结直肠癌细胞的增殖、侵袭、克隆形成和糖酵解，而过表达circ_002178则产生相反结果（均P<0.05）。我们的分子机制研究表明，circ_002178作为miR-542-3p的分子海绵，促进CREB1表达。下调miR-542-3p或过表达CREB1能够部分削弱敲低circ_002178对结直肠癌细胞的抑制作用。
circ_002178通过调控miR-542-3p/CREB1轴促进结直肠癌细胞的侵袭、增殖、克隆形成和糖酵解，从而推动结直肠癌的发生发展。
