Chen Bing, Liu Yuling, Jin Xuewen, Lu Weiliang, Liu Jingjing, Xia Zijing, Yuan Qiong, Zhao Xia, Xu Ningzhi, Liang Shufang
State Key Laboratory of Biotherapy/Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, No,17, the third section of Renmin South Road, Chengdu 610041, P, R, China.
BMC Cancer. 2014 Jun 16;14:443. doi: 10.1186/1471-2407-14-443.
Reprogramming energy metabolism has been an emerging hallmark of cancer cells. MicroRNAs play important roles in glucose metabolism.
The targets of microRNA-26a (miR-26a) were predicted by bioinformatics tools. The efficacy of miR-26a binding the 3'-untranslated region (UTR) of pyruvate dehydrogenase protein X component (PDHX) mRNA was evaluated using a dual-luciferase reporter assay. The PDHX expression at the mRNA and protein level in several colon cancer cell lines was quantified with real-time PCR and Western blot analysis respectively. The effects of miR-26a on glucose metabolism were determined by detecting the content of glucose consumption, production of lactate, pyruvate, and acetyl-coenzyme A.
The expression of miR-26a is inversely associated with the level of its targeting protein PDHX in several colon cancer cell lines with different malignancy potentials. MiR-26a inhibits PDHX expression by direct targeting the 3'-UTR of PDHX mRNA. The glucose consumption and lactate concentration were both greatly increased in colon cancer cells than the normal colon mucosal epithelia under physiological conditions. The overexpression of miR-26a in HCT116 cells efficiently improved the accumulation of pyruvate and decreased the production of acetyl coenzyme A. Meanwhile the inhibition of miR-26a expression induced inverse biological effects.
MiR-26a regulates glucose metabolism of colorectal cancer cells by direct targeting the PDHX, which inhibits the conversion of pyruvate to acetyl coenzyme A in the citric acid cycle.
能量代谢重编程一直是癌细胞新出现的一个特征。微小RNA在葡萄糖代谢中发挥重要作用。
通过生物信息学工具预测微小RNA-26a（miR-26a）的靶标。使用双荧光素酶报告基因检测法评估miR-26a与丙酮酸脱氢酶蛋白X组分（PDHX）mRNA的3'-非翻译区（UTR）结合的效力。分别通过实时PCR和蛋白质印迹分析对几种结肠癌细胞系中PDHX在mRNA和蛋白质水平的表达进行定量。通过检测葡萄糖消耗、乳酸、丙酮酸和乙酰辅酶A的生成量来确定miR-26a对葡萄糖代谢的影响。
在几种具有不同恶性潜能的结肠癌细胞系中，miR-26a的表达与其靶向蛋白PDHX的水平呈负相关。miR-26a通过直接靶向PDHX mRNA的3'-UTR抑制PDHX表达。在生理条件下，结肠癌细胞中的葡萄糖消耗和乳酸浓度均比正常结肠黏膜上皮细胞大幅增加。HCT116细胞中miR-26a的过表达有效促进了丙酮酸的积累并降低了乙酰辅酶A的生成。同时，抑制miR-26a的表达诱导了相反的生物学效应。
miR-26a通过直接靶向PDHX调节结肠癌细胞的葡萄糖代谢，这抑制了柠檬酸循环中丙酮酸向乙酰辅酶A的转化。
