摘要
背景:有氧糖酵解是肿瘤细胞的特征性表型之一,靶向糖酵解有望成为一种有效的肿瘤治疗策略。M2型丙酮酸激酶(PKM2)在肿瘤组织中呈高表达,参与肿瘤细胞的有氧糖酵解。缺氧诱导因子-1α(HIF-1α)是调控肿瘤细胞糖酵解相关基因表达的重要转录因子,而PI3K信号在肿瘤细胞中可上调HIF-1α表达。目的:探讨PI3K特异性抑制剂LY294002对人胃腺癌细胞增殖和糖酵解水平的影响及其可能机制。方法:以不同浓度LY294002(10～100μmol/L)在不同条件下(常氧或缺氧)处理人胃腺癌细胞株BGC-823,CCK-8实验和流式细胞分析检测细胞增殖和细胞凋亡,蛋白质印迹法检测p-Akt、p-mTOR、HIF-1α、PKM2表达,比色法检测反映糖酵解水平的胞内乳酸脱氢酶活性和胞外乳酸浓度。结果:LY294002可呈浓度和时间依赖性地抑制BGC-823细胞增殖,在较高浓度时可诱导细胞早期凋亡。LY294002可呈浓度依赖性地抑制p-Akt、p-mTOR、HIF-1α表达,在较高浓度时可抑制PKM2表达,同时降低糖酵解水平。缺氧诱导可消除LY294002对HIF-1α、PKM2表达和糖酵解水平的抑制作用。结论:LY294002可通过阻断PI3K/Akt/mTOR信号通路抑制人胃腺癌细胞增殖及其糖酵解水平,而HIF-1α介导了糖酵解的抑制过程。
Aerobic glycolysis is considered as a characteristic phenotype of cancer cells, which makes it to be a promising target for cancer therapy. Pyruvate kinase M2 isoform （PKM2） is highly expressed and crucial for aerobic glycolysis in cancer cells. As an important transcription factor for glycolytic genes, hypoxia-inducible factor 1a （HIF-1a） is up-regulated by PI3K signaling in cancer cells. Aims： 3＇0 investigate the effect of L＇/294002, a specific PI3K inhibitor, on proliferation and glycolysis in human gastric adenocarcinoma cells and its possible mechanism. Methods： Human gastric adenocarcinoma cell line BGC-823 was treated with LY294002 at different concentrations （10-100 μmol/L） and under different conditions （normoxia or hypoxia）. CCK-8 assay and flow cytometry were used to assess cell proliferation and apoptosis; Western blotting was applied to determine the expressions of p-Akt, p-mTOR, HIF-1a and PKM2; chromatometry was employed to detect intracellular lactate dehydrogenase and extracellular lactic acid, which were considered as markers of glycolysis. Results： LY294002 inhibited the proliferation of BGC-823 ceils in a concentration- and time-dependent manner; when used at a higher concentration, it could induce early apoptosis. Also, LY294002 inhibited the expressions of p-Akt, p-mTOR and HIF-1a in a concentration-dependent manner, while PKM2 and glycolysis were inhibited at a higher concentration. Hypoxia could abolish the inhibitory effect of LY294002 on HIF-1a and PKM2 expressions and glycolysis. Conclusions ： LY294002 can inhibit the proliferation of human gastric adenocarcinoma ceils and its glycolysis by blocking the PI3K/Akt/mTOR signaling pathway, and the inhibition of glycolysis is mediated by HIF-1a.
出处
《胃肠病学》
2013年第5期260-265,共6页
Chinese Journal of Gastroenterology
基金
国家自然科学基金青年科学基金项目(81101814)资助
