中文摘要：

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-1a（HIF-1仪）是调控肿瘤细胞糖酵解相关基因表达的重要转录因子，而P13K信号在肿瘤细胞中可上调HIF-1仪表达。目的：探讨P13K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（10～100txmoL／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-1仪、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-1a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-1a、PKM2表达和糖酵解水平的抑制作用。结论：LY294002可通过阻断P13K／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-1a介导了糖酵解的抑制过程。

英文摘要：

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.