Background Hypoxia promotes tumor angiogenesis and hypoxia-inducible factor-1 alpha （HIF-lg） plays a pivotal role in this process. Recently identified pro-angiogenic factor, semaphorin4D （Sema4D） also promotes ang...Background Hypoxia promotes tumor angiogenesis and hypoxia-inducible factor-1 alpha （HIF-lg） plays a pivotal role in this process. Recently identified pro-angiogenic factor, semaphorin4D （Sema4D） also promotes angiogenesis and enhances invasive proliferation in some tumors. Furthermore, tumor-associated macrophages （TAMs） can increase the expression of HIF-la and Sema4D in cancer cells and thus influence tumor growth and progression. The purpose of this study was to evaluate the effect of TAMs on the expression of Sema4D and HIF-la and the impact of biologic behavior in colon cancer cells. Methods Immunohistochemistry was used to analyze HIF-la and Sema4D expression in 86 curatively resected colon cancer samples and 52 normal colon tissues samples. The relationship between their expression and clinicopathological factors was analyzed. Furthermore, macrophage-tumor cell interactions, such as metastasis, angiogenesis, were also studied using in vitro co-culture systems. Statistical analysis was performed using SPSS 17.0 software （SPSS Inc., USA）. Differences between two groups were analyzed with Student＇s t test. Results HIF-la （58%） and Sema4D （60%） were expressed at a significantly higher level in tumors than in normal tissues （P 〈0.01, for both）. Furthermore, HIF-la and Sema4D expression was significantly correlated with lymphatic metastasis, specific histological types and TNM stages （P 〈0.05）, but not with age and tumor size （P 〉0.05）. Sema4D expression was correlated with that of HIF-la （r=0.567, P 〈0.01）. TAMs markedly induced HIF-la and Sema4D expression in colon cancer calls and subsequently increased their migration and invasion. Conclusions HIF-la and Sema4D expression are closely related to lymphatic metastasis, specific histological types and TNM stages in colon cancer. Furthermore, TAMs promote migration and invasion of colon cancer cells and endothelial tube formation, possibly through up-regulation of HIF-la and Sema4D.展开更多
AIM: To investigate the influence of phosphatidylinositol-3-kinase protein kinase B(PI3K/AKT)-HIF-1α signaling pathway on glycolysis in esophageal carcinoma cells under hypoxia. METHODS: Esophageal carcinoma cell lin...AIM: To investigate the influence of phosphatidylinositol-3-kinase protein kinase B(PI3K/AKT)-HIF-1α signaling pathway on glycolysis in esophageal carcinoma cells under hypoxia. METHODS: Esophageal carcinoma cell lines Eca109 and TE13 were cultured under hypoxia environment, and the protein, m RNA and activity levels of hypoxia inducible factor-1 alpha(HIF-1α), glucose transporter 1, hexokinase-Ⅱ, phosphofructokinase 2 and lactate dehydrogenase-A were determined. Supernatant lactic acid concentrations were also detected. The PI3K/AKT signaling pathway was then inhibited with wortmannin, and the effects of hypoxia on the expression or activities of HIF-1α, associated glycolytic enzymes and lactic acid concentrations were observed. Esophageal carcinoma cells were then transfected with interference plasmid with HIF-1α-targeting si RNA to assess impact of the high expression of HIF-1α on glycolysis.RESULTS: HIF-1α is highly expressed in the esophageal carcinoma cell lines tested, and with decreasing levels of oxygen, the expression of HIF-1α and the associated glycolytic enzymes and the extracellular lactic acid concentration were enhanced in the esophageal carcinoma cell lines Eca109 and TE13. In both normoxia and hypoxic conditions, the level of glycolytic enzymesand the secretion of lactic acid were both reduced by wortmannin. The expression and activities of glycolytic enzymes and the lactic acid concentration in cells were reduced by inhibiting HIF-1α, especially the decreasing level of glycolysis was significant under hypoxic conditions.CONCLUSION: The PI3K/AKT pathway and HIF-1α are both involved in the process of glycolysis in esophageal cancer cells.展开更多
基金This study was supported in part by grants from the National Youthful Science Foundation of China （No. 81101858） and the Natural Science Foundation of Shandong Province of China （No. BS2011 SW046）. Conflict of interest： none.
文摘Background Hypoxia promotes tumor angiogenesis and hypoxia-inducible factor-1 alpha （HIF-lg） plays a pivotal role in this process. Recently identified pro-angiogenic factor, semaphorin4D （Sema4D） also promotes angiogenesis and enhances invasive proliferation in some tumors. Furthermore, tumor-associated macrophages （TAMs） can increase the expression of HIF-la and Sema4D in cancer cells and thus influence tumor growth and progression. The purpose of this study was to evaluate the effect of TAMs on the expression of Sema4D and HIF-la and the impact of biologic behavior in colon cancer cells. Methods Immunohistochemistry was used to analyze HIF-la and Sema4D expression in 86 curatively resected colon cancer samples and 52 normal colon tissues samples. The relationship between their expression and clinicopathological factors was analyzed. Furthermore, macrophage-tumor cell interactions, such as metastasis, angiogenesis, were also studied using in vitro co-culture systems. Statistical analysis was performed using SPSS 17.0 software （SPSS Inc., USA）. Differences between two groups were analyzed with Student＇s t test. Results HIF-la （58%） and Sema4D （60%） were expressed at a significantly higher level in tumors than in normal tissues （P 〈0.01, for both）. Furthermore, HIF-la and Sema4D expression was significantly correlated with lymphatic metastasis, specific histological types and TNM stages （P 〈0.05）, but not with age and tumor size （P 〉0.05）. Sema4D expression was correlated with that of HIF-la （r=0.567, P 〈0.01）. TAMs markedly induced HIF-la and Sema4D expression in colon cancer calls and subsequently increased their migration and invasion. Conclusions HIF-la and Sema4D expression are closely related to lymphatic metastasis, specific histological types and TNM stages in colon cancer. Furthermore, TAMs promote migration and invasion of colon cancer cells and endothelial tube formation, possibly through up-regulation of HIF-la and Sema4D.
基金Supported by the National Natural Science Foundation of China,No.30800511
文摘AIM: To investigate the influence of phosphatidylinositol-3-kinase protein kinase B(PI3K/AKT)-HIF-1α signaling pathway on glycolysis in esophageal carcinoma cells under hypoxia. METHODS: Esophageal carcinoma cell lines Eca109 and TE13 were cultured under hypoxia environment, and the protein, m RNA and activity levels of hypoxia inducible factor-1 alpha(HIF-1α), glucose transporter 1, hexokinase-Ⅱ, phosphofructokinase 2 and lactate dehydrogenase-A were determined. Supernatant lactic acid concentrations were also detected. The PI3K/AKT signaling pathway was then inhibited with wortmannin, and the effects of hypoxia on the expression or activities of HIF-1α, associated glycolytic enzymes and lactic acid concentrations were observed. Esophageal carcinoma cells were then transfected with interference plasmid with HIF-1α-targeting si RNA to assess impact of the high expression of HIF-1α on glycolysis.RESULTS: HIF-1α is highly expressed in the esophageal carcinoma cell lines tested, and with decreasing levels of oxygen, the expression of HIF-1α and the associated glycolytic enzymes and the extracellular lactic acid concentration were enhanced in the esophageal carcinoma cell lines Eca109 and TE13. In both normoxia and hypoxic conditions, the level of glycolytic enzymesand the secretion of lactic acid were both reduced by wortmannin. The expression and activities of glycolytic enzymes and the lactic acid concentration in cells were reduced by inhibiting HIF-1α, especially the decreasing level of glycolysis was significant under hypoxic conditions.CONCLUSION: The PI3K/AKT pathway and HIF-1α are both involved in the process of glycolysis in esophageal cancer cells.
