Gene X通过上调HIF-1活性促进肿瘤生长
Under hypoxic microenvironment，HIF-1 is known to play an important role in cellular adaptive response to hypoxia，and up-regulates various gene expressions related to angiogenesis，glycolysis，invasion and metastasis of cancer cells。Moreover，HIF-1 has been strongly associated with tumor radioresistance。So HIF-1 is an effective target for anticancer therapy。Until now，there are many kinds of HIF-1 inhibitors，but unfortunately there is no one which could inhibi HIF-1 activity with high efficiency. To overcome the problem caused by HIF-1，it is critical to elucidate molecular mechanism behind the regulation of HIF-1 activity。Especially，finding novel genes responsible for the activation of HIF-1 is important，because we can exploit it as a therapeutic target to inhibit HIF-1 activity。First we established a screening system to select novel genes which could up-regulate HIF-1 activity。We have already gotten several novel genes up-regulating HIF-1 activity。Gene X is one of them。How about the function of Gene X and the mechanism of up-regulating HIF-1 activity? We constructed an expression vector for Gene X，and performed a reporter gene assay to confirm that Gene X induces HIF-1 activity using our HIF-l-dependent reporter gene SHRE-Luc reporter gene，and also knockdown of Gene X resulted in the suppression of HIF-1 activity。Using a different kind of reporter gene composed of oxygen-dependent degradation domain of HIF-lalpha and luciferase，we can monitor the stability of HIF-lalpha protein as luciferase bioluminescence。Overexpression of Gene X induced luciferase activity from the ODD-Luc fusion protein，and knockdown of Gene X significantly suppressed the luciferase activity。These results indicate that Gene X stabilizes HIF-1 protein。Using western blotting and Luciferase activity assay to check HIF-1 protein level and luciferase activity ，we found Gene X prolongs the half life of HIF-l.We confirmed that overexpression of Gene X increased HIF-1 expressioi suppressed HIF-1 expression level。Using real-time PCR，we found Gene X overexpression results in HIF-l”s downstream genes such as VEGF，PDGF and bFGF2 mRNA expression increasing。Also we found Gene X knock down decreased HIF-la”s downstream genes such as VEGF，PDGF and bFGF2 mRNA expression。We established stable cancer cell lines constitutively expressing Gene X and knocked down Gene X to examined whether Gene X influences tumor growth or not。The results showed that overexpression of Gene X accelerated tumor growth after the transplantation，and tumor growth of Gene X knockdown cells was significantly delayed compared to control. So far，we thought: Gene X induces HIF-1 activity，and stabilizes and prolongs half life of HIF-1 to accelerate the tumor growth;Knockdown of Gene X decrease HIF-1 activity and,decreases MVD and results in the tumor growth delay;Gene X might be a potential target for cancer therapy.
肿瘤病因学 HIF-1基因 分子活性 Gene X基因 调控机制
曾丽华 李予蓉 郭国祯 原田浩 林艳云 苗霞 赵涛 李康樗 刘军叶 谢学军 任东青
第四军医大学军事预防医学院放射医学教研室,陕西西安 710032
国内会议
苏州
中文
172-173
2014-05-11（万方平台首次上网日期，不代表论文的发表时间）