PKN2通过下调结肠癌细胞VEGFA与bFGF分泌抑制肿瘤血管新生的机制研究

Tumor neovascularization is an important feature of colon cancer. Antitumor angiogenesis is an important treatment strategy for colon cancer. VEGFA and bFGF secreted by colon cancer cells under the stimulation of hypoxia or inflammation play a critical role in the tumor angiogenesis. Our previous study reported the tumor suppressor effect of Protein kinase N2 (PKN2) in colon cancer for the first time, but it has not been reported whether PKN2 is involved in tumor neovascularization. Our preliminary experimental results showed that the expression of PKN2 was negatively correlated with the microvessel density of colon cancer. Experiment of tumor cells and nude mice showed that overexpression of PKN2 inhibited angiogenesis of colon cancer, as well as reduced the expression and secretion of VEGFA and bFGF in the colon cancer cells. We propose that PKN2 inhibit growth and metastasis of colon cancer by inhibiting the secretion of VEGFA and bFGF and further inhibiting tumor neovascularization. This research is intended to explore the effect of PKN2 on the secretion of VEGFA and bFGF as well as the proangiogenic effect effect of colon cancer cellsunder different culture conditions. The regulatory mechanism of PKN2 on the expression and secretion of VEGFA and bFGF in colon cancer cells will also be explored.Moreover,the effectof PKN2 on tumor neovascularization and prognosis of colon cancerwill be investigated in vivo experiment and in clinical specimen. Our study may reveal new therapeutic targets for colon cancer.

血管新生是结肠癌的重要特征，抗肿瘤血管生成是结肠癌的重要治疗策略。结肠癌细胞在缺氧和炎症刺激下分泌的VEGFA和bFGF在肿瘤血管新生过程中起重要作用。我们既往研究首次报道蛋白激酶N2（PKN2）在结肠癌中的抑癌作用，但其是否参与肿瘤血管新生尚未见报道。预实验结果表明：PKN2的表达与结肠癌组织微血管密度呈负相关；体外和体内实验结果显示,过表达PKN2可抑制结肠癌血管新生并减少结肠癌细胞表达和分泌VEGFA及bFGF。就此我们提出假设：PKN2通过抑制结肠癌细胞分泌VEGFA和bFGF，抑制血管新生，从而抑制结肠癌生长和转移。本项目拟探究不同培养条件下PKN2对结肠癌细胞分泌VEGFA和bFGF及促血管新生作用的影响；探究PKN2抑制结肠癌细胞VEGFA和bFGF表达和分泌的机制；进一步在体内实验和临床标本中验证PKN2对结肠癌血管新生和预后的影响。本研究将为结肠癌的治疗寻找新的靶点。

血管新生是结肠癌的重要特征，抗肿瘤血管生成是结肠癌的重要治疗策略。结肠癌细胞在缺氧和炎症刺激下分泌的VEGFA和bFGF在肿瘤血管新生过程中起重要作用。我们既往研究首次报道蛋白激酶N2（PKN2）在结肠癌中的抑癌作用，但其是否参与肿瘤血管新生尚未见报道。我们的预实验结果表明：PKN2的表达与结肠癌组织微血管密度呈负相关；体外和体内实验结果显示,过表达PKN2可抑制结肠癌血管新生并减少结肠癌细胞表达和分泌VEGFA及bFGF。.本项目在细胞水平，进一步确认了PKN2可以抑制结肠癌细胞对血管内皮细胞的促血管形成作用。体内实验明确了PKN2抑制肿瘤组织中微血管形成的效应。临床标本实验也证实了PKN2表达与血管形成呈现负相关。机制方面，我们进一步筛选并验证出HIF1a是PKN2的主要作用靶点，PKN2是通过抑制Erk1/2磷酸化抑制HIF1a起作用的。我们在动物实验及临床标本上对该通路进行了验证。.我们的主要研究结果如下：1.PKN2过表达可抑制5-FU和缺氧诱导的结肠癌细胞促肿瘤血管形成作用；2.PKN2过表达可抑制5-FU和缺氧诱导的结肠癌细胞表达和分泌VEGFA及bFGF；3.PKN2过表达的结肠癌细胞HIF1a缺氧信号通路被抑制，同时HIF1a如何减少；4.PKN2通过与DUSP6相互结合，促进其抑制Erk1/2磷酸化，大道抑制HIF1a入核激活的作用；5.临床标本和小鼠肿瘤组织标本中，PKN2与HIF1a入核水平呈负相关。