乏氧诱导CCL28在肺腺癌血管生成中的作用及其机制研究

Although anti-angiogenesis therapy has becoming one of the most prospective therapies in advanced lung adenocarcinoma, its application has been impeded mainly by low objective response rate. One of the most important reasons is the alternative pathways except VEGF-VEGFR might be engaged in tumor angiogenesis, which might be a key target for enhancing anti-angiogenesis effects. It has been widely accepted that tumor hypoxia is the initiating factor for angiogenesis. Based on our previous studies on the gene expression array of lung adenocarcinoma cells under hypoxic condition, and confirmed by in vitro and in vivo studies, we speculate that hypoxia induced high expression of chemokine CCL28 might be another important pathway for angiogenesis in lung adenocarcinoma. This project is proposed to study :①the molecular mechanism of CCL28 up-regulation in lung adenocarcinoma cells under hypoxic condition; ②the molecular mechanism of pro-angiogenesis effects of CCL28 through the receptor CCR3 on endothelial cells. This study would deepen the understanding of the molecular mechanism of tumor angiogenesis and might also provide a new target for increasing objective response rate of anti-angiogenesis therapy in lung adenocarcinoma.

抗血管治疗是目前晚期肺腺癌重要治疗方法之一，但以抗VEGF为代表的抗血管药物临床客观有效率低是阻碍其临床应用的重要原因。肺腺癌可以利用其它通路促进肿瘤血管生成以拮抗对VEGF的抑制是其中重要原因之一，探索并抑制这些通路是提高临床肿瘤抗血管治疗效果的关键。目前认为乏氧(Hypoxia)是肿瘤血管生成的始动因素，本课题组前期建立细胞乏氧培养体系，通过表达芯片的筛选及体外、体内实验验证，提示乏氧通过上调肺腺癌细胞趋化因子（CCL28）的表达参与血管生成可能是肺腺癌血管生成的另一重要途径。本项目拟在前期研究的工作基础上，通过荧光素酶报告基因、肿瘤血管活体荧光成像、动态增强MRI等手段研究：①乏氧状态下肺腺癌细胞上调CCL28的分子机制；②CCL28通过作用于血管内皮细胞受体CCR3促进肺腺癌血管生成的分子机制。本研究将加深对肿瘤血管生成分子机制的认识，为提高临床肺腺癌抗血管治疗提供新的靶点。

肿瘤乏氧是肺腺癌的重要特征之一。通过建立体外乏氧模型、细胞培养及表达芯片筛选，发现趋化因子CCL28 是肺腺癌中唯一表达上调的趋化因子，并在肿瘤组织和患者血清中证实。CCL28 能促进血管内皮细胞的迁移和增殖、促进鸡胚绒毛膜和肺腺癌移植瘤血管生成。CCL28 表达与肺腺癌微血管密度正相关。CCL28的受体CCR3在血管内皮细胞中表达较高。用磷酸化抗体阵列分析 CCL28作用于血管内皮细胞的信号通路发现：CCR3 信号通路可以在 PI3K-Akt、p38 MAPK 和 PLCγ水平与VEGR/VEGFR信号通路crosstalk。这些效应可以被抗CCR3抗体中和。总之, CCL28 作为由肿瘤乏氧引起的趋化因子, 可以通过作用于微血管内皮细胞的CCR3 促进肺腺癌血管生成。