Glypican-5抑制肺腺癌淋巴管生成和淋巴结转移的机制研究

GPC5是前期筛选获得的一条与肺腺癌淋巴结转移程度显著负相关的抑癌基因。已发现：①过表达GPC5的肺腺癌细胞株H1693与人淋巴管内皮细胞hLECs共培养后，淋巴管形成能力及细胞活力显著下降；②人肺腺癌免疫组化显示GPC5表达与淋巴管密度负相关；③表达谱芯片、生物信息学分析及验证提示：过表达GPC5可下调促淋巴管生成因子FGF2表达。故我们提出“GPC5 通过调控FGF2 信号通路抑制肺腺癌淋巴结转移”这一科学假说，并拟以两种高淋巴转移性肺腺癌细胞株和hLECs为对象，采用过表达/沉默策略，进行体内外实验，证实GPC5可抑制淋巴管生成及淋巴结转移；以FGF2为机制线索，阐明GPC5抑制肺腺癌淋巴结转移的分子机制；结合高通量组织芯片，临床大样本验证GPC5-FGF2通路与淋巴结转移的相关性。有关GPC5抑制肺腺癌淋巴结转移的功能和机制研究国内外尚未见报道，本研究将为肺腺癌防治提供新思路。

Phosphatidylinositol protein 5 (glypican-5, GPC5) is a tumor suppressor gene which had a significant negative correlation with lymph node metastasis of lung adenocarcinoma and validated by our previous key research. We previously found that: ①Lung adenocarcinoma cell line H1693 with overexpressed GPC5 gene was co-cultured with human lymphatic endothelial cells (hLECs), and the ability of lymphatic vessel formation and cell viability had dropped significantly; ②There was a significant negative correlation between GPC5 expression level and .lymphatic vessel density; ③The results of gene expression profiling, bioinformatics analysis and validation showed that overexpressing GPC5 could induce the downregulation of lymphangiogenesis factor-FGF2 expression. So we hypothesized that GPC5 was able to inhibit lymph node metastasis of lung adenocarcinoma by regulating FGF2 signaling pathway. In this proposal, firstly, we plan to clarify the functional role of GPC5 in lymphangiogenesis of lung adenocarcinoma. To achieve this goal, we design to over-express and knock-down GPC5 both in vivo and in vitro (in two separated high lymphatic metastatic lung adenocarcinoma cell lines and lymphatic endothelial cell line) and evaluate the impact of GPC5 on lymphangiogenesis and lymph node metastasis of lung adenocarcinoma. Secondly, we aim to explore how GPC5 exerts its regulatory function through FGF2 signaling pathway. Thirdly, combining with tissue microarray, we would validate the correlation between GPC5-FGF2 signaling pathway and lymph node metastasis. To date, no data is available about the function and mechanism of GPC5 inhibited lymph node metastasis of lung adenocarcinoma at home or abroad. Our study can provide new ideas for the prevention and treatment of lung adenocarcinoma.