人附睾蛋白4（HE4）调控TGF-β表达介导上皮间质转化（EMT）促进肺癌转移的分子机制及临床意义

Lung cancer is the most prevalent and deadly malignancy in our country and world. It is urgently wanted to overcome the metastasis and recurrence of lung cancer in clinic, in which process epithelial-mesenthymal transition (EMT) plays a pivotal role. Recent studies show that human epididymis protein 4(HE4), a small secreted glycoprotein of serine protenase inhibitor, is overexpressed in the tumor tissues of lung cancer with HE4 overexpression closely correlating with the poor therapy response and prognosis in patients with lung cancer. Our preliminary data show that overxpression of HE4 in lung cancer cells induces TGF-β secretion and consequently promotes the EMT and metastasis of lung cancer cells. In this study, we aim to further validate the effect of HE4 expression on EMT and metastasis of lung cancer cells by lentivirus-mediated gene overexpression and shRNA knockdown in vitro and in vivo, to define the mechanisms by which HE4 promotes the production of TGF-β in lung cancer cells using specific neutralizing antibodies, inhibitors and transfection of HE4 gene deficient of enzyme activity, and finally to evaluate the correlations among HE4 level and TGF-β level in sera and tumors and tumor metastasis in a cohort of lung cancer patients. This study would reveal the biological effects and melecular mechanisms of HE4 in the progression of lung cancer, and potentially provide the novel target for prevention and treatment of lung cancer metastasis.

肺癌已成为我国乃至全球发病率及死亡率最高的恶性肿瘤，克服肺癌复发和转移是临床治疗中亟待解决的关键问题。上皮间质转化(EMT)在介导肿瘤侵袭及转移中发挥重要作用。人附睾蛋白4(HE4)是一种具有蛋白酶抑制活性的分泌糖蛋白，研究表明HE4在肺癌患者中高表达，并与患者不良治疗反应及预后密切相关。然而，HE4在肺癌中的生物学效应和分子机制尚未阐明。我们前期发现，在肺癌细胞中过表达HE4上调了TGF-β表达，诱导肺癌细胞EMT，促进侵袭及转移。本研究中我们拟采用裸鼠成瘤实验体内明确HE4的促EMT及转移效应；采用胞外抗体及抑制剂阻断、转染酶活性缺失突变体等方法明确HE4调控TGF-β表达或释放的分子机制；评价肺癌患者血清及肿瘤组织标本中HE4、TGF-β及EMT标志蛋白及其与肿瘤转移的相关性。本项研究将揭示HE4在肺癌进展中的生物学效应及分子机制，为肺癌转移防治提供潜在干预靶点。

肺癌已成为我国乃至全球发病率及死亡率最高的恶性肿瘤，克服肺癌复发和转移是临床治疗中亟待解决的关键问题。表皮间质转化(EMT)在介导肿瘤侵袭及转移中发挥重要作用。人附睾蛋白4(HE4)是一种具有蛋白酶抑制活性的分泌糖蛋白，研究表明HE4在肺癌患者中高表达，并与患者不良治疗反应及预后密切相关。然而，HE4在肺癌病理发生中的作用机制目前未阐明。我们前期体外实验发现，在肺癌细胞中过表达HE4上调了TGF-β表达，诱导肺癌细胞EMT，促进侵袭及转移。本研究中，我们采用基因过表达及沉默方法，明确了HE4促肺癌细胞EMT及侵袭转移效应；进一步采用特异抗体、抑制剂阻断等方法发现HE4能够上调血小板结合蛋白1（TSP-1)表达，后者促进TGF-β释放，从而介导肺癌细胞EMT效应；最后，我们利用ELSIA、定量PCR、免疫印迹及组化方法检测了肺癌患者血清标本中HE4、TGF-β表达，发现血清HE4水平与TGF-β水平存在相关性。我们的研究揭示了HE4在肺癌进展中的生物学效应及分子机制，为肺癌转移防治提供潜在干预靶点。