肿瘤微环境巨噬细胞促进VCAM-1介导卵巢癌细胞侵袭及腹腔转移的研究

Ovarian carcinoma is the most lethal gynecologic malignancy, primarily owing to most patients being diagnosed at the advanced stages of disease. Its mechanism is still unclear. Vascular cell adhesion molecule-1 (VCAM-1) belongs to the immunoglobin superfamily and plays an important role in heterogenous cell-cell adhesions. It is well known that tumor cells with VLA-4 expression can adhere to endothelial or peritoneal mesothelial cells by binding of VLA-4 to VCAM-1, taking part in the metastasis of tumors. However, biological functions that VCAM-1 is expressed in tumor cells remain to be elucidated. In the previous study, we had found that VCAM-1 expression was found in 28% of ovarian carcinoma samples and was associated with worse prognosis of patients and shorter disease-free survival duration. T29H cells, which are the tumorigenic cells, expressed both VCAM-1 and inflammatory factors. The macrophages with VLA-4 expression were found in the peritoneal metastatic ovarian carcinoma samples. VCAM-1＋ ovarian cancer cells demonstrated stronger invasiveness and higher proliferative potential than VCAM-1- tumor cells. These data proposed that macrophages may activate ovarian cancer cells produce VCAM-1 and enhance tumor progression. Therefore, in the current study, we will elucidate the mechanism on tumor inflammatory microenvironment promoting VCAM-1 to mediate invasion and peritoneal metastasis in ovarian carcinoma via the signaling pathways among macrophages, VLA-4/VCAM-1, and ovarian cancer cells, using the methods of cell and molecular biology. This may develop a novel therapeutic target for the treatment of ovarian carcinoma.

卵巢癌致死率居妇科肿瘤之首，主要归因于多数患者确诊时已处于晚期，其发生机制尚不清楚。血管细胞粘附分子-1（VCAM-1）隶属免疫球蛋白超家族，生物学功能是介导异种细胞间的粘附。已知肿瘤细胞能通过VLA-4与内皮或间皮细胞VCAM-1结合，参与转移，但对肿瘤细胞自身表达VCAM-1的生物学意义并不明确。我们前期研究发现，卵巢癌细胞存在VCAM-1表达并与预后差及肿瘤复发关系密切、致瘤性T29H细胞共表达VCAM-1及炎症因子、腹腔转移性癌组织含有VLA-4＋巨噬细胞、VCAM-1＋卵巢癌细胞侵袭性及增殖活性均明显增强，提示巨噬细胞可能激活卵巢癌细胞产生VCAM-1进而促进癌细胞生长及侵袭。因此，本课题拟利用细胞及分子生物学方法，通过探讨巨噬细胞-VLA-4/VCAM-1-卵巢癌细胞信号通路，阐明肿瘤炎症性微环境促进VCAM-1介导卵巢癌侵袭及腹腔转移的分子机制，为卵巢癌治疗提供可能的靶点。

卵巢癌致死率居妇科肿瘤之首，主要归因于多数患者确诊时已处于晚期，其发生机制尚不清楚。血管细胞粘附分子-1（VCAM-1）隶属免疫球蛋白超家族，生物学功能是介导异种细胞间的粘附。已知肿瘤细胞能通过VLA-4与内皮或间皮细胞VCAM-1结合，参与肿瘤转移，但对肿瘤细胞自身表达VCAM-1的生物学意义并不明确。本课题围绕巨噬细胞—VCAM-1—卵巢癌细胞信号通路进行研究，以期阐明肿瘤炎症性微环境促进VCAM-1介导的卵巢癌侵袭及腹腔转移的具体机制。通过对人类卵巢癌组织进行原位研究，我们发现VCAM-1阳性表达主要存在于高级别浆液性癌及高级别卵巢癌组织，VCAM-1阳性表达的患者预后较差，生存时间及复发时间均明显缩短，是肿瘤复发的独立预后因素。巨噬细胞上清和TNF-alpha可显著上调VCAM-1基因启动子的转录活性，导致卵巢癌细胞VCAM-1 mRNA和蛋白表达水平升高。与空载体对照组相比，VCAM-1+卵巢癌细胞在细胞周期及迁移能力无显著差异，但细胞凋亡显著增高，细胞侵袭和克隆形成能力显著下降；巨噬细胞上清培养的VCAM-1＋卵巢癌细胞在细胞周期和凋亡方面未见显著差异，但细胞迁移、侵袭和克隆形成能力均显著增强，提示巨噬细胞能够通过上调VCAM-1表达，促进卵巢癌细胞生长、迁移和侵袭，其分子机制可能与STAT3表达和/或STAT3磷酸化有关。裸鼠体内实验结果显示，与对照组相比，VCAM-1＋卵巢癌细胞组尽管肿瘤体积和重量均显著下降，但细胞侵袭能力显著升高，较常出现骨骼肌和骨骼侵犯、远隔脏器（肺脏及胸腔淋巴结）和盆/腹腔脏器转移。本课题研究结果证实肿瘤炎症性微环境能够促进卵巢癌侵袭及转移，为未来卵巢癌临床治疗提供可能的靶点及实验依据。