卵巢癌是世界范围内最致命的妇科恶性肿瘤,转移率高,预后差。癌症相关成纤维细胞(CAFs),构成肿瘤微环境主要组成部分的异质细胞群,分泌载有蛋白质的细胞外囊泡(EV),脂质,和RNA促进肿瘤发生。然而,目前尚不清楚EV中所含CAF衍生蛋白在卵巢癌中的具体作用.使用基因表达微阵列分析,我们确定了α-SMA+CAF和FAP+CAF亚群之间失调的基因列表,从中选择分泌性白细胞蛋白酶抑制剂(SLPI)进行进一步验证。定量PCR,westernblot,免疫组织化学,和酶联免疫吸附试验用于评估卵巢癌细胞中SLPI的表达,组织,CAF,和EVS。此外,我们评估了外源性SLPI对增殖的影响,迁移,入侵,和卵巢癌细胞的体外粘附。我们的结果显示SLPI蛋白在CAFs中上调,特别是在FAPhighα-SMAlowCAF亚群中,与肿瘤分级增加和总生存期(OS)降低相关。重要的是,CAF衍生的SLPI蛋白可以封装在电动汽车中,用于递送至卵巢癌细胞,从而促进细胞增殖,迁移,入侵,和粘附通过激活PI3K/AKT和下游信号通路。此外,在卵巢癌患者中,血浆中包裹的SLPI的高表达与肿瘤分期密切相关.我们的集体结果首次强调了CAFs分泌的血浆EV包裹的SLPI在肿瘤进展中的致癌作用。支持其作为卵巢癌预后生物标志物的潜在用途。
Ovarian cancer is the most lethal gynecological malignancy worldwide with high metastasis and poor prognosis rates. Cancer-associated fibroblasts (CAFs), a heterogeneous population of cells that constitutes a major component of the tumor microenvironment, secrete extracellular vesicles (EVs) loading with proteins, lipids, and RNAs to promote tumorigenesis. However, the specific roles of CAF-derived proteins contained in EVs in ovarian cancer remain poorly understood at present. Using the gene expression microarray analysis, we identified a list of dysregulated genes between the α-SMA+ CAF and FAP+ CAF subpopulations, from which secretory leukocyte protease inhibitor (
SLPI) was chosen for further validation. Quantitative PCR, western blot, immunohistochemistry, and enzyme-linked immunosorbent assays were used to assess
SLPI expression in ovarian cancer cells, tissues, CAFs, and EVs. Additionally, we evaluated the effects of exogenous SLPI on proliferation, migration, invasion, and adhesion of ovarian cancer cells in vitro. Our results showed SLPI protein was upregulated in CAFs, particularly in the FAPhigh α-SMAlow CAF subpopulation, and associated with increased tumor grade and decreased overall survival (OS). Importantly, CAF-derived
SLPI protein could be encapsulated in EVs for delivery to ovarian cancer cells, thus facilitating cell proliferation, migration, invasion, and adhesion via activating the PI3K/AKT and downstream signaling pathways. Moreover, high plasma expression of
SLPI encapsulated in EVs was closely correlated with tumor stage in ovarian cancer patients. Our collective results highlight an oncogenic role of plasma EV-encapsulated
SLPI secreted by CAFs in tumor progression for the first time, supporting its potential utility as a prognostic biomarker of ovarian cancer.