背景:AZGP1表达缺失是与去势抵抗进展相关的生物标志物,转移的发展,和前列腺癌的疾病特异性生存率低。然而,据报道,AZGP1细胞在前列腺癌中的高表达可增加增殖和侵袭。AZGP1在前列腺癌进展中的确切作用仍然难以捉摸。
方法:使用慢病毒系统产生AZGP1敲除和过表达的前列腺癌细胞。通过体外细胞增殖评估AZGP1在前列腺癌细胞中低表达或过表达的影响,迁移,和入侵检测。杂合AZGP1±小鼠从欧洲小鼠突变体档案(EMMA)获得,在2、6和10个月时收集纯合敲除雄性小鼠的前列腺组织用于组织学分析。由AZGP1低表达或过表达的前列腺癌细胞产生的体内异种移植物用于确定AZGP1在前列腺癌肿瘤生长中的作用。随后进行蛋白质组学分析以阐明AZGP1在前列腺癌进展中的作用机制.在215个独立患者样品的组织微阵列上测量人前列腺癌样品中的AZGP1表达和微血管密度。
结果:AZGP1基因敲除或过表达对前列腺癌细胞增殖均无显著影响,克隆生长,迁移,或体外入侵。AZGP1-/-小鼠的前列腺最初似乎具有大致正常的形态;然而,我们在6个月时观察到小鼠前列腺的腺泡周围间质纤维化和血管密度增加。在PC3和DU145小鼠异种移植物中,AZGP1的过表达不影响肿瘤生长.相反,与来自PC3和DU145对照细胞的异种移植物相比,这些肿瘤显示出降低的微血管密度,表明AZGP1具有抑制前列腺癌血管生成的作用。蛋白质组学分析进一步表明,与对照异种移植物相比,过表达PC3的AZGP1异种移植物富含血管生成途径蛋白,包括YWHAZ,EPHA2、SERPINE1和PDCD6、MMP9、GPX1、HSPB1、COL18A1、RNH1和ANXA1。体外功能研究表明AZGP1抑制人脐静脉内皮细胞增殖,迁移,管状形成和分支。此外,肿瘤微阵列分析显示人前列腺癌组织中AZGP1的表达与血管密度呈负相关。
结论:AZGP1是血管生成的负调节因子,这样AZGP1的丢失促进前列腺癌的血管生成。AZGP1可能对肿瘤微环境中的细胞产生异型效应,如基质细胞和内皮细胞。这项研究揭示了AZGP1在前列腺中的抗血管生成特性,并提供了靶向AZGP1抑制前列腺癌进展的基本原理。
BACKGROUND: Loss of
AZGP1 expression is a biomarker associated with progression to castration resistance, development of metastasis, and poor disease-specific survival in prostate cancer. However, high expression of AZGP1 cells in prostate cancer has been reported to increase proliferation and invasion. The exact role of
AZGP1 in prostate cancer progression remains elusive.
METHODS: AZGP1 knockout and overexpressing prostate cancer cells were generated using a lentiviral system. The effects of AZGP1 under- or over-expression in prostate cancer cells were evaluated by in vitro cell proliferation, migration, and invasion assays. Heterozygous AZGP1± mice were obtained from European Mouse Mutant Archive (EMMA), and prostate tissues from homozygous knockout male mice were collected at 2, 6 and 10 months for histological analysis. In vivo xenografts generated from AZGP1 under- or over-expressing prostate cancer cells were used to determine the role of AZGP1 in prostate cancer tumor growth, and subsequent proteomics analysis was conducted to elucidate the mechanisms of
AZGP1 action in prostate cancer progression. AZGP1 expression and microvessel density were measured in human prostate cancer samples on a tissue microarray of 215 independent patient samples.
RESULTS: Neither the knockout nor overexpression of AZGP1 exhibited significant effects on prostate cancer cell proliferation, clonal growth, migration, or invasion in vitro. The prostates of AZGP1-/- mice initially appeared to have grossly normal morphology; however, we observed fibrosis in the periglandular stroma and higher blood vessel density in the mouse prostate by 6 months. In PC3 and DU145 mouse xenografts, over-expression of AZGP1 did not affect tumor growth. Instead, these tumors displayed decreased microvessel density compared to xenografts derived from PC3 and DU145 control cells, suggesting that AZGP1 functions to inhibit angiogenesis in prostate cancer. Proteomics profiling further indicated that, compared to control xenografts, AZGP1 overexpressing PC3 xenografts are enriched with angiogenesis pathway proteins, including YWHAZ, EPHA2, SERPINE1, and PDCD6, MMP9, GPX1, HSPB1, COL18A1, RNH1, and ANXA1. In vitro functional studies show that AZGP1 inhibits human umbilical vein endothelial cell proliferation, migration, tubular formation and branching. Additionally, tumor microarray analysis shows that AZGP1 expression is negatively correlated with blood vessel density in human prostate cancer tissues.
CONCLUSIONS: AZGP1 is a negative regulator of angiogenesis, such that loss of
AZGP1 promotes angiogenesis in prostate cancer. AZGP1 likely exerts heterotypical effects on cells in the tumor microenvironment, such as stromal and endothelial cells. This study sheds light on the anti-angiogenic characteristics of AZGP1 in the prostate and provides a rationale to target
AZGP1 to inhibit prostate cancer progression.