Inhibition of in vivo tumorigenicity and invasiveness of a human glioblastoma cell line transfected with antisense uPAR vectors

Our previous studies showed that glioblastomas express increased urokinase-type plasminogen activator receptors (uPARs) in comparison to low-grade gliomas (Yamamoto et al., Cancer Res., 54, 5016-5020, 1994). To explore whether downregulation of uPAR inhibits tumor formation and invasiveness, a human glioblastoma cell line was transfected with a cDNA construct corresponding to 300 bp of the human uPAR's 5¢ end in an antisense orientation, resulting in a reduced number of uPA receptors. Co-culture studies with tumor spheroids and fetal rat brain aggregates showed that antisense SNB19-AS1 cells expressing reduced uPAR failed to invade fetal rat brain aggregates. Intracerebral injection of SNB19-AS1 stable transfectants failed to form tumors and were negative for uPAR expression in nude mice. Thus uPAR appears in this model to be essential for tumorigenicity and invasion of glioblastomas in vivo.     

uPAR在人毛囊发育中的表达及其规律

目的 探讨人胚胎毛囊形成发育过程中,尿激酶型纤溶酶原激活剂受体（uPAR）的表达及其规律。方法 用免疫细胞化学和原位杂交分别对人胚胎毛囊起始期、延长期、分化期和胎毛阶段的表皮及毛囊的uPAR蛋白及mRNA的表达进行了检测,用图像分析系统进行了定量测定。结果 uPAR在起始期和延长期的整个毛囊中有表达,在分化期和胎毛前期毛囊的外根鞘有表达。在起始期、延长期、分化期和胎毛阶段前期表皮的基底层、最外层细胞有阳性表达。阳性表达在延长期最高,呈现出先增后减的趋势。结论 uPAR与角质形成细胞的增殖和迁移密切相关。     

uPA、uPAR、nm23-H1在大肠癌中的表达及其与肿瘤侵袭和转移的关系

 目的探讨尿激酶型纤溶酶原激活剂(uPA)、尿激酶型纤溶酶原激活剂受体(uPAR)和nm23H1基因蛋白在大肠癌中的表达及其与肿瘤侵袭和淋巴结转移的关系。方法应用免疫组化SABC法,对121例大肠癌手术根治标本进行uPA、uPAR和nm23H1基因蛋白测定。结果uPA、uPAR和nm23H1阳性表达率分别为62%、74%和48%。uPA和uPAR高表达与大肠癌侵袭和淋巴结转移关系密切(P<0.05)。nm23H1基因蛋白的低表达与大肠癌分化程度和淋巴结转移密切相关(P<0.05)。大肠癌中uPA和nm23H1蛋白表达呈负相关(P<0.05)。结论uPA、uPAR和nm23H1基因蛋白表达与大肠癌侵袭和转移有显著相关性;同时检测uPA和nm23H1表达状况,可作为预测大肠癌淋巴结转移及预后的有用指标。     

肺血栓栓塞症大鼠血浆尿激酶型纤溶酶原激活物及其受体的动态变化及其意义

目的观察大鼠肺血栓栓塞症(PTE)后不同时间血浆尿激酶型纤溶酶原激活物(uPA)和尿激酶型纤溶酶原激活物受体(uPAR)的动态变化,并探讨两者与血栓自溶率的相关性。方法经颈外静脉注入加热125I-标记纤维蛋白原自体血栓,复制大鼠PTE模型,随机分组如下:1)正常对照组;2)PTE组:又分为PTE 4 h组(PTE 4 h)、PTE 24 h组(PTE 24 h)、PTE 3 d组(PTE 3d)、PTE 5 d组(PTE 5 d),即分别在造模成功后观察4 h2、4 h3、d、5 d后处死小鼠,留取血浆标本测定uPA、uPAR的水平;留取左肺观察肺组织病理改变;留取心脏、肺脏、全血以计算血栓自溶率。结果血浆uPA、uPAR水平在PTE后4 h略有上升(P>0.05),PTE后24 h明显增加(P<0.05),3 d时最高(P<0.01),5 d时开始下降,但仍明显高于正常对照组(uPAP<0.05,uPARP<0.01);PTE后4 h组、24 h组、3 d组血浆uPA质量浓度与血栓自溶率正相关(4 hr=0.758,P<0.05;24 hr=0.764,P<0.05;3 dr=0.778,P<0.05),血浆uPAR质量浓度与血栓自溶率正相关(4 hr=0.701,P<0.05;24 hr=0.764,P<0.05;3 dr=0.777,P<0.05)。肺组织病理改变:PTE后4 h有少量继发血栓形成,血栓及血管壁内可见白细胞浸润;PTE后3 d、5 d见注入的血凝块明显溶解,代之以新形成的血栓。结论PTE后血浆uPA、uPAR水平增加,促进内源性纤维蛋白溶解。     

Plasminogen activator inhibitor-1 is an aggregate response factor with pleiotropic effects on cell signaling in vascular disease and the tumor microenvironment

In hemostasis, the serine protease inhibitor (serpin) plasminogen activator inhibitor-1 (PAI-1) functions to stabilize clots via inhibition of tissue plasminogen activator (tPA) with subsequent inhibition of fibrinolysis. In tissues, PAI-1 functions to inhibit extracellular matrix degradation via inhibition of urokinase plasminogen activator (uPA). Elevated levels of PAI-1 in the vasculature and in tissues have long been known to be associated with thrombosis and fibrosis, respectively. However, there is emerging evidence that PAI-1 may participate in the pathophysiology of a number of diseases such as atherosclerosis, restenosis, and cancer. In many of these disease states, the canonical view of PAI-1 as an inhibitor of tPA and uPA cannot fully account for a mechanism whereby PAI-1 contributes to the disease. In these cases, one must consider recent data, which indicates PAI-1 can directly promote pro-proliferative and anti-apoptotic signaling in a variety of cell types. Given the wide variety of inflammatory, hormonal, and metabolic signals that increase PAI-1 expression, it is important to consider mechanisms by which PAI-1 can directly participate in disease etiology.     

uPA‐uPAR molecular complex is involved in cell signaling during neuronal migration and neuritogenesis

Background: In the development of the central nervous system (CNS), neuronal migration and neuritogenesis are crucial processes for establishing functional neural circuits. This relies on the regulation exerted by several signaling molecules, which play important roles in axonal growth and guidance. The urokinase‐type plasminogen activator (uPA)—in association with its receptor—triggers extracellular matrix proteolysis and other cellular processes through the activation of intracellular signaling pathways. Even though the uPA‐uPAR complex is well characterized in nonneuronal systems, little is known about its signaling role during CNS development. Results : In response to uPA, neuronal migration and neuritogenesis are promoted in a dose‐dependent manner. After stimulation, uPAR interacts with α₅‐ and β₁‐integrin subunits, which may constitute an αβ‐heterodimer that acts as a uPA‐uPAR coreceptor favoring the activation of multiple kinases. This interaction may be responsible for the uPA‐promoted phosphorylation of focal adhesion kinase (FAK) and its relocation toward growth cones, triggering cytoskeletal reorganization which, in turn, induces morphological changes related to neuronal migration and neuritogenesis. Conclusions : uPA has a key role during CNS development. In association with its receptor, it orchestrates both proteolytic and nonproteolytic events that govern the proper formation of neural networks. Developmental Dynamics 243:676–689, 2014. © 2014 Wiley Periodicals, Inc.     

Urokinase and its receptor in follicular and inflammatory cysts of the jaws

Oral Diseases (2010) 16 , 753–759 Objective: Proteases are considered critical in peri‐cystic tissue degradation required in jaw cyst expansion. We studied the expression of the plasminogen activation system (plasminogen activators; their inhibitor type‐1, PAI‐1; the receptor for the urokinase‐type plasminogen activator, uPAR) in follicular and inflammatory cysts of the jaw, to identify a possible role of this system in jaw cyst enlargement. Materials and Methods: Jaw cysts were collected by therapeutic enucleation. ELISA and casein zymography were used to measure and characterize plasminogen activators in cyst fluid. By immunohistochemistry we examined the presence of uPAR in cyst walls and inflammatory cells, and by Western blotting the molecular forms of uPAR within the cyst fluid. Results: Inflammatory cysts fluid contained higher amounts of plasminogen activators of the urinary‐type (uPA), and lower amounts of PAI‐1, when compared to follicular cysts fluid. Epithelial layers of both types of cysts and inflammatory cells expressed uPAR. Native 3‐domain uPAR was scarcely detectable within cysts, where its cleavage was accounted for by uPA. Conclusion: These data suggest a plasminogen activation‐dependent mechanism of cyst enlargement, where only the outward uPAR expressed on epithelial cells and on inflammatory cells direct the peri‐cystic protease cascade, in a way similar to tumor enlargement within tissues.     

Enhanced levels of urokinase plasminogen activator and its soluble receptor in common variable immunodeficiency

Common variable immunodeficiency (CVID) is a heterogeneous syndrome characterized by defective immunoglobulin production and high frequency of bacterial infections, autoimmunity and manifestations of chronic inflammation.The urokinase plasminogen activator (uPA), its cell bound and soluble receptor (uPAR, suPAR) have complex biological functions involving innate immune defense mechanisms and regulation of inflammation. Based on this dual role, we hypothesized that the uPA system could be affected in CVID, and examined expression of components of the uPA system in subgroups of CVID. All CVID-patients had increased plasma levels of suPAR with particularly high levels in those with splenomegaly and thrombocytopenia. Plasma uPA levels were also raised in these patients, and both suPAR and uPA levels correlated with the monocyte activation marker neopterin. Monocytes from CVID patients had increased expression of uPAR. We show an increased activation of the uPA system possibly contributing to the inflammatory phenotype seen in subgroups of CVID patients.     

Prognostic significance of urokinase plasminogen activator receptor and its cleaved forms in blood from patients with non‐small cell lung cancer

Urokinase plasminogen activator (uPA) cleaves its three‐domain cell surface receptor, uPAR, liberating domain I [uPAR(I)] and leaving the cleaved uPAR(II‐III) on the cell surface. Both intact and cleaved uPAR can be shed from the cell surface. uPAR(I) was previously shown to be a prognostic factor in lung tumour extracts. Here we analyse uPAR forms in blood from patients with non‐small cell lung cancer (NSCLC). Preoperatively sampled plasma/serum from 32 patients with NSCLC was analysed. Three time‐resolved fluoroimmunoassays (TR‐FIAs) measuring intact uPAR(I‐III) (TR‐FIA 1), uPAR(I‐III) + uPAR(II‐III) (TR‐FIA 2) and uPAR(I) (TR‐FIA 3) were applied. The Spearman rank correlations between plasma and serum levels of uPAR(I‐III), uPAR(I‐III) + uPAR(II‐III), and uPAR(I) were 0.89, 0.94 and 0.68 respectively. Survival analysis demonstrated that high levels of all uPAR forms were associated with shorter survival. Adjusted for histological subtype high plasma uPAR(I‐III) and uPAR(I) levels as well as serum uPAR(I) levels were significantly associated with shorter OS (hazards ratios = 4.3, 2.8 and 3.8 respectively). High blood levels of intact uPAR and its cleaved forms are associated with poor prognosis in NSCLC.