Relationships between Activators and Inhibitors of Plasminogen, and the Progression of Small Abdominal Aortic Aneurysms

OBJECTIVE: plasmin is a common activator of the known proteolytic systems involved in the aneurysmal degradation, and is reported to be associated with the expansion of abdominal aortic aneurysms (AAA). The aim of this study was to study the activating pathways of plasminogen as predictors of the progression of AAA. MATERIALS AND METHODS: one hundred and twelve of 122 male patients with a small AAA (def.: +3cm) were interviewed, examined, had blood samples taken at diagnosis, and scanned annually for 1-5 years (mean 3.5 years), and referred for surgery if the AAA exceeded 5cm in diameter.A random sample of 70 of the 112 cases had plasma levels of urokinase-like-plasminogen activator (uPA), tissue-type-plasminogen activator (tPA), plasminogen-activator-inhibitor-1 (PAI-1), macrophage inhibiting factor (MIF), tumour-growth-factor-beta1 (TGF-beta1), homocysteine, and serum levels of IgA-antibodies against Chlamydia pneumoniae (IgA-CP) and Cotinine (a nicotine metabolite) measured. Spearmans correlation analysis was used for statistics. RESULTS: the annual expansion rate correlated positively with tPA, IgA-CP and S-Cotinine; r =0.37 (p=0.002), 0.29 (p=0.006) and 0.24 (p=0.038), while PAI1, uPA, TGF-beta1, homocysteine, and MIF did not. S-Cotinine did also correlate positively with tPA, r=0.24 (p=0.049). CONCLUSION: the aortic matrix degradation in AAA may be partly caused by an activation of plasminogen by tPA, but apparently not by uPA, which usually dominates matrix degradation. Smoking seems to be a factor for this pathway, while the pathways of IgA-CP and MIF, a new marker of aneurysmal progression, seem different. The latter observations suggest that other proteolytic pathways are involved in the aortic wall degradation in AAA.     

Growth factor-dependent activation of the MAPK pathway in human pancreatic cancer: MEK/ERK and p38 MAP kinase interaction in uPA synthesis

Increased expression of the hepatocyte growth factor (HGF) receptor (c-met) and urokinase type plasminogen (uPA) correlated with the development and metastasis of cancers. To investigate the role of HGF/c-met signaling on metastasis in cancer cells stimulated with HGF, we examined the effects of a specific MEK1 inhibitor (PD98059) and a p38 MAP kinase inhibitor (SB203580) on HGF-induced uPA expression in pancreatic cancer cell lines, L3.6PL and IMIM-PC2. Pretreatment of PD98059 decreased HGF-mediated phosphorylation of extracellular receptor kinase (ERK), uPA secretion and expression of matrix metalloproteinases (MMP-2 and MMP-9) in a dose-dependent manner. In contrast, SB203580 pretreatment increased HGF-stimulated ERK phosphorylation, uPA secretion and expression of MMPs. SB203580 also reversed the inhibition of HGF-mediated ERK activation and uPA secretion in the PD98059-pretreated cells. These results suggest that ERK activation by HGF might play important roles in the metastasis of pancreatic cancer and the p38 MAPK pathway also involved in the HGF-mediated uPA secretion and metastasis by regulation of ERK pathway. This revised version was published online in July 2006 with corrections to the Cover Date.     

Antibodies to PAI-1 alter the invasive and migratory properties of human tumour cells in vitro

Recent reports suggest that elevated levels of plasminogen activator inhibitor-1 (PAI-1) may contribute to tumour progression. The studies reported here were designed to help elucidate PAI-1's contribution to the invasive and migratory phenotype. Antibodies to PAI-1 dose-dependently, and significantly, inhibited the invasive and migratory potential of human HT1080 fibrosarcoma cells, as did an antibody to uPA and the plasmin inhibitor aprotinin. Invasion of the human melanoma cell line, BLM, was also attenuated by the anti-PAI-1 monoclonal antibody MAI-12. The non-invasive human melanoma cell line, IF6, which does not express uPA, provided further confirmation of PAI-1 and uPA's role as, upon transfection with uPA, this cell line attained an invasive phenotype, which was again attenuated by MAI- 12. Although antibodies to PAI-1 did not affect the adhesion of HT1080 cells to vitronectin, the antibody to uPA reduced their attachment. Addition of exogenous PAI-1, however, prevented HT1080 cell adhesion (IC₅₀ 180nM) and promoted cell detachment from vitronectin. Furthermore melanoma cells transfected with a uPA variant, which had an impaired interaction with PAI-1, were not invasive and had impaired binding to vitronectin. These data highlight the importance of a balanced proteolysis and suggest an additional role for PAI-1 distinct from its role in proteolysis. These data also suggest that uPA and PAI-1 may co-operate in the migratory process by respectively facilitating the attachment to, and subsequent detachment from, vitronectin in the extracellular matrix. These results support the clinical findings and indicate that modulation of PAI-1 activity may be of therapeutic benefit for the treatment of cancer. This revised version was published online in July 2006 with corrections to the Cover Date.     

切应力作用下肾近端小管上皮细胞纤溶酶原激活物(tPA和uPA)表达的变化及意义

检测切应力作用下肾近端小管上皮细胞纤溶酶原激活物tPA和uPA mRNA表达的变化,探讨糖尿病肾病早期小管间质细胞外基质重塑的可能机制.用5 dyn/cm2和10 dyn/cm2的切应力处理肾近端小管上皮细胞(NRK-52E),作用时间分别为1、3和6 h,用RT-PCR法检测tPA及uPA mRNA的表达.结果表明:切应力呈大小和时间依赖性下调肾小管上皮细胞tPA及uPA mRNA的表达.在糖尿病肾病早期,高滤过引起的切应力增加可抑制肾近端小管上皮细胞tPA和uPA mRNA表达,导致肾小管间质纤维蛋白溶解活性降低,参与小管间质细胞外基质的重塑.     

抗人尿激酶受体单克隆抗体的制备与鉴定

目的　制备抗人尿激酶受体单克隆抗体,为今后ｕＰＡＲ 病理生理作用及临床意义的研究提供新的手段。方法　利用杂交瘤技术,用经ＰＭＡ刺激的Ｕ９３７ 细胞与可溶性尿激酶受体（ｓｕＰＡＲ）免疫Ｂａｌｂ／ｃ 小鼠,与ＳＰ２／０ 细胞融合。结果　获得国内第１ 组４ 株抗人尿激酶受体（ｕＰＡＲ）单抗,分别命名为ＳＺ－ ９８、ＳＺ－ ９９ 、ＳＺ－ １００ 、ＳＺ－ １０１。结论　４ 株单抗均能与ｕＰＡＲ 特异性结合,能与Ｕ９３７ 细胞及经ＰＭＡ作用的Ｋ５６２ 细胞反应。ＳＺ－ １０１ 与国外抗ｕＰＡＲ单抗３９３６ 有相同的ｕＰＡＲ 结合位点;而ＳＺ－９８、ＳＺ－ ９９ 与ＳＺ－ １００ 在ｕＰＡＲ上有不同的结合位点     

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。     

双调蛋白诱导乳腺癌细胞表达尿激酶型纤溶酶原活化物

目的:在人乳腺癌模型上研究双调蛋白与尿激酶型纤溶酶原活化物表达之间的关系.方法:乳腺癌NS2T2A1细胞经双调蛋白反义cDNA质粒转染后经潮霉素B筛选获得表达双调蛋白反义RNA的AR-AS1及AR-AS3两个细胞克隆,转染空载体获得NS2T2A1 V对照细胞,接种至裸鼠皮下形成肿瘤.测定细胞及肿瘤uPA表达水平,并研究uPA与细胞侵袭性之间的关系.结果:AR-AS1及AR-AS3细胞体外及体内uPA表达均被抑制.外源性双调蛋白可刺激对照细胞uPA的表达,并部分恢复AR-AS1及AR-AS3细胞uPA的表达水平.双调蛋白反义cDNA质粒转染及抗uPA抗体均导致乳腺癌细胞体外侵袭性的降低.结论:在乳腺癌模型上,uPA表达与肿瘤细胞的侵袭密切相关.双调蛋白反义RNA表达可有效地抑制uPA的表达,进而抑制肿瘤细胞的侵袭性.     

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。     

尿胰蛋白酶抑制剂Ulinastatin 对lewis 肺癌小鼠肿瘤生长和转移的抑制作用

 目的　探讨尿胰蛋白酶抑制剂(U TI) 在动物模型上抗肿瘤作用。方法　选用尿胰蛋白酶抑制剂乌司他丁(Ulinastatin) , Lewis 肺癌小鼠模型;雄性C57BL/ 6 小鼠40 只,接种lewis 肿瘤细胞,分成生理盐水组(对照组) 、环磷酰胺组(CTX) 、Ulinastatin 2. 5万单位组、Ulinastatin 5 万单位组、Ulinastatin 10万单位组,各8 只,接种后第6 天,开始腹腔给药,记录皮下瘤长短径变化,做生长曲线;接种14 天后处死所有小鼠,统计皮下平均瘤重和肺转移灶个数, 使用流式细胞计分析凋亡率(AR) 增值百分比(SPF) 。结果　皮下瘤重依次为(7. 92 ±2. 52 、0. 66 ±0. 50^＊＊ 、3. 47 ±1. 45^＊ 、3. 08 ±0. 81^＊＊、1. 70 ±1. 05^＊＊) g ,平均肺转移灶依次为( 8. 625 ±1. 407 、1. 125 ±1. 126^＊＊、1. 625 ±1. 302^＊＊ 、1. 00 ±0. 75^＊＊ 、0. 625 ±0. 74^＊＊) 。CTX 组(39. 3 ±4. 8) %^＊ 和Ulinastatin 10 万单位组(40. 2 ±3. 1) %^＊的AR 值明显增加,Ulinastatin 未见SPF 值明显减少。结论　Ulinastatin 对lewis 肺癌小鼠的转移瘤生长和自发性肺转移有抑制作用。     

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.