Plasminogen activator system, vascular endothelial growth factor, and colorectal cancer progression.

AIMS: To plasminogen activator system (PAS) consists of the plasminogen activators (urokinase (uPA) and tissue-type (tPA) plasminogen activators), the uPA receptor (uPAR), and the plasminogen activator inhibitors (PAI-1 and PAI-2). Plasminogen activators activate plasminogen to plasmin, which can break down extracellular matrix (ECM) components. Vascular endothelial growth factor (VEGF) is a mitogen for endothelial cells and is involved in angiogenesis. VEGF has been shown to upregulate uPA and this may facilitate tumour angiogenesis further. METHODS: PAS components and VEGF were determined by enzyme linked immunosorbent assay (ELISA) in paired colorectal tumour and normal tissue (n = 50) and correlated with pathological staging. RESULTS: uPA, uPAR, PAI-1, and VEGF values were significantly higher in tumour tissue (for example, tumour uPA: median, 2.3 (range, 0.1-6.7) ng/mg protein v normal uPA: median, 0.2 (range, 0-2.6) ng/mg protein). tPA was significantly higher in normal mucosa and there was no difference in PAI-2. uPA, uPAR, PAI-1, and VEGF values significantly correlated with each other and with Dukes's staging (uPA in adenomas: median, 0.42 (range, 0.1-1.2) ng/mg protein; upA in Dukes's B tumours: median, 2.1 (range, 0.4-4.3) ng/mg protein; and uPA in Dukes's D tumours: median, 4.0 (range, 3.7-4.2) ng/mg protein) and lymphatic invasion. In addition PAI-1 also correlated with tumour size and differentiation. CONCLUSION: The involvement of the PAS and VEGF in colorectal cancer appears to be complex. uPA, uPAR, PAI-1, and VEGF were upregulated in tumour tissue and this correlated with Dukes's staging and lymphatic invasion.     

Spitz naevi may express components of the plasminogen activation system

The plasminogen activation (PA) system is involved in the process of invasion and metastasis. Its major components are urokinase (uPA) and tissue-type plasminogen activator (tPA), plasminogen activation inhibitor type 1 and 2 (PAI-1 and PAI-2) and a receptor for urokinase (uPAR). In this study, the expression of plasminogen activation components in Spitz naevi was compared with that in common and dysplastic naevi on the one hand and primary cutaneous melanomas on the other. Spitz naevi had melanocytic positivity for uPA in 0% (0/36), tPA in 30% (6/20), PAI-1 in 10% (3/35), PAI-2 in 40% (8/21) and uPAR in 60% (13/21) of cases. This far exceeded the expression found in common (n = 25) and dysplastic (n = 15) naevi, which only showed melanocytic positivity for PAI-2 (20% and 15% respectively) and in one dysplastic naevus also for uPAR. This was much (for most components significantly) less than the proportion of primary melanomas with tumour cell positivity, which was 30% (11/38) for uPA, 80% (19/24) for tPA, 75% (28/38) for PAI-1, 80% (19/24) for PAI-2 and 80% (19/24) for uPAR. The main findings of this study are that Spitz naevi, firstly, may express plasminogen activator (tPA), inhibitors and the receptor of the PA system, but in a much smaller proportion than cutaneous melanomas; and secondly, do not express urokinase, whereas some of the melanomas do. uPA positivity may therefore be suggestive of melanoma. However, overlapping staining results imply that the PA system has limited value in the differential diagnosis between Spitz naevus and primary melanoma. As serine protease components are expressed, Spitz naevi may use this proteolytic machinery to accomplish matrix degradation, although in a more restricted, possibly transient manner than melanomas.     

Differential localization and expression of urokinase plasminogen activator (uPA), its receptor (uPAR), and its inhibitor (PAI-1) mRNA and protein in endometrial tissue during the menstrual cycle

Normal endometrium is a highly dynamic tissue, which responds to ovarian steroids with cyclic proliferation, differentiation (secretion), and degradation (menstruation). The urokinase plasminogen activator (uPA)-dependent proteolytic cascade as well as ligand activation of the uPA receptor (uPAR) is critically involved in physiological as well as pathophysiological aspects of tissue expansion and remodelling. Cyclic variation and distribution of uPA, uPAR and plasminogen activator inhibitor 1 (PAI-1) mRNA were examined by in situ hybridization, real-time PCR and northern blot in normal endometrium. Their corresponding proteins were localized with immunohistochemistry. uPA mRNA is exclusively expressed by stromal cells, whereas uPA protein is present in both epithelial and stromal cells. Immunostaining for uPA protein is reduced or undetectable at midcycle, thus coinciding with peak concentration of uPA in the uterine fluid. uPAR mRNA is expressed by epithelial cells in the proliferative phase and by stromal cells in the secretory phase. However, epithelial cells stain for uPAR protein throughout the cycle, suggesting that uPAR may detach from stromal cells and then bind to epithelial cells in the secretory phase. PAI-1 mRNA is located in vessel walls. The late secretory phase has greatly increased expression of all three mRNA and their proteins, mainly in pre-decidual cells in the superficial stroma. Discordant localization of the mRNA and proteins suggest that uPA is produced by stromal cells, released and bound to epithelial cells in both the proliferative and secretory phases, whereas uPAR is released from the stroma and bound to epithelial cells in the secretory phase. Also, the present data together with earlier reports suggest that uPA is released from the epithelial cells to the uterine fluid.     

PAI-1 induces cell detachment, downregulates nucleophosmin (B23) and fortilin (TCTP) in LnCAP prostate cancer cells

Plasminogen activator inhibitor (PAI-1) is an anticancer agent that inhibits plasmin driven proteolysis, limiting angiogenesis and metastasis. In low concentrations it could induce cancer cell motility by interacting with urokinase (uPA), its receptor (uPAR), vitronectin and integrins. Active PAI-1 binds to uPA forming a complex with uPAR, while the latent form of PAI-1 does not. PAI-1 is found in both forms in the circulation. It is not clear which form acts as an anticancer agent and how it interacts with malignant cells. To investigate how these forms reduce angiogenesis or metastasis, we have created PAI-1 cysteine mutants in the active conformation (VLHL PAI-1) with an extended half-life that reaches approximately 700 h and its R369A mutant, which has an active conformation but cannot bind to uPA (VLHLNS PAI-1). Both VLHL PAI-1s convert into the latent form when treated with a reducing agent (DTT) that breaks disulfide bridges. Unexpectedly, during routine investigation of LnCAP cell proliferation, we have found that cells detach from the culture vessels regardless of PAI-1 conformation or activity. Further investigation showed that treatment of cancer cells with VLHL PAI-1 downregulated nucleophosmin, while all forms of PAI-1 downregulated fortilin. These two proteins are implicated in important cellular processes (cell growth, cell cycle, malignant transformation). This suggests that PAI-1, in addition to its well-known anticancer properties, plays an important role in cell signaling. We hope that by exploring PAI-1's structure and function we might be able to understand and separate the different effects of PAI-1 on cancer cells and develop more effective therapeutic strategies in cancer treatment.     

Induction of the plasminogen activator system by mechanical stimulation of human bronchial epithelial cells

Mechanical stimulation of the airway epithelium, as would occur during bronchoconstriction, is a potent stimulus and can activate profibrotic pathways. We used DNA microarray technology to examine gene expression in compressed normal human bronchial epithelial cells (NHBE). Compressive stress applied continuously over an 8-h period to NHBE cells led to the upregulation of several families of genes, including a family of plasminogen-related genes that were previously not known to be regulated in this system. Real-time PCR demonstrated a peak increase in gene expression of 8.0-fold for urokinase plasminogen activator (uPA), 16.2-fold for urokinase plasminogen activator receptor (uPAR), 4.2-fold for plasminogen activator inhibitor-1 (PAI-1), and 3.9-fold for tissue plasminogen activator (tPA). Compressive stress also increased uPA protein levels in the cell lysates (112.0 versus 82.0 ng/ml, P = 0.0004), and increased uPA (4.7 versus 3.3 ng/ml, P = 0.02), uPAR (1.3 versus 0.86 ng/ml, P = 0.007), and PAI-1 (50 versus 36 ng/ml, P = 0.006) protein levels in cell culture media. Functional studies demonstrated increased urokinase-dependent plasmin generation in compression-stimulated cells (0.0090 versus 0.0033 OD/min, P = 0.03). In addition, compression led to increased activation of matrix metalloproteinase (MMP)-9 and MMP-2 in a urokinase-dependent manner. In postmortem human lung tissue, we observed an increase in epithelial uPA and uPAR immunostaining in the airways of two patients who died in status asthmaticus compared with minimal immunoreactivity noted in airways from seven lung donors without asthma. Together these observations suggest an integrated response of airway epithelial cells to mechanical stimulation, acting through the plasminogen-activating system to modify the airway microenvironment.     

In situ localization of mRNA for the fibrinolytic factors uPA, PAI-1 and uPAR in endometriotic and endometrial tissue

Endometriotic tissue grows invasively. The plasminogen-activating system is suggested to participate in degradation of extracellular matrix (ECM) and modulation of cell adhesion and migration. We have previously demonstrated elevated levels of the fibrinolytic factors urokinase plasminogen activator (uPA) and plasminogen activator inhibitor (PAI-1) in endometriotic tissue and endometrium from women with endometriosis. The aim of the present study was to localize the uPA, PAI-1 and urokinase plasminogen activator receptor (uPAR) mRNA in endometriotic tissue and in endometrium both from women with and without endometriosis. With in situ hybridization, we found that uPA mRNA seems to be up-regulated in endometriotic glands and endometrial stroma as well as PAI-1 mRNA in endometriotic and endometrial stroma from women with endometriosis. uPAR mRNA likewise appears to be up-regulated in both glands and stroma in endometriotic tissue and in endometrial glands from patients compared to endometrial glands and stroma from healthy women. These differences might be important for menstrual shedding and adherence of endometrial fragments to peritoneal lining in women developing endometriosis and for the invasive growth of endometriotic tissue.     

Characterization of human prostate mast cells and their increase in periprostatic vein thrombosis.

Recent data suggest that mast cells (MCs) and their products are involved in the pathophysiology of thrombosis. In the present study, we analyzed the number, distribution, and phenotype of prostate MCs and periprostatic MCs in patients with unilateral periprostatic vein thrombosis (PVT) by immunohistochemical analysis and electron microscopy. MCs reacted with monoclonal antibodies to tryptase, chymase, and c-kit/CD117 and stained positively for tissue-type plasminogen activator (tPA) and urokinase receptor (uPAR/CD87) but did not express detectable urokinase (uPA) or plasminogen activator inhibitors (PAI-1, PAI-2). We found an increase in the mean +/- SEM number of MCs in PVT compared with control (PVT, 14.36 +/- 1.57 vs control, 5.23 +/- 0.57/mm2). The majority of MCs accumulated in the adventitia of thrombosed veins and showed a decrease in chymase expression. As MCs increase in number in PVT and express a profibrinolytic phenotype, we hypothesize that MC-derived molecules have a role in endogenous fibrinolysis.     

Immunohistochemical expression of uPA, uPAR, and PAI-1 in breast carcinoma. Fibroblastic expression has strong associations with tumor pathology

The urokinase-type plasminogen activator (uPA) system has been implicated in tumor spread. We have used immunohistochemistry to examine three components of this system, ie, uPA, uPA receptor (uPAR), and plasminogen activator inhibitor-1 (PAI-1), in a pilot study on 142 cases of breast carcinoma. We wished to determine whether there were any relationships between expression of the proteins in either tumor cells or fibroblasts and clinical and pathological features. Strong uPA expression in each cell type was significantly related to high tumor grade (P = 0.013 and 0.008, respectively), and was more common in invasive than in in situ carcinomas (P < 0.0001). Fibroblastic expression of uPAR was only related to the presence of invasion (P < 0.0001). Strong PAI-1 expression in both cell types was seen in high-grade tumors (tumor cells, P = 0.012; fibroblasts, P < 0.001), but only fibroblastic expression was related to the presence of invasion (P = 0.042). Fibroblastic expression of both uPA and uPAR were positively correlated with tumor size. Although patients with strong fibroblastic expression of uPA showed a tendency toward a shorter time to relapse, none of the plasminogen activator proteins were significantly associated with relapse-free survival. These results suggest that strong expression of uPA, uPAR, and PAI-1 in fibroblasts rather than in tumor cells have the most impact on the clinical behavior of breast cancer. Larger prospective studies are needed to confirm these findings.     

Expression of urokinase-type plasminogen activator, urokinase-type plasminogen activator receptor, and plasminogen activator inhibitor-1 and -2 in hepatocellular carcinoma

It has become more and more clear in recent decades that the plasminogen activation system, which includes urokinase-type plasminogen activator (uPA), urokinase-type plasminogen activator receptor (uPAR), plasminogen activator inhibitor (PAI)-1 and PAI-2, plays a very important role in the aggressiveness of cancer. Using immunohistochemistry and enzyme-linked immunosorbent assay (ELISA), the expression of these four components of the uPA system was analyzed in 19 cases of hepatocellular carcinoma (HCC) and 18 cases of the adjacent non-cancer tissues which all had chronic active hepatitis with liver fibrosis or liver cirrhosis. Four cases of normal liver tissues, as controls for immunohistochemical stains, were obtained from the hepatectomized liver of patients with metastatic cancer in the liver. The positive rates of uPA, uPAR, PAI-1 and PAI-2 for immunohistochemical stains in cancer tissues were 78.9, 68.4, 57.9 and 31.6%, respectively. Positive signals were mainly distributed in the cytoplasm of the cancer and in stromal cells. Moreover, the strong stains were chiefly located in the invasive front of the cancer cells. No specific stain was detected in four cases of normal liver tissues. In ELISA, there were significant differences between cancer and non-cancer tissues in concentration of uPA, uPAR and PAI-1 (P < 0.0003, 0.0024 and 0.01, respectively), but there was no significant difference in that of PAI-2 (P = 0.37). These results suggest that uPA, uPAR and PAI-1 are related to invasion of HCC.     

大鼠肝纤维化过程中4种肝脏细胞对纤溶系统的调节

目的:探讨在大鼠肝纤维化发展过程中,肝细胞、肝星状细胞(HSCs)、Kupffer细胞和内皮细胞(ECs)对纤溶系统的调节作用。方法:采用1周2次皮下注射50%CCl4、持续12周的方法制备大鼠慢性肝纤维化模型;将肝纤维化不同时期的4种肝脏细胞进行分离;采用Northern印迹法及Western印迹法分别测定大鼠各类肝脏细胞中尿激酶型纤溶酶原激活物(uPA)、以及它的抑制物(PAI-1)和受体(uPAR)的mRNA和蛋白表达。结果:Northern印迹法及Western印迹法分析均显示,在大鼠肝纤维化过程中,HSCs和ECs均为PAI-1、uPAR的主要产生细胞,相比之下,HSCs产生更多。结论:在大鼠肝纤维化发生发展过程中,HSCs和ECs对纤溶系统成分的产生起着重要的调节作用,而HSCs则是PAI-1、uPAR最主要的产生细胞。     

Time-dependent biological differences in molecular markers of high-grade urothelial cancer over 7 decades (ras proteins, pTEN, uPAR, PAI-1 and MMP-9)

The aim of this study was to evaluate changes and correlations between various molecular markers related to growth regulation and invasiveness in urothelial carcinomas in samples collected from 1932 to 2004. Paraffin-embedded autopsy/biopsy tissues from 144 patients were stained with antibodies against H–K–N ras proteins, pTEN protein, urokinase plasminogen activator receptor (uPAR), plasminogen activator inhibitor-1 (PAI-1) and matrix metalloproteinase-9 (MMP-9) and analyzed by in situ hybridization. Statistical analysis was performed by SPSS using cross tabulation and logistic regression. While the presence of K-ras, N-ras, PAI-1, and loss of pTEN increased over the last few decades, uPAR expression decreased during the same period. The increase in K-ras expression associated positively with the increase in expression of the other two ras proteins, H-ras and N-ras, and the loss of pTEN. A strong positive correlation was also observed between PAI-1 and uPAR, PAI-1 and previously detected markers, EGFR (epidermal growth factor receptor) and p53. Presence of uPAR was found to be positively associated with p16 expression. Multivariate analysis with clinical parameters revealed a positive correlation between PAI-1 expression and tumour grade, CkHMW (high molecular weight cytokeratin) and tumour grade, CkHMW and metastasis, EGFR and metastasis. mRNA could be detected in samples from the last 50?years while older samples were negative, indicating its complete degradation during longer storage. In conclusion, increased accumulation of K-ras, N-ras, and PAI-1 together with loss of pTEN in bladder carcinomas of grades II and III seems to be more dominant in recent times, suggesting an altered malignant potential in these neoplasms.     

Influence of preoperative core biopsies on uPA/PAI-1 expression in breast cancer tissue

The urokinase-type plasminogen activator (uPA) and the plasminogen activator inhibitor-1 (PAI-1) are involved in tumor invasion and metastasis as well as wound healing and inflammation. We investigated the impact of tissue injury by preoperative sampling on the level of uPA/PAI-1 in paraffin tissue of 55 breast cancer cases by immunohistochemistry. The tumor area surrounding the biopsy channel was compared with distant intact tumor tissue. uPA and PAI-1 were constantly expressed by the tumor cells. Fibroblastic expression was higher in the tumor area surrounding the biopsy channel than in intact tissue with 47 vs 29 positive cases for uPA (p<0.001) and 35 vs 25 positive cases for PAI-1 (p=0.055). A decrease in fibroblastic enzyme expression from the biopsy area to the intact tumor tissue was seen in 21 cases for uPA and 16 cases for PAI-1. This difference was most evident in cases with an interval of 6 days and longer between biopsy and surgery. In conclusion, fibroblastic inflammatory reaction around the biopsy channel affects stromal uPA and PAI-1 expression, which possibly leads to falsely increased enzyme levels in ELISA. Tissue specimen for ELISA analysis should not be taken from the tumor area around the biopsy channel in the resection specimen.     

Discrimination of different forms of the murine urokinase plasminogen activator receptor on the cell surface using monoclonal antibodies

The urokinase plasminogen activator receptor (uPAR) is a versatile three-domain GPI-anchored protein, which binds urokinase plasminogen activator (uPA) and thereby focalises plasminogen activation on the cell surface. Generation of a proteolytic potential is essential in both normal physiological and pathological extracellular tissue remodelling processes. uPA can also cleave uPAR, resulting in liberation of the amino-terminal domain I, which encompasses binding sites for both uPA and the adhesion molecule, vitronectin. In order to localise the different uPAR forms on the plasma membrane of murine monocyte macrophage-like P388D.1 cells, we have now generated and characterised two high-affinity murine mAbs, mR3 and mR4, raised against murine uPAR. mR3 was found to recognise an epitope located in domain I of uPAR. Surface plasmon resonance analyses and cell binding studies revealed that this mAb was able to bind preformed complexes of murine pro-uPA and murine uPAR. In contrast, mR4 recognises domains II-III in uPAR and does not bind preformed pro-uPA-uPAR complexes in similar analyses. Immunofluorescence microscopy of P388D.1 cells revealed that mR3 stained the cells equally well in the presence or absence of saturation with the amino-terminal fragment of uPA, ATF. However, the signal intensity obtained using another uPAR domain I specific mAb, mR1, was significantly reduced upon ATF saturation. Furthermore, when adding ATF, mR4 selectively stained the cleaved receptor. Applying these newly generated mAbs, we additionally demonstrated that cleaved and intact uPAR was evenly distributed on the surface of these cells.     

uPA系统与神经胶质瘤局部侵袭

uPA系统包括尿激酶型纤溶酶原激活物（urokinase plasminogen activator, uPA）、 尿激酶型纤溶酶原激活物受体（urokinase plasminogen activation receptor, uPAR）和纤溶酶原激活物抑制剂(plasminogen activator inhibitor, PAI),它们参与了多种人类恶性肿瘤的局部侵袭和转移,是目前肿瘤治疗重要的分子靶点。uPA能激活纤溶酶原降解细胞外基质与基底膜,uPAR则能显著提升uPA的激活纤溶酶原的功能,两者结合能够增强肿瘤的侵袭性与转移能力。PAI主要通过促进血管内皮生长因子（vascular endothelial growth factor,VEGF）的表达,促进新生血管的形成,从而促进肿瘤的局部侵袭,但PAI又可通过抑制uPA-uPAR复合体的生物学活性来抑制肿瘤的局部侵袭。神经胶质瘤是最常见的颅内肿瘤,很少转移到颅外,局部侵袭是其预后不良的主要原因。近年来发现uPA系统的表达水平与神经胶质瘤的恶性程度呈正相关。本文综述了uPA系统对神经胶质瘤局部侵袭的影响及其在治疗中的意义。     

The plasminogen activator inhibitor "paradox" in cancer

Proteolysis in general and specifically the plasminogen activating system regulated by urokinase (uPA) its specific receptor, the GPI membrane anchored urokinase receptor (uPAR) and the specific plasminogen activator inhibitor 1 (PAI-1) plays a major role in tumorigenesis, tumor progression, tumor invasion and metastasis formation. This is exemplified by a body of published work showing a positive correlation between the expression of uPA or uPAR in several tumors and their malignancy. It is generally assumed that such a "pro-malignant" effect of the uPA-uPAR system is mediated by increased local proteolysis thus favoring tumor invasion, by a pro-angiogenic effect of this system and also by uPA-uPAR signaling towards the tumor thereby shifting the tumor phenotype to a more "malignant" one. However, when tumor patients are analyzed for long term survival, those with high levels of the inhibitor of the system, PAI-1 have a much worse prognosis than those with lower PAI-1 levels. This indicates that increased overall proteolysis alone cannot be made responsible for the adverse effects of the plasminogen activating system in tumors. Moreover, it becomes increasingly evident that components of the fibrinolytic system secreted by the tumor cells themselves are not solely responsible for a correlation between the plasminogen activating system and tumor malignancy; components of the plasminogen activating system secreted by stroma cells or cells of the immune system such as macrophages contribute also to the impact of fibrinolysis on malignancy. This review summarizes the evidence for the role of plasminogen activator inhibitor-1 in mediating the malignant phenotype and possible mechanism thereby trying to explain the "PAI-1 paradox in cancer" on a molecular level.     

胃癌中uPA、PAI-1表达及其与血管生成的关系

目的 观察胃癌组织中uPA、PAI-1mRNA及蛋白的表达，并探讨它们与肿瘤分化、血管生成及临床病理因素之间的关系。方法 用原位杂交及免疫组化S-P法检测110例胃癌组织中uPA、PAI-1的表达，根据CD34阳性的血管内皮细胞计数肿瘤组织微血管密度（MVD）。结果 （1）胃癌组织中uPA mRNA和蛋白、PAI-1 mRNA和蛋白阳性表达定位于胞质；uPA的表达随分化程度的降低有逐渐升高的趋势，PAI-1的表达随分化程度的降低有逐渐降低的趋势。（2）110例uPA mRNA及蛋白表达阳性组MVD值显著高于阴性组，差异均具有显著性（P值均＜0．05）。（3）uPA mRNA及蛋白的表达与临床分期呈正相关（P＜0．05），PAI-1的表达与临床分期和淋巴结转移无相关性。（4）uPA mRNA／蛋白与PAI-1 mRNA／蛋白的表达无相关性。结论uPA与促进胃癌的血管生成密切相关，阻断uPA的分泌和作用途径有望对胃癌浸润转移起抑制作用；胃癌组织中PAI-1可能担当重要的调节剂或者是肿瘤细胞防止自身降解的保护剂而不是这个系统的单纯抑制剂。     

Dysregulation of matrix metalloproteinases and their tissue inhibitors is related to abnormality of left ventricular geometry and function in streptozotocin-induced diabetic minipigs

This study aimed to characterize matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in relation to changes in left ventricle (LV) geometry and function in a porcine model with streptozotocin (STZ)-induced diabetes. In 15 Chinese Guizhou minipigs with STZ-induced diabetes (diabetic group) and 15 age-matched normal controls (control group), Doppler tissue imaging was performed at 6 months of diabetes. Serum MMP-2, -9, TIMP-1, -4 and B-type natriuretic peptide (BNP) were determined. Expression of MMPs, TIMPs, urokinase type-plasminogen activator (uPA), its receptor (uPAR) and plasminogen activator inhibitor-1 (PAI-1) in aortic intima and LV myocardium was evaluated, with gelatinolytic activities of tissue MMP-2, -9 accessed by zymography. Left ventricle end-diastolic septum thickness (P < 0.05) and mass (P < 0.05) were increased, whereas peak systolic mitral annulus velocity (Sm, P < 0.001), LV systolic (P = 0.01) and diastolic strain (P < 0.001) were significantly decreased in diabetic group than in controls. Diabetic group showed higher expression of TIMP-1, -4 in aortic intima and LV myocardium (P < 0.01 or P < 0.05), with increased collagen content and elevated serum BNP level (P = 0.004) and lower gelatinolytic activities of tissue MMP-2, -9 (all P < 0.05). Semi-quantitative RT-PCR of those diabetic tissues revealed elevated mRNA levels of major TIMPs, uPA, uPAR and PAI-1. Reduction of serum MMP-2 and -9 levels was observed in diabetic group vs. control group (both P < 0.05). This study features elevated levels of TIMP-1, -4, uPA, uPAR and PAI-1, and decreased activities of MMP-2, -9 in aorta and myocardium in STZ-induced diabetic minipigs, indicating that MMP-TIMP dysregulation is associated with LV hypertrophy, cardiac dysfunction and increased cardiovascular fibrosis in diabetes.     

uPAR与肿瘤的研究新进展

尿激酶型纤溶酶原激活物受体(urokinase plasminogen activator receptor,uPAR)是一个糖基磷脂酰肌醇锚定的蛋白质,高亲和力结合并激活尿激酶型纤溶酶原激活物(urokinase plasminogen activator,uPA),由此调节细胞表面蛋白水解活性。uPAR在几乎所有人类肿瘤中高表达,其高表达与增强肿瘤增殖、迁移、侵袭有关。本文对uPAR增强肿瘤趋向性、诱导上皮-间质转变与促进胞葬作用等新功能以及靶向uPAR治疗进展进行综述。     

Angiogenic cytokines and growth factors in systemic sclerosis

Systemic sclerosis is an autoimmune connective tissue disorder characterized by a widespread microangiopathy, autoimmunity and fibrosis of the skin and of various internal organs. Microangiopathy is characterized by a reduced capillary density and an irregular chaotic architecture that lead to chronic tissue hypoxia. Despite the hypoxic conditions, there is no evidence for a sufficient compensative angiogenesis in SSc. Furthermore, vasculogenesis is also impaired. An imbalance between angiogenic and angiostatic factors might explain the pathogenetic mechanisms of SSc vasculopathy. As far as angiogenic factors are concerned, within the most important are vascular endothelial growth factor (VEGF) and its receptors, platelet derived growth factor (PDGF), transforming growth factor beta (TGF-β), fibroblast growth factor -2 (FGF-2), angiopoietin 1 (Ang-1), stromal cell-derived factor 1 (SDF-1/CXCL12), endothelin-1 (ET-1), monocyte chemoattractant protein -1 (MCP-1), urokinase type plasminogen activator receptors (uPAR) and kallikreins, vascular adhesion molecules. On the other hand, angiostatic factors include: endostatin, angiostatin, thrombospodin-1 (TSP-1), angiopoietin 2 (Ang-2). Our knowledge concerning the dysregulation of angiogenic homeostasis is largely incomplete and needs further research, for the future.     

Expression of urokinase-type plasminogen activator,its receptor,and its inhibitor in gastric adenocarcinoma tissues.

The plasminogen and plasmin system, which is mainly regulated by urokinase-type plasminogen activator (uPA), its receptor (uPAR) and its inhibitor (PAI-1), is generally believed to play a role in cancer invasion and metastasis. This study was conducted to investigate the role of uPA, uPAR and PAI-1 in the invasion and metastasis of gastric adenocarcinoma. The expression of mRNAs for uPA and PAI-1 was determined by Northern blot analysis in nine primary gastric cancer tissues, nine paired metastatic lymph nodes and normal gastric mucosa. The mRNA of uPA was not or faintly detected in normal mucosa, while the expression was increased in both primary gastric cancer tissues and metastatic lymph nodes to a similar degree. The mRNA expression for PAI-1 in the gastric cancer tissues was not different from that in the paired metastatic lymph nodes and normal mucosae. uPAR was determined by immunohistochemical staining, demonstrating that five (56%) and six (67%) out of nine primary gastric cancer tissues and nine paired metastatic lymph nodes were positive, respectively and the intensity was stronger in metastatic lymph nodes. The results support the concept that most gastric cancer cells may have an innately moderate level of uPA and uPAR, and that increase of uPAR expression can be considered to be closely associated with cancer invasion and metastasis.