Expression of urokinase-type plasminogen activator receptor and plasminogen activator inhibitor-1 in gastric cancer

In gastric cancer, the urokinase-type plasminogen activator (uPA) system plays important roles in invasion and metastasis, processes which entail proteolysis and adhesion. Both the urokinasetype plasminogen activator receptor (uPAR) and the plasminogen activator inhibitor-1 (PAI-1) are thought to be important factors in this system. To clarify the relationship between these two factors and gastric cancer invasiveness, we evaluated the expression of uPAR and PAI-1 in 91 cases of gastric cancer by immunohistochemistry and in situ hybridization. Urokinase-type plasminogen activator receptor-mRNA, PAI-1-mRNA, uPAR and PAI-1 protein were diffusely distributed in the cytoplasm of the cancer cells and concentrated at invasive foci. Urokinase-type plasminogen activator receptor protein expression correlated with lymphatic, venous invasion (P<.01) and lymph node metastasis (P<0.05); uPAR-mRNA expression correlated with lymphatic, venous invasion and lymph node metastasis (P<0.05). Plasminogen activator inhibitor-1 protein expression correlated with lymphatic, venous invasion, lymph node metastasis and depth of invasion (P<0.01); PAI-1-mRNA expression was linked to lymphatic, venous invasion (P<0.01), lymph node metastasis and depth of invasion (P<0.05). This suggests that the proteolytic activity of uPAR and the cellular motility of PAI-1 in gastric cancer cells may determine penetration of lymphatic and blood vessels, whereby lymph node metastasis may be promoted and that the promotion of cellular motility by PAI-1 may influence the depth of cancer invasion.     

VEGF、uPA及uPAR与胃癌侵袭和转移的相关性

目的探讨血管内皮生长因子(VEGF)、尿激酶型纤溶酶原激活物(uPA)及其受体(uPAR)与胃癌侵袭、转移的关系及其相关性。方法采用免疫组化SP方法检测198份胃癌组织标本(胃癌组)、60份正常胃黏膜组织标本(对照组)VEGF、uPA、uPAR表达。结果与对照组比较,胃癌组VEGF呈高表达,并与浸润深度、淋巴结转移和临床分期呈正相关,与肿瘤的分化程度呈负相关,P均<0.05;胃癌组uPA和uPAR呈高表达,与病理分级、浸润深度、淋巴转移、临床分期有关,P均<0.05。胃癌组VEGF与uPA表达呈正相关,P<0.01;uPA与uPAR表达呈正相关,P<0.01。结论 VEGF、uPA、uPAR在胃癌发生、发展、侵袭和转移中起促进作用;三者相互促进,相互协调,关系密切。三者均可作为胃癌诊断和预后估计的指标及胃癌治疗的新靶点。     

Invasion and metastasis of hepatocellular carcinoma in relation to urokinase-type plasminogen activator, its receptor and inhibitor

This study was designed to investigate the relationship of urokinase-type plasminogen activator (uPA), uPA receptor (uPAR), and plasminogen activator inhibitor type-1 (PAI-1) to invasion and metastasis of hepatocellular carcinoma (HCC). The expression of uPA, uPAR, and PAI-1 in HCC was determined by immunohistochemistry, Northern blot, and an LCI-D20 nude mouse metastatic model of HCC. The over-expression of uPA, uPAR, and PAI-1 was found in HCC, especially in the patients with portal cancer embolus, tumor invasion, and metastasis. Immunohistochemistry results showed that the rate of positive staining of uPA, uPAR, and PAI-1 were higher in HCC than those in the control groups consisting of cancer-adjacent tissue and normal liver tissue. In the case of HCC invasion, positive uPA and uPAR were seen in 16 and 19 out of 22 patients, respectively (P < 0.01 and P < 0.001, respectively, as compared with the patients without invasion). In those with portal cancer embolus and tumor metastasis, positive uPAR was eight out of eight and six out of six patients. In those with tumor recurrence, positive uPAR was 15 out of 17 patients (P < 0.01 vs no recurrence). In patients who died within 2 years after surgery, positive uPAR was 12 out of 12 patients (P < 0.01 vs survival), and positive PAI-1 was nine out of 12 patients (P < 0.05 vs survival). In those in which uPA, uPAR, and PAI-1 were all positive staining, stronger cancer invasiveness and higher mortality were found (P < 0.05 vs patients with all negative staining). In 30 patients tested with Northern blot analysis, the results were similar to those tested with immunohistochemistry. Higher expression of uPA mRNA and PAI-1 mRNA were detected in tumor tissues and embolus. In the patients with positive signals of uPA mRNA and PAI-1 mRNA, invasive cases were found in seven out of 19 and eight out of 18 patients, respectively, which were significantly higher than those showing negative signals (P < 0.05). In the LCI-D20 nude mouse metastatic model of HCC (MMHCC), PAI-1 activity in plasma and tumor tissue increased with tumor growth, invasion, and metastasis. At an advanced stage of MMHCC, PAI-1 activity rose to 15.4 ± 0.7 Au/ml in plasma and 0.8 ± 0.3 Au/mg in tumor extracts, which was significantly higher than 6.2 ± 1.8 Au/ml in plasma and 0.4 ± 0.1 Au/mg in extracts at an early stage (P < 0.05). PAI-1 activity related to the changes of serum AFP and tumor progress were r=0.9544 and r=0.9648, respectively (P < 0.05). The data suggest that the expression of uPA, uPAR, and PAI-1 is increased in HCC, and related to the invasiveness, metastasis, and prognosis of HCC. Received: 30 September 1999 / Accepted: 10 March 2000     

Inactivation of PTEN is associated with increased angiogenesis and VEGF overexpression in gastric cancer

AIM: To investigate the expression of PTEN/MMAC1/TEP1 and vascular endothelial growth factor (VEGF), their roles in biologic behavior and angiogenesis and their association in gastric cancer.METHODS: Immunohistochemical staining was used to evaluate the expression of PTEN, VEGF and microvascular density (MVD) on paraffin-embedded sections in 70 patients with primary gastric cancer and 24 patients with chronic superficial gastritis (CSG). Expression of PTEN, VEGF and MVD were compared with clinicopathological features of gastric cancer. The relationship between expression of PTEN, VEGF and MVD as well as the relationship between PTEN and VEGF expression in caner cells were investigated. RESULTS: PTEN expression significantly decreased (t= 3.98, P&lt;0.01) whereas both VEGF expression and MVD significant increased (t = 4.29 and 4.41, respectively, both P&lt;0.01) in gastric cancer group compared with CSG group. PTEN expression was significantly down-regulated (t=1.95, P&lt;0.05) whereas VEGF expression (t = 2.37, P&lt;0.05) and MVD (t= 3.28, P&lt;0.01) was significantly up-regulated in advanced gastric cancer compared with early-stage gastric cancer. PTEN expression in gastric cancer showed a negative association with lymph node metastasis (t= 3.91, P&lt;0.01), invasion depth (t= 1.95, P&lt;0.05) and age (t= 4.69, P&lt;0.01). MVD in PTEN-negative gastric cancer was significantly higher than that in PTEN-positive gastric cancer (t=3.69, P&lt;0.01), and there was a negative correlation betweenPTEN expression and MVD (γ=-0.363, P&lt;0.05). VEGF expression was positively associated with invasion depth (especially with serosa invasion, t = 4.69, P&lt;0.01), lymph node metastasis (t= 2.31, P&lt;0.05) and TNM stage (t= 3.04, P&lt;0.01). MVD in VEGF-positive gaslyic cancer was significantly higher than that in VEGF-negative gastric cancer (t=4.62, P&lt;0.01), and there was a positive correlation between VEGF expression of and MVD (y = 0.512, P&lt;0.05). VEGF expression in PTEN-negative gaslyic cancer was significantly stronger than that in PTEN-positive gastric cancer (t=2.61, P&lt;0.05), and there was a significantly negative correlation between the expression of VEGF and PTEN (γ=-0.403, P&lt;0.05).CONCLUSION: Our results imply that inactivation of PTEN gene and over-expression of VEGF contribute to the neovascularization and progression of gastric cancer. PTEN-related angiogenesis might be attributed to its up-regulation of VEGF expression. PTEN and VEGF could be used as the markers reflecting the biologic behaviors of tumor and viable targets in therapeutic approaches to inhibit angiogenesis of gastric cancers.     

Correlative studies on uPA mRNA and uPAR mRNA expression with vascular endothelial growth factor, microvessel density, progression and survival time of patients with gastric cancer

AIM: TO investigate the correlations between the expression of urokinase-type plasminogen activator (uPA) mRNA, uPA receptor (uPAR) mRNA and vascular endothelial growth factor (VEGF) protein and clinicopathologic features, microvessel density (MVD) and survival time. METHODS: In situ hybridization and immuno-histochemistry techniques were used to study the expressions of uPA mRNA, uPAR mRNA, VEGF and CD34 protein in 105 gastric carcinoma specimens. RESULTS: Expressions of uPA mRNA, uPAR mRNA and VEGF protein were observed in 61 (58.1%) cases, 70 (66.7%) cases and 67 (63.8%) cases, respectively. The uPA mRNA and uPAR mRNA positive expression rates in infiltrating-type cases (73.7%, 75.4%), stageⅢ-Ⅳ(72.1%, 75.4%), vessel invasion (63.2%, 69.9%), lymphatic metastasis (67.1%, 74.4%) and distant metastasis (88.1%, 85.7%) were significantly higher than those of the expanding-type (X2= 15.57, P= 0.001; X2=6.91, P=0.046), stageⅠ-Ⅱ(X2 = 19.22, P = 0.001; X2= 16.75, P= 0.001), non-vessel invasion (X2 = 11.92, P = 0.006; X2 = 14.15, P = 0.002), non-lymphatic metastasis (X2 = 28.41, P = 0.001; X2= 22.5, P=0.005) and non-distant metastasis (X2 = 12.32, P= 0.004; X2= 17.42, P = 0.002; X2 = 11.25, P = 0.012; X2 = 18.12, P = 0.002).The VEGF positive expression rates in infiltrating-type cases (75.4%), stageⅢ-Ⅳ(88.5%), vessel invasion (82.9%), lymphatic metastasis (84.3%) and distant metastasis (95.2%) were significantly higher than those of the expanding-type (X2 = 9.61, P = 0.021), stage I-II (X2=16.66, P = 0.001), non-vessel invasion (X2= 29.38, P = 0.001), non-lymphatic metastasis (X2 = 18.68, P = 0.005), and non-distant metastasis (X2= 22.72, P = 0.007; X2 = 21.62, P = 0.004). The mean MVD in the specimens positive for the uPA mRNA, uPAR mRNA and VEGF protein was markedly higher than those with negative expression groups. Moreover, a positive relation between MVD and uPA mRNA (rs = 0.199, P = 0.042), uPAR mRNA (rs = 0.278, P = 0.035), and VEGF (rs = 0.398, P = 0.048) expressions was observed. The mean survival time in cases with positive uPA mRNA, uPAR mRNA and VEGF protein expression or MVD value≥54.9 was significantly shorter than those in cases with negative expression or MVD value < 54.9. CONCLUSION: uPA and uPAR expressions are correlated with enhanced VEGF-induced tumor angiogenesis and may play a role in invasion and nodal metastasis of gastric carcinoma, thereby serving as prognostic markers of gastric cancer.     

大肠癌患者血清中血管内皮生长因子和一氧化氮的检测及其临床意义

目的　研究大肠癌患者血清中血管内皮生长因子 (VEGF)和一氧化氮 (NO)表达水平 ,探讨其在大肠癌中的临床意义。方法　分别采用酶联免疫吸附测定 (ELISA )法和分光光度法检测 5 9例大肠癌患者术前血清中VEGF和NO水平 ,并与 3 0例健康人对照。结果　大肠癌患者血清VEGF和NO表达水平均较健康人明显增高 (P <0 .0 1) ,且随着大肠癌浸润深度增加、有淋巴结转移以及Dukes分期愈晚者而显著增高 (P <0 .0 1)。血清VEGF与NO含量呈明显正相关 (r =0 .817,P <0 .0 1)。结论　VEGF和NO与大肠癌浸润和转移有关 ,术前检测VEGF和NO表达水平有可能作为反映大肠癌恶性进程的重要参考指标     

Deflazacort modulates the fibrinolytic pattern and reduces uPA-dependent chemioinvasion and proliferation in rheumatoid arthritis synoviocytes

OBJECTIVE: Extracellular fibrinolysis, controlled by the cell-associated fibrinolytic system (urokinase plasminogen activator, uPA; uPA receptor, uPAR; plasminogen activator inhibitor type-1, PAI-1), is involved in cartilage damage generation and in rheumatoid arthritis (RA) synovitis. Since steroids reduce the rate of radiological progression of RA, we planned to evaluate in healthy and RA synoviocytes the effects of the steroid deflazacort on uPA, uPAR and PAI-1 expression, and subsequent phenotypic modifications in terms of uPA/uPAR-dependent invasion and proliferation. METHODS: uPA, uPAR and PAI-1 levels were studied by ELISA, RT-PCR (uPAR) and zymography (uPA) in synoviocytes from four RA patients and four healthy controls. Chemoinvasion was assessed by the Boyden chamber invasion assay, using Matrigel as the invasion substrate. Proliferation was evaluated by cell counting. Both invasion and proliferation were measured upon treatment with deflazacort 5 muM with or without parallel stimulation with uPA 500 ng/ml or in the presence of monoclonal anti-uPA and anti-uPAR antibodies. RESULTS: Invasion and proliferation of RA synoviocytes require a proper functional balance of the fibrinolytic system. Both deflazacort and monoclonal antibodies against uPA and uPAR reduced expression and activity of the system, thus inhibiting invasion and proliferation. In RA synoviocytes, deflazacort induced higher PAI-1 and lower uPA and uPAR levels, as well as a decrease in uPA enzymatic activity. The levels of uPAR mRNA were concomitantly reduced, as was uPA-induced chemoinvasion. All these effects were also shown in controls, though to a lesser extent. CONCLUSIONS: Deflazacort might control RA synovial proliferation and invasion by differential modulation of single members of the fibrinolytic system.     

The urokinase plasminogen activator system in cancer: Implications for tumor angiogenesis and metastasis

Substantial evidence exists which implicates the urokinase plasminogen activator system [urokinase plasminogen activator (uPA), urokinase plasminogen activator receptor (uPAR) and plasminogen activator inhibitor-1 (PAI-1)] in the neo-vascularization, invasion and metastasis of many solid tumors. Clinical studies have demonstrated an association between high levels of expression of the components of this system in tumors and poor patient prognosis and outcome. Components of the uPA/uPAR system are differentially expressed or activated on motile cells including invading tumor cells and leukocytes, and migrating endothelial cells. In contrast, there is little or no expression on most normal, quiescent cells. Studies performed in vitro have demonstrated the regulation of the expression of uPA and uPAR by growth and differentiation factors as well as by oncogenes. In this review, we summarize recent findings on the role of the components of the uPA/uPAR system in angiogenesis, invasiveness and tumor metastasis. The activities of this system in endothelial and leukocyte cell biology and the relevance of these activities to angiogenesis and tumor metastasis will be considered. Recent experimental evidence obtained using inhibitors of uPA and uPAR has validated this system as a therapeutic target for the development of anti-angiogenic and anti-metastatic therapeutic agents. These studies, as well as additional therapeutic and diagnostic implications for uPAR targeting, will be discussed. This revised version was published online in June 2006 with corrections to the Cover Date.