Clinical significance of urokinase-type plasminogen activator activity in hepatocellular carcinoma

BACKGROUND AND METHODS: The plasminogen activation system plays a crucial role in the process of cancer invasion and metastasis. To evaluate the most effective factor in the invasion, metastasis and prognosis of hepatocellular carcinoma (HCC), we examined urokinase-type plasminogen activator (uPA), plasminogen activator inhibitor (PAI)-1, PAI-2 and uPA activity by enzyme-linked immunosorbent assays (ELISA) in HCC tissues obtained from 46 patients. The results were compared with the patients' clinicopathological features and prognoses. RESULTS: Of the clinicopathological features, only histological portal involvement or intrahepatic metastasis, or both (INV), was significantly correlated to the disease-free survival rates (DFS; P < 0.05). The levels of uPA, PAI-1 and PAI-2 antigens were significantly associated with INV and histological grade. The DFS was not different, however, between cases with uPA, PAI-1 and PAI-2 values above and below the median. The high levels of uPA activity were closely related to INV (P < 0.001), and the activity gradually raised histological grades (P < 0.0001). The DFS was significantly different between patients with uPA activity below and above the median (0.70 ng/mL; P = 0.0092); it was also significantly different between such patients without INV (P < 0.05). CONCLUSIONS: Urokinase-type plasminogen activator activity may be the most sensitive factor affecting HCC invasion in the plasminogen activation system and a strong predictor for the recurrence of HCC. We suggest that cases with uPA activity of more than 0.70 ng/mL should be carefully followed up for possible HCC recurrence.     

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。     

Chromosomal localization of the human urokinase plasminogen activator receptor and plasminogen activator inhibitor type-2 genes: Implications in colorectal cancer

Abstract Activation of the proenzyme of urokinase (uPA) on the surface of cancer cells has been implicated in the initiation of focal proteolytic mechanisms that permit invasion and metastasis by colon cancers. The activity of uPA on the cell surface appears to be a function of the number of uPA-specific receptors (uPAR) and the extent of inhibition of uPA by plasminogen activator inhibitors (PAI). The mapping of the genes coding for uPAR, and for PAI-2, was performed to determine whether their chromosomal localization suggested their involvement in the genetic alterations associated with cancer cell DNA.
This study confirms the localization of the human urokinase plasminogen activator receptor gene to chromosome 19q and, using in situ hybridization, provides a precise localization to chromosome 19q13.2. In addition, our results confirm the previous allocation of the human plasminogen activator inhibitor-2 gene to a location 18q21.3 → 18q21.1, a location that corresponds to the commonest (>70%) somatic deletions found in colorectal carcinomas. The mapping of the uPAR and PAI-2 genes enables the elucidation of their possible involvement in the genetic alterations that determine the invasive and metastatic phenotypes in colorectal cancer.     

A prospective study on the prognostic significance of urokinase-type plasminogen activator levels in breast cancer tissue

Urokinase-type plasminogen activator (u-PA), which cleaves plasminogen to yield plasmin, is a serine protease of fibrinolysis and is presumed to play a key role in extracellular proteolysis and facilitate the migration of cancer cells. This study was conducted prospectively to evaluate the prognostic significance of u-PA antigen level in breast cancer tissues. u-PA concentrations in the cytosol of 226 breast cancer tissues were determined prospectively by enzyme-linked immunosorbent assay using cytosol fractions prepared for steroid hormone assay. The median follow-up period of the patients was 60 months. Various prognostic factors were evaluated by univariate analysis or multivariate analysis using the Cox proportional-hazards method. Patients with primary breast cancer containing high levels of u-PA had a significantly shorter disease-free survival than patients with low levels of u-PA antigens. In multivariate analysis, a high level of u-PA was an independent risk factor for disease-free survival, being independent of age, axillary node status, and estrogen receptor status. Among the major prognostic factors, a high u-PA antigen level, lymph node involvement, and a positive estrogen receptor status were the most important for predicting relapse-free survival (P=0.044, P<0.0001, P=0.0039). This first prospective study confirmed the prognostic significance of the u-PA antigen level in association with other major prognostic factors. The results of our present study suggest that u-PA in breast cancer tissue might be involved in breast cancer invasion and metastasis. Received: 20 November 1996 / Accepted: 9 June 1997     

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.     

Hypofibrinolysis in patients with hypercoagulability: The roles of urokinase and of plasminogen activator inhibitor

The prevalence of abnormalities of fibrinolysis in patients with venous thromboembolism is as yet unknown. Defined abnormalities include congenital dysfunction and deficiency of plasminogen, and probably impaired plasminogen activation secondary to elevated levels of plasminogen activator inhibitor type 1 (PAI-1) or to impaired release of tissue plasminogen activator (tPA). In this preliminary study, we analyzed plasma samples from 21 patients for whom an investigation for possible thrombophilia was requested. Twenty of the patients had venous thromboembolism, and one had arterial thrombosis at an early age. Two patients had deficiency of protein C or protein S, but no other recognized biochemical disturbances related to thrombophilia were identified. Patient samples and plasma from 25 normal controls were assayed for tPA activity, PAI-1 activity, and urokinase (uPA) activity and antigen. tPA activity and antigen were not significantly different in patients than in controls. PAI-1 activity was significantly greater in patients (P < 0.0001). uPA activity was not different in the two groups. However, uPA antigen was significantly reduced in patients compared to controls (P = 0.001). These data suggest that hypofibrinolysis leading to a risk of thrombosis may be caused not only by elevated PAI-1 activity but also by reduced total uPA concentration. © 1993 Wiley-Liss, Inc.     

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     

Stromal expression of urokinase-type plasminogen activator receptor (uPAR) is associated with invasive growth in primary liver cancer

Abstract: Aims/Background: Expression of urokinase-type plasminogen activator receptor (uPAR) was studied in 25 hepatocellular carcinomas (HCCs) and seven cholangiocellular carcinomas (CCCs) by immunohistochemistry. Methods and Results: uPAR was expressed mostly by host cells distributed along the tumour-host interface in all cases of HCC and CCC, and its expression was higher in CCC. These uPAR-positive cells were identified as macrophages by observation of serial sections stained for CD68, a marker for macrophages. Cancer cells were positive for uPAR in only one case of poorly differentiated HCC with sarcomatous changes and in three cases of CCC. Hepatocellular carcinomas were classified into two types: those with a fibrous capsule (expansive type) and those without a fibrous capsule (invasive type). Invasive-type HCCs showed more prominent expression of uPAR by macrophages than expansive HCCs (p<0.001), to approximately the same degree as that of CCC. Extrahepatic metastasis was observed in two of 16 expansive HCCs, five of nine invasive HCCs and six of seven CCCs. Conclusions: Our findings suggest that uPAR expression mainly by macrophages is associated with invasive growth of cancer cells into the surrounding tissue in primary carcinoma of the liver.     

尿激酶型纤溶酶原激活物对糖尿病大鼠肾脏系膜基质的影响

目的 探讨尿激酶型纤溶酶原激活物（uPA）对糖尿病大鼠肾脏系膜基质表达的影响及机制.方法 8周龄健康雄性SD大鼠（体质量150～200 g）20只尾静脉注射链脲佐菌素,成功建立糖尿病大鼠模型后采用数字表法随机分为糖尿病组（n=10）和uPA组（n=10;尾静脉注射2500 U·kg^-1·d^-1 uPA,共4周）.另以10只正常大鼠为对照组.29d后处死大鼠,心脏取血检测血糖、血肌酐水平.过碘酸六胺银染色测定肾小球平均面积、肾小球平均容积和肾小球系膜区面积.免疫组织化学法检测肾脏尿激酶型纤溶酶原激活物受体（uPAR）、纤溶酶原激活物抑制剂-1（PAI-1）和Ⅳ型胶原表达水平.采用方差分析和q检验进行数据统计.结果 与正常对照组比较,糖尿病组大鼠明显出现尿蛋白[（25.4±4.3）mg/24 h vs（5.5±2.1）mg/24 h,q=4.27,P＜0.01],肾小球体积及系膜基质显著增加,肾小球系膜uPAR、PAI-1、Ⅳ型胶原表达显著增加（q值分别为3.63、3.97、4.21,均P＜0.05）.糖尿病大鼠注射uPA后,尿蛋白明显减少[（12.6±5.4）mg/24 h,q=3.45,P＜0.05],肾小球体积、系膜基质异常有所改善（q值分别为4.34、4.27,均P＜0.01）,肾小球系膜PAI-1、Ⅳ型胶原表达明显减少（q值分别为3.98、4.17,均P＜0.05）.结论注射uPA可明显降低糖尿病大鼠肾小球PAI-1蛋白表达,对uPAR表达的影响不大,提示uPA可能通过与uPAR结合、摄取PAI-1并加速其降解,从而调节肾小球系膜细胞及其基质表达,改善糖尿病系膜基质病变.     

肝硬化患者血浆中尿激酶型纤溶酶激活物的检测及其意义

目的 探讨肝硬化患者血浆尿激酶型纤溶酶激活物(uPA)、尿激酶型纤溶酶激活物受体(uPAR)、纤溶酶原激活物抑制剂-1(PAI-1)的变化及其意义。 方法 确诊的72例乙型肝炎后肝硬化患者,Child-pugh分级A级23例(A组),B级29例(B组),C级20例(C组)。6例健康志愿献血者为正常对照组。酶联免疫吸附实验测定血浆uPA、uPAR、PAI-1的变化。并同时检测血透明质酸(HA)、Ⅳ型胶原(C Ⅳ)、Ⅲ型前胶原(PC Ⅲ)、血浆白蛋白、胆红素、凝血酶原时间及其活动度改变。 结果 随着肝硬化的进展,血浆uPA、uPAR、PAI-1逐渐增加,HA、PC Ⅲ也明显增加。Child C组患者血浆uPA、uPAR、PAI-1水平(μg/L)分别为1.88±0.64、4.82±2.02和52.60±16.87,A组分别为1.36±0.43、3.03±1.48和24.09±7.14,B组分别为1.79±0.62、4.80±2.22和41.40±17.52,C组与A、B组比较,t值为2.81～7.38,P值均<0.01。A组血浆uPA与PC Ⅲ呈负相关(r=-0.4785,P<0.05);C组PAI-1与HA呈正相关(r=0.5447,P<0.01)。 结论 肝硬化晚期,虽然血浆uPA、PAI-1增加,但总的效应表现为uPA相对不足,肝基质纤维降解受抑制,血浆uPA、PAI-1与肝硬化发展密切相关。     

Analysis of expressions of components in the plasminogen activator system in high- and low-metastatic human lung cancer cells

Purpose: To determine the expressive patterns of the components of the plasminogen activator system in human large-cell lung carcinoma strains and to analyze the effects of the patterns on tumor invasion and metastasis. Methods: The in vitro and in vivo invasive and metastatic potential of two human large-cell lung carcinoma strains with high (strain 95D) and low (strain 95C) metastatic potential was further confirmed by the Boyden chamber model and nude mice model. After this, the expressions of the components of the plasminogen activator system – including urokinase-type and tissue-type plasminogen activator (uPA and tPA), urokinase receptor (uPAR), and type-1 and type-2 plasminogen activator inhibitor (PAI-1 and PAI-2) in strain 95D and 95C cells – were determined by RT-PCR and immunohistochemical staining. The effects of monoclonal antibodies of uPA, uPAR, and PAI-1 on the invasive potential of strain 95D cell line were also evaluated. Results: Strain 95D cells were found to have a stronger in vitro and in vivo invasive and metastatic potential than strain 95C cells. In the former, the average number of infiltrating cells in the in vitro model in one field of vision (40055) was 73.75 ± 7.42, while in the latter, it was 56.33 ± 6.28 (P < 0.001). Lung metastatic loci were observed in all six nude mice inoculated with 95D cells (6/6), but not in any of the nude mice inoculated with 95C cells (0/6). The high-metastatic strain 95D cells expressed higher uPA and uPAR and lower tPA and PAI-2 than the low-metastatic strain 95C cells. The PAI-1 expressions in both 95D and 95C cells were almost the same. Monoclonal antibodies of uPA and uPAR greatly reduced the invasive potential of strain 95D cells in vitro. Conclusions: These data suggest that the invasive and metastatic potential of human large-cell lung carcinoma cell lines is associated with differential expressions of the components of the plasminogen activator system and that the determination of these components may be used as a marker for judging clinically the possibility of tumor metastasis as well as the prognoses of patients. Received: 31 January 2000 / Accepted: 18 July 2000     

组织型纤溶酶原激活剂及其抑制剂与肺血栓栓塞症

肺血栓栓塞症（PTE）的发病与机体的纤溶和凝血系统功能密切相关。组织型纤溶酶原激活物（t-PA）及其抑制物（PAI-1）因调节机体的纤溶系统而在静脉血栓形成及栓塞性疾病的发病机制中发挥重要作用,因此,本文对t—PA和PAI-1与PTE的关系作如下综述。     

Stimulation of plasminogen activator and inhibitor in the lymphatic endothelium

Chromogenic assays, immunoblotting, and Northern blot hybridization methods were employed to assess the effects of various agonists on the production of tissue plasminogen activator (t-PA) and plasminogen activator inhibitor type 1 (PAI-1) by the lymphatic endothelium (LEC). Fibrin autography showed that plasminogen-dependent fibrinolytic activity occurred at M(r) of 110 kDa, which represents a complex of tPA with PAI-1, and 65- and 55-kDa bands corresponding to tPA and uPA, respectively. The fractionation of lymph collected from ovine lymphatic vessels also produced a prominent lytic band of approximately 110 kDa, suggesting the formation of PA/PAI complexes in lymph. The stimulation of various agonists produced large-scale increases in tPA mRNA, as shown by Northern blot hybridization analyses. The effects of ECGF, histamine, and LPS on the presence of tPA and on enhancing the levels of mRNA reached maximum activity at 4 h and declined to levels below that of controls by 8 h. However, phorbol-treated cells exhibited reduced levels of tPA mRNA at 4 h, but was significantly increased by 8 h. A large-scale increase in PAI-1 mRNA steady-state levels was also stimulated by the agonists used in these studies. Both the 3.4- and 2.4-kb species of PAI-1 mRNA were increased. These observations demonstrated that tPA and PAI-1 are produced and secreted by LEC monolayer cultures and are also present in lymph.     

Effects of octreotide on epidermal growth factor receptor,tissue plasminogen activator,and plasminogen activator inhibitor during intraperitoneal adhesion formation

Background . Intraperitoneal adhesions remain a problem after abdominal surgery. Octreotide has been proved to be able to reduce the number, strength, and extent of fibrous bands at and away from the anastomotic site in an animal model of rats with intestinal resection and reanastomosis. The aim of the present study was to investigate whether epidermal growth factor receptor (EGF-R), tissue plasminogen activator (tPA), and plasminogen activator inhibitor (PAI) are involved in this process. Methods. Laparotomy with intestinal resection and reanastomosis was performed on 60 male Wistar rats. All rats were randomly assigned to five groups: receiving no medication (control; C), normal saline (NS), octreotide solution peritoneal irrigation (Oc), octreotide intramuscular injection (IM), and Oc plus octreotide intramuscular injection (Oc + IM). The concentrations of serum EGF-R, plasma tPA, PAI-1, and PAI-2, and the strength of wound healing were measured. Results. The serum EGF-R concentration showed no significant change from the preoperative level in the C and NS groups 7 and 14 days after the abdominal surgery. However, it decreased significantly on postoperative days 7 and 14 in groups Oc, IM, and Oc + IM (P < 0.05). The plasma tPA concentrations were significantly higher than the preoperative level in all groups of rats on postoperative day 7. The levels were higher in groups Oc, IM, and Oc + IM than in group C or group NS at that time (P < 0.05). On postoperative day 14, the plasma tPA concentrations had returned to the preoperative level in group C and group NS. However, the concentrations in groups Oc, IM, and Oc + IM still remained at a significantly higher level than the concentrations in group C and group NS. The plasma PAI-1 and PAI-2 concentrations showed no significant difference from the preoperative level in group C and group NS on days 7 and 14 after the abdominal surgery. However, the concentrations in groups Oc, IM, and Oc + IM on postoperative days 7 and 14 were markedly lower than those in groups C and NS (P < 0.05). The wound strength was significantly greater on day 14 than on day 7 in all groups. Conclusions. In the rats with octreotide irrigation, the EGF-R level was decreased, the plasma tPA concentration was higher, and the plasma PAI-1 and PAI-2 concentrations were lower when compared with values in group C and group NS rats on days 7 and 14 after surgery. The data suggest that EGF-R, tPA, PAI-1, and PAI-2 are all involved in the mechanism of octreotide's action in reducing adhesion formation. Received: February 25, 2002 / Accepted: November 22, 2002 RID="*" ID="*" Reprint requests to: H.-S. Lai Acknowledgments. This study was supported by a National Science Council Grant (NSC87-2314-B-002-352), and a National Taiwan University Hospital Grant (NTUH. 89S1509)     

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.     

Urokinase type plasminogen activator receptor expression in colorectal neoplasms

Background—The urokinase type plasminogenactivator receptor (uPAR) may play a critical role in cancer invasionand metastasis.
Aims—To study the involvement of uPAR incolorectal carcinogenesis.
Methods—The cellular expression and localisationof uPAR were investigated in colorectal adenomas and invasivecarcinomas by in situ hybridisation, immunohistochemistry, and northernand western blot analyses.
Results—uPAR mRNA expression was found mainly inthe cytoplasm of dysplastic epithelial cells of 30% of adenomas withmild (19%), moderate (21%), and severe (47%) dysplasia, and in that of carcinomatous cells of 85% of invasive carcinomas: Dukes' stages A(72%), B (93%), and C (91%). Some stromal cells in the adjacent neoplastic epithelium were faintly positive. Immunoreactivity for uPARwas detected in dysplastic epithelial cells of 14% of adenomas and incarcinomatous cells of 49% of invasive carcinomas. uPAR mRNA andprotein concentrations were significantly higher in severe than in mildor moderate dysplasia (p<0.05); they were notably higher in Dukes'stage A than in severe dysplasia (p<0.05), and significantly higher inDukes' stage B than in stage A (p<0.05), but those in stage B werenot different from those in stage C or in metastatic colorectalcarcinomas of the liver.
Conclusions—Colorectal adenoma uPAR, expressedessentially in dysplastic epithelial cells, was upregulated withincreasing severity of atypia, and increased notably during thecritical transition from severe dysplasic adenoma to invasivecarcinoma. These findings implicate uPAR expression in the invasive andmetastatic processes of colorectal cancer.

Keywords:urokinase type plasminogen activator receptor; colorectal adenoma; colorectal cancer; adenoma-carcinoma sequence

     

Relationship between matrix metalloproteinase-2 mRNA expression and clinicopathological and urokinase-type plasminogen activator system parameters and prognosis in human gastric cancer

AIM: To investigate the relationship between matrix metalloproteinase-2 (MMP-2) mRNA expression and clinicopathologic and urokinase-type plasminogen activator (uPA) system parameter and prognosis in human gastric cancer. METHODS: Expression of MMP-2 mRNA, uPA, and uPA-R mRNA in tumor tissues and ≥5 cm adjacent normal tissues from 67 cases of gastric cancer was studied using RT-PCR and Northern blot respectively.Survival analyses were done using the Kaplan-Meier method. RESULTS: The expression rates of MMP-2 mRNA,uPA and uPA-R mRNA in tumor tissues (31%,41%,and 51%, respectively) were significantly higher than those in ≥5 cm adjacent tissues (19%, 11%, and 9%; X2=4.59,43.58, and 53.24 respectively, P<0.05,0.0001,and 0.0001, respectively). Expression of MMP-2 mRNA was significantly correlated with lymph node metastasis (metastasis: 61.9%, no metastasis: 39.1%, X2= 7.61, P<0.05),Lauren's classification of diffuse/mixed types:54.2%,intestinal type: 26.3%,X2 = 4.25, P<0.05, expression of uPA and uPA-R mRNA (uPA+: 55.1%, uPA-: 22.2% and uPA-R+: 54.9%, uPA-R-: 18.8%, X2=5.72 and 6.40 respectively, P<0.05).Kaplan-Meier survival analysis of MMP-2 mRNA expression did not show significant difference in all 67 cases, but revealed an association of the expression of MMP-2 mRNA, uPA, and uPA-R mRNA with worse prognosis (P= 0.0083, 0.0160, and 0.0094, respectively). CONCLUSION: MMP-2 may play an important role in the development of invasion and metastasis of gastric cancer.