5328

PLAU

plasminogen activator, urokinase;PLAU;plasminogen activator, urokinase

U-plasminogen activator|plasminogen activator, urinary|urokinase-type plasminogen activator

10q22.2

protein-coding

Emerging evidence suggests the potential involvement of altered regulation of miRNAs in the pathogenesis of cancers, and these miRNAs are thought to be functional as tumor suppressors or oncogenes. Using miRNA arrays, we identified an miRNA differentially expressed between the MDA-MB-231 cell line and its highly metastatic variant. A bioinformatics search revealed a potential target site for miR-193b within the 3'UTR of uPA. Ectopic expression of miR-193b repressed the expression of sensor constructs harboring the 3'UTR of uPA in breast cancer cell lines. Anti-miR-193b treatment led to an increase of uPA protein and increased cell invasion in MDA-MB-231 cells. In contrast, overexpression of miR-193b significantly reduced uPA protein amounts and inhibited cell invasion in MDA-MB-231 and MDA-MB-435 cells. In an immunodeficient mouse model, miR-193b significantly inhibited the growth and dissemination of xenograft tumors. Immunohistochemical staining and real-time PCR assays showed that miR-193b was a negative regulator of the uPA gene in primary breast tumors. Our research reveals that miR-193b is closely associated with clinical metastasis and identifies miR-193b potentially targets uPA transcripts. Perturbation of the miRNA-mRNA pairing may have important roles in the initiation and development of breast cancer.

AIM: To investigate the role of urokinase plasminogen activator (uPA) in cholangiocarcinoma (CCA) invasion and its correlation with clinicopathological parameters. METHODS: uPA expression in CCA tissue was determined by immunohistochemistry. The level of uPA from two CCA cell lines (HuCCA-1 and KKU-M213) and a non-cancer immortalized cholangiocyte cell line (H69) was monitored by plasminogen-gelatin zymography and western blotting, whereas that of plasminogen activator inhibitor type 1 (PAI-1) protein and uPA receptor (uPAR) mRNA was monitored by western blotting and quantitative real-time reverse transcriptase polymerase chain reaction, respectively. Two independent methods were employed to suppress uPA function: a synthetic uPA inhibitor (B428) and silencing of uPA gene expression using siRNA. In vitro invasion of the uPA-disrupted cells was assessed by Matrigel-coated Transwell assay. RESULTS: The immunohistochemical study showed that 75.3% (131/174) of CCA tissues expressed uPA. High uPA expression was correlated with lymphatic invasion and metastasis of CCA patients. Plasminogen-gelatin zymography of the conditioned media and cell-surface eluates showed that both CCA cell lines, but not H69, expressed both secreted and membrane-bound forms of uPA. Although the two CCA cell lines, HuCCA-1 and KKU-M213, expressed a relatively high level of uPA and uPAR, the latter exhibited a much lower degree of in vitro invasiveness, correlating with a high expression of PAI-1 in the latter, but not in the former. Suppressing uPA function with a specific uPA inhibitor, B428, or with siRNA against uPA reduced in vitro invasiveness of KKU-M213 cells, demonstrating the requirement for uPA in the invasiveness of CCA cells. Therefore, our in vivo and in vitro studies suggest that uPA is an important requirement for the invasion process of CCA. CONCLUSION: uPA expression correlates with lymphatic invasion and metastasis in vivo and is required for CCA cell invasion in vitro, suggesting its potential as a therapeutic target.

PURPOSE: Laparoscopic surgery in the treatment of colon carcinoma causes pH value alterations as well as changes in fibrinolytic activity. This results in enhanced proliferation of colon carcinoma cells in vitro and also in enhanced growth of liver metastasis when compared to isobaric (gasless) laparoscopy in vivo. So far, the direct influence of CO(2) pneumoperitoneum on the invasiveness and metastatic capabilities of colon cancer cells remains unclear. We therefore evaluated transcripts of the uPA system. METHODS: The influence of CO(2) pneumoperitoneum on the gene expression of plasminogen activator inhibitor-1 (PAI-1), urokinase-type plasminogen activator (uPA), and tissue-type plasminogen activator (tPA) was investigated in colon carcinoma cell lines (HT116, SW48, and WiDr) and mesothelial cells employing a pneumoperitoneum chamber in vitro. Quantitative gene expression data were collected using real-time RT-PCR and statistical analysis was performed by means of analysis of variance and Bonferroni correction. RESULTS: The expression of uPA and PAI-1 was increased in colon carcinoma cell lines when cultivated at pH 6.1, a value corresponding to intraabdominal pH values during CO(2) insufflation. Elevated PAI-1 mRNA levels were also observed when CO(2) was simultaneously applied with a pressure of 10 mmHg. In contrast, there were no significant changes in mesothelial cells in the investigated parameter. CONCLUSION: The conditions of CO(2) pneumoperitoneum cause changes in the expression of genes controlling the fibrinolytic activity. The increase of PAI-1 and uPA can contribute to the enhancement of metastasis and invasive potential of tumour cells. Therefore, changes in the conditions of laparoscopy may well optimise laparoscopic therapy in colon cancer.

BACKGROUND: It has been demonstrated that urokinase-type plasminogen activator (uPA) is involved in tumor cell metastasis by degrading the extracellular matrix. However, there is little direct evidence of clinical uPA system expression in peritoneal metastatic tissues of gastric cancer. The objective of this study was to investigate uPA system expression in peritoneal tissues of peritoneal and nonperitoneal metastasis patients, and to explore the diagnostic value of the uPA system. METHODS: expressions of uPA, uPAR, and PAI-1 were measured by semi-quantitative RT-PCR and ELISA. uPA activity was detected using a uPA activity kit. RESULTS: There was no significant difference in uPA, uPAR, and PAI-1 expression in two types of peritoneal tissue in seven patients with peritoneal metastasis. However, uPA, uPAR, and PAI-1 expressions in peritoneal metastatic lesions were significantly higher than those in normal peritoneal tissues of 24 nonperitoneal metastasis patients (P <0.05). Moreover, no statistical discrepancy of uPA activity was observed in various different tissues. CONCLUSIONS: The expression of the uPA system positively correlates with peritoneal metastasis of gastric cancer. This expression difference in peritoneal or nonperitoneal metastasis patients may provide a reference for diagnosis of peritoneal metastasis.

Autotaxin, a lysophospholipase D producing lysophosphatidic acid, augments invasive and metastatic potential of tumor cells. Current investigations have focused on understanding the molecular mechanisms by which autotaxin regulates the expression of a major mediator of tumor invasion and metastasis, urokinase-type plasminogen activator (uPA) in human A2058 melanoma cells. Autotaxin induced uPA expression in a dose-dependent manner that was inhibited by pharmacological inhibitors for Gi (pertussis toxin), phosphoinositide 3-kinase (PI3K, LY294002), Akt inhibitor (AktI), proteosome activity and IkappaB phosphorylation (pyrrolidine dithiocarbamate), and by a dominant negative mutant (DN) of Akt. Autotaxin phosphorylated Akt and induced the translocation of nuclear [corrected] factor-kappaB (NF-kappaB) to the nucleus that were inhibited by AktI or by overexpressing DN-Akt. Consistently, green fluorescence protein-tagged p65 of NF-kappaB accumulated in the nucleus by autotaxin that was abrogated when the cells were transfected with DN-Akt. Moreover, autotaxin increased the DNA binding ability of NF-kappaB and promoter activity of uPA. Collectively, these data strongly suggest autotaxin induces uPA expression via the Gi-PI3K-Akt-NF-kappaB signaling pathway that might be critical for autotaxin-induced tumor cell invasion and metastasis.

The fibrinolytic system, more appropriately referred to as the plasminogen activator system, controls not only the intravascular fibrin deposition but also participates in a wide variety of physiologic and pathologic processes. In cancer, the components of this system are involved in tumor growth, invasion and metastasis, through their effect on angiogenesis and cell migration. These components are found in most tumors and their expression signifies not only their function but also carries a prognostic value. Their expression is in turn modulated by cytokines and growth factors, many of which are up-regulated in cancer. Though both plasminogen activators, tPA and uPA, are expressed in tumor cells, uPA with its receptor (uPAR) is mostly involved in cellular functions, while tPA with its receptor annexin II on endothelial surface regulates intravascular fibrin deposition. Among the inhibitors of fibrinolysis, PAI-1 is a major player in the pathogenesis of many vascular diseases as well as in cancer. Therapeutic intervention, either using plasminogen activators or use of experimental inhibitor agents against PAI-1, has shown encouraging results in experimental tumors but not verified clinically. Information provided in this brief review is aimed to promote greater interest in the role of the plasminogen activator system in cancer.

PURPOSE: Interaction between tumor cells and surrounding stromal fibroblast (SF) plays a critical role in tumor growth and invasion. The aim of the study is to determine the role of SF in regulating the invasive behaviors of pancreatic cancer by evaluating the mode of SF activating the urokinase plasminogen activator (uPA)-plasmin-matrix metalloproteinase (MMP)-2 cascade. EXPERIMENTAL DESIGN: The expression patterns of uPA, MMP-2, and uPA receptor (uPAR) in human metastatic pancreatic cancer were analyzed by immunohistochemistry and the roles of SF in activation of the uPA-plasmin-MMP-2 cascade were evaluated by coculturing pancreatic cancer cell lines with SF. RESULTS: uPA expression and fibroblastic uPAR expression were correlated with liver metastasis of human pancreatic cancer. MMP-2 rather than MMP-9 was activated in the metastatic pancreatic cancer. In the in vitro culture system, the coculture of peritumor fibroblasts with metastatic pancreatic cancer BxPc3 cells resulted in activation of MMP-2 and up-regulation of uPAR expression. In this coculture system, the uPA-plasminogen cascade was involved in MMP-2 activation. This activation required a direct interaction between SF and cancer cells. In the coculture system, intergrin alpha(6)beta(1) expression was increased in BxPc3 cells, and blocking the function of integrin alpha(6)beta(1) decreased the activation of uPA and MMP-2. This suggests that interaction between integrins of cancer cells and the uPARs of the SF might be involved in the activation of the uPAR-uPA-MMP-2 cascade. CONCLUSION: Our results suggest that SF plays a role in promoting pancreatic cancer metastasis via activation of the uPA-plasminogen-MMP-2 cascade.

BACKGROUND: Urokinase-type plasminogen activator (u-PA) has been reported to overexpress in several types of human cancers and correlate with cancer progression. The present study was performed to evaluate the significance of expression of u-PA on the progression of prostate cancer. MATERIALS AND METHODS: expression of u-PA protein was investigated immunohistochemically on paraffin-embedded section from 61 patients with untreated prostate cancer. The correlation between the u-PA expression and clinical outcome was examined. RESULTS: u-PA was expressed in the cytoplasm of glandular cells of 56% patients. Higher expression of u-PA protein was positively correlated with bone metastasis (p = 0.011). The cause-specific survival rate was significantly lower in u-PA-positive patients than that in u-PA-negative patients (p = 0.0012). In those with bone metastasis, patients with u-PA expression had worse cause-specific survival than those without u-PA expression (p = 0.030). CONCLUSION: Increased expression of u-PA is a feature of bone metastasis in patients with prostate cancer. u-PA expression is a prognostic factor in patients with prostate cancer.

PURPOSE: To assess whether preoperative plasma levels of urokinase-type plasminogen activator (uPA) and its soluble receptor (uPAR) would predict cancer of the prostate (CaP) presence, stage, and prognosis. PATIENTS AND METHODS: Plasma levels of uPA and uPAR were measured in patients who underwent radical prostatectomy for clinically localized CaP (preoperative, n = 429; postoperative, n = 76), 44 healthy men, 19 patients with metastases to regional lymph nodes, and 10 patients with bone metastases. RESULTS: uPA and uPAR levels were significantly elevated in patients with CaP compared with healthy men and significantly declined after prostate removal. In CaP patients, uPA and uPAR levels both increased significantly from patients with nonmetastatic CaP to patients with lymph node metastases to patients with skeletal metastases. On univariate analysis, preoperative uPA and uPAR levels were significantly elevated in patients with extracapsular extension, seminal vesicle involvement, higher prostatectomy Gleason sum, lymph node invasion, lymphovascular invasion, perineural invasion, and higher tumor volume. Higher preoperative uPAR was associated with biochemical progression in univariate analysis. Conversely, higher preoperative uPA was independently associated with biochemical progression in preoperative or postoperative multivariate models. In patients with biochemical progression, preoperative uPA and uPAR were both significantly associated with shorter postprogression total serum prostate-specific antigen doubling times, failure to respond to salvage local radiation therapy, and/or development of distant metastasis. CONCLUSION: Elevation of plasma uPA and uPAR levels in CaP patients seems to be partly caused by local release from the prostate. Plasma levels of uPA and uPAR are associated with features of biologically aggressive CaP, disease progression after radical prostatectomy, and metastasis.

Recent studies have shown that small interfering RNA (siRNA) silences genes at the transcriptional level in human cells. However, the therapeutic potential of siRNA-mediated transcriptional gene silencing remains unclear. Here, we show that siRNA targeted to the urokinase plasminogen activator (uPA) promoter induced epigenetic transcriptional silencing in human prostate cancer cells. This silencing resulted in a dramatic reduction of tumor cell invasion and angiogenesis in vitro. Furthermore, the results from a bioluminescence tumor/metastasis model showed that the silencing of uPA significantly inhibits prostate tumor growth and the incidence of lung metastasis. Our findings represent a potentially powerful new approach to not only epigenetic silencing of metastasis or growth-promoting genes as a cancer therapy, but also as a means to shed light on how aberrant de novo methylation during cancer progression might be targeted to specific sequences.