High Plasminogen Activator Inhibitor-1 Expression Research Articles

Abstract 1684: Plasminogen activator inhibitor-1 (PAI-1) promotes cisplatin resistance in ovarian cancer cells by inhibiting ROS-mediated apoptosis and ferroptosis

Abstract Resistance to platinum-based chemotherapy is one of major causes of therapy failure and tumor recurrence in ovarian cancer patients. However, the molecular mechanism of platinum resistance is not fully understood. Here, we compared gene expression between cisplatin-sensitive and -resistant ovarian cancer cells using gene expression microarray analysis and found the significantly up-regulated expression of SERPINE1 encoding plasminogen activator inhibitor-1 (PAI-1), a serine protease regulating the fibrinolysis and extracelluar matrix, in cisplatin-resistant ovarian cancer cells. The correlation of high PAI-1 expression with low cisplatin sensitivity was confirmed in ovarian cancer cells. PAI-1 overexpression in ovarian cancer cells significantly decreased the sensitivity to cisplatin, whereas PAI-1 down-regulation by SERPINE1 siRNA or PAI-1 inhibitor increased cisplatin sensitivity. PAI-1 inhibited cisplatin-induced apoptosis in ovarian cancer cells by suppressing reactive oxygen species (ROS) production and DNA damage. PAI-1 also decreased cisplatin-induced ferroptosis through the upregulation of GPX4 levels. Furthermore, Kaplan-Meier survival analysis using TGGA data demonstrated that high PAI-1 expression was significantly associated with shorter platinum-free survival of patients with ovarian cancer. Collectively, these results illustrate that PAI-1 promotes cisplatin resistance in ovarian cancer cells by inhibiting ROS-mediated apoptosis and ferroptosis, suggesting that targeting PAI-1 increases the sensitivity to cisplatin in ovarian cancer. Citation Format: Mi Jeong Kwon, Ha Yeong Chae, So Young Lee, Shin Ung Kang, Tae Woong Jung, Soo Youn Cho, Jinil Han, Hyojin Jeong, Chang Ohk Sung, Young Kee Shin. Plasminogen activator inhibitor-1 (PAI-1) promotes cisplatin resistance in ovarian cancer cells by inhibiting ROS-mediated apoptosis and ferroptosis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1684.

Immunoreactivity of Plasminogen Activator Inhibitor 1 and Its Correlation with Dysmenorrhea and Lesional Fibrosis in Adenomyosis

Adenomyosis is associated with dysmenorrhea, infertility, and lesional fibrosis. The pathogenesis of adenomyosis is still unclear. Plasminogen activator inhibitor 1 (PAI-1) plays important roles in pathological activities like tumor metastasis and endometriosis. Our objective was to investigate the expression and localization of PAI-1 in eutopic and ectopic endometrium with adenomyosis and in endometrium without adenomyosis. We also sought to determine the relationship between PAI-1 immunoreactivity and the severity of dysmenorrhea and the extent of lesional fibrosis in adenomyosis. PAI-1 expression was significantly higher in the ectopic endometrium of patients with adenomyosis than in both the eutopic endometrium of patients with adenomyosis and the endometrium of controls. Ectopic PAI-1 expression correlated positively with dysmenorrhea visual analog scale (VAS) scores and the extent of lesional fibrosis in adenomyosis. High PAI-1 expression increased the likelihood of moderate to severe dysmenorrhea in adenomyosis. These results suggest that PAI-1 is involved in the adenomyosis-associated dysmenorrhea and lesional fibrosis, which provide a potential target in treating symptomatic adenomyosis.

PAI-1 overexpression promotes invasion and migration of esophageal squamous carcinoma cells.

Esophageal squamous cell carcinoma (ESCC) is one of the most common cancers worldwide. Plasminogen activator inhibitor-1 (PAI-1), encoded by SERPINE1, is highly expressed in various types of tumor tissues, which contributes to cancer progression. The present study explored the role and underlying mechanisms of PAI-1 in ESCC. We found that the PAI-1 protein was extracellularly secreted more from ESCC cells with high PAI-1 expression using Western blotting and enzyme linked immunosorbent assay (ELISA). Knockdown of SERPINE1 expression significantly inhibited the invasion and migration of ESCC KYSE150 and KYSE450 cell lines, which could be restored when adding exogenous human recombinant PAI-1 into the culture medium of the cells stably expressing SERPINE1 shRNA. In vivo experiments showed that SERPINE1 knockdown significantly inhibited xenograft growth and lung metastasis of ESCC cells. Molecular analysis demonstrated that PAI-1 activated AKT and ERK signaling pathways. Co-immunoprecipitation (Co-IP) assays identified that PAI-1 may interact with the membrane receptor LDL receptor related protein 1 (LRP1). These results indicated that overexpression of PAI-1, through interacting with LRP1, might enhance invasion and migration of ESCC cells as well as promote ESCC progression.

Expression, clinicopathologic and prognostic significance of plasminogen activator inhibitor 1 in hepatocellular carcinoma.

Thus far, biological roles of plasminogen activator inhibitor 1 (PAI1) in hepatocellular carcinoma (HCC) remain controversial. Moreover, its expression, clinicopathologic and prognostic significance in HCC have not been comprehensively investigated, therefore needing further evidence. PAI1 expression was measured, using tissue microarray-based immunohistochemical staining, in matched HCC and adjacent liver samples from 178 patients with HCC after curative resection. The correlations of PAI1 H-scores with clinicopathologic variables and survival were further evaluated. Its prognostic value was finally confirmed in some public databases. It was found that PAI1 expression was significantly higher in HCC than in adjacent liver tissues. Moreover, high PAI1 expression was more frequent in those with multiple lesions. Univariate analyses showed that PAI1 expression was negatively associated with both overall and relapse-free survival. Although PAI1 expression was not statistically significant in multivariate Cox regression test, combination of it with TNM stage effectively distinguished survival and relapse, and served as an independent prognostic factor. In the online available datasets of HCC and liver cancer used, SERPINE1, the gene encoding PAI1, was also revealed to be prognostic. Our data suggested that high PAI1 expression was predictive for unfavorable biological behavior and long-term prognosis in HCC.

Association of plasminogen-activator inhibitor 1 (PAI-1) 4G/5G gene polymorphism with survival and chemotherapy-related vascular toxicity in non-seminomatous testicular cancer (TC)

5083 Background: High PAI-1 expression by tumor has been associated with poor prognosis in different cancer types, while high systemic PAI-1 levels may increase the risk of vascular thrombosis. We investigated whether the 4G/5G del/ins polymorphism in the PAI-1 promoter (rs1799889; 4G might lead to higher transcription), is associated with differences in survival and prevalence of cardiovascular events in TC. METHODS: Data were collected on survival and cardiovascular events (venous thromboembolism [VTE] and coronary heart disease [CHD]) of TC patients treated with standard platinum based chemotherapy from 1977-2004. PAI-1 genotype was determined from non-tumor genomic DNA by a Taqman SNP assay. Genotypes were compared for survival (Kaplan-Meier curves + log-rank and Cox-regression analysis), disease outcome (logistic regression) and prevalence of VTE and CHD (χ(2)-test). RESULTS: Data are available for 324 patients with median follow-up of 10 yrs (range 0-28). The 3 genotypes 4G/4G (n = 84), 4G/5G (n = 164), and 5G/5G (n = 76) do not differ in age and initial chemotherapy regime. However, the 4G/4G variant shows a higher prevalence of International Germ Cell Cancer Classification (IGCCC) poor prognosis compared to 4G/5G + 5G/5G (24% vs 10%; p = 0.003), as well as a decreased TC related survival compared to 4G/5G + 5G/5G (83% vs 94%; p = 0.001) with a hazard ratio of 2.68 for TC related death (95%CI 1.26-5.72; adjusted for IGCCC p = 0.011). In addition, the 4G/4G variant shows an odds ratio of 3.35 for refractory TC and early relapses (<2 yrs) (95% CI 1.48-7.58; p = 0.004). The 3 genotypes do not differ significantly in prevalence of VTE (4G/4G 11.9%, 4G/5G 8.5%, 5G/5G 7.9%; p = 0.616) and CHD during/after chemotherapy (4G/4G 6.0%; 4G/5G 4.9%; 5G/5G 2.6%; p = 0.594). CONCLUSIONS: The 4G/4G variant of the PAI-1 4G/5G gene polymorphism is associated with IGCCC poor prognosis, reduced survival and higher prevalence of refractory disease and early relapses. No effect on vascular toxicity was found. The 4G/4G variant of the PAI-1 gene may be an unfavorable prognostic factor as well as an unfavorable predictive factor for response to chemotherapy in patients with TC. No significant financial relationships to disclose.

Statins suppress glucose-induced plasminogen activator inhibitor-1 expression by regulating RhoA and nuclear factor-kB activities in cardiac microvascular endothelial cells

The aim of this study was to investigate the possible proinflammatory signaling pathways involved in statin inhibition of glucose-induced plasminogen activator inhibitor-1 (PAI-1) expression in cardiac microvascular endothelial cells (CMECs). Primary rat CMECs were grown in the presence of 5.7 or 23 mmol/L glucose. PAI-1 mRNA and protein expression levels were measured by realtime polymerase chain reaction, Western blotting and enzyme-linked immunosorbent assay, respectively. A pull-down assay was performed to determine RhoA activity. IκBα protein expression was measured by Western blotting, nuclear factor (NF)-κB activation was detected by electrophoretic mobility shift assay and its transcription activity was determined by a dual luciferase reporter gene assay. PAI-1 mRNA and protein expression levels were both increased with high glucose concentrations, but they were significantly suppressed by simvastatin and atorvastatin treatment (P < 0.01) and the effects were reversed by mevalonate (100 μmol/L) and geranylgeranyl pyrophosphate (10 μmol/L) but not farnesyl pyrophosphate (10 μmol/L). Such effects were similar to those of a RhoA inhibitor, C3 exoenzyme (5 μg/mL), inhibitors of RhoA kinase (ROCK), Y-27632 (10 μmol/L) and hydroxyfasudil (10 μmol/L) and an NF-κB inhibitor, BAY 11-7082 (5 μmol/L). High glucose-induced RhoA and NF-κB activations in CMECs were both significantly inhibited by statins (P < 0.01). Simvastatin and atorvastatin equally suppress high glucose-induced PAI-1 expression. These effects of statins may occur partly by regulating the RhoA/ROCK-NF-κB pathway. The multifunctional roles of statins may be particularly beneficial for patients with metabolic syndrome.

PAI-1 expression and its regulation by promoter 4G/5G polymorphism in clear cell renal cell carcinoma

AimsTo characterise patients with high plasminogen activator inhibitor-1 (PAI-1) expression as oral PAI-1 antagonists are currently in preclinical trials, and to determine whether the PAI-1 promoter 4G/5G polymorphism regulates PAI-1...

Inhibition of NF-κB prevents high glucose-induced proliferation and plasminogen activator inhibitor-1 expression in vascular smooth muscle cells

Recent epidemiologic studies clearly showed that early intensive glucose control has a legacy effect for preventing diabetic macrovascular complications. However, the cellular and molecular processes by which high glucose leads to macrovascular complications are poorly understood. Vascular smooth muscle cell (VSMC) dysfunction due to high glucose is a characteristic of diabetic vascular complications. Activation of nuclear factor-κB (NF-κB) may play a key role in the regulation of inflammation and proliferation of VSMCs. We examined whether VSMC proliferation and plasminogen activator inhibitor-1 (PAI-1) expression induced by high glucose were mediated by NF-κB activation. Also, we determined whether selective inhibition of NF-κB would inhibit proliferation and PAI-1 expression in VSMCs. VSMCs of the aorta of male SD rats were treated with various concentrations of glucose (5.6, 11.1, 16.7, and 22.2 mM) with or without an inhibitor of NF-κB or expression of a recombinant adenovirus vector encoding an IκB-α mutant (Ad-IκBαM). VSMC proliferation was examined using an MTT assay. PAI-1 expression was assayed by real-time PCR and PAI-1 protein in the media was measured by ELISA. NF-κB activation was determined by immunohistochemical staining, NF-κB reporter assay, and immunoblotting. We found that glucose stimulated VSMC proliferation and PAI-1 expression in a dose-dependent manner up to 22.2 mM. High glucose (22.2 mM) alone induced an increase in NF-κB activity. Treatment with inhibitors of NF-κB such as MG132, PDTC or expression of Ad-IκB-αM in VSMCs prevented VSMC proliferation and PAI-1 expression induced by high glucose. In conclusion, inhibition of NF-κB activity prevented high glucose-induced VSMC proliferation and PAI-1 expression.

Association of plasminogen-activator inhibitor 1 (PAI-1) 4G/5G gene polymorphism with survival and chemotherapy-related vascular toxicity in non-seminomatous testicular cancer (TC)

5083 Background: High PAI-1 expression by tumor has been associated with poor prognosis in different cancer types, while high systemic PAI-1 levels may increase the risk of vascular thrombosis. We investigated whether the 4G/5G del/ins polymorphism in the PAI-1 promoter (rs1799889; 4G might lead to higher transcription), is associated with differences in survival and prevalence of cardiovascular events in TC. Methods: Data were collected on survival and cardiovascular events (venous thromboembolism [VTE] and coronary heart disease [CHD]) of TC patients treated with standard platinum based chemotherapy from 1977–2004. PAI-1 genotype was determined from non-tumor genomic DNA by a Taqman SNP assay. Genotypes were compared for survival (Kaplan-Meier curves + log-rank and Cox-regression analysis), disease outcome (logistic regression) and prevalence of VTE and CHD (χ2-test). Results: Data are available for 324 patients with median follow-up of 10 yrs (range 0–28). The 3 genotypes 4G/4G (n = 84), 4G/5G (n = 164), and 5G/5G (n = 76) do not differ in age and initial chemotherapy regime. However, the 4G/4G variant shows a higher prevalence of International Germ Cell Cancer Classification (IGCCC) poor prognosis compared to 4G/5G + 5G/5G (24% vs 10%; p = 0.003), as well as a decreased TC related survival compared to 4G/5G + 5G/5G (83% vs 94%; p = 0.001) with a hazard ratio of 2.68 for TC related death (95%CI 1.26–5.72; adjusted for IGCCC p = 0.011). In addition, the 4G/4G variant shows an odds ratio of 3.35 for refractory TC and early relapses (&lt;2 yrs) (95% CI 1.48–7.58; p = 0.004). The 3 genotypes do not differ significantly in prevalence of VTE (4G/4G 11.9%, 4G/5G 8.5%, 5G/5G 7.9%; p = 0.616) and CHD during/after chemotherapy (4G/4G 6.0%; 4G/5G 4.9%; 5G/5G 2.6%; p = 0.594). Conclusions: The 4G/4G variant of the PAI-1 4G/5G gene polymorphism is associated with IGCCC poor prognosis, reduced survival and higher prevalence of refractory disease and early relapses. No effect on vascular toxicity was found. The 4G/4G variant of the PAI-1 gene may be an unfavorable prognostic factor as well as an unfavorable predictive factor for response to chemotherapy in patients with TC. No significant financial relationships to disclose.

Two distinct expression patterns of urokinase, urokinase receptor and plasminogen activator inhibitor-1 in colon cancer liver metastases

With great interest we read the article Two distinct expression patterns of urokinase, urokinase receptor and plasminogen activator inhibitor-1 (PAI1) in colon cancer liver metastases’ by Martin Illemann et al. The authors describe 2 distinct patterns of the expression of urokinase-type plasminogen activator (uPA), urokinase-type plasminogen activator receptor (uPAR), and PAI1 in 14 colon cancer liver metastases that correlate closely with 2 morphological growth patterns. In the liver metastases with a predominantly desmoplastic reaction at the periphery, the expression of uPAR, uPA and PAI1 is very similar to that found in the primary colon tumours. These molecules were primarily expressed in stromal cells at the metastases’ periphery. Furthermore, uPAR and uPA were also expressed in a subset of budding cancer cells at the tumour interface. In the liver metastases of which the growth is characterised by direct contact between the cancer cells and the hepatocytes on the contrary, uPAR and uPA-mRNA expression were only seen associated with the presence of necrosis within the liver metastases. In addition, PAI1-immunoreactivity was in all liver metastases seen in hepatocytes at the metastases periphery. We have been studying growth patterns of human colorectal cancer metastases for many years now. As mentioned by Illeman et al., we described 3 different growth patterns with differences in angiogenesis and desmoplasia. In the desmoplastic growth pattern, the metastases are separated from the surrounding liver parenchyma by a rim of desmoplastic stroma in which a dense inflammatory infiltrate and numerous capillaries are present. In the pushing pattern, liver cell plates are pushed aside and run in parallel with the circumference of the metastases at the tumour–liver parenchyma interface. There is no desmoplastic stroma formation. In the nonangiogenic replacement growth pattern, tumour cells replace hepatocytes in the liver plates, at the interface or throughout the metastasis, conserving tissue architecture of the liver, without inflammation or fibrosis. The growth pattern of liver metastases seems not only to vary between tumours of the same histological subtype, but also between tumours of a different subtype. Although liver metastases of patients with colorectal cancer grow according to the desmoplastic , pushing and replacement growth pattern in, respectively, 42, 46 and 12%, liver metastases of patients with breast cancer on the contrary grow according to the replacement growth pattern in virtually all cases. Although we have published data that show important differences in hypoxia and angiogenesis between the different growth patterns, the biology and underlying molecular mechanisms of the different growth pattern of liver metastases remain largely unknown. Therefore, the findings of Illeman et al. regarding different expression of 3 key components of the uPA extracellular protease system in metastases with a desmoplastic and pushing growth pattern are important. In this letter, we would like to add extra data suggesting a role not only in liver metastases of patients with colorectal cancer, but also of patients with breast cancer. In a study of differential expression of hypoxia and (lymph)angiogenesis-related genes at different metastatic sites in breast cancer, uPA (in that paper called PLAU) was among the 49 genes that were differentially expressed between primary tumours and/or lymph node metastases and/or liver metastases. The expression of uPA was higher in liver metastases compared with primary breast tumours and to lymph node metastases. There was no significant difference between the expression of uPA between primary breast tumours and lymph node metastases. uPAR and PAI1 were not investigated in that study. To further explore possible differences in expression of the uPA system between breast cancer localisations in different organs, we now analysed the expression of uPA, uPAR and PAI1 using the data described in that paper. The localisations were grouped in primary tumours (n 5 11), lymph node metastases (n 5 15), liver metastases (n 5 4), lung metastases (n 5 8) and other metastases (n 5 24). For a detailed description of materials and methods, we refer to the previous publication. Figure 1 represents the results. The median mRNA expression for uPA was significantly lower in liver metastases compared with primary tumours (p 5 0.04) and lymph node metastases (p 5 0.04). There was a borderline significant difference in uPA mRNA expression between liver metastases and other metastases (p 5 0.09), and there was no difference between liver metastases and lung metastases. There was a significantly higher mRNA expression of PAI1 in liver metastases than in lymph node metastases (p 5 0.04) and a borderline significant higher expression in liver metastases than in primary tumours (p 5 0.08). There were no significant differences in the expression of uPAR between liver metastases and other tumour sites. Furthermore, there was a significantly higher PAI1 expression in lung metastases, than in primary tumours (p 5 0.009), lymph node metastases (p 5 0.002) and other metastases (p 5 0.03) and there was a

High glucose induces plasminogen activator inhibitor-1 expression through Rho/Rho-kinase-mediated NF-κB activation in bovine aortic endothelial cells

Recently, it has become evident that elevated levels of plasminogen activator inhibitor-1 (PAI-1) are associated with myocardial infarction and stroke, especially in patients with diabetes. The molecular mechanisms involved in hyperglycemia-induced PAI-1 expression in bovine aortic endothelial cells (BAEC) were investigated.PAI-1 expression in BAEC was significantly increased in accordance with the concentration of glucose in media from 5.7mM to 23mM. Stimulation with high glucose (23mM) significantly increased small GTPase RhoA activation. Pretreatment with a Rho-kinase inhibitor, Y-27632 (1–10μM), significantly blocked high glucose-induced PAI-1 expression. NF-κB activity determined using the luciferase reporter gene assay was significantly enhanced by high glucose, and pretreatment with Y-27632 inhibited high glucose-induced PAI-1 expression at the basal level. An inhibitor of NF-κB action, namely parthenolide (0.1μM), BAY 11-7082 (5μM) and SN50 (1μM), significantly blocked high glucose-mediated PAI-1 expression to a level with low glucose (5.7mM). These data suggested that high glucose-induced PAI-1 expression in endothelial cells is mediated by NF-κB activation through the Rho/Rho-kinase pathway. Inhibition of Rho/Rho-kinase signaling might be a novel target for diabetes and metabolic syndrome.

An association between the 4G polymorphism in the PAI-1 promoter and the development of aggressive fibromatosis (desmoid tumor) in familial adenomatous polyposis patients

Aggressive fibromatosis is a mesenchymal neoplasm associated with mutations resulting in beta-catenin mediated transcriptional activation. Plasminogen activator inhibitor-1 (PAI-1) is expressed at a high level in aggressive fibromatosis, and using transgenic mice, we found that PAI-1 plays an important role in aggressive fibromatosis tumor formation. Familial adenomatous polyposis is associated with Adenomatous Polyposis Coli gene mutations resulting in beta-catenin mediated transcriptional activation, yet only some patients develop aggressive fibromatosis. Since PAI-1 expression is influenced by a promoter 4G/5G polymorphism, we investigated the incidence of this polymorphism in familial adenomatous polyposis patients who did and who did not develop aggressive fibromatosis, as well as sporadic aggressive fibromatosis patients. There was a trend towards association of the 4G allele (associated with high PAI-1 expression) with the development of aggressive fibromatosis in familial adenomatous polyposis patients (50% vs. 19%, P = 0.1). In familial adenomatous polyposis patients who did not develop aggressive fibromatosis, there was a significantly lower proportion of patients with a 4G allele compared to the healthy control (19% vs. 51%, P = 0.0286). The lower incidence of 4G polymorphism in the PAI-1 promoter may be preventive against the development of aggressive fibromatosis. This data provides additional evidence supporting an important role for PAI-1 in the pathogenesis of aggressive fibromatosis.

PAI-1 (Plasminogen activator inhibitor-1) expression levels in colorectal cancers and corresponding normal tissues

10094 Background: We performed a quantitative RT-PCR for Plasminogen Activator Inhibitor-1 (PAI-1) gene in 55 surgical specimens of colorectal cancer (CRC) and corresponding normal mucosa. To test the hypothesis that PAI-1 may serve as a candidate marker for the malignant potential of CRC, we evaluated the possible relationship between PAI-1 gene expression levels and clinicopathological findings in CRC. Next, to investigate the mechanism of PAI-1 overexpression in CRC, we compared the PAI-1 expression levels in these cancers with those in the corresponding normal tissues. Results: A significant increase in PAI-1 expression scores was observed in node-positive CRCs (2.19Å}0.43) compared to negative ones (0.35Å}0.42) (P=0.0037) as well as in CRCs with distant metastasis (3.50Å}1.18) compared to negative ones (0.99Å}0.30). A significant increase in PAI-1 expression scores was observed in lymph node metastasis-positive CRCs (2.19Å}0.43) compared to negative ones (0.35Å}0.42) (P=0.0037) as well as in distant metastasis-positive CRCs (3.50Å}1.18) compared to negative ones (0.99Å}0.30). The PAI-1 expression score markedly increased with the tumor stage (P=0.0063; ANOVA test). Moreover, multivariate analysis revealed the PAI-1 expression score to be a strong and independent prognostic factor for CRC (P=0.0432). There was a significant correlation between CRC and corresponding normal PAI-1 expressions with a Spearman’s rank correlation coefficient of 0.81 (P &lt; 0.0001). Conclusion: These results suggested that PAI-1 might serve as a new parameter for the prediction of prognoses in CRC. Taken together, PAI-1 overexpression in CRCs might originate from higher PAI-1 expression in the corresponding normal tissues and result in a malignant phenotype of these cancers. No significant financial relationships to disclose.

Plasminogen activator inhibitor-1 polymorphism is associated with increased risk for oral cancer

In light of the recently observed contribution of thrombosis-related factors to carcinogenesis, we investigated the possible association of plasminogen activator inhibitor-1 (PAI-1) with increased risk for oral cancer. In DNA samples of 104 patients with oral squamous cell carcinoma and 106 healthy controls of comparable ethnicity, age and sex, we studied the 4G/5G polymorphism in the PAI-1 gene, which affects its expression. The mutant 4G allele and carrier frequencies were significantly increased in patients compared to controls (65.9% versus 49.5%; 88.5% versus 69.8% respectively, P<0.01). That increase was even higher in patients with a positive family history for thrombophilia or without one for cancer (P<0.001). Interestingly, significant difference from controls was observed only in patients with cancer stages I and II. These findings suggest that the 4G allele, by resulting in higher PAI-1 expression, is a major contributing factor in early stages of oral oncogenesis. Possibly, increased PAI-1 promotes initial development of oral cancer through regulation of cell detachment and delays further tumor progression by inhibiting vascularization.

Reactive oxygen species mediate high glucose–induced plasminogen activator inhibitor-1 up-regulation in mesangial cells and in diabetic kidney

Plasminogen activator inhibitor-1 (PAI-1) plays an important role in remodeling of extracellular matrix (ECM) in the glomeruli. PAI-1 is up-regulated by high glucose and is overexpressed in diabetic kidney. Since reactive oxygen species (ROS) mediate ECM accumulation in diabetic glomeruli and was recently found to mediate transforming growth factor-beta1 (TGF-beta1)-induced PAI-1 up-regulation in glomerular mesangial cells, we examined the role of ROS in high glucose-induced PAI-1 expression in cultured glomerular mesangial cells and in streptozotocin-induced diabetic rat glomeruli. Growth arrested and synchronized primary rat mesangial cells were treated with different concentrations of glucose in the presence or absence of N-acetylcysteine (NAC) or trolox, or after cellular reduced form of glutathione (GSH) depleted with DL-buthionine-(S,R)-sulfoximine (BSO). Taurine was administered to diabetic rats from 2 days to 4 weeks after streptozotocin injection. Urinary protein excretion, glomerular volume, and fractional mesangial area were measured as markers of renal injury and lipid peroxide (LPO) as an oxidative stress marker. PAI-1 mRNA expression was measured by Northern blot analysis in mesangial cells and reverse transcription-polymerase chain reaction (RT-PCR) in glomeruli, PAI-1 protein by Western blot analysis and enzyme-linked immunosorbent assay (ELISA), and plasmin activity by fluorometry. High glucose significantly increased PAI-1 mRNA and protein expression and decreased plasmin activity in mesangial cells. Equimolar concentrations of l-glucose or mannitol did not affect PAI-1 expression. BSO pretreatment significantly increased basal PAI-1 expression and amplified the response to high glucose. NAC effectively inhibited high glucose-induced, but not basal, PAI-1 expression. Reduced plasmin activity in mesangial cells by high glucose was rescued by antioxidants. Anti-TGF-beta antibody inhibited both high glucose- and H(2)O(2)-induced PAI-1 up-regulation. Taurine significantly reduced plasma LPO, glomerular PAI-1 expression, glomerular volume, fractional mesangial area, and proteinuria in streptozotocin-induced diabetic rats. These results demonstrate that ROS mediate high glucose-induced up-regulation of PAI-1 expression in cultured mesangial cells and in diabetic glomeruli. Since both high glucose and TGF-beta1 induce cellular ROS and ROS mediate both high glucose- and TGF-beta1-induced PAI-1, ROS appear to amplify TGF-beta1 signaling in high glucose-induced PAI-1 up-regulation. Antioxidants can prevent accumulation of ECM protein in diabetic glomeruli partly by abrogating up-regulation of PAI-1 and suppression of plasmin activity.

Nipple Aspirate Fluid Expression of Urokinase-Type Plasminogen Activator, Plasminogen Activator Inhibitor-1, and Urokinase-Type Plasminogen Activator Receptor Predicts Breast Cancer Diagnosis and Advanced Disease

Tumor expression of urokinase-type plasminogen activator (uPA), plasminogen activator inhibitor-1 (PAI-1), and uPA receptor (uPAR) are breast cancer prognostic factors. Less is known about their usefulness in breast cancer diagnosis. Nipple aspirate fluid (NAF) is secreted into the breast duct and collected noninvasively, making it potentially useful both in breast cancer diagnosis and prognosis. We determined the association of uPA, PAI-1, and uPAR levels in NAF with breast cancer (1) detection and (2) advanced disease. A total of 88 NAF specimens were collected from women with or without breast cancer, and uPA, PAI-1, and uPAR expression were measured by enzyme-linked immunosorbent assay. uPA and uPAR were independent predictors of cancer presence; uPAR was also an independent predictor of advanced disease stage. Higher PAI-1 expression in breast cancer that was found with univariate analysis was not observed after logistic regression was applied. NAF evaluation of uPA, uPAR, and, perhaps, PAI-1 (significant only in univariate analysis) may provide useful breast cancer diagnostic and prognostic information.

Increased Plasminogen Activator Inhibitor-1 in Keloid Fibroblasts May Account for their Elevated Collagen Accumulation in Fibrin Gel Cultures

Proteolytic degradation of the provisional fibrin matrix and subsequent substitution by fibroblast-produced collagen are essential features of injury repair. Immunohistochemical studies revealed that although dermal fibroblasts of normal scars and keloids expressed both urokinase type plasminogen activator (uPA) and plasminogen activator inhibitor-1 (PAI-1), keloid fibroblasts had a much higher PAI-1 expression. In long-term three-dimensional fibrin gel cultures (the in vitro fibroplasia model), normal fibroblasts expressed moderate and modulated activity levels of uPA and PAI-1. In contrast, keloid fibroblasts expressed a persistently high level of PAI-1 and a low level of uPA. The high PAI-1 activity of keloid fibroblasts correlated with their elevated collagen accumulation in fibrin gel cultures. Substituting collagen for fibrin in the gel matrix resulted in increased uPA activity and reduced collagen accumulation of keloid fibroblasts. Furthermore, decreasing PAI-1 activity of keloid fibroblasts in fibrin gel cultures with anti-PAI-1-neutralizing antibodies also resulted in a reduction in collagen accumulation by keloid fibroblasts. Cumulatively, these results suggest that PAI-1 overexpression is a consistent feature of keloid fibroblasts both in vitro and in vivo, and PAI-1 may play a causative role in elevated collagen accumulation of keloid fibroblasts.

Plasminogen activator inhibitor-1 is an independent poor prognostic factor for survival in advanced stage epithelial ovarian cancer patients.

High levels of plasminogen activator inhibitor-1 (PAI-1) in tissue extracts have been associated with poor prognosis in many epithelial cancers. Ovarian cancers contain a higher concentration of PAI-1 than benign ovarian tumors or normal ovaries. Reports, however, on the prognostic value of PAI-1 content in ovarian cancers have been conflicting. We used immunohistochemistry to study the primary and metastatic tissues from 131 epithelial ovarian cancer cases. This group has been previously characterized for the expression of urokinase (uPA), uPA receptor, PAI-2 and macrophage colony-stimulating factor (CSF-1). The intensity and extent of staining for PAI-1 in the tumor epithelium was scored. Kaplan-Meier curves of survival were compared using the log-rank test. The Cox regression model was utilized for multivariate analysis. Approximately 50% of the primary tumors and metastases expressed PAI-1. Among invasive stages III and IV patients, those whose primary tumors expressed PAI-1 had a shorter overall survival. The combination of strong expression of PAI-1 and expression of uPA was a highly significant factor for short disease-free and overall survival. Similar results were seen with the combination of high PAI-1 and low PAI-2 expression. Strong PAI-1 expression was significantly associated with expression of uPA receptor or CSF-I in the tumor epithelium, but not with standard clinical parameters, and was an independent prognostic factor for poor survival on multivariate analysis. Our results show that PAI-1 expression in the primary tumor epithelium is an independent poor prognostic factor for survival, underscoring the tumor protective role of PAI-1 in ovarian cancer biology.

Plasminogen activator inhibitor‐1 is an independent poor prognostic factor for survival in advanced stage epithelial ovarian cancer patients

High levels of plasminogen activator inhibitor-1 (PAI-1) in tissue extracts have been associated with poor prognosis in many epithelial cancers. Ovarian cancers contain a higher concentration of PAI-1 than benign ovarian tumors or normal ovaries. Reports, however, on the prognostic value of PAI-1 content in ovarian cancers have been conflicting. We used immunohistochemistry to study the primary and metastatic tissues from 131 epithelial ovarian cancer cases. This group has been previously characterized for the expression of urokinase (uPA), uPA receptor, PAI-2 and macrophage colony-stimulating factor (CSF-1). The intensity and extent of staining for PAI-1 in the tumor epithelium was scored. Kaplan-Meier curves of survival were compared using the log-rank test. The Cox regression model was utilized for multivariate analysis. Approximately 50% of the primary tumors and metastases expressed PAI-1. Among invasive stages III and IV patients, those whose primary tumors expressed PAI-1 had a shorter overall survival. The combination of strong expression of PAI-1 and expression of uPA was a highly significant factor for short disease-free and overall survival. Similar results were seen with the combination of high PAI-1 and low PAI-2 expression. Strong PAI-1 expression was significantly associated with expression of uPA receptor or CSF-1 in the tumor epithelium, but not with standard clinical parameters, and was an independent prognostic factor for poor survival on multivariate analysis. Our results show that PAI-1 expression in the primary tumor epithelium is an independent poor prognostic factor for survival, underscoring the tumor protective role of PAI-1 in ovarian cancer biology. Int. J. Cancer (Pred. Oncol.) 79:449–454, 1998.© 1998 Wiley-Liss, Inc.