Immunohistochemical localization of a urokinase-type plasminogen activator system in squamous cell carcinoma of the oral cavity: association with mode of invasion and lymph node metastasis

Expression of Serpin Family E Member 1 (SERPINE1) Is Associated with Poor Prognosis of Gastric Adenocarcinoma

BACKGROUND

The aberrant expression of serpin family E member 1 (SERPINE1) is associated with carcinogenesis. This study assessed the alteration of SERPINE1 expression for an association with gastric adenocarcinoma prognosis.

METHODS

The Cancer Genome Atlas (TCGA) dataset was applied to investigate the impact of SERPINE1 expression on the survival of patients afflicted with gastric cancer. Subsequently, 136 samples from the Affiliated Huaian No. 1 People's Hospital of Nanjing Medical University were subjected to qRT-PCR and Western blot to validate the expression level of SERPINE1 between tumor and adjacent normal tissues. The correlation between the expression of SERPINE1 with the clinicopathological features in TCGA patients was analyzed using Wilcoxon signed-rank and logistic regression tests. The potential molecular mechanism associated with SERPINE1 expression in gastric cancer were confirmed using gene set enrichment analysis (GSEA).

RESULTS

The TCGA data showed that SERPINE1 was overexpressed in tumor tissues compared to normal mucosae and associated with the tumor T stage and pathological grade. SERPINE1 overexpression was associated with the poor overall survival (OS) of patients. The findings were confirmed with 136 patients, that is, SERPINE1 expression was associated with poor OS (hazard ratio (HR): 1.82; 95% confidence interval (CI): 0.84-1.83; p = 0.012)) as an independent predictor (HR: 2.11, 95% CI: 0.81-2.34; p = 0.009). The resulting data were further processed by GSEA showed that SERPINE1 overexpression was associated with the activation of EPITHELIAL_MESENCHYMAL_TRANSITION, TNFA_SIGNALING_VIA_NFKB, INFLAMMATORY_RESPONSE, ANGIOGENESIS, and HYPOXIA.

CONCLUSIONS

SERPINE1 overexpression is associated with a poor gastric cancer prognosis.

Automatic discrimination of Yamamoto-Kohama classification by machine learning approach for invasive pattern of oral squamous cell carcinoma using digital microscopic images: a retrospective study

OBJECTIVE

The Yamamoto-Kohama criteria are clinically useful for determining the mode of tumor invasion, especially in Japan. However, this evaluation method is based on subjective visual findings and has led to significant differences in determinations between evaluators and facilities. In this retrospective study, we aimed to develop an automatic method of determining the mode of invasion based on the processing of digital medical images.

STUDY DESIGN

Using 101 digitized photographic images of anonymized stained specimen slides, we created a classifier that allowed clinicians to introduce feature values and subjected the cases to machine learning using a random forest approach. We then compared the Yamamoto-Kohama grades (1, 2, 3, 4C, 4D) determined by a human oral and maxillofacial surgeon with those determined using the machine learning approach.

RESULTS

The input of multiple test images into the newly created classifier yielded an overall F-measure value of 87% (grade 1, 93%; grade 2, 67%; grade 3, 89%; grade 4C, 83%; grade 4D, 94%). These results suggest that the output of the classifier was very similar to the judgments of the clinician.

CONCLUSIONS

This system may be valuable for diagnostic support to provide an accurate determination of the mode of invasion.

The Urokinase Receptor (uPAR) as a "Trojan Horse" in Targeted Cancer Therapy: Challenges and Opportunities

Simple Summary

Discovered more than three decades ago, the urokinase-type plasminogen activator receptor (uPAR) has now firmly established itself as a versatile molecular target holding promise for the treatment of aggressive malignancies. The copious abundance of uPAR in virtually all human cancerous tissues versus their healthy counterparts has fostered a gradual shift in the therapeutic landscape targeting this receptor from function inhibition to cytotoxic approaches to selectively eradicate the uPAR-expressing cells by delivering a targeted cytotoxic insult. Multiple avenues are being explored in a preclinical setting, including the more innovative immune- or stroma targeting therapies. This review discusses the current state of these strategies, their potentialities, and challenges, along with future directions in the field of uPAR targeting.

Abstract

One of the largest challenges to the implementation of precision oncology is identifying and validating selective tumor-driving targets to enhance the therapeutic efficacy while limiting off-target toxicity. In this context, the urokinase-type plasminogen activator receptor (uPAR) has progressively emerged as a promising therapeutic target in the management of aggressive malignancies. By focalizing the plasminogen activation cascade and subsequent extracellular proteolysis on the cell surface of migrating cells, uPAR endows malignant cells with a high proteolytic and migratory potential to dissolve the restraining extracellular matrix (ECM) barriers and metastasize to distant sites. uPAR is also assumed to choreograph multiple other neoplastic stages via a complex molecular interplay with distinct cancer-associated signaling pathways. Accordingly, high uPAR expression is observed in virtually all human cancers and is frequently associated with poor patient prognosis and survival. The promising therapeutic potential unveiled by the pleiotropic nature of this receptor has prompted the development of distinct targeted intervention strategies. The present review will focus on recently emerged cytotoxic approaches emphasizing the novel technologies and related limits hindering their application in the clinical setting. Finally, future research directions and emerging opportunities in the field of uPAR targeting are also discussed.

Urokinase plasminogen activator predicts poor prognosis in hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide and its prognosis remains dismal. Hence, it is important to identify the diagnostic and prognostic biomarkers for HCC. Urokinase plasminogen activator (uPA), an extracellular matrix (ECM)-degrading protease, plays a pivotal role in the invasion and metastasis of HCC.

Methods

To confirm the clinical significance of uPA in HCC, we explored uPA expression in HCC in The Cancer Genome Atlas (TCGA) database. The expression level of uPA was further verified by quantitative reverse transcription polymerized chain reaction (qRT-PCR) in 133 pairs of primary HCC samples. A survival analysis was conducted with the Kaplan-Meier method in the HCC samples and TCGA database.

Results

Our results showed that uPA was overexpressed in HCC and was significantly associated with HCC tumor size (P=0.015), differentiation grade (P=0.028), and absence of tumor encapsulation (P=0.010). Patients with high uPA expression levels had a poor outcome (P=0.026). TCGA database analysis was also consistent with our experimental results.

Conclusions

In conclusion, our findings revealed that uPA was overexpressed in HCC and was related to HCC malignant features including tumor size, differentiation grade and absence of tumor encapsulation. High uPA expression had a shorter survival time. It is a potential prognostic biomarker of HCC.

Dihydromyricetin suppresses cell metastasis in human osteosarcoma through SP-1- and NF-κB-modulated urokinase plasminogen activator inhibition

BACKGROUND

Metastasis caused a decline in the 5-years survival rate of osteosarcoma. Therefore, developing new targeted therapeutics for osteosarcoma treatment is imperative. Dihydromyricetin (DHM) has several physiological functions: it counteracts inflammation, oxidation, and antitumor properties. However, the effects of DHM on osteosarcoma and its underlying mechanisms are still not well understood.

PURPOSE

In this study, we investigated the antimetastatic properties of DHM in human osteosarcoma U-2 OS and HOS cells.

METHODS

The effects of DHM (0, 25, 50, 75, and 100 μM) on cell viability, migration, and invasion were examined. Western blotting, RT-PCR, and quantitative real-time PCR (QPCR) were determined urokinase plasminogen activator (uPA) expression. The expression of transcriptional factor SP-1 and NF-κB was determined by using immunofluorescence assay, chromatin immunoprecipitation assay, and site-directed mutagenesis luciferase reporter.

RESULTS

We observed that DHM suppresses cell migration and invasion in osteosarcoma cell lines. In addition, DHM inhibits metastasis by downregulating urokinase plasminogen activator (uPA) expression. Moreover, real-time polymerase chain reaction and promoter activity assays revealed that DHM decreased uPA expression at transcription levels. Furthermore, the inhibition of uPA expression was associated with the suppression of SP-1 and NF-κB, which bind to the uPA promoter. Regardless of blocking or inducing the extracellular signal-regulated kinase (ERK) pathway, we verified that the DHM-related suppression of uPA and cell metastasis occurred through the p-ERK pathway.

CONCLUSION

We are the first study to propose that DHM suppresses osteosarcoma metastasis through the ERK pathway and through the suppression of SP-1 and NF-κB to inhibit downstream uPA expression. DHM is a potential therapeutic agent for antimetastatic therapy against osteosarcoma.

Thrombosis Risk Associated with Head and Neck Cancer: A Review

Venous thromboembolism (VTE) is a common complication for cancer patients. VTE-associated risk varies according to the type of tumor disease. Head and neck cancer is a common cancer worldwide, and most tumors are squamous cell carcinomas due to tobacco and alcohol abuse. The risk of VTE associated with head and neck (H&N) cancer is considered empirically low, but despite the high incidence of H&N cancer, few data are available on this cancer; thus, it is difficult to state the risk of VTE. Our review aims to clarify this situation and tries to assess the real VTE risk associated with H&N cancer. We report that most clinical studies have concluded that there is a very low thrombosis risk associated with H&N cancer. Even with the biases that often exist, this clinical review seems to confirm that the risk of VTE was empirically hypothesized. Furthermore, we highlight that H&N cancer has all the biological features of a cancer associated with a high thrombosis risk, including a strong expression of procoagulant proteins, modified thrombosis/fibrinolysis mechanisms, and secretions of procoagulant microparticles and procoagulant cytokines. Thus, this is a paradoxical situation, and some undiscovered mechanisms that could explain this clinical biological ambivalence might exist.

Differential Expression Levels of Urokinase-Type Plasminogen Activator and Cathepsin D in Locally Advanced Laryngeal Squamous Cell Carcinoma: Clinical Implications

The expression levels and the prognostic impact of urokinase-type plasminogen activator (uPA) and cathepsin D (CD) were evaluated in patients with locally advanced laryngeal squamous cell carcinoma (LSCC). uPA and CD protein levels were determined by immunoluminometric or immunoenzymatic assays in the cytosol of paired sets of tumor tissues and corresponding adjacent normal mucosa (NLM) from 57 patients with stage III/IV LSCC and were correlated with a number of clinicobiological parameters of this tumor including anatomical site, tumor grade, nodal status, clinical stage, DNA ploidy, proliferation rate, and patient outcome. Median uPA levels were significantly higher in LSCC than in NLM (1.8 ng/mg of protein vs 0.3 ng/mg; p<0.001) whereas median CD levels were not significantly increased in tumor tissue compared to NLM (24 pmol/mg vs 19 pmol/mg, p=0.063). No significant correlation was observed between uPA and CD concentrations in tumor tissues (r=-0.1; p=0.4). Furthermore, the distribution analysis of uPA and CD in tumors showed no correlation between expression levels of these proteinases and the parameters mentioned above including patient outcome. However, when data were matched according to each parameter examined it was observed that the differences in uPA content between LSCC and NLM, expressed as uPA tumor/normal tissue ratio (T/M), were more marked in clinically advanced and/or aggressive forms of LSCC (i.e., node positive, stage IV, poorly and moderately differentated, aneuploid multiclonal, low S-phase, subglottis tumors). These data suggest that in such tumors altered regulation of uPA may occur to a greater extent than in less aggressive and less advanced forms of LSCC. This phenomenon was not observed for CD. However, in tumors with a high proliferation rate, in stage IV tumors as well as in those located in the supraglottis, CD levels were significantly higher than those found in the corresponding NLM (p=0.008, p=0.02 and p=0.03, respectively). In conclusion, uPA is highly expressed in locally advanced LSCC and appears to be implicated in some key events of progression of this tumor such as local invasion and/or nodal involvement, whereas CD does not seem to have a role in promoting these processes. Nevetheless, neither of these proteinases seem to be prognostically useful in patients with stage III/IV tumors.

uPA/uPAR and SERPINE1 in head and neck cancer: role in tumor resistance, metastasis, prognosis and therapy

There is strong evidence supporting the role of the plasminogen activator system in head and neck squamous cell carcinoma (HNSCC), particularly of its uPA (urokinase plasminogen activator) / uPAR (urokinase plasminogen activator receptor) and SERPINE1 components. Overexpression of uPA/uPAR and SERPINE1 enhances tumor cell migration and invasion and plays a key role in metastasis development, conferring poor prognosis. The apparent paradox of uPA/uPAR and its inhibitor SERPINE1 producing similar effects is solved by the identification of SERPINE1 activated signaling pathways independent of uPA inhibition. Both uPA/uPAR and SERPINE1 are directly linked to the induction of epithelial-to-mesenchymal transition, the acquisition of stem cell properties and resistance to antitumor agents. The aim of this review is to provide insight on the deregulation of these proteins in all these processes.

We also summarize their potential value as prognostic biomarkers or potential drug targets in HNSCC patients. Concomitant overexpression of uPA/uPAR and SERPINE1 is associated with a higher risk of metastasis and could be used to identify patients that would benefit from an adjuvant treatment. In the future, the specific inhibitors of uPA/uPAR and SERPINE1, which are still under development, could be used to design new therapeutic strategies in HNSCCs.

Urokinase-type plasminogen activator (uPA) is critical for progression of tuberous sclerosis complex 2 (TSC2)-deficient tumors

Lymphangioleiomyomatosis (LAM) is a fatal lung disease associated with germline or somatic inactivating mutations in tuberous sclerosis complex genes (TSC1 or TSC2). LAM is characterized by neoplastic growth of smooth muscle-α-actin-positive cells that destroy lung parenchyma and by the formation of benign renal neoplasms called angiolipomas. The mammalian target of rapamycin complex 1 (mTORC1) inhibitor rapamycin slows progression of these diseases but is not curative and associated with notable toxicity at clinically effective doses, highlighting the need for better understanding LAM's molecular etiology. We report here that LAM lesions and angiomyolipomas overexpress urokinase-type plasminogen activator (uPA). Tsc1^-/- and Tsc2^-/- mouse embryonic fibroblasts expressed higher uPA levels than their WT counterparts, resulting from the TSC inactivation. Inhibition of uPA expression in Tsc2-null cells reduced the growth and invasiveness and increased susceptibility to apoptosis. However, rapamycin further increased uPA expression in TSC2-null tumor cells and immortalized TSC2-null angiomyolipoma cells, but not in cells with intact TSC. Induction of glucocorticoid receptor signaling or forkhead box (FOXO) 1/3 inhibition abolished the rapamycin-induced uPA expression in TSC-compromised cells. Moreover, rapamycin-enhanced migration of TSC2-null cells was inhibited by the uPA inhibitor UK122, dexamethasone, and a FOXO inhibitor. uPA-knock-out mice developed fewer and smaller TSC2-null lung tumors, and introduction of uPA shRNA in tumor cells or amiloride-induced uPA inhibition reduced tumorigenesis in vivo These findings suggest that interference with the uPA-dependent pathway, when used along with rapamycin, might attenuate LAM progression and potentially other TSC-related disorders.

Urokinase-type plasminogen activator receptor (uPAR), tissue factor (TF) and epidermal growth factor receptor (EGFR): tumor expression patterns and prognostic value in oral cancer

Background

Tumor-specific biomarkers are a prerequisite for the development of targeted imaging and therapy in oral squamous cell carcinoma (OSCC). urokinase-type Plasminogen Activator Receptor (uPAR), Tissue Factor (TF) and Epidermal Growth Factor Receptor (EGFR) are three biomarkers that exhibit enhanced expression in many types of cancers, and have been investigated as potential biomarkers for targeted strategies and prognostication. The aim of the study was to investigate the expression patterns of uPAR, TF and EGFR and their potential prognostic value in OSCC.

Methods

Immunohistochemical expression of uPAR, TF and EGFR in tumor resection specimens from 191 patients with primary OSCC was analyzed. Overall (OS) and disease-free survival (DFS) was calculated. Associations between biomarker expression, clinicopathological factors and patient survival was analyzed using the Cox proportional hazards model for univariate and multivariate analysis, log rank and Kaplan-Meier statistics.

Results

uPAR and TF exhibited a highly tumor-specific expression pattern while EGFR also showed expression in normal tissues outside the tumor compartment. The overall positive expression rate of uPAR, TF and EGFR was 95%, 58% and 98%, respectively. High uPAR expression across the entire cohort was negatively associated with OS (p = 0.031, HR = 1.595 (95%CI 1.044–2.439)) in univariate analysis. The 5-year OS for high and low uPAR expression was 39% and 56%, respectively. The expression of TF and EGFR was not associated with survival outcome.

Conclusions

This study may suggest that uPAR and TF could potentially be attractive targets for molecular imaging and therapy in OSCC due to high positive expression rates and tumor-specific expression patterns. High uPAR expression was significantly associated with a reduced survival. uPAR seems to be a prognostic biomarker in oral cancer.

Preclinical uPAR-targeted multimodal imaging of locoregional oral cancer

OBJECTIVES

Establishing adequate resection margins and lymphatic mapping are crucial for the prognosis of oral cancer patients. Novel targeted imaging modalities are needed, enabling pre- and intraoperative detection of tumour cells, in combination with improved post-surgical examination by the pathologist. The urokinase-receptor (uPAR) is overexpressed in head and neck cancer, where it is associated with tumour progression and metastasis.

MATERIAL AND METHODS

To determine suitability of uPAR for molecular imaging of oral cancer surgery, human head and neck tumours were sectioned and stained for uPAR to evaluate the expression pattern compared to normal mucosa. Furthermore, metastatic oral squamous carcinoma cell line OSC-19 was used for targeting uPAR in in vivo mouse models. Using anti-uPAR antibody ATN-658, equipped with a multimodal label, the in vivo specificity was investigated and the optimal dose and time-window were evaluated.

RESULTS

All human oral cancer tissues expressed uPAR in epithelial and stromal cells. Hybrid ATN-658 clearly visualized tongue tumours in mice using either NIRF or SPECT imaging. Mean fluorescent TBRs over time were 4.3±0.7 with the specific tracer versus 1.7±0.1 with a control antibody. A significant difference in TBRs could be seen between 1nmol (150μg) and 0.34nmol (50μg) dose groups (n=4, p<0.05). Co-expression between BLI, GFP and the NIR fluorescent signals were seen in the tongue tumour, whereas human cytokeratin staining confirmed presence of malignant cells in the positive cervical lymph nodes.

CONCLUSION

This study shows the applicability of an uPAR specific multimodal tracer in an oral cancer model, combining SPECT with intraoperative guidance.

Down-regulation of SerpinB2 is associated with gefitinib resistance in non-small cell lung cancer and enhances invadopodia-like structure protrusions

The failure of targeted therapy due to the resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), such as gefitinib, is considered a major problem in the treatment of non-small cell lung cancer (NSCLC) patients. SerpinB2, a component of the urokinase plasminogen activator (uPA) system, has been recognized as a biomarker for the progression and metastasis of lung cancer. Nevertheless, the relationship between SerpinB2 and EGFR-TKI resistance has not been elucidated. Here, we report that SerpinB2 is down-regulated in gefitinib-resistant (H292-Gef) cells compared to gefitinib-sensitive (H292) cells. The low SerpinB2 levels in H292-Gef cells were also associated with an enhancement in invasiveness and increase in the length of invadopodia-like structures in the cells. The effect on invasiveness and gefitinib sensitivity was confirmed by knockdown and overexpression of SerpinB2. In addition, the possibility to overcome the resistance through the up-regulation of SerpinB2 was supported by employing an antitumor agent yuanhuadine (YD). Treatment with YD effectively elevated SerpinB2 levels and suppressed invasive properties in H292-Gef cells. Collectively, these findings demonstrate the prospective role of SerpinB2 as a novel biomarker for acquired gefitinib resistance and a potential target for NSCLC treatment.

Enhanced cell migration and apoptosis resistance may underlie the association between high SERPINE1 expression and poor outcome in head and neck carcinoma patients

High SERPINE1 expression is a common event in head and neck squamous cell carcinoma (HNSCC); however, whether it plays a role in determining clinical outcome remains still unknown. We studied SERPINE1 as a prognostic marker in two HNSCC patient cohorts. In a retrospective study (n = 80), high expression of SERPINE1 was associated with poor progression-free (p = 0.022) and cancer-specific (p = 0.040) survival. In a prospective study (n = 190), high SERPINE1 expression was associated with poor local recurrence-free (p = 0.022), progression-free (p = 0.002) and cancer-specific (p = 0.006) survival. SERPINE1 expression was identified as an independent risk factor for progression-free survival in patients treated with chemo-radiotherapy or radiotherapy (p = 0.043). In both patient cohorts, high SERPINE1 expression increased the risk of metastasis spread (p = 0.045; p = 0.029). The association between SERPINE1 expression and survival was confirmed using the HNSCC cohort included in The Cancer Genome Atlas project (n = 507). Once again, patients showing high expression had a poorer survival (p < 0.001). SERPINE1 over-expression in HNSCC cells reduced cell proliferation and enhanced migration. It also protected cells from cisplatin-induced apoptosis, which was accompanied by PI3K/AKT pathway activation. Downregulation of SERPINE1 expression had the opposite effect. We propose SERPINE1 expression as a prognostic marker that could be used to stratify HNSCC patients according to their risk of recurrence.

Urokinase plasminogen activator receptor (uPAR) and plasminogen activator inhibitor-1 (PAI-1) are potential predictive biomarkers in early stage oral squamous cell carcinomas (OSCC)

Oral squamous cell carcinoma (OSCC) is often associated with metastatic disease and a poor 5 year survival rate. Patients diagnosed with small tumours generally have a more favourable outcome, but some of these small tumours are aggressive and lead to early death. To avoid harmful overtreatment of patients with favourable prognosis, there is a need for predictive biomarkers that can be used for treatment stratification. In this study we assessed the possibility to use components of the plasminogen activator (PA) system as prognostic markers for OSCC outcome and compared this to the commonly used biomarker Ki-67. A tissue-micro-array (TMA) based immunohistochemical analysis of primary tumour tissue obtained from a North Norwegian cohort of 115 patients diagnosed with OSCC was conducted. The expression of the biomarkers was compared with clinicopathological variables and disease specific death. The statistical analyses revealed that low expression of uPAR (p = 0.031) and PAI-1 (p = 0.021) in the tumour cells was significantly associated with low disease specific death in patients with small tumours and no lymph node metastasis (T1N0). The commonly used biomarker, Ki-67, was not associated with disease specific death in any of the groups of patients analysed. The conclusion is that uPAR and PAI-1 are potential predictive biomarkers in early stage tumours and that this warrants further studies on a larger cohort of patients.

Polymorphisms in Kallikrein7 and 10 genes and oral cancer risks in Taiwan betel quid chewers and smokers

OBJECTIVES

We investigated the association between mRNA levels, polymorphisms of Kallikrein7 (KLK7) and Kallikrein10 (KLK10), and the development of oral squamous cell carcinoma (OSCC).

MATERIALS AND METHODS

We recruited 217 OSCC patients and 138 healthy controls. All were men, betel quid chewers, cigarette smokers, and Minnan ethnicity. Genotyping was performed using a TaqMan probe genotyping assay. Gene expression levels were determined using real-time polymerase chain reactions (PCRs) for 20 pairs of cancerous and non-cancerous tissues.

RESULTS

Kallikrein10 rs3745535G>T polymorphisms were significantly associated with OSCC development [adjusted OR (AOR) = 1.62, 95% CI = 1.02-2.59], but KLK7 polymorphisms were not. The KLK7 rs10581213(wt/ins + ins/ins) genotypes were significantly associated with early-stage cancer (AOR = 0.34, 95% CI = 0.14-0.78), but KLK10 polymorphisms were not. Relative expression analysis indicated that an increase in KLK7 and KLK10 mRNA levels was found in cancerous tissues (2(-ΔΔCT) = 25.23 ± 8.85 and 10.89 ± 4.97, respectively). A significantly higher level of KLK7 was expressed in early-stage cancer with the rs10581213(wt/ins + ins/ins) genotypes, but there was no significant difference in the mRNA levels of KLK7 and KLK10 between early- and advanced-stage cancers.

CONCLUSIONS

This is the first correlation of OSCC with KLK10 rs3745535G>T polymorphisms. Early-stage OSCC and high KLK7 mRNA levels were correlated with the rs10581213(wt/ins + ins/ins) genotypes. More studies with large sample sizes are needed to verify our findings.

Loss of claudin-7 is a negative prognostic factor for invasion and metastasis in oral squamous cell carcinoma

Claudin-7 belongs to the claudin family, which consists of 24 subtypes of essential tight junction (TJ) integral membrane proteins with molecular weights of 20-27 kDa. We investigated the interrelationship between clinicopathological findings and claudin-7 expression in oral squamous cell carcinoma (OSCC). Using immunohistochemical techniques to examine the expression levels of claudin-7 in 67 cases of OSCC, claudin-7 expression was detected in 35 (52.2%) of the 67 cases. We also compared the clinicopathological features of the OSCC cases with claudin-7 expression levels. Moreover, six cell lines with various invasive properties were investigated in vitro to compare mRNA and protein levels of claudin-7 using reverse transcription-polymerase chain reaction (RT-PCR) and the western blotting method. Decreased claudin-7 expression correlated significantly with T-category (p<0.05), lymph node metastasis (p<0.01), and mode of invasion (p<0.001). Patients with positive claudin-7 expression had a significantly better prognosis (p<0.05). Claudin-7 protein and mRNA levels were lower in the HOC313 and TSU cells, which have higher invasive potentials compared with other cell lines. These results suggest that loss of claudin-7 expression is associated closely with invasion and lymph metastasis and is an unfavorable prognostic factor in patients with OSCC.

Urinary-type plasminogen activator receptor (uPAR) modulates oral cancer cell behavior with alteration in p130cas

Oral cavity cancer is among the most frequently diagnosed cancers worldwide and urinary-type plasminogen activator receptor (uPAR) is clinically associated with more invasive tumors and enhanced lymph node metastasis. We seek to further elucidate the mechanism of by which uPAR promotes cell aggressiveness in the unique context of oral squamous cell carcinoma (OSCC). The contribution of uPAR expression to aggressive cellular behavior of OSCC was examined using in vitro cellular models wherein the expression of uPAR was manipulated and in a human OSCC tissue microarray. Results show altered adhesion, motility, and invasion in cells that overexpress uPAR relative to vector control cells. Distinct alterations of focal adhesion protein expression and phosphorylation, including p130cas and paxillin were observed, suggestive of enhanced focal adhesion turnover. Immunohistochemical analysis of microarrayed human OSCC revealed a significant correlation between uPAR and p130cas expression. The non-receptor protein tyrosine kinase c-Src was responsible for the phosphorylation of p130cas in response to uPAR/α3β1/laminin-5 engagement. Further downstream, the Rho family GTPase Cdc42, but not Rac1, was activated, suggesting a pathway leading to actin reorganization, filopodial protrusion and enhanced motility in uPAR overexpressing oral cancer cells. These data shed light on a molecular mechanism whereby acquisition of uPAR expression may modulate OSCC invasive activity through alteration of focal adhesion dynamics.

Clinical utility of level-of-evidence-1 disease forecast cancer biomarkers uPA and its inhibitor PAI-1

The prognostic and/or predictive value of the cancer biomarkers, urokinase-type plasminogen activator (uPA) and its inhibitor (plasminogen activator inhibitor [PAI]-1), determined by ELISA in tumor-tissue extracts, was demonstrated for several cancer types in numerous clinically relevant retrospective or prospective studies, including a multicenter breast cancer therapy trial (Chemo-N0). Consequently, for the first time ever for any cancer biomarker for breast cancer, uPA and PAI-1 have reached the highest level of evidence, level-of-evidence-1. At present, two other breast cancer therapy trials, NNBC-3 and Plan B, also incorporating uPA and PAI-1 as treatment-assignment tools are in effect. Furthermore, small synthetic molecules targeting uPA are currently in Phase II clinical trials in patients afflicted with advanced cancer of the ovary, breast or pancreas.

Epigenetic alterations of the SERPINE1 gene in oral squamous cell carcinomas and normal oral mucosa

A high level of plasminogen activator inhibitor-1 (PAI-1 or SERPINE1) in tumor extracts is a marker of a poor prognosis in human cancers, including oral carcinomas. However, the mechanisms responsible for the upregulation of PAI-1 in cancers remain unclear. Investigating specific PAI-1 expressing cells in oral carcinomas by immunohistochemistry, we found that PAI-1 was expressed in 18 of the 20 patients, mainly by cancer cells. Two showed PAI-1 positive stromal cells surrounding the tumor areas and five showed PAI-1 positive cells in tumor-adjacent normal epithelium. By real-time RT-PCR analysis, 17 of 20 patients with oral carcinoma were found to have between 2.5- and 50-fold increased tumor PAI-1 mRNA level, as compared with the matched tumor-adjacent normal tissues. The PAI-1 mRNA level in connective tissues from 15 healthy volunteers was similar to the level in tumor-adjacent normal tissues, but the level in epithelium was 5- to 10-fold lower. Analyzing DNA methylation of 25 CpG sites within 960 bp around the transcription initiation site of the SERPINE1 gene by bisulfite sequencing, we did the surprising observation that both tumors and tumor-adjacent normal tissue had a significant level of methylation, whereas there was very little methylation in tissue from healthy volunteers, suggesting that tumor-adjacent normal tissue already contains transformation-associated epigenetic changes. However, there was no general inverse correlation between PAI-1 mRNA levels and SERPINE1 gene methylation in all tissues, showing that CpG methylation is not the main determinant of the PAI-1 expression level in oral tissue.

Inhibitory effect of curcumin on motility of human oral squamous carcinoma YD-10B cells via suppression of ERK and NF-kappaB activations

Oral squamous cell carcinomas (OSCCs) are characterized by a marked propensity for local invasion, so the identification of agents inhibiting the onset and progression of OSCC has recently gained interest. Here, we found that curcumin inhibited cell proliferation and motility with decreased activities of matrix metalloproteinase (MMP)-2/9 and decreased mRNA expressions of urokinase-type plasminogen activator (uPA) and its receptor uPAR in the highly invasive human YD-10B OSCC cells. Western blot analysis showed that curcumin inhibited the activation of MAP kinases (especially ERK) and NF-kappaB, which are involved in the transcriptional regulation of proteolytic enzymes. In conclusion, curcumin is one of the strong phytochemicals with antimotility activity of OSCC; the inhibitory effect of curcumin on the motility of YD-10B cells could result from its potential to inhibit the activation of ERK/MAP kinase and NF-kappaB that consequently down-regulate the mRNA expressions and activities of proteolytic enzymes such as uPA and MMP-2/9.

Urinary-type plasminogen activator receptor/alpha 3 beta 1 integrin signaling, altered gene expression, and oral tumor progression

Oral squamous cell carcinoma (OSCC) has 50% 5-year survival rate, highlighting our limited understanding of the molecular events that contribute to disease progression. Microarray analyses of primary oral tumors have identified urinary-type plasminogen activator (uPA) and its receptor (uPAR) as key genes associated with human OSCC progression. The uPAR functions as both a proteinase receptor and an integrin ligand, modifying proteolysis, migration, integrin signaling, and cellular transcription. In the current study, uPAR expression levels were modified in OSCC cells followed by analysis of tumor growth in an in vivo orthotopic xenograft model and by transcriptional profiling. Overexpression of uPAR resulted in more infiltrative and less differentiated tumors, with ill-defined borders, cytologic atypia, and enhanced vascularity. Analysis of serial sections of both murine experimental tumors and microarrayed human OSCC showed a statistically significant association between uPAR and alpha(3) integrin colocalization in areas exhibiting extracellular signal-regulated kinase phosphorylation, suggesting that uPAR/alpha(3) integrin interaction potentiates extracellular signal-regulated kinase signaling in vivo. This is supported by cDNA microarray analysis, which showed differential expression of 148 genes (113 upregulated and 35 downregulated). Validation of gene expression changes in human OSCC using immunohistochemistry and quantitative real-time PCR showed increased growth factors, proteinases/inhibitors, and matrix components in uPAR-overexpressing tumors. Together, these results support a model wherein increased uPAR expression promotes alpha(3)beta(1) integrin association, resulting in increased mitogen-activated protein kinase signaling and transcriptional activation, leading to the formation of more aggressive tongue tumors. This combined approach has efficacy to identify additional biomarkers and/or prognostic indicators associated with aggressive human OSCC.

Significance of stromal desmoplasia and myofibroblast appearance at the invasive front in squamous cell carcinoma of the oral cavity

BACKGROUND

Tumor invasion involves complex interactions between tumor and stromal cells. We examined the extent of connective tissue in the tumor stroma and whether myofibroblasts play a role in assisting cancer invasion and metastasis.

METHODS

Biopsy materials from 84 patients with oral squamous cell carcinoma (SCC) were used. We compared data from intrastromal collagen fibers using Azan staining, immunohistochemical identification of myofibroblasts by cytoskeletal markers, alpha-smooth muscle actin, vimentin, desmin, and clinicopathological parameters. Clinical outcome was compared by 5-year survival rate.

RESULTS

There were high levels of stromal collagen fibers in invasive tumors. Myofibroblast appearance increased with increasing tumor invasiveness. Lymph node metastasis occurred more frequently in the myofibroblast-positive group, and the survival rate was significantly poorer in this group.

CONCLUSIONS

Fibrous stroma in SCC appeared to have a desmoplastic response. However, an independent invasive mechanism may regulate the stroma, with tumor desmoplasia occurring in highly developed, invasive tumors.

RNAi targeting urokinase-type plasminogen activator receptor inhibits metastasis and progression of oral squamous cell carcinoma in vivo

It has been admitted that urokinase-type plasminogen activator receptor (u-PAR) is overexpressed in many human malignant tumors including oral squamous cell carcinoma (OSCC) and plays an important role in a variety of cancer key cellular events as a versatile signaling orchestrator. In our study, a retroviral vector expressing u-PAR-specific siRNA was injected into OSCC xenografts of nude mice to observe its inhibitory effects on OSCC. Our data demonstrate that siRNA targeting u-PAR markedly suppressed tumor growth, reduced the expression of proliferation-related gene, Ki-67 and increased cell apoptosis, accompanying with the efficient and specific inhibition of endogenous u-PAR expression in OSCC. More importantly, the mRNA and protein expression of MMP-2, MMP-9, VEGF-C, VEGF-D and VEGFR-3 that are intimately involved in oral cancer invasion and metastasis, was simultaneously downregulated significantly as determined by quantitative real-time RT-PCR, Western blot and immunohistochemistry; and Gelatin and fibrin zymography showed that MMP-9, MMP-2 and u-PA enzymatic activities were significantly reduced in u-PAR-specific siRNA group, compared to those in control groups. In addition, the expression of MDR-1 gene related to drug resistance was obviously inhibited by silencing of u-PAR. These findings suggest that RNAi targeting u-PAR could effectively inhibit the metastasis and progression of OSCC in vivo. Thus, it may be used as a potent and specific therapy for oral cancer, especially in inhibiting and preventing cancer cell invasion and metastasis.

Multiple kallikrein (KLK 5, 7, 8, and 10) expression in squamous cell carcinoma of the oral cavity

Oral squamous cell carcinoma (OSCC) represents 3% of all cancer deaths in the U.S. and is ranked one of the top 10 cancers worldwide. The 5-year survival rate has remained at a low 50% for the past several decades, necessitating discovery of novel biomarkers of aggressive disease and therapeutic targets. As overexpression of urinary type plasminogen activator and receptor (uPA/R) in OSCC is associated with malignant progression and poor outcome, cell lines were generated with either overexpression (SCC25-uPAR+) or silencing (SCC25-uPAR-KD) of uPAR. As SCC25-uPAR+ tumors behaved more aggressively both in vitro and in vivo, comparative cDNA microarray analysis was used to identify additional genes that may be associated with aggressive tumors. Four members of the human tissue kallikrein family (KLK 5, 7, 8, and 10) were identified and real-time RT-PCR (qPCR) was used to verify and quantify gene expression. qPCR analysis revealed 2.8-, 5.3-, 4.0-, and 3.5-fold increases in gene expression for KLK5, 7, 8, and 10, respectively, in SCC25-uPAR+ versus SCC25-uPAR-KD. Immunohistochemical analysis demonstrated strong reactivity for KLKs 5, 7, 8 and 10 in both orthotopic murine tumors and human OSCC tissues. Control experiments show lack of reactivity against KLK3 (prostate specific antigen). These results demonstrate that kallikreins 5, 7, 8, and 10 are abundantly expressed in human OSCC and may be implicated in malignant progression.

Management of the N0 neck in oral squamous cell carcinoma

Oral squamous cell carcinoma (SCC) has an unpredictable capacity to metastasize to the neck, an event that dramatically worsens prognosis. Metastasis occurs even in earlier stages when no neck lymph node involvement is clinically detectable (N0). Management of the N0 neck, namely when and how to electively treat, has been debated extensively. This article presents the controversies surrounding management of the N0 neck, and the benefits and pitfalls of different approaches used in evaluation and treatment. As current methods of assessing the risk for occult metastasis are insufficiently accurate and prone to underestimation of actual risk, and because selective neck dissection (SND) is an effective treatment and has minimal long-term detriment to quality of life, the authors believe that all patients who have oral SCC, excluding lip SCC, should be prescribed elective treatment of the neck lymphatics. However, this opinion remains controversial. Because of the morbidity of radiation therapy and because treatment of the primary tumor is surgical, elective neck dissection is the preferred treatment. In deciding the extent of the neck dissection, several retrospective studies and one randomized clinical trial have shown SND of levels I through III to be highly efficacious.

Prognostic value analysis of urokinase-type plasminogen activator receptor in oral squamous cell carcinoma: an immunohistochemical study

Background

Oral squamous cell carcinoma (OSCC) represents the most common oral malignancy. Despite recent advances in therapy, up to 50% of the cases have relapse and/or metastasis. There is therefore a strong need for the identification of new biological markers able to predict the clinical behaviour of these lesions in order to improve quality of life and overall survival. Among tumour progression biomarkers, already known for their involvement in other neoplasia, a crucial role is ascribed to the urokinase-type plasminogen activator receptor (uPAR), which plays a multiple role in extracellular proteolysis, cell migration and tissue remodelling not only as a receptor for the zymogen pro-uPA but also as a component for cell adhesion and as a chemoattractant. The purpose of this study was to gain information on the expression of uPAR in OSCC and to verify whether this molecule can have a role as a prognostic/predictive marker for this neoplasia.

Methods

In a retrospective study, a cohort of 189 OSCC patients was investigated for uPAR expression and its cellular localization by immunohistochemistry. As standard controls, 8 normal oral mucosal tissues free of malignancy, obtained from patients with no evidence or history of oral cavity tumours, were similarly investigated. After grouping for uPAR expression, OSCCs were statistically analyzed for the variables age, gender, histological grading (G), tumour size, recurrence, TNM staging and overall survival rate.

Results

In our immunohistochemical study, 74 cases (39.1%) of OSCC showed a mostly cytoplasmic positivity for uPAR, whereas 115 were negative. uPAR expression correlated with tumour differentiation grade and prognosis: percentage of positive cases was the greatest in G3 (70.4%) and patients positives for uPAR expression had an expectation of life lower than those for uPAR negatives.

Conclusion

The results obtained in this study suggest a role of uPAR as a potential biomarker useful to identify higher risk subgroups of OSCC patients.

Revisiting the biological roles of PAI2 (SERPINB2) in cancer

Tumour expression of the urokinase plasminogen activator correlates with invasive capacity. Consequently, inhibition of this serine protease by physiological inhibitors should decrease invasion and metastasis. However, of the two main urokinase inhibitors, high tumour levels of the type 1 inhibitor actually promote tumour progression, whereas high levels of the type 2 inhibitor decrease tumour growth and metastasis. We propose that the basis of this apparently paradoxical action of two similar serine protease inhibitors lies in key structural differences controlling interactions with components of the extracellular matrix and endocytosis-signalling co-receptors.

RNAi-mediated downregulation of urokinase plasminogen activator receptor inhibits proliferation, adhesion, migration and invasion in oral cancer cells

RNA interference (RNAi) has emerged as an effective method to target specific genes for silencing. Overexpression of urokinase-type plasminogen activator receptor (uPAR) has been implicated in progression and metastasis of oral cancer. In our study, RNAi was introduced to downregulate the expression of uPAR in the highly malignant oral squamous cell carcinoma (OSCC) cells. Our data demonstrated that siRNA targeting of uPAR leads to the efficient and specific inhibition of endogenous uPAR mRNA and protein expression as determined by quantitative real-time RT-PCR and Western blotting. Furthermore, simultaneous silencing of uPAR resulted in a dramatic reduction of tumor cell proliferation activity, adhesion, migration and invasion in vitro compared to the controls. These findings provide further evidence for the involvement of uPAR in a variety of cancer key cellular events as a versatile signaling orchestrator, and suggest that RNAi-directed targeting of uPAR can be used as a potent and specific therapeutic tool for the treatment of oral cancer, especially in inhibiting and/or preventing cancer cell invasion and metastasis.

Urinary-type plasminogen activator (uPA) and its receptor (uPAR) in squamous cell carcinoma of the oral cavity

OSCC (oral squamous cell carcinoma) is the most common oral malignancy and is estimated to affect approx. 350000 new patients worldwide this year. OSCC is characterized by a high degree of morbidity and mortality, as most patients exhibit local, regional and distant metastasis at the time of diagnosis. Recent genome-wide screening efforts have identified the serine proteinase uPA (urinary-type plasminogen activator, also known as urokinase) as a strong biomarker for prediction of poor disease outcome and a key candidate for molecular classification of oral neoplasms using a 'gene signature' approach. The proteinase uPA binds a surface-anchored receptor designated uPAR (uPA receptor), focalizing proteolytic activity to the pericellular milieu. Furthermore, uPA-uPAR can interact with transmembrane proteins to modify multiple signal transduction pathways and influence a wide variety of cellular behaviours. Correlative clinical data show elevated uPA-uPAR in oral tumour tissues, with tumours exhibiting high levels of both uPA and uPAR as the most invasive. Combined in vitro, pre-clinical and clinical data support the need for further analysis of uPA-uPAR as a prognostic indicator as well as a potential therapeutic target in OSCC.

Plasminogen activator system in oral squamous cell carcinoma

BACKGROUND

The plasminogen activator system consists of two plasminogen activators, urokinase (uPA) and tissue (tPA); PA inhibitors (PAI-1, and -2), and a cell surface receptor for uPA (uPAR). The plasminogen activator system is involved at many stages of the metastatic cascade, including matrix remodelling, cell proliferation, and migration.

AIMS

To compare tissue concentrations of the components of the plasminogen activator system in paired tumour tissue and normal tissue in patients with oral squamous cell carcinoma, and to correlate these with the histopathological grading of the tumour.

METHODS

Thirty-eight paired tissue samples were analysed by enzyme-linked immunosorbent assays (ELISA; ng/mg protein) for uPA, tPA, uPAR, PAI-1, and PAI-2.

RESULTS

Concentrations of uPA, uPAR, PAI-1, and PAI-2 were significantly higher in tumour than in normal oral tissue (median in uPAR tumour 1.6 (range; 0.1-7.5) ng/mg protein; normal=0.2 (0-2.3), p<0.05). There were strong correlations between the concentrations of certain components of the plasminogen activator system in particular between uPA, uPAR, and PAI-1 (p<0.05). Tissue concentrations of some components of the plasminogen activator system correlated with clinical and pathological indexes of aggression of tumours, including differentiation and T-stage.

CONCLUSION

The relation between components of the plasminogen activator system, in particular uPA, uPAR, and PAI-1 in invasion, metastasis, prognosis, and survival, requires further investigation in oral squamous cell carcinomas.

Prognostic value of plasminogen activator inhibitor-1 in head and neck squamous cell carcinoma

BACKGROUND

Tumor cell biological factors, such as urokinase plasminogen activator (uPA) and its inhibitor plasminogen activator inhibitor-1 (PAI-1), cathepsin D, and c-myc play a role in tumor invasion, metastasis, and proliferation. In this study, the prognostic importance of these factors in patients with primary head and neck squamous cell carcinoma (HNSCC) was evaluated and correlated with clinicopathologic variables.

METHODS

In 46 paired primary tumors and normal tissues, levels of uPA, PAI-1, cathepsin D, and c-myc amplification were determined. The clinical follow-up was over 10 years. Relationships between cell biological factors and patient and tumor characteristics were studied by the Mann-Whitney test. The Cox proportional hazard model was used for univariate and multivariate analysis.

RESULTS

In this study, only a high level of PAI-1 was associated with a significantly shorter disease-free survival (p < .01). PAI-1 levels were higher in tumors with perineural invasion (p < .01). Both PAI-1 and uPA levels were higher in patients who smoked (p < .01 and p = .02). In univariate analysis, smoking (p= .04), excessive alcohol intake (p = .02), perineural invasion (p = .001), and vaso-invasion (p = .009) were associated with a shorter disease-free survival. The only factor related to overall survival was perineural invasion (p = .045). The combination of a high PAI-1 level and perineural invasion appeared to be a significant predictor of a shorter disease-free interval (p = .01).

CONCLUSION

PAI-1 may present a novel prognostic factor for patients with HNSCC. Perineural invasion and PAI-1 level combined seemed to be prognostic for disease-free survival.

Expression of urokinase-type plasminogen activator receptor is correlated with metastases of lingual squamous cell carcinoma

Lingual squamous cell carcinoma is common and the survival rate is relatively low. The invasion of cancer cells from the primary tumour into the surrounding tissue is an early step in the process of metastasis and urokinase-type plasminogen activator receptor (uPAR) is a vital mediator of cellular migration in some carcinomas. By binding urokinase-type plasminogen activator, uPAR localises proteolytic activity to the leading edge of the cells, thereby facilitating cellular migration and penetration through tissue boundaries. uPAR also binds directly to vitronectin and associates with integrins within the plasma membrane, which alters the strength of cellular adhesion. In this study we used reverse transcription polymerase chain reaction, immunocytochemistry, and Western-blot to examine the expression of uPAR mRNA and protein in Ts and Tca 8113 cell lines of lingual squamous cell carcinoma and in normal oral mucosal cells. uPAR mRNA and protein were expressed in Ts cells, but not in Tca 8113 cells or in normal oral epithelial cells. Ts cells have higher metastatic potential than Tca 8113 cells. The results suggest that uPAR has an important role in the aggressiveness of lingual squamous cell carcinoma.

Targeting urokinase-type plasminogen activator and its receptor for cancer therapy

Cancer invasion and metastasis are highly complex processes and a serine protease urokinase-type plasminogen activator/urokinase-type plasminogen activator receptor system has been postulated to play a central role in the mediation of cancer progression. Of note, malignant tumor urokinase-type plasminogen activator and urokinase-type plasminogen activator receptor levels have been found to vary considerably, and to be related to patient prognosis. In mouse models, the urokinase-type plasminogen activator/urokinase-type plasminogen activator receptor system has been studied extensively as a target for anticancer therapy using a variety of approaches. In this review, we discuss the advances in the various modalities that have been used to target the urokinase-type plasminogen activator/urokinase-type plasminogen activator receptor system, including protein-based and peptide-based drugs, antisense therapy, and RNA interference technology. In particular, preclinical mouse model studies that used human tumor xenografts are reviewed.

Expression of plasminogen activator inhibitor-1, urokinase receptor and laminin γ-2 chain is an early coordinated event in incipient oral squamous cell carcinoma

Cancer cell invasion is facilitated by extracellular matrix degrading proteases such as plasmin. We have studied the expression of plasminogen activator inhibitor-1 (PAI-1) and urokinase receptor (uPAR) together with the gamma2-chain of laminin-5 (lam-gamma2) by immunohistochemistry in 20 cases with incipient oral squamous cell carcinoma (SCC). PAI-1-positive neoplastic cells located at the tip of the putative invasive front of grade 1 (incipient) carcinoma were seen in 16 of the 20 cases (75%), whereas adjacent normal and dysplastic epithelium was PAI-1-negative. Clusters of putative invasive neoplastic cells located in the lamina propria were PAI-1-positive in areas with grade 2 incipient carcinoma as were invasive cancer cells in areas of grade 3-4 invasive carcinoma. uPAR immunoreactivity was strongly expressed in numerous stromal cells in the carcinoma area in all 20 lesions, while a few uPAR-positive stromal cells were found in areas with normal and dysplastic epithelium. uPAR-positive neoplastic cell islands located at the front of the lesions were seen in 15 of the 20 cases. The expression pattern of lam-gamma2 was very similar to that of PAI-1; however, lam-gamma2-positive neoplastic cells were only detected in 11 of the 20 cases (55%) in areas of grade 1 incipient carcinoma. Direct comparison of the 3 components revealed colocalization in neoplastic cell islands in both incipient and invasive SCC. Our results suggest that PAI-1 is a novel potential marker of initial invasion in oral SCC, and that the coordinated expression of PAI-1 with uPAR and lam-gamma2 sustain the features of the early invasive cancer cells.

Inhibition of invasion and metastasis in oral cancer by targeting urokinase-type plasminogen activator receptor

There have been reports of strong correlations between poor prognosis in various cancers and concomitant expression of urokinase-type plasminogen activator (uPA) and its surface receptor (uPAR). We and others have previously shown that the uPA system plays a significant role in a subset of head and neck squamous cell carcinoma. In the present study, we found that uPAR is required for invasion and metastasis of highly malignant oral cancer cells (OSC-19). Treating OSC-19 cells with antisense oligonucleotides (AS) targeting uPAR resulted in a dramatic decrease of uPAR mRNA expression. Furthermore, pretreatment with AS or siRNA targeting uPAR inhibited progression of OSC-19 cells in experimental models. These results suggest that overexpression of uPAR increases the invasiveness and metastasis of OSC-19 cells, and that uPAR is a promising therapeutic target for regulation of progression of oral cancer.

Urokinase gene 3'-UTR T/C polymorphism is associated with oral cancer

Urokinase is thought to be involved in the formation of oral cancer, although there is a lack of genetic evidence. Our aim was to study single nucleotide polymorphisms in order to investigate the possibility. A total of 130 oral cancer patients and 105 controls were studied. Polymerase chain reaction (PCR) based restriction analysis was used to identify the C/T polymorphism of the urokinase gene, which is located on the 3'-untranslated region (3'-UTR) of chromosome 10. There was a significant difference in the distribution of the urokinase gene 3'-UTR C/T polymorphism frequency between cancer patients and the normal control group (P < 0.05). The "T" allele was prominent in the cancer group. The odds ratio for the risk of the "T" allele in cancer patients was 2.71 (95% CI = 1.325 approximately 5.562). The cancer patients were further categorized according to gender and whether or not they were habitual smokers or betel nut chewers. These clinical parameters were then compared with tumor cell differentiation and tumor progression. No significant differences were found. Therefore, the urokinase gene 3'-UTR "T" allele is associated with oral cancer and may play a role in oral cancer formation. However, we did not find the relationship between tumor progression and this polymorphism.

Genome-wide profiling of oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a common malignancy, the incidence of which is particularly high in some Asian countries due to the geographically linked areca quid (AQ) chewing habit. In this study, array-based comparative genomic hybridization was used to screen microdissected OSCCs for genome-wide alterations. The highest frequencies of gene gain were detected for TP63, Serpine1, FGF4/FGF3, c-Myc and DMD. The highest frequencies of deletion were detected for Caspase8 and MTAP. Gained genes, classified by hierarchical clustering, were mainly on 17q21-tel; 20q; 11q13; 3q27-29 and the X chromosome. Among these, gains of EGFR at 7p, FGF4/FGF3, CCND1 and EMS1 at 11q13, and AIB1 at 20q were significantly associated with lymph node metastasis. The genomic profiles of FHIT and EXT1 in AQ-associated and non-AQ-associated OSCCs exhibited the most prominent differences. RT-PCR confirmed the significant increase of TP63 and Serpine1 mRNA expression in OSCC relative to non-malignant matched tissue. A significant increase in Serpine1 immunoreactivity was observed from non-malignant matched tissue to OSCC. However, there was no correlation between the frequent genomic loss of Caspase 8 and a significant decrease in Caspase8 expression. These data demonstrate that genomic profiling can be useful in analysing pathogenetic events involved in the genesis or progression of OSCC.

Staging of the neck in patients with head and neck squamous cell cancer: Imaging techniques and biomarkers

Regional metastasis is an important factor in the treatment and prognosis of head and neck cancer patients. Current treatment strategies rely on staging based on the still limited accuracy of imaging techniques to detect regional metastases. If more certainty about the nodal status could be attained, treatment strategies concerning the neck could be better adjusted to the individual patient. The continuing improvement of established imaging techniques and the introduction of new imaging modalities will add to better staging. Moreover, the additional use of biomarkers studied on a protein, RNA or DNA level may provide even better information about the chance of occult nodal metastasis in head and neck cancer patients.

The mRNA profile of genes in betel quid chewing oral cancer patients

Oral cancer is one of the most common types of human cancer in the world. Although the risk factors for oral cancer are well-recognized in different countries, the molecular mechanism responsible for this malignancy remains elusive particularly in the countries where betel quid chewing is prevalent. The cDNA microarray analysis was used to analyse the mRNA expression patterns of 1177 genes in ten oral cancer patients with betel quid chewing history. Eighty-four genes involving cell adhesion, cell shape, growth, apoptosis, angiogenesis, metastasis, and metabolism were deregulated. Although the expression profile of these genes was shared by certain clinical patients, there was no significant association of the expression profile with clinical staging. Functional implication of four validated genes including caspase-1, STAT-1, COX-2 and pleiotrophin was discussed. This study provides pilot data for understanding the pathogenesis of oral cancer in countries like Taiwan where betel quid chewing is prevalent.

Inhibition of the invasion capacity of carcinoma cells by WX-UK1, a novel synthetic inhibitor of the urokinase-type plasminogen activator system

The overall survival rate of patients suffering from carcinomas has remained poor and nearly unchanged over the last decades. This is mainly due to the so-called minimal residual disease, i.e., remaining tumor cells that overcome surgery and/or radiotherapy and are the cause of locoregional and distant metastases. To metastasize, tumor cells take advantage of proteases to invade and remodel surrounding tissues. Here, we analyzed the efficiency of WX-UK1, a novel 3-amidinophenylalanine-based inhibitor of the uPA system, at inhibiting the invasive capacity of carcinoma cells. First, uPAR expression was characterized in different carcinoma cell lines, including SCCHN, breast and cervical carcinoma. Thereafter, the invasive potential of these cell lines was determined using Matrigel invasion chambers and a spheroid cocultivation model with human fibroblasts. uPAR expression levels correlated positively with invasion capacity, which could be significantly inhibited by WX-UK1. A decrease of tumor cell invasion by up to 50% was achieved in both models with the SCCHN line FaDu and the cervical carcinoma line HeLa after treatment with WX-UK1. Thus, our results demonstrate the potential of WX-UK1 in vitro as a promising adjuvant antimetastatic therapy of carcinomas.

Genomic dissection for characterization of cancerous oral epithelium tissues using transcription profiling

Genome-wide and high-throughput functional genomic tools offer the potential of identifying disease-associated genes and dissecting disease regulatory patterns. There is a need for a set of systematic bioinformatic tools that handles efficiently a large number of variables for extracting biological meaning from experimental outputs. We present well-characterized statistical tools to discover genes that are differentially expressed between malignant oral epithelial and normal tissues in microarray experiments and to construct a robust classifier using the identified discriminatory genes. Those tools include Wilks' lambda score, error rate estimated from leave-one out cross-validation (LOOCV) and Fisher Discriminant Analysis (FDA). High Density DNA microarrays and Real Time Quantitative PCR were employed for the generation and validation of the transcription profile of the oral cancer and normal samples. We identified 45 genes that are strongly correlated with malignancy. Of the 45 genes identified, six have been previously implicated in the disease, and two are uncharacterized clones.

Loss of adhesion-regulated proteinase production is correlated with invasive activity in oral squamous cell carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC) is the most common malignancy of the oral cavity. However, the cellular and biochemical factors that underlie locoregional and distant spread of the disease are poorly understood. Invasion of OSCC requires multiple cellular events including dissolution of cell-cell junctions, basement membrane attachment, extracellular matrix proteolysis, and migration.

METHODS

We evaluated these properties in vitro using premalignant gingival keratinocytes (ppl26) and two OSCC lines (SCC15 and SCC68). Expression of adhesion molecules integrins and cadherins, cytoplasmic intermediate filaments (IF) vimentin and keratin as well as matrix degrading proteins were evaluated. Moreover, regulation of protease production by adhesion molecules was tested.

RESULTS

All cell lines contained comparable levels of the epithelial cell-cell adhesion molecule, E-cadherin. Differential expression of cytoplasmic IF was evident between premalignant pp126 cells and OSCC cell lines. Expression levels of the alpha3beta1 integrin, utilized for attachment to laminin-5 and other matrix proteins, was high in SCC68 cells, moderate in SCC15 cells, and low in ppl26 cells. alpha3beta1 integrin clustering up-regulates expression of urinary-type plasminogen activator (uPA) in ppl26 cells via a mechanism involving ERK activation. Both ppl26 and SCC15 cells were responsive to alpha3beta1 clustering, resulting in enhanced uPA expression. However, basal uPA levels were high in SCC68 cells and integrin clustering did not further stimulate uPA production. ERK was constitutively activated in SCC68 cells and treatment of cells with an inhibitor of ERK activation (PD98059) reduced uPA expression. Consistent with the enhanced proteolytic potential, SCC68 cells readily penetrated Matrigel and invasion was blocked by an anticatalytic uPA antibody.

CONCLUSIONS

These data suggest that loss of adhesion-regulated proteinase production may lead to elevated pericellular proteinase activity and coincident alterations in cytoskeletal IF protein expression, thereby contributing to the invasive potential of OSCC.