Prognostic value of the urokinase-type plasminogen activator, and its inhibitors and receptor in breast cancer patients

Unlocking the potential of oncology biomarkers: advancements in clinical theranostics

INTRODUCTION

Cancer biomarkers have revolutionized the field of oncology by providing valuable insights into tumor changes and aiding in screening, diagnosis, prognosis, treatment prediction, and risk assessment. The emergence of "omic" technologies has enabled biomarkers to become reliable and accurate predictors of outcomes during cancer treatment.

CONTENT

In this review, we highlight the clinical utility of biomarkers in cancer identification and motivate researchers to establish a personalized/precision approach in oncology. By extending a multidisciplinary technology-based approach, biomarkers offer an alternative to traditional techniques, fulfilling the goal of cancer therapeutics to find a needle in a haystack.

SUMMARY AND OUTLOOK

We target different forms of cancer to establish a dynamic role of biomarkers in understanding the spectrum of malignancies and their biochemical and molecular characterization, emphasizing their prospective contribution to cancer screening. Biomarkers offer a promising avenue for the early detection of human cancers and the exploration of novel technologies to predict disease severity, facilitating maximum survival and minimum mortality rates. This review provides a comprehensive overview of the potential of biomarkers in oncology and highlights their prospects in advancing cancer diagnosis and treatment.

Prognostic significance of VEGF and components of the plasminogen activator system in endometrial cancer

Objective

The plasminogen activator system (PAS) and vascular endothelial growth factor (VEGF) are important in the carcinogenesis and play a key role in cancer invasion and mediating metastasis of carcinomas. The aim of the study was to evaluate the correlation of serum levels of VEGF and components of the PAS with clinicopathological risk factors and outcome in patients with endometrial cancer (EC).

Methods

Preoperative blood was collected from 173 patients treated for EC between 1999 and 2009. Serum concentrations of VEGF, urokinase plasminogen activator (uPA) tissue plasminogen activator (tPA), plasminogen activator inhibitor type-1 (PAI-1) and -2 (PAI-2) were assessed by enzyme-linked immunosorbent assays (ELISA).

Results

Serum levels of VEGF and components of the PAS were significantly associated with stage of the disease, tumor histology, tumor grade, myometrial invasion (MI), presence of lymphovascular space invasion (LVSI) and lymph node metastases (LNM). Preoperative serum levels of PAI-1 and -2 and tPA were higher in patients who experienced a recurrence than in patients who remained disease free (p < 0.01). PAI-1 and -2 and tPA were significantly independent prognostic factors for DFS with a HR of 3.85 (95% CI 1.84–8.07), 3.90 (95% CI 1.75–8.66) and 2.53 (95% CI 1.16–5.55), respectively. PAI-1 and tPA turned out to be independent prognostic factors for OS, with a HR of 2.09 (95% CI 1.08–4.05) and 2.16 (95% CI 1.06–4.44), respectively.

Conclusion

Serum levels of VEGF and components of the PAS at primary diagnosis were associated with well-known clinicopathological risk factors such as; FIGO stage, tumor histology, tumor grade, MI, LVSI and LNM. High concentrations of PAI-1 and-2 and tPA are independent factors for poor prognosis in patients with endometrial cancer.

Post-injury Nose-to-Brain Delivery of Activin A and SerpinB2 Reduces Brain Damage in a Mouse Stroke Model

Synaptic NMDA receptors activating nuclear calcium-driven adaptogenomics control a potent body-own neuroprotective mechanism, referred to as acquired neuroprotection. Viral vector-mediated gene transfer in conjunction with stereotactic surgery has previously demonstrated the proficiency of several nuclear calcium-regulated genes to protect in vivo against brain damage caused by toxic extrasynaptic NMDA receptor signaling following seizures or stroke. Here we used noninvasive nose-to-brain administration of Activin A and SerpinB2, two secreted nuclear calcium-regulated neuroprotectants, for post-injury treatment of brain damage following middle cerebral artery occlusion (MCAO) in C57BL/6N mice. The observed reduction of the infarct volume was comparable to the protection obtained by intracerebroventricular injection of recombinant Activin A or SerpinB2 or by stereotactic delivery 3 weeks prior to the injury of a recombinant adeno-associated virus containing an expression cassette for the potent neuroprotective transcription factor Npas4. These results establish post-injury, nose-to-brain delivery of Activin A and SerpinB2 as effective and possibly clinically applicable treatments of acute and chronic neurodegenerative conditions.

CRISPR/Cas9 nickase mediated targeting of urokinase receptor gene inhibits neuroblastoma cell proliferation

Neuroblastoma is a tumor arising from pluripotent sympathoadrenal precursor cells of neural cell origin. Neuroblastoma is one of the most aggressive childhood tumors with highly invasive and metastatic potential. The increased expression of urokinase and its receptor is often associated with a negative prognosis in neuroblastoma patients.

We have shown that targeting of the Plaur gene in mouse neuroblastoma Neuro 2A cells by CRISPR/Cas9n results in ~60% decrease in cell proliferation (p<0.05), reduction in the number of Ki-67 positive cells, caspase 3 activation and PARP-1 cleavage. Knockout of uPAR leads to downregulation of mRNA encoding full-length TrkC receptor, which is involved in p38^MAPK and Akt signalling pathways. This finding provides a rationale to study a role of uPAR in neuroblastoma progression, since uPAR could be considered a potential therapeutic target in neuroblastoma treatment.

Prognostic and Predictive value of the Urokinase-Type Plasminogen Activator (uPA) and Its Inhibitors PAI-1 and PAI-2 in Operable Breast Cancer

The present study on the prognostic and predictive value of serine proteases was conducted in 460 early breast cancer patients mostly treated with some kind of adjuvant systemic therapy: 156 received chemotherapy, 141 hormone therapy and 111 a combination of both. Already in univariate analysis PAI-1 was the only proteolytic factor with a significant impact on DFS, which was retained in multivariate analysis (p=0.020); PAI-2 showed borderline significance in univariate analysis (p=0.0503) and uPA did not present as a significant prognostic factor for DFS in our patient series. In a separate univariate analysis of DFS on patient subgroups defined by adjuvant systemic therapy, a higher risk of relapse associated with higher uPA and PAI-1 levels was found in the subgroup of patients who did not receive any treatment; this difference did not reach the level of significance, probably due to the small number (n=52) of patients in this group (HR 1.37; p=0.71 and HR 2.14; p=0.321, respectively). A higher risk of relapse was also found in the subgroup of patients treated with adjuvant chemotherapy (HR 1.44; p=0.381 and HR 2.48; p=0.003, respectively). In contrast, the bad prognostic impact of high uPA and PAI-1 levels was lost in the subgroup of patients treated with adjuvant hormone therapy (HR 0.79; p=0.693 and HR 0.26; p=0.204, respectively). The same observations were made for the uPA/PAI-1 combination. Our study confirmed the prognostic value of serine proteases in early breast cancer. In addition, it pointed to a possible predictive value of these tumor markers for response to adjuvant hormone therapy with tamoxifen, which should be confirmed in further studies.

Plasminogen activator inhibitor type 2: still an enigmatic serpin but a model for gene regulation

Plasminogen activator inhibitor type-2 (PAI-2; SERPINB2) is an atypical member of the Ov-serpin family of serine protease inhibitors. While it is an undisputed inhibitor of urokinase and tissue-type plasminogen activator in the extracellular space and on the cell surface, the weight of circumstantial evidence suggests that PAI-2 also fulfills an intracellular role which is independent of plasminogen activator inhibition and indeed may not even involve protease inhibition at all. More and more data continue to implicate a role for PAI-2 in many settings, the most recent associating it as a modulator of the innate immune response. Further to the debates concerning its physiological role, there are few genes, if any, that display the regulation profile of the PAI-2 gene: PAI-2 protein and mRNA levels can be induced in the order of, not hundred-, but thousand-folds in a process that is controlled at many levels including gene transcription and mRNA stability while an epigenetic component is also likely. The ability of some cells, including monocytes, fibroblasts, and neurons to have the capacity to increase PAI-2 synthesis to such high levels is intriguing enough. So why do these cells have the capacity to synthesize so much of this protein? While tantalizing clues continue to be revealed to the field, an understanding of how this gene is regulated so profoundly has provided insights into the broader mechanics of gene expression and regulation.

High levels of uPA and PAI-1 predict a good response to anthracyclines

Urokinase-type plasminogen activator (uPA) and its main inhibitor (PAI-1) were shown with level 1 evidence to be prognostic factors for primary breast cancer. Our preliminary retrospective study on a cohort of 1,220 consecutive patients hinted that uPA and PAI-1 could also serve as predictive factors for systemic therapy, namely that patients with high levels of the two markers benefit much more from anthracycline-based chemotherapy than patients with low levels of the two markers. The latter could equally well be treated with less toxic CMF-based chemotherapy (cyclophosphamide, methotrexate, and fluorouracil). The retrospective study, however, suffered from severely uneven patient and tumor characteristics as the patients were treated per institutional guidelines valid at the time and were not randomized between the anthracycline and CMF arms. In the present paper, we attempted to remedy this shortcoming and recheck our previous observations on more balanced data. To this end we employed a custom-made computer algorithm that selected 180 patients out of a total of 1,220 patients such that we obtained very well balanced anthracycline and CMF arms according to patient and tumor characteristics. Moreover, the low and high uPA/PAI-1 subgroups within both arms were also completely balanced. The algorithm in a way created a similar setting to that of a randomized study at the expense of greatly reducing the number of patients included into the study. In this setting, we observed the 3-year disease-free survival (DFS) in all four subgroups (according to treatment and levels of markers: both uPA and PAI-1 low versus one or both high). We report that the 3-year DFS in the CMF arm differed significantly: 87.1% for patients with low levels of markers versus 77.0% for patients with high levels of markers (P = 0.044, HR = 2.81, 95% CI = 0.98-8.04). On the other hand, the 3-year DFS in the anthracycline arm did not differ much between the two marker level subgroups: 85.2% for patients with low levels of markers versus 81.8% for patients with high levels of markers. Our observation points out that worse prognosis correlated to high uPA and PAI-1 levels can be reversed by treatment efficacy achieved through anthracycline-based chemotherapy. Based on this observation, we hypothesize that uPA/PAI-1 combination could be predictive for response to systemic therapy.

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.

Cancer biomarkers: knowing the present and predicting the future

In recent years the discovery of cancer biomarkers has become a major focus of cancer research. The widespread use of prostate-specific antigen in prostate cancer screening has motivated researchers to identify suitable markers for screening different types of cancer. Biomarkers are also useful for diagnosis, monitoring disease progression, predicting disease recurrence and therapeutic treatment efficacy. With the advent of new and improved genomic and proteomic technologies such as DNA and tissue microarray, two-dimensional gel eletrophoresis, mass spectrometry and protein assays coupled with advanced bioinformatic tools, it is possible to develop biomarkers that are able to reliably and accurately predict outcomes during cancer management and treatment. In years to come, a serum or urine test for every phase of cancer may drive clinical decision making, supplementing or replacing currently existing invasive techniques.

The undecided serpin

Plasminogen activator inhibitor type-2 (PAI-2) is a nonconventional serine protease inhibitor (serpin) with unique and tantalizing properties that is generally considered to be an authentic and physiological inhibitor of urokinase. However, the fact that only a small percentage of PAI-2 is secreted has been a long-standing argument for alternative roles for this serpin. Indeed, PAI-2 has been shown to have a number of intracellular roles: it can alter gene expression, influence the rate of cell proliferation and differentiation, and inhibit apoptosis in a manner independent of urokinase inhibition. Despite these recent advances in defining the intracellular function of PAI-2, it still remains one of the most mysterious and enigmatic members of the serpin superfamily.

Role of urokinase plasminogen activator and its receptor in metastasis and invasion of neuroblastoma

BACKGROUND/PURPOSE

Urokinase plasminogen activator (uPA) is a serine proteinase that has been suggested to play an important role in tumor invasion and metastasis. It binds to a specific membrane receptor, uPA receptor (uPAR), and activates plasminogen to form plasmin, which participates in tissue degradation and proteolysis. Binding of uPA to its receptor accelerates the activation of uPA from pro-uPA, enhancing the activity of the uPA/uPAR cascade. Because of the high metastatic and invasive potential of neuroblastoma (NB) cells, the authors have analyzed in the current study, the concomitant of uPA and its receptor in NB.

METHODS

The expression and distribution of uPA and uPAR were analyzed by immunostaining in 52 neuroblastoma tissues; at the same time we use the reverse transcriptase polymerase chain reaction (RT-PCR) for neuroendocrine protein gene products 9.5 (PGP 9.5) mRNA to detect small numbers of NB cells in the peripheral blood and bone marrow (BM) and study the relationship uPA and uPAR to the ability of invasion and metastasis of NB cells. To identify risk factors for disease progression, the authors performed a retrospective analysis of clinical (age, sex, and risk group) and tumor biologic markers (histology, MYCN, DNA ploidy, chromosome 1 p, PGP9.5, uPA, uPAR, and combined uPA and uPAR) in all patients. Survival curves were estimated using the Kaplan-Meier method. Univariate analysis was performed with the log-rank test. Multivariate analysis was performed using the Cox proportional hazards regression model.

RESULTS

The results of immunohistochemistry showed that uPA and uPAR were localized mainly in the membrane and cytoplasm of tumor cells. The positive rate of uPA in the high-risk group (23 of 25, 92.0%) was remarkably higher than that in intermediate-risk group (8 of 17, 47.1%) and low-risk group (3 of 10, 30.0%), in UH (26 of 29, 89.7%) was higher than in FH (8 of 23, 34.8%), respectively, and statistical significance was remarkable both P < .01). Similar results were obtained for uPAR. The positive rate of uPAR in the high-risk group (22 of 25, 88.0%) was substantially higher compared with that in intermediate-risk group (6 of 17, 35.3%) and low-risk group (2 of 10, 20.0%; P < .01). The positive rate of uPAR in UH (24 of 29, 82.8%) was higher compared with that in FH (6 of 23, 26.1%), and statistical significance was remarkable (P < .01). PGP9.5 mRNA in peripheral blood and BM was detected in 24 of 52 (45.2%) patients. The positive rate of PGP 9.5 mRNA in peripheral blood and BM in the cases positive for uPA (22 of 34, 64.7%) was markedly higher than that in the cases negative for uPA (11.1%, 2 of 18), and statistical significance was remarkable (P < .01). There was significant difference in the positive rate of PGP9.5 mRNA between the group positive for uPAR (66.7%, 20 of 30) and the group negative for uPAR (18.2%, 4 of 22), and a larger difference was found between the group positive for both uPA and uPAR (73.1%, 19 of 26) and the group negative for uPA or uPAR (19.2%, 5 of 26). The overall survival (OS) and event-free survival (EFS) rates at 5 years for all patients were, respectively, 70% +/- 3% and 63% +/- 3% with a median follow-up of 65 months (range 13 to 20). Among all the biologic and clinical features analyzed, multivariate analysis using Cox proportional hazards regression showed that age, MYCN, and combined uPA and uPAR remained significant predictors for both OS and EFS (P < .01, respectively). Both EFS rate and OS rate were significantly better for patients who positively expressed uPA and uPAR than those who negatively expressed uPA or uPAR.

CONCLUSIONS

This study showed that uPA and uPAR were overexpressed in high-risk and UH tumor of NB, and that overexpression of both factors was associated with the ability of invasion, metastasis, and prognosis of NB. The presence of high levels of combined uPA and uPAR may be a new prognostic marker that would allow us to identify patients with poorer prognosis who might benefit from more aggressive surgical and adjuvant treatment.

Plasminogen activator inhibitor-2 (PAI-2) in eosinophilic leukocytes

Plasminogen activator inhibitor-2 (PAI-2) as a potential eosinophil protein was inferred from our gene microarray study of mouse eosinophilopoiesis. Here, we detect 47 kDa intracellular and approximately 60 kDa secretory forms of PAI-2 in purified human eosinophil extracts. PAI-2 is present at variable concentrations in eosinophil lysates, ranging from 30 to 444 ng/10(6) cells, with a mean of 182 ng/10(6) cells from 10 normal donors, which is the highest per-cell concentration among all leukocyte subtypes evaluated. Enzymatic assay confirmed that eosinophil-derived PAI-2 is biologically active and inhibits activation of its preferred substrate, urokinase. Immunohistochemical and immunogold staining demonstrated PAI-2 localization in eosinophil-specific granules. Immunoreactive PAI-2 was detected in extracellular deposits in and around the eosinophil-enriched granuloma tissue encapsulating the parasitic egg in livers of wild-type mice infected with the helminthic parasite Schistosoma mansoni. Among the possibilities, we consider a role for eosinophil-derived PAI-2 in inflammation and remodeling associated with parasitic infection as well as allergic airways disease, respiratory virus infection, and host responses to tumors and metastasis in vivo.

Recent progress in predictive biomarkers for metastatic recurrence of human hepatocellular carcinoma: a review of the literature

Molecular markers (biomarkers) for hepatocellular carcinoma (HCC) metastasis and recurrence could provide additional information to that gained from traditional histopathological features. A large number of biomarkers have been shown to have potential predictive significance. One important aspect of this is to detect the transcripts of tumor-associated antigens (such as AFP, MAGEs, and CK19), which are proposed as predictive markers of HCC cells disseminated into the circulation and for metastatic recurrence. Another important aspect is to analyze the molecular markers for cellular malignancy phenotype, including DNA ploidy, cellular proliferation index, cell cycle regulators, oncogenes, and tumor suppressors (especially p53 gene), as well as telomerase activity. Molecular factors involved in the process of HCC invasion and metastasis, including adhesion molecules (E-cadherin, catenins, ICAM-1, laminin-5, CD44 variants, osteopontin), proteinases responsible for the degradation of extracellular matrix (MMPs, uPA system), as well as angiogenesis regulators (such as VEGF, intratumor MVD), have also been shown to be potential predictors for HCC metastatic recurrence and clinical outcomes. One important new trend is to widely delineate biomarkers with genomic and proteomic expression with reference to predicting metastatic recurrence, molecular diagnosis, and classification, which has been drawing more attention recently. Body fluid (particularly blood and urine) testing for biomarkers is easily accessible and more useful in clinical patients. The prognostic significance of circulating DNA in plasma or serum and its genetic alterations is another important direction. More attention should be paid to these areas in the future. As understanding of tumor biology deepens, more and more new biomarkers with high sensitivity and specificity for HCC metastatic recurrence could be found and routinely used in clinical assays. However, the combination of the pathological features and some of the biomarkers mentioned above seems to be more practical up to now.

Overexpression of a set of genes, including WISP-1, common to pulmonary metastases of both mouse D122 Lewis lung carcinoma and B16-F10.9 melanoma cell lines

Despite advances in the management of solid tumours, the development of metastases continues to be the most significant problem and cause of death for cancer patients. To define genetic determinants of pulmonary metastases, we have applied oligonucleotide microarrays to established murine models of highly metastatic D122 Lewis lung carcinoma and B16-F10.9 melanoma cell lines. These models are characterised by primary subcutaneous growth in C57BL/6J mice, a period of minimal residual disease and spontaneous pulmonary metastases. Microarray analysis defined seven genes, namely - arginase, brain natriuretic peptide (BNP), interleukin-1 alpha (IL-1 alpha), plasminogen activator inhibitor-2 (PAI-2), surfactant protein C (SP-C), uteroglobin (UG) and wnt-1-induced secreted protein-1 (WISP-1), which were consistently elevated in pulmonary metastases compared to the primary tumour of both D122 and B16-F10.9 models. Previous studies demonstrated that two of these seven genes, IL-1 alpha and PAI-2, are involved in the metastatic process. The results obtained by the microarrays were confirmed by real-time quantitative PCR, for three chosen genes - PAI-2, WISP-1 and UG. Our approach aimed to identify genes essential for the metastatic process in general and for pulmonary metastases specifically. Further research should address the precise role of these genes in the metastasising process to the lungs and test if they could be used as targets for future therapies.