The complex between urokinase-type plasminogen activator (uPA) and its type-1 inhibitor (PAI-I) independently predicts response to first-line endocrine therapy in advanced breast cancer

uPA-PAI-1 heteromerization promotes breast cancer progression by attracting tumorigenic neutrophils

High intratumoral levels of urokinase-type plasminogen activator (uPA)-plasminogen activator inhibitor-1 (PAI-1) heteromers predict impaired survival and treatment response in early breast cancer. The pathogenetic role of this protein complex remains obscure. Here, we demonstrate that heteromerization of uPA and PAI-1 multiplies the potential of the single proteins to attract pro-tumorigenic neutrophils. To this end, tumor-released uPA-PAI-1 utilizes very low-density lipoprotein receptor and mitogen-activated protein kinases to initiate a pro-inflammatory program in perivascular macrophages. This enforces neutrophil trafficking to cancerous lesions and skews these immune cells toward a pro-tumorigenic phenotype, thus supporting tumor growth and metastasis. Blockade of uPA-PAI-1 heteromerization by a novel small-molecule inhibitor interfered with these events and effectively prevented tumor progression. Our findings identify a therapeutically targetable, hitherto unknown interplay between hemostasis and innate immunity that drives breast cancer progression. As a personalized immunotherapeutic strategy, blockade of uPA-PAI-1 heteromerization might be particularly beneficial for patients with highly aggressive uPA-PAI-1high tumors.

Prognostic impact of the inclusion of uPA/PAI-1 for adjuvant treatment decision-making in ER+/Her2- pN0 early breast cancers

PURPOSE

Intermediate-risk early breast cancer (EBC) is a heterogeneous group in which adjuvant chemotherapy decision proves to be difficult. Clinical and pathological criteria are sometimes insufficient to determine the best therapeutic options, and validated biomarkers such as uPA/PAI-1, are needed to contribute to the decision-making. The objective of this study was to evaluate the clinical outcome of an unselected ER+/HER2- pN0 EBC cohort of patients in whom the routine clinical decision process included a prospective uPA/PAI-1 determination.

METHOD

This monocentric retrospective study included 520 patients who underwent curative surgery in our institute between 2006 and 2011. Adjuvant therapeutic strategy was decided based on clinical-pathological data, altogether with a routine prospective determination of uPA/PAI-1 tumor levels using fresh, extemporaneously sampled tissue. We evaluated the correlation between uPA/PAI-1 levels, clinical-pathological variables, and the patient's outcome (relapse-free survival, RFS, and overall survival, OS).

RESULT

Median follow-up was 5.4 years. The 5- and 10-year RFS rates were ,respectively, 95 and 89%, and the five-year OS rate was 96.3%. Forty percent of tumors had low uPA/PAI-1 levels. Seventy-five percent of patients with low uPA/PAI-1 levels did not receive chemotherapy, when 25% did. Sixty percent of patients with high uPA and/or PAI-1 levels received chemotherapy, while 40% did not. No statistical significant correlation was found between the uPA/PAI-1 levels and RFS or OS.

CONCLUSION

The personalization of the patients' treatment using uPA/PAI-1 tumor levels allows the reversion of the well-known poor prognostic impact of high uPA/PAI-1 levels and strongly supports the use of this biomarker in clinical practice.

Plasminogen activators are involved in angiostatin generation in vivo in benign and malignant ovarian tumor cyst fluids

In many tumor types, angiogenesis is the net result of pro- and anti-angiogenic mediators and correlated with metabolic activity, growth, and degree of malignancy. One of the first discovered anti-angiogenic compounds is angiostatin, a proteolytic fragment of plasminogen. The requirements for in vivo angiostatin generation have not yet been determined. We investigated the levels of plasminogen and angiostatin by western blotting and of components of the plasminogen activator complex by ELISA in cyst fluid derived from benign and malignant ovarian tumors. Fluid samples from functional ovarian follicles, dermoid cysts and endometriotic lesions were evaluated separately. When no or minimal amounts of plasminogen were present in the cyst fluids, angiostatin was generally absent as well, irrespective of plasminogen activator concentrations. When plasminogen was present, the degree of conversion of plasminogen to angiostatin was significantly correlated with the level of uPA, and, to a lesser extent, to the tPA level. However, angiostatin was also found in a number of cyst fluid samples with minimal or no plasminogen activators, suggesting the involvement of other angiostatin generating proteases in these samples. Conversely, no angiostatin was observed in a number of cyst fluid samples containing both plasminogen and plasminogen activators. The presence of an inhibitor of the enzymatic activity of uPA and/or tPA, like PAI-1, may explain this finding. Our data show that plasminogen activators are clearly involved in in vivo angiostatin formation in ovarian cysts. Most likely, however, other proteases, as well as inhibitors of plasminogen activators, are involved as well.

Tumour-microenvironment interactions: role of tumour stroma and proteins produced by cancer-associated fibroblasts in chemotherapy response

BACKGROUND

Cytotoxic chemotherapy improves survival for some, but not all, cancer patients. Non-responders may experience unnecessary toxicity and cancer progression, thus creating an urgent need for biomarkers that can predict the response to chemotherapy. So far, the search for such biomarkers has primarily been focused on the cancer cells and less on their surrounding stroma. This stroma is known to act as a key regulator of tumour progression and, in addition, has been associated with drug delivery and drug efficacy. Fibroblasts represent the major cell type in cancer-associated stroma and they secrete extracellular matrix proteins as well as growth factors. This Medline-based literature review summarises the results from studies on epithelial cancers and aimed at investigating relationships between the quantity and quality of the intra-tumoral stroma, the cancer-associated fibroblasts, the proteins they produce and the concomitant response to chemotherapy. Biomarkers were selected for review that are known to affect cancer-related characteristics and patient prognosis.

RESULTS

The current literature supports the hypothesis that biomarkers derived from the tumour stroma may be useful to predict response to chemotherapy. This notion appears to be related to the overall quantity and cellularity of the intra-tumoural stroma and the predominant constituents of the extracellular matrix.

CONCLUSION

Increasing evidence is emerging showing that tumour-stroma interactions may not only affect tumour progression and patient prognosis, but also the response to chemotherapy. The tumour stroma-derived biomarkers that appear to be most appropriate to determine the patient's response to chemotherapy vary by tumour origin and the availability of pre-treatment tissue. For patients scheduled for adjuvant chemotherapy, the most promising biomarker appears to be the PLAU: SERPINE complex, whereas for patients scheduled for neo-adjuvant chemotherapy the tumour stroma quantity appears to be most relevant.

Components of the plasminogen activator system and their complexes in renal cell and bladder cancer: comparison between normal and matched cancerous tissues

OBJECTIVE

To analyse and compare the concentration of plasminogen activator (PA), urokinase-type PA (uPA), tissue-type PA (tPA), PA inhibitor (PAI)-1 and PAI-2, and the complexes uPA-PAI-1 and tPA-PAI-1 and calculated uPA and tPA uncomplexed with PAI-1 ('free') in urothelial cell carcinoma and matched benign urothelium, and in renal cell carcinoma (RCC) and matched benign renal tissue.

PATIENTS AND METHODS

Tissue samples were obtained during cystectomy (33 patients) and nephrectomy (55), and specific enzyme-linked immunosorbent assays were used to assess the PA components in extracts of these tissues.

RESULTS

Tissue levels of uPA-PAI-1 and tPA-PAI-1, but also PAI-1 itself, were greater in tumorous bladder and kidney tissue than in matched normal tissue (by 1.5-7.8 times). Free tPA was clearly lower in tumour tissue (by 0-0.12-fold). In bladder cancer, but not in RCC, levels of uPA (15.8-fold) and free uPA (16.4-fold) were greater in tumour tissue. Free uPA levels were less in RCC (0.41-fold). For both normal bladder and kidney tissue, there was no clear correlation between uPA-PAI-1 complex and either component. However, the formation of tPA-PAI-1 complexes in normal bladder and kidney tissue was primarily determined by PAI-1. Interestingly, in tumour tissues there was a strong, significant correlation between complex levels and both components.

CONCLUSION

RCC and bladder cancer show distinct profiles of components of the PA system. This study provides a basis for further studies into both the (patho)physiological role of the PA system in these tumours, and into a possible relation with tumour progression and prognosis, and as target for therapy.

Urokinase-type plasminogen activator and plasminogen activator inhibitor type-1 mRNA assessment in breast cancer by means of NASBA: correlation with protein expression

Urokinase plasminogen activator (uPA) and its main inhibitor, plasminogen activator inhibitor type-1 (PAI-1) determined in tumor tissue by means of enzyme-linked immunosorbent assay (ELISA) can discriminate patients with primary breast cancer at high risk vs low risk for recurrence. The aim of this study was to analyze uPA and PAI-1 messenger RNA (mRNA) expression by means of quantitative nucleic acid sequence-based amplification (NASBA) on 77 primary breast tumor samples and to correlate this expression with the uPA and PAI-1 protein content. We observed that the 2 markers were significantly overexpressed (uPA, P < .0001; PAI-1, P = .0042) in mRNA in the ELISA+ group. The receiver operating characteristic (ROC) curves demonstrated high concordance between NASBA and ELISA (area under the ROC curve of 0.84 and 0.70 for uPA and PAI-1, respectively) and showed that uPA and PAI-1 status could be predicted by using the molecular assay with sensitivity and specificity values of 80.8% and 82.4% and sensitivity and specificity values of 66.7% and 74.0%, respectively.

Co-expression of steroid receptors (estrogen receptor alpha and/or progesterone receptors) and Her-2/neu: Clinical implications

The response of breast cancer patients to endocrine therapy is guided by the expression of two steroid hormone receptors (HR): estrogen receptor alpha (ERalpha) and/or progesterone receptors (PR). In most laboratories the expression of these predictive markers is studied by immunohistochemistry (IHC) in the breast cancer biopsy samples. Another molecular marker that is being increasingly examined in breast cancer is the oncoprotein Her-2/neu, whose expression/amplification predicts the response to anti-Her-2/neu immunotherapy. The co-expression of HR with that of Her-2/neu is infrequent (most reports agree on this), however, there are some conflicting reports about the clinical implications in term of response to endocrine therapy in the patients that co-express HR and Her-2/neu. We have examined these molecular markers for a number of years in our tumor bank, in this dissertation we will present the method and cut-off to study these markers, the correlations between their expression, and the follow-up of the patients that received tamoxifen-based endocrine therapy, alone or following chemotherapy. We confirmed that the co-expression of HR with Her-2/neu is infrequent, and that these patients presented both a shorter disease free survival and overall survival. Our results will be compared with others related recently published. For example, the aromatase inhibitor anastrozole appears to be an effective endocrine treatment in HR+ patients, irrespective of the Her-2/neu status. We will present data on the molecular mechanisms that could explain the relatively poor outcome of these patients. Heregulin has been found to be a potent inducer of heat shock factor 1 (HSF1) activity and of heat shock protein (Hsp) synthesis in breast cancer cells and HSF1 activation plays a role in the tumorigenic changes induced by heregulin, heregulin exerts its tumorigenic changes through the cell surface tyrosine kinase receptors c-erbB-3 and c-erbB-4 which are able to form dimers with the "ligandless" Her-2/neu. We found that HSF1 associates with metastasis associated protein 1 (MTA1) on the promoters of genes as well as other molecules involved in gene repression (HDAC1, HDAC2) in a manner that is enhanced by either heregulin exposure or heat shock. ERs, although promoting the growth of breast cancer cells are less associated with invasion/metastasis and ER-induced gene expression is involve in this effect. Heregulin can overcome the protective effects of ER and at least a component of this appears to be due to MTA1 repression of ERE dependent transcription, HSF1 and MTA1 cooperate in gene repression. The co-expression of HSF1 and MTA1 was confirmed by IHC in human breast cancer biopsy samples.

"Resurrection of clinical efficacy" after resistance to endocrine therapy in metastatic breast cancer

Background

In a significant proportion of metastatic breast cancer (MBC) patients whose tumour has progressed within 6 months of endocrine therapy (de novo resistance), it is generally believed that the chance of achieving clinical benefit (CB) with further endocrine therapy is minimal.

Methods

Data was retrieved from a prospectively updated database of metastatic breast cancer. Relevant data was exported to SPSS™ software for statistical analysis.

Results

In oestrogen receptor (ER) positive MBC patients with assessable disease, CB was achieved in 159 (71.3%) (1^st line) patients. When these patients were put on further endocrine therapy, the CB rates were 63.2% (on 2^nd line), 46.1% (on 3^rd line) and 20% (on 4^th line) with a median duration of response (DOR) in those with CB of 22, 12, 11 and 15 months respectively. The remaining 64(28.7%) patients had de novo resistance on 1^st line endocrine therapy. Seventeen of these patients were treated with further endocrine therapy. The CB rates were 29.4% (on 2^nd line) and 22.2% (on 3^rd line) with a median DOR in those with CB of 22.7 months and 14 months respectively.

Conclusion

The chance of further endocrine response continues to decrease with each line of therapy, yet CB is still seen with reasonable duration even with a 4^th line agent. In addition, further endocrine response, with long duration, can be seen in a significant proportion of patients who have developed de novo resistance to 1^st line endocrine therapy. The use of further endocrine therapy should not be excluded under these circumstances.