Urinary angiostatin levels are elevated in patients with epithelial ovarian cancer

Platelet-Cancer Interplay: Molecular Mechanisms and New Therapeutic Avenues

Although platelets are critically involved in thrombosis and hemostasis, experimental and clinical evidence indicate that platelets promote tumor progression and metastasis through a wide range of physical and functional interactions between platelets and cancer cells. Thrombotic and thromboembolic events are frequent complications in patients with solid tumors. Hence, cancer modulates platelet function by directly inducing platelet-tumor aggregates and triggering platelet granule release and altering platelet turnover. Also, platelets enhance tumor cell dissemination by activating endothelial cell function and recruiting immune cells to primary and metastatic tumor sites. In this review, we summarize current knowledge on the complex interactions between platelets and tumor cells and the host microenvironment. We also critically discuss the potential of anti-platelet agents for cancer prevention and treatment.

The "Janus Face" of Platelets in Cancer

Besides their vital role in hemostasis and thrombosis, platelets are also recognized to be involved in cancer, where they play an unexpected central role: They actively influence cancer cell behavior, but, on the other hand, platelet physiology and phenotype are impacted by tumor cells. The existence of this platelet-cancer loop is supported by a large number of experimental and human studies reporting an association between alterations in platelet number and functions and cancer, often in a way dependent on patient, cancer type and treatment. Herein, we shall report on an update on platelet-cancer relationships, with a particular emphasis on how platelets might exert either a protective or a deleterious action in all steps of cancer progression. To this end, we will describe the impact of (i) platelet count, (ii) bioactive molecules secreted upon platelet activation, and (iii) microvesicle-derived miRNAs on cancer behavior. Potential explanations of conflicting results are also reported: Both intrinsic (heterogeneity in platelet-derived bioactive molecules with either inhibitory or stimulatory properties; features of cancer cell types, such as aggressiveness and/or tumour stage) and extrinsic (heterogeneous characteristics of cancer patients, study design and sample preparation) factors, together with other confounding elements, contribute to “the Janus face” of platelets in cancer. Given the difficulty to establish the univocal role of platelets in a tumor, a better understanding of their exact contribution is warranted, in order to identify an efficient therapeutic strategy for cancer management, as well as for better prevention, screening and risk assessment protocols.

Ovarian Cancer Biomarkers: Moving Forward in Early Detection

Ovarian cancer is a silent cancer which rate survival mainly relays in early stage detection. The discovery of reliable ovarian cancer biomarkers plays a crucial role in the disease management and strongly impact in patient's prognosis and survival. Although having many limitations CA125 is a classical ovarian cancer biomarker, but current research using proteomic or metabolomic methodologies struggles to find alternative biomarkers, using non-invasive our relatively non-invasive sources such as urine, serum, plasma, tissue, ascites or exosomes. Metabolism and metabolites are key players in cancer biology and its importance in biomarkers discovery cannot be neglected. In this chapter we overview the state of art and the challenges facing the use and discovery of biomarkers and focus on ovarian cancer early detection.

Urinary VEGF and PGE2 levels and the association with arsenical metabolites in copper-smelting workers

OBJECTIVES

To examine vascular endothelial growth factor (VEGF) and PGE2 levels in urine from the copper smelting workers exposed to arsenic and analyse the relationships between urinary VEGF or PGE2 level and arsenical metabolites.

METHODS

The study was conducted in a group of 106 copper-smelting male workers. Information about each subject was obtained by questionnaire, inorganic As (iAs), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), VEGF and prostaglandin E2 (PGE2) in urine were determined. Standing height, body weight, and blood pressure were measured.

RESULTS

According to the urine arsenic levels, participants were separated into three groups: Group 1: urine total arsenic <35 mg/L, Group 2: 35-100 mg/L, and Group 3: >100 mg/L. The median levels of urinary VEGF and PGE2 in Groups 1, 2 and 3 were 10.57 and 1032.0 pg/mL, 24.39 and 1060.9 pg/mL, and 49.0 and 1330.4 pg/mL, respectively. Urinary VEGF levels were positive associated with arsenical metabolites (iAs, MMA, DMA and TAs). Additionally, urinary VEGF and PGE2 levels were all correlated positively with the urinary MMA% (r=0.221, p=0.026 and r=0.206, p=0.037). While urinary VEGF was negatively with DMA% and secondary methylation index (r=-0.242, p=0.014 and r=-0.214, p=0.030, respectively).

CONCLUSIONS

Urinary VEGF and PGE2 levels increased in arsenic exposure copper smelting workers, and urinary VEGF levels are well associated with the urinary arsenicals. This finding may provide useful information for developing measurement, prevention and treatment of damage induced by arsenic in the future.

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.

Serum levels of angiogenic and anti-angiogenic factors: their prognostic relevance in locally advanced hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a prototype tumor wherein angiogenesis plays a vital role in its progression. The role of VEGF, a major angiogenic factor in HCC is known; however, the role of anti-angiogenic factors simultaneously with the angiogenic factors has not been studied before. Hence, in this study, the serum levels of major angiogenic [Vascular Endothelial Growth Factor (VEGF), angiopoietin-2 (Ang-2)] and anti-angiogenic (endostatin, angiostatin) factors were analyzed and correlated with clinico-radiological features and with outcome. A total of 150 patients (50 HCC, 50 cirrhosis and 50 chronic hepatitis) and 50 healthy controls were enrolled in this study. Serum levels of VEGF, Ang-2, endostatin, and angiostatin were estimated by enzyme-linked immunosorbent assay. HCC shows significantly elevated serum levels of angiogenic factors VEGF and Ang-2 and of anti-angiogenic factors endostatin and angiostatin. ROC curve analysis for serum VEGF yielded an optimal cut-off value of 225.14 pg/ml, with a sensitivity of 78 % and specificity of 84.7 % for a diagnosis of HCC and its distinction from other group. Using this value, the univariate and multivariate analysis revealed significantly poor outcome in patients with higher levels of serum VEGF (p = 0.009). Combinatorial analysis revealed that patients with higher levels of both angiogenic and anti-angiogenic factors showed poor outcome. Serum VEGF correlates with poor survival of HCC patients and, therefore, serves as a non-invasive biomarker of poor prognosis. Moreover, elevated levels of anti-angiogenic factors occur endogenously in HCC patients.

Circulating angiostatin, bFGF, and Tie2/TEK levels and their prognostic impact in bladder cancer

OBJECTIVE

To assess the role and prognostic significance of angiostatin, basic fibroblast growth factor (bFGF), and tyrosine endothelial kinase (TEK/Tie2) in transitional cell bladder carcinoma.

MATERIALS AND METHODS

Angiostatin, bFGF, and TEK serum concentrations were measured in 82 bladder cancer patients and 20 age-matched healthy controls using enzyme-linked immunosorbent assay. Results were compared with clinicopathologic and follow-up data with the Mann-Whitney U test and Kaplan-Meier, univariate and multivariate Cox regression analyses.

RESULTS

We found significantly decreased angiostatin and TEK serum levels and mildly elevated bFGF concentrations in samples of bladder cancer patients compared with controls (P < .001, P < .001, and P = .083, respectively). Furthermore, high TEK serum levels were correlated with poor disease-specific and metastasis-free survival in muscle-invasive bladder cancer (P = .013, P = .018), whereas angiostatin and bFGF concentrations did not show any correlation with patients' prognosis. Multivariate analysis revealed high TEK levels (<1.60 ng/mL) as borderline significant independent risk-factor of disease-specific survival (HR 1.83, 95% CI 0.97-3.44, P = .061) and metastasis-free survival (HR 2.65, 95% CI 0.93-7.55, P = .069).

CONCLUSION

The characteristic differences in the circulating levels of angiostatin, TEK, and bFGF between patients and controls, suggest the presence of a tumor-induced proangiogenic milieu in bladder cancer. Serum TEK levels may contribute to a more reliable preoperative risk stratification in muscle-invasive bladder cancer and therefore may help to optimize therapeutic decisions.

-The advancement of biomarker-based diagnostic tools for ovarian, breast, and pancreatic cancer through the use of urine as an analytical biofluid

Despite considerable advancements, the development of effective cancer screening tools based on serum biomarker measurements has thus far failed to achieve a meaningful clinical impact. The incremental progress observed over the course of serum biomarker development suggests that further refinements based on novel approaches may yet result in a breakthrough. The use of urine as an analytical biofluid for biomarker development may represent such an approach. The unique characteristics of urine including a high level of stability, ease of sampling, and an inactive and low-complexity testing matrix offer several potential advantages over the use of serum. A number of recent reports have demonstrated the utility of urine in the identification of novel cancer biomarkers and also the improved performance of biomarkers previously evaluated in serum. In this review, advancements related to the use of urine biomarkers within the settings of ovarian, breast, and pancreatic cancer are presented and discussed. Findings regarding the identification of specific urine biomarkers for each disease are highlighted along with comparative analyses of urine and serum biomarkers as diagnostic tools.