Thrombin induces tumor cell cycle activation and spontaneous growth by down-regulation of p27Kip1, in association with the up-regulation of Skp2 and MiR-222

Integrative analysis of HASMCs gene expression profile revealed the role of thrombin in the pathogenesis of atherosclerosis

We explored the effect of thrombin on human aortic smooth muscle cells (HASMCs) and further analyzed its role in the pathogenesis of atherosclerosis (AS). Thrombin-induced differentially expressed genes (DEGs) in HASMCs were identified by analyzing expression profiles from the GEO. Subsequently, enrichment analysis, GSEA, PPI network, and gene-microRNAs networks were interrogated to identify hub genes and associated pathways. Enrichment analysis results indicated that thrombin causes HASMCs to secrete various pro-inflammatory cytokines and chemokines, exacerbating local inflammatory response in AS. Moreover, we identified 9 HUB genes in the PPI network, which are closely related to the inflammatory response and the promotion of the cell cycle. Additionally, we found that thrombin inhibits lipid metabolism and autophagy of HASMCs, potentially contributing to smooth muscle-derived foam cell formation. Our study deepens a mechanistic understanding of the effect of thrombin on HASMCs and provides new insight into treating AS.

miRNAs and androgen deprivation therapy for prostate cancer

Androgen deprivation therapy (ADT) is mainly used for the treatment of advanced, metastatic or recurrent prostate cancer (PCa). However, patients progress to ADT resistance and castration-resistant prostate cancer (CRPC) with a poor prognosis. Reliable validated markers of ADT resistance with proven clinical utility are necessary for timely correction of the therapy as well as for improvement of patient quality of life. MiRNAs involved in the ADT response and CRPC development via multiple mechanisms may act as biomarkers for patient outcomes. Available data on miRNAs associated with the ADT response (resistance and sensitivity) are summarized and analyzed in the manuscript, including analyses using bioinformatics resources. Molecular targets of miRNAs, as well as reciprocal relations between miRNAs and their targets, were studied using different databases. Special attention was dedicated to the mechanisms of ADT resistance and CRPC development, including testosterone, PI3K-AKT, VEGF pathways and associated genes. Several different approaches can be used to search for miRNAs associated with the ADT response, each of which focuses on the associated set of miRNAs - potential markers of ADT. The intersection of these approaches and combined analysis allowed us to select the most promising miRNA markers of the ADT response. Meta-analysis of the current data indicated that the selected 5 miRNAs (miRNAs - 125b, miR-21, miR-23b, miR-27b and miR-221) and 14 genes are involved in the regulation of key processes of CRPC development and represent the most promising predictors of the ADT response, further demonstrating their potential in combination therapy for advanced PCa.

Changes in miR-222 expression, DNA repair capacity, and MDM2-p53 axis in association with low-dose benzene genotoxicity and hematotoxicity

Mechanisms for hematotoxicity and health effects from exposure to low doses of benzene (BZ) remain to be identified. To address the information gap, our investigation was focused onto using appropriate populations and cell cultures to investigate novel BZ-induced effects such as disruption of DNA repair capacity (DRC). From our study, abnormal miRNAs were identified and validated using lymphocytes from 56 BZ-poisoned workers and 53 controls. In addition, 173 current BZ-exposed workers and 58 controls were investigated for key miRNA expression using RT-PCR and for cellular DRC using a challenge assay. Subsequently, the observed activities in lymphocytes were verified using human HL-60 (p53 null) and TK6 (p53 wild-type) cells via 1,4-benzoquinone (1,4-BQ) treatment and miR-222 interferences. The targeting of MDM2 by miR-222 was validated using a luciferase reporter. Our results indicate induction of genotoxicity in lymphocytes from workers with low exposure doses to BZ. In addition, miR-222 expression was up-regulated among both BZ-poisoned and BZ-exposed workers together with inverse association with DRC. Our in vitro validation studies using both cell lines indicate that 1,4-BQ exposure increased expression of miR-222 and Comet tail length but decreased DRC. Loss of miR-222 reduced DNA damage, but induced S-phase arrest and apoptosis. However, silencing of MDM2 failed to activate p53 in TK6 cells. In conclusion, our in vivo observations were confirmed by in vitro studies showing that BZ/1,4-BQ exposures caused genotoxicity and high expression of miR-222 which obstructed expression of the MDM2-p53 axis that led to failed activation of p53, abnormal DRC and serious biological consequences.

Clinical Significance of Serum Antithrombin III Activity After Hepatectomy for Hepatocellular Carcinoma

Background

As antithrombin III (AT-III) is produced in the hepatocytes, its serum activity decreases at the time of liver failure, in addition to ischemia reperfusion injury, vascular endothelial dysfunction, and disseminated intravascular coagulation (DIC). Here, we examined whether the serum AT-III value after hepatectomy could be a prognostic factor for hepatocellular carcinoma (HCC).

Methods

Of 141 patients who underwent hepatectomy for HCC, data for 101 patients in whom serum AT-III activity was measured on the first postoperative day were extracted. Patients with serum AT-III activity > 50% and ≤ 50% were assigned to high value (72 cases) and low value (29 cases) groups, respectively. We examined the clinical and prognostic differences between these two groups.

Results

The average age of enrolled patients (83 men and 18 women) was 68.0 years. The 5-year overall survival rate was 88% and 60% in the high and low value groups, respectively (P < 0.01). Furthermore, the 2-year relapse-free survival rate was 71% and 54% in the high and low value groups, respectively (P = 0.03).

Conclusion

This is the first study to demonstrate that serum AT-III levels on the first postoperative day may serve as a prognostic factor in HCC patients.

Early Prediction Model of Gestational Hypertension by Multi-Biomarkers Before 20 Weeks Gestation

BACKGROUND

Gestational hypertension (GH), a hypertensive disorder of pregnancy (HDP), is a leading cause of maternal and fetal mortality due to the lack of clarity on its exact etiology and clinically feasible prediction models. This study was performed to discover novel biomarkers before 20 weeks gestation and thereby construct an early GH prediction model.

METHODS

This study was designed based on differentially expressed protein screening followed by clinical validation. In the screening phase, a nested case-controlled study was conducted by plasma proteomic analyses using label-free LC-MS/MS and plasma samples from seven pre-GH cases before 20-week gestation and seven age- and gestational week-matched controls. In the validation phase, 10 proteins with differential expression in the screening phase were validated by ELISA or electrochemiluminescence in an independent study consisting of 29 pre-GH cases before 20-week gestation and 29 matched controls.

RESULTS

In the screening phase, 149 proteins were found to be differentially expressed between the two groups and were predominantly involved in complement and coagulation cascades, platelet degranulation and positive regulation of cell motility. Further validation showed that serpin family C member 1 (SERPINC1), serpin family A member 5 (SERPINA5), complement factor H-related protein 5 (CFHR5), clusterin, cytokeratin 18 (CK18) and histidine-rich glycoprotein (HRG) levels were significantly higher in women who later developed GH compared to women with uncomplicated pregnancies (P<0.05). Binary logistic regression analysis was used to determine the combination efficacy of models for early prediction of GH. The model with a combination of SERPINC1, CK18 and HRG had a significantly better discriminatory power (AUC = 0.91, 95% CI 0.83-0.98) compared to the models with those proteins alone as independent predictors of GH.

CONCLUSION

Plasma levels of SERPINC1, SERPINA5, CFHR5, clusterin, CK18 and HRG are potential novel predictive biomarkers of GH, and a prediction model using a combination of SERPINC1, CK18 and HRG has good discriminatory performance for GH before 20 weeks gestation.

Skp2 modulates proliferation, senescence and tumorigenesis of glioma

Background

Gliomas represent the largest class of primary central nervous system neoplasms, many subtypes of which exhibit poor prognoses. Surgery followed by radiotherapy and chemotherapy has been used as a standard strategy but yielded unsatisfactory improvements in patient survival outcomes. The S-phase kinase protein 2 (Skp2), a critical component of the E3-ligase SCF complex, has been documented in tumorigenesis in various cancer types but its role in glioma has yet to be fully clarified. In this study, we investigated the function of Skp2 in the proliferation, stem cell maintenance, and drug sensitivity to temozolomide (TMZ) of glioma.

Methods

To investigate the role of Skp2 in the prognosis of patients with glioma, we first analyzed data in databases TCGA and GTEx. To further clarify the effect of Skp2 on glioma cell proliferation, we suppressed its level in glioblastoma (GBM) cell lines through knockdown and small molecule inhibitors (lovastatin and SZL-P1-41). We then detected cell growth, colony formation, sphere formation, drug sensitivity, and in vivo tumor formation in xenograft mice model.

Results

Skp2 mRNA level was higher in both low-grade glioma and GBM than normal brain tissues. The knockdown of Skp2 increased cell sensitivity to TMZ, decreased cell proliferation and tumorigenesis. In addition, Skp2 level was found increased upon stem cells enriching, while the knockdown of Skp2 led to reduced sphere numbers. Downregulation of Skp2 also induced senescence. Repurposing of lovastatin and novel compound SZL-P1-41 suppressed Skp2 effectively, and enhanced glioma cell sensitivity to TMZ in vitro and in vivo.

Conclusion

Our data demonstrated that Skp2 modulated glioma cell proliferation in vitro and in vivo, stem cell maintenance, and cell sensitivity to TMZ, which indicated that Skp2 could be a potential target for long-term treatment.

Targeting hemostasis-related moieties for tumor treatment

Under normal conditions, the hemostatic system, that includes the involvement of the coagulation response and platelets, is anatomically and functionally inseparable from the vasculature. However, the hemostatic response always occurs in a wide range of tumors because of the high expression of coagulation initiator tissue factor (TF) in many tumor tissues, and due to the leakage of coagulation factors and platelets from the circulation system into the tumor interstitium through abnormal tumor vessels. Therefore, in addition to TF, these coagulation factors, platelets, the central moiety thrombin, the final product fibrin, and fibronectin, which is capable of stabilizing coagulation clots, are also abundant in tumors. These hemostasis-related moieties (HRMs), including TF, thrombin, fibrin, fibronectin, and platelets, are also closely associated with tumor progression, e.g., primary tumor growth and distal metastasis. The hemostatic response only occurs under pathological conditions, such as tumors, thrombosis, and atherosclerosis other than in normal tissues. The HRMs within tumors are also highly specific, establishing functional and therapeutic targets for tumor treatment. Therefore, strategies including active targeting to these moieties, modulation of HRMs deposited in the tumor microenvironment to improve tumor drug delivery, activation of prodrug by the coagulation complex formed during coagulation response, and direct inhibition of the tumor-promoting activity of HRMs could be designed for tumor therapy. In this review, we summarize various strategies that target HRMs for tumor treatment.

Protease-activated receptor-1 impedes prostate and intestinal tumor progression in mice

Essentials Protease activated receptor-1 (PAR-1) has been proposed to drive cancer progression. Surprisingly, PAR-1 deletion accelerated tumor progression in two distinct experimental settings. PAR-1 deletion was shown to limit the apoptosis of transformed epithelial cells. Thrombin- and activated protein C-mediated PAR-1 activation have unique effects on tumor cell biology. SUMMARY: Background Multiple studies have implicated protease-activated receptor-1 (PAR-1), a G-protein-coupled receptor activated by proteolytic cleavage of its N-terminus, as one target coupling thrombin-mediated proteolysis to tumor progression. Objective To analyze the role of PAR-1 in the setting of two distinct spontaneously developing tumor models in mice. Methods We interbred PAR-1-deficient mice with Transgenic Adenocarcinoma of the Mouse Prostate (TRAMP) mice, which spontaneously develop prostate tumors, and adenomatous polyposis coli Min (APCMin/+ ) mice, which spontaneously develop intestinal adenomas. Results Analyses of TRAMP mice with advanced disease (30 weeks) revealed that PAR-1 deficiency resulted in significantly larger and more aggressive prostate tumors. Prostates collected at an earlier time point (12 weeks of age) revealed that PAR-1 promotes apoptosis in transformed epithelia. In vitro analyses of TRAMP-derived cells revealed that activated protein C-mediated PAR-1 cleavage can induce tumor cell apoptosis, suggesting that tumor cell-intrinsic PAR-1 functions can limit tumor progression. Paralleling results in TRAMP mice, PAR-1-deficient APCMin/+ mice developed three-fold more adenomas than PAR-1-expressing mice, and the adenomas that formed were significantly larger. Moreover, loss of PAR-1 expression was shown to limit apoptosis in transformed intestinal epithelial cells. Conclusions Together, these results demonstrate a previously unrecognized role for PAR-1 in impeding tumor progression in vivo. These results also offer a cautionary note suggesting that long-term PAR-1 inhibition could increase malignancy risk in some contexts.

Mechanisms coupling thrombin to metastasis and tumorigenesis

The association of malignancy and thrombophilia is bidirectional, as evidenced by four decades of studies in animal models showing that hemostatic system components support cancer progression. Consistent with this view, clinical studies have suggested that anticoagulants not only limit thromboembolic complications associated with cancer, but also improve survival by impeding cancer progression, and may even prevent the development of cancer. In order to fully capitalize on this association, a detailed understanding of the mechanisms coupling hemostatic factors to cancer pathogenesis is required. Multiple studies have shown that thrombin-mediated procoagulant functions strongly promote metastatic potential. In particular, the platelet/fibrin(ogen) axis has been shown to protect newly formed micrometastases from innate immune surveillance, contribute to creation of a metastatic niche by recruitment of prometastatic inflammatory cells, and promote the epithelial to mesenchymal transition of metastatic cells. Thrombin-mediated functions have also been shown to support tumor growth in some contexts, and have even been linked to tumorigenesis in the setting of inflammation-driven colon cancer. Here, local thrombin-mediated extravascular fibrin deposition, and specifically fibrin-α_Mβ₂ integrin interaction, push intestinal inflammatory cells toward a pro-tumorigenic phenotype, resulting in the elaboration of key cytokines and growth factors that support the proliferation and survival of transformed intestinal epithelial cells. These studies reveal that hemostatic factors can serve as a bridge between pathological inflammation and the development of cancer. As a large proportion of cancers are caused by pathological inflammation, these studies suggest that therapies targeting the nexus between hemostasis and inflammation could be used to prevent cancer development.

Interleukin-18 Amplifies Macrophage Polarization and Morphological Alteration, Leading to Excessive Angiogenesis

M2 macrophage (Mφ) promotes pathologic angiogenesis through a release of pro-angiogenic mediators or the direct cell–cell interaction with endothelium in the micromilieu of several chronic inflammatory diseases, including rheumatoid arthritis and cancer, where interleukin (IL)-18 also contributes to excessive angiogenesis. However, the detailed mechanism remains unclear. The aim of this study is to investigate the mechanism by which M2 Mφs in the micromilieu containing IL-18 induce excessive angiogenesis in the in vitro experimental model using mouse Mφ-like cell line, RAW264.7 cells, and mouse endothelial cell line, b.End5 cells. We discovered that IL-18 acts synergistically with IL-10 to amplify the production of Mφ-derived mediators like osteopontin (OPN) and thrombin, yielding thrombin-cleaved form of OPN generation, which acts through integrins α4/α9, thereby augmenting M2 polarization of Mφ with characteristics of increasing surface CD163 expression in association with morphological alteration. Furthermore, the results of visualizing temporal behavior and morphological alteration of Mφs during angiogenesis demonstrated that M2-like Mφs induced excessive angiogenesis through the direct cell–cell interaction with endothelial cells, possibly mediated by CD163.

A Substrate-Selective Enzyme-Catalysis Assembly Strategy for Oligopeptide Hydrogel-Assisted Combinatorial Protein Delivery

Oligopeptide hydrogels for localized protein delivery have considerable potential to reduce systemic side effects but maximize therapeutic efficacy. Although enzyme catalysis to induce formation of oligopeptide hydrogels has the merits of unique regio- and enantioselectivity and mild reaction conditions, it may cause the impairment of function and activity of the encapsulated proteins by proteolytic degradation during gelation. Here we report a novel enzyme-catalysis strategy for self-assembly of oligopeptide hydrogels using an engineered protease nanocapsule with tunable substrate selectivity. The protease-encapsulated nanocapsule shielded the degradation activity of protease on the laden proteins due to the steric hindrance by the polymeric shell weaved around the protease, whereas the small-molecular precursors were easier to penetrate across the polymeric network and access the catalytic pocket of the protease to convert to the gelators for self-assembling hydrogel. The resulting oligopeptide hydrogels supported a favorable loading capacity without inactivation of both an antiangiogenic protein, hirudin and an apoptosis-inducing cytokine, TRAIL as model proteins. The hirudin and TRAIL coloaded oligopeptide hydrogel for combination cancer treatment showed enhanced synergistic antitumor effects both in vitro and in vivo.

A novel function of FoxO transcription factors in thrombin-stimulated vascular smooth muscle cell proliferation

Thrombin exerts coagulation-independent effects on the proliferation and migration of vascular smooth muscle cells (SMC). Forkhead box-O (FoxO) transcription factors regulate cell proliferation, apoptosis and cell cycle arrest, but a possible functional interaction between thrombin and FoxO factors has not been identified to date. In human cultured vascular SMC, thrombin induced a time-dependent phosphorylation of FoxO1 and FoxO3 but not FoxO4. This effect was mimicked by an activating-peptide (AP) for protease-activated receptor (PAR)-1, and abolished by a PAR-1 antagonist (SCH79797). APs for other PARs were without effect. FoxO1 and FoxO3 phosphorylation were prevented by the PI3 kinase (PI3K) inhibitor LY294002 while inhibitors of ERK1/2 (PD98059) or p38MAPK (SB203580) were ineffective. LY294002 moreover prevented thrombin-stimulated SMC mitogenesis and proliferation. FoxO1 and FoxO3 siRNA augmented basal DNA synthesis and proliferation of SMC. Nuclear content of FoxO proteins decreased time-dependently in response to thrombin, coincided with suppressed expression of the cell cycle regulating genes p21CIP1 and p27kip1 by thrombin. FoxO1 siRNA reduced basal p21CIP1 while FoxO3 siRNA attenuated p27kip1 expression; thrombin did not show additive effects. LY294002 restored p21CIP1 and p27kip1 protein expression. Immunohistochemistry revealed that human native and failed saphenous vein grafts were characterised by the cytosolic presence of p-FoxO factors in co-localisation of p21CIP1 and p27kip1 with SMC. In conclusion, thrombin and FoxO factors functionally interact through PI3K/Akt-dependent FoxO phosphorylation leading to expression of cell cycle regulating genes and ultimately SMC proliferation. This may contribute to remodelling and failure of saphenous vein bypass grafts.

Role of the Coagulation System in Genitourinary Cancers: Review

Tumor progression is associated with aberrant hemostasis, and patients with malignant diseases have an elevated risk of developing thrombosis. A crosstalk among the vascular endothelium, components of the coagulation cascade, and cancer cells transforms the intravascular milieu to a prothrombotic, proinflammatory, and cell-adhesive state. We review the existing evidence on activation of the coagulation system and its implication in genitourinary malignancies and discuss the potential therapeutic benefit of antithrombotic agents. A literature review was performed searching the Medline database and the Cochrane Library for original articles and reviews. A second search identified studies reporting on oncological benefit of anticoagulants in genitourinary cancer. An elevated expression of procoagulatory tissue factor on tumor cells and tumor-derived microparticles seems to stimulate cancer development and progression. Several components of the hemostatic system, including D-dimers, von Willebrand Factor, thrombin, fibrin-/ogen, soluble P-selectin, and prothrombin fragments 1 + 2 were either overexpressed or overactive in genitourinary cancers. Hypercoagulation was in general associated with a poorer prognosis. Experimental models and small trials in humans showed reduced cancer progression after treatment with anticoagulants. Main limitations of these studies were heterogeneous experimental methodology, small patient numbers, and a lack of prospective validation. In conclusion, experimental and clinical evidence suggests procoagulatory activity of genitourinary neoplasms, particularly in prostate, bladder and kidney cancer. This may promote the risk of vascular thrombosis but also metastatic progression. Clinical studies linked elevated biomarkers of hemostasis with poor prognosis in patients with genitourinary cancers. Thus, anticoagulation may have a therapeutic role beyond prevention of thromboembolism.

The effects of 1,4-dimethylpyridine in metastatic prostate cancer in mice

BACKGROUND

We previously showed that 1-methylnicotinamide (1-MNA) and its analog 1,4-dimethylpyridine (1,4-DMP) could inhibit the formation of lung metastases and enhance the efficacy of cyclophosphamide-based chemotherapy in the model of spontaneously metastasizing 4T1 mouse mammary gland tumors. In the present study, we aimed to investigate whether the previously observed activity of pyridine compounds pertains also to the prevention and the treatment of metastatic prostate tumors, in a combined chemotherapy with docetaxel.

METHODS

Cancer-preventing activity of 1,4-DMP was studied in the model of prostate tumors spontaneously arising in C57BL/6-Tg (TRAMP)8247Ng/J (TRAMP) mice. The efficacy of the combined chemotherapy, comprising simultaneous use of 1,4-DMP and docetaxel, was evaluated in the orthotopic mouse model of human PC-3M-luc2 prostate cancer. The toxicity of the applied treatment was also determined.

RESULTS

The development of prostate tumors in TRAMP mice remained unaffected after administration of 1,4-DMP. Similarly, no effect of 1,4-DMP was found on the growth of orthotopically transplanted PC-3M-luc2 tumors. However, when 1,4-DMP was administered along with docetaxel, it enhanced the anticancer activity of the chemotherapy. As a result, in PC-3M-luc2-bearing mice statistically significant inhibition of the tumor growth and lower metastases incidence were observed. The decreased metastatic yield is probably related to the diminished platelet activity observed in mice treated with combined therapeutic regimen. Finally, the combined treatment exhibited lowered side effects accompanying docetaxel administration.

CONCLUSIONS

Results presented herein confirm previously published data on the anticancer activity of pyridine compounds and demonstrate that 1,4-DMP may be beneficially implemented into chemotherapy utilizing various cytotoxic agents, directed against multiple metastatic tumor types.

Biological basis of personalized anticoagulation in cancer: oncogene and oncomir networks as putative regulators of coagulopathy

Activation of stromal response pathways in cancer is increasingly viewed as both a local and systemic extension of molecular alterations driving malignant transformation. Rather than reflecting passive and unspecific responses to anatomical abnormalities, the coagulation system is a target of oncogenic deregulation, impacting the role of clotting and fibrinolytic proteins, and integrating hemostasis, inflammation, angiogenesis and cellular growth effects in cancer. These processes signify, but do not depend on, the clinically manifest coagulopathy and thrombosis. In this regard, the role of driver mutations affecting oncoprotein coding genes such as RAS, EGFR or MET and tumour suppressors (PTEN, TP53) are well described as regulators of tissue factor (TF), protease activated receptors (PAR-1/2) and ectopic coagulation factors (FVII). Indeed, in both adult and pediatric brain tumours the expression patterns of coagulation and angiogenesis regulators (coagulome and angiome, respectively) reflect the molecular subtypes of the underlying diseases (glioblastoma or medulloblastoma) as defined by their oncogenic classifiers and clinical course. This emerging understanding is still poorly established in relation to the transforming effects of non-coding genes, including those responsible for the expression of microRNA (miR). Indeed, several miRs have been recently found to regulate TF and other effectors. We recently documented that in the context of the aggressive embryonal tumour with multilayered rosettes (ETMR) the oncogenic driver miR (miR-520g) suppresses the expression of TF and correlates with hypocoagulant tumour characteristics. Unlike in adult cancers, the growth of pediatric embryonal brain tumour cells as spheres (to maintain stem cell properties) results in upregulation of miR-520g and downregulation of TF expression and activity. We postulate that oncogenic protein and miR coding genes form alternative pathways of coagulation system regulation in different tumour settings, a property necessitating more personalised and biologically-based approaches to anticoagulation.

MicroRNA-379 suppresses osteosarcoma progression by targeting PDK1

Osteosarcoma is the most common primary bone tumour. Increasing evidence has demonstrated the pathogenic role of microRNA (miRNAs) dysregulation in tumour development. miR-379 was previously reported to function as an oncogenic or tumour-suppressing miRNA in a tissue-dependent manner. However, its function in osteosarcoma remains unknown. In this study, we found that the expression of miR-379 was downregulated in osteosarcoma tissues and cell lines. Further functional characterization revealed that miR-379 suppressed osteosarcoma cell proliferation and invasion in vitro and retarded the growth of osteosarcoma xenografts in vivo. Mechanistically, PDK1 was identified as the direct target of miR-379 in osteosarcoma, in which PDK1 expression was up-regulated and showed inverse correlation with miR-379. Enforced expression of PDK1 promoted osteosarcoma cell proliferation and rescued the anti-proliferative effect of miR-379. These data suggest that miR-379 could function as a tumour-suppressing miRNA via targeting PDK1 in osteosarcoma.

Dabigatran antagonizes growth, cell-cycle progression, migration, and endothelial tube formation induced by thrombin in breast and glioblastoma cell lines

Thrombin activates its G-coupled seven transmembrane protease-activated receptor (PAR-1) by cleaving the receptor's N-terminal end. In several human cancers, PAR1 expression and activation correlates with tumor progression and metastatization. This provides compelling evidence for the effectiveness of an appropriate antithrombin agent for the adjuvant treatment of patients with cancer. Dabigatran is a selective direct thrombin inhibitor that reversibly binds to thrombin. In this study, we aimed to explore if dabigatran may affect mechanisms favoring tumor growth by interfering with thrombin-induced PAR-1 activation. We confirmed that exposure of tumor cells to thrombin significantly increased cell proliferation and this was coupled with downregulation of p27 and concomitant induction of cyclin D1. Dabigatran was consistently effective in antagonizing thrombin-induced proliferation as well as it restored the baseline pattern of cell cycle protein expression. Thrombin significantly upregulated the expression of proangiogenetic proteins like Twist and GRO-α in human umbilical vascular endothelial cells (HUVEC) cells and their expression was significantly brought down to control levels when dabigatran was added to culture. We also found that the chemoattractant effect of thrombin on tumor cells was lost in the presence of dabigatran, and that the thrombin antagonist was effective in dampening vascular tube formation induced by thrombin. Our data support a role of thrombin in inducing the proliferation, migration, and proangiogenetic effects of tumor cells in vitro. Dabigatran has activity in antagonizing all these effects, thereby impairing tumor growth and progression. In vivo models may help to understand the relevance of this pathway.

Quantitative proteomic analysis exploring progression of colorectal cancer: Modulation of the serpin family

Colorectal cancer (CRC) remains a major cause of cancer related-death in developed countries. The mortality risk is correlated with the stage of CRC determined at the primary diagnosis and early diagnosis is associated with enhanced survival rate. Currently, only faecal occult blood tests are used to screen for CRC. Consequently, there is an incentive to identify specific markers of CRC. We used quantitative proteomic analysis of serum samples to characterize protein profiles in adenoma, CRC and healthy control samples. We identified 89 distinct proteins modulated between normal, colorectal adenoma and carcinoma patients. This list emphasizes proteins involved in enzyme regulator activities and in particular the serpin family. In serum samples, protein profiles of three members of the serpin family (SERPINA1, SERPINA3 and SERPINC1) were confirmed by ELISA assays. We obtained sensitivity/specificity values of 95%/95% for both SERPINA1 and SERPINC1, and 95%/55% for SERPINA3. This study supports the idea that serum proteins can discriminate adenoma and CRC patients from unaffected patients and reveals a panel of regulated proteins that might be useful for selecting patients for colonoscopy. By evaluating SERPINA1, SERPINA3 and SERPINC1, we highlight the potential role of the serpin family during the development and progression of CRC.

SIGNIFICANCE

Colorectal cancer (CRC) remains a major cause of cancer mortality throughout the world. However, very few CRC biomarkers have satisfactory sensitivity and specificity in clinical practice. To the best of our knowledge our study is the first to profile sera proteomes between adenoma, CRC and healthy patients. We report a comprehensive list of proteins that may be used as early diagnostic biomarkers of CRC. It is noteworthy that 17% of these modulated proteins have been previously described as candidate biomarkers in CRC. Enzyme regulator activity was found to be the main molecular function among these proteins and, in particular, there was an enrichment of members of the serpin family. The subsequent verification on a new cohort by ELISA demonstrates that these serpins could be useful to discriminate healthy from colorectal carcinoma patients with a high sensitivity and specificity. The combination of these biomarkers should increase predictive powers of CRC diagnosis. The remaining candidates form a reserve for further evaluation of additional biomarkers for CRC diagnosis.

Limiting prothrombin activation to meizothrombin is compatible with survival but significantly alters hemostasis in mice

Thrombin-mediated proteolysis is central to hemostatic function but also plays a prominent role in multiple disease processes. The proteolytic conversion of fII to α-thrombin (fIIa) by the prothrombinase complex occurs through 2 parallel pathways: (1) the inactive intermediate, prethrombin; or (2) the proteolytically active intermediate, meizothrombin (fIIa(MZ)). FIIa(MZ) has distinct catalytic properties relative to fIIa, including diminished fibrinogen cleavage and increased protein C activation. Thus, fII activation may differentially influence hemostasis and disease depending on the pathway of activation. To determine the in vivo physiologic and pathologic consequences of restricting thrombin generation to fIIa(MZ), mutations were introduced into the endogenous fII gene, resulting in expression of prothrombin carrying 3 amino acid substitutions (R157A, R268A, and K281A) to limit activation events to yield only fIIa(MZ) Homozygous fII(MZ) mice are viable, express fII levels comparable with fII(WT) mice, and have reproductive success. Although in vitro studies revealed delayed generation of fIIa(MZ) enzyme activity, platelet aggregation by fII(MZ) is similar to fII(WT) Consistent with prior analyses of human fIIa(MZ), significant prolongation of clotting times was observed for fII(MZ) plasma. Adult fII(MZ) animals displayed significantly compromised hemostasis in tail bleeding assays, but did not demonstrate overt bleeding. More notably, fII(MZ) mice had 2 significant phenotypic advantages over fII(WT) animals: protection from occlusive thrombosis after arterial injury and markedly diminished metastatic potential in a setting of experimental tumor metastasis to the lung. Thus, these novel animals will provide a valuable tool to assess the role of both fIIa and fIIa(MZ) in vivo.

Colon Cancer Growth and Dissemination Relies upon Thrombin, Stromal PAR-1, and Fibrinogen

Thrombin-mediated proteolysis is a major determinant of metastasis, but is not universally important for primary tumor growth. Here, we report that colorectal adenocarcinoma represents one important exception whereby thrombin-mediated functions support both primary tumor growth and metastasis. In contrast with studies of multiple nongastrointestinal cancers, we found that the growth of primary tumors formed by murine and human colon cancer cells was reduced in mice by genetic or pharmacologic reduction of circulating prothrombin. Reduced prothrombin expression was associated with lower mitotic indices and invasion of surrounding tissue. Mechanistic investigations revealed that thrombin-driven colonic adenocarcinoma growth relied upon at least two targets of thrombin-mediated proteolysis, protease-activated receptor-1 (PAR-1) expressed by stromal cells and the extracellular matrix protein, fibrinogen. Colonic adenocarcinoma growth was reduced in PAR-1-deficient mice, implicating stromal cell-associated PAR-1 as one thrombin target important for tumor outgrowth. Furthermore, tumor growth was dramatically impeded in fibrinogen-deficient mice, offering the first direct evidence of a critical functional role for fibrinogen in malignant tumor growth. Tumors harvested from fibrinogen-deficient mice displayed a relative reduction in cell proliferative indices, as well as increased tumor necrosis and decreased tumor vascular density. Collectively, our findings established a functional role for thrombin and its targets PAR-1 and fibrinogen in the pathogenesis of colonic adenocarcinoma, supporting tumor growth as well as local invasion and metastasis.

Expression of MMP-1/PAR-1 and patterns of invasion in oral squamous cell carcinoma as potential prognostic markers

Background

Matrix metalloproteinase (MMP)-1 degrades type I collagen of the extracellular matrix and also activates protease activated receptor (PAR)-1 to induce angiogenesis. The aims of this study were to evaluate microvessel density (MVD) and the expression of PAR-1 and MMP-1 in oral squamous cell carcinoma (SCC) specimens with different patterns of invasion (POI) and to evaluate their association with clinical outcomes.

Methods

Seventy-four surgically obtained oral SCC samples were classified by POI according to hematoxylin-eosin staining. MVD and the localization and intensity of PAR-1 and MMP-1 expression were detected by immunohistochemistry.

Results

Of the 74 oral SCC samples, 18, 5, 34, and 17 showed type I, II, III, and IV POI, respectively. MVD and expression levels of MMP-1 and PAR-1 differed between POI types I–II and POI types III–IV. Patients with low tumor expression of MMP-1 and PAR-1 and low MVD had a longer survival time than those with high tumor expression of MMP-1 and PAR-1. Moreover, the survival time of patients with POI types III–IV was shorter than that of patients with POI types I–II.

Conclusion

POI combined with expression levels of MMP-1 and PAR-1 may be a valuable tool for assessing the clinical prognosis of patients with oral SCC.

PTEN plays an important role in thrombin-mediated lung cancer cell functions

Thrombin and its membrane receptor, protease-activated receptor 1 (PAR1), have been reported to promote the development of lung cancer in vitro and in vivo. However, the intracellular molecular mechanism or signaling pathway that mediates the cytological effects after the thrombin-receptor interaction is poorly understood. Our previous study observed that the expression of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) was downregulated in thrombin-stimulated lung cancer. In this study, the role of PTEN in thrombin-mediated cell function and the corresponding cell signaling pathway were studied in lung cancer cell Glc-82. The results indicated that thrombin downregulates the PTEN expression level and that PTEN plays an important role in thrombin-mediated Glc-82 functions, including cell cycle progression, cell apoptosis, and cell migration. The PI3K/AKT signaling pathway and its related proteins, including p27 and S phase kinase associated protein 2 (Skp2), are involved in the effects induced by PTEN downregulation. PAR1 plays a role in thrombin-mediated reduction of PTEN expression. This study suggested that the PTEN/PI3K/AKT signaling pathway plays an important role in thrombin/PAR1-mediated lung cancer cell growth and migration.

Microdissecting the role of microRNAs in the pathogenesis of prostate cancer

MicroRNAs (miRNAs) are naturally occurring, small, non-coding RNA molecules that post-transcriptionally regulate the expression of a large number of genes involved in various biological processes, either through mRNA degradation or through translation inhibition. Since the discovery of miRNAs, a vast amount of research has implicated the deregulated expression of miRNAs in different malignancies, including prostate cancer (PCa). Different miRNA expression profiles are reportedly associated with the development, progression, and emergence of castration-resistant PCa (CRPC), suggesting their use in the diagnosis, prognosis, and development of anti-cancer treatment models directed against this disease. However, before their exploitation in terms of therapeutics, a thorough understanding and in-depth mechanistic studies of these miRNAs and the gene networks they orchestrate are necessary for ascertaining their definitive role in the development and progression of PCa. This review attempts to extensively summarize the current knowledge of aberrantly expressed miRNAs and their mode of action in PCa, while highlighting the existing discrepancies and future research warranted.

NETosis: a new factor in tumor progression and cancer-associated thrombosis

Neutrophils have long been known as innate immune cells that phagocytose and kill pathogens and mount inflammatory responses protecting the host from infection. In the past decades, new aspects of neutrophils have emerged unmasking their importance not only in inflammation but also in many pathological conditions including thrombosis and cancer. The 2004 discovery that neutrophils, upon strong activation, release decondensed chromatin to form neutrophil extracellular traps (NETs), has unveiled new avenues of research. Here, we review current knowledge regarding NETs in thrombosis, with a special focus on cancer-associated thrombosis as well as their potential role in cancer growth and metastasis. We discuss the prospective use of NET-specific biomarkers, such as citrullinated histone H3 and NET inhibitors, as tools to anticipate and fight cancer-associated thrombosis. We propose that the rapid developments in the field of NETosis may provide new targets to combat the thrombotic consequences of cancer and perhaps even help to contain the disease itself.

Analysis of expression of microRNAs and genes involved in the control of key signaling mechanisms that support or inhibit development of brain tumors of different grades

BACKGROUND

MicroRNAs (miRNAs) are a class of small non-coding RNA molecules involved in the regulation of key biological processes. Different miRNAs with pro-oncogenic and anti-oncogenic properties have been identified in glioblastomas. We decided to analyze expression profiles of 10 mature miRNAs (miR-7-1, miR-10а, miR-17, miR-20а, miR-21, miR-23а, miR-26а, miR-137, and miR-222) in post-surgery glioma specimens of different grades in order to find whether the expression level correlates with tumor grades. We also measured expression of six key genes such as PTEN, p21/CDKN1A, MDR1, ABCG2, BAX, and BCL-2 involved in the regulation of critical glioma signaling pathways to establish the effect of miRNAs on these signaling mechanisms.

METHODS

Using RT-PCR, we performed expression analysis of 25 tumor fresh samples (grades II-IV).

RESULTS

We found gradual increase in miR-21 and miR-23a levels in all tumor grades whereas miR-7 and miR-137 were significantly down-regulated depending on the glioma grade. MDR, ABCG2, and p21/CDKN1A levels were significantly up-regulated while expression of PTEN was down-regulated in tumor samples compared to the normal brain tissue.

CONCLUSIONS

These observations provide new insights into molecular pathogenic mechanisms of glioma progression and suggest about a potential value of miRNAs as a putative diagnostic marker of brain tumors.

Pathologies at the nexus of blood coagulation and inflammation: thrombin in hemostasis, cancer, and beyond

Thrombin is the protease involved in blood coagulation. Its deregulation can lead to hemostatic abnormalities, which range from subtle subclinical to serious life-threatening coagulopathies, i.e., during septicemia. Additionally, thrombin plays important roles in many (patho)physiological conditions that reach far beyond its well-established role in stemming blood loss and thrombosis, including embryonic development and angiogenesis but also extending to inflammatory processes, complement activation, and even tumor biology. In this review, we will address thrombin's broad roles in diverse (patho)physiological processes in an integrative way. We will also discuss thrombin as an emerging major target for novel therapies.

Roles of microRNAs during prostatic tumorigenesis and tumor progression

Prostate cancer (PCa) is considered to be a frequently diagnosed cancer in males with high mortality worldwide, but the molecular mechanism responsible for prostate tumorigenesis and progression remains unclear. Increasing evidence has shown that microRNAs (miRNAs) play an important role in PCa. In this review, we focus on the current advances about the role of miRNAs in regulating tumorigenesis and progression of PCa, mainly in suppressing or promoting PCa growth and metastasis, and maintaining the pluripotency of PCa stem cells (PCSC). More studies on miRNAs will provide a better understanding of their regulatory mechanisms in PCa.

Tanshinone IIA inhibits hypoxia-induced pulmonary artery smooth muscle cell proliferation via Akt/Skp2/p27-associated pathway

We previously showed that tanshinone IIA ameliorated the hypoxia-induced pulmonary hypertension (HPH) partially by attenuating pulmonary artery remodeling. The hypoxia-induced proliferation of pulmonary artery smooth muscle cells (PASMCs) is one of the major causes for pulmonary arterial remodeling, therefore the present study was performed to explore the effects and underlying mechanism of tanshinone IIA on the hypoxia-induced PASMCs proliferation. PASMCs were isolated from male Sprague-Dawley rats and cultured in normoxic (21%) or hypoxic (3%) condition. Cell proliferation was measured with 3 - (4, 5 - dimethylthiazal - 2 - yl) - 2, 5 - diphenyltetrazoliumbromide assay and cell counting. Cell cycle was measured with flow cytometry. The expression of of p27, Skp-2 and the phosphorylation of Akt were measured using western blot and/or RT-PCR respectively. The results showed that tanshinone IIA significantly inhibited the hypoxia-induced PASMCs proliferation in a concentration-dependent manner and arrested the cells in G1/G0-phase. Tanshinone IIA reversed the hypoxia-induced reduction of p27 protein, a cyclin-dependent kinase inhibitor, in PASMCs by slowing down its degradation. Knockdown of p27 with specific siRNA abolished the anti-proliferation of tanshinone IIA. Moreover, tanshinone IIA inhibited the hypoxia-induced increase of S-phase kinase-associated protein 2 (Skp2) and the phosphorylation of Akt, both of which are involved in the degradation of p27 protein. In vivo tanshinone IIA significantly upregulated the hypoxia-induced p27 protein reduction and downregulated the hypoxia-induced Skp2 increase in pulmonary arteries in HPH rats. Therefore, we propose that the inhibition of tanshinone IIA on hypoxia-induce PASMCs proliferation may be due to arresting the cells in G1/G0-phase by slowing down the hypoxia-induced degradation of p27 via Akt/Skp2-associated pathway. The novel information partially explained the anti-remodeling property of tanshinone IIA on pulmonary artery in HPH.

Thrombin stimulation of inflammatory breast cancer cells leads to aggressiveness via the EGFR-PAR1-Pak1 pathway

Inflammatory breast cancer (IBC) accounts for a small fraction but aggressive form of epithelial breast cancer. Although the role of thrombin in cancer is beginning to be unfolded, its impact on the biology of IBC remains unknown. The purpose of this study was to establish the role of thrombin on the invasiveness of IBC cells. The IBC SUM149 cell line was treated with thrombin in the absence or presence of the epidermal growth factor receptor (EGFR) inhibitor erlotinib and protease-activated receptor 1 (PAR1) inhibitor. The effects of pharmacological inhibitors on the ability of thrombin to stimulate the growth rate and invasiveness were examined. We found that the inhibition of putative cellular targets of thrombin action suppresses both the growth and invasiveness of SUM149 cells in a concentration-dependent manner. In addition, thrombin-mediated increased invasion of SUM149 cells was routed through EGFR phosphorylation, and in turn, stimulation of the p21-activated kinase (Pak1) activity in a EGFR-sensitive manner. Interestingly, thrombin-mediated activation of the Pak1 pathway stimulation was blocked by erlotinib and PAR1 inhibitor. For proof-of-principle studies, we found immunohistochemical evidence of Pak1 activation as well as expression of PAR1 in IBC. Thrombin utilizes EGFR to relay signals promoting SUM149 cell growth and invasion via the Pak1 pathway. The study provides the rationale for future therapeutic approaches in mitigating the invasive nature of IBC by targeting Pak1 and/or EGFR.

The role and clinical implications of microRNAs in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is common and one of the most aggressive of all human cancers. Recent studies have indicated that miRNAs, a class of small noncoding RNAs that regulate gene expression post-transcriptionally, directly contribute to HCC by targeting many critical regulatory genes. Several miRNAs are involved in hepatitis B or hepatitis C virus replication and virus-induced changes, whereas others participate in multiple intracellular signaling pathways that modulate apoptosis, cell cycle checkpoints, and growth-factor-stimulated responses. When disturbed, these pathways appear to result in malignant transformation and ultimately HCC development. Recently, miRNAs circulating in the blood have acted as possible early diagnostic markers for HCC. These miRNA also could serve as indicators with respect to drug efficacy and be prognostic in HCC patients. Such biomarkers would assist stratification of HCC patients and help direct personalized therapy. Here, we summarize recent advances regarding the role of miRNAs in HCC development and progression. Our expectation is that these and ongoing studies will contribute to the understanding of the multiple roles of these small noncoding RNAs in liver tumorigenesis.

Prognostic significance of antithrombin III levels for outcomes in patients with hepatocellular carcinoma after curative hepatectomy

BACKGROUND

Although several studies have shown that serum antithrombin III (ATIII) has anti-inflammatory effects, the prognostic value of ATIII in HCC is unknown. We investigated the influence of preoperative ATIII levels on the outcome of patients who underwent hepatectomy for hepatocellular carcinoma (HCC).

METHODS

Data from 440 patients (314 patients with ATIII ≥ 70 % and 126 patients with ATIII <70 %) who underwent curative hepatectomy for HCC were retrospectively collected and analyzed. To overcome bias due to the different distribution of covariates for the 2 groups, propensity score matching was performed on the patients, and outcomes were compared.

RESULTS

The propensity score analysis revealed that 65 patients with ATIII of ≥ 70 % (group 1) and 65 patients with ATIII of <70 % (group 2) had the same preoperative and operative characteristics (excluding the ATIII level). The overall survival rate and the disease-free survival rate was significantly higher in group 1 than in group 2 (P = 0.005 and 0.011, respectively). Multivariate analysis showed that ATIII was a significant favorable factor for overall survival and disease-free survival of patients with HCC after curative hepatectomy.

CONCLUSIONS

The prognosis of patients with HCC was found to be associated with preoperative antithrombin III levels. ATIII may be useful for predicting outcomes of patients with HCC after curative hepatectomy.

MetastamiRs: non-coding MicroRNAs driving cancer invasion and metastasis

MicroRNAs (miRNAs) are small non-coding RNAs of ~22 nucleotides that function as negative regulators of gene expression by either inhibiting translation or inducing deadenylation-dependent degradation of target transcripts. Notably, deregulation of miRNAs expression is associated with the initiation and progression of human cancers where they act as oncogenes or tumor suppressors contributing to tumorigenesis. Abnormal miRNA expression may provide potential diagnostic and prognostic tumor biomarkers and new therapeutic targets in cancer. Recently, several miRNAs have been shown to initiate invasion and metastasis by targeting multiple proteins that are major players in these cellular events, thus they have been denominated as metastamiRs. Here, we present a review of the current knowledge of miRNAs in cancer with a special focus on metastamiRs. In addition we discuss their potential use as novel specific markers for cancer progression.

Skp2: a novel potential therapeutic target for prostate cancer

Prostate cancer is the most frequently diagnosed tumor in men and the second most common cause of cancer-related death for males in the United States. It has been shown that multiple signaling pathways are involved in the pathogenesis of prostate cancer, such as androgen receptor (AR), Akt, Wnt, Hedgehog (Hh) and Notch. Recently, burgeoning amounts of evidence have implicated that the F-box protein Skp2 (S-phase kinase associated protein 2), a well-characterized oncoprotein, also plays a critical role in the development and progression of prostate cancer. Therefore, this review discusses the recent literature regarding the function and regulation of Skp2 in the pathogenesis of prostate cancer. Furthermore, we highlight that Skp2 may represent an attractive therapeutic target, thus warrants further development of agents to target Skp2, which could have significant therapeutic impact on prostate cancer.

Tissue factor, blood coagulation, and beyond: an overview

Emerging evidence shows a broad spectrum of biological functions of tissue factor (TF). TF classical role in initiating the extrinsic blood coagulation and its direct thrombotic action in close relation to cardiovascular risks have long been established. TF overexpression/hypercoagulability often observed in many clinical conditions certainly expands its role in proinflammation, diabetes, obesity, cardiovascular diseases, angiogenesis, tumor metastasis, wound repairs, embryonic development, cell adhesion/migration, innate immunity, infection, pregnancy loss, and many others. This paper broadly covers seminal observations to discuss TF pathogenic roles in relation to diverse disease development or manifestation. Biochemically, extracellular TF signaling interfaced through protease-activated receptors (PARs) elicits cellular activation and inflammatory responses. TF diverse biological roles are associated with either coagulation-dependent or noncoagulation-mediated actions. Apparently, TF hypercoagulability refuels a coagulation-inflammation-thrombosis circuit in “autocrine” or “paracrine” fashions, which triggers a wide spectrum of pathophysiology. Accordingly, TF suppression, anticoagulation, PAR blockade, or general anti-inflammation offers an array of therapeutical benefits for easing diverse pathological conditions.

p27(Kip1) deficiency promotes prostate carcinogenesis but does not affect the efficacy of retinoids in suppressing the neoplastic process

BACKGROUND

p27 is a cell cycle suppressor gene, whose protein is a negative regulator of cyclin/cdk complexes. p27 is also a potential target of retinoids in cancer prevention studies. In benign prostate hyperplasia (BPH), and in most carcinomas, p27(Kip1) is down-regulated, suggesting its potential resistance to retinoids. To test this hypothesis, we examined the efficacy of 9-cis retinoic acid (9cRA) to suppress prostate cell proliferation (PECP) and carcinogenesis in p27(Kip1) deficient mice.

METHODS

p27(Kip1) deficient (-/-), heterozygous (+/-) and homozygous (+/+) mice were treated for 7 days with testosterone, 9cRA, or with both, and cell proliferation in dorsolateral prostate (DLP) was determined by BrdU labeling. Prostate carcinogenesis was induced by N-Methyl-N-Nitrosourea (MNU) and hormone stimulation.

RESULTS

PECP in DLP of two-month-old mice of all genotypes was similar but significantly increased in old p27-/- mice only. Testosterone treatment increased PECP in all three p27 genotypes with the highest values in p27-/- mice. p27(Kip1) deficiency did not affect the response of PEC to 9cRA and to 9cRA+testosterone. The decrease of p27(Kip1) in p27+/- and p27-/- mice progressively increased the incidence and frequency of PIN and tumors. 9cRA suppressed PIN in all three p27 genotypes and this was associated with decreased PECP and increased cellular senescence.

CONCLUSIONS

This data indicates that p27(Kip1) deficiency promotes prostate cell proliferation and carcinogenesis but does not affect 9cRA's potential to suppress prostate carcinogenesis, suggesting that patients with PIN and carcinomas lacking or having a low level of p27(Kip1) expression may also benefit from clinical trials with retinoids.

Oral thrombostatin FM19 inhibits prostate cancer

Thrombin stimulates proliferation, invasion and metastasis by cleaving protease-activated receptor 1 (PAR1) on human prostate cancer cells. Current direct thrombin inhibitors pose risks for bleeding in the cancer patients. We have developed an oral reversible direct thrombin inhibitor called FM19. FM19 inhibits thrombin-induced calcium mobilisation of PC3 cells with an IC50 of 15 μM with a 95% confidence interval of 7.3-31.6 μM. Thrombin stimulation increases PC3 cell invasion three-fold from 27.1 ± 11.4 to 66 ± 11.6. FM19 or bivalirudin reduces cell invasion at ≥0.1 μM (p≤0.02). After inoculation with PC3 cells, nude mice were treated with oral FM19 at 3 mg/ml in the drinking water. The treated mice did not have long bleeding times and only a 1.4-fold increase in their thrombin clotting time. However, with treatment, the mice have a reduced rate of tumour growth 0.26 ± 0.17 fold change/day vs. 0.55 ± 0.35 for untreated (p = 0.038), reduced fold change in tumour size 5.3 ± 0.47 to 8.9 ± 1.8 (untreated) (p=0.048), and reduced overall tumour weight 0.5 ± 0.31 g vs. 0.82 ± 0.32 g (untreated) (p=0.04). On microscopic examination, FM19 treatment reduces the number of large vessels in the tumours from 4.6 ± 2.1 per high-powered field in untreated samples to 1.4 ± 1.4 in treated samples (p≤0.04). These studies show FM19 reduces prostate tumour growth in vivo at a concentration below that needed for anticoagulation. These data suggest novel opportunities for oral direct thrombin inhibitors in cancer therapy.

Protease-activated receptors mediate crosstalk between coagulation and fibrinolysis

The coagulation and fibrinolytic systems contribute to malignancy by increasing angiogenesis, tumor growth, tumor invasion, and tumor metastasis. Oncogenic transformation increases the expression of tissue factor (TF) that results in local generation of coagulation proteases and activation of protease-activated receptor (PAR)-1 and PAR-2. We compared the PAR-dependent expression of urokinase plasminogen activator (uPA) and plasminogen activator inhibitor (PAI)-1 in 2 murine mammary adencocarcinoma cell lines: metastatic 4T1 cells and nonmetastatic 67NR cells. 4T1 cells expressed TF, PAR-1 and PAR-2 whereas 67NR cells expressed TF and PAR-1. We also silenced PAR-1 or PAR-2 expression in the 4T1 cells. We discovered 2 distinct mechanisms for PAR-dependent expression of uPA and PAI-1. First, we found that factor Xa or thrombin activation of PAR-1 led to a rapid release of stored intracellular uPA into the culture supernatant. Second, thrombin transactivation of a PAR-1/PAR-2 complex resulted in increases in PAI-1 mRNA and protein expression. Cells lacking PAR-2 failed to express PAI-1 in response to thrombin and factor Xa did not activate the PAR-1/PAR-2 complex. Our results reveal how PAR-1 and PAR-2 on tumor cells mediate crosstalk between coagulation and fibrinolysis.

The function of microRNAs, small but potent molecules, in human prostate cancer

Prostate cancer is one of the most significant cancers of men all over the world. The microRNAs (miRNAs) possess crucial functions in pathogenesis of the disease and its gain of androgen independency. The miRNAs are small, approximately 18-24 nucleotides, non-coding, endogenously synthesized RNAs that regulate gene expression post-transcriptionally. They are found in viruses, plants, and animal cells. The miRNAs have critical functions in gene expression and their dysregulation may cause tumor formation and progression of several diseases. Here, we have reviewed the most current literature to elucidate the function of miRNAs in human prostate cancer. We believe that this will help investigators not only working in prostate cancer, but also studying the miRNAs in other diseases to delineate the functions of miRNAs implicated in human prostate cancer development and progression.

Thrombin regulates the metastatic potential of human rhabdomyosarcoma cells: distinct role of PAR1 and PAR3 signaling

We observed that human rhabdomyosarcoma (RMS) cells highly express a tissue factor that promotes thrombin formation, which indirectly and directly affects RMS progression. First, we found that thrombin activates platelets to generate microvesicles (PMV), which transfer to RMS cells' alpha2beta3 integrin and increase their adhesiveness to endothelial cells. Accordingly, RMS cells covered with PMVs showed higher metastatic potential after i.v. injection into immunodeficient mice. Furthermore, PMVs activate mitogen-activated protein kinase (MAPK)p42/44 and AKT to chemoattract RMS cells. We also found that RMS cells express functional protease-activated receptor-1 (PAR1) and PAR3 and respond to thrombin stimulation by MAPKp42/44 and MAPKp38 phosphorylation. To our surprise, thrombin did not affect RMS proliferation or survival; it inhibited the chemotactic and adhesive properties of RMS cells. However, when PAR1-specific agonist thrombin receptor-activating peptide 6 was used, which does not activate PAR3, selective PAR1 stimulation enhanced RMS proliferation. To learn more on the role of PAR1 and PAR3 antagonism in RMS proliferation and metastasis, we knocked down both receptors by using a short hairpin RNA strategy. We found that although thrombin does not affect growth of PAR1(-/-) cells, it stimulated the proliferation of PAR3(-/-) cells. More importantly, PAR3(-/-) cells, in contrast to PAR1(-/-) ones, formed larger tumors in immunodeficient mice. We conclude that thrombin is a novel underappreciated modulator of RMS metastasis and that we have identified a novel role for PAR3 in thrombin signaling.

Review of cellular and molecular pathways linking thrombosis and innate immune system during sepsis

Cellular and molecular pathways link thrombosis and innate immune system during sepsis. Extrinsic pathway activation of protease thrombin through FVIIa and tissue factor (TF) in sepsis help activate its endothelial cell (EC) membrane Protease Activated Receptor 1 (PAR-1). Thrombin adjusts the EC cycle through activation of G proteins (G12/13), and later through Rho GEFs (guanine nucleotide exchange factors), and provides a path for Rho GTPases mediated cytoskeletal responses involved in shape change and permeability of the EC membrane leading to an increase of leakage of plasma proteins.At the same time, thrombin stimulates spontaneous mitogenesis by inducing activation of the cell cycle from G0-G1 to S by down-regulation of p27Kip1, a negative regulator of the cell cycle, in association with the up-regulation of S-phase kinase associated protein 2 (Skp2). After transport in cytoplasm, p27 Kip1 binds to RhoA thus prevent activation of RhoA by GEFs, thus inhibit GDP-GTP exchange mediated by GEFs. In cytoplasm, releasing factor (RF) p27-RF-Rho is able to free RhoA. P27 RF-Rho binds p27kip1 and prevents p27kip1 from binding to RhoA. Exposed RhoA is later able to increase the expression of the F-box protein Skp2, after its Akt triggered 14-3-3-β-dependent cytoplasm relocation. Skp2 increases cytoplasm ubiquitination-dependent degradation of p27Kip1. Additionally, after septic induction of canonical NF-kB pathway in EC through TLR4/IRAK4/TRAF/IkB, an IKKα dimer phosphorylates the p52 precursor NF-kB2/p100, leading to p100 processing and translocation of RelB/p52 to the nucleus. By controlling the NF-kB-RelB complex, IKKα signaling regulates the transcription of the Skp2 and correspondingly p27Kip1.

MicroRNA-222 regulates cell invasion by targeting matrix metalloproteinase 1 (MMP1) and manganese superoxide dismutase 2 (SOD2) in tongue squamous cell carcinoma cell lines

MicroRNA deregulation is involved in tumor initiation and progression. The aim of this study was to identify and validate the microRNA candidates that contribute to the metastasis of oral tongue squamous cell carcinoma (OTSCC). Using microarrays, a panel of differentially expressed microRNAs was identified in paired OTSCC cell lines with different metastatic potential. Selected microRNA candidates (including hsa-miR-222) were further validated using quantitative PCR approach. Functional analysis indicated that hsa-miR-222 inhibits OTSCC cell invasion. Ectopic transfection of hsa-miR-222 reduced the expression of MMP1 and SOD2 in OTSCC cell lines. Direct targeting of hsa-miR-222 to specific sequences located in the 3'-untranslated regions of both MMP1 and SOD2 mRNAs were confirmed using luciferase reporter gene assays. Furthermore, SOD2 knockdown by siRNA led to the downregulation of MMP1 expression. Taken together, these results suggested that hsa-miR-222 regulates the MMP1 expression through both direct cis-regulatory mechanism (targeting MMP1 mRNA) and indirect trans-regulatory mechanism (indirect controlling of MMP1 gene expression by targeting SOD2). Our results indicate that hsa-miR-222 plays an important role in OTSCC invasion, and may serve as a novel therapeutic target for OTSCC patients at risk of metastatic disease.