Fibrinogen-derived fibrinostatin inhibits tumor growth through anti-angiogenesis

Novel prognostic score based on the preoperative total bilirubin-albumin ratio and fibrinogen-albumin ratio in ampullary adenocarcinoma

BACKGROUND

The preoperative total bilirubin-albumin ratio (TBAR) and fibrinogen-albumin ratio (FAR) have been proven to be valuable prognostic factors in various cancers.

AIM

To detect the prognostic value of TBAR and FAR in ampullary adenocarcinoma (AC) patients who underwent curative pancreaticoduodenectomy.

METHODS

AC patients who underwent curative pancreaticoduodenectomy in the National Cancer Center of China between 1998 and 2020 were retrospectively reviewed. The prognostic cutoff values of TBAR and FAR were determined through the best survival separation model. Then, a novel prognostic score combining TBAR and FAR was calculated and validated through the logistic regression analysis and Cox regression analysis.

RESULTS

A total of 188 AC patients were enrolled in the current study. The best cutoff values of TBAR and FAR for predicting overall survival were 1.7943 and 0.1329, respectively. AC patients were divided into a TBAR-low group (score = 0) vs a TBAR-high group (score = 1) and a FAR-low group (score = 0) vs a FAR-high group (score = 1). The total score was calculated as a novel prognostic factor. Multivariable logistic regression analysis revealed that a high score was an independent protective factor for recurrence [score = 1 vs score = 0: Odds ratio (OR) = 0.517, P = 0.046; score = 2 vs score = 0 OR = 0.236, P = 0.038]. In addition, multivariable survival analysis also demonstrated that a high score was an independent protective factor in AC patients (score = 2 vs score = 0: Hazard ratio = 0.230, P = 0.046).

CONCLUSION

A novel prognostic score based on preoperative TBAR and FAR has been demonstrated to have good predictive power in AC patients who underwent curative pancreaticoduodenectomy. However, more studies with larger samples are needed to validate this conclusion.

Combination of preoperative fibrinogen and D-dimer as a prognostic indicator in pancreatic ductal adenocarcinoma patients undergoing R0 resection

BACKGROUND

Patients with malignant tumors frequently exhibit hyperactivation of the coagulation system and secondary increased fibrinolytic activity. Fibrinogen and D-dimer are common indicators that are crucial in the coagulation/fibrinolysis system. Both indicators have been verified to have predictive value in the overall survival (OS) of many patients with solid malignancies.

AIM

To explore the prognostic significance of fibrinogen combined with D-dimer in pancreatic ductal adenocarcinoma (PDAC) patients undergoing radical R0 resection.

METHODS

We retrospectively analyzed the clinical data of 282 patients with PDAC undergoing radical R0 resection in the Cancer Hospital, Chinese Academy of Medical Sciences, between January 2010 and December 2019. The surv_cutpoint function of R language was used to determine the optimal cutoff values of the preoperative fibrinogen concentration and preoperative D-dimer concentration. Enrolled patients were further divided into the any-high group (high preoperative fibrinogen concentration and/or high preoperative D-dimer concentration) and the low-low group (low preoperative fibrinogen and D-dimer concentrations) according to the optimal cutoff values.

RESULTS

The optimal cutoff values of the preoperative fibrinogen concentration and preoperative D-dimer concentration were 3.31 g/L and 0.53 mg/L, respectively. Furthermore, multivariate Cox regression analysis showed that the preoperative fibrinogen concentration (HR: 1.603, 95%CI: 1.201-2.140, P = 0.001) and preoperative D-dimer concentration (HR: 1.355, 95%CI: 1.019-1.801, P = 0.036) exhibited obvious correlations with the OS of PDAC patients undergoing radical R0 resection. A prognostic analysis was further performed based on the subgroup results by using fibrinogen combined with D-dimer. The median OS duration of the low-low group (31.17 mo) was significantly longer than that of the any-high group (15.43 mo). Additionally, multivariate Cox regression analysis revealed that the degree of differentiation (P < 0.001), lymph node metastasis (HR: 0.663, 95%CI: 0.497-0.883, P = 0.005), preoperative CA19-9 level (HR: 1.699, 95%CI: 1.258-2.293, P = 0.001), adjuvant therapy (HR: 1.582, 95%CI: 1.202-2.081, P = 0.001) and preoperative combined grouping (HR: 2.397, 95%CI: 1.723-3.335, P < 0.001) were independent predictors of OS in PDAC patients undergoing radical R0 resection.

CONCLUSION

Preoperative fibrinogen combined with D-dimer plays a predictive role in OS, and low preoperative fibrinogen and D-dimer concentrations can indicate prolonged OS in PDAC patients undergoing radical R0 resection.

Research Progress of Preoperative FPR, FAR or AFR in Patients with Colorectal Cancer

Research has confirmed that plasma albumin (Alb), prealbumin (PA) and fibrinogen (Fib) are involved in regulating the occurrence and development of various tumors. Their levels in peripheral blood are related to the survival outcome and treatment response of patients, but the accuracy and specificity of single application have yet to be fully realized. A growing amount of evidence indicates that predictors such as preoperative fibrinogen to prealbumin ratio (FPR), fibrinogen to albumin ratio (FAR) or albumin to fibrinogen ratio (AFR) are emerging as comprehensive indicators. Indeed, their components play a key regulatory role in the progression of colorectal cancer (CRC). Preoperative FPR, FAR or AFR levels, therefore, are expected to become new biomarkers for prognosis evaluation and curative effect prediction for CRC patients and are significant in the guidance they could provide for the development of individualized treatment strategies.

Pretreatment Albumin-to-Fibrinogen Ratio Independently Predicts Chemotherapy Response and Prognosis in Patients with Locally Advanced Rectal Cancer Undergoing Total Mesorectal Excision After Neoadjuvant Chemoradiotherapy

Background

Neoadjuvant chemoradiotherapy (nCRT) followed by surgery of total mesorectal excision (TME) is currently accepted as the standard treatment for locally advanced rectal cancer (LARC). This study aimed to investigate the potential prognostic factors, including the albumin-to-fibrinogen ratio (AFR) for LARC patients.

Methods

We retrospectively recruited LARC patients (cT3-4 and/or cN1-2) who underwent nCRT followed by TME between January 2011 and January 2015. The cut-off value of pretreatment AFR for overall survival (OS) was determined by the receiver operating characteristic (ROC) curve. The potential predictive factors for prognosis in the LARC patients were assessed by the univariate and multivariate Cox’s proportional hazard regression and Kaplan–Meier curve analyses.

Results

AFR was a significant predictor for OS with a cut-off value of 8.65 and an AUC of 0.882 (P<0.001). The pretreatment AFR level was the only independent risk factor for pathologic response to nCRT (HR: 2.44, 95% CI: 1.43–4.17, P=0.003), 5-year OS (HR: 3.31, 95% CI: 1.51–6.77, P=0.005) and disease-free survival (DFS) (HR: 2.73, 95% CI: 1.34–5.47, P=0.007) in LARC patients. A low pretreatment AFR level was significantly associated with a poor 5-year OS and DFS by the Log rank test (P=0.003 and 0.006, respectively).

Conclusion

Pretreatment AFR level was an independent prognostic factor in LARC patients undergoing TME after nCRT.

Prognostic value of the preoperative fibrinogen-to-albumin ratio in pancreatic ductal adenocarcinoma patients undergoing R0 resection

BACKGROUND

Inflammation plays an important role in tumor progression, and growing evidence has confirmed that the fibrinogen-to-albumin ratio (FAR) is an important prognostic factor for overall survival in malignant tumors.

AIM

To investigate the prognostic significance of FAR in patients undergoing radical R0 resection of pancreatic ductal adenocarcinoma (PDAC).

METHODS

We retrospectively analyzed the data of 282 patients with PDAC who underwent radical R0 resection at The Cancer Hospital of the Chinese Academy of Medical Sciences from January 2010 to December 2019. The surv_cutpoint function of the R package survminer via RStudio software (version 1.3.1073, http://www.rstudio.org) was used to determine the optimal cut-off values of biological markers, such as preoperative FAR. The Kaplan-Meier method and log-rank tests were used for univariate survival analysis, and a Cox regression model was used for multivariate survival analysis for PDAC patients who underwent radical R0 resection.

RESULTS

The optimal cut-off value of FAR was 0.08 by the surv_cutpoint function. Higher preoperative FAR was significantly correlated with clinical symptoms (P = 0.001), tumor location (P < 0.001), surgical approaches (P < 0.001), preoperative plasma fibrinogen concentration (P < 0.001), and preoperative plasma albumin level (P < 0.001). Multivariate analysis showed that degree of tumor differentiation (P < 0.001), number of metastatic lymph nodes [hazard ratio (HR): 0.678, 95% confidence interval (CI): 0.509-0.904, P = 0.008], adjuvant therapy (HR: 1.604, 95%CI: 1.214-2.118, P = 0.001), preoperative cancer antigen 19-9 level (HR: 1.740, 95%CI: 1.288-2.352, P < 0.001), and preoperative FAR (HR: 2.258, 95%CI: 1.720-2.963, P < 0.001) were independent risk factors for poor prognosis in patients with PDAC who underwent radical R0 resection.

CONCLUSION

The increase in preoperative FAR was significantly related to poor prognosis in patients undergoing radical R0 resection for PDAC. Preoperative FAR can be used clinically to predict the prognosis of PDAC patients undergoing radical R0 resection.

Endothelial transdifferentiation of human HGC-27 gastric cancer cells in vitro

Malignant tumor cells are able to transdifferentiate into other cell types in various tissues or organs. Recent studies have demonstrated the ability of cancer cells to transdifferentiate into functional endothelial cells (ECs). However, whether human gastric cancer (GC) cells are able to transdifferentiate into other cell types has remained largely elusive. Furthermore, whether HGC-27 cells are able to participate in GC angiogenesis remains to be clarified. In the present study, the HGC-27 cell line grown under hypoxic conditions for 4 days exhibited the typical ‘flagstone’ appearance, which is typical for cultured ECs. HGC-27 cells cultured on Matrigel under hypoxic conditions gradually formed net-like structures. Furthermore, the cultured HGC-27 cells expressed CD31, CD34 and von Willebrand factor, the molecular markers for ECs, under hypoxic conditions. These results indicated that HGC-27 cells, cultured under hypoxic conditions, are able to transdifferentiate into EC-like cells in vitro.

Fibrinogen Alpha Chain Knockout Promotes Tumor Growth and Metastasis through Integrin-AKT Signaling Pathway in Lung Cancer

Fibrinogen is an extracellular matrix protein composed of three polypeptide chains with fibrinogen alpha (FGA), beta (FGB) and gamma (FGG). Although fibrinogen and its related fragments are involved in tumor angiogenesis and metastasis, their functional roles are incompatible. A recent genome-scale screening reveals that loss of FGA affects the acceleration of tumor growth and metastasis of lung cancer, but the mechanism remains elusive. We used CRISPR/Cas9 genome editing to knockout (KO) FGA in human lung adenocarcinoma (LUAD) cell lines A549 and H1299. By colony formation, transwell migration and matrix invasion assays, FGA KO increased cell proliferation, migration, and invasion but decreased the expressions of epithelial-mesenchymal transition marker E-cadherin and cytokeratin 5/8 in A549 and H1299 cells. However, administration of FGA inhibited cell proliferation and migration but induced apoptosis in A549 cells. Of note, FGA KO cells indirectly cocultured by transwells with FGA wild-type cells increased FGA in the culture medium, leading to decreased migration of FGA KO cells. Furthermore, our functional analysis identified a direct interaction of FGA with integrin α5 as well as FGA-integrin signaling that regulated the AKT-mTOR signaling pathway in A549 cells. In addition, we validated that FGA KO increased tumor growth and metastasis through activation of AKT signaling in an A549 xenograft model. IMPLICATIONS: These findings demonstrate that that loss of FGA facilities tumor growth and metastasis through the integrin-AKT signaling pathway in lung cancer.

Identification of angiogenesis-inhibiting peptides from Chan Su

Chan Su is a traditional medicine prepared from toxic secretions from the auricular and skin glands of Chinese toads. Previous studies show that active components in Chan Su can inhibit the proliferation of tumor cells. To study the effect of Chan Su peptides on angiogenesis, fresh Chan Su was collected and its component peptides were isolated by an extraction and precipitation method. A high-performance liquid chromatography (HPLC) fingerprint of the Chan Su component peptides revealed that there were more than 18 peptide component peaks. We demonstrate that Chan Su peptides inhibit angiogenesis in vitro by inhibiting human umbilical vein endothelial cell (HUVEC) proliferation and tube formation in a dose-dependent manner. Western blots indicated that Chan Su peptides inhibited the protein expression of VEGF165 and Ras, leading us to conclude that Chan Su peptide components exert anti-angiogenic effects by suppressing the VEGF165-VEGFR2-Ras signalling pathway. Finally, we identified the partial amino acid sequences of seven Chan Su peptides using the shotgun proteomics method.

Prognostic significance of the ratio of fibrinogen and albumin in human malignancies: a meta-analysis

Background and aim: Serum fibrinogen and albumin are two important factors in systemic inflammation and these two factors are related to tumor progression. This study aimed to comprehensively reveal the prognostic value of the ratio of fibrinogen and albumin in malignant tumors.

Methods: We systematically searched relevant studies in PubMed, Web of Science and Embase up to November 21, 2018. Hazard ratios (HRs) or odds ratio (ORs) for overall survival (OS)/disease-free survival (DFS), as well as relevant clinical data, were collected for analysis; all data analyses were performed by using STATA/SE 14.

Results: Twelve cohort studies were included in this meta-analysis, with a total of 5,088 cases including 9 different kinds of tumors recruited. The pooled results showed that high albumin/fibrinogen ratio (FAR) and low fibrinogen/albumin ratio (AFR) were significantly associated with poor OS (HR=1.50, 95% CI: 1.30–1.70). Subgroup analyses for OS were also performed based on the disease type, detection method, follow-up time and treatment. Similarly, high FAR or low AFR indicated a worse DFS in cancer patients (HR=1.86; 95% CI: 1.41–2.31). In addition, high FAR or low AFR was statistically significant in relation to deeper tumor infiltration (OR=2.81, 95%CI: 1.67–4.72), positive lymph node metastasis (OR=1.57, 95%CI: 1.23–2.02) and distant metastasis (OR=2.30, 95% CI: 1.36–3.89) as well as advanced clinical stage (OR=2.02, 95% CI: 1.17–3.47).

Conclusions: The ratio of fibrinogen and albumin could act as a promising prognostic marker in human malignant tumors. It might assist physicians to select optimal treatments by identifying the current status of the patient. Future multicenter clinical trials are needed to validate its applications.

Histone-lysine N-methyltransferase SETD7 is a potential serum biomarker for colorectal cancer patients

Background

There is an urgent need for the identification of new, clinically useful biomarkers of CRC to enhance diagnostic and prognostic capabilities.

Methods

We performed proteomic profiling on serum samples from paired pre- and post-operative CRC patients, colorectal polyps patients and healthy controls using an approach combining magnetic bead-based weak cation exchange and matrix-assisted laser desorption ionization-time of flight mass spectrometry. We next performed liquid chromatography-electrospray ionization-tandem mass spectrometry to identify the proteins and selected potential biomarker based on bioinformatics analysis of the TCGA and GEO dataset. We examined SETD7 expression in serum and tissue samples by ELISA and immunohistochemistry respectively and explored the biological function of SETD7 in vitro.

Findings

85 differentially expressed peptides were identified. Five peptides showing the most significant changes in abundance across paired pre- and post-operation CRC patients, colorectal polyps patients and healthy controls were identified as peptide regions of FGA, MUC5AC and SETD7. Bioinformatics analysis suggested that the up-regulation of SETD7 in CRC is relatively specific. Validation studies showed that SETD7 expression increased from healthy controls to those with colorectal polyps and finally CRC patients, and decreased after surgery. The sensitivity and specificity of SETD7 were 92.17% and 81.08%, with a high diagnostic value (AUC = 0.9477). In addition, SETD7 expression was significantly correlated with tumor stage and microsatellite instability. Knockdown of SETD7 inhibited cancer cell proliferation, induced G1/S cell cycle arrest and increased apoptosis.

Interpretation

Our data indicate that SETD7 could serve as a potential diagnostic and prognostic biomarker for CRC.

Preoperative plasma fibrinogen is associated with poor prognosis in esophageal carcinoma: a meta-analysis

PURPOSE

The aim of this meta-analysis was to investigate preoperative plasma fibrinogen (PPF) as a prognostic marker in esophageal carcinoma (EC) by meta-analysis.

METHODS

Relevant studies were sought in the databases including Pubmed, Web of Science, Cochrane library, and Wanfang databases up to Oct 10th, 2017. Hazard ratios (HRs) with corresponding 95% confidence intervals (CIs) were used as effective value, and pooled HRs were synthesized by STATA 14.0 to assess the prognostic impact of PPF on EC patients.

RESULTS

A total of 8 studies with 2827 patients were collected in this meta-analysis. Our results revealed that high PPF was significantly associated with poor OS (HR = 1.90, 95% CI 1.56-2.33, P = 0.000; HR = 1.76, 95% CI 1.28-2.42, P = 0.000) and poor DFS (HR = 1.91, 95% CI 1.50-2.43, P = 0.000; HR = 1.51, 95% CI 1.16-1.97, P = 0.000) in EC patients from univariate and multivariate analysis results, respectively, which suggested that EC patients with high PPF will suffer from high postoperative mortality and recurrence rate.

CONCLUSION

High PPF was significantly associated with poor OS and DFS in EC patients. Fibrinogen can serve as a prognostic marker and even a future targeting molecule during the treatment of EC patients.

Transdifferentiation of human MNNG/HOS osteosarcoma cells into vascular endothelial cells in vitro and in vivo

The transdifferentiation of cancer cells into other types of cells in several types of tissues or organs has been studied. However, whether human osteosarcoma MNNG/HOS cells can transdifferentiate into other types of cells has seldom been reported. Meanwhile, the mechanism of tumor angiogenesis is still disputed, and whether MNNG/HOS cells participate in angiogenesis in osteosarcoma remains unknown. In the present study, the investigation was divided into two parts: in vitro and in vivo. In vitro, we cultivated MNNG/HOS cells under hypoxic conditions for 4 days and found that they typically showed a characteristic 'flagstone' appearance as cultured vascular endothelial cells (VECs). MNNG/HOS cells that were cultivated on Matrigel under hypoxic conditions gradually formed tubular-like structures. Furthermore, when cultured under hypoxic conditions for 4 days, MNNG/HOS cells also transcribed and expressed several molecular markers of VECs (CD31, CD34 and vWF). In vivo, MNNG/HOS cells (1x106 cells) were cultivated under hypoxic conditions and subcutaneously injected into nude mice; the mice were sacrificed 49 days after inoculation. Immunohistochemical staining with anti-human CD31 antibody showed evidence of tumor angiogenesis in human osteosarcoma MNNG/HOS cells. The results demonstrated that MNNG/HOS cells can transdifferentiate into vascular endothelial cell-like cells in vitro and in vivo.

Preoperative peripheral plasma fibrinogen level is an independent prognostic marker in penile cancer

BACKGROUND AND AIM

High levels of peripheral plasma fibrinogen have recently been revealed that related to poor clinical prognosis in various types of malignant tumors. The purpose of this research was to identify the prognostic significance of the preoperative peripheral serum fibrinogen level in patients with penile cell carcinoma.

METHODS

This retrospective research included 72 penile cancer patients with date about their serum fibrinogen value before surgery who undergone either partial or radical penectomy at The 2nd Hospital of Tianjin Medical University between January 2002 to January 2012. They had a mean follow-up of 30.8 months. To determine the factors that were significant in predicting a patient's prognosis, univariate and multivariate analyses were performed according to the Cox proportional hazards regression model.

RESULTS

The 5-year cancer specific survival (CSS) rate was 62.4% of patients with preoperative fibrinogen levels below 340 mg/dl and 41.9% for those with higher levels (p = 0.001). Multivariate analysis revealed that the pathological T stage (p < 0.001), tumor grade (p = 0.036), postoperative chemotherapy (p = 0.041), nodal metastasis(p < 0.001), pathological type (p < 0.001) and fibrinogen (p = 0.023) were independent prognostic factors for survival. Patients with low fibrinogen level (<340mg/dl) had significantly longer CSS and the different survival rate were defined using the log-rank test.

CONCLUSIONS

The high preoperative peripheral serum fibrinogen level was related to poor survival in penile cancer patients. Fibrinogen may serve as a powerful predictor of CSS in penile cancer patients.

Peptides derived from plasma proteins released by bothropasin, a metalloprotease present in the Bothrops jararaca venom

Viperid snake venoms contain proteases that affect hemostasis by degrading important proteins such as those that participate in the coagulation cascade. The Bothrops jararaca venom presents as its main components metallo and serine proteases, which comprise around 65% of the venom composition. Bothropasin is a hemorrhagic metalloprotease from the B. jararaca venom which causes disruption of the basement membrane of the vascular endothelium, resulting in bleeding. Although the bothropasin ability to degrade plasmatic and extracellular matrix proteins in vitro has been described, the primary sequence of the released peptides is unknown. This research study presents the peptide identification from both fibrinogen and fibronectin, generated by bothropasin proteolytic activity. Among the fibrinogen derived peptides identified by mass spectrometry, analogous of endogenous products like the fibrinopeptides A and B were found, as well as other sequences described in the literature with vasoactive or antiangiogenic properties. A series of peptides derived from fibronectin by the action of bothropasin were described, and for most of them no biological activity has been described. However, exceptionally a peptide that is known as a bond site for B cells was found. This study indicates that, beyond to the degradation of human proteins, bothropasin can generate bioactive peptides, which may participate in the envenoming process by Bothrops snakes. Also important, the knowledge of the formed peptides, based on the cleavage sites of the hydrolyzed proteins, provided the opportunity to study the primary specificity of bothropasin.

Proteome analysis of sheep B lymphocytes in the course of bovine leukemia virus-induced leukemia

Presented are the results of a study of the expression pattern of different proteins in the course of bovine leukemia virus-induced leukemia in experimental sheep and I discuss how the obtained data may be useful in gaining a better understanding of the pathogenesis of the disease, diagnosis, and for the selection of possible therapeutic targets. In cattle, the disease is characterized by life-long persistent lymphocytosis leading to leukemia/lymphoma in about 5% of infected animals. In sheep, as opposed to cattle, the course of the disease is always fatal and clinical symptoms usually occur within a three-year period after infection. For this reason, sheep are an excellent experimental model of retrovirus-induced leukemia. This model can be useful for human pathology, as bovine leukemia virus is closely related to human T-lymphotropic virus type 1. The data presented here provide novel insights into the molecular mechanisms of the bovine leukemia virus-induced tumorigenic process and indicate the potential marker proteins both for monitoring progression of the disease and as possible targets of pharmacological intervention. A study of the proteome of B lymphocytes from four leukemic sheep revealed 11 proteins with altered expression. Among them, cytoskeleton and intermediate filament proteins were the most abundant, although proteins belonging to the other functional groups, i.e. enzymes, regulatory proteins, and transcription factors, were also present. It was found that trypsin inhibitor, platelet factor 4, thrombospondin 1, vasodilator-stimulated phosphoprotein, fibrinogen alpha chain, zyxin, filamin-A, and vitamin D-binding protein were downregulated, whereas cleavage and polyadenylation specificity factor subunit 5, non-POU domain-containing octamer-binding protein and small glutamine-rich tetratricopeptide repeat-containing protein alpha were upregulated. Discussed are the possible mechanisms of their altered expression and its significance in the bovine leukemia virus-induced leukemogenic process. Impact statement The submitted manuscript provides new data on the molecular mechanisms of BLV-induced tumorigenic process indicating the potential marker proteins both for monitoring the progression of the disease and as possible targets of pharmacological intervention. This is to my knowledge the first study of the proteome of the transformed lymphocytes in the course of bovine leukemia virus-induced leukemia in susceptible animals. BLV can be considered as useful model for related human pathogen - HTLV-1, another member of the deltaretrovirus genus evolutionary closely related to BLV. Information gathered in this study can be useful to speculate on possible shared mechanisms of deltaretrovirus-induced carcinogenesis.

Fibrinogen-derived fibrinostatin inhibits tumor growth through anti-angiogenesis

Angiogenesis is a prerequisite of tumor growth and metastasis and, thus, anti‐angiogenesis treatment has become an important part of cancer therapy. A 15‐amino acid peptide of the fibrinogen α chain, fibrinostatin, was previously found in serum samples of gastric cancer patients. Herein we demonstrated that fibrinostatin has anti‐angiogenesis activity in several angiogenesis models and it reduces tumor growth in mouse xenografts and allografts. Increased tumor necrosis and reduced microvessel density in tumors were observed in mouse xenograft models. Fibrinostatin inhibited proliferation and induced apoptosis in HUVEC, but not in cancer cells. In addition, fibrinostatin specifically entered HUVEC. Fibrinostatin also prevented migration, adhesion and tubule formation of HUVEC in vitro. A single‐dose acute toxicity testing and a repeated‐dose chronic toxicity study in the mouse, rat and monkey indicated that fibrinostatin had a wide margin of safety. Taken together, fibrinostatin shows promise as a potential anti‐angiogenesis therapeutic agent.