Tumor Angiogenesis Progression Research Articles

Epigenetic regulation of angiogenesis in tumor progression.

Epigenetic is the study of those alterations regulating gene expression without altering DNA sequence and inherited by transmission through cell division. DNA hypomethylation, hypermethylation of tumor suppressor genes, aberrant histone modifications and/or specific microRNAs expression profiles contribute to tumor initiation and progression. In this review, we will discuss the role of epigenetic changes in the regulation of tumor angiogenesis.

Immunohistochemical evaluation of CD31 and D2-40, expression in oral squamous cell carci-noma

Background: The present study was carried out to evaluate the relation between angiogenesis, and tumor stage of oral squamous cell carcinoma (OSCC).Materials and methods: Thirty formalin-fixed paraffin embedded blocks were used, ten of them were previously diagnosed as well differentiated OSCC, ten moderately differentiated OSCC and ten poorly differentiated OSCC. To determine the expression of CD31 and D2-40 proteins, streptavidin-biotin immunoperoxidase staining technique was used. The areas with the most vascular density (hot spots) were determined. The stained vessels were counted independently in intratumoral and peritumoral stroma. Results: CD 31 protein showed positive expression in the peritumoral and intratumoral blood vessels subjacent to the malignant invading nests. D2-40 expression was positive in lymphatic vessel in the peritumoral and intratumoral stroma subjacent to the invading nests. The highest mean values of both CD31 and D2-40 proteins expression were recorded in poor differentiated OSSC followed by moderate differentiated OSSC then well differentiated OSSC. There was statistically significant difference found between the three studied groups regarding CD31 and D2-40 levels. Also there was statistically significant positive correlation found between CD31 level and D2-40 level.Conclusion: CD31 and D2-40 are related to stage of OSCC and are consistent with angiogenesis in tumor progression.

Prostate-Specific Membrane Antigen (PSMA) Promotes Angiogenesis of Glioblastoma Through Interacting With ITGB4 and Regulating NF-κB Signaling Pathway.

BackgroundGlioblastoma multiforme (GBM) is the most common primary malignant tumor in the central nervous system (CNS), causing the extremely poor prognosis. Combining the role of angiogenesis in tumor progression and the role of prostate-specific membrane antigen (PSMA) in angiogenesis, this study aims to explore the functions of PSMA in GBM.MethodsClinical GBM specimens were collected from 60 patients who accepted surgical treatment in Fudan University Shanghai Cancer Center between January 2018 and June 2019. Immunohistochemical staining was used to detect PSMA and CD31 expression in GBM tissues. Prognostic significance of PSMA was evaluated by bioinformatics. Human umbilical vein endothelial cells (HUVECs) transfected with PSMA overexpression plasmids or cultured with conditioned medium collected based on GBM cells, were used for CCK8, Transwell and tube formation assays. High-throughput sequencing and immunoprecipitation were used to explore the underlying mechanism. Furthermore, the in vivo experiment had been also conducted.ResultsWe demonstrated that PSMA was abundantly expressed in endothelium of vessels of GBM tissues but not in vessels of normal tissues, which was significantly correlated with poor prognosis. Overexpression of PSMA could promotes proliferation, invasion and tube formation ability of human umbilical vein endothelial cells (HUVECs). Moreover, U87 or U251 conditioned medium could upregulated PSMA expression and induce similar effects on phenotypes of HUVECs, all of which could be partially attenuated by 2-PMPA treatment. The mechanistic study revealed that PSMA might promote angiogenesis of GBM through interacting with Integrin β4 (ITGB4) and activating NF-κB signaling pathway. The in vivo growth of GBM could be alleviated by the treatment of 2-PMPA.ConclusionThis study identified PSMA as a critical regulator in angiogenesis and progression of GBM, which might be a promising therapeutic target for GBM treatment.

Combination of Serum Amyloid A and C-Reactive Protein Exhibit Synergistic Effect in Angiogenesis by Inducing Inflammation and Vascular Network

The role of angiogenesis in tumor progression has been recognized as one of the hallmarks of cancer, but the mechanism of its action remains unclear. Inflammatory markers serum amyloid A (SAA) and C-reactive protein (CRP) are proposed to play causal roles in the development of various disorders, including malignancies. Previously, we identified the complex of CRP and SAA (CRP-SAA) with diagnostic and prognostic value better than either one of them in the serum of lung cancer patients. In this study, we further explored the stimulation function of CRP-SAA on angiogenesis and inflammation. To explore possible mechanisms, microarray datasets were downloaded from the Gene Expression Omnibus (GEO) database and multi-bioinformatics analysis revealed that THP-1 and human umbilical vein endothelial cells (HUVECs) responded to SAA stimulation with upregulation of two pro-angiogenic cytokines in common, i.e., C-X-C motif ligand 6 (CXCL6) and CXCL8, which were validated by subsequent experiments in vitro. CRP had weak effects as a single stimulus, but it can efficiently potentiate the SAA induction of cytokines, which was stronger than the sum of the both (P < 0.001). The synergistical effect of the combination of CRP and SAA enhanced HUVECs transwell and constricted morphology by upregulating the pro-angiogenic genes. These results indicated that the binding of CRP and SAA acted synergistically in pro-angiogenesis by increasing inflammation and inducing vascular network.

Role of PFKFB3 and CD163 in Oral Squamous Cell Carcinoma Angiogenesis.

6-phosphofructo-2-kinase/fructose-2, 6-biphosphatase 3 (PFKFB3), an enzyme producing fructose 2, 6-bisphosphate (F-2, 6-BP), serves as a switch to activate phosphofructokinase-1, and is a critical enzyme for endothelial glycolysis, mediating circadian control of carcinogenesis. Also, tumor-associated macrophages (TAMs) play an important role in the progression and prognosis of numerous cancers. However, the role and clinical significance of PFKFB3 and TAMs in oral squamous cell carcinoma (OSCC) have not been elucidated. The present study was designed to investigate the correlation between PFKFB3 expression, CD163+ TAMs infiltration and tumor angiogenesis in OSCC by tissue microarray. Tissue microarrays containing 117 OSCC specimens and 56 matched paracarcinoma tissues were studied by immunohistochemistry. The expression levels of PFKFB3, CD163 and CD31 were significantly increased in OSCC specimens as compared with normal oral mucosa (P<0.05), and PFKFB was signifcantly correlated with tumor differentiation and tumor size (P<0.05), and CD163 was significantly correlated with areca nut chewing habit among OSCC tissues (P<0.05). Furthermore, Pearson's correlation analysis revealed that PFKFB3 was signifcantly correlated with both CD163 and CD31 (P<0.05), meanwhile CD163 was signifcantly correlated with CD31 (P<0.001), suggesting PFKFB3 may promote angiogenesis in tumor progression and metastases by regulating CD163+ TAMs infiltration in OSCC.

Regulation of Blood and Lymphatic Vessels by Immune Cells in Tumors and Metastasis.

Research over the last decades has provided strong evidence for the pivotal role of the tumor-associated blood and lymphatic vasculature in supporting immunoevasion and in subverting T cell-mediated immunosurveillance. Conversely, tumor blood and lymphatic vessel growth is in part regulated by the immune system, with infiltrating innate as well as adaptive immune cells providing both immunosuppressive and various angiogenic signals. Thus, tumor angiogenesis and escape of immunosurveillance are two cancer hallmarks that are tightly linked and interregulated by cell constituents from compartments secreting both chemokines and cytokines. In this review, we discuss the implication and regulation of innate and adaptive immune cells in regulating blood and lymphatic angiogenesis in tumor progression and metastases. Moreover, we also highlight novel therapeutic approaches that target the tumor vasculature as well as the immune compartment to sustain and improve therapeutic efficacy in cancer.

Deregulation of VEGFR-2 and PDGFR Expression and Microvascular Density in a Triple-Negative Model of Canine Malignant Mammary Tumors with Lymph Node or Lung Metastasis

Canine mammary tumors (CMT) represent the most common cancer in noncastrated female dogs. Interestingly, triple-negative tumors are the most common molecular subtype in female dogs. In this study, we proposed to evaluate the expression of vascular endothelial growth factor receptor 2 (VEGFR-2), Platelet-derived growth factor receptor (PDGFR), and microvascular density (MVD) in a group of metastatic and nonmetastatic triple-negative CMT and compare the expression based on clinical parameters. Twenty-six female dogs with triple-negative mammary tumors were divided into three groups: nonmetastatic tumors (NMT) (n = 11), tumors with lymph node metastasis (LNM) (n = 10), and tumors with lung metastasis (LM) (n = 5). We observed increased VEGFR-2 expression in LNM compared with NMT and a positive correlation between tumor grade and VEGFR-2 expression. A positive correlation was noted between VEGFR-2 and PDGFR expression. Regarding microvascular density (MVD), we identified a higher number of vessels in primary tumors with lymph node metastasis and lung metastasis compared with tumors with no metastasis. The primary tumors with lung metastasis exhibited an increased MVD compared with carcinoma with lymph node metastasis. Overall, our results suggest a deregulation of VEGFR-2 and PDGFR and high MVD in metastatic tumors, indicating a role for angiogenesis in tumor progression.

VEGF Upregulation in Viral Infections and Its Possible Therapeutic Implications.

Several viruses are recognized as the direct or indirect causative agents of human tumors and other severe human diseases. Vascular endothelial growth factor (VEGF) is identified as a principal proangiogenic factor that enhances the production of new blood vessels from existing vascular network. Therefore, oncogenic viruses such as Kaposi’s sarcoma herpesvirus (KSHV) and Epstein-Barr virus (EBV) and non-oncogenic viruses such as herpes simplex virus (HSV-1) and dengue virus, which lack their own angiogenic factors, rely on the recruitment of cellular genes for angiogenesis in tumor progression or disease pathogenesis. This review summarizes how human viruses exploit the cellular signaling machinery to upregulate the expression of VEGF and benefit from its physiological functions for their own pathogenesis. Understanding the interplay between viruses and VEGF upregulation will pave the way to design targeted and effective therapeutic approaches for viral oncogenesis and severe diseases.

In vivo and In vitro effects of ethanolic extract of Trigonella foenum-graecum L. seeds on proliferation, angiogenesis and tube formation of endothelial cells.

The role of angiogenesis in tumor progression and metastasis formation has been well recognized. Recent studies have reported that Trigonella foenum-graecum L. (fenugreek) seed extracts have potential anticancer properties. The current study was planned to investigate the anti-angiogenic activity of hydroalcoholic extract of fenugreek (HAEF) in vitro and in vivo. Effect of HAEF (50-3000 µg/mL) and thalidomide (200-3000 µmol/L), as a positive control, on the viability of human umbilical vein endothelial cells (HUVECs) and 3T3 fibroblast cells was assessed by thiazolyl blue tetrazolium bromide (MTT) assay. Effect of HAEF on vessel-like tube formation by HUVECs was examined in the matrigel-based assay. Furthermore, the chick chorioallantoic membrane (CAM) was used as in vivo model to study the anti-angiogenic effect of HAEF. HAEF, similar to thalidomide, significantly inhibited the viability of HUVECs and 3T3 cells dose-dependently after 24 h. Moreover, both HAEF and thalidomide significantly reduced tube formation by HUVECs in cell culture condition. In CAM model, HAEF and thalidomide caused a significant decline in the number of neovascular points and in the amount of grades 1 and 2 vessels. These findings revealed that fenugreek has cytotoxic and anti-angiogenic effects in vitro and in vivo. Therefore, this medicinal plant can be subjected to further investigations as antitumor agents.

Immunohistochemical expression of pericytes and myofibroblasts in the extracellular matrix of oral actinic cheilitis and squamous cell carcinoma: a comparative study

OBJECTIVE: The aim of the present study is to conduct a comparative analysis of oral actinic cheilitis and squamous cell carcinomas by immunohistochemical analysis.METHODS: This cross-sectional study utilizes a convenience sample obtained from the archives of an oral pathology laboratory from a higher education institution. Tissue sections from patients diagnosed with actinic cheilitis and carcinoma were immunohistochemically analyzed using monoclonal antibodies specific for smooth muscle alpha actin (SMA) and neuron-glial antigen 2 (NG2). Individual cells that stained positive for these proteins were counted in specific fields by means of histomorphometry.RESULTS: Subsequent statistical analysis revealed a higher number of NG2-positive when compared with SMA-positive cells in both lesion types (p = 0.005) and these cells were located adjacent to blood vessels. The differences between normal oral mucosa, severe dysplasia, and carcinoma specimens were statistically significant (p = 0.009; p = 0.006).CONCLUSION: These data strongly suggest that increased expression of NG2- and SMA-positive cells is associated with formation of blood capillaries, highlighting the importance of angiogenesis in tumor progression.

Localization of VEGF to Vascular ECM Is an Important Aspect of Tumor Angiogenesis.

Our research has identified several examples in which reduced VEGF-A binding to deficient vascular extracellular matrix leads to deficits in tumor vascularization and tumor growth: (1) germline ablation of collagen VI in the stroma of intracranial B16F10 melanomas; (2) knockdown of the Tks5 scaffolding protein in MDA-MB-231 mammary tumor cells; (3) germline ablation of NG2 proteoglycan in the stroma of MMTV-PyMT mammary tumors; and (4) myeloid-specific ablation of NG2 in the stroma of intracranial B16F10 melanomas. Tumor hypoxia is increased in each of the four types of experimental mice, accompanied by increases in total VEGF-A. However, while VEGF-A is highly associated with tumor blood vessels in control mice, it is much more diffusely distributed in tumors in all four sets of experimental mice, likely due to reduced extent of the vascular extracellular matrix. In parallel to lost VEGF-A localization, tumor vessels in each case have smaller diameters and are leakier than tumor vessels in control mice. Tumor growth is decreased as a result of this poor vascular function. The fact that the observed vascular changes occur in the absence of alterations in vascular density suggests that examination of vessel structure and function is more useful than vascular density for understanding the importance of angiogenesis in tumor progression.

Impact of vascular endothelial growth factor (VEGF) and hypoxia-inductible factor-1 alpha (HIF-1) expression on the prognosis of locally advanced cervical carcinoma (LACC) treated with radiochemotherapy.

e17023 Background: Combination of radiotherapy plus platinum-based chemotherapy (RT-CT) is considered the standard treatment in LACC. The risk of recurrence after local treatment is around 50-70%. The role of angiogenesis in tumor progression has been shown in large series. The aim of this study was to determinate the impact of the expression of VEGF and HIF-1 on disease-free survival (DFS) and overall survival (OS) in patients with LACC receiving RT-CT. Methods: Expression of VEGF and HIF–1 was assessed by an immunohistochemistry (IHC) assay in 115 cases. Inmunostainning was considered negative (&lt; 10% of cells), slightly positive (&lt; 25%), moderate (26%-50%) and strongly positive (&gt; 50%). A univariate analysis was carried out for each variable using the log-rank test. Subsequently, a multivariate analysis was performed employing Cox’s proportional hazards model. Results: 115 patients (p) with LACC were included and received RT-CT between January/2003 and December/2012. IHC revealed absence of expression of VEGF in 12 (10,4%) cases, slightly positive in 34 (29,6%), moderate in 30 (26,1%) and strongly positive in 39 (33,9%). The expression of HIF-1 was negative in 63 (54,8%) cases and positive (weak or moderate) in 52 (45,2%). 76p (66,1%) showed a complete clinical response (CR), 26p (22,6%) partial response and 13p (11,3%) stable disease or progression. The median follow–up was 35 months (1-140). 56p (48,7%) relapsed. Univariate analysis indicate that ECOG &gt; 1, tumor size ≥ 4,5 cm, FIGO stage III-IVA, lymph nodes positive, non CR, CA125 post-treatment ≥ 35 U/mL, hemoglobin levels &lt;11 mg/dl (basal, nadir and post-treatment), strong expression VEGF and positive expression of HIF – 1 were all associated with a significant lower OS and DFS. In multivariate analysis strong expression of VEGF remained statistically significant, as tumor size, non CR and hemoglobin level post-treatment &lt; 11g/dL. Conclusions: IHC-assessed strong expression of VEGF was independent prognostic factor of shorter OS and DFS in patients with LACC treated with RT-CT. IHC determination of VEGF could be useful in clinical practice.

Association of Macrophages With Angiogenesis in Oral Epithelial Dysplasia, Oral Verrucous Carcinoma, and Oral Squamous Cell Carcinoma: An Immunohistochemical Study.

The present study aimed to elucidate the role of tumor-associated macrophages (TAMs) and angiogenesis in tumor progression by assessing their immunohistochemical expression in oral epithelial dysplasia (OED), oral verrucous carcinoma (OVC), and oral squamous cell carcinoma (OSCC). About 20 histopathologically confirmed cases of OED, OVC, and OSCC each and 10 cases of normal oral mucosa taken as controls were stained immunohistochemically using CD68 and CD31 antibodies. The average TAM count and the microvessel density (MVD) were calculated for each group and expressed as mean±SD and compared using the Mann-Whitney U Test. Pearson correlation was applied to assess the correlation between TAM and MVD in different groups. The CD68 count was found to be significantly higher in all the groups as compared with controls, with the highest counts in OSCC, followed by OED and OVC. MVD was significantly higher in all the test groups as compared with controls. The increase in MVD was highly significant in OSCC as compared with OVC, and in OVC as compared with OED. No association could be determined between TAM and MVD. There does not seem to be any direct influence of macrophages on angiogenesis in the microenvironment of OED, OVC, and OSCC.

KSHV-Mediated Angiogenesis in Tumor Progression.

Human herpesvirus 8 (HHV-8), also known as Kaposi’s sarcoma-associated herpesvirus (KSHV), is a malignant human oncovirus belonging to the gamma herpesvirus family. HHV-8 is closely linked to the pathogenesis of Kaposi’s sarcoma (KS) and two other B-cell lymphoproliferative diseases: primary effusion lymphoma (PEL) and a plasmablastic variant of multicentric Castleman’s disease (MCD). KS is an invasive tumor of endothelial cells most commonly found in untreated HIV-AIDS or immuno-compromised individuals. KS tumors are highly vascularized and have abnormal, excessive neo-angiogenesis, inflammation, and proliferation of infected endothelial cells. KSHV directly induces angiogenesis in an autocrine and paracrine fashion through a complex interplay of various viral and cellular pro-angiogenic and inflammatory factors. KS is believed to originate due to a combination of KSHV’s efficient strategies for evading host immune systems and several pro-angiogenic and pro-inflammatory stimuli. In addition, KSHV infection of endothelial cells produces a wide array of viral oncoproteins with transforming capabilities that regulate multiple host-signaling pathways involved in the activation of angiogenesis. It is likely that the cellular-signaling pathways of angiogenesis and lymph-angiogenesis modulate the rate of tumorigenesis induction by KSHV. This review summarizes the current knowledge on regulating KSHV-mediated angiogenesis by integrating the findings reported thus far on the roles of host and viral genes in oncogenesis, recent developments in cell-culture/animal-model systems, and various anti-angiogenic therapies for treating KSHV-related lymphoproliferative disorders.

The vascular delta-like ligand-4 (DLL4)-Notch4 signaling correlates with angiogenesis in primary glioblastoma: an immunohistochemical study.

Delta-like ligand-4 (DLL4)-Notch signaling is known to play a pivotal role in the regulation of tumor angiogenesis. We had previously found that DLL4 was overexpressed, while Notch1 receptor, which binds to DLL4 during angiogenesis, was absent in the majority of human primary glioblastomas. Thus, DLL4-Notch signaling pathway in the regulation of tumor angiogenesis in primary glioblastoma remains unknown. Tumor tissues from 70 patients with primary glioblastoma were analyzed by immunohistochemistry for expression of components of DLL4-Notch signaling, vascular endothelial growth factor (VEGF), and microvessel density (MVD). Immunohistochemistry results showed that the positive staining of DLL4 and Notch4 was primarily distributed in tumor vascular endothelial cells but rarely detected in tumor cells. However, VEGF, hairy/enhancer of split-1 (HES1; a target gene of Notch signaling), and Notch1-3 expression was seen in both tumor vascular endothelial cells and tumor cells. Univariate analysis showed that the expression levels of VEGF and DLL4, HES1, and Notch4 in tumor endothelial cells were significantly associated with MVD in primary glioblastoma (P < 0.001). Binary logistic regression analysis showed that high expression levels of DLL4, HES1, and Notch4 in tumor endothelial cells were associated with a decrease of MVD in primary glioblastoma, while MVD increased with elevated VEGF expression in contrast. In addition, DLL4, Notch4, and HES1 expression were positively correlated in tumor vascular endothelial cells (P < 0.05). We conclude that the vascular DLL4-Notch4 signaling and VEGF signaling complementing each other plays an important role in the progression of tumor angiogenesis in primary glioblastoma. Graphical abstract A, positive staining of DLL4 in human kidney; B, positive staining of VEGF in human breast cancer; C, positive staining of CD34 in human lung cancer; D, positive staining of HES1 in human breast cancer; E-H, positive staining of Notch1-4: E-F in human lung cancer; G-H in human kidney.

Comparação da imunoexpressão de VEGF, TGF-β e MMP-9 em ameloblastoma e tumor odontogênico adenomatóide

Purpose: Studies on odontogenic tumors have identified various molecular dysfunctions involved on their development, and some mechanisms such as angiogenesis and matrix modulation, are useful means of investigating the differences in biologic behavior of these tumors. Some important markers to identify tumor aggressiveness by immunohistochemistry are VEGF, TGF-β and MMP-9 proteins. This study aimed to compare the immunohistochemical expression of VEGF, TGF-β, and MMP-9 in ameloblastoma and adenomatoid odontogenic tumor (AOT). Methods: Immunoexpression of VEGF, TGF-β, and MMP-9 was studied in 15 solid ameloblastomas, and 15 AOTs. A semi-quantitative analysis of the immunostained cells was performed, and the statistical analysis was made using the Mann-Whitney nonparametric and Spearman correlation test, with significance level at .05 (P .05). Conclusion: The results suggest the involvement of angiogenesis in tumor progression of ameloblastomas, and the inductive effect of stromal cells in AOT, hence justifying its lower growth potential.

Complement and macrophage crosstalk during process of angiogenesis in tumor progression.

The complement system, which contains some of the most potent pro-inflammatory mediators in the tissue including the anaphylatoxins C3a and C5a are the vital parts of innate immunity. Complement activation seems to play a more critical role in tumor development, but little attention has been given to the angiogenic balance of the activated complement mediators and macrophage polarization during tumor progression. The tumor growth mainly supported by the infiltration of M2- tumor-associated macrophages, and high levels of C3a and C5a, whereas M1-macrophages contribute to immune-mediated tumor suppression. Macrophages express a cognate receptors for both C3a and C5a on their cell surface, and specific binding of C3a and C5a affects the functional modulation and angiogenic properties. Activation of complement mediators induce angiogenesis, favors an immunosuppressive microenvironment, and activate cancer-associated signaling pathways to assist chronic inflammation. In this review manuscript, we highlighted the specific roles of complement activation and macrophage polarization during uncontrolled angiogenesis in tumor progression, and therefore blocking of complement mediators would be an alternative therapeutic option for treating cancer.

Abstract 1785: MET/VEGFR dual inhibition and prominent safety profile of TAS-115 are favorable for the combination with chemotherapeutic drugs

Abstract MET is known as a proto-oncogene, which involves in growth, migration, metastasis and angiogenesis in tumor progression. Recently, it is reported that MET also functions as chemo and EGFR-TKI resistant factor in cancer cells. Particularly, HGF/MET signal seemed to reduce the potency of conventional chemotherapeutic drugs in clinical. Meanwhile, VEGF/VEGFR signal plays an important role in angiogenesis in tumor growth, and is essential for the survival signal of endothelial cells(ECs) to protect from the damage by chemotherapeutic drugs. Some VEGFR inhibitors have already been approved for the treatment of several carcinomas with monotherapy. Many clinical combination trials with VEGFR inhibitor and chemotherapeutic agents have been tried, but its therapeutic benefit are restricted. It is highly desire for improving therapeutic benefit by combination therapy with VEGFR inhibitor and standard chemotherapy. TAS-115, a novel oral MET/VEGFR dual inhibitor, demonstrated not only potent efficacy but also prominent safety profiles achieved by improvement of PK profile and cellular selectivity. Potent MET/VEGFR dual inhibition provides significant anti-tumor effect from lower dose for TAS-115. On the one hand, the improvement of PK profile and cell selectivity led to better tolerability. As a result, therapeutic window (MTD/ED50) of TAS-115 became wider than that of the pre-existing VEGFR or MET/VEGFR inhibitors. These profiles give TAS-115 the long-term dosing at full effective dose without severe toxicity. Moreover, in vitro study, HGF completely suppressed the induction of apoptosis by 5-FU or Paclitaxel in cancer cells expressed MET. Meanwhile, VEGF abolished the cytotoxic effect by these chemotherapeutic drugs against ECs. It was suggested that harmonization of both HGF and VEGF in tumor greatly contributed to the resistance against conventional chemotherapeutic drugs. The MET/VEGFR dual inhibition by TAS-115 improves the sensitivity of chemotherapeutic drugs for both cancer cells and ECs via suppression of function as chemo-resistance factor by MET and VEGFR. In fact, the combination therapies with TAS-115 and conventional chemotherapeutic drugs caused tumor regression or potent growth inhibition without sever body weight loss in several xenograft models. Notably, TAS-115 markedly enhanced anti-tumor effect of Paclitaxel, and brought tumor shrinkage of approximately 80% in the combination. More important feature is that TAS-115 has disturbed rapid tumor re-growth following Paclitaxel treatment and the higher safety profiles of TAS-115 permits combination therapy with chemotherapeutic drugs in chronic treatment. It is expected TAS-115 demonstrates prominent therapeutic benefit in combination with chemotherapy based on the synergistic action of the potent MET/VEGFR dual inhibition and higher safety profiles. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1785. doi:1538-7445.AM2012-1785

Tissue Factor (TF) Expression and Angiogenesis in Tumor Progression and Inhibition of Tumor Growth by Anti-TF Antibodies in Human Tissue Factor Knock-In Mice

Background: Tissue factor (TF) serves as the primary initiator of the extrinsic pathway of blood coagulation and mediates signaling via the protease activated receptor-2 (PAR2). TF is over-expressed in several tumor types and may facilitate tumor progression and angiogenesis. To test the hypothesis that inhibition of TF may have an anti-tumor effect, we induced pulmonary adenomas (PA) in human TF knock in (huTF-KI) mice with urethane and studied the relationship between expression of TF and mutations in K-ras with tumor progression and the effect of a monoclonal anti-TF antibody on growth of a transplantable lymphoma. Methods: huTF-KI mice received 10 weekly intraperitoneal (i.p.) injections of urethane and samples of lung were collected at six week intervals between weeks 10 and 28. Expression of TF and von Willibrand factor (vWF) in PA were studied by immunohistochemistry (IHC) and mutations in K-ras were studied by laser capture microdissection and polymerase chain reaction (LCM-PCR). Results: IHC showed that expression of TF and vWF increased as pulmonary epithelial hyperplasias and PA progressed. Dual staining TF and vWF showed that areas of high expression of TF correlated with the tumor vasculature and LCM-PCR showed that mutation of K-ras correlated with expression of TF and the angiogenic switch in PA. Finally, an anti-huTF monoclonal antibody slowed the growth of transplantable urethane-induced lymphomas. Conclusion: Taken together, these data suggest that expression of TF plays an important role in tumor progression and the angiogenic switch. These data also suggest that anti-TF antibodies may be a viable tumor immunotherapy

TRPV4 mediates tumor-derived endothelial cell migration via arachidonic acid-activated actin remodeling

Changes in intracellular calcium [Ca(2+)](i) levels control critical cytosolic and nuclear events that are involved in the initiation and progression of tumor angiogenesis in endothelial cells (ECs). Therefore, the mechanism(s) involved in agonist-induced Ca(2+)(i) signaling is a potentially important molecular target for controlling angiogenesis and tumor growth. Several studies have shown that blood vessels in tumors differ from normal vessels in their morphology, blood flow and permeability. We had previously reported a key role for arachidonic acid (AA)-mediated Ca(2+) entry in the initial stages of tumor angiogenesis in vitro. In this study we assessed the mechanism involved in AA-induced EC migration. We report that TRPV4, an AA-activated channel, is differentially expressed in EC derived from human breast carcinomas (BTEC) as compared with 'normal' EC (HMVEC). BTEC display a significant increase in TRPV4 expression, which was correlated with greater Ca(2+) entry, induced by AA or 4αPDD (a selective TRPV4 agonist) in the tumor-derived ECs. Wound-healing assays revealed a key role of TRPV4 in regulating cell migration of BTEC but not HMVEC. Knockdown of TRPV4 expression completely abolished AA-induced BTEC migration, suggesting that TRPV4 mediates the pro-angiogenic effects promoted by AA. Furthermore, pre-incubation of BTEC with AA induced actin remodeling and a subsequent increase in the surface expression of TRPV4. This was consistent with the increased plasma membrane localization of TRPV4 and higher AA-stimulated Ca(2+) entry in the migrating cells. Together, the data presented herein demonstrate that: (1) TRPV4 is differentially expressed in tumor-derived versus 'normal' EC; (2) TRPV4 has a critical role in the migration of tumor-derived but not 'normal' EC migration; and (3) AA induces actin remodeling in BTEC, resulting in a corresponding increase of TRPV4 expression in the plasma membrane. We suggest that the latter is critical for migration of EC and thus in promoting angiogenesis and tumor growth.