VEGF and angiopoietin signaling in tumor angiogenesis and metastasis

Long non-coding RNA taurine upregulated 1 enhances tumor-induced angiogenesis through inhibiting microRNA-299 in human glioblastoma

Angiogenesis is one of the critical biological elements affecting the development and progression of cancer. Long non-coding RNAs (lncRNAs) are important regulators and aberrantly expressed in various types of human cancer. Our previous studies indicated that lncRNA taurine upregulated 1 (TUG1) implicated in the regulation of blood-tumor barrier permeability; however, its role in glioblastoma angiogenesis still unclear. Here we demonstrated that TUG1 was up-expressed in human glioblastoma tissues and glioblastoma cell lines. Knockdown of TUG1 remarkably suppressed tumor-induced endothelial cell proliferation, migration and tube formation as well as reducing spheroid-based angiogenesis ability in vitro, which are the critical steps for tumor angiogenesis. Besides, knockdown of TUG1 significantly increased the expression of mircroRNA-299 (miR-299), which was down-expressed in glioblastoma tissues and glioblastoma cell lines. Bioinformatics analysis and luciferase reporter assay revealed that TUG1 influenced tumor angiogenesis via directly binding to the miR-299 and there was a reciprocal repression between TUG1 and miR-299 in the same RNA-induced silencing complex. Moreover, knockdown of TUG1 reduced the expression of vascular endothelial growth factor A (VEGFA), which was defined as a functional downstream target of miR-299. In addition, knockdown of TUG1, shown in the in vivo studies, has effects on suppressing tumor growth, reducing tumor microvessel density and decreasing the VEGFA expression by upregulating miR-299 in xenograft glioblastoma model. Overall, the results demonstrated that TUG1 enhances tumor-induced angiogenesis and VEGF expression through inhibiting miR-299. Also, the inhibition of TUG1 could provide a novel therapeutic target for glioblastoma treatment.

Association between vascular endothelial growth factor expression and lymph node metastasis in cervical cancer: A meta-analysis

AIM

The expression of vascular endothelial growth factor (VEGF) by cancer cells has been identified as a factor that is associated with lymph node metastasis (LNM) in some cancers, but an accurate description of the relation between VEGF and LNM in cervical cancer is lacking. We conducted a concurrent meta-analysis to investigate this issue.

METHODS

We searched PubMed and EMBASE for articles addressing the association between VEGF and cervical cancer. We used stata 12.0 and calculated the crude odds ratios (OR) and corresponding 95% confidence intervals (CI). Heterogeneity between the studies included was assessed by Cochran's Q-test.

RESULTS

Overall, 16 relevant studies with 426 cases and 751 controls were included in our study. The results demonstrated that cervical cancer patients with VEGF-positive expression had a 2.87-fold higher risk of LNM than patients without VEGF-positive expression (95%CI = 1.85-4.44, P < 0.001). Furthermore, subgroup analysis by ethnicity revealed that VEGF-positive expression could increase the risk of LNM in cervical cancer among Asian populations (OR = 2.55, 95%CI = 1.61-4.03, P < 0.001) and Caucasian populations (OR = 8.81, 95%CI = 2.78-27.88, P < 0.001). Moreover, subgroup analysis by country revealed that VEGF-positive expression could increase the risk of LNM in cervical cancer among Chinese populations (OR = 3.38, 95%CI = 2.18-5.25, P < 0.001) but not among Korean populations (P = 0.84) or Japanese populations (P = 0.06). Subgroup analysis based on sample size proved that VEGF-positive expression was statistically associated with LNM in a large sample group.

CONCLUSION

Our study revealed that VEGF-positive expression is related with higher risk of LNM in cervical cancer.

TRIM11 overexpression promotes proliferation, migration and invasion of lung cancer cells

BACKGROUND

Tripartite Motif Containing 11 (TRIM11), a member of TRIM proteins, is overexpressed in high-grade gliomas and plays an oncogenic function in glioma biology. However, little is known about the role of TRIM11 in lung cancer.

METHODS

We analyzed TRIM11 mRNA expression in lung cancer tissues and adjacent non-neoplastic tissues by real-time PCR. We then explored the function of TRIM11 in lung cancer cells by small interfering RNA-mediated downregulation of this protein followed by analyses of cell proliferation, migration and invasion.

RESULTS

TRIM11 was highly expressed in lung cancer tissues and lung cancer cell lines. The higher expression of TRIM11 was correlated with the poorer prognosis of patients. Suppressing of TRIM11 expression in lung cancer cells with higher expression of TRIM11 (A549 and NCI-H446 cells) significantly reduced cell growth, motility and invasiveness. We further demonstrated that knockdown of TRIM11 affected the expression of cell proliferation-related proteins (Cyclin D1 and PCNA), and epithelial-mesenchymal transformation-related proteins (VEGF, MMP-2, MMP-9, Twist1, Snail and E-cadherin). The activity of ERK and PI3K/AKT was also suppressed in TRIM11 knocked down cells. Further experiments in lung cells with lower expression of TRIM11 (NCI-H460 and NCI-H1975 cells) with AKT inhibitor suggested that TRIM11 may promote cell motility and invasiveness through AKT pathway.

CONCLUSIONS

Our results indicate that TRIM11 acts as an oncogene in lung cancer through promoting cell growth, migration and invasion. Our findings may have important implication for the detection and treatment of lung cancer.

Intravenous Administration Is an Effective and Safe Route for Cancer Gene Therapy Using the Bifidobacterium-Mediated Recombinant HSV-1 Thymidine Kinase and Ganciclovir

The herpes simplex virus thymidine kinase/ganciclovir (HSV TK/GCV) system is one of the best studied cancer suicide gene therapy systems. Our previous study showed that caspase 3 expression was upregulated and bladder tumor growth was significantly reduced in rats treated with a combination of Bifidobacterium (BF) and HSV TK/GCV (BF-rTK/GCV). However, it was raised whether the BF-mediated recombinant thymidine kinase combined with ganciclovir (BF-rTK/GCV) was safe to administer via venous for cancer gene therapy. To answer this question, the antitumor effects of BF-rTK/GCV were mainly evaluated in a xenograft nude mouse model bearing MKN-45 gastric tumor cells. The immune response, including analysis of cytokine profiles, was analyzed to evaluate the safety of intramuscular and intravenous injection of BF-rTK in BALB/c mice. The results suggested that gastric tumor growth was significantly inhibited in vivo by BF-rTK/GCV. However, the BF-rTK/GCV had no effect on mouse body weight, indicating that the treatment was safe for the host. The results of cytokine profile analysis indicated that intravenous injection of a low dose of BF-rTK resulted in a weaker cytokine response than that obtained with intramuscular injection. Furthermore, immunohistochemical analysis showed that intravenous administration did not affect the expression of immune-associated TLR2 and TLR4. Finally, the BF-rTK/GCV inhibited vascular endothelial growth factor (VEGF) expression in mouse model, which is helpful for inhibiting of tumor angiogenesis. That meant intravenous administration of BF-rTK/GCV was an effective and safe way for cancer gene therapy.

Angiopoietin 2 expression in the cornea and its control of corneal neovascularisation

PURPOSE

To define proangiogenic angiopoietin 2 (ANG2) expression and role(s) in human and mouse vascularised corneas. Further, to evaluate the effect of ANG2 inhibition on corneal neovascularisation (CNV).

METHODS

CNV was induced in FVB mice by means of intrastromal suture placement. One group of animals was sacrificed 10 days later; corneas were immunostained for ANG2 and compared with (i) mouse non-vascularised corneas and (ii) human vascularised and non-vascularised corneas. A second group of CNV animals was treated systemically with an anti-ANG2 antibody. After 10 days, the corneas were whole-mounted, stained for CD31 and LYVE1 and lymphatic/blood vessels quantified. In another set of experiments, the corneal basal Bowman membrane was either (i) removed or (ii) left in place. After 2 or 10 days the corneas were removed and immunostained for collagen IV, ANG2, CD31, LYVE1, CD11b and MRC1 markers.

RESULTS

In human beings and mice, ANG2 is expressed only in the epithelium, and, mildly, in the endothelium, of the avascular cornea. Instead, it is expressed in the epithelium, endothelium and stroma of vascularised corneas. Disruption of the Bowman membrane is associated with a significant increase of (i) ANG2 stromal expression and (ii) proangiogenic macrophage infiltration in the corneal stroma. Finally, blocking ANG2 significantly reduced hemangiogenesis, lymphangiogenesis and macrophage infiltration.

CONCLUSIONS

Balancing proper healing and good vision is crucial in the cornea, constantly exposed to potential injuries. In this paper, we suggest the existence of a mechanism regulating the onset of inflammation (and associated CNV) depending on injury severity.

Selective portal vein injection for the design of syngeneic models of liver malignancy

Liver metastases are the most frequent cause of death due to colorectal cancer (CRC). Syngeneic orthotopic animal models, based on the grafting of cancer cells or tissue in host liver, are efficient systems for studying liver tumors and their (patho)physiological environment. Here we describe selective portal vein injection as a novel tool to generate syngeneic orthotopic models of liver tumors that avoid most of the weaknesses of existing syngeneic models. By combining portal vein injection of cancer cells with the selective clamping of distal liver lobes, tumor growth is limited to specific lobes. When applied on MC-38 CRC cells and their mouse host C57BL6, selective portal vein injection leads with 100% penetrance to MRI-detectable tumors within 1 wk, followed by a steady growth until the time of death (survival ∼7 wk) in the absence of extrahepatic disease. Similar results were obtained using CT-26 cells and their syngeneic Balb/c hosts. As a proof of principle, lobe-restricted liver tumors were also generated using Hepa1-6 (C57BL6-syngeneic) and TIB-75 (Balb/c-syngeneic) hepatocellular cancer cells, demonstrating the general applicability of selective portal vein injection for the induction of malignant liver tumors. Selective portal vein injection is technically straightforward, enables liver invasion via anatomical routes, preserves liver function, and provides unaffected liver tissue. The tumor models are reproducible and highly penetrant, with survival mainly dependent on the growth of lobe-restricted liver malignancy. These models enable biological studies and preclinical testing within short periods of time.

Discovery of Potent VEGFR-2 Inhibitors based on Furopyrimidine and Thienopyrimidne Scaffolds as Cancer Targeting Agents

Vascular endothelial growth factor receptor-2 (VEGFR-2) plays a crucial role in cancer angiogenesis. In this study, a series of novel furo[2,3-d]pyrimidine and thieno[2,3-d]pyrimidine based-derivatives were designed and synthesized as VEGFR-2 inhibitors, in accordance to the structure activity relationship (SAR) studies of known type II VEGFR-2 inhibitors. The synthesized compounds were evaluated for their ability to in vitro inhibit VEGFR-2 kinase enzyme. Seven compounds (15b, 16c, 16e, 21a, 21b, 21c and 21e) demonstrated highly potent dose-related VEGFR-2 inhibition with IC₅₀ values in nanomolar range, of which the thieno[2,3-d]pyrimidine based-derivatives (21b, 21c and 21e) exhibited IC₅₀ values of 33.4, 47.0 and 21 nM respectively. Moreover, furo[2,3-d]pyrimidine-based derivative (15b) showed the strongest inhibition of human umbilical vein endothelial cells (HUVEC) proliferation with 99.5% inhibition at 10 μM concentration. Consistent with our in vitro findings, compounds (21b and 21e) orally administered at 5 and 10 mg/kg/day for 8 consecutive days demonstrated potent anticancer activity in Erhlich ascites carcinoma (EAC) solid tumor murine model. Such compounds blunted angiogenesis in EAC as evidenced by reduced percent microvessel via decreasing VEGFR-2 phosphorylation with subsequent induction of apoptotic machinery. Furthermore, Miles vascular permeability assay confirmed their antiangiogenic effects in vivo. Intriguingly, such compounds showed no obvious toxicity.

Noncyanogenic Cyanoglucoside Cyclooxygenase Inhibitors from Simmondsia chinensis

Two new noncyanogenic cyanoglucoside dimers, simmonosides A and B (1 and 2), were identified from the aqueous extract of jojoba (Simmondsia chinensis) leaves. Compounds 1 and 2 are the first examples of noncyanogenic cyanoglucoside dimers containing a unique four-membered ring, representing novel dimerization patterns at α,β-unsaturated carbons of a nitrile group in 1 and γ,δ-unsaturated carbons in 2. Their structures were elucidated based on spectroscopic evidence and electronic circular dichroism (ECD) calculations. Compounds 1 and 2 exhibit promising COX-2 inhibition activity, with IC50 values of 13.5 and 11.4 μM, respectively.

VEGF-D promotes pulmonary oedema in hyperoxic acute lung injury

Leakage of fluid from blood vessels, leading to oedema, is a key feature of many diseases including hyperoxic acute lung injury (HALI), which can occur when patients are ventilated with high concentrations of oxygen (hyperoxia). The molecular mechanisms driving vascular leak and oedema in HALI are poorly understood. VEGF‐D is a protein that promotes blood vessel leak and oedema when overexpressed in tissues, but the role of endogenous VEGF‐D in pathological oedema was unknown. To address these issues, we exposed Vegfd‐deficient mice to hyperoxia. The resulting pulmonary oedema in Vegfd‐deficient mice was substantially reduced compared to wild‐type, as was the protein content of bronchoalveolar lavage fluid, consistent with reduced vascular leak. Vegf‐d and its receptor Vegfr‐3 were more highly expressed in lungs of hyperoxic, versus normoxic, wild‐type mice, indicating that components of the Vegf‐d signalling pathway are up‐regulated in hyperoxia. Importantly, VEGF‐D and its receptors were co‐localized on blood vessels in clinical samples of human lungs exposed to hyperoxia; hence, VEGF‐D may act directly on blood vessels to promote fluid leak. Our studies show that Vegf‐d promotes oedema in response to hyperoxia in mice and support the hypothesis that VEGF‐D signalling promotes vascular leak in human HALI. © 2016 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Combination of vatalanib and a 20-HETE synthesis inhibitor results in decreased tumor growth in an animal model of human glioma

Background

Due to the hypervascular nature of glioblastoma (GBM), antiangiogenic treatments, such as vatalanib, have been added as an adjuvant to control angiogenesis and tumor growth. However, evidence of progressive tumor growth and resistance to antiangiogenic treatment has been observed. To counter the unwanted effect of vatalanib on GBM growth, we have added a new agent known as N-hydroxy-N′-(4-butyl-2 methylphenyl)formamidine (HET0016), which is a selective inhibitor of 20-hydroxyeicosatetraenoic acid (20-HETE) synthesis. The aims of the studies were to determine 1) whether the addition of HET0016 can attenuate the unwanted effect of vatalanib on tumor growth and 2) whether the treatment schedule would have a crucial impact on controlling GBM.

Methods

U251 human glioma cells (4×10⁵) were implanted orthotopically. Two different treatment schedules were investigated. Treatment starting on day 8 (8–21 days treatment) of the tumor implantation was to mimic treatment following detection of tumor, where tumor would have hypoxic microenvironment and well-developed neovascularization. Drug treatment starting on the same day of tumor implantation (0–21 days treatment) was to mimic cases following radiation therapy or surgery. There were four different treatment groups: vehicle, vatalanib (oral treatment 50 mg/kg/d), HET0016 (intraperitoneal treatment 10 mg/kg/d), and combined (vatalanib and HET0016). Following scheduled treatments, all animals underwent magnetic resonance imaging on day 22, followed by euthanasia. Brain specimens were equally divided for immunohistochemistry and protein array analysis.

Results

Our results demonstrated a trend that HET0016, alone or in combination with vatalanib, is capable of controlling the tumor growth compared with that of vatalanib alone, indicating attenuation of the unwanted effect of vatalanib. When both vatalanib and HET0016 were administered together on the day of the tumor implantation (0–21 days treatment), tumor volume, tumor blood volume, permeability, extravascular and extracellular space volume, tumor cell proliferation, and cell migration were decreased compared with that of the vehicle-treated group.

Conclusion

HET0016 is capable of controlling tumor growth and migration, but these effects are dependent on the timing of drug administration. The addition of HET0016 to vatalanib may attenuate the unwanted effect of vatalanib.

Regulation of COX-2 expression and epithelial-to-mesenchymal transition by hypoxia-inducible factor-1α is associated with poor prognosis in hepatocellular carcinoma patients post TACE surgery

Currently, it is not entirely clear whether hypoxia-inducible factor-1α (HIF-1α) is involved in the regulation of COX-2 expression and epithelial-to-mesenchymal transition (EMT), and whether these events affect the prognosis of hepatocellular carcinoma (HCC) patients treated with transcatheter arterial chemoembolization (TACE). In this report the relationship between HIF-1α and COX-2 protein expression, EMT in tumor specimens from HCC patients after TACE surgery and the clinical significance of HIF-1α and COX-2 expression were analyzed using statistical approaches. HepG2 cells treated with CoCl₂ was employed as a hypoxia cell model in vitro to study hypoxia-induced HIF-1α, COX-2 expression, and EMT alteration. The results showed that HIF-1α and COX-2 protein expression increased in HCC tissues after TACE surgery. Moreover, there was positive correlation between upregulation of HIF-1α and COX-2. Elevated expression of HIF-1α increased both Snail and Vimentin protein expression, while it reduced E-cadherin protein expression. It was further verified that hypoxia enhanced protein expression of HIF-1α and COX-2 in HepG2 cells treated with CoCl₂. Upregulation of HIF-1α and COX-2, together with EMT alteration resulted in increased migration and invasion of HepG2 cells under hypoxia. In conclusion, TACE surgery results in aggravated hypoxia status, leading to increased HIF-1α protein expression in HCC tissue. To adapt to hypoxic environment, HIF-1α stimulates COX-2 protein expression and promotes EMT process in hepatocellular cancer cells, which enhances HCC invasion and metastasis, and might contribute to poor prognosis in HCC patients post TACE treatment.

Metformin prevents aggressive ovarian cancer growth driven by high-energy diet: similarity with calorie restriction

Caloric restriction (CR) was recently demonstrated by us to restrict ovarian cancer growth in vivo. CR resulted in activation of energy regulating enzymes adenosine monophosphate activated kinase (AMPK) and sirtuin 1 (SIRT1) followed by downstream inhibition of Akt-mTOR. In the present study, we investigated the effects of metformin on ovarian cancer growth in mice fed a high energy diet (HED) and regular diet (RD) and compared them to those seen with CR in an immunocompetent isogeneic mouse model of ovarian cancer. Mice either on RD or HED diet bearing ovarian tumors were treated with 200 mg/kg metformin in drinking water. Metformin treatment in RD and HED mice resulted in a significant reduction in tumor burden in the peritoneum, liver, kidney, spleen and bowel accompanied by decreased levels of growth factors (IGF-1, insulin and leptin), inflammatory cytokines (MCP-1, IL-6) and VEGF in plasma and ascitic fluid, akin to the CR diet mice. Metformin resulted in activation of AMPK and SIRT1 and inhibition of pAkt and pmTOR, similar to CR. Thus metformin can closely mimic CR's tumor suppressing effects by inducing similar metabolic changes, providing further evidence of its potential not only as a therapeutic drug but also as a preventive agent.

Targeting of cancer‑associated fibroblasts enhances the efficacy of cancer chemotherapy by regulating the tumor microenvironment

Cancer-associated fibroblasts (CAFs), key components of the tumor stroma, can regulate tumorigenesis by altering the tumor microenvironment in variety of ways to promote angiogenesis, recruit inflammatory immune cells and remodel the extracellular matrix. Using a murine xenograft model of colon carcinoma, the present study observed that oxaliplatin increased the accumulation of CAFs and stimulated the production of cytokines associated with CAFs. When oxaliplatin was combined with the small-molecule dipeptidyl peptidase inhibitor PT-100, which inhibits CAFs by targeting fibroblast activation protein (FAP), the accumulation of CAFs was markedly reduced, xenograft tumor growth was significantly suppressed and the survival of the mice increased, compared to those of mice treated with oxaliplatin or PT-100 alone. Furthermore, the xenograft tumor tissues of mice treated with oxaliplatin and PT-100 contained lower numbers of tumor-associated macrophages and dendritic cells, expressed lower levels of cytokines associated with CAFs and had a lower density of CD31+ endothelial cells. The present study demonstrated that pharmacological inhibition of CAFs improved the response to chemotherapy, reduced the recruitment of immune tumor-promoting cells and inhibited angiogenesis. Combining chemotherapy with agents which target CAFs may represent a novel strategy for improving the efficacy of chemotherapy and reducing chemoresistance.

VEGF/NRP-1axis promotes progression of breast cancer via enhancement of epithelial-mesenchymal transition and activation of NF-κB and β-catenin

Autocrine vascular endothelial growth factor (VEGF) can regulate the survival and progression of cancers through its various receptors. But the mechanisms and mediators for these functions are largely uncovered, especially in breast cancer. We examined the potential roles and mechanisms of VEGF/neuropilin-1 (NRP-1) axis in regulating the tumorigenesis and metastasis of breast cancer and found the expression of VEGF and NRP-1 correlated with aggressiveness of breast cancer. Knockdown of VEGF or NRP-1 inhibited the proliferation, migration and invasion, but enhanced the apoptosis of MDA-MB-231 cells. In contrast, induction of NRP-1 over-expression promoted the proliferation, migration and invasion of MCF-7 cells. VEGF or NRP-1 silencing attenuated the epithelial-mesenchymal transition (EMT) process and the activation of NF-κBp65, but enhanced GSK-3β expression in MDA-MB-231 cells while NRP-1 over-expression reversed the effects in MCF-7 cells. Treatment with hVEGF165 did not change the inhibition in NRP-1 silencing MDA-MB-231 cells, but enhanced the aggressiveness of NRP-1 over-expressing MCF-7 cells. In addition, VEGF-silencing inhibited the growth and metastasis of implanted MDA-MB-231 tumors in vivo. Our novel data suggest that the positive regulation of the VEGF/NRP-1 axis on the tumorigenesis and metastasis of breast cancer may be associated with enhancing the EMT process and the NF-κB and β-catenin signaling. Hence, the VEGF/NRP-1 axis may be a valuable target for design of therapies for intervention of breast cancer.

Hypoxia-inducible factor 1 upregulation of both VEGF and ANGPTL4 is required to promote the angiogenic phenotype in uveal melanoma

PURPOSE

Expression of the hypoxia-inducible factor (HIF)-1-regulated gene product, vascular endothelial growth factor (VEGF), correlates with tumor vascularity in patients with uveal melanoma (UM). While the relationship between HIF-1 and VEGF in cancer is well-studied, their relative contribution to the angiogenic phenotype in UM has not previously been interrogated. Here we evaluate the contribution of HIF-1, VEGF, and a second HIF-1-regulated gene product, angiopoietin-like 4 (ANGPTL4), to angiogenesis in UM.

EXPERIMENTAL DESIGN

UM cells were examined for expression of HIF-1α, VEGF, and ANGPTL4. Their contribution to the angiogenic potential of UM cells was assessed using the endothelial cell tubule formation and directed in vivo angiogenesis assays. These results were corroborated in tissue from UM animal models and in tissue from patients with UM.

RESULTS

Inhibition of VEGF partially reduced tubule formation promoted by conditioned medium from UM cells. Inhibition of ANGPTL4, which was highly expressed in hypoxic UM cells, a UM orthotopic transplant model, a UM tumor array, and vitreous samples from UM patients, inhibited the angiogenic potential of UM cells in vitro and in vivo; this effect was additive to VEGF inhibition.

CONCLUSIONS

Targeting both ANGPTL4 and VEGF may be required for the effective inhibition of angiogenesis in UM.

NAADP-Dependent Ca(2+) Signaling Controls Melanoma Progression, Metastatic Dissemination and Neoangiogenesis

A novel transduction pathway for the powerful angiogenic factor VEGF has been recently shown in endothelial cells to operate through NAADP-controlled intracellular release of Ca²⁺. In the present report the possible involvement of NAADP-controlled Ca²⁺ signaling in tumor vascularization, growth and metastatic dissemination was investigated in a murine model of VEGF-secreting melanoma. Mice implanted with B16 melanoma cells were treated with NAADP inhibitor Ned-19 every second day for 4 weeks and tumor growth, vascularization and metastatization were evaluated. Control specimens developed well vascularized tumors and lung metastases, whereas in Ned-19-treated mice tumor growth and vascularization as well as lung metastases were strongly inhibited. In vitro experiments showed that Ned-19 treatment controls the growth of B16 cells in vitro, their migratory ability, adhesive properties and VEGFR2 expression, indicating NAADP involvement in intercellular autocrine signaling. To this regard, Ca²⁺ imaging experiments showed that the response of B16 cells to VEGF stimulation is NAADP-dependent. The whole of these observations indicate that NAADP-controlled Ca²⁺ signaling can be relevant not only for neoangiogenesis but also for direct control of tumor cells.

Overview of pre-clinical and clinical studies targeting angiogenesis in pancreatic ductal adenocarcinoma

The importance of angiogenesis in pancreatic ductal adenocarcinoma (PDAC) and its therapeutic potential have been explored in both pre-clinical and clinical studies. Human PDACs overexpress a number of angiogenic factors and their cognate high-affinity receptors, and anti-angiogenic agents reduce tumor volume, metastasis, and microvessel density (MVD), and improve survival in subcutaneous and orthotopic pre-clinical models. Nonetheless, clinical trials using anti-angiogenic therapy have been overwhelmingly unsuccessful. This review will focus on these pre-clinical and clinical studies, the potential reasons for failure in the clinical setting, and ways these shortcomings could be addressed in future investigations of angiogenic mechanisms in PDAC.

Neutrophil-lymphocyte ratio as a prognostic factor for gallbladder carcinoma after radical resection

AIM: To explore whether neutrophil/lymphocyte ratio (NLR) can be used as a prognostic indicator of gallbladder carcinoma (GBC) after radical resection.

METHODS: We retrospectively collected the data of GBC patients who underwent radical resection at Tongji Hospital from January 2007 to June 2010. According to the preoperative NLR value, the patients were divided into a low NLR group (NLR < 5.0) and a high NLR group (NLR ≥ 5.0). We compared the demographic, clinical and pathological variables of the two groups. Univariate analysis was used to identify the factors affecting the prognosis of GBC, and the significant factors entered into a COX regression model to identify independent prognostic factors for GBC after radical surgery.

RESULTS: A total of 90 patients were included in this study. The 5-year survival rates of the low NLR group and high NLR group were 70.9% and 27.6% (P < 0.05), respectively. Univariate analysis showed that tumor differentiation, lymph node metastasis, liver invasion, T stage, TNM stage and NLR were factors affecting prognosis of GBC. COX regression analysis indicated that NLR was an independent predictive factor for prognosis of GBC after operation (P < 0.05).

CONCLUSION: NLR can serve as a prognostic indicator in GBC patients who underwent radical therapy. GBC patients with elevated NLR have a worse prognosis after operation.

Determination of cell metabolite VEGF₁₆₅ and dynamic analysis of protein-DNA interactions by combination of microfluidic technique and luminescent switch-on probe

In this paper, we rationally design a novel G-quadruplex-selective luminescent iridium (III) complex for rapid detection of oligonucleotide and VEGF165 in microfluidics. This new probe is applied as a convenient biosensor for label-free quantitative analysis of VEGF165 protein from cell metabolism, as well as for studying the kinetics of the aptamer-protein interaction combination with a microfluidic platform. As a result, we have successfully established a quantitative analysis of VEGF165 from cell metabolism. Furthermore, based on the principles of hydrodynamic focusing and diffusive mixing, different transient states during kinetics process were monitored and recorded. Thus, the combination of microfluidic technique and G-quadruplex luminescent probe will be potentially applied in the studies of intramolecular interactions and molecule recognition in the future.

Dietary energy balance modulates ovarian cancer progression and metastasis

A high energy balance, or caloric excess, accounts as a tumor promoting factor, while a negative energy balance via caloric restriction, has been shown to delay cancer progression. The effect of energy balance on ovarian cancer progression was investigated in an isogeneic immunocompetent mouse model of epithelial ovarian cancer kept on a regimen of regular diet, high energy diet (HED) and calorie restricted diet (CRD), prior to inoculating the animals intraperitoneally with the mouse ovarian surface epithelial ID8 cancer cells. Tumor evaluation revealed that mice group on HED displayed the most extensive tumor formation with the highest tumor score at all organ sites (diaphragm, peritoneum, bowel, liver, kidney, spleen), accompanied with increased levels of insulin, leptin, insulin growth factor-1 (IGF-1), monocyte chemoattractant protein-1 (MCP-1), VEGF and interleukin 6 (IL-6). On the other hand, the mice group on CRD exhibited the least tumor burden associated with a significant reduction in levels of insulin, IGF-1, leptin, MCP-1, VEGF and IL-6. Immunohistochemistry analysis of tumors from HED mice showed higher activation of Akt and mTOR with decreased adenosine monophosphate activated kinase (AMPK) and SIRT1 activation, while tumors from the CRD group exhibited the reverse profile. In conclusion, ovarian cancer growth and metastasis occurred more aggressively under HED conditions and was significantly curtailed under CRD. The suggested mechanism involves modulated secretion of growth factors, cytokines and altered regulation of AMPK and SIRT1 that converges on mTOR inhibition. While the role of a high energy state in ovarian cancer has not been confirnmed in the literature, the current findings support investigating the potential impact of diet modulation as adjunct to other anticancer therapies and as possible individualized treatment strategy of epithelial ovarian cancer.

Motif mimetic of epsin perturbs tumor growth and metastasis

Tumor angiogenesis is critical for cancer progression. In multiple murine models, endothelium-specific epsin deficiency abrogates tumor progression by shifting the balance of VEGFR2 signaling toward uncontrolled tumor angiogenesis, resulting in dysfunctional tumor vasculature. Here, we designed a tumor endothelium-targeting chimeric peptide (UPI) for the purpose of inhibiting endogenous tumor endothelial epsins by competitively binding activated VEGFR2. We determined that the UPI peptide specifically targets tumor endothelial VEGFR2 through an unconventional binding mechanism that is driven by unique residues present only in the epsin ubiquitin-interacting motif (UIM) and the VEGFR2 kinase domain. In murine models of neoangiogenesis, UPI peptide increased VEGF-driven angiogenesis and neovascularization but spared quiescent vascular beds. Further, in tumor-bearing mice, UPI peptide markedly impaired functional tumor angiogenesis, tumor growth, and metastasis, resulting in a notable increase in survival. Coadministration of UPI peptide with cytotoxic chemotherapeutics further sustained tumor inhibition. Equipped with localized tumor endothelium-specific targeting, our UPI peptide provides potential for an effective and alternative cancer therapy.

Bone marrow derived myeloid cells orchestrate antiangiogenic resistance in glioblastoma through coordinated molecular networks

Glioblastoma (GBM) is a hypervascular and malignant form of brain tumors. Anti-angiogenic therapies (AAT) were used as an adjuvant against VEGF-VEGFR pathway to normalize blood vessels in clinical and preclinical studies, which resulted into marked hypoxia and recruited bone marrow derived cells (BMDCs) to the tumor microenvironment (TME). In vivo animal models to track BMDCs and investigate molecular mechanisms in AAT resistance are rare. We exploited recently established chimeric mouse to develop orthotopic U251 tumor, which uses as low as 5 × 10(6) GFP+ BM cells in athymic nude mice and engrafted >70% GFP+ cells within 14 days. Our unpublished data and published studies have indicated the involvement of immunosuppressive myeloid cells in therapeutic resistance in glioma. Similarly, in the present study, vatalanib significantly increased CD68+ myeloid cells, and CD133+, CD34+ and Tie2+ endothelial cell signatures. Therefore, we tested inhibition of CSF1R+ myeloid cells using GW2580 that reduced tumor growth by decreasing myeloid (Gr1+ CD11b+ and F4/80+) and angiogenic (CD202b+ and VEGFR2+) cell signatures in TME. CSF1R blockade significantly decreased inflammatory, proangiogenic and immunosuppressive molecular signatures compared to vehicle, vatalanib or combination. TCK1 or CXCL7, a potent chemoattractant and activator of neutrophils, was observed as most significantly decreased cytokine in CSF1R blockade. ERK MAPK pathway was involved in cytokine network regulation. In conclusion, present study confirmed the contribution of myeloid cells in GBM development and therapeutic resistance using chimeric mouse model. We identified novel molecular networks including CXCL7 chemokine as a promising target for future studies. Nonetheless, survival studies are required to assess the beneficial effect of CSF1R blockade.

Chemiluminescence detection of a protein through the aptamer-controlled catalysis of a porphyrin probe

Sensitive and selective protein detection based on the aptamer-controlled noncovalent porphyrin probe self-assembly is reported for the first time. Vascular endothelial growth factor (VEGF) is a predominant biomarker in cancer angiogenesis. In this work, a positively charged porphyrin probe, manganese(III) meso-tetrakis(N-methylpyridinum-4-yl)porphyrin (Mn-PyP), was prepared. Using it as a catalyst, a label-free chemiluminescence (CL) turn-on approach for sensitive VEGF detection is developed. Mn-PyP could catalyze the luminol CL reaction. The VEGF aptamer could induce aggregation of Mn-PyP. As a result, the Mn-PyP-catalyzed CL reaction is efficiently suppressed. Upon the addition of VEGF, the specific binding of VEGF to the aptamer weakens the interactions between the aptamer and Mn-PyP. The Mn-PyP monomers are released, and a turn-on CL signal is thus detected. Our method is quite sensitive; 50 pM of VEGF could be easily detected. It is also very selective against other proteins. Our assay provides an aptamer-based efficient way for protein quantification.

A novel vascular pattern promotes metastasis of hepatocellular carcinoma in an epithelial-mesenchymal transition-independent manner

Early metastasis is responsible for frequent relapse and high mortality of hepatocellular carcinoma (HCC), but its underlying mechanisms remain unclear. Epithelial-mesenchymal transition (EMT) has been considered a key event in metastasis. Based on histological examination of serial HCC sections and three-dimensional reconstruction, we found a novel and prevalent vascular pattern, vessels that encapsulated tumor clusters (VETC) and formed cobweb-like networks. The presence of VETC (VETC(+) ) predicted higher metastasis and recurrence rates of HCC. Using clinical samples and mouse xenograft models, we further showed that VETC was composed of functional vessels with blood perfusion and induced by tumor cells at the early stage of HCC. Subsequent investigations revealed that HCC cell-derived angiopoietin-2 was a prerequisite for VETC formation and that the VETC pattern was a critical factor promoting HCC metastasis as knockdown of angiopoietin-2 abolished this vascular pattern and consequently attenuated in vivo tumor metastasis. Interestingly, abrogation of EMT by knockdown of Snail or Slug significantly diminished in vivo metastasis of VETC(-) xenografts but did not affect that of VETC(+) ones, although silencing of Snail or Slug substantially reduced the in vitro migration of both VETC(+) and VETC(-) HCC cells. In contrast to human VETC(-) cases, EMT signatures were rarely observed in VETC(+) cases with metastatic potential. Further analysis revealed that VETC provided an efficient metastasis mode by facilitating the release of whole tumor clusters into the bloodstream.

CONCLUSION

Our findings identify a novel metastasis mechanism that relies on vascular pattern but is independent of EMT, which may provide new targets for antimetastasis therapy and offer a basis for selecting patients who may benefit from certain molecularly targeted drugs.

Angiopoietin-2 blocking antibodies reduce early atherosclerotic plaque development in mice

OBJECTIVE

Angiopoietin-2 (Ang-2) blocking agents are currently undergoing clinical trials for use in cancer treatment. Ang-2 has also been associated with rupture-prone atherosclerotic plaques in humans, suggesting a role for Ang-2 in plaque stability. Despite the availability of Ang-2 blocking agents, their clinical use is still lacking. Our aim was to establish if Ang-2 has a role in atheroma development and in the transition of subclinical to clinically relevant atherosclerosis. We investigated the effect of antibody-mediated Ang-2 blockage on atherogenesis after in a mouse model of atherosclerosis.

METHODS

Hypercholesterolemic (low-density lipoprotein receptor(-/-) apolipoprotein B(100/100)) mice were subjected to high-cholesterol diet for eight weeks, one group with and one group without Ang-2 blocking antibody treatment during weeks 4-8.To enhance plaque development, a peri-adventitial collar was placed around the carotid arteries at the start of antibody treatment. Aortic root, carotid arteries and brachiocephalic arteries were analyzed to evaluate the effect of Ang-2 blockage on atherosclerotic plaque size and stable plaque characteristics.

RESULTS

Anti-Ang-2 treatment reduced the size of fatty streaks in the brachiocephalic artery (-72%, p < 0.05). In addition, antibody-mediated Ang-2 blockage reduced plasma triglycerides (-27%, p < 0.05). In contrast, Ang-2 blockage did not have any effect on the size or composition (collagen content, macrophage percentage, adventitial microvessel density) of pre-existing plaques in the aortic root or collar-induced plaques in the carotid artery.

CONCLUSIONS

Ang-2 blockage was beneficial as it decreased fatty streak formation and plasma triglyceride levels, but had no adverse effect on pre-existing atherosclerosis in hypercholesterolemic mice.

Antitumor and antimetastatic activities of chloroform extract of medicinal mushroom Cordyceps taii in mouse models

BACKGROUND

Cordyceps taii, an entomogenous fungus native to south China, is a folk medicine with varieties of pharmacological activities including anticancer effect. To validate the ethnopharmacological claim against cancer, the antitumor and antimetastatic activities of chloroform extract of C. taii (CFCT) were investigated in vivo.

METHODS

The in vitro cytotoxic activities of CFCT against human lung cancer (A549) and gastric cancer (SGC-7901) cells were evaluated using the Sulforhodamine B (SRB) assay. In vivo anti tumor and antimetastatic activities, Kunming mice bearing sarcoma 180 and C57BL/6 mice bearing melanoma B16F10 were employed, respectively. The antitumor effects of CFCT were completely evaluated on the basis of the tumor weight, survival time, histologic analysis, and immune organ indices. The histopathological change, metastatic foci and malignant melanoma specific marker HMB45 in the lung tissue were detected for the evaluation of the antimetastatic activity of CFCT.

RESULTS

CFCT exhibited dose- and time-dependent cytotoxicities against A549 and SGC-7901 cells with the IC50 values of 30.2 and 65.7 μg/mL, respectively. Furthermore, CFCT at a dose of 50 or 100 mg/kg could significantly inhibit the tumor growth in vivo and prolonged the survival time in two different models as compared with the model group, especially when combined with the CTX at a low dose rate. And it also increased spleen index of Kunming mice and thymus index of C57BL/6 mice. Meanwhile, histologic analysis illustrated that CFCT alone or in combination with CTX could induce tumor tissue necrosis of both models. In addition, CFCT at a dose of 50 or 100 mg/kg inhibited the lung metastasis of melanoma B16F10 in tumor-bearing C57BL/6 mice. The antimetastatic effect was also observed when CFCT was used in combination with CTX. In comparison to any other groups, CFCT at a dose of 100 mg/kg could effectively enhance the GSH-Px activities of various tissues in tumor-bearing C57BL/6 mice.

CONCLUSIONS

These findings demonstrate that CFCT has potent in vivo antitumor and antimetastatic activities, and may be helpful to the development of anticancer chemopreventive agents from C. taii.

Control of the blood-brain barrier function in cancer cell metastasis

Cerebral metastases are the most common brain neoplasms seen clinically in the adults and comprise more than half of all brain tumours. Actual treatment options for brain metastases that include surgical resection, radiotherapy and chemotherapy are rarely curative, although palliative treatment improves survival and life quality of patients carrying brain-metastatic tumours. Chemotherapy in particular has also shown limited or no activity in brain metastasis of most tumour types. Many chemotherapeutic agents used systemically do not cross the blood-brain barrier (BBB), whereas others may transiently weaken the BBB and allow extravasation of tumour cells from the circulation into the brain parenchyma. Increasing evidence points out that the interaction between the BBB and tumour cells plays a key role for implantation and growth of brain metastases in the central nervous system. The BBB, as the tightest endothelial barrier, prevents both early detection and treatment by creating a privileged microenvironment. Therefore, as observed in several in vivo studies, precise targetting the BBB by a specific transient opening of the structure making it permeable for therapeutic compounds, might potentially help to overcome this difficult clinical problem. Moreover, a better understanding of the molecular features of the BBB, its interrelation with metastatic tumour cells and the elucidation of cellular mechanisms responsible for establishing cerebral metastasis must be clearly outlined in order to promote treatment modalities that particularly involve chemotherapy. This in turn would substantially expand the survival and quality of life of patients with brain metastasis, and potentially increase the remission rate. Therefore, the focus of this review is to summarise the current knowledge on the role and function of the BBB in cancer metastasis.

Serum Angiopoietin Levels are Different in Acute and Chronic Myeloid Neoplasms: Angiopoietins do not only Regulate Tumor Angiogenesis

Molecular balance between Angiopoietin-1 (Ang-1) and Angiopoietin-2 (Ang-2) has important effects in tumor angiogenesis. Ang-2 was shown to be elevated and proved to be a prognostic factor in acute myeloid leukemia (AML). To date studies revealed increased angiogenesis in bone marrows (BMs) of both myeloproliferative neoplasm (MPN) and AML patients. We conducted this study to demonstrate circulating levels of Ang-1 and Ang-2 in MPN patients since no data exists in literature. Thirty-three newly diagnosed MPN, 27 newly diagnosed AML patients and 25 controls (HC) were enrolled and Angiopoietin levels were determined with ELISA. We found that Ang-1 levels were higher whereas Ang-2 levels were lower in MPN and HC when compared to AML. Our results suggest that though angiogenesis is increased in both AML and MPN, angiopoietin serum level profile of the two diseases are different, and MPN patients have similar Ang-1 and Ang-2 levels as HC. We conclude that, according to our results Ang-1 and Ang-2 do not only regulate tumor angiogenesis and the difference between angiopoietin levels of acute and chronic myeloid neoplasms could be a reflection of other effects of these growth factors on tumor malignancy.

The roles of ADAMTS in angiogenesis and cancer

Angiogenesis is an indispensable mechanism involved in both physiological processes and various pathological conditions, such as inflammation, aberrant wound healing, tumor progression, and metastasis. Among many angiogenic stimulators and inhibitors, vascular endothelial growth factor (VEGF) is regarded as one of the most important members of the signaling protein family involved in blood vessel formation and maturation. The a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTSs) proteins are a family of multifunctional proteinases. Such proteolytic enzymes are associated with various physiological processes, such as collagen maturation, organogenesis, angiogenesis, and reproduction. Importantly, deficiency or overexpression of certain ADAMTS proteinases has been shown to be directly involved in a number of serious diseases, including tumor progression and metastasis. This review explores in-depth the connections between ADAMTS proteinases as positive/negative mediators during angiogenesis and VEGF.

Oxygen-induced cell migration and on-line monitoring biomarkers modulation of cervical cancers on a microfluidic system

In this work, we report an integrated microfluidic device for cell co-culture under different concentrations of oxygen, in which the secreted protein VEGF165 was on-line qualitatively and semi-quantitatively analyzed by functional nucleic acid, hemin, ABTS and peroxide system. This microfluidic platform allowed investigation of various oxygen and distances effect on cell-to-cell communication. Besides, the microfluidic device was used for real-time analysis of VEGF165 protein by aptamer-functionalized microchannels. Under 5% O2 condition, we found that the migration of CaSki cells was faster than the migration of human umbilical vein endothelial cells. However, the migration of CaSki cells was slower than the migration of HUVECs under 15% O2 condition. Moreover, the shorter intercellular distances, the quicker cells migration. Furthermore, HIF-1α and VEGF165 genes, ROS were analyzed, and the results would provide new perspectives for the diagnosis and medical treatment of cervical cancer.

Association between the expression of T-cadherin and vascular endothelial growth factor and the prognosis of patients with gastric cancer

T-cadherin has been identified as a tumor-suppressor gene in several types of cancer. The present study aimed to investigate the association of the expression of T-cadherin with angiogenesis, and to evaluate its prognostic value for patients with primary gastric cancer. Gastric cancer tissues and matched adjacent tissues from 166 patients receiving surgical resection were included in the present study. The expression of T-cadherin was detected using immunohistochemistry, western blotting and reverse transcription-quantitative polymerase chain reaction. The expression of vascular epidermal growth factor (VEGF) was detected using immunohistochemistry, and its association with the expression of T-cadherin was analyzed. In addition, the association between the expression of T-cadherin and clinicopathological features were analyzed. The mRNA and protein expression levels of T-cadherin were significantly lower in the gastric cancer tissue compared with the corresponding adjacent normal tissue (P<0.05). The expression of VEGF was not associated with the expression of T-cadherin in the gastric cancer tissue. The decreased protein expression of T-cadherin correlated with smoking, larger tumor size (diameter, >4 cm), lymph node metastasis and a higher tumor-lymph node-metastasis stage (P<0.05 or P<0.01). However, the expression of T-cadherin was not correlated with gender, age, alcohol intake, Helecobacter pylori infection or differentiation (P>0.05). The multivariate analysis demonstrated that the expression of T-cadherin was an independent prognostic factor for the overall survival rate of patients with gastric cancer. This data suggested that the downregulation of T-cadherin may contribute to gastric cancer progression, representing a useful biomarker for predicting the biological behavior and prognosis of gastric cancer. However, no significant association was observed between the expression of VEGF and T-cadherin.

The TIE Receptor Family

The endothelial TIE1 and TIE2 receptor tyrosine kinases form a distinct subfamily characterized by their unique extracellular domains. Together with the angiopoietin growth factors (ANGPT1, ANGPT2, ANGPT4, also abbreviated as ANG), the TIE receptors form an endothelial specific signaling pathway with important functions in the regulation of lymphatic and cardiovascular development and vascular homeostasis. Angiopoietins exist in multimeric forms that activate the TIE receptors via unique mechanism. In endothelial cell–cell contacts, angiopoietins induce the formation of homomeric in trans TIE receptor complexes extending across the cell junctions, whereas matrix-bound angiopoietin-1 (ANG1) activates the TIE receptors in a cis configuration. In comparison to the vascular endothelial growth factor receptors, the TIE receptors undergo little ubiquitin-mediated degradation after activation, whereas TIE2 signaling is negatively regulated by the vascular endothelial protein tyrosine phosphatase, VE-PTP. ANG1 activation of TIE2 supports vascular stabilization, whereas angiopoietin-2 (ANG2), a context-dependent weak TIE2 agonist/antagonist, promotes pathological tumor angiogenesis, vascular permeability, and inflammation. Recently, ANG2 has been found to mediate some of its vascular destabilizing and angiogenic functions via integrin signalling. The circulating levels of ANG2 are increased in cancer, and in several human diseases associated with inflammation and vascular leak, for example, in sepsis. Blocking of ANG2 has emerged as a potential novel therapeutic strategy for these diseases. In addition, preclinical results demonstrate that genetic TIE1 deletion in mice inhibits the vascularization and growth of tumor isografts and protects from atherosclerosis, with little effect on normal vascular homeostasis in adult mice. The ability of the ANG-TIE pathway to control vessel stability and angiogenesis makes it an interesting vascular target for the treatment of the various diseases.

The native structure of annexin A2 peptides in hydrophilic environment determines their anti-angiogenic effects

The progression of aggressive cancer occurs via angiogenesis and metastasis makes these processes important targets for the development of anti-cancer agents. However, recent studies have raised the concern that selective inhibition of angiogenesis results in a switch towards increased tumour growth and metastasis. Since Annexin A2 (AnxA2) is involved in both angiogenesis and metastasis, it may serve as an ideal target for the simultaneous inhibition of both processes. Based on the discovery that domains I (D(I)) and IV (D(IV)) of AnxA2 are potent inhibitors of angiogenesis, we designed seven peptides derived from these domains based on AnxA2 crystal structures. The peptides were expressed as fusion peptides to increase their folding and solubility. Light scattering, far-UV circular dichroism and thermal transition analyses were employed to investigate their aggregation tendencies, α-helical propensity and stability, respectively. 2,2,2-trifluoroethanol (50%) increased the α-helical propensities of all peptides, indicating that they may favour a hydrophobic environment, but did not enhance their thermal stability. D(I)-P2 appears to be the most stable and folded peptide in a hydrophilic environment. The secondary structure of D(I)-P2 was confirmed by nuclear magnetic resonance spectra. The effect of the seven AnxA2 peptides on the formation and integrity of capillary-like networks was studied in a co-culture system mimicking many of the angiogenesis-related processes. Notably, D(I)-P2 inhibited significantly network formation in this system, indicating that the folded D(I)-P2 peptide interferes with vascular endothelial growth factor-dependent pro-angiogenic processes. Thus, this peptide has the potential of being developed further as an anti-angiogenic drug.

Trebananib (AMG 386) plus weekly paclitaxel with or without bevacizumab as first-line therapy for HER2-negative locally recurrent or metastatic breast cancer: A phase 2 randomized study

INTRODUCTION

This phase 2 randomized study evaluated trebananib (AMG 386), a peptide-Fc fusion protein that inhibits angiogenesis by neutralizing the interaction of angiopoietin-1 and -2 with Tie2, in combination with paclitaxel with or without bevacizumab in previously untreated patients with HER2-negative locally recurrent/metastatic breast cancer.

METHODS

Patients received paclitaxel 90 mg/m(2) once weekly (3-weeks-on/1-week-off) and were randomly assigned 1:1:1:1 to also receive blinded bevacizumab 10 mg/kg once every 2 weeks plus either trebananib 10 mg/kg once weekly (Arm A) or 3 mg/kg once weekly (Arm B), or placebo (Arm C); or open-label trebananib 10 mg/kg once a week (Arm D). Progression-free survival was the primary endpoint.

RESULTS

In total, 228 patients were randomized. Median estimated progression-free survival for Arms A, B, C, and D was 11.3, 9.2, 12.2, and 10 months, respectively. Hazard ratios (95% CI) for Arms A, B, and D versus Arm C were 0.98 (0.61-1.59), 1.12 (0.70-1.80), and 1.28 (0.79-2.09), respectively. The objective response rate was 71% in Arm A, 51% in Arm B, 60% in Arm C, and 46% in Arm D. The incidence of grade 3/4/5 adverse events was 71/9/4%, 61/14/5%, 62/16/3%, and 52/4/7% in Arms A/B/C/D. In Arm D, median progression-free survival was 12.8 and 7.4 months for those with high and low trebananib exposure (AUCss ≥ 8.4 versus < 8.4 mg·h/mL), respectively.

CONCLUSIONS

There was no apparent prolongation of estimated progression-free survival with the addition of trebananib to paclitaxel and bevacizumab at the doses tested. Toxicity was manageable. Exposure-response analyses support evaluation of combinations incorporating trebananib at doses > 10 mg/kg in this setting.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT00511459.

Translational horizons in the tumor microenvironment: harnessing breakthroughs and targeting cures

Chemotherapy and targeted therapy have opened new avenues in clinical oncology. However, there is a lack of response in a substantial percentage of cancer patients and diseases frequently relapse in those who even initially respond. Resistance is, at present, the major barrier to conquering cancer, the most lethal age-related pathology. Identification of mechanisms underlying resistance and development of effective strategies to circumvent treatment pitfalls thereby improving clinical outcomes remain overarching tasks for scientists and clinicians. Growing bodies of data indicate that stromal cells within the genetically stable but metabolically dynamic tumor microenvironment confer acquired resistance against anticancer therapies. Further, treatment itself activates the microenvironment by damaging a large population of benign cells, which can drastically exacerbate disease conditions in a cell nonautonomous manner, and such off-target effects should be well taken into account when establishing future therapeutic rationale. In this review, we highlight relevant biological mechanisms through which the tumor microenvironment drives development of resistance. We discuss some unsolved issues related to the preclinical and clinical trial paradigms that need to be carefully devised, and provide implications for personalized medicine. In the long run, an insightful and accurate understanding of the intricate signaling networks of the tumor microenvironment in pathological settings will guide the design of new clinical interventions particularly combinatorial therapies, and it might help overcome, or at least prevent, the onset of acquired resistance.

PI3K at the crossroads of tumor angiogenesis signaling pathways

Tumors need blood vessels for their growth, thus providing the rationale for antiangiogenic therapy in cancer treatment. However, intrinsic and acquired resistance and low response rates have turned out to be major limitations of antiangiogenic therapy. This emphasizes the need to further understand how the vasculature in cancer can be targeted. Although endothelial cells (ECs) rely on multiple growth factors and cytokines to grow, antiangiogenic therapies have mainly centered on targeting vascular endothelial growth factor (VEGF). Phosphoinositide 3-kinases (PI3Ks) form a family of 8 isoenzymes with non-redundant functions in normal biology and cancer. The subgroup of class I PI3Ks are situated at the crossroad of a plethora of proangiogenic signals and control cell growth, survival, motility, and metabolism. These isoenzymes have pleiotropic roles in the tumor microenvironment, including cell-autonomous functions in ECs, underscoring the complexity of targeting this pathway in cancer. Here, we describe how the PI3K axis influences angiogenesis in different cell compartments and summarize the diversity of vascular responses to PI3K inhibition. Targeting PI3K signaling by isoform-selective inhibitors, together with readjusting the current doses below the maximum tolerated dose, may improve clinical responses to class I PI3K anticancer agents.

An artificial blood vessel implanted three-dimensional microsystem for modeling transvascular migration of tumor cells

Reproducing a tumor microenvironment consisting of blood vessels and tumor cells for modeling tumor invasion in vitro is particularly challenging. Here, we report an artificial blood vessel implanted 3D microfluidic system for reproducing transvascular migration of tumor cells. The transparent, porous and elastic artificial blood vessels are obtained by constructing polysaccharide cellulose-based microtubes using a chitosan sacrificial template, and possess excellent cytocompatibility, permeability, and mechanical characteristics. The artificial blood vessels are then fully implanted into the collagen matrix to reconstruct the 3D microsystem for modeling transvascular migration of tumor cells. Well-defined simulated vascular lumens were obtained by proliferation of the human umbilical vein endothelial cells (HUVECs) lining the artificial blood vessels, which enables us to reproduce structures and functions of blood vessels and replicate various hemodynamic parameters. Based on this model, the adhesion and transvascular migration of tumor cells across the artificial blood vessel have been well reproduced.

Targeting vascular pericytes in hypoxic tumors increases lung metastasis via angiopoietin-2

Strategies to target angiogenesis include inhibition of the vessel-stabilizing properties of vascular pericytes. Pericyte depletion in early-stage non-hypoxic tumors suppressed nascent angiogenesis, tumor growth, and lung metastasis. In contrast, pericyte depletion in advanced-stage hypoxic tumors with pre-established vasculature resulted in enhanced intra-tumoral hypoxia, decreased tumor growth, and increased lung metastasis. Furthermore, depletion of pericytes in post-natal retinal blood vessels resulted in abnormal and leaky vasculature. Tumor transcriptome profiling and biological validation revealed that angiopoietin signaling is a key regulatory pathway associated with pericyte targeting. Indeed, pericyte targeting in established mouse tumors increased angiopoietin-2 (ANG2/Angpt2) expression. Depletion of pericytes, coupled with targeting of ANG2 signaling, restored vascular stability in multiple model systems and decreased tumor growth and metastasis. Importantly, ANGPT2 expression correlated with poor outcome in patients with breast cancer. These results emphasize the potential utility of therapeutic regimens that target pericytes and ANG2 signaling in metastatic breast cancer.

Direct endothelial junction restoration results in significant tumor vascular normalization and metastasis inhibition in mice

Tumor blood vessels are leaky and immature, which causes inadequate blood supply to tumor tissues resulting in hypoxic microenvironment and promotes metastasis. Here we have explored tumor vessel modulating activity of Sac-1004, a recently developed molecule in our lab, which directly potentiates VE-cadherin-mediated endothelial cell junction. Sac-1004 could enhance vascular junction integrity in tumor vessels and thereby inhibit vascular leakage and enhance vascular perfusion. Improved perfusion enabled Sac-1004 to have synergistic anti-tumor effect on cisplatin-mediated apoptosis of tumor cells. Interestingly, characteristics of normalized blood vessels namely reduced hypoxia, improved pericyte coverage and decreased basement membrane thickness were readily observed in tumors treated with Sac-1004. Remarkably, Sac-1004 was also able to inhibit lung and lymph node metastasis in MMTV and B16BL6 tumor models. This was in correlation with a reduction in epithelial-to-mesenchymal transition of tumor cells with considerable diminution in expression of related transcription factors. Moreover, cancer stem cell population dropped substantially in Sac-1004 treated tumor tissues. Taken together, our results showed that direct restoration of vascular junction could be a significant strategy to induce normalization of tumor blood vessels and reduce metastasis.

Hsa-microRNA-181a is a regulator of a number of cancer genes and a biomarker for endometrial carcinoma in patients: a bioinformatic and clinical study and the therapeutic implication

The aberrant expression of human microRNA-181a-1 (hsa-miR-181a) has been implicated in the pathogenesis of various cancers, serving as an oncogene or a tumor suppressor. However, the role of hsa-miR-181a in the pathogenesis of endometrial carcinoma (EC) and its clinical significance are unclear. This study aimed to search for the molecular targets of hsa-miR-181a using bioinformatic tools and then determine the expression levels of hsa-miR-181a in normal, hyperplasia, and EC samples from humans. To predict the targets of hsa-miR-181a, ten different algorithms were used, including miRanda-mirSVR, DIANA microT v5.0, miRDB, RNA22 v2, TargetMiner, TargetScan 6.2, PicTar, MicroCosm Targets v5, and miRWALK. Two algorithms, TarBase 6.0 and miRTarBase, were used to identify the validated targets of hsa-miR-181a-5p (a mature product of hsa-miR-181a), and the web-based Database for Annotation, Visualization and Integrated Discovery (DAVID) 6.7 was used to provide biological functional interpretation of the validated targets of hsa-miR-181a-5p. A total of 78 formalin-fixed, paraffin-embedded tissue specimens from 65 patients and 13 healthy subjects were collected and examined, including normal endometrium (n=13), endometrial hyperplasia (n=18), and EC (37 type I and 10 type II EC cases). Our bioinformatic studies have showed that hsa-miR-181a might regulate a large number of target genes that are important in the regulation of critical cell processes, such as cell fate, cell survival, metabolism, and cell death. To date, 313 targets of hsa-miR-181a have been validated, and 22 of these targets are cancer genes. The precision of predictions by all the algorithms for hsa-miR-181a-1’s targets was low. Many of these genes are involved in tumorigenesis of various cancers, including EC, based on the DAVID and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. In comparison with normal endometrial tissue, the expression level of hsa-miR-181a was significantly increased in type I and type II EC (P<0.05), and type II EC exhibited a significant higher expression level of hsa-miR-181a than that in type I EC (P<0.05). In addition, there was a significant increase in the expression level of hsa-miR-181a in type II EC compared with endometrial hyperplasia (P<0.05). Taken together, these results suggest that hsa-miR-181a may serve as an oncogene in endometrial tumorigenesis and that hsa-miR-181a might be used as a new biomarker in the prediction of prognosis of EC in clinical practice. More functional and mechanistic studies are needed to validate the role of hsa-miR-181a in the development, progression, and metastasis of EC.

VEGF-D and A Preoperative Serum Levels Predict Nodal and Distant Metastases in Differentiated Thyroid Cancer Patients

BACKGROUND

Preoperative tumor aggressiveness biomarkers may help surgeons decide the extent of an operation. However, whether serum angiogenetic factors can be used to predict the prognosis of patients with differentiated thyroid cancer is still unclear.

METHODS

Seventy-six DTC patients were prospectively recruited. Preoperative serum samples were collected and measured for Tie-2, Ang-1, Ang-2, VEGF-A, and VEGF-D levels. The potential correlations between their serum levels and clinicopathologic features as well as their prognoses were analyzed.

RESULTS

Older age (>45 years old) and higher VEGF-A serum levels were independent predictors of extrathyroidal extension. The VEGF-D serum level was an independent factor for lymph node metastases and VEGF-A was an independent factor for distant metastases. None of these serum angiogenetic factors were significantly different between patients who were disease free and those with recurrences. The presence of lymph node metastases was the only independent factor for recurrence over the 2-year follow-up.

CONCLUSION

Preoperative serum VEGF-A and VEGF-D levels were significantly elevated in DTC patients with distant and lymph node metastases. These findings, when combined with other clinicopathological factors, may help in surgical decisions.

Role of the angiopoietin/Tie system in pregnancy (Review)

Angiopoietin-1 and -2 are endogenous ligands for the vascular endothelium-specific receptor tyrosine kinase Tie-2. The angiopoietin/Tie system plays a critical role in the regulation of endothelial cell survival and vascular maturation and stability. Apart from its well-established role in vascular morphogenesis, emerging data support the involvement of angiopoietins in inflammation and various malignancies. Previous studies have underlined the significance of several angiogenic factors in normal placental development. In addition, angiogenic imbalance is observed in pregnancy complications related to impaired placentation, such as preeclampsia (PE) and intrauterine growth restriction (IUGR). However, there is only limited information available on the role of the angiopoietin/Tie system in the establishment of a competent feto-maternal vascular system. In this review, we present the current knowledge regarding the role of angiopoietins in normal pregnancy and pregnancy complications.

Total saponins from Albizia julibrissin inhibit vascular endothelial growth factor-mediated angiogenesis in vitro and in vivo

Dried stem bark from Albizia julibrissin (AJ) is a highly valued Traditional Chinese Medicine, which has been shown to suppress tumor growth and angiogenesis. Total saponins from AJ (TSAJ) are one of the most bioactive components of AJ extract. The present study evaluated the anti-tumor and anti-angiogenic effects of TSAJ in vitro and in vivo. The anti-angiogenic activity of TSAJ was investigated by measuring the effects on vascular endothelial growth factor (VEGF)-induced proliferation, migration and tube formation of Ea.hy926 endothelial cells in vitro. The expression levels of proteins associated with VEGF-induced angiogenesis were determined by western blotting. Furthermore, in vivo Matrigel™ plug and H22 hepatoma tumor models were used to verify the anti-angiogenic effects of TSAJ. The present study demonstrated that TSAJ significantly inhibited VEGF-mediated endothelial cell proliferation, migration and tube formation of Ea.hy926 cells in vitro. The anti-angiogenic effects of TSAJ were modulated by suppression of phosphorylated-(p-) focal adhesion kinase, p-Akt, and p-extracellular signal-regulated kinase in the VEGF/VEGF receptor 2 (R2) signaling pathway. Furthermore, oral administration of TSAJ significantly inhibited tumor growth and tumor-induced angiogenesis, as well as the formation of functional vessels, in the Matrigel™ plug model. These results suggest that TSAJ may be a potential anti-angiogenic agent that targets the VEGF/VEGFR2 signaling pathway, and inhibits tumor-induced angiogenesis.

MiR-221-induced PUMA silencing mediates immune evasion of bladder cancer cells

Immune evasion of cancer cells is mainly due to the impaired transduction of apoptotic signals from immune cells to cancer cells, as well as inhibition of subsequent apoptosis signal cascades within the cancer cells. Over the past few decades, the research has focused more on the impaired transduction of the apoptotic signal from immune cells to cancer cells, rather than inhibition of the intracellular signaling pathways. In this study, miR‑221 inhibitor was transfected into bladder cancer cell lines 5637, J82 and T24 to repress the expression of miR‑221. As a result, the repression of miR‑221 on p53 upregulated modulator of apoptosis (PUMA) was abolished, resulting in increased expression of the pro-apoptotic Bax and reduced expression of the anti-apoptotic Bcl-2, which promotes apoptosis of bladder cancer cells. The expression of MMP-2, MMP-9 and VEGF-C were reduced, resulting in reduced invasiveness and infiltration capability of bladder cancer cells, thereby inhibiting the immune evasion of bladder cancer cells.

Propolis: A Complex Natural Product with a Plethora of Biological Activities That Can Be Explored for Drug Development

The health industry has always used natural products as a rich, promising, and alternative source of drugs that are used in the health system. Propolis, a natural resinous product known for centuries, is a complex product obtained by honey bees from substances collected from parts of different plants, buds, and exudates in different geographic areas. Propolis has been attracting scientific attention since it has many biological and pharmacological properties, which are related to its chemical composition. Several in vitro and in vivo studies have been performed to characterize and understand the diverse bioactivities of propolis and its isolated compounds, as well as to evaluate and validate its potential. Yet, there is a lack of information concerning clinical effectiveness. The goal of this review is to discuss the potential of propolis for the development of new drugs by presenting published data concerning the chemical composition and the biological properties of this natural compound from different geographic origins.