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Prevention of inflammatory angiogenesis is critical for suppressing chronic inflammation and inhibiting inflammatory tissue damage. Angiogenesis is particularly detrimental to the cornea because pathologic growth of new blood vessels can lead to marked vision impairment and even loss of vision. The expression of proinflammatory cytokines by injured tissues exacerbates the inflammatory cascade, including angiogenesis. IL-36 cytokine, a subfamily of the IL-1 superfamily, consists of three proinflammatory agonists, IL-36α, IL-36β, and IL-36γ, and an IL-36 receptor antagonist (IL-36Ra). Data from the current study indicate that human vascular endothelial cells constitutively expressed the cognate IL-36 receptor. The current investigation, for the first time, characterized the direct contribution of IL-36γ to various angiogenic processes. IL-36γ up-regulated the expression of vascular endothelial growth factors (VEGFs) and their receptors VEGFR2 and VEGFR3 by human vascular endothelial cells, suggesting that IL-36γ mediates the VEGF-VEGFR signaling by endothelial cells. Moreover, by using a naturally occurring antagonist IL-36Ra in a murine model of inflammatory angiogenesis, this study demonstrated that blockade of endogenous IL-36γ signaling results in significant retardation of inflammatory angiogenesis. The current investigation on the proangiogenic function of IL-36γ provides novel evidence of the development of IL-36γ-targeting strategies to hamper inflammatory angiogenesis., (Copyright © 2023 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

Recently, the medications used for the severe form of the coronavirus disease-19 (COVID-19) therapy are of particular interest. In this sense, it has been supposed that anti-VEGF compounds would be good candidates in the face of "cytokine storm" and intussuscepted angiogenesis due to having an appreciable anti-inflammatory effect. Therefore, they can be subjected to therapeutic protocols to manage acute respiratory distress syndrome (ARDS). Since the compelling evidence emphasized that VEGFs contribute to the inflammatory process and play a mainstay role in disease pathogenesis, in this review, we aimed to highlight the VEGF's plausible participation in the cytokine storm exacerbation in COVID-19. Next, the recent clinical advances regarding the anti-VEGF medications, including humanized monoclonal antibody, immunosuppressant, a tyrosine kinase inhibitor, and a cytokine inhibitor, have been addressed in the setting of COVID-19 treatment in critically ill patients. Together, retrieving the increased level of VEGF subsets, as well as antagonizing VEGF related receptors, could be helpful for the treatment of COVID-19, especially in those suffering from ARDS., (Copyright © 2021 Elsevier B.V. All rights reserved.)

There are limited options for targeted therapies for colorectal cancer (CRC). Anti-EGFR therapy is limited to CRC without KRAS mutations. Even worse, most of CRC are refractory to currently immune checkpoint blockade. DKK2, which is upregulated in CRC, was recently found to suppress host immune responses, and its blockage effectively impeded tumor progression in benign genetic CRC models in our previous study. Here, our recent study demonstrated that in human CRC tumor samples expressing high levels of DKK2, DKK2 blockade caused stronger activation of tumor infiltrating CD8 + T cells in ex vivo culture. Intriguingly, we observed a correlation of high DKK2 expression with increased lymph node metastasis prevalence in these CRC patients as well. Furthermore, in a mouse genetic CRC model with mutations in APC and KRAS, which more closely mimics advanced human CRC, we confirmed the tumor inhibitory effect of DKK2 blockade, which significantly retarded tumor progression and extended survival, with increased immune effector cell activation and reduced angiogenesis. Based on this, we performed a combined administration of DKK2 blockade with sub-optimal anti-VEGFR treatment and observed a synergetic effect on suppressing tumor angiogenesis and progression, as well as extending survival, better than those of every single therapy. Thus, this study provides further evidence for the potential therapeutic application of DKK2 blockade in the clinical treatment of human CRC., (Copyright © 2020 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Background: Dual blockade of PD-L1 and VEGF has enhanced anticancer immunity through multiple mechanisms and augmented antitumour activity in multiple malignancies. We aimed to assess the efficacy and safety of atezolizumab (anti-PD-L1) alone and combined with bevacizumab (anti-VEGF) in patients with unresectable hepatocellular carcinoma., Methods: GO30140 is an open-label, multicentre, multiarm, phase 1b study that enrolled patients at 26 academic centres and community oncology practices in seven countries worldwide. The study included five cohorts, and the two hepatocellular carcinoma cohorts, groups A and F, are described here. Inclusion criteria for these two groups included age 18 years and older; histologically, cytologically, or clinically (per American Association for the Study of Liver Diseases criteria) confirmed unresectable hepatocellular carcinoma that was not amenable to curative treatment; no previous systemic treatment; and Eastern Cooperative Oncology Group performance status of 0 or 1. In group A, all patients received atezolizumab (1200 mg) and bevacizumab (15 mg/kg) intravenously every 3 weeks. In group F, patients were randomly assigned (1:1) to receive intravenous atezolizumab (1200 mg) plus intravenous bevacizumab (15 mg/kg) every 3 weeks or atezolizumab alone by interactive voice-web response system using permuted block randomisation (block size of two) and stratification factors of geographical region; macrovascular invasion, extrahepatic spread, or both; and baseline α-fetoprotein concentration. Primary endpoints were confirmed objective response rate in all patients who received the combination treatment for group A and progression-free survival in the intention-to-treat population in group F, both assessed by an independent review facility according to Response Evaluation Criteria in Solid Tumors version 1.1. In both groups, safety was assessed in all patients who received at least one dose of any study treatment. This study is registered with ClinicalTrials.gov, NCT02715531, and is closed to enrolment., Findings: In group A, 104 patients were enrolled between July 20, 2016, and July 31, 2018, and received atezolizumab plus bevacizumab. With a median follow-up of 12·4 months (IQR 8·0-16·2), 37 (36%; 95% CI 26-46) of 104 patients had a confirmed objective response. The most common grade 3-4 treatment-related adverse events were hypertension (13 [13%]) and proteinuria (seven [7%]). Treatment-related serious adverse events occurred in 25 (24%) patients and treatment-related deaths in three (3%) patients (abnormal hepatic function, hepatic cirrhosis, and pneumonitis). In group F, 119 patients were enrolled and randomly assigned (60 to atezolizumab plus bevacizumab; 59 to atezolizumab monotherapy) between May 18, 2018, and March 7, 2019. With a median follow-up of 6·6 months (IQR 5·5-8·5) for the atezolizumab plus bevacizumab group and 6·7 months (4·2-8·2) for the atezolizumab monotherapy group, median progression-free survival was 5·6 months (95% CI 3·6-7·4) versus 3·4 months (1·9-5·2; hazard ratio 0·55; 80% CI 0·40-0·74; p=0·011). The most common grade 3-4 treatment-related adverse events in group F were hypertension (in three [5%] patients in the atezolizumab plus bevacizumab group; none in the atezolizumab monotherapy group) and proteinuria (in two [3%] patients in the atezolizumab plus bevacizumab group; none in the atezolizumab monotherapy group). Treatment-related serious adverse events occurred in seven (12%) patients in the atezolizumab plus bevacizumab group and two (3%) patients in the atezolizumab monotherapy group. There were no treatment-related deaths., Interpretation: Our study shows longer progression-free survival with a combination of atezolizumab plus bevacizumab than with atezolizumab alone in patients with unresectable hepatocellular carcinoma not previously treated with systemic therapy. Therefore, atezolizumab plus bevacizumab might become a promising treatment option for these patients. This combination is being compared with standard-of-care sorafenib in a phase 3 trial., Funding: F Hoffmann-La Roche/Genentech., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

A type of sorafenib- (SOR-) loaded long-circulating nanoliposome was constructed, and the targeting performance and antitumor effects of the prepared liposome were evaluated in the present study. Polyethylene glycol- (PEG-) modified long-circulating nanoliposomes (LC-NPs) were designed and prepared using reverse evaporation, and the LC-NPs were used for delivering sorafenib (LC-PEG-SOR-NPs). Then, the anti-VEGFR antibody as a targeting moiety was chemically coupled with LC-PEG-SOR-NPs to form liver cancer-targeted nanoliposomes (anti-VEGFR-LC-PEG-SOR-NPs). The drug entrapment and loading efficiency were measured. And the cancer-targeting performance and therapeutic efficiency were evaluated both in vitro and in vivo . The anti-VEGFR-LC-PEG-SOR-NPs with an average of 119.8 ± 4.2 nm showed a uniform spherical structure. The drug entrapment and loading efficiency were 92.5% and 18.5%, respectively. The killing efficiency of anti-VEGFR-LC-PEG-SOR-NPs was up to 18% after incubating with liver cancer cells for 72 h. Furthermore, the anti-VEGFR-LC-PEG-SOR-NPs could actively target at the tumor region and could efficiently inhibit tumor growth with negligible side effects. This newly designed nanoliposomes had desirable dispersibility, high drug entrapment efficiency, tumor targeting and therapeutic efficiency, and good safety. As a biocompatible nanocomposite, it was promising to become a novel and useful tumor-targeting nanodrug for liver cancer therapy., Competing Interests: The authors declare that they have no competing interests., (Copyright © 2020 Haiwei Ye et al.)

With current screening for sight threatening retinopathy of prematurity (ROP) <10% of screened infants need treatment. Prediction models based on birth characteristics, postnatal weight gain and other factors have been developed to reduce examinations in low-risk infants. A model based on advanced statistics using data from >7000 infants registered in the Swedish ROP registry is being developed. Based on birth characteristics only, it appears to predict total risk of ROP-treatment as well as models including weight measurements. Treatment risk peaked at 12 weeks of age. Laser therapy is the method of choice for severe ROP. Anti-VEGF therapies are implemented worldwide despite insufficient knowledge of choice of drug, dosage and long term systemic effects. Prevention of ROP may be achieved through oxygen control and provision of the mother's breastmilk. Other interventions such as supplementation with long chain polyunsaturated fatty acids and preservation of fetal haemoglobin are investigated., (Copyright © 2019 Elsevier B.V. All rights reserved.)

In addition to the crucial role in promoting the growth of tumor vessels, vascular endothelial growth factor (VEGF) is also immunosuppressive. VEGF can inhibit the function of T cells, increase the recruitment of regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs), and hinder the differentiation and activation of dendritic cells (DCs). Recent studies have investigated the role of antiangiogenic agents in antitumor immunity, especially in recent 3 years. Therefore, it is necessary to update the role of targeting VEGF/VEGFR in antitumor immunity. In this review, we focus on the latest clinical and preclinical findings on the modulatory role of antiangiogenic agents targeting VEGF/VEGFR in immune cells, including effector T cells, Tregs, MDSCs, DCs, tumor-associated macrophages, and mast cells. Our review will be potentially helpful for the development of combinations of angiogenesis inhibitors with immunological modulators.

Angiogenesis is defined as the formation of new blood vessels from preexisting vessels and has been characterized as an essential process for tumor cell proliferation and viability. This has led to the development of pharmacological agents for anti-angiogenesis to disrupt the vascular supply and starve tumor of nutrients and oxygen, primarily through blockade of VEGF/VEGFR signaling. This effort has resulted in 11 anti-VEGF drugs approved for certain advanced cancers, alone or in combination with chemotherapy or other targeted therapies. But this success had only limited impact on overall survival of cancer patients and rarely resulted in durable responses. Given the recent success of immunotherapies, combinations of anti-angiogenics with immune checkpoint blockers have become an attractive strategy. However, implementing such combinations will require a better mechanistic understanding of their interaction. Due to overexpression of pro-angiogenic factors in tumors, their vasculature is often tortuous and disorganized, with excessively branched leaky vessels. This enhances vascular permeability, which in turn is associated with high interstitial fluid pressure, and a reduction in blood perfusion and oxygenation. Judicious dosing of anti-angiogenic treatment can transiently normalize the tumor vasculature by decreasing vascular permeability and improving tumor perfusion and blood flow, and synergize with immunotherapy in this time window. However, anti-angiogenics may also excessively prune tumor vessels in a dose and time-dependent manner, which induces hypoxia and immunosuppression, including increased expression of the immune checkpoint programmed death receptor ligand (PD-L1). This review focuses on revisiting the concept of anti-angiogenesis in combination with immunotherapy as a strategy for cancer treatment.

Antiangiogenesis-based cancer therapies, specifically those targeting the VEGF-A/VEGFR2 pathway, have been approved for subsets of solid tumors. However, these therapies result in an increase in hematologic adverse events. We surmised that both the bone marrow vasculature and VEGF receptor-positive hematopoietic cells could be impacted by VEGF pathway-targeted therapies. We used a mouse model of spontaneous breast cancer to decipher the mechanism by which VEGF pathway inhibition alters hematopoiesis. Tumor-bearing animals, while exhibiting increased angiogenesis at the primary tumor site, showed signs of shrinkage in the sinusoidal bone marrow vasculature accompanied by an increase in the hematopoietic stem cell-containing Lin-cKit(+)Sca1(+) (LKS) progenitor population. Therapeutic intervention by targeting VEGF-A, VEGFR2, and VEGFR3 inhibited tumor growth, consistent with observed alterations in the primary tumor vascular bed. These treatments also displayed systemic effects, including reversal of the tumor-induced shrinkage of sinusoidal vessels and altered population balance of hematopoietic stem cells in the bone marrow, manifested by the restoration of sinusoidal vessel morphology and hematopoietic homeostasis. These data indicate that tumor cells exert an aberrant systemic effect on the bone marrow microenvironment and VEGF-A/VEGFR targeting restores bone marrow function., (©2015 American Association for Cancer Research.)

RIG-I-mediated type I interferon (IFN) production and nuclease-mediated viral RNA degradation are essential for antiviral innate immune responses. DDX60 is an IFN-inducible cytoplasmic helicase. Here, we report that DDX60 is a sentinel for both RIG-I activation and viral RNA degradation. We show that DDX60 is an upstream factor of RIG-I that activates RIG-I signaling in a ligand-specific manner. DDX60 knockout attenuates RIG-I signaling and significantly reduces virus-induced type I IFN production in vivo. In addition, we show that DDX60 is involved in RIG-I-independent viral RNA degradation. DDX60 and RIG-I adaptor MAVS double-knockout mice reveal a role for DDX60-dependent RNA degradation in antiviral responses. Several viruses induced DDX60 phosphorylation via epidermal growth factor receptor (EGFR), leading to attenuation of the DDX60 antiviral activities. Our results define DDX60 as a sentinel for cytoplasmic antiviral response, which is counteracted by virus-mediated EGF receptor activation., (Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.)

In recent years, various molecular target agents have been investigated for gastric cancer. VEGF is one of the most potent angiogenic factors and is a signaling molecule secreted by many solid tumors. High VEGF expression is one of the characteristic features of gastric carcinomas, thus targeting VEGF is considered a promising strategy for gastric cancer. Ramucirumab, an anti-VEGF receptor antibody, has proven to be effective for previously treated advanced gastric cancer. Details of ramucirumab, including two pivotal Phase III studies, will be discussed in this review. Ramucirumab, with or without chemotherapy, improved survival in gastric cancer after previous systemic chemotherapy, thus becoming the standard of care for this patient population. Optimal timing of ramucirumab use and adequate biomarkers for patient selection as well as mechanism of resistance should be explored in future research.

Introduction: Bladder cancer represents 7% of all new cancers diagnosed in the USA in 2015. Furthermore, the mortality of metastatic bladder cancer has not decreased substantially in the last four decades. Angiogenesis is known to play a major role in the pathogenesis of bladder cancer., Areas Covered: The following article provides an overview of the first results of agents targeting the VEGF pathway in the treatment of metastatic bladder cancer., Expert Opinion: Despite a few clinical trials providing preliminary encouraging results, the overall outcomes of the first published trials have been rather disappointing. In some instances, especially the case of trials which have investigated the use of new targeted agents as a single agent, no significant improvement in outcomes was seen, or was not sustained. In other cases, such as with combination trials, intolerable adverse effects have compromised the trials, due to overlapping toxicity between the targeted agent and chemotherapeutic agent(s). Further trials are warranted possibly combining different targeted agents or the use of sequential therapy. A better selection of the patient population may also be a key factor to improve patient outcomes, as many predictive factors of response seem to have already been identified.

Angiogenesis is a vital process in the progression and metastasis of solids tumors including gastric adenocarcinoma. Tumors induce angiogenesis by secreting proangiogenic molecules such as vascular endothelial growth factor A (VEGF-A), and VEGF-A inhibition has become a common therapeutic strategy for many cancers. Several drugs targeting the VEGF-A pathway have been approved for clinical use in selected solid tumors, and several anti-VEGF-A strategies have been examined for gastric cancer. Phase II studies suggested that bevacizumab, an anti-VEGF antibody, can increase the efficacy of chemotherapy for advanced gastric cancer, but two international phase III trials failed to show an overall survival benefit. Two more recent international phase III trials have examined ramucirumab, an antibody targeting the primary receptor for VEGF-A, as second-line therapy for advanced gastric cancer and found a survival benefit both as single agent therapy and when combined with chemotherapy. Finally, correlative science studies suggest that the VEGF-A pathway may have varying importance in gastric cancer progression depending on ethnicity or race. This article will review the preclinical and clinical studies on the role of the VEGF-A pathway inhibition in gastric cancer.

In addition to eradication of Helicobacter pylori, chemotherapy with anticancer agents, and radiation therapy, the treatment with molecular target drugs including rituximab, a CD20 antagonist, is one of the promising new regimens. The mucosa-associated lymphoid tissue (MALT) lymphoma is histologically characterized by rich distribution of the microvascular network consisting of the immature capillaries, lymphatics and venules, and this microvascular network could be the target of the new pharmacotherapy in addition to the direct action on the accumulated B lymphocytes. We have established the animal model of the gastric MALT lymphoma by the Helicobacter heilmannii (H. heilmannii) peroral infection of C57BL/6 mice. The disease induced by this model is very similar to the human counterpart, because of the lymphoepithelial lesion characteristic of the human MALT lymphoma as well as the rich vascularization and localization of vascular endothelial growth factor (VEGF) and its receptors, Flt-1, Flk-1 and Flt-4. By administering VEGF receptor antibodies or celecoxib, one of the cyclooxygenase 2 inhibitors, we were able to induce a significant decrease in the size of the tumor and the apoptotic changes of the endothelial cells of the microvascular network. These antiangiogenic strategies were suggested to be candidates for the new pharmacological treatment of gastric MALT lymphoma, when other treatments are not effective.

Angiogenesis and lymphangiogenesis are distinct and complex processes requiring a finely tuned balance between stimulatory and inhibitory signals. Immune and inflammatory cells can contribute to these processes by multiple mechanisms: directly by producing a broad array of angiogenic growth factors, and indirectly by secreting several cytokines, chemokines and other mediators able to coordinate the cell-cell interactions. Immune cells can stimulate or inhibit angiogenesis/lymphangiogenesis, depending on their activation status and subset specificity. We summarize recent findings reporting the expression and activity of angiogenic and lymphangiogenic factors and their receptors and coreceptors in immune cells. It is evident that modulation of angiogenesis and lymphangiogenesis by the innate and adaptive immune cells (mast cells, macrophages, dendritic cells, basophils, eosinophils, and some subsets of T cells) is a highly complex process not yet completely understood., (Copyright © 2014 S. Karger AG, Basel.)

Background: Urea injection has been used in hemangioma treatment as sclerotherapy. It shrinks vascular endothelial cells and induces degeneration, necrosis, and fibrosis. However, this treatment still has disadvantages, such as lacking targeting and difficulty in controlling the urea dosage. Thus, we designed a urea immunoliposome to improve the efficiency of treatment., Methods: The urea liposome was prepared by reverse phase evaporation. Furthermore, the urea immunoliposome was generated by coupling the urea liposome with a vascular endothelial growth factor receptor (VEGFR) monoclonal antibody using the glutaraldehyde cross-linking method. The influence of the urea immunoliposome on cultured human hemangioma vascular endothelial cells was observed preliminarily., Results: Urea immunoliposomes showed typical liposome morphology under a transmission electron microscope, with an encapsulation percentage of 54.4% and a coupling rate of 36.84% for anti-VEGFR. Treatment with the urea immunoliposome significantly inhibited the proliferation of hemangioma vascular endothelial cells (HVECs) in a time- and dose-dependent manner., Conclusions: The urea immunoliposome that we developed distinctly and persistently inhibited the proliferation of HVECs and is expected to be used in clinical hemangioma treatment.

We have previously reported the isolation of a novel single-chain variable fragment (scFv) against vascular endothelial growth factor (VEGF), from a phage-displayed human antibody repertoire. This scFv, denominated 2H1, was shown to block the binding of VEGF to its receptor but exhibited a moderate binding affinity. Here, we describe the affinity maturation of the 2H1 scFv. Two phage-displayed libraries were constructed by diversification of the third complementarity-determining regions (CDRs) of the light (VL) and heavy (VH) chain variable domains of 2H1 using parsimonious mutagenesis. A competitive phage-selection strategy in the presence of the parental scFv as a competitor was used to eliminate low affinity binders. High affinity variants were retrieved from both libraries. An optimized VL variant was designed and constructed by combining recurrent replacements found among selected variants in a single molecule, resulting in an additional affinity increase. Further affinity improvements were achieved by combining this optimized VL with the best VH variants. The final variant obtained here, L3H6, showed an overall affinity improvement of 18-fold over the parental scFv and exhibited an enhanced potency to block the binding of VEGF to its receptor. Using phage display and extensive mutagenesis of VEGF, we determined the fine specificity of L3H6. This functional mapping revealed a novel neutralizing epitope on human VEGF defined by the residues Y25, T71, E72, N100, K101, E103 and R105. The conformational epitope recognized by L3H6 was recapitulated by grafting human VEGF residues into the mouse molecule, providing further confirmation of the nature of the identified epitope.

Peripheral nerve injury is a major neurological disorder that can cause severe motor and sensory dysfunction. Neurogenic effects of vascular endothelial growth factor (VEGF) have been found in the central nervous system, and we examined whether VEGF could promote anatomical and functional recovery of peripheral nerves after injury using an avascular corneal nerve injury model. We found that VEGF enhanced neurite elongation in isolated trigeminal ganglion neurons in a dose-dependent manner. This effect was suppressed by neutralizing antibodies for VEGF receptor (VEGFR) 1 and 2 or neuropilin receptor 1 or by VEGFR2 inhibitors (SU 1498 and Ki 8751). In vivo, mice receiving sustained VEGF via implanted pellets showed increased corneal nerve regeneration after superficial injury compared with those receiving vehicle. VEGF injected subconjunctivally at the time of injury accelerated reinnervation, the recovery of mechanosensation, and epithelial wound healing. Endogenous VEGF expression was up-regulated in the corneal epithelium and stroma after wounding. Thus, VEGF can mediate peripheral neuron growth but requires the activation of multiple VEGF receptor types. In addition, VEGF can accelerate the return of sensory and trophic functions of damaged peripheral nerves. Wounding induces the expression of VEFG, which may modulate physiological nerve repair.

Inhibiting angiogenesis has become an important therapeutic strategy for cancer treatment but, like other current targeted therapies, benefits experienced for late-stage cancers can be curtailed by inherent refractoriness or by acquired drug resistance, requiring a need for better mechanistic understanding of such effects. Numerous preclinical studies have demonstrated that VEGF pathway inhibitors suppress primary tumour growth and metastasis. However, it has been recently reported that short-term VEGF and VEGFR inhibition can paradoxically accelerate tumour invasiveness and metastasis in certain models. Here we comprehensively compare the effects of both antibody and small molecule receptor tyrosine kinase (RTK) inhibitors targeting the VEGF-VEGFR pathway, using short-term therapy in various mouse models of metastasis. Our findings demonstrate that antibody inhibition of VEGF pathway molecules does not promote metastasis, in contrast to selected small molecule RTK inhibitors at elevated-therapeutic drug dosages. In particular, a multi-targeted RTK inhibitor, sunitinib, which most profoundly potentiated metastasis, also increased lung vascular permeability and promoted tumour cell extravasation. Mechanistically, sunitinib, but not anti-VEGF treatment, attenuated endothelial barrier function in culture and caused a global inhibition of protein tyrosine phosphorylation, including molecules important for maintaining endothelial cell-cell junctions. Together these findings indicate that, rather than a specific consequence of inhibiting the VEGF signalling pathway, pharmacological inhibitors of the VEGF pathway can have dose- and drug class-dependent side-effects on the host vasculature. These findings also advocate for the continued identification of mechanisms of resistance to anti-angiogenics and for therapy development to overcome it., (Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.)

Secondary lymphedema in humans is a common consequence of axillary lymph node dissection (ALND) to treat breast cancer. It is commonly hypothesized that lymphatic growth is required to increase fluid drainage and ameliorate lymphedema. Although there is a pronounced alteration in the balance of interstitial forces regulating fluid transport that sustains the chronic form of lymphedema, it is presently unknown whether changes occur to the balance of interstitial forces during acute lymphedema that may play a role in the recovery of fluid drainage. Here, we compared the relative importance of lymphangiogenesis of lymphatic vessels and interstitial flows for restoring fluid drainage and resolving acute lymphedema in the mouse foreleg after ALND. We found that removal of the axillary lymph nodes reduced lymph drainage in the foreleg at days 0 and 5 postsurgery, with fluid tracer spreading interstitially through subcutaneous tissues. Interstitial fluid drainage returned to normal by day 10, whereas functional regrowth of lymphatic vessels was first detected by indocyanine green fluorescence lymphography at day 15, demonstrating that the recovery of interstitial fluid drainage preceded the regrowth of lymphatic vessels. This was confirmed by the administration of VEGF receptor-3-neutralizing antibodies, which completely blocks lymphatic regrowth. It was found that the recovery of interstitial fluid drainage and the natural resolution of acute lymphedema produced by ALND were not hindered by VEGF receptor-3 neutralization, demonstrating that interstitial fluid drainage recovery and the resolution of acute lymphedema are lymphangiogenesis independent. The data highlight the central role of the interstitial environment in adapting to lymphatic injury to increase fluid drainage.

Age-related differences in thymic function influence the rapidity of T cell reconstitution following hematopoietic stem cell transplantation (HSCT). In adults, thymic reconstitution is delayed until after marrow engraftment is established, and is significantly improved by approaches that increase marrow chimerism, such as pretransplantation irradiation. In contrast, we show that neonatal mice undergo more rapid and efficient thymic reconstitution than adults, even when bone marrow (BM) engraftment is minimal and in the absence of pretransplantation radiation. We have previously shown that the neonatal thymus produces high levels of vascular endothelial growth factor (VEGF) that drives angiogenesis locally. In this report, we show that inhibition of VEGF prior to HSCT prevents rapid thymic reconstitution in neonates, but has no effect on thymic reconstitution in adults. These data suggest that the early radiation-independent thymic reconstitution unique to the neonatal host is mediated through VEGF, and reveals a novel pathway that might be targeted to improve immune reconstitution post-HSCT., (Copyright © 2012 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Aim: Spinal epidural fibrosis is an inherent result of surgical trauma after laminectomy. The conditions in which epidural fibrosis is excessive are in the etiology of failed back syndrome. There have been many attempts to prevent formation of epidural fibrosis. Bevacizumab which is an anti-angiogenic medication, inhibits the effect of VEGF and thereby decreases the new blood vessel formation and as a result prevents adhesions. This study shows the effect of bevacizumab on spinal epidural fibrosis developing after laminectomy in rats., Material and Methods: In this study, 20 Wistar rats were used. Rats were divided into two groups; a control group, and a bevacizumab group. Three-level laminectomy was performed on the rats. Rats in the control group only had the laminectomy. In the bevacizumab group, 2.5 mg/kg bevacizumab diluted in 0.9% NaCl with a factor of 1:10 impregnated on cotton was applied on the dura topically for 5 minutes. Three weeks later, rats were sacrificed for histopathologic examination. Epidural fibrosis tissue was graded following sacrifice., Results: Statistically, it was found that the bevacizumab group had significantly less epidural fibrosis compared to the control group (p < 0.05)., Conclusion: Bevacizumab reduced the spinal epidural fibrosis significantly that developed in rats after laminectomy via its anti-VEGF effect by blocking VEGF receptors.

Introduction: The interaction between the VEGFRs and their ligands plays an important role in tumor angiogenesis. Despite a series of problems encountered during early work on blocking growth factors, current evidence injects further vigor into researching the modulation of VEGFR activity. Emerging preclinical and clinical studies suggest that attenuating receptor activity can synergistically promote antitumor action if utilized concurrently with conventional therapies., Areas Covered: This review presents an up-to-date assessment of the potential role of modulating receptor activities in various cancers. The sentinel work on the proof of principles in various animal models, and the current translational research on these small molecule inhibitors and receptor blocking antibodies, from Phase I to Phase III trials, has been systematically examined with an emphasis on agents in earlier stages of development., Expert Opinion: Many clinical trials are ongoing, but early phase trials show promising results. Recently, there has been a huge explosion of research activity either in the development of new drugs or in the understanding its biology. Many current trials lend support to the rationale behind these therapies, which can function as adjuvants to conventional treatments. It has been argued that normalization of tumor-induced vasculature can promote better drug delivery and prevent resistance to radiotherapy. However, strategies involving the inhibition of the interaction of VEGFRs with ligands and their downstream pathways are not, in general, at a stage where it will be directly useful in clinical cancer treatment. A deeper understanding of these biologic therapies will help to improve the efficacy of conventional treatments and furthermore reduce dose-dependent cytotoxic activity.

Bullous keratopathy (BK) is a chronic corneal edema with or without subepithelial bullae as a result of a loss of the endothelial cells. 15 patients with BK after cataract surgery with intraocular lens implantation, due to Fuchs dystrophy (n = 3) or corneal endothelial trauma (n = 12) were included in the study. All patients were treated by amniotic membrane transplantation (AMT). Corneal epithelial cells in patients suffering from BK secreted 3.91 +/- 3.09 pg/mL of IL-1 alpha, 4446 +/- 16.8 pg/mL of TNF and 81.43 +/- 37.81 pg/mL of VEGF-I. Levels of all 3 investigated cytokines were significantly higher as compared to controls (p < 0.005). Amniotic membranes that were used to treat investigated patients contained 638.98 +/- 613.98 pg/mL of IL-1ra, 0.026 +/- 0.009 pg/mL of sTNF and 81.39 +/- 21.01 pg/mL of VEGF-R. Beneficial clinical effect of the AMT in treating BK could be explained by its natural production of pro-inflammatory cytokine antagonists such as IL-ra, sTNF antagonist and VEGF-R.

Amniotic membrane transplantation (AMT) leads to reduction of inflammatory symptoms and causes faster epithelisation in corneal ulcers and persistant epithelial defect. 21 patients with corneal ulcer (n = 18) or non-healing epithelial defect (n = 3) unresponsive to conventional treatment were included in the study. All patients were treated by AMT. Corneal epithelial cells in patients suffering from corneal ulcer secreted 3.51 +/- 1.79 of IL-1alpha, 64.27 +/- 31.53 pg/mL of TNFalpha and 209.07 +/- 201.82 pg/mL of VEGF. Levels of all 3 investigated cytokines were significantly higher as compared to controls (p < 0.005). Amniotic membranes that were used contained 775.69 +/- 613.98 pg/mL of IL-1alpha, 0.036 +/- 0.033 pg/mL of sTNF and 175.01 +/- 166.63 pg/mL of VEGF-R. Supporting effect of the AMT could be explained by the fact that AM secretes its natural antinflammatory antagonists IL-1ra, sTNF and VEGF-R.

Evidence suggests that signalling through lipopolysaccharide (LPS) has a significant role in the development of gastrointestinal malignancies. We previously demonstrated the critical role of myeloid differentiation (MD)-2, the essential co-receptor of LPS, for induction of cyclooxygenase (Cox)-2 in intestinal epithelial cells. Cyclooxigenase-2 was suggested to play a key role in colorectal cancer through the effects of prostaglandin (PG) E(2) generated. We, therefore, addressed the role of MD-2 in several parameters related to malignancy, namely cell proliferation and migration, using colon cancer cells (HT-29). We found that overexpression of MD-2 confers a significantly greater proliferation and migration capacity to these cells. MD-2-dependent proliferation and migration appeared independent of Cox-2 activity but was reduced by endothelial growth factor receptor (EGFR) neutralizing antibodies as well as by pharmacological inhibition of EGFR tyrosine phosphorylation. We propose that MD-2 overexpression contributes to tumour aggressiveness via a Cox-2-independent excessive EGFR signalling. Moreover, MD-2 expression levels were higher in tissue from patients with colorectal cancer as compared with paired control colorectal mucosa. Our data attest to a role of MD-2 activity in colon cancer epithelial cell proliferation and migration, which may be important in the general correlation between innate immune response, chronic inflammation, and cancer.

During the last decades, several improvements in treating gynecological malignancies have been achieved. In particular, target therapies, mostly monoclonal antibodies, have emerged as an attractive option for the treatment of these malignancies. In fact, various molecular-targeted agents have been developed for a variety of malignancies with the objective to interfere with a precise tumor associated receptor, essential for cancer cell survival or proliferation, blocking its function, of the cancer cells. Alternatively, monoclonal antibodies have been developed to block immune suppression or enhance functions of immune effector cells. So far, several monoclonal antibodies have been tested for clinical efficacy for the treatment of gynecological cancers. Antibodies against Vascular Endothelial Growth Factor (VEGF) and Epidermal Growth Factor Receptor (EGFR) have been used in different neoplasms such as ovarian and cervical cancer. Catumazumab, a bivalent antibody against CD3 and EpCAM, is effective in the treatment of neoplastic ascites. Other antibodies are peculiar for specific cancer-associated antigen such as Oregovomab against CA125 or Farletuzumab against the folate receptor. Here we describe the preclinical and clinical experience gained up to now with monoclonal antibodies in tumors of the female genital tract and trace future therapeutic and research venues.

Over the past decade, a multitude of targeted agents have been explored in the treatment of advanced non-small cell lung cancer (NSCLC). Thus far, two broad classes of agents have been implemented in clinical practice: (a) vascular endothelial growth factor (VEGF)-directed therapies and (b) antagonists of the epidermal growth factor receptor (EGFR). In the former category, the agent bevacizumab (a monoclonal antibody) has shown landmark improvements in survival when added to cytotoxic therapy. Small molecule tyrosine kinase inhibitors (TKI) targeting the VEGF receptor (i.e., sunitinib, sorafenib, and vandetanib) show activity in phase II clinical studies. With respect to EGFR-directed therapies, the TKIs gefitinib and erlotinib have shown significant benefit, and have uncovered valuable information about the biology of lung cancer. Outside of therapies directed specifically at VEGF- and EGFR-mediated signaling, trials evaluating insulin-like growth factor-1 receptor (IGF-IR)-targeting agents, cyclooxygenase-2 (COX-2) inhibitors, c-met inhibitors, irreversible pan-HER inhibitors, mammalian target of rapamycin (mTOR) inhibitors, and histone deacetylase (HDAC) inhibitors are ongoing. Inhibitors of ALK show great promise in patients with the relevant gene translocation. Herein, the clinical development of novel therapies for NSCLC is described, including some discussion of relevant biomarkers and determination of synergy with both cytotoxic therapy and other targeted agents., ((c)2010 AACR.)

Purpose: A new VEGF receptor fusion protein FP3 was shown to have promising antitumor potency better than Bevacizumab. Characterization of its immune response is essential to the safe and effective administration in clinical trials. In this study, both BIACORE and ELISA assays were employed to assess pre-clinical immunogenicity of FP3 in monkeys., Experimental Design: Serum samples from 20 rhesus monkeys were analyzed for the generation of anti-FP3 antibody after intravenous administration of three doses of FP3 (n = 6 per group) or buffer control (n = 2). Sera samples were obtained at 2, 4, 6, 8, 10 weeks after the first administration., Results: It showed BIACORE presented linear correlation with the dilution of anti-FP3 antibody and the results of ELISA. Two weeks after the initial FP3 injection, anti-FP3 antibody was detected in about 20% FP3-treated monkeys. The ratio of positive samples and the titer of antibody increased along with the FP3-treatment time. Six weeks following FP3 injection almost all the samples were anti-FP3 antibody positive. Moreover, the titer of anti-FP3 antibody but not the ratio of positive samples was also enhanced when the dose of FP3 was elevated. Furthermore, the immunoglobulin types and subclasses of anti-FP3 antibody serum components were mainly identified as IgG1 and IgG4, not IgM. Serum antibodies are characterized that they could not block FP3 binding to VEGF and were non-neutralizing., Conclusions: Our data implied that proteins with full human sequences may also have the potential to induce immune response in rhesus monkeys, and BIACORE could be an effective approach to detect the immunogenicity of protein therapeutics in clinic.

Targeted mAbs to VEGFR and EGFR are well-established therapies for the treatment of colorectal cancer. The costs and toxicities associated with these novel treatments are not insignificant, and therefore molecular markers that predict treatment efficacy are needed to individualize the therapy administered to each patient. Recent data in this research field support KRAS mutation testing to guide the selection of EGFR inhibitors for the treatment of colorectal cancer. This review discusses the evidence that KRAS mutation analysis can indicate a beneficial response to EGFR inhibitors, and the potential and limitations of other mutations in the VEGF and EGF signaling pathways as predictive molecular markers in this setting.

By using neutralizing monoclonal antibodies to vascular endothelial growth factor receptor type 1 (VEGFR1) and VEGFR2, we have shown that acute myelogenous leukemia (AML) cells with specific chromosome abnormalities are dependent on VEGF/VEGFR system. AML with t(8;21) is the most dependent subtype on VEGF with both VEGFR1 and VEGFR2. t(15;17)AML cells depend on VEGF with VEGFR1. AML cells with 11q23 abnormalities showed variable dependence on VEGF. The growth of t(11;19)AML cells are most extensively inhibited by anti-VEGFR1 antibody. Then, the growth of Kasumi-1, a t(8;21) cell line was suppressed by either anti-VEGFR1 antibody (p=0.0022) or anti-VEGFR2 antibody (p=0.0029) in a dose-dependent manner. The growth of NB4, a t(15;17) cell line was more potently suppressed by anti-VEGFR1 antibody (p=0.0111) than by anti-VEGFR2 antibody (p=0.0477). These results are quite concordant with the results of clinical samples with t(8;21) or t(15;17). In addition, anti-VEGFR2 monoclonal antibody significantly potentiated the growth inhibitory effect of idarubicin for Kasumi-1. As for downstream signals, we have shown that VEGFR2 transduce growth and survival signals through phosphorylation of Akt and MEK in leukemia cells (Kasumi-1). However, VEGFR1 transduce growth and survival signals through pathways other than MEK and Akt (NB4), although Akt phosphorylation may account for some of the VEGFR1 signals (Kasumi-1). Finally, our data suggested that autocrine pathway of VEGF and VEGFRs observed in AML cells with specific chromosomal translocations have contributed to leukemogenesis as activated signaling of receptor tyrosine kinase.

Targeted therapies with monoclonal antibodies have been shown to improve the outcome of non-small cell lung cancer (NSCLC). Current strategies focus on the blockade of growth factor receptors and the inhibition of angiogenesis. Epidermal growth factor receptor (EGFR)-directed monoclonal antibodies in combination with platinum-based first-line chemotherapy have shown promising efficacy in phase II trials. In a phase III trial, cetuximab combined with cisplatin/ vinorelbine resulted in superior survival compared to chemotherapy alone in patients with advanced EGFR-positive NSCLC. Inhibition of angiogenesis has also been successfully applied as a new treatment strategy. Bevacizumab added to palliative chemotherapy has improved progression-free survival in two phase III trials and overall survival in one of these trials in selected patients with advanced non-squamous cell lung cancer. Bevacizumab is now approved for selected patients with advanced NSCLC in combination with platinum-based chemotherapy. Figitumumab is a monoclonal antibody against the insulin-like growth factor-1 receptor (IGF-1R) which demonstrated activity in preclinical models of NSCLC and in a phase II trial. Because of these promising results, three randomized, open-label, international phase III trials of figitumumab in patients with locally advanced or metastatic NSCLC are in progress.

We are performing a phase I clinical trial of combination-therapy with gemcitabine and epitope peptide derived from human vascular endothelial growth factor receptor (VEGFR) for advanced pancreas cancer. The aim of this study was to evaluate the safety, immunological response and tumor response. Six patients have been enrolled at present. During the clinical course, no major adverse events were observed. Additionally, two out of 6 cases showed a minor shrinkage of the tumor. Immunological response has not been analyzed yet. These results indicated that a combination-therapy with gemcitabine and epitope peptides derived from VEGFR could be tolerable.

Objective: To analyze immunohistochemically the localization of the VEGF receptors in experimental intervertebral disc degeneration tissues in a pig model., Materials and Methods: In six domestic pigs, the cranial bony endplate of the L4 vertebra were perforated into the nucleus pulposus. Three months postoperatively, the animals were sacrificed and the experimental and control vertebrae, complete with intervertebral discs, were excised and subjected for immunohistochemical staining of vascular endothelial growth factor receptors (VEGFR) along with VEGF - A, -C, -D and blood and lymphatic vessel markers vWF and LYVE-1., Results: The results of immunohistochemical analysis of experimental samples showed VEGFR-1 (Flt-1) expression in intervertebral disc and all paradiscal tissues studied. In control samples expression of VEGFR-1 was lower and absent in the intervertebral discs. Comparatively less of VEGFR-2 (KDR/Flk-1) and VEGFR-3 (Flt-4) than VEGFR-1was found in degenerated intervertebral discs and paradiscal tissues. In contiguous control intervertebral discs and control paradiscal tissues VEGFR-2 and-3 receptors were expressed to a lower extent than in experimental tissues or were even totally absent. Also growth factors VEGF-A, -C, -D, as well as von Willebrand factor and to a much lower extent LYVE-1 were differently expressed in experimental and control intervertebral discs., Conclusion: In experimental intervertebral disc degeneration, VEGF receptors were expressed in the damaged disc and paradiscal tissues. In the same tissues, VEGF-A, -C, and -D, signs of blood and lymphatic vessel in-growth and reactive/adaptive vertebral bone remodelling were found.

Vascular endothelial growth factor (VEGF) signals on vascular and hematopoietic cells via its receptors, VEGFR-2 (KDR) and VEGFR-1 (FLT-1). Elevated levels of VEGF, such as during tumor growth or inflammation, have been suggested to suppress hematopoiesis; most studies refer to KDR as the main receptor involved in this inhibitory effect. In the present study, having detected expression of FLT-1 in B-lymphoid precursors, we exploited the possibility that VEGF signaling via FLT-1 might affect early B-cell commitment. Using a well-established in vitro B-cell differentiation assay, we demonstrate that FLT-1 blockade promotes B-cell commitment and subsequent differentiation, while KDR blockade has no effect on B-cell commitment. In agreement, in vivo transplantation of human (CD34+) or murine (Sca1+l/Lin-) FLT-1-negative hematopoietic precursors into irradiated severe combined immune-deficient mice restored the bone marrow lymphoid compartment, while transplanting the FLT-1-positive counterpart failed to repopulate the lymphoid compartment, and unexpectedly resulted in early death of the irradiated recipients due to hematopoietic suppression. Taken together, we suggest that VEGF signaling via FLT-1 on hematopoietic precursors may restrict lymphopoiesis.

Targeted immunotherapy against tumors or angiogenesis has shown promise as an alternative approach for the treatment of malignant disease. Whether or not combining these two treatment modalities would enhance the antitumor effect was tested in mouse models of malignant melanoma. C57BL/6 mice bearing established subcutaneous B16 tumors were treated with anti-vascular endothelial growth factor receptor (anti-VEGFR) fetal liver kinase-1 (Flk-1) monoclonal antibody (mAb) DC101 and/or anti-TYRP-1/gp75 (tyrosinase-related protein-1) mAb TA99. The growth of subcutaneous B16 tumors was significantly suppressed by the mAb DC101 (63%, p<0.001) and by mAb TA99 (75%, p<0.001) treatment alone. The combined antibody (TA99+DC101) treatment resulted in a significant enhancement (93%, p<0.001) of tumor growth suppression. In a B16 pulmonary metastasis model, combined therapy with mAb DC101 and mAb TA99 resulted in a significant reduction of lung metastases compared to the control (p<0.001) and the single agent treatment groups (p<0.05). A combined modality approach that provides passive immunity to melanoma differentiation antigens as well as inhibiting tumor neovascularization may be valuable for the treatment of malignant melanoma.

Angiogenesis, the growth of new blood vessels from previously existing vasculature, is a requirement for tumor growth and metastasis. The first US FDA-approved drugs targeting angiogenesis have shown potential in the treatment of malignant gliomas. Immunotherapy as a treatment modality lends itself well to specifically targeting angiogenesis in tumors and may represent a powerful tool in the treatment of malignant gliomas. This review focuses on developments in immunotherapy targeting angiogenesis and tumor-vascular-specific endothelial cells using a variety of immunotherapeutic strategies including monoclonal antibodies and conjugated immunotoxins, as well as cellular, peptide, DNA and dendritic cell vaccines.

Head and neck cancer (HNC) is the fifth most common cancer in the world. In the US alone, HNC accounts for 3-5% of all malignancies annually. Squamous cell carcinoma arising from the mucosa of the upper aerodigestive tract is the most common type of HNC and accounts for 90% of HNC diagnoses. Despite continued advances in the therapeutic options, the disease-free survival, functional outcome, toxicity of therapy and overall survival have remained less than optimal for patients with locally advanced, recurrent or metastatic disease. Therefore, new approaches for the treatment of patients with HNC, particularly patients with advanced stage, are clearly needed. Among the new therapies, molecular-targeted and biological therapies have gained special attention. While clinical trial data support the use of epidermal growth factor receptor (EGFR) inhibition in metastatic and locally advanced HNC, numerous trials are seeking to establish a clear role for new therapies targeting EGFR, the receptor for the type I insulin-like growth factor, as well as anti-angiogenesis agents.

Rationale: Severe pulmonary arterial hypertension (SPH) is a frequently lethal condition characterized by pulmonary vascular remodeling and right heart strain or failure. SPH is also often associated with autoimmune and collagen vascular disorders., Objectives: To study the effects of T cells on the development of experimental SPH., Methods: Athymic nude rats lacking T cells were treated with a single subcutaneous injection of vascular endothelial growth factor (VEGF) receptor blocker SU5416 (20 mg/kg) to induce pulmonary vascular endothelial cell apoptosis. Immunohistochemical analysis and IL-4 levels of the lung tissue were performed. Cell death and proliferation were assessed by Western blot and immunohistochemistry., Measurements and Main Results: In contrast to SU5416-treated euthymic rats that develop SPH only in combination with chronic hypoxia, athymic nude rats developed SPH and vascular remodeling (similar to clinical SPH) at normoxic conditions as demonstrated by measurements of pulmonary artery pressure and right ventricle hypertrophy. Pulmonary arterioles became occluded with proliferating endothelial cells and were surrounded by mast cells, B cells, and macrophages. IL-4, proliferating cell nuclear antigen, and collagen type I levels were markedly increased in SU5416-treated athymic rat lungs. Antibody deposition was noted along the vascular endothelium in rats with SPH. Finally, protection from SPH was conferred by immune challenge with spleen cells from euthymic nude rats., Conclusions: These studies demonstrate the importance of a complete, intact immune system in protecting against pulmonary angioproliferation in this new model of SPH as well as the importance of intact VEGF receptor signaling for lung endothelial cell homeostasis.

The prognosis in advanced non-small cell cancer (NSCLC) remains poor despite the introduction of several new cytotoxic drugs in the past decade. New approaches are required, and an improved understanding of lung cancer biology is identifying molecular mechanisms that are potential targets for novel therapies. Antagonists of signalling via the erbB and VEGFR families of transmembrane receptors have promising activity in NSCLC, and survival benefit has already been demonstrated for both erlotinib and bevacizumab. Although some patients enjoy dramatic and sustained responses to some of the new targeted drugs, overall response rates in unselected NSCLC patient groups are modest. This reflects the molecular heterogeneity of the disease; further clinical progress will require improved patient selection for treatment with both novel agents and established chemotherapy drugs. Here, we review recent advances in NSCLC biology likely to provide insight into such selection strategies.

Metastatic renal cell carcinoma (RCC) is resistant to conventional chemotherapy. Combined data for a variety of immunotherapies resulted in an overall chance of partial (PR) or complete remission (CR) of only 12.9%. There is a clear need for novel, more effective therapies to prevent relapse, control metastases and improve overall survival. Improved understanding of RCC disease biology has led to the introduction of molecularly targeted treatment strategies in these cancers. Von Hippel-Lindau (VHL) gene inactivation is observed in most clear cell renal carcinoma, resulting in vascular endothelial growth factor (VEGF) over-expression and driving the malignant phenotype. This review discusses the efficacy of novel therapies targeting the VEGF receptor (VEGFR) (e.g. anti-VEGF antibodies, VEGFR tyrosine kinase inhibitors, mTOR inhibitors), some of which were recently approved by the Food and Drug Administration/European Medicines Evaluation Agency (FDA/EMEA) and represent the new treatment standards in RCC patients.

Angiogenesis is a multistep complex phenomenon critical for several inflammatory and neoplastic disorders. Basophils, normally confined to peripheral blood, can infiltrate the sites of chronic inflammation. In an attempt to obtain insights into the mechanism(s) underlying human basophil chemotaxis and its role in inflammation, we have characterized the expression and function of vascular endothelial growth factors (VEGFs) and their receptors in these cells. Basophils express mRNA for three isoforms of VEGF-A (121, 165, and 189) and two isoforms of VEGF-B (167 and 186). Peripheral blood and basophils in nasal polyps contain VEGF-A localized in secretory granules. The concentration of VEGF-A in basophils was 144.4 +/- 10.8 pg/10(6) cells. Immunologic activation of basophils induced the release of VEGF-A. VEGF-A (10-500 ng/ml) induced basophil chemotaxis. Supernatants of activated basophils induced an angiogenic response in the chick embryo chorioallantoic membrane that was inhibited by an anti-VEGF-A Ab. The tyrosine kinase VEGFR-2 (VEGFR-2/KDR) mRNA was expressed in basophils. These cells also expressed mRNA for the soluble form of VEGFR-1 and neuropilin (NRP)1 and NRP2. Flow cytometric analysis indicated that basophils express epitopes recognized by mAbs against the extracellular domains of VEGFR-2, NRP1, and NRP2. Our data suggest that basophils could play a role in angiogenesis and inflammation through the expression of several forms of VEGF and their receptors.

The alveolar destruction leading to airspace enlargement in patients with end-stage chronic obstructive pulmonary disease (COPD) is frequently progressive, despite smoking cessation. Several laboratories have accumulated data demonstrating the presence of immune cells in bronchial biopsy specimens and lung tissue sections from patients with COPD. Recently, the accumulation of T and B lymphocytes, often forming follicles, in the lung parenchyma from patients with severe COPD has been reported. In addition, it has been postulated that there might be an autoimmune component to COPD. T-cell receptor analysis has provided data consistent with the concept of T-cell clones in the lung tissue from patients with COPD. Against this background, we developed a model of autoimmune emphysema in adult rats. Based on published data showing that immunization of mice with human umbilical vein endothelial cells (HUVECs) causes production of anti-vascular endothelial growth factor (VEGF) receptor II (KDR) antibodies, and our own data indicating that administration of a VEGF receptor blocker in adult rats causes emphysema, we reasoned that intraperitoneal injection of HUVECs in rats would generate both anti-VEGF receptor antibodies and emphysema. Indeed, intraperitoneal injection of HUVECs caused emphysema. We further explored the autoimmune nature of this model, identified KDR antibodies in the serum of HUVEC-immunized rats, and injected serum from the emphysematous rats into naive rats and mice, which resulted in emphysema. Presently, we are in the process of investigating whether cigarette smoke extract causes emphysema. We recently identified anti-endothelial cell antibodies in the serum of patients with end-stage emphysema.