Update on angiogenesis inhibitors

Pediatric Chemotherapy Drugs Associated With Cardiotoxicity

Pediatric cancers are a common cause of childhood morbidity. As a result, chemotherapeutic regimens have been designed to target childhood cancers. These medications are necessary to treat pediatric cancers, however, oncology management options are accompanied by multiple negative and potentially fatal adverse effects. Although anthracyclines are the most commonly used chemotherapeutic agents associated with cardiotoxicity, we also explore other chemotherapeutic drugs used in children that can potentially affect the heart. Genetic variations resulting in single nucleotide polymorphism (SNP) have the propensity to modify the cardiotoxic effects of the chemotherapy drugs. The clinical presentation of the cardiac effects can vary from arrhythmias and heart failure to completely asymptomatic. A range of imaging studies and laboratory investigations can protect the heart from severe outcomes. The physiology of the heart and the effect of drugs in children vary vividly from adults; therefore, it is crucial to study the cardiotoxic effect of chemotherapy drugs in the pediatric population. This review highlights the potential contributing factors for cardiotoxicity in the pediatric population and discusses the identification and management options.

Inhibiting Endothelial Cell Function in Normal and Tumor Angiogenesis Using BMP Type I Receptor Macrocyclic Kinase Inhibitors

Angiogenesis, i.e., the formation of new blood vessels from pre-existing endothelial cell (EC)-lined vessels, is critical for tissue development and also contributes to neovascularization-related diseases, such as cancer. Vascular endothelial growth factor (VEGF) and bone morphogenetic proteins (BMPs) are among many secreted cytokines that regulate EC function. While several pharmacological anti-angiogenic agents have reached the clinic, further improvement is needed to increase clinical efficacy and to overcome acquired therapy resistance. More insights into the functional consequences of targeting specific pathways that modulate blood vessel formation may lead to new therapeutic approaches. Here, we synthesized and identified two macrocyclic small molecular compounds termed OD16 and OD29 that inhibit BMP type I receptor (BMPRI)-induced SMAD1/5 phosphorylation and downstream gene expression in ECs. Of note, OD16 and OD29 demonstrated higher specificity against BMPRI activin receptor-like kinase 1/2 (ALK1/2) than the commonly used small molecule BMPRI kinase inhibitor LDN-193189. OD29, but not OD16, also potently inhibited VEGF-induced extracellular regulated kinase MAP kinase phosphorylation in ECs. In vitro, OD16 and OD29 exerted strong inhibition of BMP9 and VEGF-induced ECs migration, invasion and cord formation. Using Tg (fli:EGFP) zebrafish embryos, we found that OD16 and OD29 potently antagonized dorsal longitudinal anastomotic vessel (DLAV), intra segmental vessel (ISV), and subintestinal vessel (SIV) formation during embryonic development. Moreover, the MDA-MB-231 breast cancer cell-induced tumor angiogenesis in zebrafish embryos was significantly decreased by OD16 and OD29. Both macrocyclic compounds might provide a steppingstone for the development of novel anti-angiogenesis therapeutic agents.

Anti-Angiogenic Activity Of Bevacizumab-Bearing Dexamethasone-Loaded PLGA Nanoparticles For Potential Intravitreal Applications

Purpose

Age-related macular degeneration is a multifactorial disease involving inflammation and choroidal neovascularization. Vascular endothelial growth factor (VEGF) has been regarded as a potential therapeutic target to treat choroidal neovascularization. Dexamethasone can interfere with the expression or action of VEGF while bevacizumab targets and combines with VEGF. We propose electrostatically-conjugated bevacizumab-bearing dexamethasone-loaded poly (D,L-lactide-co-glycolide)/polyethylenimine nanoparticles (eBev-DPPNs) for angiogenic combination treatment of ocular diseases.

Methods

We prepared a novel nanoparticle composed of poly (D, L-lactide-co-glycolide) and polyethylenimine and loaded the nanoparticles with dexamethasone. Bevacizumab was adsorbed onto the surfaces of the nanoparticles by electrostatic interactions. The eBev-DPPNs were evaluated according to their size, polydispersity index, zeta potential, morphology, drug loading, release behavior, and stability. The structural stability of bevacizumab on the surface of the nanoparticles was also analyzed. Subsequently, angiogenesis was investigated in the presence of the eBev-DPPNs using cell apoptosis, wound healing, Transwell invasion, and tube formation assays on the human umbilical vein endothelial cells (HUVECs) in vitro and chick embryo chorioallantoic membrane assay in vivo. The eBev-DPPNs intravitreal injection was applied in the laser-induced rabbit choroidal neovascularization (CNV) model to confirm the role for potential intravitreal applications.

Results

The eBev-DPPNs was about 200 nm in diameter, with a narrow diameter distribution, and the surface charge was neutral (0.85 ± 0.37mV), which made the eBev-DPPNs stable under physiological conditions. The apoptosis, migration, invasion, and tube formation assays showed that the eBev-DPPNs had a good anti-angiogenic effect on HUVECs. The eBev-DPPNs also provided a strong inhibitory effect on VEGF secretion from HUVECs. Moreover, in vivo chick embryo chorioallantoic membrane assay showed eBev-DPPNs greatly reduced the amount of blood vessels. The leakage area of CNV decreased in the eBev-DPPNs group on rabbit CNV model.

Conclusion

The eBev-DPPNs are a promising novel anti-angiogenesis therapeutic for potential intravitreal applications such as age-related macular degeneration.

Pharmacogenetics of Chemotherapy-Induced Cardiotoxicity

PURPOSE OF REVIEW

The goal of this review is to summarize current understanding of pharmacogenetics and pharmacogenomics in chemotherapy-induced cardiotoxicity.

RECENT FINDINGS

Most of the studies rely on in vitro cytotoxic assays. There have been several smaller scale candidate gene approaches and a handful of genome-wide studies linking genetic variation to susceptibility to chemotherapy-induced cardiotoxicity. Currently, pharmacogenomic testing of all childhood cancer patients with an indication for doxorubicin or daunorubicin therapy for RARG rs2229774, SLC28A3 rs7853758, and UGT1A6*4 rs17863783 variants is recommended. There is no recommendation regarding testing in adults. There is clear evidence pointing to the role of pharmacogenetics and pharmacogenomics in cardiotoxicity susceptibility to chemotherapeutic agents. Larger scale studies are needed to further identify susceptibility markers and to develop pharmacogenomics-based risk profiling to improve quality of life and life expectancy in cancer survivors.

Blood coagulation parameters after intravitreal injection of aflibercept in patients with neovascular age-related macular degeneration

PURPOSE

The aim of this study was to evaluate the effect of intravitreal injection of aflibercept (IVA) on blood coagulation tests in neovascular age-related macular degeneration (AMD) patients.

METHODS

Thirty-four patients with neovascular AMD (study group) and 32 healthy individuals (control group) were enrolled. Prothrombin time (PT) and activated partial thromboplastin time (aPTT) were measured at different times in patients with neovascular AMD.

RESULTS

The levels of PT and aPTT after IVA were decreased at 1 month after the first injection and 1 month after the second injection compared to the baseline measurement in the study group.

CONCLUSIONS

IVA may cause a decrease in the levels of PT and aPTT at 1 month after the first injection and 1 month after the second injection although these results are not statistically significant in our study.

Daphnetin inhibits TNF-α and VEGF-induced angiogenesis through inhibition of the IKKs/IκBα/NF-κB, Src/FAK/ERK1/2 and Akt signalling pathways

Coumarins, identified as plant secondary metabolites possess diverse biological activities including anti-angiogenic properties. Daphnetin (DAP), a plant derived dihydroxylated derivative of coumarin has shown significant pharmacological properties such as anticancer, anti-arthritic and anti-inflammatory. The present study was performed to investigate the anti-angiogenic potential of DAP, focusing on the mechanism of action. The in vivo anti-angiogenic potential of DAP was evaluated by vascular endothelial growth factor (VEGF)-induced rat aortic ring (RAR) assay and chick chorioallantoic membrane (CAM) assay. For in vitro evaluation, wounding migration, transwell invasion, tube formation and apoptosis assays were performed on VEGF (8 ng/mL)-induced human umbilical vein endothelial cells (HUVECs). The cellular mechanism of DAP was examined on TNFα (10 ng/mL) and VEGF-induced HUVECs by extracting the mRNA and protein levels using RT-qPCR and western blotting. Our data demonstrated that DAP inhibited the in vivo angiogenesis in the RAR and CAM assay. DAP also inhibited the different steps of angiogenesis, such as migration, invasion, and tube formation in HUVECs. DAP inhibited nuclear factor-κB signalling together including TNF-α induced IκBα degradation; phosphorylation of IκB kinase (IKKα/β) and translocation of the NF-κB-p65 protein. Furthermore, western blotting revealed that DAP significantly down-regulated the VEGF-induced signalling such as c-Src, FAK, ERK1/2 and the related phosphorylation of protein kinase B (Akt) and VEGFR2 expressions. DAP reduced the elevated mRNA expression of iNOS, MMP2 and also, induced apoptosis in VEGF-stimulated HUVECs by the caspase-3 dependent pathway. Taken together, this study reveals that DAP may have novel prospective as a new multi-targeted medication for the anti-angiogenesis and cancer therapy.

Bevacizumab in Ovarian Cancer: State of the Art and Unanswered Questions

Ovarian cancer is a most lethal gynecologic tumor. The mainstay treatment is cytoreductive surgery followed by platinum-based chemotherapy. However, a high percentage of patients recur, thus needing multiple treatments with a frequently poor prognosis. In the last two decades, research has focused on the potential of target therapies to improve the survival of patients affected by ovarian cancer. Bevacizumab is one of the most studied target therapies, and it is approved for first- and second-line treatment of advanced epithelial ovarian, fallopian tube, and primary peritoneal tumors. Despite its widespread use with favorable results, controversy regarding patient selection and the best schedule, dosage, and timing of bevacizumab still exists. This review summarizes the state of the art on the use of bevacizumab for ovarian cancer in front-line, recurrence, and neoadjuvant settings. This study focuses on the results of pivotal trials, emerging data, ongoing research, and still unanswered questions about the most adequate dosage of bevacizumab and its potential activity after disease progression or rechallenge in previously treated patients.

Antiangiogenic activity of the lipophilic antimicrobial peptides from an endophytic bacterial strain isolated from red pepper leaf

The induction of angiogenesis is a crucial step in tumor progression, and therefore, efficient inhibition of angiogenesis is considered a powerful strategy for the treatment of cancer. In the present study, we report that the lipophilic antimicrobial peptides from EML-CAP3, a new endophytic bacterial strain isolated from red pepper leaf (Capsicum annuum L.), exhibit potent antiangiogenic activity both in vitro and in vivo. The newly obtained antimicrobial peptides effectively inhibited the proliferation of human umbilical vein endothelial cells at subtoxic doses. Furthermore, the peptides suppressed the in vitro characteristics of angiogenesis such as endothelial cell invasion and tube formation stimulated by vascular endothelial growth factor, as well as neovascularization of the chorioallantoic membrane of growing chick embryos in vivo without showing cytotoxicity. Notably, the angiostatic peptides blocked tumor cell-induced angiogenesis by suppressing the expression levels of hypoxia-inducible factor-1α and its target gene, vascular endothelial growth factor (VEGF). To our knowledge, our findings demonstrate for the first time that the antimicrobial peptides from EML-CAP3 possess antiangiogenic potential and may thus be used for the treatment of hypervascularized tumors.

Baicalin attenuates laser-induced choroidal neovascularization

PURPOSE

To determine whether intravitreally-injected baicalin inhibits the growth of choroidal neovascularization (CNV) experimentally induced via laser photocoagulation through analysis of angiogenic factors.

MATERIALS AND METHODS

Six CNVs were induced in the left eyes of 8-week-old male Brown Norway rats. Immediately after the induction of CNV, 4 μl of baicalin solution (0.1, 1 or 5 nmol) and 4 μl of a solution containing 100 μg of bevacizumab were slowly injected into the vitreous cavity under direct observation with an operating microscope. At 14 days after CNV induction, fluorescein angiography (FA) was performed, and choroidal flat mounts were produced for quantitative assessment of CNV. The levels of the anti-angiogenic proteins vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF) and matrix metalloproteinase-2 (MMP-2) were determined via Western blot analysis.

RESULTS

FA of bevacizumab- and baicalin-treated rats showed significantly reduced CNV and leakage from the CNV lesions compared to control rats at day 14. Choroidal flat mounts revealed that baicalin inhibited the growth of CNV lesions in a dose-dependent manner. Western blot analysis demonstrated that baicalin significantly attenuated the up-regulation of VEGF, PDGF and MMP-2.

CONCLUSION

Baicalin suppressed laser-induced CNV formation in rats. These results suggest that baicalin should be considered as a candidate drug for treating exudative age-related macular degeneration.

Recent advances in molecular and cell biology of testicular germ-cell tumors

Testicular germ-cell tumors (TGCTs) are the most frequent solid malignant tumors in men 20-40 years of age and the most frequent cause of death from solid tumors in this age group. TGCTs comprise two major histologic groups: seminomas and nonseminomas germ-cell tumors (NSGCTs). NSGCTs can be further divided into embryonal, carcinoma, Teratoma, yolk sac tumor, and choriocarcinoma. Seminomas and NSGCTs present significant differences in clinical features, therapy, and prognosis, and both show characteristics of the primordial germ cells. Many discovered biomarkers including OCT3/4, SOX2, SOX17, HMGA1, Nek2, GPR30, Aurora-B, estrogen receptor β, and others have given further advantages to discriminate between histological subgroups and could represent useful novel molecular targets for antineoplastic strategies. More insight into the pathogenesis of TGCTs is likely to improve disease management not only to better treatment of these tumors but also to a better understanding of stem cells and oncogenesis.

Exploiting nanotechnology to overcome tumor drug resistance: Challenges and opportunities

Tumor cells develop resistance to chemotherapeutic drugs through multiple mechanisms. Overexpression of efflux transporters is an important source of drug resistance. Efflux transporters such as P-glycoprotein reduce intracellular drug accumulation and compromise drug efficacy. Various nanoparticle-based approaches have been investigated to overcome efflux-mediated resistance. These include the use of formulation excipients that inhibit transporter activity and co-delivery of the anticancer drug with a specific inhibitor of transporter function or expression. However, the effectiveness of nanoparticles can be diminished by poor transport in the tumor tissue. Hence, adjunct therapies that improve the intratumoral distribution of nanoparticles may be vital to the successful application of nanotechnology to overcome tumor drug resistance. This review discusses the mechanisms of tumor drug resistance and highlights the opportunities and challenges in the use of nanoparticles to improve the efficacy of anticancer drugs against resistant tumors.

Exploring the role of mitochondrial UQCRB in angiogenesis using small molecules

Bioactive small molecules are powerful tools used to evaluate protein function under physiological and pathological conditions. Over recent decades, utilization of a variety of biologically active small molecules in basic research and clinical applications has provided tremendous benefits in understanding the molecular mechanisms of biology and accelerating drug development. This review focuses on recent advances in the identification of new small molecules and their target proteins for exploring angiogenesis at the molecular level. In particular, we focus on the oxygen-sensing role of ubiquinol-cytochrome c reductase binding protein (UQCRB) of mitochondrial Complex III through identification of the protein target and the mode of action of a natural small molecule, terpestacin. The positive feedback approach of chemistry and biology provides a new way to explore functional roles of proteins and to translate this information into practical applications.

Molecular biomarkers as potential targets for therapeutic strategies in human testicular germ cell tumors: an overview

Testicular germ cell tumors (TGCTs), the most common malignancy in males between 15 and 34 years of age and the most frequent cause of death from solid tumors in this age group. TGCTs can be subdivided into seminoma and non-seminoma germ cell tumors (NSGCTs), including embryonal cell carcinoma, choriocarcinoma, yolk sac tumor, and teratoma. Seminomas and NSGCTs do not only present distinctive clinical features, but they also show significant differences as far as therapy and prognosis are concerned. Seminomas are highly sensitive to both radiation and chemotherapy, with a good prognosis, non-seminomas are sensitive to platinum-based combination chemotherapy and are less susceptible to radiation, with the exception of teratomas. The different therapeutic outcome might be explained by inherent properties of the cells from which testicular neoplasia originate. The unique treatment sensitivity of TGCTs is unexplained so far, but it is likely to be related to intrinsic molecular characteristics of the PGCs/gonocytes, from which these tumors originate. Many discovered bio-markers including OCT3/4, SOX2, SOX17, HMGA1, HMGA2, PATZ1, GPR30, Aurora B, estrogen receptor β, and others have given further advantages to discriminate between histological subgroups. In addition, therapeutic approaches for the treatment of TGCTs have been proposed: humanized antibodies against receptors/surface molecules on cancer cells, inhibitors of serine-threonine, and tyrosine kinases, and others. The mini-review will be an overview on the molecular alterations identified in TGCTs and on novel targeted antineoplastic strategies that might help to treat chemotherapy resistant TGCTs.

Recent advances in the biology of germ cell tumors: implications for the diagnosis and treatment

Testicular germ cell tumors (TGCT), are the most frequent solid malignant tumors in men 20-40 yr of age, and the most frequent cause of death from solid tumors in this age group. TGCT can be subdivided into seminoma and nonseminoma germ cell tumors (NSGCT), including embryonal cell carcinoma, choriocarcinoma, yolk sac tumor, and teratoma. Seminomas and NSGCT do not only present distinctive clinical features, but they also show significant differences as far as therapy and prognosis are concerned. Many novel markers have given further advantages to discriminate between histological subgroups. In addition, therapeutic approaches for the treatment of TGCT have been proposed: humanized antibodies against receptors/surface molecules on cancer cells, inhibitors of serine-threonine, and tyrosine kinases, and others. The review will focus on the recent advances in the research of molecular alterations identified in TGCT and on novel targeted anti-neoplastic strategies that might help to treat chemotherapy-resistant TGCT.

Tumor-Endothelial Cell Three-dimensional Spheroids: New Aspects to Enhance Radiation and Drug Therapeutics

Classic cancer research for several decades has focused on understanding the biology of tumor cells in vitro. However, extending these findings to in vivo settings has been impeded owing to limited insights on the impact of microenvironment on tumor cells. We hypothesized that tumor cell biology and treatment response would be more informative when done in the presence of stromal components, like endothelial cells, which exist in the tumor microenvironment. To that end, we have developed a system to grow three-dimensional cultures of GFP-4T1 mouse mammary tumor and 2H11 murine endothelial cells in hanging drops of medium in vitro. The presence of 2H11 endothelial cells in these three-dimensional cocultures was found to sensitize 4T1-GFP tumor cells to chemotherapy (Taxol) and, at the same time, protect cells from ionizing radiation. These spheroidal cultures can also be implanted into the dorsal skinfold window chamber of mice for fluorescence imaging of vascularization and disease progression/treatment response. We observed rapid neovascularization of the tumor-endothelial spheroids in comparison to tumor spheroids grown in nude mice. Molecular analysis revealed pronounced up-regulation of several proangiogenic factors in the tumor tissue derived from the tumor-endothelial spheroids compared with tumor-only spheroids. Furthermore, the rate of tumor growth from tumor-endothelial spheroids in mice was faster than the tumor cell-only spheroids, resulting in greater metastasis to the lung. This three-dimensional coculture model presents an improved way to investigate more pertinent aspects of the therapeutic potential for radiation and/or chemotherapy alone and in combination with antiangiogenic agents.

The sphingosine-1-phosphate derivative NHOBTD inhibits angiogenesis both in vitro and in vivo

Sphingosine-1-phosphate (S1P) plays an important role in angiogenesis by stimulating DNA synthesis, chemotactic motility, and early blood vessel formation. Accordingly, the S1P signaling pathway is an attractive target for novel anti-angiogenic therapeutics. Here, we describe a small synthetic derivative of S1P that acts as an anti-angiogenic agent. We found that the S1P derivative NHOBTD [N-((2S,3R)-3-hydroxy-1-morpholino-4-(3-octylphenyl)butan-2-yl)tetradecanamide] suppressed S1P-induced invasion and tube formation by human umbilical vein endothelial cells. NHOBTD also suppressed S1P signaling, as seen by destabilization of hypoxia inducible factor-1 alpha (HIF-1α) and secretion of VEGF, a transcriptional target of HIF-1α. Moreover, NHOBTD profoundly blocked endogenous neovascularization of the chick embryo chorioallantoic membrane, without rupturing any existing vessels. Together, these results demonstrate that NHOBTD is a new anti-angiogenic molecule that is capable of perturbing S1P signaling, and provides the basis for developing new anti-angiogenic drugs.

Concomitant vascular GRP-receptor and VEGF-receptor expression in human tumors: molecular basis for dual targeting of tumoral vasculature

Gastrin-releasing peptide (GRP) and GRP receptors (GRPR) play a role in tumor angiogenesis. Recently, GRPR were found to be frequently expressed in the vasculature of a large variety of human cancers. Here, we characterize these GRPR by comparing the vascular GRPR expression and localization in a selection of human cancers with that of an established biological marker of neoangiogenesis, the vascular endothelial growth factor (VEGF) receptor. In vitro quantitative receptor autoradiography was performed in parallel for GRPR and VEGF receptors (VEGFR) in 32 human tumors of various origins, using ¹²⁵I-Tyr-bombesin and ¹²⁵I-VEGF₁₆₅ as radioligands, respectively. Moreover, VEGFR-2 was evaluated immunohistochemically. All tumors expressed GRPR and VEGFR in their vascular system. VEGFR were expressed in the endothelium in the majority of the vessels. GRPR were expressed in a subpopulation of vessels, preferably in their muscular coat. The vessels expressing GRPR were all VEGFR-positive whereas the VEGFR-expressing vessels were not all GRPR-positive. GRPR expressing vessels were found immunohistochemically to co-express VEGFR-2. Remarkably, the density of vascular GRPR was much higher than that of VEGFR. The concomitant expression of GRPR with VEGFR appears to be a frequent phenomenon in many human cancers. The GRPR, localized and expressed in extremely high density in a subgroup of vessels, may function as target for antiangiogenic tumor therapy or angiodestructive targeted radiotherapy with radiolabeled bombesin analogs alone, or preferably together with VEGFR targeted therapy.

Bevacizumab and ocular wound healing after primary pterygium excision

PURPOSE

The aim of this study was to evaluate the effect of subconjunctival bevacizumab on early postoperative wound healing in patients with primary pterygium excision.

METHODS

In this randomized, double-blind, placebo-controlled study, the patients were randomized into 2 groups. Group 1 (G1) received a total of 7.5  mg bevacizumab (5  mg/0.2  mL on the day of surgery and 2.5  mg on the fourth day after surgery). Group 2 received 0.2  mL balanced salt solution at the end of surgery. Postoperatively, patients were examined at 1 day, 1 week, and 1 month. The following parameters were evaluated: horizontal length of the corneal epithelial defect (in millimeters), conjunctival erythema, conjunctival flap edema, subconjunctival hemorrhage, lacrimation, and photophobia. Any complications of conjunctival flaps such as retraction and melting or wound infection were recorded.

RESULTS

There were no statistically significant differences for age, sex, operated eye, and horizontal size of pterygium among 44 eyes of 44 patients, 22 in each group. No patient had conjunctival flap melting or retraction, keratitis, or nonhealing corneal epithelial defect. No statistically significant differences were observed between the groups for the evaluated measures except for conjunctival erythema at the first postoperative day (P = 0.005), which was more common in G1. Although the horizontal length of corneal epithelial defect in G1 was twice that of group 2 on the seventh postoperative day (average 0.09 vs. 0.04  mm, range 0-1 vs. 0-0.3  mm), the difference was not statistically significant (P = 0.45).

CONCLUSION

No adverse effect on early postoperative wound healing of excised primary pterygium was observed in patients who received subconjunctival bevacizumab.

Effect of intracameral bevacizumab injection on corneal endothelial cells: an in vivo evaluation

BACKGROUND

We studied the effect of an intracameral bevacizumab injection on the corneal endothelium and iris neovessels (INV).

METHODS

Ten eyes were studied in 10 patients with an average age of 52.1 +/- 13.17 years. Patients underwent intracameral bevacizumab injections at a concentration of 1.25 mg/0.05 mL. Intraocular pressure, best-corrected visual acuity, gonioscopy, neovascular membrane extent, anterior segment photography, iris fluorescein angiography, pachymetry, and specular microscopy were recorded preoperatively and postoperatively.

RESULTS

The minimum follow-up period was 4 months. INVs started to regress within the first 2 days after the injection and regressed completely by the end of the fourth week. Reduction in INV leakage started 1 week after injection, and resolved in 8 eyes (80%) by the end of the fourth week. Intraocular pressure dropped significantly from 17.8 +/- 4.8 mmHg to 16.6 +/- 2.8 mmHg over 4 weeks. The mean endothelial cell loss was 3.95% +/- 6.78%.

CONCLUSIONS

An intracameral bevacizumab injection proved to be safe for corneal endothelial cells.

Epidermal growth factor receptor inhibition modulates the microenvironment by vascular normalization to improve chemotherapy and radiotherapy efficacy

Background

Epidermal growth factor receptor (EGFR) inhibitors have shown only modest clinical activity when used as single agents to treat cancers. They decrease tumor cell expression of hypoxia-inducible factor 1-α (HIF-1α) and vascular endothelial growth factor (VEGF). Hypothesizing that this might normalize tumor vasculature, we examined the effects of the EGFR inhibitor erlotinib on tumor vascular function, tumor microenvironment (TME) and chemotherapy and radiotherapy sensitivity.

Methodology/Principal Findings

Erlotinib treatment of human tumor cells in vitro and mice bearing xenografts in vivo led to decreased HIF-1α and VEGF expression. Treatment altered xenograft vessel morphology assessed by confocal microscopy (following tomato lectin injection) and decreased vessel permeability (measured by Evan's blue extravasation), suggesting vascular normalization. Erlotinib increased tumor blood flow measured by Power Doppler ultrasound and decreased hypoxia measured by EF5 immunohistochemistry and tumor O₂ saturation measured by optical spectroscopy. Predicting that these changes would improve drug delivery and increase response to chemotherapy and radiation, we performed tumor regrowth studies in nude mice with xenografts treated with erlotinib and either radiotherapy or the chemotherapeutic agent cisplatin. Erlotinib therapy followed by cisplatin led to synergistic inhibition of tumor growth compared with either treatment by itself (p<0.001). Treatment with erlotinib before cisplatin led to greater tumor growth inhibition than did treatment with cisplatin before erlotinib (p = 0.006). Erlotinib followed by radiation inhibited tumor regrowth to a greater degree than did radiation alone, although the interaction between erlotinib and radiation was not synergistic.

Conclusions/Significance

EGFR inhibitors have shown clinical benefit when used in combination with conventional cytotoxic therapy. Our studies show that targeting tumor cells with EGFR inhibitors may modulate the TME via vascular normalization to increase response to chemotherapy and radiotherapy. These studies suggest ways to assess the response of tumors to EGFR inhibition using non-invasive imaging of the TME.

A review on bevacizumab and surgical wound healing: an important warning to all surgeons

Bevacizumab (Avastin, Genentech, Inc, San Francisco, CA), a humanized monoclonal antibody against vascular endothelial growth factor, was recently approved for the treatment of metastatic breast cancer.A PubMed and OVID search was performed using keywords: bevacizumab, Avastin, wound healing, VEGF, angiogenesis, and colorectal cancer. Our objective was to review the current literature in regard to bevacizumab and its adverse effects on surgical wound healing.Bevacizumab has been associated with multiple complications in regard to wound healing, such as dehiscence, ecchymosis, surgical site bleeding, and wound infection. Current literature suggests patients should wait at least 6 to 8 weeks (>40 days) after cessation to have surgery (half-life = 20 days). In addition, postoperative reinitiation of bevacizumab must wait > or =28 days to prevent an increased risk of wound healing complications, and the surgical incision should be fully healed.The adverse effects of bevacizumab in regard to wound healing must be considered in all surgical patients.

Launching a novel preclinical infrastructure: comparative oncology trials consortium directed therapeutic targeting of TNFalpha to cancer vasculature

Background

Under the direction and sponsorship of the National Cancer Institute, we report on the first pre-clinical trial of the Comparative Oncology Trials Consortium (COTC). The COTC is a novel infrastructure to integrate cancers that naturally develop in pet dogs into the development path of new human drugs. Trials are designed to address questions challenging in conventional preclinical models and early phase human trials. Large animal spontaneous cancer models can be a valuable addition to successful studies of cancer biology and novel therapeutic drug, imaging and device development.

Methodology/Principal Findings

Through this established infrastructure, the first trial of the COTC (COTC001) evaluated a targeted AAV-phage vector delivering tumor necrosis factor (RGD-A-TNF) to αV integrins on tumor endothelium. Trial progress and data was reviewed contemporaneously using a web-enabled electronic reporting system developed for the consortium. Dose-escalation in cohorts of 3 dogs (n = 24) determined an optimal safe dose (5×10¹² transducing units intravenous) of RGD-A-TNF. This demonstrated selective targeting of tumor-associated vasculature and sparing of normal tissues assessed via serial biopsy of both tumor and normal tissue. Repetitive dosing in a cohort of 14 dogs, at the defined optimal dose, was well tolerated and led to objective tumor regression in two dogs (14%), stable disease in six (43%), and disease progression in six (43%) via Response Evaluation Criteria in Solid Tumors (RECIST).

Conclusions/Significance

The first study of the COTC has demonstrated the utility and efficiency of the established infrastructure to inform the development of new cancer drugs within large animal naturally occurring cancer models. The preclinical evaluation of RGD-A-TNF within this network provided valuable and necessary data to complete the design of first-in-man studies.

High sensitivity: high-resolution SPECT-CT/MR molecular imaging of angiogenesis in the Vx2 model

OBJECTIVES

The use of antiangiogenic therapy in conjunction with traditional chemotherapy is becoming increasingly in cancer management, but the optimal benefit of these targeted pharmaceuticals has been limited to a subset of the population treated. Improved imaging probes that permit sensitive detection and high-resolution characterization of tumor angiogenesis could improve patient risk-benefit stratification. The overarching objective of these experiments was to develop a dual modality alpha(nu)beta3-targeted nanoparticle molecular imaging agent that affords sensitive nuclear detection in conjunction with high-resolution MR characterization of tumor angiogenesis.

MATERIALS AND METHODS

In part 1, New Zealand white rabbits (n = 21) bearing 14d Vx2 tumor received either alpha(nu)beta3-targeted 99mTc nanoparticles at doses of 11, 22, or 44 MBq/kg, nontargeted 99mTc nanoparticles at 22 MBq/kg, or alpha(nu)beta3-targeted 99mTc nanoparticles (22 MBq/kg) competitively inhibited with unlabeled alpha(nu)beta3-nanoparticles. All animals were imaged dynamically over 2 hours with a planar camera using a pinhole collimator. In part 2, the effectiveness of alpha(nu)beta3-targeted 99mTc nanoparticles in the Vx2 rabbit model was demonstrated using clinical SPECT-CT imaging techniques. Next, MR functionality was incorporated into alpha(nu)beta3-targeted 99mTc nanoparticles by inclusion of lipophilic gadolinium chelates into the outer phospholipid layer, and the concept of high sensitivity - high-resolution detection and characterization of tumor angiogenesis was shown using sequential SPECT-CT and MR molecular imaging with 3D neovascular mapping.

RESULTS

alpha(nu)beta3-Targeted 99mTc nanoparticles at 22 MBq/kg produced the highest tumor-to-muscle contrast ratio (8.56 +/- 0.13, TMR) versus the 11 MBq/kg (7.32 +/- 0.12) and 44 MBq/kg (6.55 +/- 0.07) doses, (P < 0.05). TMR of nontargeted particles at 22.2 MBq/kg (5.48 +/- 0.09) was less (P < 0.05) than the equivalent dosage of alpha(nu)beta3-targeted 99mTc nanoparticles. Competitively inhibition of 99mTc alpha(nu)beta3-integrin-targeted nanoparticles at 22.2 MBq/kg reduced (P < 0.05) TMR (5.31 +/- 0.06) to the nontargeted control contrast level. Multislice CT imaging could not distinguish the presence of Vx2 tumor implanted in the popliteal fossa from lymph nodes in the same fossa or in the contralateral leg. However, the use of 99mTc alpha(nu)beta3-nanoparticles with SPECT-CT produced a clear neovasculature signal from the tumor that was absent in the nonimplanted hind leg. Using alpha(nu)beta3-targeted 99mTc-gadolinium nanoparticles, the sensitive detection of the Vx2 tumor was extended to allow MR molecular imaging and 3D mapping of angiogenesis in the small tumor, revealing an asymmetrically distributed, patchy neovasculature along the periphery of the cancer.

CONCLUSION

Dual modality molecular imaging with alpha(nu)beta3-targeted 99mTc-gadolinium nanoparticles can afford highly sensitive and specific localization of tumor angiogenesis, which can be further characterized with high-resolution MR neovascular mapping, which may predict responsiveness to antiangiogenic therapy.

Molecular and cell biology of testicular germ cell tumors

Although testicular germ cell tumors (TGCTs) are relatively uncommon, they are particularly important as they tend to affect children and young men, representing the most common tumor in male aged from 20 to 40years. TGCTs are a heterogeneous group of tumors, with specific peculiarities reflecting on epidemiologic distribution and clinic-pathological features. TGCTs show a high-cure rates in both seminomas and nonseminomas and represent the model of a curable neoplasia: sensitive serum tumor markers, accurate prognostic classification, contribute to a high effectiveness of cancer therapy. However, up to 30% of patients diagnosed with metastatic nonseminomas do not achieve a durable remission, and in metastatic teratomas cisplatin-based treatment resistance has been observed. These different prognostic and therapeutic features of TGCTs highlight the need for a better understanding of the molecular biology of TGCT, that could help to improve disease management and to tailor aggressiveness of treatment to the severity of the prognosis.

Metabolism of 5-isopropyl-6-(5-methyl-1,3,4-oxadiazol-2-yl)-N-(2-methyl-1H-pyrrolo[2,3-b]pyridin-5-yl)pyrrolo[2,1-f][1,2,4]triazin-4-amine (BMS-645737): identification of an unusual N-acetylglucosamine conjugate in the cynomolgus monkey

5-Isopropyl-6-(5-methyl-1,3,4-oxadiazol-2-yl)-N-(2-methyl-1H-pyrrolo[2,3-b]pyridin-5-yl)pyrrolo[2,1-f][1,2,4]triazin-4-amine (BMS-645737) is a potent and selective vascular endothelial growth factor receptor-2 antagonist. In this study, liquid chromatography/tandem mass spectrometry and NMR were used to investigate the biotransformation of BMS-645737 in vitro and in the cynomolgus monkey, dog, mouse, and rat. Metabolic pathways for BMS-645737 included multistep processes involving both oxidation and conjugation reactions. For example, the 2-methyl-1H-pyrrolo moiety underwent cytochrome P450-catalyzed hydroxylation followed by oxidation to a carboxylic acid and then conjugation with taurine. Alternatively, the 5-methyl-1,3,4-oxadiazol-2-yl moiety was metabolized by hydroxylation and then conjugation with sulfate. The pyridin-5-yl group underwent direct glucuronidation in hepatocytes (dog, monkey, human) and conjugation with N-acetylglucosamine in the monkey. Conjugation with glutathione and processing along the mercapturic acid pathway was a minor metabolic pathway in vivo, although BMS-645737 did not form conjugates in the presence of glutathione-supplemented liver microsomes. Other minor biotransformation pathways included oxidative dehydrogenation, dihydroxylation, and hydrolytic opening of the oxadiazole ring followed by either deacetylation or hydrolysis of the resulting diacyl hydrazide. Whereas previous studies have shown the formation of N-acetylglucosamine conjugates of alcohols, arylamines, and other small molecules, this report describes the biotransformation of a heterocyclic aromatic amine via direct conjugation with N-acetylglucosamine.

Reversible skeletal changes after treatment with bevacizumab in a child with cutaneovisceral angiomatosis with thrombocytopenia syndrome

Cutaneovisceral angiomatosis with thrombocytopenia (CAT) syndrome is a rare vascular disorder of the skin and gastrointestinal tract for which there is no standard treatment. We present a case in which a child with CAT syndrome was treated with bevacizumab, a vascular endothelial growth factor inhibitor, and subsequently developed asymptomatic metaphyseal bone lesions. Though not previously described as a side effect, we hypothesize that the use of bevacizumab in a child with active epiphyseal growth plates caused these radiographic lesions. Because of the potential for altered bone growth and metabolism, children receiving VEGF inhibitors should be monitored closely for bony toxicity.

Three-dimensional MR mapping of angiogenesis with alpha5beta1(alpha nu beta3)-targeted theranostic nanoparticles in the MDA-MB-435 xenograft mouse model

Our objectives were 1) to characterize angiogenesis in the MDA-MB-435 xenograft mouse model with three-dimensional (3D) MR molecular imaging using alpha(5)beta(1)(RGD)- or irrelevant RGS-targeted paramagnetic nanoparticles and 2) to use MR molecular imaging to assess the antiangiogenic effectiveness of alpha(5)beta(1)(alpha(nu)beta(3))- vs. alpha(nu)beta(3)-targeted fumagillin (50 mug/kg) nanoparticles. Tumor-bearing mice were imaged with MR before and after administration of either alpha(5)beta(1)(RGD) or irrelevant RGS-paramagnetic nanoparticles. In experiment 2, mice received saline or alpha(5)beta(1)(alpha(nu)beta(3))- or alpha(nu)beta(3)-targeted fumagillin nanoparticles on days 7, 11, 15, and 19 posttumor implant. On day 22, MRI was performed using alpha(5)beta(1)(alpha(nu)beta(3))-targeted paramagnetic nanoparticles to monitor the antiangiogenic response. 3D reconstructions of alpha(5)beta(1)(RGD)-signal enhancement revealed a sparse, asymmetrical pattern of angiogenesis along the tumor periphery, which occupied <2.0% tumor surface area. alpha(5)beta(1)-targeted rhodamine nanoparticles colocalized with FITC-lectin corroborated the peripheral neovascular signal. alpha(5)beta(1)(alpha(nu)beta(3))-fumagillin nanoparticles decreased neovasculature to negligible levels relative to control; alpha(nu)beta(3)-targeted fumagillin nanoparticles were less effective (P>0.05). Reduction of angiogenesis in MDA-MB-435 tumors from low to negligible levels did not decrease tumor volume. MR molecular imaging may be useful for characterizing tumors with sparse neovasculature that are unlikely to have a reduced growth response to targeted antiangiogenic therapy.

[Value of targeted treatment for testicular cancer: from molecular approaches to clinical possibilities]

Due to the introduction of tyrosine kinase-inhibitors in the treatment of metastatic renal cell cancer, targeted therapy raises hopes for other urological tumors as well. Even if excellent cure rates, achieved by standardization of diagnosis und therapy, have made testicular cancer a curable disease, up to 6% of young patients still die from tumors refractory to therapy. The quality of life of patients in advanced stages needing aggressive treatment should be improved by new therapies with reduced side effects. The role of tyrosine kinase inhibitors and angiogenesis inhibitors as well as intervention in the cell cycle and induction of apoptosis are discussed.

Developing and applying a gene functional association network for anti-angiogenic kinase inhibitor activity assessment in an angiogenesis co-culture model

Background

Tumor angiogenesis is a highly regulated process involving intercellular communication as well as the interactions of multiple downstream signal transduction pathways. Disrupting one or even a few angiogenesis pathways is often insufficient to achieve sustained therapeutic benefits due to the complexity of angiogenesis. Targeting multiple angiogenic pathways has been increasingly recognized as a viable strategy. However, translation of the polypharmacology of a given compound to its antiangiogenic efficacy remains a major technical challenge. Developing a global functional association network among angiogenesis-related genes is much needed to facilitate holistic understanding of angiogenesis and to aid the development of more effective anti-angiogenesis therapeutics.

Results

We constructed a comprehensive gene functional association network or interactome by transcript profiling an in vitro angiogenesis model, in which human umbilical vein endothelial cells (HUVECs) formed capillary structures when co-cultured with normal human dermal fibroblasts (NHDFs). HUVEC competence and NHDF supportiveness of cord formation were found to be highly cell-passage dependent. An enrichment test of Biological Processes (BP) of differentially expressed genes (DEG) revealed that angiogenesis related BP categories significantly changed with cell passages. Built upon 2012 DEGs identified from two microarray studies, the resulting interactome captured 17226 functional gene associations and displayed characteristics of a scale-free network. The interactome includes the involvement of oncogenes and tumor suppressor genes in angiogenesis. We developed a network walking algorithm to extract connectivity information from the interactome and applied it to simulate the level of network perturbation by three multi-targeted anti-angiogenic kinase inhibitors. Simulated network perturbation correlated with observed anti-angiogenesis activity in a cord formation bioassay.

Conclusion

We established a comprehensive gene functional association network to model in vitro angiogenesis regulation. The present study provided a proof-of-concept pilot of applying network perturbation analysis to drug phenotypic activity assessment.

Discovery and preclinical studies of 5-isopropyl-6-(5-methyl-1,3,4-oxadiazol-2-yl)-N-(2-methyl-1H-pyrrolo[2,3-b]pyridin-5-yl)pyrrolo[2,1-f][1,2,4]triazin-4-amine (BMS-645737), an in vivo active potent VEGFR-2 inhibitor

We report herein a series of substituted N-(1H-pyrrolo[2,3-b]pyridin-5-yl)pyrrolo[2,1-f][1,2,4]triazin-4-amines as inhibitors of vascular endothelial growth factor receptor-2 tyrosine kinase. Through structure-activity relationship studies, biochemical potency, pharmacokinetics, and kinase selectivity were optimized to afford BMS-645737 (13), a compound with good preclinical in vivo activity against human tumor xenograft models.

Alkylphospholipids inhibit capillary-like endothelial tube formation in vitro: antiangiogenic properties of a new class of antitumor agents

Synthetic alkylphospholipids (APLs), such as edelfosine, miltefosine and perifosine, constitute a new class of antineoplastic compounds with various clinical applications. Here we have evaluated the antiangiogenic properties of APLs. The sensitivity of three types of vascular endothelial cells (ECs) (bovine aortic ECs, human umbilical vein ECs and human microvascular ECs) to APL-induced apoptosis was dependent on the proliferative status of these cells and correlated with the cellular drug incorporation. Although confluent, nondividing ECs failed to undergo apoptosis, proliferating ECs showed a 3-4-fold higher uptake and significant levels of apoptosis after APL treatment. These findings raised the question of whether APLs interfere with new blood vessel formation. To test the antiangiogenic properties in vitro, we studied the effect of APLs using two different experimental models. The first one tested the ability of human microvascular ECs to invade a three-dimensional human fibrin matrix and form capillary-like tubular networks. In the second model, bovine aortic ECs were grown in a collagen gel sandwich to allow tube formation. We found that all three APLs interfered with endothelial tube formation in a dose-dependent manner, with a more than 50% reduction at 25 micromol/l. Interference with the angiogenic process represents a novel mode of action of APLs and might significantly contribute to the antitumor effect of these compounds.

Blood pressure rise following angiogenesis inhibition by bevacizumab. A crucial role for microcirculation

Arterial hypertension (HT) has been reported in all studies involving bevacizumab, an antiangiogenic agent designed to target vascular endothelial growth factor (VEGF). The mechanism underlying bevacizumab-related HT is not yet clearly understood. As far as endothelial dysfunction and microvascular rarefaction are hallmarks in all forms of HT, we tested the hypothesis that anti-VEGF therapy could alter the microcirculation in nontumor tissues and, thus, result in an increase in blood pressure (BP). We used intravital video microscopy to measure dermal capillary densities in the dorsum of the fingers. Microvascular endothelial function was assessed by laser Doppler flowmetry combined with iontophoresis of pilocarpine (acetylcholine analogue). All measurements were carried out in 18 patients before and after a 6-month treatment with bevacizumab (mean cumulative dose: 3.16 +/- 0.90 g). Mean BP was increased after 6 months of therapy compared with baseline, from 129 +/- 13/75 +/- 7 mmHg to 145 +/- 17/82 +/- 7 mmHg for systolic BP and diastolic BP, respectively (P < 0.0001). Compared with the baseline, mean dermal capillary density at 6 months was significantly lower (75 +/- 12 versus 83 +/- 13/mm(2); P < 0.0001), as well as pilocarpine-induced vasodilation (P < 0.05). Thus, bevacizumab treatment resulted in endothelial dysfunction and capillary rarefaction; both changes are closely associated and could be responsible for the rise in BP observed in most patients.

Angiogenesis as a therapeutic target in arthritis: learning the lessons of the colorectal cancer experience

The idea of a therapeutic modality aimed at 'starving' a tissue of blood vessels, and consequentially of oxygen and nutrients, was born from the concept that blood vessel formation (angiogenesis) is central to the progression and maintenance of diseases which involve tissue expansion/invasion. In the first instance, solid malignancies were the target for anti-angiogenic treatments, with colorectal cancer being the first disease for which an angiogenesis inhibitor--anti-vascular endothelial growth factor antibody bevacizumab--was approved in 2004. Our understanding of the pathogenesis of rheumatoid arthritis (RA) has lead to many parallels being drawn between this chronic inflammatory disease and solid tumours, in that both involve tissue expansion, invasion, expression of cytokines and growth factors and areas of hypoxia/hypoperfusion. As a result, angiogenesis blockade has been touted as a possible treatment for RA. The lessons learnt during the progression of eventually successful therapies such as bevacizumab should undoubtedly guide us in the future development of comparable treatments for RA.

Rapidly acting antitumoral antiangiogenic therapies

We deal with a biophysical description of antitumor antiangiogenic therapies. In particular, by means of some simple models, we study the possible effects of the delay between the drug consumption by endothelial cells and their death on the outcome of the therapy. We have found that this time lag implies an increase in the minimal dose guaranteeing tumor eradication and, if the delay is greater than a meaningful threshold, it may preclude the total regression. These results might be of interest in better understanding the causes underlying the contradictory literature on the clinical trials of antiangiogenic therapies.

SAR of a novel ‘Anthranilamide Like’ series of VEGFR-2, multi protein kinase inhibitors for the treatment of cancer

Novel anthranilamides were surprisingly found to exert additional activity on B-RAF. Corresponding thiophene, pyrazole, and thiazole core analogs were prepared as VEGFR-2 inhibitors with c-KIT, and B-RAF activity. Compounds in the phenyl, thiophene, and thiazole series are in vivo active.

Quantification of human angiogenesis in immunodeficient mice using a photon counting-based method

Testing new antiangiogenic drugs for cancer treatment requires the use of animal models, since stromal cells and extracellular matrices mediate signals to endothelial cells that cannot be fully reproduced in vitro. Most methods used for analysis of antiangiogenic drugs in vivo utilized histologic examination of tissue specimens, which often requires large sample sizes to obtain reliable quantitative data. Furthermore, these assays rely on the analysis of murine vasculature that may not be correlated with the responses of human endothelial cells. Here, we engineered human blood vessels in immunodeficient mice with human endothelial cells expressing luciferase, demonstrated that these cells line functional blood vessels, and quantified angiogenesis over time using a photon counting-based method. In a proof-of-principle experiment with PTK/ZK, a small molecule inhibitor of vascular endothelial growth factor (VEGF) tyrosine kinase receptors, a strong correlation was observed between the decrease in bioluminescence (9.12-fold) in treated mice and the actual decrease in microvessel density (9.16-fold) measured after retrieval of the scaffolds and immunohistochemical staining of endothelial cells. The method described here allows for quantitative and noninvasive investigation into the effects of anti-cancer drugs on human angiogenesis in a murine host.

Mutant V600E BRAF increases hypoxia inducible factor-1alpha expression in melanoma

Mutations in the BRAF serine/threonine kinase gene are frequently found in cutaneous melanomas. Activation of hypoxia inducible factor-1alpha (HIF-1alpha) in response to both hypoxic stress and oncogenic signals has important implications in cancer development and progression. Here, we report that mutant BRAF(V600E) increases HIF-1alpha expression in melanoma cells. Our microarray profiling data in 35 melanoma and melanocyte cell lines showed that HIF-1alpha gene expression was significantly increased in melanomas harboring BRAF(V600E) mutation. Stable suppression of mutant BRAF(V600E) or both wild-type and mutant BRAF(V600E) by RNA interference in melanoma cells resulted in significantly decreased HIF-1alpha expression. Knockdown of mutant BRAF(V600E) induced significant reduction of cell survival and proliferation under hypoxic conditions, whereas knockdown of both wild-type and mutant BRAF(V600E) resulted in further reduction. The effects of BRAF knockdown can be rescued by reintroducing BRAF(V600E) into tumor cells. Transfection of BRAF(V600E) into melanoma cells with wild-type BRAF induced significantly more hypoxic tolerance. Knockdown of HIF-1alpha in melanoma cells resulted in decreased cell survival under hypoxic conditions. Pharmacologic inhibition of BRAF by BAY 43-9006 also resulted in decreased HIF-1alpha expression. Although HIF-1alpha translational rate was not changed, the protein was less stable in BRAF knockdown cells. In additional, von Hippel-Lindau protein expression was significantly increased in BRAF knockdown cells. Our data show for the first time that BRAF(V600E) mutation increases HIF-1alpha expression and melanoma cell survival under hypoxic conditions and suggest that effects of the oncogenic V600E BRAF mutation may be partially mediated through the HIF-1alpha pathway.

KDR expression is associated with the stage and cigarette smoking of the patients with lung cancer

PURPOSE

Kinase insert domain-containing receptor (KDR) is one of the molecular targets used in cancer therapy. We studied the KDR expression characteristics and the relationship with the clinical parameters of the patients with lung cancer, to give the basic evidence and clue for tailoring therapy.

METHODS

Reverse transcriptase and real-time PCR were used to evaluate the KDR mRNA expression levels in 222 tissue samples (106 tumor tissues, 106 matched normal tissues obtained from the same patients with lung cancer, and 10 normal lung specimens from individuals without lung cancer). The KDR mRNA expression level and clinical parameters were analyzed by paired-sample t test, ANOVA and linear regression, respectively. The Kaplan-Meier method and the log-rank test were used for survival analysis. Expression of KDR protein was also examined immunohistochemically in 15 tumor samples and 15 matched normal lung specimens.

RESULTS

The KDR mRNA expression levels were significantly higher in normal tissues (mean 4.50 +/- 0.51) than that in the carcinoma tissues (mean 4.12 +/- 0.50, P < 0.0005). KDR expression in tumor tissues is associated with the histological status, tumor stage, cigarette smoking, and N stage of the patients with lung cancer (P < 0.05) analyzed by using ANOVA methods. Multivariate analysis showed that tumor stages and cigarette smoking status were the two most important independent predictors for the KDR expression levels in tumor tissues (R = 0.415, R (2) = 0.172, F = 10.694, P < 0.0005). Tumors with KDR mRNA expression levels above the mean had a shorter survival (466 +/- 313 days) than did patients with KDR expression levels below the mean (671 +/- 264 days), whereas Kaplan-Meier analysis and log-rank test showed no significant difference in the overall survival between the patients (P = 0.2055). All the 15 normal lung tissues detected showed scale 2 KDR immunostaining. The intensity of immunostaining for KDR in tumor specimens varied from negative (scale 0) to strongest (scale 3) staining.

CONCLUSIONS

Locally advanced and non-cigarette smoking patients with lung cancer may be the two valuable surrogate markers for KDR mRNA higher levels. Non-squamous lung cancer, N 2 stage may be the secondary markers for that. The KDR expression level in normal lung tissue is stable, but varied in tumor tissues. Targeting KDR therapy in lung cancer might considerate these clinical and KDR expression information. Further confirmation study must be needed.

Viral serpin, Serp-1, inhibits endogenous angiogenesis in the chicken chorioallantoic membrane model

BACKGROUND

Angiogenesis is a critical factor in the development of malignant tumors, in arthritic joints, and in cardiovascular disease. In cardiovascular disease, angiogenesis is recognised both as a potential therapy and as a complicating factor in atherosclerotic plaque rupture and thrombotic obstruction. Serine proteases regulate thrombosis, inflammation, and cell invasion, events that trigger various stages of angiogenesis and are in turn regulated by inhibitors, termed serpins. Serp-1 is a secreted anti-inflammatory viral serpin that profoundly inhibits early mononuclear cell invasion, and the development of atherosclerosis, transplant vasculopathy, and arthritis in a range of animal models.

METHODS

The capacity of Serp-1 to alter angiogenesis was evaluated in the chicken chorioallantoic membrane (CAM) model using morphometric analysis of vascular changes and RT-PCR to explore alterations in gene expression.

RESULTS

Serp-1 inhibited endogenous angiogenesis in a dose-dependent manner, with associated altered expression of laminin and vascular endothelial growth factor (VEGF). Serp-1 was ineffective in CAMs no longer in the rapid growth phase. Similar inhibition of angiogenesis was detected after inhibition of VEGF, but not after treatment with the inactivated reactive center loop mutant of Serp-1.

CONCLUSIONS

The angiogenic process can be controlled using Serp-1, an anti-inflammatory agent that is effective at low concentrations with rapid reversibility, targets endothelial cells, and reduces the availability of VEGF. These properties may be especially important in cardiovascular disease, reducing plaque destabilization. It is likely that the anti-angiogenic activity of Serp-1 contributes to the observed anti-inflammatory and anti-atherogenic actions with potential importance in this therapeutic setting.

Nitric Oxide and Its Gatekeeper Thrombospondin-1 in Tumor Angiogenesis: Fig. 1

Nitric oxide (NO) plays a central role in angiogenesis as a mediator of signaling by vascular endothelial growth factor and other angiogenic factors. Low concentrations of NO produced in response to angiogenic factors stimulate angiogenesis, whereas higher concentrations typical of inflammatory responses inhibit angiogenesis. The proangiogenic activity of NO is mediated by activation of soluble guanylyl cyclase, leading to cyclic guanosine 3',5'-monophosphate accumulation and activation of its target kinases and ion channels. The four angiogenesis inhibitors currently approved for clinical use target components of the signaling cascade upstream of NO. New research has identified components downstream of NO as the primary target of the endogenous angiogenesis inhibitor thrombospondin-1 and has shown that circulating levels of thrombospondin-1 are sufficient to limit angiogenic responses by antagonizing NO signaling. This provides new insights into the significance of the widespread loss of thrombospondin-1 expression during malignant progression. Although clinical trials suggest that blocking NO signaling can inhibit tumor angiogenesis, this approach also inactivates inhibitory signaling from thrombospondin-1. We discuss the implications of the balance between these pathways for applying thrombospondin-1 mimetics and redox modifiers as cancer therapeutics.