Functional genomics of endothelial cells treated with anti-angiogenic or angiopreventive drugs

Angiogenesis is a highly regulated physiological process that has been studied in considerable detail given its importance in several chronic pathologies. Many endogenous factors and hormones intervene in the regulation of angiogensis and classical as well as targeted drugs have been developed for its control. Angiogenesis inhibition has come off the bench and entered into clinical application for cancer therapy, particularly for metastatic disease. While the clinical benefit is currently in terms of months, preclinical data suggest that novel drugs and drug combinations could lead to substantial improvement. The many targets of endogenous angiogenesis inhibitors reflect the complexity of the process; in contrast, current clinical therapies mainly target the vascular endothelial growth factor system. Cancer chemopreventive compounds can retard tumor insurgence and delay or prevent metastasis and many of these molecules hinder angiogenesis, a mechanism that we termed angioprevention. Angiopreventive drugs appear to prevalently act through the inhibition of the pro-inflammatory and anti-apoptotic player NFkappaB, thus contrasting inflammation dependent angiogenesis. Relatively little is known concerning the effects of these angiogenesis inhibitors on gene expression of endothelial cells, the main target of many of these molecules. Here we provide an exhaustive list of anti-angiogenic molecules, and summarize their effects, where known, on the transcriptome and functional genomics of endothelial cells. The regulation of specific genes can be crucial to preventive or therapeutic intervention. Further, novel targets might help to circumvent resistance to anti-angiogenic therapy. The studies we review are relevant not only to cancer but also to other chronic degenerative diseases involving endothelial cells, such as cardiovascular disorders, diabetes, rheumatoid arthritis and retinopaties, as well as vessel aging.

Cardiotoxicity of anticancer drugs: the need for cardio-oncology and cardio-oncological prevention

Due to the aging of the populations of developed countries and a common occurrence of risk factors, it is increasingly probable that a patient may have both cancer and cardiovascular disease. In addition, cytotoxic agents and targeted therapies used to treat cancer, including classic chemotherapeutic agents, monoclonal antibodies that target tyrosine kinase receptors, small molecule tyrosine kinase inhibitors, and even antiangiogenic drugs and chemoprevention agents such as cyclooxygenase-2 inhibitors, all affect the cardiovascular system. One of the reasons is that many agents reach targets in the microenvironment and do not affect only the tumor. Combination therapy often amplifies cardiotoxicity, and radiotherapy can also cause heart problems, particularly when combined with chemotherapy. In the past, cardiotoxic risk was less evident, but it is increasingly an issue, particularly with combination therapy and adjuvant therapy. Today's oncologists must be fully aware of cardiovascular risks to avoid or prevent adverse cardiovascular effects, and cardiologists must now be ready to assist oncologists by performing evaluations relevant to the choice of therapy. There is a need for cooperation between these two areas and for the development of a novel discipline, which could be termed cardio-oncology or onco-cardiology. Here, we summarize the potential cardiovascular toxicities for a range of cancer chemotherapeutic and chemopreventive agents and emphasize the importance of evaluating cardiovascular risk when patients enter into trials and the need to develop guidelines that include collateral effects on the cardiovascular system. We also discuss mechanistic pathways and describe several potential protective agents that could be administered to patients with occult or overt risk for cardiovascular complications.

Identification, isolation and expansion of myoendothelial cells involved in leech muscle regeneration

Adult skeletal muscle in vertebrates contains myoendothelial cells that express both myogenic and endothelial markers, and which are able to differentiate into myogenic cells to contribute to muscle regeneration. In spite of intensive research efforts, numerous questions remain regarding the role of cytokine signalling on myoendothelial cell differentiation and muscle regeneration. Here we used Hirudo medicinalis (Annelid, leech) as an emerging new model to study myoendothelial cells and muscle regeneration. Although the leech has relative anatomical simplicity, it shows a striking similarity with vertebrate responses and is a reliable model for studying a variety of basic events, such as tissue repair. Double immunohistochemical analysis were used to characterize myoendothelial cells in leeches and, by injecting in vivo the matrigel biopolymer supplemented with the cytokine Vascular Endothelial Growth Factor (VEGF), we were able to isolate this specific cell population expressing myogenic and endothelial markers. We then evaluated the effect of VEGF on these cells in vitro. Our data indicate that, similar to that proposed for vertebrates, myoendothelial cells of the leech directly participate in myogenesis both in vivo and in vitro, and that VEGF secretion is involved in the recruitment and expansion of these muscle progenitor cells.

Metabolic regulation and redox activity as mechanisms for angioprevention by dietary phytochemicals

The existence of active principles in numerous foods and beverages has been recognized by traditional medicines worldwide after centuries of empirical trial. Epidemiological studies support the concepts linking diet to survival, particularly in the incidence rates of specific cancers. Molecular studies have provided evidence that a wide range of food-derived phytochemicals and other diet-associated compounds or their synthetic derivatives represent a cornucopia of potential new compounds for prevention and treatment of chronic or acute diseases. Many have entered clinical practice or are under clinical testing. A remarkable property shared by several phytochemicals is the capacity to restrain inflammation and angiogenesis, two complex physiologic processes kept under control by strict rules, which can backfire in cancer and in pathologic conditions such as metabolic, cardiovascular and neurological disorders. We termed this concept "angioprevention". Here, we discuss recent findings on the metabolic effects of several phytochemicals with anticancer properties. The different molecular targets shared by these compounds seem to converge on crosstalking signaling networks involved in controlling energy metabolism through a redox-regulated code. The redox imbalance produced in the tissue microenvironment elicits an adaptive response that seems to provide cytoprotective effects potentially beneficial in cardiovascular and neurological disorders or energy balancing effects in metabolic disorders. However, in transformed and overt tumor cells, this redox imbalance favors cell death while curbing tumor inflammation and angiogenesis, thus engaging an overall antitumor response. These concepts provide a broader framework for pharmacological application of phytochemical-derived drugs against cancer.

Angiostatin anti-angiogenesis requires IL-12: the innate immune system as a key target

BACKGROUND

Angiostatin, an endogenous angiogenesis inhibitor, is a fragment of plasminogen. Its anti-angiogenic activity was discovered with functional assays in vivo, however, its direct action on endothelial cells is moderate and identification of definitive mechanisms of action has been elusive to date. We had previously demonstrated that innate immune cells are key targets of angiostatin, however the pathway involved in this immune-related angiogenesis inhibition was not known. Here we present evidence that IL-12, a principal TH1 cytokine with potent anti-angiogenic activity, is the mediator of angiostatin's activity.

METHODS

Function blocking antibodies and gene-targeted animals were employed or in vivo studies using the subcutaneous matrigel model of angiogenesis. Quantitative real-time PCR were used to assess modulation of cytokine production in vitro.

RESULTS

Angiostatin inhibts angiogenesis induced by VEGF-TNFalpha or supernatants of Kaposi's Sarcoma cells (a highly angiogenic and inflammation-associated tumor). We found that function-blocking antibodies to IL-12 reverted angiostatin induced angiogenesis inhibition. The use of KO animal models revealed that angiostatin is unable to exert angiogenesis inhibition in mice with gene-targeted deletions of either the IL-12 specific receptor subunit IL-12Rbeta2 or the IL-12 p40 subunit. Angiostatin induces IL-12 mRNA synthesis by human macrophages in vitro, suggesting that these innate immunity cells produce IL-12 upon angiostatin stimulation and could be a major cellular mediator.

CONCLUSION

Our data demonstrate that an endogenous angiogenesis inhibitor such as angiostatin act on innate immune cells as key targets in inflammatory angiogenesis. Angiostatin proves to be anti-angiogenic as an immune modulator rather than a direct anti-vascular agent. This article is dedicated to the memory of Prof Judah Folkman for his leadership and for encouragement of these studies.

Anti-angiogenic activity of a novel class of chemopreventive compounds: oleanic acid terpenoids

Angiogenesis is the base for solid tumour growth and dissemination, and anti-angiogenic drugs have been demonstrated to be active in clinical trials. In addition, it has become increasingly clear that inflammation is a key component in tumour insurgence. Chemoprevention focuses on the primary or secondary prevention of cancer using natural or synthetic agents that usually show mild or no collateral effects. We have noted that angiogenesis, particularly 'inflammatory angiogenesis', is a common target of many chemopreventive molecules, where they most likely suppress the angiogenic switch in pre-malignant tumours, a concept we have termed 'angioprevention'. We have shown that various molecules, such as flavonoids, antioxidants and retinoids, act in the tumour microenvironment inhibiting the recruitment and/or activation of endothelial cells and phagocytes of the innate immunity. We have recently assessed the activity of novel compounds derived from the oleanolic acid triterpenoid, called CDDO-Me and CDDO-Imm. These compounds show a potent anti-angiogenic activity at low dosages. In vivo they inhibit angiogenesis in the Matrigel sponge assay and in KS-Imm (an immortalized Kaposi's sarcoma cell line) tumour growth. In vitro they are able to prevent endothelial cell tubulogenesis when cultured on Matrigel. In human umbilical vein endothelial (HUVE) cells these compounds can inhibit the activation of the extracellular signal-regulated kinase ERK1/2 pathway after stimulation with vascular endothelial growth factor (VEGF). Moreover, from immunofluorescence experiments we observed that treatment with these triterpenoids prevents nuclear factor NF-kappaB translocation into the nucleus and thereby the activation of downstream pathways. The particularly potent anti-angiogenic activity seen in vivo suggest that CDDO-Me may be interacting with an important network of molecular and cellular targets, on endothelial cells, and could be employed for 'angioprevention'. These substances are being assessed in phase I trials in humans in the United States.

Inflammation, inflammatory cells and angiogenesis: decisions and indecisions

Endothelial-immune cell cross-talk goes well beyond leukocyte and lymphocyte trafficking, since immune cells are able to intimately regulate vessel formation and function. Here we review the evidence that most immune cells are capable of polarization towards a dichotomous activity either inducing or inhibiting angiogenesis. In addition to the well-known roles of tumor associated macrophages, we find that neutrophils, myeloid-derived suppressor and dendritic cells clearly have the potential for influencing tumor angiogenesis. Further, the physiological functions of NK cells suggest that these cells may also show a potentially important role in pro- or anti-angiogenesis regulation within the tumor microenvironment. At the same time many angiogenic factors influence the activity and function of immune cells that generally favor tumor survival and tolerance. Thus the immune system itself represents a major pharmaceutical target and links angiogenesis inhibition to immunotherapy.

In vivo isolation and characterization of stem cells with diverse phenotypes using growth factor impregnated biomatrices

Background

The stimulation to differentiate into specific cell types for somatic stem cells is largely due to a series of internal and external signals coming from the microenvironment that surrounds the stem cell. Even though intensive research has been made, the basic mechanisms of plasticity and/or the molecules regulating stem cells proliferation and differentiation are not completely determined. Potential answers concerning the problems could be derived from the studies of stem cells in culture.

Methodology/Principle Findings

We combine a new procedure (using the matrigel biopolymer supplemented with a selected cytokine/growth factor) with classic techniques such as light, confocal and electron microscopy, immunohistochemistry and cell culture, to perform an analysis on stem cells involved in the leech (Hirudo medicinalis) repair tissues. The leech has a relative anatomical simplicity and is a reliable model for studying a variety of basic events, such as tissue repair, which has a striking similarity with vertebrate responses. Our data demonstrate that the injection of an appropriate combination of the matrigel biopolymer supplemented with a selected cytokine/growth factor in the leech Hirudo medicinalis is a remarkably effective tool for isolating a specific cell population in vivo. A comparative analysis of biopolymer in vivo sorted stem cells indicates that VEGF recruited cells of a hematopoietic/endothelial phenotype whereas MCP-1/CCL2 isolated cells that were of an early myeloid lineage.

Conclusion

Our paper describes, for the first time, a method allowing not only the isolation of a specific cell population in relation to the cytokine utilized but also the possibility to culture a precise cell type whose isolation is otherwise quite difficult. This approach could be broadly applied to isolate stem cells of diverse origins based on the recruitment stimuli employed.

Endothelial cell aging and apoptosis in prevention and disease: E-selectin expression and modulation as a model

Endothelial cell senescence and apoptosis are features of numerous human pathologies including atherosclerosis, allograft vasculopathy, heart failure, diabetic retinopathy and scleroderma. In contrast, endothelial cell activation and replication associated with vessel proliferation and angiogenesis are now therapeutic targets in other diseases such as cancer and macular dystrophy. Finally, preventive medicine, in particular cardiovascular and cancer chemoprevention, commonly involve the endothelium. Here we discuss several aspects of the interplay between endothelial cell aging, apoptosis and senescence. Further, we show novel microarray data on endothelial cells "aged" in culture, and note that many genes regulated by the aging process are also modulated by a chemopreventive anti-angiogenic and anti-apoptotic drug, N-acetyl-cysteine (NAC). Focusing on one of these genes, the leukocyte adhesion protein E-selectin, we show that E-selectin is down-modulated with time in culture and upon treatment with NAC at mRNA and protein levels. This correlates with reduced adhesion of breast cancer cells and NF-kB activation in NAC treated endothelial cells. These data underscore the effects of a chemoprevention agent in modulating parameters associated with endothelial cell aging.

The synthetic oleanane triterpenoid, CDDO-methyl ester, is a potent antiangiogenic agent

We show that the synthetic oleanane triterpenoid, CDDO-methyl ester (CDDO-Me; methyl 2-cyano-3,12-dioxoolean-1,9-dien-28-oate) is an effective agent for suppressing angiogenesis, both in cell culture and in vivo. The potency of CDDO-Me is particularly striking when dosed in vivo to inhibit the angiogenic effects of vascular endothelial growth factor and tumor necrosis factor-alpha in Matrigel sponge assays; activity is seen at i.p. doses of CDDO-Me as low as 0.003 mg/kg of body weight. If the Matrigel sponges are impregnated with CDDO-Me just before implantation in the mice, picomolar doses of CDDO-Me will suppress angiogenesis. CDDO-Me also inhibits growth of endothelial cells in monolayer cultures and suppresses neovascular morphogenesis in three-dimensional cultures, but significantly higher doses (50-200 nmol/L) are required. We also show antiangiogenic effects of CDDO-Me on xenografts of Kaposi's sarcoma cells in immunocompromised mice, using CD31 as a marker. Several known individual molecular targets of CDDO-Me and related triterpenoids that are relevant to all of these findings include nuclear factor-kappaB signaling, signal transducers and activators of transcription signaling, and transforming growth factor-beta signaling, as well as Keap1, the endogenous inhibitor of the transcription factor Nrf2. However, the particularly potent antiangiogenic activity seen in vivo in the present experiments suggest that CDDO-Me, as an angioprevention agent, may be interacting with an entire network of molecular and cellular targets, rather than at a single molecular locus or in a single-cell type.

Experimental therapeutic approaches to adenocarcinoma: the potential of tumor cells engineered to express MHC class II molecules combined with naked DNA interleukin-12 gene transfer

We have previously shown that TS/A murine mammary adenocarcinoma cells, induced to express high surface expression of MHC class II molecules by stable transfection of CIITA, resulted in high rate (92%) of tumor rejection and tumor immunity to subsequent homologous tumor challenges. The immunological basis of tumor response is based on tumor-specific CD4(+) T helper type 1 (Th1) in the priming phase and tumor-specific CD8(+) T cells as the major effector cells. IL-12 is the crucial cytokine that drives Th1 polarization in conjunction with inducing strong cellular-based immune responses. We have previously shown in the same tumor model that a naked DNA IL-12 gene transfer was effective in preventing tumor angiogenesis in an immunopreventive approach when administrated at least 2 days prior to the tumor inoculation. Here we indicate that the combination of the two approaches in immunotherapy of established tumors is efficacious in delaying tumor growth but not in completely eradicating the tumor.

Molecular pathways for cancer angioprevention

By analogy to the success of cardiovascular medicine in reducing mortality through preventive measures, cancer chemoprevention has the potential to significantly reduce incidence and mortality due to tumors. Angiogenesis is an event inhibited by most of the promising cancer chemoprevention compounds, a concept we termed "angioprevention." Here, we review the signaling pathways that are targeted by diverse angioprevention compounds in endothelial cells. We highlight diverse mechanisms of action, implying that combination angioprevention approaches could further improve efficacy and be transferred to clinical practice.

Biosynthesis and structure of the basement membrane proteoglycan containing heparan sulphate side-chains

Endothelial, epithelial and muscle cells produce a similar proteoglycan for deposition in basement membrane. This proteoglycan is initially synthesized as a low buoyant density proteoglycan containing 3-5 heparan sulphate side-chains (15,000-65,000 Mr each), along one half of a 400,000 Mr core protein. A portion of the population of these macromolecules is degraded to produce small high density proteoglycans containing a variable-sized core protein less than 100,000 in Mr. This biosynthetic and degradative process probably accounts for the variety of differently sized heparan sulphate proteoglycans that have been isolated from various basement membrane sources.

Effects of IL-12 gene therapy on spontaneous transgenic and transplanted breast tumors

Cytokines are promising agents for cancer therapy due to their activity at low concentrations. We used a naked IL-12 DNA expression vector to achieve long-term systemic cytokine expression to inhibit breast tumor growth in MMTVneu transgenic and transplanted models. Constant low levels of IL-12 produced by this protocol provided effective tumor growth inhibition of both tumor models without adverse effects.

Inhibition of a vascular ocular tumor growth by IL-12 gene transfer

Ocular tumors such as retinoblastoma and uveal melanoma have devastating effects on vision. Patients with uveal melanoma also have low 5-year survival rates, thus new therapeutic modalities are necessary. As both retinoblastoma and uveal melanoma are highly vascular, we tested application of a gene transduction approach with a potent TH1 cytokine also endowed with strong anti-angiogenic activity, Interleukin-12 (IL-12). Gene transfer into murine 99E1 uveal melanoma-like cells, while having no effects on growth in vitro, essentially blocked subcutaneous tumor growth in vivo without evident signs of toxicity. Orthotopic intraocular injection resulted in invasive tumors that destroyed ocular architecture by the control cells while the IL-12 transduced cells rarely formed tumors. Histological analysis revealed highly invasive and angiogenic tumor growth in the controls and poorly vascularized tumors in the presence of IL-12. The tumor repression effect could be reproduced by a systemic anti-angiogenic effect, where controlateral injection of IL-12 expressing cells strongly repressed growth in tumors formed by parental 99E1 cells. This was associated with significantly lowered tumor vessel densities, a trend toward lower VEGF levels in the lesion, and significantly decreased NK cells in the parental tumors exposed to systemic IL-12. Taken together, our data suggest that IL-12 gene transfer can provide anti-angiogenic effects without toxicity and may be particularly suited for therapy of vascularized ocular tumors.

Novel cell death pathways induced by N-(4-hydroxyphenyl)retinamide: therapeutic implications

We previously reported that N-(4-hydroxyphenyl)retinamide (4HPR) inhibits retinoblastoma tumor growth in a murine model in vivo and kills Y79 retinoblastoma cells in vitro. In this work, we assayed different cell death-related parameters, including mitochondrial damage and caspase activation, in Y79 cells exposed to 4HPR. 4HPR induced cytochrome c release from mitochondria, caspase-3 activation, and oligonucleosomal DNA fragmentation. However, pharmacologic inactivation of caspases by the pan-caspase inhibitor BOC-D-fmk, or specific caspase-3 inhibition by Z-DEVD-fmk, was not sufficient to prevent cell death, as assessed by loss of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction, lactate dehydrogenase release, disruption of mitochondrial transmembrane potential (Deltapsi(m)), and ATP depletion. We found that 4HPR causes lysosomal membrane permeabilization and cytosolic relocation of cathepsin D. Pepstatin A partially rescued cell viability and reduced DNA fragmentation and cytosolic cytochrome c. The antioxidant N-acetylcysteine attenuated cathepsin D relocation into the cytosol, suggesting that lysosomal destabilization is dependent on elevation of reactive oxygen species and precedes mitochondrial dysfunction. Activation of AKT, which regulates energy level in the cell, by the retinal survival facto]r insulin-like growth factor I was impaired and insulin-like growth factor I was ineffective against ATP and Deltapsi(m) loss in the presence of 4HPR. Lysosomal destabilization, associated with mitochondrial dysfunction, was induced by 4HPR also in other cancer cell lines, including PC3 prostate adenocarcinoma and the vascular tumor Kaposi sarcoma KS-Imm cells. The novel finding of a lysosome-mediated cell death pathway activated by 4HPR could have implications at clinical level for the development of combination chemoprevention and therapy of cancer.

Identification of genes selectively regulated by IFNs in endothelial cells

IFNs are highly pleiotropic cytokines also endowed with marked antiangiogenic activity. In this study, the mRNA expression profiles of endothelial cells (EC) exposed in vitro to IFN-alpha, IFN-beta, or IFN-gamma were determined. We found that in HUVEC as well as in other EC types 175 genes were up-regulated (>2-fold increase) by IFNs, including genes involved in the host response to RNA viruses, inflammation, and apoptosis. Interestingly, 41 genes showed a >5-fold higher induction by IFN-alpha in EC compared with human fibroblasts; among them, the gene encoding the angiostatic chemokine CXCL11 was selectively induced by IFN-alpha in EC along with other genes associated with angiogenesis regulation, including CXCL10, TRAIL, and guanylate-binding protein 1. These transcriptional changes were confirmed and extended by quantitative PCR analysis and ELISA; whereas IFN-alpha and IFN-beta exerted virtually identical effects on transcriptome modulation, a differential gene regulation by type I and type II IFN emerged, especially as far as quantitative aspects were concerned. In vivo, IFN-alpha-producing tumors overexpressed murine CXCL10 and CXCL11, guanylate-binding protein 1, and TRAIL, with evidence of CXCL11 production by tumor-associated EC. Overall, these findings improve our understanding of the antiangiogenic effects of IFNs by showing that these cytokines trigger an antiangiogenic transcriptional program in EC. Moreover, we suggest that quantitative differences in the magnitude of the transcriptional activation of IFN-responsive genes could form the basis for cell-specific transcriptional signatures.

Angiogenesis and cancer prevention: a vision

Angiogenesis is necessary for solid tumor growth and dissemination. In addition to angiogenesis, it has become increasingly clear that inflammation is a key component in cancer insurgence that can promote tumor angiogenesis. We noted that angiogenesis is a common and key target of most chemopreventive molecules, where they most likely suppress the angiogenic switch in premalignant tumors, a concept we termed angioprevention. We have shown that various molecules, such as flavonoids, antioxidants, and retinoids, act in the tumor microenvironment, inhibiting the recruitment and/or activation of endothelial cells and phagocytes of the innate immunity. N-acetyl-cysteine, and the green tea flavonoid epigallocatechin-3-gallate (EGCG) and the beer/ hops-derived chalcone Xanthohumol all prevent angiogenesis in the Matrigel sponge angiogenic assay in vivo and inhibit the growth of the highly angiogenic Kaposi's sarcoma tumor cells (KS-Imm) in nude mice. The synthetic retinoid 4-hydroxyfenretinide (4HPR) also shows anti-angiogenic effects. We analyzed the regulation of gene expression they exert in primary human umbilical endothelial cells (HUVEC) in culture with functional genomics. Expression profiles obtained through Affymetrix GeneChip arrays identified overlapping sets of genes regulated by anti-oxidants. In contrast, the ROS-producing 4HPR induced members of the TGFbeta-ligand superfamily, which, at least in part, explains its anti-angiogenic activity. NAC and the flavonoids all suppressed the IkB/NF-kappaB signaling pathway even in the presence of NF-kappaB stimulation by TNFalpha, and showed reduced expression of many NF-kappaB target genes. A selective apoptotic effect on transformed cells, but not on endothelial cells, of the anti-oxidants may be related to the reduced expression of the NF-kappaB-dependent survival factors Bcl2 and Birc5/surviving, which are selectively overexpressed in transformed cells by these factors. The repression of the NF-kappaB pathway suggests anti-inflammatory effects for the antioxidant compounds that may also represent an indirect role in angiogenesis inhibition. The green tea flavonoid EGCG does target inflammatory cells, mostly neutrophils, and inhibits inflammation-associated angiogenesis. The other angiopreventive molecules are turning out to be effective modulators of phagocyte recruitment and activation, further linking inflammation and vascularization to tumor onset and progression and providing a key target for cancer prevention.

Marine sponge-derived polymeric alkylpyridinium salts as a novel tumor chemotherapeutic targeting the cholinergic system in lung tumors

Previous studies have shown that the cholinergic system plays a pivotal rule in small cell lung cancer (SCLC) cell growth through an autocrine loop that activates the nicotinic cholinergic receptor, which together with the activation of this receptor by nicotine links SCLC evolution with tobacco use. Non-small cell lung cancer (NSCLC) is the most common form of lung cancer and is also linked to tobacco use. Here we describe the presence of molecules of the cholinergic system in NSCLC samples and cell lines and investigate the implications of the cholinergic system in cell growth regulation. Cholino-acetyltransferase (ChAT), vesicular acetylcholine transporter (VAChT) and acetylcholinesterase (AChE) were observed in NSCLC tumor biopsies and in NSCLC cell lines. Polymeric alkylpyridinium salts (poly-APS) are AChE inhibitors isolated from the crude extract of the marine sponge, Reniera sarai. These metabolites were characterized as a mixture of two polymers of 3-octylpyridinium, including 29 and 99 monomeric units. Exposure of normal lung fibroblast and NSCLC cell lines to poly-APS revealed a selective cytotoxicity for cancer cells as compared to the normal fibroblast cell lines. FACS analysis indicated poly-APS induced apoptosis in NSCLC cells but not in normal lymphocytes. Non-toxic doses of poly-APS also potently reduced NSCLC cell-cell adhesion in suspension cultures. The limited toxicity of poly-APS on normal cells was confirmed by injection in the caudal vein of mice. No overt effects on health parameters, such as weight gain and physical behavior, were observed, and histological analysis of major organs did not reveal differences between the treated animals as compared to controls. These data demonstrate that NSCLC cells express cholinergic molecules that may be involved in cell growth regulation and that the cholinesterase inhibitor, poly-APS, shows selective toxicity toward NSCLC cells while having no apparent toxicity towards normal cells and tissue in vitro and in vivo.

Biological assays and genomic analysis reveal lipoic acid modulation of endothelial cell behavior and gene expression

Lipoic acid (LA) is a sulfated antioxidant produced physiologically as a coenzyme of the pyruvate dehydrogenase complex; it is currently used for treatment of non-insulin-dependent diabetes to favor the cellular uptake of glucose. We have previously described the angiopreventive potential of molecules sharing common features with LA: N-acetyl cysteine, epigallocatechin-3-gallate and xanthohumol. To expand these studies, we have tested the capacity of LA to modulate angiogenesis in tumor growth using a Kaposi's sarcoma model. Endothelial cells exposed to LA displayed a dose-dependent reduction of cell migration and a time-dependent modulation of the phosphorylation of key signaling molecules. In vivo, LA efficiently repressed angiogenesis in matrigel plugs and KS-Imm tumor growth. We analyzed modulation of gene expression in endothelial cells treated with LA for 5 h (early response), finding a mild anti-apoptotic, antioxidant and anti-inflammatory response. A group of LA-targeted genes was selected to perform real-time polymerase chain reaction time-lapse experiments. The long-term gene regulation (48 h and 4 days) shows higher rates of modulation as compared with the array data, confirming that LA is able to switch the regulation of several genes linked to cell survival, inflammation and oxidative stress. LA induced the production of tumor necrosis factor-alpha-related apoptosis-inducing ligand (TRAIL) in KS-Imm and activin-A in KS-Imm and endothelial cells; these factors show anti-angiogenic activity in vivo contributing to explain the inhibitory effect of LA on neovascularization. According to our data, LA has promising anti-angiogenic properties, though its influence on central metabolic pathways should suggest more caution about its widespread and not prescribed use at pharmacological doses.

Growth Factors and Chemokines: A Comparative Functional Approach Between Invertebrates and Vertebrates

Growth factors and cytokines control and coordinate a broad spectrum of fundamental cellular functions, and are evolutionarily conserved both in vertebrates and invertebrates. In this review, we focus our attention on the functional phylogenetic aspects of growth factors/cytokines like the Transforming Growth Factor-beta (TGF-beta), the Connective Tissue Growth Factor (CTGF), and the Vascular Endothelial Growth Factor (VEGF). We will also delve into the activites of two chemokine families, interleukin (IL)-8 (or CXCL8) and CC chemokine ligand 2/monocyte chemoattractant protein-1 (CCL2). These molecules have been selected for their involvement in immune responses and wound healing processes, where they mediate and finely regulate various regeneration processes like angiogenesis or fibroplasia, not only in vertebrates, but also in invertebrates.

Cytokines and chemokines as regulators of angiogenesis in health and disease

The intricate interplay between the endothelium and immune cells has been well recognized in the context of immune responses. However, the fact that this inter-relation extends well beyond immune regulation is becoming increasingly recognized, with particular regards to the influence of the immune system on the essential endothelial process of angiogenesis, where the contribution of cytokines drives the angiogenic process. As angiogenesis is an important component of numerous pathological states, among these chronic inflammatory conditions and cancer, understanding the role of cytokines and chemokines in guiding new vessel formation provides key insight into novel therapeutic modalities. Here we review the actions of principal cytokines and chemokines on the angiogenic process and discuss how both can be considered potential pharmaceutical targets or pharmaceuticals themselves for modulation of angiogenesis in chronic inflammation associated with cancer, rheumatoid arthritis and other inflammatory diseases.