Durable recovery of the macular architecture and functionality of a diagnosed age-related macular degeneration 1 year after a single intravitreal injection of dobesilate.

Among the age-related diseases that affect vision, age-related macular degeneration is the most frequent cause of blindness in patients older than 60 years. In this communication, we report the full anatomical and functional recovery of a patient diagnosed with wet age-related macular degeneration 1 year after a single intravitreal injection of dobesilate.

Treatment of dry age-related macular degeneration with dobesilate.

The authors present anatomical and functional evidences of dry age-macular degeneration improvement, after intravitreal treatment with dobesilate. Main outcomes measures were normalisation of retinal structure and function, assessed by optical coherence tomography, fundus-monitored microperimetry, electrophysiology and visual acuity. The effect might be related to the normalisation of the outer retinal architecture.

Topical treatment of actinic keratoses with potassium dobesilate 5% cream. a preliminary open-label study.

BACKGROUND: Fibroblast growth factor (FGF) is involved in skin tumorigenesis: it promotes cell viability, induces angiogenesis and stimulates invasiveness. Dobesilate is a drug that blocks the activity of FGF. The primary objective was to evaluate the efficacy and tolerability of potassium dobesilate 5% cream in the treatment of actinic keratoses. METHODS: Potassium dobesilate 5% cream was applied twice daily for 16 weeks to actinic keratosis lesions in 30 patients. The lesions were evaluated clinically at an initial baseline visit, at intermediate visits, and at 16 weeks of treatment. - RESULTS: The use of potassium dobesilate 5% cream for 16 weeks induced complete regression in 70% of evaluated actinic keratoses, corresponding to grade I, II and III clinical variants, and a partial response (at least 75% reduction of lesions) in 20% of the cases. CONCLUSION: Our preliminary trial shows that potassium dobesilate exerts anti-tumorigenic effects and may play a useful role in the chemoprevention of skin cancers.

Dobesilate inhibits the activation of signal transducer and activator of transcription 3, and the expression of cyclin D1 and bcl-XL in glioma cells.

OBJECTIVES: Because fibroblast growth factor (FGF) causes the intracellular accumulation of activated signal transducer and activator of transcription 3 (STAT3), we assessed whether dobesilate, a synthetic FGF inhibitor that has been reported to show antiproliferative and proapoptotic activities in glioma cell cultures, down-regulates the STAT3 signaling pathway in growing cultures of those cells. Because STAT3 signaling pathway plays pleiotropic roles in tumor proliferation, maintenance of STAT3 in its inactive state may prevent glioma growth and spreading. METHODS: Rat glioma C6 cells were treated with dobesilate and cultures were evaluated immunocytochemically for STAT3 activation and enhancement of the expression rate of cyclin D1 and bcl-XL. RESULTS: Dobesilate abrogates the accumulation of activated STAT3 in glioma cells. The decrease in the intracellular levels of activated STAT3 by the dobesilate treatment runs parallel with a significant attenuation of cyclin D1 and bcl-XL expression. CONCLUSION: Treatment with inhibitors of FGF down-regulates the STAT3 signaling pathway. These alterations could be correlated to the already observed inhibition of cell proliferation and promotion of apoptosis in glioma cell cultures by dobesilate. The reported results may open new avenues for developing new treatments against these tumors.

Dobesilate diminishes activation of the mitogen-activated protein kinase ERK1/2 in glioma cells.

Fibroblast growth factors (FGFs) and their receptors, regularly expressed at high levels in gliomas, are further upregulated during the transition of the tumor from low- to high-grade malignancy, and are essential for glioma progression. FGFs induce upregulation of the mitogen-activated protein kinase (MAPK) signaling cascade in cultured glioma cells, which suggests that MAPK pathway participates in the FGF-dependent glioma development. Recently, it has been shown that dobesilate, an inhibitor of FGF mitogenic activity, shows antiproliferative and proapoptotic activities in glioma cell cultures. Accordingly, it should be expected this new synthetic FGF inhibitor to affect the activation levels of MAPK. Here we report that immunocytochemical and Western blot data unequivocally show that treatment of cell cultures with dobesilate causes a significant decrease of the intracellular levels of ERK1/2 activation, one of the components of the MAPK signalling cascade. This finding supports an important role for dobesilate in glioma growth, suggesting that dobesilate should be a treatment to be born in mind for glioma management.

Dihydroxy-2,5 benzenesulphonate (dobesilate) elicits growth arrest and apoptosis in glioma cells.

OBJECTIVES: Dihydroxy-2,5 benzenesulphonate (dobesilate) is used as an oral agent for treatment of vascular complications of diabetic retinopathy. We previously showed that blockade of fibroblast growth factor (FGF) driving angiogenesis with dobesilate inhibited new blood vessel formation in a mouse gelatine plug assay. In the present study we assessed the effects of dobesilate in rat glioma cells. METHODS: Rat C6 cells line were grown as adherent cells in Dulbecco modified Eagle medium supplemented with 1% (v/v) fetal bovine serum and antibiotics. Calcium dobesilate was added in independent experiments at the following concentrations: 10, 25, 50, 75 and 100 microM, and cells were incubated for 24 hours. Effects of dobesilate in glioma cell proliferation and survival were assessed using crystal violet staining and TUNEL assay, respectively. RESULTS: Incubation of glioma cells with dobesilate for 24 hours concentration-dependently decreased cell proliferation with an apparent IC50 of 25 microM, and this antiproliferative effect was related to a significant increase in glioma cell apoptosis. CONCLUSIONS: The results suggest that dobesilate is a promising candidate leading to the development of a new adjuvant therapeutic strategy for gliomas.

Dobesilate is an angiogenesis inhibitor.

Aberrant angiogenesis is essential for the progression of solid tumors and hematological malignancies. Antiangiogenic therapy is one of the most promising approaches to treat such diseases. Dobesilate is an oral agent for treatment of vascular complications of diabetic retinopathy. We have examined the possibility that this compound could interfere with the process of angiogenesis in a mouse gelatine sponge assay using acidic fibroblast growth factor (aFGF) as an inducer of neovascularization. According to the results reported here, dobesilate remarkably reduced vessel ingrowth in aFGF-containing subcutaneous sponges in mice. These findings suggest that dobesilate could be an effective agent in the treatment of angiogenesis-dependent diseases involving FGFs.

Identification and characterization of the peptidic component of the immunomodulatory glycoconjugate Immunoferon.

Inmunoferon is a glycoconjugate of natural origin, formed by the noncovalent association of a protein from Ricinus communis and a polysacharidic moiety, and endowed with immunomodulatory as well as pharmacological activities. This study investigated the nature of polypeptidic component of Inmunoferon. Through biochemical procedures and comparison with protein databases, the isolated protein was identified as the processed form of the seed of Ricinus communis 2S storage polypeptide, which has been termed RicC3. Further analysis of the isolated protein has revealed that it is composed of two different subunits, alpha and beta, which form an heterodimer of high stability and resistance to denaturation, acidic pH and proteolytic cleavage. These findings confirm the excellent properties of the product after oral administration and provide additional support for the pharmacological activities of Inmunoferon.

A novel solenoid fold in the cell wall anchoring domain of the pneumococcal virulence factor LytA.

Choline binding proteins are virulence determinants present in several Gram-positive bacteria. Because anchorage of these proteins to the cell wall through their choline binding domain is essential for bacterial virulence, their release from the cell surface is considered a powerful target for a weapon against these pathogens. The first crystal structure of a choline binding domain, from the toxin-releasing enzyme pneumococcal major autolysin (LytA), reveals a novel solenoid fold consisting exclusively of beta-hairpins that stack to form a left-handed superhelix. This unique structure is maintained by choline molecules at the hydrophobic interface of consecutive hairpins and may be present in other choline binding proteins that share high homology to the repeated motif of the domain.

Abolished angiogenicity and tumorigenicity of rat glioma by 1-naphthalenemonosulfonate.

Suramins and suradistas, an important group of potential anti-cancer agents, inhibit fibroblast growth factor (FGF) mitogenic activity. It has been shown that naphthalenesulfonates, with a common chemical function to the family of suramins and suradistas, mimic their inhibitory activity, abolishing FGF-induced angiogenesis in vivo, and inducing apoptosis of C6 glioma cells in culture. In the present report, we show that intratumoral administration of 1-naphthalenemonosulfonate induces a considerable regression of gliomas in rats, significantly enhances apoptosis, and attenuates tumor angiogenesis. These findings may lead to new approaches for the treatment of glioblastoma, a most common primary malignant brain tumor of very poor prognosis, as well as of other angiogenesis-dependent malignancies.

Sequence analysis of heparan sulfate epitopes with graded affinities for fibroblast growth factors 1 and 2.

Proteins that belong to the fibroblast growth factor (FGF) family regulate proliferation, migration, and differentiation of many cell types. Several FGFs, including the prototype factors FGF-1 and FGF-2, depend on interactions with heparan sulfate (HS) proteoglycans for activity. We have assessed tissue-derived HS fragments for binding to FGF-1 and FGF-2 to identify the authentic saccharide motifs required for interactions. Sequence information on a range of N-sulfated HS octasaccharides spanning from low to high affinity for FGF-1 was obtained. All octasaccharides with high affinity for FGF-1 (> or =0.5 m NaCl required for elution) contained an internal IdoUA(2-OSO(3))-GlcNSO(3)(6-OSO(3))-IdoUA(2-OSO(3))-trisaccharide motif. Octasaccharides with a higher overall degree of sulfation but lacking the specific trisaccharide motif showed lower affinity for FGF-1. FGF-2 was shown to bind to a mono-O-sulfated HS 6-mer carrying a single internal IdoUA(2-OSO(3))-unit. However, a di-O-sulfated -IdoUA(2-OSO(3))-GlcNSO(3)-IdoUA(2-OSO(3))-trisaccharide sequence within a HS 8-mer gave stronger binding. These findings show that not only the number but also the positions of individual sulfate groups determine affinity of HS for FGFs. Our findings support the notion that FGF-dependent processes can be modulated in vivo by regulated expression of distinct HS sequences.

Solution structure and interaction with basic and acidic fibroblast growth factor of a 3-kDa human platelet factor-4 fragment with antiangiogenic activity.

Platelet factor-4 is a protein belonging to the family of ELR-negative CXC chemokines which binds to fibroblast growth factor and inhibits its mitogenic activity. Platelet factor-4 also inhibits tumor growth by mechanisms involving antiangiogenesis. Antiangiogenic activity in vitro has also been shown for the 24-residue C-terminal fragment of the protein, which decreases the affinity between basic fibroblast growth factor and its cell-surface receptor. In this study, the preferential conformation of this fragment in solution has been determined and has been found to be composed of two helical subdomains. In addition, we show that the fragment forms a specific 1:1 complex with acidic and basic fibroblast growth factors and that both subdomains are probably required for inhibition of fibroblast growth factor-driven mitogenesis. Finally, we show that the binding of the fragment alters the structure of the fibroblast growth factors, although some of such alterations do not seem related with the inhibition of mitogenic activity. Since this fragment has recently been shown to inhibit fibroblast growth factor-induced angiogenesis in vivo when injected intraperitoneally, these results are relevant for developing new antiangiogenic treatments.

Myo-inositol hexasulphate and low molecular weight heparin binding to human acidic fibroblast growth factor: a calorimetric and FTIR study.

The interaction of an amino-terminal-truncated 139 amino-acids form of human acidic fibroblast growth factor with myo-inositol hexasulphate and low molecular weight (3500 g mol(-1)) heparin has been studied by isothermal titration calorimetry, differential scanning calorimetry and Fourier transform infrared spectroscopy. A slightly higher affinity for the monosaccharide has been measured. The binding of the ligands causes an increase of 13--15 degrees C in the melting temperature of the free protein (45 degrees C). From measured enthalpy and heat capacity changes, calculations of changes in accessible surface areas have been made. These calculations, together with infrared spectroscopy data, indicate that a small conformational change is induced by the binding of both ligands. This conformational change would affect the tertiary structure, not the secondary one.

A short peptide domain of platelet factor 4 blocks angiogenic key events induced by FGF-2.

Platelet factor 4 (PF-4) is a CXC-chemokine with strong anti-angiogenic properties. We have shown previously that PF-4 inhibits angiogenesis by associating directly with fibroblast growth factor 2 (FGF-2), inhibiting its dimerization, and blocking FGF-2 binding to endothelial cells. We now have characterized a small peptide domain (PF-447-70) derived from the C-terminus of PF-4, which conserves anti-angiogenic effects of the parent protein. PF-447-70 inhibited internalization of 125I-FGF-2 by endothelial cells in a time-dependent manner. The peptide reduced FGF-2-stimulated cell migration to control levels in wounded monolayers of bovine capillary endothelial cells. PF-447-70 also reduced FGF-2 induced phosphorylation of MAP kinases ERK-1 and ERK-2, which are essential for migration and survival of endothelial cells. In a serum-free ex vivo angiogenesis assay, the peptide blocked microvessel outgrowth by 89%. A single amino acid substitution within PF-447-70 abolished all inhibitory activities. To simulate a real anti-angiogenic treatment situation, we administered PF-447-70 systemically to mice implanted subcutaneously with FGF-2 containing gelatin sponges with the result of sparse, scattered, and immature vessel growth. The small peptide fragment derived from the angio-inhibitory CXC-chemokine PF-4 might be used as a starting point to develop anti-angiogenic designer drugs for angiogenesis-dependent pathologies such as cancer, diabetic retinopathy, and rheumatoid arthritis.

Fibroblast growth factors in myocardial ischemia / reperfusion injury and ischemic preconditioning.

Angiogenic growth factors such as fibroblast growth factors (FGFs) are currently in clinical trials for accelerating blood vessel formation in myocardial and limb ischemic conditions. However, recent experimental evidence suggests that FGFs can also participate as endogenous cardioprotective agents. In this report, the current knowledge for FGFs implication in myocardial ischemic tolerance will be summarized. Pharmacologic preconditioning with drugs as FGFs that mimic the beneficial effects of ischemic preconditioning could lead to novel therapeutic approaches for the treatment of ischemic disorders including myocardial infarction and stroke.

The activation of fibroblast growth factors by heparin: synthesis, structure, and biological activity of heparin-like oligosaccharides.

An effective strategy has been designed for the synthesis of oligosaccharides of different sizes structurally related to the regular region of heparin; this is illustrated by the preparation of hexasaccharide 1 and octasaccharide 2. This synthetic strategy provides the oligosaccharide sequence containing a D-glucosamine unit at the nonreducing end that is not available either by enzymatic or chemical degradation of heparin. It may permit, after slight modifications, the preparation of oligosaccharide fragments with different charge distribution as well. NMR spectroscopy and molecular dynamics simulations have shown that the overall structure of 1 in solution is a stable right-hand helix with four residues per turn. Hexasaccharide 1 and, most likely, octasaccharide 2 are, therefore, chemically well-defined structural models of naturally occurring heparin-like oligosaccharides for use in binding and biological activity studies. Both compounds 1 and 2 induce the mitogenic activity of acid fibroblast growth factor (FGF1), with the half-maximum activating concentration of 2 being equivalent to that of heparin. Sedimentation equilibrium analysis with compound 2 suggests that heparin-induced FGF1 dimerization is not an absolute requirement for biological activity.

Acidic fibroblast growth factor inhibits junctional communication of Schwann cells in culture.

The effect of acidic fibroblast growth factor (aFGF) was investigated on junctional communication of rat Schwann cells (SC) in culture. As measured by dye transfer, the incidence of coupling between SC was very low during the phase of proliferation and increased slowly and progressively with time under culture conditions that induced the myelinating phenotype. Treatment with aFGF alone or in combination with heparin decreased markedly coupling between SC in both culture stages. The coupling inhibition was rapid, the earliest effects being apparent 5-15 min after addition of growth factor, and was transient with a slower recovery of coupling at 1-3 h. The uncoupling effect of aFGF could be prevented by an inhibitor of protein-tyrosine kinase. Addition of heparin to cultures decreased the most effective aFGF concentration by 100-fold, from 100 ng ml-1 to 1 ng ml-1. The dose-response curves exhibited a characteristic window-shape. The results suggest that FGF might be involved in the regulation of the junctional communication between rat SC via tyrosine kinases.