Inhibition Of Fibroblast Growth Factor Research Articles

Diacetyloxyl derivatization of the fibroblast growth factor inhibitor dobesilate enhances its anti-inflammatory, anti-angiogenic and anti-tumoral activities.

BackgroundDobesilate (2,5-dihydroxyphenyl sulfonate, DHPS) was recently identified as the most potent member of a family of fibroblast growth factor (FGF) inhibitors headed by gentisic acid, one of the main catabolites of aspirin. Although FGFs were first described as inducers of angiogenesis, they were soon recognized as broad spectrum mitogens. Furthermore, in the last decade these proteins have been shown to participate directly in the onset of inflammation, and their potential angiogenic activity often contributes to the inflammatory process in vivo. The aim of this work was to evaluate the anti-inflammatory, anti-angiogenic and anti-tumoral activities of the derivative of DHPS obtained by acetoxylation of its two hydroxyl groups (2,5-diacetoxyphenyl sulfonate; DAPS).MethodsAnti-inflammatory, anti-angiogenic and anti-tumoral activities of DHPS and DAPS were compared using in vivo assays of dermatitis, angiogenesis and tumorigenesis. The effects of both compounds on myeloperoxidase (MPO) and cyclooxygenase (COX) activities, cytokine production and FGF-induced fibroblast proliferation were also determined.ResultsTopical DAPS is more effective than DHPS in preventing inflammatory signs (increased vascular permeability, edema, leukocyte infiltration, MPO activation) caused by contact dermatitis induction in rat ears. DAPS, but not DHPS, effectively inhibits COX-1 and COX-2 activities. DAPS also reduces the increase in serum cytokine concentration induced by lipopolysaccharide in rats. Furthermore, DAPS displays higher in vivo efficacy than DHPS in inhibiting FGF-induced angiogenesis and heterotopic glioma progression, with demonstrated oral efficacy to combat both processes.ConclusionsBy inhibiting both FGF-signaling and COX-mediated prostaglandin synthesis, DAPS efficiently breaks the vicious circle created by the reciprocal induction of FGF and prostaglandins, which probably sustains undesirable inflammation in many circumstances. Our findings define the enhancement of anti-inflammatory, anti-angiogenic and anti-tumoral activities by diacetyloxyl derivatization of the FGF inhibitor, dobesilate.

Efficacy of Dobesilate in Allergic Rhinitis - Case Report

Allergic rhinitis is a common condition that causes a negative effect on patient well-being. Antihistamines and glucocorticoids, the first line treatments usually administered for rhinitis, are normally associated to side effects. In addition, they may show limited efficiency in controlling nasal obstruction, edema and hyperemia occurring secondary to persistent inflammation. Dobesilate, an inhibitor of fibroblast growth factor and vascular endothelial growth factor, shows a markedly anti-inflammatory activity in several inflammation-dependent diseases and inflammation models. Our study shows that nostril spray application of dobesilate for one week is effective in reducing symptoms and signs in patients with seasonal allergic rhinitis.

FGF and Notch signaling hierarchy in sensory neurogenesis (651.18)

The purpose of this study was to determine the regulatory relationship of sensory neurogenesis in the trigeminal placode between the Fibroblast Growth Factor (FGF) and Notch signaling pathways. To do this, FGF signaling was blocked cell autonomously or globally while simultaneously downregulating Notch signaling in 10‐12 somite stage Gallus gallus chick embryos. Cell autonomous FGF inhibition with global Notch downregulation significantly reduced the number of proneural cells contributing the future trigeminal ganglion (p=0.0002). A similar reduction was found with concurrent global inhibition of FGF and Notch (p<0.0001). Remarkably, blocking FGF either cell autonomously or globally with simultaneous Notch downregulation reversed the effects of robust neurogenesis seen with Notch downregulation alone (p<0.0001). Further, Notch downregulation for 4 or 12 hours showed no difference in the level of FGF‐receptor 4 mRNA expression when compared to controls. It did however result in a highly fragmented basal lamina, which was reversed when blocking FGF signaling. From these data, we invalidate the FGF downregulates Notch in sensory neurogenesis model and propose a mechanism for parallel regulation of FGF and Notch leading to basement membrane fragmentation and subsequent delamination of differentiating opV placode cells.Grant Funding Source: Supported by NIH/NICHD ‐ R01 HD046475

Deficiency of Sef Is Associated With Increased Postnatal Cortical Bone Mass by Regulating Runx2 Activity

Sef (similar expression to fgf genes) is a feedback inhibitor of fibroblast growth factor (FGF) signaling and functions in part by binding to FGF receptors and inhibiting their activation. Genetic studies in mice and humans indicate an important role for fibroblast growth factor signaling in bone growth and homeostasis. We, therefore, investigated whether Sef had a function role in skeletal acquisition and remodeling. Sef expression is increased during osteoblast differentiation in vitro, and LacZ staining of Sef+/- mice showed high expression of Sef in the periosteum and chondro-osseous junction of neonatal and adult mice. Mice with a global deletion of Sef showed increased cortical bone thickness, bone volume, and increased periosteal perimeter by micro-computed tomography (micro-CT). Histomorphometric analysis of cortical bone revealed a significant increase in osteoblast number. Interestingly, Sef-/- mice showed very little difference in trabecular bone by micro-CT and histomorphometry compared with wild-type mice. Bone marrow cells from Sef-/- mice grown in osteogenic medium showed increased proliferation and increased osteoblast differentiation compared with wild-type bone marrow cells. Bone marrow cells from Sef-/- mice showed enhanced FGF2-induced activation of the ERK pathway, whereas bone marrow cells from Sef transgenic mice showed decreased FGF2-induced signaling. FGF2-induced acetylation and stability of Runx2 was enhanced in Sef-/- bone marrow cells, whereas overexpression of Sef inhibited Runx2-responsive luciferase reporter activity. Bone marrow from Sef-/- mice showed enhanced hematopoietic lineage-dependent and osteoblast-dependent osteoclastogenesis and increased bone resorptive activity relative to wild-type controls in in vitro assays, whereas overexpression of Sef inhibited osteoclast differentiation. Taken together, these studies indicate that Sef has specific roles in osteoblast and osteoclast lineages and that its absence results in increased osteoblast and osteoclast activity with a net increase in cortical bone mass.

Unanticipated role of apelin: regulation of miRNA generation

Recently, a paper by Kim et al. [1] in Nature Medicine magazine in January, 2013 showed that apelin (also known as APLN) inhibits fibroblast growth factor 2 (FGF2) and FGF receptor 1 (FGFR1) expression to ameliorate pulmonary hypertension by regulating the expression of miR-424 and miR-503. This study revealed the molecular mechanism of apelin in inhibiting the process of pulmonary arterial hypertension (PAH) and discovered the role of apelin in regulating miRNA generation for the first time. miRNA functions in the transcriptional regulation of gene expression to control cellular processes. miRNA is a key regulatory factor of protein expression, but the generation and regulation mechanism of miRNA is still unclear. These novel findings bring us inspiration for further research, especially on the mechanism of miRNA generation. Experiments on revealing endogenous active substance, which regulates the generation of miRNAs or revealing miRNAs that regulate the expression of apelin, may bring more breakthroughs in the future. PAH is characterized by vascular remodeling associated with obliteration of pulmonary arterioles and formation of plexiform lesions composed of hyperproliferative endothelial and vascular smooth muscle cells. Recent studies have suggested that apelin is a novel PAH endothelial function homeostasis-related factor. Alastalo et al. [2] found that apelin expression is decreased in endothelial cells of the pulmonary hypertension. However, the exact mechanism remains poorly understood. FGF2 is highly expressed in PAH and plays an important role in the progress of PAH by promoting proliferation [3] and inhibiting apoptosis [4] in endothelial cells and smooth muscle cells. miRNA is a fundamental factor of numerous cellular events by regulating RNA modification, transcription, and translation. Current studies of miRNA showed its critical function in the development of PAH. Morphological changes of plexiform vasculopathy in the end-stage PAH lung are reflected by alterations at the miRNA level [5]. Kim et al. [1] integrated these isolated observations into a mechanism and identified the miRNA-FGF signaling axis that is apelin-dependent in the maintenance of pulmonary vascular homeostasis. Previous studies found that hypoxia induces endothelial function injury. Accumulating evidence revealed that hypoxia also induces the expression of apelin [6,7],which is reduced in PAH. Actually, apelin expression and secretion, which are strongly induced under hypoxic conditions, are the early response [7]. Mechanisms that maintain sustained expression of apelin may contribute to preventing injuries caused by hypoxia and restoring the function of endothelial cells in PAH. These findings supported the development of novel therapeutic strategies to augment apelin, as well as to inhibit FGF2 signaling. In portal vein hypertension, another vascular disease, apelin/APJ presents a novel therapeutic target. APJ antagonist F13A effectively decreased the formation of portosystemic collateral vessels [8]. In atherosclerosis (AS), increasing evidence tends to prove that apelin is a novel therapeutic target for AS [9]. Although no effective treatment for PAH is available at present, certain medicines are available to mitigate disease progression. Considering its protective effect on vasodilatory and endothelial cells, apelin may be a more efficacious target for PAH therapy. In past decades, apelin was suggested to involve in numerous physiological processes, including vasodilation, systole, salt and water balance, as well as pathophysiological processes such as high blood pressure, cancer, and so on. There must be many other undiscovered functions of apelin. The findings of the intimate relationship between apelin and miRNA provide much fresh thinking for the study of apelin. The study on miR-424 and miR-503 will help to discover additional features of apelin. Park et al. [10] found that the high expression of miR-424 and miR-503 is significantly implicated in chemoresistance and tumor progression in ovarian cancer, which probably regulates cancer stem cell processes. These results indicated that apelin probably plays a vital role in epithelial mesenchymal transition in cancers. A recent study revealed that miR-503 makes women predispose to lupus [11]. The relationship between apelin and lupus has not been explored. More evidence is required to confirm whether apelin controls the effects of miR-424 and miR-503 in the above process. There are some controversial reports of apelin/APJ effects on AS. Chun et al. [12] found that apelin decreases AS formation by blocking AngII actions in ApoE-KO mice. But Hashimoto et al. [13] Acta Biochim Biophys Sin 2013, 45: 896–898 |a The Author 2013. Published by ABBS Editorial Office in association with Oxford University Press on behalf of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences. DOI: 10.1093/abbs/gmt090. Advance Access Publication 28 August 2013

Renal Heparan Sulfate Proteoglycans Modulate Fibroblast Growth Factor 2 Signaling in Experimental Chronic Transplant Dysfunction

Depending on the glycan structure, proteoglycans can act as coreceptors for growth factors. We hypothesized that proteoglycans and their growth factor ligands orchestrate tissue remodeling in chronic transplant dysfunction. We have previously shown perlecan to be selectively up-regulated in the glomeruli and arteries in a rat renal transplantation model. Using the same model, here we present quantitative RT-PCR profiling data on proteoglycans and growth factors from laser-microdissected glomeruli, arterial tunicae mediae, and neointimae at 12 weeks after transplantation. In glomeruli and neointimae of allografts, selective induction of the matrix heparan sulfate proteoglycan perlecan was observed, along with massive accumulation of fibroblast growth factor 2 (FGF2). Profiling the heparan sulfate polysaccharide side chains revealed conversion from a non-FGF2-binding heparan sulfate phenotype in control and isografted kidneys toward a FGF2-binding phenotype in allografts. In vitro experiments with perlecan-positive rat mesangial cells showed that FGF2-induced proliferation is dependent on sulfation and can be inhibited by exogenously added heparan sulfate. These findings indicate that matrix proteoglycans such as perlecan serve as functional docking platforms for FGF2 in chronic transplant dysfunction. We speculate that heparin-like glycomimetics could be a promising intervention to retard development of glomerulosclerosis and neointima formation in chronic transplant dysfunction.

Clinical Efficacy of Intravitreal Injection of Dobesilate for Reversing Choroidal Angiogenesis in Age-Related Macular Degeneration

Wet age-related macular degeneration is associated with chronic ischemia and inflammation that upregulate several inflammatory cytokines and growth factors, particularly vascular endothelial growth factor and fibroblast growth factor which promote the growth of choroidal neovascularization. Only with the introduction of drugs that directly inhibit the actions of vascular endothelial growth factor have ophthalmologists been able to offer patients with wet age-related macular degeneration reasonable hope for improvement of vision. However, intravitreal administration of anti-vascular endothelial growth factor drugs could be associated with unexpected ocular and systemic side effects. We present consecutive case series of 64 eyes of 64 patients with wet age-related macular degeneration treated with a single intravitreal injection of Dobesilate, a synthetic fibroblast growth factor inhibitor. The end points were the improvement from baseline visual acuity and normalization of retinal histology at 1 month. Intravitreal Dobesilate injection results in a significant improvement in functional and anatomic outcomes from the first month after injection. There were no cases of treatment-associated complications.

Inhibition of Tumor Angiogenesis and Growth by a Small-Molecule Multi-FGF Receptor Blocker with Allosteric Properties

Receptor tyrosine kinases (RTK) are targets for anticancer drug development. To date, only RTK inhibitors that block orthosteric binding of ligands and substrates have been developed. Here, we report the pharmacologic characterization of the chemical SSR128129E (SSR), which inhibits fibroblast growth factor receptor (FGFR) signaling by binding to the extracellular FGFR domain without affecting orthosteric FGF binding. SSR exhibits allosteric properties, including probe dependence, signaling bias, and ceiling effects. Inhibition by SSR is highly conserved throughout the animal kingdom. Oral delivery of SSR inhibits arthritis and tumors that are relatively refractory to anti-vascular endothelial growth factor receptor-2 antibodies. Thus, orally-active extracellularly acting small-molecule modulators of RTKs with allosteric properties can be developed and may offer opportunities to improve anticancer treatment.

The role of FGF signaling in VEGF-pathway targeted therapy resistance: Data from patients and model systems.

386 Background: Angiogenesis plays a role in tumor growth and is partly mediated by factors in both the fibroblast growth factor (FGF) and vascular endothelial growth factor (VEGF) pathways. Brivanib inhibits both VEGF receptor 2 and FGF receptors (FGFR)-1/2. Methods: Nephrectomy material from 40 patients with metastatic renal cell carcinoma (RCC) receiving sorafenib ± interferon was assessed by immunohistochemical (IHC) staining. The Ariol imaging platform was used to stratify the specimens based on intensity of staining for FGF biomarkers: FGFR-1 and fibroblast growth factor receptor substrate 2 (pFRS2). The relationship between fibroblast growth factor pathway marker levels and progression-free survival (PFS) was analyzed using Kaplan-Meier and Cox proportional hazards regression methods. To assess the efficacy of dual targeting of VEGF and FGF receptor signaling by brivanib, we treated a xenograft RCC mouse model with sunitinib, brivanib, or sunitinib followed by brivanib. Results: Our analysis indicated that more intense FGFR-1 staining was associated with shorter PFS (p = 0.0452), and that pFRS2 staining were not significantly associated with PFS (p = 0.2610). FGF pathway activation was associated with decreased PFS in patients with metastatic RCC treated with sorafenib. Xenograft mice were treated with 20 mg/kg sunitinib and after an initial stabilization phase, resistance developed by day 20. A switch to 30 mg/kg brivanib prolonged the stabilization phase after progression on sunitinib (p = 0.0033). Conclusions: The PFS of patients treated with sorafenib is associated with FGF pathway activation. In a xenograft RCC mouse model, brivanib overcame the tumor escape after initial treatment with sunitinib. Switching from sunitinib to brivanib at the time of tumor escape prolonged the stabilization phase and overcame a sunitinib-induced resistance phenotype. The results suggest that FGF pathway activation mediates both innate and acquired tumor resistance to VEGF receptor inhibition. The efficacy of dual inhibition of FGF and VEGF in the subset of patients with increased FGF activation prior to treatment requires further study.

Dobesilate for dry age-related macular degeneration

We have evaluated the effects of intravitreal dobesilate, a synthetic fibroblast growth factor inhibitor, in patients with dry age-related macular degeneration, an inflammatory-related retinal disease without available treatment up to date. 36 eyes from 36 patients with dry age-related macular degeneration were treated with a single intravitreal dobesilate injection. The end points were the improvement from baseline visual acuity and normalization of retinal histology at one month. Intravitreal dobesilate injection resulted in a significant improvement in functional and anatomical outcomes at one month after injection. Our results suggest that intravitreal dobesilate may increase the chance of visual acuity gain in dry age-related macular degeneration, even in cases with initial low vision. This study supports the findings of previously published case reports, regarding the short-term improvement in visual acuity by intravitreal dobesilate injection in different degenerative retinal diseases.

Pharmacological inhibition of fibroblast growth factor (FGF) receptor signaling ameliorates FGF23-mediated hypophosphatemic rickets

Fibroblast growth factor 23 (FGF23) is a circulating factor secreted by osteocytes that is essential for phosphate homeostasis. In kidney proximal tubular cells FGF23 inhibits phosphate reabsorption and leads to decreased synthesis and enhanced catabolism of 1,25-dihydroxyvitamin D3 (1,25[OH]2 D3 ). Excess levels of FGF23 cause renal phosphate wasting and suppression of circulating 1,25(OH)2 D3 levels and are associated with several hereditary hypophosphatemic disorders with skeletal abnormalities, including X-linked hypophosphatemic rickets (XLH) and autosomal recessive hypophosphatemic rickets (ARHR). Currently, therapeutic approaches to these diseases are limited to treatment with activated vitamin D analogues and phosphate supplementation, often merely resulting in partial correction of the skeletal aberrations. In this study, we evaluate the use of FGFR inhibitors for the treatment of FGF23-mediated hypophosphatemic disorders using NVP-BGJ398, a novel selective, pan-specific FGFR inhibitor currently in Phase I clinical trials for cancer therapy. In two different hypophosphatemic mouse models, Hyp and Dmp1-null mice, resembling the human diseases XLH and ARHR, we find that pharmacological inhibition of FGFRs efficiently abrogates aberrant FGF23 signaling and normalizes the hypophosphatemic and hypocalcemic conditions of these mice. Correspondingly, long-term FGFR inhibition in Hyp mice leads to enhanced bone growth, increased mineralization, and reorganization of the disturbed growth plate structure. We therefore propose NVP-BGJ398 treatment as a novel approach for the therapy of FGF23-mediated hypophosphatemic diseases.

Eosinophil cationic protein enhances cardiomyocyte differentiation of P19CL6 embryonal carcinoma cells by stimulating the FGF receptor signaling pathway

We investigated the functional role of eosinophil cationic protein (ECP) in regulating cardiomyogenesis using mouse P19CL6 embryonic carcinoma cells. ECP was confirmed to accelerate the cardiomyocyte differentiation of P19CL6 cells by enhancing the rate and area size of beating of cardiomyocyte and by facilitating the expression of cardiomyocyte-specific genes, such as GATA4 and α-MHC. Since cardiomyocyte differentiation in vivo is considered to follow mesoderm induction, the induction of Brachyury, a marker of mesoderm, was assessed. Brachyury expression was found to be enhanced after the addition of ECP. This enhancement was due to the stimulation of extracellular signal-regulated kinase (ERK)1/2 phosphorylation by ECP. In this context, treatment with SU5402, an inhibitor of fibroblast growth factor (FGF) receptor 1, suppressed Brachyury expression, phosphorylation of ERK1/2, and cardiomyocyte differentiation induced by ECP. We concluded that ECP might induce mesoderm differentiation through FGF signaling pathway and enhance subsequent cardiomyocyte differentiation in concert with dimethyl sulfoxide in P19CL6 cells. ECP may be a novel factor for cardiomyocyte differentiation, which should be very useful to prepare adequate numbers of cardiomyocytes for therapeutic cell transplantation.

Life or Death Decisions in the Corpus Luteum

The corpus luteum (CL) is an ephemeral endocrine organ. During its lifespan, it undergoes a period of extremely rapid growth that involves hypertrophy, proliferation and differentiation of the steroidogenic cells, as well as extensive angiogenesis. The growth phase is followed by a period in which remodelling of the tissue ceases, but it engages in unparalleled production of steroids, resulting in extraordinarily high metabolic activity within the tissue. It is during this stage that a critical juncture occurs. In the non-fertile cycle, uterine release of prostaglandin (PG)F(2α) initiates a cascade of events that result in rapid loss of steroidogenesis and destruction of the luteal tissue. Alternatively, if a viable embryo is present, signals are produced that result in rescue of the CL. This review article summarizes the major concepts related to the fate of the CL, with particular focus on recent insights into the mechanisms associated with the ability of PGF(2α) to bring about complete luteolysis. It has become clear that the achievement of luteolysis depends on repeated exposure to PGF(2α) and involves coordinated actions of heterogeneous cell types within the CL. Together, these components of the process bring about not only the loss in progesterone production, but also the rapid demise of the structure itself.

Lack of Effect of Brivanib on the Pharmacokinetics of Midazolam, a CYP3A4 Substrate, Administered Intravenously and Orally in Healthy Participants

Brivanib alaninate is the orally available prodrug of brivanib, a dual inhibitor of fibroblast growth factor and vascular endothelial growth factor signaling pathways that is under therapeutic investigation for various malignancies. Brivanib alaninate inhibits CYP3A4 in vitro, and thus there is potential for drug-drug interaction with CYP3A4 substrates, such as midazolam. The present study evaluated pharmacokinetic parameters and safety/tolerability upon coadministration of brivanib alaninate and midazolam. Healthy participants received intravenous (IV) or oral midazolam with and without oral brivanib alaninate. Blood samples for pharmacokinetic analysis were collected up to 12 hours after midazolam and up to 48 hours after brivanib alaninate. Twenty-four participants were administered study drugs; 21 completed the trial. No clinically relevant effect of brivanib alaninate on the overall exposure to midazolam following IV or oral administration was observed. Orally administered brivanib alaninate was generally well tolerated in the presence of IV or oral midazolam. The lack of a pharmacokinetic interaction between brivanib and midazolam indicates that brivanib alaninate does not influence either intestinal or hepatic CYP3A4 and confirms that brivanib alaninate may be safely coadministered with midazolam and other CYP3A4 substrates.

Lenalidomide for second-line treatment of advanced hepatocellular cancer (HCC): A Brown University Oncology Group phase II study.

4098 Background: Lenalidomide inhibits fibroblast growth factor (FGF), vascular endothelial growth factor (VEGF) and multiple tumor growth pathways. There is no standard of care for patients who progress after sorafenib. Therefore, we performed a phase II study to determine the activity of lenalidomide in second-line HCC therapy. Methods: Patients with advanced HCC who progressed on or were intolerant to sorafenib were eligible. Prior chemoembolization, RFA, or surgery were allowed. Eligibility criteria also included bilirubin <4 mg/dL, AST and ALT <5 times upper limit of normal, ECOG performance status 0-2, platelet count >60,000/mm3, absolute neutrophil count >1000/mm3, and creatinine <2mg/dL. Patients were treated with lenalidomide 25mg orally days 1-21 of a 28 day cycle until disease progression or unacceptable toxicities. The planned original sample size was 25 patients but when early activity was demonstrated the study was expanded to 40 patients. Results: The study has completed accrual of 40 patients. The median age was 60.5 years (17-88 years). Nineteen patients were Child-Pugh A, 16 patients were B, and 5 patients were C. Twenty four patients had extrahepatic disease. Preliminary data is available on the first 37 patients. One patient had grade 4 neutropenia. Grade 3 toxicities included ANC (n=2), fatigue (n=4), rash (n=2), arthritis (n=1), diarrhea (n=1), dehydration (n=2). One patient developed variceal bleeding which precipitated encephalopathy and death. Of the 32 patients with elevated baseline AFP, nine (28%) had a >50% reduction including one patient with a reduction in AFP from 56,900ng/ml to 5 ng/ml. Six of the first 37 patients (16%) had a radiographic partial response. Two patients achieved a complete response and have not progressed at 36 and 32 months. Conclusions: Lenalidomide can be administered to patients with advanced HCC and significant hepatic dysfunction. Promising, and in a small percentage of patients, dramatic and durable activity has been demonstrated. Investigations are underway to explore the mechanism of action of lenalidomide in HCC.

A combinatorial in silico and cellular approach to identify a new class of compounds that target VEGFR2 receptor tyrosine kinase activity and angiogenesis

Vascular endothelial growth factor receptor 2 (VEGFR2) is an attractive therapeutic target for the treatment of diseases such as cancer. Small-molecule VEGFR2 inhibitors of a variety of chemical classes are currently under development or in clinical use. In this study, we describe the de novo design of a new generation pyrazole-based molecule (JK-P3) that targets VEGFR2 kinase activity and angiogenesis. JK-P compound series were designed using de novo structure-based identification methods. Compounds were tested in an in vitro VEGFR2 kinase assay. Using primary endothelial cells, JK-P compounds were assessed for their ability to inhibit VEGF-A-stimulated VEGFR2 activation and intracellular signalling. We tested these compounds in cell migration, proliferation and angiogenesis assays. JK-P3 and JK-P5 were predicted to bind the VEGFR2 kinase domain with high affinity, and both compounds showed pronounced inhibition of endogenous VEGFR2 kinase activity in primary human endothelial cells. Only JK-P3 inhibited VEGF-A-stimulated VEGFR2 activation and intracellular signalling. Interestingly, JK-P3 inhibited endothelial monolayer wound closure and angiogenesis but not endothelial cell proliferation. Both compounds inhibited fibroblast growth factor receptor kinase activity in vitro, but not basic fibroblast growth factor-mediated signalling in endothelial cells. This is the first report that describes an anti-angiogenic inhibitor based on such a pyrazole core. Using a de novo structure-based identification approach is an attractive method to aid such drug discovery. These results thus provide an important basis for the development of multi-tyrosine kinase inhibitors for clinical use in the near future.

Phase II, Open-Label Study of Brivanib as Second-Line Therapy in Patients with Advanced Hepatocellular Carcinoma

Brivanib, a selective dual inhibitor of fibroblast growth factor and VEGF signaling, has recently been shown to have activity as first-line treatment for patients with advanced hepatocellular carcinoma (HCC). This phase II open-label study assessed brivanib as second-line therapy in patients with advanced HCC who had failed prior antiangiogenic treatment. Brivanib was administered orally at a dose of 800 mg once daily. The primary objectives were tumor response rate, time to response, duration of response, progression-free survival, overall survival (OS), disease control rate, time to progression (TTP), and safety and tolerability. Forty-six patients were treated. Best responses to treatment with brivanib (N = 46 patients) using modified World Health Organization criteria were partial responses for two patients (4.3%), stable disease for 19 patients (41.3%), and progressive disease for 19 patients (41.3%). The tumor response rate was 4.3%; the disease control rate was 45.7%. Median OS was 9.79 months. Median TTP as assessed by study investigators following second-line treatment with brivanib was 2.7 months. The most common adverse events were fatigue, decreased appetite, nausea, diarrhea, and hypertension. Brivanib had a manageable safety profile and is one of the first agents to show promising antitumor activity in advanced HCC patients treated with prior sorafenib.

Organ-specific Sulfation Patterns of Heparan Sulfate Generated by Extracellular Sulfatases Sulf1 and Sulf2 in Mice

Heparan sulfate endosulfatases Sulf1 and Sulf2 hydrolyze 6-O-sulfate in heparan sulfate, thereby regulating cellular signaling. Previous studies have revealed that Sulfs act predominantly on UA2S-GlcNS6S disaccharides and weakly on UA-GlcNS6S disaccharides. However, the specificity of Sulfs and their role in sulfation patterning of heparan sulfate in vivo remained unknown. Here, we performed disaccharide analysis of heparan sulfate in Sulf1 and Sulf2 knock-out mice. Significant increases in ΔUA2S-GlcNS6S were observed in the brain, small intestine, lung, spleen, testis, and skeletal muscle of adult Sulf1(-/-) mice and in the brain, liver, kidney, spleen, and testis of adult Sulf2(-/-) mice. In addition, increases in ΔUA-GlcNS6S were seen in the Sulf1(-/-) lung and small intestine. In contrast, the disaccharide compositions of chondroitin sulfate were not primarily altered, indicating specificity of Sulfs for heparan sulfate. For Sulf1, but not for Sulf2, mRNA expression levels in eight organs of wild-type mice were highly correlated with increases in ΔUA2S-GlcNS6S in the corresponding organs of knock-out mice. Moreover, overall changes in heparan sulfate compositions were greater in Sulf1(-/-) mice than in Sulf2(-/-) mice despite lower levels of Sulf1 mRNA expression, suggesting predominant roles of Sulf1 in heparan sulfate desulfation and distinct regulation of Sulf activities in vivo. Sulf1 and Sulf2 mRNAs were differentially expressed in restricted types of cells in organs, and consequently, the sulfation patterns of heparan sulfate were locally and distinctly altered in Sulf1 and Sulf2 knock-out mice. These findings indicate that Sulf1 and Sulf2 differentially contribute to the generation of organ-specific sulfation patterns of heparan sulfate.

Topical Treatment of Skin Squamous Cell Carcinoma with Potassium Dobesilate Cream

Skin squamous cell carcinoma, the second most common skin cancer arises from the malignant proliferation of keratinocytes in the epidermis. Although it is locally invasive, surgical excision or topical therapy is usually curative. However, surgical management of skin squamous cell carcinoma located in certain regions of the body may require reconstructive procedures. This can result in significant scarring and increased morbidity and dysfunction. Topical therapy may be preferable to surgery depending on anatomic localizations, and in instances where patients reject it or are poor surgical candidates. Fibroblast growth factors are variously implicated in skin tumorigenesis where they may be involved in the enhancement of tumor cell proliferation and viability, induction of angiogenesis and stimulation of tumor invasiveness. We investigated the efficacy and safety of the fibroblast growth factor inhibitor, dobesilate, administered as a 5% potassium cream, for the treatment of skin squamous cell carcinoma. Two months application of dobesilate cleared squamous cell carcinoma probably due to inhibition of cell proliferation and angiogenesis, and induction of tumor cell apoptosis. No local side effects were observed in relation with treatment. This report highlights the need for efficient and safe topical therapies in the management of skin neoplasms and supports the use of potassium dobesilate in non-melanoma skin cancers treatment.

Antibody-Mediated Inhibition of Fibroblast Growth Factor 19 Results in Increased Bile Acids Synthesis and Ileal Malabsorption of Bile Acids in Cynomolgus Monkeys

Fibroblast growth factor 19 (FGF19) represses cholesterol 7α-hydroxylase (Cyp7α1) and inhibits bile acid synthesis in vitro and in vivo. Previous studies have shown that anti-FGF19 antibody treatment reduces growth of colon tumor xenografts and prevents hepatocellular carcinomas in FGF19 transgenic mice and thus may be a useful cancer target. In a repeat dose safety study in cynomolgus monkeys, anti-FGF19 treatment (3-100 mg/kg) demonstrated dose-related liver toxicity accompanied by severe diarrhea and low food consumption. The mechanism of anti-FGF19 toxicity was investigated using in vitro and in vivo approaches. Our results show that anti-FGF19 antibody had no direct cytotoxic effect on monkey hepatocytes. Anti-FGF19 increased Cyp7α1, as expected, but also increased bile acid efflux transporter gene (bile salt export pump, multidrug resistant protein 2 [MRP2], and MRP3) expression and reduced sodium taurocholate cotransporting polypeptide and organic anion transporter 2 expression in liver tissues from treated monkeys and in primary hepatocytes. In addition, anti-FGF19 treatment increased solute transporter gene (ileal bile acid-binding protein, organic solute transporter α [OST-α], and OST-β) expression in ileal tissues from treated monkeys but not in Caco-2 cells. However, deoxycholic acid (a secondary bile acid) increased expression of FGF19 and these solute transporter genes in Caco-2 cells. Gas chromatography-mass spectrometry analysis of monkey feces showed an increase in total bile acids and cholic acid derivatives. These findings suggest that high doses of anti-FGF19 increase Cyp7α1 expression and bile acid synthesis and alter the expression of bile transporters in the liver resulting in enhanced bile acid efflux and reduced uptake. Increased bile acids alter expression of solute transporters in the ileum causing diarrhea and the enhanced enterohepatic recirculation of bile acids leading to liver toxicity.