The antifungal drug itraconazole inhibits vascular endothelial growth factor receptor 2 (VEGFR2) glycosylation, trafficking, and signaling in endothelial cells

Novel Tetrazole-Containing Analogues of Itraconazole as Potent Antiangiogenic Agents with Reduced Cytochrome P450 3A4 Inhibition

Itraconazole has been found to possess potent antiangiogenic activity, exhibiting promising antitumor activity in several human clinical studies. The wider use of itraconazole in the treatment of cancer, however, has been limited by its potent inhibition of the drug metabolizing enzyme cytochrome P450 3A4 (CYP3A4). In an effort to eliminate the CYP3A4 inhibition while retaining its antiangiogenic activity, we designed and synthesized a series of derivatives in which the 1,2,4-triazole ring is replaced with various azoles and nonazoles. Among these analogues, 15n with tetrazole in place of 1,2,4-triazole exhibited optimal inhibition of human umbilical vein endothelial cell proliferation with an IC₅₀ of 73 nM without a significant effect on CYP3A4 (EC₅₀ > 20 μM). Similar to itraconazole, 15n induced Niemann-Pick C phenotype (NPC phenotype) and blocked AMPK/mechanistic target of rapamycin signaling. These results suggest that 15n is a promising angiogenesis inhibitor that can be used in combination with most other known anticancer drugs.

Inhibition of VEGF-Flk-1 binding induced profound biochemical alteration in the hippocampus of a rat model of BBB breakdown by spider venom. A preliminary assessment using FT-IR spectroscopy

Phoneutria nigriventer spider venom (PNV) contains ion channels-acting neuropeptides that in rat induces transitory blood-brain barrier breakdown (BBBb) in hippocampus in parallel with VEGF upregulation. We investigated whether VEGF has a neuroprotective role by inhibiting its binding to receptor Flk-1 by itraconazole (ITZ). FT-IR spectroscopy examined the biochemical status of hippocampus and evaluated BBBb in rats administered PNV or ITZ/PNV at periods with greatest toxicity (1-2h), recovery (5h) and visual absence of symptoms (24h), and compared to saline and ITZ controls. The antifungal treatment before venom intoxication aggravated the venom effects and increased BBB damage. FT-IR spectra of venom, hippocampi of controls, PNV and ITZ-PNV showed a 1400 cm^-1 band linked to symmetric stretch of carboxylate and 1467 cm^-1 band (CH₂ bending: mainly lipids) that were considered biomarker and reference bands, respectively. Inhibition of VEGF/Flk-1 binding produced marked changes in lipid/protein stability at 1-2h. The largest differences were observed in spectra regions assigned to lipids, both symmetric (2852 cm^-1) and asymmetric (2924 and 2968 cm^-1). Quantitative analyses showed greatest increases in the 1400 cm^-1/1467 cm^-1 ratio also at 1h. Such changes at period of rats' severe intoxication referred to wavenumber region from 3106 cm^-1 to 687 cm^-1 assigning for C-H and N-H stretching of protein, Amide I, C=N cytosine, N-H adenine, Amide II, CH₂ bending: mainly lipids, C-O stretch: glycogen, polysaccharides, glycolipids, z-type DNA, C-C, C-O and CH out-of-plane bending vibrations. We conclude that VEGF has a neuroprotective role and can be a therapeutic target in PNV envenomation. FT-IR spectroscopy showed to be instrumental for monitoring biochemical changes in this model of P. nigriventer venom-induced BBB disruption.

Itraconazole inhibits the proliferation of gastric cancer cells in vitro and improves patient survival

Itraconazole is a Food and Drug Administration-approved antifungal drug belonging to the azole family. Recent studies reported that itraconazole has potential anticancer activity. Whether combining itraconazole with other anticancer compounds such as 5-fluorouracil (5-FU), a potent drug used in the treatment of gastric cancer, is unknown and warrants further study. In the present study, SGC-7901 gastric cancer cells were chosen to assess the anticancer effects of itraconazole in combination with 5-FU. Cell proliferation was assessed by a Cell Counting Kit-8 assay, and apoptosis was assessed by Annexin V/propidium iodide (PI) staining and flow cytometry. Cell cycle distribution was determined by PI staining and flow cytometer. Single-cell gel electrophoresis was used to estimate DNA damage. Medical records of patients with gastric cancer were retrospectively reviewed, and the patients treated with itraconazole were selected for the present study. Itraconazole treatment inhibited the proliferation and altered cell cycle in SGC-7901 cells while promoting early apoptosis and DNA damage. These effects were promoted in cells treated with both itraconazole and 5-FU. Combination itraconazole and 5-FU treatment showed a synergetic anticancer effect in SGC-7901 cells. in vivo, itraconazole was able to improve the outcome of 5-FU-based chemotherapy. Itraconazole alone and in combination with 5-FU was able to inhibit the growth of gastric cancer in vitro, and it was able to prolong the survival of patients with gastric cancer.

Structure-activity relationship study of itraconazole, a broad-range inhibitor of picornavirus replication that targets oxysterol-binding protein (OSBP)

Itraconazole (ITZ) is a well-known, FDA-approved antifungal drug that is also in clinical trials for its anticancer activity. ITZ exerts its anticancer activity through several disparate targets and pathways. ITZ inhibits angiogenesis by hampering the functioning of the vascular endothelial growth receptor 2 (VEGFR2) and by indirectly inhibiting mTOR signaling. Furthermore, ITZ directly inhibits the growth of several types of tumor cells by antagonizing Hedgehog signaling. Recently, we reported that ITZ also has broad-spectrum antiviral activity against enteroviruses, cardioviruses and hepatitis C virus, independent of established ITZ-activities but instead via a novel target, oxysterol-binding protein (OSBP), a cellular lipid shuttling protein. In this study, we analyzed which structural features of ITZ are important for the OSBP-mediated antiviral activity. The backbone structure, consisting of five rings, and the sec-butyl chain are important for antiviral activity, whereas the triazole moiety, which is critical for antifungal activity, is not. The features required for OSBP-mediated antiviral activity of ITZ overlap mostly with published features required for inhibition of VEGFR2 trafficking, but not Hh signaling. Furthermore, we use in silico studies to explore how ITZ could bind to OSBP. Our data show that several pharmacological activities of ITZ can be uncoupled, which is a critical step in the development of ITZ-based antiviral compounds with greater specificity and reduced off-target effects.

Drug repurposing in malignant pleural mesothelioma: a breath of fresh air?

Drug repurposing is the use of known drugs for new indications. Malignant pleural mesothelioma (MPM) is a rare cancer with a poor prognosis. So far, few treatments have been approved in this disease. However, its incidence is expected to increase significantly, particularly in developing countries. Consequently, drug repurposing appears as an attractive strategy for drug development in MPM, since the known pharmacology and safety profile based on previous approvals of repurposed drugs allows for faster time-to-market for patients and lower treatment cost. This is critical in low- and middle-income countries where access to expensive drugs is limited. This review assesses the published preclinical and clinical data about drug repurposing in MPM.In this review, we identified 11 therapeutic classes that could be repositioned in mesothelioma. Most of these treatments have been evaluated in vitro, half have been evaluated in vivo in animal models of MPM and only three (i.e. valproate, thalidomide and zoledronic acid) have been investigated in clinical trials, with limited benefits so far. Efforts could be coordinated to pursue further investigations and test promising drugs identified in preclinical experiments in appropriately designed clinical trials.

Multi-physics interactions drive VEGFR2 relocation on endothelial cells

Vascular Endothelial Growth Factor Receptor-2 (VEGFR2) is a pro-angiogenic receptor, expressed on endothelial cells (ECs). Although biochemical pathways that follow the VEGFR2 activation are well established, knowledge about the dynamics of receptors on the plasma membrane remains limited. Ligand stimulation induces the polarization of ECs and the relocation of VEGFR2, either in cell protrusions or in the basal aspect in cells plated on ligand-enriched extracellular matrix (ECM). We develop a mathematical model in order to simulate the relocation of VEGFR2 on the cell membrane during the mechanical adhesion of cells onto a ligand-enriched substrate. Co-designing the in vitro experiments with the simulations allows identifying three phases of the receptor dynamics, which are controlled respectively by the high chemical reaction rate, by the mechanical deformation rate, and by the diffusion of free receptors on the membrane. The identification of the laws that regulate receptor polarization opens new perspectives toward developing innovative anti-angiogenic strategies through the modulation of EC activation.

Effect of itraconazole on the cornea in a murine suture model and penetrating keratoplasty model

AIM

To investigate the anti-(lymph)angiogenic and/or anti-inflammatory effect of itraconazole in a corneal suture model and penetrating keratoplasty (PK) model.

METHODS

Graft survival, corneal neovascularization, and corneal lymphangiogenesis were compared among itraconazole, amphotericin B, dexamethasone, phosphate buffered saline (PBS) and surgery-only groups following subconjunctival injection in mice that underwent PK and corneal suture. Immunohistochemical staining and analysis were performed in each group. Real-time polymerase chain reaction (RT-PCR) was performed to quantify the expression of inflammatory cytokines (TNF-alpha, IL-6) and vascular endothelial growth factor (VEGF)-A, VEGF-C, VEGFR-2, and VEGFR-3.

RESULTS

In the suture model, the itraconazole group showed less angiogenesis, less lymphangiogenesis, and less inflammatory infiltration than the PBS group (all P<0.05). The itraconazole group showed reduced expression of VEGF-A, VEGFR-2, TNF-alpha, IL-6 than the PBS group (all P<0.05). In PK model, the two-month graft survival rate was 28.57% in itraconazole group, 62.50% in dexamethasone group, 12.50% in PBS group, 0 in amphotericin B group and 0 in surgery-only group. Graft survival in the itraconazole group was higher than that in the amphotericin, PBS and surgery-only group (P=0.057, 0.096, 0.012, respectively). The itraconazole group showed less total angiogenesis and lymphangiogenesis than PBS group (all P<0.05).

CONCLUSION

Itraconazole decrease neovascularization, lymphangiogenesis, and inflammation in both a corneal suture model and PK model. Itraconazole has anti-(lymph)-angiogenic and anti-inflammatory effects in addition to its intrinsic antifungal effect and is therefore an alternative treatment option in cases where steroids cannot be used.

Contribution of vascular endothelial growth factor receptor-2 sialylation to the process of angiogenesis

Vascular endothelial growth factor receptor-2 (VEGFR2) is the main pro-angiogenic receptor expressed by endothelial cells (ECs). Using surface plasmon resonance, immunoprecipitation, enzymatic digestion, immunofluorescence and cross-linking experiments with specific sugar-binding lectins, we demonstrated that VEGFR2 bears both α,1-fucose and α(2,6)-linked sialic acid (NeuAc). However, only the latter is required for VEGF binding to VEGFR2 and consequent VEGF-dependent VEGFR2 activation and motogenic response in ECs. Notably, downregulation of β-galactoside α(2,6)-sialyltransferase expression by short hairpin RNA transduction inhibits VEGFR2 α(2,6) sialylation that is paralleled by an increase of β-galactoside α(2,3)-sialyltransferase expression. This results in an ex-novo α(2,3)-NeuAc sialylation of the receptor that functionally replaces the lacking α(2,6)-NeuAc, thus allowing VEGF/VEGFR2 interaction. In keeping with the role of VEGFR2 sialylation in angiogenesis, the α(2,6)-NeuAc-binding lectin Sambucus nigra (SNA) prevents VEGF-dependent VEGFR2 autophosphorylation and EC motility, proliferation and motogenesis. In addition, SNA exerts a VEGF-antagonist activity in tridimensional angiogenesis models in vitro and in the chick-embryo chorioallantoic membrane neovascularization assay and mouse matrigel plug assay in vivo. In conclusion, VEGFR2-associated NeuAc plays an important role in modulating VEGF/VEGFR2 interaction, EC pro-angiogenic activation and neovessel formation. VEGFR2 sialylation may represent a target for the treatment of angiogenesis-dependent diseases.

Repurposing itraconazole as an anticancer agent

Itraconazole, a common anti-fungal agent, has demonstrated potential anticancer activity, including reversing chemoresistance mediated by P-glycoprotein, modulating the signal transduction pathways of Hedgehog, mechanistic target of rapamycin and Wnt/β-catenin in cancer cells, inhibiting angiogenesis and lymphangiogenesis, and possibly interfering with cancer-stromal cell interactions. Clinical trials have suggested the clinical benefits of itraconazole monotherapy for prostate cancer and basal cell carcinoma, as well as the survival advantage of combination chemotherapy for relapsed non-small cell lung, ovarian, triple negative breast, pancreatic and biliary tract cancer. As drug repurposing is cost-effective and timesaving, a review was conducted of preclinical and clinical data focusing on the anticancer activity of itraconazole, and discusses the future directions for repurposing itraconazole as an anticancer agent.

The anti-cancer effects of itraconazole in epithelial ovarian cancer

We assessed the anti-proliferative activity of itraconazole using an EOC cell line (SKOV3ip1) and endothelial cell lines (HUVEC & SVEC4-10). We also examined angiogenesis (VEGFR2, p-ERK, p-PLCr1/2), hedgehog (Gli1, Ptch1, SMO), and mTOR (pS6K1) signaling pathways to determine the mechanism of action of itraconazole. Furthermore, we evaluated the synergistic effects of itraconazole and paclitaxel using orthotopic mouse models with established EOC cells (SKOV3ip1 or HeyA8) as well as patient-derived xenografts (PDXs). Itraconazole treatment inhibited proliferation of endothelial cells in a dose-dependent manner, but had no effect on EOC cells. The endothelial cell antiproliferative effect was associated with inhibition of hedgehog, and mTOR pathways and angiogenesis. In xenograft models of EOC using SKOV3ip1 or HeyA8, mice treated with the combination of itraconazole and paclitaxel had significantly decreased tumor weight than the control, paclitaxel-alone, or itraconazole-alone groups. Tissue derived from these tumors had significantly lower microvessel density than tissue from the other groups as well as hedgehog and mTOR pathway inhibition. We confirmed those effects in two EOC PDX models. These results suggest that itraconazole selectively inhibits endothelial cells rather than cancer cells by targeting multiple pathways including hedgehog, and mTOR pathways and angiogenesis.

Drug repurposing in cancer

Cancer is a major health issue worldwide, and the global burden of cancer is expected to increase in the coming years. Whereas the limited success with current therapies has driven huge investments into drug development, the average number of FDA approvals per year has declined since the 1990s. This unmet need for more effective anti-cancer drugs has sparked a growing interest for drug repurposing, i.e. using drugs already approved for other indications to treat cancer. As such, data both from pre-clinical experiments, clinical trials and observational studies have demonstrated anti-tumor efficacy for compounds within a wide range of drug classes other than cancer. Whereas some of them induce cancer cell death or suppress various aspects of cancer cell behavior in established tumors, others may prevent cancer development. Here, we provide an overview of promising candidates for drug repurposing in cancer, as well as studies describing the biological mechanisms underlying their anti-neoplastic effects.

Repurposing itraconazole for the treatment of cancer

The repurposing of drugs is becoming increasingly attractive as it avoids the lengthy process and cost implications associated with bringing a novel drug to market. Itraconazole is a broad-spectrum anti-fungal agent. An emerging body of in vivo, in vitro and clinical evidence have confirmed that it also possesses antineoplastic activities and has a synergistic action when combined with other chemotherapeutic agents. It acts via several mechanisms to prevent tumour growth, including inhibition of the Hedgehog pathway, prevention of angiogenesis, decreased endothelial cell proliferation, cell cycle arrest and induction of auto-phagocytosis. These allow itraconazole, either alone or in combination with other cytotoxic agents, to increase drug efficacy and overcome drug resistance. This study reviews the reported literature on the use of itraconazole in a variety of malignancies and highlights the recent insights into the critical pathways acted upon to prevent tumour growth.

Intravitreal itraconazole inhibits laser-induced choroidal neovascularization in rats

Choroidal neovascularization (CNV) is a major cause of severe visual loss in patients with age-related macular degeneration (AMD). Recently, itraconazole has shown potent and dose-dependent inhibition of tumor-associated angiogenesis. We evaluated the anti-angiogenic effect of itraconazole in a rat model of laser-induced CNV. After laser photocoagulation in each eye to cause CNV, right eyes were administered intravitreal injections of itraconazole; left eyes received balanced salt solution (BSS) as controls. On day 14 after laser induction, fluorescein angiography (FA) was used to assess abnormal vascular leakage. Flattened retinal pigment epithelium (RPE)-choroid tissue complex was stained with Alexa Fluor 594-conjugated isolectin B4 to measure the CNV area and volume. Vascular endothelial growth factor receptor 2 (VEGFR2) mRNA and protein expression was determined 1, 4, 7, and 14 days after intravitreal injection by quantitative RT-PCR or Western blot. VEGF levels were analyzed by enzyme-linked immunosorbent assay (ELISA). Intravitreal itraconazole significantly reduced leakage from CNV as assessed by FA and CNV area and volume on flat mounts compared with intravitreal BSS (p = 0.002 for CNV leakage, p<0.001 for CNV area and volume). Quantitative RT-PCR showed significantly lower expression of VEGFR2 mRNA in the RPE-choroid complexes of itraconazole-injected eyes than those of BSS-injected eyes on days 7 and 14 (p = 0.003 and p = 0.006). Western blots indicated that VEGFR2 was downregulated after itraconazole treatment. ELISA showed a significant difference in VEGF level between itraconazole-injected and BSS-injected eyes on days 7 and 14 (p = 0.04 and p = 0.001). Our study demonstrated that intravitreal itraconazole significantly inhibited the development of laser-induced CNV in rats. Itraconazole had anti-angiogenic activity along with the reduction of VEGFR2 and VEGF levels. Itraconazole may prove beneficial for treating CNV as an alternative or adjunct to other therapies.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2011-2012

This review is the seventh update of the original article published in 1999 on the application of MALDI mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2012. General aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, and fragmentation are covered in the first part of the review and applications to various structural types constitute the remainder. The main groups of compound are oligo- and poly-saccharides, glycoproteins, glycolipids, glycosides, and biopharmaceuticals. Much of this material is presented in tabular form. Also discussed are medical and industrial applications of the technique, studies of enzyme reactions, and applications to chemical synthesis. © 2015 Wiley Periodicals, Inc. Mass Spec Rev 36:255-422, 2017.

Small molecule-mediated inhibition of myofibroblast transdifferentiation for the treatment of fibrosis

Fibrosis, a disease in which excessive amounts of connective tissue accumulate in response to physical damage and/or inflammatory insult, affects nearly every tissue in the body and can progress to a state of organ malfunction and death. A hallmark of fibrotic disease is the excessive accumulation of extracellular matrix-secreting activated myofibroblasts (MFBs) in place of functional parenchymal cells. As such, the identification of agents that selectively inhibit the transdifferentiation process leading to the formation of MFBs represents an attractive approach for the treatment of diverse fibrosis-related diseases. Herein we report the development of a high throughput image-based screen using primary hepatic stellate cells that identified the antifungal drug itraconazole (ITA) as an inhibitor of MFB cell fate in resident fibroblasts derived from multiple murine and human tissues (i.e., lung, liver, heart, and skin). Chemical optimization of ITA led to a molecule (CBR-096-4) devoid of antifungal and human cytochrome P450 inhibitory activity with excellent pharmacokinetics, safety, and efficacy in rodent models of lung, liver, and skin fibrosis. These findings may serve to provide a strategy for the safe and effective treatment of a broad range of fibrosis-related diseases.

Uncovering oxysterol-binding protein (OSBP) as a target of the anti-enteroviral compound TTP-8307

The genus Enterovirus (e.g. poliovirus, coxsackievirus, rhinovirus) of the Picornaviridae family of positive-strand RNA viruses includes many important pathogens linked to a range of acute and chronic diseases for which no approved antiviral therapy is available. Targeting a step in the life cycle that is highly conserved provides an attractive strategy for developing broad-range inhibitors of enterovirus infection. A step that is currently explored as a target for the development of antivirals is the formation of replication organelles, which support replication of the viral genome. To build replication organelles, enteroviruses rewire cellular machinery and hijack lipid homeostasis pathways. For example, enteroviruses exploit the PI4KIIIβ-PI4P-OSBP pathway to direct cholesterol to replication organelles. Here, we uncover that TTP-8307, a known enterovirus replication inhibitor, acts through the PI4KIIIβ-PI4P-OSBP pathway by directly inhibiting OSBP activity. However, despite a shared mechanism of TTP-8307 with established OSBP inhibitors (itraconazole and OSW-1), we identify a number of notable differences between these compounds. The antiviral activity of TTP-8307 extends to other viruses that require OSBP, namely the picornavirus encephalomyocarditis virus and the flavivirus hepatitis C virus.

Synthetic Small Molecule Inhibitors of Hh Signaling As Anti-Cancer Chemotherapeutics

The hedgehog (Hh) pathway is a developmental signaling pathway that is essential to the proper embryonic development of many vertebrate systems. Dysregulation of Hh signaling has been implicated as a causative factor in the development and progression of several forms of human cancer. As such, the development of small molecule inhibitors of Hh signaling as potential anti-cancer chemotherapeutics has been a major area of research interest in both academics and industry over the past ten years. Through these efforts, synthetic small molecules that target multiple components of the Hh pathway have been identified and advanced to preclinical or clinical development. The goal of this review is to provide an update on the current status of several synthetic small molecule Hh pathway inhibitors and explore the potential of several recently disclosed inhibitory scaffolds.

Itraconazole therapy in a pancreatic adenocarcinoma patient: A case report

OBJECTIVE

To report the case of a patient receiving itraconazole for the treatment of histoplasmosis and his subsequent reduction in pancreatic tumor size.

CASE SUMMARY

A 64-year-old male was diagnosed with Stage III locally advanced unresectable pancreatic adenocarcinoma. The patient was administered radiation plus chemotherapy, which included cisplatin and capecitabine. Upon restaging, the patient's tumor was again determined to be unresectable; therefore, palliative chemotherapy treatments were initiated, which included gemcitabine and erlotinib. After two gemcitabine cycles, he was admitted to the hospital because of loss of motor function due to spinal cord hemisection. After the surgery, the patient became neutropenic because of previous chemotherapy cycle and developed disseminated histoplasmosis. After he received his nine-month course of itraconazole, the pancreatic cancer was readdressed and he was then deemed to be resectable and had a Whipple procedure. Over the next several years, he showed no evidence of pancreatic metastases or relapse.

DISCUSSION

Itraconazole has been shown to have many mechanisms by which it could potentially suppress tumor cell growth, which includes inhibition of the Hedgehog pathway, vascular endothelial growth factor receptor-2, and P-glycoprotein efflux pump. This azole antifungal has been studied in small patient populations with various types of cancers. Studies of basal cell carcinoma, nonsmall cell lung cancer, ovarian cancer, and malignant pleural mesothelioma have shown favorable results suggesting that more study of itraconazole is warranted to decide its clinical utility.

CONCLUSION

There would need to be much more research performed to determine if this agent had a role as a chemotherapy agent; however, health care professionals should be aware of itraconazole's potential antineoplastic mechanisms.

Current trends in medical management of infantile hemangioma

PURPOSE OF REVIEW

Infantile hemangiomas are the most common benign, soft-tissue tumors of infancy, affecting between 5 and 10% of newborns, and up to 30% of premature infants. Morbidity may include disfigurement and scarring, difficulty in feeding, ulceration, vision loss, airway compromise, congestive heart failure, and death. Advances in understanding the pathogenesis of infantile hemangiomas have given rise to a number of promising treatments. This article reviews the current options for medical management of infantile hemangiomas.

RECENT FINDINGS

In the proliferative phase of infantile hemangiomas, vascular endothelial growth factor and basic fibroblast growth factor have shown increased expression, and vascular endothelial growth factor expression has been up-regulated by adrenergic stimulation. Moreover, the role of the renin-angiotensin system in the pathogenesis of infantile hemangiomas has been demonstrated. Numerous medical options have been under investigation. Since 2008, propanolol has become the first-line therapy, whereas other medical treatments are used less frequently or when propanolol is unsuccessful.

SUMMARY

Propranolol has been recently adopted as the first-line medical treatment for complicated infantile hemangiomas. Although emerging treatment options and modalities have shown promising results, there need to be high-quality multicenter randomized trials to support these preliminary data.

Propranolol for infantile hemangioma: Current state of affairs

Infantile hemangioma (IH) is the most common benign tumor seen in infancy. This review provides up-to-date information on the pathophysiology, variations in clinical presentation, and natural history of IH, elaborating on associated anomalies, such as PHACE(S) syndrome and LUMBAR syndrome. Because of the benign and self-limiting characteristics seen in more than 90% of cases of IH, a conservative approach is usually chosen. However, some circumstances, such as ulceration, vision loss, breathing difficulties, or potential disfigurement, will require treatment during the proliferative phase. For decades, treatment of IH has primarily consisted of corticosteroids or surgery. Since 2008, propranolol has become the treatment of first choice. In this article, we bring to light the crucial changes in the treatment of IH over the past years. To date, there is still a lack of data on the possible long-term effects of propranolol treatment in young infants. A theoretical probability of the central nervous system being affected (that is, impairment of short- and long-term memory, psychomotor function, sleep quality, and mood) has recently been suggested. This review highlights research topics concerning these long-term adverse effects. Finally, information is provided on the potential instruments to measure IH severity and activity in clinical trials and/or in clinical practice and the recently developed and first-validated IH-specific quality-of-life questionnaire.

2-Deoxy-Glucose Downregulates Endothelial AKT and ERK via Interference with N-Linked Glycosylation, Induction of Endoplasmic Reticulum Stress, and GSK3β Activation

Interference with endothelial cell metabolism is a promising, yet unexploited strategy for angiogenesis inhibition. We reported that the glucose analogue 2-deoxy-D-glucose (2-DG) inhibits angiogenesis at significantly lower concentrations than those required for tumor cytotoxicity. Here, we found that hypersensitivity to 2-DG in endothelial cells is not associated with enhanced drug uptake compared with tumor cells, but with time-dependent, endothelial-selective inhibition of AKT and ERK phosphorylation. Downregulation of these critical survival pathways is shown to be due to 2-DG's interference with N-linked glycosylation, leading to alterations in VEGFR2 (and downstream signaling) as well as induction of endoplasmic reticulum (ER) stress, GSK3β activation, and apoptosis. In vivo, periocular administration of 2-DG in LHBETATAG mice was associated with significant reduction of newly formed (CD105(+)) tumor capillaries, ER stress (GRP 78 expression), and endothelial apoptosis (TUNEL). These findings uniquely link N-linked glycosylation inhibition, ER stress, and ERK/AKT downregulation in endothelial cells, and provide a novel drug development strategy to overcome resistance mechanisms to currently available antiangiogenic agents.

Immunosuppressive drugs affect high-mannose/hybrid N-glycans on human allostimulated leukocytes

N-glycosylation plays an important role in the majority of physiological and pathological processes occurring in the immune system. Alteration of the type and abundance of glycans is an element of lymphocyte differentiation; it is also common in the development of immune-mediated inflammatory diseases. The N-glycosylation process is very sensitive to different environmental agents, among them the pharmacological environment of immunosuppressive drugs. Some results show that high-mannose oligosaccharides have the ability to suppress different stages of the immune response. We evaluated the effects of cyclosporin A (CsA) and rapamycin (Rapa) on high-mannose/hybrid-type glycosylation in human leukocytes activated in a two-way mixed leukocyte reaction (MLR). CsA significantly reduced the number of leukocytes covered by high-mannose/hybrid N-glycans, and the synergistic action of CsA and Rapa led to an increase of these structures on the remaining leukocytes. This is the first study indicating that β1 and β3 integrins bearing high-mannose/hybrid structures are affected by Rapa and CsA. Rapa taken separately and together with CsA changed the expression of β1 and β3 integrins and, by regulating the protein amount, increased the oligomannose/hybrid-type N-glycosylation on the leukocyte surface. We suggest that the changes in the glycosylation profile of leukocytes may promote the development of tolerance in transplantation.

The anti-angiogenic action of 2-deoxyglucose involves attenuation of VEGFR2 signaling and MMP-2 expression in HUVECs

AIMS

2-Deoxyglucose (2-DG) is a glucose analogue and has been shown to inhibit angiogenesis in human umbilical vascular endothelial cells (HUVECs) through interference with N-linked glycosylation. However, the anti-angiogenic mechanisms of 2-DG are not fully elucidated.

MAIN METHODS

We first employed an ex vivo rat aortic ring model to substantiate the anti-angiogenic action of 2-DG and then used HUVECs to investigate the molecular mechanism underlying such an action.

KEY FINDINGS

Results reveal that 2-DG (0.05-1.0mM) significantly inhibited tube formation in both rat aortic rings and HUVECs. 2-DG (0.1-1.0mM) also significantly inhibited cell invasion and migration, as well as the activity and mRNA and protein expression of matrix metalloproteinase (MMP)-2 in HUVECs. In addition, 2-DG (1.0mM) significantly inhibited mRNA and protein expression of vascular endothelial growth receptor 2 (VEGFR2) in a time-dependent manner. 2-DG also significantly inhibited the phosphorylation of the focal adhesion kinase (FAK) and mitogen-activated protein kinase (p38), the downstream molecules of VEGFR2. The effects of 2-DG on tube formation, MMP-2 activity, and VEGFR2 protein expression in HUVECs were reversed by mannose, an N-linked glycosylation precursor. Mannose also reversed 2-DG-induced accumulation of VEGFR2 in the endoplasmic reticulum.

SIGNIFICANCE

This ex vivo and in vitro study demonstrates that 2-DG inhibits angiogenesis with an action involving attenuation of VEGFR2 signaling and MMP-2 expression, possibly resulting from interference with N-linked glycosylation of VEGFR2. Further studies are needed to show that 2-DG inhibits VEGF-mediated angiogenesis or that the actual status of N-glycosylation of VEGFR2 is affected by the treatment.

CUSP9* treatment protocol for recurrent glioblastoma: aprepitant, artesunate, auranofin, captopril, celecoxib, disulfiram, itraconazole, ritonavir, sertraline augmenting continuous low dose temozolomide

CUSP9 treatment protocol for recurrent glioblastoma was published one year ago. We now present a slight modification, designated CUSP9*. CUSP9* drugs--aprepitant, artesunate, auranofin, captopril, celecoxib, disulfiram, itraconazole, sertraline, ritonavir, are all widely approved by regulatory authorities, marketed for non-cancer indications. Each drug inhibits one or more important growth-enhancing pathways used by glioblastoma. By blocking survival paths, the aim is to render temozolomide, the current standard cytotoxic drug used in primary glioblastoma treatment, more effective. Although esthetically unpleasing to use so many drugs at once, the closely similar drugs of the original CUSP9 used together have been well-tolerated when given on a compassionate-use basis in the cases that have come to our attention so far. We expect similarly good tolerability for CUSP9*. The combined action of this suite of drugs blocks signaling at, or the activity of, AKT phosphorylation, aldehyde dehydrogenase, angiotensin converting enzyme, carbonic anhydrase -2,- 9, -12, cyclooxygenase-1 and -2, cathepsin B, Hedgehog, interleukin-6, 5-lipoxygenase, matrix metalloproteinase -2 and -9, mammalian target of rapamycin, neurokinin-1, p-gp efflux pump, thioredoxin reductase, tissue factor, 20 kDa translationally controlled tumor protein, and vascular endothelial growth factor. We believe that given the current prognosis after a glioblastoma has recurred, a trial of CUSP9* is warranted.

β1, 4-N-acetylgalactosaminyltransferase III modulates cancer stemness through EGFR signaling pathway in colon cancer cells

Cancer stem cells are cancer cells characterized with tumor initiating capacity. β1,4-N-acetylgalactosaminyltransferase III (B4GALNT3) synthesizes GalNAcβ1-4GlcNAc (LacdiNAc) which contributes to self-renewal of mouse embryonic stem cells. We previously showed that B4GALNT3 overexpression enhances colon cancer cell malignant phenotypes in vitro and in vivo. However, the role of B4GALNT3 in cancer stemness remains unclear. We found that B4GALNT3 expression was positively correlated with advanced stages and poor survival in colorectal cancer patients. Knockdown of B4GALNT3 using small interfering (si) RNAs in colon cancer cell lines (HCT116, SW480, HCT15, and HT29 cells) decreased sphere formation and the expression of stem cell markers, OCT4 and NANOG. The expression of B4GALNT3 was upregulated in colonospheres. Interestingly, we found that B4GALNT3 primarily modified N-glycans of EGFR with LacdiNAc by Wisteria floribunda agglutinin (WFA) pull down assays. B4GALNT3 knockdown suppressed EGF-induced phosphorylation of EGFR and its downstream signaling molecules. Furthermore, EGF-induced degradation of EGFR was facilitated. In addition, EGF-induced migration and invasion were significantly suppressed by B4GALNT3 knockdown. Taken together, these data suggest B4GALNT3 regulates cancer stemness and the invasive properties of colon cancer cells through modifying EGFR glycosylation and signaling. Our results provide novel insights into the role of LacdiNAc in colorectal cancer development.

Repurposing Drugs in Oncology (ReDO)-itraconazole as an anti-cancer agent

Itraconazole, a common triazole anti-fungal drug in widespread clinical use, has evidence of clinical activity that is of interest in oncology. There is evidence that at the clinically relevant doses, itraconazole has potent anti-angiogenic activity, and that it can inhibit the Hedgehog signalling pathway and may also induce autophagic growth arrest. The evidence for these anticancer effects, in vitro, in vivo, and clinical are summarised, and the putative mechanisms of their action outlined. Clinical trials have shown that patients with prostate, lung, and basal cell carcinoma have benefited from treatment with itraconazole, and there are additional reports of activity in leukaemia, ovarian, breast, and pancreatic cancers. Given the evidence presented, a case is made that itraconazole warrants further clinical investigation as an anti- cancer agent. Additionally, based on the properties summarised previously, it is proposed that itraconazole may synergise with a range of other drugs to enhance the anti-cancer effect, and some of these possible combinations are presented in the supplementary materials accompanying this paper.

The effects of amphotericin B on angiogenesis in chick chorioallantoic membrane

OBJECTIVE

Amphotericin B (AmB) is widely used as a mainstay in the treatment of sight-threatening fungal endophthalmitis. From the time that itraconazole was discovered to have a previously unknown anti-angiogenic activity, we have suspected that AmB may have possible effects on ocular angiogenesis. The purpose of this study was to evaluate the in vivo anti-angiogenic effect of AmB in the chick chorioallantoic membrane (CAM) model.

MATERIALS AND METHODS

Atak-S type fertilized eggs obtained from the Poultry Institution were used. The eggs were kept under 37 °C at 85-90% relative humidity throughout the experiment. Amphotericin B was prepared in two different concentrations (AmB 125 μg/1 mL and 0.125 μg/1 mL). The CAMs treated with sterile distilled water was specified as controls. About 0.1 mL of each containing 12.5 and 0.0125 µg of AmB, respectively, were dropped to CAM surface. Thirteen eggs were used for each group. The results were evaluated at the 48th hour of the administration of the drugs and recorded by digital camera.

RESULTS

A reduction of angiogenesis in CAM area which treated with 125 μg/1 mL of AmB was appreciable macroscopically. The affected areas showed impaired radial arrangement of small vessels with the presence of avascular zone at periphery. The dose of 0.125 μg/1 mL AmB did not show any visible anti-angiogenic effect. Numerous blood vessels with a radially arranged pattern developed toward the periphery after 48 h of treatment. In the CAMs that treated with distilled water, physiological angiogenesis was observed in allantoic vessels. Vessel formation seems to be similar in CAMs treated with 0.125 μg/1 mL AmB with the presence of visibly non-malformed alive embryos.

CONCLUSIONS

The present study gives the impression that AmB has the capacity to serve as an anti-angiogenic treatment. As it is a preliminary CAM study only, further studies on both animals and humans are required.

Inhibition of angiogenesis by selective estrogen receptor modulators through blockade of cholesterol trafficking rather than estrogen receptor antagonism

Selective estrogen receptor modulators (SERM) including tamoxifen are known to inhibit angiogenesis. However, the underlying mechanism, which is independent of their action on the estrogen receptor (ER), has remained largely unknown. In the present study, we found that tamoxifen and other SERM inhibited cholesterol trafficking in endothelial cells, causing a hyper-accumulation of cholesterol in late endosomes/lysosomes. Inhibition of cholesterol trafficking by tamoxifen was accompanied by abnormal subcellular distribution of vascular endothelial growth factor receptor-2 (VEGFR2) and inhibition of the terminal glycosylation of the receptor. Tamoxifen also caused perinuclear positioning of lysosomes, which in turn trapped the mammalian target of rapamycin (mTOR) in the perinuclear region of endothelial cells. Abnormal distribution of VEGFR2 and mTOR and inhibition of VEGFR2 and mTOR activities by tamoxifen were significantly reversed by addition of cholesterol-cyclodextrin complex to the culture media of endothelial cells. Moreover, high concentrations of tamoxifen inhibited endothelial and breast cancer cell proliferation in a cholesterol-dependent, but ER-independent, manner. Together, these results unraveled a previously unrecognized mechanism of angiogenesis inhibition by tamoxifen and other SERM, implicating cholesterol trafficking as an attractive therapeutic target for cancer treatment.

The cholesterol biosynthesis enzyme oxidosqualene cyclase is a new target to impair tumour angiogenesis and metastasis dissemination

Aberrant cholesterol homeostasis and biosynthesis has been observed in different tumour types. This paper investigates the role of the post-squalenic enzyme of cholesterol biosynthesis, oxidosqualene cyclase (OSC), in regulating tumour angiogenesis and metastasis dissemination in mouse models of cancer. We showed that Ro 48-8071, a selective inhibitor of OSC, reduced vascular density and increased pericyte coverage, with a consequent inhibition of tumour growth in a spontaneous mouse model of pancreatic tumour (RIP-Tag2) and two metastatic mouse models of human colon carcinoma (HCT116) and pancreatic adenocarcinoma (HPAF-II). Remarkably, the inhibition of OSC hampered metastasis formation in HCT116 and HPAF-II models. Ro 48-8071 induced tumour vessel normalization and enhanced the anti-tumoral and anti-metastatic effects of 5-fluorouracil (5-FU) in HCT116 mice. Ro 48-8071 exerted a strong anti-angiogenic activity by impairing endothelial cell adhesion and migration, and by blocking vessel formation in angiogenesis assays. OSC inhibition specifically interfered with the PI3K pathway. According to in vitro results, Ro 48-8071 specifically inhibited Akt phosphorylation in both cancer cells and tumour vasculature in all treated models. Thus, our results unveil a crucial role of OSC in the regulation of cancer progression and tumour angiogenesis, and indicate Ro 48-8071 as a potential novel anti-angiogenic and anti-metastatic drug.

Itraconazole, a commonly used antifungal, inhibits Fcγ receptor-mediated phagocytosis: alteration of Fcγ receptor glycosylation and gene expression

Itraconazole (ICZ) is commonly used for the treatment of fungal infections, particularly in immunocompromised patients. In addition, ICZ has been recently found to have antiangiogenic effects and is currently being tested as a new chemotherapeutic agent in several cancer clinical trials. We have previously shown that ICZ impaired complex N-linked glycosylation processing, leading to the accumulation of high-mannose glycoproteins on the surface of macrophages (Møs). This investigation was directed at determining the effects of ICZ on phagocytosis as a major function of Møs. We found a significant decrease in the phagocytosis of opsonized bacterial particles in ICZ-treated murine Møs in comparison with nontreated Møs. Furthermore, the impairment of phagocytosis was associated with a decrease in cell surface expression of Fcγ receptors (FcγRs) as well as alteration of their glycosylation pattern. Concomitantly, a reduction in all three isoforms of the FcγR family (i.e., Fcgr1, Fcgr2, and Fcgr3) mRNA levels was observed after incubation with ICZ. The effect of ICZ on phagocytosis and FcγR expression was reversed by addition of low-density lipoprotein. These studies indicate that ICZ treatment certainly has a dramatic effect on macrophage function, which could result in a potential impairment of the immune system';s ability to respond to pathogens and may lead to an elevated incidence of infections.

Itraconazole inhibits enterovirus replication by targeting the oxysterol-binding protein

Itraconazole (ITZ) is a well-known antifungal agent that also has anticancer activity. In this study, we identify ITZ as a broad-spectrum inhibitor of enteroviruses (e.g., poliovirus, coxsackievirus, enterovirus-71, rhinovirus). We demonstrate that ITZ inhibits viral RNA replication by targeting oxysterol-binding protein (OSBP) and OSBP-related protein 4 (ORP4). Consistently, OSW-1, a specific OSBP/ORP4 antagonist, also inhibits enterovirus replication. Knockdown of OSBP inhibits virus replication, whereas overexpression of OSBP or ORP4 counteracts the antiviral effects of ITZ and OSW-1. ITZ binds OSBP and inhibits its function, i.e., shuttling of cholesterol and phosphatidylinositol-4-phosphate between membranes, thereby likely perturbing the virus-induced membrane alterations essential for viral replication organelle formation. ITZ also inhibits hepatitis C virus replication, which also relies on OSBP. Together, these data implicate OSBP/ORP4 as molecular targets of ITZ and point to an essential role of OSBP/ORP4-mediated lipid exchange in virus replication that can be targeted by antiviral drugs.

Repurposing drugs in oncology (ReDO)-cimetidine as an anti-cancer agent

Cimetidine, the first H₂ receptor antagonist in widespread clinical use, has anti-cancer properties that have been elucidated in a broad range of pre-clinical and clinical studies for a number of different cancer types. These data are summarised and discussed in relation to a number of distinct mechanisms of action. Based on the evidence presented, it is proposed that cimetidine would synergise with a range of other drugs, including existing chemotherapeutics, and that further exploration of the potential of cimetidine as an anti-cancer therapeutic is warranted. Furthermore, there is compelling evidence that cimetidine administration during the peri-operative period may provide a survival benefit in some cancers. A number of possible combinations with other drugs are discussed in the supplementary material accompanying this paper.

Antiangiogenic effect of itraconazole on corneal neovascularization: a pilot experimental investigation

PURPOSE

To investigate the antiangiogenic effect of itraconazole for the prevention of experimentally induced corneal neovascularization and whether the efficacy depends on the route of administration.

MATERIALS AND METHODS

Thirty-six rats were randomly divided into 6 groups with 6 rats in each group. Chemical cauterization of the cornea was performed using silver nitrate/potassium nitrate sticks, and the rats were subsequently treated daily with topical (10 mg/ml), subconjunctival (10 mg/ml) or intraperitoneal (19 mg/kg) itraconazole for 7 days. Control rats received topical, subconjunctival or intraperitoneal 0.9% saline. On the 8th day of the experiment, the rat corneas were photographed to determine the percentage area of the cornea covered by neovascularization. The maximum density of corneal neovascularization was determined by microscopy.

RESULTS

The median percentage of corneal neovascularization for group 1 was 31.5% (95% confidence interval, 27.5-35.5%); in group 3, it was 32% (23.5-39.8%); in group 5, it was 47% (36.3-60.0%). The percentages of corneal neovascularization in groups 2, 4 and 6 (the control groups) were 70% (95% confidence interval, 60.7-77.3%), 69% (63.0-77.7%) and 68% (56.5-78.5%), respectively. The area of neovascularization was smaller after itraconazole treatment as compared to saline treatment. Further, the area of neovascularization was smaller after topical and subconjunctival administration than after intraperitoneal administration. Histological evaluation of the corneas showed the most extensive corneal neovascularization in the control group. No local or systemic adverse effects were seen from either treatment group.

CONCLUSION

Itraconazole reduces corneal neovascularization shortly after chemical burn. However, a larger experimental study is necessary to confirm the data of this investigation.

Emerging roles of post-translational modifications in signal transduction and angiogenesis

The vascular endothelial growth factor receptor-2 (VEGFR-2) belongs to the family of receptor tyrosine kinases and is a key player in vasculogenesis and pathological angiogenesis. An emerging picture of PTMs of VEGFR-2 suggests that they play central roles in generating a highly dynamic and complex signaling system that regulates key angiogenic responses ranging from endothelial cell differentiation, proliferation, migration to permeability. Recent MS analysis of VEGFR-2 uncovered previously unrecognized PTMs on VEGFR-2 with a distinct function. The ligand binding extracellular domain of VEGFR-2 is composed of seven immunoglobulin-like domains highly decorated with N-glycosylation, while its cytoplasmic domain is subject to multiple PTMs including Tyr, Ser/Thr phosphorylation, Arg and Lys methylation, acetylation and ubiquitination. Here we review the PTMs on VEGFR-2, their importance in angiogenic signaling relays and possible novel therapeutic potentials.

Electrochemical monitoring of an important biomarker and target protein: VEGFR2 in cell lysates

Vascular endothelial growth factor receptor 2 (VEGFR2) is a potential cell-type biomarker in clinical diagnoses. Besides, it's the target protein of many tyrosine kinase inhibitors and its expression significantly associates with clinical performance of these inhibitors. VEGFR2 detection provides an early warning for diseases and a basis for therapy and drug screening. Some methods have been developed for VEGFR2 determination. However, they are usually performed indirectly and complexly. Herein, an electrochemical biosensing platform for VEGFR2 analysis has been first proposed. It can detect the total concentrations of the VEGFR2 protein in cells lysates directly and can be used to monitor the changes of VEGFR2 expression levels induced by treatments of different inhibitors. Moreover, the inhibitor-VEGFR2 interactions are illuminated through theoretical simulation. The simulation results agree well with the experimental data, indicating the veracity of the proposed method. The electrochemical detection methodology for VEGFR2 would be promising in clinical diagnosis and drug screening.

Recent advances in drug repositioning for the discovery of new anticancer drugs

Drug repositioning (also referred to as drug repurposing), the process of finding new uses of existing drugs, has been gaining popularity in recent years. The availability of several established clinical drug libraries and rapid advances in disease biology, genomics and bioinformatics has accelerated the pace of both activity-based and in silico drug repositioning. Drug repositioning has attracted particular attention from the communities engaged in anticancer drug discovery due to the combination of great demand for new anticancer drugs and the availability of a wide variety of cell- and target-based screening assays. With the successful clinical introduction of a number of non-cancer drugs for cancer treatment, drug repositioning now became a powerful alternative strategy to discover and develop novel anticancer drug candidates from the existing drug space. In this review, recent successful examples of drug repositioning for anticancer drug discovery from non-cancer drugs will be discussed.

Targeting of the Hedgehog signal transduction pathway suppresses survival of malignant pleural mesothelioma cells in vitro

OBJECTIVE

The present study sought to determine whether the Hedgehog (Hh) pathway is active and regulates the cell growth of cultured malignant pleural mesothelioma (MPM) cells and to evaluate the efficacy of pathway blockade using smoothened (SMO) antagonists (SMO inhibitor GDC-0449 or the antifungal drug itraconazole [ITRA]) or Gli inhibitors (GANT61 or the antileukemia drug arsenic trioxide [ATO]) in suppressing MPM viability.

METHODS

Selective knockdown of SMO to inhibit Hh signaling was achieved by small interfering RNA in 3 representative MPM cells. The growth inhibitory effect of GDC-0449, ITRA, GANT61, and ATO was evaluated in 8 MPM lines, with cell viability quantified using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell death was determined by annexinV/propidium iodide staining and flow cytometry.

RESULTS

SMO small interfering RNA mediated a two- to more than fivefold reduction of SMO and Gli1 gene expression as determined by real-time quantitative reverse-transcriptase polymerase chain reaction, indicating significant Hh pathway blockade. This was associated with significantly reduced cell viability (34% ± 7% to 61% ± 14% of nontarget small interfering RNA controls; P = .0024 to P = .043). Treating MPM cells with Hh inhibitors resulted in a 1.5- to 4-fold reduction of Gli1 expression. These 4 Hh antagonists strongly suppressed MPM cell viability. More importantly, ITRA, ATO, GANT61 induced significant apoptosis in the representative MPM cells.

CONCLUSIONS

Hh signaling is active in MPM and regulates cell viability. ATO and ITRA were as effective as the prototypic SMO inhibitor GDC-0449 and the Gli inhibitor GANT61 in suppressing Hh signaling in MPM cells. Pharmaceutical agents Food and Drug Administration-approved for other indications but recently found to have anti-Hh activity, such as ATO or ITRA, could be repurposed to treat MPM.

Antitumor effects of Endostar on non-Hodgkin's lymphoma by regulating endothelial progenitor cells through protein kinase B-dependent pathway

Endothelial progenitor cells (EPCs) play an important role in non-Hodgkin's lymphoma (NHL) development. Endostar is an anti-angiogenic drug designed to stop cancer by nullifying a tumor's ability to obtain oxygen and nutrients. In this study, we examined the anti-angiogenic activities of Endostar on NHL cell lines and murine xenograft model of NHL in vitro and in vivo, respectively, and explored the underlying antiangiogenic mechanism of Endostar. Results showed that Endostar may inhibit the EPC proliferation by reducing the expression of p-protein kinase B, but not p-ERK expression. Our finding could lead to a better understanding of the effects of Endostar on NHL.

Itraconazole and arsenic trioxide inhibit Hedgehog pathway activation and tumor growth associated with acquired resistance to smoothened antagonists

Recognition of the multiple roles of Hedgehog signaling in cancer has prompted intensive efforts to develop targeted pathway inhibitors. Leading inhibitors in clinical development act by binding to a common site within Smoothened, a critical pathway component. Acquired Smoothened mutations, including SMO(D477G), confer resistance to these inhibitors. Here, we report that itraconazole and arsenic trioxide, two agents in clinical use that inhibit Hedgehog signaling by mechanisms distinct from that of current Smoothened antagonists, retain inhibitory activity in vitro in the context of all reported resistance-conferring Smoothened mutants and GLI2 overexpression. Itraconazole and arsenic trioxide, alone or in combination, inhibit the growth of medulloblastoma and basal cell carcinoma in vivo, and prolong survival of mice with intracranial drug-resistant SMO(D477G) medulloblastoma.

Hedgehog signaling pathway and its targets for treatment in basal cell carcinoma

Basal cell carcinoma (BCC) of the skin is the most common type of cancer and accounts for up to 40% of all cancers in the US, with a growing incidence rate over recent decades in all developed countries. Surgery is curative for most patients, although it leaves unaesthetic scars, but those that develop locally advanced or metastatic BCC require different therapeutic approaches. Furthermore, patients with BCC present a high risk of developing additional tumors. The increasing economic burden and the morbidity of BCC render primary interest in the development of targeted treatments for this disease. Among the molecular signals involved in the development of BCC, the critical role of the morphogenetic Hedgehog (Hh) pathway has become evident. This pathway is found altered and activated in almost all BCCs, both sporadic and inherited. Given the centrality of the Hh pathway in the pathophysiology of BCC, the primary efforts to identify molecular targets for the topical or systemic treatment of this cancer have focused on the Hh components. Several Hh inhibitors have been so far identified - from the first identified natural cyclopamine to the recently Food and Drug Administration-approved synthetic vismodegib - most of which target the Hh receptor Smoothened (either its function or its translocation to the primary cilium). Other molecules await further characterization (bisamide compounds), while drugs currently approved for other diseases such as itraconazole (an antimicotic agent) and vitamin D3 have been tested on BCC with encouraging results. The outcomes of the numerous ongoing clinical trials are expected to expand the field in the very near future. Further research is needed to obtain drugs targeting downstream components of the Hh pathway (eg, Gli) or to exploit combinatorial therapies (eg, with phosphatidylinositol 3-kinase inhibitors or retinoids) in order to overcome potential drug resistance.

Angiogenesis impairment in diabetes: role of methylglyoxal-induced receptor for advanced glycation endproducts, autophagy and vascular endothelial growth factor receptor 2

Diabetes impairs physiological angiogenesis by molecular mechanisms that are not fully understood. Methylglyoxal (MGO), a metabolite of glycolysis, is increased in patients with diabetes. This study defined the role of MGO in angiogenesis impairment and tested the mechanism in diabetic animals. Endothelial cells and mouse aortas were subjected to Western blot analysis of vascular endothelial growth factor receptor 2 (VEGFR2) protein levels and angiogenesis evaluation by endothelial cell tube formation/migration and aortic ring assays. Incubation with MGO reduced VEGFR2 protein, but not mRNA, levels in a time and dose dependent manner. Genetic knockdown of the receptor for advanced glycation endproducts (RAGE) attenuated the reduction of VEGFR2. Overexpression of Glyoxalase 1, the enzyme that detoxifies MGO, reduced the MGO-protein adducts and prevented VEGFR2 reduction. The VEGFR2 reduction was associated with impaired angiogenesis. Suppression of autophagy either by inhibitors or siRNA, but not of the proteasome and caspase, normalized both the VEGFR2 protein levels and angiogenesis. Conversely, induction of autophagy either by rapamycin or overexpression of LC3 and Beclin-1 reduced VEGFR2 and angiogenesis. MGO increased endothelial LC3B and Beclin-1, markers of autophagy, which were accompanied by an increase of both autophagic flux (LC3 punctae) and co-immunoprecipitation of VEGFR2 with LC3. Pharmacological or genetic suppression of peroxynitrite (ONOO(-)) generation not only blocked the autophagy but also reversed the reduction of VEGFR2 and angiogenesis. Like MGO-treated aortas from normglycemic C57BL/6J mice, aortas from diabetic db/db and Akita mice presented reductions of angiogenesis or VEGFR2. Administration of either autophagy inhibitor ex vivo or superoxide scavenger in vivo abolished the reductions. Taken together, MGO reduces endothelial angiogenesis through RAGE-mediated, ONOO(-)dependent and autophagy-induced VEGFR2 degradation, which may represent a new mechanism for diabetic angiogenesis impairment.

Itraconazole: its possible role in inhibiting angiogenesis in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic, inflammatory, autoimmune disorder involving mainly synovial joints. It can progress to a severely debilitating form with pulmonary, renal and cardiovascular involvement. Currently, disease-modifying antirheumatic drugs (DMARDs) remain the gold standard pharmacological therapy for RA (along with nonsteroidal anti-inflammatory drugs and corticosteroids). However, DMARDs are more or less ineffective in the late phase of the disease and adverse effects often limit their use. Studies show that serum levels of vascular endothelial growth factor (VEGF) remain elevated throughout the course of RA. In experimental models, the administration of pro-angiogenic cytokines, such as VEGF or FGF, has been shown to increase the severity of the disease. Therefore, anti-angiogenic drugs such as bevacizumab (which is already being used as an anti-tumor agent) may play a significant role in longstanding RA. However, adverse effects such as hypertension, gastro-intestinal perforation and the high cost of bevacizumab are major concerns. A recent study suggests that itraconazole, an antifungal drug, has a role in selectively inhibiting angiogenesis and growth of tumor in non-small cell lung cancer. Hence, this drug may be beneficial in the treatment of RA, especially in the later phase when other modalities have failed, or as an adjuvant. To test our hypothesis, we propose a randomized, double-blinded trial in patients with longstanding RA. The control group receives the standard DMARD therapy plus placebo, while the case group receives itraconazole in addition to DMARD therapy. Serum and synovial VEGF levels, in both the control group and the case group, are compared and their correlation with the symptoms is judged. If the VEGF levels are lower and/or the symptoms are less severe in the case group, our hypothesis will be confirmed. Multi-institutional efforts are needed to confirm this hypothesis, as it is relatively new and trial data is limited.