Search

Glioblastoma multiforme (GBM) is known as the primary malignant and most devastating form of tumor found in the central nervous system of the adult population. The active pharmaceutical component in current chemotherapy regimens is mostly hydrophobic and poorly water-soluble, which hampers clinical implications. Nanodrug formulations using nanocarriers loaded with such drugs assisted in water dispersibility, improved cellular permeability, and drug efficacy at a low dose, thus adding to the overall practical value. Here, we successfully developed a water-dispersible and biocompatible nanocargo (GO-PEG) based on covalently modified graphene oxide (GO) with a 6- armed poly(ethylene glycol) amine dendrimer for effective loading of the two hydrophobic anticancer drug molecules, CPI444 and vatalanib. These drug molecules target adenosine receptor (A2AR), vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR), and type III stem cell receptor tyrosine kinase (c-KIT), which plays a crucial role in cancers. The effective cellular delivery of the drugs when loaded on GOPEG is attributed to the increased permeability of the drug-nanoconjugate formulation. We observed that this combinatorial drug treatment with nanocargo resulted in a significant reduction in the overall cell survival as supported by reduced calcium levels and stem cell markers such as Oct4 and Nanog, which are two of the prime factors for GBM stem cell proliferation. Furthermore, reduced expression of CD24 upon treatment with nanoformulation impeded cellular migration. Cellular assays confirmed inhibition of cell proliferation, migration, and angiogenic potential of GBM treated with GO-PEG-Drug conjugates. Ultimately, GBM U87 cells assumed programmed cell death at a very low concentration due to nanocarriermediated drug delivery along with the chosen combination of drugs. Together, this study demonstrated the advantage of GO-PEG mediated combined delivery of CPI444 and vatalanib drugs with increased permeability, a three-pronged combinatorial strategy toward effective GBM treatment. [ABSTRACT FROM AUTHOR]

Abstract Alzheimer’s disease (AD) is a highly prevalent neurodegenerative disease characterized by Aβ accumulation and tau hyperphosphorylation. Epidemiological evidence for a negative correlation between cancer and AD has led to the proposed use of tyrosine kinase inhibitors (TKIs) such as dasatinib and masitinib for AD, with reported beneficial effects in the AD brain. The TKI vatalanib inhibits angiogenesis by inhibiting vascular endothelial growth factor receptor (VEGFR). Although changes in VEGF and VEGFR have been documented in AD, the effect of vatalanib on AD pathology has not been investigated. In this study, the effects of vatalanib on tau phosphorylation and Aβ accumulation in 5xFAD mice, a model of AD, were evaluated by immunohistochemistry. Vatalanib administration significantly reduced tau phosphorylation at AT8 and AT100 by increasing p-GSK-3β (Ser9) in 5xFAD mice. In addition, vatalanib reduced the number and area of Aβ plaques in the cortex in 5xFAD mice. Our results suggest that vatalanib has potential as a regulator of AD pathology.

Summary: Purpose Combining small-molecule inhibitors of different targets was shown to be synergistic in preclinical studies. Testing this concept in clinical trials is, however, daunting due to challenges in toxicity management and efficacy assessment. This study attempted to evaluate the safety and efficacy of vatalanib plus everolimus in patients with advanced solid tumors and explore the utility of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) studies as a predictive biomarker. Patients and Methods This single-center, phase I trial containing 70 evaluable patients consisted of a dose escalation proportion based on the traditional "3 + 3" design (cohort IA and IB) and a dose expansion proportion (cohort IIA and IIB). Toxicity was evaluated using the Common Terminology Criteria of Adverse Events. Antitumor activity was assessed using the Modified Response Evaluation Criteria in Solid Tumors. Results The maximum tolerated doses were determined to be vatalanib 1250 mg once daily or 750 mg twice daily in combination with everolimus 10 mg once daily. No treatment-related death occurred. The most common toxicities were hypertriglyceridemia, hypercholesterolemia, fatigue, vomiting, nausea and diarrhea. There was no complete response. Nine patients (12.9%) had partial response (PR) and 41 (58.6%) had stable disease (SD). Significant antitumor activity was observed in neuroendocrine tumors with a disease-control rate (PR + SD) of 66.7% and other tumor types including renal cancer, melanoma, and non-small-cell lung cancer. Conclusions The combination of vatalanib and everolimus demonstrated reasonable toxicity and clinical activity. Future studies combining targeted therapies and incorporating biomarker analysis are warranted based on this phase I trial. [ABSTRACT FROM AUTHOR]

Summary: Introduction Vatalanib is an oral receptor tyrosine kinase inhibitor that blocks all known VEGF, PDGF, and c-Kit receptors. This phase I study evaluated the safety, tolerability, and biologic activity of the combination of vatalanib with pemetrexed disodium in patients with advanced solid tumors. Methods Patients were administered escalating twice daily doses of vatalanib in combination with pemetrexed disodium in 21-day cycles. A dose expansion cohort was enrolled to further define the maximum tolerated dose (MTD) and further evaluate efficacy. Results A total of 29 patients were enrolled in the study (dose escalation, 9; dose expansion, 20). Dose-limiting toxicities included grade 4 thrombocytopenia (6.9%) and febrile neutropenia, anorexia, constipation, and dehydration. Other common adverse events were fatigue (75%), nausea (66%), vomiting (48%), oral mucositis (31%) and diarrhea (28%). The majority of these toxicities were Grade 1–2. The MTD was reached at vatalanib 250 mg twice daily continuously combined with pemetrexed disodium 500 mg/m2 day 1. Overall, 2 patients (6.9%) had partial responses, 8 (27.6%) had stable disease for at least 4 cycles, 5 had progressive disease (17.2%) and 5 went off study before disease assessment. Conclusion The combination of vatalanib with pemetrexed disodium was feasible, but not well tolerated. The modest efficacy results are consistent with other results obtained from combinations of chemotherapy and a large number of VEGF tyrosine kinase inhibitors. This combination should not be developed further unless predictive biomarkers can be identified. [ABSTRACT FROM AUTHOR]

Although VEGF (vascular endothelial growth factor) inhibitors (VEGFIs), are effective anticancer therapies, they cause hypertension through unknown mechanisms. We questioned whether changes in vascular redox state may be important, because VEGF signaling involves nitric oxide (NO) and reactive oxygen species. Molecular mechanisms, including NOS, NADPH oxidase (Nox)-derived reactive oxygen species, antioxidant systems, and vasoconstrictor signaling pathways, were probed in human endothelial cells and vascular smooth muscle exposed to vatalanib, a VEGFI. Vascular functional effects of VEGFI were assessed ex vivo in mouse arteries. Cardiovascular and renal in vivo effects were studied in vatalanib- or gefitinib (EGFI [epidermal growth factor inhibitor])-treated mice. In endothelial cells, vatalanib decreased eNOS (Ser1177) phosphorylation and reduced NO and H2O2 production, responses associated with increased Nox-derived O2- and ONOO- formation. Inhibition of Nox1/4 (GKT137831) or Nox1 (NoxA1ds), prevented vatalanib-induced effects. Nrf-2 (nuclear factor erythroid 2-related factor 2) nuclear translocation and expression of Nrf-2-regulated antioxidant enzymes were variably downregulated by vatalanib. In human vascular smooth muscles, VEGFI increased Nox activity and stimulated Ca2+ influx and MLC20 phosphorylation. Acetylcholine-induced vasodilatation was impaired and U46619-induced vasoconstriction was enhanced by vatalanib, effects normalized by N-acetyl-cysteine and worsened by L-NAME. In vatalanib-, but not gefitinib-treated mice vasorelaxation was reduced and media:lumen ratio of mesenteric arteries was increased with associated increased cardiovascular and renal oxidative stress, decreased Nrf-2 activity and downregulation of antioxidant genes. We demonstrate that inhibition of VEGF signaling induces vascular dysfunction through redox-sensitive processes. Our findings identify Noxs and antioxidant enzymes as novel targets underling VEGFI-induced vascular dysfunction. These molecular processes may contribute to vascular toxicity and hypertension in VEGFI-treated patients. [ABSTRACT FROM AUTHOR]

Among the various consequence arising from lung injury, hepatic fibrosis is the most severe. Decreasing the effects of hepatic fibrosis remains one of the primary therapeutic challenges in hepatology. Dysfunction of hepatic sinusoidal endothelial cells is considered to be one of the initial events that occur in liver injury. Vascular endothelial growth factor signaling is involved in the progression of genotype changes. The aim of the present study was to determine the effect of the tyrosine kinase inhibitor, vatalanib, on hepatic fibrosis and hepatic sinusoidal capillarization in a carbon tetrachloride (CCl4)-induced mouse model of liver fibrosis. Liver fibrosis was induced in BALB/c mice using CCl4 by intraperitoneal injection for 6 weeks. The four experimental groups included a control, and three experimental groups involving administration of CCl4, vatalanib and a combination of the two. Histopathological staining and measuring live hydroxyproline content evaluated the extent of liver fibrosis. The expression of α-smooth muscle actin (SMA) and cluster of differentiation (CD) 34 was detected by immunohistochemistry. Collagen type I, α-SMA, transforming growth factor (TGF)-β1 and vascular endothelial growth factor receptor (VEGFR) expression levels were measured by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The average number of fenestrae per hepatic sinusoid was determined using transmission electron microscopy. Liver fibrosis scores and hydroxyproline content were decreased in both vatalanib groups. In addition, both doses of vatalanib decreased mRNA expression levels of hepatic α-SMA, TGF-β1, collagen-1, VEGFR1, and VEGFR2. Levels of α-SMA and CD34 protein were decreased in the vatalanib group compared with the CCl4 group. There were significant differences in the number of fenestrae per sinusoid between the groups. The present study identified that administration of vatalanib was associated with decreased liver fibrosis and hepatic sinusoidal capillarization in CCl4-induced mouse models, and is a potential compound for counteracting liver fibrosis. [ABSTRACT FROM AUTHOR]

Background: Searching for two-dimensional (2D) structural similarities is a useful tool to identify new active compounds in drug-discovery programs. However, as 2D similarity measures neglect important structural and functional features, similarity by 2D might be underestimated. In the present study, we used combined 2D and three-dimensional (3D) similarity comparisons to reveal possible new functions and/or side-effects of known bioactive compounds. Results: We utilised more than 10,000 compounds from the SuperTarget database with known inhibition values for twelve different anti-cancer targets. We performed all-against-all comparisons resulting in 2D similarity landscapes. Among the regions with low 2D similarity scores are inhibitors of vascular endothelial growth factor receptor (VEGFR) and inhibitors of poly ADP-ribose polymerase (PARP). To demonstrate that 3D landscape comparison can identify similarities, which are untraceable in 2D similarity comparisons, we analysed this region in more detail. This 3D analysis showed the unexpected structural similarity between inhibitors of VEGFR and inhibitors of PARP. Among the VEGFR inhibitors that show similarities to PARP inhibitors was Vatalanib, an oral "multi-targeted" small molecule protein kinase inhibitor being studied in phase-III clinical trials in cancer therapy. An in silico docking simulation and an in vitro HT universal colorimetric PARP assay confirmed that the VEGFR inhibitor Vatalanib exhibits off-target activity as a PARP inhibitor, broadening its mode of action. Conclusion: In contrast to the 2D-similarity search, the 3D-similarity landscape comparison identifies new functions and side effects of the known VEGFR inhibitor Vatalanib. [ABSTRACT FROM AUTHOR]