The coming of ramucirumab in the landscape of anti-angiogenic drugs: potential clinical and translational perspectives

Suppressing VEGF-A/VEGFR-2 Signaling Contributes to the Anti-Angiogenic Effects of PPE8, a Novel Naphthoquinone-Based Compound

Natural naphthoquinones and their derivatives exhibit a broad spectrum of pharmacological activities and have thus attracted much attention in modern drug discovery. However, it remains unclear whether naphthoquinones are potential drug candidates for anti-angiogenic agents. The aim of this study was to evaluate the anti-angiogenic properties of a novel naphthoquinone derivative, PPE8, and explore its underlying mechanisms. Determined by various assays including BrdU, migration, invasion, and tube formation analyses, PPE8 treatment resulted in the reduction of VEGF-A-induced proliferation, migration, and invasion, as well as tube formation in human umbilical vein endothelial cells (HUVECs). We also used an aorta ring sprouting assay, Matrigel plug assay, and immunoblotting analysis to examine PPE8’s ex vivo and in vivo anti-angiogenic activities and its actions on VEGF-A signaling. It has been revealed that PPE8 inhibited VEGF-A-induced micro vessel sprouting and was capable of suppressing angiogenesis in in vivo models. In addition, PPE8 inhibited VEGF receptor (VEGFR)-2, Src, FAK, ERK1/2, or AKT phosphorylation in HUVECs exposed to VEGF-A, and it also showed significant decline in xenograft tumor growth in vivo. Taken together, these observations indicated that PPE8 may target VEGF-A–VEGFR-2 signaling to reduce angiogenesis. It also supports the role of PPE8 as a potential drug candidate for the development of therapeutic agents in the treatment of angiogenesis-related diseases including cancer.

Anti-Angiogenetic and Anti-Lymphangiogenic Effects of a Novel 2-Aminobenzimidazole Derivative, MFB

Background and Purpose

Benzimidazoles have attracted much attention over the last few decades due to their broad-spectrum pharmacological properties. Increasing evidence is showing the potential use of benzimidazoles as anti-angiogenic agents, although the mechanisms that impact angiogenesis remain to be fully defined. In this study, we aim to investigate the anti-angiogenic mechanisms of MFB, a novel 2-aminobenzimidazole derivative, to develop a novel angiogenesis inhibitor.

Experimental Approach

MTT, BrdU, migration and invasion assays, and immunoblotting were employed to examine MFB’s effects on vascular endothelial growth factor (VEGF)-induced endothelial cell proliferation, migration, invasion, as well as signaling molecules activation. The anti-angiogenic effects of MFB were analyzed by tube formation, aorta ring sprouting, and matrigel plug assays. We also used a mouse model of lung metastasis to determine the MFB’s anti-metastatic effects.

Key Results

MFB suppressed cell proliferation, migration, invasion, and endothelial tube formation of VEGF-A-stimulated human umbilical vascular endothelial cells (HUVECs) or VEGF-C-stimulated lymphatic endothelial cells (LECs). MFB suppressed VEGF-A and VEGF-C signaling in HUVECs or LECs. In addition, MFB reduced VEGF-A- or tumor cells-induced neovascularization in vivo. MFB also diminished B16F10 melanoma lung metastasis. The molecular docking results further showed that MFB may bind to VEGFR-2 rather than VEGF-A with high affinity.

Conclusions and Implications

These observations indicated that MFB may target VEGF/VEGFR signaling to suppress angiogenesis and lymphangiogenesis. It also supports the role of MFB as a potential lead in developing novel agents for the treatment of angiogenesis- or lymphangiogenesis-associated diseases and cancer.

WMJ-S-001, a Novel Aliphatic Hydroxamate-Based Compound, Suppresses Lymphangiogenesis Through p38mapk-p53-survivin Signaling Cascade

Background and purpose: Angiogenesis and lymphangiogenesis are major routes for metastatic spread of tumor cells. It thus represent the rational targets for therapeutic intervention of cancer. Recently, we showed that a novel aliphatic hydroxamate-based compound, WMJ-S-001, exhibits anti-angiogenic, anti-inflammatory and anti-tumor properties. However, whether WMJ-S-001 is capable of suppressing lymphangiogenesis remains unclear. We are thus interested in exploring WMJ-S-001's anti-lymphangiogenic mechanisms in lymphatic endothelial cell (LECs).

Experimental approach: WMJ-S-001's effects on LEC proliferation, migration and invasion, as well as signaling molecules activation were analyzed by immunoblotting, flow-cytometry, MTT, BrdU, migration and invasion assays. We performed tube formation assay to examine WMJ-S-001's ex vivo anti-lymphangiogenic effects.

Key results: WMJ-S-001 inhibited serum-induced cell proliferation, migration, invasion in murine LECs (SV-LECs). WMJ-S-001 reduced the mRNA and protein levels of survivin. Survivin siRNA significantly suppressed serum-induced SV-LEC invasion. WMJ-S-001 induced p53 phosphorylation and increased its reporter activities. In addition, WMJ-S-001 increased p53 binding to the promoter region of survivin, while Sp1 binding to the region was decreased. WMJ-S-001 induced p38 mitogen-activated protein kinase (p38MAPK) activation. p38MPAK signaling blockade significantly inhibited p53 phosphorylation and restored survivin reduction in WMJ-S-001-stimulated SV-LCEs. Furthermore, WMJ-S-001 induced survivin reduction and inhibited cell proliferation, invasion and tube formation of primary human LECs.

Conclusions and Implications: These observations indicate that WMJ-S-001 may suppress lymphatic endothelial remodeling and reduce lymphangiogenesis through p38MAPK-p53-survivin signaling. It also suggests that WMJ-S-001 is a potential lead compound in developing novel agents for the treatment of lymphangiogenesis-associated diseases and cancer.

Trends and Challenges in Tumor Anti-Angiogenic Therapies

Excessive abnormal angiogenesis plays a pivotal role in tumor progression and is a hallmark of solid tumors. This process is driven by an imbalance between pro- and anti-angiogenic factors dominated by the tissue hypoxia-triggered overproduction of vascular endothelial growth factor (VEGF). VEGF-mediated signaling has quickly become one of the most promising anti-angiogenic therapeutic targets in oncology. Nevertheless, the clinical efficacy of this approach is severely limited in certain tumor types or shows only transient efficacy in patients. Acquired or intrinsic therapy resistance associated with anti-VEGF monotherapeutic approaches indicates the necessity of a paradigm change when targeting neoangiogenesis in solid tumors. In this context, the elaboration of the conceptual framework of “vessel normalization” might be a promising approach to increase the efficacy of anti-angiogenic therapies and the survival rates of patients. Indeed, the promotion of vessel maturation instead of regressing tumors by vaso-obliteration could result in reduced tumor hypoxia and improved drug delivery. The implementation of such anti-angiogenic strategies, however, faces several pitfalls due to the potential involvement of multiple pro-angiogenic factors and modulatory effects of the innate and adaptive immune system. Thus, effective treatments bypassing relapses associated with anti-VEGF monotherapies or breaking the intrinsic therapy resistance of solid tumors might use combination therapies or agents with a multimodal mode of action. This review enumerates some of the current approaches and possible future directions of treating solid tumors by targeting neovascularization.

A novel 2-aminobenzimidazole-based compound Jzu 17 exhibits anti-angiogenesis effects by targeting VEGFR-2 signalling

BACKGROUND AND PURPOSE

Recent development in drug discovery have shown benzimidazole to be an important pharmacophore,. Benzimidazole derivatives exhibit broad-spectrum pharmacological properties including anti-microbial, anti-diabetic and anti-tumour activity. However, whether benzimidazole derivatives are effective in suppressing angiogenesis and its underlying mechanisms remain incompletely understood. In this study, we aim to characterize the anti-angiogenic mechanisms of a novel 2-aminobenzimidazole-based compound, Jzu 17, in an effort to develop novel angiogenesis inhibitor.

EXPERIMENTAL APPROACH

Effects of Jzu 17 on endothelial cell proliferation, migration, invasion, and activation of signalling molecules induced by VEGF-A, were analysed by immunoblotting, MTT, BrdU, migration, and invasion assays. We performed tube formation assay, aorta ring sprouting assay, matrigel plug assay, and a mouse model of metastasis to evaluate ex vivo and in vivo anti-angiogenic effects of Jzu 17.

KEY RESULTS

Jzu 17 inhibited VEGF-A-induced cell proliferation, migration, invasion, and endothelial tube formation of HUVECs. Jzu 17 suppressed VEGF-A-induced microvessel sprouting ex vivo and attenuated VEGF-A- or tumour cell-induced neovascularization in vivo. Jzu 17 also reduced B16F10 melanoma lung metastasis. In addition, Jzu 17 inhibited the phosphorylation of VEGFR-2 and its downstream signalling molecules in VEGF-A-stimulated HUVECs. Results from computer modelling further showed that Jzu 17 binds to VEGFR-2 with high affinity.

CONCLUSIONS AND IMPLICATIONS

Jzu 17 may inhibit endothelial remodelling and suppress angiogenesis through targeting VEGF-A-VEGFR-2 signalling. These results also suggest Jzu 17 as a potential lead compound and warrant the clinical development of similar agents in the treatment of cancer and angiogenesis-related diseases.

MicroRNAs in the cornea: Role and implications for treatment of corneal neovascularization

With no safe and efficient approved therapy available for treating corneal neovascularization, the search for alternative and effective treatments is of great importance. Since the discovery of miRNAs as key regulators of gene expression, knowledge of their function in the eye has expanded continuously, facilitated by high throughput genomic tools such as microarrays and RNA sequencing. Recently, reports have emerged implicating miRNAs in pathological and developmental angiogenesis. This has led to the idea of targeting these regulatory molecules as a therapeutic approach for treating corneal neovascularization. With the growing volume of data generated from high throughput tools applied to study corneal neovascularization, we provide here a focused review of the known miRNAs related to corneal neovascularization, while presenting new experimental data and insights for future research and therapy development.

Successful treatment of metastatic colorectal cancer with apatinib: report of two cases and literature review

Apatinib, a novel small molecule tyrosine kinase inhibitor that inhibits vascular endothelial growth factor receptor-2, was approved for metastatic gastric adenocarcinoma in China in Oct 2014. This is the first report on its use for advanced colorectal cancer as a kind of third-line therapy to date. Here we report two Chinese patients who presented with metastatic colorectal cancer who received apatinib 850 mg daily as a third-line therapy. Both the patients achieved favorable benefits in outcomes after the administration of apatinib. Patient 1 benefited 4 months progression-free survival and 11 months overall survival, while patient 2’s progression-free survival was over 10 months. Both the patients presented hand–foot syndrome, and one of them suffered a slight impairment of liver function, mild elevated blood pressure, and proteinuria. But these adverse events were manageable with symptomatic treatment and dose reduction or a short-time drug withdrawal.

Classical VEGF, Notch and Ang signalling in cancer angiogenesis, alternative approaches and future directions (Review)

Angiogenesis is the formation of new vessels starting from pre-existing vasculature. Tumour environment is characterized by 'aberrant angiogenesis', whose main features are tortuous and permeable blood vessels, heterogeneous both in their structure and in efficiency of perfusion and very different from normal vessels. Therapeutic strategies targeting the three pathways chiefly involved in tumour angiogenesis, VEGF, Notch and Ang signalling, have been identified to block the vascular supply to the tumour. However, phenomena of toxicity, development of primary and secondary resistance and hypoxia significantly blunted the effects of anti-angiogenic drugs in several tumour types. Thus, different strategies aimed to overcome these problems are imperative. The focus of the present review was some principal 'alternative' approaches to classic antiangiogenic therapies, including the cyclooxygenase-2 (COX-2) blockade, the use of oligonucleotide complementary to the miRNA to compete with the mRNA target (antimiRs) and the inhibition of matrix metalloproteinases (MMPs). The role of blood soluble VEGFA as a predictive biomarker during antiangiogenic therapy in gastric, ovarian and colorectal cancer was also examined.

Spotlight on ramucirumab in the treatment of nonsmall cell lung cancer: design, development, and clinical activity

The vascular endothelial growth factor (VEGF) and receptor is a therapeutic target because of the importance of this pathway in carcinogenesis. This pathway regulates and promotes angiogenesis as well as increases endothelial cell proliferation, permeability, and cancer survival. Ramucirumab is a new fully human monoclonal antibody that targets the VEGF receptor-2, an important key receptor implicated in angiogenesis. Ramucirumab has been approved for the treatment of second-line advanced or metastatic non-small cell lung cancer (NSCLC) in combination with the chemotherapy agent docetaxel. This was based on the result of the randomized trial REVEL of 1,253 patients with metastatic NSCLC previously treated with a platinum-based combination therapy. The authors observed a significant improvement in overall survival (OS) with an acceptable toxicities profile. In this study, patients were randomized to receive ramucirumab plus docetaxel or placebo with docetaxel. The combination of docetaxel and ramucirumab showed an improved OS (hazard ratio [HR]: 0.86; 95% CI: 0.75, 0.98). Median OS was 10.5 months in the ramucirumab arm versus 9.1 months in the placebo arm. Regarding side effects, the toxicity described on the ramucirumab arm were principally diarrhea, fatigue, and neutropenia. The most common (5%) adverse reactions of grade 3 and 4 in the ramucirumab arm were fatigue, neutropenia, febrile neutropenia, leukopenia, and hypertension. Adding ramucirumab to docetaxel improves QoL of patients, and does not impair symptoms or functioning. There are currently several trials in progress evaluating the effects of ramucirumab in combination with other drugs in patients with advanced NSCLC.

Antagonist antibodies to vascular endothelial growth factor receptor 2 (VEGFR-2) as anti-angiogenic agents

Interaction of numerous signaling pathways in endothelial and mesangial cells results in exquisite control of the process of physiological angiogenesis, with a central role played by vascular endothelial growth factor receptor 2 (VEGFR-2) and its cognate ligands. However, deregulated angiogenesis participates in numerous pathological processes. Excessive activation of VEGFR-2 has been found to mediate tissue-damaging vascular changes as well as the induction of blood vessel expansion to support the growth of solid tumors. Consequently, therapeutic intervention aimed at inhibiting the VEGFR-2 pathway has become a mainstay of treatment in cancer and retinal diseases. In this review, we introduce the concepts of physiological and pathological angiogenesis, the crucial role played by the VEGFR-2 pathway in these processes, and the various inhibitors of its activity that have entered the clinical practice. We primarily focus on the development of ramucirumab, the antagonist monoclonal antibody (mAb) that inhibits VEGFR-2 and has recently been approved for use in patients with gastric, colorectal, and lung cancers. We examine in-depth the pre-clinical studies using DC101, the mAb to mouse VEGFR-2, which provided a conceptual foundation for the role of VEGFR-2 in physiological and pathological angiogenesis. Finally, we discuss further clinical development of ramucirumab and the future of targeting the VEGF pathway for the treatment of cancer.

International Experts Panel Meeting of the Italian Association of Thoracic Oncology on Antiangiogenetic Drugs for Non-Small Cell Lung Cancer: Realities and Hopes

Angiogenesis, one of the hallmarks of cancer, occurs when new blood vessels feed malignant cells, providing oxygen and nutrients, promoting tumor growth, and allowing tumor cells to escape into the circulation, thus leading to metastases. To date, a series of antiangiogenic drugs (either monoclonal antibodies or small molecules) have been approved by regulatory agencies for the treatment of advanced non-small cell lung cancer, and they are currently available for both first- and second-line therapy. The overall benefit of these drugs seems modest (although clearly significant), especially when administered as a single agent, and there is no clear consensus with regard to which patients should be candidates to receive these drugs across the different disease settings. From the biological perspective, angiogenesis represents a difficult and complex process to explore, given the interference with other key pathways and the dynamic evolution during the disease's history. Indeed, this process is complicated by the presence of multiple targets to hit, polymorphisms, hypoxia-dependent modifications, and epigenetics. These difficulties do not allow capture of which specific key pathways can be identified as biomarkers of efficacy so as to maximize to overall benefit of such drugs. An International Experts Panel Meeting was inspired by the absence of clear recommendations to address which patients should receive antiangiogenic drugs in the context of advanced non-small cell lung cancer so as to support decisions for clinical practice on a daily basis and determine priorities for future research. After a literature review and panelists consensus, a series of recommendations were defined to support decisions for the daily clinical practice and to indicate a potential road map for translational research.