Neurovascular EGFL7 regulates adult neurogenesis in the subventricular zone and thereby affects olfactory perception
Adult neural stem cells reside in a specialized niche in the subventricular zone (SVZ). Throughout life they give rise to adult-born neurons in the olfactory bulb (OB), thus contributing to neural plasticity and pattern discrimination. Here, we show that the neurovascular protein EGFL7 is secreted by endothelial cells and neural stem cells (NSCs) of the SVZ to shape the vascular stem-cell niche. Loss of EGFL7 causes an accumulation of activated NSCs, which display enhanced activity and re-entry into the cell cycle. EGFL7 pushes activated NSCs towards quiescence and neuronal progeny towards differentiation. This is achieved by promoting Dll4-induced Notch signalling at the blood vessel-stem …
Differential expression of the tumor suppressor A-kinase anchor protein 12 in human diffuse and pilocytic astrocytomas is regulated by promoter methylation
The scaffold protein A-kinase anchor protein 12 (AKAP12) exerts tumor suppressor activity and is downregulated in several tumor entities. We characterized AKAP12 expression and regulation in astrocytomas, including pilocytic and diffusely infiltrating astrocytomas. We examined 194 human gliomas and 23 normal brain white matter samples by immunohistochemistry or immunoblotting for AKAP12 expression. We further performed quantitative methylation analysis of the AKAP12 promoter by MassARRAY® of normal brain, World Health Organization (WHO) grade I to IV astrocytomas, and glioma cell lines. Our results show that AKAP12 is expressed in a perivascular distribution in normal CNS, strongly upregula…
EGFL7 ligates αvβ3 integrin to enhance vessel formation
Angiogenesis, defined as blood vessel formation from a preexisting vasculature, is governed by multiple signal cascades including integrin receptors, in particular integrin αVβ3. Here we identify the endothelial cell (EC)-secreted factor epidermal growth factor-like protein 7 (EGFL7) as a novel specific ligand of integrin αVβ3, thus providing mechanistic insight into its proangiogenic actions in vitro and in vivo. Specifically, EGFL7 attaches to the extracellular matrix and by its interaction with integrin αVβ3 increases the motility of EC, which allows EC to move on a sticky underground during vessel remodeling. We provide evidence that the deregulation of EGFL7 in zebrafish embryos leads …
EGFL7 enhances surface expression of integrin α5β1 to promote angiogenesis in malignant brain tumors
Abstract Glioblastoma (GBM) is a typically lethal type of brain tumor with a median survival of 15 months postdiagnosis. This negative prognosis prompted the exploration of alternative treatment options. In particular, the reliance of GBM on angiogenesis triggered the development of anti‐VEGF (vascular endothelial growth factor) blocking antibodies such as bevacizumab. Although its application in human GBM only increased progression‐free periods but did not improve overall survival, physicians and researchers still utilize this treatment option due to the lack of adequate alternatives. In an attempt to improve the efficacy of anti‐VEGF treatment, we explored the role of the egfl7 gene in ma…
Increased tumor vascularization is associated with the amount of immune competent PD‑1 positive cells in testicular germ cell tumors
Testicular germ cell cancer in a metastatic state is curable with a cisplatin‑based first line chemotherapy. However, 10‑15% of these patients are resistant to first line chemotherapy and are thus left with only palliative options. Immunotherapies and inhibition of angiogenesis used in multiple types of cancer; however, the molecular context of angiogenesis and immune checkpoints in the development and progression of testicular cancers is still unknown. Therefore, the present study performed tissue micro array based analysis of 84 patients with immunohistochemistry of programmed cell death protein 1 (PD‑1), programmed cell death ligand 1 (PD‑L1) and vascular endothelial growth factor recept…
P08.76 Anti-EGFL7 treatment as an add-on for glioma therapy
Glioblastoma multiforme (GBM) is one the most common and malignant forms of brain tumors. The median survival time of patients diagnosed with primary GBM is around 15 months. In spite of multimodal treatments GBMs remain essentially incurable. Therefore, alternative treatments targeting previously unexplored aspects of GBMs are required. However, the molecular mechanisms underlying the formation of brain tumors have only partially been defined. Especially Notch, a conserved developmental pathway, is promising in terms of GBM formation, as components of this signaling cascade are aberrantly expressed in gliomas. Studies reported that the inhibition of Notch decreased glioma cell proliferatio…
CD133 expression is associated with small round blue cell tumour morphology in human central nervous system neoplasms
Schittenhelm J, Simon P, Harter P N, Zachskorn C, Schlaszus H, Rottger F, Winkels M, Weller M, Meyermann R & Mittelbronn M (2011) Histopathology58, 739–749 CD133 expression is associated with small round blue cell tumour morphology in human central nervous system neoplasms Aims: CD133 is considered to be a marker for brain tumour-initiating cells. However, most data on CD133 are derived from animal or in-vitro studies. The aim of this study was to characterize CD133 expression, and the distribution and morphological features of CD133+ cells, in primary and secondary human central nervous system (CNS) neoplasms. Methods and results: Tumours were analysed by real-time reverse transcription …