Biology subjects

Lawler, S.

Publications and source records attributed to Lawler, S..

3 recordsLinked to original sources

bioRxiv2020

Nucleolin is expressed in human fetal brain development and reactivated in human glial brain tumors regulating angiogenesis and vascular metabolism

Glioblastoma (GBM) is amongst the deadliest human cancers and is characterized by high levels of vascularisation. Angiogenesis is highly dynamic during brain development and almost quiescent in the adult brain, but is reactivated in vascular-dependent CNS pathologies such as brain tumors. Nucleolin (NCL) is a known regulator of cell proliferation and angiogenesis, but its roles on physiological and pathological brain vasculature remain unknown. Here, we studied the expression of Nucleolin in the neurovascular unit (NVU) in human fetal brains and human gliomas in vivo as well as its effects on sprouting angiogenesis and endothelial metabolism in vitro. Nucleolin is highly expressed in endothelial- and perivascular cells during brain development, downregulated in the adult brain, and upregulated in glioma. Moreover, Nucleolin expression in tumor- and blood vessel cells correlated with glioma malignancy in vivo. In culture, siRNA-mediated NCL knockdown reduced human umbilical vein endothelial cell (HUVEC) sprouting angiogenesis, proliferation and filopodia extension, and reduced glucose metabolism. Mechanistically, RNA sequencing of Nucleolin knockdown in HUVECs revealed a putative p53-TIGAR-HK2 regulation of endothelial glycolysis. These findings identify Nucleolin as a neurodevelopmental factor reactivated in glioma that positively regulates sprouting angiogenesis and endothelial metabolism. Our findings have important implications in therapeutic targeting of glioma.

neuroscience↗

bioRxiv2020

Role of neutrophil extracellular traps in regulation of lung cancer invasion and metastasis: Structural Insights from a Computational Model

Lung cancer is one of the leading causes of cancer-related deaths worldwide and is characterized by hijacking immune system for active growth and aggressive metastasis. Neutrophils, which in their original form should establish immune activities to the tumor as a first line of defense, are undermined by tumor cells to promote tumor invasion in several ways. In this study, we investigate the mutual interactions between the tumor cells and the neutrophils that facilitate tumor invasion by developing a mathematical model that involves taxis-reaction-diffusion equations for the critical components in the interaction. These include the densities of tumor and neutrophils, and the concentrations of signaling molecules and structure such as neutrophil extracellular traps (NETs). We apply the mathematical model to a Boyden invasion assay used in the experiments to demonstrate that the tumor-associated neutrophils can enhance tumor cell invasion by secreting the neutrophil elastase. We show that the model can both reproduce the major experimental observation on NET-mediated cancer invasion and make several important predictions to guide future experiments with the goal of the development of new anti-tumor strategies. Moreover, using this model, we investigate the fundamental mechanism of NET-mediated invasion of cancer cells and the impact of internal and external heterogeneity on the migration patterning of tumour cells and their response to different treatment schedules. Author summaryWhen cancer patients are diagnosed with tumours at a primary site, the cancer cells are often found in the blood or already metastasized to the secondary sites in other organs. These metastatic cancer cells are more resistant to major anti-cancer therapies, and lead to the low survival probability. Until recently, the role of neutrophils, specifically tumor-associated neutrophils as a member of complex tumor microenvironment, has been ignored for a long time due to technical difficulties in tumor biology but these neutrophils are emerging as an important player in regulation of tumor invasion and metastasis. The mutual interaction between a tumor and neutrophils from bone marrow or in blood induces the critical transition of the naive form, called the N1 type, to the more aggressive phenotype, called the N2 TANs, which then promotes tumor invasion. In this article, we investigate how stimulated neutrophils with different N1 and N2 landscapes shape the metastatic potential of the lung cancers. Our simulation framework is designed for boyden invasion chamber in experiments and based on a mathematical model that describes how tumor cells interact with neutrophils and N2 TANs can promote tumor cell invasion. We demonstrate that the efficacy of anti-tumor (anti-invasion) drugs depend on this critical communication and N1 [->] N2 landscapes of stimulated neutrophils.

cancer biology↗

bioRxiv2020

BTP-7, a novel peptide for therapeutic targeting of malignant brain tumors

BackgroundTargeted therapies for malignant brain cancer that are currently available have little clinical activity, highlighting an urgent need for the development of novel precision medicines. Brevican (Bcan), a central nervous system (CNS)-specific extracellular matrix protein is upregulated in glioma cells. A brevican isoform lacking glycosylation, dg-Bcan, is a unique glioma marker and thus represents a valuable target for anti-cancer therapy. In this study, we aimed to find a versatile dg-Bcan specific ligand to facilitate glioma targeting. MethodsWe screened a D-peptide library to identify dg-Bcan-Targeting Peptide (BTP) candidates, which were characterized extensively through binding kinetic analyses, cell uptake tests and animal studies. ResultsThe top candidate, BTP-7 binds dg-Bcan with high affinity and specificity, is preferentially internalized by Bcan-expressing glioma cells and can cross the blood-brain barrier in vitro and in mice. Functionalization of camptothecin with BTP-7 led to increased drug delivery to intracranial glioblastoma and cytotoxicity in tumor tissues, as well as prolonged survival in tumor-bearing mice. Conclusiondg-Bcan is an attractive therapeutic target for high-grade gliomas, and BTP-7 represents a promising lead candidate for further development into novel targeted therapeutics. Key pointsO_LIBTP-7 is a high affinity peptide ligand for the dg-Bcan protein and Bcan-expressing cells. C_LIO_LIBTP-7 targets human intracranial GBM xenografts in mice. C_LIO_LIFunctionalization of a toxic anti-cancer drug with BTP-7 enables targeted delivery of the therapeutic to intracranial GBM in mice C_LI Importance of the StudyTargeted therapies for malignant brain cancer that are currently available have little clinical activity, highlighting an urgent need for the development of novel precision medicines that can selectively recognize and kill high-grade glioma tissues. A protein called dg-Bcan is an ideal target because it is present only in the extracellular matrix of high-grade glioma cells and is absent from normal brain tissues. Here, we describe the discovery of a novel dg-Bcan-Targeting Peptide, called BTP-7 that can bind specifically to high-grade glioma cells/tissues, and thus serve as a promising drug delivery vehicle.

bioengineering↗