Project description:ObjectivePathological angiogenesis is a hallmark of various diseases characterized by local hypoxia and inflammation. These disorders can be treated with inhibitors of angiogenesis, but current compounds display a variety of side effects and lose efficacy over time. This makes the identification of novel signaling pathways and pharmacological targets involved in angiogenesis a top priority. Approach and Results: Here, we show that inactivation of FAAH (fatty acid amide hydrolase), the enzyme responsible for degradation of the endocannabinoid anandamide, strongly impairs angiogenesis in vitro and in vivo. Both, the pharmacological FAAH inhibitor URB597 and anandamide induce downregulation of gene sets for cell cycle progression and DNA replication in endothelial cells. This is underscored by cell biological experiments, in which both compounds inhibit proliferation and migration and evoke cell cycle exit of endothelial cells. This prominent antiangiogenic effect is also of pathophysiological relevance in vivo, as laser-induced choroidal neovascularization in the eye of FAAH-/- mice is strongly reduced.ConclusionsThus, elevation of endogenous anandamide levels by FAAH inhibition represents a novel antiangiogenic mechanism.
Project description:The heat-shock protein 90 (HSP90) is a promising target in cancer therapy, but its inhibitors' clinical trial failures are partly due to a compensatory heat-shock response (HSR) mediated by heat-shock factor 1 (HSF1). We previously showed that wildtype p53 reduces HSR by repressing HSF1 via a p21-CDK4/6-MAPK-HSF1 axis. Here, we explore if simultaneous p53 activation or cell cycle inhibition can disrupt the HSF1-HSR axis and enhance HSP90 inhibitors' efficiency. mRNA sequencing was performed on HCT116 cells treated for 24 hours with DMSO, 50 nM Ganetespib, 1 µM RG-7388, or their combination. We found that the p53 activator Idasanutlin suppresses HSF1-HSR activity in HSP90 inhibitor-based therapies, synergistically reducing cell viability and accelerating cell death in p53-proficient colorectal cancer (CRC) cells and organoids. Combination therapy upregulates p53 pathways, apoptosis, and inflammation. In a CRC mouse model, dual HSF1-HSP90 inhibition represses tumor growth and alters immune cell composition. CDK4/6 inhibition under HSP90 inhibition mimics HSR repression in p53-proficient CRC cells. In p53-deficient CRC cells and p53-mutated organoids, combined HSP90 and CDK4/6 inhibition suppresses HSF1-HSR and reduces cancer growth, offering a p53-independent strategy for CRC treatment. In conclusion, we present new options to improve HSP90-based therapies for enhanced CRC treatment.
Project description:Background & Aims: Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer deaths in the United States. Tyrosine sulfation, catalyzed by the tyrosylprotein sulfotransferase 2 (TPST2), is a post-translational modification essential for protein-protein interactions and cellular functions. SLC35B2 is a key transporter that transports the universal sulfate donor 3’-phosphoadenosine 5’-phosphosulfate (PAPS) into the Golgi apparatus where the protein sulfation occurs. The goal of this study is to determine whether and how SLC35B2-TPST2 axis of tyrosine sulfation plays a role in PDAC. Methods: Gene expression was analyzed in PDAC patients and mice. Human PDAC MIA PaCa-2 and PANC-1 cells were used for in vitro studies. TPST2 deficient MIA PaCa-2 cells were generated to assess xenograft tumor growth in vivo. Mouse PDAC cells derived from the KrasLSL-G12D/+;Tp53L/+;Pdx1-Cre (KPC) mice were used to generate Tpst2 KO KPC cells to evaluate tumor growth and metastasis in vivo. Results: High expressions of SLC35B2 and TPST2 were correlated with poor PDAC patient survival. Knockdown of SLC35B2 or TPST2, or pharmacological inhibition of sulfation inhibited PDAC cell proliferation and migration in vitro. TPST2 deficient MIA PaCa-2 cells exhibited inhibited xenograft tumor growth. Orthotopic inoculation of Tpst2 KO KPC cells in mice showed inhibition of primary tumor growth, local invasion, and metastasis. Mechanistically, the integrin ITGB4 was found to be a novel substrate of TPST2. Inhibition of sulfation destabilizes ITGB4 protein, which may have accounted for the suppression of metastasis. Conclusions: Targeting the SLC35B2-TPST2 axis of tyrosine sulfation may represent a novel approach for therapeutic intervention of PDAC.
Project description:Heparan sulfate (HS) glycans attached to the apical surface of vascular endothelial cells (ECs) play an important role in regulating endothelial permeability and ligand recognition by cell-surface receptors. Shedding of HS from the EC surface increases vascular leakage and is associated with vascular diseases. Recently, heparanase 2 (Hpa2) was described as a novel regulatory molecule that controls HS shedding. However, its role in regulating HS physiology in the vascular endothelium is largely unknown. Here, we characterize the role of endogenous Hpa2 in the vertebrate vascular system using zebrafish as our primary research model. We detected Hpa2 expression in hepatic tissue and localized the protein in blood vessels. Hpa2 loss-of-function (LOF) larvae exhibited increased vascular permeability, occasional hypersprouting, and altered EC and extracellular matrix (ECM) morphology. Hpa2-LOF also reduced HS levels and caused changes in the endothelial transcriptome characterized by dysregulated genes involved in ECM-receptor interaction and signal transduction regulation. Recombinant Hpa2 rescued the Hpa2-LOF phenotype in zebrafish. Hpa2 competes with fibroblast growth factor 2 (FGF2) and vascular endothelial growth factor A165 (VEGFA165) for binding on the EC surface and consequently reduces the cellular response these factors elicit. Pharmacological inhibition of these pathways alleviated the Hpa2-LOF phenotype in zebrafish. We conclude that Hpa2 is a circulating molecule that maintains vascular integrity by regulating HS-dependent processes on the EC surface. These results may translate into novel strategies applying recombinant Hpa2 to treat microvascular diseases.
Project description:Age-induced decline in osteogenic potential of bone marrow mesenchymal stem cells (BMSCs) potentiates osteoporosis and increases risk for bone fractures. Despite epidemiology studies reporting concurrent development of vascular- and bone diseases in the elderly, the underlying mechanisms for the vascular-bone cross-talk in aging are largely unknown. In this study, we show that accelerated endothelial aging deteriorates bone tissue through paracrine repression of Wnt-driven-axis in BMSCs. Here, we utilize physiologically aged mice in conjunction with our transgenic endothelial progeria mouse model (Hutchinson-Gilford progeria syndrome; HGPS) that displays hallmarks of an aged bone marrow vascular niche. We find bone defects associated with diminished BMSC osteogenic differentiation that implicate the existence of angiocrine factors with long-term inhibitory effects. microRNA-transcriptomics of HGPS-patient plasma combined with aged-vascular niche analyses in progeria mice reveal abundant secretion of Wnt-repressive microRNA-31-5p. Moreover, we show that inhibition of microRNA-31-5p as well as selective Wnt-activator CHIR99021 boost the osteogenic potential of BMSCs through de-repression and activation of the Wnt-signalling, respectively. Our results demonstrate that the vascular niche significantly contributes to osteogenesis defects in aging and pave ground for microRNA-based therapies of bone loss in elderly.