Assay Development and Screening for the Identification of Ganglioside GM3 Synthase Inhibitors

Discovery of Novel Binders to Sterol Regulatory Element-Binding Protein-1 by High-Throughput Screening

Sterol regulatory element-binding protein-1 (SREBP-1) is a transcription factor that regulates the expression of genes related to fatty acid biosynthesis. Its high expression and activation in obesity and associated metabolic diseases make it a potential therapeutic target. However, the role of SREBP-1 in the development and exacerbation of these diseases remains unclear, partly because of the impossibility of inhibiting its function because of the lack of specific inhibitors. Here, we aimed to identify small-molecule compounds that directly bind to SREBP-1 using the recombinant N-terminal region of SREBP-1a, which is required for its transcriptional activity. A high-throughput screening campaign was conducted using a thermal shift assay and surface plasmon resonance assay to evaluate the compound affinity and specificity, which resulted in the identification of two compounds. Future analysis of their structure-activity relationships may lead to the development of specific SREBP-1 inhibitors, thereby potentially validating SREBP-1 as a therapeutic target for obesity and resultant atherosclerotic diseases.

Fragment-Based Discovery of Novel VE-PTP Inhibitors Using Orthogonal Biophysical Techniques

Tyrosine phosphorylation is an essential post-translational modification that regulates various biological events and is implicated in many diseases including cancer and atherosclerosis. Vascular endothelial protein tyrosine phosphatase (VE-PTP), which plays an important role in vascular homeostasis and angiogenesis, is therefore an attractive drug target for these diseases. However, there are still no drugs targeting PTP including VE-PTP. In this paper, we report the discovery of a novel VE-PTP inhibitor, Cpd-2, by fragment-based screening combining various biophysical techniques. Cpd-2 is the first VE-PTP inhibitor with a weakly acidic structure and high selectivity, unlike known strongly acidic inhibitors. We believe that this compound represents a new possibility for the development of bioavailable VE-PTP inhibitors.

How sphingolipids affect T cells in the resolution of inflammation

The concept of proper resolution of inflammation rather than counteracting it, gained a lot of attention in the past few years. Re-assembly of tissue and cell homeostasis as well as establishment of adaptive immunity after inflammatory processes are the key events of resolution. Neutrophiles and macrophages are well described as promotors of resolution, but the role of T cells is poorly reviewed. It is also broadly known that sphingolipids and their imbalance influence membrane fluidity and cell signalling pathways resulting in inflammation associated diseases like inflammatory bowel disease (IBD), atherosclerosis or diabetes. In this review we highlight the role of sphingolipids in T cells in the context of resolution of inflammation to create an insight into new possible therapeutical approaches.

Aberrant Sialylation in Cancer: Biomarker and Potential Target for Therapeutic Intervention?

Simple Summary

Sialylation is a post-translational modification that consists in the addition of sialic acid to growing glycan chains on glycoproteins and glycolipids. Aberrant sialylation is an established hallmark of several types of cancer, including breast, ovarian, pancreatic, prostate, colorectal and lung cancers, melanoma and hepatocellular carcinoma. Hypersialylation can be the effect of increased activity of sialyltransferases and results in an excess of negatively charged sialic acid on the surface of cancer cells. Sialic acid accumulation contributes to tumor progression by several paths, including stimulation of tumor invasion and migration, and enhancing immune evasion and tumor cell survival. In this review we explore the mechanisms by which sialyltransferases promote cancer progression. In addition, we provide insights into the possible use of sialyltransferases as biomarkers for cancer and summarize findings on the development of sialyltransferase inhibitors as potential anti-cancer treatments.

Abstract

Sialylation is an integral part of cellular function, governing many biological processes including cellular recognition, adhesion, molecular trafficking, signal transduction and endocytosis. Sialylation is controlled by the levels and the activities of sialyltransferases on glycoproteins and lipids. Altered gene expression of these enzymes in cancer yields to cancer-specific alterations of glycoprotein sialylation. Mounting evidence indicate that hypersialylation is closely associated with cancer progression and metastatic spread, and can be of prognostic significance in human cancer. Aberrant sialylation is not only a result of cancer, but also a driver of malignant phenotype, directly impacting key processes such as tumor cell dissociation and invasion, cell-cell and cell-matrix interactions, angiogenesis, resistance to apoptosis, and evasion of immune destruction. In this review we provide insights on the impact of sialylation in tumor progression, and outline the possible application of sialyltransferases as cancer biomarkers. We also summarize the most promising findings on the development of sialyltransferase inhibitors as potential anti-cancer treatments.

Siglec and anti-Siglec therapies

Siglecs (sialic acid-binding immunoglobulin-like lectins) are a family of receptors that bind sialic acids in specific linkages on glycoproteins and glycolipids. Siglecs play roles in immune signalling and exhibit cell-type specific expression and endocytic properties. Recent studies suggest that Siglecs are likely to function as immune checkpoints that regulate responses in cancers and inflammatory diseases. In this review, we discuss strategies to target the Siglec-sialic acid axis in human diseases, particularly cancer, and the possibility of exploiting them for therapeutic intervention.