Publications by authors named "Siew Cheng Wong"

Large numbers of neutrophils infiltrate tumors and comprise a notable component of the inflammatory tumor microenvironment. While it is established that tumor cells exhibit the Warburg effect for energy production, the contribution of the neutrophil metabolic state to tumorigenesis is unknown. Here, we investigated whether neutrophil infiltration and metabolic status promotes tumor progression in an orthotopic mouse model of pancreatic ductal adenocarcinoma (PDAC).

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Inflammation in the tumor microenvironment has been shown to promote disease progression in pancreatic ductal adenocarcinoma (PDAC); however, the role of macrophage metabolism in promoting inflammation is unclear. Using an orthotopic mouse model of PDAC, we demonstrate that macrophages from tumor-bearing mice exhibit elevated glycolysis. Macrophage-specific deletion of Glucose Transporter 1 (GLUT1) significantly reduced tumor burden, which was accompanied by increased Natural Killer and CD8+ T cell activity and suppression of the NLRP3-IL1β inflammasome axis.

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Sepsis is a potentially fatal condition triggered by systemic inflammatory response to infection. Due to the heightened immune reactivity and multi-organ pathology, treatment options are limited and several clinical trials have not produced the desired outcome, hence the interest in the discovery of novel therapeutic strategies. The polyphenol resveratrol (RSV) has shown promise against several pathological states, including acute and chronic inflammation.

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Vitamin D deficiency is a major public health problem worldwide, linked to several chronic diseases including cardiovascular diseases. While immunomodulatory effects of vitamin D on monocytes have been reported in cardiovascular and metabolic diseases, there is limited understanding on monocyte phenotype in healthy individuals with suboptimal vitamin D levels and without any clinical diseases. In this work, we performed label-free, microfluidic isolation of monocytes, and characterized their functional phenotype using flow cytometry and in vitro vascular models in healthy subjects with (n = 7) and without vitamin D deficiency (n = 16).

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Background And Aims: Lipid-rich foam cell macrophages drive atherosclerosis via several mechanisms, including inflammation, lipid uptake, lipid deposition and plaque vulnerability. The atheroma environment shapes macrophage function and phenotype; anti-inflammatory macrophages improve plaque stability while pro-inflammatory macrophages promote rupture. Current evidence suggests a variety of macrophage phenotypes occur in atherosclerotic plaques with local lipids, cytokines, oxidised phospholipids and pathogenic stimuli altering their phenotype.

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Macrophages are abundant in the tumor microenvironment (TME), serving as accomplices to cancer cells for their invasion. Studies have explored the biochemical mechanisms that drive pro-tumor macrophage functions; however the role of TME interstitial flow (IF) is often disregarded. Therefore, we developed a three-dimensional microfluidic-based model with tumor cells and macrophages to study how IF affects macrophage migration and its potential contribution to cancer invasion.

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Biomedical implant failure due to the host's response remains a challenging problem. In particular, the formation of the fibrous capsule is a common barrier for the normal function of implants. Currently, there is mounting evidence indicating that the polarization state of macrophages plays an important role in effecting the foreign body reaction (FBR).

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Human primary monocytes are heterogeneous in terms of phenotype and function, but are sub-divided only based on CD16 and CD14 expression. CD16 expression distinguishes a subset of monocytes with highly pro-inflammatory properties from non-CD16 expressing "classical" monocytes. CD14 expression further subdivides the CD16 monocytes into non-classical CD14 and intermediate CD14 subsets.

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Recent years have seen a renaissance in the research linking inflammation and cancer with immune cells playing a central role in smouldering inflammation in the tumor microenvironment. Diverse immune cell types infiltrate the tumor microenvironment, and the dynamic tumor-immune cell interplay gives rise to a rich milieu of cytokines and growth factors. Fundamentally, this intricate cross-talk creates the conducive condition for tumor cell proliferation, survival and metastasis.

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The role of programmed cell death protein-1 (PD-1)/programmed cell death ligand 1 (PD-L1) in triple negative breast cancer (TNBC) remains to be fully understood. In this study, we investigated the role of PD-1 as a prognostic marker for TNBC in an Asian cohort (n = 269). Samples from patients with TNBC were labeled with antibodies against PD-L1 and PD-1, and subjected to NanoString assays to measure the expression of immune-related genes.

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Background: Emergence of drug-resistant cancer phenotypes is a challenge for anti-cancer therapy. Cancer stem cells are identified as one of the ways by which chemoresistance develops.

Method: We investigated the anti-inflammatory combinatorial treatment (DA) of doxorubicin and aspirin using a preclinical microfluidic model on cancer cell lines and patient-derived circulating tumour cell clusters.

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Immune cells are one of the most versatile cell types, as they can tailor their metabolic activity according to their required function. In response to diverse environmental cues, immune cells undergo metabolic reprogramming to support their differentiation, proliferation and pro-inflammatory effector functions. To meet a dramatic surge in energetic demand, immune cells rewire their metabolism to utilize aerobic glycolysis.

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Monocytes and platelets play key roles in atherosclerosis and thrombosis, and circulating monocyte-platelet aggregates (MPA) in blood have been widely proposed as surrogate biomarkers for cardiovascular risk stratification and monitoring antiplatelet therapies. However, conventional MPA characterization is based on whole-blood fixation and flow cytometry analysis which adversely affect cell viability and detection accuracy due to significant leukocyte and platelet contaminations. Herein, we introduce a rapid and label-free microfluidic approach for complete size-based fractionation of peripheral blood mononuclear cells (PBMCs) into monocytes, lymphocytes, and platelets.

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Circulating leukocytes comprise of approximately 1% of all blood cells and efficient enrichment of these cells from whole blood is critical for understanding cellular heterogeneity and biological significance in health and diseases. In this work, we report a novel microfluidic strategy for rapid (< 1 h) label-free leukocyte sorting and impedance-based profiling to determine cell activation in type 2 diabetes mellitus (T2DM) using whole blood. Leukocytes were first size-fractionated into different subtypes (neutrophils, monocytes, lymphocytes) using an inertial spiral sorter prior to single-cell impedance measurement in a microfluidic device with coplanar electrode design.

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Monocytes are able to undergo homotypic fusion to produce different types of multinucleated giant cells, such as Langhans giant cells in response to infection or foreign body giant cells in response to implanted biomaterials. Monocyte fusion is highly coordinated and complex, with various soluble, intracellular, and cell-surface components mediating different stages of the process. Tetraspanins, such as CD9, CD63, and CD81, are known to be involved in cell:cell fusion and have been suggested to play a role in regulating homotypic monocyte fusion.

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Chalcones present in edible plants possess anti-cancer and anti-inflammatory properties, with the Michael acceptor moiety reported to be responsible for their biological activities. In this study, two novel dihydrotriazine-chalcone compounds previously identified to exert anti-proliferative effects through dual-targeting of dihydrofolate reductase (DHFR) and thioredoxin reductase (TrxR), were evaluated for their anti-invasive and anti-inflammatory abilities. At non-lethal concentrations, the compounds suppressed in vitro migration of MDA-MB-231 breast carcinoma cells, which was correlated with a dose-dependent downregulation of phorbol 12-myristate 13-acetate (PMA)-induced matrix metalloproteinase-9 (MMP-9) expression and secretion.

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In the hepatitis B virus (HBV)-related hepatocellular carcinoma tumor microenvironment (TME), monocytes reportedly impede natural T cell functions PD-L1/PD-1 signaling. However, it remains unclear if T cell receptor-redirected T cells (TCR T cells) are similarly inhibited. Hence, we developed a 3D intrahepatic TME microfluidic model to investigate the immunosuppressive potential of monocytes toward HBV-specific TCR T cells and the role of PD-L1/PD-1 signaling.

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Neutrophils are specialized innate cells that require constant replenishment from proliferative bone marrow (BM) precursors as a result of their short half-life. Although it is established that neutrophils are derived from the granulocyte-macrophage progenitor (GMP), the differentiation pathways from GMP to functional mature neutrophils are poorly defined. Using mass cytometry (CyTOF) and cell-cycle-based analysis, we identified three neutrophil subsets within the BM: a committed proliferative neutrophil precursor (preNeu) which differentiates into non-proliferating immature neutrophils and mature neutrophils.

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Human primary monocytes comprise a heterogeneous population that can be classified into three subsets based on CD14 and CD16 expression: classical (CD14/CD16), intermediate (CD14/CD16), and non-classical (CD14/CD16). The non-classical monocytes are the most pro-inflammatory in response to TLR stimulation in vitro, yet they express a remarkably high basal level of miR-146a, a microRNA known to negatively regulate the TLR pathway. This concurrence of a pro-inflammatory status and a high miR-146a level has been associated with cellular senescence in other cell types.

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Multiplex immunofluorescence (mIF) allows simultaneous antibody-based detection and quantification of the expression of up to six markers, plus a nuclear counterstain, on a single tissue section. Recent studies have shown the potential for mIF to advance our understanding of complex disease processes, including cancer. It is important that the technique be standardised and validated to facilitate its transition into clinical use.

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Atherosclerosis, a chronic inflammatory disorder characterized by endothelial dysfunction and blood vessel narrowing, is the leading cause of cardiovascular diseases including heart attack and stroke. Herein, we present a novel tunable microfluidic atherosclerosis model to study vascular inflammation and leukocyte-endothelial interactions in 3D vessel stenosis. Flow and shear stress profiles were characterized in pneumatic-controlled stenosis conditions (0%, 50% and 80% constriction) using fluid simulation and experimental beads perfusion.

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Purpose: The role of Forkhead Box Protein 3 (Foxp3) expressing regulatory T cells (Tregs) in breast cancer remains unclear. We examined the abundance and localisation of total T cells, B cells and Tregs within samples from triple-negative breast cancers (TNBCs) and asked whether these parameters were associated with clinicopathological features of the cancer or clinical outcomes.

Methods: Samples from TNBCs diagnosed between 2003 and 2010 in Singapore were divided into "high" and "low" intra-tumoural or stromal groups, based on whether they had higher or lower than median densities of specific tumour-infiltrating lymphocyte populations (CD3 total T cells, Foxp3CD3 Tregs, or CD20 B cells) in the intra-tumoural space or stroma.

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Monocytes play a central role in regulating inflammation in response to infection or injury, and during auto-inflammatory diseases. Human blood contains classical, intermediate and non-classical monocyte subsets that each express characteristic patterns of cell surface CD16 and CD14; each subset also has specific functional properties, but the mechanisms underlying many of their distinctive features are undefined. Of particular interest is how monocyte subsets regulate secretion of the apical pro-inflammatory cytokine IL-1β, which is central to the initiation of immune responses but is also implicated in the pathology of various auto-immune/auto-inflammatory conditions.

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