Chien-Hsing Lee

Epidermal growth factor receptor regulates β-catenin location, stability, and transcriptional activity in oral cancer

BackgroundMany cancerous cells accumulate β-catenin in the nucleus. We examined the role of epidermal growth factor receptor (EGFR) signaling in the accumulation of β-catenin in the nuclei of oral cancer cells.ResultsWe used two strains of cultured oral cancer cells, one with reduced EGFR expression (OECM1 cells) and one with elevated EGFR expression (SAS cells), and measured downstream effects, such as phosphorylation of β-catenin and GSK-3β, association of β-catenin with E-cadherin, and target gene regulation. We also studied the expression of EGFR, β-catenin, and cyclin D1 in 112 samples of oral cancer by immunostaining. Activation of EGFR signaling increased the amount of β-catenin in the nucleus and decreased the amount in the membranes. EGF treatment increased phosphorylation of β-catenin (tyrosine) and GSK-3β(Ser-(9), resulting in a loss of β-catenin association with E-cadherin. TOP-FLASH and FOP-FLASH reporter assays demonstrated that the EGFR signal regulates β-catenin transcriptional activity and mediates cyclin D1 expression. Chromatin immunoprecipitation experiments indicated that the EGFR signal affects chromatin architecture at the regulatory element of cyclin D1, and that the CBP, HDAC1, and Suv39h1 histone/chromatin remodeling complex is involved in this process. Immunostaining showed a significant association between EGFR expression and aberrant accumulation of β-catenin in oral cancer.ConclusionsEGFR signaling regulates β-catenin localization and stability, target gene expression, and tumor progression in oral cancer. Moreover, our data suggest that aberrant accumulation of β-catenin under EGFR activation is a malignancy marker of oral cancer.

Plasma protein growth arrest-specific 6 levels are associated with altered glucose tolerance, inflammation, and endothelial dysfunction.

OBJECTIVE Plasma protein growth arrest–specific 6 (Gas6) is important to the inflammatory process and is involved in the development of diabetic renal and vascular complications. We set out to determine whether plasma Gas6 levels are associated with altered glucose tolerance, insulin sensitivity, inflammation, and endothelial dysfunction. RESEARCH DESIGN AND METHODS A total of 278 adults, including 96 with normal glucose tolerance (NGT), 82 with impaired glucose tolerance (IGT), and 100 with type 2 diabetes were recruited. Plasma Gas6 concentration and biochemical, proinflammatory, and endothelial variables were determined. Insulin sensitivity was examined by homeostasis model assessment. RESULTS Plasma Gas6 concentration was significantly lower among patients with type 2 diabetes compared with subjects with NGT (P < 0.001). The plasma Gas6 value was inversely correlated with fasting glucose, tumor necrosis factor (TNF)-α, interleukin (IL)-6, and vascular cell adhesion molecule (VCAM)-1. In multivariate logistic regression analysis, after adjustment for established diabetes risk factors, higher plasma Gas6 concentrations were significantly associated with a decreased risk of type 2 diabetes. Moreover, the association became slightly stronger after further adjustment for TNF-α, IL-6, high-sensitive C-reactive protein, E-selectin, intercellular adhesion molecule-1, and VCAM-1. CONCLUSIONS Plasma Gas6 is associated with altered glucose tolerance, inflammation, and endothelial dysfunction. It also may represent a novel independent risk factor of type 2 diabetes and a potential surrogate marker of inflammation and endothelial dysfunction.

Circulating Growth Arrest-Specific 6 Protein Is Associated With Adiposity, Systemic Inflammation, and Insulin Resistance Among Overweight and Obese Adolescents

CONTEXT Growth arrest-specific 6 (Gas6) is a vitamin K-dependent protein secreted by immune cells, endothelial cells, vascular smooth muscle cells, and adipocytes. Preclinical studies indicate that Gas6 and its receptors of the TAM (Tyro-3, Axl, Mer) family may be involved in the pathogenesis of obesity and its complications, including systemic inflammation and insulin resistance. Until now, little has been known about the clinical significance of the Gas6/TAM system in childhood obesity. OBJECTIVES This study aimed to determine whether circulating Gas6 and soluble Axl (sAxl) levels are associated with adiposity, inflammation, and insulin resistance status among Taiwanese adolescents. METHODS Cross-sectional analyses using the data from the Taipei Children Heart Study-III were performed. A total of 832 adolescents (average age, 13.3 years) were included; they were divided into 3 groups: lean, overweight, and obese. Circulating Gas6 and sAxl levels, adiposity, inflammatory markers, and insulin resistance status were examined. RESULTS Levels of circulating Gas6 and sAxl were significantly higher in overweight and obese adolescents than in the lean group (both P < .05). Circulating Gas6 levels were significantly positively correlated with body mass index Z-score (P = .045), waist circumference (P < .001), waist to hip circumference ratio (P < .001), body fat mass (P = .02), serum high-sensitivity C-reactive protein (P = .005), and tumor necrosis factor-α levels (P = .039) among overweight and obese adolescents. The correlations remained significant after adjusting for age, gender, Tanner stage, smoking status, and drinking status. In addition, every 1 ng/mL increase in circulating Gas6 concentration corresponded to a 15% to 19% increase in the risk of developing insulin resistance among overweight and obese adolescents. CONCLUSIONS Circulating Gas6 levels are strongly associated with adiposity, inflammation, and insulin resistance status among overweight and obese adolescents. The potential role of the Gas6/TAM system in the initiation of childhood obesity and obesity-associated complications deserves further attention.

Soluble Form of Receptor for Advanced Glycation End Products Is Associated with Obesity and Metabolic Syndrome in Adolescents

The aim of this cross-sectional study was to investigate the relationship between soluble form of receptor for advanced glycation end products (sRAGE), obesity, and metabolic syndrome (MetS) in adolescents. A total of 522 male and 561 female adolescents were enrolled into the final analyses. Anthropometric parameters, blood pressure, blood biochemistry, fasting insulin, and plasma sRAGE levels were measured. In males, sRAGE was significantly and inversely correlated with waist circumference (WC), body mass index (BMI), systolic blood pressure, triglyceride (TG), low density lipoprotein cholesterol (LDL-C), and homeostasis model assessment-insulin resistance (HOMA-IR). Only WC and BMI were significantly and inversely correlated with sRAGE in females. Using linear regression analysis adjusting for age and gender, significant association was found between sRAGE and WC, BMI, TG, LDL-C, and HOMA-IR in adolescents of either gender (P < 0.05). This association was abolished when further adjusting BMI. In addition, sRAGE was significantly and inversely correlated with the increasing number of components of MetS in males (P for trend = 0.006) but not in females (P for trend = 0.422). In conclusion, plasma sRAGE is associated with obesity and MetS among adolescents. BMI may be the most important determinant of sRAGE levels in adolescents.

Inhibition of hypoxia inducible factor-1α attenuates abdominal aortic aneurysm progression through the down-regulation of matrix metalloproteinases.

Hypoxia inducible factor-1α (HIF-1α) pathway is associated with many vascular diseases, including atherosclerosis, arterial aneurysms, pulmonary hypertension and chronic venous diseases. Significant HIF-1α expression could be found at the rupture edge at human abdominal aortic aneurysm (AAA) tissues. While our initial in vitro experiments had shown that deferoxamine (DFO) could attenuate angiotensin II (AngII) induced endothelial activations; we unexpectedly found that DFO augmented the severity of AngII-induced AAA, at least partly through increased accumulation of HIF-1α. The findings promoted us to test whether aneurysmal prone factors could up-regulate the expression of MMP-2 and MMP-9 through aberrantly increased HIF-1α and promote AAA development. AngII induced AAA in hyperlipidemic mice model was used. DFO, as a prolyl hydroxylase inhibitor, stabilized HIF-1α and augmented MMPs activities. Aneurysmal-prone factors induced HIF-1α can cause overexpression of MMP-2 and MMP-9 and promote aneurysmal progression. Pharmacological HIF-1α inhibitors, digoxin and 2-ME could ameliorate AngII induced AAA in vivo. HIF-1α is pivotal for the development of AAA. Our study provides a rationale for using HIF-1α inhibitors as an adjunctive medical therapy in addition to current cardiovascular risk-reducing regimens.

Polarization of tumor-associated macrophages and Gas6/Axl signaling in oral squamous cell carcinoma

BACKGROUND This study investigated the potential involvement of Axl signaling in polarization of tumor-associated macrophages (TAMs) in oral squamous cell carcinoma (OSCC). METHODS Condition medium (CM) from OSCC cells (OEC-M1 and YD38) were collected and their effects on macrophage (THP-1) polarization were examined. Modulation of Axl, PI3/Akt, and NF-κB were performed to investigate their potential involvement in TAM polarization. Expression of pAxl and CD206 were analyzed by immunohistochemistry in OSCC tissues. RESULTS THP-1 polarized to M2 phenotype with increasing expression of interleukins, vascular endothelial growth factor, matrix metalloproteinase and CD206 upon treatment with CM of OSCC. Activated Axl signaling in OSCC enhanced M2 induction ability. Suppression of Axl signaling and inhibition of PI3/Akt and NF-κB diminished M2 induction. pAxl expression was significantly associated with distribution of CD206 positive cells in OSCC tissues. CONCLUSION Axl signaling of OSCC involved in polarizing TAMs toward M2 phenotype. Induction of M2 phenotype macrophage polarization by OSCC cells might involve the Axl/PI3/Akt/NF-κB pathway.

Platelet count can predict metabolic syndrome in older women

Abstract Platelet count (PC) has been found to be related to the metabolic syndrome (MetS). However, the role of PC on MetS remained unclear. In order to evaluate the relationship between PC and MetS components cross-sectionally and determine the optimal cutoff PCs for predicting the subsequent risk of MetS development with sex specificity, two stages included cross-sectional (stage 1) and prospective (stage 2) cohort study were conducted. Stage 1 involved 10 579 subjects aged ≥60 years, of which 7718 subjects advanced to stage 2 with a mean 3.8 year follow-up were enrolled. The MetS components and PC were determined. The PC cutoffs for higher chances of developing MetS in stage 1 were calculated using receiver operating characteristic (ROC) curve analyses. In stage 2, non-MetS subjects were classified into high-PC (HPC) and low-PC (LPC) groups according to the cutoff values from stage 1. We examined the difference of future MetS incidence and calculated the odds ratio (OR) between these two groups. In stage 1, multiple regression showed that age and triglyceride (both sexes) and waist circumstance and high-density lipoprotein cholesterol (only women) were independently correlated with PC. There was significant difference in the area under the ROC curve (AUC) only of HPC women, which exceeded the standard curve (AUC = 0.542, p < 0.001), with a cutoff PC of 223 × 103/μl. HPC women had an OR of 1.287 (95% confidence interval: 1.135–1.461) of developing MetS after 3.8 years. The Kaplan–Meier curve demonstrated a higher incidence of MetS development in HPC women. In conclusion, our results suggest that PC was associated with MetS with sex effects. Most of the MetS components were independent factors for increasing PC, and the risk for subsequent development of MetS was noted when PC >223 × 103/μl in elderly women.

Associations between genetic variants and the severity of metabolic syndrome in subjects with type 2 diabetes

Metabolic syndrome (MetS) includes obesity, dyslipidemia, elevated blood pressure, and dysglycemia. Subjects with type 2 diabetes (T2D) exhibit features of MetS. The etiology of MetS is complex, involving both environmental and genetic factors. In this study, we examined the role of specific candidate genetic variants on the severity of MetS in T2D subjects. A total of 240 T2D subjects aged 35-64 years were recruited. Waist circumstance, plasma triglycerides, high-density lipoprotein cholesterol, fasting plasma glucose, and blood pressure were measured to define MetS. Subjects were divided into 4 groups according to MetS components. Target genes involved in fibrotic and inflammatory processes, insulin and diabetes, cell growth and proliferation, and hypertension were genotyped. A total of 13 genes and 103 single-nucleotide polymorphisms (SNPs) were analyzed to evaluate their genetic association with MetS severity in T2D subjects. Univariate ordinal logistic regression using a dominant model (homozygous for the major allele vs carriers of the minor allele) revealed 6 SNP markers within 4 genes with genotypes associated with MetS risk. For the SNP genotypes of rs362551 (SNAP25), rs3818569 (RXRG), rs1479355, rs1570070 (IGF2R), and rs916829 (ABCC8), heterozygotes showed a lower risk of MetS compared with the reference group. In addition, the CC genotype was comparable to the TT genotype for rs3777411. There was no gender-specific effect. In conclusion, our results suggest that among the Han Chinese population, several SNPs increase the risk of severe MetS in T2D subjects. Further study in a large population should be conducted.

Plasma Concentrations Predict Aortic Expression of Growth-Arrest-Specific Protein 6 in Patients Undergoing Coronary Artery Bypass Grafting

Aims The tyrosine kinase receptor Axl is expressed in the vasculature, and growth arrest-specific protein 6 (Gas6) is its ligand. Plasma Gas6 levels have been shown to be associated with endothelial dysfunction markers and cardiovascular events. We set out to determine the plasma Gas6 levels in patients undergoing coronary artery bypass grafting (CABG) and investigate the expression of Gas6 and Axl in the aorta. Methods and Results Immunoassays were used to investigate plasma Gas6 levels in CABG patients (n = 19) and control subjects (n = 20). The expression of Gas6 and Axl in the injured aorta were examined by reverse transcription-polymerase chain reactions, real-time reverse transcription-polymerase chain reactions, western blotting, and immunohistochemical staining. Plasma Gas6 levels were significantly lower in CABG patients than in matched control subjects. In CABG patients, plasma Gas6 levels were negatively correlated with fasting glucose, E-selectin, and vascular cell adhesion molecule-1 levels. The levels predicted the operative mortality rate and were positively correlated with plasma soluble Axl (sAxl) levels and Gas6 expression in the aorta. Moreover, Gas6 expression was positively correlated with Axl expression in the aorta. Conclusion We concluded that plasma Gas6 is associated with fasting glucose, endothelial dysfunction markers, sAxl values, and vascular Gas6 expression in CABG patients, and it predicts the operative mortality of these patients. These findings suggest that the Gas6/Axl system is crucial in vascular biology.

An Elevated Glycemic Gap is Associated with Adverse Outcomes in Diabetic Patients with Acute Myocardial Infarction

Acute hyperglycemia is a frequent finding in patients presenting to the emergency department (ED) with acute myocardial infarction (AMI). The prognostic role of hyperglycemia in diabetic patients with AMI remains controversial. We retrospectively reviewed patients’ medical records to obtain demographic data, clinical presentation, major adverse cardiac events (MACEs), several clinical scores and laboratory data, including the plasma glucose level at initial presentation and HbA1c levels. The glycemic gap, which represents changes in serum glucose levels during the index event, was calculated from the glucose level upon ED admission minus the HbA1c-derived average glucose (ADAG). We enrolled 331 patients after the review of medical records. An elevated glycemic gap between admission serum glucose levels and ADAG were associated with an increased risk of mortality in patients. The glycemic gap showed superior discriminative power regarding the development of MACEs when compared with the admission glucose level. The calculation of the glycemic gap may increase the discriminative powers of established clinical scoring systems in diabetic patients presenting to the ED with AMI. In conclusion, the glycemic gap could be used as an adjunct parameter to assess the severity and prognosis of diabetic patients presenting with AMI. However, the usefulness of the glycemic gap should be further explored in prospective longitudinal studies.