Shih Yin Chen

Proteomic identification of salivary transferrin as a biomarker for early detection of oral cancer.

Oral cancer has a low five-year survival rate. Early detection of oral cancer could reduce the mortality and morbidity associated with this disease. Saliva, which can be sampled non-invasively and is less complex than blood, is a good potential source of oral cancer biomarkers. Proteomic analysis of saliva from oral cancer patients and control subjects was performed to identify salivary biomarkers of early stage oral cancer in humans. The protein profile of pooled salivary samples from patients with oral squamous cell carcinoma (OSCC) or OSCC-free control subjects was analyzed using two-dimensional gel electrophoresis (2DE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analyses. Potential biomarkers were verified by Western blotting and ELISA assays. Transferrin levels were elevated in the saliva of OSCC patients as determined using 2DE followed by MALDI-TOF MS and confirmed by MALDI-TOF/TOF MS, Western blotting and ELISA. The increase in salivary transferrin levels in OSCC patients strongly correlated with the size and stage of the tumor. The area under the receiver-operating characteristics curves showed that salivary transferrin-based ELISA was highly specific, sensitive and accurate for the early detection of oral cancer. We have identified salivary transferrin as a biomarker for the detection of early stage oral cancer. This finding provides a promising basis for the development of a non-invasive diagnostic test for early stage oral cancer.

Genome-wide association study of diabetic retinopathy in a Taiwanese population.

PURPOSE Diabetic retinopathy (DR) is a microvascular complication of diabetes with a complex multifactorial pathogenesis. The aim of this study was to identify the susceptibility genes that increase the risk of DR in type 2 diabetes (T2D) and to further elucidate the underlying mechanism of DR pathogenesis. DESIGN A case-control study. PARTICIPANTS We included 749 unrelated individuals with T2D (174 with DR and 575 without DR) and 100 nondiabetic controls. METHODS We conducted a genome-wide association study using Illumina HumanHap550-Duo BeadChips. MAIN OUTCOME MEASURES Compared with the genotypic distribution of single nucleotide polymorphisms (SNPs) between subjects with DR and without DR. RESULTS Using statistical models, we selected a total of 12 SNPs with P-values <1 × 10(-6) that were associated with DR. After controlling for diabetes duration and hemoglobin A(1C), 9 of the 12 SNPs located on 5 chromosomal regions were found to be associated with DR. Five loci not previously associated with DR susceptibility were identified in and around the following genes: MYSM1 (Myb-like, SWIRM, and MPN domains 1) located on chromosome 1p (odds ratio [OR], 1.50; 95% confidence interval [CI], 1.03-2.20); PLXDC2 (plexin domain-containing 2) located on the chromosome 10p (OR, 1.67; 95% CI, 1.06-2.65); ARHGAP22 (Rho GTPase-activating protein 22) located on chromosome 10q (OR, 1.65; 95% CI, 1.05-2.60); and HS6ST3 (heparan sulfate 6-O-sulfotransferase 3) located on chromosome 13q (OR, 2.33; 95% CI, 1.13-4.77). The SNPs rs13163610 and rs17376456 located in the unknown gene on chromosome 5q were also associated with DR (OR, 3.63; 95% CI, 1.38-9.58). CONCLUSIONS We identified a genetic association for susceptibility to DR in 5 novel chromosomal regions and PLXDC2 and ARHGAP22, the latter 2 of which are genes implicated in endothelial cell angiogenesis and increased capillary permeability. These findings suggest unsuspected pathways in the pathogenesis of DR.

Induced Pluripotent Stem (iPS) Cell Research Overview

Stem cells are capable of self-renewal and differentiation into a wide range of cell types with multiple clinical therapeutic applications. The two most important issues associated with embryonic stem (ES) cells are immune rejection and medical ethics. In 2006, induced pluripotent (iPS) cells were generated from somatic cells via the introduction of four transcriptional factors: OCT4, SOX2, c-MYC, and KLF4. Researchers found that iPS cell morphology, proliferation, surface antigens, gene expression, telomerase activity, and the epigenetic status of pluripotent cell-specific genes were similar to the same characteristics in ES cells. iPS cells are capable of overcoming hurdles associated with ES cells due to their generation from mature somatic cells (e.g., fibroblasts). For this reason, iPS cells are considered an increasingly important cell therapy technology. iPS cell production entails the use of retroviruses, lentiviruses, adenoviruses, plasmid transfections, transposons, or recombinant proteins. In this article we discuss the advantages and limitations of each strategy and address issues associated with clinical trials, including the potential for liver tumor formation and low generation efficiency.

Salivary zinc finger protein 510 peptide as a novel biomarker for detection of oral squamous cell carcinoma in early stages

BACKGROUND Oral squamous cell carcinoma (OSCC) is one of the most frequent malignancies worldwide. Early diagnosis can mean adequate treatment and increase survival. METHODS This study uses ClinProt technique to identify salivary biomarkers for early diagnosis of OSCC. A total of 77 salivary samples from both OSCC patients (n=47) and healthy donors (n=30) were analyzed with MALDI-TOF MS technology. RESULTS Salivary peptides from OSCC patients were separated, using C8-functionalized magnetic beads. Three signals (2918.57 Da, 5592.64 Da, and 4372.66 Da) distinguished OSCC patients from controls. Among them, unique peptide 2918.57 Da, identified as a 24-mer peptide of zinc finger protein 510 (ZNF510), was found in 0% of saliva from healthy individuals, versus 25.0% and 60% from OSCC patients with T1+T2 and T3+T4 stages, respectively (P<0.001). ELISA analysis with rabbit anti-ZNF510 peptide sera shows a starkly higher 24-mer ZNF510 peptide level in saliva from OSCC patients than that in controls (P<0.001). Also, in immunohistochemical analysis of oral tissues, a significantly higher level of ZNF510 was observed in OSCC tissues than in the OSCC free control tissues. Analysis of areas under receiver-operating characteristic (ROC) curves in OSCC early (T1+T2) and late stages (T3+T4) shows greater than 0.95. CONCLUSIONS Identifying 24-mer ZNF510 peptide as OSCC-related salivary biomarkers via proteomic approach proved useful in adjunct diagnosis for early detection rather than specific diagnosis marker for progression of OSCC patients.

Glycine N-methyltransferase affects the metabolism of aflatoxin B1 and blocks its carcinogenic effect.

Previously, we reported that glycine N-methyltransferase (GNMT) knockout mice develop chronic hepatitis and hepatocellular carcinoma (HCC) spontaneously. For this study we used a phosphoenolpyruvate carboxykinase promoter to establish a GNMT transgenic (TG) mouse model. Animals were intraperitoneally inoculated with aflatoxin B(1) (AFB(1)) and monitored for 11 months, during which neither male nor female GNMT-TG mice developed HCC. In contrast, 4 of 6 (67%) male wild-type mice developed HCC. Immunofluorescent antibody test showed that GNMT was translocated into nuclei after AFB(1) treatment. Competitive enzyme immunoassays indicated that after AFB(1) treatment, the AFB(1)-DNA adducts formed in stable clones expressing GNMT reduced 51.4% compared to the vector control clones. Experiments using recombinant adenoviruses carrying GNMT cDNA (Ad-GNMT) further demonstrated that the GNMT-related inhibition of AFB(1)-DNA adducts formation is dose-dependent. HPLC analysis of the metabolites of AFB(1) in the cultural supernatants of cells exposed to AFB(1) showed that the AFM(1) level in the GNMT group was significantly higher than the control group, indicating the presence of GNMT can enhance the detoxification pathway of AFB(1). Cytotoxicity assay showed that the GNMT group had higher survival rate than the control group after they were treated with AFB(1). Automated docking experiments showed that AFB(1) binds to the S-adenosylmethionine binding domain of GNMT. Affinity sensor assay demonstrated that the dissociation constant for GNMT-AFB(1) interaction is 44.9 microM. Therefore, GNMT is a tumor suppressor for HCC and it exerts protective effects in hepatocytes via direct interaction with AFB(1), resulting in reduced AFB(1)-DNA adducts formation and cell death.

An overview of concepts for cancer stem cells.

For many years, cancer research has focused on the adult stem cells present in malignant tumors. It is believed that current cancer treatments sometimes fail because they do not target these cells. According to classic models of carcinogenesis, these events can occur in any cell. In contrast, the cancer stem cell (CSC) hypothesis states that the preferential targets of oncogenic transformation are tissue stem cells or early progenitor cells that have acquired the potential for self-renewal. These tumor-initiating cells, or CSCs, in turn, are characterized by their ability to undergo self-renewal, a process that drives tumorigenesis and differentiation, which contributes to the cellular heterogeneity of tumors. Herein, we discuss the definitions and properties of CSCs in the major human cancers.

Proteomics-based identification of haptoglobin as a novel plasma biomarker in oral squamous cell carcinoma

BACKGROUND Identification of tumor biomarkers to assist early diagnosis and monitoring of disease progression may potentially decrease the mortality and morbidity associated with oral cancer. METHODS A mouse model with oral squamous cell carcinoma (OSCC) induced by 4-nitroquinoline 1-oxide (4-NQO)/arecoline in drinking water was established to discover stage-associated biomarkers. A proteomics approach, immunoblot and immunohistochemical analysis were used to validate the expressed biomarkers in mice with OSCC. Human plasma samples were also collected and candidate biomarkers were evaluated using enzyme-linked immunosorbent assay. RESULTS Proteomic profiling of mouse plasma samples indicated that haptoglobin and apolipoprotein A1 precursor were up-regulated in the mice with OSCC. Immunoblotting of plasma samples and immunohistochemical analysis of oral tissues showed a significantly higher level of haptoglobin in the OSCC mice than in the control mice. The expression of haptoglobin in human plasma samples from 52 patients with OSCC indicated a strong correlation between the increasing levels of haptoglobin and the clinical stages of OSCC (P<0.01). CONCLUSIONS These results suggest that haptoglobin has a great potential as a sensitive plasma biomarker for early detection of patients with OSCC.

Stem cell applications in regenerative medicine for neurological disorders

Stem cells are capable of self-renewal and differentiation into a wide range of cell types with multiple clinical and therapeutic applications. Stem cells are providing hope for many diseases that currently lack effective therapeutic methods, including stroke, amyotrophic lateral sclerosis, Alzheimers disease, and Parkinsons disease. Embryonic stem (ES) cells were originally targeted for differentiation into functional dopamine neurons for cell therapy. Today, induced pluripotent stem (iPS) cells are being tested for such purposes as generating functional dopamine neurons and treating a rat model of Parkinsons disease. In addition, neural stem cell and mesenchymal stem cells are also being used in neurodegenerative disorder therapies for stroke and Parkinsons disease. Although stem cell therapy is still in its infancy, it will likely become a powerful tool for many diseases that currently do not have effective therapeutic approaches. In this article, we discuss current research on the potential application of neural stem cells, mesenchymal stem cells, ES cells, and iPS cells to neurodegenerative disorders.

Autophagy and its link to type II diabetes mellitus

Autophagy, a double-edged sword for cell survival, is the research object on 2016 Nobel Prize in Physiology or Medicine. Autophagy is a molecular mechanism for maintaining cellular physiology and promoting survival. Defects in autophagy lead to the etiology of many diseases, including diabetes mellitus (DM), cancer, neurodegeneration, infection disease and aging. DM is a metabolic and chronic disorder and has a higher prevalence in the world as well as in Taiwan. The character of diabetes mellitus is hyperglycemia resulting from defects in insulin secretion, insulin action, or both. Type 2 diabetes mellitus (T2DM) is characterized by insulin resistance and failure of producing insulin on pancreatic beta cells. In T2DM, autophagy is not only providing nutrients to maintain cellular energy during fasting, but also removes damaged organelles, lipids and miss-folded proteins. In addition, autophagy plays an important role in pancreatic beta cell dysfunction and insulin resistance. In this review, we summarize the roles of autophagy in T2DM.

Sambucus williamsii induced embryonic stem cells differentiated into neurons

The pluripotent stem cells, including embryonic stem cells (ESCs), are capable of self-renewal and differentiation into any cell type, thus making them the focus of many clinical application studies. However, the efficiency of ESCs differentiated into neurons needs to improve. In this study, we tried to increase efficiently to a neural fate in the presence of various transitional Chinese medicines through a three-step differentiation strategy. From extracts of 10 transitional Chinese medicine candidates, we determined that Sambucus williamsii (SW) extract triggers the up-regulation of Nestin and Tuj1 (neuron cells markers) gene expression levels. After determining the different concentrations of SW extract, the number of neurons in the 200 μg/ml SW extract group was higher than the control, 50, 100, and 400 μg/ml SW extract groups. In addition, the number of neurons in the 200 μg/ml SW extract group was higher and higher after each time passage (three times). We also detected the Oct4, Sox2 (stem cells markers), Tuj1, and Nestin genes expression levels by RT-PCR. In the differentiated process, Oct4 and Sox2 genes decreased while the Tuj1 and Nestin genes expression levels increased. In summary, we demonstrated that SW could induce pluripotent stem cells differentiated into neurons. Thus, SW might become a powerful material for neurons–differentiating strategies.