Byung-Ju Park

Comparative proteomic analysis for the insoluble fractions of colorectal cancer patients

We used label-free quantitative proteomics with the insoluble fractions from colorectal cancer (CRC) patients to gain further insight into the utility of profiling altered protein expression as a potential biomarker for cancer. The insoluble fractions were prepared from paired tumor/normal biopsies from 13 patients diagnosed with CRC (stages I to IV). Fifty-six proteins identified in data pooled from the 13 cases were differentially expressed between the tumor and adjacent normal tissue. The connections between these proteins are involved in reciprocal networks related to tumorigenesis, cancer incidence based on genetic disorder, and skeletal and muscular disorders. To assess their potential utility as biomarkers, the relative expression levels of the proteins were validated using personal proteomics and a heat map to compare five individual CRC samples with five normal tissue samples. Further validation of a panel of proteins (KRT5, JUP, TUBB, and COL6A1) using western blotting confirmed the differential expression. These proteins gave specific network information for CRC, and yielded a panel of novel markers and potential targets for treatment. It is anticipated that the experimental approach described here will increase our understanding of the membrane environment in CRC, which may provide direction for making diagnoses and prognoses through molecular biomarker targeting.

The role of peroxiredoxin V in (-)-epigallocatechin 3-gallate-induced multiple myeloma cell death.

(-)-Epigallocatechin 3-gallate (EGCG) is a potent antioxidant polyphenol in green tea that acts as an anticancer agent via both direct and indirect pathways. Although the relationship between EGCGs anticancer effects and its antioxidant activity is not fully understood, it is known that EGCG stimulates production of reactive oxygen species (ROS), which induce oxidative stress leading to cell death. In IM9 multiple myeloma cells, EGCG acted in a dose- and time-dependent manner to induce apoptotic cell death. Among the antioxidant enzymes expressed in IM9 cells, levels of peroxiredoxin V (PrdxV) were selectively and significantly reduced by EGCG. Moreover, the ROS scavenger NAC completely inhibited EGCG-induced apoptosis and PrdxV reduction, while overexpression of PrdxV, but not a Prdx(VC48S) mutant, protected IM9 cells from EGCG-induced apoptosis. EGCG-induced reductions in cell viability and PrdxV levels were also observed in primary CD138+ multiple myeloma cells from patients. These results suggest that PrdxV is a key target via which EGCG mediates its anticancer effects.

In‐depth analysis of cysteine oxidation by the RBC proteome: Advantage of peroxiredoxin II knockout mice

Peroxiredoxin II (Prdx II, a typical 2‐Cys Prdx) has been originally isolated from erythrocytes, and its structure and peroxidase activity have been adequately studied. Mice lacking Prdx II proteins had heinz bodies in their peripheral blood, and morphologically abnormal cells were detected in the dense red blood cell (RBC) fractions, which contained markedly higher levels of reactive oxygen species (ROS). In this study, a labeling experiment with the thiol‐modifying reagent biotinylated iodoacetamide (BIAM) in Prdx II−/− mice revealed that a variety of RBC proteins were highly oxidized. To identify oxidation‐sensitive proteins in Prdx II−/− mice, we performed RBC comparative proteome analysis in membrane and cytosolic fractions by nano‐UPLC‐MSE shotgun proteomics. We found oxidation‐sensitive 54 proteins from 61 peptides containing cysteine oxidation, and analyzed comparative expression pattern in healthy RBCs of Prdx II+/+ mice, healthy RBCs of Prdx II−/− mice, and abnormal RBCs of Prdx II−/− mice. These proteins belonged to cellular functions related with RBC lifespan maintain, such as cytoskeleton, stress‐induced proteins, metabolic enzymes, signal transduction, and transporters. Furthermore, protein networks among identified oxidation‐sensitive proteins were analyzed to associate with various diseases. Consequently, we expected that RBC proteome might provide clues to understand redox‐imbalanced diseases.

Studies on Nutritional Analysis and Antioxidant activity of Oriental Medicines with Bloodstream Improvement

This study investigated applicable values and developments of 5 different kinds of oriental medicine materials as functional supplements or medicinal uses, known to improve blood circulation by means of analyzing nutritional compositions and antioxidant activities. Among general nutritional compositions, protein, iron and copper contents in Polygini Multiflori Radix (20.28%, 132.22 μg/100 g, 26.54 μg/100 g), Angelica Gigantis Radix (16.54%, 98.20 μg/100 g, 32.15 μg/100 g) and Paeoniae Radix(18.67%, 62.10 μg/100 g, 20.32 μg/100 g) were significantly higher than other materials. Angelica Gigantis Radix had the highest of total polyphenols and flavonoid contents, Polygini Multiflori Radix (middle), Paeoniae Radix (the lowest). Antioxidant activities by using DPPH radicals removal showed the highest in Polygini Multiflori Radix, Angelica Gigantis Radix (middle), Paeoniae Radix (the lowest). This study tried to use integrated approaches, including Western and Oriental medicine to improve blood circulation and to set up base to develop products originated from natural compositions.

INFLUENCE OF THE LABIAL SURFACE IRREGULARITY ON THE MEASUREMENT OF THE TOOTH COLOR BY SPECTROMETER

The most scientific and reliable method for deciding the tooth color is the instrumental measurement. However, such color measuring instrument shows the difference of the measuring value according to the diversified measuring condition. This study was conducted to evaluate what effect of the labial surface irregularity of the tooth to the result of the color measured by spectrometer. 11 models of the teeth were made by injecting the A2 shade Luxatemp Automix Plus (DMG, Germany) into the impression acquired from 11 adults. Standard disk samples (15 mm diameter, 7 mm thickness) were made with same material. CIE value was measured at the incisal, central, and gingival area of the central incisor, lateral incisor, canine and first premolar using Specbos 2100 (JETI, Germany) spectrometer. Color difference was calculated between labial surface and standard samples. Among all models of the teeth, value showed the reducing tendency as they go toward the gingival area, but value showed the increasing tendency. Color difference between model teeth and standard samples showed the most difference at the incisal area, but the gingival area showed the least difference. And the canine showed the least color difference from the comparison of standard sample, and the central incisor showed the highest difference (p value showed notable differences depending more on the measured areas than on the type of the teeth.