Upregulation of NAD(P)H:quinone oxidoreductase by radiation potentiates the effect of bioreductive beta-lapachone on cancer cells.

Choi, Eun K,Terai, Kaoru,Ji, In-Mi,Kook, Yeon H,Park, Kyung H,Oh, Eun T,Griffin, Robert J,Lim, Byung U,Kim, Jin-Seok,Lee, Doo S,Boothman, David A,Loren, Melissa,Song, Chang W,Park, Heon Joo Stockton Press 2007 Neoplasia Vol.9 No.8

<P>We found that beta-lapachone (beta-lap), a novel bioreductive drug, caused rapid apoptosis and clonogenic cell death in A549 human lung epithelial cancer cells in vitro in a dose-dependent manner. The clonogenic cell death caused by beta-lap could be significantly inhibited by dicoumarol, an inhibitor of NAD(P)H:quinone oxido-reductase (NQO1), and also by siRNA for NQO1, demonstrating that NQO1-induced bioreduction of beta-lap is an essential step in beta-lap-induced cell death. Irradiation of A549 cells with 4 Gy caused a long-lasting upregulation of NQO1, thereby increasing NQO1-mediated beta-lap-induced cell deaths. Although the direct cause of beta-lap-induced apoptosis is not yet clear, beta-lap treatment reduced the expression of p53 and NF-kappaB, whereas it increased cytochrome C release, caspase-3 activity, and gammaH2AX foci formation. Importantly, beta-lap treatment immediately after irradiation enhanced radiation-induced cell death, indicating that beta-lap sensitizes cancer cells to radiation, in addition to directly killing some of the cells. The growth of A549 tumors induced in immunocompromised mice could be markedly suppressed by local radiation therapy when followed by beta-lap treatment. This is the first study to demonstrate that combined radiotherapy and beta-lap treatment can have a significant effect on human tumor xenografts.</P>

Identification of h-ras-specific motif for the activation of invasive signaling program in human breast epithelial cells.

Yong, Hae-Young,Hwang, Jin-Sun,Son, Hwajin,Park, Hae-In,Oh, Eok-Soo,Kim, Hyun-Hwi,Kim, Do Kyun,Choi, Wahn Soo,Lee, Bong-Jin,Kim, Hyeong-Reh Choi,Moon, Aree Stockton Press 2011 Neoplasia Vol.13 No.2

<P>Increased expression and/or activation of H-Ras are often associated with tumor aggressiveness in breast cancer. Previously, we showed that H-Ras, but not N-Ras, induces MCF10A human breast epithelial cell invasion and migration, whereas both H-Ras and N-Ras induce cell proliferation and phenotypic transformation. In an attempt to determine the sequence requirement directing the divergent phenotype induced by H-Ras and N-Ras with a focus on the induction of human breast cell invasion, we investigated the structural and functional relationships between H-Ras and N-Ras using domain-swap and site-directed mutagenesis approaches. Here, we report that the hypervariable region (HVR), consisting of amino acids 166 to 189 in H-Ras, determines the invasive/migratory signaling program as shown by the exchange of invasive phenotype by swapping HVR sequences between H-Ras and N-Ras. We also demonstrate that the H-Ras-specific additional palmitoylation site at Cys184 is not responsible for the signaling events that distinguish between H-Ras and N-Ras. Importantly, this work identifies the C-terminal HVR, especially the flexible linker domain with two consecutive proline residues Pro173 and Pro174, as a critical domain that contributes to activation of H-Ras and its invasive potential in human breast epithelial cells. The present study sheds light on the structural basis for the Ras isoform-specific invasive program of breast epithelial cells, providing information for the development of agents that specifically target invasion-related H-Ras pathways in human cancer.</P>

Viscosity and wettability of animal mucin solutions and human saliva

Park, M-S,Chung, J-W,Kim, Y-K,Chung, S-C,Kho, H-S Stockton Press 2007 Oral diseases Vol. No.

<P>Objective: </P><P>The purpose of this study was to compare viscosity and wettability between animal mucin solutions and human saliva.</P><P>Materials and Methods: </P><P>Human whole and glandular saliva, porcine gastric mucin, bovine submaxillary mucin, and a mucin-based saliva substitute were used. Viscosity was measured with a cone-and-plate digital viscometer, while wettability on acrylic resin and Co–Cr alloy was determined by the contact angle.</P><P>Results: </P><P>The viscosity of animal mucin solutions was proportional to mucin concentration, with the animal mucin solution of concentration 5.0 mg ml<SUP>−1</SUP> displaying similar viscosity to stimulated whole saliva. A decrease in contact angle was found with increasing animal mucin concentration. For the saliva samples tested, viscosity increased in the following order: stimulated parotid saliva, stimulated whole saliva, unstimulated whole saliva, stimulated submandibular–sublingual saliva. Contact angles of human saliva on the tested solid phases were inversely correlated with viscosity. Contact angles of human saliva on acrylic resin were much lower than those of animal mucin solutions and of those on Co–Cr alloy (<I>P</I> < 0.01).</P><P>Conclusions: </P><P>The effectiveness of animal mucin solutions in terms of their rheological properties was objectively confirmed, indicating a vital role for mucin in proper oral function as well as the development of effective salivary substitutes.</P>

Alteration of BMP-4 and <i>Runx2</i> expression patterns in mouse temporomandibular joint after ovariectomy

Min, H-J,Lee, M-J,Kim, J-Y,Cho, S-W,Park, H-D,Lee, S-I,Kim, H-J,Jung, H-S Stockton Press 2007 Oral diseases Vol. No.

<P>Objective: </P><P>Temporomandibular disorder (TMD) includes a number of clinical conditions involving the masticatory musculature or the temporomandibular joint (TMJ) and associated structures. Previous studies have shown the presence of high-affinity estrogen receptors in the TMJ articular cartilage. The aim of this study was to evaluate the developmental changes in mouse TMJ under estrogen deficiency.</P><P>Materials and methods: </P><P>Four-month-old ovariectomized mice were killed after certain weeks. We examined the significant alterations of the expression patterns of bone morphogenetic protein (BMP)-4, <I>Runx2</I>, and bone sialoprotein (BSP) after ovariectomy.</P><P>Results: </P><P>In the control group, BMP-4, <I>Runx2</I>, and BSP expressions showed no definite difference at any stage. In the ovariectomy group, the intensity of BMP-4 and <I>Runx2</I> expression increased after ovariectomy. BSP immunoreactivity, however, increased slightly at 2 weeks but then decreased gradually.</P><P>Conclusions: </P><P>Estrogen plays important roles in the metabolism and maintenance of TMJ via regulations of signaling molecules such as BMP-4, <I>Runx2</I>, and BSP. Our results suggest that estrogen deficiency is a candidate cause of TMD. This study revealed further osteogenetic properties of estrogen that may be useful in the clinical treatment and prevention of TMD.</P>

Tumor evolution and intratumor heterogeneity of an oropharyngeal squamous cell carcinoma revealed by whole-genome sequencing.

Zhang, Xinyi Cindy,Xu, Chang,Mitchell, Ryan M,Zhang, Bo,Zhao, Derek,Li, Yao,Huang, Xin,Fan, Wenhong,Wang, Hongwei,Lerma, Luisa Angelica,Upton, Melissa P,Hay, Ashley,M?ndez, Eduardo,Zhao, Lue Ping Stockton Press 2013 Neoplasia Vol.15 No.12

<P>Head and neck squamous cell carcinoma (HNSCC) is characterized by significant genomic instability that could lead to clonal diversity. Intratumor clonal heterogeneity has been proposed as a major attribute underlying tumor evolution, progression, and resistance to chemotherapy and radiation. Understanding genetic heterogeneity could lead to treatments specific to resistant and metastatic tumor cells. To characterize the degree of intratumor genetic heterogeneity within a single tumor, we performed whole-genome sequencing on three separate regions of an human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma and two separate regions from one corresponding cervical lymph node metastasis. This approach achieved coverage of approximately 97.9% of the genome across all samples. In total, 5701 somatic point mutations (SPMs) and 4347 small somatic insertions and deletions (indels)were detected in at least one sample. Ninety-two percent of SPMs and 77% of indels were validated in a second set of samples adjacent to the discovery set. All five tumor samples shared 41% of SPMs, 57% of the 1805 genes with SPMs, and 34 of 55 cancer genes. The distribution of SPMs allowed phylogenetic reconstruction of this tumor's evolutionary pathway and showed that the metastatic samples arose as a late event. The degree of intratumor heterogeneity showed that a single biopsy may not represent the entire mutational landscape of HNSCC tumors. This approach may be used to further characterize intratumor heterogeneity in more patients, and their sample-to-sample variations could reveal the evolutionary process of cancer cells, facilitate our understanding of tumorigenesis, and enable the development of novel targeted therapies.</P>

The effect of cortical activation on orthodontic tooth movement

Cho, K-W,Cho, S-W,Oh, C-O,Ryu, Y-K,Ohshima, H,Jung, H-S Stockton Press 2007 Oral Diseases Vol. No.

<P>Objective: </P><P>Cortical activation is one of the procedures to accelerate tooth movement by manipulating the cortical bone. In this study, the effect of cortical activation on orthodontic tooth movement was investigated clinically and histologically in the surrounding bony tissue.</P><P>Materials and methods: </P><P>In the lower and upper jaws of two beagle dogs, cortical activation was applied to the buccal and lingual side of the alveolar bone in the right jaw where 12 holes were made on each cortical plate 4 weeks after the extraction of all the second bicuspids while under deep anesthesia. All third bicuspids on both jaws were forced to move forward by a 150-g force using NiTi coil spring with/without guiding wire. The tooth movement was measured and the animals were killed after tooth movement.</P><P>Results: </P><P>Rapid initial tooth movement was apparent after cortical activation. However, after 6 months of cortical activation, the cell number and cellular activity of the surrounding periodontal tissue were decreased.</P><P>Conclusions: </P><P>This experiment showed that rapid initial tooth movement was apparent following the application of orthodontic force after cortical activation but the cellular activity and fibroblast structure were abnormal in the surrounding periodontal tissue.</P>

Novel <i>ITGB6</i> mutation in autosomal recessive amelogenesis imperfecta

Seymen, F,Lee, K-E,Koruyucu, M,Gencay, K,Bayram, M,Tuna, EB,Lee, ZH,Kim, J-W Stockton Press 2015 Oral diseases Vol.21 No.4

<P><B>Objective</B></P><P>Hereditary defects in tooth enamel formation, amelogenesis imperfecta (AI), can be non-syndromic or syndromic phenotype. Integrins are signaling proteins that mediate cell–cell and cell–extracellular matrix communication, and their involvement in tooth development is well known. The purposes of this study were to identify genetic cause of an AI family and molecular pathogenesis underlying defective enamel formation.</P><P><B>Materials and Methods</B></P><P>We recruited a Turkish family with isolated AI and performed mutational analyses to clarify the underlying molecular genetic etiology.</P><P><B>Results</B></P><P>Autozygosity mapping and exome sequencing identified a novel homozygous <I>ITGB6</I> transversion mutation in exon 4 (c.517G>C, p.Gly173Arg). The glycine at this position in the middle of the <I>β</I>I-domain is conserved among a wide range of vertebrate orthologs and human paralogs. Clinically, the enamel was generally thin and pitted with pigmentation. Thicker enamel was noted at the cervical area of the molars.</P><P><B>Conclusions</B></P><P>In this study, we identified a novel homozygous <I>ITGB6</I> mutation causing isolated AI, and this advances the understanding of normal and pathologic enamel development.</P>

Comparison of the composition of oral mucosal residual saliva with whole saliva

Lee, J-Y,Chung, J-W,Kim, Y-K,Chung, S-C,Kho, H-S Stockton Press 2007 Oral Diseases Vol. No.

<P>Objective: </P><P>Compared with whole saliva, residual saliva comprising the oral mucosal film shows a high protein concentration. The purpose of this study was to compare the composition of residual saliva with unstimulated and stimulated whole saliva in normosalivators.</P><P>Materials and methods: </P><P>The composition of oral mucosal residual saliva in 30 healthy individuals was investigated and compared with that of whole saliva. The concentrations of total protein, secretory immunoglobin A (sIgA), lactoferrin, total carbohydrate, and sialic acid were examined. The activities of peroxidase, lysozyme and <I>&agr;</I>-amylase were determined.</P><P>Results: </P><P>Residual saliva had higher levels of total protein and carbohydrate than whole saliva, with a higher carbohydrate to protein ratio in the residual saliva suggesting that salivary glycoproteins are concentrated on the oral mucosal surface. sIgA, lactoferrin and sialic acid were present as highly concentrated forms in residual saliva. The enzymatic activity of peroxidase in residual saliva was higher than that of whole saliva.</P><P>Conclusions: </P><P>These concentrated carbohydrate and antimicrobials on the oral mucosal surface work for mucosal defence and could be used for targeting sites for the delivery of therapeutic agents.</P>

Characteristics of bifunctional acidic endoglucanase (Cel5B) from Gloeophyllum trabeum.

Kim, Ho Myeong,Lee, Yoon Gyo,Patel, Darshan H,Lee, Kwang Ho,Lee, Dae-Seok,Bae, Hyeun-Jong Published by Stockton Press on behalf of the Socie 2012 Journal of industrial microbiology & biotechnology Vol.39 No.7

<P>The endoglucanase (Cel5B) from the filamentous fungus Gloeophyllum trabeum was cloned and expressed without a signal peptide, and alanine residue 22 converted to glutamine in Pichia pastoris GS115. The DNA sequence of Cel5B had an open reading frame of 1,077 bp, encoding a protein of 359 amino acid residues with a molecular weight of 47 kDa. On the basis of sequence similarity, Cel5B displayed active site residues at Glu-175 and Glu-287. Both residues lost full hydrolytic activity when replaced with alanine through point mutation. The purified recombinant Cel5B showed very high specific activity, about 80- to 1,000-fold and 13- to 70-fold in comparison with other endoglucanases and cellobiohydrolase, on carboxymethylcellulose and filter paper, respectively, at pH 3.5 and 55C. Cel5B displayed bifunctional characteristics under acidic conditions. The kinetic properties of the enzyme determined using a Lineweaver-Burk plot indicated that Cel5B is a catalytically efficient cellulolytic enzyme. These results suggest that Cel5B has high bifunctional endo- and exoglucanase activity under acidic conditions and is a good candidate for bioconversion of lignocellulose.</P>

Efficient gamma-aminobutyric acid bioconversion by employing synthetic complex between glutamate decarboxylase and glutamate/GABA antiporter in engineered Escherichia coli.

Le Vo, Tam Dinh,Ko, Ji-seun,Park, Si Jae,Lee, Seung Hwan,Hong, Soon Ho Published by Stockton Press on behalf of the Socie 2013 Journal of industrial microbiology & biotechnology Vol.40 No.8

<P>Gamma-aminobutyric acid (GABA) is a precursor of one of the most promising heat-resistant biopolymers, Nylon-4, and can be produced by the decarboxylation of monosodium glutamate (MSG). In this study, a synthetic protein complex was applied to improve the GABA conversion in engineered Escherichia coli. Complexes were constructed by assembling a single protein-protein interaction domain SH3 to the glutamate decarboxylase (GadA and GadB) and attaching a cognate peptide ligand to the glutamate/GABA antiporter (GadC) at the N-terminus, C-terminus, and the 233rd amino acid residue. When GadA and GadC were co-overexpressed via the C-terminus complex, a GABA concentration of 5.65 g/l was obtained from 10 g/l MSG, which corresponds to a GABA yield of 93 %. A significant increase of the GABA productivity was also observed where the GABA productivity increased 2.5-fold in the early culture period due to the introduction of the synthetic protein complex. The GABA pathway efficiency and GABA productivity were enhanced by the introduction of the complex between Gad and glutamate/GABA antiporter.</P>