Induction of podoplanin by transforming growth factor-β in human fibrosarcoma

AbstractPodoplanin/aggrus is increased in tumors and its expression was associated with tumor malignancy. Podoplanin on cancer cells serves as a platelet-aggregating factor, which is associated with the metastatic potential. However, regulators of podoplanin remain to be determined. Transforming growth factor-β (TGF-β) regulates many physiological events, including tumorigenesis. Here, we found that TGF-β induced podoplanin in human fibrosarcoma HT1080 cells and enhanced the platelet-aggregating-ability of HT1080. TGF-β type I receptor inhibitor (SB431542) and short hairpin RNAs for Smad4 inhibited the podoplanin induction by TGF-β. These results suggest that TGF-β is a physiological regulator of podoplanin in tumor cells

Platelets Strongly Induce Hepatocyte Proliferation with IGF-1 and HGF In Vitro

Background. It is well known that platelets have athrombotic effect. However, platelets play an importantrole not only in hemostasis but also in woundhealing and tissue regeneration. Platelets have beenreported to accumulate in the liver and promote liverregeneration after an extended hepatectomy, but themechanism is unclear. The present study was designedto clarify the mechanism by which plateletshave a direct proliferative effect on hepatocytes invitro.Materials and methods. Hepatocytes obtained frommale BALB/c mice by collagenase digestion and immortalizedhepatocytes (TLR2) were used. To elucidatethe mechanism of the proliferative effect of platelets,DNA synthesis of hepatocytes was measuredunder various conditions and the related cellular signalswere analyzed. Chromatographic analysis wasalso performed to clarify which elements of plateletshave mitogenic activity.Results. DNA synthesis significantly increased in thehepatocytes cultured with platelets (P < 0.001). However,when the platelets and hepatocytes were separated,the platelets did not have a proliferative effect.Whole disrupted platelets, the supernatant fraction,and fresh isolated platelets had a similar proliferativeeffect, while the membrane fraction did not. After theaddition of platelets, both Akt and extracellularsignal-regulated kinases ERK1/2 were activated, butextracellular signal-regulated kinase STAT3 was not activated. Some mitogenic fractions were obtainedfrom the platelet extracts by gel exclusion chromatography;the fractions were rich in hepatocyte growthfactor and IGF-1.Conclusions. Direct contact between platelets andhepatocytes was necessary for the proliferative effect.The direct contact initiated signal transduction involvedin growth factor activation. Hepatocyte growthfactor, vascular endothelial growth factor, and insulin-like growth factor-1, rather than platelet-derivedgrowth factor, mainly contributed to hepatocyteproliferation

Postnatal lethality and chondrodysplasia in mice lacking both chondroitin sulfate N-acetylgalactosaminyltransferase-1 and -2

Chondroitin sulfate (CS) is a sulfated glycosaminoglycan (GAG) chain. In cartilage, CS plays important roles as the main component of the extracellular matrix (ECM), existing as side chains of the major cartilage proteoglycan, aggrecan. Six glycosyltransferases are known to coordinately synthesize the backbone structure of CS; however, their in vivo synthetic mechanism remains unknown. Previous studies have suggested that two glycosyltransferases, Csgalnact1 (t1) and Csgalnact2 (t2), are critical for initiation of CS synthesis in vitro. Indeed, t1 single knockout mice (t1 KO) exhibit slight dwarfism and a reduction in CS content in cartilage compared with wild-type (WT) mice. To reveal the synergetic roles of t1 and t2 in CS synthesis in vivo, we generated systemic single and double knockout (DKO) mice and cartilage-specific t1 and t2 double knockout (Col2-DKO) mice. DKO mice exhibited postnatal lethality, whereas t2 KO mice showed normal size and skeletal development. Col2-DKO mice survived to adulthood and showed severe dwarfism compared with t1 KO mice. Histological analysis of epiphyseal cartilage from Col2-DKO mice revealed disrupted endochondral ossification, characterized by drastic GAG reduction in the ECM. Moreover, DKO cartilage had reduced chondrocyte proliferation and an increased number of apoptotic chondrocytes compared with WT cartilage. Conversely, primary chondrocyte cultures from Col2-DKO knee cartilage had the same proliferation rate as WT chondrocytes and low GAG expression levels, indicating that the chondrocytes themselves had an intact proliferative ability. Quantitative RT-PCR analysis of E18.5 cartilage showed that the expression levels of Col2a1 and Ptch1 transcripts tended to decrease in DKO compared with those in WT mice. The CS content in DKO cartilage was decreased compared with that in t1 KO cartilage but was not completely absent. These results suggest that aberrant ECM caused by CS reduction disrupted endochondral ossification. Overall, we propose that both t1 and t2 are necessary for CS synthesis and normal chondrocyte differentiation but are not sufficient for all CS synthesis in cartilage

Symbol Nomenclature for Graphical Representations of Glycans

ISSN:0959-665

Enhancement of metastatic ability by ectopic expression of ST6GalNAcI on a gastric cancer cell line in a mouse model

ST6GalNAcI is a sialyltransferase responsible for the synthesis of sialyl Tn (sTn) antigen which is expressed in a variety of adenocarcinomas including gastric cancer especially in advanced cases, but the roles of ST6GalNAcI and sTn in cancer progression are largely unknown. We generated sTn-expressing human gastric cancer cells by ectopic expression of ST6GalNAcI to evaluate metastatic ability of these cells and prognostic effect of ST6GalNAcI and sTn in a mouse model, and identified sTn carrier proteins to gain insight into the function of ST6GalNAcI and sTn in gastric cancer progression. A green fluorescent protein-tagged human gastric cancer cell line was transfected with ST6GalNAcI to produce sTn-expressing cells, which were transplanted into nude mice. STn-positive gastric cancer cells showed higher intraperitoneal metastatic ability in comparison with sTn-negative control, resulting in shortened survival time of the mice, which was mitigated by anti-sTn antibody administration. Then, sTn-carrying proteins were immunoprecipitated from culture supernatants and lysates of these cells, and identified MUC1 and CD44 as major sTn carriers. It was confirmed that MUC1 carries sTn also in human advanced gastric cancer tissues. Identification of sTn carrier proteins will help understand mechanisms of metastatic phenotype acquisition of gastric cancer cells by ST6GalNAcI and sTn

BioHackathon series in 2011 and 2012: penetration of ontology and linked data in life science domains

The application of semantic technologies to the integration of biological data and the interoperability of bioinformatics analysis and visualization tools has been the common theme of a series of annual BioHackathons hosted in Japan for the past five years. Here we provide a review of the activities and outcomes from the BioHackathons held in 2011 in Kyoto and 2012 in Toyama. In order to efficiently implement semantic technologies in the life sciences, participants formed various sub-groups and worked on the following topics: Resource Description Framework (RDF) models for specific domains, text mining of the literature, ontology development, essential metadata for biological databases, platforms to enable efficient Semantic Web technology development and interoperability, and the development of applications for Semantic Web data. In this review, we briefly introduce the themes covered by these sub-groups. The observations made, conclusions drawn, and software development projects that emerged from these activities are discussed

Serum Wisteria Floribunda Agglutinin-Positive Mac-2 Binding Protein Values Predict the Development of Hepatocellular Carcinoma among Patients with Chronic Hepatitis C after Sustained Virological Response

Measurement of Wisteria floribundaagglutinin-positive human Mac-2 binding protein (WFA+-M2BP) in serum was recently shown to be a noninvasive method to assess liver fibrosis. The aim of this study was to evaluate the utility of serum WFA+-M2BP values to predict the development of hepatocellular carcinoma (HCC) in patients who achieved a sustained virological response (SVR) by interferon treatment. For this purpose, we retrospectively analyzed 238 patients with SVR who were treated with interferon in our department. Serum WFA+-M2BP values were measured at pre-treatment (pre-Tx), post-treatment (24 weeks after completion of interferon; post-Tx), the time of HCC diagnosis, and the last clinical visit. Of 238 patients with SVR, HCC developed in 16 (6.8%) patients. The average follow-up period was 9.1 years. The cumulative incidence of HCC was 3.4% at 5 years and 7.5% at 10 years. The median pre-Tx and post-Tx WFA+-M2BP values were 1.69 (range: 0.28 to 12.04 cutoff index (COI)) and 0.80 (range: 0.17 to 5.29 COI), respectively. The WFA+-M2BP values decreased significantly after SVR (P 60 years), sex (male), pre-Tx platelet count ( 2.0 COI) were associated with the development of HCC after SVR. Conclusion: Post-Tx WFA+-M2BP (> 2.0 COI) is associated with the risk for development of HCC among patients with SVR. The WFA+-M2BP values could be a new predictor for HCC after SVR