Biomedical subjects

Yongde Bao

Publications and source records attributed to Yongde Bao.

4 recordsLinked to original sources

PubMed2004

The role of Shc and insulin-like growth factor 1 receptor in mediating the translocation of estrogen receptor alpha to the plasma membrane.

Our previous studies demonstrated that 17beta-estradiol (E2) rapidly induces the interaction of estrogen receptor alpha (ERalpha) with the adapter protein Shc, the translocation of ERalpha to the cell membrane, and the formation of dynamic membrane structures in MCF-7 breast cancer cells. The present study examined how E2 causes ERalpha to translocate to the region of the plasma membrane and focused on mechanisms whereby Shc and the insulin-like growth factor-1 receptor (IGF-1R) mediate this process. Shc physically interacts with IGF-1R in the plasma membrane, and E2 activates IGF-1R. We reasoned that ERalpha, when bound to Shc, would be directed to the region of the plasma membrane by the same processes, causing membrane translocation of Shc. We confirmed that E2 rapidly induced IGF-1R phosphorylation and demonstrated that E2 induced formation of a ternary protein complex among Shc, ERalpha, and IGF-1R. Knock down of Shc with a specific small inhibitory RNA decreased the association of ERalpha with IGF-1R by 87%, suggesting that Shc is a crucial molecule in the formation of this ternary complex. Confocal microscopy studies provided further confirmation of the functional roles of Shc and the IGF-1R in the translocation of ERalpha to the region of the membrane. Down-regulation of Shc, ERalpha, or IGF-1R with specific small inhibitory RNAs all blocked E2-induced mitogen-activated protein kinase phosphorylation. Together, our results demonstrate that Shc and IGF-1R serve as key elements in the translocation of ERalpha to the cell membrane and in the facilitation of ERalpha-mediated rapid E2 action.

Adaptor Proteins, Signal Transducing↗

PubMed2004

GeneX Va: VBC open source microarray database and analysis software.

Developed by the Virginia Bioinformatics Consortium (VBC), GeneX Va is an open source, freeware database and bioinformatics analysis software for archiving and analyzing Affymetrix GeneChip data. It provides an integrated framework for management, documentation, and analysis of microarray experiments and data to support a range of users, from individual research laboratories to institutional microarray facilities. GeneX Va also provides web-based access to a PostgreSQL relational database system with a comprehensive security system. Data can be extracted from the database and delivered to interactive or scriptable statistical analysis protocols. The security system allows each investigator to manage their own array data and analysis output files and also provides custom access privileges for other users, groups, and internal/external collaborators. The analysis interface uses "Analysis Trees," an innovative user interface that allows researchers to interactively create a tree-structured flow chart of analysis routines. The latest GeneX Va software is available from and can be freely downloaded at the Sourceforge web site http://va-genex.sourceforge.net. To allow researchers to access the database and analysis capabilities of the GeneX Va system, microarray data from many VBC GeneChip experiments have been deposited into a public section of the GeneX Va system at the University of Virginia. The VBC GeneX Va sites, which include documentation, are at http://genes.med.virginia.edu/ of the University of Virginia and at http://genex.csbc.vcu.edu/ of the Virginia Commonwealth University.

Computer Security↗

PubMed2003

Use of microarrays for investigating the subtoxic effects of snake venoms: insights into venom-induced apoptosis in human umbilical vein endothelial cells.

The pathological effects of only a small percentage of the total number of protein components of snake venoms are well documented, yet this knowledge has led to a general understanding of the physiological consequences of snake venom poisoning. The aim of this study was to assess the effect of subpathological levels of Crotalus atrox (Western diamondback rattlesnake) and Bothrops jararaca (Jararaca) snake venoms on the gene expression profile of human umbilical vein endothelial cells (HUVEC) in culture. Analysis of the data demonstrated that HUVECs treated with C. atrox venom had 33 genes up-regulated with significant fold changes of 1.5 or greater compared to untreated control cells. Ten genes were down-regulated with 1.5 or greater fold changes. In cells treated with B. jararaca venom, 33 genes were observed to be up-regulated and 11 genes were down-regulated with a fold change of 1.5 or more. More than half of the up-regulated genes and approximately half of the down-regulated genes detected in cells treated with the venoms were found in both data sets underscoring both the similarities and differences between the two venoms. Ontological categorization of the up-regulated genes from endothelial cells treated with either C. atrox or B. jararaca venom gave the cell growth/maintenance and signal transducer groups as having the most members. The ontology of the down-regulated genes from both venom-treated cell samples was more varied but interestingly, the predominant ontology class was also cell growth/maintenance. Many of the up-regulated genes are involved in the Fas ligand/TNF-alpha receptor apoptotic pathway. In summary, these experiments demonstrate the power of gene expression profiling to explore the subtoxic effects of venoms on gene expression and highlight its potential for the discovery of novel insights into a variety of biological processes and signal transduction pathways. Furthermore, these studies illustrate the subtle functional differences between similar venoms that are not always evident from standard analyses.

Animals↗

PubMed2002

Linkage of rapid estrogen action to MAPK activation by ERalpha-Shc association and Shc pathway activation.

E2 rapidly activates MAPK in breast cancer cells, and the mechanism for this effect has not been fully identified. Since growth factor-induced MAPK activation involves signaling via the adapter protein Shc (Src-homology and collagen homology) and its association with membrane receptors, we hypothesized that breast cancer cells utilize similar signaling mechanisms in response to E2. In the present study, we demonstrated that E2 rapidly induced Shc phosphorylation and Shc-Grb2 (growth factor receptor binding protein 2)-Sos (son of sevenless) complex formation in MCF-7 cells. Overexpression of dominant negative Shc blocked the effect of E2 on MAPK, indicating a critical role of Shc in E2 action. Using selective inhibitors, we also demonstrated that ERalpha and Src are upstream regulators of Shc. A rapid physical association between ERalpha and Shc upon E2 stimulation further evidenced the role of ERalpha on Shc activation. Mutagenesis studies showed that the phosphotyrosine binding and SH2 domains of Shc are required to interact with the activation function 1, but not activation function 2, domain of ERalpha. Using a glutathione-S-transferase-Shc pull-down assay, we demonstrated that this ERalpha-Shc association was direct. Biological consequences of this pathway were further investigated at the genomic and nongenomic levels. E2 stimulated MAPK-mediated Elk-1 transcriptional activity. Confocal microscopy studies showed that E2 rapidly induced formation of membrane ruffles, pseudopodia, and ERalpha membrane translocation. The E2-induced morphological changes were prevented by antiestrogen. Together our results demonstrate that ERalpha can mediate the rapid effects of E2 on Shc, MAPK, Elk-1, and morphological changes in breast cancer cells

Adaptor Proteins, Signal Transducing↗