Shur-jen Wang | Harbin Institute Of Technology (original) (raw)

Papers by Shur-jen Wang

Research paper thumbnail of Generation of dynamic temporal and spatial concentration gradients using microfluidic devices

Lab on a chip, 2004

This paper describes a microfluidic approach to generate dynamic temporal and spatial concentrati... more This paper describes a microfluidic approach to generate dynamic temporal and spatial concentration gradients using a single microfluidic device. Compared to a previously described method that produced a single fixed gradient shape for each device, this approach combines a simple "mixer module" with gradient generating network to control and manipulate a number of different gradient shapes. The gradient profile is determined by the configuration of fluidic inputs as well as the design of microchannel network. By controlling the relative flow rates of the fluidic inputs using separate syringe pumps, the resulting composition of the inlets that feed the gradient generator can be dynamically controlled to generate temporal and spatial gradients. To demonstrate the concept and illustrate this approach, examples of devices that generate (1) temporal gradients of homogeneous concentrations, (2) linear gradients with dynamically controlled slope, baseline, and direction, and (3) ...

Research paper thumbnail of Identification of Endothelial Cell Genes Expressed in an in Vitro Model of Angiogenesis: Induction of ESM1, ig-h3, and NrCAM1

Blood vessel growth by angiogenesis plays an essential role in embryonic development, wound heali... more Blood vessel growth by angiogenesis plays an essential role in embryonic development, wound healing, and tu- mor growth. To understand the molecular cues underly- ing this process we have used the PCR-based subtractive hybridization method, representational difference analy- sis, to identify genes upregulated in endothelial cells (EC) forming tubes in 3D collagen gels, compared to mi- grating and proliferating cells

Research paper thumbnail of Differential effects of EGF gradient profiles on MDA-MB-231 breast cancer cell chemotaxis

Experimental cell research, Jan 15, 2004

Chemotaxis, directed cell migration in a gradient of chemoattractant, is an important biological ... more Chemotaxis, directed cell migration in a gradient of chemoattractant, is an important biological phenomenon that plays pivotal roles in cancer metastasis. Newly developed microfluidic chemotaxis chambers (MCC) were used to study chemotaxis of metastatic breast cancer cells, MDA-MB-231, in EGF gradients of well-defined profiles. Migration behaviors of MDA-MB-231 cells in uniform concentrations of EGF (0, 25, 50, and 100 ng/ml) and EGF (0-25, 0-50, and 0-100 ng/ml) with linear and nonlinear polynomial profiles were investigated. MDA-MB-231 cells exhibited increased speed and directionality upon stimulation with uniform concentrations of EGF. The cells were viable and motile for over 24 h, confirming the compatibility of MCC with cancer cells. Linear concentration gradients of different ranges were not effective in inducing chemotactic movement as compared to nonlinear gradients. MDA-MB-231 cells migrating in EGF gradient of 0-50 ng/ml nonlinear polynomial profile exhibited marked dire...

Research paper thumbnail of BC4GO: a full-text corpus for the BioCreative IV GO task

Gene function curation via Gene Ontology (GO) annotation is a common task among Model Organism Da... more Gene function curation via Gene Ontology (GO) annotation is a common task among Model Organism Database groups. Owing to its manual nature, this task is considered one of the bottlenecks in literature curation. There have been many previous attempts at automatic identification of GO terms and supporting information from full text. However, few systems have delivered an accuracy that is comparable with humans. One recognized challenge in developing such systems is the lack of marked sentence-level evidence text that provides the basis for making GO annotations. We aim to create a corpus that includes the GO evidence text along with the three core elements of GO annotations: (i) a gene or gene product, (ii) a GO term and (iii) a GO evidence code. To ensure our results are consistent with real-life GO data, we recruited eight professional GO curators and asked them to follow their routine GO annotation protocols. Our annotators marked up more than 5000 text passages in 200 articles for 1356 distinct GO terms. For evidence sentence selection, the inter-annotator agreement (IAA) results are 9.3% (strict) and 42.7% (relaxed) in F1-measures. For GO term selection, the IAAs are 47% (strict) and 62.9% (hierarchical). Our corpus analysis further shows that abstracts contain ∼ 10% of relevant evidence sentences and 30% distinct GO terms, while the Results/Experiment section has nearly 60% relevant sentences and >70% GO terms. Further, of those evidence sentences found in abstracts, less than one-third contain enough experimental detail to fulfill the three core criteria of a GO annotation. This result demonstrates the need of using full-text articles for text mining GO annotations. Through its use at the BioCreative IV GO (BC4GO) task, we expect our corpus to become a valuable resource for the BioNLP research community. Database URL: http://www.biocreative.org/resources/corpora/bc-iv-go-task-corpus/.

Research paper thumbnail of The Rat Genome Database 2015: genomic, phenotypic and environmental variations and disease

Nucleic acids research, Jan 28, 2015

The Rat Genome Database (RGD, http://rgd.mcw.edu) provides the most comprehensive data repository... more The Rat Genome Database (RGD, http://rgd.mcw.edu) provides the most comprehensive data repository and informatics platform related to the laboratory rat, one of the most important model organisms for disease studies. RGD maintains and updates datasets for genomic elements such as genes, transcripts and increasingly in recent years, sequence variations, as well as map positions for multiple assemblies and sequence information. Functional annotations for genomic elements are curated from published literature, submitted by researchers and integrated from other public resources. Complementing the genomic data catalogs are those associated with phenotypes and disease, including strains, QTL and experimental phenotype measurements across hundreds of strains. Data are submitted by researchers, acquired through bulk data pipelines or curated from published literature. Innovative software tools provide users with an integrated platform to query, mine, display and analyze valuable genomic and...

Research paper thumbnail of OntoMate: a text-mining tool aiding curation at the Rat Genome Database

Database : the journal of biological databases and curation, 2015

The Rat Genome Database (RGD) is the premier repository of rat genomic, genetic and physiologic d... more The Rat Genome Database (RGD) is the premier repository of rat genomic, genetic and physiologic data. Converting data from free text in the scientific literature to a structured format is one of the main tasks of all model organism databases. RGD spends considerable effort manually curating gene, Quantitative Trait Locus (QTL) and strain information. The rapidly growing volume of biomedical literature and the active research in the biological natural language processing (bioNLP) community have given RGD the impetus to adopt text-mining tools to improve curation efficiency. Recently, RGD has initiated a project to use OntoMate, an ontology-driven, concept-based literature search engine developed at RGD, as a replacement for the PubMed (http://www.ncbi.nlm.nih.gov/pubmed) search engine in the gene curation workflow. OntoMate tags abstracts with gene names, gene mutations, organism name and most of the 16 ontologies/vocabularies used at RGD. All terms/ entities tagged to an abstract ar...

Research paper thumbnail of The Rat Genome Database Curators: Who, What, Where, Why

PLoS Computational Biology, 2009

Research paper thumbnail of In vitro and in vivo Differentiation into B Cells, T Cells, and Myeloid Cells of Primitive Yolk sac Hematopoietic Precursor Cells Expanded >100Fold by Coculture with a Clonal Yolk sac Endothelial Cell Line

Proceedings of The National Academy of Sciences, 1996

The yolk sac, first site of hematopoiesis during mammalian development, contains not only hematop... more The yolk sac, first site of hematopoiesis during mammalian development, contains not only hematopoietic stem cells but also the earliest precursors of endothelial cells. We have previously shown that a nonadherent yolk sac cell population (WGA+, density <1.077, AA4.1+) can give rise to B cells, T cells, and myeloid cells both in vitro and in vivo. We now report on

Research paper thumbnail of Astrocyte regulation of human brain capillary endothelial fibrinolysis

Thrombosis Research, 2003

Research paper thumbnail of The Gene Ontology: enhancements for 2011

Nucleic Acids Research, 2012

Research paper thumbnail of Identification of Endothelial Cell Genes Expressed in an in Vitro Model of Angiogenesis: Induction of ESM-1, βig-h3, and NrCAM

Microvascular Research, 2002

Research paper thumbnail of Generation of dynamic temporal and spatial concentration gradients using microfluidic devices

Lab on a Chip, 2004

This paper describes a microfluidic approach to generate dynamic temporal and spatial concentrati... more This paper describes a microfluidic approach to generate dynamic temporal and spatial concentration gradients using a single microfluidic device. Compared to a previously described method that produced a single fixed gradient shape for each device, this approach combines a simple &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;mixer module&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; with gradient generating network to control and manipulate a number of different gradient shapes. The gradient profile is determined by the configuration of fluidic inputs as well as the design of microchannel network. By controlling the relative flow rates of the fluidic inputs using separate syringe pumps, the resulting composition of the inlets that feed the gradient generator can be dynamically controlled to generate temporal and spatial gradients. To demonstrate the concept and illustrate this approach, examples of devices that generate (1) temporal gradients of homogeneous concentrations, (2) linear gradients with dynamically controlled slope, baseline, and direction, and (3) nonlinear gradients with controlled nonlinearity are shown and their limitations are described.

Research paper thumbnail of Cell interactions in the mouse yolk sac: Vasculogenesis and hematopoiesis

Journal of Cellular Physiology, 1997

Research paper thumbnail of PRIMITIVE ENDOTHELIAL CELL LINES FROM THE PORCINE EMBRYONIC YOLK SAC

In Vitro Cellular & Developmental Biology - Animal, 2002

Research paper thumbnail of Differential effects of EGF gradient profiles on MDA-MB-231 breast cancer cell chemotaxis

Experimental Cell Research, 2004

Research paper thumbnail of Role of endothelium in the control of mouse yolk sac stem cell differentiation

Developmental & Comparative Immunology, 1998

Studies in our laboratory have shown that as early as day 8.5 of development, mouse yolk sac cell... more Studies in our laboratory have shown that as early as day 8.5 of development, mouse yolk sac cells can generate T cells when placed in a thymic microenvironment. At this stage, yolk sac cells can also differentiate into myeloid cells in vitro. B cell differentiation in vitro was achieved with day 9 yolk sac by providing a bone marrow stromal feeder layer. We have now established endothelial cell lines and clones from yolk sacs of day 8-12 mouse embryos. These vary in their ability to support stem cell maintenance and differentiation. Our principal work has been carried out with day 12 cloned endothelial cell lines. One clone supported the &amp;amp;gt; 100 fold expansion of yolk sac hematopoietic stem cells that subsequently could generate B cells, T cells and myeloid cells both in vitro and in vivo. Preliminary experiments with endothelial cells from younger embryos are also described.

Research paper thumbnail of A parallel-gradient microfluidic chamber for quantitative analysis of breast cancer cell chemotaxis

Biomedical Microdevices, 2006

Growth factor-induced chemotaxis of cancer cells is believed to play a critical role in metastasi... more Growth factor-induced chemotaxis of cancer cells is believed to play a critical role in metastasis, directing the spread of cancer from the primary tumor to secondary sites in the body. Understanding the mechanistic and quantitative behavior of cancer cell migration in growth factor gradients would greatly help in future treatment of metastatic cancers. Using a novel microfluidic chemotaxis chamber capable of simultaneously generating multiple growth factor gradients, we examined the migration of the human metastatic breast cancer cell line MDA-MB-231 in various conditions. First, we quantified and compared the migration in two gradients of epidermal growth factor (EGF) spanning different concentrations: 0-50 ng/ml and 0.1-6 ng/ml. Cells showed a stronger response in the 0-50 ng/ml gradient. However, the fact that even a shallow gradient of EGF can induce chemotaxis, and that EGF can direct migration over a large dynamic range of gradients, confirms the potency of EGF as a chemoattractant. Second, we investigated the effect of antibody against the EGF receptor (EGFR) on MDA-MB-231 chemotaxis. Quantitative analysis indicated that anti-EGFR antibody impaired both motility and directional orientation (CI = 0.03, speed = 0.71 microm/min), indicating that cell motility was induced by the activation of EGFR. The ability to compare, in terms of quantitative parameters, the effects of different pharmaceutical inhibitors, as well as subtle differences in experimental conditions, will aid in our understanding of mechanisms that drive metastasis. The microfluidic chamber described in this work will provide a platform for cell-based assays that can be used to compare the effectiveness of different pharmaceutical compounds targeting cell migration and metastasis.

Research paper thumbnail of Neutrophil Migration in Opposing Chemoattractant Gradients Using Microfluidic Chemotaxis Devices

Annals of Biomedical Engineering, 2005

Research paper thumbnail of Overview of the gene ontology task at BioCreative IV

Database : the journal of biological databases and curation, 2014

Gene ontology (GO) annotation is a common task among model organism databases (MODs) for capturin... more Gene ontology (GO) annotation is a common task among model organism databases (MODs) for capturing gene function data from journal articles. It is a time-consuming and labor-intensive task, and is thus often considered as one of the bottlenecks in literature curation. There is a growing need for semiautomated or fully automated GO curation techniques that will help database curators to rapidly and accurately identify gene function information in full-length articles. Despite multiple attempts in the past, few studies have proven to be useful with regard to assisting real-world GO curation. The shortage of sentence-level training data and opportunities for interaction between text-mining developers and GO curators has limited the advances in algorithm development and corresponding use in practical circumstances. To this end, we organized a text-mining challenge task for literature-based GO annotation in BioCreative IV. More specifically, we developed two subtasks: (i) to automaticall...

Research paper thumbnail of Generation of dynamic temporal and spatial concentration gradients using microfluidic devices

Lab on a chip, 2004

This paper describes a microfluidic approach to generate dynamic temporal and spatial concentrati... more This paper describes a microfluidic approach to generate dynamic temporal and spatial concentration gradients using a single microfluidic device. Compared to a previously described method that produced a single fixed gradient shape for each device, this approach combines a simple "mixer module" with gradient generating network to control and manipulate a number of different gradient shapes. The gradient profile is determined by the configuration of fluidic inputs as well as the design of microchannel network. By controlling the relative flow rates of the fluidic inputs using separate syringe pumps, the resulting composition of the inlets that feed the gradient generator can be dynamically controlled to generate temporal and spatial gradients. To demonstrate the concept and illustrate this approach, examples of devices that generate (1) temporal gradients of homogeneous concentrations, (2) linear gradients with dynamically controlled slope, baseline, and direction, and (3) ...

Research paper thumbnail of Identification of Endothelial Cell Genes Expressed in an in Vitro Model of Angiogenesis: Induction of ESM1, ig-h3, and NrCAM1

Blood vessel growth by angiogenesis plays an essential role in embryonic development, wound heali... more Blood vessel growth by angiogenesis plays an essential role in embryonic development, wound healing, and tu- mor growth. To understand the molecular cues underly- ing this process we have used the PCR-based subtractive hybridization method, representational difference analy- sis, to identify genes upregulated in endothelial cells (EC) forming tubes in 3D collagen gels, compared to mi- grating and proliferating cells

Research paper thumbnail of Differential effects of EGF gradient profiles on MDA-MB-231 breast cancer cell chemotaxis

Experimental cell research, Jan 15, 2004

Chemotaxis, directed cell migration in a gradient of chemoattractant, is an important biological ... more Chemotaxis, directed cell migration in a gradient of chemoattractant, is an important biological phenomenon that plays pivotal roles in cancer metastasis. Newly developed microfluidic chemotaxis chambers (MCC) were used to study chemotaxis of metastatic breast cancer cells, MDA-MB-231, in EGF gradients of well-defined profiles. Migration behaviors of MDA-MB-231 cells in uniform concentrations of EGF (0, 25, 50, and 100 ng/ml) and EGF (0-25, 0-50, and 0-100 ng/ml) with linear and nonlinear polynomial profiles were investigated. MDA-MB-231 cells exhibited increased speed and directionality upon stimulation with uniform concentrations of EGF. The cells were viable and motile for over 24 h, confirming the compatibility of MCC with cancer cells. Linear concentration gradients of different ranges were not effective in inducing chemotactic movement as compared to nonlinear gradients. MDA-MB-231 cells migrating in EGF gradient of 0-50 ng/ml nonlinear polynomial profile exhibited marked dire...

Research paper thumbnail of BC4GO: a full-text corpus for the BioCreative IV GO task

Gene function curation via Gene Ontology (GO) annotation is a common task among Model Organism Da... more Gene function curation via Gene Ontology (GO) annotation is a common task among Model Organism Database groups. Owing to its manual nature, this task is considered one of the bottlenecks in literature curation. There have been many previous attempts at automatic identification of GO terms and supporting information from full text. However, few systems have delivered an accuracy that is comparable with humans. One recognized challenge in developing such systems is the lack of marked sentence-level evidence text that provides the basis for making GO annotations. We aim to create a corpus that includes the GO evidence text along with the three core elements of GO annotations: (i) a gene or gene product, (ii) a GO term and (iii) a GO evidence code. To ensure our results are consistent with real-life GO data, we recruited eight professional GO curators and asked them to follow their routine GO annotation protocols. Our annotators marked up more than 5000 text passages in 200 articles for 1356 distinct GO terms. For evidence sentence selection, the inter-annotator agreement (IAA) results are 9.3% (strict) and 42.7% (relaxed) in F1-measures. For GO term selection, the IAAs are 47% (strict) and 62.9% (hierarchical). Our corpus analysis further shows that abstracts contain ∼ 10% of relevant evidence sentences and 30% distinct GO terms, while the Results/Experiment section has nearly 60% relevant sentences and &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;70% GO terms. Further, of those evidence sentences found in abstracts, less than one-third contain enough experimental detail to fulfill the three core criteria of a GO annotation. This result demonstrates the need of using full-text articles for text mining GO annotations. Through its use at the BioCreative IV GO (BC4GO) task, we expect our corpus to become a valuable resource for the BioNLP research community. Database URL: http://www.biocreative.org/resources/corpora/bc-iv-go-task-corpus/.

Research paper thumbnail of The Rat Genome Database 2015: genomic, phenotypic and environmental variations and disease

Nucleic acids research, Jan 28, 2015

The Rat Genome Database (RGD, http://rgd.mcw.edu) provides the most comprehensive data repository... more The Rat Genome Database (RGD, http://rgd.mcw.edu) provides the most comprehensive data repository and informatics platform related to the laboratory rat, one of the most important model organisms for disease studies. RGD maintains and updates datasets for genomic elements such as genes, transcripts and increasingly in recent years, sequence variations, as well as map positions for multiple assemblies and sequence information. Functional annotations for genomic elements are curated from published literature, submitted by researchers and integrated from other public resources. Complementing the genomic data catalogs are those associated with phenotypes and disease, including strains, QTL and experimental phenotype measurements across hundreds of strains. Data are submitted by researchers, acquired through bulk data pipelines or curated from published literature. Innovative software tools provide users with an integrated platform to query, mine, display and analyze valuable genomic and...

Research paper thumbnail of OntoMate: a text-mining tool aiding curation at the Rat Genome Database

Database : the journal of biological databases and curation, 2015

The Rat Genome Database (RGD) is the premier repository of rat genomic, genetic and physiologic d... more The Rat Genome Database (RGD) is the premier repository of rat genomic, genetic and physiologic data. Converting data from free text in the scientific literature to a structured format is one of the main tasks of all model organism databases. RGD spends considerable effort manually curating gene, Quantitative Trait Locus (QTL) and strain information. The rapidly growing volume of biomedical literature and the active research in the biological natural language processing (bioNLP) community have given RGD the impetus to adopt text-mining tools to improve curation efficiency. Recently, RGD has initiated a project to use OntoMate, an ontology-driven, concept-based literature search engine developed at RGD, as a replacement for the PubMed (http://www.ncbi.nlm.nih.gov/pubmed) search engine in the gene curation workflow. OntoMate tags abstracts with gene names, gene mutations, organism name and most of the 16 ontologies/vocabularies used at RGD. All terms/ entities tagged to an abstract ar...

Research paper thumbnail of The Rat Genome Database Curators: Who, What, Where, Why

PLoS Computational Biology, 2009

Research paper thumbnail of In vitro and in vivo Differentiation into B Cells, T Cells, and Myeloid Cells of Primitive Yolk sac Hematopoietic Precursor Cells Expanded >100Fold by Coculture with a Clonal Yolk sac Endothelial Cell Line

Proceedings of The National Academy of Sciences, 1996

The yolk sac, first site of hematopoiesis during mammalian development, contains not only hematop... more The yolk sac, first site of hematopoiesis during mammalian development, contains not only hematopoietic stem cells but also the earliest precursors of endothelial cells. We have previously shown that a nonadherent yolk sac cell population (WGA+, density <1.077, AA4.1+) can give rise to B cells, T cells, and myeloid cells both in vitro and in vivo. We now report on

Research paper thumbnail of Astrocyte regulation of human brain capillary endothelial fibrinolysis

Thrombosis Research, 2003

Research paper thumbnail of The Gene Ontology: enhancements for 2011

Nucleic Acids Research, 2012

Research paper thumbnail of Identification of Endothelial Cell Genes Expressed in an in Vitro Model of Angiogenesis: Induction of ESM-1, βig-h3, and NrCAM

Microvascular Research, 2002

Research paper thumbnail of Generation of dynamic temporal and spatial concentration gradients using microfluidic devices

Lab on a Chip, 2004

This paper describes a microfluidic approach to generate dynamic temporal and spatial concentrati... more This paper describes a microfluidic approach to generate dynamic temporal and spatial concentration gradients using a single microfluidic device. Compared to a previously described method that produced a single fixed gradient shape for each device, this approach combines a simple &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;mixer module&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; with gradient generating network to control and manipulate a number of different gradient shapes. The gradient profile is determined by the configuration of fluidic inputs as well as the design of microchannel network. By controlling the relative flow rates of the fluidic inputs using separate syringe pumps, the resulting composition of the inlets that feed the gradient generator can be dynamically controlled to generate temporal and spatial gradients. To demonstrate the concept and illustrate this approach, examples of devices that generate (1) temporal gradients of homogeneous concentrations, (2) linear gradients with dynamically controlled slope, baseline, and direction, and (3) nonlinear gradients with controlled nonlinearity are shown and their limitations are described.

Research paper thumbnail of Cell interactions in the mouse yolk sac: Vasculogenesis and hematopoiesis

Journal of Cellular Physiology, 1997

Research paper thumbnail of PRIMITIVE ENDOTHELIAL CELL LINES FROM THE PORCINE EMBRYONIC YOLK SAC

In Vitro Cellular & Developmental Biology - Animal, 2002

Research paper thumbnail of Differential effects of EGF gradient profiles on MDA-MB-231 breast cancer cell chemotaxis

Experimental Cell Research, 2004

Research paper thumbnail of Role of endothelium in the control of mouse yolk sac stem cell differentiation

Developmental & Comparative Immunology, 1998

Studies in our laboratory have shown that as early as day 8.5 of development, mouse yolk sac cell... more Studies in our laboratory have shown that as early as day 8.5 of development, mouse yolk sac cells can generate T cells when placed in a thymic microenvironment. At this stage, yolk sac cells can also differentiate into myeloid cells in vitro. B cell differentiation in vitro was achieved with day 9 yolk sac by providing a bone marrow stromal feeder layer. We have now established endothelial cell lines and clones from yolk sacs of day 8-12 mouse embryos. These vary in their ability to support stem cell maintenance and differentiation. Our principal work has been carried out with day 12 cloned endothelial cell lines. One clone supported the &amp;amp;gt; 100 fold expansion of yolk sac hematopoietic stem cells that subsequently could generate B cells, T cells and myeloid cells both in vitro and in vivo. Preliminary experiments with endothelial cells from younger embryos are also described.

Research paper thumbnail of A parallel-gradient microfluidic chamber for quantitative analysis of breast cancer cell chemotaxis

Biomedical Microdevices, 2006

Growth factor-induced chemotaxis of cancer cells is believed to play a critical role in metastasi... more Growth factor-induced chemotaxis of cancer cells is believed to play a critical role in metastasis, directing the spread of cancer from the primary tumor to secondary sites in the body. Understanding the mechanistic and quantitative behavior of cancer cell migration in growth factor gradients would greatly help in future treatment of metastatic cancers. Using a novel microfluidic chemotaxis chamber capable of simultaneously generating multiple growth factor gradients, we examined the migration of the human metastatic breast cancer cell line MDA-MB-231 in various conditions. First, we quantified and compared the migration in two gradients of epidermal growth factor (EGF) spanning different concentrations: 0-50 ng/ml and 0.1-6 ng/ml. Cells showed a stronger response in the 0-50 ng/ml gradient. However, the fact that even a shallow gradient of EGF can induce chemotaxis, and that EGF can direct migration over a large dynamic range of gradients, confirms the potency of EGF as a chemoattractant. Second, we investigated the effect of antibody against the EGF receptor (EGFR) on MDA-MB-231 chemotaxis. Quantitative analysis indicated that anti-EGFR antibody impaired both motility and directional orientation (CI = 0.03, speed = 0.71 microm/min), indicating that cell motility was induced by the activation of EGFR. The ability to compare, in terms of quantitative parameters, the effects of different pharmaceutical inhibitors, as well as subtle differences in experimental conditions, will aid in our understanding of mechanisms that drive metastasis. The microfluidic chamber described in this work will provide a platform for cell-based assays that can be used to compare the effectiveness of different pharmaceutical compounds targeting cell migration and metastasis.

Research paper thumbnail of Neutrophil Migration in Opposing Chemoattractant Gradients Using Microfluidic Chemotaxis Devices

Annals of Biomedical Engineering, 2005

Research paper thumbnail of Overview of the gene ontology task at BioCreative IV

Database : the journal of biological databases and curation, 2014

Gene ontology (GO) annotation is a common task among model organism databases (MODs) for capturin... more Gene ontology (GO) annotation is a common task among model organism databases (MODs) for capturing gene function data from journal articles. It is a time-consuming and labor-intensive task, and is thus often considered as one of the bottlenecks in literature curation. There is a growing need for semiautomated or fully automated GO curation techniques that will help database curators to rapidly and accurately identify gene function information in full-length articles. Despite multiple attempts in the past, few studies have proven to be useful with regard to assisting real-world GO curation. The shortage of sentence-level training data and opportunities for interaction between text-mining developers and GO curators has limited the advances in algorithm development and corresponding use in practical circumstances. To this end, we organized a text-mining challenge task for literature-based GO annotation in BioCreative IV. More specifically, we developed two subtasks: (i) to automaticall...