Project description:Chickarmane2006 - Stem cell switch reversible Kinetic modeling approach of the transcriptional dynamics of the embryonic stem cell switch. This model is described in the article: Transcriptional dynamics of the embryonic stem cell switch. Chickarmane V, Troein C, Nuber UA, Sauro HM, Peterson C PLoS Computational Biology. 2006; 2(9):e123 Abstract: Recent ChIP experiments of human and mouse embryonic stem cells have elucidated the architecture of the transcriptional regulatory circuitry responsible for cell determination, which involves the transcription factors OCT4, SOX2, and NANOG. In addition to regulating each other through feedback loops, these genes also regulate downstream target genes involved in the maintenance and differentiation of embryonic stem cells. A search for the OCT4-SOX2-NANOG network motif in other species reveals that it is unique to mammals. With a kinetic modeling approach, we ascribe function to the observed OCT4-SOX2-NANOG network by making plausible assumptions about the interactions between the transcription factors at the gene promoter binding sites and RNA polymerase (RNAP), at each of the three genes as well as at the target genes. We identify a bistable switch in the network, which arises due to several positive feedback loops, and is switched on/off by input environmental signals. The switch stabilizes the expression levels of the three genes, and through their regulatory roles on the downstream target genes, leads to a binary decision: when OCT4, SOX2, and NANOG are expressed and the switch is on, the self-renewal genes are on and the differentiation genes are off. The opposite holds when the switch is off. The model is extremely robust to parameter changes. In addition to providing a self-consistent picture of the transcriptional circuit, the model generates several predictions. Increasing the binding strength of NANOG to OCT4 and SOX2, or increasing its basal transcriptional rate, leads to an irreversible bistable switch: the switch remains on even when the activating signal is removed. Hence, the stem cell can be manipulated to be self-renewing without the requirement of input signals. We also suggest tests that could discriminate between a variety of feedforward regulation architectures of the target genes by OCT4, SOX2, and NANOG. This model is hosted on BioModels Database and identified by: MODEL7957907314 . To cite BioModels Database, please use: BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models . To the extent possible under law, all copyright and related or neighbouring rights to this encoded model have been dedicated to the public domain worldwide. Please refer to CC0 Public Domain Dedication for more information.

Project description:Chickarmane2006 - Stem cell switch irreversible Kinetic modeling approach of the transcriptional dynamics of the embryonic stem cell switch. This model is described in the article: Transcriptional dynamics of the embryonic stem cell switch. Chickarmane V, Troein C, Nuber UA, Sauro HM, Peterson C PLoS Computational Biology. 2006; 2(9):e123 Abstract: Recent ChIP experiments of human and mouse embryonic stem cells have elucidated the architecture of the transcriptional regulatory circuitry responsible for cell determination, which involves the transcription factors OCT4, SOX2, and NANOG. In addition to regulating each other through feedback loops, these genes also regulate downstream target genes involved in the maintenance and differentiation of embryonic stem cells. A search for the OCT4-SOX2-NANOG network motif in other species reveals that it is unique to mammals. With a kinetic modeling approach, we ascribe function to the observed OCT4-SOX2-NANOG network by making plausible assumptions about the interactions between the transcription factors at the gene promoter binding sites and RNA polymerase (RNAP), at each of the three genes as well as at the target genes. We identify a bistable switch in the network, which arises due to several positive feedback loops, and is switched on/off by input environmental signals. The switch stabilizes the expression levels of the three genes, and through their regulatory roles on the downstream target genes, leads to a binary decision: when OCT4, SOX2, and NANOG are expressed and the switch is on, the self-renewal genes are on and the differentiation genes are off. The opposite holds when the switch is off. The model is extremely robust to parameter changes. In addition to providing a self-consistent picture of the transcriptional circuit, the model generates several predictions. Increasing the binding strength of NANOG to OCT4 and SOX2, or increasing its basal transcriptional rate, leads to an irreversible bistable switch: the switch remains on even when the activating signal is removed. Hence, the stem cell can be manipulated to be self-renewing without the requirement of input signals. We also suggest tests that could discriminate between a variety of feedforward regulation architectures of the target genes by OCT4, SOX2, and NANOG. This model is hosted on BioModels Database and identified by: MODEL7957942740 . To cite BioModels Database, please use: BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models . To the extent possible under law, all copyright and related or neighbouring rights to this encoded model have been dedicated to the public domain worldwide. Please refer to CC0 Public Domain Dedication for more information.

Project description:The primary objective of the two phase PERMAD trial is the evaluation of the impact of a personalized marker-driven treatment approach with early detection of progression and modification of treatment on cytokines and angiogenic factors (CAF) and efficacy. In regard of the two parts, the primary objective of the run-in phase (n=50 patients) with conventional switch of chemotherapy together with the anti-angiogenic agent is the determination of a distinct cytokines and angiogenic factor (CAF) profile during treatment with FOLFOX and bevacizumab, which allows early detection/prediction of progressive disease. The primary objective of the marker-driven randomized part (n=150 patients) with marker-driven switch of antiangiogenic agent and maintenance of chemotherapy is the evaluation of the efficacy of an early marker-driven switch of anti-angiogenic treatment (bevacizumab to aflibercept) This is a multicentre, multinational, open labeled, prospective, randomized, controlled phase II study designed to assess the clinical utility of an early marker driven change of anti-angiogenic treatment (bevacizumab to aflibercept) maintaining the chemotherapy backbone until definite radiological progression in first line treatment of patients with metastatic colorectal cancer. After completing the run in phase of the study, with at least 30 patients completing their first line treatment (due to progression, secondary resection or toxicity) and being evaluable for CAF analyses, the results will be reviewed by an Independent Data Monitoring Committee (IDMC). Based on that review the decision to continue with, modify or cancel the randomized part will be made. The primary endpoint of the run-in phase with conventional switch of chemotherapy together with the anti-angiogenic agent is: • Progression free survival (PFS1) of first line treatment The primary endpoint of the randomized part with marker-driven switch of antiangiogenic agent and maintenance of chemotherapy is: • Progression free survival rate at 6 months (PFSR@6) after first cycle after randomization.

Project description:Chickarmane2008 - Stem cell lineage - NANOG GATA-6 switch In this work, a dynamical model of lineage determination based upon a minimal circuit, as discussed in PMID: 17215298 , which contains the Oct4/Sox2/Nanog core as well its interaction with a few other key genes is discussed. This model is described in the article: A computational model for understanding stem cell, trophectoderm and endoderm lineage determination. Chickarmane V, Peterson C PloS one. 2008, 3(10):e3478 Abstract: BACKGROUND: Recent studies have associated the transcription factors, Oct4, Sox2 and Nanog as parts of a self-regulating network which is responsible for maintaining embryonic stem cell properties: self renewal and pluripotency. In addition, mutual antagonism between two of these and other master regulators have been shown to regulate lineage determination. In particular, an excess of Cdx2 over Oct4 determines the trophectoderm lineage whereas an excess of Gata-6 over Nanog determines differentiation into the endoderm lineage. Also, under/over-expression studies of the master regulator Oct4 have revealed that some self-renewal/pluripotency as well as differentiation genes are expressed in a biphasic manner with respect to the concentration of Oct4. METHODOLOGY/ PRINCIPAL FINDINGS: We construct a dynamical model of a minimalistic network, extracted from ChIP-on-chip and microarray data as well as literature studies. The model is based upon differential equations and makes two plausible assumptions; activation of Gata-6 by Oct4 and repression of Nanog by an Oct4-Gata-6 heterodimer. With these assumptions, the results of simulations successfully describe the biphasic behavior as well as lineage commitment. The model also predicts that reprogramming the network from a differentiated state, in particular the endoderm state, into a stem cell state, is best achieved by over-expressing Nanog, rather than by suppression of differentiation genes such as Gata-6. CONCLUSIONS: The computational model provides a mechanistic understanding of how different lineages arise from the dynamics of the underlying regulatory network. It provides a framework to explore strategies of reprogramming a cell from a differentiated state to a stem cell state through directed perturbations. Such an approach is highly relevant to regenerative medicine since it allows for a rapid search over the host of possibilities for reprogramming to a stem cell state. This model is hosted on BioModels Database and identified by: MODEL8389825246 . To cite BioModels Database, please use: BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models . To the extent possible under law, all copyright and related or neighbouring rights to this encoded model have been dedicated to the public domain worldwide. Please refer to CC0 Public Domain Dedication for more information.

			Action	DRS
	SRR9025765_1.fastq.gz	Fastqsanger.gz
	SRR9025765_2.fastq.gz	Fastqsanger.gz
	SRR9025766_1.fastq.gz	Fastqsanger.gz
	SRR9025766_2.fastq.gz	Fastqsanger.gz
	SRR9025767_1.fastq.gz	Fastqsanger.gz

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A stem cell-driven lymphoangiogenic switch (ChIP-seq)

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