Project acronym MAMMASTEM
Project Molecular mechanisms of the regulation of mammary stem cell homeostasis and their subversion in cancer
Researcher (PI) Pier Paolo Di Fiore
Host Institution (HI) IFOM FONDAZIONE ISTITUTO FIRC DI ONCOLOGIA MOLECOLARE
Call Details Advanced Grant (AdG), LS3, ERC-2008-AdG
Summary Stem cells (SCs) are thought to be integral to the development and progression of cancer, and their eradication may be essential for the cure of cancer. Yet, direct proof is lacking due to our poor understanding of the molecular differences between normal and cancer SCs. We will investigate normal and cancer mammary stem cells (MSCs) by focusing on the role of the cell fate determinant Numb in two signaling axes: Numb:Notch and Numb:p53. Numb is a tumor suppressor in human breast cancer. Its expression is lost, through increased degradation, in ~50% of breast cancers. These Numbneg cancers display overall poorer prognosis. Mechanistically, loss of Numb causes increased Notch signaling and decreased p53 signaling. Thus, Numb controls both an oncogenic pathway (the Numb:Notch axis) and a tumor suppressor one (the Numb:p53 axis). We showed that Numb is asymmetrically partitioned at the first division of normal MSCs and hypothesize that loss of Numb affects the kinetics of division and MSC fate. Our specific aims are to: 1. Define the role of the Numb:Notch and Numb:p53 axes in normal and cancer MSCs. We will exploit our capacity to propagate and isolate MSCs to near-purity, for biological, biochemical and omics approaches. In this task, we will integrate knowledge derived from the analysis of real human cancers and of genetically-defined mouse models. 2. Define the broader biological context of Numb impact in stem cell biology, by analyzing the role of endocytosis in MSC fate determination. This is justified by the fact that Numb is an endocytic protein and that data in Drosophila indicate a complex role of endocytosis in cell fate specification. 3. Identify the E3 ligase responsible for Numb degradation in Numbneg breast tumors, in order to obtain druggable targets to restore Numb levels in these tumors. If successful, our work will elucidate major mechanisms of normal and cancer stem cell regulation, and provide tools for SC-specific therapeutic intervention.
Summary
Stem cells (SCs) are thought to be integral to the development and progression of cancer, and their eradication may be essential for the cure of cancer. Yet, direct proof is lacking due to our poor understanding of the molecular differences between normal and cancer SCs. We will investigate normal and cancer mammary stem cells (MSCs) by focusing on the role of the cell fate determinant Numb in two signaling axes: Numb:Notch and Numb:p53. Numb is a tumor suppressor in human breast cancer. Its expression is lost, through increased degradation, in ~50% of breast cancers. These Numbneg cancers display overall poorer prognosis. Mechanistically, loss of Numb causes increased Notch signaling and decreased p53 signaling. Thus, Numb controls both an oncogenic pathway (the Numb:Notch axis) and a tumor suppressor one (the Numb:p53 axis). We showed that Numb is asymmetrically partitioned at the first division of normal MSCs and hypothesize that loss of Numb affects the kinetics of division and MSC fate. Our specific aims are to: 1. Define the role of the Numb:Notch and Numb:p53 axes in normal and cancer MSCs. We will exploit our capacity to propagate and isolate MSCs to near-purity, for biological, biochemical and omics approaches. In this task, we will integrate knowledge derived from the analysis of real human cancers and of genetically-defined mouse models. 2. Define the broader biological context of Numb impact in stem cell biology, by analyzing the role of endocytosis in MSC fate determination. This is justified by the fact that Numb is an endocytic protein and that data in Drosophila indicate a complex role of endocytosis in cell fate specification. 3. Identify the E3 ligase responsible for Numb degradation in Numbneg breast tumors, in order to obtain druggable targets to restore Numb levels in these tumors. If successful, our work will elucidate major mechanisms of normal and cancer stem cell regulation, and provide tools for SC-specific therapeutic intervention.
Max ERC Funding
2 274 862 €
Duration
Start date: 2009-03-01, End date: 2014-02-28
Project acronym REGULATORYCIRCUITS
Project Novel Systematic Strategies for Elucidating Cellular Regulatory Circuits
Researcher (PI) Nir Friedman
Host Institution (HI) THE HEBREW UNIVERSITY OF JERUSALEM
Call Details Advanced Grant (AdG), LS2, ERC-2008-AdG
Summary The precise regulation of gene expression has been the subject of extensive scrutiny. Nonetheless, there is a big gap between genomic characterization of transcriptional responses and our predictions based on known molecular mechanisms and networks and of transcription regulation. In this proposal I argue for an approach to bridge this gap by using a novel experimental strategy that exploits the recent maturation of two technologies: the use of fluorescence reporter techniques to monitor promoter activity and high-throughput genetic manipulations for the construction of combinatorial genetic perturbations. By combining these, we will screen for genes that modulate the transcriptional response of target promoters, use genetic interactions between them to better resolve their functional dependencies, and build detailed quantitative models of transcriptional processes. We will use the budding yeast model organism, which allows for efficient manipulations, to dissect two transcriptional responses that are prototypical of many regulatory networks in living cells: [1] The early response to osmotic stress, which is mediated by at least two signaling pathways and multiple transcription factors, and [2] the central carbon metabolism response to shifts in carbon source, which involves multiple sensing and signaling pathways to maintain homeostasis. Our approach will elucidate mechanisms that are opaque to classical screens and facilitate building detailed predictive models of these responses. These results will lead to understanding of general principles that govern transcriptional networks. This is the first approach to comprehensively characterize the molecular mechanisms that modulate a transcriptional response, and arrange them in a coherent network. It will open many questions for detailed biochemical investigations, as well as set the stage to extend these ideas to use more detailed phenotypic assays and in more complex organisms.
Summary
The precise regulation of gene expression has been the subject of extensive scrutiny. Nonetheless, there is a big gap between genomic characterization of transcriptional responses and our predictions based on known molecular mechanisms and networks and of transcription regulation. In this proposal I argue for an approach to bridge this gap by using a novel experimental strategy that exploits the recent maturation of two technologies: the use of fluorescence reporter techniques to monitor promoter activity and high-throughput genetic manipulations for the construction of combinatorial genetic perturbations. By combining these, we will screen for genes that modulate the transcriptional response of target promoters, use genetic interactions between them to better resolve their functional dependencies, and build detailed quantitative models of transcriptional processes. We will use the budding yeast model organism, which allows for efficient manipulations, to dissect two transcriptional responses that are prototypical of many regulatory networks in living cells: [1] The early response to osmotic stress, which is mediated by at least two signaling pathways and multiple transcription factors, and [2] the central carbon metabolism response to shifts in carbon source, which involves multiple sensing and signaling pathways to maintain homeostasis. Our approach will elucidate mechanisms that are opaque to classical screens and facilitate building detailed predictive models of these responses. These results will lead to understanding of general principles that govern transcriptional networks. This is the first approach to comprehensively characterize the molecular mechanisms that modulate a transcriptional response, and arrange them in a coherent network. It will open many questions for detailed biochemical investigations, as well as set the stage to extend these ideas to use more detailed phenotypic assays and in more complex organisms.
Max ERC Funding
2 199 899 €
Duration
Start date: 2009-01-01, End date: 2013-12-31
Project acronym VARB
Project Variability and Robustness in Bio-molecular systems
Researcher (PI) Naama Barkai
Host Institution (HI) WEIZMANN INSTITUTE OF SCIENCE
Call Details Advanced Grant (AdG), LS2, ERC-2008-AdG
Summary Cells process information using biochemical networks of interacting proteins and genes. We wish to understand the principles that guide the design of such networks. In particular, we are interested in the interplay between variability, inherent to biological systems, and the precision of cellular computing. To better understand this interplay, we will: (1) Characterize the extent of gene expression variability and define its genetic determinants, (2) Reveal how variability is buffered and (3) Describe instances where variability (or 'noise') is an integral part of cellular computation. The study will be conducted in the multidisciplinary atmosphere of our lab, by students trained in physics, computer science, chemistry and biology. Specific issues include: 1. Gene expression variability: we will focus on the influence of chromatin structure on gene expression variability, as suggested by our bioinformatics analysis. 2. Robustness and scaling in embryonic patterning: We will study the means by which fluctuations are buffered during the development of multicellular organisms. We will focus on the robustness of morphogen gradients to protein levels, and on the ability to maintain proportionate pattern in tissues of different size. 3. Noise-driven transitions in a fluctuating environment: Our preliminary results suggest that noise plays an integral part in phosphate homeostasis in S. cerevisiae. We will characterize the role of noise in this system and study its evolutionary implications. Together, our study will shed light on one we believe to be the fundamental challenge of biological information processing: ensuring a reliable and reproducible function in the highly variable biological environment. Our study will furthermore define novel multidisciplinary, system-level paradigms and approaches that will guide further studies of bio-molecular systems
Summary
Cells process information using biochemical networks of interacting proteins and genes. We wish to understand the principles that guide the design of such networks. In particular, we are interested in the interplay between variability, inherent to biological systems, and the precision of cellular computing. To better understand this interplay, we will: (1) Characterize the extent of gene expression variability and define its genetic determinants, (2) Reveal how variability is buffered and (3) Describe instances where variability (or 'noise') is an integral part of cellular computation. The study will be conducted in the multidisciplinary atmosphere of our lab, by students trained in physics, computer science, chemistry and biology. Specific issues include: 1. Gene expression variability: we will focus on the influence of chromatin structure on gene expression variability, as suggested by our bioinformatics analysis. 2. Robustness and scaling in embryonic patterning: We will study the means by which fluctuations are buffered during the development of multicellular organisms. We will focus on the robustness of morphogen gradients to protein levels, and on the ability to maintain proportionate pattern in tissues of different size. 3. Noise-driven transitions in a fluctuating environment: Our preliminary results suggest that noise plays an integral part in phosphate homeostasis in S. cerevisiae. We will characterize the role of noise in this system and study its evolutionary implications. Together, our study will shed light on one we believe to be the fundamental challenge of biological information processing: ensuring a reliable and reproducible function in the highly variable biological environment. Our study will furthermore define novel multidisciplinary, system-level paradigms and approaches that will guide further studies of bio-molecular systems
Max ERC Funding
2 200 000 €
Duration
Start date: 2009-01-01, End date: 2013-10-31
