ERC FUNDED PROJECTS

Acute Myeloid Leukemia (AML), the most common leukemia diagnosed in adults, represents the paradigm of resistance to front-line therapies in hematology. Indeed, AML is so genetically complex that only few targeted therapies are currently tested in this disease and chemotherapy remains the only standard treatment for AML since the past four decades. Despite an initial sustained remission achieved by chemotherapeutic agents, almost all patients relapse with a chemoresistant minimal residual disease (MRD). The goal of my proposal is to characterize the still poorly understood biological mechanisms underlying persistence and emergence of MRD. MRD is the consequence of the re-expansion of leukemia-initiating cells that are intrinsically more resistant to chemotherapy. This cell fraction may be stochastically more prone to survive front-line therapy regardless of their mutational status (the stochastic model), or genetically predetermined to resist by virtue of a collection of chemoprotective mutations (the mutational model). I have already generated in mice, by consecutive rounds of chemotherapy, a stochastic MLL-AF9-driven chemoresistance model that I examined by RNA-sequencing. I will pursue the comprehensive cell autonomous and cell non-autonomous characterization of this chemoresistant AML disease using whole-exome and ChIP-sequencing. To establish a mutationally-induced chemoresistant mouse model, I will conduct an innovative in vivo screen using pooled mutant open reading frame and shRNA libraries in order to predict which combinations of mutations, among those already known in AML, actively promote chemoresistance. Finally, by combining genomic profiling and in vivo shRNA screening experiments, I will decipher the molecular mechanisms and identify the functional effectors of these two modes of resistance. Ultimately, I will then be able to firmly establish the fundamental relevance of the stochastic and/or the mutational model of chemoresistance for MRD genesis.

1 500 000 €

Start date: 2018-03-01, End date: 2023-02-28

Our research interests lie in breaking new ground in studying mechanism-based functions of AP-1 (Fos/Jun) in vivo with the aim of obtaining a more global perspective on AP-1 in human physiology and disease/cancer. The unresolved issues regarding the AP-1 subunit composition will be tackled biochemically and genetically in various cell types including bone, liver and skin, the primary organs affected by altered AP-1 activity. I plan to utilize the knowledge gained on AP-1 functions in the mouse and transfer it to human disease. The opportunities here lie in exploiting the knowledge of AP-1 target genes and utilizing this information to interfere with pathways involved in normal physiology and disease/cancer. The past investigations revealed that the functions of AP-1 are an essential node at the crossroads between life and death in different cellular systems. I plan to further exploit our findings and concentrate on utilising better mouse models to define these connections. The emphasis will be on identifying molecular signatures and potential treatments in models for cancer, inflammatory and fibrotic diseases. Exploring genetically modified stem cell-based therapies in murine and human cells is an ongoing challenge I would like to meet in the forthcoming years at the CNIO. In addition, the mouse models will be used for mechanism-driven therapeutic strategies and these studies will be undertaken in collaboration with the Experimental Therapeutics Division and the service units such as the tumor bank. The project proposal is divided into 6 Goals (see also Figure 1): Some are a logical continuation based on previous work with completely new aspects (Goal 1-2), some focussing on in depth molecular analyses of disease models with innovative and unconventional concepts, such as for inflammation and cancer, psoriasis and fibrosis (Goal 3-5). A final section is devoted to mouse and human ES cells and their impact for regenerative medicine in bone diseases and cancer.

2 500 000 €

Start date: 2009-11-01, End date: 2015-10-31

Non-Alcoholic Fatty Liver Disease (NAFLD), a disease characterized by accumulation of lipid droplets in the liver, is the major precursor for liver failure and liver cancer, and constitutes a global health challenge. An estimated 25% of the adult population suffers from NAFLD, but no FDA approved drugs are available to treat this condition. Obesity is a major NAFLD risk factor and weight-loss improves disease severity in obese patients. Bariatric surgeries are an effective treatment for obesity when lifestyle modifications fail and often lead to improvement in NAFLD and type 2 diabetes. The overreaching objective of this proposal is to combine bariatric surgery in mice and humans with advanced molecular and computational analyses to discover novel, weight-loss independent mechanisms that lead to NAFLD alleviation, and harness them to treat NAFLD. In preliminary studies, I discovered that bariatric surgery clears lipid droplets from the livers of obese db/db mice without inducing weight-loss. Using metabolic and computational analysis, I found that bariatric surgery shifts hepatic gene expression and blood metabolome of post-bariatric patients to a new trajectory, distinct from lean or sick patients. Data analysis revealed the transcription factor Egr1 and one-carbon and choline metabolism to be key drivers of weight-loss independent effects of bariatric surgery. I will use two NAFLD mouse models that do not lose weight after bariatric surgery to characterize livers of mice post-surgery. Human patients do lose weight following surgery, therefore I will use computational methods to elucidate weight-independent pathways induced by surgery, by comparing livers of lean patients to those of NAFLD patients before and shortly after bariatric surgery. Candidate pathways will be studied by metabolic flux analysis and manipulated genetically, with the ultimate goal of reaching systems-levels understanding of NAFLD and identifying surgery-mimetic therapies for this disease.

1 499 354 €

Start date: 2018-11-01, End date: 2023-10-31

A fundamental challenge of pancreas biology is to understand and manipulate the determinants of beta cell mass. The homeostatic maintenance of adult beta cell mass relies largely on replication of differentiated beta cells, but the triggers and signaling pathways involved remain poorly understood. Here I propose to investigate the physiological and molecular mechanisms that control beta cell replication. First, novel transgenic mouse tools will be used to isolate live replicating beta cells and to examine the genetic program of beta cell replication in vivo. Information gained will provide insights into the molecular biology of cell division in vivo. Additionally, these experiments will address critical unresolved questions in beta cell biology, for example whether duplication involves transient dedifferentiation. Second, genetic and pharmacologic tools will be used to dissect the signaling pathways controlling the entry of beta cells to the cell division cycle, with emphasis on the roles of glucose and insulin, the key physiological input and output of beta cells. The expected outcome of these studies is a detailed molecular understanding of the homeostatic maintenance of beta cell mass, describing how beta cell function is linked to beta cell number in vivo. This may suggest new targets and concepts for pharmacologic intervention, towards the development of regenerative therapy strategies in diabetes. More generally, the experiments will shed light on one of the greatest mysteries of developmental biology, namely how organs achieve and maintain their correct size. A fundamental challenge of pancreas biology is to understand and manipulate the determinants of beta cell mass. The homeostatic maintenance of adult beta cell mass relies largely on replication of differentiated beta cells, but the triggers and signaling pathways involved remain poorly understood. Here I propose to investigate the physiological and molecular mechanisms that control beta cell replication. First, novel transgenic mouse tools will be used to isolate live replicating beta cells and to examine the genetic program of beta cell replication in vivo. Information gained will provide insights into the molecular biology of cell division in vivo. Additionally, these experiments will address critical unresolved questions in beta cell biology, for example whether duplication involves transient dedifferentiation. Second, genetic and pharmacologic tools will be used to dissect the signaling pathways controlling the entry of beta cells to the cell division cycle, with emphasis on the roles of glucose and insulin, the key physiological input and output of beta cells. The expected outcome of these studies is a detailed molecular understanding of the homeostatic maintenance of beta cell mass, describing how beta cell function is linked to beta cell number in vivo. This may suggest new targets and concepts for pharmacologic intervention, towards the development of regenerative therapy strategies in diabetes. More generally, the experiments will shed light on one of the greatest mysteries of developmental biology, namely how organs achieve and maintain their correct size.

1 445 000 €

Start date: 2010-09-01, End date: 2015-08-31