ERC FUNDED PROJECTS

The possibility to artificially induce and expand in vitro tissue-specific stem cells (SCs) is an important goal for regenerative medicine, to understand organ physiology, for in vitro modeling of human diseases and many other applications. Here we found that this goal can be achieved in the culture dish by transiently inducing expression of YAP or TAZ - nuclear effectors of the Hippo and biomechanical pathways - into primary/terminally differentiated cells of distinct tissue origins. Moreover, YAP/TAZ are essential endogenous factors that preserve ex-vivo naturally arising SCs of distinct tissues. In this grant, we aim to gain insights into YAP/TAZ molecular networks (upstream regulators and downstream targets) involved in somatic SC reprogramming and SC identity. Our studies will entail the identification of the genetic networks and epigenetic changes controlled by YAP/TAZ during cell de-differentiation and the re-acquisition of SC-traits in distinct cell types. We will also investigate upstream inputs establishing YAP/TAZ activity, with particular emphasis on biomechanical and cytoskeletal cues that represent overarching regulators of YAP/TAZ in tissues. For many tumors, it appears that acquisition of an immature, stem-like state is a prerequisite for tumor progression and an early step in oncogene-mediated transformation. YAP/TAZ activation is widespread in human tumors. However, a connection between YAP/TAZ and oncogene-induced cell plasticity has never been investigated. We will also pursue some intriguing preliminary results and investigate how oncogenes and chromatin remodelers may link to cell mechanics, and the plasticity of the differentiated and SC states by controlling YAP/TAZ. In sum, this research should advance our understanding of the cellular and molecular basis underpinning organ growth, tissue regeneration and tumor initiation.

2 498 934 €

Start date: 2015-09-01, End date: 2021-08-31

The “Cancer Stem Cell (CSC) Hypothesis” postulates that the capacity to maintain tumour growth is owned by rare cancer cells, the CSCs, endowed with self-renewal properties. This hypothesis implies that CSCs must be eliminated to achieve cancer cure. Nevertheless, direct proof is still lacking, and recent findings challenge our concepts of CSCs, showing the limits of the CSC-defining assay (transplantation) and suggesting that CSC-identity might be context-dependent. We found two properties of CSCs self-renewal that are indispensable for the maintenance of an expanding CSC-pool and tumour growth: increased frequency of symmetric divisions, due to inactivation of the p53 tumour suppressor, and increased replicative potential, due to up-regulation of the cell-cycle inhibitor p21. We will now investigate: i) How loss of p53 in tumours leads to expansion of the CSC pool, by testing the hypothesis that p53-loss activates the Myc oncogene which induces CSC-reprogramming of differentiated cancer cells. ii) Whether p53-independent pathways are also implicated, by in vivo shRNA screens of primary tumours or normal progenitors to identify pathways involved, respectively, in CSC self-renewal or inhibition of SC-reprogramming. iii) How p21-induced cell-cycle arrest protects CSCs from self-renewal exhaustion, by investigating regulation of cell-cycle recruitment of quiescent CSCs. iv) Whether activation of p21 in CSCs induces a mutator phenotype, due to its ability to activate DNA repair, by investigating mechanisms of DNA-damage, mutation rates, and relevance of CSC mutations for development of chemoresistance. We will test self-renewal functions in a transplantation-independent assay, based on tumour re-growth in vivo after cytotoxic treatments and “clonal tracking” of re-growing tumours (using barcoded lentiviral libraries). Our long-term goal is the identification of CSC-specific targets that could be used to create the basis for CSC-specific pharmacological intervention.

2 500 000 €

Start date: 2014-07-01, End date: 2019-06-30

The c-myc proto-oncogene is a general driving force in cancer. The cmyc product (Myc) is a transcription factor that binds thousands of genomic loci. However, the identity of the Myc-target genes that influence tumor development, as well as the mechanisms through which Myc acts on these genes, remain most elusive questions in the field. We will use next-generation DNA sequencing to create a multi-layered set of genome-wide profiles. We will analyze cultured mouse cells and developing tumors, the latter in a transgenic model of Myc-induced lymphoma. The profiles will include (i.) quantitative mapping of the RNA transcriptome (coding, non-coding and small RNAs), (ii.) protein-DNA interaction profiles, (iii.) epigenome profiling, (iv.) 3D-folding of genomic DNA, (v.) mutational analysis. These datasets will provide broad views and will answer pointed questions about the action of Myc. We will address the hypothesis that many Myc target genes may not be regulated at the level of net mRNA accumulation, but rather of co-transcriptional processing events. We will provide maps for the RNA-Polymerase II complex, transcriptional co-factors and histone-modifying enzymes. We will whether the Myc-binding sites that do not map within promoters may act as enhancers and/or replication origins. We will address the hypothesis that Myc contributes to reprogramming of the genome independently from its localized effects on target genes. We will also ask which genes are targets of mutations and/or epigenetic silencing in Myc-induced lymphoma. High-throughput functional genomics will be used to address which genes suppress or promote Myc-induced lymphoma. Altogether, our data will provide an unprecedented level of insight into Myc function and into the early stages of tumor progression.

2 494 000 €

Start date: 2011-07-01, End date: 2016-06-30

Endothelial cells (ECs) exhibit a remarkable and unique plasticity in terms of redox biology and metabolism. They can quickly adapt to oxygen, nitric oxide and metabolic variations. Therefore, EC must be equipped with a selective and unique repertoire of redox and metabolic mechanisms, that play a crucial role to preserve redox balance, and adjust metabolic conditions in both normal and pathological angiogenesis. The identification of such redox signaling and metabolic pathways is crucial to the gaining of better insights in endothelial biology and dysfunction. More importantly, these insights could be used to establish innovative therapeutic approaches for the treatment of those conditions where aberrant or excessive angiogenesis is the underlying cause of the disease itself. However, the formation, actions, key molecular interactions, and physiological and pathological relevance of redox signals in ECs remain unclear. Here, by using cutting-edge real-time redox imaging platforms, and innovative molecular and genetic approaches in different in vivo animal models, we will (1) reveal the working of redox signaling in EC in health and disease, (2) shed light on the novel role for the mevalonate metabolic pathway in angiogenesis and (3) provide solid evidence, that manipulation of endothelial redox and metabolic state by genetic alteration of the redox rheostat UBIAD1, is a valuable strategy by which to block pathological angiogenesis in vivo. The ultimate objective is to open the way for the development of innovative (cancer) therapeutic strategies and complement the existing ones based on genetic or pharmacological manipulation of redox rheostats to balance oxidative or reductive stress in angiogenic processes. The success of this project is built upon our major expertise in the field of angiogenesis in small vertebrate animal models as well as on the collaborations with leading laboratories that are active in research on the pre-clinical stages for angiogenesis-rel

1 999 827 €

Start date: 2016-07-01, End date: 2021-06-30