ERC FUNDED PROJECTS

My objective is to understand the physiologic and medical importance of the posttranslational processing of CAAX proteins (e.g., K-RAS and prelamin A) and to define the suitability of the CAAX protein processing enzymes as therapeutic targets for the treatment of cancer and progeria. CAAX proteins undergo three posttranslational processing steps at a carboxyl-terminal CAAX motif. These processing steps, which are mediated by four different enzymes (FTase, GGTase-I, RCE1, and ICMT), increase the hydrophobicity of the carboxyl terminus of the protein and thereby facilitate interactions with membrane surfaces. Somatic mutations in K-RAS deregulate cell growth and are etiologically involved in the pathogenesis of many forms of cancer. A mutation in prelamin A causes Hutchinson-Gilford progeria syndrome—a pediatric progeroid syndrome associated with misshaped cell nuclei and a host of aging-like disease phenotypes. One strategy to render the mutant K-RAS and prelamin A less harmful is to interfere with their ability to bind to membrane surfaces (e.g., the plasma membrane and the nuclear envelope). This could be accomplished by inhibiting the enzymes that modify the CAAX motif. My Specific Aims are: (1) To define the suitability of the CAAX processing enzymes as therapeutic targets in the treatment of K-RAS-induced lung cancer and leukemia; and (2) To test the hypothesis that inactivation of FTase or ICMT will ameliorate disease phenotypes of progeria. I have developed genetic strategies to produce lung cancer or leukemia in mice by activating an oncogenic K-RAS and simultaneously inactivating different CAAX processing enzymes. I will also inactivate several CAAX processing enzymes in mice with progeria—both before the emergence of phenotypes and after the development of advanced disease phenotypes. These experiments should reveal whether the absence of the different CAAX processing enzymes affects the onset, progression, or regression of cancer and progeria.

1 689 600 €

Start date: 2008-06-01, End date: 2013-05-31

Most colorectal cancers (CRCs) are initiated by activating mutations in components of the Wnt signalling pathway. Physiological Wnt signals are required for the specification and maintenance of the stem and progenitor cell compartments of the intestinal crypts. We demonstrated that early colorectal lesions exhibit a constitutive Wnt target gene programme, which is very similar to that of normal intestinal stem and progenitor cells. We originally proposed that colorectal adenomas behave as clusters of intestinal cells locked into a constitutive crypt progenitor phenotype. Given the prevalence of Wnt signalling mutations in CRC, an outstanding endeavour is the characterization of the similarities and differences in the instructions dictated by beta-catenin and Tcf to normal intestinal cells vs. CRC cells. Here, we propose to systematically compare and catalogue the beta-catenin/Tcf genetic programmes in intestinal progenitor/stem cells, intestinal adenomas and late CRCs. Transcriptomic analysis of isolated normal progenitor cells and tumor cell populations combined with bioinformatic analysis of gene regulatory networks will allow us to workout the hierarchical interactions downstream of beta-catenin and Tcf. Moreover, functional analysis of key beta-catenin/Tcf target genes using genetically modified mice models will help us to pinpoint which Wnt-controlled functions are essential for tumor maintenance and progression in vivo. Moreover, we seek to understand the tumor suppressor role of EphB2 and EphB3 receptors, two beta-catenin/Tcf target genes in normal crypts and benign colorectal adenomas, that block cancer progression by compartmentalizing tumor cells at the onset of CRC. Overall, our results will shed light on the relationship between stem/progenitor cells and cancer and hold potential for the future development of both therapeutic and diagnostic tools.

1 602 817 €

Start date: 2008-09-01, End date: 2013-08-31

Glioma is the most common and aggressive tumour of the brain and its most malignant form, glioblastoma multiforme, is nowadays virtually not curable. Very little is known about glioma genesis and progression at the molecular level and not much progress has been achieved in the treatment of this disease during the last years. The understanding of the molecular mechanisms involved in the biology of glioma is essential for the development of successful and rational therapeutic strategies. Our project aims to: 1- Study the role of the TGF-beta, Shh, Notch, and Wnt signal transduction pathways in glioma. These pathways have been implicated in glioma but still not much is known about their specific mechanisms of action. 2- Study of a cell population within the tumour mass that has stem-cell-like characteristics, the glioma stem cells, and how the four mentioned pathways regulate their biology. 3- Study the role of a transcription factor, FoxG1, that has an important oncogenic role in some gliomas and that it is regulated by the four mentioned pathways interconnecting some of them. Our approach will be based on a tight collaboration with clinical researchers of our hospital and the study of patient-derived tumours. We will analyse human biopsies, generate primary cultures of human tumour cells, isolate the stem-cell-like population of patient-derived gliomas and generate mouse models for glioma based on the orthotopical inoculation of human glioma stem cells in the mouse brain to generate tumours with the same characteristics as the original human tumour. In addition, we will also study genetically modified mouse models and established cell lines. We expect that our results will help understand the biology of glioma and cancer, and we aspire to translate our discoveries to a more clinical ambit identifying molecular markers of diagnosis and prognosis, markers of response to therapies, and unveil new therapeutic targets against this deadly disease.

1 566 000 €

Start date: 2008-08-01, End date: 2014-07-31

Endothelial cells (EC) lining the inside of blood/lymphatic vessels in different organs show significant heterogeneity caused by cell-intrinsic and -extrinsic factors. While intrinsic properties are preserved in vitro, EC-extrinsic characteristics are lost upon isolation from the in vivo context. Thus, getting a grasp on EC diversity requires an approach that integrates EC-intrinsic and -extrinsic cues. EC heterogeneity likely forms the basis of vessel-type restricted disorders and may explain the side effects and limited success of ‘broad-spectrum’ (anti-)angiogenic therapies. Also, EC progenitor-based revascularization studies have not asked whether cells acquire the desired EC phenotype once engrafted in diseased tissue where appropriate environmental cues are lacking. Unraveling mechanisms of EC heterogeneity should allow designing tailor-made therapies, which remains the main challenge in curing vessel-related disease. This research program proposes to use an unprecedented integrated in vitro/in vivo multi-disciplinary approach based on stem/progenitor cells and small animal models to: (i) expand our knowledge of EC diversity; (ii) exploit that knowledge to design specialized vascular therapies for (lymph)vascular disorders. In phase 1, gene-profiles (‘blueprints’) will be obtained by micro-array on EC isolated from various organs and macrovessels of different species with (intrinsic blueprint) or without (extrinsic blueprint) further culture. In phase 2, (co-)culture techniques that simulate the in vivo context will be applied to generate EC with the desired blueprint and appropriate function/morphology, by EC differentiation from adult stem cells. In phase 3, information obtained from phase 1/2 will be validated in vivo by (i) testing the expression profile of selected blueprint-genes, (ii) by morpholino knock-down of these genes in zebrafish, (iii) by transplanting stem cells, pre-specialized or not, into models of vascular bed or organ-specific disorders.

1 616 719 €

Start date: 2008-10-01, End date: 2013-09-30