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Matallanas, David
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Matallanas, David
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Matallanas, David
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Now showing 1 - 10 of 41
- PublicationHidden Targets in RAF Signalling Pathways to Block Oncogenic RAS SignallingOncogenic RAS (Rat sarcoma) mutations drive more than half of human cancers, and RAS inhibition is the holy grail of oncology. Thirty years of relentless efforts and harsh disappointments have taught us about the intricacies of oncogenic RAS signalling that allow us to now get a pharmacological grip on this elusive protein. The inhibition of effector pathways, such as the RAF-MEK-ERK pathway, has largely proven disappointing. Thus far, most of these efforts were aimed at blocking the activation of ERK. Here, we discuss RAF-dependent pathways that are regulated through RAF functions independent of catalytic activity and their potential role as targets to block oncogenic RAS signalling. We focus on the now well documented roles of RAF kinase-independent functions in apoptosis, cell cycle progression and cell migration.
20 - PublicationHidden Targets in RAF Signalling Pathways to Block Oncogenic RAS SignallingOncogenic RAS (Rat sarcoma) mutations drive more than half of human cancers, and RAS inhibition is the holy grail of oncology. Thirty years of relentless efforts and harsh disappointments have taught us about the intricacies of oncogenic RAS signalling that allow us to now get a pharmacological grip on this elusive protein. The inhibition of effector pathways, such as the RAF-MEK-ERK pathway, has largely proven disappointing. Thus far, most of these efforts were aimed at blocking the activation of ERK. Here, we discuss RAF-dependent pathways that are regulated through RAF functions independent of catalytic activity and their potential role as targets to block oncogenic RAS signalling. We focus on the now well documented roles of RAF kinase-independent functions in apoptosis, cell cycle progression and cell migration.
27Scopus© Citations 14 - PublicationDissecting RAF Inhibitor Resistance by Structure-based Modeling Reveals Ways to Overcome Oncogenic RAS Signaling(Elsevier BV, 2018-08-22)
; ; ; ; ; ; ; ; ; Clinically used RAF inhibitors are ineffective in RAS-mutant tumors because they enhance homo- and heterodimerization of RAF kinases, leading to paradoxical activation of ERK signaling. Overcoming enhanced RAF dimerization and the resulting resistance is a challenge for drug design. Combining multiple inhibitors could be more effective, but it is unclear how the best combinations can be chosen. We built a next-generation mechanistic dynamic model to analyze combinations of structurally different RAF inhibitors, which can efficiently suppress MEK/ERK signaling. This rule-based model of the RAS/ERK pathway integrates thermodynamics and kinetics of drug-protein interactions, structural elements, post-translational modifications and cell mutational status as model rules to predict RAF inhibitor combinations for inhibiting ERK activity in oncogenic RAS and/or BRAFV600E backgrounds. Predicted synergistic inhibition of ERK signaling was corroborated by experiments in mutant NRAS, HRAS and BRAFV600E cells, and inhibition of oncogenic RAS signaling was associated with reduced cell proliferation and colony formation.Scopus© Citations 43 359 - PublicationAn Integrated Global Analysis of Compartmentalized HRAS Signaling(Elsevier, 2019-03-12)
; ; ; ; ; ; ; ; ; Modern omics technologies allow us to obtain global information on different types of biological networks. However, integrating these different types of analyses into a coherent framework for a comprehensive biological interpretation remains challenging. Here, we present a conceptual framework that integrates protein interaction, phosphoproteomics, and transcriptomics data. Applying this method to analyze HRAS signaling from different subcellular compartments shows that spatially defined networks contribute specific functions to HRAS signaling. Changes in HRAS protein interactions at different sites lead to different kinase activation patterns that differentially regulate gene transcription. HRAS-mediated signaling is the strongest from the cell membrane, but it regulates the largest number of genes from the endoplasmic reticulum. The integrated networks provide a topologically and functionally resolved view of HRAS signaling. They reveal distinct HRAS functions including the control of cell migration from the endoplasmic reticulum and TP53-dependent cell survival when signaling from the Golgi apparatus.Scopus© Citations 32 444 - PublicationIncreased extracellular vesicles mediate inflammatory signalling in cystic fibrosis(BMJ, 2020-05-15)
; ; ; ; ; ; ; Rationale Mutations in the cystic fibrosis transmembrane regulator (CFTR) gene form the basis of cystic fibrosis (CF). There remains an important knowledge gap in CF as to how diminished CFTR activity leads to the dominant inflammatory response within CF airways. Objectives To investigate if extracellular vesicles (EVs) contribute to inflammatory signalling in CF. Methods EVs released from CFBE41o-, CuFi-5, 16HBE14o- and NuLi-1 cells were characterised by nanoparticle tracking analysis (NTA). EVs isolated from bronchoalveolar lavage fluid (BALF) from 30 people with CF (PWCF) were analysed by NTA and mass spectrometry and compared with controls. Neutrophils were isolated from the blood of 8 PWCF to examine neutrophil migration in the presence of CFBE41o- EVs. Results A significantly higher level of EVs were released from CFBE41o- (p<0.0001) and CuFi-5 (p=0.0209) relative to control cell lines. A significantly higher level of EVs were detected in BALF of PWCF, in three different age groups relative to controls (p=0.01, 0.001, 0.002). A significantly lower level of EVs were released from CFBE41o- (p<0.001) and CuFi-5 (p=0.0002) cell lines treated with CFTR modulators. Significant changes in the protein expression of 126 unique proteins was determined in EVs obtained from the BALF of PWCF of different age groups (p<0.001-0.05). A significant increase in chemotaxis of neutrophils derived from PWCF was observed in the presence of CFBE41o EVs (p=0.0024) compared with controls. Conclusion This study demonstrates that EVs are produced in CF airway cells, have differential protein expression at different ages and drive neutrophil recruitment in CF.18Scopus© Citations 17 - PublicationBAX and SMAC regulate bistable properties of the apoptotic caspase system(Springer Nature, 2021-02-08)
; ; ; The initiation of apoptosis is a core mechanism in cellular biology by which organisms control the removal of damaged or unnecessary cells. The irreversible activation of caspases is essential for apoptosis, and mathematical models have demonstrated that the process is tightly regulated by positive feedback and a bistable switch. BAX and SMAC are often dysregulated in diseases such as cancer or neurodegeneration and are two key regulators that interact with the caspase system generating the apoptotic switch. Here we present a mathematical model of how BAX and SMAC control the apoptotic switch. Formulated as a system of ordinary differential equations, the model summarises experimental and computational evidence from the literature and incorporates the biochemical mechanisms of how BAX and SMAC interact with the components of the caspase system. Using simulations and bifurcation analysis, we find that both BAX and SMAC regulate the time-delay and activation threshold of the apoptotic switch. Interestingly, the model predicted that BAX (not SMAC) controls the amplitude of the apoptotic switch. Cell culture experiments using siRNA mediated BAX and SMAC knockdowns validated this model prediction. We further validated the model using data of the NCI-60 cell line panel using BAX protein expression as a cell-line specific parameter and show that model simulations correlated with the cellular response to DNA damaging drugs and established a defined threshold for caspase activation that could distinguish between sensitive and resistant melanoma cells. In summary, we present an experimentally validated dynamic model that summarises our current knowledge of how BAX and SMAC regulate the bistable properties of irreversible caspase activation during apoptosis.22Scopus© Citations 11 - PublicationQuantifying the Kinase Activities of MST1/2The functions of the kinases MST1 and MST2 rely heavily on their ability to phosphorylate and become phosphorylated themselves. Hence, it is important to precisely measure the kinase activities of both isoforms in a reproducible manner. Here, we describe in detail the protocol for an in-gel kinase assay for the quantification of the kinase activity of MST1/2, which involves immunoprecipitation of MST1/2 and the incorporation of radiolabeled phosphate from [γ-32P]-ATP into a substrate immobilized in a polyacrylamide gel. We also include a protocol for indirect measurement of MST1/2 activation status using immunoblotting.
285 - PublicationAll over the place: deciphering HRAS signaling from different subcellular compartmentsRAS (rat sarcoma virus oncogene homolog) oncogenes regulate fundamental biological processes through an ever-expanding signaling network. Using interaction proteomics, phosphoproteomics, transcriptomics, and integration of these datasets with a novel biostatistics approach, we have investigated Harvey-RAS (HRAS) signaling from different subcellular sites. The results reveal highly diversified signaling networks that regulate different aspects of HRAS functions.
19 - PublicationNew druggable targets in the Ras pathway?Ras proteins are key elements in the regulation of cellular proliferation, differentiation and survival. Mutational activation of Ras or of components of its effector pathways are detected in one-third of human cancers and are essential for the genesis and maintenance of the tumoral phenotype. Research efforts have been dedicated to the development of therapeutic agents that inhibit aberrant Ras signals and, subsequently, tumor progression. However, many of these initiatives have proven less successful than expected. This review summarizes the current status of developments in Ras research, the challenges that have arisen during preclinical and clinical stages, and how novel approaches to targeting Ras pathways have introduced new strategies toward the development of antitumoral agents that are alternative or complementary to those currently in use. These new approaches would be aimed at disrupting key protein-protein interactions that are essential for the conveyance of Ras aberrant signals or would be directed against new proteins recently demonstrated to be critical participants in Ras-regulated pathways.
311 - PublicationProteasomal down-regulation of the proapoptotic MST2 pathway contributes to BRAF inhibitor resistance in melanoma(Life Science Alliance, 2022-08-29)
; ; ; ; ; ; ; The RAS-RAF-MEK-ERK pathway is hyperactivated in most malignant melanomas, and mutations in BRAF or NRAS account for most of these cases. BRAF inhibitors (BRAFi) are highly efficient for treating patients with BRAFV600E mutations, but tumours frequently acquire resistance within a few months. Multiple resistance mechanisms have been identified, due to mutations or network adaptations that revive ERK signalling. We have previously shown that RAF proteins inhibit the MST2 proapoptotic pathway in a kinase-independent fashion. Here, we have investigated the role of the MST2 pathway in mediating resistance to BRAFi. We show that the BRAFV600E mutant protein, but not the wild-type BRAF protein, binds to MST2 inhibiting its proapoptotic signalling. Down-regulation of MST2 reduces BRAFi-induced apoptosis. In BRAFi-resistant cell lines, MST2 pathway proteins are down-regulated by ubiquitination and subsequent proteasomal degradation rendering cells refractory to MST2 pathway–induced apoptosis. Restoration of apoptosis can be achieved by increasing MST2 pathway protein expression using proteasome inhibitors. In summary, we show that the MST2 pathway plays a role in the acquisition of BRAFi resistance in melanoma.25Scopus© Citations 2