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Project description:Purpose: Management of gastrointestinal stromal tumor (GIST) has been revolutionized by the identification of activating mutations in KIT and PDGFRA and the clinical application of receptor tyrosine kinase (RTK) inhibitors in the advanced disease setting. Stratification of GIST into molecularly defined subsets provides insight into clinical behavior and response to approved targeted therapies. Although these RTK inhibitors are effective in the majority of GIST, resistance to these agents remains a significant clinical obstacle. Development of effective treatment strategies for refractory GIST requires identification of novel targets to provide additional therapeutic options. Global kinome profiling has the potential to identify critical signaling networks and reveal protein kinases that are essential in GIST. Experimental Design: Using Multiplexed Inhibitor Beads and Mass Spectrometry paired with a super-SILAC kinome standard, we explored the majority of the kinome in GIST specimens from three GIST subtypes (KIT-mutant, PDGFRA-mutant and succinate dehydrogenase-deficient GIST) to identify novel kinase targets. In vitro and in vivo studies were performed to evaluate the utility of targeting the identified kinases in GIST. Results: Kinome profiling revealed distinct signatures in three GIST subtypes. PDGFRA-mutant GIST had elevated tumor associated macrophage (TAM) kinases and immunohistochemical analysis confirmed increased TAMs present in these tumors. Kinome profiling with loss-of-function assays revealed a significant role for G2-M tyrosine kinase, Wee1, in GIST survival. In vitro and in vivo studies revealed significant efficacy of MK-1775 (Wee1 inhibitor) in combination with avapritinib in both KIT and PDGFRA-mutant GIST cell lines, as well as notable efficacy of MK-1775 as a single agent in the PDGFRA-mutant line. Conclusions: These studies provide strong preclinical justification for the use of MK-1775 in GIST.
2021-09-09 | PXD020720 | Pride
Project description:Mutations in KIT proto-oncogene receptor tyrosine kinase (KIT) or platelet derived growth factor receptor alpha (PDGFRA) are responsible for more than 85% of the gastrointestinal stromal tumors (GIST). The introduction of imatinib in the therapy scheme of GIST revolutionized the patient outcome. Unfortunately, the therapy allows a disease stabilization rather than curation. Resistance to the inhibitor arises in most cases within the two first years of therapy. The identification of new targets to treat GIST is now essential. We propose a thorough investigation of the activating mechanisms derived from the main PDGFRA and KIT mutants encountered in the GIST landscape. We identified striking differences among the different KIT mutants while PDGFRA mutants delivered a very uniform picture. KIT Exon 11 deletion mutant exhibited the highest intrinsic kinase activity and all KIT mutants were, in addition to their constitutive activation, responsive to stem cell factor (SCF) stimulation. This highlights the importance of evaluating the SCF expression profile in GIST patients. In contrast, PDGFRA mutants were not responsive to their ligand, PDGFAA, and displayed a very high intrinsic kinase activity. At the transcriptomic level, the mitogen-activated protein kinase (MAPK) pathway was established as the most prominent activated pathway, commonly up-regulated by all PDGFRA and KIT mutants. Inhibition of this pathway using the MEK inhibitor PD0325901 reduced the proliferation of GIST primary cells in the nanomolar range. This demonstrates the high value of MEK inhibitors for combination therapy in GIST treatment. This experiment contains expression data from HEK-293 cells expressing wild-type and mutant KIT. The mutants included in the study correspond to the main mutations found in GIST, mainly KIT Ex9 exhibits a duplication of AY502-503 and KIT Ex11 a deletion of residues 553 to 557.
2017-07-05 | E-MTAB-4548 | biostudies-arrayexpress
Project description:GIST is considered to invariably arise through gain-of-function KIT or PDGFRA mutation of the interstitial cells of Cajal (ICC). However, the genetic basis of the malignant progression of GIST is poorly understood. We analysed the expression levels of 54,613 probe sets in 32 surgical samples of untreated GIST of the stomach and small intestine with GeneChip Human Genome U133 Plus 2.0 arrays. Keywords: gene expression array-based, count
2008-06-15 | GSE8167 | GEO
Project description:A growing body of literature has consolidated the important role of miRNA in a variety of biological processes, in cancer development, acting both as oncogenes and tumor suppressor genes, and in their ability to distinguish tumors according to their diagnostic and prognostic properties.To date, little is known, however, about differences in miRNA expression between KIT/PDGFRA mutant and KIT/PDGFRA WT GIST.
2016-10-03 | E-MTAB-4490 | biostudies-arrayexpress
Project description:Gastrointestinal stomal tumors (GIST) are mainly characterised by the presence of activating mutations in either of the two receptor tyrosine kinases c-KIT and Platelet-derived growth factor receptor-a (PDGFRa). Most mechanistic studies dealing with GIST mutations have focused on c-KIT and far less is known about the signalling characteristics of the mutated PDGFRa proteins. Comparative studies of the signal transduction capacities of different mutant proteins cannot be performed in patient cells due to the patient specific background which may influence the signalling behaviour of the investigated mutants. In addition, the lack of a real wild-type signalling control (PDGFRa-WT) hampers comparisons of the signalling of wild-type and mutant proteins. Therefore, we stably and inducibly expressed different PDGFRa mutants as well as wild-type PDGFRa on an isogenic background in 293T cells in order to study the signalling capacities and corresponding transcriptional responses of the different proteins. We found that the constitutive signalling via the oncogenic PDGFRa mutants favours a mislocalisation of the receptors and that this modifies the signalling characteristics of the mutated receptors. We show that signalling via the oncogenic PDGFRa mutants is not solely characterised by a constitutive activation of the conventional PDGFRa signalling pathways.
2015-11-11 | E-MTAB-2101 | biostudies-arrayexpress
Project description:In addition to KIT and PDGFRA mutations, sequential accumulation of other genetic events is involved in the development and progression of gastrointestinal stromal tumors (GISTs). Until recently, the significance of these other alterations has not been thoroughly investigated. The combination of gene expression profiling and high-resolution genomic copy number analysis offers a detailed molecular portrait of GISTs, providing an essential comprehensive knowledge necessary to guide the discovery of novel target genes involved in tumor development and progression. Fresh tissue specimens from 25 patients with GIST were collected and high-resolution genomic copy number analyses were performed using Affymetrix SNP array 6.0. GIST tumor samples from mutated (KIT or PDGFRA) or Wild Type patients were labeled for hybridization on Affymetrix microarrays. Copy number analysis of Affymetrix SNP6.0 arrays was performed for 25 GIST samples, then compared to gene expression data.
2010-08-27 | E-GEOD-20709 | biostudies-arrayexpress
Project description:Activating mutations in either KIT or PDGFRA are present in approximately 90% of gastrointestinal stromal tumors (GISTs). Although treatment with the KIT and PDGFR inhibitor imatinib can control advanced disease in about 80% of GIST patients, the beneficial effect is not durable. Here, we report that ligands from the FGF family reduced the effectiveness of imatinib in GIST cells, and FGF2 and FGFR1 are highly expressed in all primary GIST samples examined. The combination of KIT and FGFR inhibition showed increased growth inhibition in imatinib-sensitive GIST cell lines in the presence or absence of added FGF2 in vitro, and delayed tumor regrowth in vivo. In addition, inhibition of mitogen-activated protein kinase (MAPK) signaling by imatinib was not sustained in GIST cells. An extracellular signal-regulated kinase (ERK) rebound occurred through activation of FGF signaling, and was repressed by FGFR1 inhibition. Downregultation of Sprouty proteins played a role in the imatinib-induced feedback activation of FGF signaling in GIST cells. We used micorarrays to quantify the gene expression levels in GIST cell lines.
2015-01-08 | GSE64762 | GEO
Project description:In contrast to the paucity of clinic GIST (Gastrointestinal stromal tumor; 0.0014 % happening rate), there is a more than twenty thousand times higher rate for miniGISTs, about ~30% of human population could be identified to have miniGISTs. Exploring the molecular differences between miniGISTs and overt GISTs will help us to understand the transformation mechanisms along with GIST progression, but C-kit and PDGFRA mutations analysis failed to identify the differences between these two groups. Conclusion: miniGISTs have significant distinct gene expression profile with overt GISTs by both unsupervised and supervised analysis. Our finding indicated that c-kit and DOG1 expression are the very early events in the genesis of miniGIST and overt GIST, and miniGIST is a molecular distinct group with overt GIST.
2014-12-25 | GSE52666 | GEO
Project description:Activating mutations in the KIT or PDGFRA receptor tyrosine kinases are hallmarks of gastrointestinal stromal tumor (GIST). The biological underpinnings of recurrence following resection or disease progression beyond kinase mutation are poorly understood. Utilizing chromatin immunoprecipitation with sequencing (ChIP-seq) of tumor samples and cell lines, we describe the enhancer landscape of GIST, highlighting genes that reinforce and extend our understanding of these neoplasms. A group of core transcription factors can be distinguished from others unique to localized and metastatic disease. The transcription factor HAND1 emerges in metastatic disease, binds to established GIST-associated enhancers and is required for GIST cell proliferation and KIT gene expression. The pattern of transcription factor expression in primary tumors is predictive of metastasis-free survival in GIST patients. These results provide insight into the enhancer landscape and transcription factor network underlying GIST, and define a new strategy for predicting clinical behavior of this disease.
2018-05-21 | GSE95863 | GEO
Project description:Activating mutations in the KIT or PDGFRA receptor tyrosine kinases are hallmarks of gastrointestinal stromal tumor (GIST). The biological underpinnings of recurrence following resection or disease progression beyond kinase mutation are poorly understood. Utilizing chromatin immunoprecipitation with sequencing (ChIP-seq) of tumor samples and cell lines, we describe the enhancer landscape of GIST, highlighting genes that reinforce and extend our understanding of these neoplasms. A group of core transcription factors can be distinguished from others unique to localized and metastatic disease. The transcription factor HAND1 emerges in metastatic disease, binds to established GIST-associated enhancers and is required for GIST cell proliferation and KIT gene expression. The pattern of transcription factor expression in primary tumors is predictive of metastasis-free survival in GIST patients. These results provide insight into the enhancer landscape and transcription factor network underlying GIST, and define a new strategy for predicting clinical behavior of this disease.
2018-05-21 | GSE95862 | GEO