A Knock-In Mouse Model of Gastrointestinal Stromal Tumor Harboring Kit K641E

Memorial Sloan-Kettering Cancer Center, New York, New York, United States
Cancer Research (Impact Factor: 9.33). 09/2005; 65(15):6631-9. DOI: 10.1158/0008-5472.CAN-05-0891
Source: PubMed


A mouse model of gastrointestinal stromal tumor (GIST) has been developed by a knock-in gene targeting strategy, which introduced a Kit gene K641E mutation, originally identified in sporadic human GISTs and in the germ line of familial GIST syndrome patients. Homozygous and heterozygous Kit K641E mice develop gastrointestinal pathology with complete penetrance and all Kit K641E homozygotes die by age 30 weeks due to gastrointestinal obstruction by hyperplastic interstitial cells of Cajal (ICC) or GISTs. Heterozygous mice have less extensive ICC hyperplasia and smaller GISTs, suggesting a dose-response relationship between oncogenically activated Kit and ICC proliferation. Immunoprecipitation and Western blotting reveal GISTs to contain abundant phosphorylated/activated Kit. In addition to ICC hyperplasia and GISTs, homozygous Kit K641E mice exhibit loss-of-function Kit phenotypes, including white coat color, decreased numbers of dermal mast cells, and sterility, indicating that despite its oncogenic activity the mutant form cannot accomplish many activities of the wild-type gene. Kit K641E reproduces the pathology associated with the familial GIST syndrome and thus is an excellent model to study Kit pathway activation, ICC biology, GIST pathogenesis, and preclinical validations of GIST therapies and mechanisms of drug resistance.

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Available from: Yansong Gu, Apr 14, 2014
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    • "Predominant locations are the stomach (60% to -70%) and small intestine (25% to 30%), less common sites are the large bowel (up to 5%) and the omentum/mesentery (up to 5%) [7] [8]. Key event of pathogenesis in GIST are gain of function mutations in the genes encoding the receptor tyrosine kinase KIT (80% to 90%) or platelet derived growth factor receptor α (PDGFRα) (5% to 10%) [9] [10] [11]. "
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    ABSTRACT: Currently available data on prognostic implication of additional neoplasms in GIST miss comprehensive information on patient outcome with regard to overall or disease specific and disease free survival. Registry data of GIST patients with and without additional neoplasm were compared in retrospective case series. We investigated a total of 836 patients from the multi-center Ulmer GIST registry. Additionally, a second cohort encompassing 143 consecutively recruited patients of a single oncology center were analyzed. The frequency of additional malignant neoplasms in GIST patients was 31.9% and 42.0% in both cohorts with a mean follow-up time of 54 and 65 months (median 48 and 60 months), respectively. The spectrum of additional neoplasms in both cohorts encompasses gastrointestinal tumors (43.5%), uro-genital and breast cancers (34.1%), hematological malignancies (7.3%), skin cancer (7.3%) and others. Additional neoplasms have had a significant impact on patient outcome. The five year overall survival in GIST with additional malignant neoplasms (n = 267) was 62.8% compared to 83.4% in patients without other tumors (n = 569) (P < .001, HR=0.397, 95% CI: 0.298-0.530). Five-year disease specific survival was not different between both groups (90.8% versus 90.9%). 34.2% of all deaths (n = 66 of n = 193) were GIST-related. The presented data suggest a close association between the duration of follow-up and the rate of additional malignancies in GIST patients. Moreover the data indicate a strong impact of additional malignant neoplasms in GIST on patient outcome. A comprehensive follow-up strategy of GIST patients appears to be warranted. Copyright © 2014. Published by Elsevier Inc.
    Full-text · Article · Jan 2015 · Neoplasia (New York, N.Y.)
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    • "However, because tumor growth or responses to drug treatment observed in SQ xenograft models are often different from those observed in an orthotopic environment, two groups have developed transgenic mouse models of GIST. Rubin and colleagues identified a KITK641E mutation (exon 13) in sporadic human GISTs and in the germ line of familial GIST syndrome patients [24]. They then generated homozygous and heterozygous KITK641E transgenic mice that develop cecal GISTs with complete penetrance. "
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    ABSTRACT: Gastrointestinal stromal tumor (GIST) is the most common sarcoma and its treatment with imatinib has served as the paradigm for developing targeted anti-cancer therapies. Despite this success, imatinib-resistance has emerged as a major problem and therefore, the clinical efficacy of other drugs has been investigated. Unfortunately, most clinical trials have failed to identify efficacious drugs despite promising in vitro data and pathological responses in subcutaneous xenografts. We hypothesized that it was feasible to develop orthotopic patient-derived xenografts (PDXs) from resected GIST that could recapitulate the genetic heterogeneity and biology of the human disease. Fresh tumor tissue from three patients with pathologically confirmed GISTs was obtained immediately following tumor resection. Tumor fragments (4.2-mm3) were surgically xenografted into the liver, gastric wall, renal capsule, and pancreas of immunodeficient mice. Tumor growth was serially assessed with ultrasonography (US) every 3-4 weeks. Tumors were also evaluated with positron emission tomography (PET). Animals were sacrificed when they became moribund or their tumors reached a threshold size of 2500-mm3. Tumors were subsequently passaged, as well as immunohistochemically and histologically analyzed. Herein, we describe the first model for generating orthotopic GIST PDXs. We have successfully xenografted three unique KIT-mutated tumors into a total of 25 mice with an overall success rate of 84% (21/25). We serially followed tumor growth with US to describe the natural history of PDX growth. Successful PDXs resulted in 12 primary xenografts in NOD-scid gamma or NOD-scid mice while subsequent successful passages resulted in 9 tumors. At a median of 7.9 weeks (range 2.9-33.1 weeks), tumor size averaged 473+/-695-mm3 (median 199-mm3, range 12.6-2682.5-mm3) by US. Furthermore, tumor size on US within 14 days of death correlated with gross tumor size on necropsy. We also demonstrated that these tumors are FDG-avid on PET imaging, while immunohistochemically and histologically the PDXs resembled the primary tumors. We report the first orthotopic model of human GIST using patient-derived tumor tissue. This novel, reproducible in vivo model of human GIST may enhance the study of GIST biology, biomarkers, personalized cancer treatments, and provide a preclinical platform to evaluate new therapeutic agents for GIST.
    Full-text · Article · Feb 2014 · Journal of Translational Medicine
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    • "Mutant Kit oncoproteins also showed constitutive phosphorylation and kinase activity[5],[55]. More recently, studies using a knock-in approach to mimic clinically observed Kit mutations demonstrate that expression of the mutant receptor results in ICC hyperplasia and GIST formation in mice [56],[57]. Furthermore, families with heritable germline Kit mutations in exons 8, 11, 13, or 17 frequently developed ICC hyperplasia and multiple GISTs [53],[58]–[66]. These studies corroborate the link between the ICC and GIST and suggest that Kit mutation plays a significant and early role in GIST pathogenesis. "
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    ABSTRACT: Over the past 60 years, investigators of basic science, pathology, and clinical medicine have studied gastrointestinal stromal tumor (GIST) and made minor advances in patient care. Recent discoveries have led to an understanding of the biological role of KIT and platelet-derived growth factor receptor-α in GIST and the development of the tyrosine kinase inhibitor imatinib mesylate (Gleevec, formerly STI-571), one of the most exciting examples of targeted therapy to date. The success of targeted therapy in GIST has lead to new developments in our understanding of the medical and surgical management of the disease. Intense study of GIST may lead to new paradigms in the management of cancer.
    Full-text · Article · May 2011 · Chinese journal of cancer
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