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Query: EC:2.7.10.1 (
ERK
)
95,504
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Gastrointestinal stromal tumor (GIST), a form of soft-tissue sarcoma, is the most common noncarcinomatous tumor of the gastrointestinal tract. Despite its high incidence of recurrence, the malignant potential of GIST has been under-recognized. Advances in diagnostic technology since 2000 have led to increased diagnoses of GIST, suggesting that GIST is more common than previously suspected. Historically, the only treatment for GIST was surgical resection, but recent advances in the understanding of the pathogenesis of the disease have led to the development of a new treatment. A key factor in the growth and survival of cancerous GIST cells is the uncontrolled activation of a signaling enzyme known as
KIT
, a receptor tyrosine kinase, which becomes locked in an activated state. The abnormal signaling from the overactive
KIT
enzyme causes GIST cells to survive and proliferate uncontrollably.
Imatinib mesylate
is an oral drug designed to inhibit the kinase enzyme activity of
KIT
. Imatinib has been proven in several clinical trials to be effective against GIST and is currently the firstline medical therapy for malignant metastatic or recurrent GIST. Imatinib is administered as an outpatient oral drug and warrants nursing management with particular attention to potential side effects, significant drug interactions, monitoring, and patient education. This article--based on published trials and clinical experience--summarizes the nursing implications, clinical efficacy, and safety of imatinib as an effective and rationally targeted treatment for GIST.
...
PMID:Nursing implications of imatinib as molecularly targeted therapy for gastrointestinal stromal tumors. 1585 60
Over the past 5 years, small molecule tyrosine kinase inhibitors have been successfully introduced as new cancer therapeutics. The pioneering work with the ABL inhibitor imatinib (
Glivec
,
Gleevec
) was rapidly extended to other types of leukemias as well as solid tumors, which stimulated the development of a variety of new tyrosine kinase inhibitors. Unfortunately, oncogenic tyrosine kinases seem to have little problem to develop resistance to these inhibitors, and there is good evidence that this is not limited to imatinib, but also occurs with other inhibitors, such as
FLT3
and
EGFR
inhibitors. Based on studies with imatinib, mutation and amplification of the target kinase seem to be the most important mechanisms for the development of resistance, but these mechanisms alone cannot explain all cases of resistance. A better understanding of the resistance mechanisms will be required to design improved treatment strategies in the future. In this review, we summarize the current insights in the different mechanisms of resistance to small molecule tyrosine kinase inhibitors, and discuss future improvements that might limit or even overcome resistance.
...
PMID:Resistance to tyrosine kinase inhibitors: calling on extra forces. 1586 1
Continuous administration of the direct-reacting carcinogen N-methyl-N'-nitro-N-nitrosoguanidine reportedly produces not only adenocarcinoma in rats, but also mesenchymal tumors. A large number of tumors diagnosed as gastrointestinal smooth muscle tumors actually represent gastrointestinal stromal tumors (GISTs) in human cases. We have induced mesenchymal tumors by duodenal reflux in rats. To clarify the differentiation of these mesenchymal tumors, immunohistochemical investigations were undertaken. In addition, the first culture model of GIST-DR derived from GIST induced by duodenal reflux was established. GIST-DR cells, both in vitro and in vivo, were strongly immunopositive for both
KIT
and CD34, and STI571 (
Imatinib mesylate
) blocked the proliferation of this cell line. The present results suggest that duodenal reflux plays a role in the histogenesis of GIST.
...
PMID:Induction of gastric GIST in rat and establishment of GIST cell line. 1588 27
Receptor and non-receptor tyrosine kinases (TKs) have emerged as clinically useful drug target molecules for treating gastrointestinal cancer.
Imatinib mesilate
(STI-571,
Gleevec
(TM)), an inhibitior of bcr-abl TK, which was primarily designed to treat chronic myeloid leukemia is also an inhibitor of c-kit receptor TK, and is currently the drug of choice for the therapy of metastatic gastrointestinal stromal tumors (GISTs), which frequently express constitutively activated forms of the c-kit-receptor. The epidermal growth factor receptor (EGFR), which is involved in cell proliferation, metastasis and angiogenesis, is another important target. The two main classes of EGFR inhibitors are the TK inhibitors and monoclonal antibodies. Gefitinib (ZD1839, Iressa(TM)) has been on trial for esophageal and colorectal cancer (CRC) and erlotinib (OSI-774, Tarceva(TM)) on trial for esophageal, colorectal, hepatocellular, and biliary carcinoma. In addition, erlotinib has been evaluated in a Phase III study for the treatment of pancreatic cancer. Cetuximab (IMC-C225, Erbitux(TM)), a monoclonal EGFR antibody, has been FDA approved for the therapy of irinotecan resistant colorectal cancer and has been tested for pancreatic cancer. Vascular endothelial growth factor (VEGF) and its receptor (VEGFR) are critical regulators of tumor angiogenesis. Bevacizumab (Avastin(TM)), a monoclonal antibody against VEGF, was efficient in two randomized clinical trials investigating the treatment of metastatic colorectal cancer. It is also currently investigated for the therapy of pancreatic cancer in combination with gemcitabine. Other promising new drugs currently under preclinical and clinical evaluation, are
VEGFR2
inhibitor PTK787/ZK 222584, thalidomide, farnesyl transferase inhibitor R115777 (tipifarnib, Zarnestra(TM)), matrix metalloproteinase inhibitors, proteasome inhibitor bortezomib (Velcade(TM)), mammalian target of rapamycin (mTOR) inhibitors, cyclooxygenase-2 (COX-2) inhibitors, platelet derived growth factor receptor (PDGF-R) inhibitors, protein kinase C (PKC) inhibitors, mitogen-activated protein kinase kinase (MEK) 1/2 inhibitors, Rous sarcoma virus transforming oncogene (SRC) kinase inhibitors, histondeacetylase (HDAC) inhibitors, small hypoxia-inducible factor (HIF) inhibitors, aurora kinase inhibitors, hedgehog inhibitors, and TGF-beta signalling inhibitors.
...
PMID:Molecularly targeted therapy for gastrointestinal cancer. 1589 18
The authors report a unique case of an intra-abdominal, epithelioid mesenchymal tumor that had an activating mutation of
PDGFRA
and a strong
PDGFRA
immunoreactivity but lacked both c-kit mutation and c-kit protein (CD117) expression. IHC study showed that the tumor cells were diffusely and strongly positive for
PDGFRA
, vimentin, CD34, and Bcl-2 but completely negative for CD117 as well as for muscle, epithelial, endothelial, endocrine, mesothelial, neural, and melanocytic cell markers. Molecular study revealed a mutation at the juxtamembrane domain of exon 12 in
PDGFRA
gene with GTC to GAC transition at codon 561 (V561D), as shown in the previous mutational studies on gastrointestinal stromal tumor (GIST). This case likely represents an example of GIST with
PDGFRA
activating mutation and
PDGFRA
immunoreactivity without CD117 positivity, which has not been documented in the literature. STI 571 (imatinib mesylate [
Gleevec
]) might be an effective therapy in this case, since
Gleevec
targets both
PDGFRA
and c-kit oncoproteins.
...
PMID:Epithelioid gastrointestinal stromal tumor with PDGFRA activating mutation and immunoreactivity. 1589 28
Androgen-deprivation therapy, usually with combined androgen blockade, is standard initial treatment for advanced prostate cancer. With failure of initial treatment, as indicated by rising prostate-specific antigen (PSA) levels, second-line hormonal therapy is usually instituted. Over the past several years, it has become increasingly clear that systemic chemotherapy has an important role in hormone-refractory disease. Phase II trials have demonstrated high PSA and measurable disease response rates with taxane single-agent and combination treatments. One recent phase III trial showed that docetaxel (Taxotere)/ estramustine (Emcyt) significantly improved overall survival, progression-free survival, and PSA response rate compared with mitoxantrone (Novantrone) plus prednisone. Another phase III trial demonstrated that docetaxel given every 3 weeks plus prednisone significantly improved overall survival, PSA response rate, pain relief response rate, and quality of life compared with mitoxantrone and prednisone. On the basis of these findings, every-3-week docetaxel plus prednisone is now considered standard first-line therapy for metastatic hormone-refractory disease. There is considerable optimism that treatment can be further improved. Studies of taxane combinations with bevacizumab (Avastin), thalidomide (Thalomid), bortezomib (Velcade), antisense Bcl-2 oligonucleotide, mTOR inhibitors, epidermal growth factor receptor inhibitors, and
KDR
inhibitors are under way. Randomized phase III trials in progress or planned are examining docetaxel in combination with imatinib mesylate (
Gleevec
) or calcitriol and docetaxel/prednisone in combination with bevacizumab and an antisense clusterin compound. Other promising systemic agents include epothilones and atrasentan, and promising vaccines include Provenge, GVAX, and Prostvac.
...
PMID:Recent progress in management of advanced prostate cancer. 1594 43
Until recently, there were few effective therapeutic options for patients with gastrointestinal stromal tumors (GISTs). Most patients undergoing even potentially curative resection for early-stage disease recurred if followed for a sufficiently long period, and treatment of advanced tumors with systemic chemotherapy was ineffective.
Imatinib mesylate
, a molecularly targeted agent that inhibits the
KIT
receptor tyrosine kinase, has now been demonstrated to be highly effective at inducing objective responses in GIST patients, and it improves overall survival. In locoregional disease, ongoing studies are assessing the use of imatinib pre-or postsurgery. In addition, other agents possessing activity against a variety of molecular targets are being tested in advanced disease. Questions remain about the optimal dose of imatinib, whether to continue drug in the setting of progressive disease, and how best to prevent or overcome resistance.
...
PMID:State-of-the art therapy for gastrointestinal stromal tumors. 1594 12
Conventional chemotherapeutic drugs are ineffective in treatment of gastrointestinal stromal tumors (GISTs). Imatinib (STI571,
Gleevec
,
Glivec
; Novartis Pharmaceuticals, East Hanover, NJ), a selective inhibitor of
KIT
, ABL, BCR-ABL,
PDGFRA
, and
PDGFRB
, represents a new paradigm of targeted cancer therapy and has revolutionized the treatment of patients with chronic myelogenous leukemia and GISTs. Unfortunately, imatinib resistance has emerged. The reported mechanism of imatinib resistance in GISTs involves missense mutation in the kinase domain of
KIT
, including Thr670Ile, Tyr823Asp, and Val654Ala. The established mechanisms and potential mechanisms of imatinib resistance in GISTs, the imaging studies indicative of early development of imatinib resistance, and the management of imatinib-resistant GISTs are discussed.
...
PMID:Imatinib resistance in gastrointestinal stromal tumors. 1594 89
Idiopathic hypereosinophilic syndrome is characterised by chronic hypereosinophilia leading to tissue damage, and after exclusion of reactive eosinophilia. Until recently no specific or efficient therapeutic was available. In 2003, a recurrent interstitial deletion 4q12 leading to the fusion of the FIP1L1 and
PDGFRA
genes was detected in hypereosinophilic syndromes. The resulting protein has constitutive tyrosine kinase activity which explains clinical and cytological remission of hypereosinophilic syndrome after treatment by a specific tyrosine kinase inhibitor, imatinib mesylate or
Glivec
, usually used in chronic myeloid leukaemia. Here we report a patient with hypereosinophilic syndrome associated to peculiar morphology of neutrophilic series and the 4q12 deletion. He presented clinical and haematological remission since the introduction of imatinib mesylate therapy.
...
PMID:[Idiopathic hypereosinophilic syndrome: toward a new molecular-targeted therapy and a new cytomorphological and molecular definition]. 1595 Dec 64
Synovial sarcoma is a soft tissue malignancy with a poor prognosis; many patients will die from this disease within 10 years of diagnosis, despite treatment. Gene expression profiling and immunohistochemistry studies have identified oncogenes that are highly expressed in synovial sarcoma. Included in this group are receptor tyrosine kinases such as epidermal growth factor receptor, insulin-like growth factor receptor 1, fibroblast growth factor receptor 3,
KIT
, and
HER2
. Inhibitors of these growth-promoting receptors are likely to inhibit proliferation of synovial sarcoma; however, the effect of receptor tyrosine kinase inhibitors on synovial sarcoma is largely unknown. We assessed the ability of the following receptor tyrosine kinase inhibitors to halt proliferation and induce apoptosis in synovial sarcoma monolayer and three dimensional spheroid in vitro models: gefitinib (Iressa), NVP-AEW541, imatinib mesylate (
Gleevec
), SU5402, PRO-001, trastuzumab (Herceptin), and 17-allylamino-17-demethoxygeldanamycin (17-AAG). Gefitinib, NVP-AEW541, and imatinib inhibited proliferation only at relatively high concentrations, which are not clinically applicable. 17-AAG, which destabilizes multiple receptor tyrosine kinases and other oncoproteins through heat shock protein 90 inhibition, prevented proliferation and induced apoptosis in synovial sarcoma monolayer models at concentrations achievable in human serum. 17-AAG treatment was also associated with receptor tyrosine kinase degradation and induction of apoptosis in synovial sarcoma spheroid models. 17-AAG was more effective than doxorubicin, particularly in the spheroid models. Here we provide in vitro evidence that 17-AAG, a clinically applicable drug with known pharmacology and limited toxicity, inhibits synovial sarcoma proliferation by inducing apoptosis, and thus has potential as a systemic therapy for this disease.
...
PMID:Hsp90 inhibitor 17-allylamino-17-demethoxygeldanamycin prevents synovial sarcoma proliferation via apoptosis in in vitro models. 1606 82
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