Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P42345 (mTOR)
 26,049 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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.
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PMID:Molecularly targeted therapy for gastrointestinal cancer. 1589 18

Identification of the key roles of protein kinases in signaling pathways leading to development of cancer has caused pharmacological interest to concentrate extensively on targeted therapies as a more specific and effective way for blockade of cancer progression. This review will mainly focus on inhibitors targeting these key components of cellular signaling by employing a technology-based point of view with respect to ATP- and non-ATP-competitive small molecule inhibitors and monoclonal antibodies of selected protein kinases, particularly, mammalian target of rapamycin (mTOR), BCR-ABL, MEK, p38 MAPK, EGFR PDGFR, VEGFR, HER2 and Raf. Inhibitors of the heat shock protein Hsp90 are also included in a separate section, as this protein plays an essential role for the maturation/proper activation of cancer-related protein kinases. In the following review, the molecular details of the mode of action of these inhibitors as well as the emergence of drug resistance encountered in several cases are discussed in light of the structural, molecular and clinical studies conducted so far.
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PMID:Protein kinases as drug targets in cancer. 1710 May 68

Angiogenesis is an important hallmark of RCC, reflected in the natural history, Histology, genetics and now therapeutics of this disease. Clearly, the pro-angiogenic growth factor VEGF is a functional drug target in RCC and many strategies to inhibit this biology have shown clinical benefit. Multi-targeted TKI that inhibit VEGFRs have been approved by the FDA as standard treatment for advanced RCC. Pharmacodynamyc studies suggest that these agents and others also have anti-angiogenic effects. Currently, studies combining VEGFR-targeted strategies with other anti-angiogenic agents, including anti-VEGF antibodies, IFN or mTOR inhibitors, are underway. However, to what extent the clinical benefit of anti-angiogenic strategies in RCC can be built upon is unknown.
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PMID:Anti-angiogenic therapy in renal cell cancer. 1744 27

Renal cell carcinoma (RCC) is a highly vascular tumor in which a growing understanding of disease biology has been translated into clinically active systemic therapies. The most clinically developed targeted therapies in advanced RCC are those that target the vascular endothelial growth factor (VEGF) ligand or receptor (VEGFR) and therapy directed against the mammalian target of rapamycin (mTOR). Sutent and sorafenib are orally available inhibitors of the VEGFR and platelet derived growth factor receptor (PDGFR). Temsirolimus is an mTOR inhibitor that leads to G1 cell cycle arrest and may affect VEGF production. This article briefly describes the biological pathways involved in the development of RCC and the results of clinical trials using targeted therapy in metastatic RCC.
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PMID:The role of targeted therapy in metastatic renal cell carcinoma. 1761 63

Understanding the alterations in cellular protein interactions and their relations to genetic mutations that cause renal cell carcinoma (RCC) provides a unique opportunity for the development of disease-specific therapy for patients with advanced forms of this disease. There is substantial evidence of an association between mutation on von Hippel-Lindau (VHL) gene and the earliest stages of tumorigenesis of RCC. The main consequence of VHL loss is the upregulation of downstream proangiogenic factors leading to highly vascular tumors. Overexpression of hypoxia inducible factor (HIF) is also caused by the mammalian target of rapamycin (mTOR), a key component of signaling pathways inside the cell, involved in cell proliferation. The inhibition of proangiogenic factors and mTOR was the main idea behind the development of new targeted agents in advanced RCC. Since December 2005, 3 targeted agents have been approved by the U.S. Food and Drug Administration (FDA) for the treatment of advanced RCC: sorafenib, sunitinib and temsirolimus. Sorafenib and sunitinib are synthetic, orally active agents shown to directly inhibit vascular endothelial growth factor receptors -2 and -3 (VEGFR-2, VEGFR-3) and platelet-derived growth factor receptor beta (PDGFR-beta), while temsirolimus is an mTOR inhibitor. Recent clinical studies form the basis for new guidelines for the treatment of advanced RCC: sorafenib should be used as a second-line treatment, sunitinib as the first-line therapy for good and intermediate-risk patients, and temsirolimus should be considered as first-line treatment for poor-risk patients. Future approaches to targeted therapy should focus on optimizing the use of current active drugs, exploring their combinations or investigating their sequential use. In addition, it is important to define the mechanisms of resistance on their use and to further investigate biomarkers and enhance treatment efficacy for the individual patients. The development of these targeted therapies represents an exciting step forward in the treatment of advanced RCC.
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PMID:Sunitinib, sorafenib and mTOR inhibitors in renal cancer. 1793 73

Hepatocellular carcinoma (HCC) is characterized as a highly chemoresistant cancer with no effective systemic therapy. Despite surgical or locoregional therapies, prognosis remains poor because of high tumor recurrence or tumor progression, and currently there are no well-established effective adjuvant therapies. The molecular biology of carcinogenesis and tumor progression of HCC has been increasingly understood with intense research in recent years. Several important intracellular signaling pathways such as the Ras/Raf/Mek/Erk pathway and PI3k/Akt/mTOR pathway have been recognized, and the role of several growth factors and angiogenic factors such as EGF and VEGF has been confirmed. Effective agents targeting these molecular abnormalities have been developed and widely tested in preclinical studies of HCC cell lines or xenograft models. Several agents have entered clinical trials in HCC patients, and recent data indicated that a multikinase inhibitor targeting Ras kinase and VEGFR-2, sorafenib, is effective in prolonging survival of patients with advanced HCC. The management of advanced HCC is entering the era of molecular targeting therapy, which is of particular significance for HCC in view of the lack of existing effective systemic therapy for this cancer.
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PMID:From molecular biology to targeted therapies for hepatocellular carcinoma: the future is now. 1808 80

Growth factors and their corresponding receptors are commonly overexpressed and/or dysregulated in many cancers including hepatocellular cancer (HCC). Clinical trials indicate that growth factor receptors and their related signalling pathways play important roles in HCC cancer etiology and progression, thus providing rational targets for innovative cancer therapies. A number of strategies including monoclonal antibodies, tyrosine kinase inhibitors ("small molecule inhibitors") and antisense oligonucleotides have already been evaluated for their potency to inhibit the activity and downstream signalling cascades of these receptors in HCC. First clinical trials have also shown that multi-kinase inhibition is an effective novel treatment strategy in HCC. In this respect sorafenib, an inhibitor of Raf-, VEGF- and PDGF-signalling, is the first multi-kinase inhibitor that has been approved by the FDA for the treatment of advanced HCC. Moreover, the serine-threonine kinase of mammalian target of rapamycin (mTOR) upon which the signalling of several growth factor receptors converge plays a central role in cancer cell proliferation. mTOR inhibition of HCC is currently also being studied in preclinical trials. As HCCs represent hypervascularized neoplasms, inhibition of tumour vessel formation via interfering with the VEGF/VEGFR system is another promising approach in HCC treatment. This review will summarize the current status of the various growth factor receptor-based treatment strategies and in view of the multitude of novel targeted approaches, the rationale for combination therapies for advanced HCC treatment will also be taken into account.
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PMID:Growth factor receptors and related signalling pathways as targets for novel treatment strategies of hepatocellular cancer. 1817 55

The present study was undertaken to characterize neuronal activity-dependent expression and release of vascular endothelial growth factor (VEGF) from rat hippocampal neurons and its contribution to neuronal functions. Increased levels of VEGF164 mRNA were evident both in cultured neurons and slices, but not astrocytes, following membrane depolarization with KCl. Activity-dependent expression of VEGF, as well as its release, was dependent on the activation of the N-methyl-d-aspartate receptors or L-type voltage-activated calcium channels. A brief (10 min) application of recombinant VEGF165 to neurons elicited a slow rise in cytosolic Ca2+ in a VEGFR2 dependent manner. The VEGF-induced Ca2+ responses required Ca2+ influx, phospholipase Cgamma and Ca2+ stores. An inhibitor of transient receptor potential canonical channels reduced the VEGF-induced Ca2+ responses by 50%, suggesting the involvement of transient receptor potential canonical channels in the VEGF-mediated responses. The same brief stimulus with VEGF led to long-term synaptic enhancement dependent on protein synthesis. VEGF had prominent effects on the activation calcium/calmodulin protein kinase II and cAMP responsive element binding protein as well as extracellular signal-regulated protein kinase and mammalian target of rapamycin-all in a VEGFR2 dependent manner. Our findings suggest that VEGF released from neuronal cells plays a local role in Ca2+ influx and synaptic transmission that may influence the generation of long-term changes in synaptic efficacy.
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PMID:Vascular endothelial growth factor (VEGF) signaling regulates hippocampal neurons by elevation of intracellular calcium and activation of calcium/calmodulin protein kinase II and mammalian target of rapamycin. 1822 55

Cytokine-based therapeutic approaches using interferon (IFN) and interleukin 2 (IL-2) were conventionally applied for the treatment of progressive RCC. Caused by the limited effectiveness of cytokine-based approaches in advanced renal cell carcinoma, new substances were needed. Among these, the "targeted therapies", particularly the group of the tyrosine kinase inhibitors, are of main interest. At present, multikinase inhibitors and antiangiogenic agents (VEGFR, PDGFR-beta, and mTOR) are used in first- and second-line therapies of metastatic RCC in various clinical studies. This review presents and discusses the effectiveness of the most frequently used substances in mono- or combination regimes based on current data of the ASCO 2007.
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PMID:Novel therapeutic options in metastatic renal cancer - review and post ASCO 2007 update. 1878 79

The proof of principle that a drug targeting mTOR can improve survival has been obtained recently from a large randomised trial using temsirolimus as a first-line therapy in patients with advanced poor prognostic renal cell carcinoma. Consistent data have recently shown the important role of the PI3K/AKT/mTOR signalling pathway in the regulation of crucial metabolic and mitotic functions of cancer cells and endothelial cells allowing a better understanding of the role of mTOR in controlling cancer cell proliferation and survival as well as tumour angiogenesis. As a result, rapamycin derivatives (rapalogues) that block mTOR/Raptor complex 1 were shown to exert direct antiproliferative effects against endometrial cancers, in which cancer cells frequently lose PTEN function as well as mantle cell lymphomas, in which cancer cell proliferation appears to be driven primarily by cyclin D1 overexpression. The overall antitumour effects of rapalogues in renal cell carcinoma appear to be more complex with tumour growth inhibition resulting from direct G1/S cell cycle blockage and/or apoptotic effects in carcinoma cells along with the inhibition of downstream signalling of the HIF1alpha-induced VEGF/VEGFR autocrine loop in endothelial cells shutting down the maintenance of tumour angiogenesis. Despite extensive cognitive researches, it is difficult to appraise which of those mechanisms is predominant in patients. This review focuses on mechanisms of action of rapalogues focusing on antitumour effects in patients with renal cell carcinoma.
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PMID:mTORC1 inhibitors: is temsirolimus in renal cancer telling us how they really work? 1879 63


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