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

The targeted therapies sunitinib, sorafenib, temsirolimus, and bevacizumab (when used in combination with interferon-alpha2a) have dramatically improved outcomes for patients with advanced renal cell carcinoma (RCC). Clinical application of these novel agents outside the trial setting, however, may present some challenges for treating individual patients with unique needs. In some patients, dose modifications may be considered for potential drug interactions and for management of severe cases of hematologic or nonhematologic toxicities. The more common grade 3 or 4 side effects with sunitinib and sorafenib include hypertension, fatigue, hand-foot syndrome, elevated lipase, lymphopenia, and neutropenia. Congestive heart failure is a less common but serious side effect that warrants treatment discontinuation. Temsirolimus exhibits a different side-effect profile, with the more common grade 3 or 4 side effects being metabolic in nature (i.e., elevated triglycerides, elevated glucose, hypophosphatemia) as a result of its inhibitory effects on the mammalian target of rapamycin-regulated lipid and glucose pathways. Asthenia, rash, and dyspnea also occur in patients receiving temsirolimus. Virtually all of the side effects associated with these agents can be managed effectively in the majority of patients with medical treatment or supportive interventions. Recognition and prompt management of side effects are important to avoid unnecessary dose reductions that may result in suboptimal efficacy.
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PMID:Targeted therapies for metastatic renal cell carcinoma: an overview of toxicity and dosing strategies. 1883 39

The mammalian target of rapamycin (mTOR) protein complex functions as an integration center for various intracellular signaling pathways involving cell cycle progression, proliferation, and angiogenesis. These pathways are frequently dysregulated in cancer, and therefore mTOR inhibition is a potentially important antitumor target. Commercially available mTOR inhibitors include rapamycin (i.e., sirolimus) and temsirolimus. Other agents under investigation include everolimus and deforolimus. mTOR inhibition has been studied in various solid tumors, including breast, gynecologic, gastrointestinal, prostate, lung, and head and neck cancers. Studies have focused on mTOR inhibition as a monotherapy or in combination with other drugs based on the principle that inhibiting as many targets as possible reduces the emergence of drug resistance. Temsirolimus is currently the only mTOR inhibitor that is specifically labeled for treatment of solid tumors. However, preclinical studies and early-phase trials are rapidly evolving. Additionally, research is further defining the complicated mTOR pathways and how they may be disordered in specific malignancies. To address these issues, NCCN convened a task force to review the underlying physiology of mTOR and related cellular pathways, and to review the current status of research of mTOR inhibition in solid tumors.
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PMID:NCCN Task Force Report: mTOR inhibition in solid tumors. 1892 92

Research into mTOR, mammalian Target Of Rapamycin as an important drug target continues to be extremely interesting, both in terms of the increased molecular knowledge being acquired at the basis of various human diseases, and also for possible applications in drug cancer therapy. The mTOR signaling system plays a key role in several transduction pathways that are necessary for cell cycle progression and cellular proliferation. Drugs known as mTOR inhibitors have been included in ongoing and in recently completed cancer trials. New insights into the mTOR signaling system are helping to clarify the functionality of key mTOR components, and especially their possible role in apoptosis, angiogenesis and tumor progression. Three other molecules, already approved for therapeutic use and being commercialized (Everolimius, Temsirolimus and Zotarolimus) are added to Rapamycin (also known as Sirolimus), the parent drug of the mTOR inhibitors. Of these, only Temsirolimus is currently approved in the treatment of renal cell carcinoma, while the others are approved for organ transplant rejection and coronary artery restenosis. There are at least 10 other molecules currently under development for clinical and preclinical studies. This review offers an updated synopsis of the mTOR signaling system, in particular as regards relevant aspects of cancer research, looks at the known mTOR inhibitors and gives a systematic vision of current trials for each individual molecule subject to clinical investigation.
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PMID:mTOR pathway and mTOR inhibitors as agents for cancer therapy. 1907 88

Patients with metastatic renal cell carcinoma (RCC) generally show a poor prognosis; treatment approaches have not significantly improved patient survival. Temsirolimus inhibits the mammalian target of rapamycin kinase. Clinical studies have shown positive results when the drug is administered to patients with this disease. The clinical benefit of temsirolimus for poor-risk, advanced RCC patients was demonstrated in a Phase III study comparing temsirolimus with interferon alpha (IFN-alpha) or combined temsirolimus plus IFN-alpha as first-line treatment of advanced RCC, showed that treatment with temsirolimus alone significantly increased median overall survival in poor-risk, advanced RCC patients (10.9 vs 7.3 vs 8.4 months). This was the first Phase III trial to demonstrate an overall improvement in survival using an agent as "targeted therapy" for patients with advanced RCC. By November 2007, 200 patients with advanced RCC had been treated with temsirolimus before its approval by the European Medicines Agency (EMEA) within a compassionate use program. The single-center treatment experiences using temsirolimus in patients for compassionate use are described herein. The treatment was generally well tolerated; side effects (mucositis, diabetes, and peripheral edema) were within the range expected from the pivotal trials and manageable with supportive care. Further development strategies for temsirolimus in patients with RCC include its evaluation with bevacizumab and also as second-line therapy in patients who have failed first-line therapy with sunitinib.
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PMID:Temsirolimus in renal cell carcinoma. 1910 Sep 5

Treatment of patients with advanced renal cell carcinoma (RCC) has changed dramatically with the advent of targeted therapeutics. Temsirolimus, an inhibitor of mammalian target of rapamycin (mTOR), has proven beneficial in the treatment of advanced RCC with poor prognosis. The rationale for mTOR inhibitors in treatment of RCC, the pharmacokinetics and toxicities of temsirolimus, landmark clinical trials of temsirolimus in advanced RCC, and the indications for its use in the treatment of RCC are reviewed here. The status of temsirolimus in the rapidly evolving therapeutic landscape of advanced RCC is also discussed.
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PMID:Temsirolimus in patients with advanced renal cell carcinoma: an overview. 1917 39

Protein kinases catalyse key phosphorylation reactions in signalling cascades that affect every aspect of cell growth, differentiation and metabolism. The kinases have become prime targets for drug intervention in the diseased state, especially in cancer. There are currently 10 drugs that have been approved for clinical use and many more in clinical trials. This review summarises the structural basis for protein kinase inhibition and discusses the mode of action for each of the approved drugs in the light of structural results. All but one of the approved compounds target the ATP binding site on the kinase. Both the active and inactive conformations of protein kinases have been used in strategies to produce potent and selective compounds. Targeting the inactive conformation can give high specificity. Targeting the active conformation is favourable where the diseased state has arisen from activating mutations, but such inhibitors generally target several protein kinases. Drug resistance mutations are a potential risk for both conformational states, where drug-binding regions are not directly involved in catalysis. Imatinib (Glivec), the most successful of protein kinase inhibitors, targets the inactive conformation of ABL tyrosine kinase. Newer compounds, such as dasatinib, which targets the ABL active state, have been developed to increase potency and have proved effective for some, but not all, drug-resistant mutations. The first epidermal growth factor receptor (EGFR) inhibitors in clinical use [gefitinib (Iressa) and erlotinib (Tarceva)] targeted the active form of the kinase, and this proved advantageous for patients whose cancer was caused by mutations that resulted in a constitutively active EGFR kinase domain. Newer approved compounds, such as lapatinib (Tykerb), target the inactive conformation with high potency. A further compound that forms a covalent attachment to the kinase has been found to overcome one of the major drug resistance mutations, where the effectiveness of the drug in vivo is dependent on its ability to compete successfully in the presence of cellular concentrations of ATP. Inhibitors of vascular endothelial growth factor receptor (VEGFR) kinase against cancer angiogenesis show the advantage of some relaxation in specificity. Sorafenib, originally developed as RAF inhibitor, is now in clinical use as a VEGFR inhibitor. Temsirolimus (a derivative of rapamycin) is the only example of a drug in clinical use that does not target the kinase ATP site. Instead rapamycin, when in complex with the protein FKBP12, effectively targets mTOR kinase at a site located on a domain, the FRB domain, that appears to be involved in localisation or substrate docking.
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PMID:Protein kinase inhibitors: contributions from structure to clinical compounds. 1929 66

Clinical trials have validated the importance of mammalian target of rapamycin (mTOR) as a targeted mechanism in the treatment of renal cell carcinoma (RCC). Temsirolimus, an mTOR inhibitor that is approved for treatment of advanced RCC, has demonstrated both overall survival benefits and progression-free survival benefits versus interferon-alpha as first-line treatment for patients with poor prognostic features. Exploratory subset analyses indicated that temsirolimus benefits patients with RCC regardless of tumor histology or nephrectomy status. Everolimus, the second mTOR inhibitor to demonstrate activity in RCC, improved progression-free survival versus placebo in patients whose disease progressed after treatment with vascular endothelial growth factor receptor tyrosine kinase inhibitors (sunitinib, sorafenib, or both); benefit was observed for all risk groups. Deforolimus also exhibited antitumor activity against RCC in early clinical studies. There is now compelling clinical evidence for the effectiveness of targeting mTOR in the treatment of RCC.
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PMID:Targeted inhibition of mammalian target of rapamycin for the treatment of advanced renal cell carcinoma. 1947 76

The mammalian target of rapamycin(mTOR)and its molecular pathways are supposed to be activated frequently in human renal cell carcinoma as well as other cancers. It has a kinase activity for 40S ribosomal protein kinase and eukaryotic translation initiation factor 4E-binding protein 1. These proteins, when phosphorylated, promote protein translation and RNA transcription in the nutrient-rich condition. mTOR inhibitors such as Temsirolimus (CCI779) and Everolimus (RAD001) are effective for suppressing cell growth with inhibiting mTOR kinase activity. Rapamycin and its related analogs such as Temsirolimus and Everolimus are less toxic for humans compared with other anti-VEGFR inhibitors and has been used as an immunosuppressive agent. These agents have an inhibitory activity against the mTORC1 complex. Since they do not have inhibitory activity against mTORC2 complex, the ability of mTOR inhibition by Temsirolimus is supposed to be 40 to 50% of full inhibition in mTOR kinase. Temsirolimus has modest anticancer activity against advanced clinical RCC patients with poor risk. The objective response rate was only 7%, 26% of patients experienced minor responses and another 17% of patients had stable disease that lasted 6 months. The median time to tumor progression and median survival for the study patients were 5.8 and 15.0 months, respectively. The overall survival of patients treated with Temsirolimus alone was statistically longer than in those treated with IFN alone in the 626 cases in phase II study. Combinations of mTOR with other anti- VEGFR agents were not effective. Vertical therapies of mTOR inhibitor in combination with AKT inhibitors, or newly development of stronger mTOR kinase which can suppress both mTORC1 and mTORC2 are planned at present.
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PMID:[Mammalian target of rapamycin, its mode of action and clinical response in metastatic clear cell carcinoma]. 1962 Jul 95

We present a case of a 73-year-old female with metastatic renal cell carcinoma, clear cell histologic subtype, who developed pruritic rash after 2 weeks of 25 mg weekly infusions of temsirolimus. Rash was located on bilateral antecubital areas and posterior knees. Skin biopsy showed spongiotic dermatitis with eosinophils. Based on history and clinical examination, a diagnosis of drug rash secondary to temsirolimus was made. Temsirolimus is a small-molecule inhibitor of the mammalian target of rapamycin (mTOR). Inhibition of mTOR kinase results in cell cycle arrest, antiangiogenesis, and apoptosis. The mechanism of skin toxicity is unknown; however, it can be hypothesized that there is a direct inhibitory effect on signaling pathways that regulate cell growth and tissue repair. The mTOR kinase inhibitor temsirolimus has shown great promise in increasing overall survival in patients with metastatic renal cell carcinoma. Dermatologic toxicities are among the most prevalent and necessitate early recognition and management, in order to maintain quality of life and consistent therapy. The patient presented was initiated on topical clobetasol resulting in rash resolution at a 2-week follow-up visit.
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PMID:Eosinophilic rash secondary to temsirolimus. 1969 20

We investigated the genotype-dependent therapeutic potential of targeting the phosphoinositide 3-kinase (PI3K)/Akt pathway for thyroid cancer. Proliferation of TPC1, Hth7, FTC133, OCUT1, K1, and BCPAP cells that harbored PI3K/Akt-activating genetic alterations was potently inhibited by the Akt inhibitor perifosine, whereas SW1736, Hth74, WRO, KAT18, and TAD2 cells that harbored no genetic alterations had no or only modest responses. Inhibition of Akt phosphorylation by perifosine was seen in these cells. Genetic-dependent apoptosis was induced by perifosine in cells selectively tested. Similarly, potent inhibition of cell proliferation by the mammalian target of rapamycin (mTOR) inhibitor temsirolimus occurred in virtually all the cells harboring genetic alterations, whereas modest inhibition was seen in some of the cells not harboring genetic alterations. Temsirolimus inhibited the phosphorylation of p70S6K, a substrate of mTOR. Knockdown of Akt1/2 or mTOR by shRNA approach inhibited the proliferation and colony formation of FTC133 and OCUT1 cells that harbored genetic alterations in the PI3K/Akt pathway but had no effect on SW1736 and KAT18 cells that did not. Transfection with PIK3CA mutants greatly sensitized SW1736 cells to perifosine and temsirolimus. Growth of xenograft tumors derived from FTC133 cells but not SW1736 cells in nude mice was dramatically inhibited by perifosine. Thus, this work for the first time shows that genetic alterations in the PI3K/Akt pathway confer thyroid cancer cells addiction to this pathway and their sensitivity to inhibition by targeting Akt and mTOR. This genotype-based targeting of the PI3K/Akt pathway using Akt and mTOR inhibitors may offer an effective therapeutic strategy for thyroid cancer and warrants further studies.
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PMID:Genetic alterations in the phosphoinositide 3-kinase/Akt signaling pathway confer sensitivity of thyroid cancer cells to therapeutic targeting of Akt and mammalian target of rapamycin. 1970 58


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