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 development of immunosuppressive agents reflects the progress in understanding the cellular and molecular mechanisms which mediate allograft rejection. Six paradigms represent the evolution of immunosuppressive strategies for organ transplantation. The proliferation paradigm advances agents which interrupt lymphocyte cell division (azathioprine, cyclophosphamide, mycophenolic acid). The depletion paradigm conscripts drugs that bind to lymphocyte cell surface markers, thereby producing cell lysis and/or inactivation (polyclonal ATGAM and thymoglobulin, and monoclonal OKT3 antilymphocyte antibodies). The cytokine paradigm uses agents that interrupt lymphocyte maturational events; eg, synthesis (calcineurin inhibitors: cyclosporine/tacrolimus), binding to surface receptors (anti-CD25 mAbs), or signal transduction phases of cytokine stimulation (sirolimus). The introduction of calcineurin inhibitors markedly reduces the rate of acute rejection episodes and increases short-term graft survival rates; nephrotoxicity and chronic allograft attrition remain as unanswered challenges. The cyclosporine A (CsA) sparing property of sirolimus permits the use of lower exposure to calcineurin agents, allows for early withdrawal of steroid therapy, and may delay allograft senescence. Furthermore, the combination of SRL with anti-IL-2R mAbs proffers an induction approach which allows prolonged periods of holiday from calcineurin inhibitors. To address the tissue nonselectivity of the calcineurin and mTOR inhibitors, which presumably causes the drug toxicities, new agents are being developed to selectively inhibit the T cell target Janus Kinase 3. In the costimulation paradigm, the accessory signals generated by antigen-presenting cells are interrupted by distinct agents: the receptor conjugate CTLA4-immunoglobulin and anti-B7 or anti-CD40 ligand mAbs. Another set of drugs (selectin blocking agents, anti-ICAM-1 antisense deoxy oligonucleotides, and the lymphocyte homing inhibitor FTY720) seeks to modulate the ischemia-reperfusion injury, which exacerbates cytokine-mediated events in the donor and the subsequent procurement injury and may also accelerate the progression of transplant senescence. Finally, the transplantation tolerance paradigm is based on the development of strategies which distort alloimmune recognition by antigen reactive cells (MHC peptides or proteins), produce anergy (costimulation blockers), functional inactivation, or deletion of antigen-reactive cells (donor bone marrow infusions and gene therapy). Presently, the optimal immunosuppressive strategy uses combinations of agents that act in synergistic fashion to provide the potency, freedom from toxic reactions, convenience of administration, and cost appropriate for the individual patient.
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PMID:Immunosuppressive agents in organ transplantation: past, present, and future. 1074 55

In the past 10 to 15 years, the number of approved agents for treatment of colorectal cancer has expanded from only one (in 1995) to seven (as of 2006), with the most recent additions being the targeted agents cetuximab, bevacizumab, and panitumumab. While real progress has been made, these advances have translated into more modest improvements in patient outcomes than had been anticipated. Better understanding of the molecular underpinnings of colorectal cancer and of each patient's genetic makeup will likely improve the selection of treatment for each individual, leading to reduced toxicity and cost in patients spared therapy because they are unlikely to respond, and higher benefit in the subset of patients harboring the target of interest. KRAS mutational status was recently identified as an important marker for response to EGFR-directed therapies, and other pathways being explored include the immune system (anti-cytotoxic T lymphocyte antigen 4 [anti-CTLA4] monoclonal antibodies), insulin-like growth factor 1 receptor (IGF1R) (IGF1R monoclonal antibodies), the mammalian target of rapamycin (mTOR) (mTOR kinase inhibitors), and others. Results of trials evaluating agents targeting these pathways are awaited. New paradigms and treatments are needed to advance the landscape for patients with advanced and metastatic colorectal cancer.
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PMID:Colorectal Cancer Treatment: What's Next? (or: Is There Life After EGFR and VEGF?). 1934 43

In this study, we demonstrate that the E3 ubiquitin ligase gene related to anergy in lymphocytes (GRAIL) is expressed in quiescent naive mouse and human CD4 T cells and has a functional role in inhibiting naive T cell proliferation. Following TCR engagement, CD28 costimulation results in the expression of IL-2 whose signaling through its receptor activates the Akt-mammalian target of rapamycin (mTOR) pathway. Activation of mTOR allows selective mRNA translation, including the epistatic regulator of GRAIL, Otubain-1 (Otub1), whose expression results in the degradation of GRAIL and allows T cell proliferation. The activation of mTOR appears to be the critical component of IL-2R signaling regulating GRAIL expression. CTLA4-Ig treatment blocks CD28 costimulation and resultant IL-2 expression, whereas rapamycin and anti-IL-2 treatment block mTOR activation downstream of IL-2R signaling. Thus, all three of these biotherapeutics inhibit mTOR-dependent translation of mRNA transcripts, resulting in blockade of Otub1 expression, maintenance of GRAIL, and inhibition of CD4 T cell proliferation. These observations provide a mechanistic pathway sequentially linking CD28 costimulation, IL-2R signaling, and mTOR activation as important requirements for naive CD4 T cell proliferation through the regulation of Otub1 and GRAIL expression. Our findings also extend the role of GRAIL beyond anergy induction and maintenance, suggesting that endogenous GRAIL regulates general cell cycle and proliferation of primary naive CD4 T cells.
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PMID:Naive CD4 t cell proliferation is controlled by mammalian target of rapamycin regulation of GRAIL expression. 1941 43

Over 65,000 Americans are diagnosed with kidney cancer each year and nearly 13,000 die of this disease. Kidney cancer is not a single disease, it is made up of a number of different types of cancer, each with a different histology, a different clinical course, responding differently to therapy and caused by a different gene. Study of the 13 genes that are known to cause kidney cancer has led to the understanding that kidney cancer is a metabolic disease. Recent discoveries of chromatin remodeling/histone modifying genes, such as PBRM1 and SETD2, have opened up new areas of intense interest in the study of the fundamental genetic basis of kidney cancer. New approaches to immunotherapy with agents such as the CTLA4 inhibitor, ipilumumab, have opened up promising new directions for clinical trials. A number of new agents targeting of VEGF receptor signaling and the mTOR pathways as well as novel approaches targeting HIF2 will hopefully provide the foundation for the development of effective forms of therapy for this disease.
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PMID:Kidney cancer. 2321 74

ILT3(high)ILT4(high) dendritic cells (DCs) may cause anergy in CD4(+)CD45RO(+)CD25(+) T cells transforming them into regulatory T cells (Tregs). Here, we tested whether chronic exposure to rapamycin may modulate this immunoregulatory pathway in renal transplant recipients. Forty renal transplant patients with biopsy-proven chronic allograft nephropathy and receiving calcineurin inhibitors were randomly assigned to either calcineurin inhibitor dose reduction or withdrawal with rapamycin introduction. At conversion and 2 years thereafter, we measured the rapamycin effects on circulating DCs (BDCA1/BDCA2 and ILT3/ILT4 expression), CD4(+)/CD25(high)/Foxp3(+) Tregs, CD8(+)/CD28(-) T cells, and the Th1/Th2 balance in graft biopsies. In rapamycin-treated patients, peripheral BDCA2(+) cells were significantly increased along with ILT3/ILT4(+) DCs. The number of circulating CD4(+)/CD25(high)/Foxp3(+)/CTLA4(+) Tregs, CD8(+)CD28(-) T cells, and HLA-G serum levels were higher in the rapamycin-treated group. The number of ILT3/ILT4(+)BDCA2(+) DC was directly and significantly correlated with circulating Tregs and CD8(+)CD28(-) T cells. ILT3/ILT4 expression was increased in kidney biopsies at the end of the study period along with a significant bias toward a Th2 response within the graft only in the rapamycin-treated patients. Thus, rapamycin induces the upregulation of ILT3 and ILT4 on the DC surface, and this effect is associated with an increase in the number of Tregs and expansion of the CD8(+)CD28(-) T cell population. This suggests that mTOR inhibition may promote a novel immunoregulatory pathway.
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PMID:Rapamycin induces ILT3(high)ILT4(high) dendritic cells promoting a new immunoregulatory pathway. 2468 22

Targeted therapies have developed rapidly over the last few years in the field of oncology thanks to a better understanding of carcinogenesis. They target pathways involved in signal transduction (EGFR, HER2, HER3, HER4, FLT3, RAS, RAF, MEK, KIT, RET, mTOR, SRC, EPH, SCF), tumor angiogenesis (VEGFR, TIE2), and tumor microenvironment (PDGFR, FGFR). They rarely cause the systemic adverse reactions generally associated with chemotherapy, but frequently cause disabling and specific skin toxicity. The impact on patient quality of life can be important both in terms of symptoms caused and of potentially aesthetic consequences. Inappropriate management can increase the risk of dose reduction or discontinuation of the cancer treatment. In this review, we will discuss skin toxicity associated with the main drug classes-EGFR, BRAF, MEK, mTOR, c-KIT, CTLA4, and SMO inhibitors, and anti-angiogenic agents. Targeted therapy-induced skin toxicities will be detailed in terms of symptoms, frequency, evolution, complications, and topical and oral treatments in order to improve their diagnosis and management.
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PMID:Dermatological toxicity associated with targeted therapies in cancer: optimal management. 2511 53

Treatment of muscle invasive urothelial bladder carcinoma (BCa) remains a major challenge. Comprehensive genomic profiling of tumors and identification of driver mutations may reveal new therapeutic targets. This manuscript discusses relevant molecular drivers of the malignant phenotype and agents with therapeutic potential in BCa. Small molecule pan-FGFR inhibitors have shown encouraging efficacy and safety results especially among patients with activating FGFR mutations or translocations. mTOR inhibitors for patients with TSC1 mutations and concomitant targeting of PI3K and MEK represent strategies to block PI3K/AKT/mTOR pathway. Encouraging preclinical results with ado-trastuzumab emtansine (T-DM1) exemplifies a new potential treatment for HER2-positive BCa along with innovative bispecific antibodies. Inhibitors of cell cycle regulators (aurora kinase, polo-like kinase 1, and cyclin-dependent kinase 4) are being investigated in combination with chemotherapy. Early results of clinical studies with anti-CTLA4 and anti-PDL1 are propelling immune modulating drugs to the forefront of emerging treatments for BCa. Collectively, these novel therapeutic targets and treatment strategies hold promise to improve the outcome of patients afflicted with this malignancy.
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PMID:Emerging therapeutic targets in bladder cancer. 2549 41

Latent viral infections are a major concern among immunosuppressed transplant patients. During clinical trials with belatacept, a CTLA4-Ig fusion protein, patients showed an increased risk of Epstein-Barr virus-associated posttransplant lymphoproliferative disorder, thought to be due to a deficient primary CD8(+) T cell response to the virus. Using a murine model of latent viral infection, we observed that rapamycin treatment alone led to a significant increase in virus-specific CD8(+) T cells, as well as increased functionality of these cells, including the ability to make multiple cytokines, while CTLA4-Ig treatment alone significantly dampened the response and inhibited the generation of polyfunctional antigen-specific CD8(+) T cells. However, the addition of rapamycin to the CTLA4-Ig regimen was able to quantitatively and qualitatively restore the antigen-specific CD8(+) T cell response to the virus. This improvement was physiologically relevant, in that CTLA4-Ig treated animals exhibited a greater viral burden following infection that was reduced to levels observed in untreated immunocompetent animals by the addition of rapamycin. These results reveal that modulation of T cell differentiation though inhibition of mTOR signaling can restore virus-specific immune competence even in the absence of CD28 costimulation, and have implications for improving protective immunity in transplant recipients.
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PMID:Rapamycin ameliorates the CTLA4-Ig-mediated defect in CD8(+) T cell immunity during gammaherpesvirus infection. 2598

Invasive bladder cancer, for which there have been few therapeutic advances in the past 20 years, is a significant medical problem associated with metastatic disease and frequent mortality. Although previous studies had identified many genetic alterations in invasive bladder cancer, recent genome-wide studies have provided a more comprehensive view. Here, we review those recent findings and suggest therapeutic strategies. Bladder cancer has a high mutation rate, exceeded only by lung cancer and melanoma. About 65% of all mutations are due to APOBEC-mediated mutagenesis. There is a high frequency of mutations and/or genomic amplification or deletion events that affect many of the canonical signaling pathways involved in cancer development: cell cycle, receptor tyrosine kinase, RAS, and PI-3-kinase/mTOR. In addition, mutations in chromatin-modifying genes are unusually frequent in comparison with other cancers, and mutation or amplification of transcription factors is also common. Expression clustering analyses organize bladder cancers into four principal groups, which can be characterized as luminal, immune undifferentiated, luminal immune, and basal. The four groups show markedly different expression patterns for urothelial differentiation (keratins and uroplakins) and immunity genes (CD274 and CTLA4), among others. These observations suggest numerous therapeutic opportunities, including kinase inhibitors and antibody therapies for genes in the canonical signaling pathways, histone deacetylase inhibitors and novel molecules for chromatin gene mutations, and immune therapies, which should be targeted to specific patients based on genomic profiling of their cancers.
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PMID:Invasive Bladder Cancer: Genomic Insights and Therapeutic Promise. 2647 86

American Neurological Association Annual Meeting, Chicago, IL, USA, 27-29 September 2015 The American Neurological Association (ANA) held its annual meeting in Chicago, IL, USA on 27-29 September 2015. The Scientific Programming Advisory Committee was chaired by Dr. S Pleasure from the University of California-San Francisco (CA, USA). The Neuro-Oncology session, chaired by Dr. A Pruitt from the University of Pennsylvania (PA, USA) and cochaired by Dr. J Laterra from Johns Hopkins University (MD, USA), was held on 27 September 2015. Speakers included Dr. D Wainwright (Northwestern University, IL, USA), Dr. N Kolb (University of Utah, UT, USA), Dr. A Nath (NINDS/NIH, MD, USA), Dr. D Franz (Cincinnati Children's Hospital, OH, USA) and Dr. R Lukas (University of Chicago, IL, USA). A summary of key presentations from the Neuro-Oncology section of the 2015 American Neurological Association annual meeting is reported. Preclinical and clinical advances in the use of immunotherapies for the treatment of primary and metastatic CNS tumors are covered. Particular attention is paid to the enzyme indoleamine dioxygenase and the immune checkpoints CTLA4 and PD1 and their ligands. Specific nervous system toxicities associated with novel immunotherapies are also discussed. The recent success of targeting the mTOR pathway in the neurocutaneous syndrome tuberous sclerosis is detailed. Finally, important early steps in our understanding of the common toxicity of chemotherapy induced neuropathy are reviewed.
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PMID:Updates from the Neuro-Oncology Section of the 2015 American Neurological Association Annual Meeting. 2661 37


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