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  1. Delayed mTOR Inhibition with Low Dose of Everolimus Reduces TGFβ Expression, Attenuates Proteinuria and Renal Damage in the Renal Mass Reduction Model

    PubMed Central

    Kurdián, Melania; Herrero-Fresneda, Inmaculada; Lloberas, Nuria; Gimenez-Bonafe, Pepita; Coria, Virginia; Grande, María T.; Boggia, José; Malacrida, Leonel; Torras, Joan; Arévalo, Miguel A.; González-Martínez, Francisco; López-Novoa, José M.; Grinyó, Josep; Noboa, Oscar

    2012-01-01

    Background The immunosuppressive mammalian target of rapamycin (mTOR) inhibitors are widely used in solid organ transplantation, but their effect on kidney disease progression is controversial. mTOR has emerged as one of the main pathways regulating cell growth, proliferation, differentiation, migration, and survival. The aim of this study was to analyze the effects of delayed inhibition of mTOR pathway with low dose of everolimus on progression of renal disease and TGFβ expression in the 5/6 nephrectomy model in Wistar rats. Methods This study evaluated the effects of everolimus (0.3 mg/k/day) introduced 15 days after surgical procedure on renal function, proteinuria, renal histology and mechanisms of fibrosis and proliferation. Results Everolimus treated group (EveG) showed significantly less proteinuria and albuminuria, less glomerular and tubulointerstitial damage and fibrosis, fibroblast activation cell proliferation, when compared with control group (CG), even though the EveG remained with high blood pressure. Treatment with everolimus also diminished glomerular hypertrophy. Everolimus effectively inhibited the increase of mTOR developed in 5/6 nephrectomy animals, without changes in AKT mRNA or protein abundance, but with an increase in the pAKT/AKT ratio. Associated with this inhibition, everolimus blunted the increased expression of TGFβ observed in the remnant kidney model. Conclusion Delayed mTOR inhibition with low dose of everolimus significantly prevented progressive renal damage and protected the remnant kidney. mTOR and TGFβ mRNA reduction can partially explain this anti fibrotic effect. mTOR can be a new target to attenuate the progression of chronic kidney disease even in those nephropathies of non-immunologic origin. PMID:22427849

  2. Cellular and molecular effects of the mTOR inhibitor everolimus.

    PubMed

    Saran, Uttara; Foti, Michelangelo; Dufour, Jean-François

    2015-11-01

    mTOR (mechanistic target of rapamycin) functions as the central regulator for cell proliferation, growth and survival. Up-regulation of proteins regulating mTOR, as well as its downstream targets, has been reported in various cancers. This has promoted the development of anti-cancer therapies targeting mTOR, namely fungal macrolide rapamycin, a naturally occurring mTOR inhibitor, and its analogues (rapalogues). One such rapalogue, everolimus, has been approved in the clinical treatment of renal and breast cancers. Although results have demonstrated that these mTOR inhibitors are effective in attenuating cell growth of cancer cells under in vitro and in vivo conditions, subsequent sporadic response to rapalogues therapy in clinical trials has promoted researchers to look further into the complex understanding of the dynamics of mTOR regulation in the tumour environment. Limitations of these rapalogues include the sensitivity of tumour subsets to mTOR inhibition. Additionally, it is well known that rapamycin and its rapalogues mediate their effects by inhibiting mTORC (mTOR complex) 1, with limited or no effect on mTORC2 activity. The present review summarizes the pre-clinical, clinical and recent discoveries, with emphasis on the cellular and molecular effects of everolimus in cancer therapy. PMID:26330617

  3. Differentiating the mTOR inhibitors everolimus and sirolimus in the treatment of tuberous sclerosis complex.

    PubMed

    MacKeigan, Jeffrey P; Krueger, Darcy A

    2015-12-01

    Tuberous sclerosis complex (TSC) is a genetic autosomal dominant disorder characterized by benign tumor-like lesions, called hamartomas, in multiple organ systems, including the brain, skin, heart, kidneys, and lung. These hamartomas cause a diverse set of clinical problems based on their location and often result in epilepsy, learning difficulties, and behavioral problems. TSC is caused by mutations within the TSC1 or TSC2 genes that inactivate the genes' tumor-suppressive function and drive hamartomatous cell growth. In normal cells, TSC1 and TSC2 integrate growth signals and nutrient inputs to downregulate signaling to mammalian target of rapamycin (mTOR), an evolutionarily conserved serine-threonine kinase that controls cell growth and cell survival. The molecular connection between TSC and mTOR led to the clinical use of allosteric mTOR inhibitors (sirolimus and everolimus) for the treatment of TSC. Everolimus is approved for subependymal giant cell astrocytomas and renal angiomyolipomas in patients with TSC. Sirolimus, though not approved for TSC, has undergone considerable investigation to treat various aspects of the disease. Everolimus and sirolimus selectively inhibit mTOR signaling with similar molecular mechanisms, but with distinct clinical profiles. This review differentiates mTOR inhibitors in TSC while describing the molecular mechanisms, pathogenic mutations, and clinical trial outcomes for managing TSC. PMID:26289591

  4. Targeting the mTOR Complex by Everolimus in NRAS Mutant Neuroblastoma

    PubMed Central

    Kiessling, Michael K.; Curioni-Fontecedro, Alessandra; Samaras, Panagiotis; Lang, Silvia; Scharl, Michael; Aguzzi, Adriano; Oldrige, Derek A.; Maris, John M.; Rogler, Gerhard

    2016-01-01

    High-risk neuroblastoma remains lethal in about 50% of patients despite multimodal treatment. Recent attempts to identify molecular targets for specific therapies have shown that Neuroblastoma RAS (NRAS) is significantly mutated in a small number of patients. However, few inhibitors for the potential treatment for NRAS mutant neuroblastoma have been investigated so far. In this in-vitro study, we show that MEK inhibitors AZD6244, MEK162 and PD0325901 block cell growth in NRAS mutant neuroblastoma cell lines but not in NRAS wild-type cell lines. Several studies show that mutant NRAS leads to PI3K pathway activation and combined inhibitors of PI3K/mTOR effectively block cell growth. However, we observed the combination of MEK inhibitors with PI3K or AKT inhibitors did not show synergestic effects on cell growth. Thus, we tested single mTOR inhibitors Everolimus and AZD8055. Interestingly, Everolimus and AZD8055 alone were sufficient to block cell growth in NRAS mutant cell lines but not in wild-type cell lines. We found that Everolimus alone induced apoptosis in NRAS mutant neuroblastoma. Furthermore, the combination of mTOR and MEK inhibitors resulted in synergistic growth inhibition. Taken together, our results show that NRAS mutant neuroblastoma can be targeted by clinically available Everolimus alone or in combination with MEK inhibitors which could impact future clinical studies. PMID:26821351

  5. Antiinflammatory Activity of a Novel Folic Acid Targeted Conjugate of the mTOR Inhibitor Everolimus.

    PubMed

    Lu, Yingjuan; Parker, Nikki; Kleindl, Paul J; Cross, Vicky A; Wollak, Kristin; Westrick, Elaine; Stinnette, Torian W; Gehrke, Mark A; Wang, Kevin; Santhapuram, Hari Krishna R; You, Fei; Hahn, Spencer J; Vaughn, Jeremy F; Klein, Patrick J; Vlahov, Iontcho R; Low, Philip S; Leamon, Christopher P

    2015-01-01

    Folate receptor (FR)-β has been identified as a promising target for antimacrophage and antiinflammatory therapies. In the present study, we investigated EC0565, a folic acid-derivative of everolimus, as a FR-specific inhibitor of the mammalian target of rapamycin (mTOR). Because of its amphiphilic nature, EC0565 was first evaluated for water solubility, critical micelle formation, stability in culture and FR-binding specificity. Using FR-expressing macrophages, the effect of EC0565 on mTOR signaling and cellular proliferation was studied. The pharmacokinetics, metabolism and bioavailability of EC0565 were studied in normal rats. The in vivo activity of EC0565 was assessed in rats with adjuvant arthritis, a "macrophage-rich" model with close resemblance to rheumatoid arthritis. EC0565 forms micellar aggregates in physiological buffers and demonstrates good water solubility as well as strong multivalent FR-binding capacity. EC0565 inhibited mTOR signaling in rat macrophages at nanomolar concentrations and induced G0/G1 cell cycle arrest in serum-starved RAW264.7 cells. Subcutaneously administered EC0565 in rats displayed good bioavailability and a relatively long half-life (~12 h). When given at 250 nmol/kg, EC0565 selectively inhibited proliferating cell nuclear antigen expression in thioglycollate-stimulated rat peritoneal cells. With limited dosing regimens, the antiarthritic activity of EC0565 was found superior to that of etanercept, everolimus and a nontargeted everolimus analog. The in vivo activity of EC0565 was also comparable to that of a folate-targeted aminopterin. Folate-targeted mTOR inhibition may be an effective way of suppressing activated macrophages in sites of inflammation, especially in nutrient-deprived conditions, such as in the arthritic joints. Further investigation and improvement upon the physical and biochemical properties of EC0565 are warranted. PMID:26181632

  6. Everolimus

    MedlinePlus

    Everolimus comes as a tablet to take by mouth and as a tablet to suspend in water and take by mouth. When everolimus is taken ... more often than prescribed by your doctor.Everolimus tablets come in individual blister packs that can be ...

  7. Involvement of autophagy in the pharmacological effects of the mTOR inhibitor everolimus in acute kidney injury.

    PubMed

    Nakagawa, Shunsaku; Nishihara, Kumiko; Inui, Ken-ichi; Masuda, Satohiro

    2012-12-01

    Inhibitors of mammalian target of rapamycin (mTOR) have immunosuppressive and anti-cancer effects, but their effects on the progression of kidney disease are not fully understood. Using cells from normal kidney epithelial cell lines, we found that the antiproliferative effects of mTOR inhibitor everolimus accompanied the accumulation of a marker for cellular autophagic activity, the phosphatidylethanolamine-conjugated form of microtubule-associated protein 1 light chain 3 (LC3-II) in cells. We also showed that the primary autophagy factor UNC-51-like kinase 1 was involved in the antiproliferative effects of everolimus. Levels of LC3-II decreased in the kidneys of rats treated with ischemia-reperfusion or cisplatin; however, renal LC3-II levels increased after administration of everolimus to rats subjected to ischemia-reperfusion or cisplatin treatment. Simultaneously, increased signals for kidney injury molecule-1 and single-stranded DNA and decreased signals for Ki-67 in the proximal tubules were observed after treatment with everolimus, indicating that everolimus diminished renal function after acute tubular injury. We also found leakage of LC3 protein into rat urine after treatment with everolimus, and urinary LC3 protein was successfully measured between 0.1 and 500ng/mL by using an enzyme-linked immunosorbent assay. Urinary LC3 levels were increased after administration of everolimus to rats subjected to ischemia-reperfusion or cisplatin treatment, suggesting that renal LC3-II and urinary LC3 protein are new biomarkers for autophagy in acute kidney injury. Taken together, our results demonstrated that the induction of autophagy by everolimus aggravates tubular dysfunction during recovery from kidney injury. PMID:23022334

  8. Everolimus

    MedlinePlus

    ... you are taking everolimus.do not have any vaccinations without talking to your doctor. During your treatment ... been vaccinated.talk to your child's doctor about vaccinations that your child may need to receive before ...

  9. mTOR inhibition by everolimus in childhood acute lymphoblastic leukemia induces caspase-independent cell death.

    PubMed

    Baraz, Rana; Cisterne, Adam; Saunders, Philip O; Hewson, John; Thien, Marilyn; Weiss, Jocelyn; Basnett, Jordan; Bradstock, Kenneth F; Bendall, Linda J

    2014-01-01

    Increasingly, anti-cancer medications are being reported to induce cell death mechanisms other than apoptosis. Activating alternate death mechanisms introduces the potential to kill cells that have defects in their apoptotic machinery, as is commonly observed in cancer cells, including in hematological malignancies. We, and others, have previously reported that the mTOR inhibitor everolimus has pre-clinical efficacy and induces caspase-independent cell death in acute lymphoblastic leukemia cells. Furthermore, everolimus is currently in clinical trial for acute lymphoblastic leukemia. Here we characterize the death mechanism activated by everolimus in acute lymphoblastic leukemia cells. We find that cell death is caspase-independent and lacks the morphology associated with apoptosis. Although mitochondrial depolarization is an early event, permeabilization of the outer mitochondrial membrane only occurs after cell death has occurred. While morphological and biochemical evidence shows that autophagy is clearly present it is not responsible for the observed cell death. There are a number of features consistent with paraptosis including morphology, caspase-independence, and the requirement for new protein synthesis. However in contrast to some reports of paraptosis, the activation of JNK signaling was not required for everolimus-induced cell death. Overall in acute lymphoblastic leukemia cells everolimus induces a cell death that resembles paraptosis. PMID:25014496

  10. mTOR Inhibition by Everolimus in Childhood Acute Lymphoblastic Leukemia Induces Caspase-Independent Cell Death

    PubMed Central

    Baraz, Rana; Cisterne, Adam; Saunders, Philip O.; Hewson, John; Thien, Marilyn; Weiss, Jocelyn; Basnett, Jordan; Bradstock, Kenneth F.; Bendall, Linda J.

    2014-01-01

    Increasingly, anti-cancer medications are being reported to induce cell death mechanisms other than apoptosis. Activating alternate death mechanisms introduces the potential to kill cells that have defects in their apoptotic machinery, as is commonly observed in cancer cells, including in hematological malignancies. We, and others, have previously reported that the mTOR inhibitor everolimus has pre-clinical efficacy and induces caspase-independent cell death in acute lymphoblastic leukemia cells. Furthermore, everolimus is currently in clinical trial for acute lymphoblastic leukemia. Here we characterize the death mechanism activated by everolimus in acute lymphoblastic leukemia cells. We find that cell death is caspase-independent and lacks the morphology associated with apoptosis. Although mitochondrial depolarization is an early event, permeabilization of the outer mitochondrial membrane only occurs after cell death has occurred. While morphological and biochemical evidence shows that autophagy is clearly present it is not responsible for the observed cell death. There are a number of features consistent with paraptosis including morphology, caspase-independence, and the requirement for new protein synthesis. However in contrast to some reports of paraptosis, the activation of JNK signaling was not required for everolimus-induced cell death. Overall in acute lymphoblastic leukemia cells everolimus induces a cell death that resembles paraptosis. PMID:25014496

  11. Potentiation of Growth Inhibitory Responses of the mTOR Inhibitor Everolimus by Dual mTORC1/2 Inhibitors in Cultured Breast Cancer Cell Lines

    PubMed Central

    Leung, Euphemia Y.; Askarian-Amiri, Marjan; Finlay, Graeme J.; Rewcastle, Gordon W.; Baguley, Bruce C.

    2015-01-01

    The mammalian target of rapamycin (mTOR), a vital component of signaling pathways involving PI3K/AKT, is an attractive therapeutic target in breast cancer. Everolimus, an allosteric mTOR inhibitor that inhibits the mTOR functional complex mTORC1, is approved for treatment of estrogen receptor positive (ER+) breast cancer. Other mTOR inhibitors show interesting differences in target specificities: BEZ235 and GSK2126458 are ATP competitive mTOR inhibitors targeting both PI3K and mTORC1/2; AZD8055, AZD2014 and KU-0063794 are ATP competitive mTOR inhibitors targeting both mTORC1 and mTORC2; and GDC-0941 is a pan-PI3K inhibitor. We have addressed the question of whether mTOR inhibitors may be more effective in combination than singly in inhibiting the proliferation of breast cancer cells. We selected a panel of 30 human breast cancer cell lines that included ER and PR positive, HER2 over-expressing, and “triple negative” variants, and determined whether signaling pathway utilization was related to drug-induced inhibition of proliferation. A significant correlation (p = 0.005) was found between everolimus IC50 values and p70S6K phosphorylation, but not with AKT or ERK phosphorylation, consistent with the mTOR pathway being a principal target. We then carried out combination studies with four everolimus resistant triple-negative breast cancer cell lines, and found an unexpectedly high degree of synergy between everolimus and the other inhibitors tested. The level of potentiation of everolimus inhibitory activity (measured by IC50 values) was found to be cell line-specific for all the kinase inhibitors tested. The results suggest that judicious combination of mTOR inhibitors with different modes of action could have beneficial effects in the treatment of breast cancer. PMID:26148118

  12. Beneficial Effects of the mTOR Inhibitor Everolimus in Patients with Advanced Medullary Thyroid Carcinoma: Subgroup Results of a Phase II Trial

    PubMed Central

    Schneider, T. C.; de Wit, D.; Links, T. P.; van Erp, N. P.; van der Hoeven, J. J. M.; Gelderblom, H.; van Wezel, T.; van Eijk, R.; Morreau, H.; Guchelaar, H. J.; Kapiteijn, E.

    2015-01-01

    Objective. Until recently, advanced medullary thyroid cancer (MTC) had few treatment options except surgery. The mTOR inhibitor everolimus has shown encouraging results in neuroendocrine tumors. As part of a prospective phase II study, we analyzed the safety and efficacy of everolimus in advanced MTC. Methods. Seven patients with per RECIST 1.1 documented advanced MTC were included and received everolimus 10 mg daily. The primary objective was determining treatment efficacy. Secondary endpoints included progression-free survival (PFS), overall survival (OS), toxicity, and pharmacokinetics (PK). Results. Median follow-up duration was 28 weeks (17–147). Five patients (71%) showed SD, of which 4 (57%) showed SD >24 weeks. Median PFS and OS were 33 (95%CI: 8–56) and 30 (95%CI: 15–45) weeks, respectively. Toxicity was predominantly grade 1/2 and included mucositis (43%), fatigue (43%), and hypertriglyceridemia (43%). Four MTCs harbored the somatic RET mutation c.2753T>C, p.Met918Thr. The best clinical response was seen in a MEN2A patient. PK characteristics were consistent with phase I data. One patient exhibited extensive toxicity accompanying elevated everolimus plasma concentrations. Conclusions. This study suggests that everolimus exerts clinically relevant antitumor activity in patients with advanced MTC. Given the high level of clinical benefit and the relatively low toxicity profile, further investigation of everolimus in these patients is warranted. PMID:26294908

  13. RAD001 (everolimus) attenuates experimental autoimmune neuritis by inhibiting the mTOR pathway, elevating Akt activity and polarizing M2 macrophages.

    PubMed

    Han, Ranran; Gao, Juan; Zhai, Hui; Xiao, Jinting; Ding, Ya'nan; Hao, Junwei

    2016-06-01

    Guillain-Barre' syndrome (GBS) is an acute, postinfectious, immune-mediated, demyelinating disease of peripheral nerves and nerve roots. As a classical animal model of GBS, experimental autoimmune neuritis (EAN) has become well-accepted. Additionally, the potent immune modulation exerted by mammalian target of rapamycin (mTOR) inhibitors has been used to treat cancers and showed beneficial effects. Here we demonstrate that the mTOR inhibitor RAD001 (everolimus) protected rats from the symptoms of EAN, as shown by decreased paralysis, diminished inflammatory cell infiltration, reductions in demyelination of peripheral nerves and improved nerve conduction. Furthermore, RAD001 shifted macrophage polarization toward the protective M2 phenotype and modified the inflammatory milieu by downregulating the production of pro-inflammatory cytokines including IFN-γ and IL-17as well as upregulating the release of anti-inflammatory cytokines such as IL-4 and TGF-β. Amounts of the mTOR downstream targets p-P70S6K and p-4E-BP1 in sciatic nerves decreased, whereas the level of its upstream protein p-Akt was elevated. This demonstrated that RAD001 inhibited the mTOR pathway and encouraged the expression of p-Akt, which led to M2 macrophage polarization, thus improved the outcome of EAN in rats. Consequently, RAD001 exhibits strong potential as a therapeutic strategy for ameliorating peripheral poly-neuropathy. PMID:27063582

  14. Everolimus inhibits anti-HLA I antibody-mediated endothelial cell signaling, migration and proliferation more potently than sirolimus.

    PubMed

    Jin, Y-P; Valenzuela, N M; Ziegler, M E; Rozengurt, E; Reed, E F

    2014-04-01

    Antibody (Ab) crosslinking of HLA I molecules on the surface of endothelial cells triggers proliferative and pro-survival intracellular signaling, which is implicated in the process of chronic allograft rejection, also known as transplant vasculopathy (TV). The purpose of this study was to investigate the role of mammalian target of rapamycin (mTOR) in HLA I Ab-induced signaling cascades. Everolimus provides a tool to establish how the mTOR signal network regulates HLA I-mediated migration, proliferation and survival. We found that everolimus inhibits mTOR complex 1 (mTORC1) by disassociating Raptor from mTOR, thereby preventing class I-induced phosphorylation of mTOR, p70S6K, S6RP and 4E-BP1, and resultant class I-stimulated cell migration and proliferation. Furthermore, we found that everolimus inhibits class I-mediated mTORC2 activation (1) by disassociating Rictor and Sin1 from mTOR; (2) by preventing class I-stimulated Akt phosphorylation and (3) by preventing class I-mediated ERK phosphorylation. These results suggest that everolimus is more effective than sirolimus at antagonizing both mTORC1 and mTORC2, the latter of which is critical in endothelial cell functional changes leading to TV in solid organ transplantation after HLA I crosslinking. Our findings point to a potential therapeutic effect of everolimus in prevention of chronic Ab-mediated rejection. PMID:24580843

  15. FINAL RESULTS OF A PROSPECTIVE MULTI-INSTITUTIONAL PHASE II STUDY OF EVEROLIMUS (RAD001), AN MTOR INHIBITOR, IN PEDIATRIC PATIENTS WITH RECURRENT OR PROGRESSIVE LOW-GRADE GLIOMA. A POETIC CONSORTIUM TRIAL

    PubMed Central

    Kieran, Mark W.; Yao, X.; Macy, M.; Leary, S.; Cohen, K.; MacDonald, T.; Allen, J.; Boklan, J.; Smith, A.; Nazemi, K.; Gore, L.; Trippett, T.; DiRenzo, J.; Narendran, A.; Perentesis, J.; Prabhu, S.; Pinches, N.; Robison, N.; Manley, P.; Chi, S.

    2014-01-01

    BACKGROUND: Purpose: The ras/raf signaling pathway is crucial in the development of pediatric low-grade gliomas (LGGs). Aberrant ras/raf signaling is involved in tumorigenesis through promotion of cell proliferation, survival, and differentiation in sporadic LGG. Everolimus (RAD001) is a potent and selective inhibitor of mTOR, a downstream element of the ras/raf pathway. The activity, safety and pharmacokinetics of everolimus in pediatric patients with radiographic recurrent/progressive LGG are presented. METHODS: Pediatric patients with radiographic progressive or recurrent LGGs without neurofibromatosis type I were treated with oral everolimus 5mg/m2/dose once daily. Therapy was provided for 28 days (one cycle) and could be repeated for a total of 12 cycles. Response, as determined by standard 2-D MRI criteria, was assessed for all patients. Pharmacokinetics, pharmacogenetics, pharmacodynamic parameters including inhibition of p70s6 kinase activity, 4E-BP1 phosphorylation inhibition and suppression of cMyc expression, as well as the toxicity profile of everolimus were evaluated. RESULTS: Twenty-three patients with a median age of 9 years (range, 3–17 years) were enrolled, all of whom had received prior chemotherapy (average # regimens = 2.7) including progression after a carboplatin-containing regimen. Median number of cycles of therapy was 10 (range, 1-12). Responses were determined by blinded central review and included 4 patients with PR (>50% decrease) and 13 with stable disease. Six patients had progressive disease by one year. Overall therapy was well tolerated; two patients discontinued therapy due to mouth sores (n = 1) and withdrawal of consent (n = 1). Everolimus PK parameters were similar to those previously reported in both adult and pediatric patients and drug trough levels were maintained above 5ng/ml. Pharmacodynamic analysis demonstrated inhibition of downstream targets of mTOR including phospho-S6 kinase, 4E-BP1 phosphorylation and c

  16. Response and Acquired Resistance to Everolimus in Anaplastic Thyroid Cancer

    PubMed Central

    Wagle, Nikhil; Grabiner, Brian C.; Van Allen, Eliezer M.; Amin-Mansour, Ali; Taylor-Weiner, Amaro; Rosenberg, Mara; Gray, Nathanael; Barletta, Justine A.; Guo, Yanan; Swanson, Scott J.; Ruan, Daniel T.; Hanna, Glenn J.; Haddad, Robert I.; Getz, Gad; Kwiatkowski, David J.; Carter, Scott L.; Sabatini, David M.; Jänne, Pasi A.; Garraway, Levi A.; Lorch, Jochen H.

    2015-01-01

    SUMMARY Everolimus, an inhibitor of the mammalian target of rapamycin (mTOR), is effective in treating tumors harboring alterations in the mTOR pathway. Mechanisms of resistance to everolimus remain undefined. Resistance developed in a patient with metastatic anaplastic thyroid carcinoma after an extraordinary 18-month response. Whole-exome sequencing of pretreatment and drug-resistant tumors revealed a nonsense mutation in TSC2, a negative regulator of mTOR, suggesting a mechanism for exquisite sensitivity to everolimus. The resistant tumor also harbored a mutation in MTOR that confers resistance to allosteric mTOR inhibition. The mutation remains sensitive to mTOR kinase inhibitors. PMID:25295501

  17. Use of everolimus in liver transplantation: The French experience.

    PubMed

    Dumortier, Jérôme; Dharancy, Sebastien; Calmus, Yvon; Duvoux, Christophe; Durand, François; Salamé, Ephrem; Saliba, Faouzi

    2016-07-01

    The mammalian target of rapamycin (mTOR) inhibitor everolimus is approved for rejection prophylaxis after liver transplantation. The current article pools the experience of French liver transplant surgeons and physicians in use of everolimus and, particularly, practical guidance on dosing, appropriate concomitant immunosuppression and management of adverse events. In terms of indication, introduction of everolimus from week 4 after liver transplantation, with or without concomitant calcineurin inhibitor (CNI) therapy, offers a significant renal benefit without loss of immunosuppressive efficacy. De novo treatment with everolimus, either selectively or systematically, may play a role in the prevention and treatment of recurrence of hepatocellular cancer and de novo malignancies. For maintenance patients, the most frequent indications for introducing everolimus are in response to renal dysfunction, recurrent hepatocellular cancer, diabetes, hypertension, or neurotoxicity, or as a preventative approach to avoid malignancies. Of these, the strongest evidence exists for a renoprotective effect. However, the low rate of acute rejection following switch of maintenance patients from CNI-based to everolimus-based therapy means that this can be considered even where robust data are not yet available. Most adverse events associated with mTOR inhibitors can usually be managed successfully, often with concentration-controlled dose reductions. Dosing algorithms are provided, with suggestions for target ranges in specific settings, and treatment strategies for the most common side effects are proposed. Although further research is required, everolimus has become an established part of the immunosuppressive arsenal for liver transplant recipients over the last decade. Sharing experience from units which have embraced its use may help other centers develop their own protocols. PMID:27083870

  18. Profile of everolimus in the treatment of tuberous sclerosis complex: an evidence-based review of its place in therapy.

    PubMed

    Capal, Jamie K; Franz, David Neal

    2016-01-01

    Tuberous sclerosis complex (TSC) is a relatively rare genetic disorder, affecting one in 6,000 births. Mammalian target of rapamycin (mTOR) inhibitors, such as everolimus, which have been previously used to prevent solid organ transplant rejection, augment anticancer treatment regimens, and prevent neovascularization of artificial cardiac stents, are now approved for treating TSC-related manifestations, such as subependymal giant cell astrocytomas and renal angiomyolipomas. The use of everolimus in treating subependymal giant cell astrocytomas is supported by long-term Phase II and III clinical trials. Seizures are a common feature in TSC, occurring in up to 96% of patients. While mTOR inhibitors currently do not have regulatory approval in treating this manifestation, small clinical studies have demonstrated beneficial outcomes with everolimus. Further evidence from a forthcoming Phase III clinical study may provide additional support for the use of everolimus for this indication. Also, there are no approved treatments for TSC-associated neuropsychiatric disorders, which include intellectual disability, behavioral difficulties, and autism spectrum disorder, but preclinical data and small studies have suggested that some neuropsychiatric symptoms may be improved through mTOR inhibition therapy. More evidence is needed, particularly regarding safety in young infants. This review focuses on the current evidence supporting the use of everolimus in neurologic and neuropsychiatric manifestations of TSC, and the place of everolimus in therapy. PMID:27601910

  19. Profile of everolimus in the treatment of tuberous sclerosis complex: an evidence-based review of its place in therapy

    PubMed Central

    Capal, Jamie K; Franz, David Neal

    2016-01-01

    Tuberous sclerosis complex (TSC) is a relatively rare genetic disorder, affecting one in 6,000 births. Mammalian target of rapamycin (mTOR) inhibitors, such as everolimus, which have been previously used to prevent solid organ transplant rejection, augment anticancer treatment regimens, and prevent neovascularization of artificial cardiac stents, are now approved for treating TSC-related manifestations, such as subependymal giant cell astrocytomas and renal angiomyolipomas. The use of everolimus in treating subependymal giant cell astrocytomas is supported by long-term Phase II and III clinical trials. Seizures are a common feature in TSC, occurring in up to 96% of patients. While mTOR inhibitors currently do not have regulatory approval in treating this manifestation, small clinical studies have demonstrated beneficial outcomes with everolimus. Further evidence from a forthcoming Phase III clinical study may provide additional support for the use of everolimus for this indication. Also, there are no approved treatments for TSC-associated neuropsychiatric disorders, which include intellectual disability, behavioral difficulties, and autism spectrum disorder, but preclinical data and small studies have suggested that some neuropsychiatric symptoms may be improved through mTOR inhibition therapy. More evidence is needed, particularly regarding safety in young infants. This review focuses on the current evidence supporting the use of everolimus in neurologic and neuropsychiatric manifestations of TSC, and the place of everolimus in therapy. PMID:27601910

  20. Inhibition of Chondrosarcoma Growth by mTOR Inhibitor in an In Vivo Syngeneic Rat Model

    PubMed Central

    Perez, Jennifer; Decouvelaere, Anne Valérie; Pointecouteau, Thomas; Pissaloux, Daniel; Michot, Jean Philippe; Besse, Anthony; Blay, Jean Yves; Dutour, Aurélie

    2012-01-01

    Background Chondrosarcomas are the second most frequent primary malignant type of bone tumor. No effective systemic treatment has been identified in advanced or adjuvant phases for chondrosarcoma. The aim of the present study was to determine the antitumor effects of doxorubicin and everolimus, an mTOR inhibitor on chondrosarcoma progression. Methods and Findings Doxorubin and/or everolimus were tested in vivo as single agent or in combination in the rat orthotopic Schwarm chondrosarcoma model, in macroscopic phase, as well as with microscopic residual disease. Response to everolimus and/or doxorubicin was evaluated using chondrosarcoma volume evolution (MRI). Histological response was evaluated with % of tumor necrosis, tumor proliferation index, metabolism quantification analysis between the treated and control groups. Statistical analyses were performed using chi square, Fishers exact test. Doxorubicin single agent has no effect of tumor growth as compared to no treatment; conversely, everolimus single agent significantly inhibited tumor progression in macroscopic tumors with no synergistic additive effect with doxorubicin. Everolimus inhibited chondrosarcoma proliferation as evaluated by Ki67 expression did not induce the apoptosis of tumor cells; everolimus reduced Glut1 and 4EBP1 expression. Importantly when given in rats with microscopic residual diseases, in a pseudo neoadjuvant setting, following R1 resection of the implanted tumor, everolimus significantly delayed or prevented tumor recurrence. Conclusions MTOR inhibitor everolimus blocks cell proliferation, Glut1 expression and HIF1a expression, and prevents in vivo chondrosarcoma tumor progression in both macroscopic and in adjuvant phase post R1 resection. Taken together, our preclinical data indicate that mTOR inhibitor may be effective as a single agent in treating chondrosarcoma patients. A clinical trial evaluating mTOr inhibitor as neo-adjuvant and adjuvant therapy in chondrosarcoma patients is

  1. Dosing and Safety Implications for Oncologists When Administering Everolimus to Patients With Hormone Receptor-Positive Breast Cancer.

    PubMed

    Rugo, Hope S

    2016-02-01

    Aberrations in the phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin pathway are common abnormalities in breast cancer and are associated with the development of resistance to endocrine- and human epidermal growth factor receptor (HER)2-targeted therapies. Because of the significant improvement in progression-free survival for everolimus plus exemestane compared with exemestane plus placebo, everolimus, an mTOR inhibitor, was approved in the United States for the treatment of patients with hormone receptor-positive (HR+), HER-negative, advanced breast cancer whose disease had progressed while receiving letrozole or anastrozole. To provide optimal prevention and management strategies, it is crucial that clinicians are aware of the adverse events (AEs) associated with mTOR inhibition. Understanding the appropriate dose modifications will help reduce toxicity and improve drug tolerance, thus achieving the optimal benefit from everolimus. Analyses of data from the Breast Cancer Trials of Oral Everolimus 2 trial have shown that, despite a greater frequency of AEs in the everolimus plus exemestane treatment arm, the AEs were effectively managed with temporary dose reductions or interruptions. In some cases, the full dose of everolimus could be resumed. Despite a lower mean dose and duration of exposure in patients aged ≥ 70 versus < 70 years, everolimus plus exemestane was similarly efficacious, suggesting that appropriate dose reductions for toxicity will not adversely impact efficacy. Appropriate modification of the everolimus dose and dose delay according to the severity of AEs, with resumption of the optimal dose of everolimus when toxicity has improved, will positively affect patient outcomes in HR+ advanced breast cancer. PMID:26507507

  2. Systemic and CNS activity of the RET inhibitor vandetanib combined with the mTOR inhibitor everolimus in KIF5B-RET re-arranged non-small cell lung cancer with brain metastases.

    PubMed

    Subbiah, Vivek; Berry, Jenny; Roxas, Michael; Guha-Thakurta, Nandita; Subbiah, Ishwaria Mohan; Ali, Siraj M; McMahon, Caitlin; Miller, Vincent; Cascone, Tina; Pai, Shobha; Tang, Zhenya; Heymach, John V

    2015-07-01

    In-frame fusion KIF5B (the-kinesin-family-5B-gene)-RET transcripts have been characterized in 1-2% of non-small cell lung cancers and are known oncogenic drivers. The RET tyrosine kinase inhibitor, vandetanib, suppresses fusion-induced, anchorage-independent growth activity. In vitro studies have shown that vandetanib is a high-affinity substrate of breast cancer resistance protein (Bcrp1/Abcg2) but is not transported by P-glycoprotein (P-gp), limiting its blood-brain barrier penetration. A co-administration strategy to enhance the brain accumulation of vandetanib by modulating P-gp/Abcb1- and Bcrp1/Abcg2-mediated efflux with mTOR inhibitors, specifically everolimus, was shown to increase the blood-brain barrier penetration. We report the first bench-to-bedside evidence that RET inhibitor combined with an mTOR inhibitor is active against brain-metastatic RET-rearranged lung cancer and the first evidence of blood-brain barrier penetration. A 74-year-old female with progressive adenocarcinoma of the lung (wild-type EGFR and no ALK rearrangement) presented for therapy options. A deletion of 5'RET was revealed by FISH assay, indicating RET-gene rearrangement. Because of progressive disease in the brain, she was enrolled in a clinical trial with vandetanib and everolimus (NCT01582191). Comprehensive genomic profiling revealed fusion of KIF5B (the-kinesin-family-5B-gene) and RET, in addition to AKT2 gene amplification. After two cycles of therapy a repeat MRI brain showed a decrease in the intracranial disease burden and PET/CT showed systemic response as well. Interestingly, AKT2 amplification seen is a critical component of the PI3K/mTOR pathway, alterations of which has been associated with both de novo and acquired resistance to targeted therapy. The addition of everolimus may have both overcome the AKT2 amplification to produce a response in addition to its direct effects on the RET gene. Our case report forms the first evidence of blood-brain barrier penetration by

  3. Systemic and CNS activity of the RET inhibitor vandetanib combined with the mTOR inhibitor everolimus in KIF5B-RET re-arranged Non-Small Cell Lung Cancer with brain metastases

    PubMed Central

    Subbiah, Vivek; Berry, Jenny; Roxas, Michael; Guha-Thakurta, Nandita; Subbiah, Ishwaria Mohan; Ali, Siraj M.; McMahon, Caitlin; Miller, Vincent; Cascone, Tina; Pai, Shobha; Tang, Zhenya; Heymach, John V.

    2016-01-01

    In-frame fusion KIF5B (the-kinesin-family-5B-gene)-RET transcripts have been characterized in 1–2% of non-small cell lung cancers and are known oncogenic drivers. The RET tyrosine kinase inhibitor, vandetanib, suppresses fusion-induced, anchorage-independent growth activity. In vitro studies have shown that vandetanib is a high-affinity substrate of breast cancer resistance protein (Bcrp1/Abcg2) but is not transported by P-glycoprotein (P-gp), limiting its blood-brain barrier penetration. A co-administration strategy to enhance the brain accumulation of vandetanib by modulating P-gp/Abcb1- and Bcrp1/Abcg2-mediated efflux with mTOR inhibitors, specifically everolimus, was shown to increase the blood-brain barrier penetration. We report the first bench to bed-side evidence that RET inhibitor combined with an mTOR inhibitor is active against brain-metastatic RET-rearranged lung cancer and the first evidence of blood-brain barrier penetration. A 74 year old female with progressive adenocarcinoma of the lung (wild-type EGFR and no ALK rearrangement) presented for therapy options. A deletion of 5’RET was revealed by FISH assay, indicating RET-gene rearrangement. Because of progressive disease in the brain, she was enrolled in a clinical trial with vandetanib and everolimus (NCT01582191). Comprehensive genomic profiling revealed fusion of KIF5B (the-kinesin-family-5B-gene) and RET, in addition to AKT2 gene amplification. After 2 cycles of therapy a repeat MRI brain showed a decrease in the intracranial disease burden and PET /CT showed systemic response as well. Interestingly, AKT2 amplification seen is a critical component of the PI3K/mTOR pathway, alterations of which has been associated with both de novo and acquired resistance to targeted therapy. The addition of everolimus may have both overcome the AKT2 amplification to produce a response in addition to its direct effects on the RET gene. Our case report forms the first evidence of blood

  4. Regression of Cardiac Rhabdomyomas in a Neonate after Everolimus Treatment

    PubMed Central

    Bornaun, Helen; Öztarhan, Kazım; Erener-Ercan, Tugba; Dedeoğlu, Reyhan; Tugcu, Deniz; Aydoğmuş, Çiğdem; Cetinkaya, Merih; Kavuncuoglu, Sultan

    2016-01-01

    Cardiac rhabdomyoma often shows spontaneous regression and usually requires only close follow-up. However, patients with symptomatic inoperable rhabdomyomas may be candidates for everolimus treatment. Our patient had multiple inoperable cardiac rhabdomyomas causing serious left ventricle outflow-tract obstruction that showed a dramatic reduction in the size after everolimus therapy, a mammalian target of rapamycin (mTOR) inhibitor. After discontinuation of therapy, an increase in the diameter of masses occurred and everolimus was restarted. After 6 months of treatment, rhabdomyomas decreased in size and therapy was stopped. In conclusion, everolimus could be a possible novel therapy for neonates with clinically significant rhabdomyomas. PMID:27429821

  5. Age-Related Neurodegeneration Prevention Through mTOR Inhibition: Potential Mechanisms and Remaining Questions

    PubMed Central

    Jahrling, Jordan B.; Laberge, Remi-Martin

    2016-01-01

    With the global aging population, Alzheimer's disease, Parkinson's disease and mild cognition impairment are increasing in prevalence. The success of rapamycin as an agent to extend lifespan in various organisms, including mice, brings hope that chronic mTOR inhibition could also refrain age-related neurodegeneration. Here we review the evidence suggesting that mTOR inhibition - mainly with rapamycin - is a valid intervention to delay age-related neurodegeneration. We discuss the potential mechanisms by which rapamycin may facilitate neurodegeneration prevention or restoration of cognitive function. We also discuss the known side effects of rapamycin and provide evidence to alleviate exaggerated concerns regarding its wider clinical use. We explore the small molecule alternatives to rapamycin and propose future directions for their development, mainly by exploring the possibility of targeting the downstream effectors of mTOR: S6K1 and especially S6K2. Finally, we discuss the strengths and weaknesses of the models used to determine intervention efficacy for neurodegeneration. We address the difficulties of interpreting data using the common way of investigating the efficacy of interventions to delay/prevent neurodegeneration by observing animal behavior while these animals are under treatment. We propose an experimental design that should isolate the variable of aging in the experimental design and resolve the ambiguity present in recent literature. PMID:26059360

  6. Meta-analysis of stomatitis in clinical studies of everolimus: incidence and relationship with efficacy

    PubMed Central

    Rugo, H. S.; Hortobagyi, G. N.; Yao, J.; Pavel, M.; Ravaud, A.; Franz, D.; Ringeisen, F.; Gallo, J.; Rouyrre, N.; Anak, O.; Motzer, R.

    2016-01-01

    Background Everolimus, an oral mammalian target of rapamycin (mTOR) inhibitor, is used to treat solid tumors and tuberous sclerosis complex (TSC). Stomatitis, an inflammation of the mucous membranes of the mouth, is a common adverse event associated with mTOR inhibitors, including everolimus. We conducted a meta-analysis of data from seven randomized, double-blind phase 3 clinical trials of everolimus to determine the clinical impact of stomatitis on efficacy and safety. Patients and methods Data were pooled from the safety sets of solid tumor [breast cancer (BOLERO-2 and BOLERO-3), renal cell carcinoma (RECORD-1), carcinoid tumors (RADIANT-2), and pancreatic neuroendocrine tumors (RADIANT-3)] and TSC studies (EXIST-1 and EXIST-2). Data from solid tumor trials and TSC trials were analyzed separately. Results The rate of stomatitis was 67% in the solid tumor trials (973/1455 patients) and 70% in the TSC trials (110/157 patients). Most stomatitis events were grade 1/2, with grade 3/4 events reported in only 9% (solid tumor trials) and 8% (TSC trials) of patients. Low TSC patient numbers prevented an in-depth evaluation of stomatitis and response. In the solid tumor trials, most first stomatitis episodes (89%; n = 870) were observed within 8 weeks of starting everolimus. Patients with stomatitis occurring within 8 weeks of everolimus initiation had longer progression-free survival (PFS) than everolimus-treated patients without stomatitis in BOLERO-2 {8.5 versus 6.9 months, respectively; hazard ratio (HR), 0.78 [95% confidence interval (CI), 0.62–1.00]} and RADIANT-3 [13.9 versus 8.3 months, respectively; HR, 0.70 (95% CI, 0.48–1.04)]. A similar trend was observed in RECORD-1 [HR, 0.90 (95% CI, 0.66–1.22)] and RADIANT-2 [HR, 0.87 (95% CI, 0.61–1.22)] but not in BOLERO-3 [HR, 1.01 (95% CI, 0.75–1.36)]. Conclusions Stomatitis did not adversely affect PFS, supporting the administration of everolimus in accordance with standard management guidelines. PMID

  7. Inhibition of mTOR by apigenin in UVB-irradiated keratinocytes: A new implication of skin cancer prevention.

    PubMed

    Bridgeman, Bryan B; Wang, Pu; Ye, Boping; Pelling, Jill C; Volpert, Olga V; Tong, Xin

    2016-05-01

    Ultraviolet B (UVB) radiation is the major environmental risk factor for developing skin cancer, the most common cancer worldwide, which is characterized by aberrant activation of Akt/mTOR (mammalian target of rapamycin). Importantly, the link between UV irradiation and mTOR signaling has not been fully established. Apigenin is a naturally occurring flavonoid that has been shown to inhibit UV-induced skin cancer. Previously, we have demonstrated that apigenin activates AMP-activated protein kinase (AMPK), which leads to suppression of basal mTOR activity in cultured keratinocytes. Here, we demonstrated that apigenin inhibited UVB-induced mTOR activation, cell proliferation and cell cycle progression in mouse skin and in mouse epidermal keratinocytes. Interestingly, UVB induced mTOR signaling via PI3K/Akt pathway, however, the inhibition of UVB-induced mTOR signaling by apigenin was not Akt-dependent. Instead, it was driven by AMPK activation. In addition, mTOR inhibition by apigenin in keratinocytes enhanced autophagy, which was responsible, at least in part, for the decreased proliferation in keratinocytes. In contrast, apigenin did not alter UVB-induced apoptosis. Taken together, our results indicate the important role of mTOR inhibition in UVB protection by apigenin, and provide a new target and strategy for better prevention of UV-induced skin cancer. PMID:26876613

  8. Interstitial Lung Disease Associated with mTOR Inhibitors in Solid Organ Transplant Recipients: Results from a Large Phase III Clinical Trial Program of Everolimus and Review of the Literature.

    PubMed

    Lopez, Patricia; Kohler, Sven; Dimri, Seema

    2014-01-01

    Interstitial lung disease (ILD) has been reported with the use of mammalian target of rapamycin inhibitors (mTORi). The clinical and safety databases of three Phase III trials of everolimus in de novo kidney (A2309), heart (A2310), and liver (H2304) transplant recipients (TxR) were searched using a standardized MedDRA query (SMQ) search for ILD followed by a case-by-case medical evaluation. A literature search was conducted in MEDLINE and EMBASE. Out of the 1,473 de novo TxR receiving everolimus in Phase III trials, everolimus-related ILD was confirmed in six cases (one kidney, four heart, and one liver TxR) representing an incidence of 0.4%. Everolimus was discontinued in three of the four heart TxR, resulting in ILD improvement or resolution. Outcome was fatal in the kidney TxR (in whom everolimus therapy was continued) and in the liver TxR despite everolimus discontinuation. The literature review identified 57 publications on ILD in solid organ TxR receiving everolimus or sirolimus. ILD presented months or years after mTORi initiation and symptoms were nonspecific and insidious. The event was more frequent in patients with a late switch to mTORi. In most cases, ILD was reversed after prompt mTORi discontinuation. ILD induced by mTORi is an uncommon and potentially fatal event warranting early recognition and drug discontinuation. PMID:25580277

  9. Evaluation of oral care to prevent oral mucositis in estrogen receptor-positive metastatic breast cancer patients treated with everolimus (Oral Care-BC): randomized controlled phase III trial.

    PubMed

    Niikura, Naoki; Ota, Yoshihide; Hayashi, Naoki; Naito, Mariko; Kashiwabara, Kosuke; Watanabe, Ken-Ichi; Yamashita, Toshinari; Mukai, Hirofumi; Umeda, Masahiro

    2016-09-01

    This is a randomized, multi-center, open-label, phase III study to evaluate the efficacy of professional oral care in preventing oral mucositis induced by everolimus in postmenopausal estrogen receptor-positive metastatic breast cancer. Patients will be randomized into professional oral care and control groups (1:1 ratio). All patients will receive everolimus with exemestane and will continue everolimus until disease progression. In the professional oral care group, patients will receive teeth surface cleaning, scaling and tongue cleaning before starting everolimus, and will continue to receive professional oral care weekly from oral surgeons throughout the 8 week treatment. In the control group, patients will brush their own teeth and gargle with 0.9% sodium chloride solution or water. The primary endpoint is the incidence of all grades of oral mucositis. Target accrual is 200 patients with a two-sided type I error rate of 5% and 80% power to detect 25% risk reduction. PMID:27365521

  10. Everolimus exhibits efficacy as a radiosensitizer in a model of non-small cell lung cancer.

    PubMed

    Mauceri, Helena J; Sutton, Harold G; Darga, Thomas E; Kocherginsky, Masha; Kochanski, Joel; Weichselbaum, Ralph R; Vokes, Everett E

    2012-05-01

    Signaling pathways that activate mTOR (mammalian target of rapamycin) are altered in many human cancers and these alterations are associated with prognosis and treatment response. mTOR inhibition can restore sensitivity to DNA damaging agents such as cisplatin. The rapamycin derivative everolimus exhibits antitumor activity and is approved for patients with renal cell cancer. Clinically, everolimus has also been evaluated in patients with advanced non-small cell lung cancer (NSCLC) that were refractory to chemotherapy and epidermal growth factor receptor tyrosine kinase inhibitors. We tested the effects of combined treatment with everolimus (RAD001) and fractionated radiation using a xenograft model of human NSCLC (A549 cells). In growth studies, mean tumor volume was reduced in the everolimus plus 30 Gy cohort with significant tumor growth suppression compared to 30 Gy alone (p=0015), or everolimus alone (p<0.001, ANOVA). everolimus (20 nM) significantly reduced protein levels of the mTOR downstream effector p70-S6K compared with radiation and vehicle (p=0.05, ANOVA) and significantly suppressed phospho-p70-S6K levels compared with all other treatments (p<0.001, ANOVA). We also evaluated everolimus and radiation effects on gene expression in A549 cells. Everolimus ± 5 Gy suppressed endothelin 1 and lactate dehydrogenase expression and increased VEGFA, p21, hypoxia-inducible factor-1α and SLC2A1 (facilitated glucose transporter 1). mTOR mRNA levels were unaffected while TNF-α levels were increased with everolimus + 5 Gy compared to either treatment alone. These findings suggest that everolimus increases the antitumor activity of radiation. Clinical trials combining everolimus with fractionated radiation in patients with NSCLC are warranted. PMID:22294050

  11. Combined treatment by octreotide and everolimus: Octreotide enhances inhibitory effect of everolimus in aggressive meningiomas.

    PubMed

    Graillon, Thomas; Defilles, Céline; Mohamed, Amira; Lisbonis, Christophe; Germanetti, Anne-Laure; Chinot, Olivier; Figarella-Branger, Dominique; Roche, Pierre-Hugues; Adetchessi, Tarek; Fuentes, Stéphane; Metellus, Philippe; Dufour, Henry; Enjalbert, Alain; Barlier, Anne

    2015-08-01

    Treatment for recurrent and aggressive meningiomas remains an unmet medical need in neuro-oncology, and chemotherapy exhibits limited clinical activity, if any. Merlin expression, encoded by the NF2 gene, is lost in a majority of meningiomas, and merlin is a negative regulator of mTORC1. The sst2 somatostatin receptor, targeted by octreotide, is highly expressed in meningiomas. To investigate new therapeutic strategies, we evaluated the activity of everolimus (mTOR inhibitor), BKM-120 and BEZ-235 (new Pi3K/Akt/mTOR inhibitors), octreotide and a combined treatment (octreotide plus everolimus), on cell proliferation, signaling pathways, and cell cycle proteins, respectively. The in vitro study was conducted on human meningioma primary cells extracted from fresh tumors, allowing the assessment of somatostatin analogs at the concentration levels used in patients. The results were correlated to WHO grades. Further, everolimus decreased cell viability of human meningiomas, but concomitantly, induced Akt activation, reducing the antiproliferative effect of the drug. The new Pi3K inhibitors were not more active than everolimus alone, limiting their clinical relevance. In contrast, a clear cooperative inhibitory effect of octreotide and everolimus was observed on cell proliferation in all tested meningiomas, including WHO grades II-III. Octreotide not only reversed everolimus-induced Akt phosphorylation but also displayed additive and complementary effects with everolimus on downstream proteins involved in translation (4EB-P1), and controlling cell cycle (p27Kip1 and cyclin D1). We have demonstrated a co-operative action between everolimus and octreotide on cell proliferation in human meningiomas, including aggressive ones, establishing the basis for a clinical trial. PMID:26015296

  12. Everolimus exhibits anti-tumorigenic activity in obesity-induced ovarian cancer

    PubMed Central

    Guo, Hui; Zhong, Yan; Jackson, Amanda L.; Clark, Leslie H.; Kilgore, Josh; Zhang, Lu; Han, Jianjun; Sheng, Xiugui; Gilliam, Timothy P.; Gehrig, Paola A.; Zhou, Chunxiao; Bae, Victoria L.

    2016-01-01

    Everolimus inhibits mTOR kinase activity and its downstream targets by acting on mTORC1 and has anti-tumorigenic activity in ovarian cancer. Clinical and epidemiologic data find that obesity is associated with worse outcomes in ovarian cancer. In addition, obesity leads to hyperactivation of the mTOR pathway in epithelial tissues, suggesting that mTOR inhibitors may be a logical choice for treatment in obesity-driven cancers. However, it remains unclear if obesity impacts the effect of everolimus on tumor growth in ovarian cancer. The present study was aimed at evaluating the effects of everolimus on cytotoxicity, cell metabolism, apoptosis, cell cycle, cell stress and invasion in human ovarian cancer cells. A genetically engineered mouse model of serous ovarian cancer fed a high fat diet or low fat diet allowed further investigation into the inter-relationship between everolimus and obesity in vivo. Everolimus significantly inhibited cellular proliferation, induced cell cycle G1 arrest and apoptosis, reduced invasion and caused cellular stress via inhibition of mTOR pathways in vitro. Hypoglycemic conditions enhanced the sensitivity of cells to everolimus through the disruption of glycolysis. Moreover, everolimus was found to inhibit ovarian tumor growth in both obese and lean mice. This reduction coincided with a decrease in expression of Ki-67 and phosphorylated-S6, as well as an increase in cleaved caspase 3 and phosphorylated-AKT. Metabolite profiling revealed that everolimus was able to alter tumor metabolism through different metabolic pathways in the obese and lean mice. Our findings support that everolimus may be a promising therapeutic agent for obesity-driven ovarian cancers. PMID:26959121

  13. Everolimus prolonged survival in transgenic mice with EGFR-driven lung tumors.

    PubMed

    Yasugi, Masayuki; Takigawa, Nagio; Ochi, Nobuaki; Ohashi, Kadoaki; Harada, Daijiro; Ninomiya, Takashi; Murakami, Toshi; Honda, Yoshihiro; Ichihara, Eiki; Tanimoto, Mitsune; Kiura, Katsuyuki

    2014-08-15

    Everolimus is an orally administered mTOR inhibitor. The effect, and mechanism of action, of everolimus on lung cancers with an epidermal growth factor receptor (EGFR) mutation remain unclear. Four gefitinib-sensitive and -resistant cell lines were used in the present work. Growth inhibition was determined using the MTT assay. Transgenic mice carrying the EGFR L858R mutation were treated with everolimus (10 mg/kg/day), or vehicle alone, from 5 to 20 weeks of age, and were then sacrificed. To evaluate the efficacy of everolimus in prolonging survival, everolimus (10 mg/kg/day) or vehicle was administered from 5 weeks of age. The four cell lines were similarly sensitive to everolimus. Expression of phosphorylated (p) mTOR and pS6 were suppressed upon treatment with everolimus in vitro, whereas the pAKT level increased. The numbers of lung tumors with a long axis exceeding 1mm in the everolimus-treated and control groups were 1.9 ± 0.9 and 9.4 ± 3.2 (t-test, p<0.001), respectively. pS6 was suppressed during eve r olimus treatment. Although apoptosis and autophagy were not induced in everolimus-treated EGFR transgenic mice, angiogenesis was suppressed. The median survival time in the everolimus-treated group (58.0 weeks) was significantly longer than that in the control group (31.2 weeks) (logrank test, p<0.001). These findings suggest that everolimus had an indirect effect on tumor formation by inhibiting angiogenesis and might be effective to treat lung tumors induced by an activating EGFR gene mutation. PMID:24768699

  14. A Phase I Study of Everolimus and Docetaxel in Patients With Castration-Resistant Prostate Cancer

    PubMed Central

    Courtney, Kevin D.; Manola, Judith B.; Elfiky, Aymen A.; Ross, Robert; Oh, William K.; Yap, Jeffrey T.; Van den Abbeele, Annick D.; Ryan, Christopher W.; Beer, Tomasz M.; Loda, Massimo; Priolo, Carmen; Kantoff, Philip; Taplin, Mary-Ellen

    2015-01-01

    Activation of the phosphoinositide 3-kinase signaling cascade, often through loss of the phosphatase and tensin homologue deleted on chromosome 10 (PTEN) tumor suppressor, is frequent in castration-resistant prostate cancer (CRPC). We assessed the safety and efficacy of combining the mammalian target of rapamycin (mTOR) inhibitor everolimus with docetaxel in a phase I clinical trial of men with metastatic CRPC, and evaluated the ability of fluorine–18-fluorodeoxyglucose (FDG) positron emission tomography (PET) to predict response to treatment. The observed clinical activity of tolerable dose levels of everolimus with docetaxel was low. FDG-PET might serve as a biomarker for target inhibition by mTOR inhibitors in metastatic CRPC. Background The PTEN tumor suppressor is frequently lost in CRPC, with activation of Akt-mTOR signaling, driving growth. We conducted a phase I trial of the mTOR inhibitor, everolimus, and docetaxel in CRPC. Patients and Methods Eligible patients had progressive, metastatic, chemotherapy-naive CRPC. Patients received everolimus 10 mg daily for 2 weeks and underwent a restaging FDG-PET/computed tomography scan. Patient cohorts were subsequently treated at 3 dose levels of everolimus with docetaxel: 5 mg to 60 mg/m2, 10 mg to 60 mg/m2, and 10 mg to 70 mg/m2. The primary end point was the safety and tolerability of combination therapy. Results Accrual was 4 patients at level 1, 3 patients at level 2, and 8 patients at level 3. Common toxicities were hematologic and fatigue. Serum concentrations of everolimus when administered with docetaxel were 1.5 to 14.8 ng/mL in patients receiving 5 mg everolimus and 4.5 to 55.4 ng/mL in patients receiving 10 mg everolimus. Four patients had partial metabolic response (PMR) using FDG-PET, 12 had stable metabolic disease, and 2 had progressive metabolic disease after a 2-week treatment with everolimus alone. Five of 12 evaluable patients experienced a prostate-specific antigen (PSA) reduction ≥ 50

  15. Resistance to everolimus driven by epigenetic regulation of MYC in ER+ breast cancers

    PubMed Central

    Bihani, Teeru; Ezell, Scott A.; Ladd, Brendon; Grosskurth, Shaun E.; Mazzola, Anne Marie; Pietras, Mark; Reimer, Corinne; Zinda, Michael; Fawell, Stephen; D'Cruz, Celina M.

    2015-01-01

    Acquired resistance to PI3K/mTOR/Akt pathway inhibitors is often associated with compensatory feedback loops involving the activation of oncogenes. Here, we have generated everolimus resistance in ER+ breast cancer cells and in long-term estrogen deprived (LTED) models that mimic progression on anti-estrogens. This allowed us to uncover MYC as a driver of mTOR inhibitor resistance. We demonstrate that both everolimus resistance and acute treatment of everolimus can lead to the upregulation of MYC mRNA, protein expression and, consequently, the enrichment of MYC signatures as revealed by RNA sequencing data. Depletion of MYC resulted in resensitization to everolimus, confirming its functional importance in this setting. Furthermore, ChIP assays demonstrate that MYC upregulation in the everolimus resistant lines is mediated by increased association of the BRD4 transcription factor with the MYC gene. Finally, JQ1, a BRD4 inhibitor combined with everolimus exhibited increased tumor growth inhibition in 3D Matrigel models and an in vivo xenograft model. These data suggest that MYC plays an important role in mediating resistance to everolimus in ER+ and ER+/LTED models. Furthermore, given the regulation ofMYCby BRD4 in this setting, these data have implications for increased therapeutic potential of combining epigenetic agents with mTOR inhibitors to effectively downregulate otherwise difficult to target transcription factors such as MYC. PMID:25537515

  16. Combined Use of Metformin and Everolimus Is Synergistic in the Treatment of Breast Cancer Cells.

    PubMed

    Wang, Yunshan; Wei, Junmin; Li, Li; Fan, Cong; Sun, Ying

    2014-01-01

    Everolimus inhibits mammalian target of rapamycin (mTOR) and leads to decreased protein synthesis and decreased cancer cell proliferation in many experimental systems. Adenosine 5'-monophosphate-activated protein kinase (AMPK) activators such as metformin have similar actions in keeping with the TSC2/1 pathway linking activation of AMPK to inhibition of mTOR. Histopathological and biochemical studies of breast cancer show frequent dysregulation of the AMPK and the mTOR pathway. Therefore, we investigated the efficacy of the mTOR inhibitor everolimus and metformin in the treatment of breast cancer cells. This study evaluated the in vitro and in vivo effects of everolimus alone or in combination with metformin on breast cancer cells. MTT assay was used to quantify the inhibitory effect of the drugs on breast cancer cells in vitro. SCID mice injected with HCC1428 cells followed by different treatments were used to assess the in vivo efficacy of different agents. Data showed that the combination of everolimus and metformin exerted synergistic inhibitory effects on the growth of breast cancer cells both in culture and in a mouse xenograft model. Further, this combination abrogated S6 and 4EBP1phosphorylation. Collectively, we suggest that the combination of everolimus and metformin may be an effective regimen for treatment of breast cancer, hence warranting further evaluation of the combination in the clinic. PMID:26351208

  17. Pivotal Role of mTOR Signaling in Hepatocellular Carcinoma

    PubMed Central

    Villanueva, Augusto; Chiang, Derek Y.; Newell, Pippa; Peix, Judit; Thung, Swan; Alsinet, Clara; Tovar, Victoria; Roayaie, Sasan; Minguez, Beatriz; Sole, Manel; Battiston, Carlo; van Laarhoven, Stijn; Fiel, Maria I; Di Feo, Analisa; Hoshida, Yujin; Yea, Steven; Toffanin, Sara; Ramos, Alex; Martignetti, John A.; Mazzaferro, Vincenzo; Bruix, Jordi; Waxman, Samuel; Schwartz, Myron; Meyerson, Matthew; Friedman, Scott L.; Llovet, Josep M.

    2008-01-01

    BACKGROUND The advent of targeted therapies in hepatocellular carcinoma (HCC) has underscored the importance of pathway characterization to identify novel molecular targets for treatment. Based on its role in cell growth and differentiation, we evaluated mTOR signaling activation in human HCC, as well as the anti-tumoral effect of a dual-level blockade of the mTOR pathway. METHODS The mTOR pathway was assessed using integrated data from mutation analysis (direct sequencing), DNA copy number changes (SNP-array), mRNA levels (qRT-PCR and gene expression microarray), and protein activation (immunostaining) in 351 human samples, including HCC (n=314), and non-tumoral tissue (n=37). Effects of dual blockade of mTOR signaling using a rapamycin analog (everolimus) and an EGFR/VEGFR inhibitor (AEE788) were evaluated in liver cancer cell lines, and in a tumor xenograft model. RESULTS Aberrant mTOR signaling (phosphorylated-RPS6) was present in half of the cases, associated with IGF pathway activation, EGF upregulation, and PTEN dysregulation. PTEN and PI3KCA-B mutations were rare events. Chromosomal gains in RICTOR (25% of patients) and positive pRPS6 staining correlated with recurrence. RICTOR-specific siRNA downregulation reduced tumor cell viability in vitro. Blockage of mTOR signaling with everolimus in vitro and in a xenograft model decelerated tumor growth and increased survival. This effect was enhanced in vivo after EGFR blockade. CONCLUSIONS MTOR signaling has a critical role in the pathogenesis of HCC, with evidence for the role of RICTOR in tumor oncogenesis. MTOR blockade with everolimus is effective in vivo. These findings establish a rationale for targeting mTOR pathway in clinical trials in HCC. PMID:18929564

  18. Evaluation of the Impact of the Cancer Therapy Everolimus on the Central Nervous System in Mice

    PubMed Central

    Dubois, Martine; Le Joncour, Vadim; Tonon, Marie-Christine; Anouar, Youssef; Proust, François; Morin, Fabrice; Gandolfo, Pierrick; Joly, Florence; Hilber, Pascal; Castel, Hélène

    2014-01-01

    Cancer and treatments may induce cognitive impairments in cancer patients, and the causal link between chemotherapy and cognitive dysfunctions was recently validated in animal models. New cancer targeted therapies have become widely used, and their impact on brain functions and quality of life needs to be explored. We evaluated the impact of everolimus, an anticancer agent targeting the mTOR pathway, on cognitive functions, cerebral metabolism, and hippocampal cell proliferation/vascular density in mice. Adult mice received everolimus daily for 2 weeks, and behavioral tests were performed from 1 week after the last treatment. Everolimus-treated mice displayed a marked reduction in weight gain from the last day of the treatment period. Ex vivo analysis showed altered cytochrome oxidase activity in selective cerebral regions involved in energy balance, food intake, reward, learning and memory modulation, sleep/wake cycle regulation, and arousal. Like chemotherapy, everolimus did not alter emotional reactivity, learning and memory performances, but in contrast to chemotherapy, did not affect behavioral flexibility or reactivity to novelty. In vivo hippocampal neural cell proliferation and vascular density were also unchanged after everolimus treatments. In conclusion, two weeks daily everolimus treatment at the clinical dose did not evoke alteration of cognitive performances evaluated in hippocampal- and prefrontal cortex-dependent tasks that would persist at one to four weeks after the end of the treatment completion. However, acute everolimus treatment caused selective CO modifications without altering the mTOR effector P70S6 kinase in cerebral regions involved in feeding behavior and/or the sleep/wake cycle, at least in part under control of the solitary nucleus and the parasubthalamic region of the hypothalamus. Thus, this area may represent a key target for everolimus-mediating peripheral modifications, which has been previously associated with symptoms such as

  19. Establishment of novel cell lines recapitulating the genetic landscape of uveal melanoma and preclinical validation of mTOR as a therapeutic target.

    PubMed

    Amirouchene-Angelozzi, Nabil; Nemati, Fariba; Gentien, David; Nicolas, André; Dumont, Amaury; Carita, Guillaume; Camonis, Jacques; Desjardins, Laurence; Cassoux, Nathalie; Piperno-Neumann, Sophie; Mariani, Pascale; Sastre, Xavier; Decaudin, Didier; Roman-Roman, Sergio

    2014-12-01

    Uveal melanoma (UM) is the most common primary tumor of the eye in adults. There is no standard adjuvant treatment to prevent metastasis and no effective therapy in the metastatic setting. We have established a unique panel of 7 UM cell lines from either patient's tumors or patient-derived tumor xenografts (PDXs). This panel recapitulates the molecular landscape of the disease in terms of genetic alterations and mutations. All the cell lines display GNAQ or GNA11 activating mutations, and importantly four of them display BAP1 (BRCA1 associated protein-1) deficiency, a hallmark of aggressive disease. The mTOR pathway was shown to be activated in most of the cell lines independent of AKT signaling. mTOR inhibitor Everolimus reduced the viability of UM cell lines and significantly delayed tumor growth in 4 PDXs. Our data suggest that mTOR inhibition with Everolimus, possibly in combination with other agents, may be considered as a therapeutic option for the management of uveal melanoma. PMID:24994677

  20. mTOR Inhibitors in Tuberous Sclerosis Complex.

    PubMed

    Curatolo, Paolo; Moavero, Romina

    2012-12-01

    Tuberous sclerosis complex (TSC) is a genetic multiple organ system disorder that is characterized by the development of tumor-like lesions (hamartomas) and neurodevelopmental disorders. Mutations in the TSC1 and TSC2 tumor suppressor genes occur in the majority of patients with TSC, resulting in hyperactivation of the mammalian target of rapamycin (mTOR) signaling pathway and subsequent abnormalities in numerous cell processes. As a result, mTOR inhibitors such as sirolimus and everolimus have the potential to provide targeted therapy for patients with TSC. Everolimus is the first mTOR inhibitor approved as a treatment option in the USA and in Europe for patients with subependymal giant-cell astrocytomas (SEGAs) associated with TSC. The clinical evidence to date supports the use of mTOR inhibitors in a variety of TSC-associated disease manifestations, including SEGAs, renal angiomyolipoma, skin manifestations, and epilepsy. Furthermore, ongoing clinical trials evaluating mTOR inhibitors in TSC are underway, and the results of these studies are expected to provide further evidence that will firmly establish their role in this setting. This article will discuss the role of the mTOR pathway in TSC and review the pharmacokinetics, pharmacodynamics, clinical efficacy, and tolerability of mTOR inhibitors, along with their current place in clinical practice. PMID:23730262

  1. Combination of everolimus and tacrolimus: a potentially effective regimen for recalcitrant psoriasis.

    PubMed

    Wei, Kai-Che; Lai, Ping-Chin

    2015-01-01

    Severe forms of psoriasis that are refractory to conventional therapies are often difficult to manage. The mammalian target of rapamycin (mTOR) inhibitors potentially have versatile effects toward putative psoriatic pathologic pathways. Therefore, mTOR inhibitors may offer a range of new therapeutic options for patients with psoriasis. We describe a 55-year-old male renal transplant patient with refractory psoriasis. We adjusted his antirejection regimen and put him on everolimus (Certican(®); Novartis, Basel, Switzerland; a semisynthetic macrolide, belonging to the mTOR inhibitors family) with low-dose tacrolimus. This combination regimen maintained his graft function and successfully controlled his psoriasis. His skin lesions never recurred in the next 18 months. To our knowledge, this is the first report showing that the combination of everolimus and tacrolimus could be used to treat recalcitrant psoriasis. The relative benefit-risk profiles of such therapies worth further investigation. PMID:25285355

  2. Physiologically based pharmacokinetic models for everolimus and sorafenib in mice

    PubMed Central

    Pawaskar, Dipti K.; Straubinger, Robert M.; Fetterly, Gerald J.; Hylander, Bonnie H.; Repasky, Elizabeth A.; Ma, Wen W.

    2013-01-01

    Purpose Everolimus is a mammalian target of rapamycin (mTOR) inhibitor approved as an immunosuppressant and for second-line therapy of hepatocellular carcinoma (HCC) and renal cell carcinoma (RCC). Sorafenib is a multikinase inhibitor used as first-line therapy in HCC and RCC. This study assessed the pharmacokinetics (PK) of everolimus and sorafenib alone and in combination in plasma and tissues, developed physiologically based pharmacokinetic (PBPK) models in mice, and assessed the possibility of PK drug interactions. Methods Single and multiple oral doses of everolimus and sorafenib were administered alone and in combination in immunocompetent male mice and to severe combined immune-deficient (SCID) mice bearing low-passage, patient-derived pancreatic adenocarcinoma in seven different studies. Plasma and tissue samples including tumor were collected over a 24-h period and analyzed by liquid chromatography-tandem mass spectrometry (LC–MS/MS). Distribution of everolimus and sorafenib to the brain, muscle, adipose, lungs, kidneys, pancreas, spleen, liver, GI, and tumor was modeled as perfusion rate-limited, and all data from the diverse studies were fitted simultaneously using a population approach. Results PBPK models were developed for everolimus and sorafenib. PBPK analysis showed that the two drugs in combination had the same PK as each drug given alone. A twofold increase in sorafenib dose increased tumor exposure tenfold, thus suggesting involvement of transporters in tumor deposition of sorafenib. Conclusions The developed PBPK models suggested the absence of PK interaction between the two drugs in mice. These studies provide the basis for pharmacodynamic evaluation of these drugs in patient-derived primary pancreatic adenocarcinomas explants. PMID:23455451

  3. Next-generation sequencing reveals somatic mutations that confer exceptional response to everolimus

    PubMed Central

    Kim, Sangwoo; Kim, Sora; Ali, Siraj M.; Greenbowe, Joel R.; Yang, In Seok; Kwon, Nak-Jung; Lee, Jae Lyun; Ryu, Min-Hee; Ahn, Jin-Hee; Lee, Jeeyun; Lee, Min Goo; Kim, Hyo Song; Kim, Hyunki; Kim, Hye Ryun; Moon, Yong Wha; Chung, Hyun Cheol; Kim, Joo-Hang; Kang, Yoon-Koo; Cho, Byoung Chul

    2016-01-01

    Background Given the modest responses to everolimus, a mTOR inhibitor, in multiple tumor types, there is a pressing need to identify predictive biomarkers for this drug. Using targeted ultra-deep sequencing, we aimed to explore genomic alterations that confer extreme sensitivity to everolimus. Results We collected formalin-fixed paraffin-embedded tumor/normal pairs from 39 patients (22 with exceptional clinical benefit, 17 with no clinical benefit) who were treated with everolimus across various tumor types (13 gastric cancers, 15 renal cell carcinomas, 2 thyroid cancers, 2 head and neck cancer, and 7 sarcomas). Ion AmpliSeqTM Comprehensive Cancer Panel was used to identify alterations across all exons of 409 target genes. Tumors were sequenced to a median coverage of 552x. Cancer genomes are characterized by 219 somatic single-nucleotide variants (181 missense, 9 nonsense, 7 splice-site) and 22 frameshift insertions/deletions, with a median of 2.1 mutations per Mb (0 to 12.4 mutations per Mb). Overall, genomic alterations with activating effect on mTOR signaling were identified in 10 of 22 (45%) patients with clinical benefit and these include MTOR, TSC1, TSC2, NF1, PIK3CA and PIK3CG mutations. Recurrently mutated genes in chromatin remodeling genes (BAP1; n = 2, 12%) and receptor tyrosine kinase signaling (FGFR4; n = 2, 12%) were noted only in patients without clinical benefit. Conclusions Regardless of different cancer types, mTOR-pathway-activating mutations confer sensitivity to everolimus. Targeted sequencing of mTOR pathway genes facilitates identification of potential candidates for mTOR inhibitors. PMID:26859683

  4. Everolimus in the treatment of patients with advanced pancreatic neuroendocrine tumors: latest findings and interpretations

    PubMed Central

    Liu, Eric; Marincola, Paula

    2013-01-01

    Pancreatic neuroendocrine tumors (pNETs) are a heterogeneous group of neoplasms with various clinical presentations. More than half of patients present with so-called nonfunctioning tumors with no hormone-related symptoms, whereas other tumors produce symptoms like gastric problems, ulcers, hypoglycemia, skin rash and diarrhea related to hormone production. The traditional treatment for pNETs over the last three decades has been cytotoxic agents, mainly streptozotocin plus 5-fluorouracil or doxorubicin. Most recently two new compounds have been registered worldwide for the treatment of pNETs, the mammalian target of rapamycin (mTOR) inhibitor everolimus and the tyrosine kinase inhibitor sunitinib. This paper concentrates on the use of mTOR inhibitors and the mechanisms of action. The mTOR pathway is altered in a number of pNETs. Everolimus (RAD001) is an orally active rapamycin analog and mTOR inhibitor. It blocks activity of the mTOR pathway by binding with high affinity to the cytoplasmic protein FKBP-12. The efficacy of everolimus in pNETs has been demonstrated in two multicenter studies (RADIANT 1 and 3). The RADIANT 3 study was a randomized controlled study in pNETs of everolimus 10 mg/day versus placebo, showing an increased progression-free survival (11.7 months versus 4.6 months) and hazard ratio of 0.35 (p < 0.001). Current studies indicate that there is strong evidence to support the antitumor effect of rapalogs in pNETs. However, significant tumor reduction is very rarely obtained, usually in less than 10% of treated patients. Therefore, these drugs may be more effective in combination with other anticancer agents, including chemotherapy, targeted therapies as well as peptide receptor radiotherapy. PMID:24003341

  5. Everolimus in the management of metastatic renal cell carcinoma: an evidence-based review of its place in therapy

    PubMed Central

    Buti, Sebastiano; Leonetti, Alessandro; Dallatomasina, Alice; Bersanelli, Melissa

    2016-01-01

    Introduction Renal cell carcinoma (RCC) is the most common type of kidney cancer in adults, and its pathogenesis is strictly related to altered cellular response to hypoxia, in which mTOR signaling pathway is implicated. Everolimus, an mTOR serine/threonine kinase inhibitor, represents a therapeutic option for the treatment of advanced RCC. Aim The objective of this article is to review the evidence for the treatment of metastatic RCC with everolimus. Evidence review Everolimus was approved for second- and third-line therapy in patients with advanced RCC according to the results of a Phase III pivotal trial that demonstrated a benefit in median progression-free survival of ~2 months compared to placebo after failure of previous lines of therapy, of which at least one was an anti-VEGFR tyrosine kinase inhibitor (TKI). The role of this drug in first-line setting has been investigated in Phase II trials, with no significant clinical benefit, even in combination with bevacizumab. Everolimus activity in non-clear cell RCC is supported by two randomized Phase II trials that confirmed the benefit in second-line setting but not in first line. Recently, two randomized Phase III trials (METEOR and CheckMate 025) demonstrated the inferiority of everolimus in second-line setting compared to the TKI cabozantinib and to the immune checkpoint inhibitor nivolumab, respectively. Moreover, a recent Phase II study demonstrated a significant benefit for the second-line combination treatment with everolimus plus lenvatinib (a novel TKI) in terms of progression-free survival and overall survival compared to the single-agent everolimus. Basing on preclinical data, the main downstream effectors of mTOR cascade, S6RP and its phosphorylated form, could be good predictive biomarkers of response to everolimus. The safety profile of the drug is favorable, with a good cost-effectiveness compared to second-line sorafenib or axitinib, and no significant impact on the quality of life of treated

  6. Treatment of relapsed/refractory chronic lymphocytic leukemia/small lymphocytic lymphoma with everolimus (RAD001) and alemtuzumab: a Phase I/II study.

    PubMed

    Zent, Clive S; Bowen, Deborah A; Conte, Michael J; LaPlant, Betsy R; Call, Timothy G

    2016-07-01

    Patients with relapsed/refractory chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL), and especially those with purine analogue refractory disease or TP53 deletion/mutation, had a poor prognosis prior to the introduction of therapy targeting B cell receptor signaling. The mammalian target of rapamycin (mTOR) inhibitor everolimus has biological activity in CLL and can mobilize CLL cells from the lymphoid tissues into the circulation. In this clinical trial we determined the maximum tolerated dose (MTD) of everolimus together with eight weeks of standard dose subcutaneous alemtuzumab (Phase I) and then evaluated the tolerability and efficacy of therapy of relapsed/refractory CLL with the combination of everolimus and alemtuzumab (Phase II). The maximum tolerated dose of oral everolimus was 2.5 mg three times/week. Therapy with everolimus and alemtuzumab was tolerable, but not sufficiently efficacious (33% partial responses, no complete responses) to recommend further development of the regimen. PMID:26699397

  7. Everolimus improves neuropsychiatric symptoms in a patient with tuberous sclerosis carrying a novel TSC2 mutation.

    PubMed

    Hwang, Su-Kyeong; Lee, Jae-Hyung; Yang, Jung-Eun; Lim, Chae-Seok; Lee, Jin-A; Lee, Yong-Seok; Lee, Kyungmin; Kaang, Bong-Kiun

    2016-01-01

    Tuberous sclerosis complex (TSC) is a neurocutaneous disorder characterized by multiple symptoms including neuropsychological deficits such as seizures, intellectual disability, and autism. TSC is inherited in an autosomal dominant pattern and is caused by mutations in either the TSC1 or TSC2 genes, which enhance activation of the mammalian target of rapamycin (mTOR) signaling pathway. Recent studies have suggested that mTOR inhibitors such as rapamycin can reverse TSC-associated deficits in rodent models of TSC. In addition, clinical trials are ongoing to test the efficacy of mTOR inhibitors toward the psychiatric symptoms associated with TSC. Here, we report a case study of a Korean patient with TSC, who exhibited multiple symptoms including frequent seizures, intellectual disability, language delays, and social problems. We performed whole exome sequencing and identified a novel small deletion mutation in TSC2. Expressing the novel deletion mutant in HEK293T cells significantly increased mTOR pathway activation. Furthermore, everolimus treatment showed not only reduction in SEGA size, but dramatically improved behavioral deficits including autism related behaviors in the patient. In summary, we identified a novel small deletion mutation in TSC2 associated with severe TSC in a Korean family that enhances the activation of mTOR signaling in vitro. Everolimus treatment improved behavioral deficits in the patient. PMID:27216612

  8. [Management of metabolic disorders induced by everolimus in patients with differentiated neuroendocrine tumors: expert proposals].

    PubMed

    Lombard-Bohas, Catherine; Cariou, Bertrand; Vergès, Bruno; Coriat, Romain; N'guyen, Thierry; François, Eric; Hammel, Pascal; Niccoli, Patricia; Hentic, Olivia

    2014-02-01

    Medical management of pancreatic neuroendocrine tumors has recently been improved by new molecules of which the mTOR inhibitor everolimus. If digestive neuroendocrine tumors are rare, the incidence is in constant increase and the prevalence in digestive cancers put them right behind colorectal cancers. Everolimus has demonstrated efficacy in unresectable and progressive pancreatic neuroendocrine tumors, by doubling the median progression free survival (11 versus 4.6 months), with a median time of exposure to everolimus of nine months. Everolimus is generally maintained until progression or intolerance and some patients are treated during several years. Potential metabolic disorders induced by everolimus (dyslipidemia, hyperglycemia) in patients with life expectancy of several years, justify monitoring of these parameters and accurate treatment management algorithm. These will avoid worsening patient's prognostic, but also prematurely discontinue potentially effective treatment or contraindicate other therapeutic weapons, in a pathology in which there are multiple therapeutic options in metastatic phase. We propose a standard practice in terms of initial assessment, monitoring, care threshold, and therapeutic objectives to manage metabolic disorders, fitted to our patients with advanced pancreatic neuroendocrine tumors. PMID:24557872

  9. Prevention of BMS-777607-induced polyploidy/senescence by mTOR inhibitor AZD8055 sensitizes breast cancer cells to cytotoxic chemotherapeutics.

    PubMed

    Sharma, Sharad; Yao, Hang-Ping; Zhou, Yong-Qing; Zhou, Jianwei; Zhang, Ruiwen; Wang, Ming-Hai

    2014-05-01

    Targeted inhibition of MET/RON signaling by tyrosine kinase inhibitor BMS-777607 for cancer treatment is currently under clinical trials. We have previously shown that BMS-777607 induces chemoresistance in vitro by causing polyploidy, which hampers therapeutic efficacy. Here, we studied polyploidy-associated senescence induced by BMS-777607 in breast cancer cells and its prevention by mTOR inhibitor AZD8055, leading to increased chemosensitivity. In breast cancer T-47D and ZR-75-1 cells, BMS-777607 induced phenotypic changes including enlarged cellular size, flattened morphology, increased DNA content, and activity of senescence-associated β-galactosidase. These changes were accompanied by increased p21/WAF1 expression and decreased Retinoblastoma Ser(780) phosphorylation, indicating that BMS-777607 induces not only polyploidy but also senescence. The appearance of senescence was associated with polyploidy in which β-galactosidase is exclusively expressed in polyploid cells. Survivin expression was increased in polyploid/senescent cells as analyzed by Western blotting. Increased survivin accumulated both in the nucleus and cytoplasm and dissociated with condensed DNA and mitotic spindle at the metaphase. Abnormal accumulation of survivin also rendered polyploid/senescent cells insensitive to cytotoxic activities of YM155, a DNA damaging agent with a suppressive effect on survivin gene transcription. AZD8055, a specific mTOR inhibitor, effectively prevented BMS-777607-induced polyploidy and senescence and restored survivin expression and its nuclear localization to normal levels. Although a synergism was not observed, BMS-777607 plus AZD8055 increased cancer cell sensitivity toward different cytotoxic chemotherapeutics. In conclusion, BMS-777607-induced chemoresistance is associated with cell polyploidy and senescence. Inhibition of mTOR signaling by AZD8055 prevents BMS-777607-induced polyploidy/senescence and increases breast cancer cell chemosensitivity. PMID

  10. Lipopolysaccharide Exposure Induces Maternal Hypozincemia, and Prenatal Zinc Treatment Prevents Autistic-Like Behaviors and Disturbances in the Striatal Dopaminergic and mTOR Systems of Offspring.

    PubMed

    Kirsten, Thiago Berti; Chaves-Kirsten, Gabriela P; Bernardes, Suene; Scavone, Cristoforo; Sarkis, Jorge E; Bernardi, Maria Martha; Felicio, Luciano F

    2015-01-01

    Autism is characterized by social deficits, repetitive behaviors, and cognitive inflexibility. The risk factors appear to include genetic and environmental conditions, such as prenatal infections and maternal dietary factors. Previous investigations by our group have demonstrated that prenatal exposure to lipopolysaccharide (LPS), which mimics infection by gram-negative bacteria, induces autistic-like behaviors. To understand the causes of autistic-like behaviors, we evaluated maternal serum metal concentrations, which are involved in intrauterine development and infection/inflammation. We identified reduced maternal levels of zinc, magnesium, selenium and manganese after LPS exposure. Because LPS induced maternal hypozincemia, we treated dams with zinc in an attempt to prevent or ease the impairments in the offspring. We evaluated the social and cognitive autistic-like behaviors and brain tissues of the offspring to identify the central mechanism that triggers the development of autism. Prenatal LPS exposure impaired play behaviors and T-maze spontaneous alternations, i.e., it induced autistic-like behaviors. Prenatal LPS also decreased tyrosine hydroxylase levels and increased the levels of mammalian target of rapamycin (mTOR) in the striatum. Thus, striatal dopaminergic impairments may be related to autism. Moreover, excessive signaling through the mTOR pathway has been considered a biomarker of autism, corroborating our rat model of autism. Prenatal zinc treatment prevented these autistic-like behaviors and striatal dopaminergic and mTOR disturbances in the offspring induced by LPS exposure. The present findings revealed a possible relation between maternal hypozincemia during gestation and the onset of autism. Furthermore, prenatal zinc administration appears to have a beneficial effect on the prevention of autism. PMID:26218250

  11. Lipopolysaccharide Exposure Induces Maternal Hypozincemia, and Prenatal Zinc Treatment Prevents Autistic-Like Behaviors and Disturbances in the Striatal Dopaminergic and mTOR Systems of Offspring

    PubMed Central

    Kirsten, Thiago Berti; Chaves-Kirsten, Gabriela P.; Bernardes, Suene; Scavone, Cristoforo; Sarkis, Jorge E.; Bernardi, Maria Martha; Felicio, Luciano F.

    2015-01-01

    Autism is characterized by social deficits, repetitive behaviors, and cognitive inflexibility. The risk factors appear to include genetic and environmental conditions, such as prenatal infections and maternal dietary factors. Previous investigations by our group have demonstrated that prenatal exposure to lipopolysaccharide (LPS), which mimics infection by gram-negative bacteria, induces autistic-like behaviors. To understand the causes of autistic-like behaviors, we evaluated maternal serum metal concentrations, which are involved in intrauterine development and infection/inflammation. We identified reduced maternal levels of zinc, magnesium, selenium and manganese after LPS exposure. Because LPS induced maternal hypozincemia, we treated dams with zinc in an attempt to prevent or ease the impairments in the offspring. We evaluated the social and cognitive autistic-like behaviors and brain tissues of the offspring to identify the central mechanism that triggers the development of autism. Prenatal LPS exposure impaired play behaviors and T-maze spontaneous alternations, i.e., it induced autistic-like behaviors. Prenatal LPS also decreased tyrosine hydroxylase levels and increased the levels of mammalian target of rapamycin (mTOR) in the striatum. Thus, striatal dopaminergic impairments may be related to autism. Moreover, excessive signaling through the mTOR pathway has been considered a biomarker of autism, corroborating our rat model of autism. Prenatal zinc treatment prevented these autistic-like behaviors and striatal dopaminergic and mTOR disturbances in the offspring induced by LPS exposure. The present findings revealed a possible relation between maternal hypozincemia during gestation and the onset of autism. Furthermore, prenatal zinc administration appears to have a beneficial effect on the prevention of autism. PMID:26218250

  12. The mTOR Signalling Pathway in Human Cancer

    PubMed Central

    Pópulo, Helena; Lopes, José Manuel; Soares, Paula

    2012-01-01

    The conserved serine/threonine kinase mTOR (the mammalian target of rapamycin), a downstream effector of the PI3K/AKT pathway, forms two distinct multiprotein complexes: mTORC1 and mTORC2. mTORC1 is sensitive to rapamycin, activates S6K1 and 4EBP1, which are involved in mRNA translation. It is activated by diverse stimuli, such as growth factors, nutrients, energy and stress signals, and essential signalling pathways, such as PI3K, MAPK and AMPK, in order to control cell growth, proliferation and survival. mTORC2 is considered resistant to rapamycin and is generally insensitive to nutrients and energy signals. It activates PKC-α and AKT and regulates the actin cytoskeleton. Deregulation of multiple elements of the mTOR pathway (PI3K amplification/mutation, PTEN loss of function, AKT overexpression, and S6K1, 4EBP1 and eIF4E overexpression) has been reported in many types of cancers, particularly in melanoma, where alterations in major components of the mTOR pathway were reported to have significant effects on tumour progression. Therefore, mTOR is an appealing therapeutic target and mTOR inhibitors, including the rapamycin analogues deforolimus, everolimus and temsirolimus, are submitted to clinical trials for treating multiple cancers, alone or in combination with inhibitors of other pathways. Importantly, temsirolimus and everolimus were recently approved by the FDA for the treatment of renal cell carcinoma, PNET and giant cell astrocytoma. Small molecules that inhibit mTOR kinase activity and dual PI3K-mTOR inhibitors are also being developed. In this review, we aim to survey relevant research, the molecular mechanisms of signalling, including upstream activation and downstream effectors, and the role of mTOR in cancer, mainly in melanoma. PMID:22408430

  13. Prevention of tumor growth driven by PIK3CA and HPV oncogenes by targeting mTOR signaling with metformin in oral squamous carcinomas expressing OCT3

    PubMed Central

    Madera, Dmitri; Vitale-Cross, Lynn; Martin, Daniel; Schneider, Abraham; Molinolo, Alfredo A.; Gangane, Nitin; Carey, Thomas E.; McHugh, Jonathan B.; Komarck, Christine M.; Walline, Heather M.; William, William N.; Seethala, Raja R.; Ferris, Robert; Gutkind, J. Silvio

    2015-01-01

    Most head and neck squamous cell carcinomas (HNSCC) exhibit a persistent activation of the PI3K-mTOR signaling pathway. We have recently shown that metformin, an oral antidiabetic drug that is also used to treat lipodystrophy in HIV-infected (HIV+) individuals, diminishes mTOR activity and prevents the progression of chemically-induced experimental HNSCC premalignant lesions. Here, we explored the preclinical activity of metformin in HNSCCs harboring PIK3CA mutations and HPV oncogenes, both representing frequent HNSCC alterations, aimed at developing effective targeted preventive strategies. The biochemical and biological effects of metformin were evaluated in representative HNSCC cells expressing mutated PIK3CA or HPV oncogenes (HPV+). The oral delivery of metformin was optimized to achieve clinical relevant blood levels. Molecular determinants of metformin sensitivity were also investigated, and their expression levels examined in a large collection of HNSCC cases. We found that metformin inhibits mTOR signaling and tumor growth in HNSCC cells expressing mutated PIK3CA and HPV oncogenes, and that these activities require the expression of organic cation transporter 3 (OCT3/SLC22A3), a metformin uptake transporter. Co-expression of OCT3 and the mTOR pathway activation marker pS6 were observed in most HNSCC cases, including those arising in HIV+ patients. Activation of the PI3K-mTOR pathway is a widespread event in HNSCC, including HPV− and HPV+ lesions arising in HIV+ patients, all of which co-express OCT3. These observations may provide a rationale for the clinical evaluation of metformin to halt HNSCC development from precancerous lesions, including in HIV+ individuals at risk of developing HPV-associated cancers. PMID:25681087

  14. Prevention of tumor growth driven by PIK3CA and HPV oncogenes by targeting mTOR signaling with metformin in oral squamous carcinomas expressing OCT3.

    PubMed

    Madera, Dmitri; Vitale-Cross, Lynn; Martin, Daniel; Schneider, Abraham; Molinolo, Alfredo A; Gangane, Nitin; Carey, Thomas E; McHugh, Jonathan B; Komarck, Christine M; Walline, Heather M; William, William N; Seethala, Raja R; Ferris, Robert L; Gutkind, J Silvio

    2015-03-01

    Most squamous cell carcinomas of the head and neck (HNSCC) exhibit a persistent activation of the PI3K-mTOR signaling pathway. We have recently shown that metformin, an oral antidiabetic drug that is also used to treat lipodystrophy in HIV-infected (HIV(+)) individuals, diminishes mTOR activity and prevents the progression of chemically induced experimental HNSCC premalignant lesions. Here, we explored the preclinical activity of metformin in HNSCCs harboring PIK3CA mutations and HPV oncogenes, both representing frequent HNSCC alterations, aimed at developing effective targeted preventive strategies. The biochemical and biologic effects of metformin were evaluated in representative HNSCC cells expressing mutated PIK3CA or HPV oncogenes (HPV(+)). The oral delivery of metformin was optimized to achieve clinical relevant blood levels. Molecular determinants of metformin sensitivity were also investigated, and their expression levels were examined in a large collection of HNSCC cases. We found that metformin inhibits mTOR signaling and tumor growth in HNSCC cells expressing mutated PIK3CA and HPV oncogenes, and that these activities require the expression of organic cation transporter 3 (OCT3/SLC22A3), a metformin uptake transporter. Coexpression of OCT3 and the mTOR pathway activation marker pS6 were observed in most HNSCC cases, including those arising in HIV(+) patients. Activation of the PI3K-mTOR pathway is a widespread event in HNSCC, including HPV(-) and HPV(+) lesions arising in HIV(+) patients, all of which coexpress OCT3. These observations may provide a rationale for the clinical evaluation of metformin to halt HNSCC development from precancerous lesions, including in HIV(+) individuals at risk of developing HPV(-) associated cancers. PMID:25681087

  15. Everolimus in renal cell carcinoma.

    PubMed

    Wang, Y

    2010-08-01

    Everolimus (also known as RAD-001; Afinitor®) is an orally active inhibitor of the intracellular protein kinase mammalian target of rapamycin. The U.S. Food and Drug Administration and the European Medicines Agency recently approved everolimus for the treatment of advanced renal cell carcinoma (RCC) on the basis of the results of a randomized phase III clinical trial. In the trial, 10 mg daily everolimus was effective and well tolerated by patients with advanced RCC, whose disease had progressed while under the treatment with sunitinib and/or sorafenib. Everolimus treatment led to 36% of 6-month progression-free survival (PFS) rate and 31% of 3-month PFS rate. Most of the adverse events were mild to moderate (grade 1-2) in severity. The most frequent grade 3-4 adverse events were stomatitis, fatigue, pneumonitis and infections. Clinical trials on everolimus in combination with sunitinib, sorafenib, imatinib and vatalanib for the treatment of RCC are ongoing. PMID:20830316

  16. The dual targeting of insulin and insulin-like growth factor 1 receptor enhances the mTOR inhibitor-mediated antitumor efficacy in hepatocellular carcinoma

    PubMed Central

    Pivonello, Claudia; Negri, Mariarosaria; De Martino, Maria Cristina; Napolitano, Maria; de Angelis, Cristina; Provvisiero, Donatella Paola; Cuomo, Gaia; Auriemma, Renata Simona; Simeoli, Chiara; Izzo, Francesco; Colao, Annamaria; Hofland, Leo J.; Pivonello, Rosario

    2016-01-01

    Deregulation of mTOR and IGF pathways is frequent in hepatocellular carcinoma (HCC), thus mTOR and IGF1R represent suitable therapeutic targets in HCC. The aim of this study was to evaluate the effects of mTOR inhibitors (mTORi) and OSI-906, blocker of IGF1R/IR, on HCC cell proliferation, viability, migration and invasion, and alpha-fetoprotein (α-FP) secretion. In HepG2 and HuH-7 we evaluated, the expression of mTOR and IGF pathway components; the effects of Sirolimus, Everolimus, Temsirolimus and OSI-906 on cell proliferation; the effects of Sirolimus, OSI-906, and their combination, on cell secretion, proliferation, viability, cell cycle, apoptosis, invasion and migration. Moreover, intracellular mechanisms underlying these cell functions were evaluated in both cell lines. Our results show that HepG2 and HuH-7 present with the same mRNA expression profile with high levels of IGF2. OSI-906 inhibited cell proliferation at high concentration, while mTORi suppressed cell proliferation in a dose-time dependent manner in both cell lines. The co-treatment showed an additive inhibitory effect on cell proliferation and viability. This effect was not related to induction of apoptosis, but to G0/G1 phase block. Moreover, the co-treatment prevented the Sirolimus-induced AKT activation as escape mechanism. Both agents demonstrated to be differently effective in inhibiting α-FP secretion. Sirolimus, OSI-906, and their combination, blocked cell migration and invasion in HuH-7. These findings indicate that, co-targeting of IGF1R/IR and mTOR pathways could be a novel therapeutic approach in the management of HCC, in order to maximize antitumoral effect and to prevent the early development of resistance mechanisms. PMID:26756219

  17. The dual targeting of insulin and insulin-like growth factor 1 receptor enhances the mTOR inhibitor-mediated antitumor efficacy in hepatocellular carcinoma.

    PubMed

    Pivonello, Claudia; Negri, Mariarosaria; De Martino, Maria Cristina; Napolitano, Maria; de Angelis, Cristina; Provvisiero, Donatella Paola; Cuomo, Gaia; Auriemma, Renata Simona; Simeoli, Chiara; Izzo, Francesco; Colao, Annamaria; Hofland, Leo J; Pivonello, Rosario

    2016-03-01

    Deregulation of mTOR and IGF pathways is frequent in hepatocellular carcinoma (HCC), thus mTOR and IGF1R represent suitable therapeutic targets in HCC. The aim of this study was to evaluate the effects of mTOR inhibitors (mTORi) and OSI-906, blocker of IGF1R/IR, on HCC cell proliferation, viability, migration and invasion, and alpha-fetoprotein (α-FP) secretion. In HepG2 and HuH-7 we evaluated, the expression of mTOR and IGF pathway components; the effects of Sirolimus, Everolimus, Temsirolimus and OSI-906 on cell proliferation; the effects of Sirolimus, OSI-906, and their combination, on cell secretion, proliferation, viability, cell cycle, apoptosis, invasion and migration. Moreover, intracellular mechanisms underlying these cell functions were evaluated in both cell lines. Our results show that HepG2 and HuH-7 present with the same mRNA expression profile with high levels of IGF2. OSI-906 inhibited cell proliferation at high concentration, while mTORi suppressed cell proliferation in a dose-time dependent manner in both cell lines. The co-treatment showed an additive inhibitory effect on cell proliferation and viability. This effect was not related to induction of apoptosis, but to G0/G1 phase block. Moreover, the co-treatment prevented the Sirolimus-induced AKT activation as escape mechanism. Both agents demonstrated to be differently effective in inhibiting α-FP secretion. Sirolimus, OSI-906, and their combination, blocked cell migration and invasion in HuH-7. These findings indicate that, co-targeting of IGF1R/IR and mTOR pathways could be a novel therapeutic approach in the management of HCC, in order to maximize antitumoral effect and to prevent the early development of resistance mechanisms. PMID:26756219

  18. Interaction of sirolimus and everolimus with hepatic and intestinal organic anion-transporting polypeptide transporters.

    PubMed

    Picard, Nicolas; Levoir, Laure; Lamoureux, Fabien; Yee, Sook Wah; Giacomini, Kathleen M; Marquet, Pierre

    2011-09-01

    The goal of this study was to assess the interaction of the mTOR inhibitors (ImTORs) sirolimus and everolimus with the human organic anion-transporting polypeptides (OATPs) expressed in hepatocytes and enterocytes by conducting uptake experiments using (i) transfected HEK293T cells, (ii) the hepatocyte-like HepaRG cell line and (iii) the enterocyte-like Caco-2 cell line. Sirolimus and everolimus inhibited in a dose-dependent manner the uptake of [³H]-estrone sulphate by OATP1A2 and OATP1B1 and that of mycophenolic acid 7-O-glucuronide (MPAG) by OATP1B3. ImTOR apparent 50% inhibitory concentrations (IC₅₀) for OATPs were 11.9 µM (OATP1A2), 9.8 µM (OATP1B1) and 1.3 µM (OATP1B3) for sirolimus and 4.2 µM (OATP1A2), 4.1 µM (OATP1B1) and 4.3 µM (OATP1B3) for everolimus. No transport of sirolimus or everolimus by OATP1A2, OATP1B1 or OATP1B3 was observed in HEK-transfected cells and the OAT/OATP/MRP chemical inhibitor probenecid did not significantly decrease the uptake of sirolimus and everolimus in HepaRG and Caco-2 cells, but tended to increase their intracellular accumulation presumably through efflux inhibition. In conclusion, our data suggest that the major OATP transporters expressed in the liver and the intestine do not contribute to the pharmacokinetics of sirolimus and everolimus. However, ImTORs are inhibitors of these transporters. PMID:21524191

  19. Role of mTOR Inhibitors in Kidney Disease

    PubMed Central

    Kajiwara, Moto; Masuda, Satohiro

    2016-01-01

    The first compound that inhibited the mammalian target of rapamycin (mTOR), sirolimus (rapamycin) was discovered in the 1970s as a soil bacterium metabolite collected on Easter Island (Rapa Nui). Because sirolimus showed antiproliferative activity, researchers investigated its molecular target and identified the TOR1 and TOR2. The mTOR consists of mTOR complex 1 (mTORC1) and mTORC2. Rapalogues including sirolimus, everolimus, and temsirolimus exert their effect mainly on mTORC1, whereas their inhibitory effect on mTORC2 is mild. To obtain compounds with more potent antiproliferative effects, ATP-competitive inhibitors of mTOR targeting both mTORC1 and mTORC2 have been developed and tested in clinical trials as anticancer drugs. Currently, mTOR inhibitors are used as anticancer drugs against several solid tumors, and immunosuppressive agents for transplantation of various organs. This review discusses the role of mTOR inhibitors in renal disease with a particular focus on renal cancer, diabetic nephropathy, and kidney transplantation. PMID:27338360

  20. Role of mTOR Inhibitors in Kidney Disease.

    PubMed

    Kajiwara, Moto; Masuda, Satohiro

    2016-01-01

    The first compound that inhibited the mammalian target of rapamycin (mTOR), sirolimus (rapamycin) was discovered in the 1970s as a soil bacterium metabolite collected on Easter Island (Rapa Nui). Because sirolimus showed antiproliferative activity, researchers investigated its molecular target and identified the TOR1 and TOR2. The mTOR consists of mTOR complex 1 (mTORC1) and mTORC2. Rapalogues including sirolimus, everolimus, and temsirolimus exert their effect mainly on mTORC1, whereas their inhibitory effect on mTORC2 is mild. To obtain compounds with more potent antiproliferative effects, ATP-competitive inhibitors of mTOR targeting both mTORC1 and mTORC2 have been developed and tested in clinical trials as anticancer drugs. Currently, mTOR inhibitors are used as anticancer drugs against several solid tumors, and immunosuppressive agents for transplantation of various organs. This review discusses the role of mTOR inhibitors in renal disease with a particular focus on renal cancer, diabetic nephropathy, and kidney transplantation. PMID:27338360

  1. mTOR inhibition as a Therapeutic Strategy in the Management of Urologic Malignancies

    PubMed Central

    Garcia, Jorge A.; Danielpour, David

    2008-01-01

    The mammalian target of rapamycin (mTOR) is a protein kinase that regulates protein translation, cell growth and apoptosis. Recently, there has been an enormous increase in our understanding on molecular mechanisms underlying the therapeutics of rapamycin in cancer. Alterations in the pathway regulating mTOR occur in many solid malignancies including prostate, bladder and kidney cancer; and in-vitro and in-vivo models of prostate and bladder cancer have established the importance of the mTOR pathway in control of cancer progression and metastasis. Temsirolimus (Torisel™) and everolimus (RAD-001), two ester analogues of rapamycin, as well as rapamycin itself have clear antitumor activity in in-vitro and in-vivo models, and are under clinical trial investigations for prostate and bladder cancer. Phase II and III trials have already established the clinical efficacy of temsirolimus in renal cancer, and current renal trials are evaluating the combined effects of VEGF and mTOR inhibition. Ongoing studies in prostate and bladder cancer will soon define the activity and safety profiles of everolimus and temsirolimus. Recent molecular advances have uncovered a startling complexity in the macromolecular function of mTOR complexes, with the identification of new mTOR partners (raptor, rictor, FKBP38, PRAS40 and mSIN1), putative cancer therapeutic/prognostic targets for future clinical trials. PMID:18566209

  2. Effects of vatalanib on tumor growth can be potentiated by mTOR blockade in vivo.

    PubMed

    Jaeger-Lansky, Agnes; Cejka, Daniel; Ying, Liu; Preusser, Matthias; Hoeflmayer, Doris; Fuereder, Thorsten; Koehrer, Stefan; Wacheck, Volker

    2010-06-01

    The vascular endothelial growth factor (VEGF) is a central mediator of tumor-induced angiogenesis. Everolimus, a mammalian target of rapamycin (mTOR) inhibitor, decreases VEGF-secretion of cancer cells. Vatalanib is a selective inhibitor of VEGF receptors 1-3. In the present study it was hypothesized that dual inhibition of VEGF signaling by inhibition of VEGF production and VEGF receptor signaling leads to synergistic anti-tumor effects. In vitro, effects of vatalanib and everolimus on cell proliferation, cell cycle, apoptosis and signal transduction were examined in three gastric cancer cell lines. Effects on angiogenesis were assessed using tube formation assays of cultured human umbilical vein endothelial cells (HUVECs). In vivo, the antitumor effect of compounds was studied using a gastric cancer xenograft nude mouse model. VEGF of murine origin (mVEGF) and human cancer cell-derived VEGF (hVEGF) were studied separately by specific ELISAs. Tumor vascularization and proliferation were quantified by immunohistochemistry. In vitro, everolimus but not vatalanib decreased gastric cancer proliferation without inducing apoptosis. Vatalanib abolished endothelial cell tube formation, whereas inhibition of tube formation by everolimus was incomplete. In vivo, the combination of vatalanib with everolimus was superior to single agent treatments and reduced tumor size by about 50% relative to everolimus monotherapy (p < 0.005). Pharmacodynamic analysis of VEGF plasma level showed a decrease of hVEGF by everolimus and indicated a trend towards lower mVEGF level only in the combination group. In line, there was a tendency for lower vascular density and proliferation for combination treatment. We conclude that in a preclinical model of gastric cancer the antitumor activity of vatalanib can be augmented by everolimus. PMID:20404549

  3. A randomized, controlled trial of everolimus-based dual immunosuppression versus standard of care in de novo kidney transplant recipients.

    PubMed

    Chadban, Steven J; Eris, Josette Marie; Kanellis, John; Pilmore, Helen; Lee, Po Chang; Lim, Soo Kun; Woodcock, Chad; Kurstjens, Nicol; Russ, Graeme

    2014-03-01

    Kidney transplant recipients receiving calcineurin inhibitor-based immunosuppression incur increased long-term risks of cancer and kidney fibrosis. Switch to mammalian target of rapamycin (mTOR) inhibitors may reduce these risks. Steroid or Cyclosporin Removal After Transplant using Everolimus (SOCRATES), a 36-month, prospective, multinational, open-label, randomized controlled trial for de novo kidney transplant recipients, assessed whether everolimus switch could enable elimination of mycophenolate plus either steroids or CNI without compromising efficacy. Patients received cyclosporin, mycophenolate and steroids for the first 14 days then everolimus with mycophenolate and CNIwithdrawal (CNI-WD); everolimus with mycophenolate and steroid withdrawal (steroid-WD); or cyclosporin, mycophenolate and steroids (control). 126 patients were randomized. The steroid WD arm was terminated prematurely because of excess discontinuations. Mean eGFR at month 12 for CNI-WD versus control was 65.1 ml/min/1.73 m2 vs. 67.1 ml/min/1.73 m2 by ITT, which met predefined noninferiority criteria (P=0.026). The CNI-WD group experienced a higher rate of BPAR(31% vs. control 13%, P=0.048) and showed a trend towards higher composite treatment failure (BPAR, graft loss, death, loss to follow-up). The 12 month results from SOCRATES show noninferiority in eGFR, but a significant excess of acute rejection when everolimus was commenced at week 2 to enable a progressive withdrawal of mycophenolate and cyclosporin in kidney transplant recipients. PMID:24279685

  4. Functional and histological improvement after everolimus rescue of chronic allograft dysfunction in renal transplant recipients

    PubMed Central

    Chow, Kai Ming; Szeto, Cheuk Chun; Lai, Fernand Mac-Moune; Luk, Cathy Choi-Wan; Kwan, Bonnie Ching-Ha; Leung, Chi Bon; Li, Philip Kam-Tao

    2015-01-01

    Background We tested the strategy of mTOR inhibitors with calcineurin inhibitor minimization in renal transplant recipients with known chronic allograft dysfunction. Methods In this open-label, single-arm study, renal transplant patients were recruited after biopsy-confirmed chronic allograft dysfunction in the absence of acute rejection episode within 2 months, with proteinuria <0.8 g/day, and serum creatinine <220 μmol/L or estimated glomerular filtration rate >40 mL/min/1.73 m2. They were converted to everolimus (aiming for trough everolimus level 3–8 ng/mL) with cyclosporine minimization, to assess the effect on renal function, rate of glomerular filtration rate decline, and longitudinal transplant biopsy at 12 months. Results Seventeen Chinese patients (median transplant duration, 4.2 years) were recruited; no patients discontinued study medication. The mean slope of the glomerular filtration rate over time was −4.31±6.65 mL/min/1.73 m2 per year in the year before everolimus, as compared with 1.29±5.84 mL/min/1.73 m2 per year in the 12 months of everolimus therapy, a difference of 5.61 mL/min/1.73 m2 per year (95% confidence interval [CI], 0.40–10.8) favoring everolimus therapy (P=0.036). Serial renal biopsy histology showed significant decrease of tubular atrophy (15.7%±11.3% versus 7.1%±7.3%, P=0.005) and interstitial fibrosis (14.8%±11.5% versus 7.2%±8.2%, P=0.013). Intrarenal expression of TGF-β1 mRNA showed a nonsignificant decrease after everolimus treatment. Conclusion In renal transplant recipients with biopsy-confirmed chronic allograft dysfunction, we found a significant beneficial effect of everolimus rescue therapy and calcineurin inhibitor minimization strategy on the improvement of glomerular filtration rate decline rate. In secondary analysis, everolimus was shown to slow down the disease progression by reducing the tubular atrophy and interstitial fibrosis scoring. PMID:26056462

  5. Therapeutic potential and adverse events of everolimus for treatment of hepatocellular carcinoma - systematic review and meta-analysis.

    PubMed

    Yamanaka, Kenya; Petrulionis, Marius; Lin, Shibo; Gao, Chao; Galli, Uwe; Richter, Susanne; Winkler, Susanne; Houben, Philipp; Schultze, Daniel; Hatano, Etsuro; Schemmer, Peter

    2013-12-01

    Everolimus is an orally administrated mammalian target of rapamycin (mTOR) inhibitor. Several large-scale randomized controlled trials (RCTs) have demonstrated the survival benefits of everolimus at the dose of 10 mg/day for solid cancers. Furthermore, mTOR-inhibitor-based immunosuppression is associated with survival benefits for patients with hepatocellular carcinoma (HCC) who have received liver transplantation. However, a low rate of tumor reduction and some adverse events have been pointed out. This review summarizes the antitumor effects and adverse events of everolimus and evaluates its possible application in advanced HCC. For the meta-analysis of adverse events, we used the RCTs for solid cancers. The odds ratios of adverse events were calculated using the Peto method. Manypreclinical studies demonstrated that everolimus had antitumor effects such as antiproliferation and antiangiogenesis. However, some differences in the effects were observed among in vivo animal studies for HCC treatment. Meanwhile, clinical studies demonstrated that the response rate of single-agent everolimus was low, though survival benefits could be expected. The meta-analysis revealed the odds ratios (95% confidence interval [CI]) of stomatitis: 5.42 [4.31-6.73], hyperglycemia: 3.22 [2.37-4.39], anemia: 3.34 [2.37-4.67], pneumonitis: 6.02 [3.95-9.16], aspartate aminotransferase levels: 2.22 [1.37-3.62], and serum alanine aminotransferase levels: 2.94 [1.72-5.02], respectively. Everolimus at the dose of 10 mg/day significantly increased the risk of the adverse events. In order to enable its application to the standard conventional therapies of HCC, further studies are required to enhance the antitumor effects and manage the adverse events of everolimus. PMID:24403259

  6. Long-term mTOR inhibitors administration evokes altered calcium homeostasis and platelet dysfunction in kidney transplant patients.

    PubMed

    López, Esther; Berna-Erro, Alejandro; Bermejo, Nuria; Brull, José María; Martinez, Rocío; Garcia Pino, Guadalupe; Alvarado, Raul; Salido, Ginés María; Rosado, Juan Antonio; Cubero, Juan José; Redondo, Pedro Cosme

    2013-05-01

    The use of the mammal target of rapamycin (mTOR) inhibitors has been consolidated as the therapy of election for preventing graft rejection in kidney transplant patients, despite their immunosuppressive activity is less strong than anti-calcineurin agents like tacrolimus and cyclosporine A. Furthermore, as mTOR is widely expressed, rapamycin (a macrolide antibiotic produced by Streptomyces hygroscopicus) is recommended in patients presenting neoplasia due to its antiproliferative actions. Hence, we have investigated whether rapamycin presents side effects in the physiology of other cell types different from leucocytes, such as platelets. Blood samples were drawn from healthy volunteers and kidney transplant patients long-term medicated with rapamycin: sirolimus and everolimus. Platelets were either loaded with fura-2 or directly stimulated, and immunoassayed or fixed with Laemmli's buffer to perform the subsequent analysis of platelet physiology. Our results indicate that rapamycin evokes a biphasic time-dependent alteration in calcium homeostasis and function in platelets from kidney transplant patients under rapamycin regime, as demonstrated by the reduction in granule secretion observed and subsequent impairment of platelet aggregation in these patients compared with healthy volunteers. Platelet count was also reduced in these patients, thus 41% of patients presented thrombocytopenia. All together our results show that long-term administration of rapamycin to kidney transplant patients evokes alteration in platelet function. PMID:23577651

  7. Long-Term Use of Everolimus in Patients with Tuberous Sclerosis Complex: Final Results from the EXIST-1 Study

    PubMed Central

    Franz, David N.; Belousova, Elena; Sparagana, Steven; Bebin, E. Martina; Frost, Michael D.; Kuperman, Rachel; Witt, Olaf; Kohrman, Michael H.; Flamini, J. Robert; Wu, Joyce Y.; Curatolo, Paolo; de Vries, Petrus J.; Berkowitz, Noah; Niolat, Julie; Jóźwiak, Sergiusz

    2016-01-01

    Background Everolimus, a mammalian target of rapamycin (mTOR) inhibitor, has demonstrated efficacy in treating subependymal giant cell astrocytomas (SEGAs) and other manifestations of tuberous sclerosis complex (TSC). However, long-term use of mTOR inhibitors might be necessary. This analysis explored long-term efficacy and safety of everolimus from the conclusion of the EXIST-1 study (NCT00789828). Methods and Findings EXIST-1 was an international, prospective, double-blind, placebo-controlled phase 3 trial examining everolimus in patients with new or growing TSC-related SEGA. After a double-blind core phase, all remaining patients could receive everolimus in a long-term, open-label extension. Everolimus was initiated at a dose (4.5 mg/m2/day) titrated to a target blood trough of 5–15 ng/mL. SEGA response rate (primary end point) was defined as the proportion of patients achieving confirmed ≥50% reduction in the sum volume of target SEGA lesions from baseline in the absence of worsening nontarget SEGA lesions, new target SEGA lesions, and new or worsening hydrocephalus. Of 111 patients (median age, 9.5 years) who received ≥1 dose of everolimus (median duration, 47.1 months), 57.7% (95% confidence interval [CI], 47.9–67.0) achieved SEGA response. Of 41 patients with target renal angiomyolipomas at baseline, 30 (73.2%) achieved renal angiomyolipoma response. In 105 patients with ≥1 skin lesion at baseline, skin lesion response rate was 58.1%. Incidence of adverse events (AEs) was comparable with that of previous reports, and occurrence of emergent AEs generally decreased over time. The most common AEs (≥30% incidence) suspected to be treatment-related were stomatitis (43.2%) and mouth ulceration (32.4%). Conclusions Everolimus use led to sustained reduction in tumor volume, and new responses were observed for SEGA and renal angiomyolipoma from the blinded core phase of the study. These findings support the hypothesis that everolimus can safely reverse

  8. Targeting of tumor endothelial cells combining 2 Gy/day of X-ray with Everolimus is the effective modality for overcoming clinically relevant radioresistant tumors.

    PubMed

    Kuwahara, Yoshikazu; Mori, Miyuki; Kitahara, Shuji; Fukumoto, Motoi; Ezaki, Taichi; Mori, Shiro; Echigo, Seishi; Ohkubo, Yasuhito; Fukumoto, Manabu

    2014-04-01

    Radiotherapy is widely used to treat cancer because it has the advantage of physically and functionally conserving the affected organ. To improve radiotherapy and investigate the molecular mechanisms of cellular radioresistance, we established a clinically relevant radioresistant (CRR) cell line, SAS-R, from SAS cells. SAS-R cells continue to proliferate when exposed to fractionated radiation (FR) of 2 Gy/day for more than 30 days in vitro. A xenograft tumor model of SAS-R was also resistant to 2 Gy/day of X-rays for 30 days. The density of blood vessels in SAS-R tumors was higher than in SAS tumors. Everolimus, a mammalian target of rapamycin (mTOR) inhibitor, sensitized microvascular endothelial cells to radiation, but failed to radiosensitize SAS and SAS-R cells in vitro. Everolimus with FR markedly reduced SAS and SAS-R tumor volumes. Additionally, the apoptosis of endothelial cells (ECs) increased in SAS-R tumor tissues when both Everolimus and radiation were administered. Both CD34-positive and tomato lectin-positive blood vessel densities in SAS-R tumor tissues decreased remarkably after the Everolimus and radiation treatment. Everolimus-induced apoptosis of vascular ECs in response to radiation was also followed by thrombus formation that leads to tumor necrosis. We conclude that FR combined with Everolimus may be an effective modality to overcome radioresistant tumors via targeting tumor ECs. PMID:24464839

  9. Management of side effects of mTOR inhibitors in tuberous sclerosis patients.

    PubMed

    Sadowski, Krzysztof; Kotulska, Katarzyna; Jóźwiak, Sergiusz

    2016-06-01

    mTOR inhibitors represent a relatively new therapeutic option in the management of patients affected by tuberous sclerosis complex (TSC). Randomized clinical trials support the use of everolimus in the treatment of subependymal giant cell astrocytomas (SEGA) and renal angiomyolipomas (AML) related to TSC. Accumulating data suggest also systemic disease-modifying potential of mTOR inhibitors. Given that increasing number of patients with TSC receive mTOR inhibitors, the issue of adverse events associated with this therapy becomes practically important. In the present study we provide the overview of clinical manifestations and therapeutic options for the most common adverse events related to mTOR inhibitors in TSC patients. PMID:26891243

  10. The pros and the cons of mTOR inhibitors in kidney transplantation.

    PubMed

    Ponticelli, Claudio

    2014-02-01

    Sirolimus and its derivate everolimus are two immunosuppressive drugs with similar chemical structure that inhibit the proliferation of T cells by interfering with a serine-threonine kinase, called mTOR. Apart from their immunosuppressive effects, these agents may also inhibit endothelial intimal proliferation, the replication of cytomegalovirus, and the development of certain cancers. The main dose-dependent adverse events of mTOR inhibitors are hyperlipidemia, thrombocytopenia, mucositis, edema, and proteinuria. The use of mTOR inhibitors in renal transplantation may allow to reduce the doses of calcineurin inhibitors. Withdrawal of calcineurin inhibitors is also possible and may improve renal function, but some patients do not tolerate this regimen because of side effects. Further studies are needed to assess the role of mTOR inhibitors in the long-term. PMID:24377908

  11. A translational, pharmacodynamic and pharmacokinetic phase IB clinical study of everolimus in resectable non-small cell lung cancer

    PubMed Central

    Owonikoko, Taofeek K.; Ramalingam, Suresh S.; Miller, Daniel L.; Force, Seth D.; Sica, Gabriel L.; Mendel, Jennifer; Chen, Zhengjia; Rogatko, Andre; Tighiouart, Mourad; Harvey, R. Donald; Kim, Sungjin; Saba, Nabil F.; Pickens, Allan; Behera, Madhusmita; Fu, Robert W.; Rossi, Michael R.; Auffermann, William F.; Torres, William E.; Bechara, Rabih; Deng, Xingming; Sun, Shi-Yong; Fu, Haian; Gal, Anthony A.; Khuri, Fadlo R.

    2015-01-01

    Purpose Altered PI3K/mTOR pathway is implicated in lung cancer but mTOR inhibitors have failed to demonstrate efficacy in advanced lung cancer. We studied the pharmacodynamic effects of everolimus in resectable non-small cell lung cancer (NSCLC) to inform further development of these agents in lung cancer. Experimental Design We enrolled 33 patients and obtained baseline tumor biopsy and FDG-PET/CT imaging followed by everolimus treatment (5 or 10 mg daily, up to 28 days), or without intervening treatment for controls. Target modulation by everolimus was quantified in vivo and ex vivo by comparing metabolic activity on paired PET scans and expression of active phosphorylated forms of mTOR, Akt, S6, eIF4e, p70S6K, 4EBP1 and total Bim protein between pretreatment and post treatment tissue samples. Results There were 23 patients on the treatment arm and 10 controls; median age 64 years; 22 (67%) were adenocarcinomas. There was a dose-dependent reduction in metabolic activity (SUVmax: 29.0%, −21%, −24%; p=0.014), tumor size (10.1%, 5.8%, −11.6%; p=0.047), and modulation of S6 (−36.1, −13.7, −77.0; p=0.071) and pS6 (−41.25, −61.57, −47.21; p=0.063) in patients treated in the control, 5mg and 10mg cohorts respectively. Targeted DNA sequencing in all patients along with exome and whole transcriptome RNA-seq in an index patient with hypersensitive tumor was employed to further elucidate the mechanism of everolimus activity. Conclusion This “window-of-opportunity” study demonstrated measurable, dose-dependent, biologic, metabolic and antitumor activity of everolimus in early stage NSCLC. PMID:25673697

  12. Clinical experience and critical evaluation of the role of everolimus in advanced renal cell carcinoma

    PubMed Central

    Sun, Maxine; Abdollah, Firas; Schmitges, Jan; Jeldres, Claudio; Shariat, Shahrokh F; Perrotte, Paul; Karakiewicz, Pierre I

    2011-01-01

    The efficacy of sequential everolimus, an orally administered inhibitor of mammalian target of rapamycin (mTOR), was proven in a placebo-controlled phase III study, where median progression-free survival was 4.9 vs 1.9 months for placebo (hazard ratio: 0.33, P < 0.001). Placebo crossovers (80%) contaminated overall survival data. Adverse event discontinuation rate was of only 10% and health-adjusted quality-of-life was sustained. These data represent the first placebo-controlled evidence of efficacy for a sequentially used targeted agent. Everolimus resulted in the strongest hazard ratio ever recorded for progression-free survival, despite it being tested in a population with the most aggressive natural history ever recorded in all available phase III metastatic renal cell carcinoma trials. Everolimus use after exclusively one prior antivascular endothelial growth factor failure resulted in an even longer progression-free survival time (5.4 months) than in the entire population (4.9 months). These benefits should also be considered in the light of sustained and unimpaired health-related quality of life. Use in first line other than second or subsequent lines remains to be validated. PMID:24198635

  13. Biomarker signatures correlate with clinical outcome in refractory metastatic colorectal cancer patients receiving bevacizumab and everolimus.

    PubMed

    Liu, Yingmiao; Starr, Mark D; Brady, John C; Rushing, Christel; Bulusu, Anuradha; Pang, Herbert; Honeycutt, Wanda; Amara, Anthony; Altomare, Ivy; Uronis, Hope E; Hurwitz, Herbert I; Nixon, Andrew B

    2015-04-01

    A novel combination of bevacizumab and everolimus was evaluated in refractory colorectal cancer patients in a phase II trial. In this retrospective analysis, plasma samples from 49 patients were tested for over 40 biomarkers at baseline and after one or two cycles of drug administration. Analyte levels at baseline and change on-treatment were correlated with progression-free survival (PFS) and overall survival (OS) using univariate Cox proportional hazard modeling. Multivariable analyses were conducted using Cox modeling. Significant changes in multiple markers were observed following bevacizumab and everolimus treatment. Baseline levels of six markers significantly correlated with PFS and OS, including CRP, Gro-α, IGFBP-1, TF, ICAM-1, and TSP-2 (P < 0.05). At C2D1, changes of IGFBP-3, TGFβ-R3, and IGFBP-2 correlated with PFS and OS. Prognostic models were developed for OS and PFS (P = 0.0002 and 0.004, respectively). The baseline model for OS consisted of CRP, Gro-α, and TF, while the on-treatment model at C2D1 included IGFBP-2, IGFBP-3, and TGFβ-R3. These data demonstrated that multiple biomarkers were significantly modulated in response to bevacizumab and everolimus. Several markers correlated with both PFS and OS. Interestingly, these markers are known to be associated with inflammation and IGF signaling, key modulators of mTOR biology. PMID:25695956

  14. FDG-PET as a predictive biomarker for therapy with everolimus in metastatic renal cell cancer

    PubMed Central

    Chen, James L; Appelbaum, Daniel E; Kocherginsky, Masha; Cowey, Charles L; Kimryn Rathmell, Wendy; McDermott, David F; Stadler, Walter M

    2013-01-01

    Abstract The mTOR (mammalian target of rapamycin) inhibitor, everolimus, affects tumor growth by targeting cellular metabolic proliferation pathways and delays renal cell carcinoma (RCC) progression. Preclinical evidence suggests that baseline elevated tumor glucose metabolism as quantified by FDG-PET ([18F] fluorodeoxy-glucose positron emission tomography) may predict antitumor activity. Metastatic RCC (mRCC) patients refractory to vascular endothelial growth factor (VEGF) pathway inhibition were treated with standard dose everolimus. FDG-PET scans were obtained at baseline and 2 weeks; serial computed tomography (CT) scans were obtained at baseline and every 8 weeks. Maximum standardized uptake value (SUVmax) of the most FDG avid lesion, average SUVmax of all measured lesions and their corresponding 2-week relative changes were examined for association with 8-week change in tumor size. A total of 63 patients were enrolled; 50 were evaluable for the primary endpoint of which 48 had both PET scans. Patient characteristics included the following: 36 (72%) clear cell histology and median age 59 (range: 37–80). Median pre- and 2-week treatment average SUVmax were 6.6 (1–17.9) and 4.2 (1–13.9), respectively. Response evaluation criteria in solid tumors (RECIST)-based measurements demonstrated an average change in tumor burden of 0.2% (−32.7% to 35.9%) at 8 weeks. Relative change in average SUVmax was the best predictor of change in tumor burden (all evaluable P = 0.01; clear cell subtype P = 0.02), with modest correlation. Baseline average SUVmax was correlated with overall survival and progression-free survival (PFS) (P = 0.023; 0.020), but not with change in tumor burden. Everolimus therapy decreased SUVs on follow-up PET scans in mRCC patients, but changes were only modestly correlated with changes in tumor size. Thus, clinical use of FDG-PET-based biomarkers is challenged by high variability. In this phase II trial, FDG-PET was explored as a

  15. Everolimus Plus Exemestane for the Treatment of Advanced Breast Cancer: A Review of Subanalyses from BOLERO-21

    PubMed Central

    Hortobagyi, Gabriel N.

    2015-01-01

    Hormone receptor–positive breast cancer is typically managed with endocrine therapies. However, resistance to endocrine therapy results in disease progression in a large proportion of breast cancers. Through the understanding of the mechanisms of endocrine resistance, identification of implicated pathways and targets has led to the development of novel agents targeting these pathways. Phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway aberrations are common in breast cancer, with increased PI3K/AKT/mTOR signaling associated with resistance to endocrine and human epidermal growth factor receptor 2 (HER2)–targeted therapies. The mTOR inhibitor everolimus, in combination with exemestane, has been approved for patients with advanced hormone receptor–positive/HER2-negative breast cancer who progress on prior nonsteroidal aromatase inhibitor therapy based on results reported in the Breast Cancer Trials of Oral Everolimus-2 (BOLERO-2) study. This review will summarize the overall findings from BOLERO-2 and will consider available subanalyses by age, Asian origin, visceral or bone metastases, and prior therapy, with the aim of identifying populations most likely to benefit from everolimus therapy. The review will also summarize safety findings and their management and the effects of everolimus on quality of life. PMID:25810012

  16. Adjuvant Everolimus for Resected Kidney Cancer

    Cancer.gov

    In this clinical trial, patients with renal cell cancer who have undergone partial or complete nephrectomy will be randomly assigned to take everolimus tablets or matching placebo tablets daily for 54 weeks.

  17. Use of mTOR inhibitors in the treatment of breast cancer: an evaluation of factors that influence patient outcomes

    PubMed Central

    Jerusalem, Guy; Rorive, Andree; Collignon, Joelle

    2014-01-01

    Many systemic treatment options are available for advanced breast cancer, including endocrine therapy, chemotherapy, anti-human epidermal growth factor receptor 2 (HER2) therapy, and other targeted agents. Recently, everolimus, a mammalian target of rapamycin (mTOR) inhibitor, combined with exemestane, an aromatase inhibitor, has been approved in Europe and the USA for patients suffering from estrogen receptor-positive, HER2-negative advanced breast cancer previously treated by a nonsteroidal aromatase inhibitor, based on the results of BOLERO-2 (Breast cancer trials of OraL EveROlimus). This study showed a statistically significant and clinically meaningful improvement in median progression-free survival. Results concerning the impact on overall survival are expected in the near future. This clinically oriented review focuses on the use of mTOR inhibitors in breast cancer. Results reported with first-generation mTOR inhibitors (ridaforolimus, temsirolimus, everolimus) are discussed. The current and potential role of mTOR inhibitors is reported according to breast cancer subtype (estrogen receptor-positive HER2-negative, triple-negative, and HER2-positive ER-positive/negative disease). Everolimus is currently being evaluated in the adjuvant setting in high-risk estrogen receptor-positive, HER2-negative early breast cancer. Continuing mTOR inhibition or alternatively administering other drugs targeting the phosphatidylinositol-3-kinase/protein kinase B-mTOR pathway after progression on treatments including an mTOR inhibitor is under evaluation. Potential biomarkers to select patients showing a more pronounced benefit are reviewed, but we are not currently using these biomarkers in routine practice. Subgroup analysis of BOLERO 2 has shown that the benefit is consistent in all subgroups and that it is impossible to select patients not benefiting from addition of everolimus to exemestane. Side effects and impact on quality of life are other important issues discussed

  18. The Role of mTOR Inhibitors in the Treatment of Patients with Tuberous Sclerosis Complex: Evidence-based and Expert Opinions.

    PubMed

    Curatolo, Paolo; Bjørnvold, Marit; Dill, Patricia E; Ferreira, José Carlos; Feucht, Martha; Hertzberg, Christoph; Jansen, Anna; Jóźwiak, Sergiusz; Kingswood, J Christopher; Kotulska, Katarzyna; Macaya, Alfons; Moavero, Romina; Nabbout, Rima; Zonnenberg, Bernard A

    2016-04-01

    Tuberous sclerosis complex (TSC) is a genetic disorder arising from mutations in the TSC1 or TSC2 genes. The resulting over-activation of the mammalian target of rapamycin (mTOR) signalling pathway leaves patients with TSC susceptible to the growth of non-malignant tumours in multiple organs. Previously, surgery was the main therapeutic option for TSC. However, pharmacological therapy with mTOR inhibitors such as everolimus and sirolimus is now emerging as an alternate approach. Everolimus and sirolimus have already been shown to be effective in treating subependymal giant cell astrocytoma (SEGA) and renal angiomyolipoma (AML), and everolimus is currently being evaluated in treating TSC-related epilepsy. In November 2013 a group of European experts convened to discuss the current options and practical considerations for treating various manifestations of TSC. This article provides evidence-based recommendations for the treatment of SEGA, TSC-related epilepsy and renal AML, with a focus on where mTOR inhibitor therapy may be considered alongside other treatment options. Safety considerations regarding mTOR inhibitor therapy are also reviewed. With evidence of beneficial effects in neurological and non-neurological TSC manifestations, mTOR inhibitors may represent a systemic treatment for TSC. PMID:26927950

  19. Oscillatory mTOR inhibition and Treg increase in kidney transplantation.

    PubMed

    Sabbatini, M; Ruggiero, G; Palatucci, A T; Rubino, V; Federico, S; Giovazzino, A; Apicella, L; Santopaolo, M; Matarese, G; Galgani, M; Terrazzano, G

    2015-11-01

    Intracellular metabolic pathways dependent upon the mammalian target of rapamycin (mTOR) play a key role in immune-tolerance control. In this study, we focused on long-term mTOR-dependent immune-modulating effects in kidney transplant recipients undergoing conversion from calcineurin inhibitors (CNI) to mTOR inhibitors (everolimus) in a 1-year follow-up. The conversion to everolimus is associated with a decrease of neutrophils and of CD8(+) T cells. In addition, we observed a reduced production of interferon (IFN)-γ by CD8(+) T cells and of interleukin (IL)-17 by CD4(+) T lymphocytes. An increase in CD4(+) CD25(+) forkhead box protein 3 (FoxP3)(+) [regulatory T cell [(Treg)] numbers was also seen. Treg increase correlated with a higher proliferation rate of this regulatory subpopulation when compared with the CD4(+) FoxP3(-) effector counterpart. Basal phosphorylation level of S6 kinase, a major mTOR-dependent molecular target, was substantially maintained in patients treated with everolimus. Moreover, oscillations in serum concentration of everolimus were associated with changes in basal and activation-dependent S6 kinase phosphorylation of CD4(+) and CD8(+) T cells. Indeed, T cell receptor (TCR) triggering was observed to induce significantly higher S6 kinase phosphorylation in the presence of lower everolimus serum concentrations. These results unveil the complex mTOR-dependent immune-metabolic network leading to long-term immune-modulation and might have relevance for novel therapeutic settings in kidney transplants. PMID:26077103

  20. Molecular analysis of a male breast cancer patient with prolonged stable disease under mTOR/PI3K inhibitors BEZ235/everolimus

    PubMed Central

    Brannon, A. Rose; Frizziero, Melissa; Chen, David; Hummel, Jennifer; Gallo, Jorge; Riester, Markus; Patel, Parul; Cheung, Wing; Morrissey, Michael; Carbone, Carmine; Cottini, Silvia; Tortora, Giampaolo; Melisi, Davide

    2016-01-01

    The mTORC1 inhibitor everolimus (Afinitor/RAD001) has been approved for multiple cancer indications, including ER+/HER2− metastatic breast cancer. However, the combination of everolimus with the dual PI3K/mTOR inhibitor BEZ235 was shown to be more efficacious than either everolimus or BEZ235 alone in preclinical models. Herein, we describe a male breast cancer (MBC) patient who was diagnosed with hormone receptor-positive (HR+)/HER2− stage IIIA invasive ductal carcinoma and sequentially treated with chemoradiotherapy and hormonal therapy. Upon the development of metastases, the patient began a 200 mg twice-daily BEZ235 and 2.5 mg weekly everolimus combination regimen. The patient sustained a prolonged stable disease of 18 mo while undergoing the therapy, before his tumor progressed again. Therefore, we sought to both better understand MBC and investigate the underlying molecular mechanisms of the patient's sensitivity and subsequent resistance to the BEZ235/everolimus combination therapy. Genomic and immunohistochemical analyses were performed on samples collected from the initial invasive ductal carcinoma pretreatment and a metastasis postprogression on the BEZ235/everolimus combination treatment. Both tumors were relatively quiet genomically with no overlap to recurrent MBC alterations in the literature. Markers of PI3K/mTOR pathway hyperactivation were not identified in the pretreatment sample, which complements previous reports of HR+ female breast cancers being responsive to mTOR inhibition without this activation. The postprogression sample, however, demonstrated greater than fivefold increased estrogen receptor and pathogenesis-related protein expression, which could have constrained the PI3K/mTOR pathway inhibition by BEZ235/everolimus. Overall, these analyses have augmented the limited episteme on MBC genetics and treatment. PMID:27148582

  1. Reduced BCL2 and CCND1 mRNA expression in human cervical cancer HeLa cells treated with a combination of everolimus and paclitaxel

    PubMed Central

    Alp, Ebru; Onen, H. Ilke; Menevse, Sevda

    2016-01-01

    Aim of the study Cervical cancer is the second most common malignancy in women worldwide. Everolimus displays direct effects on growth and proliferation of cancer cells via inhibition of mammalian target of rapamycin (mTOR) protein, which is known to be associated with drug resistance. In this study, we aimed to investigate the effects of everolimus, gemcitabine, and paclitaxel in terms of cell viability and mRNA expression levels of GRP78, CCND1, CASP2, and BCL2 genes. Material and methods HeLa cells were treated with different doses of everolimus, gemcitabine, and paclitaxel. Cell viability was assessed using MTT assay, and obtained dose response curves were used for the calculations of inhibitory concentration (IC) values. At the end of the treatment times with selected doses, RNA isolation and cDNA synthesis were performed. Finally, GRP78, CCND1, CASP2, and BCL2 genes mRNA expression levels were analysed using quantitative PCR. Results The IC50 value of everolimus was 0.9 µM for 24-hour treatment. Moreover, the IC50 value of gemcitabine and paclitaxel was found to be around 18.1 µM and 7.08 µM, respectively. Everolimus, gemcitabine, and paclitaxel treatments alone did not change the GRP78, CCND1, BCL2 and CASP2 mRNA expression levels significantly. However, combined treatment of everolimus and paclitaxel significantly reduced BCL2 and CCND1 mRNA expression (p < 0.05). In contrast, this combination did not change GRP78 and CASP2 mRNA expression levels (p > 0.05). Conclusions Down-regulation of CCND1 and BCL2 expression may be an important mechanism by which everolimus increases the therapeutic window of paclitaxel in cervical cancers. PMID:27095936

  2. Peroxisome proliferator-activated receptor δ (PPARδ) induces estrogen receptor-positive mammary neoplasia through an inflammatory and metabolic phenotype linked to mTor activation

    PubMed Central

    Yuan, Hongyan; Lu, Jin; Xiao, Junfeng; Upadhyay, Geeta; Umans, Rachel; Kallakury, Bhaskar; Yin, Yuhzi; Fant, Michael E.; Kopelovich, Levy; Glazer, Robert I.

    2013-01-01

    The peroxisome proliferator-activated receptor-δ (PPARδ) regulates a multitude of physiological processes associated with glucose and lipid metabolism, inflammation and proliferation. One or more of these processes are potential risk factors for the ability of PPARδ agonists to promote tumorigenesis in the mammary gland. In the present study, we describe a new transgenic mouse model in which activation of PPARδ in the mammary epithelium by endogenous or synthetic ligands resulted in progressive histopathological changes that culminated in the appearance of estrogen receptor- and progesterone receptor-positive and ErbB2-negative infiltrating ductal carcinomas. Multiparous mice presented with mammary carcinomas after a latency of 12 months, and administration of the PPARδ ligand GW501516 reduced tumor latency to five months. Histopathological changes occurred concurrently with an increase in an inflammatory, invasive, metabolic and proliferative gene signature, including expression of the trophoblast gene, Plac1, beginning one week after GW501516 treatment, and remained elevated throughout tumorigenesis. The appearance of malignant changes correlated with a pronounced increase in phosphatidylcholine and lysophosphatidic acid metabolites, which coincided with activation of Akt and mTor signaling that were attenuated by treatment with the mTor inhibitor everolimus. Our findings are the first to demonstrate a direct role of PPARδ in the pathogenesis of mammary tumorigenesis, and suggest a rationale for therapeutic approaches to prevent and treat this disease. PMID:23811944

  3. Conversion to everolimus in liver transplant patients with renal dysfunction.

    PubMed

    Pérez, T; Segovia, R; Castro, L; Roblero, J P; Estela, R

    2011-01-01

    Calcineurin inhibitor (CNI) immunosuppressive therapy post-liver transplantation (OLT) is important to reduce graft rejection episodes. However, these drugs show important side effects, particularly renal dysfunction (RDF). Changing from CNI to a nonnephrotoxic drug, as mammalian target of rapamycin (mTOR) inhibitor may solve the problem. Our objective was to evaluate renal function (RF) among liver transplant patients initially receiving CNI, among whom the patients with RDF were converted completely or partially to an mTOR inhibitor like everolimus (EVE). We performed a prospective study in liver transplant patients from 2000 to 2009. Creatinine levels and creatinine clearances (Cockroft-Gault) expressed as mean values ± standard deviations were measured pre- and postswitch for comparisons using Wilcoxon nonparametric tests. Six patients were converted fully or partially to EVE. Their mean age at the moment of introducing the new therapy was 52.2 ± 13.6 years (range = 28-60). Immunosuppression time prior to switching from CNI to EVE was 23.8 ± 26.6 months (range = 6-70). Postconversion follow-up was 25.8 ± 16.5 months (range = 8-42). All patients showed improvement in RF. The creatinine level improvement was significant (P = .03) namely, from a mean of 2.26 ± 0.49 to 1.21 ± 0.57 mg/dL. Glomerular filtration rate improved from a mean of 40 ± 15.13 to 72.60 ± 17.3 mL/min/m(2) (P = .03). Conversion from CNI to EVE improved creatinine concentrations and creatinine clearances with long-term effects free of graft rejection. PMID:21839260

  4. A single arm phase 1b study of everolimus and sunitinib in patients with advanced renal cell carcinoma (RCC)

    PubMed Central

    Kanesvaran, R.; Watt, K.; Turnbull, J. D.; Armstrong, A. J.; Cohen-Wolkowiez, M.; George, D. J.

    2016-01-01

    Background Everolimus ,an oral inhibitor of mammalian target of rapamycin (mTOR), and sunitinib, an oral inhibitor of VEGF/PDGF receptor tyrosine kinase signaling, have both been shown to provide clinical benefit in patients with advanced RCC. We sought to determine the safety and efficacy of combination therapy with these agents in patients with advanced RCC. Methods We conducted a phase Ib dose escalation trial of sunitinib and everolimus in patients with advanced metastatic RCC. Prior nephrectomy was required, and prior radiation or chemotherapy other than VEGF/mTOR-based therapies was permitted. The primary endpoint was to determine the MTD/recommended phase 2 dose. Results A total of 4 out of a planned 30 subjects were enrolled in this study (M:F= 2:2; mean age 52 years, 50% with KPS <80). The first three patients were enrolled on a 4+2 dosing schedule of daily sunitinib 50 mg and weekly everolimus 30 mg. Mean time on drug was 99 days. One partial response was seen. Toxicities included mucositis, thrombocytopenia, anemia, fatigue, dehydration and hypoglycemia. Due to multiple grade 3–4 toxicities, the protocol was amended to 2+1 dosing of sunitinib 37.5 mg and daily everolimus 5mg. The first patient on this schedule died from multi-organ failure with septic shock after 1 cycle of treatment. Subsequently, the study was closed. Pharmacokinetics results inconclusively suggest that toxicities could be attributed to the drug exposure. Conclusions Combined use of everolimus and sunitinib in the treatment of mRCC was not well tolerated in this small cohort. PMID:26174223

  5. [Concurrent association of reirradiation therapy with everolimus for lymph node metastasis of gastroesophageal junction cancer: a case report].

    PubMed

    Pernin, V; Beuzeboc, P; Peurien, D; Louvet, C; Kirova, Y

    2014-11-01

    Advanced gastric cancer or gastro-oesophageal junction cancer after a failure of first line chemotherapy have poor outcome. Hereby, we present the first patient treated by radiotherapy with concurrent everolimus, a mTor inhibitor, for a reirradiation of metastasis invading left axillary, infraclavicular and supraclavicular lymph nodes in progression despite several lines of chemotherapy. After 6 months of follow-up, this association provided a satisfactory anti-tumor efficiency and tolerance. Nevertheless, clinical trials are needed in order to confirm this strategy for the treatment of gastric cancer metastasis. PMID:24981410

  6. Phase I Study of the Anti-IGF-1R Monoclonal Antibody, Cixutumumab in Combination with Everolimus and Octreotide LAR in Advanced Low to Intermediate Grade Neuroendocrine Tumors

    PubMed Central

    Dasari, Arvind; Phan, Alexandria; Gupta, Sanjay; Rashid, Asif; Yeung, Sai-ChingJim; Hess, Kenneth; Chen, Helen; Tarco, Emily; Chen, Huiqin; Wei, Caimiao; Anh-Do, Kim; Halperin, Daniel; Meric-Bernstam, Funda; Yao, James

    2015-01-01

    Preclinical data suggest multiple roles for the insulin like growth factor receptor 1 (IGF-1R) in neuroendocrine tumors (NET) including mediating resistance to mTOR inhibitors. Everolimus, an oral mTOR inhibitor and octreotide LAR are approved for subgroups of well differentiated NET. The primary objective was to establish the safety and recommended phase II dose (RP2D) of cixutumumab, a monoclonal antibody against IGF-1R with everolimus and octreotide LAR. Patients with well differentiated NET were treated with everolimus 10 mg po daily, octreotide LAR 20 mg IM every 21 days and escalating doses of cixutumumab. An expansion cohort was enrolled at RP2D. Correlative studies included evaluation of mTOR pathway inhibition in paired tumor biopsies and effects of this combination on metabolism per indirect calorimetry. 19 patients with progressive disease, including 9 to the expansion portion were enrolled. 2 patients had dose limiting toxicities of grade 3 mucositis at cixutumumab 15 mg/kg. Long term tolerance at RP2D was problematic, the most common ≥ grade 3 adverse event (AE) being fatigue. One patient with metastatic insulinoma had a confirmed partial response while seventeen had stable disease. Median progression free survival was 43.6 weeks and median overall survival was 25.5 months. Conclusions The RP2D of this combination per predefined study protocol cixutumumab iv 10 mg/kg, octreotide LAR 20 mg IM every 21 days plus everolimus 10 mg po daily is associated with non-DLT toxicities limiting long term tolerance. Although a signal of activity was noted in this study, this will need to be reconciled with limited tolerance of the combination and data from larger studies of anti-IGF-1R monoclonal antibodies in NET that have been disappointing. PMID:25900182

  7. Loss of Tuberous Sclerosis Complex 2 (TSC2) Is Frequent in Hepatocellular Carcinoma and Predicts Response to mTORC1 Inhibitor Everolimus.

    PubMed

    Huynh, Hung; Hao, Huai-Xiang; Chan, Stephen L; Chen, David; Ong, Richard; Soo, Khee Chee; Pochanard, Panisa; Yang, David; Ruddy, David; Liu, Manway; Derti, Adnan; Balak, Marissa N; Palmer, Michael R; Wang, Yan; Lee, Benjamin H; Sellami, Dalila; Zhu, Andrew X; Schlegel, Robert; Huang, Alan

    2015-05-01

    Hepatocellular carcinoma (HCC) is the third leading cause of cancer deaths worldwide and hyperactivation of mTOR signaling plays a pivotal role in HCC tumorigenesis. Tuberous sclerosis complex (TSC), a heterodimer of TSC1 and TSC2, functions as a negative regulator of mTOR signaling. In the current study, we discovered that TSC2 loss-of-function is common in HCC. TSC2 loss was found in 4 of 8 HCC cell lines and 8 of 28 (28.6%) patient-derived HCC xenografts. TSC2 mutations and deletions are likely to be the underlying cause of TSC2 loss in HCC cell lines, xenografts, and primary tumors for most cases. We further demonstrated that TSC2-null HCC cell lines and xenografts had elevated mTOR signaling and, more importantly, were significantly more sensitive to RAD001/everolimus, an mTORC1 inhibitor. These preclinical findings led to the analysis of TSC2 status in HCC samples collected in the EVOLVE-1 clinical trial of everolimus using an optimized immunohistochemistry assay and identified 15 of 139 (10.8%) samples with low to undetectable levels of TSC2. Although the sample size is too small for formal statistical analysis, TSC2-null/low tumor patients who received everolimus tended to have longer overall survival than those who received placebo. Finally, we performed an epidemiology survey of more than 239 Asian HCC tumors and found the frequency of TSC2 loss to be approximately 20% in Asian HBV(+) HCC. Taken together, our data strongly argue that TSC2 loss is a predictive biomarker for the response to everolimus in HCC patients. PMID:25724664

  8. Novel agents and associated toxicities of inhibitors of the pi3k/Akt/mtor pathway for the treatment of breast cancer

    PubMed Central

    Chia, S.; Gandhi, S.; Joy, A.A.; Edwards, S.; Gorr, M.; Hopkins, S.; Kondejewski, J.; Ayoub, J.P.; Califaretti, N.; Rayson, D.; Dent, S.F.

    2015-01-01

    The pi3k/Akt/mtor (phosphatidylinositol 3 kinase/ Akt/mammalian target of rapamycin) signalling pathway is an established driver of oncogenic activity in human malignancies. Therapeutic targeting of this pathway holds significant promise as a treatment strategy. Everolimus, an mtor inhibitor, is the first of this class of agents approved for the treatment of hormone receptor–positive, human epidermal growth factor receptor 2–negative advanced breast cancer. Everolimus has been associated with significant improvements in progression-free survival; however, it is also associated with increased toxicity related to its specific mechanism of action. Methods A comprehensive review of the literature conducted using a focused medline search was combined with a search of current trials at http://ClinicalTrials.gov/. Summary tables of the toxicities of the various classes of pi3k/Akt/mtor inhibitors were created. A broad group of Canadian health care professionals was assembled to review the data and to produce expert opinion and summary recommendations for possible best practices in managing the adverse events associated with these pathway inhibitors. Results Differing toxicities are associated with the various classes of pi3k/Akt/mtor pathway inhibitors. The most common unique adverse events observed in everolimus clinical trials in breast cancer include stomatitis (all grades: approximately 60%), noninfectious pneumonitis (15%), rash (40%), hyperglycemia (15%), and immunosuppression (40%). To minimize grades 3 and 4 toxicities and to attempt to attain optimal outcomes, effective management of those adverse events is critical. Management should be interdisciplinary and should use approaches that include education, early recognition, active intervention, and potentially prophylactic strategies. Discussion Everolimus likely represents the first of many complex oral targeted therapies for the treatment of breast cancer. Using this agent as a template, it is essential to

  9. Everolimus improves memory and learning while worsening depressive- and anxiety-like behavior in an animal model of depression.

    PubMed

    Russo, Emilio; Leo, Antonio; Crupi, Rosalia; Aiello, Rossana; Lippiello, Pellegrino; Spiga, Rosangela; Chimirri, Serafina; Citraro, Rita; Cuzzocrea, Salvatore; Constanti, Andrew; De Sarro, Giovambattista

    2016-07-01

    Everolimus (EVR) is an orally-administered rapamycin analog that selectively inhibits the mammalian target of rapamycin (mTOR) kinase (mainly mTORC1 and likely mTORC2) and the related signaling pathway. mTOR is a serine/threonine protein kinase regulating multiple important cellular functions; dysfunction of mTOR signaling has also been implicated in the pathophysiology of several neurological, neurodegenerative, developmental and cognitive disorders. EVR is widely used as an anti-neoplastic therapy and more recently in children with tuberous sclerosis complex (TSC). However, no clear correlation exists between EVR use and development of central side effects e.g. depression, anxiety or cognitive impairment. We studied the effects of a 3 weeks administration of EVR in mice chronically treated with betamethasone 21-phosphate disodium (BTM) as a model of depression and cognitive decline. EVR treatment had detrimental effects on depressive- and anxiety-like behavior while improving cognitive performance in both control (untreated) and BTM-treated mice. Such effects were accompanied by an increased hippocampal neurogenesis and synaptogenesis. Our results therefore might support the proposed pathological role of mTOR dysregulation in depressive disorders and confirm some previous data on the positive effects of mTOR inhibition in cognitive decline. We also show that EVR, possibly through mTOR inhibition, may be linked to the development of anxiety. The increased hippocampal neurogenesis by EVR might explain its ability to improve cognitive function or protect from cognitive decline. Our findings suggest some caution in the use of EVR, particularly in the developing brain; patients should be carefully monitored for their psychiatric/neurological profiles in any clinical situation where an mTOR inhibitor and in particular EVR is used e.g. cancer treatment, TSC or immunosuppression. PMID:27019134

  10. A Case of Disease Improvement after Treatment with Everolimus plus Exemestane in a Patient with Hormone Receptor-Positive Metastatic Breast Cancer with Bone Metastases

    PubMed Central

    Beck, J. Thaddeus; Mantooth, Ryan

    2015-01-01

    Breast cancer is one of the most frequently diagnosed cancers and a leading cause of death in women worldwide. Despite significant advances in the treatment of hormone receptor-positive breast cancer, tumor metastasis occurs frequently and is associated with poor long-term prognosis. The mammalian target of rapamycin (mTOR) pathway plays a central role in cancer cell growth, proliferation, and resistance to endocrine therapies. Therefore, mTOR inhibitors such as everolimus in combination with nonsteroidal aromatase inhibitors might reverse endocrine resistance and improve clinical outcomes in patients. Here, we report on a case of infiltrating lobular carcinoma of the breast with metastases to the bone. Histopathologic analysis showed that the patient was estrogen and progesterone receptor positive and human epidermal growth factor-2 negative. This case represents the clinical spectrum of complications caused by metastasis: the patient experienced a considerable amount of skeletal-related complications, had previously received chemotherapy, and experienced disease progression while taking nonsteroidal aromatase inhibitors. After treatment with oral everolimus 10 mg daily plus oral exemestane 25 mg daily, the patient's disease was ameliorated. Combination therapy was well tolerated, with minimal adverse effects that were manageable with concomitant medications. Although further analyses in larger populations are necessary, the addition of everolimus to exemestane might provide an effective new treatment option for patients with bone metastasis. PMID:25848360

  11. Everolimus and intensive behavioral therapy in an adolescent with tuberous sclerosis complex and severe behavior☆☆☆★

    PubMed Central

    Gipson, Tanjala T.; Jennett, Heather; Wachtel, Lee; Gregory, Mary; Poretti, Andrea; Johnston, Michael V.

    2013-01-01

    Background Self-injury and aggression have been reported in individuals with TSC (tuberous sclerosis complex), yet few data exist about treatment. Everolimus, an mTOR inhibitor, has been FDA-approved for subependymal giant cell astrocytomas (SEGAs) and renal angiomyolipomas in TSC. However, clinical use of everolimus with direct, real-time observations of self-injury and aggression in an individual with TSC has not been reported. Methods During an inpatient admission to a neurobehavioral unit, real-time measurements of behaviors and seizures were recorded. An interdisciplinary team used these data to make treatment decisions and applied behavioral and pharmacological treatments, one at a time, in order to evaluate their effects. Results Aggression and self-injury improved with applied behavioral analysis (ABA), lithium, and asenapine. Improvements in SEGA size, facial angiofibromas, seizures, and the most stable low rates of self-injury were observed during the interval of treatment with everolimus. Conclusion Mechanism-based treatments in the setting of an evidence-based behavioral and psychopharmacological intervention program may be a model with utility for characterization and treatment of individuals with severe behavior and TSC. PMID:25667844

  12. Blood concentrations of everolimus are markedly increased by ketoconazole.

    PubMed

    Kovarik, J M; Beyer, D; Bizot, M N; Jiang, Q; Shenouda, M; Schmouder, R L

    2005-05-01

    The authors sought to quantify the influence of the CYP3A and P-glycoprotein inhibitor ketoconazole on the pharmacokinetics of everolimus in healthy subjects. This was a 2-period, single-sequence, crossover study in 12 healthy subjects. In period 1, subjects received the reference treatment of a single 2-mg dose of everolimus. In period 2, they received the test treatment of ketoconazole 200 mg twice daily for a total of 8 days and a single dose of everolimus coadministered on the fourth day of ketoconazole therapy. The test/reference ratio and 90% confidence interval were derived for everolimus maximum concentration and area under the curve. During ketoconazole coadministration, everolimus maximum concentration increased 3.9-fold (90% confidence interval, 3.4-4.6) from 15 +/- 4 ng/mL to 59 +/- 13 ng/mL. Everolimus area under the curve increased 15.0-fold (90% confidence interval, 13.6-16.6) from 90 +/- 23 ng*h/mL to 1324 +/- 232 ng*h/mL. Everolimus half-life was prolonged by 1.9-fold from 30 +/- 4 hours to 56 +/- 5 hours. Everolimus did not appear to alter ketoconazole predose concentrations. Given the magnitude of this drug interaction, use of ketoconazole should be avoided if possible in everolimus-treated patients. PMID:15831774

  13. mTOR Inhibitors Control the Growth of EGFR Mutant Lung Cancer Even after Acquiring Resistance by HGF

    PubMed Central

    Ishikawa, Daisuke; Takeuchi, Shinji; Nakagawa, Takayuki; Sano, Takako; Nakade, Junya; Nanjo, Shigeki; Yamada, Tadaaki; Ebi, Hiromichi; Zhao, Lu; Yasumoto, Kazuo; Nakamura, Takahiro; Matsumoto, Kunio; Kagamu, Hiroshi; Yoshizawa, Hirohisa; Yano, Seiji

    2013-01-01

    Resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), gefitinib and erlotinib, is a critical problem in the treatment of EGFR mutant lung cancer. Several mechanisms, including bypass signaling by hepatocyte growth factor (HGF)-triggered Met activation, are implicated as mediators of resistance. The mammalian target of rapamycin (mTOR), is a downstream conduit of EGFR and MET signaling, and is thus considered a therapeutically attractive target in the treatment of various types of cancers. The purpose of this study was to examine whether 2 clinically approved mTOR inhibitors, temsirolimus and everolimus, overcome HGF-dependent resistance to EGFR-TKIs in EGFR mutant lung cancer cells. Both temsirolimus and everolimus inhibited the phosphorylation of p70S6K and 4E-BP1, which are downstream targets of the mTOR pathway, and reduced the viability of EGFR mutant lung cancer cells, PC-9, and HCC827, even in the presence of HGF in vitro. In a xenograft model, temsirolimus suppressed the growth of PC-9 cells overexpressing the HGF-gene; this was associated with suppression of the mTOR signaling pathway and tumor angiogenesis. In contrast, erlotinib did not suppress this signaling pathway or tumor growth. Multiple mechanisms, including the inhibition of vascular endothelial growth factor production by tumor cells and suppression of endothelial cell viability, contribute to the anti-angiogenic effect of temsirolimus. These findings indicate that mTOR inhibitors may be useful for controlling HGF-triggered EGFR-TKI resistance in EGFR mutant lung cancer, and they provide the rationale for clinical trials of mTOR inhibitors in patients stratified by EGFR mutation and HGF expression status. PMID:23690929

  14. mTOR and PDGF pathway blockade inhibits liver metastasis of colorectal cancer by modulating the tumor microenvironment.

    PubMed

    Yuge, Ryo; Kitadai, Yasuhiko; Shinagawa, Kei; Onoyama, Mieko; Tanaka, Shinji; Yasui, Wataru; Chayama, Kazuaki

    2015-02-01

    Tumor growth and metastasis are not determined by cancer cells alone but also by a variety of stromal cells, and platelet-derived growth factor receptors (PDGF-Rs) are overexpressed by various stromal cell populations. Activation of PI3K-AKT-mTOR signaling is frequently observed in many cancer types. We investigated whether the mTOR inhibitor everolimus, alone or in combination with the PDGF-R tyrosine kinase inhibitor nilotinib, can inhibit growth and metastasis of human colon cancer. The effects of nilotinib and everolimus on tumor growth and metastasis were examined in an orthotopic mouse model of human colon cancer and a model of liver metastasis. After treatment with nilotinib (versus distilled water), the stromal reaction of xenografts growing in the cecal wall and liver was significantly decreased. After treatment with everolimus, the stromal reaction did not decrease, but tumor cell proliferation and microvessel density decreased. With the two drugs in combination, both stromal reaction and tumor cell proliferation decreased and apoptosis of tumor cells increased, resulting in remarkable inhibition of tumor growth at both the orthotopic and the metastatic site. Concurrent inhibition of tumor cells and activated stromal cells by a PDGF-R tyrosine kinase inhibitor and an mTOR inhibitor used in combination may represent a novel therapeutic approach for colorectal cancer. PMID:25478811

  15. The combination of IκB kinase β inhibitor and everolimus modulates expression of interleukin-10 in human T-cell lymphotropic virus type-1-infected T cells.

    PubMed

    Nishioka, Chie; Ikezoe, Takayuki; Yang, Jing; Udaka, Keiko; Yokoyama, Akihito

    2013-03-01

    Adult T-cell leukaemia-lymphoma (ATLL) is an aggressive malignancy of CD4(+)  CD25(+) T lymphocytes, characterized by a severely compromised immunosystem, in which the human T-cell lymphotropic virus type 1 (HTLV-1) has been recognized as the aetiological agent. This study found that an IκB kinase β (IKKβ) inhibitor Bay11-7082 inactivated mammalian target of rapamycin (mTOR), signal transducer and activator of transcription 3 and transcription factor nuclear factor-κB in HTLV-1-infected T cells; this was significantly enhanced in the presence of the mTOR inhibitor everolimus. In addition, Bay11-7082 decreased production of the immunosuppressive cytokine interleukin-10 (IL-10), which was further down-regulated when Bay11-7082 was combined with evelolimus in HTLV-1-infected T and ATLL cells isolated from patients. Interleukin-10 is known to inhibit maturation and the antigen-presenting function of dendritic cells (DCs). The culture media of HTLV-1-infected MT-1 cells, which contained a large amout of IL-10, hampered tumour necrosis factor-α-induced maturation of DCs isolated from healthy volunteers. Culture supernatant of MT-1 cells treated with a combination of Bay11-7082 and everolimus augmented maturation of DCs in association with a decrease in production of IL-10 and enhanced the allostimulatory function of DCs. Similarly, when DCs isolated from patients with ATLL were treated with the combination of Bay11-7082 and everolimus, they were fully matured and their capability to stimulate proliferation of lymphocytes was augmented. Taken together, the combination of Bay11-7082 and everolimus might exhibit immunostimulatory properties in HTLV-1-infected T and ATLL cells isolated from patients, and this combination may be potentially therapeutic to regain the compromised immunosystem in ATLL patients. PMID:23278479

  16. Antidiabetic Drug Metformin Prevents Progression of Pancreatic Cancer by Targeting in Part Cancer Stem Cells and mTOR Signaling12

    PubMed Central

    Mohammed, Altaf; Janakiram, Naveena B; Brewer, Misty; Ritchie, Rebekah L; Marya, Anuj; Lightfoot, Stan; Steele, Vernon E; Rao, Chinthalapally V

    2013-01-01

    Epidemiologic studies have shown that diabetes mellitus is associated positively with increased risk of pancreatic ductal adenocarcinoma (PDAC), and recent meta-analysis studies showed that metformin, reduces the risk of pancreatic cancer (PC). We tested the effects of metformin on pancreatic intraepithelial neoplasia (PanIN) and their progression to PDAC in p48Cre/+.LSL-KrasG12D/+ transgenic mice. Mice fed control diet showed 80% and 62% incidence of PDAC in males and females, respectively. Male mice showed 20% and 26%, and female mice showed 7% and 0% PDAC incidence with 1000- and 2000-ppm metformin treatments, respectively. Both doses of metformin decreased pancreatic tumor weights by 34% to 49% (P < 0.03–0.001). The drug treatment caused suppression of PanIN 3 (carcinoma in situ) lesions by 28% to 39% (P < .002) and significant inhibition of carcinoma spread in the pancreas. The pancreatic tissue and/or serum of mice fed metformin showed a significant inhibition of mammalian target of rapamycin (mTOR), extracellular signal-regulated kinases (ERK), phosphorylated extracellular signal-regulated kinases (pErk), and insulin-like growth factor 1 (IGF-1) with an increase in phosphorylated 5′ adenosine monophosphate kinase (pAMPK), tuberous sclerosis complex 1 (TSC1, TSC2), C-protein and an autophagy related protein 2 (ATG2). The cancer stem cell (CSC) markers were significantly decreased (P < 0.04–0.0002) in the pancreatic tissue. These results suggest that biologic effects of metformin are mediated through decreased CSC markers cluster of differentiation 44 (CD44 and CD133), aldehyde dehydrogenase isoform 1 (ALDH1), and epithelial cell adhesion molecule (EPCAM) and modulation of the mTOR signaling pathway. Our preclinical data indicate that metformin has significant potential for use in clinical trials for PC chemoprevention. PMID:24466367

  17. Addition of Everolimus Post VEGFR Inhibition Treatment Failure in Advanced Sarcoma Patients Who Previously Benefited from VEGFR Inhibition: A Case Series

    PubMed Central

    Hays, John L.; Chen, James L.

    2016-01-01

    Background Patients with metastatic sarcoma who progress on vascular endothelial growth factor receptor inhibitors (VEGFRi) have limited treatment options. Upregulation of the mTOR pathway has been demonstrated to be a means of resistance to targeted VEGFRi in metastatic sarcoma. Patients and methods Retrospective cohort study to evaluate the clinical benefit at four months of combining mTOR inhibition (mTORi) via everolimus with VEGFRi in patients who have derived benefit from single-agent VEGFRi but have progressed. Patients with recurrent, metastatic soft tissue or bone sarcomas who progressed after deriving clinical benefit to VEGFRi beyond 12 weeks were continued on VEGFRi with the addition of everolimus (5 mg daily). Progression free survival was measured from start of VEGFRi to disease progression on single agent VEGFRi as well as from the addition of everolimus therapy to disease progression or drug discontinuation due to toxicity. Clinical benefit was defined as stable disease or partial response at 4 months. Results Nine patients were evaluated. Two patients did not tolerate therapy due to GI toxicity and one elected to discontinue therapy. Of the remaining six patients, the clinical benefit rate at four months was 50%. Progression free survival (PFS) for these patients was 3.1 months ranging from 0.5 to 7.2 months with one patient remaining on combination therapy. Conclusion In this heavily pre-treated, advanced sarcoma population, the addition of mTOR inhibition to VEGFRi based therapy resulted in a clinical benefit for a subset of patients. Prospective studies will be needed to verify these results. PMID:27295141

  18. Mammalian target of rapamycin (mTOR) inhibitors and combined chemotherapy in breast cancer: a meta-analysis of randomized controlled trials

    PubMed Central

    Qiao, Longwei; Liang, Yuting; Mira, Ranim R; Lu, Yaojuan; Gu, Junxia; Zheng, Qiping

    2014-01-01

    The mammalian target of rapamycin (mTOR) inhibitor, in combination with other chemotherapeutic drugs, has been used for treatment of breast cancer that develops resistance to endocrine therapy. However, the efficacy and safety need further evaluation. Here, we report a meta-analysis of randomized controlled trials (RCT) in breast cancer patients undergoing chemotherapy using steroid (exemestane) or nonsteroid (letrozole) aromatase inhibitors with or without mTOR inhibitors (everolimus). The overall response rate (ORR), progression-free survival (PFS), clinical benefi;t rate with 95% confidence interval (CI), and the major toxicities/adverse effects were analyzed. Data were extracted from twelve studies that meet the selection criteria. Among these, six studies that enrolled 3693 women received treatment of everolimus plus exemestane, or placebo with exemestane. The results showed that everolimus plus exemestane significantly increased the ORR relative risk (relative risk = 9.18, 95% CI = 5.21-16.15), PFS hazard ratio (hazard ratio = 0.44, 95% CI = 0.41-0.48), and clinical benefi;t rate (relative risk = 1.92, 95% CI 1.69-2.17) compared to placebo control, while the risks of stomatitis, rash, hyperglycemia, diarrhea, fatigue, anorexia and pneumonitis also increased. Three studies that enrolled 715 women who received everolimus as neoadjuvant therapy were analyzed. Compared to chemotherapy with placebo, chemotherapy plus everolimus did not increase the ORR relative risk (relative risk = 0.90, 95% CI = 0.77-1.05). Meanwhile, two other studies that enrolled 2104 women examined the efficacy of temsirolimus (or placebo control) plus letrozole. The results indicated that emsirolimus plus letrozole did not increase the ORR relative risk and clinical benefi;t rate (p > 0.05). Together, these data suggest that the combined mTOR inhibitor (everolimus) plus endocrine therapy (exemestane) is superior to endocrine therapy alone. As a neoadjuvant, everolimus did not increase the

  19. Vascular disruption in combination with mTOR inhibition in renal cell carcinoma.

    PubMed

    Ellis, Leigh; Shah, Preeti; Hammers, Hans; Lehet, Kristin; Sotomayor, Paula; Azabdaftari, Gissou; Seshadri, Mukund; Pili, Roberto

    2012-02-01

    Renal cell carcinoma (RCC) is an angiogenesis-dependent and hypoxia-driven malignancy. As a result, there has been an increased interest in the use of antiangiogenic agents for the management of RCC in patients. However, the activity of tumor-vascular disrupting agents (tumor-VDA) has not been extensively examined against RCC. In this study, we investigated the therapeutic efficacy of the tumor-VDA ASA404 (DMXAA, 5,6-dimethylxanthenone-4-acetic acid, or vadimezan) in combination with the mTOR inhibitor everolimus (RAD001) against RCC. In vitro studies were carried out using human umbilical vein endothelial cells and in vivo studies using orthotopic RENCA tumors and immunohistochemical patient tumor-derived RCC xenografts. MRI was used to characterize the vascular response of orthotopic RENCA xenografts to combination treatment. Therapeutic efficacy was determined by tumor growth measurements and histopathologic evaluation. ASA404/everolimus combination resulted in enhanced inhibition of endothelial cell sprouting in the 3-dimensional spheroid assay. MRI of orthotopic RENCA xenografts revealed an early increase in permeability 4 hours posttreatment with ASA404, but not with everolimus. Twenty-four hours after treatment, a significant reduction in blood volume was observed with combination treatment. Correlative CD31/NG2 staining of tumor sections confirmed marked vascular damage following combination therapy. Histologic sections showed extensive necrosis and a reduction in the viable rim following combination treatment compared with VDA treatment alone. These results show the potential of combining tumor-VDAs with mTOR inhibitors in RCC. Further investigation into this novel combination strategy is warranted. PMID:22084164

  20. Vascular Disruption in Combination with mTOR Inhibition in Renal Cell Carcinoma

    PubMed Central

    Ellis, Leigh; Shah, Preeti; Hammers, Hans; Lehet, Kristin; Sotomayor, Paula; Azabdaftari, Gissou; Seshadri, Mukund; Pili, Roberto

    2013-01-01

    Renal cell carcinoma (RCC) is an angiogenesis-dependent and hypoxia-driven malignancy. As a result, there has been an increased interest in the use of antiangiogenic agents for the management of RCC in patients. However, the activity of tumor-vascular disrupting agents (tumor-VDA) has not been extensively examined against RCC. In this study, we investigated the therapeutic efficacy of the tumor-VDA ASA404 (DMXAA, 5,6-dimethylxanthenone-4-acetic acid, or vadimezan) in combination with the mTOR inhibitor everolimus (RAD001) against RCC. In vitro studies were carried out using human umbilical vein endothelial cells and in vivo studies using orthotopic RENCA tumors and immunohistochemical patient tumor-derived RCC xenografts. MRI was used to characterize the vascular response of orthotopic RENCA xenografts to combination treatment. Therapeutic efficacy was determined by tumor growth measurements and histopathologic evaluation. ASA404/everolimus combination resulted in enhanced inhibition of endothelial cell sprouting in the 3-dimensional spheroid assay. MRI of orthotopic RENCA xenografts revealed an early increase in permeability 4 hours posttreatment with ASA404, but not with everolimus. Twenty-four hours after treatment, a significant reduction in blood volume was observed with combination treatment. Correlative CD31/NG2 staining of tumor sections confirmed marked vascular damage following combination therapy. Histologic sections showed extensive necrosis and a reduction in the viable rim following combination treatment compared with VDA treatment alone. These results show the potential of combining tumor-VDAs with mTOR inhibitors in RCC. Further investigation into this novel combination strategy is warranted. PMID:22084164

  1. The effect of everolimus on renal angiomyolipoma in patients with tuberous sclerosis complex being treated for subependymal giant cell astrocytoma: subgroup results from the randomized, placebo-controlled, Phase 3 trial EXIST-1

    PubMed Central

    Kingswood, J. Chris; Jozwiak, Sergiusz; Belousova, Elena D.; Frost, Michael D.; Kuperman, Rachel A.; Bebin, E. Martina; Korf, Bruce R.; Flamini, J. Robert; Kohrman, Michael H.; Sparagana, Steven P.; Wu, Joyce Y.; Brechenmacher, Thomas; Stein, Karen; Berkowitz, Noah; Bissler, John J.; Franz, David N.

    2014-01-01

    Background Tuberous sclerosis complex (TSC) is characterized by benign tumours in multiple organs, including the brain, kidneys, skin, lungs and heart. Our objective was to evaluate everolimus, an mTOR inhibitor, in the treatment of angiomyolipoma in patients with subependymal giant cell astrocytoma (SEGA) associated with TSC. Methods EXamining everolimus In a Study of Tuberous Sclerosis Complex-1 (NCT00789828), a prospective, double-blind, randomized, placebo-controlled, Phase 3 study, examined everolimus in treating SEGA associated with TSC. Patients with serial SEGA growth from pre-baseline to baseline scans were randomly assigned (2:1) to receive 4.5 mg/m2/day everolimus (target blood trough: 5–15 ng/mL; n = 78) or placebo (n = 39). Angiomyolipoma response rates were analysed in patients (n = 44) with target baseline angiomyolipoma lesions (≥1 angiomyolipoma; longest diameter ≥1.0 cm). An angiomyolipoma response rate, defined as the proportion of patients with confirmed angiomyolipoma response, was assessed by kidney CT or MRI screening at baseline, at 12, 24 and 48 weeks and annually. Results Angiomyolipoma response rates were 53.3% (16/30) and 0% (0/14) for everolimus- and placebo-treated patients, respectively. Angiomyolipoma reductions ≥50% in the sum of volumes of all target lesions were seen only in everolimus-treated patients (56.5, 78.3 and 80.0%) compared with placebo-treated patients (0% at each time point) at Weeks 12, 24 and 48, respectively. Greater percentages of everolimus-treated patients had angiomyolipoma reductions ≥30% at these same time points (82.6, 100 and 100% versus 8.3, 18.2 and 16.7% for everolimus versus placebo, respectively). Conclusions Everolimus showed efficacy in reducing angiomyolipoma lesion volume in patients with SEGA associated with TSC. The trial is registered with ClinicalTrials.gov, number NCT00789828; http://clinicaltrials.gov/ct2/show/NCT00789828?term=EXIST-1&rank=1. PMID:24729041

  2. Palmar-plantar erythrodysesthesia: An uncommon adverse effect of everolimus

    PubMed Central

    Arora, Shalabh; Akhil, Rajendra; Chacko, Raju Titus; George, Renu

    2016-01-01

    Mammalian target of rapamycin inhibitor everolimus is a novel agent used in endocrine therapy resistant hormone receptor positive metastatic breast cancer. Its use has been associated with clinically significant improvement in the otherwise dismal outcomes of this subset of patients. Rash is a common adverse effect associated with everolimus. However, Hand-foot syndrome is an uncommon toxicity with the use of this drug. We report a case of Grade 3 hand-foot syndrome following institution of everolimus therapy and describe its successful management. PMID:27168711

  3. A Small Molecule Screen Exposes mTOR Signaling Pathway Involvement in Radiation-Induced Apoptosis.

    PubMed

    Sharlow, Elizabeth R; Leimgruber, Stephanie; Lira, Ana; McConnell, Michael J; Norambuena, Andrés; Bloom, George S; Epperly, Michael W; Greenberger, Joel S; Lazo, John S

    2016-05-20

    Individuals are at risk of exposure to acute ionizing radiation (IR) from a nuclear accident or terrorism, but we lack effective therapies to mitigate the lethal IR effects. In the current study, we exploited an optimized, cell-based, high throughput screening assay to interrogate a small molecule library comprising 3437 known pharmacologically active compounds for mitigation against IR-induced apoptosis. Thirty-three library compounds significantly reduced apoptosis when administered 1 h after 4 Gy IR. Two- or three-dimensional computational structural analyses of the compounds indicated only one or two chemical clusters with most of the compounds being unique structures. The mechanistic target of rapamycin complex 1 (mTORC1) inhibitor, rapamycin, was the most potent compound, and it mitigated apoptosis by 50% at 200 ± 50 pM. Other mTOR inhibitors, namely everolimus, AZD8055, and torin 1, also suppressed apoptosis, providing additional pharmacological evidence for mTOR pathway involvement in regulating cell death after IR. Everolimus and torin 1 treatment after IR decreased the S phase population and enforced both G1 and G2 phase arrest. This prorogation of cell cycle progression was accompanied by decreased IR-induced DNA damage measured by γH2AX phosphorylation at Ser139. RNA interference-mediated knockdown of the respective mTORC1 and mTORC2 subunits, Raptor or Rictor, also mitigated IR-induced apoptosis. Collectively, this study suggests a central role for the mTOR signaling in the cytotoxic response to IR and offers a useful platform to probe for additional agents. PMID:26938669

  4. The Changes of Lipid Metabolism in Advanced Renal Cell Carcinoma Patients Treated with Everolimus: A New Pharmacodynamic Marker?

    PubMed Central

    Pantano, Francesco; Santoni, Matteo; Procopio, Giuseppe; Rizzo, Mimma; Iacovelli, Roberto; Porta, Camillo; Conti, Alessandro; Lugini, Antonio; Milella, Michele; Galli, Luca; Ortega, Cinzia; Guida, Francesco Maria; Silletta, Marianna; Schinzari, Giovanni; Verzoni, Elena; Modica, Daniela; Crucitti, Pierfilippo; Rauco, Annamaria; Felici, Alessandra; Ballatore, Valentina; Cascinu, Stefano; Tonini, Giuseppe; Carteni, Giacomo; Russo, Antonio; Santini, Daniele

    2015-01-01

    Background Everolimus is a mammalian target of rapamycin (mTOR) inhibitor approved for the treatment of metastatic renal cell carcinoma (mRCC). We aimed to assess the association between the baseline values and treatmentrelated modifications of total serum cholesterol (C), triglycerides (T), body mass index (BMI), fasting blood glucose level (FBG) and blood pressure (BP) levels and the outcome of patients treated with everolimus for mRCC. Methods 177 patients were included in this retrospective analysis. Time to progression (TTP), clinical benefit (CB) and overall survival (OS) were evaluated. Results Basal BMI was significantly higher in patients who experienced a CB (p=0,0145). C,T and C+T raises were significantly associated with baseline BMI (p=0.0412, 0.0283 and 0.0001). Median TTP was significantly longer in patients with T raise compared to patients without T (10 vs 6, p=0.030), C (8 vs 5, p=0.042) and C+T raise (10.9 vs 5.0, p=0.003). At the multivariate analysis, only C+T increase was associated with improved TTP (p=0.005). T raise (21.0 vs 14.0, p=0.002) and C+T increase (21.0 vs 14.0, p=0.006) were correlated with improved OS but were not significant at multivariate analysis. Conclusion C+T raise is an early predictor for everolimus efficacy for patients with mRCC. PMID:25885920

  5. Cabozantinib versus everolimus in advanced renal cell carcinoma

    PubMed Central

    Choueiri, Toni K.; Escudier, Bernard; Powles, Thomas; Mainwaring, Paul; Rini, Brian I.; Donskov, Frede; Hammers, Hans; Hutson, Thomas E.; Lee, Jae-Lyun; Peltola, Katriina; Roth, Bruce J.; Bjarnason, Georg A.; Géczi, Lajos; Keam, Bhumsuk; Moroto, Pablo; Heng, Daniel Y. C.; Schmidinger, Manuela; Kantoff, Philip W.; Borgman, Anne; Hessel, Colin; Scheffold, Christian; Schwab, Gisela M.; Tannir, Nizar M.; Motzer, Robert J.

    2016-01-01

    Background Cabozantinib is an oral small molecule tyrosine kinase inhibitor that targets vascular endothelial growth factor receptor (VEGFR) as well as MET and AXL; each has been implicated in metastatic renal cell carcinoma (RCC) pathobiology or development of resistance to antiangiogenic drugs. This randomized open-label phase 3 trial evaluated the efficacy of cabozantinib compared to everolimus in RCC patients who progressed after VEGFR-targeted therapy. Methods The trial randomized 658 patients to receive cabozantinib at a dose of 60 mg daily, or everolimus at a dose of 10 mg daily. The primary endpoint was progression-free survival. Secondary efficacy endpoints were overall survival and objective response rate. Results Median progression-free survival was 7.4 months with cabozantinib and 3.8 months with everolimus. The risk of progression or death was 42% lower with cabozantinib compared to everolimus (hazard ratio, 0.58; 95% confidence interval [CI] 0.45 to 0.75; P < 0.001). Objective response rates were 21% with cabozantinib and 5% with everolimus (P < 0.001). A planned interim analysis showed that overall survival was improved with cabozantinib (hazard ratio, 0.67; 95% CI, 0.51 to 0.89; P = 0.005) but did not cross the significance boundary. Adverse events (grade 3 or 4, regardless of causality) were reported in 74% of cabozantinib patients and 65% of everolimus patients. Discontinuation of study treatment for adverse events occurred in 9.1% of cabozantinib patients and 10% of everolimus patients. Conclusions Cabozantinib improved progression-free survival compared to everolimus in RCC patients who progressed after VEGFR-targeted therapy. PMID:26406150

  6. mTOR inhibitors counteract tamoxifen-induced activation of breast cancer stem cells.

    PubMed

    Karthik, Govindasamy-Muralidharan; Ma, Ran; Lövrot, John; Kis, Lorand Levente; Lindh, Claes; Blomquist, Lennart; Fredriksson, Irma; Bergh, Jonas; Hartman, Johan

    2015-10-10

    Breast cancer cells with stem cell characteristics (CSC) are a distinct cell population with phenotypic similarities to mammary stem cells. CSCs are important drivers of tumorigenesis and the metastatic process. Tamoxifen is the most widely used hormonal therapy for estrogen receptor (ER) positive cancers. In our study, tamoxifen was effective in reducing proliferation of ER + adherent cancer cells, but not their CSC population. We isolated, expanded and incubated CSC from seven breast cancers with or without tamoxifen. By genome-wide transcriptional analysis we identified tamoxifen-induced transcriptional pathways associated with ribosomal biogenesis and mRNA translation, both regulated by the mTOR-pathway. We observed induction of the key mTOR downstream targets S6K1, S6RP and 4E-BP1 in-patient derived CSCs by tamoxifen on protein level. Using the mTOR inhibitors rapamycin, everolimus and PF-04691502 (a dual PI3K/mTOR inhibitor) and in combination with tamoxifen, significant reduction in mammosphere formation was observed. Hence, we suggest that the CSC population play a significant role during endocrine resistance through activity of the mTOR pathway. In addition, tamoxifen further stimulates the mTOR-pathway but can be antagonized using mTOR-inhibitors. PMID:26208432

  7. The combination of IκB kinase β inhibitor and everolimus modulates expression of interleukin‐10 in human T‐cell lymphotropic virus type‐1‐infected T cells

    PubMed Central

    Nishioka, Chie; Ikezoe, Takayuki; Yang, Jing; Udaka, Keiko; Yokoyama, Akihito

    2013-01-01

    Summary Adult T‐cell leukaemia‐lymphoma (ATLL) is an aggressive malignancy of CD4+ CD25+ T lymphocytes, characterized by a severely compromised immunosystem, in which the human T‐cell lymphotropic virus type 1 (HTLV‐1) has been recognized as the aetiological agent. This study found that an IκB kinase β (IKKβ) inhibitor Bay11‐7082 inactivated mammalian target of rapamycin (mTOR), signal transducer and activator of transcription 3 and transcription factor nuclear factor‐κB in HTLV‐1‐infected T cells; this was significantly enhanced in the presence of the mTOR inhibitor everolimus. In addition, Bay11‐7082 decreased production of the immunosuppressive cytokine interleukin‐10 (IL‐10), which was further down‐regulated when Bay11‐7082 was combined with evelolimus in HTLV‐1‐infected T and ATLL cells isolated from patients. Interleukin‐10 is known to inhibit maturation and the antigen‐presenting function of dendritic cells (DCs). The culture media of HTLV‐1‐infected MT‐1 cells, which contained a large amout of IL‐10, hampered tumour necrosis factor‐α‐induced maturation of DCs isolated from healthy volunteers. Culture supernatant of MT‐1 cells treated with a combination of Bay11‐7082 and everolimus augmented maturation of DCs in association with a decrease in production of IL‐10 and enhanced the allostimulatory function of DCs. Similarly, when DCs isolated from patients with ATLL were treated with the combination of Bay11‐7082 and everolimus, they were fully matured and their capability to stimulate proliferation of lymphocytes was augmented. Taken together, the combination of Bay11‐7082 and everolimus might exhibit immunostimulatory properties in HTLV‐1‐infected T and ATLL cells isolated from patients, and this combination may be potentially therapeutic to regain the compromised immunosystem in ATLL patients. PMID:23278479

  8. Sirolimus and Everolimus Pathway: Reviewing Candidate Genes Influencing Their Intracellular Effects.

    PubMed

    Granata, Simona; Dalla Gassa, Alessandra; Carraro, Amedeo; Brunelli, Matteo; Stallone, Giovanni; Lupo, Antonio; Zaza, Gianluigi

    2016-01-01

    Sirolimus (SRL) and everolimus (EVR) are mammalian targets of rapamycin inhibitors (mTOR-I) largely employed in renal transplantation and oncology as immunosuppressive/antiproliferative agents. SRL was the first mTOR-I produced by the bacterium Streptomyces hygroscopicus and approved for several medical purposes. EVR, derived from SRL, contains a 2-hydroxy-ethyl chain in the 40th position that makes the drug more hydrophilic than SRL and increases oral bioavailability. Their main mechanism of action is the inhibition of the mTOR complex 1 and the regulation of factors involved in a several crucial cellular functions including: protein synthesis, regulation of angiogenesis, lipid biosynthesis, mitochondrial biogenesis and function, cell cycle, and autophagy. Most of the proteins/enzymes belonging to the aforementioned biological processes are encoded by numerous and tightly regulated genes. However, at the moment, the polygenic influence on SRL/EVR cellular effects is still not completely defined, and its comprehension represents a key challenge for researchers. Therefore, to obtain a complete picture of the cellular network connected to SRL/EVR, we decided to review major evidences available in the literature regarding the genetic influence on mTOR-I biology/pharmacology and to build, for the first time, a useful and specific "SRL/EVR genes-focused pathway", possibly employable as a starting point for future in-depth research projects. PMID:27187382

  9. Ganciclovir-Resistant Cytomegalovirus Infection in a Kidney Transplant Recipient Successfully Treated with Foscarnet and Everolimus.

    PubMed

    Menghi, Viola; Comai, Giorgia; Baraldi, Olga; Liviano D'Arcangelo, Giovanni; Lazzarotto, Tiziana; La Manna, Gaetano

    2016-01-01

    Cytomegalovirus (CMV) infection remains a major cause of morbidity, graft failure, and death in kidney transplant recipients. We describe a case of a 53-year-old CMV-seronegative man who underwent renal transplant from a CMV-positive donor and who developed ganciclovir- (GCV-) resistant CMV infection. Foscarnet was started while immunosuppressive therapy was modified with the introduction of everolimus minimizing tacrolimus dosage. Only two weeks after the start of this treatment regimen was the patient's viral load negative. At two-year follow-up the patient has no clinical or laboratory signs of CMV infection and a good and stable renal function or graft survival. In our case, administration of an mTOR inhibitor combined with foscarnet led to rapid and persistent viral clearance without compromising short- and medium-term graft function. This combination therapy supports the need for the kidney transplant community to individualize a target therapy for each type of GCV-resistant CMV infection. PMID:26942027

  10. Ganciclovir-Resistant Cytomegalovirus Infection in a Kidney Transplant Recipient Successfully Treated with Foscarnet and Everolimus

    PubMed Central

    Menghi, Viola; Comai, Giorgia; Baraldi, Olga; Liviano D'Arcangelo, Giovanni; Lazzarotto, Tiziana; La Manna, Gaetano

    2016-01-01

    Cytomegalovirus (CMV) infection remains a major cause of morbidity, graft failure, and death in kidney transplant recipients. We describe a case of a 53-year-old CMV-seronegative man who underwent renal transplant from a CMV-positive donor and who developed ganciclovir- (GCV-) resistant CMV infection. Foscarnet was started while immunosuppressive therapy was modified with the introduction of everolimus minimizing tacrolimus dosage. Only two weeks after the start of this treatment regimen was the patient's viral load negative. At two-year follow-up the patient has no clinical or laboratory signs of CMV infection and a good and stable renal function or graft survival. In our case, administration of an mTOR inhibitor combined with foscarnet led to rapid and persistent viral clearance without compromising short- and medium-term graft function. This combination therapy supports the need for the kidney transplant community to individualize a target therapy for each type of GCV-resistant CMV infection. PMID:26942027

  11. Sirolimus and Everolimus Pathway: Reviewing Candidate Genes Influencing Their Intracellular Effects

    PubMed Central

    Granata, Simona; Dalla Gassa, Alessandra; Carraro, Amedeo; Brunelli, Matteo; Stallone, Giovanni; Lupo, Antonio; Zaza, Gianluigi

    2016-01-01

    Sirolimus (SRL) and everolimus (EVR) are mammalian targets of rapamycin inhibitors (mTOR-I) largely employed in renal transplantation and oncology as immunosuppressive/antiproliferative agents. SRL was the first mTOR-I produced by the bacterium Streptomyces hygroscopicus and approved for several medical purposes. EVR, derived from SRL, contains a 2-hydroxy-ethyl chain in the 40th position that makes the drug more hydrophilic than SRL and increases oral bioavailability. Their main mechanism of action is the inhibition of the mTOR complex 1 and the regulation of factors involved in a several crucial cellular functions including: protein synthesis, regulation of angiogenesis, lipid biosynthesis, mitochondrial biogenesis and function, cell cycle, and autophagy. Most of the proteins/enzymes belonging to the aforementioned biological processes are encoded by numerous and tightly regulated genes. However, at the moment, the polygenic influence on SRL/EVR cellular effects is still not completely defined, and its comprehension represents a key challenge for researchers. Therefore, to obtain a complete picture of the cellular network connected to SRL/EVR, we decided to review major evidences available in the literature regarding the genetic influence on mTOR-I biology/pharmacology and to build, for the first time, a useful and specific “SRL/EVR genes-focused pathway”, possibly employable as a starting point for future in-depth research projects. PMID:27187382

  12. Combination treatment with hypoxia-activated prodrug evofosfamide (TH-302) and mTOR inhibitors results in enhanced antitumor efficacy in preclinical renal cell carcinoma models

    PubMed Central

    Sun, Jessica D; Ahluwalia, Dharmendra; Liu, Qian; Li, Wenwu; Wang, Yan; Meng, Fanying; Bhupathi, Deepthi; Matteucci, Mark D; Hart, Charles P

    2015-01-01

    Tumors often consist of hypoxic regions which are resistant to chemo- and radiotherapy. Evofosfamide (also known as TH-302), a 2-nitroimidazole triggered hypoxia-activated prodrug, preferentially releases the DNA cross-linker bromo-isophosphoramide mustard in hypoxic cells. The intracellular kinase mTOR plays a key role in multiple pathways which are important in cancer progression. Here we investigated the enhanced efficacy profile and possible mechanisms of evofosfamide in combination with mTOR inhibitor (mTORi) everolimus or temsirolimus in renal cell carcinoma (RCC) xenograft models. The antitumor activities of the mTORi everolimus or temsirolimus alone, evofosfamide alone, or the combination were investigated in the 786-O and Caki-1 RCC cells in vitro and in vivo xenograft models. Two schedules were tested in which evofosfamide was started on the same day as the mTORi or 1 week after. Combination mechanisms were investigated by measuring a panel of pharmacodynamic biomarkers by immunohistochemistry. Antitumor efficacy in both RCC xenograft models was enhanced by the combination of evofosfamide and mTORi. Evofosfamide reduced the increased hypoxia induced by mTORi. Combination treatment induced increased DNA damage, decreased cell proliferation, and decreased survivin. Addition of mTORi did not change evofosfamide-mediated cytotoxicity in 786-O or Caki-1 cells in vitro which might suggest cell non-autonomous effects, specifically increased tumor hypoxia, are important for the in vivo combination activity. Taken together, evofosfamide potentiates the antitumor efficacy of mTOR inhibitors and inhibits the increased tumor hypoxia caused by mTOR inhibition. These studies provide a translational rationale for combining evofosfamide with mTOR inhibitors in clinical studies. PMID:26328245

  13. PTEN Loss Does Not Predict for Response to RAD001 (Everolimus) in a Glioblastoma Orthotopic Xenograft Test Panel

    PubMed Central

    Yang, Lin; Clarke, Michelle J.; Carlson, Brett L.; Mladek, Ann C.; Schroeder, Mark A.; Decker, Paul; Wu, Wenting; Kitange, Gaspar J.; Grogan, Patrick T.; Goble, Jennie M.; Uhm, Joon; Galanis, Evanthia; Giannini, Caterina; Lane, Heidi A.; James, C. David; Sarkaria, Jann N.

    2014-01-01

    Purpose Hyperactivation of the phosphatidylinositol 3-kinase/Akt signaling through disruption of PTEN function is common in glioblastoma multiforme, and these genetic changes are predicted to enhance sensitivity to mammalian target of rapamycin (mTOR) inhibitors such as RAD001 (everolimus). Experimental Design To test whether PTEN loss could be used as a predictive marker for mTOR inhibitor sensitivity, the response of 17 serially transplantable glioblastoma multiforme xenografts was evaluated in an orthotopic therapy evaluation model. Of these 17 xenograft lines, 7 have either genomic deletion or mutation of PTEN. Results Consistent with activation of Akt signaling, there was a good correlation between loss of PTEN function and elevated levels of Akt phosphorylation. However, of the 7 lines with disrupted PTEN function, only 1 tumor line (GBM10) was significantly sensitive to RAD001 therapy (25% prolongation in median survival), whereas1 of 10 xenograft lines with wild-type PTEN was significantly sensitive to RAD001 (GS22; 34% prolongation in survival). Relative to placebo, 5 days of RAD001 treatment was associated with a marked 66% reduction in the MIB1 proliferation index in the sensitive GBM10 line (deleted PTEN) compared with a 25% and 7% reduction in MIB1 labeling index in the insensitive GBM14 (mutant PTEN) and GBM15 (wild-type PTEN) lines, respectively. Consistent with a cytostatic antitumor effect, bioluminescent imaging of luciferase-transduced intracranial GBM10 xenografts showed slowed tumor growth without significant tumor regression during RAD001 therapy. Conclusion These data suggest that loss of PTEN function is insufficient to adequately predict responsiveness to mTOR inhibitors in glioblastoma multiforme. PMID:18559622

  14. Novel nervous and multi-system regenerative therapeutic strategies for diabetes mellitus with mTOR

    PubMed Central

    Maiese, Kenneth

    2016-01-01

    Throughout the globe, diabetes mellitus (DM) is increasing in incidence with limited therapies presently available to prevent or resolve the significant complications of this disorder. DM impacts multiple organs and affects all components of the central and peripheral nervous systems that can range from dementia to diabetic neuropathy. The mechanistic target of rapamycin (mTOR) is a promising agent for the development of novel regenerative strategies for the treatment of DM. mTOR and its related signaling pathways impact multiple metabolic parameters that include cellular metabolic homeostasis, insulin resistance, insulin secretion, stem cell proliferation and differentiation, pancreatic β-cell function, and programmed cell death with apoptosis and autophagy. mTOR is central element for the protein complexes mTOR Complex 1 (mTORC1) and mTOR Complex 2 (mTORC2) and is a critical component for a number of signaling pathways that involve phosphoinositide 3-kinase (PI 3-K), protein kinase B (Akt), AMP activated protein kinase (AMPK), silent mating type information regulation 2 homolog 1 (Saccharomyces cerevisiae) (SIRT1), Wnt1 inducible signaling pathway protein 1 (WISP1), and growth factors. As a result, mTOR represents an exciting target to offer new clinical avenues for the treatment of DM and the complications of this disease. Future studies directed to elucidate the delicate balance mTOR holds over cellular metabolism and the impact of its broad signaling pathways should foster the translation of these targets into effective clinical regimens for DM. PMID:27127460

  15. Novel nervous and multi-system regenerative therapeutic strategies for diabetes mellitus with mTOR.

    PubMed

    Maiese, Kenneth

    2016-03-01

    Throughout the globe, diabetes mellitus (DM) is increasing in incidence with limited therapies presently available to prevent or resolve the significant complications of this disorder. DM impacts multiple organs and affects all components of the central and peripheral nervous systems that can range from dementia to diabetic neuropathy. The mechanistic target of rapamycin (mTOR) is a promising agent for the development of novel regenerative strategies for the treatment of DM. mTOR and its related signaling pathways impact multiple metabolic parameters that include cellular metabolic homeostasis, insulin resistance, insulin secretion, stem cell proliferation and differentiation, pancreatic β-cell function, and programmed cell death with apoptosis and autophagy. mTOR is central element for the protein complexes mTOR Complex 1 (mTORC1) and mTOR Complex 2 (mTORC2) and is a critical component for a number of signaling pathways that involve phosphoinositide 3-kinase (PI 3-K), protein kinase B (Akt), AMP activated protein kinase (AMPK), silent mating type information regulation 2 homolog 1 (Saccharomyces cerevisiae) (SIRT1), Wnt1 inducible signaling pathway protein 1 (WISP1), and growth factors. As a result, mTOR represents an exciting target to offer new clinical avenues for the treatment of DM and the complications of this disease. Future studies directed to elucidate the delicate balance mTOR holds over cellular metabolism and the impact of its broad signaling pathways should foster the translation of these targets into effective clinical regimens for DM. PMID:27127460

  16. Early definite stent thrombosis with everolimus-eluting stents

    PubMed Central

    Naito, Ryo; Miyauchi, Katsumi; Konishi, Hirokazu; Tsuboi, Shuta; Okazaki, Shinya; Daida, Hiroyuki

    2015-01-01

    Key Clinical Message Stent thrombosis (ST) is a serious complication of percutaneous coronary intervention. Several factors are associated with ST, and combination of these factors increase the risk, even in everolimus-eluting stents, which have low risk of ST. We experienced a case of ST caused by limited coronary flow and resistance to antiplatelet agent. PMID:26509023

  17. Coronary vasomotion dysfunction after everolimus-eluting stent implantation.

    PubMed

    Giudice, Pietro; Attisano, Tiziana; Di Maio, Marco; Bellino, Elisabetta M; Polito, Maria V; Baldi, Cesare; Vigorito, Francesco; Di Muro, Michele R; Tomasello, Salvatore D; Galassi, Alfredo R; Piscione, Federico

    2014-12-01

    First generation drug-eluting stent can cause a paradoxical "in-segment" coronary vasoconstriction. This phenomenon was seen with sirolimus, paclitaxel, and, more recently, also with zotarolimus-eluting stent. For the first time, we describe a case of coronary-induced vasoconstriction by everolimus-eluting stents (EES). PMID:25598992

  18. mTOR inhibitors in cancer therapy

    PubMed Central

    Xie, Jianling; Wang, Xuemin; Proud, Christopher G.

    2016-01-01

    The mammalian target of rapamycin, mTOR, plays key roles in cell growth and proliferation, acting at the catalytic subunit of two protein kinase complexes: mTOR complexes 1 and 2 (mTORC1/2). mTORC1 signaling is switched on by several oncogenic signaling pathways and is accordingly hyperactive in the majority of cancers. Inhibiting mTORC1 signaling has therefore attracted great attention as an anti-cancer therapy. However, progress in using inhibitors of mTOR signaling as therapeutic agents in oncology has been limited by a number of factors, including the fact that the classic mTOR inhibitor, rapamycin, inhibits only some of the effects of mTOR; the existence of several feedback loops; and the crucial importance of mTOR in normal physiology.

  19. mTOR, linking metabolism and immunity

    PubMed Central

    Xu, Xiaojin; Ye, Lilin; Araki, Koichi; Ahmed, Rafi

    2013-01-01

    mTOR is an evolutionarily conserved serine/threonine kinase that plays a critical role in cell growth and metabolism by sensing different environmental cues. There is a growing appreciation of mTOR in immunology for its role in integrating diverse signals from the immune microenvironment and coordinating the functions of immune cells and their metabolism. In CD8 T cells, mTOR has shown to influence cellular commitment to effector versus memory programming; in CD4 T cells, mTOR integrates environmental cues that instruct effector cell differentiation. In this review, we summarize and discuss recent advances in the field, with a focus on the mechanisms through which mTOR regulates cellular and humoral immunity. Further understanding will enable the manipulation of mTOR signaling to direct the biological functions of immune cells, which holds great potential for improving immune therapies and vaccination against infections and cancer. PMID:23352227

  20. Multicenter phase II study of everolimus in patients with metastatic or recurrent bone and soft-tissue sarcomas after failure of anthracycline and ifosfamide.

    PubMed

    Yoo, Changhoon; Lee, Jeeyun; Rha, Sun Young; Park, Kyong Hwa; Kim, Tae Min; Kim, Yu Jung; Lee, Hyo Jin; Lee, Kyung Hee; Ahn, Jin-Hee

    2013-12-01

    This multicenter, phase II trial evaluated the efficacy and safety of everolimus, an mTOR inhibitor, in patients with metastatic or recurrent bone and soft-tissue sarcoma after the failure of anthracycline- and ifosfamide-containing regimens. Everolimus was administered orally as 10 mg once daily. The primary endpoint was the progression-free rate (PFR) at 16 weeks, assessed by computed tomography scan according to RECIST v1.0. Between July 2010 and May 2011, 41 patients were enrolled in this study. Among them, 83% received two or more regimens of chemotherapy prior to study entry. In 38 patients who the primary endpoint was evaluable, 11 patients reached 16 weeks progression-free (one with partial response and 10 with stable disease), indicating a PFR at 16 weeks of 27% (95% confidence interval [CI], 16-42%). The PFR at 16 weeks was highest in patients with angiosarcoma (2 of 3, 67%). With a median follow-up of 10.9 months (range, 2.3-23.9 months) in living patients, the median progression-free survival was 1.9 months (95% CI, 1.3-2.4 months) and the median overall survival was 5.8 months (95% CI, 3.6-8.0 months). Most adverse events were generally mild and tolerable. Grade 3/4 toxicities included hyperglycemia (15%), stomatitis (7%), pain (5%), and asthenia (5%). Everolimus shows modest antitumor activity with manageable toxicities in heavily pretreated patients with bone and soft-tissue sarcoma. PMID:24037083

  1. Phase II Study of Temozolomide (TMZ) and Everolimus (RAD001) Therapy for Metastatic Melanoma

    PubMed Central

    Dronca, Roxana S.; Allred, Jacob B.; Perez, Domingo G.; Nevala, Wendy K.; Lieser, Elizabeth A.T.; Thompson, Michael; Maples, William J.; Creagan, Edward T.; Pockaj, Barbara A.; Kaur, Judith S.; Moore, Timothy D.; Marchello, Benjamin T.; Markovic, Svetomir N.

    2014-01-01

    Objective Mammalian target of rapamycin (mTOR) pathway is activated in malignant melanoma and in situ lesions as opposed to benign nevi. Inhibition of PI3K-Akt-mTOR signaling is implicated in sensitization of melanoma cells to alkylating agents [temozolomide (TMZ)] and inhibition of tumor angiogenesis. Methods We conducted a single-arm phase II multi-institution cooperative group study to assess the antitumor activity and safety profile of the combination of TMZ and the rapamycin derivative everolimus in patients with metastatic unresectable malignant melanoma. Patients received 10 mg/d of RAD001 for 5 of 7 days (ie, 50 mg/ wk) and 200 mg/m2/d of TMZ for 5 days each cycle. Results Of the first 39 eligible patients, 17 were PFS-9 successes, for a predetermined threshold of 18/39 patients for a positive trial. Overall, 21 of 48 patients were progression free at 9 weeks, for an event-free survival rate of 44% (95% confidence interval, 29%–59%). The median progression-free survival was 2.4 months and the median overall survival was 8.6 months. Four patients achieved a partial response; the median duration of response was 15.1 months. No complete remissions were observed. Treatment was in general well tolerated with only 1 patient discontinuing therapy due to toxicity (hyperlipidemia). Conclusions The combination of TMZ and RAD001 was well tolerated but failed to meet/exceed our study threshold for promising clinical activity in patients with metastatic melanoma. PMID:23357973

  2. mTOR signaling in tumorigenesis

    PubMed Central

    Xu, Kai; Liu, Pengda; Wei, Wenyi

    2014-01-01

    mTOR (the mechanistic target of rapamycin) is an atypical serine/threonine kinase involved in regulating major cellular functions including growth and proliferation. Deregulations of the mTOR signaling pathway is one of the most commonly observed pathological alterations in human cancers. To this end, oncogenic activation of the mTOR signaling pathway contributes to cancer cell growth, proliferation and survival, highlighting the potential for targeting the oncogenic mTOR pathway members as an effective anti-cancer strategy. In order to do so, a thorough understanding of the physiological roles of key mTOR signaling pathway components and upstream regulators would guide future targeted therapies. Thus, in this review, we summarize available genetic mouse models for mTORC1 and mTORC2 components, as well as characterized mTOR upstream regulators and downstream targets, and assign a potential oncogenic or tumor suppressive role for each evaluated molecule. Together, our work will not only facilitate the current understanding of mTOR biology and possible future research directions, but more importantly, provide a molecular basis for targeted therapies aiming at key oncogenic members along the mTOR signaling pathway. PMID:25450580

  3. mTOR Inhibitors at a Glance

    PubMed Central

    Zheng, Yin; Jiang, Yu

    2016-01-01

    Mechanistic target of rapamycin (mTOR) is a conserved threonine and serine protein kinase that was identified more than two decades ago as the target of immunosuppressive drug rapamycin. Since then considerable amount of information has been learned about the function of this kinase. It is now well-established that mTOR plays a pivotal role in governing cell growth and proliferation, hence making mTOR a therapeutic target for disease conditions caused by deregulated cell proliferation, such as cancer. In the past decade, numerous mTOR inhibitors have been developed and many are currently in clinical trials for cancer treatment. This commentary is to provide a brief summary of these mTOR inhibitors. PMID:27134695

  4. Therapeutic Drug Monitoring of Everolimus: A Consensus Report.

    PubMed

    Shipkova, Maria; Hesselink, Dennis A; Holt, David W; Billaud, Eliane M; van Gelder, Teun; Kunicki, Paweł K; Brunet, Mercè; Budde, Klemens; Barten, Markus J; De Simone, Paolo; Wieland, Eberhard; López, Olga Millán; Masuda, Satohiro; Seger, Christoph; Picard, Nicolas; Oellerich, Michael; Langman, Loralie J; Wallemacq, Pierre; Morris, Raymond G; Thompson, Carol; Marquet, Pierre

    2016-04-01

    In 2014, the Immunosuppressive Drugs Scientific Committee of the International Association of Therapeutic Drug Monitoring and Clinical Toxicology called a meeting of international experts to provide recommendations to guide therapeutic drug monitoring (TDM) of everolimus (EVR) and its optimal use in clinical practice. EVR is a potent inhibitor of the mammalian target of rapamycin, approved for the prevention of organ transplant rejection and for the treatment of various types of cancer and tuberous sclerosis complex. EVR fulfills the prerequisites for TDM, having a narrow therapeutic range, high interindividual pharmacokinetic variability, and established drug exposure-response relationships. EVR trough concentrations (C0) demonstrate a good relationship with overall exposure, providing a simple and reliable index for TDM. Whole-blood samples should be used for measurement of EVR C0, and sampling times should be standardized to occur within 1 hour before the next dose, which should be taken at the same time everyday and preferably without food. In transplantation settings, EVR should be generally targeted to a C0 of 3-8 ng/mL when used in combination with other immunosuppressive drugs (calcineurin inhibitors and glucocorticoids); in calcineurin inhibitor-free regimens, the EVR target C0 range should be 6-10 ng/mL. Further studies are required to determine the clinical utility of TDM in nontransplantation settings. The choice of analytical method and differences between methods should be carefully considered when determining EVR concentrations, and when comparing and interpreting clinical trial outcomes. At present, a fully validated liquid chromatography tandem mass spectrometry assay is the preferred method for determination of EVR C0, with a lower limit of quantification close to 1 ng/mL. Use of certified commercially available whole-blood calibrators to avoid calibration bias and participation in external proficiency-testing programs to allow continuous cross

  5. Everolimus for Primary Intestinal Lymphangiectasia With Protein-Losing Enteropathy.

    PubMed

    Ozeki, Michio; Hori, Tomohiro; Kanda, Kaori; Kawamoto, Norio; Ibuka, Takashi; Miyazaki, Tatsuhiko; Fukao, Toshiyuki

    2016-03-01

    Primary intestinal lymphangiectasia (PIL), also known as Waldmann's disease, is an exudative enteropathy resulting from morphologic abnormalities in the intestinal lymphatics. In this article, we describe a 12-year-old boy with PIL that led to protein-losing enteropathy characterized by diarrhea, hypoalbuminemia associated with edema (serum albumin level: 1.0 g/dL), and hypogammaglobulinemia (serum IgG level: 144 mg/dL). Severe hypoalbuminemia, electrolyte abnormalities, and tetany persisted despite a low-fat diet and propranolol. Everolimus (1.6 mg/m(2)/day) was added to his treatment as an antiangiogenic agent. With everolimus treatment, the patient's diarrhea resolved and replacement therapy for hypoproteinemia was less frequent. Hematologic and scintigraphy findings also improved (serum albumin level: 2.5 g/dL). There were no adverse reactions during the 12-month follow-up. To the best of our knowledge, this is the first report of everolimus use in a patient with PIL. PMID:26908672

  6. Effects of mTOR inhibitors and cytoskeletal-directed agents alone and in combination against normal and neoplastic hematopoietic cells in vitro.

    PubMed

    Trendowski, Matthew; Christen, Timothy D; Andonova, Antoaneta A; Narampanawe, Berlini; Thibaud, Ashlee; Kusang, Tenzin; Fondy, Thomas P

    2015-12-01

    The mechanistic target of rapamycin (mTOR) controls cell growth and enlargement and has been found to be aberrant in a wide variety of malignancies. Although mTOR is already an attractive antineoplastic target, overexpression or aberrant expression of mTOR may also provide an opportunity to further increase the size differential between malignant and normal cells, providing an opportunity to amplify and exploit cell size differences between neoplastic cells and their normal counterparts using physiochemical treatment modalities. Therefore, this study sought to quantify the concentration response and time course effects of rapamycin on cell cycle entry, cell enlargement, and cell proliferation in U937 human monocytic leukemia and human hematopoietic stem cells (hHSCs). In addition, the effects of combination treatment with mTOR inhibitors (rapamycin, everolimus, and temsirolimus) and cytoskeletal-directed agents (cytochalasin B and vincristine) in leukemic cells (U937, THP1, K562, Molt-4, and L1210) were assessed for potential drug synergy. While both U937 cells and hHSCs exhibited a marked reduction in cell volume, U937 cells were able to proliferate in the presence of rapamycin ranging from 0.5 nM to 10 μM (10,000 nM), whereas hHSCs were able to proliferate only at lower concentrations, and were completely inhibited from proliferation by 8 nM rapamycin. These effects were observed with as little as 0.5 nM rapamycin, demonstrating the profound affinity the compound has for FK-binding protein 12 (FKBP12), which subsequently forms the FKBP12/rapamycin complex to inhibit mTOR. Rapamycin continued to exert effects on cell size and proliferation even at 10 μM, without producing marked cytotoxicity. Although cytochalasin B and vincristine were unable to substantially enlarge rapamycin-treated leukemia cells, it appears that rapamycin and its associated analogs everolimus and temsirolimus have notable synergistic potential with microfilament-disrupting cytochalasin B

  7. Co-administration strategy to enhance brain accumulation of vandetanib by modulating P-glycoprotein (P-gp/Abcb1) and breast cancer resistance protein (Bcrp1/Abcg2) mediated efflux with m-TOR inhibitors.

    PubMed

    Minocha, Mukul; Khurana, Varun; Qin, Bin; Pal, Dhananjay; Mitra, Ashim K

    2012-09-15

    The objectives of this study were (i) to characterize the interaction of vandetanib with P-glycoprotein (P-gp) and breast cancer resistance protein (Bcrp1) in vitro and in vivo (ii) to study the modulation of P-gp and BCRP mediated efflux of vandetanib with specific transport inhibitors and m-TOR inhibitors, everolimus and temsirolimus. Cellular accumulation and bi-directional transport studies in MDCKII cell monolayers were conducted to delineate the role of efflux transporters on disposition of vandetanib. Brain distribution studies were conducted in male FVB wild-type mice with vandetanib administered intravenously either alone or in the presence of specific inhibitors and m-TOR inhibitors. In vitro studies suggested that vandetanib is a high affinity substrate of Bcrp1 but is not transported by P-gp. Interestingly, in vivo brain distribution studies in FVB wild type mice indicated that vandetanib penetration into the brain is restricted by both Bcrp1 and P-gp mediated active efflux at the blood brain barrier (BBB). Co-administration of elacridar, a dual P-gp/BCRP inhibitor increased the brain to plasma concentration ratio of vandetanib upto 5 fold. Of the two m-TOR pathway inhibitors examined; everolimus showed potent effect on modulating vandetanib brain penetration whereas no significant affect on vandetanib brain uptake was observed following temsirolimus co-administration. This finding could be clinically relevant as everolimus can provide synergistic pharmacological effect in addition to primary role of vandetanib efflux modulation at BBB for the treatment of brain tumors. PMID:22633931

  8. Combined MTOR and autophagy inhibition

    PubMed Central

    Rangwala, Reshma; Chang, Yunyoung C; Hu, Janice; Algazy, Kenneth M; Evans, Tracey L; Fecher, Leslie A; Schuchter, Lynn M; Torigian, Drew A; Panosian, Jeffrey T; Troxel, Andrea B; Tan, Kay-See; Heitjan, Daniel F; DeMichele, Angela M; Vaughn, David J; Redlinger, Maryann; Alavi, Abass; Kaiser, Jonathon; Pontiggia, Laura; Davis, Lisa E; O’Dwyer, Peter J; Amaravadi, Ravi K

    2014-01-01

    The combination of temsirolimus (TEM), an MTOR inhibitor, and hydroxychloroquine (HCQ), an autophagy inhibitor, augments cell death in preclinical models. This phase 1 dose-escalation study evaluated the maximum tolerated dose (MTD), safety, preliminary activity, pharmacokinetics, and pharmacodynamics of HCQ in combination with TEM in cancer patients. In the dose escalation portion, 27 patients with advanced solid malignancies were enrolled, followed by a cohort expansion at the top dose level in 12 patients with metastatic melanoma. The combination of HCQ and TEM was well tolerated, and grade 3 or 4 toxicity was limited to anorexia (7%), fatigue (7%), and nausea (7%). An MTD was not reached for HCQ, and the recommended phase II dose was HCQ 600 mg twice daily in combination with TEM 25 mg weekly. Other common grade 1 or 2 toxicities included fatigue, anorexia, nausea, stomatitis, rash, and weight loss. No responses were observed; however, 14/21 (67%) patients in the dose escalation and 14/19 (74%) patients with melanoma achieved stable disease. The median progression-free survival in 13 melanoma patients treated with HCQ 1200mg/d in combination with TEM was 3.5 mo. Novel 18-fluorodeoxyglucose positron emission tomography (FDG-PET) measurements predicted clinical outcome and provided further evidence that the addition of HCQ to TEM produced metabolic stress on tumors in patients that experienced clinical benefit. Pharmacodynamic evidence of autophagy inhibition was evident in serial PBMC and tumor biopsies only in patients treated with 1200 mg daily HCQ. This study indicates that TEM and HCQ is safe and tolerable, modulates autophagy in patients, and has significant antitumor activity. Further studies combining MTOR and autophagy inhibitors in cancer patients are warranted. PMID:24991838

  9. Mammalian Target of Rapamycin (mTOR) Inhibition as a Potential Antiepileptogenic Therapy: From Tuberous Sclerosis to Common Acquired Epilepsies

    PubMed Central

    Wong, Michael

    2011-01-01

    SUMMARY Most current treatments for epilepsy are symptomatic therapies that suppress seizures but do not affect the underlying course or prognosis of epilepsy. The need for disease-modifying or “antiepileptogenic” treatments for epilepsy is widely recognized, but no such preventative therapies have yet been established for clinical use. A rational strategy for preventing epilepsy is to target primary signaling pathways that initially trigger the numerous downstream mechanisms mediating epileptogenesis. The mammalian target of rapamycin (mTOR) pathway represents a logical candidate, because mTOR regulates multiple cellular functions that may contribute to epileptogenesis, including protein synthesis, cell growth and proliferation, and synaptic plasticity. The importance of the mTOR pathway in epileptogenesis is best illustrated by Tuberous Sclerosis Complex (TSC), one of the most common genetic causes of epilepsy. In mouse models of TSC, mTOR inhibitors prevent the development of epilepsy and underlying brain abnormalities associated with epileptogenesis. Accumulating evidence suggests that mTOR also participates in epileptogenesis due to a variety of other causes, including focal cortical dysplasia and acquired brain injuries, such as in animal models following status epilepticus or traumatic brain injury. Thus, mTOR inhibition may represent a potential antiepileptogenic therapy for diverse types of epilepsy, including both genetic and acquired epilepsies. PMID:19817806

  10. Overcoming mTOR resistance mutations with a new-generation mTOR inhibitor.

    PubMed

    Rodrik-Outmezguine, Vanessa S; Okaniwa, Masanori; Yao, Zhan; Novotny, Chris J; McWhirter, Claire; Banaji, Arpitha; Won, Helen; Wong, Wai; Berger, Mike; de Stanchina, Elisa; Barratt, Derek G; Cosulich, Sabina; Klinowska, Teresa; Rosen, Neal; Shokat, Kevan M

    2016-06-01

    Precision medicines exert selective pressure on tumour cells that leads to the preferential growth of resistant subpopulations, necessitating the development of next-generation therapies to treat the evolving cancer. The PIK3CA-AKT-mTOR pathway is one of the most commonly activated pathways in human cancers, which has led to the development of small-molecule inhibitors that target various nodes in the pathway. Among these agents, first-generation mTOR inhibitors (rapalogs) have caused responses in 'N-of-1' cases, and second-generation mTOR kinase inhibitors (TORKi) are currently in clinical trials. Here we sought to delineate the likely resistance mechanisms to existing mTOR inhibitors in human cell lines, as a guide for next-generation therapies. The mechanism of resistance to the TORKi was unusual in that intrinsic kinase activity of mTOR was increased, rather than a direct active-site mutation interfering with drug binding. Indeed, identical drug-resistant mutations have been also identified in drug-naive patients, suggesting that tumours with activating MTOR mutations will be intrinsically resistant to second-generation mTOR inhibitors. We report the development of a new class of mTOR inhibitors that overcomes resistance to existing first- and second-generation inhibitors. The third-generation mTOR inhibitor exploits the unique juxtaposition of two drug-binding pockets to create a bivalent interaction that allows inhibition of these resistant mutants. PMID:27279227

  11. Effects of everolimus on a rat model of cerulein-induced experimental acute pancreatitis

    PubMed Central

    Özkardeş, Alper Bilal; Bozkurt, Birkan; Dumlu, Ersin Gürkan; Tokaç, Mehmet; Yazgan, Aylin Kılıç; Ergin, Merve; Erel, Özcan; Kılıç, Mehmet

    2015-01-01

    Objective: To analyze the biochemical and histopathological effects of everolimus in an experimental rat model of cerulein-induced acute pancreatitis. The aim of the present study was to determine the effects of everolimus on blood biochemical parameters and tissue histopathology in an experimental rat model of cerulein-induced acute pancreatitis. Material and Methods: In 30 Wistar albino rats (male; 240–260 g), acute pancreatitis was induced by an intraperitoneal injection of cerulein (50 μg/kg) administered twice in 2 h. They were equally divided into the following three groups: 0.9% isotonic solution (Group 1; control), everolimus once (Group 2), and everolimus twice (Group 3) by oral gavage after cerulein injection. Thirty hours after the induction of pancreatitis, blood samples were collected by direct intracardiac puncture, rats were sacrificed, and pancreatic tissue samples were obtained. Results: Biochemical analyses of the blood samples showed statistically significant difference in red blood cell count as well as hemoglobin, hematocrit, urea, and alanine transaminase levels among the study groups (p<0.05 in all). Everolimus proved to significantly increase red blood cell count in a dose-independent manner. Hemoglobin and hematocrit levels significantly increased only after treatment with one dose of everolimus. Urea level was significantly different between the Groups 2 and 3; however, no change was observed in both groups when compared with the control. Alanine transaminase level significantly decreased only after treatment with two doses of everolimus. Histopathological analyses revealed that everolimus significantly decreased inflammation and perivascular infiltrate in a dose-dependent manner (35% in Group 2, 75% in Group 3; p=0.048). Conclusion: Treatment with two doses of everolimus improved some biochemical and histopathological parameters of experimental rat models of cerulein-induced acute pancreatitis and implied the specific inhibition of

  12. Comparative Metabolomic Profiling of Hepatocellular Carcinoma Cells Treated with Sorafenib Monotherapy vs. Sorafenib-Everolimus Combination Therapy

    PubMed Central

    Zheng, Jian-feng; Lu, Juan; Wang, Xiao-zhong; Guo, Wu-hua; Zhang, Ji-xiang

    2015-01-01

    Background Sorafenib-everolimus combination therapy may be more effective than sorafenib monotherapy for hepatocellular carcinoma (HCC). To better understand this effect, we comparatively profiled the metabolite composition of HepG2 cells treated with sorafenib, everolimus, and sorafenib-everolimus combination therapy. Material/Methods A 2D HRMAS 1H-NMR metabolomic approach was applied to identify the key differential metabolites in 3 experimental groups: sorafenib (5 μM), everolimus (5 μM), and combination therapy (5 μM sorafenib +5 μM everolimus). MetaboAnalyst 3.0 was used to perform pathway analysis. Results All OPLS-DA models displayed good separation between experimental groups, high-quality goodness of fit (R2), and high-quality goodness of predication (Q2). Sorafenib and everolimus have differential effects with respect to amino acid, methane, pyruvate, pyrimidine, aminoacyl-tRNA biosynthesis, and glycerophospholipid metabolism. The addition of everolimus to sorafenib resulted in differential effects with respect to pyruvate, amino acid, methane, glyoxylate and dicarboxylate, glycolysis or gluconeogenesis, glycerophospholipid, and purine metabolism. Conclusions Sorafenib and everolimus have differential effects on HepG2 cells. Sorafenib preferentially affects glycerophospholipid and purine metabolism, while the addition of everolimus preferentially affects pyruvate, amino acid, and glucose metabolism. This phenomenon may explain (in part) the synergistic effects of sorafenib-everolimus combination therapy observed in vivo. PMID:26092946

  13. Dissociation of the Pharmacological Effects of THC by mTOR Blockade

    PubMed Central

    Puighermanal, Emma; Busquets-Garcia, Arnau; Gomis-González, Maria; Marsicano, Giovanni; Maldonado, Rafael; Ozaita, Andrés

    2013-01-01

    The potential therapeutic benefits of cannabinoid compounds have raised interest in understanding the molecular mechanisms that underlie cannabinoid-mediated effects. We previously showed that the acute amnesic-like effects of delta9-tetrahydrocannabinol (THC) were prevented by the subchronic inhibition of the mammalian target of rapamycin (mTOR) pathway. In the present study, we assess the relevance of the mTOR pathway in other acute and chronic pharmacological effects of THC. The rapamycin derivative temsirolimus, an inhibitor of the mTOR pathway approved by the Food and Drug Administration, prevents both the anxiogenic- and the amnesic-like effects produced by acute THC. In contrast, THC-induced anxiolysis, hypothermia, hypolocomotion, and antinociception are not sensitive to the mTOR inhibition. In addition, a clear tolerance to THC-induced anxiolysis, hypothermia, hypolocomotion, and antinociception was observed after chronic treatment, but not to its anxiogenic- and amnesic-like effects. Temsirolimus pre-treatment prevented the amnesic-like effects of chronic THC without affecting the downregulation of CB1 receptors (CB1R) induced by this chronic treatment. Instead, temsirolimus blockade after chronic THC cessation did not prevent the residual cognitive deficit produced by chronic THC. Using conditional knockout mice lacking CB1R in GABAergic or glutamatergic neurons, we found that GABAergic CB1Rs are mainly downregulated under chronic THC treatment conditions, and CB1–GABA–KO mice did not develop cognitive deficits after chronic THC exposure. Therefore, mTOR inhibition by temsirolimus allows the segregation of the potentially beneficial effects of cannabinoid agonists, such as the anxiolytic and antinociceptive effects, from the negative effects, such as anxiogenic- and amnesic-like responses. Altogether, these results provide new insights for targeting the endocannabinoid system in order to prevent possible side effects. PMID:23358238

  14. Decreased Lymphangiogenesis and Lymph Node Metastasis by mTOR Inhibition in Head and Neck Cancer

    PubMed Central

    Patel, Vyomesh; Marsh, Christina A.; Dorsam, Robert T.; Mikelis, Constantinos M.; Masedunskas, Andrius; Amornphimoltham, Panomwat; Nathan, Cherie Ann; Singh, Bhuvanesh; Weigert, Roberto; Molinolo, Alfredo A.; Gutkind, J. Silvio

    2012-01-01

    Despite our improved understanding of cancer, the 5-year survival rate for head and neck squamous cell carcinomas (HNSCC) patients remains relatively unchanged at 50% for the past three decades. HNSCC often metastasize to locoregional lymph nodes, and lymph node involvement represents one of the most important prognostic factors of poor clinical outcome. Among the multiple dysregulated molecular mechanism in HNSCC, emerging basic, preclinical, and clinical findings support the importance of the mTOR signaling route in HNSCC progression. Indeed, we observed here that the activation of mTOR is a widespread event in clinical specimens of HNSCC invading locoregional lymph nodes. We developed an orthotopic model of HNSCC consisting in the implantation of HNSCC cells into the tongues of immunocompromised mice. These orthotopic tumors spontaneously metastasize to the cervical lymph nodes, where the presence of HNSCC cells can be revealed by histological and immunohistochemical evaluation. Both primary and metastatic experimental HNSCC lesions exhibited elevated mTOR activity. The ability to monitor and quantitate lymph node invasion in this model system enabled us to explore whether the blockade of mTOR could impact on HNSCC metastasis. We found that inhibition of mTOR with rapamycin and the rapalog RAD001 diminished lymphangiogenesis in the primary tumors and prevented the dissemination of HNSCC cancer cells to the cervical lymph nodes, thereby prolonging animal survival. These findings may provide a rationale for the future clinical evaluation of mTOR inhibitors, including rapamycin and its analogs, as part of a molecular-targeted metastasis preventive strategy for the treatment of HNSCC patients. PMID:21975930

  15. Everolimus Treatment for an Early Infantile Subependymal Giant Cell Astrocytoma With Tuberous Sclerosis Complex.

    PubMed

    Fukumura, Shinobu; Watanabe, Toshihide; Takayama, Rumiko; Minagawa, Kimio; Tsutsumi, Hiroyuki

    2015-08-01

    Subependymal giant cell astrocytomas are benign tumors often observed with tuberous sclerosis complex. These tumors are rarely diagnosed during fetal life or early infancy. Until recently, the only available treatment has been surgical resection. Current clinical research has demonstrated that everolimus can induce these tumors' regression. We report a 19-month-old boy with tuberous sclerosis complex. At 2 months of age, he presented with congenital subependymal giant cell astrocytoma that was complicated by refractory epilepsy and severe mental retardation. Treatment with everolimus was started when he was 10 months old. Three months after initiating everolimus, the tumor was significantly reduced in size, and the reduction was subsequently maintained. His seizures decreased and he showed cognitive and developmental improvement. No severe adverse events have been observed to date. Everolimus has promise as an effective alternative to surgery for subependymal giant cell astrocytomas during early infancy. PMID:25143481

  16. Everolimus-induced Pneumonitis after Drug-eluting Stent Implantation: A Case Report

    SciTech Connect

    Sakamoto, Susumu Kikuchi, Naoshi; Ichikawa, Atsuo; Sano, Go; Satoh, Keita; Sugino, Keishi; Isobe, Kazutoshi; Takai, Yujiro; Shibuya, Kazutoshi; Homma, Sakae

    2013-08-01

    Despite the wide use of everolimus as an antineoplastic coating agent for coronary stents to reduce the rate of restenosis, little is known about the health hazards of everolimus-eluting stents (EES). We describe a case of pneumonitis that developed 2 months after EES implantation for angina. Lung pathology demonstrated an organizing pneumonia pattern that responded to corticosteroid therapy. Although the efficacy of EES for ischemic heart disease is well established, EES carries a risk of pneumonitis.

  17. Activation of Autophagy by Everolimus Confers Hepatoprotection Against Ischemia-Reperfusion Injury.

    PubMed

    Lee, S C; Kim, K H; Kim, O H; Lee, S K; Kim, S J

    2016-07-01

    As the criteria for liver donation have been extended to include marginal donors, liver grafts are becoming particularly vulnerable to hepatic ischemia-reperfusion injury (IRI). However, no specific measures have been validated to ameliorate hepatic IRI. In this article, we explored whether everolimus has protective effects against hepatic IRI in relation with autophagy. The effects of everolimus were investigated in both in vitro and in vivo hepatic IRI models. Mouse hepatocyte AML12 cells and BALB/c mice were utilized for the establishment of each model. In the IRI-induced AML12 cells, everolimus treatment increased the expressions of autophagic markers (microtubule-associated protein 1 light chain 3 and p62) and decreased pro-apoptotic proteins (cleaved caspase 3 and cleaved poly-ADP ribose polymerase). The blockage of autophagy, using either bafilomycin A1 or si-autophagy-related protein 5, abrogated these anti-apoptosis effects of everolimus. Subsequently, everolimus administration to the hepatic IRI-induced mice provided hepatoprotective effects in terms of (1) decreasing the expressions of pro-apoptotic proteins, (2) inhibiting the release of pro-inflammatory cytokines (IL-6 and tumor necrosis factor-α), (3) reducing elevated liver enzymes (aspartate transaminase, alanine transaminase, and ammonia), and (4) restoring liver histopathology. These findings suggest that everolimus protects the liver against hepatic IRI by way of activating autophagy, and thus could be a potential therapeutic agent for hepatic IRI. PMID:26814830

  18. Direct Evidence of Target Inhibition with anti-VEGF, EGFR, and mTOR Therapies in a Clinical Model of Wound Healing

    PubMed Central

    Jia, Jingquan; Dellinger, Andrew E.; Weiss, Eric S.; Bulusu, Anuradha; Rushing, Christel; Li, Haiyan; Howard, Leigh A.; Kaplan, Neal; Pang, Herbert; Hurwitz, Herbert I.; Nixon, Andrew B.

    2016-01-01

    Purpose In early clinical testing, most novel targeted anti-cancer therapies have limited toxicities and limited efficacy, which complicates dose and schedule selection for these agents. Confirmation of target inhibition is critical for rational drug development; however, repeated tumor biopsies are often impractical and peripheral blood mononuclear cells and normal skin are often inadequate surrogates for tumor tissue. Based upon the similarities of tumor and wound stroma, we have developed a clinical dermal granulation tissue model to evaluate novel targeted therapies. Experimental design A 4mm skin punch biopsy was used to stimulate wound healing and a repeat 5mm punch biopsy was used to harvest the resulting granulation tissue. This assay was performed at pre-treatment and on-treatment evaluating four targeted therapies, bevacizumab, everolimus, erlotinib, and panitumumab, in the context of three different clinical trials. Total and phosphorylated levels VEGFR2, S6RP, and EGFR were evaluated using ELISA-based methodologies. Results Significant and consistent inhibition of VEGF pathway (using VEGFR2 as the readout) was observed in granulation tissue biopsies from patients treated with bevacizumab and everolimus. Additionally, significant and consistent inhibition of mTOR pathway (using S6RP as the readout) was observed in patients treated with everolimus. Lastly, significant inhibition of EGFR pathway (using EGFR as the readout) was observed in patients treated with panitumumab, but this was not observed in patients treated with erlotinib. Conclusion Molecular analyses of dermal granulation tissue can be used as a convenient and quantitative pharmacodynamic biomarker platform for multiple classes of targeted therapies. PMID:25878330

  19. Notch signals positively regulate activity of the mTOR pathway in T-cell acute lymphoblastic leukemia

    PubMed Central

    Chan, Steven M.; Weng, Andrew P.; Tibshirani, Robert; Aster, Jon C.

    2007-01-01

    Constitutive Notch activation is required for the proliferation of a subgroup of T-cell acute lymphoblastic leukemia (T-ALL). Downstream pathways that transmit pro-oncogenic signals are not well characterized. To identify these pathways, protein microarrays were used to profile the phosphorylation state of 108 epitopes on 82 distinct signaling proteins in a panel of 13 T-cell leukemia cell lines treated with a gamma-secretase inhibitor (GSI) to inhibit Notch signals. The microarray screen detected GSI-induced hypophosphorylation of multiple signaling proteins in the mTOR pathway. This effect was rescued by expression of the intracellular domain of Notch and mimicked by dominant negative MAML1, confirming Notch specificity. Withdrawal of Notch signals prevented stimulation of the mTOR pathway by mitogenic factors. These findings collectively suggest that the mTOR pathway is positively regulated by Notch in T-ALL cells. The effect of GSI on the mTOR pathway was independent of changes in phosphatidylinositol-3 kinase and Akt activity, but was rescued by expression of c-Myc, a direct transcriptional target of Notch, implicating c-Myc as an intermediary between Notch and mTOR. T-ALL cell growth was suppressed in a highly synergistic manner by simultaneous treatment with the mTOR inhibitor rapamycin and GSI, which represents a rational drug combination for treating this aggressive human malignancy. PMID:17363738

  20. Radiation Recall Pneumonitis During Systemic Treatment With Everolimus.

    PubMed

    Clark, Douglas; Gauchan, Dron; Ramaekers, Ryan; Norvell, Max; Copur, Mehmet Sitki

    2014-01-01

    Radiation recall syndrome is an acute inflammatory reaction developing at anatomical sites of previously irradiated tissue, weeks to months after the completion of radiation therapy. The distribution pattern of inflammation typically involves, and remains limited to, the boundaries of prior radiation treatment fields. Several classical chemotherapy drugs have been reported to have the potential for causing radiation recall syndrome. With the increasing availability and expanding use of novel biologic and targeted therapy anticancer drugs, isolated reports of radiation recall syndrome secondary to this class of agents are starting to appear in the literature. We describe a case of everolimus-induced radiation recall pneumonitis in a patient with metastatic renal cell cancer. PMID:26629944

  1. mTor signaling is required for the formation of proliferating Müller glia-derived progenitor cells in the chick retina.

    PubMed

    Zelinka, Christopher P; Volkov, Leo; Goodman, Zachary A; Todd, Levi; Palazzo, Isabella; Bishop, William A; Fischer, Andy J

    2016-06-01

    We investigate the roles of mTor signaling in the formation of Müller glia-derived progenitor cells (MGPCs) in the chick retina. During embryonic development, pS6 (a readout of active mTor signaling) is present in early-stage retinal progenitors, differentiating amacrine and ganglion cells, and late-stage progenitors or maturing Müller glia. By contrast, pS6 is present at low levels in a few scattered cell types in mature, healthy retina. Following retinal damage, in which MGPCs are known to form, mTor signaling is rapidly activated in Müller glia. Inhibition of mTor in damaged retinas prevented the accumulation of pS6 in Müller glia and reduced numbers of proliferating MGPCs. Inhibition of mTor had no effect on MAPK signaling or on upregulation of the stem cell factor Klf4, whereas Pax6 upregulation was significantly reduced. Inhibition of mTor potently blocked the MGPC-promoting effects of Hedgehog, Wnt and glucocorticoid signaling in damaged retinas. In the absence of retinal damage, insulin, IGF1 and FGF2 induced pS6 in Müller glia, and this was blocked by mTor inhibitor. In FGF2-treated retinas, in which MGPCs are known to form, inhibition of mTor blocked the accumulation of pS6, the upregulation of Pax6 and the formation of proliferating MGPCs. We conclude that mTor signaling is required, but not sufficient, to stimulate Müller glia to give rise to proliferating progenitors, and the network of signaling pathways that drive the formation of MGPCs requires activation of mTor. PMID:27068108

  2. Finding a better drug for epilepsy: The mTOR pathway as an antiepileptogenic target

    PubMed Central

    Galanopoulou, Aristea S.; Gorter, Jan A.; Cepeda, Carlos

    2012-01-01

    Summary The mTOR signaling pathway regulates cell growth, differentiation, proliferation and metabolism. Loss of function mutations in upstream regulators of mTOR have been highly associated with dysplasias, epilepsy and neurodevelopmental disorders. These include tuberous sclerosis, which is due to mutations in TSC1 or TSC2 genes, mutations in phosphatase and tensin homolog (PTEN) as in Cowden syndrome, polyhydramnios, megalencephaly, symptomatic epilepsy syndrome (PMSE) due to mutations in the STE20-related kinase adaptor alpha (STRADalpha), and neurofibromatosis type 1 attributed to neurofibromin 1 mutations. Inhibition of the mTOR pathway with rapamycin may prevent epilepsy and improve the underlying pathology in mouse models with disrupted mTOR signaling, due to PTEN or TSC mutations. However the timing and duration of its administration appear critical in defining the seizure and pathology-related outcomes. Rapamycin application in human cortical slices from patients with cortical dysplasias reduces the 4-aminopyridine induced oscillations. In the multiple-hit model of infantile spasms, pulse high dose rapamycin administration can reduce the cortical overactivation of the mTOR pathway, suppresses spasms and has disease-modifying effects by partially improving cognitive deficits. In post-status epilepticus models of temporal lobe epilepsy, rapamycin may ameliorate the development of epilepsy-related pathology and reduce the expression of spontaneous seizures, but its effects depend on the timing and duration of administration, and possibly the model used. The observed recurrence of seizures and epilepsy-related pathology after rapamycin discontinuation suggests the need for continuous administration to maintain the benefit. However, the use of pulse administration protocols may be useful in certain age-specific epilepsy syndromes, like infantile spasms, whereas repetitive pulse rapamycin protocols may suffice to sustain a long-term benefit in genetic disorders

  3. The role of mTOR signaling in the regulation of protein synthesis and muscle mass during immobilization in mice

    PubMed Central

    You, Jae-Sung; Anderson, Garrett B.; Dooley, Matthew S.; Hornberger, Troy A.

    2015-01-01

    ABSTRACT The maintenance of skeletal muscle mass contributes substantially to health and to issues associated with the quality of life. It has been well recognized that skeletal muscle mass is regulated by mechanically induced changes in protein synthesis, and that signaling by mTOR is necessary for an increase in protein synthesis and the hypertrophy that occurs in response to increased mechanical loading. However, the role of mTOR signaling in the regulation of protein synthesis and muscle mass during decreased mechanical loading remains largely undefined. In order to define the role of mTOR signaling, we employed a mouse model of hindlimb immobilization along with pharmacological, mechanical and genetic means to modulate mTOR signaling. The results first showed that immobilization induced a decrease in the global rates of protein synthesis and muscle mass. Interestingly, immobilization also induced an increase in mTOR signaling, eIF4F complex formation and cap-dependent translation. Blocking mTOR signaling during immobilization with rapamycin not only impaired the increase in eIF4F complex formation, but also augmented the decreases in global protein synthesis and muscle mass. On the other hand, stimulating immobilized muscles with isometric contractions enhanced mTOR signaling and rescued the immobilization-induced decrease in global protein synthesis through a rapamycin-sensitive mechanism that was independent of ribosome biogenesis. Unexpectedly, the effects of isometric contractions were also independent of eIF4F complex formation. Similar to isometric contractions, overexpression of Rheb in immobilized muscles enhanced mTOR signaling, cap-dependent translation and global protein synthesis, and prevented the reduction in fiber size. Therefore, we conclude that the activation of mTOR signaling is both necessary and sufficient to alleviate the decreases in protein synthesis and muscle mass that occur during immobilization. Furthermore, these results indicate

  4. The role of mTOR signaling in the regulation of protein synthesis and muscle mass during immobilization in mice.

    PubMed

    You, Jae-Sung; Anderson, Garrett B; Dooley, Matthew S; Hornberger, Troy A

    2015-09-01

    The maintenance of skeletal muscle mass contributes substantially to health and to issues associated with the quality of life. It has been well recognized that skeletal muscle mass is regulated by mechanically induced changes in protein synthesis, and that signaling by mTOR is necessary for an increase in protein synthesis and the hypertrophy that occurs in response to increased mechanical loading. However, the role of mTOR signaling in the regulation of protein synthesis and muscle mass during decreased mechanical loading remains largely undefined. In order to define the role of mTOR signaling, we employed a mouse model of hindlimb immobilization along with pharmacological, mechanical and genetic means to modulate mTOR signaling. The results first showed that immobilization induced a decrease in the global rates of protein synthesis and muscle mass. Interestingly, immobilization also induced an increase in mTOR signaling, eIF4F complex formation and cap-dependent translation. Blocking mTOR signaling during immobilization with rapamycin not only impaired the increase in eIF4F complex formation, but also augmented the decreases in global protein synthesis and muscle mass. On the other hand, stimulating immobilized muscles with isometric contractions enhanced mTOR signaling and rescued the immobilization-induced decrease in global protein synthesis through a rapamycin-sensitive mechanism that was independent of ribosome biogenesis. Unexpectedly, the effects of isometric contractions were also independent of eIF4F complex formation. Similar to isometric contractions, overexpression of Rheb in immobilized muscles enhanced mTOR signaling, cap-dependent translation and global protein synthesis, and prevented the reduction in fiber size. Therefore, we conclude that the activation of mTOR signaling is both necessary and sufficient to alleviate the decreases in protein synthesis and muscle mass that occur during immobilization. Furthermore, these results indicate that the

  5. Everolimus Stabilizes Podocyte Microtubules via Enhancing TUBB2B and DCDC2 Expression

    PubMed Central

    Jeruschke, Stefanie; Jeruschke, Kay; DiStasio, Andrew; Karaterzi, Sinem; Büscher, Anja K.; Nalbant, Perihan; Klein-Hitpass, Ludger; Hoyer, Peter F.; Weiss, Jürgen; Stottmann, Rolf W.; Weber, Stefanie

    2015-01-01

    Background Glomerular podocytes are highly differentiated cells that are key components of the kidney filtration units. The podocyte cytoskeleton builds the basis for the dynamic podocyte cytoarchitecture and plays a central role for proper podocyte function. Recent studies implicate that immunosuppressive agents including the mTOR-inhibitor everolimus have a protective role directly on the stability of the podocyte actin cytoskeleton. In contrast, a potential stabilization of microtubules by everolimus has not been studied so far. Methods To elucidate mechanisms underlying mTOR-inhibitor mediated cytoskeletal rearrangements, we carried out microarray gene expression studies to identify target genes and corresponding pathways in response to everolimus. We analyzed the effect of everolimus in a puromycin aminonucleoside experimental in vitro model of podocyte injury. Results Upon treatment with puromycin aminonucleoside, microarray analysis revealed gene clusters involved in cytoskeletal reorganization, cell adhesion, migration and extracellular matrix composition to be affected. Everolimus was capable of protecting podocytes from injury, both on transcriptional and protein level. Rescued genes included tubulin beta 2B class IIb (TUBB2B) and doublecortin domain containing 2 (DCDC2), both involved in microtubule structure formation in neuronal cells but not identified in podocytes so far. Validating gene expression data, Western-blot analysis in cultured podocytes demonstrated an increase of TUBB2B and DCDC2 protein after everolimus treatment, and immunohistochemistry in healthy control kidneys confirmed a podocyte-specific expression. Interestingly, Tubb2bbrdp/brdp mice revealed a delay in glomerular podocyte development as showed by podocyte-specific markers Wilm’s tumour 1, Podocin, Nephrin and Synaptopodin. Conclusions Taken together, our study suggests that off-target, non-immune mediated effects of the mTOR-inhibitor everolimus on the podocyte cytoskeleton

  6. Inhibition of mTOR Pathway by Rapamycin Reduces Brain Damage in Rats Subjected to Transient Forebrain Ischemia

    PubMed Central

    Yang, Xiao; Hei, Changhun; Liu, Ping; Song, Yaozu; Thomas, Taylor; Tshimanga, Sylvie; Wang, Feng; Niu, Jianguo; Sun, Tao; Li, P. Andy

    2015-01-01

    The aims of this study are to clarify the role of mTOR in mediating cerebral ischemic brain damage and the effects of rapamycin on ischemic outcomes. Ten minutes of forebrain ischemia was induced in rats, and their brains were sampled after 3 h, 16 h, and 7 days reperfusion for histology, immunohistochemistry and biochemical analysis. Our data demonstrated that cerebral ischemia resulted in both apoptotic and necrotic neuronal death; cerebral ischemia and reperfusion led to significant increases of mRNA and protein levels of p-mTOR and its downstream p-P70S6K and p-S6; elevation of LC3-II, and release of cytochrome c into the cytoplasm in both the cortex and hippocampus. Inhibition of mTOR by rapamycin markedly reduced ischemia-induced damage; suppressed p-Akt, p-mTOR, p-P70S6K and p-S6 protein levels; decreased LC3-II and Beclin-1; and prevented cytochrome c release in the two structures. All together, these data provide evidence that cerebral ischemia activates mTOR and autophagy pathways. Inhibition of mTOR deactivates the mTOR pathway, suppresses autophagy, prevents cytochrome c release and reduces ischemic brain damage. PMID:26681922

  7. The role of mTOR signalling in the regulation of skeletal muscle mass in a rodent model of resistance exercise.

    PubMed

    Ogasawara, Riki; Fujita, Satoshi; Hornberger, Troy A; Kitaoka, Yu; Makanae, Yuhei; Nakazato, Koichi; Naokata, Ishii

    2016-01-01

    Resistance exercise (RE) activates signalling by the mammalian target of rapamycin (mTOR), and it has been suggested that rapamycin-sensitive mTOR signalling controls RE-induced changes in protein synthesis, ribosome biogenesis, autophagy, and the expression of peroxisome proliferator gamma coactivator 1 alpha (PGC-1α). However, direct evidence to support the aforementioned relationships is lacking. Therefore, in this study, we investigated the role of rapamycin-sensitive mTOR in the RE-induced activation of muscle protein synthesis, ribosome biogenesis, PGC-1α expression and hypertrophy. The results indicated that the inhibition of rapamycin-sensitive mTOR could prevent the induction of ribosome biogenesis by RE, but it only partially inhibited the activation of muscle protein synthesis. Likewise, the inhibition of rapamycin-sensitive mTOR only partially blocked the hypertrophic effects of chronic RE. Furthermore, both acute and chronic RE promoted an increase in PGC-1α expression and these alterations were not affected by the inhibition of rapamycin-sensitive mTOR. Combined, the results from this study not only establish that rapamycin-sensitive mTOR plays an important role in the RE-induced activation of protein synthesis and the induction of hypertrophy, but they also demonstrate that additional (rapamycin-sensitive mTOR-independent) mechanisms contribute to these fundamentally important events. PMID:27502839

  8. The role of mTOR signalling in the regulation of skeletal muscle mass in a rodent model of resistance exercise

    PubMed Central

    Ogasawara, Riki; Fujita, Satoshi; Hornberger, Troy A.; Kitaoka, Yu; Makanae, Yuhei; Nakazato, Koichi; Naokata, Ishii

    2016-01-01

    Resistance exercise (RE) activates signalling by the mammalian target of rapamycin (mTOR), and it has been suggested that rapamycin-sensitive mTOR signalling controls RE-induced changes in protein synthesis, ribosome biogenesis, autophagy, and the expression of peroxisome proliferator gamma coactivator 1 alpha (PGC-1α). However, direct evidence to support the aforementioned relationships is lacking. Therefore, in this study, we investigated the role of rapamycin-sensitive mTOR in the RE-induced activation of muscle protein synthesis, ribosome biogenesis, PGC-1α expression and hypertrophy. The results indicated that the inhibition of rapamycin-sensitive mTOR could prevent the induction of ribosome biogenesis by RE, but it only partially inhibited the activation of muscle protein synthesis. Likewise, the inhibition of rapamycin-sensitive mTOR only partially blocked the hypertrophic effects of chronic RE. Furthermore, both acute and chronic RE promoted an increase in PGC-1α expression and these alterations were not affected by the inhibition of rapamycin-sensitive mTOR. Combined, the results from this study not only establish that rapamycin-sensitive mTOR plays an important role in the RE-induced activation of protein synthesis and the induction of hypertrophy, but they also demonstrate that additional (rapamycin-sensitive mTOR-independent) mechanisms contribute to these fundamentally important events. PMID:27502839

  9. Endothelial Cell mTOR Complex-2 Regulates Sprouting Angiogenesis

    PubMed Central

    Farhan, Maikel A.; Carmine-Simmen, Katia; Lewis, John D.; Moore, Ronald B.; Murray, Allan G.

    2015-01-01

    Tumor neovascularization is targeted by inhibition of vascular endothelial growth factor (VEGF) or the receptor to prevent tumor growth, but drug resistance to angiogenesis inhibition limits clinical efficacy. Inhibition of the phosphoinositide 3 kinase pathway intermediate, mammalian target of rapamycin (mTOR), also inhibits tumor growth and may prevent escape from VEGF receptor inhibitors. mTOR is assembled into two separate multi-molecular complexes, mTORC1 and mTORC2. The direct effect of mTORC2 inhibition on the endothelium and tumor angiogenesis is poorly defined. We used pharmacological inhibitors and RNA interference to determine the function of mTORC2 versus Akt1 and mTORC1 in human endothelial cells (EC). Angiogenic sprouting, EC migration, cytoskeleton re-organization, and signaling events regulating matrix adhesion were studied. Sustained inactivation of mTORC1 activity up-regulated mTORC2-dependent Akt1 activation. In turn, ECs exposed to mTORC1-inhibition were resistant to apoptosis and hyper-responsive to renal cell carcinoma (RCC)-stimulated angiogenesis after relief of the inhibition. Conversely, mTORC1/2 dual inhibition or selective mTORC2 inactivation inhibited angiogenesis in response to RCC cells and VEGF. mTORC2-inactivation decreased EC migration more than Akt1- or mTORC1-inactivation. Mechanistically, mTORC2 inactivation robustly suppressed VEGF-stimulated EC actin polymerization, and inhibited focal adhesion formation and activation of focal adhesion kinase, independent of Akt1. Endothelial mTORC2 regulates angiogenesis, in part by regulation of EC focal adhesion kinase activity, matrix adhesion, and cytoskeletal remodeling, independent of Akt/mTORC1. PMID:26295809

  10. A sensitive high-throughput HPLC assay for simultaneous determination of everolimus and clobetasol propionate.

    PubMed

    Kamberi, Marika; Fu, Katherine; Lu, Jianmin; Chemaly, G Mike; Feder, Debra

    2008-01-01

    A novel sensitive high-throughput high-performance liquid chromatography assay is developed and validated for the simultaneous determination of everolimus and clobetasol propionate in pharmaceutical formulations. The chromatographic separation is achieved on a Zorbax Eclipse XDB-C18 reversed-phase column using a gradient elution, with solvent A: ammonium acetate (pH 6.8; 0.01 M) and solvent B: acetonitrile. The mean recovery ranges from 95.1% to 100.0% for clobetasol propionate and from 97.9% to 103.7% for everolimus. The limit of quantitation for each analyte is 0.02 microg/mL. The percent relative standard deviations are less than 3% for intra- and inter-day analyses. The proposed method can be used for the routine quality control of everolimus and clobetasol propionate in complex pharmaceutical formulations, especially the drug-delivery systems with a low total drug-load. PMID:18218184

  11. Assessing Metabolic Changes in Response to mTOR Inhibition in a Mantle Cell Lymphoma Xenograft Model Using AcidoCEST MRI

    PubMed Central

    Akhenblit, Paul J.; Hanke, Neale T.; Gill, Alexander; Persky, Daniel O.; Howison, Christine M.; Pagel, Mark D.; Baker, Amanda F.

    2016-01-01

    AcidoCEST magnetic resonance imaging (MRI) has previously been shown to measure tumor extracellular pH (pHe) with excellent accuracy and precision. This study investigated the ability of acidoCEST MRI to monitor changes in tumor pHe in response to therapy. To perform this study, we used the Granta 519 human mantle cell lymphoma cell line, which is an aggressive B-cell malignancy that demonstrates activation of the phosphatidylinositol-3-kinase/Akt/mammalian target of rapamycin (mTOR) pathway. We performed in vitro and in vivo studies using the Granta 519 cell line to investigate the efficacy and associated changes induced by the mTOR inhibitor, everolimus (RAD001). AcidoCEST MRI studies showed a statistically significant increase in tumor pHe of 0.10 pH unit within 1 day of initiating treatment, which foreshadowed a decrease in tumor growth of the Granta 519 xenograft model. AcidoCEST MRI then measured a decrease in tumor pHe 7 days after initiating treatment, which foreshadowed a return to normal tumor growth rate. Therefore, this study is a strong example that acidoCEST MRI can be used to measure tumor pHe that may serve as a marker for therapeutic efficacy of anticancer therapies. PMID:27140422

  12. Assessing Metabolic Changes in Response to mTOR Inhibition in a Mantle Cell Lymphoma Xenograft Model Using AcidoCEST MRI.

    PubMed

    Akhenblit, Paul J; Hanke, Neale T; Gill, Alexander; Persky, Daniel O; Howison, Christine M; Pagel, Mark D; Baker, Amanda F

    2016-01-01

    AcidoCEST magnetic resonance imaging (MRI) has previously been shown to measure tumor extracellular pH (pHe) with excellent accuracy and precision. This study investigated the ability of acidoCEST MRI to monitor changes in tumor pHe in response to therapy. To perform this study, we used the Granta 519 human mantle cell lymphoma cell line, which is an aggressive B-cell malignancy that demonstrates activation of the phosphatidylinositol-3-kinase/Akt/mammalian target of rapamycin (mTOR) pathway. We performed in vitro and in vivo studies using the Granta 519 cell line to investigate the efficacy and associated changes induced by the mTOR inhibitor, everolimus (RAD001). AcidoCEST MRI studies showed a statistically significant increase in tumor pHe of 0.10 pH unit within 1 day of initiating treatment, which foreshadowed a decrease in tumor growth of the Granta 519 xenograft model. AcidoCEST MRI then measured a decrease in tumor pHe 7 days after initiating treatment, which foreshadowed a return to normal tumor growth rate. Therefore, this study is a strong example that acidoCEST MRI can be used to measure tumor pHe that may serve as a marker for therapeutic efficacy of anticancer therapies. PMID:27140422

  13. Real-World Study of Everolimus in Advanced Progressive Neuroendocrine Tumors

    PubMed Central

    Panzuto, Francesco; Rinzivillo, Maria; Fazio, Nicola; de Braud, Filippo; Luppi, Gabriele; Zatelli, Maria Chiara; Lugli, Francesca; Tomassetti, Paola; Riccardi, Ferdinando; Nuzzo, Carmen; Brizzi, Maria Pia; Faggiano, Antongiulio; Zaniboni, Alberto; Nobili, Elisabetta; Pastorelli, Davide; Cascinu, Stefano; Merlano, Marco; Chiara, Silvana; Antonuzzo, Lorenzo; Funaioli, Chiara; Spada, Francesca; Pusceddu, Sara; Fontana, Annalisa; Ambrosio, Maria Rosaria; Cassano, Alessandra; Campana, Davide; Cartenì, Giacomo; Appetecchia, Marialuisa; Berruti, Alfredo; Colao, Annamaria; Falconi, Massimo

    2014-01-01

    Everolimus is a valid therapeutic option for neuroendocrine tumors (NETs); however, data in a real-world setting outside regulatory trials are sparse. The aim of this study was to determine everolimus tolerability and efficacy, in relation to previous treatments, in a compassionate use program. A total of 169 patients with advanced progressive NETs treated with everolimus were enrolled, including 85 with pancreatic NETs (pNETs) and 84 with nonpancreatic NETs (non-pNETs). Previous treatments included somatostatin analogs (92.9%), peptide receptor radionuclide therapy (PRRT; 50.3%), chemotherapy (49.7%), and PRRT and chemotherapy (22.8%). Overall, 85.2% of patients experienced adverse events (AEs), which were severe (grade 3–4) in 46.1%. The most frequent severe AEs were pneumonitis (8.3%), thrombocytopenia (7.7%), anemia (5.3%), and renal failure (3.5%). In patients previously treated with PRRT and chemotherapy, a 12-fold increased risk for severe toxicity was observed, with grade 3–4 AEs reported in 86.8% (vs. 34.3% in other patients). In addition, 63.3% of patients required temporarily everolimus discontinuation due to toxicity. Overall, 27.8% of patients died during a median follow-up of 12 months. Median progression-free survival (PFS) and overall survival (OS) were 12 months and 32 months, respectively. Similar disease control rates, PFS, and OS were reported in pNETs and non-pNETs. In the real-world setting, everolimus is safe and effective for the treatment of NETs of different origins. Higher severe toxicity occurred in patients previously treated with systemic chemotherapy and PRRT. This finding prompts caution when using this drug in pretreated patients and raises the issue of planning for everolimus before PRRT and chemotherapy in the therapeutic algorithm for advanced NETs. PMID:25117065

  14. Real-world study of everolimus in advanced progressive neuroendocrine tumors.

    PubMed

    Panzuto, Francesco; Rinzivillo, Maria; Fazio, Nicola; de Braud, Filippo; Luppi, Gabriele; Zatelli, Maria Chiara; Lugli, Francesca; Tomassetti, Paola; Riccardi, Ferdinando; Nuzzo, Carmen; Brizzi, Maria Pia; Faggiano, Antongiulio; Zaniboni, Alberto; Nobili, Elisabetta; Pastorelli, Davide; Cascinu, Stefano; Merlano, Marco; Chiara, Silvana; Antonuzzo, Lorenzo; Funaioli, Chiara; Spada, Francesca; Pusceddu, Sara; Fontana, Annalisa; Ambrosio, Maria Rosaria; Cassano, Alessandra; Campana, Davide; Cartenì, Giacomo; Appetecchia, Marialuisa; Berruti, Alfredo; Colao, Annamaria; Falconi, Massimo; Delle Fave, Gianfranco

    2014-09-01

    Everolimus is a valid therapeutic option for neuroendocrine tumors (NETs); however, data in a real-world setting outside regulatory trials are sparse. The aim of this study was to determine everolimus tolerability and efficacy, in relation to previous treatments, in a compassionate use program. A total of 169 patients with advanced progressive NETs treated with everolimus were enrolled, including 85 with pancreatic NETs (pNETs) and 84 with nonpancreatic NETs (non-pNETs). Previous treatments included somatostatin analogs (92.9%), peptide receptor radionuclide therapy (PRRT; 50.3%), chemotherapy (49.7%), and PRRT and chemotherapy (22.8%). Overall, 85.2% of patients experienced adverse events (AEs), which were severe (grade 3-4) in 46.1%. The most frequent severe AEs were pneumonitis (8.3%), thrombocytopenia (7.7%), anemia (5.3%), and renal failure (3.5%). In patients previously treated with PRRT and chemotherapy, a 12-fold increased risk for severe toxicity was observed, with grade 3-4 AEs reported in 86.8% (vs. 34.3% in other patients). In addition, 63.3% of patients required temporarily everolimus discontinuation due to toxicity. Overall, 27.8% of patients died during a median follow-up of 12 months. Median progression-free survival (PFS) and overall survival (OS) were 12 months and 32 months, respectively. Similar disease control rates, PFS, and OS were reported in pNETs and non-pNETs. In the real-world setting, everolimus is safe and effective for the treatment of NETs of different origins. Higher severe toxicity occurred in patients previously treated with systemic chemotherapy and PRRT. This finding prompts caution when using this drug in pretreated patients and raises the issue of planning for everolimus before PRRT and chemotherapy in the therapeutic algorithm for advanced NETs. PMID:25117065

  15. Syntaxin13 Expression Is Regulated by Mammalian Target of Rapamycin (mTOR) in Injured Neurons to Promote Axon Regeneration*

    PubMed Central

    Cho, Yongcheol; Di Liberto, Valentina; Carlin, Dan; Abe, Namiko; Li, Kathy H.; Burlingame, Alma L.; Guan, Shenheng; Michaelevski, Izhak; Cavalli, Valeria

    2014-01-01

    Injured peripheral neurons successfully activate intrinsic signaling pathways to enable axon regeneration. We have previously shown that dorsal root ganglia (DRG) neurons activate the mammalian target of rapamycin (mTOR) pathway following injury and that this activity enhances their axon growth capacity. mTOR plays a critical role in protein synthesis, but the mTOR-dependent proteins enhancing the regenerative capacity of DRG neurons remain unknown. To identify proteins whose expression is regulated by injury in an mTOR-dependent manner, we analyzed the protein composition of DRGs from mice in which we genetically activated mTOR and from mice with or without a prior nerve injury. Quantitative label-free mass spectrometry analyses revealed that the injury effects were correlated with mTOR activation. We identified a member of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) family of proteins, syntaxin13, whose expression was increased by injury in an mTOR-dependent manner. Increased syntaxin13 levels in injured nerves resulted from local protein synthesis and not axonal transport. Finally, knockdown of syntaxin13 in cultured DRG neurons prevented axon growth and regeneration. Together, these data suggest that syntaxin13 translation is regulated by mTOR in injured neurons to promote axon regeneration. PMID:24737317

  16. The mechanical activation of mTOR signaling: an emerging role for late endosome/lysosomal targeting.

    PubMed

    Jacobs, Brittany L; Goodman, Craig A; Hornberger, Troy A

    2014-02-01

    It is well recognized that mechanical signals play a critical role in the regulation of skeletal muscle mass, and the maintenance of muscle mass is essential for mobility, disease prevention and quality of life. Furthermore, over the last 15 years it has become established that signaling through a protein kinase called the mammalian (or mechanistic) target of rapamycin (mTOR) is essential for mechanically-induced changes in protein synthesis and muscle mass, however, the mechanism(s) via which mechanical stimuli regulate mTOR signaling have not been defined. Nonetheless, advancements are being made, and an emerging body of evidence suggests that the late endosome/lysosomal (LEL) system might play a key role in this process. Therefore, the purpose of this review is to summarize this body of evidence. Specifically, we will first explain why the Ras homologue enriched in brain (Rheb) and phosphatidic acid (PA) are considered to be direct activators of mTOR signaling. We will then describe the process of endocytosis and its involvement in the formation of LEL structures, as well as the evidence which indicates that mTOR and its direct activators (Rheb and PA) are all enriched at the LEL. Finally, we will summarize the evidence that has implicated the LEL in the regulation of mTOR by various growth regulatory inputs such as amino acids, growth factors and mechanical stimuli. PMID:24162376

  17. Chronic Repression of mTOR Complex 2 Induces Changes in the Gut Microbiota of Diet-induced Obese Mice.

    PubMed

    Jung, Mi-Ja; Lee, Jina; Shin, Na-Ri; Kim, Min-Soo; Hyun, Dong-Wook; Yun, Ji-Hyun; Kim, Pil Soo; Whon, Tae Woong; Bae, Jin-Woo

    2016-01-01

    Alterations in the gut microbiota play a crucial role in host physiology and metabolism; however, the molecular pathways underlying these changes in diet-induced obesity are unclear. Mechanistic target of rapamycin (mTOR) signaling pathway is associated with metabolic disorders such as obesity and type 2 diabetes (T2D). Therefore, we examined whether changes in the regulation of mTOR signaling induced by diet (a high-fat diet [HFD] or normal-chow diet) and/or therapeutics (resveratrol [a specific inhibitor of mTOR complex 1] or rapamycin [an inhibitor of both mTOR complex 1 and 2]) altered the composition of the gut microbiota in mice. Oral administration of resveratrol prevented glucose intolerance and fat accumulation in HFD-fed mice, whereas rapamycin significantly impaired glucose tolerance and exacerbated intestinal inflammation. The abundance of Lactococcus, Clostridium XI, Oscillibacter, and Hydrogenoanaerobacterium increased under the HFD condition; however, the abundance of these species declined after resveratrol treatment. Conversely, the abundance of unclassified Marinilabiliaceae and Turicibacter decreased in response to a HFD or rapamycin. Taken together, these results demonstrated that changes in the composition of intestinal microbiota induced by changes in mTOR activity correlate with obese and diabetic phenotypes. PMID:27471110

  18. Chronic Repression of mTOR Complex 2 Induces Changes in the Gut Microbiota of Diet-induced Obese Mice

    PubMed Central

    Jung, Mi-Ja; Lee, Jina; Shin, Na-Ri; Kim, Min-Soo; Hyun, Dong-Wook; Yun, Ji-Hyun; Kim, Pil Soo; Whon, Tae Woong; Bae, Jin-Woo

    2016-01-01

    Alterations in the gut microbiota play a crucial role in host physiology and metabolism; however, the molecular pathways underlying these changes in diet-induced obesity are unclear. Mechanistic target of rapamycin (mTOR) signaling pathway is associated with metabolic disorders such as obesity and type 2 diabetes (T2D). Therefore, we examined whether changes in the regulation of mTOR signaling induced by diet (a high-fat diet [HFD] or normal-chow diet) and/or therapeutics (resveratrol [a specific inhibitor of mTOR complex 1] or rapamycin [an inhibitor of both mTOR complex 1 and 2]) altered the composition of the gut microbiota in mice. Oral administration of resveratrol prevented glucose intolerance and fat accumulation in HFD-fed mice, whereas rapamycin significantly impaired glucose tolerance and exacerbated intestinal inflammation. The abundance of Lactococcus, Clostridium XI, Oscillibacter, and Hydrogenoanaerobacterium increased under the HFD condition; however, the abundance of these species declined after resveratrol treatment. Conversely, the abundance of unclassified Marinilabiliaceae and Turicibacter decreased in response to a HFD or rapamycin. Taken together, these results demonstrated that changes in the composition of intestinal microbiota induced by changes in mTOR activity correlate with obese and diabetic phenotypes. PMID:27471110

  19. Growth hormone abolishes the negative effects of everolimus on intestinal wound healing

    PubMed Central

    Küper, Markus Alexander; Trütschel, Sebastian; Weinreich, Jürgen; Königsrainer, Alfred; Beckert, Stefan

    2016-01-01

    AIM: To investigate whether the simultaneous treatment with human growth hormone (hGH) abolishes the negative effects of everolimus on anastomotic healing. METHODS: Forty-eight male Sprague-Dawley-rats were randomized to three groups of 16 animals each (I: vehicle; II: everolimus 3 mg/kg po; III: everolimus 3 mg/kg po + hGH 2.5 mg/kg sc). Animals were pre-treated with hGH and/or everolimus daily for seven days. Then a standard anastomosis was created in the descending colon and treatment was continued for another seven days. The anastomosis was resected in toto and the bursting pressure was assessed as a mechanical parameter of intestinal healing. Moreover, biochemical (Hydroxyproline, PCNA, MPO, MMP-2 and MMP-9) and histological (cell density, angiogenesis, amount of granulation tissue) parameters of intestinal healing were assessed. RESULTS: Anastomotic bursting pressure was significantly reduced by everolimus and a simultaneous treatment with hGH resulted in considerably higher values (I: 134 ± 19 mmHg, II: 85 ± 25 mmHg, III: 114 ± 25 mmHg; P < 0.05, I vs II; P = 0.09, I vs III and II vs III) Hydroxyproline concentration was significantly increased by hGH compared to everolimus alone (I: 14.9 ± 2.5 μg/mg, II: 8.9 ± 3.6 μg/mg, III: 11.9 ± 2.8 μg/mg; P < 0.05, I vs II/III and II vs III). The number of MPO-positive cells was reduced significantly by hGH compared to everolimus alone (I: 10 ± 1 n/mm², II: 15 ± 3 n/mm², III: 9 ± 2 n/mm²; P < 0.05, I vs II and II vs III), while the number of PCNA-positive cells were increased by hGH (I: 28 ± 3 /mm², II: 12 ± 3 /mm², III: 26 ± 12 /mm²; P < 0.05, I vs II and II vs III). Corresponding to these biochemical findings, HE-histology revealed significantly increased amount of granulation tissue in hGH-treated animals. CONCLUSION: Inhibition of intestinal wound healing by everolimus is partially neutralized by simultaeous treatment with hGH. Both inflammation as well as collagen

  20. mTOR Inhibitors Alone and in Combination with JAK2 Inhibitors Effectively Inhibit Cells of Myeloproliferative Neoplasms

    PubMed Central

    Martinelli, Serena; Tozzi, Lorenzo; Guglielmelli, Paola; Bosi, Alberto; Vannucchi, Alessandro M.

    2013-01-01

    Background Dysregulated signaling of the JAK/STAT pathway is a common feature of chronic myeloproliferative neoplasms (MPN), usually associated with JAK2V617F mutation. Recent clinical trials with JAK2 inhibitors showed significant improvements in splenomegaly and constitutional symptoms in patients with myelofibrosis but meaningful molecular responses were not documented. Accordingly, there remains a need for exploring new treatment strategies of MPN. A potential additional target for treatment is represented by the PI3K/AKT/mammalian target of rapamycin (mTOR) pathway that has been found constitutively activated in MPN cells; proof-of-evidence of efficacy of the mTOR inhibitor RAD001 has been obtained recently in a Phase I/II trial in patients with myelofibrosis. The aim of the study was to characterize the effects in vitro of mTOR inhibitors, used alone and in combination with JAK2 inhibitors, against MPN cells. Findings Mouse and human JAK2V617F mutated cell lines and primary hematopoietic progenitors from MPN patients were challenged with an allosteric (RAD001) and an ATP-competitive (PP242) mTOR inhibitor and two JAK2 inhibitors (AZD1480 and ruxolitinib). mTOR inhibitors effectively reduced proliferation and colony formation of cell lines through a slowed cell division mediated by changes in cell cycle transition to the S-phase. mTOR inhibitors also impaired the proliferation and prevented colony formation from MPN hematopoietic progenitors at doses significantly lower than healthy controls. JAK2 inhibitors produced similar antiproliferative effects in MPN cell lines and primary cells but were more potent inducers of apoptosis, as also supported by differential effects on cyclinD1, PIM1 and BcLxL expression levels. Co-treatment of mTOR inhibitor with JAK2 inhibitor resulted in synergistic activity against the proliferation of JAK2V617F mutated cell lines and significantly reduced erythropoietin-independent colony growth in patients with polycythemia vera

  1. Immunoregulatory Effects of Everolimus on In Vitro Alloimmune Responses

    PubMed Central

    Levitsky, Josh; Miller, Joshua; Huang, Xuemei; Gallon, Lorenzo; Leventhal, Joseph R.; Mathew, James M.

    2016-01-01

    Everolimus (EVL) is a novel mTOR-inhibitor similar to sirolimus (SRL) that is used in organ transplant recipients, often in combination with tacrolimus (TAC) or mycophenolate (MPA). The current study aims to determine its effects on regulatory T cells. Increasing concentrations of EVL, MPA and TAC alone or in combination were added to MLRs of healthy volunteers. Lymphoproliferation by 3H-TdR incorporation and the percentage of newly generated CD4+CD127-CD25+FOXP3+ (total Treg) and CD4+CD127-CD25HighFOXP3+ (natural Treg) in CFSE labeled responder cells were assessed by flow cytometry. In comparison to medium controls, EVL and other agents dose-dependently inhibited 3H-TdR incorporation in HLA-2DR-matched and HLA-mismatched MLRs (n = 3–10). However, EVL significantly amplified newly generated total and natural Tregs in CFSE labeled responder cells (p<0.05) at all concentrations, while MPA and SRL did this only at sub-therapeutic concentrations and inhibited at therapeutic levels. In contrast, TAC inhibited newly generated Tregs at all concentrations. When tested in combination with TAC, EVL failed to reverse TAC inhibition of Treg generation. Combinations of EVL and low concentrations of MPA inhibited proliferation and amplified Treg generation in an additive manner when compared to medium controls or each drug tested alone (p<0.05). The relative tolerogenic effect from high to low was EVL > SRL> MPA > TAC. If the results from these in vitro studies are extrapolated to clinical transplantation, it would suggest EVL plus low concentrations of MPA may be the most tolerogenic combination. PMID:27275747

  2. Discovery – Targeted Treatments and mTOR Inhibitors

    Cancer.gov

    Thanks to discovering the anticancer effects of mTOR inhibitors, cancer treatment for pNet, a rare type of pancreatic cancer, were revolutionized. Through clinical trials, NCI continues to investigate the life-saving potential of mTOR inhibitors.

  3. Biomedical Potential of mTOR Modulation by Nanoparticles.

    PubMed

    Hulea, Laura; Markovic, Zoran; Topisirovic, Ivan; Simmet, Thomas; Trajkovic, Vladimir

    2016-05-01

    Modulation of the mammalian target of rapamycin (mTOR), the principal regulator of cellular homeostasis, underlies the biological effects of engineered nanoparticles, including regulation of cell death/survival and metabolic responses. Understanding the mechanisms and biological actions of nanoparticle-mediated mTOR modulation may help in developing safe and efficient nanotherapeutics to fight human disease. PMID:26900005

  4. Hyperpolarized 13C MR spectroscopic imaging can be used to monitor Everolimus treatment in vivo in an orthotopic rodent model of glioblastoma

    PubMed Central

    Chaumeil, Myriam M.; Ozawa, Tomoko; Park, IlWoo; Scott, Kristen; James, C. David; Nelson, Sarah J.; Ronen, Sabrina M.

    2011-01-01

    Glioblastoma (GBM) is the most common and lethal primary malignant brain tumor in humans. Because the phosphatidylinositol-3-kinase (PI3K) signaling pathway is activated in more than 88% of GBM, new drugs which target this pathway, such as the mTOR inhibitor Everolimus, are currently in clinical trials. Early tumor response to molecularly targeted treatments remains challenging to assess non-invasively, because it is often associated with tumor stasis or slower tumor growth. Innovative neuroimaging methods are therefore critically needed to provide metabolic or functional information that is indicative of targeted therapeutic action at early time points during the course of treatment. In this study, we demonstrated for the first time that hyperpolarized (HP) 13C magnetic resonance spectroscopic imaging (MRSI) can be used on a clinical MR system to monitor early metabolic response of orthotopic GBM tumors to Everolimus treatment through measurement of the HP lactate-to-pyruvate ratios. The study was performed on a highly invasive non-enhancing orthotopic GBM tumor model in rats (GS-2 tumors), which replicates many fundamental features of human GBM tumors. Seven days after initiation of treatment there was a significant drop in the HP lactate-to-pyruvate ratio from the tumor tissue in treated animals relative to day 0 (67%±27% decrease). In the control group, no significant changes in the HP lactate-to-pyruvate ratios were observed. Importantly, at the 7 day time point, conventional MR imaging (MRI) was unable to detect a significant difference in tumor size between control and treated groups. Inhibition of tumor growth by conventional MRI was observed from day 15 of treatment. This implies that the decrease in the HP lactate-to-pyruvate ratio could be detected before any treatment-induced inhibition of tumor growth. Using immunohistochemical staining to further examine tumor response to treatment, we found that the decrease in the HP lactate-to-pyruvate ratio was

  5. Paclitaxel-Eluting versus Everolimus-Eluting Coronary Stents in Diabetes.

    PubMed

    2016-07-28

    Paclitaxel-Eluting versus Everolimus-Eluting Coronary Stents in Diabetes Original Article, N Engl J Med 2015;373:1709-1719. In the list of authors (page 1709), the surname Abhaychand should have been Abhaichand. The article is correct at NEJM.org. PMID:27464221

  6. mTOR pathway in colorectal cancer: an update

    PubMed Central

    Francipane, Maria Giovanna; Lagasse, Eric

    2014-01-01

    The mammalian target of rapamycin (mTOR) has emerged as a potential target for drug development, particularly due to the fact that it plays such a crucial role in cancer biology. In addition, next-generation mTOR inhibitors have become available, marking an exciting new phase in mTOR-based therapy. However, the verdict on their therapeutic efectiveness remains unclear. Here we review phosphatidylinositol-3-kinase (PI3K)/Akt/mTOR signaling as one of the primary mechanisms for sustaining tumor outgrowth and metastasis, recent advances in the development of mTOR inhibitors, and current studies addressing mTOR activation/inhibition in colorectal cancer (CRC). We will also discuss our recent comparative study of diferent mTOR inhibitors in a population of colon cancer stem cells (CSCs), and current major challenges for achieving individualized drug therapy using kinase inhibitors. PMID:24393708

  7. Regulation of Immune Responses by mTOR

    PubMed Central

    Powell, Jonathan D.; Pollizzi, Kristen N.; Heikamp, Emily B.; Horton, Maureen R.

    2013-01-01

    mTOR is an evolutionarily conserved serine/threonine kinase that plays a central role in integrating environmental cues in the form of growth factors, amino acids, and energy. In the study of the immune system, mTOR is emerging as a critical regulator of immune function because of its role in sensing and integrating cues from the immune microenvironment. With the greater appreciation of cellular metabolism as an important regulator of immune cell function, mTOR is proving to be a vital link between immune function and metabolism. In this review, we discuss the ability of mTOR to direct the adaptive immune response. Specifically, we focus on the role of mTOR in promoting differentiation, activation, and function in T cells, B cells, and antigen-presenting cells. PMID:22136167

  8. mTOR, translational control and human disease.

    PubMed

    Tee, Andrew R; Blenis, John

    2005-02-01

    Many human diseases occur when the precise regulation of cell growth (cell mass/size) and proliferation (rates of cell division) is compromised. This review highlights those human disorders that occur as a result of inappropriate cellular signal transduction through the mammalian target of rapamycin (mTOR), a major pathway that coordinates proper cell growth and proliferation by regulating ribosomal biogenesis and protein translation. Recent studies reveal that the tuberous sclerosis complex (TSC)-1/2, PTEN, and LKB1 tumor suppressor proteins tightly control mTOR. Loss of these tumor suppressors leads to an array of hamartoma syndromes as a result of heightened mTOR signaling. Since mTOR plays a pivotal role in maintaining proper cell size and growth, dysregulation of mTOR signaling results in these benign tumor syndromes and an array of other human disorders. PMID:15659337

  9. Everolimus in combination with cyclosporin a as pre- and posttransplantation immunosuppressive therapy in nonmyeloablative allogeneic hematopoietic stem cell transplantation.

    PubMed

    Junghanss, Christian; Rathsack, Susanne; Wacke, Rainer; Weirich, Volker; Vogel, Heike; Drewelow, Bernd; Mueller, Sabrina; Altmann, Simone; Freund, Mathias; Lange, Sandra

    2012-07-01

    Everolimus (RAD001) is an mTOR inhibitor that has been successfully used as an immunosuppressant in solid-organ transplantation. Data in allogeneic hematopoietic stem cell transplantation (HSCT) is limited. This study aimed to investigate pharmacokinetics, safety, and efficacy of RAD001 in a canine allogeneic HSCT model. First, pharmacokinetics of RAD001 were performed in healthy dogs in order to determine the appropriate dosing. Doses of 0.25 mg RAD001 twice daily in combination with 15 mg/kg cyclosporin A (CsA) twice daily were identified as appropriate starting doses to achieve the targeted range of RAD001 (3-8 μg/L) when orally administered. Subsequently, 10 dogs were transplanted using 2 Gy total body irradiation (TBI) for conditioning and 0.25 mg RAD001 twice daily plus 15 mg/kg CsA twice daily for pre- and posttransplantation immunosuppression. Seven of the 10 transplanted dogs were maintained at the starting RAD001 dose throughout the study. For the remaining 3 dogs, dose adjustments were necessary. RAD001 accumulation over time did not occur. All dogs initially engrafted. Five dogs eventually rejected the graft (weeks 10, 10, 13, 27, and 56). Two dogs died of pneumonia (weeks 8 and 72) but were chimeric until then. Total cholesterol rose from median 4.1 mmol/L (3.5-5.7 mmol/L) before HSCT to 6.0 mmol/l (5.0-8.5 mmol/l) at day 21 after HSCT, but remained always within normal range. Changes in creatinine and triglyceride values were not observed. Long-term engraftment rates were inferior to sirolimus/CsA and mycophenolate mofetil (MMF)/CsA regimen, respectively. RAD001/CsA caused a more pronounced reduction of platelet counts to median 2 × 10(9)/L (range: 0-21 × 10(9)/L) and longer time to platelet recovery of 21 days (range: 14-24 days) compared with MMF/CsA. CsA c(2h) levels were significantly enhanced in the RAD001/CsA regimen, but c(0h) and area under the curve from 0 to 12 hours (AUC(0-12h)) values did not differ compared with an MMF

  10. TGF-β inhibits the activation and functions of NK cells by repressing the mTOR pathway.

    PubMed

    Viel, Sébastien; Marçais, Antoine; Guimaraes, Fernando Souza-Fonseca; Loftus, Roisin; Rabilloud, Jessica; Grau, Morgan; Degouve, Sophie; Djebali, Sophia; Sanlaville, Amélien; Charrier, Emily; Bienvenu, Jacques; Marie, Julien C; Caux, Christophe; Marvel, Jacqueline; Town, Liam; Huntington, Nicholas D; Bartholin, Laurent; Finlay, David; Smyth, Mark J; Walzer, Thierry

    2016-02-16

    Transforming growth factor-β (TGF-β) is a major immunosuppressive cytokine that maintains immune homeostasis and prevents autoimmunity through its antiproliferative and anti-inflammatory properties in various immune cell types. We provide genetic, pharmacologic, and biochemical evidence that a critical target of TGF-β signaling in mouse and human natural killer (NK) cells is the serine and threonine kinase mTOR (mammalian target of rapamycin). Treatment of mouse or human NK cells with TGF-β in vitro blocked interleukin-15 (IL-15)-induced activation of mTOR. TGF-β and the mTOR inhibitor rapamycin both reduced the metabolic activity and proliferation of NK cells and reduced the abundances of various NK cell receptors and the cytotoxic activity of NK cells. In vivo, constitutive TGF-β signaling or depletion of mTOR arrested NK cell development, whereas deletion of the TGF-β receptor subunit TGF-βRII enhanced mTOR activity and the cytotoxic activity of the NK cells in response to IL-15. Suppression of TGF-β signaling in NK cells did not affect either NK cell development or homeostasis; however, it enhanced the ability of NK cells to limit metastases in two different tumor models in mice. Together, these results suggest that the kinase mTOR is a crucial signaling integrator of pro- and anti-inflammatory cytokines in NK cells. Moreover, we propose that boosting the metabolic activity of antitumor lymphocytes could be an effective strategy to promote immune-mediated tumor suppression. PMID:26884601

  11. Denervation atrophy is independent from Akt and mTOR activation and is not rescued by myostatin inhibition.

    PubMed

    MacDonald, Elizabeth M; Andres-Mateos, Eva; Mejias, Rebeca; Simmers, Jessica L; Mi, Ruifa; Park, Jae-Sung; Ying, Stephanie; Hoke, Ahmet; Lee, Se-Jin; Cohn, Ronald D

    2014-04-01

    The purpose of our study was to compare two acquired muscle atrophies and the use of myostatin inhibition for their treatment. Myostatin naturally inhibits skeletal muscle growth by binding to ActRIIB, a receptor on the cell surface of myofibers. Because blocking myostatin in an adult wild-type mouse induces profound muscle hypertrophy, we applied a soluble ActRIIB receptor to models of disuse (limb immobilization) and denervation (sciatic nerve resection) atrophy. We found that treatment of immobilized mice with ActRIIB prevented the loss of muscle mass observed in placebo-treated mice. Our results suggest that this protection from disuse atrophy is regulated by serum and glucocorticoid-induced kinase (SGK) rather than by Akt. Denervation atrophy, however, was not protected by ActRIIB treatment, yet resulted in an upregulation of the pro-growth factors Akt, SGK and components of the mTOR pathway. We then treated the denervated mice with the mTOR inhibitor rapamycin and found that, despite a reduction in mTOR activation, there is no alteration of the atrophy phenotype. Additionally, rapamycin prevented the denervation-induced upregulation of the mTORC2 substrates Akt and SGK. Thus, our studies show that denervation atrophy is not only independent from Akt, SGK and mTOR activation but also has a different underlying pathophysiological mechanism than disuse atrophy. PMID:24504412

  12. Hypoxia Increases IGFBP-1 Phosphorylation Mediated by mTOR Inhibition.

    PubMed

    Damerill, Ian; Biggar, Kyle K; Abu Shehab, Majida; Li, Shawn Shun-Cheng; Jansson, Thomas; Gupta, Madhulika B

    2016-02-01

    In fetal growth restriction (FGR), fetal growth is limited by reduced nutrient and oxygen supply. Insulin-like growth factor I (IGF-I) is a key regulator of fetal growth and IGF binding protein -1(IGFBP-1) is the principal regulator of fetal IGF-I bioavailability. Phosphorylation enhances IGFBP-1's affinity for IGF-I. Hypoxia induces IGFBP-1 hyperphosphorylation, markedly decreasing IGF-I bioavailability. We recently reported that fetal liver IGFBP-1 hyperphosphorylation is associated with inhibition of the mechanistic target of rapamycin (mTOR) in a nonhuman primate model of FGR. Here, we test the hypothesis that IGFBP-1 hyperphosphorylation in response to hypoxia is mediated by mTOR inhibition. We inhibited mTOR either by rapamycin or small interfering RNA (siRNA) targeting raptor (mTOR complex [mTORC]1) and/or rictor (mTORC2) in HepG2 cells cultured under hypoxia (1% O2) or basal (20% O2) conditions. Conversely, we activated mTORC1 or mTORC1+mTORC2 by silencing endogenous mTOR inhibitors (tuberous sclerosis complex 2/DEP-domain-containing and mTOR-interacting protein). Immunoblot analysis demonstrated that both hypoxia and inhibition of mTORC1 and/or mTORC2 induced similar degrees of IGFBP-1 phosphorylation at Ser101/119/169 and reduced IGF-I receptor autophosphorylation. Activation of mTORC1+mTORC2 or mTORC1 alone prevented IGFBP-1 hyperphosphorylation in response to hypoxia. Multiple reaction monitoring-mass spectrometry showed that rapamycin and/or hypoxia increased phosphorylation also at Ser98 and at a novel site Ser174. In silico structural analysis indicated that Ser174 was in close proximity to the IGF-binding site. Together, we demonstrate that signaling through the mTORC1 or mTORC2 pathway is sufficient to induce IGFBP-1 hyperphosphorylation in response to hypoxia. This study provides novel understanding of the cellular mechanism that controls fetal IGFBP-1 phosphorylation in hypoxia, and we propose that mTOR inhibition constitutes a mechanistic link

  13. Impact of dual mTORC1/2 mTOR kinase inhibitor AZD8055 on acquired endocrine resistance in breast cancer in vitro

    PubMed Central

    2014-01-01

    Introduction Upregulation of PI3K/Akt/mTOR signalling in endocrine-resistant breast cancer (BC) has identified mTOR as an attractive target alongside anti-hormones to control resistance. RAD001 (everolimus/Afinitor®), an allosteric mTOR inhibitor, is proving valuable in this setting; however, some patients are inherently refractory or relapse during treatment requiring alternative strategies. Here we evaluate the potential for novel dual mTORC1/2 mTOR kinase inhibitors, exemplified by AZD8055, by comparison with RAD001 in ER + endocrine resistant BC cells. Methods In vitro models of tamoxifen (TamR) or oestrogen deprivation resistance (MCF7-X) were treated with RAD001 or AZD8055 alone or combined with anti-hormone fulvestrant. Endpoints included growth, cell proliferation (Ki67), viability and migration, with PI3K/AKT/mTOR signalling impact monitored by Western blotting. Potential ER cross-talk was investigated by immunocytochemistry and RT-PCR. Results RAD001 was a poor growth inhibitor of MCF7-derived TamR and MCF7-X cells (IC50 ≥1 μM), rapidly inhibiting mTORC1 but not mTORC2/AKT signalling. In contrast AZD8055, which rapidly inhibited both mTORC1 and mTORC2/AKT activity, was a highly effective (P <0.001) growth inhibitor of TamR (IC50 18 nM) and MCF7-X (IC50 24 nM), and of a further T47D-derived tamoxifen resistant model T47D-tamR (IC50 19 nM). AZD8055 significantly (P <0.05) inhibited resistant cell proliferation, increased cell death and reduced migration. Furthermore, dual treatment of TamR or MCF7-X cells with AZD8055 plus fulvestrant provided superior control of resistant growth versus either agent alone (P <0.05). Co-treating with AZD8055 alongside tamoxifen (P <0.01) or oestrogen deprivation (P <0.05) also effectively inhibited endocrine responsive MCF-7 cells. Although AZD8055 inhibited oestrogen receptor (ER) ser167 phosphorylation in TamR and MCF7-X, it had no effect on ER ser118 activity or expression of several ER-regulated genes

  14. Efficacy and Safety of an Everolimus- vs. a Mycophenolate Mofetil-Based Regimen in Pediatric Renal Transplant Recipients

    PubMed Central

    Brunkhorst, Lena Caroline; Fichtner, Alexander; Höcker, Britta; Burmeister, Greta; Ahlenstiel-Grunow, Thurid; Krupka, Kai; Bald, Martin; Zapf, Antonia

    2015-01-01

    Introduction Data on the efficacy and safety of everolimus in pediatric renal transplantation compared to other immunosuppressive regimens are scarce. Patients/Methods We therefore performed a multicenter, observational, matched cohort study over 4 years post-transplant in 35 patients on everolimus plus low-dose cyclosporine, who were matched (1:2) with a control group of 70 children receiving a standard-dose calcineurin-inhibitor- and mycophenolate mofetil-based regimen. Results Corticosteroids were withdrawn in 83% in the everolimus vs. 39% in the control group (p<0.001). Patient and graft survival were comparable. The rate of biopsy-proven acute rejection episodes Banff score ≥ IA during the first year post-transplant was 6% in the everolimus vs. 13% in the control group (p = 0.23). The rate of de novo donor-specific HLA antibodies (11% in everolimus, 18% in controls) was comparable (p = 0.55). At 4 years post-transplant, mean eGFR in the everolimus group was 56±33 ml/min per 1.73 m² vs. 63±22 ml/min per 1.73 m² in the control group (p = 0.14). Everolimus therapy was associated with less BK polyomavirus replication (3% vs. 17% in controls; p = 0.04), but with a higher percentage of arterial hypertension and more hyperlipidemia (p<0.001). Conclusion In pediatric renal transplantation, an everolimus-based regimen with low-dose cyclosporine yields comparable four year results as a standard regimen, but with a different side effect profile. PMID:26407177

  15. Renal function improvement in liver transplant recipients after early everolimus conversion: A clinical practice cohort study in Spain.

    PubMed

    Bilbao, Itxarone; Salcedo, Magdalena; Gómez, Miguel Angel; Jimenez, Carlos; Castroagudín, Javier; Fabregat, Joan; Almohalla, Carolina; Herrero, Ignacio; Cuervas-Mons, Valentín; Otero, Alejandra; Rubín, Angel; Miras, Manuel; Rodrigo, Juan; Serrano, Trinidad; Crespo, Gonzalo; De la Mata, Manuel; Bustamante, Javier; Gonzalez-Dieguez, M Luisa; Moreno, Antonia; Narvaez, Isidoro; Guilera, Magda

    2015-08-01

    A national, multicenter, retrospective study was conducted to assess the results obtained for liver transplant recipients with conversion to everolimus in daily practice. The study included 477 recipients (481 transplantations). Indications for conversion to everolimus were renal dysfunction (32.6% of cases), hepatocellular carcinoma (HCC; 30.2%; prophylactic treatment for 68.9%), and de novo malignancy (29.7%). The median time from transplantation to conversion to everolimus was 68.7 months for de novo malignancy, 23.8 months for renal dysfunction, and 7.1 months for HCC and other indications. During the first year of treatment, mean everolimus trough levels were 5.4 (standard deviation [SD], 2.7) ng/mL and doses remained stable (1.5 mg/day) from the first month after conversion. An everolimus monotherapy regimen was followed by 28.5% of patients at 12 months. Patients with renal dysfunction showed a glomerular filtration rate (4-variable Modification of Diet in Renal Disease) increase of 10.9 mL (baseline mean, 45.8 [SD, 25.3] versus 57.6 [SD, 27.6] mL/minute/1.73 m(2) ) at 3 months after everolimus initiation (P < 0.001), and 6.8 mL at 12 months. Improvement in renal function was higher in patients with early conversion (<1 year). Adverse events were the primary reason for discontinuation in 11.2% of cases. The probability of survival at 3 years after conversion to everolimus was 83.0%, 71.1%, and 59.5% for the renal dysfunction, de novo malignancy, and HCC groups, respectively. Everolimus is a viable option for the treatment of renal dysfunction, and earlier conversion is associated with better recovery of renal function. Prospective studies are needed to confirm advantages in patients with malignancy. PMID:25990257

  16. Deregulation of mTOR signaling is involved in thymic lymphoma development in Atm-/- mice

    SciTech Connect

    Kuang, Xianghong; Shen, Jianjun; Wong, Paul K.Y.; Yan, Mingshan

    2009-06-05

    Abnormal thymocyte development with thymic lymphomagenesis inevitably occurs in Atm-/- mice, indicating that ATM plays a pivotal role in regulating postnatal thymocyte development and preventing thymic lymphomagenesis. The mechanism for ATM controls these processes is unclear. We have shown previously that c-Myc, an oncoprotein regulated by the mammalian target of rapamycin (mTOR), is overexpressed in Atm-/- thymocytes. Here, we show that inhibition of mTOR signaling with its specific inhibitor, rapamycin, suppresses normal thymocyte DNA synthesis by downregulating 4EBP1, but not S6K, and that 4EBP1 phosphorylation and cyclin D1 expression are coordinately increased in Atm-/- thymocytes. Administration of rapamycin to Atm-/- mice attenuates elevated phospho-4EBP1, c-Myc and cyclin D1 in their thymocytes, and delays thymic lymphoma development. These results indicate that mTOR downstream effector 4EBP1 is essential for normal thymocyte proliferation, but deregulation of 4EBP1 in Atm deficiency is a major factor driving thymic lymphomagenesis in the animals.

  17. Regulation of mTOR by mechanically induced signaling events in skeletal muscle.

    PubMed

    Hornberger, Troy Alan; Sukhija, Kunal Balu; Chien, Shu

    2006-07-01

    Mechanical stimuli play a major role in the regulation of skeletal muscle mass, and the maintenance of muscle mass contributes significantly to disease prevention and the quality of life. Although a link between mechanical stimuli and the regulation of muscle mass has been recognized for decades, the mechanisms involved in converting mechanical information into the molecular events that control this process have not been defined. Nevertheless, significant advancements are being made in this field, and it has recently been established that signaling through a rapamycin-sensitive pathway is necessary for mechanically induced growth of skeletal muscle. Since rapamycin is a highly specific inhibitor of a protein kinase called the mammalian target of rapamycin (mTOR), many investigators have concluded that mTOR signaling is necessary for the mechanically induced growth of skeletal muscle. In this review, we have summarized the current knowledge regarding how mechanical stimuli activate mTOR signaling, discussed the newly discovered role of phospholipase D (PLD) and phosphatidic acid (PA) in this pathway, and considered the potential roles of PLD and PA in the mechanical regulation of skeletal muscle mass. PMID:16855395

  18. Arrest of Myelination and Reduced Axon Growth when Schwann Cells Lack mTOR

    PubMed Central

    Sherman, Diane L.; Krols, Michiel; Wu, Lai-Man; Grove, Matthew; Nave, Klaus-Armin; Gangloff, Yann-Gaël; Brophy, Peter J.

    2014-01-01

    In developing peripheral nerves differentiating Schwann cells sort individual axons from bundles and ensheath them to generate multiple layers of myelin. In recent years there has been an increasing understanding of the extracellular and intracellular factors that initiate and stimulate Schwann cell myelination together with a growing appreciation of some of the signalling pathways involved. However, our knowledge of how Schwann cell growth is regulated during myelination is still incomplete. The mammalian target of rapamycin (mTOR) is a core kinase in two major complexes, mTORC1 and mTORC2, that regulate cell growth and differentiation in a variety of mammalian cells. Here we show that elimination of mTOR from murine Schwann cells prevented neither radial sorting nor the initiation of myelination. However, normal post-natal growth of myelinating Schwann cells, both radially and longitudinally, was highly retarded. The myelin sheath in the mutant was much thinner than normal; nevertheless, sheath thickness relative to axon diameter (g-ratio) remained constant in both wild-type and mutant nerves from P14 to P90. Although axon diameters were normal in the mutant at the initiation of myelination, further growth as myelination proceeded was retarded, and this was associated with reduced phosphorylation of neurofilaments. Consistent with thinner axonal diameters and internodal lengths, conduction velocities in mutant quadriceps nerves were also reduced. These data establish a critical role for mTOR signalling in both the longitudinal and radial growth of the myelinating Schwann cell. PMID:22302821

  19. Arrest of myelination and reduced axon growth when Schwann cells lack mTOR.

    PubMed

    Sherman, Diane L; Krols, Michiel; Wu, Lai-Man N; Grove, Matthew; Nave, Klaus-Armin; Gangloff, Yann-Gaël; Brophy, Peter J

    2012-02-01

    In developing peripheral nerves, differentiating Schwann cells sort individual axons from bundles and ensheath them to generate multiple layers of myelin. In recent years, there has been an increased understanding of the extracellular and intracellular factors that initiate and stimulate Schwann cell myelination, together with a growing appreciation of some of the signaling pathways involved. However, our knowledge of how Schwann cell growth is regulated during myelination is still incomplete. The mammalian target of rapamycin (mTOR) is a core kinase in two major complexes, mTORC1 and mTORC2, that regulate cell growth and differentiation in a variety of mammalian cells. Here we show that elimination of mTOR from murine Schwann cells prevented neither radial sorting nor the initiation of myelination. However, normal postnatal growth of myelinating Schwann cells, both radially and longitudinally, was highly retarded. The myelin sheath in the mutant was much thinner than normal; nevertheless, sheath thickness relative to axon diameter (g-ratio) remained constant in both wild-type and mutant nerves from P14 to P90. Although axon diameters were normal in the mutant at the initiation of myelination, further growth as myelination proceeded was retarded, and this was associated with reduced phosphorylation of neurofilaments. Consistent with thinner axonal diameters and internodal lengths, conduction velocities in mutant quadriceps nerves were also reduced. These data establish a critical role for mTOR signaling in both the longitudinal and radial growth of the myelinating Schwann cell. PMID:22302821

  20. mTOR expression in human testicular seminoma.

    PubMed

    Yaba, A; Bozkurt, E R; Demir, N

    2016-08-01

    The mammalian target of rapamycin (TOR) has been implicated in the control of different stressors, growth factors, nutrients and hormones, participating in the control of key cellular functions. Controlling this many pathways poses mTOR signalling as a potential new target in new treatment strategies for multiple cancer types. mTOR components could potentially mislocated in tumour cells, which could lead to activation of signalling pathway that should not be active. Therefore, we aimed to show localisation of mTOR signal proteins in testicular seminoma. Tumoural testicular tissues were obtained from 10 patients with unilateral classic seminoma undergoing to therapeutic orchidectomy and compared with control human testicular tissues. Upon immunohistochemical evaluation, we detected mTOR and p-mTOR (serine 2448), P70S6K, p-P70S6K, PKCalpha and p-PKCalpha, CD36 and MAPLC3 proteins in the cytoplasm of Sertoli cells in the seminiferous tubules. We also showed cytoplasmic perinuclear staining in seminoma cells. This study demonstrated the interaction of mTOR signalling pathway and testicular seminoma by showing intense cytoplasmic mTOR pathway proteins immunoreactivity in the seminoma, for the first time in humans. Therefore, we suggested that mTOR signalling components could create new clinical targets for treatment of testicular seminoma patients and male infertility in the future. PMID:26648340

  1. Modulation of the protein kinase activity of mTOR.

    PubMed

    Lawrence, J C; Lin, T A; McMahon, L P; Choi, K M

    2004-01-01

    mTOR is a founding member of a family of protein kinases having catalytic domains homologous to those in phosphatidylinositol 3-OH kinase. mTOR participates in the control by insulin of the phosphorylation of lipin, which is required for adipocyte differentiation, and the two translational regulators, p70S6K and PHAS-I. The phosphorylation of mTOR, itself, is stimulated by insulin in Ser2448, a site that is also phosphorylated by protein kinase B (PKB) in vitro and in response to activation of PKB activity in vivo. Ser2448 is located in a short stretch of amino acids not found in the two TOR proteins in yeast. A mutant mTOR lacking this stretch exhibited increased activity, and binding of the antibody, mTAb-1, to this region markedly increased mTOR activity. In contrast, rapamycin-FKBP12 inhibited mTOR activity towards both PHAS-I and p70S6K, although this complex inhibited the phosphorylation of some sites more than that of others. Mutating Ser2035 to Ile in the FKBP12-rapamycin binding domain rendered mTOR resistant to inhibition by rapamycin. Unexpectedly, this mutation markedly decreased the ability of mTOR to phosphorylate certain sites in both PHAS-I and p70S6K. The results support the hypotheses that rapamycin disrupts substrate recognition instead of directly inhibiting phosphotransferase activity and that mTOR activity in cells is controlled by the phosphorylation of an inhibitory regulatory domain containing the mTAb-1 epitope. PMID:14560959

  2. Activation of mTOR (mechanistic target of rapamycin) in rheumatic diseases.

    PubMed

    Perl, Andras

    2016-03-01

    Mechanistic target of rapamycin (mTOR, also known as mammalian target of rapamycin) is a ubiquitous serine/threonine kinase that regulates cell growth, proliferation and survival. These effects are cell-type-specific, and are elicited in response to stimulation by growth factors, hormones and cytokines, as well as to internal and external metabolic cues. Rapamycin was initially developed as an inhibitor of T-cell proliferation and allograft rejection in the organ transplant setting. Subsequently, its molecular target (mTOR) was identified as a component of two interacting complexes, mTORC1 and mTORC2, that regulate T-cell lineage specification and macrophage differentiation. mTORC1 drives the proinflammatory expansion of T helper (TH) type 1, TH17, and CD4(-)CD8(-) (double-negative, DN) T cells. Both mTORC1 and mTORC2 inhibit the development of CD4(+)CD25(+)FoxP3(+) T regulatory (TREG) cells and, indirectly, mTORC2 favours the expansion of T follicular helper (TFH) cells which, similarly to DN T cells, promote B-cell activation and autoantibody production. In contrast to this proinflammatory effect of mTORC2, mTORC1 favours, to some extent, an anti-inflammatory macrophage polarization that is protective against infections and tissue inflammation. Outside the immune system, mTORC1 controls fibroblast proliferation and chondrocyte survival, with implications for tissue fibrosis and osteoarthritis, respectively. Rapamycin (which primarily inhibits mTORC1), ATP-competitive, dual mTORC1/mTORC2 inhibitors and upstream regulators of the mTOR pathway are being developed to treat autoimmune, hyperproliferative and degenerative diseases. In this regard, mTOR blockade promises to increase life expectancy through treatment and prevention of rheumatic diseases. PMID:26698023

  3. Inhibition of mTOR by Rapamycin Abolishes Cognitive Deficits and Reduces Amyloid-β Levels in a Mouse Model of Alzheimer's Disease

    PubMed Central

    Spilman, Patricia; Podlutskaya, Natalia; Hart, Matthew J.; Debnath, Jayanta; Gorostiza, Olivia; Bredesen, Dale; Richardson, Arlan; Strong, Randy; Galvan, Veronica

    2010-01-01

    Background Reduced TOR signaling has been shown to significantly increase lifespan in a variety of organisms [1], [2], [3], [4]. It was recently demonstrated that long-term treatment with rapamycin, an inhibitor of the mTOR pathway[5], or ablation of the mTOR target p70S6K[6] extends lifespan in mice, possibly by delaying aging. Whether inhibition of the mTOR pathway would delay or prevent age-associated disease such as AD remained to be determined. Methodology/Principal Findings We used rapamycin administration and behavioral tools in a mouse model of AD as well as standard biochemical and immunohistochemical measures in brain tissue to provide answers for this question. Here we show that long-term inhibition of mTOR by rapamycin prevented AD-like cognitive deficits and lowered levels of Aβ42, a major toxic species in AD[7], in the PDAPP transgenic mouse model. These data indicate that inhibition of the mTOR pathway can reduce Aβ42 levels in vivo and block or delay AD in mice. As expected from the inhibition of mTOR, autophagy was increased in neurons of rapamycin-treated transgenic, but not in non-transgenic, PDAPP mice, suggesting that the reduction in Aβ and the improvement in cognitive function are due in part to increased autophagy, possibly as a response to high levels of Aβ. Conclusions/Significance Our data suggest that inhibition of mTOR by rapamycin, an intervention that extends lifespan in mice, can slow or block AD progression in a transgenic mouse model of the disease. Rapamycin, already used in clinical settings, may be a potentially effective therapeutic agent for the treatment of AD. PMID:20376313

  4. Prevention

    MedlinePlus

    ... our e-newsletter! Aging & Health A to Z Prevention Basic Facts & Information Some factors that affect your ... control of the things that you can change. Preventive Recommendations for Adults Aged 65 and Older The ...

  5. Therapeutic mTOR inhibition in autosomal dominant polycystic kidney disease: What is the appropriate serum level?

    PubMed

    Canaud, G; Knebelmann, B; Harris, P C; Vrtovsnik, F; Correas, J-M; Pallet, N; Heyer, C M; Letavernier, E; Bienaimé, F; Thervet, E; Martinez, F; Terzi, F; Legendre, C

    2010-07-01

    Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited renal disease, and sirolimus, a mammalian target of rapamycin (mTOR) inhibitor, has been shown to significantly retard cyst expansion in animal models. The optimal therapeutic dose of sirolimus is not yet defined. Here, we report the history of a previously unknown ADPKD deceased donor whose kidneys were engrafted in two different recipients. One of the two received an immunosuppressive regimen based on sirolimus for 5 years while the other did not. After transplantation, both patients developed severe transplant cystic disease. Donor DNA sequence identified a new hypomorphic mutation in PKD1. The rate of cyst growth was identical in the two patients regardless of the treatment. While sirolimus treatment reduced the activation of mTOR in peripheral blood mononuclear cells, it failed to prevent mTOR activation in kidney tubular cells, this could account for the inefficiency of treatment on cyst growth. Together, our results suggest that the dose of sirolimus required to inhibit mTOR varies according to the tissue. PMID:20642692

  6. FXR blocks the growth of liver cancer cells through inhibiting mTOR-s6K pathway.

    PubMed

    Huang, Xiongfei; Zeng, Yeting; Wang, Xinrui; Ma, Xiaoxiao; Li, Qianqian; Li, Ningbo; Su, Hongying; Huang, Wendong

    2016-05-27

    The nuclear receptor Farnesoid X Receptor (FXR) is likely a tumor suppressor in liver tissue but its molecular mechanism of suppression is not well understood. In this study, the gene expression profile of human liver cancer cells was investigated by microarray. Bioinformatics analysis of these data revealed that FXR might regulate the mTOR/S6K signaling pathway. This was confirmed by altering the expression level of FXR in liver cancer cells. Overexpression of FXR prevented the growth of cells and induced cell cycle arrest, which was enhanced by the mTOR/S6K inhibitor rapamycin. FXR upregulation also intensified the inhibition of cell growth by rapamycin. Downregulation of FXR produced the opposite effect. Finally, we found that ectopic expression of FXR in SK-Hep-1 xenografts inhibits tumor growth and reduces expression of the phosphorylated protein S6K. Taken together, our data provide the first evidence that FXR suppresses proliferation of human liver cancer cells via the inhibition of the mTOR/S6K signaling pathway. FXR expression can be used as a biomarker of personalized mTOR inhibitor treatment assessment for liver cancer patients. PMID:27109477

  7. [mTOR, the mammalian target of rapamycin].

    PubMed

    Julien, Louis-André; Roux, Philippe P

    2010-12-01

    The discovery of rapamycin from a soil sample on Easter Island in the mid 60's marked the beginning of an exciting field of research in cell biology and medicine. While it was first used as an antifungal and as an immunosuppressive drug, more recent studies confirmed rapamycin's antiproliferative properties over a variety of solid tumors. Research aimed at identifying its mechanism of action uncovered mTOR (mammalian target of rapamycin), a protein kinase that regulates mRNA translation and protein synthesis, an essential step in cell division and proliferation. Recent evidence suggests a more complex role for mTOR in the regulation of several growth factor-stimulated protein kinases, including the proto-oncogene Akt. This article reviews mTOR function and regulation, and briefly details the future challenges for anti-cancer therapies based on mTOR inhibition. PMID:21187044

  8. Regulation of innate immune cell function by mTOR.

    PubMed

    Weichhart, Thomas; Hengstschläger, Markus; Linke, Monika

    2015-10-01

    The innate immune system is central for the maintenance of tissue homeostasis and quickly responds to local or systemic perturbations by pathogenic or sterile insults. This rapid response must be metabolically supported to allow cell migration and proliferation and to enable efficient production of cytokines and lipid mediators. This Review focuses on the role of mammalian target of rapamycin (mTOR) in controlling and shaping the effector responses of innate immune cells. mTOR reconfigures cellular metabolism and regulates translation, cytokine responses, antigen presentation, macrophage polarization and cell migration. The mTOR network emerges as an integrative rheostat that couples cellular activation to the environmental and intracellular nutritional status to dictate and optimize the inflammatory response. A detailed understanding of how mTOR metabolically coordinates effector responses by myeloid cells will provide important insights into immunity in health and disease. PMID:26403194

  9. mTOR Signaling from Cellular Senescence to Organismal Aging.

    PubMed

    Xu, Shaohua; Cai, Ying; Wei, Yuehua

    2014-08-01

    The TOR (target of rapamycin) pathway has been convincingly shown to promote aging in various model organisms. In mice, inhibiting mTOR (mammalian TOR) by rapamycin treatment later in life can significantly extend lifespan and mitigate multiple age-related diseases. However, the underlying mechanisms are poorly understood. Cellular senescence is strongly correlated to organismal aging therefore providing an attractive model to examine the mechanisms by which mTOR inhibition contributes to longevity and delaying the onset of related diseases. In this review, we examine the connections between mTOR and cellular senescence and discuss how understanding cellular senescence on the aspect of mTOR signaling may help to fully appreciate its role in the organismal aging. We also highlight the opposing roles of senescence in various human diseases and discuss the caveats in interpreting the emerging experimental data. PMID:25110610

  10. mTOR Inhibition: From Aging to Autism and Beyond

    PubMed Central

    2013-01-01

    The mechanistic target of rapamycin (mTOR) is a highly conserved protein that regulates growth and proliferation in response to environmental and hormonal cues. Broadly speaking, organisms are constantly faced with the challenge of interpreting their environment and making a decision between “grow or do not grow.” mTOR is a major component of the network that makes this decision at the cellular level and, to some extent, the tissue and organismal level as well. Although overly simplistic, this framework can be useful when considering the myriad functions ascribed to mTOR and the pleiotropic phenotypes associated with genetic or pharmacological modulation of mTOR signaling. In this review, I will consider mTOR function in this context and attempt to summarize and interpret the growing body of literature demonstrating interesting and varied effects of mTOR inhibitors. These include robust effects on a multitude of age-related parameters and pathologies, as well as several other processes not obviously linked to aging or age-related disease. PMID:24379984

  11. Effects of sotrastaurin, mycophenolic acid and everolimus on human B-lymphocyte function and activation.

    PubMed

    Matz, Mareen; Lehnert, Martin; Lorkowski, Christine; Fabritius, Katharina; Unterwalder, Nadine; Doueiri, Salim; Weber, Ulrike A; Mashreghi, Mir-Farzin; Neumayer, Hans-H; Budde, Klemens

    2012-10-01

    Humoral rejection processes may lead to allograft injury and subsequent dysfunction. Today, only one B-cell-specific agent is in clinical use and the effects of standard and new immunosuppressant substances on B-cell activation and function are not fully clarified. The impact of sotrastaurin, mycophenolic acid and everolimus on human B-lymphocyte function was assessed by analysing proliferation, apoptosis, CD80/CD86 expression and immunoglobulin and IL-10 production in primary stimulated B cells. In addition, B-cell co-cultures with pre-activated T cells were performed to evaluate the effect of the different immunosuppressive agents on T-cell-dependent immunoglobulin production. Sotrastaurin did not inhibit B-cell proliferation, CD80/CD86 expression, and IgG production and had only minor effects on IgM levels at the highest concentration administered. In contrast, mycophenolic acid and everolimus had strong effects on all B-cell functions in a dose-dependent manner. All immunosuppressive agents caused decreased immunoglobulin levels in T-cell-dependent B-cell cultures. The data provided here suggest that mycophenolic acid and everolimus, but not sotrastaurin, are potent inhibitors of human B-lymphocyte function and activation. PMID:22816666

  12. Evodiamine inhibits insulin-stimulated mTOR-S6K activation and IRS1 serine phosphorylation in adipocytes and improves glucose tolerance in obese/diabetic mice.

    PubMed

    Wang, Ting; Kusudo, Tatsuya; Takeuchi, Tamaki; Yamashita, Yukari; Kontani, Yasuhide; Okamatsu, Yuko; Saito, Masayuki; Mori, Nozomu; Yamashita, Hitoshi

    2013-01-01

    Evodiamine, an alkaloid extracted from the dried unripe fruit of the tree Evodia rutaecarpa Bentham (Rutaceae), reduces obesity and insulin resistance in obese/diabetic mice; however, the mechanism underlying the effect of evodiamine on insulin resistance is unknown. This study investigated the effect of evodiamine on signal transduction relating to insulin resistance using obese/diabetic KK-Ay mice and an in vitro adipocyte culture. There is a significant decrease in the mammalian target of rapamycin (mTOR) and ribosomal S6 protein kinase (S6K) signaling in white adipose tissue (WAT) in KK-Ay mice treated with evodiamine, in which glucose tolerance is improved. In addition, reduction of insulin receptor substrate 1 (IRS1) serine phosphorylation, an indicator of insulin resistance, was detected in their WAT, suggesting suppression of the negative feedback loop from S6K to IRS1. As well as the stimulation of IRS1 and Akt serine phosphorylation, insulin-stimulated phosphorylation of mTOR and S6K is time-dependent in 3T3-L1 adipocytes, whereas evodiamine does not affect their phosphorylation except for an inhibitory effect on mTOR phosphorylation. Moreover, evodiamine inhibits the insulin-stimulated phosphorylation of mTOR and S6K, leading to down-regulation of IRS1 serine phosphorylation in the adipocytes. Evodiamine also stimulates phosphorylation of AMP-activated protein kinase (AMPK), an important regulator of energy metabolism, which may cause down-regulation of mTOR signaling in adipocytes. A similar effect on AMPK, mTOR and IRS1 phosphorylation was found in adipocytes treated with rosiglitazone. These results suggest evodiamine improves glucose tolerance and prevents the progress of insulin resistance associated with obese/diabetic states, at least in part, through inhibition of mTOR-S6K signaling and IRS1 serine phosphorylation in adipocytes. PMID:24391749

  13. Akt-dependent and independent mechanisms of mTOR regulation in cancer

    PubMed Central

    Memmott, Regan M.; Dennis, Phillip A.

    2009-01-01

    The protein kinase mTOR (mammalian target of rapamycin) is a critical regulator of cellular metabolism, growth, and proliferation. These processes contribute to tumor formation, and many cancers are characterized by aberrant activation of mTOR. Although activating mutations in mTOR itself have not been identified, deregulation of upstream components that regulate mTOR are prevalent in cancer. The prototypic mechanism of mTOR regulation in cells is through activation of the PI3K/Akt pathway, but mTOR receives input from multiple signaling pathways. This review will discuss Akt-dependent and independent mechanisms of mTOR regulation in response to mitogenic signals, as well as its regulation in response to energy and nutrient-sensing pathways. Preclinical and clinical studies have demonstrated that tumors bearing genetic alterations that activate mTOR are sensitive to pharmacologic inhibition of mTOR. Elucidation of novel pathways that regulate mTOR may help identify predictive factors for sensitivity to mTOR inhibitors and could provide new therapeutic targets for inhibiting the mTOR pathway in cancer. This review will also highlight pharmacologic approaches that inhibit mTOR via activation of the AMP-activated protein kinase (AMPK), an important inhibitor of the mTOR pathway and an emerging target in cancer. PMID:19166931

  14. mTOR drives its own activation via SCFβ-TRCP-dependent degradation of the mTOR inhibitor DEPTOR

    PubMed Central

    Gao, Daming; Inuzuka, Hiroyuki; Tan, Meng-Kwang Marcus; Fukushima, Hidefumi; Locasale, Jason W.; Liu, Pengda; Wan, Lixin; Zhai, Bo; Chin, Y. Rebecca; Shaik, Shavali; Lyssiotis, Costas A.; Gygi, Steven P.; Toker, Alex; Cantley, Lewis C.; Asara, John M.; Harper, J. Wade; Wei, Wenyi

    2011-01-01

    Summary The activities of both mTORC1 and mTORC2 are negatively regulated by their endogenous inhibitor, DEPTOR. As such, the abundance of DEPTOR is a critical determinant in the activity status of the mTOR network. DEPTOR stability is governed by the 26S-proteasome through a largely unknown mechanism. Here we describe an mTOR-dependent phosphorylation-driven pathway for DEPTOR destruction via SCFβ-TRCP. DEPTOR phosphorylation by mTOR in response to growth signals, and in collaboration with casein kinase I (CKI), generates a phosphodegron that binds β-TRCP. Failure to degrade DEPTOR through either degron mutation or β-TRCP depletion leads to reduced mTOR activity, reduced S6 kinase activity, and activation of autophagy to reduce cell growth. This work expands the current understanding of mTOR regulation by revealing a positive feedback loop involving mTOR and CKI-dependent turnover of its inhibitor, DEPTOR, suggesting that misregulation of the DEPTOR destruction pathway might contribute to aberrant activation of mTOR in disease. PMID:22017875

  15. Fbxw7 Limits Myelination by Inhibiting mTOR Signaling

    PubMed Central

    Kearns, Christina A.; Ravanelli, Andrew M.; Cooper, Kirsten

    2015-01-01

    An important characteristic of vertebrate CNS development is the formation of specific amounts of insulating myelin membrane on axons. CNS myelin is produced by oligodendrocytes, glial cells that extend multiple membrane processes to wrap multiple axons. Recent data have shown that signaling mediated by the mechanistic target of rapamycin (mTOR) serine/threonine kinase promotes myelination, but factors that regulate mTOR activity for myelination remain poorly defined. Through a forward genetic screen in zebrafish, we discovered that mutation of fbxw7, which encodes the substrate recognition subunit of a SCF ubiquitin ligase that targets proteins for degradation, causes hypermyelination. Among known Fbxw7 targets is mTOR. Here, we provide evidence that mTOR signaling activity is elevated in oligodendrocyte lineage cells of fbxw7 mutant zebrafish larvae. Both genetic and pharmacological inhibition of mTOR function suppressed the excess myelin gene expression resulting from loss of Fbxw7 function, indicating that mTOR is a functionally relevant target of Fbxw7 in oligodendrocytes. fbxw7 mutant larvae wrapped axons with more myelin membrane than wild-type larvae and oligodendrocyte-specific expression of dominant-negative Fbxw7 produced longer myelin sheaths. Our data indicate that Fbxw7 limits the myelin-promoting activity of mTOR, thereby serving as an important brake on developmental myelination. SIGNIFICANCE STATEMENT Myelin, a specialized, proteolipid-rich membrane that ensheaths and insulates nerve fibers, facilitates the rapid conduction of electrical impulses over long distances. Abnormalities in myelin formation or maintenance result in intellectual and motor disabilities, raising a need for therapeutic strategies designed to promote myelination. The mTOR kinase is a powerful driver of myelination, but the mechanisms that regulate mTOR function in myelination are not well understood. Our studies reveal that Fbxw7, a subunit of a ubiquitin ligase that targets

  16. Early Response to Everolimus Therapy Detected on 68Ga-DOTATATE PET/CT in a Patient With Pancreatic Neuroendocrine Tumor.

    PubMed

    Ozkan, Elgin; Soydal, Cigdem; Ucak Semirgin, Sibel; Yapici, Oktay; Atmaca, Aysegul; Demirag, Guzin

    2016-07-01

    Everolimus is a mammalian target of rapamycin inhibitor that has been recently approved for the treatment of patients with advanced progressive pancreatic neuroendocrine tumor. Here, we present a case in which an early therapy response to everolimus was effectively demonstrated by Ga-DOTATATE PET/CT. PMID:27163457

  17. Talks about TORCs: recent advancesin target of rapamycin signalling. On mTOR nomenclature.

    PubMed

    Hall, Michael N

    2013-08-01

    In the present article, I discuss recent developments in the naming of the TOR (target of rapamycin) protein. In particular, I address the issue of mammalian target of rapamycin (mTOR) versus the newer mechanistic target of rapamycin (MTOR). mTOR is the name given by the TOR community almost two decades ago and widely used ever since. MTOR is a name recently imposed on the TOR community by database curators and used mainly by newcomers. I argue that MTOR is causing needless confusion in the field, and conclude that one should use the name mTOR. PMID:23863150

  18. Prevention

    MedlinePlus

    ... Prevention Treatment 2003 U.S. Outbreak African Rodent Importation Ban For Clinicians Clinical Recognition Specimen Collection Treatment Smallpox ... Examining Animals with Suspected Monkeypox African Rodent Importation Ban Resources Related Links Poxvirus Molluscum Contagiosum Orf Virus ( ...

  19. The Involvement of Mutual Inhibition of ERK and mTOR in PLCγ1-Mediated MMP-13 Expression in Human Osteoarthritis Chondrocytes

    PubMed Central

    Liu, Zejun; Cai, Heguo; Zheng, Xinpeng; Zhang, Bing; Xia, Chun

    2015-01-01

    The issue of whether ERK activation determines matrix synthesis or degradation in osteoarthritis (OA) pathogenesis currently remains controversial. Our previous study shows that PLCγ1 and mTOR are involved in the matrix metabolism of OA cartilage. Investigating the interplays of PLCγ1, mTOR and ERK in matrix degradation of OA will facilitate future attempts to manipulate ERK in OA prevention and therapy. Here, cultured human normal chondrocytes and OA chondrocytes were treated with different inhibitors or transfected with expression vectors, respectively. The levels of ERK, p-ERK, PLCγ1, p-PLCγ1, mTOR, p-mTOR and MMP-13 were then evaluated by Western blotting analysis. The results manifested that the expression level of ERK in human OA chondrocytes was lower than that in human normal articular chondrocytes, and the up-regulation of ERK could promote matrix synthesis, including the decrease in MMP-13 level and the increase in Aggrecan level in human OA chondrocytes. Furthermore, the PLCγ1/ERK axis and a mutual inhibition of mTOR and ERK were observed in human OA chondrocytes. Interestingly, activated ERK had no inhibitory effect on MMP-13 expression in PLCγ1-transformed OA chondrocytes. Combined with our previous study, the non-effective state of ERK activation by PLCγ1 on MMP-13 may be partly attributed to the inhibition of the PLCγ1/mTOR axis on the PLCγ1/ERK axis. Therefore, the study indicates that the mutual inhibition of ERK and mTOR is involved in PLCγ1-mediated MMP-13 expression in human OA chondrocytes, with important implication for the understanding of OA pathogenesis as well as for its prevention and therapy. PMID:26247939

  20. Three-year efficacy and safety results from a study of everolimus versus mycophenolate mofetil in de novo renal transplant patients.

    PubMed

    Vítko, Stefan; Margreiter, Raimund; Weimar, Willem; Dantal, Jacques; Kuypers, Dirk; Winkler, Michael; Øyen, Ole; Viljoen, Hendrik G; Filiptsev, Pavel; Sadek, Sami; Li, Yulan; Cretin, Nathalie; Budde, Klemens

    2005-10-01

    Everolimus 1.5 or 3 mg/day was compared with mycophenolate mofetil (MMF) 2 g/day in a randomized, multicenter 36-month trial in de novo renal allograft recipients (n = 588) receiving cyclosporine microemulsion (CsA) and corticosteroids. The study was double-blind until all patients had completed 12 months, then open-label. By 36 months, graft loss occurred in 7.2, 16.7 and 10.7% of patients in the everolimus 1.5, 3 mg/day, and MMF groups, respectively (p = 0.0048 for everolimus 1.5 mg/day vs. 3 mg/day); efficacy failure (biopsy-proven acute rejection (BPAR), graft loss, death or lost to follow-up) occurred in 33.0, 38.9 and 37.2% of patients (p = 0.455 overall), respectively. Mortality and incidence of BPAR were comparable in all groups. Creatinine values were higher in everolimus groups, requiring a protocol amendment that recommended lower CsA exposure. Diarrhea, lymphocele, peripheral edema and hyperlipidemia were more common among everolimus-treated patients, whereas viral infections, particularly cytomegalovirus infection, increased in the MMF group. Overall safety and tolerability were better with MMF and everolimus 1.5 mg/day than with everolimus 3 mg/day. In conclusion, at 36 months, an immunosuppressive regimen containing everolimus 1.5 mg/day had equivalent patient, and graft survival and rejection rates compared with MMF in de novo renal transplant recipients, whereas everolimus 3 mg/day had inferior graft survival. Renal dysfunction in everolimus cohorts necessitates close monitoring. PMID:16162203

  1. Brain somatic mutations in MTOR leading to focal cortical dysplasia.

    PubMed

    Lim, Jae Seok; Lee, Jeong Ho

    2016-02-01

    Focal cortical dysplasia type II (FCDII) is a focal malformation of the developing cerebral cortex and the major cause of intractable epilepsy. However, since the molecular genetic etiology of FCD has remained enigmatic, the effective therapeutic target for this condition has remained poorly understood. Our recent study on FCD utilizing various deep sequencing platforms identified somatic mutations in MTOR (existing as low as 1% allelic frequency) only in the affected brain tissues. We observed that these mutations induced hyperactivation of the mTOR kinase. In addition, focal cortical expression of mutant MTOR using in utero electroporation in mice, recapitulated the neuropathological features of FCDII, such as migration defect, cytomegalic neuron and spontaneous seizures. Furthermore, seizures and dysmorphic neurons were rescued by the administration of mTOR inhibitor, rapamycin. This study provides the first evidence that brain somatic activating mutations in MTOR cause FCD, and suggests the potential drug target for intractable epilepsy in FCD patients. [BMB Reports 2016; 49(2): 71-72]. PMID:26779999

  2. mTOR, cardiomyocytes and inflammation in cardiac hypertrophy.

    PubMed

    Xu, Lifen; Brink, Marijke

    2016-07-01

    Mammalian target of rapamycin (mTOR) is an evolutionary conserved kinase that senses the nutrient and energy status of cells, the availability of growth factors, stress stimuli and other cellular and environmental cues. It responds by regulating a range of cellular processes related to metabolism and growth in accordance with the available resources and intracellular needs. mTOR has distinct functions depending on its assembly in the structurally distinct multiprotein complexes mTORC1 or mTORC2. Active mTORC1 enhances processes including glycolysis, protein, lipid and nucleotide biosynthesis, and it inhibits autophagy. Reported functions for mTORC2 after growth factor stimulation are very diverse, are tissue and cell-type specific, and include insulin-stimulated glucose transport and enhanced glycogen synthesis. In accordance with its cellular functions, mTOR has been demonstrated to regulate cardiac growth in response to pressure overload and is also known to regulate cells of the immune system. The present manuscript presents recently obtained insights into mechanisms whereby mTOR may change anabolic, catabolic and stress response pathways in cardiomocytes and discusses how mTOR may affect inflammatory cells in the heart during hemodynamic stress. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel. PMID:26775585

  3. Targeting mTOR in Pancreatic Ductal Adenocarcinoma

    PubMed Central

    Iriana, Sentia; Ahmed, Shahzad; Gong, Jun; Annamalai, Alagappan Anand; Tuli, Richard; Hendifar, Andrew Eugene

    2016-01-01

    Treatment options for advanced pancreatic ductal adenocarcinoma (PDAC) are limited; however, new therapies targeting specific tumor-related molecular characteristics may help certain patient cohorts. Emerging preclinical data have shown that inhibition of mammalian target of rapamycin (mTOR) in specific KRAS-dependent PDAC subtypes leads to inhibition of tumorigenesis in vitro and in vivo. Early phase II studies of mono-mTOR inhibition have not shown promise. However, studies have shown that combined inhibition of multiple steps along the mTOR signaling pathway may lead to sustained responses by targeting mechanisms of tumor resistance. Coordinated inhibition of mTOR along with specific KRAS-dependent mutations in molecularly defined PDAC subpopulations may offer a viable alternative for treatment in the future. PMID:27200288

  4. mTOR: taking cues from the immune microenvironment

    PubMed Central

    Delgoffe, Greg M; Powell, Jonathan D

    2009-01-01

    The ultimate outcome of T cell receptor recognition is determined by the context in which the antigen is encountered. In this fashion both antigen-presenting cells and T cells must integrate multiple environmental cues in the form of pathogen-associated molecular patterns, cytokines and accessory molecule signals. The mammalian target of rapamycin (mTOR) is an evolutionarily conserved serine/threonine kinase that plays a central role in integrating environmental signals critical to regulating metabolism and cell survival. In this paper we review the data demonstrating that mTOR integrates signals from the immune microenvironment and therefore facilitates the generation of the adaptive immune response. Specifically, we review the role of mTOR in promoting dendritic cell activation and maturation, in regulating full T cell activation versus anergy, and influencing the induction of regulatory T cells. PMID:19604300

  5. Clinical development of mTOR inhibitors in breast cancer

    PubMed Central

    2014-01-01

    The mammalian target of rapamycin (mTOR) pathway is a central pathway that regulates mRNA translation, protein synthesis, glucose metabolism, lipid synthesis and autophagy, and is involved in malignant transformation. Several randomized trials have shown that the use of mTOR inhibitors could improve patient outcome with hormone receptor-positive or human epidermal growth factor receptor-2-positive breast cancer. This review analyzes new perspectives from these trials. Preclinical studies have suggested that the mTOR pathway may play a role in the resistance to hormone therapy, trastuzumab and chemotherapy for breast cancer. This concept has been tested in clinical trials for neoadjuvant treatment and for metastatic breast cancer patients. Also, much effort has gone into the identification of biomarkers that will allow for more precise stratification of patients. Findings from these studies will provide indispensable tools for the design of future clinical trials and identify new perspectives and challenges for researchers and clinicians. PMID:25189767

  6. Agmatine produces antidepressant-like effects by activating AMPA receptors and mTOR signaling.

    PubMed

    Neis, Vivian Binder; Moretti, Morgana; Bettio, Luis Eduardo B; Ribeiro, Camille M; Rosa, Priscila Batista; Gonçalves, Filipe Marques; Lopes, Mark William; Leal, Rodrigo Bainy; Rodrigues, Ana Lúcia S

    2016-06-01

    The activation of AMPA receptors and mTOR signaling has been reported as mechanisms underlying the antidepressant effects of fast-acting agents, specially the NMDA receptor antagonist ketamine. In the present study, oral administration of agmatine (0.1mg/kg), a neuromodulator that has been reported to modulate NMDA receptors, caused a significant reduction in the immobility time of mice submitted to the tail suspension test (TST), an effect prevented by the administration of DNQX (AMPA receptor antagonist, 2.5μg/site, i.c.v.), BDNF antibody (1μg/site, i.c.v.), K-252a (TrkB receptor antagonist, 1μg/site, i.c.v.), LY294002 (PI3K inhibitor, 10nmol/site, i.c.v.) or rapamycin (selective mTOR inhibitor, 0.2nmol/site, i.c.v.). Moreover, the administration of lithium chloride (non-selective GSK-3β inhibitor, 10mg/kg, p.o.) or AR-A014418 (selective GSK-3β inhibitor, 0.01μg/site, i.c.v.) in combination with a sub-effective dose of agmatine (0.0001mg/kg, p.o.) reduced the immobility time in the TST when compared with either drug alone. Furthermore, increased immunocontents of BDNF, PSD-95 and GluA1 were found in the prefrontal cortex of mice just 1h after agmatine administration. These results indicate that the antidepressant-like effect of agmatine in the TST may be dependent on the activation of AMPA and TrkB receptors, PI3K and mTOR signaling as well as inhibition of GSK-3β, and increase in synaptic proteins. The results contribute to elucidate the complex signaling pathways involved in the antidepressant effect of agmatine and reinforce the pivotal role of these molecular targets for antidepressant responses. PMID:27061850

  7. A Recollection of mTOR Signaling in Learning and Memory

    ERIC Educational Resources Information Center

    Graber, Tyson E.; McCamphill, Patrick K.; Sossin, Wayne S.

    2013-01-01

    Mechanistic target of rapamcyin (mTOR) is a central player in cell growth throughout the organism. However, mTOR takes on an additional, more specialized role in the developed neuron, where it regulates the protein synthesis-dependent, plastic changes underlying learning and memory. mTOR is sequestered in two multiprotein complexes (mTORC1 and…

  8. Everolimus and early calcineurin inhibitor withdrawal: 3-year results from a randomized trial in liver transplantation.

    PubMed

    Sterneck, M; Kaiser, G M; Heyne, N; Richter, N; Rauchfuss, F; Pascher, A; Schemmer, P; Fischer, L; Klein, C G; Nadalin, S; Lehner, F; Settmacher, U; Neuhaus, P; Gotthardt, D; Loss, M; Ladenburger, S; Paulus, E M; Mertens, M; Schlitt, H J

    2014-03-01

    The feasibility of de novo everolimus without calcineurin inhibitor (CNI) therapy following liver transplantation was assessed in a multicenter, prospective, open-label trial. Liver transplant patients were randomized at 4 weeks to start everolimus and discontinue CNI, or continue their current CNI-based regimen. The primary endpoint was adjusted estimated GFR (eGFR; Cockcroft-Gault) at month 11 post randomization. A 24-month extension phase followed 81/114 (71.1%) of eligible patients to month 35 post randomization. The adjusted mean eGFR benefit from randomization to month 35 was 10.1 mL/min (95% confidence interval [CI] -1.3, 21.5 mL/min, p = 0.082) in favor of CNI-free versus CNI using Cockcroft-Gault, 9.4 mL/min/1.73 m(2) (95% CI -0.4, 18.9, p = 0.053) with Modification of Diet in Renal Disease (four-variable) and 9.5 mL/min/1.73 m(2) (95% CI -1.1, 17.9, p = 0.028) using Nankivell. The difference in favor of the CNI-free regimen increased gradually over time due to a small progressive decline in eGFR in the CNI cohort despite a reduction in CNI exposure. Biopsy-proven acute rejection, graft loss and death were similar between groups. Adverse events led to study drug discontinuation in five CNI-free patients and five CNI patients (12.2% vs. 12.5%, p = 1.000) during the extension phase. Everolimus-based CNI-free immunosuppression is feasible following liver transplantation and patients benefit from sustained preservation of renal function versus patients on CNI for at least 3 years. PMID:24502384

  9. Everolimus and Early Calcineurin Inhibitor Withdrawal: 3-Year Results From a Randomized Trial in Liver Transplantation

    PubMed Central

    Sterneck, M; Kaiser, G M; Heyne, N; Richter, N; Rauchfuss, F; Pascher, A; Schemmer, P; Fischer, L; Klein, C G; Nadalin, S; Lehner, F; Settmacher, U; Neuhaus, P; Gotthardt, D; Loss, M; Ladenburger, S; Paulus, E M; Mertens, M; Schlitt, H J

    2014-01-01

    The feasibility of de novo everolimus without calcineurin inhibitor (CNI) therapy following liver transplantation was assessed in a multicenter, prospective, open-label trial. Liver transplant patients were randomized at 4 weeks to start everolimus and discontinue CNI, or continue their current CNI-based regimen. The primary endpoint was adjusted estimated GFR (eGFR; Cockcroft-Gault) at month 11 postrandomization. A 24-month extension phase followed 81/114 (71.1%) of eligible patients to month 35 postrandomization. The adjusted mean eGFR benefit from randomization to month 35 was 10.1 mL/min (95% confidence interval [CI] −1.3, 21.5 mL/min, p = 0.082) in favor of CNI-free versus CNI using Cockcroft-Gault, 9.4 mL/min/1.73 m2 (95% CI −0.4, 18.9, p = 0.053) with Modification of Diet in Renal Disease (four-variable) and 9.5 mL/min/1.73 m2 (95% CI −1.1, 17.9, p = 0.028) using Nankivell. The difference in favor of the CNI-free regimen increased gradually over time due to a small progressive decline in eGFR in the CNI cohort despite a reduction in CNI exposure. Biopsy-proven acute rejection, graft loss and death were similar between groups. Adverse events led to study drug discontinuation in five CNI-free patients and five CNI patients (12.2% vs. 12.5%, p = 1.000) during the extension phase. Everolimus-based CNI-free immunosuppression is feasible following liver transplantation and patients benefit from sustained preservation of renal function versus patients on CNI for at least 3 years. The beneficial effect on renal function achieved by early CNI withdrawal and treatment with everolimus after liver transplantation is still evident after three years. PMID:24502384

  10. Circulating biomarkers and outcome from a randomised phase II trial of sunitinib vs everolimus for patients with metastatic renal cell carcinoma

    PubMed Central

    Voss, Martin H; Chen, David; Marker, Mahtab; Hakimi, A Ari; Lee, Chung-Han; Hsieh, James J; Knox, Jennifer J; Voi, Maurizio; Motzer, Robert J

    2016-01-01

    Background: RECORD-3 assessed non-inferiority of progression-free survival (PFS) with everolimus vs sunitinib in previously untreated patients with metastatic renal cell carcinoma. Baseline plasma sample collection and randomised design enabled correlation of circulating biomarkers with efficacy. Methods: Samples were analysed for 121 cancer-related biomarkers. Analyses of biomarkers categorised patients as high or low (vs median) to assess association with first-line PFS (PFS1L) for each treatment arm. A composite biomarker score (CBS) incorporated biomarkers potentially predictive of PFS1L with everolimus. Results: Plasma samples from 442 of the 471 randomised patients were analysed. Biomarkers were associated with PFS1L for everolimus alone (29), sunitinib alone (9) or both (12). Everolimus-specific biomarkers (CSF1, ICAM1, IL-18BP, KIM1, TNFRII) with hazard ratio ⩾1.8 were integrated into a CBS (range 0–5). For CBS low (0–3, n=291) vs high (4–5, n=151), PFS1L differed significantly for everolimus but not for sunitinib. There was no significant difference in PFS1L between everolimus and sunitinib in the high CBS patient cohort. Conclusions: Baseline levels of multiple soluble biomarkers correlated with benefit from everolimus and/or sunitinib, independent of clinical risk factors. A similar PFS1L was observed for both treatments among patients with high CBS score. PMID:26908330

  11. Molecular mechanisms of mTOR regulation by stress

    PubMed Central

    Heberle, Alexander Martin; Prentzell, Mirja Tamara; van Eunen, Karen; Bakker, Barbara Marleen; Grellscheid, Sushma Nagaraja; Thedieck, Kathrin

    2015-01-01

    Tumors are prime examples of cell growth in unfavorable environments that elicit cellular stress. The high metabolic demand and insufficient vascularization of tumors cause a deficiency of oxygen and nutrients. Oncogenic mutations map to signaling events via mammalian target of rapamycin (mTOR), metabolic pathways, and mitochondrial function. These alterations have been linked with cellular stresses, in particular endoplasmic reticulum (ER) stress, hypoxia, and oxidative stress. Yet tumors survive these challenges and acquire highly energy-demanding traits, such as overgrowth and invasiveness. In this review we focus on stresses that occur in cancer cells and discuss them in the context of mTOR signaling. Of note, many tumor traits require mTOR complex 1 (mTORC1) activity, but mTORC1 hyperactivation eventually sensitizes cells to apoptosis. Thus, mTORC1 activity needs to be balanced in cancer cells. We provide an overview of the mechanisms contributing to mTOR regulation by stress and suggest a model wherein stress granules function as guardians of mTORC1 signaling, allowing cancer cells to escape stress-induced cell death. PMID:27308421

  12. mTOR in Brain Physiology and Pathologies.

    PubMed

    Bockaert, Joël; Marin, Philippe

    2015-10-01

    TOR (target of rapamycin) and its mammalian ortholog mTOR have been discovered in an effort to understand the mechanisms of action of the immunosuppressant drug rapamycin extracted from a bacterium of the Easter Island (Rapa Nui) soil. mTOR is a serine/threonine kinase found in two functionally distinct complexes, mTORC1 and mTORC2, which are differentially regulated by a great number of nutrients such as glucose and amino acids, energy (oxygen and ATP/AMP content), growth factors, hormones, and neurotransmitters. mTOR controls many basic cellular functions such as protein synthesis, energy metabolism, cell size, lipid metabolism, autophagy, mitochondria, and lysosome biogenesis. In addition, mTOR-controlled signaling pathways regulate many integrated physiological functions of the nervous system including neuronal development, synaptic plasticity, memory storage, and cognition. Thus it is not surprising that deregulation of mTOR signaling is associated with many neurological and psychiatric disorders. Preclinical and preliminary clinical studies indicate that inhibition of mTORC1 can be beneficial for some pathological conditions such as epilepsy, cognitive impairment, and brain tumors, whereas stimulation of mTORC1 (direct or indirect) can be beneficial for other pathologies such as depression or axonal growth and regeneration. PMID:26269525

  13. Leptin and mTOR: partners in metabolism and inflammation.

    PubMed

    Maya-Monteiro, Clarissa M; Bozza, Patricia T

    2008-06-15

    Leptin is both a hormone/cytokine that plays a major role in the regulation of feeding and energy expenditure. Beyond its central role in the hypothalamus, leptin modulates peripheral tissues' responses to growth and storage based on nutrient availability, and it regulates the innate and adaptive immune responses. mTOR (mammalian Target of Rapamycin) is a core component of intracellular signaling for cellular growth, mRNA translation, and metabolism. Here, we review recent findings on the cross talk between mTOR and leptin signaling. Important roles for mTOR on leptin signaling have been established both in hypothalamic centers to control food intake and in peripheral cells to regulate lipid metabolism and inflammation. Leptin directly activates resident macrophages to form ADRP-enriched lipid droplets and enhances eicosanoid production via a mechanism that is dependent on activation of the PI3K/mTOR pathway. Leptin-induced mTOR activation may have implications for obesity-related pathophysiological conditions such as diabetes, cardiovascular disease and cancer. PMID:18583936

  14. mTOR signaling pathway genes in focal epilepsies.

    PubMed

    Baulac, S

    2016-01-01

    Focal epilepsies, where seizures initiate in spatially limited networks, are the most frequent epilepsy type, accounting for two-thirds of patients. Focal epilepsies have long been thought to be acquired disorders; several focal epilepsy syndromes are now proven to be (genetically heterogeneous) monogenic disorders. While earlier genetic studies have demonstrated a strong contribution of ion channel and neurotransmitter receptor genes, or synaptic secreted protein genes, later work has revealed a new class of genes encoding components of the mechanistic target of rapamycin (mTOR) signal transduction pathway. The mTOR pathway controls a myriad of biological processes among which cell growth and protein synthesis in response to several extracellular and intracellular. Recently, germline mutations have been found in genes encoding the components of the GATOR1 complex (DEPDC5, NPRL2, NPRL3), a repressor of mTORC1. These mutations are increasingly recognized as causing a wide and yet evolving spectrum of focal epilepsy syndromes, with and without cortical structural abnormalities (usually focal cortical dysplasia). Brain somatic mutations in the gene encoding mTOR (MTOR) have recently been linked to focal cortical dysplasia and other associated brain pathologies including hemimegalencephaly. This chapter reviews the genetics and neurobiology of DEPDC5, NPRL2, and NPRL3, and summarizes the clinical and molecular spectrum of GATOR1-related epilepsies. PMID:27323939

  15. Adaptation to chronic mTOR inhibition in cancer and in aging.

    PubMed

    Gilley, Rebecca; Balmanno, Kathryn; Cope, Claire L; Cook, Simon J

    2013-08-01

    The mTOR [mammalian (or mechanistic) target of rapamycin] protein kinase co-ordinates catabolic and anabolic processes in response to growth factors and nutrients and is a validated anticancer drug target. Rapamycin and related allosteric inhibitors of mTORC1 (mTOR complex 1) have had some success in specific tumour types, but have not exhibited broad anticancer activity, prompting the development of new ATP-competitive mTOR kinase inhibitors that inhibit both mTORC1 and mTORC2. In common with other targeted kinase inhibitors, tumours are likely to adapt and acquire resistance to mTOR inhibitors. In the present article, we review studies that describe how tumour cells adapt to become resistant to mTOR inhibitors. mTOR is a central signalling hub which responds to an array of signalling inputs and activates a range of downstream effector pathways. Understanding how this signalling network is remodelled and which pathways are invoked to sustain survival and proliferation in the presence of mTOR inhibitors can provide new insights into the importance of the various mTOR effector pathways and may suggest targets for intervention to combine with mTOR inhibitors. Finally, since chronic mTOR inhibition by rapamycin can increase lifespan and healthspan in nematodes, fruitflies and mice, we contrast these studies with tumour cell responses to mTOR inhibition. PMID:23863163

  16. Differential requirement of mTOR in post-mitotic tissues and tumorigenesis

    PubMed Central

    Nardella, Caterina; Carracedo, Arkaitz; Alimonti, Andrea; Hobbs, Robin M.; Clohessy, John G.; Chen, Zhenbang; Egia, Ainara; Fornari, Alessandro; Fiorentino, Michelangelo; Loda, Massimo; Kozma, Sara C.; Thomas, George; Cordon-Cardo, Carlos; Pandolfi, Pier Paolo

    2010-01-01

    Summary The mammalian target of rapamycin (mTOR) is a crucial effector in a complex signaling network commonly disrupted in cancer. mTOR exerts its multiple functions in the context of two different multiprotein complexes: mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2). Loss of the tumor suppressor PTEN (phosphatase and tensin homolog deleted from chromosome 10) can hyperactivate mTOR through AKT and represents one of the most frequent events in human prostate cancer. We show here that conditional inactivation of mTor in the adult mouse prostate is seemingly inconsequential for this post-mitotic tissue. Conversely, inactivation of mTor leads to a marked suppression of Pten-loss-induced tumor initiation and progression in the prostate. This suppression is more pronounced than that elicited by the sole pharmacological abrogation of mTORC1. Acute inactivation of mTor in vitro also highlights the differential requirement of mTor function in proliferating and transformed cells. Collectively, our data constitute a strong rationale for developing specific mTOR kinase inhibitors targeting both mTORC1 and mTORC2 for the treatment of tumors triggered by PTEN deficiency and aberrant mTOR signaling. PMID:19176516

  17. Development and Validation of Stability-indicating High Performance Liquid Chromatographic Method for the Estimation of Everolimus in Tablets

    PubMed Central

    Sharmila, D.; Rao, A. Lakshmana; Kalyani, L.

    2015-01-01

    The present study depicts the development of a validated reversed-phase high performance liquid chromatographic method for the determination of the everolimus in presence of degradation products or pharmaceutical excipients. Stress study was performed on everolimus and it was found that it degrade sufficiently in oxidizing and acidic conditions but less degradation was found in alkaline, neutral, thermal and photolytic conditions. The separation was carried out on Hypersil BDS C18 column (100×4.6 mm, 5 μ) column having particle size 5 μ using acetate buffer:acetonitrile (50:50 v/v) with pH 6.5 adjusted with orthophosphoric acid as mobile phase at flow rate of 1 ml/min. The wavelength of the detection was 280 nm. A retention time (Rt) nearly 3.110 min was observed. The calibration curve for everolimus was linear (r2=0.999) from range of 25-150 μg/ml with limit of detection and limit of quantification of 0.036 μg/ml and 0.109 μg/ml, respectively. Analytical validation parameters such as selectivity, specificity, linearity, accuracy and precision were evaluated and relative standard deviation value for all the key parameters were less than 2.0%. The recovery of the drug after standard addition was found to be 100.55%. Thus, the developed RP-HPLC method was found to be suitable for the determination of everolimus in tablets containing various excipients. PMID:26798176

  18. Development and Validation of Stability-indicating High Performance Liquid Chromatographic Method for the Estimation of Everolimus in Tablets.

    PubMed

    Sharmila, D; Rao, A Lakshmana; Kalyani, L

    2015-01-01

    The present study depicts the development of a validated reversed-phase high performance liquid chromatographic method for the determination of the everolimus in presence of degradation products or pharmaceutical excipients. Stress study was performed on everolimus and it was found that it degrade sufficiently in oxidizing and acidic conditions but less degradation was found in alkaline, neutral, thermal and photolytic conditions. The separation was carried out on Hypersil BDS C18 column (100×4.6 mm, 5 μ) column having particle size 5 μ using acetate buffer:acetonitrile (50:50 v/v) with pH 6.5 adjusted with orthophosphoric acid as mobile phase at flow rate of 1 ml/min. The wavelength of the detection was 280 nm. A retention time (Rt) nearly 3.110 min was observed. The calibration curve for everolimus was linear (r(2)=0.999) from range of 25-150 μg/ml with limit of detection and limit of quantification of 0.036 μg/ml and 0.109 μg/ml, respectively. Analytical validation parameters such as selectivity, specificity, linearity, accuracy and precision were evaluated and relative standard deviation value for all the key parameters were less than 2.0%. The recovery of the drug after standard addition was found to be 100.55%. Thus, the developed RP-HPLC method was found to be suitable for the determination of everolimus in tablets containing various excipients. PMID:26798176

  19. Determination and validation of mTOR kinase-domain 3D structure by homology modeling

    PubMed Central

    Lakhlili, Wiame; Chevé, Gwénaël; Yasri, Abdelaziz; Ibrahimi, Azeddine

    2015-01-01

    The AKT/mammalian target of rapamycin (mTOR) pathway is considered as one of the commonly activated and deregulated signaling pathways in human cancer. mTOR is associated with other proteins in two molecular complexes: mTOR complex 1/Raptor and the mTOR complex 2/Rictor. Using the crystal structure of the related lipid kinase PI3Kγ, we built a model of the catalytic region of mTOR. The modeling of the three-dimensional (3D) structure of the mTOR was performed by homology modeling program SWISS-MODEL. The quality and validation of the obtained model were performed using PROCHECK and PROVE softwares. The overall stereochemical property of the protein was assessed by the Ramachandran plot. The model validation was also done by docking of known inhibitors. In this paper, we describe and validate a 3D model for the mTOR catalytic site. PMID:26257525

  20. Common corruption of the mTOR signaling network in human tumors.

    PubMed

    Menon, S; Manning, B D

    2008-12-01

    The mammalian target of rapamycin (mTOR) is responsive to numerous extracellular and intracellular cues and, through the formation of two physically and functionally distinct complexes, has a central role in the homeostatic control of cell growth, proliferation and survival. Through the aberrant activation of mTOR signaling, the perception of cellular growth signals becomes disconnected from the processes promoting cell growth, and this underlies the pathophysiology of a number of genetic tumor syndromes and cancers. Here, we review the oncogenes and tumor suppressors comprising the regulatory network upstream of mTOR, highlight the human cancers in which mTOR is activated and discuss how dysregulated mTOR signaling provides tumors a selective growth advantage. In addition, we discuss why activation of mTOR, as a consequence of distinct oncogenic events, results in diverse clinical outcomes, and how the complexity of the mTOR signaling network might dictate therapeutic approaches. PMID:19956179

  1. Common corruption of the mTOR signaling network in human tumors

    PubMed Central

    Menon, Suchithra; Manning, Brendan D.

    2013-01-01

    Summary The mammalian Target of Rapamycin (mTOR) is responsive to numerous extracellular and intracellular cues and, through the formation of two physically and functionally distinct complexes, plays a central role in the homeostatic control of cell growth, proliferation and survival. Through aberrant activation of mTOR signaling, the perception of cellular growth signals becomes disconnected from the processes promoting cell growth, and this underlies the pathophysiology of a number of genetic tumor syndromes and cancers. Here, we review the oncogenes and tumor suppressors comprising the regulatory network upstream of mTOR, highlight the human cancers in which mTOR is activated, and discuss how dysregulated mTOR signaling gives tumors a selective growth advantage. In addition, we discuss why activation of mTOR, as a consequence of distinct oncogenic events, results in diverse clinical outcomes, and how the complexity of the mTOR signaling network might dictate therapeutic approaches. PMID:19956179

  2. Additive Anti-Tumor Effects of Lovastatin and Everolimus In Vitro through Simultaneous Inhibition of Signaling Pathways

    PubMed Central

    Nölting, Svenja; Maurer, Julian; Spöttl, Gerald; Aristizabal Prada, Elke Tatjana; Reuther, Clemens; Young, Karen; Korbonits, Márta; Göke, Burkhard; Grossman, Ashley; Auernhammer, Christoph J.

    2015-01-01

    Background The mTORC1-inhibitor everolimus shows limited efficacy in treating patients with gastro-entero-pancreatic or pulmonary neuroendocrine tumors (NETs), and poor outcome in patients with malignant pheochromocytoma or hepatic carcinoma. We speculated that any effect may be enhanced by antogonising other signaling pathways. Methods Therefore, we tested the effect of lovastatin—known to inhibit both ERK and AKT signaling—and everolimus, separately and in combination, on cell viability and signaling pathways in human midgut (GOT), pancreatic (BON1), and pulmonary (H727) NET, hepatocellular carcinoma (HepG2, Huh7), and mouse pheochromocytoma (MPC, MTT) cell lines. Results Lovastatin and everolimus separately significantly reduced cell viability in H727, HepG2, Huh7, MPC and MTT cells at clinically relevant doses (P ≤ 0.05). However, high doses of lovastatin were necessary to affect GOT or BON1 cell viability. Clinically relevant doses of both drugs showed additive anti-tumor effects in H727, HepG2, Huh7, MPC and MTT cells (P ≤ 0.05), but not in BON1 or GOT cells. In all cell lines investigated, lovastatin inhibited EGFR and AKT signaling. Subsequently, combination treatment more strongly inhibited EGFR and AKT signaling than everolimus alone, or at least attenuated everolimus-induced EGFR or AKT activation. Vice versa, everolimus constantly decreased pp70S6K and combination treatment more strongly decreased pp70S6K than lovastatin alone, or attenuated lovastatin-induced p70S6K activation: in BON1 cells lovastatin-induced EGFR inhibition was least pronounced, possibly explaining the low efficacy and consequent absent additive effect. Conclusion In summary, clinically relevant doses of lovastatin and everolimus were effective separately and showed additive effects in 5 out of 7 cell lines. Our findings emphasize the importance of targeting several interacting signaling pathways simultaneously when attempting to attenuate tumor growth. However, the variable

  3. The inhibition of MAPK potentiates the anti-angiogenic efficacy of mTOR inhibitors

    SciTech Connect

    Dormond-Meuwly, Anne; Roulin, Didier; Dufour, Marc; Benoit, Michael; Demartines, Nicolas; Dormond, Olivier

    2011-04-22

    Highlights: {yields} Targeting mTOR in endothelial cell activates MAPK. {yields} Blocking MAPK enhances the anti-angiogenic effects of mTOR inhibitors. {yields} The anti-angiogenic efficacy of ATP-competitive inhibitors of mTOR is superior to that of rapamycin. -- Abstract: The mammalian target of rapamycin (mTOR) which is part of two functionally distinct complexes, mTORC1 and mTORC2, plays an important role in vascular endothelial cells. Indeed, the inhibition of mTOR with an allosteric inhibitor such as rapamycin reduces the growth of endothelial cell in vitro and inhibits angiogenesis in vivo. Recent studies have shown that blocking mTOR results in the activation of other prosurvival signals such as Akt or MAPK which counteract the growth inhibitory properties of mTOR inhibitors. However, little is known about the interactions between mTOR and MAPK in endothelial cells and their relevance to angiogenesis. Here we found that blocking mTOR with ATP-competitive inhibitors of mTOR or with rapamycin induced the activation of the mitogen-activated protein kinase (MAPK) in endothelial cells. Downregulation of mTORC1 but not mTORC2 had similar effects showing that the inhibition of mTORC1 is responsible for the activation of MAPK. Treatment of endothelial cells with mTOR inhibitors in combination with MAPK inhibitors reduced endothelial cell survival, proliferation, migration and tube formation more significantly than either inhibition alone. Similarly, in a tumor xenograft model, the anti-angiogenic efficacy of mTOR inhibitors was enhanced by the pharmacological blockade of MAPK. Taken together these results show that blocking mTORC1 in endothelial cells activates MAPK and that a combined inhibition of MAPK and mTOR has additive anti-angiogenic effects. They also provide a rationale to target both mTOR and MAPK simultaneously in anti-angiogenic treatment.

  4. mTOR is necessary for proper satellite cell activity and skeletal muscle regeneration

    SciTech Connect

    Zhang, Pengpeng; Liang, Xinrong; Shan, Tizhong; Jiang, Qinyang; Deng, Changyan; Zheng, Rong; Kuang, Shihuan

    2015-07-17

    The serine/threonine kinase mammalian target of rapamycin (mTOR) is a key regulator of protein synthesis, cell proliferation and energy metabolism. As constitutive deletion of Mtor gene results in embryonic lethality, the function of mTOR in muscle stem cells (satellite cells) and skeletal muscle regeneration remains to be determined. In this study, we established a satellite cell specific Mtor conditional knockout (cKO) mouse model by crossing Pax7{sup CreER} and Mtor{sup flox/flox} mice. Skeletal muscle regeneration after injury was severely compromised in the absence of Mtor, indicated by increased number of necrotic myofibers infiltrated by Evans blue dye, and reduced number and size of regenerated myofibers in the Mtor cKO mice compared to wild type (WT) littermates. To dissect the cellular mechanism, we analyzed satellite cell-derived primary myoblasts grown on single myofibers or adhered to culture plates. The Mtor cKO myoblasts exhibited defective proliferation and differentiation kinetics when compared to myoblasts derived from WT littermates. At the mRNA and protein levels, the Mtor cKO myoblasts expressed lower levels of key myogenic determinant genes Pax7, Myf5, Myod, Myog than did the WT myoblasts. These results suggest that mTOR is essential for satellite cell function and skeletal muscle regeneration through controlling the expression of myogenic genes. - Highlights: • Pax7{sup CreER} was used to delete Mtor gene in satellite cells. • Satellite cell specific deletion of Mtor impairs muscle regeneration. • mTOR is necessary for satellite cell proliferation and differentiation. • Deletion of Mtor leads to reduced expression of key myogenic genes.

  5. A phase I/II trial of BNC105P with everolimus in metastatic renal cell carcinoma (mRCC)

    PubMed Central

    Pal, Sumanta; Azad, Arun; Bhatia, Shailender; Drabkin, Harry; Costello, Brian; Sarantopoulos, John; Kanesvaran, Ravindran; Lauer, Richard; Starodub, Alexander; Hauke, Ralph; Sweeney, Christopher J.; Hahn, Noah M.; Sonpavde, Guru; Richey, Stephen; Breen, Timothy; Kremmidiotis, Gabriel; Leske, Annabell; Doolin, Elizabeth; Bibby, David C.; Simpson, Jeremy; Iglesias, Jose; Hutson, Thomas

    2015-01-01

    Purpose BNC105P inhibits tubulin polymerization, and preclinical studies suggest possible synergy with everolimus. In this phase I/II study, efficacy and safety of the combination were explored in patients with metastatic renal cell carcinoma (mRCC). Experimental Design A phase I study in patients with clear cell mRCC and any prior number of therapies was conducted using a classical 3+3 design to evaluate standard doses of everolimus with increasing doses of BNC105P. At the recommended phase II dose (RP2D), patients with clear cell mRCC and 1-2 prior therapies (including ≥1 VEGF-TKI) were randomized to BNC105P with everolimus (Arm A) or everolimus alone (Arm B). The primary endpoint of the study was 6-month progression-free survival (6MPFS). Secondary endpoints included response rate, PFS, overall survival (OS) and exploratory biomarker analyses. Results In the phase I study (n=15), a dose of BNC105P at 16 mg/m2 with everolimus at 10 mg daily was identified as the RP2D. In the phase II study, 139 patients were randomized, with 69 and 67 evaluable patients in Arms A and B, respectively. 6MPFS was similar in the treatment arms (Arm A: 33.82% v Arm B: 30.30%, P=0.66) and no difference in median PFS was observed (Arm A: 4.7 mos v Arm B: 4.1 mos; P=0.49). Changes in matrix metalloproteinase-9, stem cell factor, sex hormone binding globulin and serum amyloid A protein were associated with clinical outcome with BNC105P. Conclusions Although the primary endpoint was not met in an unselected population, correlative studies suggest several biomarkers that warrant further prospective evaluation. PMID:25788492

  6. Activity of everolimus (RAD001) in relapsed and/or refractory multiple myeloma: a phase I study

    PubMed Central

    Günther, Andreas; Baumann, Philipp; Burger, Renate; Kellner, Christian; Klapper, Wolfram; Schmidmaier, Ralf; Gramatzki, Martin

    2015-01-01

    The mammalian target of rapamycin plays an important role in multiple myeloma. The allosteric mammalian target of rapamycin inhibitor everolimus has long been approved for immunosuppression and has shown activity in certain cancers. This investigator-initiated phase I trial explored the use of everolimus in relapsed and/or refractory multiple myeloma patients who had received two or more lines of prior treatment. Following a dose-escalation design, it called for a fixed dose of oral everolimus. Blood drug levels were monitored and the biological activity of everolimus was evaluated in bone marrow. Seventeen patients were enrolled (age range, 52 to 76 years). All had been previously treated with stem cell transplantation and proteasome inhibitors and almost all with immunomodulatory drugs. No dose-limiting toxicity was observed and the intended final daily dose of 10 mg was reached. Only one severe adverse event was assessed as possibly related to the study drug, namely atypical pneumonia. Remarkably few infections were observed. Although the trial was mainly designed to evaluate feasibility, anti-myeloma activity, defined as clinical benefit, was documented in ten of 15 evaluable patients at every dose level including eight patients with stable disease, one patient with minor remission and one with partial remission. However, the median time to progression was 90 days (range, 13 to 278 days). The biomarker study documented on-target activity of everolimus in malignant plasma cells as well as the microenvironment. The observed responses are promising and allow further studies to be considered, including those testing combination strategies addressing escape pathways. This trial is registered with EudraCT number 2006-002675-41. PMID:25682600

  7. Everolimus for the treatment of subependymal giant cell astrocytoma probably causing seizure aggravation in a child with tuberous sclerosis complex: a case report.

    PubMed

    Wiemer-Kruel, Adelheid; Woerle, H; Strobl, K; Bast, T

    2014-04-01

    We are reporting on a 13.5-year-old girl with tuberous sclerosis complex (TSC) who was treated with everolimus because of giant cell astrocytoma and bilateral angiomyolipoma. She suffered from pharmacoresistant partial epilepsy with clusters of tonic and tonic-clonic seizures. Treatment with carbamazepine and sulthiame had led to a stable situation for more than 2.5 years. The dosage of everolimus had to be increased and refractory status epilepticus followed after 12 days. In the absence of any other possible cause, we believe that the status epilepticus was provoked by everolimus. So far, only a few cases of possible seizure aggravation by everolimus have been reported. The clinical relevance of possible negative effects in epileptic patients remains unclear. Similar observations should be documented and reported. PMID:24293099

  8. Oral Everolimus for Treatment of a Giant Left Ventricular Rhabdomyoma in a Neonate-Rapid Tumor Regression Documented by Real Time 3D Echocardiography.

    PubMed

    Wagner, Robert; Riede, Frank Thomas; Seki, Hiroshi; Hornemann, Frauke; Syrbe, Steffen; Daehnert, Ingo; Weidenbach, Michael

    2015-12-01

    The presented case reports on successful treatment with everolimus in a neonate with left ventricular giant rhabdomyoma. The authors used a different dosage regime compared to literature and documented rapid tumor regression by 3D echocardiography. PMID:26199144

  9. Dual-Blocking of PI3K and mTOR Improves Chemotherapeutic Effects on SW620 Human Colorectal Cancer Stem Cells by Inducing Differentiation.

    PubMed

    Kim, Min-Jung; Koo, Jeong-Eun; Han, Gi-Yeon; Kim, Buyun; Lee, Yoo-Sun; Ahn, Chiyoung; Kim, Chan-Wha

    2016-03-01

    Cancer stem cells (CSCs) have tumor initiation, self-renewal, metastasis and chemo-resistance properties in various tumors including colorectal cancer. Targeting of CSCs may be essential to prevent relapse of tumors after chemotherapy. Phosphatidylinositol-3-kinase (PI3K) and mammalian target of rapamycin (mTOR) signals are central regulators of cell growth, proliferation, differentiation, and apoptosis. These pathways are related to colorectal tumorigenesis. This study focused on PI3K and mTOR pathways by inhibition which initiate differentiation of SW620 derived CSCs and investigated its effect on tumor progression. By using rapamycin, LY294002, and NVP-BEZ235, respectively, PI3K and mTOR signals were blocked independently or dually in colorectal CSCs. Colorectal CSCs gained their differentiation property and lost their stemness properties most significantly in dual-blocked CSCs. After treated with anti-cancer drug (paclitaxel) on the differentiated CSCs cell viability, self-renewal ability and differentiation status were analyzed. As a result dual-blocking group has most enhanced sensitivity for anti-cancer drug. Xenograft tumorigenesis assay by using immunodeficiency mice also shows that dual-inhibited group more effectively increased drug sensitivity and suppressed tumor growth compared to single-inhibited groups. Therefore it could have potent anti-cancer effects that dual-blocking of PI3K and mTOR induces differentiation and improves chemotherapeutic effects on SW620 human colorectal CSCs. PMID:26955235

  10. Dual-Blocking of PI3K and mTOR Improves Chemotherapeutic Effects on SW620 Human Colorectal Cancer Stem Cells by Inducing Differentiation

    PubMed Central

    Kim, Buyun

    2016-01-01

    Cancer stem cells (CSCs) have tumor initiation, self-renewal, metastasis and chemo-resistance properties in various tumors including colorectal cancer. Targeting of CSCs may be essential to prevent relapse of tumors after chemotherapy. Phosphatidylinositol-3-kinase (PI3K) and mammalian target of rapamycin (mTOR) signals are central regulators of cell growth, proliferation, differentiation, and apoptosis. These pathways are related to colorectal tumorigenesis. This study focused on PI3K and mTOR pathways by inhibition which initiate differentiation of SW620 derived CSCs and investigated its effect on tumor progression. By using rapamycin, LY294002, and NVP-BEZ235, respectively, PI3K and mTOR signals were blocked independently or dually in colorectal CSCs. Colorectal CSCs gained their differentiation property and lost their stemness properties most significantly in dual-blocked CSCs. After treated with anti-cancer drug (paclitaxel) on the differentiated CSCs cell viability, self-renewal ability and differentiation status were analyzed. As a result dual-blocking group has most enhanced sensitivity for anti-cancer drug. Xenograft tumorigenesis assay by using immunodeficiency mice also shows that dual-inhibited group more effectively increased drug sensitivity and suppressed tumor growth compared to single-inhibited groups. Therefore it could have potent anti-cancer effects that dual-blocking of PI3K and mTOR induces differentiation and improves chemotherapeutic effects on SW620 human colorectal CSCs. PMID:26955235

  11. Comparative effectiveness of everolimus and axitinib as second targeted therapies for metastatic renal cell carcinoma in the US: a retrospective chart review.

    PubMed

    Vogelzang, Nicholas J; Pal, Sumanta K; Signorovitch, James E; Reichmann, William M; Li, Nanxin; Yang, Chelsey; Liu, Zhimei; Perez, Jose Ricardo; Jonasch, Eric

    2016-01-01

    Background Second targeted therapies for metastatic renal cell carcinoma (mRCC) include mammalian target of rapamycin inhibitors (mTORis) and tyrosine kinase inhibitors (TKIs). This observational study compares overall survival (OS) and progression-free survival (PFS) of patients treated with everolimus (an mTORi) and axitinib (a TKI) following first TKI, and assesses the impact of type and duration of first TKI on the relative effectiveness of these second targeted therapies. Methods Retrospective reviews of medical records were conducted by medical oncologists or hematologists/oncologists recruited from a nationwide panel. Included patients with mRCC were required to have discontinued a first TKI (sunitinib, sorafenib, or pazopanib) for medical reasons, and to have initiated everolimus or axitinib as second targeted therapy between February 2012 and January 2013. OS and PFS were compared between patients treated with everolimus vs. axitinib using multivariable Cox proportional hazards regression models. Comparative results were also stratified by type and duration of first TKI. Results Included patients (n = 325 for everolimus and n = 127 for axitinib) had a mean age of 61 years and 31% were female. Sunitinib was the most commonly used first TKI (73%). After adjusting for patient characteristics, no statistically significant differences were observed in OS or PFS between everolimus and axitinib. When stratifying by type and duration of first TKI, there was no statistically significant difference in OS between everolimus and axitinib in all subgroups except for patients with <6 months on sunitinib or sorafenib as first TKI. No significant difference in PFS was observed in any subgroup. Limitations Important limitations include potential missing or inaccurate data in medical charts, and confounding due to unobserved factors. Conclusions In this retrospective chart review, no significant differences were detected in OS or PFS between axitinib and

  12. mTOR Enhances Foam Cell Formation by Suppressing the Autophagy Pathway

    PubMed Central

    Li, Lingxia; Niu, Xiaolin; Dang, Xiaoyan; Li, Ping; Qu, Li; Bi, Xiaoju; Gao, Yanxia; Hu, Yanfen; Li, Manxiang; Qiao, Wanhai; Peng, Zhuo; Pan, Longfei

    2014-01-01

    Recently, autophagy has drawn more attention in cardiovascular disease as it has important roles in lipid metabolism. Mammalian target of rapamycin (mTOR) is a key regulator of autophagy; however, its effect on atherosclerosis and the underlying mechanism remains undefined. In this study, an obvious upregulation of mTOR and p-mTOR protein was observed in macrophage-derived foam cells. Blocking mTOR expression with specific small interference RNA (siRNA) dramatically suppressed foam cell formation, accompanied by a decrease of lipid deposition. Further mechanistic analysis indicated that suppressing mTOR expression significantly upregulated autophagic marker LC3 expression and downregulated autophagy substrate p62 levels, indicating that mTOR silencing triggered autophagosome formation. Moreover, blocking mTOR expression obviously accelerated neutral lipid delivery to lysosome and cholesterol efflux from foam cells, implying that mTOR could induce macrophage foam cell formation by suppressing autophagic pathway. Further, mTOR silencing significantly upregulated ULK1 expression, which was accounted for mTOR-induced foam cell formation via autophagic pathway as treatment with ULK1 siRNA dampened LC3-II levels and increased p62 expression, concomitant with lipid accumulation and decreased cholesterol efflux from foam cells. Together, our data provide an insight into how mTOR accelerates the pathological process of atherosclerosis. Accordingly, blocking mTOR levels may be a promising therapeutic agent against atherosclerotic complications. PMID:24512183

  13. mTOR signaling in osteosarcoma: Oncogenesis and therapeutic aspects (Review).

    PubMed

    Hu, Kai; Dai, Hai-Bo; Qiu, Zhi-Long

    2016-09-01

    The mammalian target of rapamycin (mTOR) is a serine/threonine protein kinase that belongs to the phosphoinositide-3-kinase (PI3K)-related kinase family. Oncogenic activation of mTOR signaling significantly contributes to the progression of different types of cancers including osteosarcoma (OS; the most common primary malignant tumor of bone). In the present study, we review the association of the mTOR signaling pathway with OS, and the possible effective treatment strategies by targeting this pathway. In the metastatic behavior of OS, one of the most common actionable aberrations was found in the PI3K/Akt/mTOR pathway. Upon phosphorylation, activated mTOR contributes to OS cellular transformation and poor cancer prognosis via downstream effectors such as S6K1, 4EBP1 and eIF4E, which are overexpressed in OS. Targeting the mTOR complex is a significant approach in cancer therapeutic research, and of course, rapamycin is the primary inhibitor of mTOR. Various other chemotherapeutic molecules have also shown potential activity against mTOR. As mTOR is a new promising oncological target and blockade of the mTOR pathway with selective inhibitors has significant potential in OS therapeutic research, the development of the optimal dose, regimen and a rationale for the use of mTOR inhibitors in combination with other anticancer agents may provide a successful treatment strategy for OS. PMID:27430283

  14. Intersection of mTOR and STAT signaling in immunity

    PubMed Central

    Saleiro, Diana; Platanias, Leonidas C.

    2014-01-01

    Optimal regulation of immune networks is essential for generation of effective immune responses, and defects in such networks can lead to immunodeficiency, while uncontrolled responses can result in autoimmune disorders. mTOR and STAT signaling cascades are key regulators of differentiation and function of cells of the immune system. Both pathways act as sensors and transducers of environmental stimuli, and recent evidence has revealed points of crosstalk between these pathways, highlighting synergistic regulation of immune cell differentiation and function. Here we review the current understanding of mTOR and STAT interactions in T cells and innate immune cells, and discuss potential mechanisms underlying these events. We further outline models for the intersection of these pathways in the regulation of immunity, and highlight important areas for future research. PMID:25592035

  15. Frontier of Epilepsy Research - mTOR signaling pathway

    PubMed Central

    2011-01-01

    Studies of epilepsy have mainly focused on the membrane proteins that control neuronal excitability. Recently, attention has been shifting to intracellular proteins and their interactions, signaling cascades and feedback regulation as they relate to epilepsy. The mTOR (mammalian target of rapamycin) signal transduction pathway, especially, has been suggested to play an important role in this regard. These pathways are involved in major physiological processes as well as in numerous pathological conditions. Here, involvement of the mTOR pathway in epilepsy will be reviewed by presenting; an overview of the pathway, a brief description of key signaling molecules, a summary of independent reports and possible implications of abnormalities of those molecules in epilepsy, a discussion of the lack of experimental data, and questions raised for the understanding its epileptogenic mechanism. PMID:21467839

  16. Everolimus-eluting stent platforms in percutaneous coronary intervention: comparative effectiveness and outcomes.

    PubMed

    Panoulas, Vasileios F; Mastoris, Ioannis; Konstantinou, Klio; Tespili, Maurizio; Ielasi, Alfonso

    2015-01-01

    Despite the remarkable benefits obtained following the introduction of the first-generation drug-eluting stent (DES), concerns were raised over its long-term safety, particularly with regard to very late (beyond 1 year) stent thrombosis. Newer-generation DESs have been developed to overcome this limitation using novel stent platforms, new drugs, more biocompatible durable polymers, and bioabsorbable polymers or backbones. To date, new-generation DESs have virtually replaced the use of first-generation DESs worldwide. In this review article, we discuss in detail the design, pharmacology, and mechanism of action of the newer-generation permanent and bioresorbable everolimus-eluting platforms. Furthermore, we present and evaluate the current evidence on the performance and safety of these devices compared to those of other available stent platforms. PMID:26244031

  17. Multiple Stent Fractures After Everolimus-Eluting Stent Implantation Causing Acute Myocardial Infarction

    PubMed Central

    Ji, Eun Young; Park, Gyung-Min; Kim, Dae Won; Kim, Tae-Seok; Kim, Chan Joon; Cho, Jung Sun; Park, Mahn-Won; Her, Sung Ho

    2016-01-01

    Abstract Stent fracture is an uncommon complication of drug-eluting stent implantation, but it has a clinical significance because of its potential association with adverse cardiac events such as in-stent restenosis, target lesion revascularization, and stent thrombosis. Multiple stent fractures account for a small proportion, but they may lead to more serious complications. Newer generation drug-eluting stents are designed for improved safety and efficacy compared with early generation drug-eluting stents. Multiple stent fractures after newer generation drug-eluting stent implantation are a rare case. We report a case of 25-year-old male who presented with acute myocardial infarction caused by multiple stent fractures after everolimus-eluting stents implantation and was treated by balloon angioplasty. Physicians should be aware of the possibility of multiple stent fractures even after newer generation drug-eluting stent implantation. PMID:26871806

  18. Second generation drug-eluting stents: a review of the everolimus-eluting platform.

    PubMed

    Whitbeck, Matthew G; Applegate, Robert J

    2013-01-01

    Everolimus-eluting stents (EES) represent the next generation of drug-eluting stents (DES). Important design modifications include thin strut stent backbones, less inflammatory and more biocompatible polymers, and lower drug dosing. The cobalt chromium EES fluoropolymer XIENCE V stent has been the most extensively studied of such stents. In animal models, this stent demonstrated minimal vessel inflammation, a biologically active endothelium with strut coverage similar to a bare metal stent, and inhibition of intimal hyperplasia comparable to that seen with sirolimus-eluting stents. The SPIRIT family of clinical trials demonstrated low rates of late loss, and clinical restenosis, as well as low rates of very late stent thrombosis. These excellent clinical outcomes addressed limitations of the 1st generation DES, and substantiated widespread clinical use of the EES platform. PMID:23926441

  19. Everolimus-eluting stent platforms in percutaneous coronary intervention: comparative effectiveness and outcomes

    PubMed Central

    Panoulas, Vasileios F; Mastoris, Ioannis; Konstantinou, Klio; Tespili, Maurizio; Ielasi, Alfonso

    2015-01-01

    Despite the remarkable benefits obtained following the introduction of the first-generation drug-eluting stent (DES), concerns were raised over its long-term safety, particularly with regard to very late (beyond 1 year) stent thrombosis. Newer-generation DESs have been developed to overcome this limitation using novel stent platforms, new drugs, more biocompatible durable polymers, and bioabsorbable polymers or backbones. To date, new-generation DESs have virtually replaced the use of first-generation DESs worldwide. In this review article, we discuss in detail the design, pharmacology, and mechanism of action of the newer-generation permanent and bioresorbable everolimus-eluting platforms. Furthermore, we present and evaluate the current evidence on the performance and safety of these devices compared to those of other available stent platforms. PMID:26244031

  20. Mechanistic Target of Rapamycin (Mtor) Is Essential for Murine Embryonic Heart Development and Growth

    PubMed Central

    Zhu, Yi; Pires, Karla M. P.; Whitehead, Kevin J.; Olsen, Curtis D.; Wayment, Benjamin; Zhang, Yi Cheng; Bugger, Heiko; Ilkun, Olesya; Litwin, Sheldon E.; Thomas, George; Kozma, Sara C.; Abel, E. Dale

    2013-01-01

    Mechanistic target of rapamycin (Mtor) is required for embryonic inner cell mass proliferation during early development. However, Mtor expression levels are very low in the mouse heart during embryogenesis. To determine if Mtor plays a role during mouse cardiac development, cardiomyocyte specific Mtor deletion was achieved using α myosin heavy chain (α-MHC) driven Cre recombinase. Initial mosaic expression of Cre between embryonic day (E) 10.5 and E11.5 eliminated a subset of cardiomyocytes with high Cre activity by apoptosis and reduced overall cardiac proliferative capacity. The remaining cardiomyocytes proliferated and expanded normally. However loss of 50% of cardiomyocytes defined a threshold that impairs the ability of the embryonic heart to sustain the embryo’s circulatory requirements. As a result 92% of embryos with cardiomyocyte Mtor deficiency died by the end of gestation. Thus Mtor is required for survival and proliferation of cardiomyocytes in the developing heart. PMID:23342106

  1. Crosstalk between Ca2+ signaling and mitochondrial H2O2 is required for rotenone inhibition of mTOR signaling pathway leading to neuronal apoptosis

    PubMed Central

    Zhou, Qian; Zhang, Ruijie; Zhang, Hai; Liu, Wen; Xu, Chong; Liu, Lei; Huang, Shile; Chen, Long

    2016-01-01

    Rotenone, a neurotoxic pesticide, induces loss of dopaminergic neurons related to Parkinson's disease. Previous studies have shown that rotenone induces neuronal apoptosis partly by triggering hydrogen peroxide (H2O2)-dependent suppression of mTOR pathway. However, the underlying mechanism is not fully understood. Here, we show that rotenone elevates intracellular free calcium ion ([Ca2+]i) level, and activates CaMKII, resulting in inhibition of mTOR signaling and induction of neuronal apoptosis. Chelating [Ca2+]i with BAPTA/AM, preventing extracellular Ca2+ influx using EGTA, inhibiting CaMKII with KN93, or silencing CaMKII significantly attenuated rotenone-induced H2O2 production, mTOR inhibition, and cell death. Interestingly, using TTFA, antimycin A, catalase or Mito-TEMPO, we found that rotenone-induced mitochondrial H2O2 also in turn elevated [Ca2+]i level, thereby stimulating CaMKII, leading to inhibition of mTOR pathway and induction of neuronal apoptosis. Expression of wild type mTOR or constitutively active S6K1, or silencing 4E-BP1 strengthened the inhibitory effects of catalase, Mito-TEMPO, BAPTA/AM or EGTA on rotenone-induced [Ca2+]i elevation, CaMKII phosphorylation and neuronal apoptosis. Together, the results indicate that the crosstalk between Ca2+ signaling and mitochondrial H2O2 is required for rotenone inhibition of mTOR-mediated S6K1 and 4E-BP1 pathways. Our findings suggest that how to control over-elevation of intracellular Ca2+ and overproduction of mitochondrial H2O2 may be a new approach to deal with the neurotoxicity of rotenone. PMID:26859572

  2. Crosstalk between Ca2+ signaling and mitochondrial H2O2 is required for rotenone inhibition of mTOR signaling pathway leading to neuronal apoptosis.

    PubMed

    Liu, Chunxiao; Ye, Yangjing; Zhou, Qian; Zhang, Ruijie; Zhang, Hai; Liu, Wen; Xu, Chong; Liu, Lei; Huang, Shile; Chen, Long

    2016-02-16

    Rotenone, a neurotoxic pesticide, induces loss of dopaminergic neurons related to Parkinson's disease. Previous studies have shown that rotenone induces neuronal apoptosis partly by triggering hydrogen peroxide (H2O2)-dependent suppression of mTOR pathway. However, the underlying mechanism is not fully understood. Here, we show that rotenone elevates intracellular free calcium ion ([Ca2+]i) level, and activates CaMKII, resulting in inhibition of mTOR signaling and induction of neuronal apoptosis. Chelating [Ca2+]i with BAPTA/AM, preventing extracellular Ca2+ influx using EGTA, inhibiting CaMKII with KN93, or silencing CaMKII significantly attenuated rotenone-induced H2O2 production, mTOR inhibition, and cell death. Interestingly, using TTFA, antimycin A, catalase or Mito-TEMPO, we found that rotenone-induced mitochondrial H2O2 also in turn elevated [Ca2+]i level, thereby stimulating CaMKII, leading to inhibition of mTOR pathway and induction of neuronal apoptosis. Expression of wild type mTOR or constitutively active S6K1, or silencing 4E-BP1 strengthened the inhibitory effects of catalase, Mito-TEMPO, BAPTA/AM or EGTA on rotenone-induced [Ca2+]i elevation, CaMKII phosphorylation and neuronal apoptosis. Together, the results indicate that the crosstalk between Ca2+ signaling and mitochondrial H2O2 is required for rotenone inhibition of mTOR-mediated S6K1 and 4E-BP1 pathways. Our findings suggest that how to control over-elevation of intracellular Ca2+ and overproduction of mitochondrial H2O2 may be a new approach to deal with the neurotoxicity of rotenone. PMID:26859572

  3. mTOR pathway inhibition as a new therapeutic strategy in epilepsy and epileptogenesis.

    PubMed

    Citraro, Rita; Leo, Antonio; Constanti, Andrew; Russo, Emilio; De Sarro, Giovambattista

    2016-05-01

    Several preclinical and some clinical studies have revealed that the mammalian target of rapamycin (mTOR) signaling pathway is involved in both genetic and acquired epilepsy syndromes. Excessive activation of mTOR signaling, as a consequence of loss-of-function of genes encoding for tuberous sclerosis complex (TSC) 1 and 2, is linked to the development of cortical malformations and epilepsy. This mTOR hyperactivation is associated with different epileptogenic conditions under the term of 'mTORopathies' such as tuberous sclerosis, focal cortical dysplasia, hemimegalencephaly and ganglioglioma. mTOR overactivation produces brain abnormalities that include dysplastic neurons, abnormal cortical organization and astrogliosis. mTOR inhibitors (e.g. rapamycin) have consistent protective effects in various genetic (e.g. TSC models and WAG/Rij rats) and acquired (e.g. kainate or pilocarpine post-status epilepticus) epilepsy animal models. Furthermore, clinical studies in patients with TSC and cortical dysplasia (CD) have confirmed the effectiveness of mTOR inhibitors also in epileptic patients. Therefore, mTOR is currently a very good candidate as a target for epilepsy and epileptogenesis. This review describes the relevance of the mTOR pathway to epileptogenesis and its potential as a therapeutic target in epilepsy treatment by presenting the most recent findings on mTOR inhibitors. PMID:27049136

  4. The mTOR signalling cascade: paving new roads to cure neurological disease.

    PubMed

    Crino, Peter B

    2016-07-01

    Defining the multiple roles of the mechanistic (formerly 'mammalian') target of rapamycin (mTOR) signalling pathway in neurological diseases has been an exciting and rapidly evolving story of bench-to-bedside translational research that has spanned gene mutation discovery, functional experimental validation of mutations, pharmacological pathway manipulation, and clinical trials. Alterations in the dual contributions of mTOR - regulation of cell growth and proliferation, as well as autophagy and cell death - have been found in developmental brain malformations, epilepsy, autism and intellectual disability, hypoxic-ischaemic and traumatic brain injuries, brain tumours, and neurodegenerative disorders. mTOR integrates a variety of cues, such as growth factor levels, oxygen levels, and nutrient and energy availability, to regulate protein synthesis and cell growth. In line with the positioning of mTOR as a pivotal cell signalling node, altered mTOR activation has been associated with a group of phenotypically diverse neurological disorders. To understand how altered mTOR signalling leads to such divergent phenotypes, we need insight into the differential effects of enhanced or diminished mTOR activation, the developmental context of these changes, and the cell type affected by altered signalling. A particularly exciting feature of the tale of mTOR discovery is that pharmacological mTOR inhibitors have shown clinical benefits in some neurological disorders, such as tuberous sclerosis complex, and are being considered for clinical trials in epilepsy, autism, dementia, traumatic brain injury, and stroke. PMID:27340022

  5. Resveratrol induces autophagy by directly inhibiting mTOR through ATP competition.

    PubMed

    Park, Dohyun; Jeong, Heeyoon; Lee, Mi Nam; Koh, Ara; Kwon, Ohman; Yang, Yong Ryoul; Noh, Jungeun; Suh, Pann-Ghill; Park, Hwangseo; Ryu, Sung Ho

    2016-01-01

    Resveratrol (RSV) is a natural polyphenol that has a beneficial effect on health, and resveratrol-induced autophagy has been suggested to be a key process in mediating many beneficial effects of resveratrol, such as reduction of inflammation and induction of cancer cell death. Although various resveratrol targets have been suggested, the molecule that mediates resveratrol-induced autophagy remains unknown. Here, we demonstrate that resveratrol induces autophagy by directly inhibiting the mTOR-ULK1 pathway. We found that inhibition of mTOR activity and presence of ULK1 are required for autophagy induction by resveratrol. In line with this mTOR dependency, we found that resveratrol suppresses the viability of MCF7 cells but not of SW620 cells, which are mTOR inhibitor sensitive and insensitive cancer cells, respectively. We also found that resveratrol-induced cancer cell suppression occurred ULK1 dependently. For the mechanism of action of resveratrol on mTOR inhibition, we demonstrate that resveratrol directly inhibits mTOR. We found that resveratrol inhibits mTOR by docking onto the ATP-binding pocket of mTOR (i.e., it competes with ATP). We propose mTOR as a novel direct target of resveratrol, and inhibition of mTOR is necessary for autophagy induction. PMID:26902888

  6. The ketogenic diet inhibits the mammalian target of rapamycin (mTOR) pathway

    PubMed Central

    McDaniel, Sharon S.; Rensing, Nicholas R.; Thio, Liu Lin; Yamada, Kelvin A.; Wong, Michael

    2011-01-01

    Summary The ketogenic diet (KD) is an effective treatment for epilepsy, but its mechanisms of action are poorly understood. We investigated the hypothesis that KD inhibits mammalian target of rapamycin (mTOR) pathway signaling. The expression of pS6 and pAkt, markers of mTOR pathway activation, was reduced in hippocampus and liver of rats fed KD. In the kainate model of epilepsy, KD blocked the hippocampal pS6 elevation that occurs after status epilepticus. As mTOR signaling has been implicated in epileptogenesis, these results suggest that the KD may have anticonvulsant or antiepileptogenic actions via mTOR pathway inhibition. PMID:21371020

  7. Resveratrol induces autophagy by directly inhibiting mTOR through ATP competition

    PubMed Central

    Park, Dohyun; Jeong, Heeyoon; Lee, Mi Nam; Koh, Ara; Kwon, Ohman; Yang, Yong Ryoul; Noh, Jungeun; Suh, Pann-Ghill; Park, Hwangseo; Ryu, Sung Ho

    2016-01-01

    Resveratrol (RSV) is a natural polyphenol that has a beneficial effect on health, and resveratrol-induced autophagy has been suggested to be a key process in mediating many beneficial effects of resveratrol, such as reduction of inflammation and induction of cancer cell death. Although various resveratrol targets have been suggested, the molecule that mediates resveratrol-induced autophagy remains unknown. Here, we demonstrate that resveratrol induces autophagy by directly inhibiting the mTOR-ULK1 pathway. We found that inhibition of mTOR activity and presence of ULK1 are required for autophagy induction by resveratrol. In line with this mTOR dependency, we found that resveratrol suppresses the viability of MCF7 cells but not of SW620 cells, which are mTOR inhibitor sensitive and insensitive cancer cells, respectively. We also found that resveratrol-induced cancer cell suppression occurred ULK1 dependently. For the mechanism of action of resveratrol on mTOR inhibition, we demonstrate that resveratrol directly inhibits mTOR. We found that resveratrol inhibits mTOR by docking onto the ATP-binding pocket of mTOR (i.e., it competes with ATP). We propose mTOR as a novel direct target of resveratrol, and inhibition of mTOR is necessary for autophagy induction. PMID:26902888

  8. Ser2481-autophosphorylated mTOR colocalizes with chromosomal passenger proteins during mammalian cell cytokinesis.

    PubMed

    Vazquez-Martin, Alejandro; Sauri-Nadal, Tamara; Menendez, Octavio J; Oliveras-Ferraros, Cristina; Cufí, Sílvia; Corominas-Faja, Bruna; López-Bonet, Eugeni; Menendez, Javier A

    2012-11-15

    Energy- and nutrient-sensing proteins such as AMPK, mTOR and S6K1 are now recognized as novel regulators of mitotic completion in proliferating cells. We investigated the cellular distribution of the Ser2481 autophosphorylation of mTOR, which directly monitors mTORC-specific catalytic activity, during mammalian cell mitosis and cytokinesis. Automated immunofluorescence experiments in human carcinoma cell lines revealed that phospho-mTOR (Ser2481) exhibited profound spatial and temporal dynamics during cell division. Phospho-mTOR (Ser2481) was strikingly enriched in mitotic cells, and in prophase, bright phospho-mTOR (Ser2481) staining could be clearly observed among condensed chromosomes. Phospho-mTOR (Ser2481) then redistributes from diffuse cytosolic staining that partially colocalizes with the mitotic spindle during the early phases of mitosis to the furrow at the onset of cytokinesis. Like the bona fide chromosomal passenger proteins (CPPs) INCENP and Aurora B, phospho-mTOR (Ser2481) displayed noteworthy accumulation in the central spindle midzone and the midbody regions, which persisted during the furrowing process. Accordingly, double-staining experiments confirmed that phospho-mTOR (Ser2481) largely colocalized with CCPs in the midbodies. The CPP-like mitotic localization of phospho-mTOR (Ser2481) was fully prevented by the microtubule-depolymerizing drug nocodazole; mitotic traveling of phospho-mTOR (Ser2481) to the midbody during telophase and cytokinesis, where it appears to be integrated into the CPP-driven cytokinetic machinery, may therefore require dynamic microtubules. Although the Ser2448-phosphorylated form of mTOR was also found at high levels during M-phase in human cancer cells, we failed to observe a significant association of phospho-mTOR (Ser2448) with CCP-positive mitotic and cytokinetic structures. Our findings add phospho-mTOR (Ser2481) to the growing list of phospho-active forms of proteins belonging to the AMPK/mTOR/S6K1 signaling axis

  9. Everolimus-induced epithelial to mesenchymal transition in immortalized human renal proximal tubular epithelial cells: key role of heparanase

    PubMed Central

    2013-01-01

    Background Everolimus (EVE) is a drug widely used in several renal transplant protocols. Although characterized by a relatively low nephrotoxicity, it may induce several adverse effects including severe fibro-interstitial pneumonitis. The exact molecular/biological mechanism associated to these pro-fibrotic effects is unknown, but epithelial to mesenchymal transition (EMT) may have a central role. Additionally, heparanase, an enzyme recently associated with the progression of chronic allograft nephropathy, could contribute to activate this machinery in renal cells. Methods Several biomolecular strategies (RT-PCR, immunofluorescence, zymography and migration assay) have been used to assess the capability of EVE (10, 100, 200 and 500 nM) to induce an in vitro heparanase-mediated EMT in wild-type (WT) and Heparanase (HPSE)-silenced immortalized human renal epithelial proximal tubular cells (HK-2). Additionally, microarray technology was used to find additional biological elements involved in EVE-induced EMT. Results Biomolecular experiments demonstrated a significant up-regulation (more than 1.5 fold increase) of several genes encoding for well known EMT markers [(alpha-smooth muscle actin (α-SMA), Vimentin (VIM), Fibronectin (FN) and matrix metalloproteinase-9 (MMP9)], enhancement of MMP9 protein level and increment of cells motility in WT HK2 cells treated with high concentrations of EVE (higher than 100 nM). Similarly, immunofluorescence analysis showed that 100 nM of EVE increased α-SMA, VIM and FN protein expression in WT HK2 cells. All these effects were absent in both HPSE- and AKT-silenced cell lines. AKT is a protein having a central role in EMT. Additionally, microarray analysis identified other 2 genes significantly up-regulated in 100 nM EVE-treated cells (p < 0.005 and FDR < 5%): transforming growth factor beta-2 (TGFβ2) and epidermal growth factor receptor (EGFR). Real-time PCR analysis validated microarray. Conclusions Our in vitro study

  10. A Phase 1 Study of Everolimus + Weekly Cisplatin + Intensity Modulated Radiation Therapy in Head-and-Neck Cancer

    SciTech Connect

    Fury, Matthew G.; Lee, Nancy Y.; Sherman, Eric; Ho, Alan L.; Rao, Shyam; Heguy, Adriana; Shen, Ronglai; Korte, Susan; Lisa, Donna; Ganly, Ian; Patel, Snehal; Wong, Richard J.; Shaha, Ashok; Shah, Jatin; Haque, Sofia; Katabi, Nora; Pfister, David G.

    2013-11-01

    Purpose: Elevated expression of eukaryotic protein synthesis initiation factor 4E (eIF4E) in histologically cancer-free margins of resected head and neck squamous cell carcinomas (HNSCCs) is mediated by mammalian target of rapamycin complex 1 (mTORC1) and has been associated with increased risk of disease recurrence. Preclinically, inhibition of mTORC1 with everolimus sensitizes cancer cells to cisplatin and radiation. Methods and Materials: This was single-institution phase 1 study to establish the maximum tolerated dose of daily everolimus given with fixed dose cisplatin (30 mg/m{sup 2} weekly × 6) and concurrent intensity modulated radiation therapy for patients with locally and/or regionally advanced head-and-neck cancer. The study had a standard 3 + 3 dose-escalation design. Results: Tumor primary sites were oral cavity (4), salivary gland (4), oropharynx (2), nasopharynx (1), scalp (1), and neck node with occult primary (1). In 4 of 4 cases in which resected HNSCC surgical pathology specimens were available for immunohistochemistry, elevated expression of eIF4E was observed in the cancer-free margins. The most common grade ≥3 treatment-related adverse event was lymphopenia (92%), and dose-limiting toxicities (DLTs) were mucositis (n=2) and failure to thrive (n=1). With a median follow up of 19.4 months, 2 patients have experienced recurrent disease. The maximum tolerated dose was everolimus 5 mg/day. Conclusions: Head-and-neck cancer patients tolerated everolimus at therapeutic doses (5 mg/day) given with weekly cisplatin and intensity modulated radiation therapy. The regimen merits further evaluation, especially among patients who are status post resection of HNSCCs that harbor mTORC1-mediated activation of eIF4E in histologically negative surgical margins.

  11. Mechanical stimulation induces mTOR signaling via an ERK-independent mechanism: implications for a direct activation of mTOR by phosphatidic acid.

    PubMed

    You, Jae Sung; Frey, John W; Hornberger, Troy A

    2012-01-01

    Signaling by mTOR is a well-recognized component of the pathway through which mechanical signals regulate protein synthesis and muscle mass. However, the mechanisms involved in the mechanical regulation of mTOR signaling have not been defined. Nevertheless, recent studies suggest that a mechanically-induced increase in phosphatidic acid (PA) may be involved. There is also evidence which suggests that mechanical stimuli, and PA, utilize ERK to induce mTOR signaling. Hence, we reasoned that a mechanically-induced increase in PA might promote mTOR signaling via an ERK-dependent mechanism. To test this, we subjected mouse skeletal muscles to mechanical stimulation in the presence or absence of a MEK/ERK inhibitor, and then measured several commonly used markers of mTOR signaling. Transgenic mice expressing a rapamycin-resistant mutant of mTOR were also used to confirm the validity of these markers. The results demonstrated that mechanically-induced increases in p70(s6k) T389 and 4E-BP1 S64 phosphorylation, and unexpectedly, a loss in total 4E-BP1, were fully mTOR-dependent signaling events. Furthermore, we determined that mechanical stimulation induced these mTOR-dependent events, and protein synthesis, through an ERK-independent mechanism. Similar to mechanical stimulation, exogenous PA also induced mTOR-dependent signaling via an ERK-independent mechanism. Moreover, PA was able to directly activate mTOR signaling in vitro. Combined, these results demonstrate that mechanical stimulation induces mTOR signaling, and protein synthesis, via an ERK-independent mechanism that potentially involves a direct interaction of PA with mTOR. Furthermore, it appears that a decrease in total 4E-BP1 may be part of the mTOR-dependent mechanism through which mechanical stimuli activate protein synthesis. PMID:23077579

  12. Everolimus as second- or third-line treatment of advanced endometrial cancer: ENDORAD, a phase II trial of GINECO

    PubMed Central

    Ray-Coquard, I; Favier, L; Weber, B; Roemer-Becuwe, C; Bougnoux, P; Fabbro, M; Floquet, A; Joly, F; Plantade, A; Paraiso, D; Pujade-Lauraine, E

    2013-01-01

    Background: Patients with recurrent/metastatic endometrial cancer that progresses after chemotherapy have limited treatment options and poor outcomes. Preclinical data suggest the oral mammalian target of rapamycin inhibitor everolimus may provide clinical benefit in these patients. Methods: In this multicenter, open-label, phase 2 study, patients with advanced or metastatic endometrial cancer refractory to one or two previous chemotherapy regimens received everolimus 10 mg per day until progression or unacceptable toxicity. Primary end point was the non-progressive disease rate at 3 months. Secondary end points included duration of response, progression-free, and overall survival (OS), and safety. Results: Forty-four patients were enrolled (median age, 65 years); 66% received one previous chemotherapy regimen. The 3-month non-progressive disease rate was 36% (95% confidence interval 22–52%), including two patients (5%) with partial response (PR). At 6 months, two additional patients experienced PR. Median duration of response was 3.1 months. Median progression-free and OS were 2.8 months and 8.1 months, respectively. The most common adverse events were anaemia (100%), fatigue (93%), hypercholesterolaemia (81%), and lymphopenia (81%). Conclusion: Everolimus demonstrated efficacy and acceptable tolerability in patients with chemotherapy-refractory advanced or metastatic endometrial cancer. These results support the further development of phosphatidylinositol 3-kinase-targeted therapies in endometrial cancer. PMID:23612453

  13. Comparison of everolimus-eluting and biolimus-eluting coronary stents with everolimus-eluting bioresorbable scaffold: study protocol of the randomized controlled EVERBIO II trial

    PubMed Central

    2014-01-01

    Background Second-generation everolimus-eluting stents (EES) and third generation biolimus-eluting stents (BES) have been shown to be superior to first-generation paclitaxel-eluting stents (PES) and second-generation sirolimus-eluting stents (SES). However, neointimal proliferation and very late stent thrombosis is still an unresolved issue of drug-eluting stent (DES) implantation overall. The Absorb™ (Abbott Vascular, Abbott Park, IL, USA) is the first CE approved DES with a bioresorbable vascular scaffold (BVS) thought to reduce long-term complication rates. The EVERBIO II trial was set up to compare the BVS safety and efficacy with both EES and BES in all patients viable for inclusion. Methods/Design The EVERBIO II trial is a single-center, assessor-blinded, randomized trial. The study population consists of all patients aged ≥18 years old undergoing percutaneous coronary intervention. Exclusion criterion is where the lesion cannot be treated with BVS (reference vessel diameter >4.0 mm). A total of 240 patients will be enrolled and randomly assigned into 3 groups of 80 with either BVS, EES or BES implantation. All patients will undergo a follow-up angiography study at 9 months. Clinical follow-up for up to 5 years will be conducted by telephone. The primary endpoint is in-segment late lumen loss at 9 months measured by quantitative coronary angiography. Secondary endpoints are patient-oriented major adverse cardiac event (MACE) (death, myocardial infarction and target-vessel revascularization), device-oriented MACE (cardiac death, myocardial infarction and target-lesion revascularization), stent thrombosis according to ARC and binary restenosis at follow-up 12 months angiography. Discussion EVERBIO II is an independent, randomized study, aiming to compare the clinical efficacy, angiographic outcomes and safety of BVS, EES and BES in all comer patients. Trial registration The trial listed in clinicaltrials.gov as NCT01711931. PMID:24398143

  14. Skeletal myocyte hypertrophy requires mTOR kinase activity and S6K1

    SciTech Connect

    Park, In-Hyun . E-mail: ihpark@uiuc.edu; Erbay, Ebru; Nuzzi, Paul; Chen Jie

    2005-09-10

    The protein kinase mammalian target of rapamycin (mTOR) is a central regulator of cell proliferation and growth, with the ribosomal subunit S6 kinase 1 (S6K1) as one of the key downstream signaling effectors. A critical role of mTOR signaling in skeletal muscle differentiation has been identified recently, and an unusual regulatory mechanism independent of mTOR kinase activity and S6K1 is revealed. An mTOR pathway has also been reported to regulate skeletal muscle hypertrophy, but the regulatory mechanism is not completely understood. Here, we report the investigation of mTOR's function in insulin growth factor I (IGF-I)-induced C2C12 myotube hypertrophy. Added at a later stage when rapamycin no longer had any effect on normal myocyte differentiation, rapamycin completely blocked myocyte hypertrophy as measured by myotube diameter. Importantly, a concerted increase of average myonuclei per myotube was observed in IGF-I-stimulated myotubes, which was also inhibited by rapamycin added at a time when it no longer affected normal differentiation. The mTOR protein level, its catalytic activity, its phosphorylation on Ser2448, and the activity of S6K1 were all found increased in IGF-I-stimulated myotubes compared to unstimulated myotubes. Using C2C12 cells stably expressing rapamycin-resistant forms of mTOR and S6K1, we provide genetic evidence for the requirement of mTOR and its downstream effector S6K1 in the regulation of myotube hypertrophy. Our results suggest distinct mTOR signaling mechanisms in different stages of skeletal muscle development: While mTOR regulates the initial myoblast differentiation in a kinase-independent and S6K1-independent manner, the hypertrophic function of mTOR requires its kinase activity and employs S6K1 as a downstream effector.

  15. The mTOR pathway in obesity driven gastrointestinal cancers: Potential targets and clinical trials

    PubMed Central

    Malley, Cian O.; Pidgeon, Graham P.

    2015-01-01

    The mechanistic target of rapamycin (mTOR) is a crucial point of convergence between growth factor signalling, metabolism, nutrient status and cellular proliferation. The mTOR pathway is heavily implicated in the progression of many cancers and is emerging as an important driver of gastrointestinal (GI) malignancies. Due to its central role in adapting metabolism to environmental conditions, mTOR signalling is also believed to be critical in the development of obesity. Recent research has delineated that excessive nutrient intake can promote signalling through the mTOR pathway and possibly evoke changes to cellular metabolism that could accelerate obesity related cancers. Acting through its two effector complexes mTORC1 and mTORC2, mTOR dictates the transcription of genes important in glycolysis, lipogenesis, protein translation and synthesis and has recently been defined as a central mediator of the Warburg effect in cancer cells. Activation of the mTOR pathway is involved in both the pathogenesis of GI malignancies and development of resistance to conventional chemotherapy and radiotherapy. The use of mTOR inhibitors is a promising therapeutic option in many GI malignancies, with greatest clinical efficacy seen in combination regimens. Recent research has also provided insight into crosstalk between mTOR and other pathways which could potentially expand the list of therapeutic targets in the mTOR pathway. Here we review the available strategies for targeting the mTOR pathway in GI cancers. We discuss current clinical trials of both established and novel mTOR inhibitors, with particular focus on combinations of these drugs with conventional chemotherapy, radiotherapy and targeted therapies. PMID:27051587

  16. The mTOR pathway in obesity driven gastrointestinal cancers: Potential targets and clinical trials.

    PubMed

    Malley, Cian O; Pidgeon, Graham P

    2016-06-01

    The mechanistic target of rapamycin (mTOR) is a crucial point of convergence between growth factor signalling, metabolism, nutrient status and cellular proliferation. The mTOR pathway is heavily implicated in the progression of many cancers and is emerging as an important driver of gastrointestinal (GI) malignancies. Due to its central role in adapting metabolism to environmental conditions, mTOR signalling is also believed to be critical in the development of obesity. Recent research has delineated that excessive nutrient intake can promote signalling through the mTOR pathway and possibly evoke changes to cellular metabolism that could accelerate obesity related cancers. Acting through its two effector complexes mTORC1 and mTORC2, mTOR dictates the transcription of genes important in glycolysis, lipogenesis, protein translation and synthesis and has recently been defined as a central mediator of the Warburg effect in cancer cells. Activation of the mTOR pathway is involved in both the pathogenesis of GI malignancies and development of resistance to conventional chemotherapy and radiotherapy. The use of mTOR inhibitors is a promising therapeutic option in many GI malignancies, with greatest clinical efficacy seen in combination regimens. Recent research has also provided insight into crosstalk between mTOR and other pathways which could potentially expand the list of therapeutic targets in the mTOR pathway. Here we review the available strategies for targeting the mTOR pathway in GI cancers. We discuss current clinical trials of both established and novel mTOR inhibitors, with particular focus on combinations of these drugs with conventional chemotherapy, radiotherapy and targeted therapies. PMID:27051587

  17. Cost-effectiveness analysis of everolimus plus exemestane versus exemestane alone for treatment of hormone receptor positive metastatic breast cancer.

    PubMed

    Diaby, Vakaramoko; Adunlin, Georges; Zeichner, Simon B; Avancha, Kiran; Lopes, Gilberto; Gluck, Stefan; Montero, Alberto J

    2014-09-01

    Everolimus in combination with exemestane significantly improved progression-free survival compared to exemestane alone in patients previously treated with non-steroidal aromatase inhibitors in the BOLERO-2 trial. As a result, this combination has been approved by the food and drug administration to treat postmenopausal women with hormone receptor positive and HER2 negative metastatic breast cancer. A cost-effectiveness analysis was conducted to determine whether everolimus represents good value for money, utilizing data from BOLERO-2. A decision-analytic model was used to estimate the incremental cost-effectiveness ratio between treatment arms of the BOLERO-2 trial. Costs were obtained from the Center for Medicare Services drug payment table and physician fee schedule. Benefits were expressed as quality-adjusted progression-free survival weeks (QAPFW) and quality-adjusted progression-free years (QAPFY), with utilities/disutilities derived from the literature. Deterministic and probabilistic sensitivity analyses were performed. A willingness to pay threshold of 1-3 times the per capita gross domestic product was adopted, as per the definition of the World Health Organization. The U.S. per capita gross domestic product in 2013 was $49,965; thus, a threshold varying between $49,965 and $149,895 was considered. Everolimus/exemestane had an incremental benefit of 11.88 QAPFW (0.22 QAPFY) compared to exemestane and an incremental cost of $60,574. This translated into an ICER of $265,498.5/QAPFY. Univariate sensitivity analyses showed important variations of the ICER, ranging between $189,836.4 and $530,947/QAPFY. A tornado analysis suggested that the key drivers of our model, by order of importance, included health utility value for stable disease, everolimus acquisition costs, and transition probabilities from the stable to the progression states. The Monte-Carlo simulation showed results that were similar to the base-case analysis. This cost-effectiveness analysis

  18. ARD1 Stabilization of TSC2 Suppresses Tumorigenesis Through the mTOR Signaling Pathway

    PubMed Central

    Kuo, Hsu-Ping; Lee, Dung-Fang; Chen, Chun-Te; Liu, Mo; Chou, Chao-Kai; Lee, Hong-Jen; Du, Yi; Xie, Xiaoming; Wei, Yongkun; Xia, Weiya; Weihua, Zhang; Yang, Jer-Yen; Yen, Chia-Jui; Huang, Tzu-Hsuan; Tan, Minjia; Xing, Gang; Zhao, Yingming; Lin, Chien-Hsing; Tsai, Shih-Feng; Fidler, Isaiah J.; Hung, Mien-Chie

    2010-01-01

    Mammalian target of rapamycin (mTOR) regulates various cellular functions, including tumorigenesis, and is inhibited by the tuberous sclerosis 1 (TSC1)–TSC2 complex. Here, we demonstrate that arrest-defective protein 1 (ARD1) physically interacts with, acetylates, and stabilizes TSC2, thereby repressing mTOR activity. The inhibition of mTOR by ARD1 inhibits cell proliferation and increases autophagy, thereby inhibiting tumorigenicity. Correlation between ARD1 and TSC2 abundance was apparent in multiple tumor types. Moreover, evaluation of loss of heterozygosity at Xq28 revealed allelic loss in 31% of tested breast cancer cell lines and tumor samples. Together, our findings suggest that ARD1 functions as an inhibitor of the mTOR pathway and that dysregulation of the ARD1-TSC2-mTOR axis may contribute to cancer development. PMID:20145209

  19. Targeting bone metastatic cancer: Role of the mTOR pathway.

    PubMed

    Bertoldo, Francesco; Silvestris, Franco; Ibrahim, Toni; Cognetti, Francesco; Generali, Daniele; Ripamonti, Carla Ida; Amadori, Dino; Colleoni, Marco Angelo; Conte, Pierfranco; Del Mastro, Lucia; De Placido, Sabino; Ortega, Cinzia; Santini, Daniele

    2014-04-01

    One of the great challenges of cancer medicine is to develop effective treatments for bone metastatic cancer. Most patients with advanced solid tumors will develop bone metastasis and will suffer from skeletal related events associated with this disease. Although some therapies are available to manage symptoms derived from bone metastases, an effective treatment has not been developed yet. The mammalian target of rapamycin (mTOR) pathway regulates cell growth and survival. Alterations in mTOR signaling have been associated with pathological malignancies, including bone metastatic cancer. Inhibition of mTOR signaling might therefore be a promising alternative for bone metastatic cancer management. This review summarizes the current knowledge on mTOR pathway signaling in bone tissue and provides an overview on the known effects of mTOR inhibition in bone cancer, both in in vitro and in vivo models. PMID:24508774

  20. Role of mTOR signaling in intestinal cell migration

    PubMed Central

    Rhoads, J. Marc; Niu, Xiaomei; Odle, Jack; Graves, Lee M.

    2006-01-01

    An early signaling event activated by amino acids and growth factors in many cell types is the phosphorylation of the mammalian target of rapamycin (mTOR; FRAP), which is functionally linked to ribosomal protein s6 kinase (p70s6k), a kinase that plays a critical regulatory role in the translation of mRNAs and protein synthesis. We previously showed that intestinal cell migration, the initial event in epithelial restitution, is enhanced by l-arginine (ARG). In this study, we used amino acids as prototypic activators of mTOR and ARG, IGF-1, or serum as recognized stimulators of intestinal cell migration. We found that 1) protein synthesis is required for intestinal cell migration, 2) mTOR/p70s6k pathway inhibitors (rapamycin, wortmannin, and intracellular Ca2+ chelation) inhibit cell migration, 3) ARG activates migration and mTOR/p70s6k (but not ERK-2) in migrating enterocytes, and 4) immunocytochemistry reveals abundant p70s6k staining in cytoplasm, whereas phosphop70s6k is virtually all intranuclear in resting cells but redistributes to the periphery on activation by ARG. We conclude that mTOR/p70s6k signaling is essential to intestinal cell migration, is activated by ARG, involves both nuclear and cytoplasmic events, and may play a role in intestinal repair. PMID:16710051

  1. Ammonia Induces Autophagy through Dopamine Receptor D3 and MTOR

    PubMed Central

    Li, Zhiyuan; Ji, Xinmiao; Wang, Wenchao; Liu, Juanjuan; Liang, Xiaofei; Wu, Hong; Liu, Jing; Eggert, Ulrike S.; Liu, Qingsong

    2016-01-01

    Hyperammonemia is frequently seen in tumor microenvironments as well as in liver diseases where it can lead to severe brain damage or death. Ammonia induces autophagy, a mechanism that tumor cells may use to protect themselves from external stresses. However, how cells sense ammonia has been unclear. Here we show that culture medium alone containing Glutamine can generate milimolar of ammonia at 37 degrees in the absence of cells. In addition, we reveal that ammonia acts through the G protein-coupled receptor DRD3 (Dopamine receptor D3) to induce autophagy. At the same time, ammonia induces DRD3 degradation, which involves PIK3C3/VPS34-dependent pathways. Ammonia inhibits MTOR (mechanistic target of Rapamycin) activity and localization in cells, which is mediated by DRD3. Therefore, ammonia has dual roles in autophagy: one to induce autophagy through DRD3 and MTOR, the other to increase autophagosomal pH to inhibit autophagic flux. Our study not only adds a new sensing and output pathway for DRD3 that bridges ammonia sensing and autophagy induction, but also provides potential mechanisms for the clinical consequences of hyperammonemia in brain damage, neurodegenerative diseases and tumors. PMID:27077655

  2. mTOR signaling in autophagy regulation in the kidney

    PubMed Central

    Inoki, Ken

    2016-01-01

    Cells possess adaptive biosynthetic systems to maintain cellular energy levels for survival under adverse environmental conditions. Autophagy is an evolutionarily conserved cellular catabolic process that breaks down and recycles cytosolic material including macromolecules and organelles through lysosomal degradation. This catabolic process, represented by macroautophagy, is induced by a variety of cellular stresses such as nutrient starvation, which causes a shortage of cellular energy for cells to maintain cellular homeostasis and essential biological activities. In contrast, upon nutrient availability, cells stimulate anabolic processes. The mechanistic/mammalian target rapamycin (mTOR), a serine/threonine protein kinase, is a key player in stimulating cellular anabolism in response to nutrients and growth factors, and plays a crucial role in suppressing autophagy activity. Growing evidence has suggested that autophagy activity is required for the maintenance and physiological functions of renal cells including proximal tubular cells and podocytes. In this section, we will discuss recent progresses in the regulation of autophagy by the mTOR signaling. PMID:24485024

  3. Targeting the mTOR Pathway in Leukemia.

    PubMed

    Dinner, Shira; Platanias, Leonidas C

    2016-08-01

    Optimal function of multiple intracellular signaling pathways is essential for normal regulation of cellular transcription, translation, growth, proliferation, and survival. Dysregulation or aberrant activation of such cascades can lead to inappropriate cell survival and abnormal cell proliferation in leukemia. Successful treatment of chronic myeloid leukemia (CML) with tyrosine kinase inhibitors targeting the BCR-ABL fusion gene is a prime example of effectively inhibiting intracellular signaling cascades. However, even in these patients resistance can develop via emergence of mutations or feedback activation of other pathways that cause refractory disease. Constitutive activation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway has been observed in different types of leukemia, including CML, acute myeloid leukemia, and acute lymphoblastic leukemia. Abnormal mTOR activity may contribute to chemotherapy resistance, while it may also be effectively targeted via molecular means and/or development of specific pharmacological inhibitors. This review discusses the role of PI3K/Akt/mTOR dysre-gulation in leukemia and summarizes the emergence of preliminary data for the development of novel therapeutic approaches. J. Cell. Biochem. 117: 1745-1752, 2016. © 2016 Wiley Periodicals, Inc. PMID:27018341

  4. Mammalian Target of Rapamycin (mTOR) Tagging Promotes Dendritic Branch Variability through the Capture of Ca2+/Calmodulin-dependent Protein Kinase II α (CaMKIIα) mRNAs by the RNA-binding Protein HuD.

    PubMed

    Sosanya, Natasha M; Cacheaux, Luisa P; Workman, Emily R; Niere, Farr; Perrone-Bizzozero, Nora I; Raab-Graham, Kimberly F

    2015-06-26

    The fate of a memory, whether stored or forgotten, is determined by the ability of an active or tagged synapse to undergo changes in synaptic efficacy requiring protein synthesis of plasticity-related proteins. A synapse can be tagged, but without the "capture" of plasticity-related proteins, it will not undergo long lasting forms of plasticity (synaptic tagging and capture hypothesis). What the "tag" is and how plasticity-related proteins are captured at tagged synapses are unknown. Ca(2+)/calmodulin-dependent protein kinase II α (CaMKIIα) is critical in learning and memory and is synthesized locally in neuronal dendrites. The mechanistic (mammalian) target of rapamycin (mTOR) is a protein kinase that increases CaMKIIα protein expression; however, the mechanism and site of dendritic expression are unknown. Herein, we show that mTOR activity mediates the branch-specific expression of CaMKIIα, favoring one secondary, daughter branch over the other in a single neuron. mTOR inhibition decreased the dendritic levels of CaMKIIα protein and mRNA by shortening its poly(A) tail. Overexpression of the RNA-stabilizing protein HuD increased CaMKIIα protein levels and preserved its selective expression in one daughter branch over the other when mTOR was inhibited. Unexpectedly, deleting the third RNA recognition motif of HuD, the domain that binds the poly(A) tail, eliminated the branch-specific expression of CaMKIIα when mTOR was active. These results provide a model for one molecular mechanism that may underlie the synaptic tagging and capture hypothesis where mTOR is the tag, preventing deadenylation of CaMKIIα mRNA, whereas HuD captures and promotes its expression in a branch-specific manner. PMID:25944900

  5. The everolimus-eluting Xience stent in small vessel disease: bench, clinical, and pathology view

    PubMed Central

    Sanchez, Oscar D; Yahagi, Kazuyuki; Koppara, Tobias; Virmani, Renu; Joner, Michael

    2015-01-01

    Coronary artery disease (CAD) is the leading cause of morbidity and mortality worldwide. The pathogenesis of CAD relates to the presence of atherosclerotic plaques in the coronary arteries, which are most frequently treated today by percutaneous coronary intervention. Small vessel disease treatment represents one-third of all percutaneous coronary interventions with higher rates of restenosis and major adverse cardiac events. Initially, drug-eluting stents (DES) were developed to reduce in-stent restenosis, improving clinical outcomes and reducing the need for target vessel revascularization. However, late and very late stent thrombosis emerged as a new problem compromising DES’s long-term results. The cobalt–chromium everolimus-eluting stent (CoCr-EES) represents the results of an evolutionary process in DES technology aimed at improving the shortcomings of first-generation DES. Small vessel CAD has historically been an obstacle to long-term patency following implantation of DES. Antirestenotic efficacy has been shown to be of high relevance in small vessels. Therefore, stent selection may play an important role in determining outcomes in this subgroup of patients. This article will review the performance of CoCr-EES in the treatment of small vessel CAD from preclinical, clinical, and pathology perspectives, and it will highlight the most important findings in this regard. PMID:25565907

  6. Sotrastaurin in calcineurin inhibitor-free regimen using everolimus in de novo kidney transplant recipients.

    PubMed

    Tedesco-Silva, H; Kho, M M L; Hartmann, A; Vitko, S; Russ, G; Rostaing, L; Budde, K; Campistol, J M; Eris, J; Krishnan, I; Gopalakrishnan, U; Klupp, J

    2013-07-01

    Sotrastaurin, a novel selective protein-kinase-C inhibitor, inhibits early T cell activation via a calcineurin-independent pathway. Efficacy and safety of sotrastaurin in a calcineurin inhibitor-free regimen were evaluated in this two-stage Phase II study of de novo kidney transplant recipients. Stage 1 randomized 131 patients (2:1) to sotrastaurin 300 mg or cyclosporine A (CsA). Stage 2 randomized 180 patients (1:1:1) to sotrastaurin 300 or 200 mg or CsA. All patients received basiliximab, everolimus (EVR) and prednisone. Primary endpoint was composite efficacy failure rate of treated biopsy-proven acute rejection, graft loss, death or lost to follow-up. Main safety assessment was estimated glomerular filtration rate (eGFR) by MDRD-4 at Month 12. Composite efficacy failure rates at 12 months were higher in sotrastaurin arms (Stage 1: 16.5% and 10.9% for sotrastaurin 300 mg and CsA; Stage 2: 27.2%, 34.5% and 19.4% for sotrastaurin 200 mg, 300 mg and CsA). eGFR was significantly better in sotrastaurin groups versus CsA at most time points, except at 12 months. Gastrointestinal and cardiac adverse events were more frequent with sotrastaurin. Higher treatment discontinuation, deaths and graft losses occurred with sotrastaurin 300 mg. Sotrastaurin combined with EVR showed higher efficacy failure rates and some improvement in renal allograft function compared to a CsA-based therapy. PMID:23659755

  7. A comprehensive review of everolimus clinical reports: a new mammalian target of rapamycin inhibitor.

    PubMed

    Gurk-Turner, Cheryle; Manitpisitkul, Wana; Cooper, Matthew

    2012-10-15

    As new immunosuppressive agents are introduced to the market, clinicians are faced with the daunting task of sifting through the published literature to decide the value that the agent will add to their own practice. We often must extrapolate information provided through study in other solid-organ transplantation populations than our specific area of interest as we interpret the results and outcomes. With these challenges in mind, this compilation of published work for the newest mammalian target of rapamycin inhibitor everolimus (Certican; Novartis Pharmaceuticals, Hanover, NJ) (Zortress; Novartis Pharmaceuticals, Basel, Switzerland) is intended to provide a concise but thorough presentation of available literature so that the reader who may be unfamiliar with the agent can make their own judgment. Both Ovid and PubMed search engines were queried with a particular focus on high-impact articles noted in the Web of Science or Citation Index. Work described solely in abstract or case report form was excluded, as well as meta-analyses or those that were editorial or commentary in nature. Included were publications presented using the English language that described adult human subjects who received a heart, lung, kidney, or liver allograft. The goal of this strategy was to allow for the inclusion of pertinent literature in an unbiased fashion. Tables are provided that outline trial specific information, leaving a discussion of major outcomes to the text of the review. PMID:22986894

  8. Usefulness of Everolimus-Eluting Coronary Stent Implantation in Patients on Maintenance Hemodialysis.

    PubMed

    Ikari, Yuji; Kyono, Hiroyuki; Isshiki, Takaaki; Ishizuka, Shuichi; Nasu, Kenya; Sano, Koichi; Okada, Hisayuki; Sugano, Teruyasu; Uehara, Yoshiki

    2015-09-15

    The outcomes of second-generation drug-eluting stent (DES) are unknown in patients on maintenance hemodialysis (HD) although HD has been reported as a strong predictor of adverse outcome after the first-generation DES implantation. The OUCH-PRO Study is a prospective multicenter single-arm registry design to study clinical and angiographic outcomes after everolimus-eluting stent (EES). Patients who underwent maintenance HD were prospectively enrolled at the time of elective coronary intervention using EES. Quantitative coronary angiography was performed in an independent core laboratory. The primary end point was the occurrence of target vessel failure (TVF) defined as cardiac death, myocardial infarction (MI), and target vessel revascularization at 1 year. A total of 123 patients were enrolled and 161 EES were implanted. The TVF rate at 1 year was 18% (4% cardiac death, 0% MI, 17% target vessel revascularization). No stent thrombosis was documented. Other clinical events at 1 year were 3% noncardiac death, 3% stroke, and 9% non-target-vessel revascularization. Late lumen loss in stent was 0.37 ± 0.63 mm at 8 months. In conclusion, EES had a high TVF rate and great late lumen loss in patients on HD compared with previous huge EES data in non-HD patients. PMID:26219496

  9. A novel platinum chromium everolimus-eluting stent for the treatment of coronary artery disease

    PubMed Central

    Bennett, Johan; Dubois, Christophe

    2013-01-01

    The development of coronary stents represents a major step forward in the treatment of obstructive coronary artery disease since the introduction of percutaneous coronary intervention. The initial enthusiasm for bare metal stents was, however, tempered by a significant incidence of in-stent restenosis, the manifestation of excessive neointima hyperplasia within the stented vessel segment, ultimately leading to target vessel revascularization. Later, drug-eluting stents, with controlled local release of antiproliferative agents, consistently reduced this need for repeat revascularization. In turn, the long-term safety of first-generation drug-eluting stents was brought into question with the observation of an increased incidence of late stent thrombosis, often presenting as myocardial infarction or sudden death. Since then, new drugs, polymers, and platforms for drug elution have been developed to improve stent safety and preserve efficacy. Development of a novel platinum chromium alloy with high radial strength and high radiopacity has enabled the design of a new, thin-strut, flexible, and highly trackable stent platform, while simultaneously improving stent visibility. Significant advances in polymer coating, serving as a drug carrier on the stent surface, and in antiproliferative agent technology have further improved the safety and clinical performance of newer-generation drug-eluting stents. This review will provide an overview of the novel platinum chromium everolimus-eluting stents that are currently available. The clinical data from major clinical trials with these devices will be summarized and put into perspective. PMID:23818756

  10. RTOG 0913: A Phase 1 Study of Daily Everolimus (RAD001) in Combination With Radiation Therapy and Temozolomide in Patients With Newly Diagnosed Glioblastoma

    SciTech Connect

    Chinnaiyan, Prakash; Won, Minhee; Wen, Patrick Y.; Wendland, Merideth; Dipetrillo, Thomas A.; Corn, Benjamin W.; Mehta, Minesh P.

    2013-08-01

    Purpose: To determine the safety of the mammalian target of rapamycin inhibitor everolimus (RAD001) administered daily with concurrent radiation and temozolomide in newly diagnosed glioblastoma patients. Methods and Materials: Everolimus was administered daily with concurrent radiation (60 Gy in 30 fractions) and temozolomide (75 mg/m{sup 2} per day). Everolimus was escalated from 2.5 mg/d (dose level 1) to 5 mg/d (dose level 2) to 10 mg/d (dose level 3). Adjuvant temozolomide was delivered at 150 to 200 mg/m{sup 2} on days 1 to 5, every 28 days, for up to 12 cycles, with concurrent everolimus at the previously established daily dose of 10 mg/d. Dose escalation continued if a dose level produced dose-limiting toxicities (DLTs) in fewer than 3 of the first 6 evaluable patients. Results: Between October 28, 2010, and July 2, 2012, the Radiation Therapy Oncology Group 0913 protocol initially registered a total of 35 patients, with 25 patients successfully meeting enrollment criteria receiving the drug and evaluable for toxicity. Everolimus was successfully escalated to the predetermined maximum tolerated dose of 10 mg/d. Two of the first 6 eligible patients had a DLT at each dose level. DLTs included gait disturbance, febrile neutropenia, rash, fatigue, thrombocytopenia, hypoxia, ear pain, headache, and mucositis. Other common toxicities were grade 1 or 2 hypercholesterolemia and hypertriglyceridemia. At the time of analysis, there was 1 death reported, which was attributed to tumor progression. Conclusions: Daily oral everolimus (10 mg) combined with both concurrent radiation and temozolomide followed by adjuvant temozolomide is well tolerated, with an acceptable toxicity profile. A randomized phase 2 clinical trial with mandatory correlative biomarker analysis is currently under way, designed to both determine the efficacy of this regimen and identify molecular determinants of response.

  11. Caffeine affects the biological responses of human hematopoietic cells of myeloid lineage via downregulation of the mTOR pathway and xanthine oxidase activity

    PubMed Central

    Abooali, Maryam; Yasinska, Inna M.; Casely-Hayford, Maxwell A.; Berger, Steffen M.; Fasler-Kan, Elizaveta; Sumbayev, Vadim V.

    2015-01-01

    Correction of human myeloid cell function is crucial for the prevention of inflammatory and allergic reactions as well as leukaemia progression. Caffeine, a naturally occurring food component, is known to display anti-inflammatory effects which have previously been ascribed largely to its inhibitory actions on phosphodiesterase. However, more recent studies suggest an additional role in affecting the activity of the mammalian target of rapamycin (mTOR), a master regulator of myeloid cell translational pathways, although detailed molecular events underlying its mode of action have not been elucidated. Here, we report the cellular uptake of caffeine, without metabolisation, by healthy and malignant hematopoietic myeloid cells including monocytes, basophils and primary acute myeloid leukaemia mononuclear blasts. Unmodified caffeine downregulated mTOR signalling, which affected glycolysis and the release of pro-inflammatory/pro-angiogenic cytokines as well as other inflammatory mediators. In monocytes, the effects of caffeine were potentiated by its ability to inhibit xanthine oxidase, an enzyme which plays a central role in human purine catabolism by generating uric acid. In basophils, caffeine also increased intracellular cyclic adenosine monophosphate (cAMP) levels which further enhanced its inhibitory action on mTOR. These results demonstrate an important mode of pharmacological action of caffeine with potentially wide-ranging therapeutic impact for treating non-infectious disorders of the human immune system, where it could be applied directly to inflammatory cells. PMID:26384306

  12. Caffeine affects the biological responses of human hematopoietic cells of myeloid lineage via downregulation of the mTOR pathway and xanthine oxidase activity.

    PubMed

    Gibbs, Bernhard F; Gonçalves Silva, Isabel; Prokhorov, Alexandr; Abooali, Maryam; Yasinska, Inna M; Casely-Hayford, Maxwell A; Berger, Steffen M; Fasler-Kan, Elizaveta; Sumbayev, Vadim V

    2015-10-01

    Correction of human myeloid cell function is crucial for the prevention of inflammatory and allergic reactions as well as leukaemia progression. Caffeine, a naturally occurring food component, is known to display anti-inflammatory effects which have previously been ascribed largely to its inhibitory actions on phosphodiesterase. However, more recent studies suggest an additional role in affecting the activity of the mammalian target of rapamycin (mTOR), a master regulator of myeloid cell translational pathways, although detailed molecular events underlying its mode of action have not been elucidated. Here, we report the cellular uptake of caffeine, without metabolisation, by healthy and malignant hematopoietic myeloid cells including monocytes, basophils and primary acute myeloid leukaemia mononuclear blasts. Unmodified caffeine downregulated mTOR signalling, which affected glycolysis and the release of pro-inflammatory/pro-angiogenic cytokines as well as other inflammatory mediators. In monocytes, the effects of caffeine were potentiated by its ability to inhibit xanthine oxidase, an enzyme which plays a central role in human purine catabolism by generating uric acid. In basophils, caffeine also increased intracellular cyclic adenosine monophosphate (cAMP) levels which further enhanced its inhibitory action on mTOR. These results demonstrate an important mode of pharmacological action of caffeine with potentially wide-ranging therapeutic impact for treating non-infectious disorders of the human immune system, where it could be applied directly to inflammatory cells. PMID:26384306

  13. Pushing the envelope in the mTOR pathway. The second generation of inhibitors

    PubMed Central

    Vilar, Eduardo; Perez-Garcia, Jose; Tabernero, Josep

    2011-01-01

    The phosphatydilinositol-3-kinase (PI3K)/mammalian target of rapamycin (mTOR) pathway has been a major focus of attention for cancer researchers in the past decade. A preliminary and not complete understanding of the molecular biology of this complex network has not only importantly conditioned the development of the first generation of mTOR inhibitors, but also the biomarker studies designed to identify the best responders to these agents. Most recently, research in this pathway has focused in the fact of the dual nature of mTOR that is integrated by the mTOR complex 1 (mTORC1) and complex 2 (mTORC2). These two complexes are formed and regulated by different proteins, and also driven by multiple different compensatory feedback loops. This deeper understanding has allowed the development of a promising second generation of inhibitors which are able to block simultaneously both complexes due to their catalytic activity over mTOR. Moreover, some of them also exert an inhibitory effect over PI3K that is a key player in the feedback loops. This article reviews the newest insights in the signaling of the mTOR pathway and then focuses in the development of the new wave of mTOR inhibitors. PMID:21216931

  14. microRNA-496 - A new, potentially aging-relevant regulator of mTOR.

    PubMed

    Rubie, Claudia; Kölsch, Kathrin; Halajda, Beata; Eichler, Hermann; Wagenpfeil, Stefan; Roemer, Klaus; Glanemann, Matthias

    2016-01-01

    Recent findings strongly support a role for small regulatory RNAs in the regulation of human lifespan yet little information exists about the precise underlying mechanisms. Although extensive studies on model organisms have indicated that reduced activity of the nutrient response pathway, for example as a result of dietary restriction, can extend lifespan through the suppression of the protein kinase mechanistic target of rapamycin (mTOR), it still is subject of debate whether this mechanism is operative in humans as well. Here, we present findings indicating that human microRNA (miR)-496 targets 2 sites within the human mTOR 3'UTR. Coexpression of miR-496 with different fusion transcripts, consisting of the luciferase transcript and either wild-type mTOR 3'UTR or mTOR 3'UTR transcript with the miR-496 binding sites singly or combined mutated, confirmed this prediction and revealed cooperativity between the 2 binding sites. miR-496 reduced the mTOR protein level in HeLa-K cells, and the levels of miR-496 and mTOR protein were inversely correlated in Peripheral Blood Mononuclear Cells (PBMC), with old individuals (n = 40) harbouring high levels of miR-496 relative to young individuals (n = 40). Together, these findings point to the possibility that miR-496 is involved in the regulation of human aging through the control of mTOR. PMID:27097372

  15. Muscle inactivation of mTOR causes metabolic and dystrophin defects leading to severe myopathy

    PubMed Central

    Risson, Valérie; Mazelin, Laetitia; Roceri, Mila; Sanchez, Hervé; Moncollin, Vincent; Corneloup, Claudine; Richard-Bulteau, Hélène; Vignaud, Alban; Baas, Dominique; Defour, Aurélia; Freyssenet, Damien; Tanti, Jean-François; Le-Marchand-Brustel, Yannick; Ferrier, Bernard; Conjard-Duplany, Agnès; Romanino, Klaas; Bauché, Stéphanie; Hantaï, Daniel; Mueller, Matthias; Kozma, Sara C.; Thomas, George; Rüegg, Markus A.; Ferry, Arnaud; Pende, Mario; Bigard, Xavier; Koulmann, Nathalie

    2009-01-01

    Mammalian target of rapamycin (mTOR) is a key regulator of cell growth that associates with raptor and rictor to form the mTOR complex 1 (mTORC1) and mTORC2, respectively. Raptor is required for oxidative muscle integrity, whereas rictor is dispensable. In this study, we show that muscle-specific inactivation of mTOR leads to severe myopathy, resulting in premature death. mTOR-deficient muscles display metabolic changes similar to those observed in muscles lacking raptor, including impaired oxidative metabolism, altered mitochondrial regulation, and glycogen accumulation associated with protein kinase B/Akt hyperactivation. In addition, mTOR-deficient muscles exhibit increased basal glucose uptake, whereas whole body glucose homeostasis is essentially maintained. Importantly, loss of mTOR exacerbates the myopathic features in both slow oxidative and fast glycolytic muscles. Moreover, mTOR but not raptor and rictor deficiency leads to reduced muscle dystrophin content. We provide evidence that mTOR controls dystrophin transcription in a cell-autonomous, rapamycin-resistant, and kinase-independent manner. Collectively, our results demonstrate that mTOR acts mainly via mTORC1, whereas regulation of dystrophin is raptor and rictor independent. PMID:20008564

  16. mTOR and metabolic pathways in T cell quiescence and functional activation

    PubMed Central

    Yang, Kai; Chi, Hongbo

    2013-01-01

    The mechanistic target of rapamycin (mTOR), an evolutionally conserved serine and threonine kinase, plays a critical role in the promotion of cell growth and proliferation via integration of cellular and environmental cues. In adaptive immunity, the mTOR pathway orchestrates multiple physiological processes including the development and homeostasis of T cells under steady state, and their subsequent activation and differentiation upon antigen recognition. Associated with such fate decisions is the dynamic reprogramming of T cell metabolic pathways, as naïve, activated and memory cells are defined by distinct bioenergetic and biosynthetic activities. Emerging evidence indicates that mTOR signaling intersects with T cell metabolism at two major levels to constitute a critical control mechanism of T cell fate decisions. First, as a central environmental sensor, mTOR links immune signaling and the availability of nutrients, especially amino acids. Second, mTOR activates specific metabolic pathways in T cells such as aerobic glycolysis (also known as the “Warburg effect”) in a process dependent upon the induction of transcription factors MYC and HIF1α. Understanding how mTOR interplays with T cell metabolism to dictate T cell fates and functions will provide fundamental insights into the mechanism of immune responses and the development of novel therapeutics against immune-mediated diseases. In this review, we summarize the current advances on mTOR signaling and T cell metabolism in the control of development, homeostasis, activation and differentiation of T cells. PMID:23375549

  17. Inhibition of mTOR promotes hyperthermia sensitivity in SMMC-7721 human hepatocellular carcinoma cell line

    PubMed Central

    WANG, QING-LIANG; LIU, BO; LI, XIAO-JIE; HU, KUN-PENG; ZHAO, KUN; YE, XIAO-MING

    2016-01-01

    The mammalian target of rapamycin (mTOR) is a critical mediator of the phosphoinositide 3-kinase/protein kinase B/mTOR signaling pathway, and mTOR activity is induced following heat shock. Thermotherapy is used to treat hepatocellular carcinoma (HCC). However, the role of mTOR in modulating thermosensitivity in HCC has yet to be elucidated. In the present study, the antisense plasmid pEGFP-C1-mTOR was transfected into SMMC-7721 cells, and the expression levels of mTOR were analyzed by reverse transcription-polymerase chain reaction and western blot analysis. The thermal responses of the transfected cells were also examined. The results revealed that SMMC-7721 cells were sensitive to heat treatment, and cell viability was significantly inhibited following hyperthermia treatment (P<0.01). The mRNA and protein expression levels of mTOR decreased post-transfection. Cell proliferation, colony-forming ability and motility were all significantly decreased following hyperthermia treatment in the transfected cells. Flow cytometry analysis demonstrated that apoptosis was significantly increased following treatment (P<0.01). The number of cells in S phase was increased, and the cell cycle was arrested in S phase. In conclusion, inhibition of mTOR increased the thermosensitivity of SMMC-7721 cells by increasing cellular apoptosis and inducing S phase arrest. PMID:26998020

  18. Activation of mTOR: a culprit of Alzheimer’s disease?

    PubMed Central

    Cai, Zhiyou; Chen, Guanghui; He, Wenbo; Xiao, Ming; Yan, Liang-Jun

    2015-01-01

    Alzheimer’s disease (AD) is characterized by cognitive impairment in clinical presentation, and by β-amyloid (Aβ) production and the hyper-phosphorylation of tau in basic research. More highlights demonstrate that the activation of the mammalian target of rapamycin (mTOR) enhances Aβ generation and deposition by modulating amyloid precursor protein (APP) metabolism and upregulating β- and γ-secretases. mTOR, an inhibitor of autophagy, decreases Aβ clearance by scissoring autophagy function. mTOR regulates Aβ generation or Aβ clearance by regulating several key signaling pathways, including phosphoinositide 3-kinase (PI3-K)/protein kinase B (Akt), glycogen synthase kinase 3 [GSK-3], AMP-activated protein kinase (AMPK), and insulin/insulin-like growth factor 1 (IGF-1). The activation of mTOR is also a contributor to aberrant hyperphosphorylated tau. Rapamycin, the inhibitor of mTOR, may mitigate cognitive impairment and inhibit the pathologies associated with amyloid plaques and neurofibrillary tangles by promoting autophagy. Furthermore, the upstream and downstream components of mTOR signaling are involved in the pathogenesis and progression of AD. Hence, inhibiting the activation of mTOR may be an important therapeutic target for AD. PMID:25914534

  19. A germline MTOR mutation in Aboriginal Australian siblings with intellectual disability, dysmorphism, macrocephaly, and small thoraces.

    PubMed

    Baynam, Gareth; Overkov, Angela; Davis, Mark; Mina, Kym; Schofield, Lyn; Allcock, Richard; Laing, Nigel; Cook, Matthew; Dawkins, Hugh; Goldblatt, Jack

    2015-07-01

    We report on three Aboriginal Australian siblings with a unique phenotype which overlaps with known megalencephaly syndromes and RASopathies, including Costello syndrome. A gain-of-function mutation in MTOR was identified and represents the first reported human condition due to a germline, familial MTOR mutation. We describe the findings in this family to highlight that (i) the path to determination of pathogenicity was confounded by the lack of genomic reference data for Australian Aboriginals and that (ii) the disease biology, functional analyses in this family, and studies on the tuberous sclerosis complex support consideration of an mTOR inhibitor as a therapeutic agent. PMID:25851998

  20. [Significance of mTOR (mammalian target of rapamycin) activity in human lymphomas].

    PubMed

    Márk, Ágnes

    2014-06-01

    Neoplastic processes, tumor growth, and tumor cell proliferation and survival are often due to the altered activation of different signaling pathways. The increased activity of PI3K/AKT/mTOR signaling has been shown to be an important regulator of tumor growth in several solid tumors and in mantle cell lymphomas. The active form of mTOR kinase (mammalian target of rapamycin) is a key signaling molecule, and it exists in two different complexes, mTORC1 and mTORC2. In the present work, mTOR activity was investigated in different lymphoma types, in parallel with clinical data. We also examined in Hodgkin lymphomas (HL) the role of mTOR activity in survival mechanisms such as antiapoptotic protein expression and alterations in the microenvironment. We determined which lymphoma types display characteristic high mTOR activity in our TMA (tissue microarray) study. We observed that mTOR activity is increased in mitotic lymphoid cells compared to interphasic cells. The number of diffuse large B cell lymphoma (DLBCL) and HL cases was extended in a further set of TMA. We observed significantly higher mTOR activity in the non-centrum germinativum derived subtype of DLBCL than in the centrum germinativum derived subtype, which was a prognostic marker; 63% of mTOR active cases showed Rictor overexpression, indicating mTORC2 activity. High mTOR activity was also established in 92% of HL cases, which was linked to mTORC1. This finding was not a prognostic marker, however, it can be useful in targeted therapy. We observed the overexpression of the antiapoptotic protein BCL-xL and NFκB-p50 in the majority of mTOR active HLs. HLs showed high numbers of regulatory T cells in the microenvironment and high expression of galectin-1 in tumor cells and in the extracellular matrix, when compared to reactive lymph nodes. We confirmed that mTOR inhibition had significant antiproliferative and antiapoptotic effects in lymphoma cell lines and in lymphoma xenografts (HL, DLBCL, Burkitt lymphoma

  1. Protective function of pirfenidone and everolimus on the development of chronic allograft rejection after experimental lung transplantation.

    PubMed

    von Suesskind-Schwendi, M; Heigel, E; Pfaehler, S; Haneya, A; Schmid, C; Hirt, S W; Lehle, K

    2016-07-01

    Long-term survival of lung allografts is limited by chronic rejection (CR). Oxidative stress (OxS) plays a central role in the development of CR. We investigated the influence of pirfenidone (alone or in combination with everolimus) on OxS and CR. A rat model of left lung allo-transplantation (F344-to-WKY) was used to evaluate the effects of pirfenidone alone [0,85% in chow from postoperative day (POD) -3 to 20/60] and in combination with everolimus [2,5 mg/kg bw daily from POD 7 to 20/60]. Allografts of non-treated animals, everolimus treated animals and right, non-transplanted lungs were used as references. Immunohistology of myeloperoxidase (MPO), haemoxygenase-1 (HO-1), iron and platelet-derived-growth-factor-receptor-alpha (PDGFR-a) were performed. On POD 20, all groups showed severe acute rejection (ISHLT A3-4/B1R-B2R). Groups treated with pirfenidone showed a lower interstitial inflammatory infiltration and a lower participation of highly fibrotic degenerated vessels (ISHLT-D2R). In the long term follow up (POD 60), pirfenidone alone significantly reduced chronic airway rejection (ISHLT-C; p≤0.05), interstitial fibrosis (IF; p≤0.05), content of collagen (p≤0.05), expression of PDGFR-a (p≤0.05) and the deposition of iron (p≤0.05). All groups treated with pirfenidone showed a high expression of the cytoprotective enzyme HO-1 (p≤0.05). The additional application of everolimus resulted in a significant decrease of chronic airway rejection (ISHLT-C; p≤0.05), vasculopathy (ISHLT; p≤0.05) and IF (p≤0.05). In conclusion, early application of pirfenidone inhibited the progression of CR by its anti-fibrotic and anti-oxidative properties. The additional application of an m-TOR-inhibitor increased the anti-fibrotic effects of pirfenidone which resulted in a reduction of CR after experimental LTx. PMID:26707547

  2. Immunosuppressants in cancer prevention and therapy

    PubMed Central

    Blagosklonny, Mikhail V

    2013-01-01

    Rapalogs such as rapamycin (sirolimus), everolimus, temserolimus, and deforolimus are indicated for the treatment of some malignancies. Rapamycin is the most effective cancer-preventive agent currently known, at least in mice, dramatically delaying carcinogenesis in both normal and cancer-prone murine strains. In addition, rapamycin and everolimus decrease the risk of cancer in patients receiving these drugs in the context of immunosuppressive regimens. In general, the main concern about the use of immunosuppressants in humans is an increased risk of cancer. Given that rapalogs are useful in cancer prevention and therapy, should they be viewed as immunosuppressants or immunostimulators? Or should we reconsider the role of immunity in cancer altogether? In addition to its anti-viral, anti-inflammatory, anti-angiogenic and anti-proliferative effects, rapamycin operates as a gerosuppressant, meaning that it inhibits the cellular conversion to a senescent state (the so-called geroconversion), a fundamental process involved in aging and age-related pathologies including cancer. PMID:24575379

  3. Incidence and time course of everolimus-related adverse events in postmenopausal women with hormone receptor-positive advanced breast cancer: insights from BOLERO-2

    PubMed Central

    Rugo, H. S.; Pritchard, K. I.; Gnant, M.; Noguchi, S.; Piccart, M.; Hortobagyi, G.; Baselga, J.; Perez, A.; Geberth, M.; Csoszi, T.; Chouinard, E.; Srimuninnimit, V.; Puttawibul, P.; Eakle, J.; Feng, W.; Bauly, H.; El-Hashimy, M.; Taran, T.; Burris, H. A.

    2014-01-01

    Background In the BOLERO-2 trial, everolimus (EVE), an inhibitor of mammalian target of rapamycin, demonstrated significant clinical benefit with an acceptable safety profile when administered with exemestane (EXE) in postmenopausal women with hormone receptor-positive (HR+) advanced breast cancer. We report on the incidence, time course, severity, and resolution of treatment-emergent adverse events (AEs) as well as incidence of dose modifications during the extended follow-up of this study. Patients and methods Patients were randomized (2:1) to receive EVE 10 mg/day or placebo (PBO), with open-label EXE 25 mg/day (n = 724). The primary end point was progression-free survival. Secondary end points included overall survival, objective response rate, and safety. Safety evaluations included recording of AEs, laboratory values, dose interruptions/adjustments, and study drug discontinuations. Results The safety population comprised 720 patients (EVE + EXE, 482; PBO + EXE, 238). The median follow-up was 18 months. Class-effect toxicities, including stomatitis, pneumonitis, and hyperglycemia, were generally of mild or moderate severity and occurred relatively early after treatment initiation (except pneumonitis); incidence tapered off thereafter. EVE dose reduction and interruption (360 and 705 events, respectively) required for AE management were independent of patient age. The median duration of dose interruption was 7 days. Discontinuation of both study drugs because of AEs was higher with EVE + EXE (9%) versus PBO + EXE (3%). Conclusions Most EVE-associated AEs occur soon after initiation of therapy, are typically of mild or moderate severity, and are generally manageable with dose reduction and interruption. Discontinuation due to toxicity was uncommon. Understanding the time course of class-effect AEs will help inform preventive and monitoring strategies as well as patient education. Trial registration number NCT00863655. PMID:24615500

  4. Place of mTOR inhibitors in management of BKV infection after kidney transplantation

    PubMed Central

    Jouve, Thomas; Rostaing, Lionel; Malvezzi, Paolo

    2016-01-01

    Context: BK virus (BKV) viremia and BKV-associated nephropathy (BKVAN) have become a serious nuisance to kidney transplant (KT) patients since the mid-nineties, when the incidence of this disease has increased significantly. Evidence Acquisition: Directory of open access journals (DOAJ), EMBASE, Google Scholar, PubMed, EBSCO, and Web of Science have been searched. Results: Many hypothesis have been made as to why this phenomenon has developed; it is of general opinion that a more potent immunosuppression is at the core of the problem. The use of the association of tacrolimus (TAC) with mycophenolic acid (MPA) has gained momentum in the same years as the increase in BKV viremia incidence making it seem to be the most likely culprit. m-TOR inhibitors (m-TORIs) have been shown to have antiviral properties in vitro and this fact has encouraged different transplant teams to use these agents when confronted with BKV infection (viremia or nephropathy). However, the results are mitigated. There had been conflicting results for example when converting from TAC-to sirolimus-based immunosuppression in the setting of established BKVAN. Conclusions: In order to prevent BKV infection we have to minimize to some extent immunosuppression, but it is not always possible, e.g. in high immunological risk patients. Conversely, we could use m-TORIs associated with low-dose calcineurin inhibitors (CNIs). This could be actually the key to a safe immunosuppression regimen both from the immunological stand point and from the viral one. PMID:27047803

  5. Inhibition of mTOR Reduces Anal Carcinogenesis in Transgenic Mouse Model

    PubMed Central

    Zhang, Wei; Hall, Bradford; Bian, Yansong; Kulkarni, Ashok B.

    2013-01-01

    The molecular mechanism of human anal squamous cell carcinoma (ASCC) is unclear, and the accumulating evidence indicate association of ASCC with the activation of the Akt/mTOR pathway. Here we describe a mouse model with spontaneous anal squamous cell cancer, wherein a combined deletion of Tgfbr1 and Pten in stratified squamous epithelia was induced using inducible K14-Cre. Histopathologic analyses confirmed that 33.3% of the mice showed increased susceptibility to ASCC and precancerous lesions. Biomarker analyses demonstrated that the activation of the Akt pathway in ASCC of the Tgfbr1 and Pten double knockout (2cKO) mouse was similar to that observed in human anal cancer. Chemopreventive experiments using mTOR inhibitor-rapamycin treatment significantly delayed the onset of the ASCC tumors and reduced the tumor burden in 2cKO mice by decreasing the phosphorylation of Akt and S6. This is the first conditional knockout mouse model used for investigating the contributions of viral and cellular factors in anal carcinogenesis without carcinogen-mediated induction, and it would provide a platform for assessing new therapeutic modalities for treating and/or preventing this type of cancer. PMID:24124460

  6. Adapting the Stress Response: Viral Subversion of the mTOR Signaling Pathway.

    PubMed

    Le Sage, Valerie; Cinti, Alessandro; Amorim, Raquel; Mouland, Andrew J

    2016-01-01

    The mammalian target of rapamycin (mTOR) is a central regulator of gene expression, translation and various metabolic processes. Multiple extracellular (growth factors) and intracellular (energy status) molecular signals as well as a variety of stressors are integrated into the mTOR pathway. Viral infection is a significant stress that can activate, reduce or even suppress the mTOR signaling pathway. Consequently, viruses have evolved a plethora of different mechanisms to attack and co-opt the mTOR pathway in order to make the host cell a hospitable environment for replication. A more comprehensive knowledge of different viral interactions may provide fruitful targets for new antiviral drugs. PMID:27231932

  7. mTOR, metabolism, and the regulation of T-cell differentiation and function

    PubMed Central

    Waickman, Adam T; Powell, Jonathan D.

    2012-01-01

    Summary Upon antigen recognition, naive T cells undergo rapid expansion and activation. The energy requirements for this expansion are formidable, and T-cell activation is accompanied by dramatic changes in cellular metabolism. Furthermore, the outcome of antigen engagement is guided by multiple cues derived from the immune microenvironment. Mammalian target of rapamycin (mTOR) is emerging as a central integrator of these signals playing a critical role in driving T-cell differentiation and function. Indeed, multiple metabolic programs are controlled by mTOR signaling. In this review, we discuss the role of mTOR in regulating metabolism and how these pathways intersect with the ability of mTOR to integrate cues that guide the outcome of T-cell receptor engagement. PMID:22889214

  8. Adapting the Stress Response: Viral Subversion of the mTOR Signaling Pathway

    PubMed Central

    Le Sage, Valerie; Cinti, Alessandro; Amorim, Raquel; Mouland, Andrew J.

    2016-01-01

    The mammalian target of rapamycin (mTOR) is a central regulator of gene expression, translation and various metabolic processes. Multiple extracellular (growth factors) and intracellular (energy status) molecular signals as well as a variety of stressors are integrated into the mTOR pathway. Viral infection is a significant stress that can activate, reduce or even suppress the mTOR signaling pathway. Consequently, viruses have evolved a plethora of different mechanisms to attack and co-opt the mTOR pathway in order to make the host cell a hospitable environment for replication. A more comprehensive knowledge of different viral interactions may provide fruitful targets for new antiviral drugs. PMID:27231932

  9. mTOR Regulation of Lymphoid Cells in Immunity to Pathogens

    PubMed Central

    Keating, Rachael; McGargill, Maureen Ann

    2016-01-01

    Immunity to pathogens exists as a fine balance between promoting activation and expansion of effector cells, while simultaneously limiting normal and aberrant responses. These seemingly opposing functions are kept in check by immune regulators. The mechanistic target of rapamycin (mTOR) is a serine/threonine kinase that senses nutrient availability and, in turn, regulates cell metabolism, growth, and survival accordingly. mTOR plays a pivotal role in facilitating immune defense against invading pathogens by regulating the differentiation, activation, and effector functions of lymphoid cells. Here, we focus on the emerging and sometimes contradictory roles of mTOR in orchestrating lymphoid cell-mediated host immune responses to pathogens. A thorough understanding of how mTOR impacts lymphoid cells in pathogen defense will provide the necessary base for developing therapeutic interventions for infectious diseases. PMID:27242787

  10. mTOR Regulation of Lymphoid Cells in Immunity to Pathogens.

    PubMed

    Keating, Rachael; McGargill, Maureen Ann

    2016-01-01

    Immunity to pathogens exists as a fine balance between promoting activation and expansion of effector cells, while simultaneously limiting normal and aberrant responses. These seemingly opposing functions are kept in check by immune regulators. The mechanistic target of rapamycin (mTOR) is a serine/threonine kinase that senses nutrient availability and, in turn, regulates cell metabolism, growth, and survival accordingly. mTOR plays a pivotal role in facilitating immune defense against invading pathogens by regulating the differentiation, activation, and effector functions of lymphoid cells. Here, we focus on the emerging and sometimes contradictory roles of mTOR in orchestrating lymphoid cell-mediated host immune responses to pathogens. A thorough understanding of how mTOR impacts lymphoid cells in pathogen defense will provide the necessary base for developing therapeutic interventions for infectious diseases. PMID:27242787

  11. Response to everolimus is seen in TSC-associated SEGAs and angiomyolipomas independent of mutation type and site in TSC1 and TSC2

    PubMed Central

    Kwiatkowski, David J; Palmer, Michael R; Jozwiak, Sergiusz; Bissler, John; Franz, David; Segal, Scott; Chen, David; Sampson, Julian R

    2015-01-01

    Tuberous sclerosis complex is an autosomal dominant disorder that occurs owing to inactivating mutations in either TSC1 or TSC2. Tuberous sclerosis complex-related tumors in the brain, such as subependymal giant cell astrocytoma, and in the kidney, such as angiomyolipoma, can cause significant morbidity and mortality. Recently, randomized clinical trials (EXIST-1 and EXIST-2) of everolimus for each of these tuberous sclerosis complex-associated tumors demonstrated the benefit of this drug, which blocks activated mammalian target of rapamycin complex 1. Here we report on the spectrum of mutations seen in patients treated during these trials and the association between mutation and response. TSC2 mutations were predominant among patients in both trials and were present in nearly all subjects with angiomyolipoma in whom a mutation was identified (97%), whereas TSC1 mutations were rare in those subjects (3%). The spectrum of mutations seen in each gene was similar to those previously reported. In both trials, there was no apparent association between mutation type or location within each gene and response to everolimus. Everolimus responses were also seen at a similar frequency for the 16–18% of patients in each trial in whom no mutation in either gene was identified. These observations confirm the strong association between TSC2 mutation and angiomyolipoma burden seen in previous studies, and they indicate that everolimus response occurs regardless of mutation type or location or when no mutation in TSC1 or TSC2 has been identified. PMID:25782670

  12. Pre-treatment neutrophil-to-lymphocyte ratio may be associated with the outcome in patients treated with everolimus for metastatic renal cell carcinoma

    PubMed Central

    Santoni, M; De Giorgi, U; Iacovelli, R; Conti, A; Burattini, L; Rossi, L; Luca Burgio, S; Berardi, R; Muzzonigro, G; Cortesi, E; Amadori, D; Cascinu, S

    2013-01-01

    Background: Everolimus is a mammalian target of rapamycin inhibitor approved for the treatment of metastatic renal cell carcinoma (mRCC). We aimed to assess the association between pre-treatment neutrophil-to-lymphocyte ratio (NLR) and the outcome of patients treated with everolimus for mRCC. Methods: Ninety-seven patients with mRCC were treated with everolimus till April 2013 in our institutions. Patients were stratified in two groups with NLR >3 (Group A) vs <3 (Group B). Progression-free survival (PFS) and overall survival (OS) were estimated using Kaplan–Meier method. Gender, age, Motzer prognostic group, PFS on first-line therapy, neutrophilia and NLR were included in the Cox analysis to investigate their prognostic relevance. Results: Median OS and PFS were 10.6 and 5.3 months, respectively. Median OS was 12.2 months in Group A and 24.4 months in Group B (P=0.001). Median PFS was 3.4 months in Group A and 9.9 months in Group B (P<0.001). At multivariate analysis, only Motzer prognostic group and NLR were independent prognostic factors for OS and PFS. Conclusion: Pre-treatment NLR is an independent prognostic factor for patients with mRCC treated with second- or third-line everolimus. This should be investigated and validated in prospective studies. PMID:24008663

  13. DEPTOR-related mTOR suppression is involved in metformin's anti-cancer action in human liver cancer cells

    SciTech Connect

    Obara, Akio; Fujita, Yoshihito; Abudukadier, Abulizi; Fukushima, Toru; Oguri, Yasuo; Ogura, Masahito; Harashima, Shin-ichi; Hosokawa, Masaya; Inagaki, Nobuya

    2015-05-15

    Metformin, one of the most commonly used drugs for patients with type 2 diabetes, recently has received much attention regarding its anti-cancer action. It is thought that the suppression of mTOR signaling is involved in metformin's anti-cancer action. Although liver cancer is one of the most responsive types of cancer for reduction of incidence by metformin, the molecular mechanism of the suppression of mTOR in liver remains unknown. In this study, we investigated the mechanism of the suppressing effect of metformin on mTOR signaling and cell proliferation using human liver cancer cells. Metformin suppressed phosphorylation of p70-S6 kinase, and ribosome protein S6, downstream targets of mTOR, and suppressed cell proliferation. We found that DEPTOR, an endogenous substrate of mTOR suppression, is involved in the suppressing effect of metformin on mTOR signaling and cell proliferation in human liver cancer cells. Metformin increases the protein levels of DEPTOR, intensifies binding to mTOR, and exerts a suppressing effect on mTOR signaling. This increasing effect of DEPTOR by metformin is regulated by the proteasome degradation system; the suppressing effect of metformin on mTOR signaling and cell proliferation is in a DEPTOR-dependent manner. Furthermore, metformin exerts a suppressing effect on proteasome activity, DEPTOR-related mTOR signaling, and cell proliferation in an AMPK-dependent manner. We conclude that DEPTOR-related mTOR suppression is involved in metformin's anti-cancer action in liver, and could be a novel target for anti-cancer therapy. - Highlights: • We elucidated a novel pathway of metformin's anti-cancer action in HCC cells. • DEPTOR is involved in the suppressing effect of metformin on mTOR signaling. • Metformin increases DEPTOR protein levels via suppression of proteasome activity. • DEPTOR-related mTOR suppression is involved in metformin's anti-cancer action.

  14. mTOR regulates tau phosphorylation and degradation: implications for Alzheimer's disease and other tauopathies.

    PubMed

    Caccamo, Antonella; Magrì, Andrea; Medina, David X; Wisely, Elena V; López-Aranda, Manuel F; Silva, Alcino J; Oddo, Salvatore

    2013-06-01

    Accumulation of tau is a critical event in several neurodegenerative disorders, collectively known as tauopathies, which include Alzheimer's disease and frontotemporal dementia. Pathological tau is hyperphosphorylated and aggregates to form neurofibrillary tangles. The molecular mechanisms leading to tau accumulation remain unclear and more needs to be done to elucidate them. Age is a major risk factor for all tauopathies, suggesting that molecular changes contributing to the aging process may facilitate tau accumulation and represent common mechanisms across different tauopathies. Here, we use multiple animal models and complementary genetic and pharmacological approaches to show that the mammalian target of rapamycin (mTOR) regulates tau phosphorylation and degradation. Specifically, we show that genetically increasing mTOR activity elevates endogenous mouse tau levels and phosphorylation. Complementary to it, we further demonstrate that pharmacologically reducing mTOR signaling with rapamycin ameliorates tau pathology and the associated behavioral deficits in a mouse model overexpressing mutant human tau. Mechanistically, we provide compelling evidence that the association between mTOR and tau is linked to GSK3β and autophagy function. In summary, we show that increasing mTOR signaling facilitates tau pathology, while reducing mTOR signaling ameliorates tau pathology. Given the overwhelming evidence that reducing mTOR signaling increases lifespan and healthspan, the data presented here have profound clinical implications for aging and tauopathies and provide the molecular basis for how aging may contribute to tau pathology. Additionally, these results provide preclinical data indicating that reducing mTOR signaling may be a valid therapeutic approach for tauopathies. PMID:23425014

  15. YAP enters the mTOR pathway to promote tuberous sclerosis complex

    PubMed Central

    Liang, Ning; Pende, Mario

    2015-01-01

    Mutations in tuberous sclerosis complex 1 (TSC1) or TSC2 predispose to angiomyolipomas and lymphangioleiomyomatosis in a mTOR-dependent manner. In these mesenchymal lesions, mTOR suppresses macroautophagy-mediated lysosomal degradation of YAP, which is a transcriptional coactivator of Hippo pathway and is required for the tumorigenesis of TSC. Therapeutic applications for TSC and other diseases with dysregulated mTOR activity can be envisaged. PMID:27308518

  16. 2-Deoxy-D-glucose Sensitizes Cancer Cells to Barasertib and Everolimus by ROS-independent Mechanism(s).

    PubMed

    Zhelev, Zhivko; Ivanova, Donika; Aoki, Ichio; Saga, Tsuneo; Bakalova, Rumiana

    2015-12-01

    The aim of the present study was to investigate: (i) the possibility of sensitizing cancer cells to anticancer drugs using the redox modulator 2-deoxy-D-glucose (2-DDG); (ii) to find such combinations with synergistic cytotoxic effect; (iii) and to clarify the role of reactive oxygen species (ROS) for induction of apoptosis and cytotoxicity through these combinations. The study covers 15 anticancer drugs--both conventional and new-generation. Four parameters were analyzed simultaneously in Jurkat leukemia cells, treated by drugs or 2-DDG (separately or in combination): cell viability, induction of apoptosis, levels of ROS, and level of protein-carbonyl products. Very well-expressed synergistic cytotoxic effects were found after 48-h treatment of Jurkat cells with 2-DDG in combination with: palbociclib, everolimus, lonafarnib, bortezomib, and barasertib. The synergistic cytotoxic effect of everolimus with 2-DDG was accompanied by very strong induction of apoptosis in cells, but a very strong reduction of ROS level. Changes in the levels of protein-carbonyl products were not detected. The synergistic cytotoxic effect of barasertib with 2-DDG was accompanied by very strong induction of apoptosis in cells, without any increase of ROS levels, but with an enhancement of protein-carbonyl products. PMID:26637878

  17. REDD2-mediated inhibition of mTOR promotes dendrite retraction induced by axonal injury.

    PubMed

    Morquette, B; Morquette, P; Agostinone, J; Feinstein, E; McKinney, R A; Kolta, A; Di Polo, A

    2015-04-01

    Dendritic defects occur in neurodegenerative diseases accompanied by axonopathy, yet the mechanisms that regulate these pathologic changes are poorly understood. Using Thy1-YFPH mice subjected to optic nerve axotomy, we demonstrate early retraction of retinal ganglion cell (RGC) dendrites and selective loss of mammalian target of rapamycin (mTOR) activity, which precede soma loss. Axonal injury triggered rapid upregulation of the stress-induced protein REDD2 (regulated in development and DNA damage response 2), a potent inhibitor of mTOR. Short interfering RNA-mediated REDD2 knockdown restored mTOR activity and rescued dendritic length, area and branch complexity in a rapamycin-dependent manner. Whole-cell recordings demonstrated that REDD2 depletion leading to mTOR activation in RGCs restored their light response properties. Lastly, we show that REDD2-dependent mTOR activity extended RGC survival following axonal damage. These results indicate that injury-induced stress leads to REDD2 upregulation, mTOR inhibition and dendrite pathology causing neuronal dysfunction and subsequent cell death. PMID:25257176

  18. Hyperactive mTOR pathway promotes lymphoproliferation and abnormal differentiation in autoimmune lymphoproliferative syndrome.

    PubMed

    Völkl, Simon; Rensing-Ehl, Anne; Allgäuer, Andrea; Schreiner, Elisabeth; Lorenz, Myriam Ricarda; Rohr, Jan; Klemann, Christian; Fuchs, Ilka; Schuster, Volker; von Bueren, André O; Naumann-Bartsch, Nora; Gambineri, Eleonora; Siepermann, Kathrin; Kobbe, Robin; Nathrath, Michaela; Arkwright, Peter D; Miano, Maurizio; Stachel, Klaus-Daniel; Metzler, Markus; Schwarz, Klaus; Kremer, Anita N; Speckmann, Carsten; Ehl, Stephan; Mackensen, Andreas

    2016-07-14

    Autoimmune lymphoproliferative syndrome (ALPS) is a human disorder characterized by defective Fas signaling, resulting in chronic benign lymphoproliferation and accumulation of TCRαβ(+) CD4(-) CD8(-) double-negative T (DNT) cells. Although their phenotype resembles that of terminally differentiated or exhausted T cells, lack of KLRG1, high eomesodermin, and marginal T-bet expression point instead to a long-lived memory state with potent proliferative capacity. Here we show that despite their terminally differentiated phenotype, human ALPS DNT cells exhibit substantial mitotic activity in vivo. Notably, hyperproliferation of ALPS DNT cells is associated with increased basal and activation-induced phosphorylation of serine-threonine kinases Akt and mechanistic target of rapamycin (mTOR). The mTOR inhibitor rapamycin abrogated survival and proliferation of ALPS DNT cells, but not of CD4(+) or CD8(+) T cells in vitro. In vivo, mTOR inhibition reduced proliferation and abnormal differentiation by DNT cells. Importantly, increased mitotic activity and hyperactive mTOR signaling was also observed in recently defined CD4(+) or CD8(+) precursor DNT cells, and mTOR inhibition specifically reduced these cells in vivo, indicating abnormal programming of Fas-deficient T cells before the DNT stage. Thus, our results identify the mTOR pathway as a major regulator of lymphoproliferation and aberrant differentiation in ALPS. PMID:27099149

  19. mTOR disruption causes intestinal epithelial cell defects and intestinal atrophy postinjury in mice.

    PubMed

    Sampson, Leesa L; Davis, Ashley K; Grogg, Matthew W; Zheng, Yi

    2016-03-01

    Intestinal stem cells (ISCs) drive small intestinal epithelial homeostasis and regeneration. Mechanistic target of rapamycin (mTOR) regulates stem and progenitor cell metabolism and is frequently dysregulated in human disease, but its physiologic functions in the mammalian small intestinal epithelium remain poorly defined. We disrupted the genes mTOR, Rptor, Rictor, or both Rptor and Rictor in mouse ISCs, progenitors, and differentiated intestinal epithelial cells (IECs) using Villin-Cre. Mutant tissues and wild-type or heterozygous littermate controls were analyzed by histologic immunostaining, immunoblots, and proliferation assays. A total of 10 Gy irradiation was used to injure the intestinal epithelium and induce subsequent crypt regeneration. We report that mTOR supports absorptive enterocytes and secretory Paneth and goblet cell function while negatively regulating chromogranin A-positive enteroendocrine cell number. Through additional Rptor, Rictor, and Rptor/Rictor mutant mouse models, we identify mechanistic target of rapamycin complex 1 as the major IEC regulatory pathway, but mechanistic target of rapamycin complex 2 also contributes to ileal villus maintenance and goblet cell size. Homeostatic adult small intestinal crypt cell proliferation, survival, and canonical wingless-int (WNT) activity are not mTOR dependent, but Olfm4(+) ISC/progenitor population maintenance and crypt regeneration postinjury require mTOR. Overall, we conclude that mTOR regulates multiple IEC lineages and promotes stem and progenitor cell activity during intestinal epithelium repair postinjury. PMID:26631481

  20. mTOR controls lysosome tubulation and antigen presentation in macrophages and dendritic cells

    PubMed Central

    Saric, Amra; Hipolito, Victoria E. B.; Kay, Jason G.; Canton, Johnathan; Antonescu, Costin N.; Botelho, Roberto J.

    2016-01-01

    Macrophages and dendritic cells exposed to lipopolysaccharide (LPS) convert their lysosomes from small, punctate organelles into a network of tubules. Tubular lysosomes have been implicated in phagosome maturation, retention of fluid phase, and antigen presentation. There is a growing appreciation that lysosomes act as sensors of stress and the metabolic state of the cell through the kinase mTOR. Here we show that LPS stimulates mTOR and that mTOR is required for LPS-induced lysosome tubulation and secretion of major histocompatibility complex II in macrophages and dendritic cells. Specifically, we show that the canonical phosphatidylinositol 3-kinase–Akt–mTOR signaling pathway regulates LPS-induced lysosome tubulation independently of IRAK1/4 and TBK. Of note, we find that LPS treatment augmented the levels of membrane-associated Arl8b, a lysosomal GTPase required for tubulation that promotes kinesin-dependent lysosome movement to the cell periphery, in an mTOR-dependent manner. This suggests that mTOR may interface with the Arl8b-kinesin machinery. To further support this notion, we show that mTOR antagonists can block outward movement of lysosomes in cells treated with acetate but have no effect in retrograde movement upon acetate removal. Overall our work provides tantalizing evidence that mTOR plays a role in controlling lysosome morphology and trafficking by modulating microtubule-based motor activity in leukocytes. PMID:26582390

  1. Periostin Responds to Mechanical Stress and Tension by Activating the MTOR Signaling Pathway

    PubMed Central

    Rosselli-Murai, Luciana K.; Galindo-Moreno, Pablo; Padial-Molina, Miguel; Volk, Sarah L.; Murai, Marcelo J.; Rios, Hector F.; Squarize, Cristiane H.; Castilho, Rogerio M.

    2013-01-01

    Current knowledge about Periostin biology has expanded from its recognized functions in embryogenesis and bone metabolism to its roles in tissue repair and remodeling and its clinical implications in cancer. Emerging evidence suggests that Periostin plays a critical role in the mechanism of wound healing; however, the paracrine effect of Periostin in epithelial cell biology is still poorly understood. We found that epithelial cells are capable of producing endogenous Periostin that, unlike mesenchymal cell, cannot be secreted. Epithelial cells responded to Periostin paracrine stimuli by enhancing cellular migration and proliferation and by activating the mTOR signaling pathway. Interestingly, biomechanical stimulation of epithelial cells, which simulates tension forces that occur during initial steps of tissue healing, induced Periostin production and mTOR activation. The molecular association of Periostin and mTOR signaling was further dissected by administering rapamycin, a selective pharmacological inhibitor of mTOR, and by disruption of Raptor and Rictor scaffold proteins implicated in the regulation of mTORC1 and mTORC2 complex assembly. Both strategies resulted in ablation of Periostin-induced mitogenic and migratory activity. These results indicate that Periostin-induced epithelial migration and proliferation requires mTOR signaling. Collectively, our findings identify Periostin as a mechanical stress responsive molecule that is primarily secreted by fibroblasts during wound healing and expressed endogenously in epithelial cells resulting in the control of cellular physiology through a mechanism mediated by the mTOR signaling cascade. PMID:24349533

  2. mTOR controls lysosome tubulation and antigen presentation in macrophages and dendritic cells.

    PubMed

    Saric, Amra; Hipolito, Victoria E B; Kay, Jason G; Canton, Johnathan; Antonescu, Costin N; Botelho, Roberto J

    2016-01-15

    Macrophages and dendritic cells exposed to lipopolysaccharide (LPS) convert their lysosomes from small, punctate organelles into a network of tubules. Tubular lysosomes have been implicated in phagosome maturation, retention of fluid phase, and antigen presentation. There is a growing appreciation that lysosomes act as sensors of stress and the metabolic state of the cell through the kinase mTOR. Here we show that LPS stimulates mTOR and that mTOR is required for LPS-induced lysosome tubulation and secretion of major histocompatibility complex II in macrophages and dendritic cells. Specifically, we show that the canonical phosphatidylinositol 3-kinase-Akt-mTOR signaling pathway regulates LPS-induced lysosome tubulation independently of IRAK1/4 and TBK. Of note, we find that LPS treatment augmented the levels of membrane-associated Arl8b, a lysosomal GTPase required for tubulation that promotes kinesin-dependent lysosome movement to the cell periphery, in an mTOR-dependent manner. This suggests that mTOR may interface with the Arl8b-kinesin machinery. To further support this notion, we show that mTOR antagonists can block outward movement of lysosomes in cells treated with acetate but have no effect in retrograde movement upon acetate removal. Overall our work provides tantalizing evidence that mTOR plays a role in controlling lysosome morphology and trafficking by modulating microtubule-based motor activity in leukocytes. PMID:26582390

  3. The role of mTOR signalling in neurogenesis, insights from tuberous sclerosis complex.

    PubMed

    Tee, Andrew R; Sampson, Julian R; Pal, Deb K; Bateman, Joseph M

    2016-04-01

    Understanding the development and function of the nervous system is one of the foremost aims of current biomedical research. The nervous system is generated during a relatively short period of intense neurogenesis that is orchestrated by a number of key molecular signalling pathways. Even subtle defects in the activity of these molecules can have serious repercussions resulting in neurological, neurodevelopmental and neurocognitive problems including epilepsy, intellectual disability and autism. Tuberous sclerosis complex (TSC) is a monogenic disease characterised by these problems and by the formation of benign tumours in multiple organs, including the brain. TSC is caused by mutations in the TSC1 or TSC2 gene leading to activation of the mechanistic target of rapamycin (mTOR) signalling pathway. A desire to understand the neurological manifestations of TSC has stimulated research into the role of the mTOR pathway in neurogenesis. In this review we describe TSC neurobiology and how the use of animal model systems has provided insights into the roles of mTOR signalling in neuronal differentiation and migration. Recent progress in this field has identified novel mTOR pathway components regulating neuronal differentiation. The roles of mTOR signalling and aberrant neurogenesis in epilepsy are also discussed. Continuing efforts to understand mTOR neurobiology will help to identify new therapeutic targets for TSC and other neurological diseases. PMID:26849906

  4. PAR-1, -4, and the mTOR Pathway Following Germinal Matrix Hemorrhage.

    PubMed

    Lekic, Tim; Krafft, Paul R; Klebe, Damon; Flores, Jerry; Rolland, William B; Tang, Jiping; Zhang, John H

    2016-01-01

    Germinal matrix hemorrhage (GMH) is the most common cause of neurological complications of prematurity and has lasting implications. PAR-1 and PAR-4 receptors are involved with upstream signaling pathways following brain hemorrhage in adult models of stroke, of which the mammalian target of rapamycin (mTOR) is a potential downstream mediator. Therefore, we hypothesized a role for PAR-1, -4/ mTOR signaling following GMH brain injury. Postnatal day 7 Sprague-Dawley rats were subjected to GMH through stereotactic infusion of collagenase into the right ganglionic eminence. Rodents were euthanized at 72 h (short term), or 4 weeks (long term). Short-term mTOR expression was evaluated by Western blot in the context of PAR-1 (SCH-79797) and PAR-4 (P4pal10) inhibition. Pups in the long-term group were administered the selective mTOR inhibitor (rapamycin) with neurobehavioral and brain pathological examinations performed at 4 weeks. Pharmacological PAR-1, -4 antagonism normalized the increased mTOR expression following GMH. Early inhibition of mTOR by rapamycin improved long-term outcomes in rats. Mammalian-TOR signaling plays an important role in brain injury following neonatal GMH, possibly involving upstream PAR-1, -4 mechanisms. PMID:26463951

  5. Role of mTOR Downstream Effector Signaling Molecules in Francisella Tularensis Internalization by Murine Macrophages

    PubMed Central

    Edwards, Michael W.; Aultman, James A.; Harber, Gregory; Bhatt, Jay M.; Sztul, Elizabeth; Xu, Qingan; Zhang, Ping; Michalek, Suzanne M.; Katz, Jannet

    2013-01-01

    Francisella tularensis is an infectious, gram-negative, intracellular microorganism, and the cause of tularemia. Invasion of host cells by intracellular pathogens like Francisella is initiated by their interaction with different host cell membrane receptors and the rapid phosphorylation of different downstream signaling molecules. PI3K and Syk have been shown to be involved in F. tularensis host cell entry, and both of these signaling molecules are associated with the master regulator serine/threonine kinase mTOR; yet the involvement of mTOR in F. tularensis invasion of host cells has not been assessed. Here, we report that infection of macrophages with F. tularensis triggers the phosphorylation of mTOR downstream effector molecules, and that signaling via TLR2 is necessary for these events. Inhibition of mTOR or of PI3K, ERK, or p38, but not Akt signaling, downregulates the levels of phosphorylation of mTOR downstream targets, and significantly reduces the number of F. tularensis cells invading macrophages. Moreover, while phosphorylation of mTOR downstream effectors occurs via the PI3K pathway, it also involves PLCγ1 and Ca2+ signaling. Furthermore, abrogation of PLC or Ca2+ signaling revealed their important role in the ability of F. tularensis to invade host cells. Together, these findings suggest that F. tularensis invasion of primary macrophages utilize a myriad of host signaling pathways to ensure effective cell entry. PMID:24312679

  6. Targeting mTOR in RET mutant medullary and differentiated thyroid cancer cells

    PubMed Central

    Gild, Matti L; Landa, Iñigo; Ryder, Mabel; Ghossein, Ronald A; Knauf, Jeffrey A; Fagin, James A

    2015-01-01

    Inhibitors of RET, a tyrosine kinase receptor encoded by a gene that is frequently mutated in medullary thyroid cancer, have emerged as promising novel therapies for the disease. Rapalogs and other mammalian target of rapamycin (mTOR) inhibitors are effective agents in patients with gastroenteropancreatic neuroendocrine tumors, which share lineage properties with medullary thyroid carcinomas. The objective of this study was to investigate the contribution of mTOR activity to RET-induced signaling and cell growth and to establish whether growth suppression is enhanced by co-targeting RET and mTOR kinase activities. Treatment of the RET mutant cell lines TT, TPC-1, and MZ-CRC-1 with AST487, a RET kinase inhibitor, suppressed growth and showed profound and sustained inhibition of mTOR signaling, which was recapitulated by siRNA-mediated RET knockdown. Inhibition of mTOR with INK128, a dual mTORC1 and mTORC2 kinase inhibitor, also resulted in marked growth suppression to levels similar to those seen with RET blockade. Moreover, combined treatment with AST487 and INK128 at low concentrations suppressed growth and induced apoptosis. These data establish mTOR as a key mediator of RET-mediated cell growth in thyroid cancer cells and provide a rationale for combinatorial treatments in thyroid cancers with oncogenic RET mutations. PMID:23828865

  7. Activation of mammalian target of rapamycin (mTOR) in triple negative feline mammary carcinomas

    PubMed Central

    2013-01-01

    Background Triple negative breast cancer (TNBC) in humans is defined by the absence of oestrogen receptor (ER), progesterone receptor (PR) and HER2 overexpression. Mammalian target of rapamycin (mTOR) is overexpressed in TNBC and it represents a potential target for the treatment of this aggressive tumour. Feline mammary carcinoma (FMC) is considered to be a model for hormone-independent human breast cancer. This study investigated mTOR and p-mTOR expression in FMC in relation to triple negative (TN) phenotype. Results The expression of mTOR, p-mTOR, ERα, PR and HER2 was evaluated in 58 FMCs by immunohistochemistry and in six FMC cell lines by Western blot analysis. 53.5% of FMC analyzed were ER, PR, HER2 negative (TN-FMC) while 56.9% and 55.2% of cases expressed mTOR and p-mTOR respectively. In this study we found that m-TOR and p-mTOR were more frequently detected in TN-FMC and in HER2 negative samples. Conclusions In this study, we demonstrate that there is also a FMC subset defined as TN FMC, which is characterised by a statistically significant association with m-TOR and p-mTOR expression as demonstrated in human breast cancer. PMID:23587222

  8. Biodegradable-Polymer Biolimus-Eluting Stents versus Durable-Polymer Everolimus-Eluting Stents at One-Year Follow-Up: A Registry-Based Cohort Study.

    PubMed

    Parsa, Ehsan; Saroukhani, Sepideh; Majlessi, Fereshteh; Poorhosseini, Hamidreza; Lofti-Tokaldany, Masoumeh; Jalali, Arash; Salarifar, Mojtaba; Nematipour, Ebrahim; Alidoosti, Mohammad; Aghajani, Hassan; Amirzadegan, Alireza; Kassaian, Seyed Ebrahim

    2016-04-01

    We compared outcomes of percutaneous coronary intervention patients who received biodegradable-polymer biolimus-eluting stents with those who received durable-polymer everolimus-eluting stents. At Tehran Heart Center, we performed a retrospective analysis of the data from January 2007 through December 2011 on 3,270 consecutive patients with coronary artery disease who underwent percutaneous coronary intervention with the biodegradable-polymer biolimus-eluting stent or the durable-polymer everolimus-eluting stent. We excluded patients with histories of coronary artery bypass grafting or percutaneous coronary intervention, acute ST-segment-elevation myocardial infarction, or the implantation of 2 different stent types. Patients were monitored for 12 months. The primary endpoint was a major adverse cardiac event, defined as a composite of death, nonfatal myocardial infarction, and target-vessel and target-lesion revascularization. Durable-polymer everolimus-eluting stents were implanted in 2,648 (81%) and biodegradable-polymer biolimus-eluting stents in 622 (19%) of the study population. There was no significant difference between the 2 groups (2.7% vs 2.7%; P=0.984) in the incidence of major adverse cardiac events. The cumulative adjusted probability of major adverse cardiac events in the biodegradable-polymer biolimus-eluting stent group did not differ from that of such events in the durable-polymer everolimus-eluting stent group (hazard ratio=0.768; 95% confidence interval, 0.421-1.44; P=0.388). We conclude that in our patients the biodegradable-polymer biolimus-eluting stent was as effective and safe, during the 12-month follow-up period, as was the durable-polymer everolimus-eluting stent. PMID:27127426

  9. The Synergistic Effect of Everolimus and Chloroquine on Endothelial Cell Number Reduction Is Paralleled by Increased Apoptosis and Reduced Autophagy Occurrence

    PubMed Central

    Grimaldi, Anna; Balestrieri, Maria Luisa; D'Onofrio, Nunzia; Di Domenico, Gilda; Nocera, Cosimo; Lamberti, Monica; Tonini, Giuseppe; Zoccoli, Alice; Santini, Daniele; Caraglia, Michele; Pantano, Francesco

    2013-01-01

    Endothelial Progenitor Cells (EPCs), a minor subpopulation of the mononuclear cell fraction in peripheral blood, play a critical role in cancer development as they contribute to angiogenesis-mediated pathological neovascularization. In response to tumor cytokines, including VEGF, EPCs mobilize from the bone marrow into the peripheral circulation and move to the tumor bed where they incorporate into sprouting neovessels. In the present study, we evaluated the effects of everolimus (Afinitor, Novartis), a rapamycin analogue, alone or in combination with chloroquine, a 4-alkylamino substituted quinoline family member, one of the autophagy inhibitors, on EPCs biological functions. We found that either everolimus or chloroquine induce growth inhibition on EPCs in a dose-dependent manner after 72 h from the beginning of incubation. The combined administration of the two drugs to EPC was synergistic in inducing growth inhibition; in details, the maximal pharmacological synergism between everolimus and chloroquine in inducing growth inhibition on EPCs cells was recorded when chloroquine was administered 24 h before everolimus. Moreover, we have studied the mechanisms of cell death induced by the two agents alone or in combination on EPCs and we have found that the synergistic effect of combination on EPC growth inhibition was paralleled by increased apoptosis induction and reduced autophagy. These effects occurred together with biochemical features that are typical of reduced autophagic death such as increased co-immunoprecipitation between Beclin 1 and Bcl-2. Chloroquine antagonized the inhibition of the activity of Akt→4EBP1 axis mediated by everolimus and at the same time it blocked the feed-back activation of Erk-1/2 induced by RAD in EPCs. These data suggest a new strategy in order to block angiogenesis in tumours in which this process plays a key role in both the sustainment and spreading of cancer cells. PMID:24244540

  10. Biodegradable-Polymer Biolimus-Eluting Stents versus Durable-Polymer Everolimus-Eluting Stents at One-Year Follow-Up: A Registry-Based Cohort Study

    PubMed Central

    Parsa, Ehsan; Saroukhani, Sepideh; Majlessi, Fereshteh; Poorhosseini, Hamidreza; Lofti-Tokaldany, Masoumeh; Jalali, Arash; Salarifar, Mojtaba; Nematipour, Ebrahim; Alidoosti, Mohammad; Aghajani, Hassan; Amirzadegan, Alireza

    2016-01-01

    We compared outcomes of percutaneous coronary intervention patients who received biodegradable-polymer biolimus-eluting stents with those who received durable-polymer everolimus-eluting stents. At Tehran Heart Center, we performed a retrospective analysis of the data from January 2007 through December 2011 on 3,270 consecutive patients with coronary artery disease who underwent percutaneous coronary intervention with the biodegradable-polymer biolimus-eluting stent or the durable-polymer everolimus-eluting stent. We excluded patients with histories of coronary artery bypass grafting or percutaneous coronary intervention, acute ST-segment-elevation myocardial infarction, or the implantation of 2 different stent types. Patients were monitored for 12 months. The primary endpoint was a major adverse cardiac event, defined as a composite of death, nonfatal myocardial infarction, and target-vessel and target-lesion revascularization. Durable-polymer everolimus-eluting stents were implanted in 2,648 (81%) and biodegradable-polymer biolimus-eluting stents in 622 (19%) of the study population. There was no significant difference between the 2 groups (2.7% vs 2.7%; P=0.984) in the incidence of major adverse cardiac events. The cumulative adjusted probability of major adverse cardiac events in the biodegradable-polymer biolimus-eluting stent group did not differ from that of such events in the durable-polymer everolimus-eluting stent group (hazard ratio=0.768; 95% confidence interval, 0.421–1.44; P=0.388). We conclude that in our patients the biodegradable-polymer biolimus-eluting stent was as effective and safe, during the 12-month follow-up period, as was the durable-polymer everolimus-eluting stent. PMID:27127426

  11. mTOR plays critical roles in pancreatic cancer stem cells through specific and stemness-related functions

    NASA Astrophysics Data System (ADS)

    Matsubara, Shyuichiro; Ding, Qiang; Miyazaki, Yumi; Kuwahata, Taisaku; Tsukasa, Koichiro; Takao, Sonshin

    2013-11-01

    Pancreatic cancer is characterized by near-universal mutations in KRAS. The mammalian target of rapamycin (mTOR), which functions downstream of RAS, has divergent effects on stem cells. In the present study, we investigated the significance of the mTOR pathway in maintaining the properties of pancreatic cancer stem cells. The mTOR inhibitor, rapamycin, reduced the viability of CD133+ pancreatic cancer cells and sphere formation which is an index of self-renewal of stem-like cells, indicating that the mTOR pathway functions to maintain cancer stem-like cells. Further, rapamycin had different effects on CD133+ cells compared to cyclopamine which is an inhibitor of the Hedgehog pathway. Thus, the mTOR pathway has a distinct role although both pathways maintain pancreatic cancer stem cells. Therefore, mTOR might be a promising target to eliminate pancreatic cancer stem cells.

  12. Genetic and pharmacologic evidence that mTOR targeting outweighs mTORC1 inhibition as an antimyeloma strategy.

    PubMed

    Chen, Xi; Díaz-Rodríguez, Elena; Ocio, Enrique M; Paiva, Bruno; Mortensen, Deborah S; Lopez-Girona, Antonia; Chopra, Rajesh; Miguel, Jesús San; Pandiella, Atanasio

    2014-02-01

    The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that regulates cell growth, proliferation, metabolism, and cell survival, and plays those roles by forming two functionally distinct multiprotein complexes: mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2). Deregulation of the mTOR pathway has been found in different cancers, including multiple myeloma. Agents acting on mTORC1, such as rapamycin and derivatives, are being explored as antitumoral strategies. However, whether targeting mTOR would be a more effective antimyeloma strategy than exclusively acting on the mTORC1 branch remains to be established. In this report, we explored the activation status of mTOR routes in malignant plasma cells, and analyzed the contribution of mTOR and its two signaling branches to the proliferation of myeloma cells. Gene expression profiling demonstrated deregulation of mTOR pathway-related genes in myeloma plasma cells from patients. Activation of the mTOR pathway in myelomatous plasma cells was corroborated by flow cytometric analyses. RNA interference (RNAi) experiments indicated that mTORC1 predominated over mTORC2 in the control of myeloma cell proliferation. However, mTOR knockdown had a superior antiproliferative effect than acting only on mTORC1 or mTORC2. Pharmacologic studies corroborated that the neutralization of mTOR has a stronger antimyeloma effect than the individual inhibition of mTORC1 or mTORC2. Together, our data support the clinical development of agents that widely target mTOR, instead of agents, such as rapamycin or its derivatives, that solely act on mTORC1. PMID:24431075

  13. The role of phospholipase D and phosphatidic acid in the mechanical activation of mTOR signaling in skeletal muscle.

    PubMed

    Hornberger, T A; Chu, W K; Mak, Y W; Hsiung, J W; Huang, S A; Chien, S

    2006-03-21

    Signaling by the mammalian target of rapamycin (mTOR) has been reported to be necessary for mechanical load-induced growth of skeletal muscle. The mechanisms involved in the mechanical activation of mTOR signaling are not known, but several studies indicate that a unique [phosphotidylinositol-3-kinase (PI3K)- and nutrient-independent] mechanism is involved. In this study, we have demonstrated that a regulatory pathway for mTOR signaling that involves phospholipase D (PLD) and the lipid second messenger phosphatidic acid (PA) plays a critical role in the mechanical activation of mTOR signaling. First, an elevation in PA concentration was sufficient for the activation of mTOR signaling. Second, the isozymes of PLD (PLD1 and PLD2) are localized to the z-band in skeletal muscle (a critical site of mechanical force transmission). Third, mechanical stimulation of skeletal muscle with intermittent passive stretch ex vivo induced PLD activation, PA accumulation, and mTOR signaling. Finally, pharmacological inhibition of PLD blocked the mechanically induced increase in PA and the activation of mTOR signaling. Combined, these results indicate that mechanical stimuli activate mTOR signaling through a PLD-dependent increase in PA. Furthermore, we showed that mTOR signaling was partially resistant to rapamycin in muscles subjected to mechanical stimulation. Because rapamycin and PA compete for binding to the FRB domain on mTOR, these results suggest that mechanical stimuli activate mTOR signaling through an enhanced binding of PA to the FRB domain on mTOR. PMID:16537399

  14. Twelve-month efficacy and safety of the conversion to everolimus in maintenance heart transplant recipients

    PubMed Central

    Manito, Nicolás; Delgado, Juan F; Crespo-Leiro, María G; Arizón, José María; Segovia, Javier; González-Vílchez, Francisco; Mirabet, Sònia; Lage, Ernesto; Pascual-Figal, Domingo; Díaz, Beatriz; Palomo, Jesús; Rábago, Gregorio; Sanz, Marisa; Blasco, Teresa; Roig, Eulàlia

    2015-01-01

    AIM: To determine the clinical reasons for conversion to everolimus (EVL) and long-term outcomes in heart transplant (HT) recipients. METHODS: A retrospective 12-mo study has been carried out in 14 Spanish centres to assess the efficacy and safety of conversion to EVL in maintenance HT recipients. RESULTS: Two hundred and twenty-two patients were included (mean age: 53 ± 10.5 years; mean time from HT: 8.1 ± 4.5 years). The most common reasons for conversion were nephrotoxicity (30%), chronic allograft vasculopathy (20%) and neoplasms (17%). The doses and mean levels of EVL at baseline (conversion to EVL) and after one year were 1.3 ± 0.3 and 1.2 ± 0.6 mg/d and 6.4 ± 3.4 and 5.6 ± 2.5 ng/mL, respectively. The percentage of patients receiving calcineurin inhibitors (CNIs) at baseline and on the final visit was 95% and 65%, respectively. The doses and mean levels of CNIs decreased between baseline and month 12 from 142.2 ± 51.6 to 98.0 ± 39.4 mg/d (P < 0.001) and from 126.1 ± 50.9 to 89.2 ± 47.7 ng/mL (P < 0.001), respectively, for cyclosporine, and from 2.9 ± 1.8 to 2.6 ± 1.9 mg/d and from 8.3 ± 4.0 to 6.5 ± 2.7 ng/mL (P = 0.011) for tacrolimus. In the subgroup of patients converted because of nephrotoxicity, creatinine clearance increased from 34.9 ± 10.1 to 40.4 ± 14.4 mL/min (P < 0.001). There were 37 episodes of acute rejection in 24 patients (11%). The most frequent adverse events were oedemas (12%), infections (9%) and gastrointestinal problems (6%). EVL was suspended in 44 patients (20%). Since the database was closed at the end of the study, no further follow-up data is available. CONCLUSION: Conversion to EVL in maintenance HT recipients allowed minimisation or suspension of the CNIs, with improved kidney function in the patients with nephrotoxicity, after 12 mo. PMID:26722659

  15. Exercise improves skeletal muscle insulin resistance without reduced basal mTOR/S6K1 signaling in rats fed a high-fat diet.

    PubMed

    Liao, Bagen; Xu, Yong

    2011-11-01

    Exercise improves high-fat diet (HFD)-induced skeletal muscle insulin resistance, but the mechanism is unresolved. This study aims to explore whether the improvement in response to exercise is associated with mTOR/S6K1 signaling and whether the signaling changes are muscle-specific. Male SD rats (150-180 g) were used for this study. After the experimental period, 6 weeks of exercise improved HFD-impaired intraperitoneal glucose tolerance and insulin-stimulated 2-deoxyglucose uptake in soleus (SOL) and extensor digitorum longus (EDL) muscles. Furthermore, 6 weeks of the HFD resulted in a reduced type I fiber ratio of SOL, an increased type I ratio of EDL, and a reduced fiber size of EDL, whereas exercise increased type I fiber ratio of SOL as well as type I fiber cross-sectional areas of EDL. However, the HFD had a main effect on basal cytosolic phosphorylation of S6K1 on Thr(389) content in SOL, which was also influenced by a significant interaction between the diet and exercise in EDL. Exercise had no direct effect on the basal phosphorylation of Akt on Ser(473), mTOR on Ser(2448), S6K1 on Thr(389) content in SOL. On the contrary, exercise prevented HFD-induced decrease in basal phosphorylation of S6K1 on Thr(389) content in EDL. These results indicate that 6 weeks of HFD and exercise lead to alterations in fiber type shift, fiber size, and basal phosphorylation of S6K1 on Thr(389) content in a muscle-specific pattern. Exercise prevents HFD-induced skeletal muscle insulin resistance, which is not associated with a reduced basal phosphorylation of mTOR/S6K1 alteration in the muscles. PMID:21404070

  16. mTOR as a Molecular Target in HPV-Associated Oral and Cervical Squamous Carcinomas

    PubMed Central

    Molinolo, Alfredo A.; Marsh, Christina; Dinali, Mohamed El; Gangane, Nitin; Jennison, Kaitlin; Hewitt, Stephen; Patel, Vyomesh; Seiwert, Tanguy Y.; Gutkind, J. Silvio

    2012-01-01

    Purpose The incidence of head and neck squamous cell carcinomas (HNSCC) associated with papillomavirus (HPV) infection has increased over the past decades in the US. We aimed at examining the global impact of HPV-associated HNSCC, and whether the established key role of mTOR activation in HNSCC is also observed in HPV+ HNSCC lesions, thereby providing novel treatment options for HPV-associated HNSCC patients. Experimental Design An international HNSCC tissue microarray (TMA) was used to analyze the expression of p16INK4A, a surrogate for HPV infection, and Akt-mTOR pathway activation. Results were confirmed in a large collection of HPV− and HPV+ HNSCC cases and in a cervical cancer (CCSCC) TMA. Observations were validated in HNSCC and CCSCC-derived cell lines, which were xenografted into immunodeficient mice for tumorigenesis assays. Results Approximately 20% of all HNSCC lesions could be classified as HPV+, irrespective of their country of origin. mTOR pathway activation was observed in most HPV+ HNSCC and CCSCC lesions and cell lines. The pre-clinical efficacy of mTOR inhibition by rapamycin and RAD001 was explored in HPV+ HNSCC and CCSCC tumor xenografts. Both mTOR inhibitors effectively decreased mTOR activity in vivo, and caused a remarkable decrease in tumor burden. These results emphasize the emerging global impact of HPV-related HNSCCs, and indicate that the activation of the mTOR pathway is a widespread event in both HPV− and HPV-associated HNSCC and CCSCC lesions. Conclusions The emerging results may provide a rationale for the clinical evaluation of mTOR inhibitors as a molecular targeted approach for the treatment of HPV-associated malignancies. PMID:22409888

  17. Cutting through the Complexities of mTOR for the Treatment of Stroke

    PubMed Central

    Maiese, Kenneth

    2014-01-01

    On a global basis, at least 15 million individuals suffer some form of a stroke every year. Of these individuals, approximately 800,000 of these cerebrovascular events occur in the United States (US) alone. The incidence of stroke in the US has declined from the third leading cause of death to the fourth, a result that can be attributed to multiple factors that include improved vascular disease management, reduced tobacco use, and more rapid time to treatment in patients that are clinically appropriate to receive recombinant tissue plasminogen activator. However, treatment strategies for the majority of stroke patients are extremely limited and represent a critical void for care. A number of new therapeutic considerations for stroke are under consideration, but it is the mammalian target of rapamycin (mTOR) that is receiving intense focus as a potential new target for cerebrovascular disease. As part of the phosphoinositide 3-kinase (PI 3-K) and protein kinase B (Akt) cascade, mTOR is an essential component of mTOR Complex 1 (mTORC1) and mTOR Complex 2 (mTORC2) to govern cell death involving apoptosis, autophagy, and necroptosis, cellular metabolism, and gene transcription. Vital for the consideration of new therapeutic strategies for stroke is the ability to understand how the intricate and complex pathways of mTOR signaling sometimes lead to disparate clinical outcomes. PMID:24712647

  18. mTOR inhibition sensitizes human hepatocellular carcinoma cells to resminostat.

    PubMed

    Peng, Xingang; Zhang, Donghui; Li, Zhengling; Fu, Meili; Liu, Haiyan

    2016-09-01

    Histone deacetylases (HDACs) hyper-activity in hepatocellular carcinoma (HCC) is often associated with patients' poor prognosis. Our previous study has shown that resminostat, a novel HDAC inhibitor (HDACi), activated mitochondrial permeability transition pore (mPTP)-dependent apoptosis pathway in HCC cells. Here we explored the potential resminostat resistance factor by focusing on mammalian target of rapamycin (mTOR). We showed that AZD-2014, a novel mTOR kinase inhibitor, potentiated resminostat-induced cytotoxicity and proliferation inhibition in HCC cells. Molecularly, AZD-2014 enhanced resminostat-induced mPTP apoptosis pathway activation in HCC cells. Inhibition of this apoptosis pathway, by the caspase-9 specific inhibitor Ac-LEHD-CHO, the mPTP blockers (sanglifehrin A/cyclosporine A), or by shRNA-mediated knockdown of mPTP component cyclophilin-D (Cyp-D), significantly attenuated resminostat plus AZD-2014-induced cytotoxicity and apoptosis in HCC cells. Significantly, mTOR shRNA knockdown or kinase-dead mutation (Asp-2338-Ala) also sensitized HCC cells to resminostat, causing profound cytotoxicity and apoptosis induction. Together, these results suggest that mTOR could be a primary resistance factor of resminostat. Targeted inhibition of mTOR may thus significantly sensitize HCC cells to resminostat. PMID:27311860

  19. Cardamonin Inhibits Metastasis of Lewis Lung Carcinoma Cells by Decreasing mTOR Activity

    PubMed Central

    Niu, Pei-Guang; Zhang, Yu-Xuan; Shi, Dao-Hua; Liu, Ying; Chen, Yao-Yao; Deng, Jie

    2015-01-01

    The mammalian target of rapamycin (mTOR) regulates the motility and invasion of cancer cells. Cardamonin is a chalcone that exhibits anti-tumor activity. The previous study had proved that the anti-tumor effect of cardamonin was associated with mTOR inhibition. In the present study, the anti-metastatic effect of cardamonin and its underlying molecule mechanisms were investigated on the highly metastatic Lewis lung carcinoma (LLC) cells. The proliferation, invasion and migration of LLC cells were measured by MTT, transwell and wound healing assays, respectively. The expression and activation of mTOR- and adhesion-related proteins were assessed by Western blotting. The in vivo effect of cardamonin on the metastasis of the LLC cells was investigated by a mouse model. Treated with cardamonin, the proliferation, invasion and migration of LLC cells were significantly inhibited. The expression of Snail was decreased by cardamonin, while that of E-cadherin was increased. In addition, cardamonin inhibited the activation of mTOR and its downstream target ribosomal S6 kinase 1 (S6K1). Furthermore, the tumor growth and its lung metastasis were inhibited by cardamonin in C57BL/6 mice. It indicated that cardamonin inhibited the invasion and metastasis of LLC cells through inhibiting mTOR. The metastasis inhibitory effect of cardamonin was correlated with down-regulation of Snail and up-regulation of E-cadherin. PMID:25996501

  20. mTOR: Driving apoptosis and autophagy for neurocardiac complications of diabetes mellitus

    PubMed Central

    Maiese, Kenneth

    2015-01-01

    The World Health Organization estimates that diabetes mellitus (DM) will become the seventh leading cause of death during the next two decades. DM affects approximately 350 million individuals worldwide and additional millions that remain undiagnosed are estimated to suffer from the complications of DM. Although the complications of DM can be seen throughout the body, the nervous, cardiac, and vascular systems can be significantly affected and lead to disorders that include cognitive loss, stroke, atherosclerosis, cardiac failure, and endothelial stem cell impairment. At the cellular level, oxidative stress is a significant determinant of cell fate during DM and leads to endoplasmic reticulum stress, mitochondrial dysfunction, apoptosis, and autophagy. Multiple strategies are being developed to combat the complications of DM, but it is the mechanistic target of rapamycin (mTOR) that is gaining interest in drug development circles especially for protective therapies that involve cytokines and growth factors such as erythropoietin. The pathways of mTOR linked to mTOR complex 1, mTOR complex 2, AMP activated protein kinase, and the hamartin (tuberous sclerosis 1)/tuberin (tuberous sclerosis 2) complex can ultimately influence neuronal, cardiac, and vascular cell survival during oxidant stress in DM through a fine interplay between apoptosis and autophagy. Further understanding of these mTOR regulated pathways should foster novel strategies for the complications of DM that impact millions of individuals with death and disability. PMID:25789103

  1. Immune responses of macrophages and dendritic cells regulated by mTOR signalling.

    PubMed

    Katholnig, Karl; Linke, Monika; Pham, Ha; Hengstschläger, Markus; Weichhart, Thomas

    2013-08-01

    The innate myeloid immune system is a complex network of cells that protect against disease by identifying and killing pathogens and tumour cells, but it is also implicated in homoeostatic mechanisms such as tissue remodelling and wound healing. Myeloid phagocytes such as monocytes, macrophages or dendritic cells are at the basis of controlling these immune responses in all tissues of the body. In the present review, we summarize recent studies demonstrating that mTOR [mammalian (or mechanistic) target of rapamycin] regulates innate immune reactions in macrophages and dendritic cells. The mTOR pathway serves as a decision maker to control the cellular response to pathogens and tumours by regulating the expression of inflammatory mediators such as cytokines, chemokines or interferons. In addition to various in vivo mouse models, kidney transplant patients under mTOR inhibitor therapy allowed the elucidation of important innate immune functions regulated by mTOR in humans. The role of the mTOR pathway in macrophages and dendritic cells enhances our understanding of the immune system and suggests new therapeutic avenues for the regulation of pro- versus anti-inflammatory mediators with potential relevance to cancer therapy, the design of novel adjuvants and the control of distinct infectious and autoimmune diseases. PMID:23863158

  2. Temporal mTOR inhibition protects Fbxw7-deficient mice from radiation-induced tumor development

    PubMed Central

    Liu, Yueyong; Huang, Yurong; Wang, Zeran; Huang, Yong; Li, Xiaohua; Louie, Alexander; Wei, Guangwei; Mao, Jian-Hua

    2013-01-01

    FBXW7 acts as a tumor suppressor in numerous types of human cancers through ubiquitination of different oncoproteins including mTOR. However, how the mutation/loss of Fbxw7 results in tumor development remains largely unknown. Here we report that downregulation of mTOR by radiation is Fbxw7-dependent, and short-term mTOR inhibition by rapamycin after exposure to radiation significantly postpones tumor development in Fbxw7/p53 double heterozygous (Fbxw7+/−p53+/−) mice but not in p53 single heterozygous (p53+/−) mice. Tumor latency of rapamycin treated Fbxw7+/−p53+/− mice is remarkably similar to those of p53+/− mice while placebo treated Fbxw7+/−p53+/− mice develop tumor significantly earlier than placebo treated p53+/− mice. Furthermore, we surprisingly find that, although temporal treatment of rapamycin is given at a young age, the inhibition of mTOR activity sustainably remains in tumors. These results indicate that inhibition of mTOR signaling pathway suppresses the contribution of Fbxw7 loss toward tumor development. PMID:23454868

  3. ESAT6 inhibits autophagy flux and promotes BCG proliferation through MTOR.

    PubMed

    Dong, Hu; Jing, Wu; Runpeng, Zhao; Xuewei, Xu; Min, Mu; Ru, Cai; Yingru, Xing; Shengfa, Ni; Rongbo, Zhang

    2016-08-19

    In recent years, increasing studies have found that pathogenic Mycobacterium tuberculosis (Mtb) inhibits autophagy, which mediates the anti-mycobacterial response, but the mechanism is not clear. We previously reported that secretory acid phosphatase (SapM) of Mtb can negatively regulate autophagy flux. Recently, another virulence factor of Mtb, early secretory antigenic target 6 (ESAT6), has been found to be involved in inhibiting autophagy, but the mechanism remains unclear. In this study, we show that ESAT6 hampers autophagy flux to boost bacillus Calmette-Guerin (BCG) proliferation and reveals a mechanism by which ESAT6 blocks autophagosome-lysosome fusion in a mammalian target of rapamycin (MTOR)-dependent manner. In both Raw264.7 cells and primary macrophages derived from the murine abdominal cavity (ACM), ESAT6 repressed autophagy flux by interfering with the autophagosome-lysosome fusion, which resulted in an increased load of BCG. Impaired degradation of LC3Ⅱ and SQSTM1 by ESAT6 was related to the upregulated activity of MTOR. Contrarily, inhibiting MTOR with Torin1 removed the ESAT6-induced autophagy block and lysosome dysfunction. Furthermore, in both Raw264.7 and ACM cells, MTOR inhibition significantly suppressed the survival of BCG. In conclusion, our study highlights how ESAT6 blocks autophagy and promotes BCG survival in a way that activates MTOR. PMID:27317487

  4. A phase 2 trial of everolimus and pasireotide long-acting release in patients with metastatic uveal melanoma.

    PubMed

    Shoushtari, Alexander N; Ong, Leonard T; Schoder, Heiko; Singh-Kandah, Shahnaz; Abbate, Kelly T; Postow, Michael A; Callahan, Margaret K; Wolchok, Jedd; Chapman, Paul B; Panageas, Katherine S; Schwartz, Gary K; Carvajal, Richard D

    2016-06-01

    The aim of this study was to test the hypothesis that inhibiting mammalian target of rapamycin and insulin-like growth factor-1 receptor would be efficacious in metastatic uveal melanoma. This was a phase 2 trial of everolimus 10 mg daily plus pasireotide long-acting release 60 mg every 28 days enrolling patients with progressive, metastatic uveal melanoma to treatment until progression by Response Evaluation Criteria In Solid Tumors 1.1 (RECIST 1.1) or unacceptable toxicity. The primary endpoint was clinical benefit rate, defined as any objective response or RECIST 1.1 stable disease at 16 weeks. A subset of patients underwent baseline indium-111-octreotide scans. A total of 14 patients were enrolled, of which 13 were evaluable for the primary endpoint, before the study was terminated due to poor accrual. Three of 13 (26%) patients obtained clinical benefit. Seven of 13 (54%) had stable disease lasting for a median of 8 weeks (range: 8-16 weeks). Grade 3 adverse events deemed at least possibly related to study drugs were hyperglycemia (n=7), oral mucositis (n=2), diarrhea (n=1), hypophosphatemia (n=1), and anemia (n=1). Seven of 14 (50%) patients required at least one dose reduction due to toxicity. Seven of eight (88%) patients with baseline indium-111-octreotide scans had at least one avid lesion, with significant intrapatient heterogeneity. There was a trend toward an association between octreotide avidity and cytostatic response to therapy (P=0.078). The combination of everolimus and pasireotide has limited clinical benefit in this small metastatic uveal melanoma cohort. Dose reductions for side effects were common. Further investigation into the relationship between somatostatin receptor expression and cytostatic activity of somatostatin analogues is warranted. PMID:26795274

  5. mTOR Links Environmental Signals to T Cell Fate Decisions

    PubMed Central

    Chapman, Nicole M.; Chi, Hongbo

    2015-01-01

    T cell fate decisions play an integral role in maintaining the health of organisms under homeostatic and inflammatory conditions. The localized microenvironment in which developing and mature T cells reside provides signals that serve essential functions in shaping these fate decisions. These signals are derived from the immune compartment, including antigens, co-stimulation, and cytokines, and other factors, including growth factors and nutrients. The mechanistic target of rapamycin (mTOR), a vital sensor of signals within the immune microenvironment, is a central regulator of T cell biology. In this review, we discuss how various environmental cues tune mTOR activity in T cells, and summarize how mTOR integrates these signals to influence multiple aspects of T cell biology. PMID:25653651

  6. The crosstalk of mTOR/S6K1 and Hedgehog pathways.

    PubMed

    Wang, Yan; Ding, Qingqing; Yen, Chia-Jui; Xia, Weiya; Izzo, Julie G; Lang, Jing-Yu; Li, Chia-Wei; Hsu, Jennifer L; Miller, Stephanie A; Wang, Xuemei; Lee, Dung-Fang; Hsu, Jung-Mao; Huo, Longfei; Labaff, Adam M; Liu, Dongping; Huang, Tzu-Hsuan; Lai, Chien-Chen; Tsai, Fuu-Jen; Chang, Wei-Chao; Chen, Chung-Hsuan; Wu, Tsung-Teh; Buttar, Navtej S; Wang, Kenneth K; Wu, Yun; Wang, Huamin; Ajani, Jaffer; Hung, Mien-Chie

    2012-03-20

    Esophageal adenocarcinoma (EAC) is the most prevalent esophageal cancer type in the United States. The TNF-α/mTOR pathway is known to mediate the development of EAC. Additionally, aberrant activation of Gli1, downstream effector of the Hedgehog (HH) pathway, has been observed in EAC. In this study, we found that an activated mTOR/S6K1 pathway promotes Gli1 transcriptional activity and oncogenic function through S6K1-mediated Gli1 phosphorylation at Ser84, which releases Gli1 from its endogenous inhibitor, SuFu. Moreover, elimination of S6K1 activation by an mTOR pathway inhibitor enhances the killing effects of the HH pathway inhibitor. Together, our results established a crosstalk between the mTOR/S6K1 and HH pathways, which provides a mechanism for SMO-independent Gli1 activation and also a rationale for combination therapy for EAC. PMID:22439934

  7. The Crosstalk of mTOR/S6K1 and Hedgehog pathways

    PubMed Central

    Wang, Yan; Ding, Qingqing; Yen, Chia-Jui; Xia, Weiya; Izzo, Julie G.; Lang, Jing-Yu; Li, Chia-Wei; Hsu, Jennifer L.; Miller, Stephanie A.; Wang, Xuemei; Lee, Dung-Fang; Hsu, Jung-Mao; Huo, Longfei; LaBaff, Adam M.; Liu, Dong-Ping; Huang, Tzu-Hsuan; Lai, Chien-Chen; Tsai, Fuu-Jen; Chang, Wei-Chao; Chen, Chung-Hsuan; Wu, Tsung-Teh; Buttar, Navtej S.; Wang, Kenneth K.; Wu, Yun; Wang, Huamin; Ajani, Jaffer; Hung, Mien-Chie

    2012-01-01

    Summary Esophageal adenocarcinoma (EAC) is the most prevalent esophageal cancer type in the United States. TNFα/mTOR pathway is known to mediate the development of EAC. Additionally, aberrant activation of Gli1, downstream effector of hedgehog pathway, has been observed in EAC. In this study, we found that activated mTOR/S6K1 pathway promotes Gli1 transcriptional activity and oncogenic function through S6K1-mediated Gli1 phosphorylation at Ser84, which releases Gli1 from its endogenous inhibitor, SuFu. Moreover, elimination of S6K1 activation by mTOR pathway inhibitor enhances the killing effects of the hedgehog pathway inhibitor. Together, our results established a crosstalk between mTOR/S6K1 and the hedgehog pathways, which provides not only a mechanism for SMO-independent Gli1 activation but also a rationale for combination therapy for EAC. PMID:22439934

  8. Che-1-induced inhibition of mTOR pathway enables stress-induced autophagy

    PubMed Central

    Desantis, Agata; Bruno, Tiziana; Catena, Valeria; De Nicola, Francesca; Goeman, Frauke; Iezzi, Simona; Sorino, Cristina; Ponzoni, Maurilio; Bossi, Gianluca; Federico, Vincenzo; La Rosa, Francesca; Ricciardi, Maria Rosaria; Lesma, Elena; De Meo, Paolo D'Onorio; Castrignanò, Tiziana; Petrucci, Maria Teresa; Pisani, Francesco; Chesi, Marta; Bergsagel, P Leif; Floridi, Aristide; Tonon, Giovanni; Passananti, Claudio; Blandino, Giovanni; Fanciulli, Maurizio

    2015-01-01

    Mammalian target of rapamycin (mTOR) is a key protein kinase that regulates cell growth, metabolism, and autophagy to maintain cellular homeostasis. Its activity is inhibited by adverse conditions, including nutrient limitation, hypoxia, and DNA damage. In this study, we demonstrate that Che-1, a RNA polymerase II-binding protein activated by the DNA damage response, inhibits mTOR activity in response to stress conditions. We found that, under stress, Che-1 induces the expression of two important mTOR inhibitors, Redd1 and Deptor, and that this activity is required for sustaining stress-induced autophagy. Strikingly, Che-1 expression correlates with the progression of multiple myeloma and is required for cell growth and survival, a malignancy characterized by high autophagy response. PMID:25770584

  9. Inhibition of the mechanistic target of rapamycin (mTOR) - Rapamycin and beyond

    PubMed Central

    Lamming, Dudley W.

    2016-01-01

    Rapamycin is an FDA-approved immunosuppressant and anti-cancer agent discovered in the soil of Easter Island in the early 1970s. Rapamycin is a potent and selective inhibitor of the mTOR (mechanistic Target Of Rapamycin) protein kinase, which acts as a central integrator of nutrient signaling pathways. During the last decade, genetic and pharmaceutical inhibition of mTOR pathway signaling has been found to promote longevity in yeast, worms, flies and mice. In this chapter, we will discuss the molecular biology underlying the effects of rapamycin and its physiological effects; evidence for rapamycin as an anti-aging compound; mechanisms by which rapamycin may extend lifespan; and the potential limitations of rapamycin as an anti-aging molecule. Finally, we will discuss possible strategies that may allow us to inhibit mTOR signaling safely while minimizing side effects, and reap the health, social and economic benefits from slowing the aging process. PMID:27048303

  10. LAMTOR2 regulates dendritic cell homeostasis through FLT3-dependent mTOR signalling

    PubMed Central

    Scheffler, Julia M.; Sparber, Florian; Tripp, Christoph H.; Herrmann, Caroline; Humenberger, Alexandra; Blitz, Johanna; Romani, Nikolaus; Stoitzner, Patrizia; Huber, Lukas A.

    2014-01-01

    The receptor tyrosine kinase Flt3 and its ligand are crucial for dendritic cell (DC) homeostasis by activating downstream effectors including mammalian target of Rapamycin (mTOR) signalling. LAMTOR2 is a member of the Ragulator/LAMTOR complex known to regulate mTOR and extracellular signal-regulated kinase activation on the late endosome as well as endosomal biogenesis. Here we show in mice that conditional ablation of LAMTOR2 in DCs results in a severe disturbance of the DC compartment caused by accumulation of Flt3 on the cell surface. This results in an increased downstream activation of the AKT/mTOR signalling pathway and subsequently to a massive expansion of conventional DCs and plasmacytoid DCs in ageing mice. Finally, we can revert the symptoms in vivo by inhibiting the activation of Flt3 and its downstream target mTOR. PMID:25336251

  11. mTOR remains unchanged in diet-resistant (DR) rats despite impaired LKB1/AMPK cascade in adipose tissue.

    PubMed

    Han, Jie; Liang, Huimin; Tian, Derun; Du, Jianying; Wang, Qiming; Xi, Pengjiao; Wang, Haomin; Li, Yongmei

    2016-08-01

    Liver kinase B1 (LKB1) plays an important role in adipogenesis, but the underlying molecular mechanism is poorly understood. Here, we explored the functional relationship between LKB1 and the mammalian target of rapamycin (mTOR) in regulating adipogenesis in rats and preadipocytes. We found that LKB1 and the adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) cascade are impaired in the white adipose tissue (WAT) of diet-induced obesity (DIO) and diet-resistant (DR) rats when compared with chow-fed (CF) rats. While DIO activated the mTOR pathway in WAT and led to a more fat mass gain, DR maintained the normal activity of the mTOR pathway and normal weight and percentage of fat mass. We further constructed overexpressed LKB1 (OE) and silenced LKB1 (Si) 3T3-L1 preadipocytes monoclonal cell lines. In the OE cell line, the mTOR pathway was inactivated, and intracellular lipid content was reduced during differentiation. This effect could be reversed by AMPK inhibition. Conversely, in the Si cell line, the mTOR pathway was activated and intracellular lipid content increased. This effect could be reversed by rapamycin, an inhibitor of mTOR. Our results suggest that mTOR mediates the effect of LKB1 on adipogenesis, and normal activity of mTOR in DR rats interferes with the effect of LKB1 in WAT. PMID:27235551

  12. Age related increase in mTOR activity contributes to the pathological changes in ovarian surface epithelium

    PubMed Central

    Bajwa, Preety; Nagendra, Prathima B.; Nielsen, Sarah; Sahoo, Subhransu S.; Bielanowicz, Amanda; Lombard, Janine M.; Wilkinson, Erby J.; Miller, Richard A.; Tanwar, Pradeep S.

    2016-01-01

    Ovarian cancer is a disease of older women. However, the molecular mechanisms of ovarian aging and their contribution to the pathogenesis of ovarian cancer are currently unclear. mTOR signalling is a major regulator of aging as suppression of this pathway extends lifespan in model organisms. Overactive mTOR signalling is present in up to 80% of ovarian cancer samples and is associated with poor prognosis. This study examined the role of mTOR signalling in age-associated changes in ovarian surface epithelium (OSE). Histological examination of ovaries from both aged mice and women revealed OSE cell hyperplasia, papillary growth and inclusion cysts. These pathological lesions expressed bonafide markers of ovarian cancer precursor lesions, Pax8 and Stathmin 1, and were presented with elevated mTOR signalling. To understand whether overactive mTOR signalling is responsible for the development of these pathological changes, we analysed ovaries of the Pten trangenic mice and found significant reduction in OSE lesions compared to controls. Furthermore, pharmacological suppression of mTOR signalling significantly decreased OSE hyperplasia in aged mice. Treatment with mTOR inhibitors reduced human ovarian cancer cell viability, proliferation and colony forming ability. Collectively, we have established the role of mTOR signalling in age-related OSE pathologies and initiation of ovarian cancer. PMID:27036037

  13. Comparative idiosyncrasies in life extension by reduced mTOR signalling and its distinctiveness from dietary restriction.

    PubMed

    Garratt, Michael; Nakagawa, Shinichi; Simons, Mirre J P

    2016-08-01

    Reduced mechanistic target of rapamycin (mTOR) signalling extends lifespan in yeast, nematodes, fruit flies and mice, highlighting a physiological pathway that could modulate aging in evolutionarily divergent organisms. This signalling system is also hypothesized to play a central role in lifespan extension via dietary restriction. By collating data from 48 available published studies examining lifespan with reduced mTOR signalling, we show that reduced mTOR signalling provides similar increases in median lifespan across species, with genetic mTOR manipulations consistently providing greater life extension than pharmacological treatment with rapamycin. In contrast to the consistency in changes in median lifespan, however, the demographic causes for life extension are highly species specific. Reduced mTOR signalling extends lifespan in nematodes by strongly reducing the degree to which mortality rates increase with age (aging rate). By contrast, life extension in mice and yeast occurs largely by pushing back the onset of aging, but not altering the shape of the mortality curve once aging starts. Importantly, in mice, the altered pattern of mortality induced by reduced mTOR signalling is different to that induced by dietary restriction, which reduces the rate of aging. Effects of mTOR signalling were also sex dependent, but only within mice, and not within flies, thus again species specific. An alleviation of age-associated mortality is not a shared feature of reduced mTOR signalling across model organisms and does not replicate the established age-related survival benefits of dietary restriction. PMID:27139919

  14. A carbazole alkaloid deactivates mTOR through the suppression of rictor and that induces apoptosis in lung cancer cells.

    PubMed

    Chatterjee, Priyajit; Seal, Soma; Mukherjee, Sandip; Kundu, Rakesh; Bhuyan, Mantu; Barua, Nabin C; Baruah, Pranab K; Babu, Santi Prasad Sinha; Bhattacharya, Samir

    2015-07-01

    Non-small cell lung cancer (NSCLC) is known to be a difficult cancer to treat because of its poor prognosis, limited option for surgery, and resistance to chemo or radiotherapy. In this study, we have demonstrated that suppression of rictor expression in A549 and H1299 NSCLC cells by mahanine, a carbazole alkaloid, disrupted constitutive activation of mTOR and Akt. Mahanine suppression of rictor gene expression and consequent attenuation of its protein expression affected the inhibition of mTOR (Ser-2481) and Akt (Ser-473) phosphorylation. Since mahanine treatment revealed this new insight of rictor-mTOR relationship, we examined an association between mTOR activation with rictor expression. Interestingly, in rictor knockdown (KD) NSCLC cells, mTOR activation was significantly impaired. Transfection of rictor over-expression vector into the NSCLC cells reversed this situation. In fact, both rictor KD and mahanine treated cells showed considerably depleted phospho-mTOR level. These results indicate that rictor is required to maintain constitutive activation of mTOR in lung cancer cells. When mTOR kinase activity in rictor KD cells was examined with Akt as substrate, a significant reduction of Akt phosphorylation indicated impairment of mTOR kinase potentiality. Disruption of mTOR and Akt activation caused drastic mortality of NSCLC cancer cells through apoptosis. Hence, our study reveals a new dimension in mTOR-rictor relationship, where rictor stands to be a suitable therapeutic target for lung cancer. PMID:25893736

  15. Rapamycin-resistant and torin-sensitive mTOR signaling promotes the survival and proliferation of leukemic cells

    PubMed Central

    Park, Seohyun; Sim, Hyunsub; Lee, Keunwook

    2016-01-01

    The serine/threonine kinase mTOR is essential for the phosphoinositide 3-kinases (PI3K) signaling pathway, and regulates the development and function of immune cells. Aberrant activation of mTOR signaling pathway is associated with many cancers including leukemia. Here, we report the contributions of mTOR signaling to growth of human leukemic cell lines and mouse T-cell acute leukemia (T-ALL) cells. Torin, an ATP-competitive mTOR inhibitor, was found to have both cytotoxic and cytostatic effects on U-937, THP-1, and RPMI-8226 cells, but not on Jurkat or K-562 cells. All cells were relatively resistant to rapamycin even with suppressed activity of mTOR complex 1. Growth of T-ALL cells induced by Notch1 was profoundly affected by torin partially due to increased expression of Bcl2l11 and Bbc3. Of note, activation of Akt or knockdown of FoxO1 mitigated the effect of mTOR inhibition on T-ALL cells. Our data provide insight on the effect of mTOR inhibitors on the survival and proliferation of leukemic cells, thus further improving our understanding on cell-context-dependent impacts of mTOR signaling. [BMB Reports 2016; 49(1): 63-68] PMID:26497580

  16. Hypothalamic roles of mTOR complex I: Integration of nutrient and hormone signals to regulate energy homeostasis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mammalian or mechanistic target of rapamycin (mTOR) senses nutrient, energy, and hormone signals to regulate metabolism and energy homeostasis. mTOR activity in the hypothalamus, which is associated with changes in energy status, plays a critical role in the regulation of food intake and body weight...

  17. Characterization of Torin2, an ATP-competitive inhibitor of mTOR, ATM and ATR

    PubMed Central

    Liu, Qingsong; Xu, Chunxiao; Kirubakaran, Sivapriya; Zhang, Xin; Hur, Wooyoung; Liu, Yan; Kwiatkowski, Nicholas P.; Wang, Jinhua; Westover, Kenneth D.; Gao, Peng; Ercan, Dalia; Niepel, Mario; Thoreen, Carson C.; Kang, Seong A.; Patricelli, Matthew P.; Wang, Yuchuan; Tupper, Tanya; Altabef, Abigail; Kawamura, Hidemasa; Held, Kathryn D.; Chou, Danny M.; Elledge, Stephen J.; Janne, Pasi A.; Wong, Kwok-Kin; Sabatini, David M.; Gray, Nathanael S.

    2013-01-01

    mTOR is a highly conserved serine/threonine protein kinase that serves as a central regulator of cell growth, survival and autophagy. Deregulation of the PI3K/Akt/mTOR signaling pathway occurs commonly in cancer and numerous inhibitors targeting the ATP-binding site of these kinases are currently undergoing clinical evaluation. Here we report the characterization of Torin2, a second generation ATP-competitive inhibitor that is potent and selective for mTOR with a superior pharmacokinetic profile to previous inhibitors. Torin2 inhibited mTORC1-dependent T389 phosphorylation on S6K (RPS6KB1) with an EC50 of 250 pM with approximately 800-fold selectivity for cellular mTOR versus PI3K. Torin2 also exhibited potent biochemical and cellular activity against PIKK family kinases including ATM (EC50 28 nM), ATR (EC50 35 nM) and DNA-PK (EC50 118 nM) (PRKDC), the inhibition of which sensitized cells to Irradiation. Similar to the earlier generation compound Torin1 and in contrast to other reported mTOR inhibitors, Torin2 inhibited mTOR kinase and mTORC1 signaling activities in a sustained manner suggestive of a slow dissociation from the kinase. Cancer cell treatment with Torin2 for 24 hours resulted in a prolonged block in negative feedback and consequent T308 phosphorylation on Akt. These effects were associated with strong growth inhibition in vitro. Single agent treatment with Torin2 in vivo did not yield significant efficacy against KRAS-driven lung tumors, but the combination of Torin2 with MEK inhibitor AZD6244 yielded a significant growth inhibition. Taken together, our findings establish Torin2 as a strong candidate for clinical evaluation in a broad number of oncological settings where mTOR signaling has a pathogenic role. PMID:23436801

  18. mTOR inhibition as an adjuvant therapy in a metastatic model of HPV+ HNSCC.

    PubMed

    Coppock, Joseph D; Vermeer, Paola D; Vermeer, Daniel W; Lee, Kimberly M; Miskimins, W Keith; Spanos, William C; Lee, John H

    2016-04-26

    Effective treatments for recurrent/metastatic human papillomavirus-positive (HPV+) head and neck squamous cell cancer (HNSCC) are limited. To aid treatment development, we characterized a novel murine model of recurrent/metastatic HPV+ HNSCC. Further analysis of the parental tumor cell line and its four recurrent/metastatic derivatives led to preclinical testing of an effective treatment option for this otherwise fatal disease. Reverse phase protein arrays identified key signaling cascades in the parental and recurrent/metastatic cell lines. While protein expression profiles differed among the recurrent/metastatic cell lines, activated proteins associated with the mTOR signaling cascade were a commonality. Based on these data, mTOR inhibition was evaluated as an adjuvant treatment for recurrent/metastatic disease. mTOR activity and treatment response were assessed in vitro by western blot, Seahorse, proliferation, clonogenic, and migration assays. Standard-of-care cisplatin/radiation therapy (CRT) versus CRT/rapamycin were compared in vivo. Low-dose rapamycin inhibited mTOR signaling, decreasing proliferation (43%) and migration (62%) while it enhanced CRT-induced cytotoxicity (3.3 fold) in clonogenic assays. Furthermore, rapamycin re-sensitized CRT-resistant, metastatic tumors to treatment in vivo, improving long-term cures (0-30% improved to 78-100%, depending on the recurrent/metastatic cell line) and limiting lymph node metastasis (32%) and lung metastatic burden (30 fold). Studies using immune compromised mice suggested rapamycin's effect on metastasis is independent of the adaptive immune response. These data suggest a role of mTOR activation in HPV+ HNSCC recurrent/metastatic disease and that adjuvant mTOR inhibition may enhance treatment of resistant, metastatic cell populations at the primary site and limit distant metastasis. PMID:27015118

  19. Combined treatment with everolimus and fulvestrant reversed anti-HER2 resistance in a patient with refractory advanced breast cancer: a case report

    PubMed Central

    Sun, Bing; Ding, Lijuan; Wu, Shikai; Meng, Xiangying; Song, Santai

    2016-01-01

    Background Everolimus, an inhibitor of the mammalian target of rapamycin, shows promising antitumor activity when combined with trastuzumab and chemotherapy for human epidermal growth factor receptor-2 (HER2)-positive breast cancer or when combined with endocrine agents for hormone receptor (HR)-positive tumors. However, data are limited regarding the effect of everolimus in combination with endocrine drugs in HER2-positive advanced breast cancer regardless of the HR status. Case presentation A 44-year-old female was diagnosed with recurrent HER2-positive breast cancer. The primary tumor was HR positive; however, the metastatic tumor was HR negative. The patient was resistant to classical chemotherapeutic agents and anti-HER2 treatment. Thus, the combination of everolimus and fulvestrant, a selective estrogen receptor downregulator, was chosen to reverse the resistance to anti-HER2 therapy. Indeed, the patient experienced long-term disease stabilization. Adverse events associated with the treatment were manageable by dose adjustments. We performed genetic testing of the metastatic tumor, which harbored a PIK3CA gene mutation but was positive for phosphatase and tensin homologue expression, which might result in resistance to the mammalian target of rapamycin inhibitor. Conclusion This case study indicates that combined treatment with everolimus and fulvestrant might be a viable option for the treatment of metastatic breast cancer patients who are HER2 positive and carry a PIK3CA gene mutation but are resistant to anti-HER2 therapy and classical chemotherapeutic agents. Further prospective randomized trials are needed to confirm this finding. PMID:27445490

  20. Proteomic analysis reveals GIT1 as a novel mTOR complex component critical for mediating astrocyte survival.

    PubMed

    Smithson, Laura J; Gutmann, David H

    2016-06-15

    As a critical regulator of cell growth, the mechanistic target of rapamycin (mTOR) protein operates as part of two molecularly and functionally distinct complexes. Herein, we demonstrate that mTOR complex molecular composition varies in different somatic tissues. In astrocytes and neural stem cells, we identified G-protein-coupled receptor kinase-interacting protein 1 (GIT1) as a novel mTOR-binding protein, creating a unique mTOR complex lacking Raptor and Rictor. Moreover, GIT1 binding to mTOR is regulated by AKT activation and is essential for mTOR-mediated astrocyte survival. Together, these data reveal that mTOR complex function is partly dictated by its molecuflar composition in different cell types. PMID:27340174

  1. Gβγ interacts with mTOR and promotes its activation

    SciTech Connect

    Robles-Molina, Evelyn; Dionisio-Vicuña, Misael; Guzmán-Hernández, María Luisa; Reyes-Cruz, Guadalupe; Vázquez-Prado, José

    2014-02-07

    Highlights: • Gβγ interacts with mTOR kinase domain via a mechanism sensitive to chronic treatment with rapamycin. • Gβγ interacts with mTORC1 and mTORC2 which correlates with its ability to promote mTORC1 and mTORC2 signaling. • Gβγ heterodimers containing different Gβ subunits, except Gβ{sub 4}, interact with mTOR. - Abstract: Diverse G protein-coupled receptors depend on Gβγ heterodimers to promote cell polarization and survival via direct activation of PI3Kγ and potentially other effectors. These events involve full activation of AKT via its phosphorylation at Ser473, suggesting that mTORC2, the kinase that phosphorylates AKT at Ser473, is activated downstream of Gβγ. Thus, we tested the hypothesis that Gβγ directly contributes to mTOR signaling. Here, we demonstrate that endogenous mTOR interacts with Gβγ. Cell stimulation with serum modulates Gβγ interaction with mTOR. The carboxyl terminal region of mTOR, expressed as a GST-fusion protein, including the serine/threonine kinase domain, binds Gβγ heterodimers containing different Gβ subunits, except Gβ{sub 4}. Both, mTORC1 and mTORC2 complexes interact with Gβ{sub 1}γ{sub 2} which promotes phosphorylation of their respective substrates, p70S6K and AKT. In addition, chronic treatment with rapamycin, a condition known to interfere with assembly of mTORC2, reduces the interaction between Gβγ and mTOR and the phosphorylation of AKT; whereas overexpression of Gαi interfered with the effect of Gβγ as promoter of p70S6K and AKT phosphorylation. Altogether, our results suggest that Gβγ positively regulates mTOR signaling via direct interactions and provide further support to emerging strategies based on the therapeutical potential of inhibiting different Gβγ signaling interfaces.

  2. Discovery of mammalian target of rapamycin (mTOR) kinase inhibitor CC-223.

    PubMed

    Mortensen, Deborah S; Perrin-Ninkovic, Sophie M; Shevlin, Graziella; Zhao, Jingjing; Packard, Garrick; Bahmanyar, Sogole; Correa, Matthew; Elsner, Jan; Harris, Roy; Lee, Branden G S; Papa, Patrick; Parnes, Jason S; Riggs, Jennifer R; Sapienza, John; Tehrani, Lida; Whitefield, Brandon; Apuy, Julius; Bisonette, René R; Gamez, James C; Hickman, Matt; Khambatta, Godrej; Leisten, Jim; Peng, Sophie X; Richardson, Samantha J; Cathers, Brian E; Canan, Stacie S; Moghaddam, Mehran F; Raymon, Heather K; Worland, Peter; Narla, Rama Krishna; Fultz, Kimberly E; Sankar, Sabita

    2015-07-01

    We report here the synthesis and structure-activity relationship (SAR) of a novel series of mammalian target of rapamycin (mTOR) kinase inhibitors. A series of 4,6- or 1,7-disubstituted-3,4-dihydropyrazino[2,3-b]pyrazine-2(1H)-ones were optimized for in vivo efficacy. These efforts resulted in the identification of compounds with excellent mTOR kinase inhibitory potency, with exquisite kinase selectivity over the related lipid kinase PI3K. The improved PK properties of this series allowed for exploration of in vivo efficacy and ultimately the selection of CC-223 for clinical development. PMID:26083478

  3. CC-223, a Potent and Selective Inhibitor of mTOR Kinase: In Vitro and In Vivo Characterization.

    PubMed

    Mortensen, Deborah S; Fultz, Kimberly E; Xu, Shuichan; Xu, Weiming; Packard, Garrick; Khambatta, Godrej; Gamez, James C; Leisten, Jim; Zhao, Jingjing; Apuy, Julius; Ghoreishi, Kamran; Hickman, Matt; Narla, Rama Krishna; Bissonette, Rene; Richardson, Samantha; Peng, Sophie X; Perrin-Ninkovic, Sophie; Tran, Tam; Shi, Tao; Yang, Wen Qing; Tong, Zeen; Cathers, Brian E; Moghaddam, Mehran F; Canan, Stacie S; Worland, Peter; Sankar, Sabita; Raymon, Heather K

    2015-06-01

    mTOR is a serine/threonine kinase that regulates cell growth, metabolism, proliferation, and survival. mTOR complex-1 (mTORC1) and mTOR complex-2 (mTORC2) are critical mediators of the PI3K-AKT pathway, which is frequently mutated in many cancers, leading to hyperactivation of mTOR signaling. Although rapamycin analogues, allosteric inhibitors that target only the mTORC1 complex, have shown some clinical activity, it is hypothesized that mTOR kinase inhibitors, blocking both mTORC1 and mTORC2 signaling, will have expanded therapeutic potential. Here, we describe the preclinical characterization of CC-223. CC-223 is a potent, selective, and orally bioavailable inhibitor of mTOR kinase, demonstrating inhibition of mTORC1 (pS6RP and p4EBP1) and mTORC2 [pAKT(S473)] in cellular systems. Growth inhibitory activity was demonstrated in hematologic and solid tumor cell lines. mTOR kinase inhibition in cells, by CC-223, resulted in more complete inhibition of the mTOR pathway biomarkers and improved antiproliferative activity as compared with rapamycin. Growth inhibitory activity and apoptosis was demonstrated in a panel of hematologic cancer cell lines. Correlative analysis revealed that IRF4 expression level associates with resistance, whereas mTOR pathway activation seems to associate with sensitivity. Treatment with CC-223 afforded in vivo tumor biomarker inhibition in tumor-bearing mice, after a single oral dose. CC-223 exhibited dose-dependent tumor growth inhibition in multiple solid tumor xenografts. Significant inhibition of mTOR pathway markers pS6RP and pAKT in CC-223-treated tumors suggests that the observed antitumor activity of CC-223 was mediated through inhibition of both mTORC1 and mTORC2. CC-223 is currently in phase I clinical trials. PMID:25855786

  4. mTOR ensures increased release and reduced uptake of the organic osmolyte taurine under hypoosmotic conditions in mouse fibroblasts.

    PubMed

    Lambert, Ian Henry; Jensen, Jane Vendelbo; Pedersen, Per Amstrup

    2014-06-01

    Mammalian target of rapamycin (mTOR) is a serine/threonine kinase that modulates translation in response to growth factors and alterations in nutrient availability following hypoxia and DNA damage. Here we demonstrate that mTOR activity in Ehrlich Lettré ascites (ELA) cells is transiently increased within minutes following osmotic cell swelling and that inhibition of phosphatidylinositol-3-phosphatase (PTEN) counteracts the upstream phosphatidylinositol kinase and potentiates mTOR activity. PTEN inhibition concomitantly potentiates swelling-induced taurine release via the volume-sensitive transporter for organic osmolytes and anion channels (VSOAC) and enhances swelling-induced inhibition of taurine uptake via the taurine-specific transporter (TauT). Chronic osmotic stress, i.e., exposure to hypotonic or hypertonic media for 24 h, reduces and increases mTOR activity in ELA cells, respectively. Using rapamycin, we demonstrate that mTOR inhibition is accompanied by reduction in TauT activity and increase in VSOAC activity in cells expressing high (NIH3T3 fibroblasts) or low (ELA) amounts of mTOR protein. The effect of mTOR inhibition on TauT activity reflects reduced TauT mRNA, TauT protein abundance, and an overall reduction in protein synthesis, whereas the effect on VSOAC is mimicked by catalase inhibition and correlates with reduced catalase mRNA abundance. Hence, mTOR activity favors loss of taurine following hypoosmotic cell swelling, i.e., release via VSOAC and uptake via TauT during acute hypotonic exposure is potentiated and reduced, respectively, by phosphorylation involving mTOR and/or the kinases upstream to mTOR. Decrease in TauT activity during chronic hypotonic exposure, on the other hand, involves reduction in expression/activity of TauT and enzymes in antioxidative defense. PMID:24696147

  5. mTOR Ser-2481 autophosphorylation monitors mTORC-specific catalytic activity and clarifies rapamycin mechanism of action.

    PubMed

    Soliman, Ghada A; Acosta-Jaquez, Hugo A; Dunlop, Elaine A; Ekim, Bilgen; Maj, Nicole E; Tee, Andrew R; Fingar, Diane C

    2010-03-12

    The mammalian target of rapamycin (mTOR) Ser/Thr kinase signals in at least two multiprotein complexes distinguished by their different partners and sensitivities to rapamycin. Acute rapamycin inhibits signaling by mTOR complex 1 (mTORC1) but not mTOR complex 2 (mTORC2), which both promote cell growth, proliferation, and survival. Although mTORC2 regulation remains poorly defined, diverse cellular mitogens activate mTORC1 signaling in a manner that requires sufficient levels of amino acids and cellular energy. Before the identification of distinct mTOR complexes, mTOR was reported to autophosphorylate on Ser-2481 in vivo in a rapamycin- and amino acid-insensitive manner. These results suggested that modulation of mTOR intrinsic catalytic activity does not universally underlie mTOR regulation. Here we re-examine the regulation of mTOR Ser-2481 autophosphorylation (Ser(P)-2481) in vivo by studying mTORC-specific Ser(P)-2481 in mTORC1 and mTORC2, with a primary focus on mTORC1. In contrast to previous work, we find that acute rapamycin and amino acid withdrawal markedly attenuate mTORC1-associated mTOR Ser(P)-2481 in cycling cells. Although insulin stimulates both mTORC1- and mTORC2-associated mTOR Ser(P)-2481 in a phosphatidylinositol 3-kinase-dependent manner, rapamycin acutely inhibits insulin-stimulated mTOR Ser(P)-2481 in mTORC1 but not mTORC2. By interrogating diverse mTORC1 regulatory input, we find that without exception mTORC1-activating signals promote, whereas mTORC1-inhibitory signals decrease mTORC1-associated mTOR Ser(P)-2481. These data suggest that mTORC1- and likely mTORC2-associated mTOR Ser-2481 autophosphorylation directly monitors intrinsic mTORC-specific catalytic activity and reveal that rapamycin inhibits mTORC1 signaling in vivo by reducing mTORC1 catalytic activity. PMID:20022946

  6. Degradation of Tiam1 by Casein Kinase 1 and the SCFβTrCP Ubiquitin Ligase Controls the Duration of mTOR-S6K Signaling*

    PubMed Central

    Magliozzi, Roberto; Kim, Jihoon; Low, Teck Yew; Heck, Albert J. R.; Guardavaccaro, Daniele

    2014-01-01

    Tiam1 (T-cell lymphoma invasion and metastasis 1) is a guanine nucleotide exchange factor that specifically controls the activity of the small GTPase Rac, a key regulator of cell adhesion, proliferation, and survival. Here, we report that in response to mitogens, Tiam1 is degraded by the ubiquitin-proteasome system via the SCFβTrCP ubiquitin ligase. Mitogenic stimulation triggers the binding of Tiam1 to the F-box protein βTrCP via its degron sequence and subsequent Tiam1 ubiquitylation and proteasomal degradation. The proteolysis of Tiam1 is prevented by βTrCP silencing, inhibition of CK1 and MEK, or mutation of the Tiam1 degron site. Expression of a stable Tiam1 mutant that is unable to interact with βTrCP results in sustained activation of the mTOR/S6K signaling and increased apoptotic cell death. We propose that the SCFβTrCP-mediated degradation of Tiam1 controls the duration of the mTOR-S6K signaling pathway in response to mitogenic stimuli. PMID:25124033

  7. Hyperactive mTOR signals in the proopiomelanocortin-expressing hippocampal neurons cause age-dependent epilepsy and premature death in mice.

    PubMed

    Matsushita, Yuki; Sakai, Yasunari; Shimmura, Mitsunori; Shigeto, Hiroshi; Nishio, Miki; Akamine, Satoshi; Sanefuji, Masafumi; Ishizaki, Yoshito; Torisu, Hiroyuki; Nakabeppu, Yusaku; Suzuki, Akira; Takada, Hidetoshi; Hara, Toshiro

    2016-01-01

    Epilepsy is a frequent comorbidity in patients with focal cortical dysplasia (FCD). Recent studies utilizing massive sequencing data identified subsets of genes that are associated with epilepsy and FCD. AKT and mTOR-related signals have been recently implicated in the pathogenic processes of epilepsy and FCD. To clarify the functional roles of the AKT-mTOR pathway in the hippocampal neurons, we generated conditional knockout mice harboring the deletion of Pten (Pten-cKO) in Proopiomelanocortin-expressing neurons. The Pten-cKO mice developed normally until 8 weeks of age, then presented generalized seizures at 8-10 weeks of age. Video-monitored electroencephalograms detected paroxysmal discharges emerging from the cerebral cortex and hippocampus. These mice showed progressive hypertrophy of the dentate gyrus (DG) with increased expressions of excitatory synaptic markers (Psd95, Shank3 and Homer). In contrast, the expression of inhibitory neurons (Gad67) was decreased at 6-8 weeks of age. Immunofluorescence studies revealed the abnormal sprouting of mossy fibers in the DG of the Pten-cKO mice prior to the onset of seizures. The treatment of these mice with an mTOR inhibitor rapamycin successfully prevented the development of seizures and reversed these molecular phenotypes. These data indicate that the mTOR pathway regulates hippocampal excitability in the postnatal brain. PMID:26961412

  8. Hyperactive mTOR signals in the proopiomelanocortin-expressing hippocampal neurons cause age-dependent epilepsy and premature death in mice

    PubMed Central

    Matsushita, Yuki; Sakai, Yasunari; Shimmura, Mitsunori; Shigeto, Hiroshi; Nishio, Miki; Akamine, Satoshi; Sanefuji, Masafumi; Ishizaki, Yoshito; Torisu, Hiroyuki; Nakabeppu, Yusaku; Suzuki, Akira; Takada, Hidetoshi; Hara, Toshiro

    2016-01-01

    Epilepsy is a frequent comorbidity in patients with focal cortical dysplasia (FCD). Recent studies utilizing massive sequencing data identified subsets of genes that are associated with epilepsy and FCD. AKT and mTOR-related signals have been recently implicated in the pathogenic processes of epilepsy and FCD. To clarify the functional roles of the AKT-mTOR pathway in the hippocampal neurons, we generated conditional knockout mice harboring the deletion of Pten (Pten-cKO) in Proopiomelanocortin-expressing neurons. The Pten-cKO mice developed normally until 8 weeks of age, then presented generalized seizures at 8–10 weeks of age. Video-monitored electroencephalograms detected paroxysmal discharges emerging from the cerebral cortex and hippocampus. These mice showed progressive hypertrophy of the dentate gyrus (DG) with increased expressions of excitatory synaptic markers (Psd95, Shank3 and Homer). In contrast, the expression of inhibitory neurons (Gad67) was decreased at 6–8 weeks of age. Immunofluorescence studies revealed the abnormal sprouting of mossy fibers in the DG of the Pten-cKO mice prior to the onset of seizures. The treatment of these mice with an mTOR inhibitor rapamycin successfully prevented the development of seizures and reversed these molecular phenotypes. These data indicate that the mTOR pathway regulates hippocampal excitability in the postnatal brain. PMID:26961412

  9. Combined inhibition of MEK and mTOR has a synergic effect on angiosarcoma tumorgrafts.

    PubMed

    Andersen, Nicholas J; Boguslawski, Elissa B; Kuk, Cynthia Y; Chambers, Christopher M; Duesbery, Nicholas S

    2015-07-01

    Angiosarcoma (AS) is a rare neoplasm of endothelial origin that has limited treatment options and poor five-year survival. Using tumorgraft models, we previously showed that AS is sensitive to small-molecule inhibitors that target mitogen-activated/extracellular-signal-regulated protein kinase kinases 1 and 2 (MEK). The objective of this study was to identify drugs that combine with MEK inhibitors to more effectively inhibit AS growth. We examined the in vitro synergy between the MEK inhibitor PD0325901 and inhibitors of eleven common cancer pathways in melanoma cell lines and canine angiosarcoma cell isolates. Combination indices were calculated using the Chou-Talalay method. Optimized combination therapies were evaluated in vivo for toxicity and efficacy using canine angiosarcoma tumorgrafts. Among the drugs we tested, rapamycin stood out because it showed strong synergy with PD0325901 at nanomolar concentrations. We observed that angiosarcomas are insensitive to mTOR inhibition. However, treatment with nanomolar levels of mTOR inhibitor renders these cells as sensitive to MEK inhibition as a melanoma cell line with mutant BRAF. Similar results were observed in B-Raf wild-type melanoma cells as well as in vivo, where treatment of canine AS tumorgrafts with MEK and mTOR inhibitors was more effective than monotherapy. Our data show that a low dose of an mTOR inhibitor can dramatically enhance angiosarcoma and melanoma response to MEK inhibition, potentially widening the field of applications for MEK-targeted therapy. PMID:25955301

  10. mTOR Controls Ovarian Follicle Growth by Regulating Granulosa Cell Proliferation

    PubMed Central

    Yu, James; Yaba, Aylin; Kasiman, Corinna; Thomson, Travis; Johnson, Joshua

    2011-01-01

    We have shown that inhibition of mTOR in granulosa cells and ovarian follicles results in compromised granulosa proliferation and reduced follicle growth. Further analysis here using spontaneously immortalized rat granulosa cells has revealed that mTOR pathway activity is enhanced during M-phase of the cell cycle. mTOR specific phosphorylation of p70S6 kinase and 4E-BP, and expression of Raptor are all enhanced during M-phase. The predominant effect of mTOR inhibition by the specific inhibitor Rapamycin (RAP) was a dose-responsive arrest in the G1 cell cycle stage. The fraction of granulosa cells that continued to divide in the presence of RAP exhibited a dose-dependent increase in aberrant mitotic figures known as anaphase bridges. Strikingly, estradiol consistently decreased the incidence of aberrant mitotic figures. In mice treated with RAP, the mitotic index was reduced compared to controls, and a similar increase in aberrant mitotic events was noted. RAP injected during a superovulation regime resulted in a dose-dependent reduction in the numbers of eggs ovulated. Implications for the real-time regulation of follicle growth and dominance, including the consequences of increased numbers of aneuploid granulosa cells, are discussed. PMID:21750711

  11. Combined inhibition of MEK and mTOR has a synergic effect on angiosarcoma tumorgrafts

    PubMed Central

    ANDERSEN, NICHOLAS J.; BOGUSLAWSKI, ELISSA B.; KUK, CYNTHIA Y.; CHAMBERS, CHRISTOPHER M.; DUESBERY, NICHOLAS S.

    2015-01-01

    Angiosarcoma (AS) is a rare neoplasm of endothelial origin that has limited treatment options and poor five-year survival. Using tumorgraft models, we previously showed that AS is sensitive to small-molecule inhibitors that target mitogen-activated/extracellular-signal-regulated protein kinase kinases 1 and 2 (MEK). The objective of this study was to identify drugs that combine with MEK inhibitors to more effectively inhibit AS growth. We examined the in vitro synergy between the MEK inhibitor PD0325901 and inhibitors of eleven common cancer pathways in melanoma cell lines and canine angiosarcoma cell isolates. Combination indices were calculated using the Chou-Talalay method. Optimized combination therapies were evaluated in vivo for toxicity and efficacy using canine angiosarcoma tumorgrafts. Among the drugs we tested, rapamycin stood out because it showed strong synergy with PD0325901 at nanomolar concentrations. We observed that angiosarcomas are insensitive to mTOR inhibition. However, treatment with nanomolar levels of mTOR inhibitor renders these cells as sensitive to MEK inhibition as a melanoma cell line with mutant BRAF. Similar results were observed in B-Raf wild-type melanoma cells as well as in vivo, where treatment of canine AS tumorgrafts with MEK and mTOR inhibitors was more effective than monotherapy. Our data show that a low dose of an mTOR inhibitor can dramatically enhance angiosarcoma and melanoma response to MEK inhibition, potentially widening the field of applications for MEK-targeted therapy. PMID:25955301

  12. mTOR regulates MAPKAPK2 translation to control the senescence-associated secretory phenotype

    PubMed Central

    Herranz, Nicolás; Gallage, Suchira; Mellone, Massimiliano; Wuestefeld, Torsten; Klotz, Sabrina; Hanley, Christopher J.; Raguz, Selina; Acosta, Juan Carlos; Innes, Andrew J; Banito, Ana; Georgilis, Athena; Montoya, Alex; Wolter, Katharina; Dharmalingam, Gopuraja; Faull, Peter; Carroll, Thomas; Martínez-Barbera, Juan Pedro; Cutillas, Pedro; Reisinger, Florian; Heikenwalder, Mathias; Miller, Richard A.; Withers, Dominic; Zender, Lars; Thomas, Gareth J.; Gil, Jesús

    2015-01-01

    Senescent cells secrete a combination of factors collectively known as the senescence-associated secretory phenotype (SASP). The SASP reinforces senescence and activates an immune surveillance response but it can also display pro-tumorigenic properties and contribute to age-related pathologies. In a drug screen to find novel SASP regulators, we uncovered the mTOR inhibitor rapamycin as a potent SASP suppressor. Here we report a mechanism by which mTOR controls the SASP by differentially regulating the translation of the MK2/MAPKAPK2 kinase through 4EBP1. In turn, MAPKAPK2 phosphorylates the RNA binding protein ZFP36L1 during senescence, inhibiting its ability to degrade the transcripts of numerous SASP components. Consequently, mTOR inhibition or constitutive activation of ZFP36L1 impairs the non-cell-autonomous effects of senescent cells both in tumour-suppressive and promoting-promoting contexts. Altogether, our results place regulation of the SASP as a key mechanism by which mTOR could influence cancer, age-related diseases and immune responses. PMID:26280535

  13. Interaction of mTOR and Erk1/2 signaling to regulate oligodendrocyte differentiation.

    PubMed

    Dai, JinXiang; Bercury, Kathryn K; Macklin, Wendy B

    2014-12-01

    A multitude of factors regulate oligodendrocyte differentiation and remyelination, and to elucidate the mechanisms underlying this process, we analyzed the interactions of known signaling pathways involved in these processes. Previous work from our lab and others shows that Akt, mTOR, and Erk 1/2 are major signaling pathways regulating oligodendrocyte differentiation and myelination in vitro and in vivo. However, the relative contribution of the different pathways has been difficult to establish because the impact of inhibiting one pathway in in vitro cell culture models or in vivo may alter signaling through the other pathway. These studies were undertaken to clarify the interactions between these major pathways and understand more specifically the crosstalk between them. Oligodendrocyte differentiation in vitro required Akt, mTOR, and Erk 1/2 signaling, as inhibition of Akt, mTOR, or Erk 1/2 resulted in a significant decrease of myelin basic protein mRNA and protein expression. Interestingly, while inhibition of the Erk1/2 pathway had little impact on Akt/mTOR signaling, inhibition of the Akt/mTOR pathways significantly increased Erk1/2 signaling, although not enough to overcome the loss of Akt/mTOR signaling in the regulation of oligodendrocyte differentiation. Furthermore, such crosstalk was also noted in an in vivo context, after mTOR inhibition by rapamycin treatment of perinatal pups. GLIA 2014;62:2096-2109. PMID:25060812

  14. Regulation of mTOR Pathway in Exercise-induced Cardiac Hypertrophy.

    PubMed

    Liao, J; Li, Y; Zeng, F; Wu, Y

    2015-05-01

    This study was designed to examine whether the mTOR signaling pathway would respond to long-term different intensity exercises and to observe the impact of exercise upon possible cardiac damage. Male Sprague Dawley rats were randomly divided into control group, moderate-intensity exercise group and high-intensity exercise group, and each exercise group had 4 observation time points (1-24 h). Exercise training lasted 8 weeks with a 2-day break for each week. Serum cTnI was measured by ELSIA and myocardium histology was assessed by HE and HBFP. The expressions of Akt, mTOR, p70(S6K) and their phosphorylated forms were determined by western-blot. Both exercises were effective at inducing cardiac hypertrophy, wherein magnitude increased with exercise intensity. The significantly high level of serum cTnI in the high-intensity group was accompanied by obvious myocellular abnormalities and ischemia in the myocardium. Significant activation of Akt, mTOR and p70(S6K) were observed in the moderate exercise group but not in the high-intensity exercise group. Results indicate that long-term high-intensity exercise training would induce cardiac hypertrophy accompanied by damage to the heart, entailing a risk of pathological changes. There might be a pivotal regulatory role of the mTOR signaling pathway on cardiac hypertrophy after long-term moderate exercise, but not after high-intensity exercise. PMID:25607521

  15. mTOR regulates MAPKAPK2 translation to control the senescence-associated secretory phenotype.

    PubMed

    Herranz, Nicolás; Gallage, Suchira; Mellone, Massimiliano; Wuestefeld, Torsten; Klotz, Sabrina; Hanley, Christopher J; Raguz, Selina; Acosta, Juan Carlos; Innes, Andrew J; Banito, Ana; Georgilis, Athena; Montoya, Alex; Wolter, Katharina; Dharmalingam, Gopuraja; Faull, Peter; Carroll, Thomas; Martínez-Barbera, Juan Pedro; Cutillas, Pedro; Reisinger, Florian; Heikenwalder, Mathias; Miller, Richard A; Withers, Dominic; Zender, Lars; Thomas, Gareth J; Gil, Jesús

    2015-09-01

    Senescent cells secrete a combination of factors collectively known as the senescence-associated secretory phenotype (SASP). The SASP reinforces senescence and activates an immune surveillance response, but it can also show pro-tumorigenic properties and contribute to age-related pathologies. In a drug screen to find new SASP regulators, we uncovered the mTOR inhibitor rapamycin as a potent SASP suppressor. Here we report a mechanism by which mTOR controls the SASP by differentially regulating the translation of the MK2 (also known as MAPKAPK2) kinase through 4EBP1. In turn, MAPKAPK2 phosphorylates the RNA-binding protein ZFP36L1 during senescence, inhibiting its ability to degrade the transcripts of numerous SASP components. Consequently, mTOR inhibition or constitutive activation of ZFP36L1 impairs the non-cell-autonomous effects of senescent cells in both tumour-suppressive and tumour-promoting contexts. Altogether, our results place regulation of the SASP as a key mechanism by which mTOR could influence cancer, age-related diseases and immune responses. PMID:26280535

  16. Novel mTOR inhibitory activity of ciclopirox enhances parthenolide antileukemia activity

    PubMed Central

    Sen, Siddhartha; Hassane, Duane C.; Corbett, Cheryl; Becker, Michael W.; Jordan, Craig T.; Guzman, Monica L.

    2013-01-01

    Ciclopirox, an antifungal agent commonly used for the dermatologic treatment of mycoses, has been shown recently to have antitumor properties. Although the exact mechanism of ciclopirox is unclear, its antitumor activity has been attributed to iron chelation and inhibition of the translation initiation factor eIF5A. In this study, we identify a novel function of ciclopirox in the inhibition of mTOR. As with other mTOR inhibitors, we show that ciclopirox significantly enhances the ability of the established preclinical antileukemia compound, parthenolide, to target acute myeloid leukemia. The combination of parthenolide and ciclopirox demonstrates greater toxicity against acute myeloid leukemia than treatment with either compound alone. We also demonstrate that the ability of ciclopirox to inhibit mTOR is specific to ciclopirox because neither iron chelators nor other eIF5A inhibitors affect mTOR activity, even at high doses. We have thus identified a novel function of ciclopirox that might be important for its antileukemic activity. PMID:23660068

  17. Modulation of mTOR effector phosphoproteins in blood basophils from allergic patients.

    PubMed

    Gernez, Yael; Tirouvanziam, Rabindra; Reshamwala, Neha; Yu, Grace; Weldon, Brittany C; Galli, Stephen J; Herzenberg, Leonore A; Nadeau, Kari C

    2012-06-01

    The mammalian target of rapamycin (mTOR) pathway contributes to various immunoinflammatory processes. Yet, its potential involvement in basophil responses in allergy remains unclear. In this pilot study, we quantified two key mTOR effector phosphoproteins, the eukaryotic initiation factor 4E (peIF4E) and S6 ribosomal protein (pS6rp), in blood basophils from nut allergy patients (NA, N = 16) and healthy controls (HC, N = 13). Without stimulation in vitro, basophil peIF4E levels were higher in NA than HC subjects (P = 0.014). Stimulation with nut (offending) but not chicken / rice (non-offending) extract increased basophil peIF4E and pS6rp levels (+32%, P = 0.018, and +98%, P = 0.0026, respectively) in NA but not HC subjects, concomitant with increased surface levels of CD203c and CD63, both known to reflect basophil activation. Pre-treatment with the mTOR inhibitor rapamycin decreased pS6rp and CD203c responses in nut extract-stimulated basophils in NA subjects. Thus, basophil responses to offending allergens are associated with modulation of mTOR effector phosphoproteins. PMID:22350221

  18. Trichomonas vaginalis metalloproteinase induces mTOR cleavage of SiHa cells.

    PubMed

    Quan, Juan-Hua; Choi, In-Wook; Yang, Jung-Bo; Zhou, Wei; Cha, Guang-Ho; Zhou, Yu; Ryu, Jae-Sook; Lee, Young-Ha

    2014-12-01

    Trichomonas vaginalis secretes a number of proteases which are suspected to be the cause of pathogenesis; however, little is understood how they manipulate host cells. The mammalian target of rapamycin (mTOR) regulates cell growth, cell proliferation, cell motility, cell survival, protein synthesis, and transcription. We detected various types of metalloproteinases including GP63 protein from T. vaginalis trophozoites, and T. vaginalis GP63 metalloproteinase was confirmed by sequencing and western blot. When SiHa cells were stimulated with live T. vaginalis, T. vaginalis excretory-secretory products (ESP) or T. vaginalis lysate, live T. vaginalis and T. vaginalis ESP induced the mTOR cleavage in both time- and parasite load-dependent manner, but T. vaginalis lysate did not. Pretreatment of T. vaginalis with a metalloproteinase inhibitor, 1,10-phenanthroline, completely disappeared the mTOR cleavage in SiHa cells. Collectively, T. vaginalis metallopeptidase induces host cell mTOR cleavage, which may be related to survival of the parasite. PMID:25548410

  19. mTOR masters monocytic myeloid-derived suppressor cells in mice with allografts or tumors

    PubMed Central

    Wu, Tingting; Zhao, Yang; Wang, Hao; Li, yang; Shao, Lijuan; Wang, Ruoyu; Lu, Jun; Yang, Zhongzhou; Wang, Junjie; Zhao, Yong

    2016-01-01

    CD11b+ Gr1+ myeloid-derived suppressor cells (MDSCs) play critical roles in controlling the processes of tumors, infections, autoimmunity and graft rejection. Immunosuppressive drug rapamycin (RPM), targeting on the key cellular metabolism molecule mTOR, is currently used in clinics to treat patients with allo-grafts, autoimmune diseases and tumors. However, the effect of RPM on MDSCs has not been studied. RPM significantly decreases the cell number and the immunosuppressive ability on T cells of CD11b+ Ly6Chigh monocytic MDSCs (M-MDSCs) in both allo-grafts-transplanted and tumor-bearing mice respectively. Mice with a myeloid-specific deletion of mTOR have poor M-MDSCs after grafting with allo-skin tissue or a tumor. Grafting of allo-skin or tumors significantly activates glycolysis pathways in myeloid precursor cells in bone marrow, which is inhibited by RPM or mTOR deletion. 2-deoxyglucose (2-DG), an inhibitor of the glycolytic pathway, inhibits M-MDSC differentiation from precursors, while enhancing glycolysis by metformin significantly rescues the RPM-caused deficiency of M-MDSCs. Therefore, we offer evidence supporting that mTOR is an intrinsic factor essential for the differentiation and immunosuppressive function of M-MDSCs and that these metabolism-relevant medicines may impact MDSCs-mediated immunosuppression or immune tolerance induction, which is of considerable clinical importance in treating graft rejection, autoimmune diseases and cancers. PMID:26833095

  20. Flcn-deficient renal cells are tumorigenic and sensitive to mTOR suppression

    PubMed Central

    Li, Yan; Schoen, Susan; Xiao, Guang-Qian; Li, Xueying; Teh, Bin Tean; Wu, Guan; Chen, Jindong

    2015-01-01

    Deficiency of tumor suppressor FLCN leads to the activation of the mTOR signaling pathway in human BHD-associated renal cell carcinomas (RCC). We have previously developed a renal distal tubule-collecting duct-Henle's loop-specific Flcn knockout (KO) mouse model (Flcnflox/flox/Ksp-Cre). This mouse model can only survive for three weeks after birth due to the development of polycystic kidney and uremia. Whether these cystic solid hyperplasia changes seen in those KO mice are tumorigenic or malignant is unknown. In this study, we demonstrated that genetic disruption of Flcn in mouse kidney distal tubule cells could lead to tumorigenic transformation of these cells to develop allograft tumors with an aggressive histologic phenotype. Consistent with previous reports, we showed that the mTOR pathway plays an important role in the growth of these Flcn-deficient allograft and human UOK 257-1 xenograft tumors. We further demonstrated that the mTOR inhibitor, sirolimus, suppresses the tumor's growth, suggesting that mTOR inhibitors might be effective in control of FLCN-deficient RCC, especially in BHD renal tumorigenesis. PMID:26418749

  1. mTOR inhibition improves fibroblast growth factor receptor targeting in hepatocellular carcinoma

    PubMed Central

    Scheller, T; Hellerbrand, C; Moser, C; Schmidt, K; Kroemer, A; Brunner, S M; Schlitt, H J; Geissler, E K; Lang, S A

    2015-01-01

    Background: Systemic therapy has proven only marginal effects in hepatocellular carcinoma (HCC) so far. The aim of this study was to evaluate the effect of targeting fibroblast growth factor receptor (FGFR) on tumour and stromal cells in HCC models. Methods: Human and murine HCC cells, endothelial cells (ECs), vascular smooth muscle cells (VSMCs), hepatic stellate cells (HSCs), human HCC samples, FGFR inhibitor BGJ398 and mammalian target of rapamycin (mTOR) inhibitor rapamycin were used. Effects on growth, motility, signalling and angiogenic markers were determined. In vivo subcutaneous and syngeneic orthotopic tumour models were used. Results: In tumour cells and ECs, targeting FGFR showed significant inhibitory effects on signalling and motility. Minor effects of FGFR inhibition were observed on VSMCs and HSCs, which were significantly enhanced by combining FGFR and mTOR blockade. In vivo daily (5 mg kg−1) treatment with BGJ398 led to a significant growth inhibition in subcutaneous tumour models, but only a combination of FGFR and mTOR blockade impaired tumour growth in the orthotopic model. This was paralleled by reduced tumour cell proliferation, vascularisation, pericytes and increased apoptosis. Conclusions: Targeting FGFR with BGJ398 affects tumour cells and ECs, whereas only a combination with mTOR inhibition impairs recruitment of VSMCs and HSCs. Therefore, this study provides evidence for combined FGFR/mTOR inhibition in HCC. PMID:25688743

  2. Fluoxetine regulates mTOR signalling in a region-dependent manner in depression-like mice

    PubMed Central

    Liu, Xiao-Long; Luo, Liu; Mu, Rong-Hao; Liu, Bin-Bin; Geng, Di; Liu, Qing; Yi, Li-Tao

    2015-01-01

    Previous studies have demonstrated that the mammalian target of rapamycin (mTOR) signaling pathway has an important role in ketamine-induced, rapid antidepressant effects despite the acute administration of fluoxetine not affecting mTOR phosphorylation in the brain. However, the effects of long-term fluoxetine treatment on mTOR modulation have not been assessed to date. In the present study, we examined whether fluoxetine, a type of commonly used antidepressant agent, alters mTOR signaling following chronic administration in different brain regions, including the frontal cortex, hippocampus, amygdala and hypothalamus. We also investigated whether fluoxetine enhanced synaptic protein levels in these regions via the activation of the mTOR signaling pathway and its downstream regulators, p70S6K and 4E-BP-1. The results indicated that chronic fluoxetine treatment attenuated the chronic, unpredictable, mild stress (CUMS)-induced mTOR phosphorylation reduction in the hippocampus and amygdala of mice but not in the frontal cortex or the hypothalamus. Moreover, the CUMS-decreased PSD-95 and synapsin I levels were reversed by fluoxetine, and these effects were blocked by rapamycin only in the hippocampus. In conclusion, our findings suggest that chronic treatment with fluoxetine can induce synaptic protein expression by activating the mTOR signaling pathway in a region-dependent manner and mainly in the hippocampus. PMID:26522512

  3. Screening mTOR siRNA based on bioinformatics and detecting the transcription by the gold nanoparticle beacon

    NASA Astrophysics Data System (ADS)

    Tian, Caiping; Ma, Yi; Li, Siwen; Gu, Yueqing

    2014-09-01

    Mammalian target of rapamycin (mTOR) as a key protein in PI3K-AKT-mTOR signaling pathway ,plays an important role in the tumor growth. The small interfering RNA (siRNA) of mTOR would decrease the expression of mTOR protein. In this study, we screened the mTOR siRNA sequence using MATLAB software and ascertained it based on BLAST. Then we imported it with the aid of Lipofectamine2000 into MCF-7 cancer cells where mTOR is over expression .And then we used a special hairpin deoxyribonucleic acid (DNA) for combining with the human mTOR mRNA to functionalize gold nanoparticles, which served as a molecule beacon for detecting human mTOR mRNA transcription. Laser scanning confocal microscope and Flow Cytometry data showed that the quenching efficiency was up to 90%,which are consistent with the RT-PCR measurement and Western. Compared to the previous approaches, this beacon has advantages of higher target to background ratio of detection. The strategy reported in this study is a promising approach for the intracellular measurement of the result of siRNA or protein expression in living cells, and has great potential in the study of drug screening and discovery.

  4. Stimulation of the intestinal phosphate transporter SLC34A2 by the protein kinase mTOR.

    PubMed

    Shojaiefard, Manzar; Lang, Florian

    2006-07-14

    Adequate phosphate homeostasis is of critical importance for a wide variety of functions including bone mineralization and energy metabolism. Phosphate balance is a function of intestinal absorption and renal elimination, which are both under tight hormonal control. Intestinal phosphate absorption is accomplished by the Na(+), phosphate cotransporter NaPi IIb (SLC34A2). Signaling mechanisms mediating hormonal regulation of SLC34A2 are incompletely understood. The mammalian target of rapamycin (mTOR) is a kinase regulating a variety of nutrient transporters. The present experiments explored whether mTOR regulates the activity of SLC34A2. In Xenopus oocytes expressing SLC34A2 but not in water injected oocytes phosphate (1 mM) induced a current (Ip) which was significantly enhanced by coexpression of mTOR. Preincubation of the oocytes for 24 h with rapamycin (50 nM) did not significantly affect Ip in the absence of mTOR but virtually abolished the increase of Ip following coexpression of mTOR. The wild type serum and glucocorticoid inducible kinase SGK1 and the constitutively active (S422D)SGK1 similarly stimulated Ip, an effect again reversed by rapamycin. Coexpression of the inactive mutant of the serum and glucocorticoid inducible kinase (K119N)SGK1 significantly decreased Ip and abrogated the stimulating effect of mTOR on Ip. In conclusion, mTOR and SGK1 cooperate in the stimulation of the intestinal phosphate transporter SLC34A2. PMID:16730658

  5. Kinome RNAi Screens Reveal Synergistic Targeting of MTOR and FGFR1 Pathways for Treatment of Lung Cancer and HNSCC.

    PubMed

    Singleton, Katherine R; Hinz, Trista K; Kleczko, Emily K; Marek, Lindsay A; Kwak, Jeff; Harp, Taylor; Kim, Jihye; Tan, Aik Choon; Heasley, Lynn E

    2015-10-15

    The FGFR1 is a therapeutic target under investigation in multiple solid tumors and clinical trials of selective tyrosine kinase inhibitors (TKI) are underway. Treatment with a single TKI represents a logical step toward personalized cancer therapy, but intrinsic and acquired resistance mechanisms limit their long-term benefit. In this study, we deployed RNAi-based functional genomic screens to identify protein kinases controlling the intrinsic sensitivity of FGFR1-dependent lung cancer and head and neck squamous cell cancer (HNSCC) cells to ponatinib, a multikinase FGFR-active inhibitor. We identified and validated a synthetic lethal interaction between MTOR and ponatinib in non-small cell lung carcinoma cells. In addition, treatment with MTOR-targeting shRNAs and pharmacologic inhibitors revealed that MTOR is an essential protein kinase in other FGFR1-expressing cancer cells. The combination of FGFR inhibitors and MTOR or AKT inhibitors resulted in synergistic growth suppression in vitro. Notably, tumor xenografts generated from FGFR1-dependent lung cancer cells exhibited only modest sensitivity to monotherapy with the FGFR-specific TKI, AZD4547, but when combined with the MTOR inhibitor, AZD2014, significantly attenuated tumor growth and prolonged survival. Our findings support the existence of a signaling network wherein FGFR1-driven ERK and activated MTOR/AKT represent distinct arms required to induce full transformation. Furthermore, they suggest that clinical efficacy of treatments for FGFR1-driven lung cancers and HNSCC may be achieved by combining MTOR inhibitors and FGFR-specific TKIs. PMID:26359452

  6. Clinical Impact of Dual Antiplatelet Therapy Use in Patients Following Everolimus-eluting Stent Implantation: Insights from the SEEDS Study

    PubMed Central

    Zhang, Yao-Jun; Zhao, Ye-Lin; Xu, Bo; Han, Ya-Ling; Li, Bao; Liu, Qiang; Su, Xi; Pang, Si; Lu, Shu-Zheng; Guo, Xiao-Feng; Yang, Yue-Jin

    2015-01-01

    Background: Studies have suggested that use of prolonged dual antiplatelet therapy (DAPT) following new generation drug-eluting stent implantation may increase costs and potential bleeding events. This study aimed to investigate the association of DAPT status with clinical safety in patients undergoing everolimus-eluting stent (EES) implantation in the SEEDS study (A Registry to Evaluate Safety and Effectiveness of Everolimus Drug-eluting Stent for Coronary Revascularization) at 2-year follow-up. Methods: The SEEDS study is a prospective, multicenter study, where patients (n = 1900) with small vessel, long lesion, or multi-vessel diseases underwent EES implantation. Detailed DAPT status was collected at baseline, 6-month, 1- and 2-year. DAPT interruption was defined as any interruption of aspirin and/or clopidogrel more than 14 days. The net adverse clinical events (NACE, a composite endpoint of all-cause death, all myocardial infarction (MI), stroke, definite/probable stent thrombosis (ST), and major bleeding (Bleeding Academic Research Consortium II-V)) were investigated according to the DAPT status at 2-year follow-up. Results: DAPT was used in 97.8% of patients at 6 months, 69.5% at 12 months and 35.4% at 2 years. It was observed that the incidence of NACE was low (8.1%) at 2 years follow-up, especially its components of all-cause death (0.9%), stroke (1.1%), and definite/probable ST (0.7%). DAPT was not an independent predictor of composite endpoint of all-cause death/MI/stroke (hazard ratio [HR]: 0.693, 95% confidence interval [CI]: 0.096–4.980, P = 0.715) and NACE (HR: 1.041, 95% CI: 0.145–7.454, P = 0.968). Of 73 patients who had DAPT interruption, no patient had ST at 12-month, and only 1 patient experienced ST between 1- and 2-year (1.4%). There was a high frequency of major bleeding events (53/65, 82.5%) occurred in patients receiving DAPT treatment. Conclusions: Prolonged DAPT use was not associated with improved clinical safety. The study

  7. Randomized comparison of acute stent malapposition between platinum-chromium versus cobalt-chromium everolimus-eluting stents.

    PubMed

    Kim, Byeong-Keuk; Shin, Dong-Ho; Kim, Jung-Sun; Ko, Young-Guk; Choi, Donghoon; Jang, Yangsoo; Hong, Myeong-Ki

    2015-02-01

    No randomized data exist regarding optical coherence tomography (OCT) evaluation immediately post-procedure and at the 3-month follow-up for platinum-chromium everolimus-eluting stents (PtCr-EES) versus cobalt-chromium everolimus-eluting stents (CoCr-EES). A total of 100 patients were randomly assigned to undergo PtCr-EES (n = 51) or CoCr-EES (n = 49) implantation. OCT was serially evaluated after stent deployment with nominal pressure and immediately post-procedure, and 3-month follow-up. The primary endpoint was the percentage of malapposed strut after nominal pressure and immediately post-procedure. Compared to the CoCr-EES, the PtCr-EES showed a lower tendency of percent malapposed strut at nominal pressure [median value (interquartile range); 4.1 % (0.5-11.7) vs. 7.6 % (2.9-13.7), p = 0.082] and immediately post-procedure [1.2 % (0-3.4) vs. 2.5 % (0.7-5.3), p = 0.051]. The percentage of cross sections with any malapposed struts was significantly lower with PtCr-EES at nominal pressure [15.0 % (5.6-39.0) vs. 23.8 % (18.2-44.4), p = 0.036] and immediately post-procedure [6.5 % (0-15.3) vs. 10.5 % (7.1-20.0), p = 0.026]. At the 3-month follow-up, both PtCr-EES and CoCr-EES showed comparable percentages of malapposed struts (0 vs. 0 %, respectively, p = 0.332) and uncovered struts (5.3 vs. 4.7 %, respectively, p = 0.829). We found a significant correlation between the immediate post-procedural percentage of malapposed struts versus the percentage of uncovered struts (r = 0.430, p < 0.001) at the 3-month follow-up. Compared to the CoCr-EES, the PtCr-EES shows a lower tendency toward a lower percentage of malapposed struts but no significant difference in strut coverage at the 3-month follow-up. The percentage of malapposed struts immediately post-procedure was correlated with strut coverage at the 3-month follow-up. PMID:25345751

  8. Distinct amino acid-sensing mTOR pathways regulate skeletal myogenesis.

    PubMed

    Yoon, Mee-Sup; Chen, Jie

    2013-12-01

    Signaling through the mammalian target of rapamycin (mTOR) in response to amino acid availability controls many cellular and developmental processes. mTOR is a master regulator of myogenic differentiation, but the pathways mediating amino acid signals in this process are not known. Here we examine the Rag GTPases and the class III phosphoinositide 3-kinase (PI3K) Vps34, two mediators of amino acid signals upstream of mTOR complex 1 (mTORC1) in cell growth regulation, for their potential involvement in myogenesis. We find that, although both Rag and Vps34 mediate amino acid activation of mTORC1 in C2C12 myoblasts, they have opposing functions in myogenic differentiation. Knockdown of RagA/B enhances, whereas overexpression of active RagB/C mutants impairs, differentiation, and this inhibitory function of Rag is mediated by mTORC1 suppression of the IRS1-PI3K-Akt pathway. On the other hand, Vps34 is required for myogenic differentiation. Amino acids activate a Vps34-phospholipase D1 (PLD1) pathway that controls the production of insulin-like growth factor II, an autocrine inducer of differentiation, through the Igf2 muscle enhancer. The product of PLD, phosphatidic acid, activates the enhancer in a rapamycin-sensitive but mTOR kinase-independent manner. Our results uncover amino acid-sensing mechanisms controlling the homeostasis of myogenesis and underline the versatility and context dependence of mTOR signaling. PMID:24068326

  9. Antitumor effect and antiangiogenic potential of the mTOR inhibitor temsirolimus against malignant pleural mesothelioma.

    PubMed

    Moriya, Makio; Yamada, Tadaaki; Tamura, Masaya; Ishikawa, Daisuke; Hoda, Mir Alireza; Matsumoto, Isao; Klepetko, Walter; Oda, Makoto; Yano, Seiji; Watanabe, Go

    2014-03-01

    The mTOR inhibitor temsirolimus has antitumor and antiangiogenic activity against several carcinomas, yet few reports document the efficacy of temsirolimus against malignant pleural mesothelioma (MPM). Therefore, we evaluated the efficacy of temsirolimus and the antiangiogenic effect of temsirolimus in the treatment of MPM. We examined the efficacy of temsirolimus alone and the efficacy of the combination of temsirolimus and cisplatin or pemetrexed against four MPM cell lines using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. The effect of temsirolimus on the production of proangiogenic cytokines by MPM cell lines was examined by enzyme-linked immunosorbent assay (ELISA). Expression of mTOR and proangiogenic cytokines in clinical specimens from MPM patients was determined by immunohistochemistry. Temsirolimus inhibited cell viability and suppressed cell proliferation of all MPM cell lines. Combined treatment with temsirolimus and cisplatin inhibited the viability of all MPM cell lines more effectively than temsirolimus alone. Temsirolimus strongly inhibited the phosphorylation of p70s6k, a downstream molecule of mTOR, in all MPM cell lines and led to an increase in the levels of cleaved caspase-3 in the H226 and Y-meso14 cells. Temsirolimus also inhibited the production of vascular endothelial growth factor (VEGF) and platelet-derived growth factor-AA (PDGF-AA). Phosphorylated mTOR and high expression of VEGF and PDGF were detected in 2 and 3, respectively, out of the 5 MPM specimens. These results suggest that temsirolimus has activity against MPM cells by inhibition of cell proliferation and angiogenesis, and may be beneficial for a subset of MPM patients with high mTOR expression. PMID:24378576

  10. Inhibition of class I histone deacetylases blunts cardiac hypertrophy through TSC2-dependent mTOR repression

    PubMed Central

    Morales, Cyndi R.; Li, Dan L.; Pedrozo, Zully; May, Herman I.; Jiang, Nan; Kyrychenko, Viktoriia; Cho, Geoffrey; Kim, Soo Young; Wang, Zhao V.; Rotter, David; Rothermel, Beverly A.; Schneider, Jay W.; Lavandero, Sergio; Gillette, Thomas G.; Hill, Joseph A.

    2016-01-01

    Altering chromatin structure through histone posttranslational modifications has emerged as a key driver of transcriptional responses in cells. Modulation of these transcriptional responses by pharmacological inhibition of class I histone deacetylases (HDACs), a group of chromatin remodeling enzymes, has been successful in blocking the growth of some cancer cell types. These inhibitors also attenuate the pathogenesis of pathological cardiac remodeling by blunting and even reversing pathological hypertrophy. The mechanistic target of rapamycin (mTOR) is a critical sensor and regulator of cell growth that as part of mTOR complex I (mTORC1) drives changes in protein synthesis and metabolism in both pathological and physiological hypertrophy. Here, we demonstrated through pharmacological and genetic methods that inhibition of class I HDACs suppressed pathological cardiac hypertrophy through inhibition of mTOR activity. Mice genetically silenced for HDAC1 and HDAC2 had a reduced hypertrophic response to TAC and showed reduced mTOR activity. We determined that the abundance of tuberous sclerosis complex 2 (TSC2), an mTOR inhibitor, was increased through a transcriptional mechanism in cardiomyocytes when class I HDACs were inhibited. In neonatal rat cardiomyocytes, loss of TSC2 abolished HDAC-dependent inhibition of mTOR activity, and increased expression of TSC2 was sufficient to reduce hypertrophy in response to phenylephrine. These findings point to mTOR and TSC2-dependent control of mTOR as critical components of the mechanism by which HDAC inhibitors blunt pathological cardiac growth. These results also suggest a strategy to modulate mTOR activity and facilitate the translational exploitation of HDAC inhibitors in heart disease. PMID:27048565

  11. p53 inhibition provides a pivotal protective effect against ischemia-reperfusion injury in vitro via mTOR signaling.

    PubMed

    Li, Xiaomu; Gu, Shixin; Ling, Yan; Shen, Chao; Cao, Xiaoyun; Xie, Rong

    2015-04-24

    Tumor suppressor p53 has recently been reported to have numerous functions independent of tumorigenesis, including neuronal survival during ischemia. The mammalian target of rapamycin (mTOR) signaling pathway plays a central role in the regulation of metabolism, cell growth, development, and cell survival. Our recent work has demonstrated the neuroprotective effects of the mTOR pathway. Considering that p53 is also an important regulator of mTOR, to further clarify the role of p53 and the mTOR signaling pathway in neuronal ischemic-reperfusion injury, we used mouse primary mixed cultured neurons with an oxygen glucose deprivation (OGD) model to mimic an ischemic-reperfusion injury in vitro. A lentiviral system was also used to inhibit or overexpress p53 to determine whether p53 alteration affects OGD and reperfusion injury. Our results show that activated p53 was induced and it suppressed mTOR expression in primary mixed cultured neurons after OGD and reperfusion. Inhibiting p53, using either a chemical inhibitor or lentiviral-mediated shRNA, exhibited neuroprotective effects in primary cultured neurons against OGD and reperfusion injury through the upregulation of mTOR activity. Such protective effects could be reversed by rapamycin, an mTOR inhibitor. Conversely, p53 overexpression tended to exacerbate the detrimental effects of OGD injury by downregulating mTOR activity. These results suggest that p53 inhibition has a pivotal protective effect against an in vitro ischemia-reperfusion injury via mTOR signaling and provides a potential and promising therapeutic target for stroke treatment. PMID:25681550

  12. Inhibition of class I histone deacetylases blunts cardiac hypertrophy through TSC2-dependent mTOR repression.

    PubMed

    Morales, Cyndi R; Li, Dan L; Pedrozo, Zully; May, Herman I; Jiang, Nan; Kyrychenko, Viktoriia; Cho, Geoffrey W; Kim, Soo Young; Wang, Zhao V; Rotter, David; Rothermel, Beverly A; Schneider, Jay W; Lavandero, Sergio; Gillette, Thomas G; Hill, Joseph A

    2016-01-01

    Altering chromatin structure through histone posttranslational modifications has emerged as a key driver of transcriptional responses in cells. Modulation of these transcriptional responses by pharmacological inhibition of class I histone deacetylases (HDACs), a group of chromatin remodeling enzymes, has been successful in blocking the growth of some cancer cell types. These inhibitors also attenuate the pathogenesis of pathological cardiac remodeling by blunting and even reversing pathological hypertrophy. The mechanistic target of rapamycin (mTOR) is a critical sensor and regulator of cell growth that, as part of mTOR complex 1 (mTORC1), drives changes in protein synthesis and metabolism in both pathological and physiological hypertrophy. We demonstrated through pharmacological and genetic methods that inhibition of class I HDACs suppressed pathological cardiac hypertrophy through inhibition of mTOR activity. Mice genetically silenced for HDAC1 and HDAC2 had a reduced hypertrophic response to thoracic aortic constriction (TAC) and showed reduced mTOR activity. We determined that the abundance of tuberous sclerosis complex 2 (TSC2), an mTOR inhibitor, was increased through a transcriptional mechanism in cardiomyocytes when class I HDACs were inhibited. In neonatal rat cardiomyocytes, loss of TSC2 abolished HDAC-dependent inhibition of mTOR activity, and increased expression of TSC2 was sufficient to reduce hypertrophy in response to phenylephrine. These findings point to mTOR and TSC2-dependent control of mTOR as critical components of the mechanism by which HDAC inhibitors blunt pathological cardiac growth. These results also suggest a strategy to modulate mTOR activity and facilitate the translational exploitation of HDAC inhibitors in heart disease. PMID:27048565

  13. Glycerol-3-phosphate acyltransferase-1 upregulation by O-GlcNAcylation of Sp1 protects against hypoxia-induced mouse embryonic stem cell apoptosis via mTOR activation.

    PubMed

    Lee, H J; Ryu, J M; Jung, Y H; Lee, K H; Kim, D I; Han, H J

    2016-01-01

    Oxygen signaling is critical for stem cell regulation, and oxidative stress-induced stem cell apoptosis decreases the efficiency of stem cell therapy. Hypoxia activates O-linked β-N-acetyl glucosaminylation (O-GlcNAcylation) of stem cells, which contributes to regulation of cellular metabolism, as well as cell fate. Our study investigated the role of O-GlcNAcylation via glucosamine in the protection of hypoxia-induced apoptosis of mouse embryonic stem cells (mESCs). Hypoxia increased mESCs apoptosis in a time-dependent manner. Moreover, hypoxia also slightly increased the O-GlcNAc level. Glucosamine treatment further enhanced the O-GlcNAc level and prevented hypoxia-induced mESC apoptosis, which was suppressed by O-GlcNAc transferase inhibitors. In addition, hypoxia regulated several lipid metabolic enzymes, whereas glucosamine increased expression of glycerol-3-phosphate acyltransferase-1 (GPAT1), a lipid metabolic enzyme producing lysophosphatidic acid (LPA). In addition, glucosamine-increased O-GlcNAcylation of Sp1, which subsequently leads to Sp1 nuclear translocation and GPAT1 expression. Silencing of GPAT1 by gpat1 siRNA transfection reduced glucosamine-mediated anti-apoptosis in mESCs and reduced mammalian target of rapamycin (mTOR) phosphorylation. Indeed, LPA prevented mESCs from undergoing hypoxia-induced apoptosis and increased phosphorylation of mTOR and its substrates (S6K1 and 4EBP1). Moreover, mTOR inactivation by rapamycin (mTOR inhibitor) increased pro-apoptotic proteins expressions and mESC apoptosis. Furthermore, transplantation of non-targeting siRNA and glucosamine-treated mESCs increased cell survival and inhibited flap necrosis in mouse skin flap model. Conversely, silencing of GPAT1 expression reversed those glucosamine effects. In conclusion, enhancing O-GlcNAcylation of Sp1 by glucosamine stimulates GPAT1 expression, which leads to inhibition of hypoxia-induced mESC apoptosis via mTOR activation. PMID:27010859

  14. Glycerol-3-phosphate acyltransferase-1 upregulation by O-GlcNAcylation of Sp1 protects against hypoxia-induced mouse embryonic stem cell apoptosis via mTOR activation

    PubMed Central

    Lee, H J; Ryu, J M; Jung, Y H; Lee, K H; Kim, D I; Han, H J

    2016-01-01

    Oxygen signaling is critical for stem cell regulation, and oxidative stress-induced stem cell apoptosis decreases the efficiency of stem cell therapy. Hypoxia activates O-linked β-N-acetyl glucosaminylation (O-GlcNAcylation) of stem cells, which contributes to regulation of cellular metabolism, as well as cell fate. Our study investigated the role of O-GlcNAcylation via glucosamine in the protection of hypoxia-induced apoptosis of mouse embryonic stem cells (mESCs). Hypoxia increased mESCs apoptosis in a time-dependent manner. Moreover, hypoxia also slightly increased the O-GlcNAc level. Glucosamine treatment further enhanced the O-GlcNAc level and prevented hypoxia-induced mESC apoptosis, which was suppressed by O-GlcNAc transferase inhibitors. In addition, hypoxia regulated several lipid metabolic enzymes, whereas glucosamine increased expression of glycerol-3-phosphate acyltransferase-1 (GPAT1), a lipid metabolic enzyme producing lysophosphatidic acid (LPA). In addition, glucosamine-increased O-GlcNAcylation of Sp1, which subsequently leads to Sp1 nuclear translocation and GPAT1 expression. Silencing of GPAT1 by gpat1 siRNA transfection reduced glucosamine-mediated anti-apoptosis in mESCs and reduced mammalian target of rapamycin (mTOR) phosphorylation. Indeed, LPA prevented mESCs from undergoing hypoxia-induced apoptosis and increased phosphorylation of mTOR and its substrates (S6K1 and 4EBP1). Moreover, mTOR inactivation by rapamycin (mTOR inhibitor) increased pro-apoptotic proteins expressions and mESC apoptosis. Furthermore, transplantation of non-targeting siRNA and glucosamine-treated mESCs increased cell survival and inhibited flap necrosis in mouse skin flap model. Conversely, silencing of GPAT1 expression reversed those glucosamine effects. In conclusion, enhancing O-GlcNAcylation of Sp1 by glucosamine stimulates GPAT1 expression, which leads to inhibition of hypoxia-induced mESC apoptosis via mTOR activation. PMID:27010859

  15. Impact of Everolimus and Low-Dose Cyclosporin on Cytomegalovirus Replication and Disease in Pediatric Renal Transplantation.

    PubMed

    Höcker, B; Zencke, S; Pape, L; Krupka, K; Köster, L; Fichtner, A; Dello Strologo, L; Guzzo, I; Topaloglu, R; Kranz, B; König, J; Bald, M; Webb, N J A; Noyan, A; Dursun, H; Marks, S; Ozcakar, Z B; Thiel, F; Billing, H; Pohl, M; Fehrenbach, H; Schnitzler, P; Bruckner, T; Ahlenstiel-Grunow, T; Tönshoff, B

    2016-03-01

    In order to investigate the hypothesis that the mammalian target of rapamycin inhibitor everolimus (EVR) shows anticytomegalovirus (CMV) activity in pediatric patients, we analyzed the impact of EVR-based immunosuppressive therapy on CMV replication and disease in a large cohort (n = 301) of pediatric kidney allograft recipients. The EVR cohort (n = 59), who also received low-dose cyclosporin, was compared with a control cohort (n = 242), who was administered standard-dose cyclosporin or tacrolimus and an antimetabolite, mostly mycophenolate mofetil (91.7%). Multivariate analysis revealed an 83% lower risk of CMV replication in the EVR cohort than in the control cohort (p = 0.005). In CMV high-risk (donor+/recipient-) patients (n = 88), the EVR-based regimen was associated with a significantly lower rate of CMV disease (0% vs. 14.3%, p = 0.046) than the standard regimen. In patients who had received chemoprophylaxis with (val-)ganciclovir (n = 63), the CMV-free survival rates at 1 year and 3 years posttransplant (100%) were significantly (p = 0.015) higher in the EVR cohort (n = 15) than in the control cohort (n = 48; 1 year, 75.0%; 3 years, 63.3%). Our data suggest that in pediatric patients at high risk of CMV, an EVR-based immunosuppressive regimen is associated with a lower risk of CMV disease than a standard-dose calcineurin inhibitor-based regimen. PMID:26613840

  16. Feasibility of 320-row multi-detector computed tomography angiography to assess bioabsorbable everolimus-eluting vascular scaffolds.

    PubMed

    Asami, Masahiko; Aoki, Jiro; Serruys, Patrick W; Abizaid, Alexandre; Saito, Shigeru; Onuma, Yoshinobu; Kimura, Takeshi; Simonton, Charles A; Tanabe, Kengo

    2016-04-01

    Coronary computer tomographic angiography (CCTA) for screening intra-arterial vessel disease is gaining rapid clinical acceptance in recent years, but its use for such assessments in metal-stented vessel segments is very limited due to blooming artifacts introduced by the metal. However, vessel segments treated by the polymeric everolimus-eluting bioresorbable vascular scaffolds (Absorb) are readily monitored for intravascular disease over time with CCTA. The data on the accuracy of multi-detector computed tomography (MDCT) in patients treated with Absorb is still sparse. Results on 5 Japanese case studies from ABSORB EXTEND are presented here. Five patients were treated with Absorb, and follow-up angiography was conducted at 8 to 14 months as per routine site standard of practice. 320-row MDCT scan was performed within 1 month before the angiography. By MDCT, all Absorb-treated lesions were clearly evaluated and restenosis were not observed. Minimal diameter and % diameter stenosis were similar between MDCT and quantitative angiography (2.07 ± 0.13 vs. 2.03 ± 0.06 mm, P = 0.86, and 22.5 ± 5.0 vs. 21.5 ± 4.5 %, P = 0.88, respectively). MDCT appears to be feasible and useful for evaluating lumen patency and vessel disease in segments implanted with Absorb at follow-up. PMID:26445951

  17. MTOR regulates the pro-tumorigenic senescence-associated secretory phenotype by promoting IL1A translation.

    PubMed

    Laberge, Remi-Martin; Sun, Yu; Orjalo, Arturo V; Patil, Christopher K; Freund, Adam; Zhou, Lili; Curran, Samuel C; Davalos, Albert R; Wilson-Edell, Kathleen A; Liu, Su; Limbad, Chandani; Demaria, Marco; Li, Patrick; Hubbard, Gene B; Ikeno, Yuji; Javors, Martin; Desprez, Pierre-Yves; Benz, Christopher C; Kapahi, Pankaj; Nelson, Peter S; Campisi, Judith

    2015-08-01

    The TOR (target of rapamycin) kinase limits longevity by poorly understood mechanisms. Rapamycin suppresses the mammalian TORC1 complex, which regulates translation, and extends lifespan in diverse species, including mice. We show that rapamycin selectively blunts the pro-inflammatory phenotype of senescent cells. Cellular senescence suppresses cancer by preventing cell proliferation. However, as senescent cells accumulate with age, the senescence-associated secretory phenotype (SASP) can disrupt tissues and contribute to age-related pathologies, including cancer. MTOR inhibition suppressed the secretion of inflammatory cytokines by senescent cells. Rapamycin reduced IL6 and other cytokine mRNA levels, but selectively suppressed translation of the membrane-bound cytokine IL1A. Reduced IL1A diminished NF-κB transcriptional activity, which controls much of the SASP; exogenous IL1A restored IL6 secretion to rapamycin-treated cells. Importantly, rapamycin suppressed the ability of senescent fibroblasts to stimulate prostate tumour growth in mice. Thus, rapamycin might ameliorate age-related pathologies, including late-life cancer, by suppressing senescence-associated inflammation. PMID:26147250

  18. MTOR regulates the pro-tumorigenic senescence-associated secretory phenotype by promoting IL1A translation

    PubMed Central

    Laberge, Remi-Martin; Sun, Yu; Orjalo, Arturo V.; Patil, Christopher K.; Freund, Adam; Zhou, Lili; Curran, Samuel C.; Davalos, Albert R.; Wilson-Edell, Kathleen A.; Liu, Su; Limbad, Chandani; Demaria, Marco; Li, Patrick; Hubbard, Gene B.; Ikeno, Yuji; Javors, Martin; Desprez, Pierre-Yves; Benz, Christopher C.; Kapahi, Pankaj; Nelson, Peter S.; Campisi, Judith

    2015-01-01

    The TOR (target of rapamycin) kinase limits longevity by poorly understood mechanisms. Rapamycin suppresses the mammalian TORC1 complex, which regulates translation, and extends lifespan in diverse species, including mice. We show that rapamycin selectively blunts the pro-inflammatory phenotype of senescent cells. Cellular senescence suppresses cancer by preventing cell proliferation. However, as senescent cells accumulate with age, the senescence-associated secretory phenotype (SASP) can disrupt tissues and contribute to age-related pathologies, including cancer. MTOR inhibition suppressed the secretion of inflammatory cytokines by senescent cells. Rapamycin reduced IL6 and other cytokine mRNA levels, but selectively suppressed translation of the membrane-bound cytokine IL1A. Reduced IL1A diminished NF-κB transcriptional activity, which controls much of the SASP; exogenous IL1A restored IL6 secretion to rapamycin-treated cells. Importantly, rapamycin suppressed the ability of senescent fibroblasts to stimulate prostate tumour growth in mice. Thus, rapamycin might ameliorate age-related pathologies, including late-life cancer, by suppressing senescence-associated inflammation. PMID:26147250

  19. Hypothalamic roles of mTOR complex I: integration of nutrient and hormone signals to regulate energy homeostasis.

    PubMed

    Hu, Fang; Xu, Yong; Liu, Feng

    2016-06-01

    Mammalian or mechanistic target of rapamycin (mTOR) senses nutrient, energy, and hormone signals to regulate metabolism and energy homeostasis. mTOR activity in the hypothalamus, which is associated with changes in energy status, plays a critical role in the regulation of food intake and body weight. mTOR integrates signals from a variety of "energy balancing" hormones such as leptin, insulin, and ghrelin, although its action varies in response to these distinct hormonal stimuli as well as across different neuronal populations. In this review, we summarize and highlight recent findings regarding the functional roles of mTOR complex 1 (mTORC1) in the hypothalamus specifically in its regulation of body weight, energy expenditure, and glucose/lipid homeostasis. Understanding the role and underlying mechanisms behind mTOR-related signaling in the brain will undoubtedly pave new avenues for future therapeutics and interventions that can combat obesity, insulin resistance, and diabetes. PMID:27166282

  20. mTOR inhibition activates overall protein degradation by the ubiquitin proteasome system as well as by autophagy

    PubMed Central

    Zhao, Jinghui; Zhai, Bo; Gygi, Steven P.; Goldberg, Alfred Lewis

    2015-01-01

    Growth factors and nutrients enhance protein synthesis and suppress overall protein degradation by activating the protein kinase mammalian target of rapamycin (mTOR). Conversely, nutrient or serum deprivation inhibits mTOR and stimulates protein breakdown by inducing autophagy, which provides the starved cells with amino acids for protein synthesis and energy production. However, it is unclear whether proteolysis by the ubiquitin proteasome system (UPS), which catalyzes most protein degradation in mammalian cells, also increases when mTOR activity decreases. Here we show that inhibiting mTOR with rapamycin or Torin1 rapidly increases the degradation of long-lived cell proteins, but not short-lived ones, by stimulating proteolysis by proteasomes, in addition to autophagy. This enhanced proteasomal degradation required protein ubiquitination, and within 30 min after mTOR inhibition, the cellular content of K48-linked ubiquitinated proteins increased without any change in proteasome content or activity. This rapid increase in UPS-mediated proteolysis continued for many hours and resulted primarily from inhibition of mTORC1 (not mTORC2), but did not require new protein synthesis or key mTOR targets: S6Ks, 4E-BPs, or Ulks. These findings do not support the recent report that mTORC1 inhibition reduces proteolysis by suppressing proteasome expression [Zhang Y, et al. (2014) Nature 513(7518):440–443]. Several growth-related proteins were identified that were ubiquitinated and degraded more rapidly after mTOR inhibition, including HMG-CoA synthase, whose enhanced degradation probably limits cholesterol biosynthesis upon insulin deficiency. Thus, mTOR inhibition coordinately activates the UPS and autophagy, which provide essential amino acids and, together with the enhanced ubiquitination of anabolic proteins, help slow growth. PMID:26669439

  1. Mammalian Target of Rapamycin (mTOR) Activity Dependent Phospho-Protein Expression in Childhood Acute Lymphoblastic Leukemia (ALL)

    PubMed Central

    Márk, Ágnes; Hajdu, Melinda; Kenessey, István; Sticz, Tamás; Nagy, Eszter; Barna, Gábor; Váradi, Zsófia; Kovács, Gábor; Kopper, László; Csóka, Monika

    2013-01-01

    Modern treatment strategies have improved the prognosis of childhood ALL; however, treatment still fails in 25–30% of patients. Further improvement of treatment may depend on the development of targeted therapies. mTOR kinase, a central mediator of several signaling pathways, has recently attracted remarkable attention as a potential target in pediatric ALL. However, limited data exists about the activity of mTOR. In the present study, the amount of mTOR activity dependent phospho-proteins was characterized by ELISA in human leukemia cell lines and in lymphoblasts from childhood ALL patients (n = 49). Expression was measured before and during chemotherapy and at relapses. Leukemia cell lines exhibited increased mTOR activity, indicated by phospho-S6 ribosomal protein (p-S6) and phosphorylated eukaryotic initiation factor 4E binding protein (p-4EBP1). Elevated p-4EBP1 protein levels were detected in ALL samples at diagnosis; efficacy of chemotherapy was followed by the decrease of mTOR activity dependent protein phosphorylation. Optical density (OD) for p-4EBP1 (ELISA) was significantly higher in patients with poor prognosis at diagnosis, and in the samples of relapsed patients. Our results suggest that measuring mTOR activity related phospho-proteins such as p-4EBP1 by ELISA may help to identify patients with poor prognosis before treatment, and to detect early relapses. Determining mTOR activity in leukemic cells may also be a useful tool for selecting patients who may benefit from future mTOR inhibitor treatments. PMID:23573198

  2. Microfilariae of Brugia malayi Inhibit the mTOR Pathway and Induce Autophagy in Human Dendritic Cells.

    PubMed

    Narasimhan, Prakash Babu; Bennuru, Sasisekhar; Meng, Zhaojing; Cotton, Rachel N; Elliott, Kathleen R; Ganesan, Sundar; McDonald-Fleming, Renee; Veenstra, Timothy D; Nutman, Thomas B; Tolouei Semnani, Roshanak

    2016-09-01

    Immune modulation is a hallmark of patent filarial infection, including suppression of antigen-presenting cell function and downmodulation of filarial antigen-specific T cell responses. The mammalian target of rapamycin (mTOR) signaling pathway has been implicated in immune regulation, not only by suppressing T cell responses but also by regulating autophagy (through mTOR sensing amino acid availability). Global proteomic analysis (liquid chromatography-tandem mass spectrometry) of microfilaria (mf)-exposed monocyte-derived dendritic cells (DC) indicated that multiple components of the mTOR signaling pathway, including mTOR, eIF4A, and eIF4E, are downregulated by mf, suggesting that mf target this pathway for immune modulation in DC. Utilizing Western blot analysis, we demonstrate that similar to rapamycin (a known mTOR inhibitor), mf downregulate the phosphorylation of mTOR and its regulatory proteins, p70S6K1 and 4E-BP1, a process essential for DC protein synthesis. As active mTOR signaling regulates autophagy, we examined whether mf exposure alters autophagy-associated processes. mf-induced autophagy was reflected in marked upregulation of phosphorylated Beclin 1, known to play an important role in both autophagosome formation and autolysosome fusion, in induction of LC3II, a marker of autophagosome formation, and in induced degradation of p62, a ubiquitin-binding protein that aggregates protein in autophagosomes and is degraded upon autophagy that was reduced significantly by mf exposure and by rapamycin. Together, these results suggest that Brugia malayi mf employ mechanisms of metabolic modulation in DC to influence the regulation of the host immune response by downregulating mTOR signaling, resulting in increased autophagy. Whether this is a result of the parasite-secreted rapamycin homolog is currently under study. PMID:27297394

  3. Everolimus for the second-line treatment of advanced and/or metastatic renal cell cancer: a critique of the submission from Novartis.

    PubMed

    Pitt, M; Crathorne, L; Moxham, T; Bond, M; Hyde, C

    2010-10-01

    This paper represents a summary of the evidence review group (ERG) report into the clinical efficacy, safety and cost-effectiveness of everolimus plus best supportive care (BSC) for the treatment of advanced renal cell carcinoma (RCC) which has progressed following or on vascular endothelial growth factor-targeted therapy (sunitinib, sorafenib, bevacizumab), compared to BSC alone. The submitting manufacturer's case for clinical effectiveness and cost-effectiveness was mainly based on a well-conducted randomised controlled trial (RCT), Renal Cell Cancer Treatment with Oral RAD001 Given Daily-1 (RECORD-1), comparing BSC plus everolimus with BSC plus placebo and a de novo economic model. The RCT indicated a marked statistically significant effect on progression-free survival. The base-case incremental cost-effectiveness ratio (ICER) estimate was 52,000 pounds per quality-adjusted life-year (this included a reduction in drug cost associated with an approved patient access scheme). The ERG undertook a critical appraisal of the submission. The ERG was generally in agreement with the submitting manufacturer concerning its estimates of effectiveness; however, there was greater concern surrounding the estimates of cost-effectiveness. The ERG judged that if potential errors in the model were corrected, the ICERs offered by the submitting manufacturer would overstate the cost-effectiveness of everolimus for the second-line treatment of metastatic RCC (that this ICER would be a higher value). Concerning the estimates of cost-effectiveness in RCC, the observations in the ERG report provide strong further support for research collecting rigorous estimates of utilities associated with the main health states likely to be experienced by patients with renal cell cancer. At the time of writing, NICE was yet to issue the Appraisal Consultation Document for this appraisal. PMID:21047490

  4. Nuclear reprogramming of luminal-like breast cancer cells generates Sox2-overexpressing cancer stem-like cellular states harboring transcriptional activation of the mTOR pathway.

    PubMed

    Corominas-Faja, Bruna; Cufí, Sílvia; Oliveras-Ferraros, Cristina; Cuyàs, Elisabet; López-Bonet, Eugeni; Lupu, Ruth; Alarcón, Tomás; Vellon, Luciano; Iglesias, Juan Manuel; Leis, Olatz; Martín, Ángel G; Vazquez-Martin, Alejandro; Menendez, Javier A

    2013-09-15

    . Consistent with the downregulation of AMPK expression, immunoblotting procedures confirmed upregulation of p70S6K and increased phosphorylation of mTOR in Sox2-overexpressing CSC-like cell populations. Using an in vitro model of the de novo generation of CSC-like states through the nuclear reprogramming of an established breast cancer cell line, we reveal that the transcriptional suppression of mTOR repressors is an intrinsic process occurring during the acquisition of CSC-like properties by differentiated populations of luminal-like breast cancer cells. This approach may provide a new path for obtaining information about preventing the appearance of CSCs through the modulation of the AMPK/mTOR pathway. PMID:23974095

  5. CXCR4/CXCL12/CXCR7 axis is functional in neuroendocrine tumors and signals on mTOR

    PubMed Central

    Guadagno, Elia; Tafuto, Salvatore; del Basso de Caro, Marialaura; Botti, Giovanni; Pezzullo, Luciano; Aria, Massimo; Ramundo, Valeria; Tatangelo, Fabiana; Losito, Nunzia Simona; Ieranò, Caterina; D'Alterio, Crescenzo; Izzo, Francesco; Ciliberto, Gennaro; Colao, Annamaria; Faggiano, Antongiulio; Scala, Stefania

    2016-01-01

    Objective To evaluate the possible crosstalk between C-X-C chemokine receptor 4 (CXCR4)/C-X-C motif chemokine 12 (CXCL12)/C-X-C chemokine receptor 7 (CXCR7) axis with the mammalian target of rapamycin (mTOR) pathway in neuroendocrine tumors (NETs). Methods Sixty-one human NETs were included into the study. CXCR4/CXCL12/CXCR7 axis and mTOR pathway were assessed by qRT-PCR and immunohistochemistry (IHC). The effect of mTOR inhibitor, RAD001, was evaluated on CXCR4 pathway through proliferation and p-Erk and p-AKT induction. Results: CXCR4/CXCL12/CXCR7 axis and p-mTOR were found to be active and correlated with grading, Ki67 index and tumor stage. mTOR pathway activation significantly correlated with poor prognosis. In human NET cells, CXCL12 induced mTOR signalling while AMD3100 (CXCR4-antagonist) impaired it. The mTOR-antagonist, RAD001, impaired the CXCL12-dependent induction of CXCR4 downstream effectors. Combination of AMD3100 and RAD001 potentiate cell growth inhibition. Conclusions CXCR4/CXCL12/CXCR7 axis is active in NETs and signals on mTOR. CXCR4 might be considered a prognostic factor in NETs. Combined treatment with AMD3100 and RAD001 may provide clinical benefits in NET patients with drug-resistant. PMID:26934559

  6. mTOR: a link from the extracellular milieu to transcriptional regulation of oligodendrocyte development

    PubMed Central

    Wood, Teresa L.; Bercury, Kathryn K.; Cifelli, Stacey E.; Mursch, Lauren E.; Min, Jungsoo; Dai, Jinxiang; Macklin, Wendy B.

    2013-01-01

    Oligodendrocyte development is controlled by numerous extracellular signals that regulate a series of transcription factors that promote the differentiation of oligodendrocyte progenitor cells to myelinating cells in the central nervous system. A major element of this regulatory system that has only recently been studied is the intracellular signalling from surface receptors to transcription factors to down-regulate inhibitors and up-regulate inducers of oligodendrocyte differentiation and myelination. The current review focuses on one such pathway: the mTOR (mammalian target of rapamycin) pathway, which integrates signals in many cell systems and induces cell responses including cell proliferation and cell differentiation. This review describes the known functions of mTOR as they relate to oligodendrocyte development, and its recently discovered impact on oligodendrocyte differentiation and myelination. A potential model for its role in oligodendrocyte development is proposed. PMID:23421405

  7. Oridonin Suppresses Proliferation of Human Ovarian Cancer Cells via Blockage of mTOR Signaling.

    PubMed

    Xia, Rong; Chen, Sun-Xiao; Qin, Qin; Chen, Yan; Zhang, Wei-Wei; Zhu, Rong-Rong; Deng, An-Mei

    2016-01-01

    Oridonin, an ent-kaurane diterpenoid compound isolated from the traditional Chinese herb Rabdosia rubescens, has shown various pharmacological and physiological effects such as anti-tumor, anti-bacterial, and anti-inflammatory properties. However, the effect of oridonin on human ovarian cancer cell lines has not been determined. In this study, we demonstrated that oridonin inhibited ovarian cancer cell proliferation, migration and invasion in a dose-dependent manner. Furthermore, we showed oridonin inhibited tumor growth of ovarian cancer cells (SKOV3) in vivo. We then assessed mechanisms and found that oridonin specifically abrogated the phosphorylation/activation of mTOR signaling. In summary, our results indicate that oridonin is a potential inhibitor of ovarian cancer by blocking the mTOR signaling pathway. PMID:26925661

  8. Therapeutic potential of targeting mTOR in T-cell acute lymphoblastic leukemia (review).

    PubMed

    Evangelisti, Camilla; Evangelisti, Cecilia; Chiarini, Francesca; Lonetti, Annalisa; Buontempo, Francesca; Bressanin, Daniela; Cappellini, Alessandra; Orsini, Ester; McCubrey, James A; Martelli, Alberto M

    2014-09-01

    T-cell acute lymphoblastic leukemia (T-ALL) is a heterogeneous neoplastic disorder of immature hematopoietic precursors committed to the T-cell lineage. T-ALL comprises about 15% of pediatric and 25% of adult ALL cases. Even if the prognosis of T-ALL has improved especially in the childhood due to the use of new intensified treatment protocols, the outcome of relapsed patients who are resistant to conventional chemotherapeutic drugs or who relapse is still poor. For this reason, there is a need for novel and less toxic targeted therapies against signaling pathways aberrantly activated in T-ALL, such as the phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR). Small molecules designed to target key components of this signaling axis have proven their efficacy both in vitro and in vivo in pre-clinical settings of T-ALL. In particular, different classes of mTOR inhibitors have been disclosed by pharmaceutical companies, and they are currently being tested in clinical trials for treating T-ALL patients. One of the most promising approaches for the treatment of T-ALL seems to be the combination of mTOR inhibitors with traditional chemotherapeutic agents. This could lead to a lower drug dosage that may circumvent the systemic side effects of chemotherapeutics. In this review, we focus on the different classes of mTOR inhibitors that will possibly have an impact on the therapeutic arsenal we have at our disposal against T-ALL. PMID:24968804

  9. Azithromycin suppresses CD4+ T-cell activation by direct modulation of mTOR activity

    PubMed Central

    Ratzinger, F.; Haslacher, H.; Poeppl, W.; Hoermann, G.; Kovarik, J. J.; Jutz, S.; Steinberger, P.; Burgmann, H.; Pickl, W. F.; Schmetterer, K. G.

    2014-01-01

    Advanced macrolides, such as azithromycin (AZM) or clarithromycin (CLM), are antibiotics with immunomodulatory properties. Here we have sought to evaluate their in vitro influence on the activation of CD4+ T-cells. Isolated CD4+ T-cells were stimulated with agonistic anti-CD3/anti-CD28 monoclonal antibodies in the presence of 0.6 mg/L, 2.5 mg/L, 10 mg/L or 40 mg/L AZM or CLM. Cell proliferation, cytokine level in supernatants and cell viability was assessed. Intracellular signaling pathways were evaluated using reporter cell lines, FACS analysis, immunoblotting and in vitro kinase assays. AZM inhibited cell proliferation rate and cytokine secretion of CD4+ T-cells in a dose-dependent manner. Similarly, high concentrations of CLM (40 mg/L) also suppressed these T-cell functions. Analysis of molecular signaling pathways revealed that exposure to AZM reduced the phosphorylation of the S6 ribosomal protein, a downstream target of mTOR. This effect was also observed at 40 mg/L CLM. In vitro kinase studies using recombinant mTOR showed that AZM inhibited mTOR activity. In contrast to rapamycin, this inhibition was independent of FKBP12. We show for the first time that AZM and to a lesser extent CLM act as immunosuppressive agents on CD4+ T-cells by inhibiting mTOR activity. Our results might have implications for the clinical use of macrolides. PMID:25500904

  10. Regulation of mTOR activity in Snell dwarf and GH receptor gene-disrupted mice.

    PubMed

    Dominick, Graham; Berryman, Darlene E; List, Edward O; Kopchick, John J; Li, Xinna; Miller, Richard A; Garcia, Gonzalo G

    2015-02-01

    The involvement of mammalian target of rapamycin (mTOR) in lifespan control in invertebrates, calorie-restricted rodents, and extension of mouse lifespan by rapamycin have prompted speculation that diminished mTOR function may contribute to mammalian longevity in several settings. We show here that mTOR complex-1 (mTORC1) activity is indeed lower in liver, muscle, heart, and kidney tissue of Snell dwarf and global GH receptor (GHR) gene-disrupted mice (GHR-/-), consistent with previous studies. Surprisingly, activity of mTORC2 is higher in fasted Snell and GHR-/- than in littermate controls in all 4 tissues tested. Resupply of food enhanced mTORC1 activity in both controls and long-lived mutant mice but diminished mTORC2 activity only in the long-lived mice. Mice in which GHR has been disrupted only in the liver do not show extended lifespan and also fail to show the decline in mTORC1 and increase in mTORC2 seen in mice with global loss of GHR. The data suggest that the antiaging effects in the Snell dwarf and GHR-/- mice are accompanied by both a decline in mTORC1 in multiple organs and an increase in fasting levels of mTORC2. Neither the lifespan nor mTOR effects appear to be mediated by direct GH effects on liver or by the decline in plasma IGF-I, a shared trait in both global and liver-specific GHR-/- mice. Our data suggest that a more complex pattern of hormonal effects and intertissue interactions may be responsible for regulating both lifespan and mTORC2 function in these mouse models of delayed aging. PMID:25456069

  11. mTOR Signaling Regulates Nucleolar Targeting of the SUMO-Specific Isopeptidase SENP3

    PubMed Central

    Raman, Nithya; Nayak, Arnab

    2014-01-01

    Ribosome biogenesis is a multistep cellular pathway that involves more than 200 regulatory components to ultimately generate translation-competent 80S ribosomes. The initial steps of this process, particularly rRNA processing, take place in the nucleolus, while later stages occur in the nucleoplasm and cytoplasm. One critical factor of 28S rRNA maturation is the SUMO-isopeptidase SENP3. SENP3 tightly interacts with the nucleolar scaffold protein NPM1 and is associated with nucleolar 60S preribosomes. A central question is how changes in energy supply feed into the regulation of ribosome maturation. Here, we show that the nutrient-sensing mTOR kinase pathway controls the nucleolar targeting of SENP3 by regulating its interaction with NPM1. We define an N-terminal domain in SENP3 as the critical NPM1 binding region and provide evidence that mTOR-mediated phosphorylation of serine/threonine residues within this region fosters the interaction of SENP3 with NPM1. The inhibition of mTOR triggers the nucleolar release of SENP3, thereby likely compromising its activity in rRNA processing. Since mTOR activity is tightly coupled to nutrient availability, we propose that this pathway contributes to the adaptation of ribosome maturation in response to the cellular energy status. PMID:25288641

  12. A liaison between mTOR signaling, ribosome biogenesis and cancer☆

    PubMed Central

    Gentilella, Antonio; Kozma, Sara C.; Thomas, George

    2016-01-01

    The ability to translate genetic information into functional proteins is considered a landmark in evolution. Ribosomes have evolved to take on this responsibility and, although there are some differences in their molecular make-up, both prokaryotes and eukaryotes share a common structural architecture and similar underlying mechanisms of protein synthesis. Understanding ribosome function and biogenesis has been the focus of extensive research since the early days of their discovery. In the last decade however, new and unexpected roles have emerged that place deregulated ribosome biogenesis and protein synthesis at the crossroads of pathological settings, particularly cancer, revealing a set of novel cellular checkpoints. Moreover, it is also becoming evident that mTOR signaling, which regulates an array of anabolic processes, including ribosome biogenesis, is often exploited by cancer cells to sustain proliferation through the upregulation of global protein synthesis. The use of pharmacological agents that interfere with ribosome biogenesis and mTOR signaling has proven to be an effective strategy to control cancer development clinically. Here we discuss the most recent findings concerning the underlying mechanisms by which mTOR signaling controls ribosome production and the potential impact of ribosome bio-genesis in tumor development. This article is part of a Special Issue entitled: Translation and Cancer. PMID:25735853

  13. Repression of protein translation and mTOR signaling by proteasome inhibitor in colon cancer cells

    SciTech Connect

    Wu, William Ka Kei; Volta, Viviana; Cho, Chi Hin; Wu, Ya Chun; Li, Hai Tao; Yu, Le; Li, Zhi Jie; Sung, Joseph Jao Yiu

    2009-09-04

    Protein homeostasis relies on a balance between protein synthesis and protein degradation. The ubiquitin-proteasome system is a major catabolic pathway for protein degradation. In this respect, proteasome inhibition has been used therapeutically for the treatment of cancer. Whether inhibition of protein degradation by proteasome inhibitor can repress protein translation via a negative feedback mechanism, however, is unknown. In this study, proteasome inhibitor MG-132 lowered the proliferation of colon cancer cells HT-29 and SW1116. In this connection, MG-132 reduced the phosphorylation of mammalian target of rapamycin (mTOR) at Ser2448 and Ser2481 and the phosphorylation of its downstream targets 4E-BP1 and p70/p85 S6 kinases. Further analysis revealed that MG-132 inhibited protein translation as evidenced by the reductions of {sup 35}S-methionine incorporation and polysomes/80S ratio. Knockdown of raptor, a structural component of mTOR complex 1, mimicked the anti-proliferative effect of MG-132. To conclude, we demonstrate that the inhibition of protein degradation by proteasome inhibitor represses mTOR signaling and protein translation in colon cancer cells.

  14. SMN regulates axonal local translation via miR-183/mTOR pathway

    PubMed Central

    Kye, Min Jeong; Niederst, Emily D.; Wertz, Mary H.; Gonçalves, Inês do Carmo G.; Akten, Bikem; Dover, Katarzyna Z.; Peters, Miriam; Riessland, Markus; Neveu, Pierre; Wirth, Brunhilde; Kosik, Kenneth S.; Sardi, S. Pablo; Monani, Umrao R.; Passini, Marco A.; Sahin, Mustafa

    2014-01-01

    Reduced expression of SMN protein causes spinal muscular atrophy (SMA), a neurodegenerative disorder leading to motor neuron dysfunction and loss. However, the molecular mechanisms by which SMN regulates neuronal dysfunction are not fully understood. Here, we report that reduced SMN protein level alters miRNA expression and distribution in neurons. In particular, miR-183 levels are increased in neurites of SMN-deficient neurons. We demonstrate that miR-183 regulates translation of mTor via direct binding to its 3′ UTR. Interestingly, local axonal translation of mTor is reduced in SMN-deficient neurons, and this can be recovered by miR-183 inhibition. Finally, inhibition of miR-183 expression in the spinal cord of an SMA mouse model prolongs survival and improves motor function of Smn-mutant mice. Together, these observations suggest that axonal miRNAs and the mTOR pathway are previously unidentified molecular mechanisms contributing to SMA pathology. PMID:25055867

  15. mTOR Mediates IL-23 Induction of Neutrophil IL-17 and IL-22 Production.

    PubMed

    Chen, Feidi; Cao, Anthony; Yao, Suxia; Evans-Marin, Heather L; Liu, Han; Wu, Wei; Carlsen, Eric D; Dann, Sara M; Soong, Lynn; Sun, Jiaren; Zhao, Qihong; Cong, Yingzi

    2016-05-15

    It has been shown recently that neutrophils are able to produce IL-22 and IL-17, which differentially regulate the pathogenesis of inflammatory bowel disease. However, it is still largely unknown how the neutrophil production of IL-22 and IL-17 is regulated, and their role in the pathogenesis of inflammatory bowel disease. In this study, we found that IL-23 promoted neutrophil production of IL-17 and IL-22. IL-23 stimulated the neutrophil expression of IL-23R as well as rorc and ahr. Retinoid acid receptor-related orphan receptor γ t and aryl-hydrocarbon receptor differentially regulated IL-23 induction of neutrophil IL-17 and IL-22. In addition, IL-23 induced the activation of mTOR in neutrophils. Blockade of the mTOR pathway inhibited IL-23-induced expression of rorc and ahr, as well as IL-17 and IL-22 production. By using a microbiota Ag-specific T cell-mediated colitis model, we demonstrated that depletion of neutrophils, as well as blockade of IL-22, resulted in a significant increase in the severity of colitis, thereby indicating a protective role of neutrophils and IL-22 in chronic colitis. Collectively, our data revealed that neutrophils negatively regulate microbiota Ag-specific T cell induction of colitis, and IL-23 induces neutrophil production of IL-22 and IL-17 through induction of rorc and ahr, which is mediated by the mTOR pathway. PMID:27067005

  16. Erythropoietin mediated bone formation is regulated by mTOR signaling.

    PubMed

    Kim, Jinkoo; Jung, Younghun; Sun, Hongli; Joseph, Jeena; Mishra, Anjali; Shiozawa, Yusuke; Wang, Jingcheng; Krebsbach, Paul H; Taichman, Russell S

    2012-01-01

    The role of erythropoietin (Epo) and Epo/Epo receptor (EpoR) signaling pathways for production of red blood cells are well established. However, little is known about Epo/EpoR signaling in non-hematopoietic cells. Recently, we demonstrated that Epo activates JAK/STAT signaling in hematopoietic stem cells (HSCs), leading to the production of bone morphogenetic protein 2 (BMP2) and bone formation and that Epo also directly activates mesenchymal cells to form osteoblasts in vitro. In this study, we investigated the effects of mTOR signaling on Epo-mediated osteoblastogenesis and osteoclastogenesis. We found that mTOR inhibition by rapamycin blocks Epo-dependent and -independent osteoblastic phenotypes in human bone marrow stromal cells (hBMSCs) and ST2 cells, respectively. Furthermore, we found that rapamycin inhibits Epo-dependent and -independent osteoclastogenesis in mouse bone marrow mononuclear cells and Raw264.7 cells. Finally, we demonstrated that Epo increases NFATc1 expression and decreases cathepsin K expression in an mTOR-independent manner, resulting in an increase of osteoclast numbers and a decrease in resorption activity. Taken together, these results strongly indicate that mTOR signaling plays an important role in Epo-mediated bone homeostasis. PMID:21898543

  17. mTOR target NDRG1 confers MGMT-dependent resistance to alkylating chemotherapy

    PubMed Central

    Weiler, Markus; Blaes, Jonas; Pusch, Stefan; Sahm, Felix; Czabanka, Marcus; Luger, Sebastian; Bunse, Lukas; Solecki, Gergely; Eichwald, Viktoria; Jugold, Manfred; Hodecker, Sibylle; Osswald, Matthias; Meisner, Christoph; Hielscher, Thomas; Rübmann, Petra; Pfenning, Philipp-Niklas; Ronellenfitsch, Michael; Kempf, Tore; Schnölzer, Martina; Abdollahi, Amir; Lang, Florian; Bendszus, Martin; von Deimling, Andreas; Winkler, Frank; Weller, Michael; Vajkoczy, Peter; Platten, Michael; Wick, Wolfgang

    2014-01-01

    A hypoxic microenvironment induces resistance to alkylating agents by activating targets in the mammalian target of rapamycin (mTOR) pathway. The molecular mechanisms involved in this mTOR-mediated hypoxia-induced chemoresistance, however, are unclear. Here we identify the mTOR target N-myc downstream regulated gene 1 (NDRG1) as a key determinant of resistance toward alkylating chemotherapy, driven by hypoxia but also by therapeutic measures such as irradiation, corticosteroids, and chronic exposure to alkylating agents via distinct molecular routes involving hypoxia-inducible factor (HIF)-1alpha, p53, and the mTOR complex 2 (mTORC2)/serum glucocorticoid-induced protein kinase 1 (SGK1) pathway. Resistance toward alkylating chemotherapy but not radiotherapy was dependent on NDRG1 expression and activity. In posttreatment tumor tissue of patients with malignant gliomas, NDRG1 was induced and predictive of poor response to alkylating chemotherapy. On a molecular level, NDRG1 bound and stabilized methyltransferases, chiefly O6-methylguanine-DNA methyltransferase (MGMT), a key enzyme for resistance to alkylating agents in glioblastoma patients. In patients with glioblastoma, MGMT promoter methylation in tumor tissue was not more predictive for response to alkylating chemotherapy in patients who received concomitant corticosteroids. PMID:24367102

  18. IL-12 is required for mTOR regulation of memory CTLs during viral infection

    PubMed Central

    Garcia, Karla; Sun, Zhifeng; Mattson, Elliot; Li, Lei; Smyth, Kendra; Xiao, Zhengguo

    2014-01-01

    The induction of functional memory CTLs is a major goal of vaccination against intracellular pathogens. IL-12 is critical for the generation of memory CTLs, and inhibition of mTOR by rapamycin can effectively enhance the memory CTL response. Yet, the role of IL-12 in mTOR’s regulation of memory CTL is unknown. Here, we hypothesized that the immunostimulatory effects of mTOR on memory CTLs requires IL-12 signaling. Our results revealed that rapamycin increased the generation of memory CTLs in vaccinia virus infection, and this enhancement was dependent upon the IL-12 signal. Furthermore, IL-12 receptor deficiency diminished the secondary expansion of rapamycin-regulated memory, and resultant secondary memory CTLs were abolished. Rapamycin enhanced IL-12 signaling by up regulating IL-12 receptor β2 expression and STAT4 phosphorylation in CTLs during early infection. In addition, rapamycin continually suppressed T-bet expression in both WT and IL-12 receptor knockout CTLs. These results indicate an essential role for IL-12 in the regulation of memory CTLs by mTOR, and highlight the importance of considering the interplay between cytokines and adjuvants during vaccine design. PMID:24898389

  19. Prevention of irradiation-induced salivary hypofunction by rapamycin in swine parotid glands.

    PubMed

    Zhu, Zhao; Pang, Baoxing; Iglesias-Bartolome, Ramiro; Wu, Xiaoshan; Hu, Lei; Zhang, Chunmei; Wang, Jinsong; Gutkind, J Silvio; Wang, Songlin

    2016-04-12

    Radiotherapy is commonly used in patients with oral cavity and pharyngeal cancers, usually resulting in irreversible salivary hypofunction. Currently management of radiation damage to salivary glands still remains a great challenge. Recent studies show that activation of mammalian target of rapamycin (mTOR) occurs in salivary gland lesions, making it possible to apply mTOR inhibitor for treatment. Our results indicate inhibition of mTOR by rapamycin significantly alleviated irradiation-induced salivary hypofunction by restoring 46% salivary flow rate and protecting histological structures in swine. Furthermore, rapamycin protected human submandibular gland cell line (HSG) from irradiation-induced cell depletion and loss of cell proliferation capacity. These findings lay the foundation for a new clinical application of rapamycin to prevent irradiation-induced salivary hypofunction. PMID:26958808

  20. Prevention of irradiation-induced salivary hypofunction by rapamycin in swine parotid glands

    PubMed Central

    Zhu, Zhao; Pang, Baoxing; Iglesias-Bartolome, Ramiro; Wu, Xiaoshan; Hu, Lei; Zhang, Chunmei; Wang, Jinsong; Silvio Gutkind, J; Wang, Songlin

    2016-01-01

    Radiotherapy is commonly used in patients with oral cavity and pharyngeal cancers, usually resulting in irreversible salivary hypofunction. Currently management of radiation damage to salivary glands still remains a great challenge. Recent studies show that activation of mammalian target of rapamycin (mTOR) occurs in salivary gland lesions, making it possible to apply mTOR inhibitor for treatment. Our results indicate inhibition of mTOR by rapamycin significantly alleviated irradiation-induced salivary hypofunction by restoring 46% salivary flow rate and protecting histological structures in swine. Furthermore, rapamycin protected human submandibular gland cell line (HSG) from irradiation-induced cell depletion and loss of cell proliferation capacity. These findings lay the foundation for a new clinical application of rapamycin to prevent irradiation-induced salivary hypofunction. PMID:26958808

  1. Improved oral absorption and chemical stability of everolimus via preparation of solid dispersion using solvent wetting technique.

    PubMed

    Jang, Sun Woo; Kang, Myung Joo

    2014-10-01

    The aim of this study was to improve the physicochemical properties and oral absorption of poorly water-soluble everolimus via preparation of a solid dispersion (SD) system using a solvent wetting (SW) technique. The physicochemical properties, drug release profile, and bioavailability of SD prepared by SW process were also compared to SD prepared by the conventional co-precipitation method. Solid state characterizations using scanning electron microscopy, particle size analysis and X-ray powder diffraction indicated that drug homogeneously dispersed and existed in an amorphous state within the intact polymeric carrier. Whereas, a film-like mass was obtained by a co-precipitation method and further pulverization step was needed for tabletization. The drug release from the SD tablet prepared by SW process at a ratio of drug to hydroxypropyl methylcellulose of 1:15 was markedly higher than the drug alone and equivalent to the marketed product (Afinitor(®), Novartis Pharmaceuticals), a SD tablet prepared by co-precipitation method, archiving over 75% the drug release after 30 min. At the accelerated (40°C/75% R.H.) and stress (80°C) stability tests, the novel formula was more stable than drug powder and provided comparable drug stability with the commercially available product, which contains a potentially risky antioxidant, butylated hydroxyl toluene. The pharmacokinetic parameters after single oral administration in beagles showed no significant difference (P>0.01) between the novel SD-based tablet and the marketed product. The results of this study, therefore, suggest that the novel SD system prepared by the solvent wetting process may be a promising approach for improving the physicochemical stability and oral absorption of the sirolimus derivatives. PMID:25003829

  2. FK866-induced NAMPT inhibition activates AMPK and downregulates mTOR signaling in hepatocarcinoma cells

    SciTech Connect

    Schuster, Susanne; Penke, Melanie; Gorski, Theresa; Gebhardt, Rolf; Weiss, Thomas S.; Kiess, Wieland; Garten, Antje

    2015-03-06

    Background: Nicotinamide phosphoribosyltransferase (NAMPT) is the key enzyme of the NAD salvage pathway starting from nicotinamide. Cancer cells have an increased demand for NAD due to their high proliferation and DNA repair rate. Consequently, NAMPT is considered as a putative target for anti-cancer therapies. There is evidence that AMP-activated protein kinase (AMPK) and mammalian target of rapamycin (mTOR) become dysregulated during the development of hepatocellular carcinoma (HCC). Here, we investigated the effects of NAMPT inhibition by its specific inhibitor FK866 on the viability of hepatocarcinoma cells and analyzed the effects of FK866 on the nutrient sensor AMPK and mTOR complex1 (mTORC1) signaling. Results: FK866 markedly decreased NAMPT activity and NAD content in hepatocarcinoma cells (Huh7 cells, Hep3B cells) and led to delayed ATP reduction which was associated with increased cell death. These effects could be abrogated by administration of nicotinamide mononucleotide (NMN), the enzyme product of NAMPT. Our results demonstrated a dysregulation of the AMPK/mTOR pathway in hepatocarcinoma cells compared to non-cancerous hepatocytes with a higher expression of mTOR and a lower AMPKα activation in hepatocarcinoma cells. We found that NAMPT inhibition by FK866 significantly activated AMPKα and inhibited the activation of mTOR and its downstream targets p70S6 kinase and 4E-BP1 in hepatocarcinoma cells. Non-cancerous hepatocytes were less sensitive to FK866 and did not show changes in AMPK/mTOR signaling after FK866 treatment. Conclusion: Taken together, these findings reveal an important role of the NAMPT-mediated NAD salvage pathway in the energy homeostasis of hepatocarcinoma cells and suggest NAMPT inhibition as a potential treatment option for HCC. - Highlights: • FK866 increases cell death in p53-deficient hepatocarcinoma cells. • AMPK/mTOR signaling is dysregulated in hepatocarcinoma cells. • FK866-induced NAMPT inhibition activates AMPK

  3. Inhibitory Effect of mTOR Activator MHY1485 on Autophagy: Suppression of Lysosomal Fusion

    PubMed Central

    Choi, Yeon Ja; Park, Yun Jung; Park, Ji Young; Jeong, Hyoung Oh; Kim, Dae Hyun; Ha, Young Mi; Kim, Ji Min; Song, Yu Min; Heo, Hyoung-Sam; Yu, Byung Pal; Chun, Pusoon; Moon, Hyung Ryong; Chung, Hae Young

    2012-01-01

    Autophagy is a major degradative process responsible for the disposal of cytoplasmic proteins and dysfunctional organelles via the lysosomal pathway. During the autophagic process, cells form double-membraned vesicles called autophagosomes that sequester disposable materials in the cytoplasm and finally fuse with lysosomes. In the present study, we investigated the inhibition of autophagy by a synthesized compound, MHY1485, in a culture system by using Ac2F rat hepatocytes. Autophagic flux was measured to evaluate the autophagic activity. Autophagosomes were visualized in Ac2F cells transfected with AdGFP-LC3 by live-cell confocal microscopy. In addition, activity of mTOR, a major regulatory protein of autophagy, was assessed by western blot and docking simulation using AutoDock 4.2. In the result, treatment with MHY1485 suppressed the basal autophagic flux, and this inhibitory effect was clearly confirmed in cells under starvation, a strong physiological inducer of autophagy. The levels of p62 and beclin-1 did not show significant change after treatment with MHY1485. Decreased co-localization of autophagosomes and lysosomes in confocal microscopic images revealed the inhibitory effect of MHY1485 on lysosomal fusion during starvation-induced autophagy. These effects of MHY1485 led to the accumulation of LC3II and enlargement of the autophagosomes in a dose- and time- dependent manner. Furthermore, MHY1485 induced mTOR activation and correspondingly showed a higher docking score than PP242, a well-known ATP-competitive mTOR inhibitor, in docking simulation. In conclusion, MHY1485 has an inhibitory effect on the autophagic process by inhibition of fusion between autophagosomes and lysosomes leading to the accumulation of LC3II protein and enlarged autophagosomes. MHY1485 also induces mTOR activity, providing a possibility for another regulatory mechanism of autophagy by the MHY compound. The significance of this study is the finding of a novel inhibitor of autophagy

  4. Inhibition of mTOR signaling protects photoreceptor cells against serum deprivation by reducing oxidative stress and inducing G2/M cell cycle arrest

    PubMed Central

    FAN, BIN; LI, FU-QAING; SONG, JING-YAO; CHEN, XU; LI, GUANG-YU

    2016-01-01

    The mammalian target of rapamycin (mTOR) pathway is a crucial cellular signaling hub, which integrates internal and external cues to modulate the cell cycle, protein synthesis and metabolism. The present study hypothesized that inhibiting mTOR signaling may induce cells to enter lower and more stable bioenergetic states, in which neurons have greater resistance to various insults. Neurotrophin withdrawal from photoreceptor cells (661W cells) was mimicked using serum deprivation, and the neuroprotective mechanisms were studied following suppression of the mTOR pathway. Treatment with an mTOR specific inhibitor, rapamycin, reduced intracellular levels of reactive oxygen species, suppressed oxidative stress, and attenuated mitochondrial dysfunction. In addition, inhibiting mTOR signaling induced a G2/M cell cycle arrest, thus providing an opportunity to repair damaged DNA and block the cell death cascade. These results suggested that inhibition of mTOR had a neuroprotective effect on serum-deprived 661W cells. In conclusion, the mTOR pathway is a critical molecular signal for cell cycle regulation and energy metabolism, and inhibiting the mTOR pathway may attenuate neurotrophin withdrawal-induced damage. These observations may provide evidence for the treatment of retinal degenerative disease, since inducing neurons into a lower and more stable bioenergetic state by blocking mTOR signaling may slow the progression of neurodegenerative diseases. PMID:27035647

  5. BIM and mTOR expression levels predict outcome to erlotinib in EGFR-mutant non-small-cell lung cancer

    PubMed Central

    Karachaliou, Niki; Codony-Servat, Jordi; Teixidó, Cristina; Pilotto, Sara; Drozdowskyj, Ana; Codony-Servat, Carles; Giménez-Capitán, Ana; Molina-Vila, Miguel Angel; Bertrán-Alamillo, Jordi; Gervais, Radj; Massuti, Bartomeu; Morán, Teresa; Majem, Margarita; Felip, Enriqueta; Carcereny, Enric; García-Campelo, Rosario; Viteri, Santiago; González-Cao, María; Morales-Espinosa, Daniela; Verlicchi, Alberto; Crisetti, Elisabetta; Chaib, Imane; Santarpia, Mariacarmela; Luis Ramírez, José; Bosch-Barrera, Joaquim; Felipe Cardona, Andrés; de Marinis, Filippo; López-Vivanco, Guillermo; Miguel Sánchez, José; Vergnenegre, Alain; Sánchez Hernández, José Javier; Sperduti, Isabella; Bria, Emilio; Rosell, Rafael

    2015-01-01

    BIM is a proapoptotic protein that initiates apoptosis triggered by EGFR tyrosine kinase inhibitors (TKI). mTOR negatively regulates apoptosis and may influence response to EGFR TKI. We examined mRNA expression of BIM and MTOR in 57 patients with EGFR-mutant NSCLC from the EURTAC trial. Risk of mortality and disease progression was lower in patients with high BIM compared with low/intermediate BIM mRNA levels. Analysis of MTOR further divided patients with high BIM expression into two groups, with those having both high BIM and MTOR experiencing shorter overall and progression-free survival to erlotinib. Validation of our results was performed in an independent cohort of 19 patients with EGFR-mutant NSCLC treated with EGFR TKIs. In EGFR-mutant lung adenocarcinoma cell lines with high BIM expression, concomitant high mTOR expression increased IC50 of gefitinib for cell proliferation. We next sought to analyse the signalling pattern in cell lines with strong activation of mTOR and its substrate P-S6. We showed that mTOR and phosphodiesterase 4D (PDE4D) strongly correlate in resistant EGFR-mutant cancer cell lines. These data suggest that the combination of EGFR TKI with mTOR or PDE4 inhibitors could be adequate therapy for EGFR-mutant NSCLC patients with high pretreatment levels of BIM and mTOR. PMID:26639561

  6. Disruption of the Mouse mTOR Gene Leads to Early Postimplantation Lethality and Prohibits Embryonic Stem Cell Development

    PubMed Central

    Gangloff, Yann-Gaël; Mueller, Matthias; Dann, Stephen G.; Svoboda, Petr; Sticker, Melanie; Spetz, Jean-Francois; Um, Sung Hee; Brown, Eric J.; Cereghini, Silvia; Thomas, George; Kozma, Sara C.

    2004-01-01

    The mammalian target of rapamycin (mTOR) is a key component of a signaling pathway which integrates inputs from nutrients and growth factors to regulate cell growth. Recent studies demonstrated that mice harboring an ethylnitrosourea-induced mutation in the gene encoding mTOR die at embryonic day 12.5 (E12.5). However, others have shown that the treatment of E4.5 blastocysts with rapamycin blocks trophoblast outgrowth, suggesting that the absence of mTOR should lead to embryonic lethality at an earlier stage. To resolve this discrepancy, we set out to disrupt the mTOR gene and analyze the outcome in both heterozygous and homozygous settings. Heterozygous mTOR (mTOR+/−) mice do not display any overt phenotype, although mouse embryonic fibroblasts derived from these mice show a 50% reduction in mTOR protein levels and phosphorylation of S6 kinase 1 T389, a site whose phosphorylation is directly mediated by mTOR. However, S6 phosphorylation, raptor levels, cell size, and cell cycle transit times are not diminished in these cells. In contrast to the situation in mTOR+/− mice, embryonic development of homozygous mTOR−/− mice appears to be arrested at E5.5; such embryos are severely runted and display an aberrant developmental phenotype. The ability of these embryos to implant corresponds to a limited level of trophoblast outgrowth in vitro, reflecting a maternal mRNA contribution, which has been shown to persist during preimplantation development. Moreover, mTOR−/− embryos display a lesion in inner cell mass proliferation, consistent with the inability to establish embryonic stem cells from mTOR−/− embryos. PMID:15485918

  7. PKM2 enhances chemosensitivity to cisplatin through interaction with the mTOR pathway in cervical cancer.

    PubMed

    Zhu, Haiyan; Wu, Jun; Zhang, Wenwen; Luo, Hui; Shen, Zhaojun; Cheng, Huihui; Zhu, Xueqiong

    2016-01-01

    Pyruvate kinase M2 (PKM2) is a key driver of aerobic glycolysis in cancer cells and has been shown to be up-regulated by mTOR in vitro. Our previous proteomic profiling studies showed that PKM2 was significantly upregulated in cervical cancer tissues after treatment with neoadjuvant chemotherapy (NACT). Whether PKM2 expression predicts cisplatin-based NACT sensitivity and is mTOR dependent in cervical cancer patients remains unclear. Using paired tumor samples (pre- and post-chemotherapy) from 36 cervical cancer patients, we examined mTOR, HIF-1α, c-Myc, and PKM2 expression in cervical cancer samples and investigated the response to cisplatin-based NACT. In addition, we established PKM2 suppressed cervical cancer cell lines and evaluated their sensitivity to cisplatin in vitro. We found that the mTOR/HIF-1α/c-Myc/PKM2 signaling pathway was significantly downregulated in post-chemotherapy cervical cancer tissues. High levels of mTOR, HIF-1α, c-Myc, and PKM2 were associated with a positive chemotherapy response in cervical cancer patients treated with cisplatin-based NACT. In vitro, PKM2 knockdown desensitized cervical cancer cells to cisplatin. Moreover, PKM2 had complex interactions with mTOR pathways. mTOR, HIF1α, c-Myc, and PKM2 expression in cervical cancer may serve as predictive biomarkers to cisplatin-based chemotherapy. PKM2 enhances chemosensitivity to cisplatin through interaction with the mTOR pathway in cervical cancer. PMID:27492148

  8. PKM2 enhances chemosensitivity to cisplatin through interaction with the mTOR pathway in cervical cancer

    PubMed Central

    Zhu, Haiyan; Wu, Jun; Zhang, Wenwen; Luo, Hui; Shen, Zhaojun; Cheng, Huihui; Zhu, Xueqiong

    2016-01-01

    Pyruvate kinase M2 (PKM2) is a key driver of aerobic glycolysis in cancer cells and has been shown to be up-regulated by mTOR in vitro. Our previous proteomic profiling studies showed that PKM2 was significantly upregulated in cervical cancer tissues after treatment with neoadjuvant chemotherapy (NACT). Whether PKM2 expression predicts cisplatin-based NACT sensitivity and is mTOR dependent in cervical cancer patients remains unclear. Using paired tumor samples (pre- and post-chemotherapy) from 36 cervical cancer patients, we examined mTOR, HIF-1α, c-Myc, and PKM2 expression in cervical cancer samples and investigated the response to cisplatin-based NACT. In addition, we established PKM2 suppressed cervical cancer cell lines and evaluated their sensitivity to cisplatin in vitro. We found that the mTOR/HIF-1α/c-Myc/PKM2 signaling pathway was significantly downregulated in post-chemotherapy cervical cancer tissues. High levels of mTOR, HIF-1α, c-Myc, and PKM2 were associated with a positive chemotherapy response in cervical cancer patients treated with cisplatin-based NACT. In vitro, PKM2 knockdown desensitized cervical cancer cells to cisplatin. Moreover, PKM2 had complex interactions with mTOR pathways. mTOR, HIF1α, c-Myc, and PKM2 expression in cervical cancer may serve as predictive biomarkers to cisplatin-based chemotherapy. PKM2 enhances chemosensitivity to cisplatin through interaction with the mTOR pathway in cervical cancer. PMID:27492148

  9. [An Elderly Patient with Metastatic Breast Cancer Who Developed Severe Adverse Events such as Stomatitis and Interstitial Pneumonia after Everolimus plus Exemestane Treatment].

    PubMed

    Sakiyama, Kana; Yoshida, Takashi; Goto, Yoshinari; Kimura, Morihiko

    2016-06-01

    An 80-year-old woman was diagnosed with right breast cancer with clinical Stage IIIA 6 years previously. She underwent mastectomy and axillary lymph node dissection. The pathological diagnosis was invasive micropapillary carcinoma with lymph node involvement. Immunohistochemically, the tumor was positive for estrogen receptor and progesterone receptor, and negative for HER2. Postoperatively, the patient was treated with adjuvant chemotherapy consisting of cyclophosphamide, epirubicin, 5-fluorouracil, and paclitaxel, followed by endocrine therapy with letrozole. Four years after surgery, she experienced a recurrence of breast cancer in the thoracic wall, and was treated with exemestane, toremifene, and fulvestrant for 1 year and 5 months. However, she developed carcinomatous pleurisy and was treated with eribulin. This last treatment was ineffective. Subsequently, she received combination therapy with everolimus and exemestane. Although the pleural effusion reduced markedly after 5 weeks, stomatitis, diarrhea, melena, and interstitial pneumonia occurred as adverse events. The symptoms improved after drug discontinuation and steroid therapy. The combination therapy with everolimus and exemestane is a prospective therapy for hormone-resistant recurrent breast cancer, but the management of adverse events is very important. PMID:27306814

  10. Efficacy and Safety of Low-Dose Cyclosporine with Everolimus and Steroids in de novo Heart Transplant Patients: A Multicentre, Randomized Trial

    PubMed Central

    Zuckermann, Andreas; Wang, Shoei-Shen; Ross, Heather; Frigerio, Maria; Eisen, Howard J.; Bara, Christoph; Hoefer, Daniel; Cotrufo, Maurizio; Dong, Gaohong; Junge, Guido; Keogh, Anne M.

    2011-01-01

    A six-month, multicenter, randomized, open-label study was undertaken to determine whether renal function is improved using reduced-exposure cyclosporine (CsA) versus standard-exposure CsA in 199 de novo heart transplant patients receiving everolimus and steroids ± induction therapy. Mean C2 levels were at the low end of the target range in standard-exposure patients (n = 100) and exceeded target range in reduced-exposure patients (n = 99) throughout the study. Mean serum creatinine at Month 6 (the primary endpoint) was 141.0 ± 53.1 μmol/L in standard-exposure patients versus 130.1 ± 53.7 μmol/L in reduced-exposure patients (P = 0.093). The incidence of biopsy-proven acute rejection ≥3A at Month 6 was 21.0% (21/100) in the standard-exposure group and 16.2% (16/99) in the reduced-exposure group (n.s.). Adverse events and infections were similar between treatment groups. Thus, everolimus with reduced-exposure CsA resulted in comparable efficacy compared to standard-exposure CsA. No renal function benefits were demonstrated; that is possibly related to poor adherence to reduced CsA exposure. PMID:22295178

  11. Everolimus-eluting bioresorbable stent vs. durable polymer everolimus-eluting metallic stent in patients with ST-segment elevation myocardial infarction: results of the randomized ABSORB ST-segment elevation myocardial infarction—TROFI II trial

    PubMed Central

    Sabaté, Manel; Windecker, Stephan; Iñiguez, Andres; Okkels-Jensen, Lisette; Cequier, Angel; Brugaletta, Salvatore; Hofma, Sjoerd H.; Räber, Lorenz; Christiansen, Evald Høi; Suttorp, Maarten; Pilgrim, Thomas; Anne van Es, Gerrit; Sotomi, Yohei; García-García, Hector M.; Onuma, Yoshinobu; Serruys, Patrick W.

    2016-01-01

    Aims Patients with ST-segment elevation myocardial infarction (STEMI) feature thrombus-rich lesions with large necrotic core, which are usually associated with delayed arterial healing and impaired stent-related outcomes. The use of bioresorbable vascular scaffolds (Absorb) has the potential to overcome these limitations owing to restoration of native vessel lumen and physiology at long term. The purpose of this randomized trial was to compare the arterial healing response at short term, as a surrogate for safety and efficacy, between the Absorb and the metallic everolimus-eluting stent (EES) in patients with STEMI. Methods and results ABSORB-STEMI TROFI II was a multicentre, single-blind, non-inferiority, randomized controlled trial. Patients with STEMI who underwent primary percutaneous coronary intervention were randomly allocated 1:1 to treatment with the Absorb or EES. The primary endpoint was the 6-month optical frequency domain imaging healing score (HS) based on the presence of uncovered and/or malapposed stent struts and intraluminal filling defects. Main secondary endpoint included the device-oriented composite endpoint (DOCE) according to the Academic Research Consortium definition. Between 06 January 2014 and 21 September 2014, 191 patients (Absorb [n = 95] or EES [n = 96]; mean age 58.6 years old; 17.8% females) were enrolled at eight centres. At 6 months, HS was lower in the Absorb arm when compared with EES arm [1.74 (2.39) vs. 2.80 (4.44); difference (90% CI) −1.06 (−1.96, −0.16); Pnon-inferiority <0.001]. Device-oriented composite endpoint was also comparably low between groups (1.1% Absorb vs. 0% EES). One case of definite subacute stent thrombosis occurred in the Absorb arm (1.1% vs. 0% EES; P = ns). Conclusion Stenting of culprit lesions with Absorb in the setting of STEMI resulted in a nearly complete arterial healing which was comparable with that of metallic EES at 6 months. These findings provide the basis for further exploration in

  12. Identification of a Non-Gatekeeper Hot Spot for Drug-Resistant Mutations in mTOR Kinase.

    PubMed

    Wu, Tzung-Ju; Wang, Xiaowen; Zhang, Yanjie; Meng, Linghua; Kerrigan, John E; Burley, Stephen K; Zheng, X F Steven

    2015-04-21

    Protein kinases are therapeutic targets for human cancer. However, "gatekeeper" mutations in tyrosine kinases cause acquired clinical resistance, limiting long-term treatment benefits. mTOR is a key cancer driver and drug target. Numerous small-molecule mTOR kinase inhibitors have been developed, with some already in human clinical trials. Given our clinical experience with targeted therapeutics, acquired drug resistance in mTOR is thought likely, but not yet documented. Herein, we describe identification of a hot spot (L2185) for drug-resistant mutations, which is distinct from the gatekeeper site, and a chemical scaffold refractory to drug-resistant mutations. We also provide new insights into mTOR kinase structure and function. The hot spot mutations are potentially useful as surrogate biomarkers for acquired drug resistance in ongoing clinical trials and future treatments and for the design of the next generation of mTOR-targeted drugs. Our study provides a foundation for further research into mTOR kinase function and targeting. PMID:25865887

  13. Gingipain-dependent degradation of mTOR pathway proteins by the periodontal pathogen Porphyromonas gingivalis during invasion

    PubMed Central

    Stafford, Prachi; Higham, Jon; Pinnock, Abigail; Murdoch, Craig; Douglas, C. W. Ian; Stafford, Graham P; Lambert, Daniel W

    2014-01-01

    SUMMARY Porphyromonas gingivalis and Tannerella forsythia are Gram-negative pathogens strongly associated with periodontitis. Their abilities to interact, invade and persist within host cells are considered crucial to their pathogenicity, but the mechanisms by which they subvert host defences are not well understood. In this study, we set out to investigate whether P. gingivalis and T. forsythia directly target key signalling molecules which may modulate the host cell phenotype to favour invasion and persistence. Our data identify, for the first time, that P. gingivalis, but not T. forsythia, reduces levels of intracellular mammalian target of rapamycin (mTOR) in oral epithelial cells following invasion over a 4 hour time course, via the action of gingipains. The ability of cytochalasin D to abrogate P. gingivalis-mediated mTOR degradation suggests that this effect is dependent upon cellular invasion. We also show that levels of several other proteins in the mTOR signalling pathway are modulated by gingipains, either directly or as a consequence of mTOR degradation including p-4E-BP1. Taken together, our data suggests that P. gingivalis manipulates the mTOR pathway, providing evidence for a potentially novel mechanism by which P. gingivalis mediates its effects on host cell responses to infection. PMID:23714361

  14. Discovering new mTOR inhibitors for cancer treatment through virtual screening methods and in vitro assays

    NASA Astrophysics Data System (ADS)

    Wang, Ling; Chen, Lei; Yu, Miao; Xu, Li-Hui; Cheng, Bao; Lin, Yong-Sheng; Gu, Qiong; He, Xian-Hui; Xu, Jun

    2016-01-01

    Mammalian target of rapamycin (mTOR) is an attractive target for new anticancer drug development. We recently developed in silico models to distinguish mTOR inhibitors and non-inhibitors. In this study, we developed an integrated strategy for identifying new mTOR inhibitors using cascaded in silico screening models. With this strategy, fifteen new mTOR kinase inhibitors including four compounds with IC50 values below 10 μM were discovered. In particular, compound 17 exhibited potent anticancer activities against four tumor cell lines, including MCF-7, HeLa, MGC-803, and C6, with IC50 values of 1.90, 2.74, 3.50 and 11.05 μM. Furthermore, cellular studies and western blot analyses revealed that 17 induces cell death via apoptosis by targeting both mTORC1 and mTORC2 within cells and arrests the cell cycle of HeLa at the G1/G0-phase. Finally, multi-nanosecond explicit solvent simulations and MM/GBSA analyses were carried out to study the inhibitory mechanisms of 13, 17, and 40 for mTOR. The potent compounds presented here are worthy of further investigation.

  15. mTOR kinase inhibitors synergize with histone deacetylase inhibitors to kill B-cell acute lymphoblastic leukemia cells.

    PubMed

    Beagle, Brandon R; Nguyen, Duc M; Mallya, Sharmila; Tang, Sarah S; Lu, Mengrou; Zeng, Zhihong; Konopleva, Marina; Vo, Thanh-Trang; Fruman, David A

    2015-02-10

    High activity of the mechanistic target of rapamycin (mTOR) is associated with poor prognosis in pre-B-cell acute lymphoblastic leukemia (B-ALL), suggesting that inhibiting mTOR might be clinically useful. However, emerging data indicate that mTOR inhibitors are most effective when combined with other target agents. One strategy is to combine with histone deacetylase (HDAC) inhibitors, since B-ALL is often characterized by epigenetic changes that silence the expression of pro-apoptotic factors. Here we tested combinations of mTOR and pan-HDAC inhibitors on B-ALL cells, including both Philadelphia chromosome-positive (Ph+) and non-Ph cell lines. We found that mTOR kinase inhibitors (TOR-KIs) synergize with HDAC inhibitors to cause apoptosis in B-ALL cells and the effect is greater when compared to rapamycin plus HDAC inhibitors. The combination of TOR-KIs with the clinically approved HDAC inhibitor vorinostat increased apoptosis in primary pediatric B-ALL cells in vitro. Mechanistically, TOR-KI and HDAC inhibitor combinations increased expression of pro-death genes, including targets of the Forkhead Box O (FOXO) transcription factors, and increased sensitivity to apoptotic triggers at the mitochondria. These findings suggest that targeting epigenetic factors can unmask the cytotoxic potential of TOR-KIs towards B-ALL cells. PMID:25576920

  16. mTOR signaling promotes stem cell activation via counterbalancing BMP-mediated suppression during hair regeneration.

    PubMed

    Deng, Zhili; Lei, Xiaohua; Zhang, Xudong; Zhang, Huishan; Liu, Shuang; Chen, Qi; Hu, Huimin; Wang, Xinyue; Ning, Lina; Cao, Yujing; Zhao, Tongbiao; Zhou, Jiaxi; Chen, Ting; Duan, Enkui

    2015-02-01

    Hair follicles (HFs) undergo cycles of degeneration (catagen), rest (telogen), and regeneration (anagen) phases. Anagen begins when the hair follicle stem cells (HFSCs) obtain sufficient activation cues to overcome suppressive signals, mainly the BMP pathway, from their niche cells. Here, we unveil that mTOR complex 1 (mTORC1) signaling is activated in HFSCs, which coincides with the HFSC activation at the telogen-to-anagen transition. By using both an inducible conditional gene targeting strategy and a pharmacological inhibition method to ablate or inhibit mTOR signaling in adult skin epithelium before anagen initiation, we demonstrate that HFs that cannot respond to mTOR signaling display significantly delayed HFSC activation and extended telogen. Unexpectedly, BMP signaling activity is dramatically prolonged in mTOR signaling-deficient HFs. Through both gain- and loss-of-function studies in vitro, we show that mTORC1 signaling negatively affects BMP signaling, which serves as a main mechanism whereby mTORC1 signaling facilitates HFSC activation. Indeed, in vivo suppression of BMP by its antagonist Noggin rescues the HFSC activation defect in mTORC1-null skin. Our findings reveal a critical role for mTOR signaling in regulating stem cell activation through counterbalancing BMP-mediated repression during hair regeneration. PMID:25609845

  17. Reduced AMPK-ACC and mTOR signaling in muscle from older men, and effect of resistance exercise.

    PubMed

    Li, Mengyao; Verdijk, Lex B; Sakamoto, Kei; Ely, Brian; van Loon, Luc J C; Musi, Nicolas

    2012-01-01

    AMP-activated protein kinase (AMPK) is a key energy-sensitive enzyme that controls numerous metabolic and cellular processes. Mammalian target of rapamycin (mTOR) is another energy/nutrient-sensitive kinase that controls protein synthesis and cell growth. In this study we determined whether older versus younger men have alterations in the AMPK and mTOR pathways in skeletal muscle, and examined the effect of a long term resistance type exercise training program on these signaling intermediaries. Older men had decreased AMPKα2 activity and lower phosphorylation of AMPK and its downstream signaling substrate acetyl-CoA carboxylase (ACC). mTOR phosphylation also was reduced in muscle from older men. Exercise training increased AMPKα1 activity in older men, however, AMPKα2 activity, and the phosphorylation of AMPK, ACC and mTOR, were not affected. In conclusion, older men have alterations in the AMPK-ACC and mTOR pathways in muscle. In addition, prolonged resistance type exercise training induces an isoform-selective up regulation of AMPK activity. PMID:23000302

  18. mTOR regulates TLR-induced c-fos and Th1 responses to HBV and HCV vaccines.

    PubMed

    He, Li; Zang, Aiping; Du, Min; Ma, Dapeng; Yuan, Chuanping; Zhou, Chun; Mu, Jing; Shi, Huanjing; Li, Dapeng; Huang, Xulin; Deng, Qiang; Xiao, Jianhua; Yan, Huimin; Hui, Lijian; Lan, Ke; Xiong, Sidong; Li, Xiaoxia; Huang, Zhong; Xiao, Hui

    2015-06-01

    Although IL-12 plays a critical role in priming Th1 and cytotoxic T lymphocyte (CTL) responses, Toll-like receptor (TLR) signaling only induces low amounts of IL-12 in dendritic cells and macrophages, implying the existence of stringent regulatory mechanisms. In this study, we sought to uncover the mechanisms underlying TLR-induced IL-12 expression and the Th1 response. By systemic screening, we identified a number of protein kinases involved in the regulation of TLRinduced IL-12 expression. In particular, PI3K, ERK, and mTOR play critical roles in the TLR-induced Th1 response by regulating IL-12 and IL-10 production in innate immune cells. Moreover, we identified c-fos as a key molecule that mediates mTOR-regulated IL-12 and IL-10 expression in TLR signaling. Mechanistically, mTOR plays a crucial role in c-fos expression, thereby modulating NFκB binding to promoters of IL-12 and IL-10. By controlling the expression of a special innate gene program, mTOR can specifically regulate the TLR-induced T cell response in vivo. Furthermore, blockade of mTOR by rapamycin efficiently boosted TLR-induced antigen-specific T and B cell responses to HBV and HCV vaccines. Taken together, these results reveal a novel mechanism through which mTOR regulates TLR-induced IL-12 and IL-10 production, contributing new insights for strategies to improve vaccine efficacy. PMID:26122641

  19. Discovering new mTOR inhibitors for cancer treatment through virtual screening methods and in vitro assays

    PubMed Central

    Wang, Ling; Chen, Lei; Yu, Miao; Xu, Li-Hui; Cheng, Bao; Lin, Yong-Sheng; Gu, Qiong; He, Xian-Hui; Xu, Jun

    2016-01-01

    Mammalian target of rapamycin (mTOR) is an attractive target for new anticancer drug development. We recently developed in silico models to distinguish mTOR inhibitors and non-inhibitors. In this study, we developed an integrated strategy for identifying new mTOR inhibitors using cascaded in silico screening models. With this strategy, fifteen new mTOR kinase inhibitors including four compounds with IC50 values below 10 μM were discovered. In particular, compound 17 exhibited potent anticancer activities against four tumor cell lines, including MCF-7, HeLa, MGC-803, and C6, with IC50 values of 1.90, 2.74, 3.50 and 11.05 μM. Furthermore, cellular studies and western blot analyses revealed that 17 induces cell death via apoptosis by targeting both mTORC1 and mTORC2 within cells and arrests the cell cycle of HeLa at the G1/G0-phase. Finally, multi-nanosecond explicit solvent simulations and MM/GBSA analyses were carried out to study the inhibitory mechanisms of 13, 17, and 40 for mTOR. The potent compounds presented here are worthy of further investigation. PMID:26732172

  20. Regulation of YAP by mTOR and autophagy reveals a therapeutic target of tuberous sclerosis complex

    PubMed Central

    Liang, Ning; Zhang, Chi; Dill, Patricia; Panasyuk, Ganna; Pion, Delphine; Koka, Vonda; Gallazzini, Morgan; Olson, Eric N.; Lam, Hilaire; Henske, Elizabeth P.; Dong, Zheng; Apte, Udayan; Pallet, Nicolas; Johnson, Randy L.; Terzi, Fabiola; Kwiatkowski, David J.; Scoazec, Jean-Yves; Martignoni, Guido

    2014-01-01

    Genetic studies have shown that the tuberous sclerosis complex (TSC) 1–TSC2–mammalian target of Rapamycin (mTOR) and the Hippo–Yes-associated protein 1 (YAP) pathways are master regulators of organ size, which are often involved in tumorigenesis. The crosstalk between these signal transduction pathways in coordinating environmental cues, such as nutritional status and mechanical constraints, is crucial for tissue growth. Whether and how mTOR regulates YAP remains elusive. Here we describe a novel mouse model of TSC which develops renal mesenchymal lesions recapitulating human perivascular epithelioid cell tumors (PEComas) from patients with TSC. We identify that YAP is up-regulated by mTOR in mouse and human PEComas. YAP inhibition blunts abnormal proliferation and induces apoptosis of TSC1–TSC2-deficient cells, both in culture and in mosaic Tsc1 mutant mice. We further delineate that YAP accumulation in TSC1/TSC2-deficient cells is due to impaired degradation of the protein by the autophagosome/lysosome system. Thus, the regulation of YAP by mTOR and autophagy is a novel mechanism of growth control, matching YAP activity with nutrient availability under growth-permissive conditions. YAP may serve as a potential therapeutic target for TSC and other diseases with dysregulated mTOR activity. PMID:25288394

  1. Co-regulation of SREBP-1 and mTOR ameliorates lipid accumulation in kidney of diabetic mice.

    PubMed

    Wang, Hui; Zhu, Lin; Hao, Jun; Duan, Huijun; Liu, Shuxia; Zhao, Song; Liu, Qingjuan; Liu, Wei

    2015-08-01

    SREBP-1 and mTOR have been proved to involve in renal lipid metabolism of diabetes mellitus. In the present study, we investigated the effect of co-regulation of SREBP-1 and mTOR on renal lipid metabolism using diabetic mice and cultured renal tubular cells. The results showed that compared with those in high glucose-stimulated HKC cells single transfected with shRNA-SREBP-1 vector, the level of SREBP-1 protein were significantly reduced by 64.1% followed by decreased FASN mRNA, ACC mRNA, ADRP protein and lipid droplets in HKC cells co-transfected with shRNA-SREBP-1 vector and kinase-dead mTOR vector. Furthermore, diabetic mice co-injected with shRNA-SREBP-1 vector and kinase-dead mTOR vector showed that renal SREBP-1 protein, FASN mRNA and ACC mRNA were respectively decreased by 34.6%, 45.9%, 22.0% in comparison with those in diabetic mice single injected with shRNA-SREBP-1 vector accompanied by reduced ADRP protein and triglyceride content. In the end our study suggests that co-regulation of SREBP-1 and mTOR in kidney of diabetic mice is more effective in lowering renal lipogenesis than only regulation of SREBP-1. PMID:26112216

  2. Discovering new mTOR inhibitors for cancer treatment through virtual screening methods and in vitro assays.

    PubMed

    Wang, Ling; Chen, Lei; Yu, Miao; Xu, Li-Hui; Cheng, Bao; Lin, Yong-Sheng; Gu, Qiong; He, Xian-Hui; Xu, Jun

    2016-01-01

    Mammalian target of rapamycin (mTOR) is an attractive target for new anticancer drug development. We recently developed in silico models to distinguish mTOR inhibitors and non-inhibitors. In this study, we developed an integrated strategy for identifying new mTOR inhibitors using cascaded in silico screening models. With this strategy, fifteen new mTOR kinase inhibitors including four compounds with IC50 values below 10 μM were discovered. In particular, compound 17 exhibited potent anticancer activities against four tumor cell lines, including MCF-7, HeLa, MGC-803, and C6, with IC50 values of 1.90, 2.74, 3.50 and 11.05 μM. Furthermore, cellular studies and western blot analyses revealed that 17 induces cell death via apoptosis by targeting both mTORC1 and mTORC2 within cells and arrests the cell cycle of HeLa at the G1/G0-phase. Finally, multi-nanosecond explicit solvent simulations and MM/GBSA analyses were carried out to study the inhibitory mechanisms of 13, 17, and 40 for mTOR. The potent compounds presented here are worthy of further investigation. PMID:26732172

  3. Chemical Inhibitors and microRNAs (miRNA) Targeting the Mammalian Target of Rapamycin (mTOR) Pathway: Potential for Novel Anticancer Therapeutics

    PubMed Central

    AlQurashi, Naif; Hashimi, Saeed M.; Wei, Ming Q.

    2013-01-01

    The mammalian target of rapamycin (mTOR) is a critical regulator of many fundamental features in response to upstream cellular signals, such as growth factors, energy, stress and nutrients, controlling cell growth, proliferation and metabolism through two complexes, mTORC1 and mTORC2. Dysregulation of mTOR signalling often occurs in a variety of human malignant diseases making it a crucial and validated target in the treatment of cancer. Tumour cells have shown high susceptibility to mTOR inhibitors. Rapamycin and its derivatives (rapalogs) have been tested in clinical trials in several tumour types and found to be effective as anticancer agents in patients with advanced cancers. To block mTOR function, they form a complex with FKBP12 and then bind the FRB domain of mTOR. Furthermore, a new generation of mTOR inhibitors targeting ATP-binding in the catalytic site of mTOR showed potent and more selective inhibition. More recently, microRNAs (miRNA) have emerged as modulators of biological pathways that are essential in cancer initiation, development and progression. Evidence collected to date shows that miRNAs may function as tumour suppressors or oncogenes in several human neoplasms. The mTOR pathway is a promising target by miRNAs for anticancer therapy. Extensive studies have indicated that regulation of the mTOR pathway by miRNAs plays a major role in cancer progression, indicating a novel way to investigate the tumorigenesis and therapy of cancer. Here, we summarize current findings of the role of mTOR inhibitors and miRNAs in carcinogenesis through targeting mTOR signalling pathways and determine their potential as novel anti-cancer therapeutics. PMID:23434669

  4. mTOR mediates human trophoblast invasion through regulation of matrix-remodeling enzymes and is associated with serine phosphorylation of STAT3

    SciTech Connect

    Busch, Susann; Renaud, Stephen J.; Schleussner, Ekkehard; Graham, Charles H.; Markert, Udo R.

    2009-06-10

    The intracellular signaling molecule mammalian target of rapamycin (mTOR) is essential for cell growth and proliferation. It is involved in mouse embryogenesis, murine trophoblast outgrowth and linked to tumor cell invasiveness. In order to assess the role of mTOR in human trophoblast invasion we analyzed the in vitro invasiveness of HTR-8/SVneo immortalized first-trimester trophoblast cells in conjunction with enzyme secretion upon mTOR inhibition and knockdown of mTOR protein expression. Additionally, we also tested the capability of mTOR to trigger signal transducer and activator of transcription (STAT)-3 by its phosphorylation status. Rapamycin inhibited mTOR kinase activity as demonstrated with a lower phosphorylation level of the mTOR substrate p70 S6 kinase (S6K). With the use of rapamycin and siRNA-mediated mTOR knockdown we could show that cell proliferation, invasion and secretion of matrix-metalloproteinases (MMP)-2 and -9, urokinase-like plasminogen activator (uPA) and its major physiological uPA inhibitor (PAI)-1 were inhibited. While tyrosine phosphorylation of STAT3 was unaffected by mTOR inhibition and knockdown, serine phosphorylation was diminished. We conclude that mTOR signaling is one major mechanism in a tightly regulated network of intracellular signal pathways including the JAK/STAT system to regulate invasion in human trophoblast cells by secretion of enzymes that remodel the extra-cellular matrix (ECM) such as MMP-2, -9, uPA and PAI-1. Dysregulation of mTOR may contribute to pregnancy-related pathologies caused through impaired trophoblast invasion.

  5. ARG2 impairs endothelial autophagy through regulation of MTOR and PRKAA/AMPK signaling in advanced atherosclerosis

    PubMed Central

    Xiong, Yuyan; Yepuri, Gautham; Forbiteh, Michael; Yu, Yi; Montani, Jean-Pierre; Yang, Zhihong; Ming, Xiu-Fen

    2015-01-01

    Impaired autophagy function and enhanced ARG2 (arginase 2)-MTOR (mechanistic target of rapamycin) crosstalk are implicated in vascular aging and atherosclerosis. We are interested in the role of ARG2 and the potential underlying mechanism(s) in modulation of endothelial autophagy. Using human nonsenescent “young” and replicative senescent endothelial cells as well as Apolipoprotein E-deficient (apoe−/−Arg2+/+) and Arg2-deficient apoe−/− (apoe−/−arg2−/−) mice fed a high-fat diet for 10 wk as the atherosclerotic animal model, we show here that overexpression of ARG2 in the young cells suppresses endothelial autophagy with concomitant enhanced expression of RICTOR, the essential component of the MTORC2 complex, leading to activation of the AKT-MTORC1-RPS6KB1/S6K1 (ribosomal protein S6 kinase, 70kDa, polypeptide 1) cascade and inhibition of PRKAA/AMPK (protein kinase, AMP-activated, α catalytic subunit). Expression of an inactive ARG2 mutant (H160F) had the same effect. Moreover, silencing RPS6KB1 or expression of a constitutively active PRKAA prevented autophagy suppression by ARG2 or H160F. In senescent cells, enhanced ARG2-RICTOR-AKT-MTORC1-RPS6KB1 and decreased PRKAA signaling and autophagy were observed, which was reversed by silencing ARG2 but not by arginase inhibitors. In line with the above observations, genetic ablation of Arg2 in apoe−/− mice reduced RPS6KB1, enhanced PRKAA signaling and endothelial autophagy in aortas, which was associated with reduced atherosclerosis lesion formation. Taken together, the results demonstrate that ARG2 impairs endothelial autophagy independently of the L-arginine ureahydrolase activity through activation of RPS6KB1 and inhibition of PRKAA, which is implicated in atherogenesis. PMID:25484082

  6. Alcohol intoxication following muscle contraction in mice decreases muscle protein synthesis but not mTOR signal transduction

    PubMed Central

    Steiner, Jennifer L.; Lang, Charles H.

    2014-01-01

    Background Alcohol [ethanol (EtOH)] intoxication antagonizes stimulation of muscle protein synthesis and mTOR signaling. However, whether the anabolic response can be reversed when alcohol is consumed after the stimulus is unknown. Methods A single bout of electrically stimulated muscle contractions (10 sets of 6 contractions) were induced in fasted male C57BL/6 mice 2 h prior to alcohol intoxication. EtOH was injected IP (3g/kg) and the gastrocnemius/plantaris muscle complex was collected 2 h later from the stimulated and contralateral unstimulated control leg. Results Muscle contraction increased protein synthesis 28% in control mice while EtOH abolished this stimulation-induced increase. Further, EtOH suppressed the rate of synthesis ~75% compared to control muscle irrespective of stimulation. This decrease was associated with impaired protein elongation as EtOH increased the phosphorylation of eEF2 Thr56. In contrast, stimulation-induced increases in mTORC1 (S6K1 Thr421/Ser424, S6K1 Thr389, rpS6 Ser240/244, 4E-BP1 Thr37/46) and MAPK (JNK Thr183/Tyr185, p38 Thr180/Tyr182, and rpS6S235/236) signaling were not reversed by acute EtOH. Conclusion These data suggest that EtOH-induced decreases in protein synthesis in fasted mice may be independent of mTORC1 and MAPK signaling following muscle contraction and instead due to the antagonistic actions of EtOH on mRNA translation elongation. Therefore, EtOH suppresses the contraction-induced increase in protein synthesis and over time has the potential to prevent skeletal muscle hypertrophy induced by repeated muscle contraction. PMID:25623400

  7. Resveratrol activates autophagic cell death in prostate cancer cells via downregulation of STIM1 and the mTOR pathway.

    PubMed

    Selvaraj, Senthil; Sun, Yuyang; Sukumaran, Pramod; Singh, Brij B

    2016-05-01

    Resveratrol (RSV), a natural polyphenol, has been suggested to induce cell cycle arrest and activate apoptosis-mediated cell death in several cancer cells, including prostate cancer. However, several molecular mechanisms have been proposed on its chemopreventive action, the precise mechanisms by which RSV exerts its anti-proliferative effect in androgen-independent prostate cancer cells remain questionable. In the present study, we show that RSV activates autophagic cell death in PC3 and DU145 cells, which was dependent on stromal interaction molecule 1 (STIM1) expression. RSV treatment decreases STIM1 expression in a time-dependent manner and attenuates STIM1 association with TRPC1 and Orai1. Furthermore, RSV treatment also decreases ER calcium storage and store operated calcium entry (SOCE), which induces endoplasmic reticulum (ER) stress, thereby, activating AMPK and inhibiting the AKT/mTOR pathway. Similarly, inhibition of SOCE by SKF-96365 decreases the survival and proliferation of PC3 and DU145 cells and inhibits AKT/mTOR pathway and induces autophagic cell death. Importantly, SOCE inhibition and subsequent autophagic cell death caused by RSV was reversed by STIM1 overexpression. STIM1 overexpression restored SOCE, prevents the loss of mTOR phosphorylation and decreased the expression of CHOP and LC3A in PC3 cells. Taken together, for the first time, our results revealed that RSV induces autophagy-mediated cell death in PC3 and DU145 cells through regulation of SOCE mechanisms, including downregulating STIM1 expression and trigger ER stress by depleting ER calcium pool. © 2015 The Authors. Molecular Carcinogenesis, published by Wiley Periodicals, Inc. PMID:25917875

  8. Dose-dependent effects of mTOR inhibition on weight and mitochondrial disease in mice

    PubMed Central

    Johnson, Simon C.; Yanos, Melana E.; Bitto, Alessandro; Castanza, Anthony; Gagnidze, Arni; Gonzalez, Brenda; Gupta, Kanav; Hui, Jessica; Jarvie, Conner; Johnson, Brittany M.; Letexier, Nicolas; McCanta, Lanny; Sangesland, Maya; Tamis, Oliver; Uhde, Lauren; Van Den Ende, Alex; Rabinovitch, Peter S.; Suh, Yousin; Kaeberlein, Matt

    2015-01-01

    Rapamycin extends lifespan and attenuates age-related pathologies in mice when administered through diet at 14 parts per million (PPM). Recently, we reported that daily intraperitoneal injection of rapamycin at 8 mg/kg attenuates mitochondrial disease symptoms and progression in the Ndufs4 knockout mouse model of Leigh Syndrome. Although rapamycin is a widely used pharmaceutical agent dosage has not been rigorously examined and no dose-response profile has been established. Given these observations we sought to determine if increased doses of oral rapamycin would result in more robust impact on mTOR driven parameters. To test this hypothesis, we compared the effects of dietary rapamycin at doses ranging from 14 to 378 PPM on developmental weight in control and Ndufs4 knockout mice and on health and survival in the Ndufs4 knockout model. High dose rapamycin was well tolerated, dramatically reduced weight gain during development, and overcame gender differences. The highest oral dose, approximately 27-times the dose shown to extend murine lifespan, increased survival in Ndufs4 knockout mice similarly to daily rapamycin injection without observable adverse effects. These findings have broad implications for the effective use of rapamycin in murine studies and for the translational potential of rapamycin in the treatment of mitochondrial disease. This data, further supported by a comparison of available literature, suggests that 14 PPM dietary rapamycin is a sub-optimal dose for targeting mTOR systemically in mice. Our findings suggest that the role of mTOR in mammalian biology may be broadly underestimated when determined through treatment with rapamycin at commonly used doses. PMID:26257774

  9. Transient activation of mTOR following forced treadmill exercise in rats.

    PubMed

    Elfving, Betina; Christensen, Tina; Ratner, Cecilia; Wienecke, Jacob; Klein, Anders B

    2013-09-01

    The beneficial effect of exercise on hippocampal plasticity is possibly mediated by increased angiogenesis and neurogenesis. In angiogenesis, insulin-like growth factor-1 (IGF-1), vascular endothelial growth factor (VEGF), and hypoxia-inducible factor 1, alpha subunit (HIF1α) are important factors, while the induction of neurogenesis requires signaling through the VEGF receptor, Flk-1 (VEGFR-2). VEGF expression is believed to be regulated by two distinct mTOR (mammalian target of Rapamycin)-containing multiprotein complexes mTORC1 and mTORC2, respectively. This study was initiated to investigate the effect of exercise on the expression of VEGF, cognate receptors, HIF1α, mTORC1, and mTORC2 in hippocampus and frontal cortex. To this end, we measured messenger RNA (mRNA) levels in rat brain using quantitative real-time polymerase chain reaction (real-time qPCR) after forced treadmill exercise for 1 day, 2 weeks, and 8 weeks. Rats were euthanized either immediately (0 h) or 24 h after last exercise session. Here, we show that exercise affected mRNA levels of VEGF, VEGFR2, and the coreceptor neuropilin 2 (NRP2) when the rats were euthanized immediately, whereas at 24 h only the expression of mTOR was regulated after a single bout of exercise. In conclusion, the effect of treadmill exercise on the VEGF system is acute rather than chronic and there is a transient activation of mTOR. More studies are needed to understand whether this could be beneficial in the treatment of neuropsychiatric disorders. PMID:23536493

  10. Bridges between mitochondrial oxidative stress, ER stress and mTOR signaling in pancreatic β cells.

    PubMed

    Wang, Jing; Yang, Xin; Zhang, Jingjing

    2016-08-01

    Pancreatic β cell dysfunction, i.e., failure to provide insulin in concentrations sufficient to control blood sugar, is central to the etiology of all types of diabetes. Current evidence implicates mitochondrial oxidative stress and endoplasmic reticulum (ER) stress in pancreatic β cell loss and impaired insulin secretion. Oxidative and ER stress are interconnected so that misfolded proteins induce reactive oxygen species (ROS) production; likewise, oxidative stress disturbs the ER redox state thereby disrupting correct disulfide bond formation and proper protein folding. mTOR signaling regulates many metabolic processes including protein synthesis, cell growth, survival and proliferation. Oxidative stress inhibits mTORC1, which is considered an important suppressor of mitochondrial oxidative stress in β cells, and ultimately, controls cell survival. The interplay between ER stress and mTORC1 is complicated, since the unfolded protein response (UPR) activation can occur upstream or downstream of mTORC1. Persistent activation of mTORC1 initiates protein synthesis and UPR activation, while in the later phase induces ER stress. Chronic activation of ER stress inhibits Akt/mTORC1 pathway, while under particular settings, acute activation of UPR activates Akt-mTOR signaling. Thus, modulating mitochondrial oxidative stress and ER stress via mTOR signaling may be an approach that will effectively suppress obesity- or glucolipotoxicity-induced metabolic disorders such as insulin resistance and type 2 diabetes mellitus (T2DM). In this review, we focus on the regulations between mTOR signaling and mitochondrial oxidative or ER stress in pancreatic β cells. PMID:27185188

  11. Identification of Protor as a novel Rictor-binding component of mTOR complex-2

    PubMed Central

    Pearce, Laura R.; Huang, Xu; Boudeau, Jérôme; Pawłowski, Rafał; Wullschleger, Stephan; Deak, Maria; Ibrahim, Adel F. M.; Gourlay, Robert; Magnuson, Mark A.; Alessi, Dario R.

    2007-01-01

    The mTOR (mammalian target of rapamycin) protein kinase is an important regulator of cell growth. Two complexes of mTOR have been identified: complex 1, consisting of mTOR–Raptor (regulatory associated protein of mTOR)–mLST8 (termed mTORC1), and complex 2, comprising mTOR–Rictor (rapamycininsensitive companion of mTOR)–mLST8–Sin1 (termed mTORC2). mTORC1 phosphorylates the p70 ribosomal S6K (S6 kinase) at its hydrophobic motif (Thr389), whereas mTORC2 phosphorylates PKB (protein kinase B) at its hydrophobic motif (Ser473). In the present study, we report that widely expressed isoforms of unstudied proteins termed Protor-1 (protein observed with Rictor-1) and Protor-2 interact with Rictor and are components of mTORC2. We demonstrate that immunoprecipitation of Protor-1 or Protor-2 results in the co-immunoprecipitation of other mTORC2 subunits, but not Raptor, a specific component of mTORC1. We show that detergents such as Triton X-100 or n-octylglucoside dissociate mTOR and mLST8 from a complex of Protor-1, Sin1 and Rictor. We also provide evidence that Rictor regulates the expression of Protor-1, and that Protor-1 is not required for the assembly of other mTORC2 subunits into a complex. Protor-1 is a novel Rictor-binding subunit of mTORC2, but further work is required to establish its role. PMID:17461779

  12. Leucine minimizes denervation-induced skeletal muscle atrophy of rats through akt/mtor signaling pathways

    PubMed Central

    Ribeiro, Carolina B.; Christofoletti, Daiane C.; Pezolato, Vitor A.; de Cássia Marqueti Durigan, Rita; Prestes, Jonato; Tibana, Ramires A.; Pereira, Elaine C. L.; de Sousa Neto, Ivo V.; Durigan, João L. Q.; da Silva, Carlos A.

    2015-01-01

    The aim of the present study was to evaluate the effect of leucine treatment (0.30 mM) on muscle weight and signaling of myoproteins related to synthesis and degradation pathways of soleus muscle following seven days of complete sciatic nerve lesion. Wistar rats (n = 24) of 3–4 months of age (192 ± 23 g) were used. The animals were randomly distributed into four experimental groups (n = 6/group): control, treated with leucine (L), denervated (D) and denervated treated with leucine (DL). Dependent measures were proteins levels of AKT, AMPK, mTOR, and ACC performed by Western blot. Leucine induced a reduction in the phosphorylation of AMPK (p < 0.05) by 16% in the L and by 68% in the DL groups as compared with control group. Denervation increased AMPK by 24% in the D group as compared with the control group (p < 0.05). AKT was also modulated by denervation and leucine treatment, highlighted by the elevation of AKT phosphorylation in the D (65%), L (98%) and DL (146%) groups as compared with the control group (p < 0.05). AKT phosphorylation was 49% higher in the D group as compared with the DL group. Furthermore, denervation decreased mTOR phosphorylation by 29% in the D group as compared with the control group. However, leucine treatment induced an increase of 49% in the phosphorylation of mTOR in the L group as compared with the control group, and an increase of 154% in the DL as compared with the D group (p < 0.05). ACC phosphorylation was 20% greater in the D group than the control group. Furthermore, ACC in the soleus was 22% lower in the in the L group and 50% lower in the DL group than the respective control group (p < 0.05). In conclusion, leucine treatment minimized the deleterious effects of denervation on rat soleus muscle by increasing anabolic (AKT and mTOR) and decreasing catabolic (AMPK) pathways. These results may be interesting for muscle recovery following acute denervation, which may contribute to musculoskeletal rehabilitation after denervation

  13. [Update on clinical activity of CCI779 (temsirolimus), mTOR inhibitor].

    PubMed

    Mounier, Nicolas; Vignot, Stéphane; Spano, Jean-Philippe

    2006-11-01

    Temsirolimus (CCI779), an intravenous analog of rapamycin, presents immunosuppressive properties and also antiproliferative activity. Its principal target is the mTOR serine/threonin kinase which controls the initiation of the transcription of many ARNm implicated in carcinogenesis. Breast cancers, glioblastoma and renal cell carcinoma were particularly studied with response rates from 10 to 20 %. In haematology, mantle-cell lymphoma is of particular interest because of constitutional activation of cyclin D1 (response rate of 40 %). As a whole these data define temsirolimus as a promising new drug. Current and further developments are based on its association with chemotherapy in a concomitant or sequential way. PMID:17145584

  14. Genetic variants in the mTOR pathway and breast cancer risk in African American women.

    PubMed

    Cheng, Ting-Yuan David; Ambrosone, Christine B; Hong, Chi-Chen; Lunetta, Kathryn L; Liu, Song; Hu, Qiang; Yao, Song; Sucheston-Campbell, Lara; Bandera, Elisa V; Ruiz-Narváez, Edward A; Haddad, Stephen; Troester, Melissa A; Haiman, Christopher A; Bensen, Jeannette T; Olshan, Andrew F; Palmer, Julie R; Rosenberg, Lynn

    2016-01-01

    The phosphatidylinositol 3-kinase-AKT-mammalian target of rapamycin (mTOR) pathway has been implicated in breast carcinogenesis. However, there has been no large-scale investigation of genetic variants in the mTOR pathway and breast cancer risk. We examined 28847 single-nucleotide polymorphisms (SNPs) in 61 mTOR pathway genes in the African American Breast Cancer Epidemiology and Risk consortium of 3663 cases [1983 estrogen receptor-positive (ER+) and 1098 ER-negative (ER-)] and 4687 controls. Gene-level analyses were conducted using the adaptive rank truncated product (ARTP) test for 10773 SNPs that were not highly correlated (r (2) < 0.8), and SNP-level analyses were conducted with logistic regression. Among genes that were prioritized (nominal P < 0.05, ARTP tests), associations were observed for intronic SNPs TSC2 rs181088346 [odds ratio (OR) of each copy of variant allele = 0.77, 95% confidence interval (CI) = 0.65-0.88 for all breast cancer] and BRAF rs114729114 (OR = 1.53, 95% CI = 1.24-1.91 for all breast cancer and OR = 2.03, 95% CI = 1.50-2.76 for ER- tumors). For ER- tumors, intronic SNPs PGF rs11542848 (OR = 1.38, 95% CI = 1.15-1.66) and rs61759375 (OR = 1.34, 95% CI = 1.14-1.57) and MAPK3 rs78564187 (OR = 1.26, 95% CI = 1.11-1.43) were associated with increased risk. These SNPs were significant at a gene-wide level (Bonferroni-corrected P < 0.05). The variant allele of RPS6KB2 rs35363135, a synonymous coding SNP, was more likely to be observed in ER- than ER+ tumors (OR = 1.18, 95% CI = 1.05-1.31, gene-wide Bonferroni-corrected P = 0.06). In conclusion, specific mTOR pathway genes are potentially important to breast cancer risk and to the ER negativity in African American women. PMID:26577839

  15. Chronic leucine supplementation of a low protein diet increases protein synthesis in skeletal muscle and visceral tissues of neonatal pigs through mTOR signaling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leucine acutely stimulates protein synthesis by activating the mammalian target of rapamycin (mTOR) signaling pathway. We hypothesized that leucine supplementation of a low protein diet will enhance protein synthesis and mTOR signaling in the neonate for prolonged periods. Fasted 5-d-old pigs (n=6–8...

  16. Preventing stroke

    MedlinePlus

    Stroke - prevention; CVA - prevention; cerebral vascular accident - prevention; TIA - prevention, transient ischemic attack - prevention ... Clinical Cardiology; Council on Functional Genomics and ... Council on Hypertension. Guidelines for the primary prevention ...

  17. mTOR plays an important role in cow's milk allergy-associated behavioral and immunological deficits.

    PubMed

    Wu, Jiangbo; de Theije, Caroline G M; da Silva, Sofia Lopes; van der Horst, Hilma; Reinders, Margot T M; Broersen, Laus M; Willemsen, Linette E M; Kas, Martien J H; Garssen, Johan; Kraneveld, Aletta D

    2015-10-01

    Autism spectrum disorder (ASD) is multifactorial, with both genetic as well as environmental factors working in concert to develop the autistic phenotype. Immunological disturbances in autistic individuals have been reported and a role for food allergy has been suggested in ASD. Single gene mutations in mammalian target of rapamycin (mTOR) signaling pathway are associated with the development of ASD and enhanced mTOR signaling plays a central role in directing immune responses towards allergy as well. Therefore, the mTOR pathway may be a pivotal link between the immune disturbances and behavioral deficits observed in ASD. In this study it was investigated whether the mTOR pathway plays a role in food allergy-induced behavioral and immunological deficits. Mice were orally sensitized and challenged with whey protein. Meanwhile, cow's milk allergic (CMA) mice received daily treatment of rapamycin. The validity of the CMA model was confirmed by showing increased allergic immune responses. CMA mice showed reduced social interaction and increased repetitive self-grooming behavior. Enhanced mTORC1 activity was found in the brain and ileum of CMA mice. Inhibition of mTORC1 activity by rapamycin improved the behavioral and immunological deficits of CMA mice. This effect was associated with increase of Treg associated transcription factors in the ileum of CMA mice. These findings indicate that mTOR activation may be central to both the intestinal, immunological, and psychiatric ASD-like symptoms seen in CMA mice. It remains to be investigated whether mTOR can be seen as a therapeutic target in cow's milk allergic children suffering from ASD-like symptoms. PMID:26027949

  18. PPARγ deficiency results in severe, accelerated osteoarthritis associated with aberrant mTOR signalling in the articular cartilage

    PubMed Central

    Vasheghani, Faezeh; Zhang, Yue; Li, Ying-Hua; Blati, Meryem; Fahmi, Hassan; Lussier, Bertrand; Roughley, Peter; Lagares, David; Endisha, Helal; Saffar, Bahareh; Lajeunesse, Daniel; Marshall, Wayne K; Rampersaud, Y Raja; Mahomed, Nizar N; Gandhi, Rajiv; Pelletier, Jean-Pierre; Martel-Pelletier, Johanne; Kapoor, Mohit

    2015-01-01

    Objectives We have previously shown that peroxisome proliferator-activated receptor gamma (PPARγ), a transcription factor, is essential for the normal growth and development of cartilage. In the present study, we created inducible cartilage-specific PPARγ knockout (KO) mice and subjected these mice to the destabilisation of medial meniscus (DMM) model of osteoarthritis (OA) to elucidate the specific in vivo role of PPARγ in OA pathophysiology. We further investigated the downstream PPARγ signalling pathway responsible for maintaining cartilage homeostasis. Methods Inducible cartilage-specific PPARγ KO mice were generated and subjected to DMM model of OA. We also created inducible cartilage-specific PPARγ/mammalian target for rapamycin (mTOR) double KO mice to dissect the PPARγ signalling pathway in OA. Results Compared with control mice, PPARγ KO mice exhibit accelerated OA phenotype with increased cartilage degradation, chondrocyte apoptosis, and the overproduction of OA inflammatory/catabolic factors associated with the increased expression of mTOR and the suppression of key autophagy markers. In vitro rescue experiments using PPARγ expression vector reduced mTOR expression, increased expression of autophagy markers and reduced the expression of OA inflammatory/catabolic factors, thus reversing the phenotype of PPARγ KO mice chondrocytes. To dissect the in vivo role of mTOR pathway in PPARγ signalling, we created and subjected PPARγ-mTOR double KO mice to the OA model to see if the genetic deletion of mTOR in PPARγ KO mice (double KO) can rescue the accelerated OA phenotype observed in PPARγ KO mice. Indeed, PPARγ-mTOR double KO mice exhibit significant protection/reversal from OA phenotype. Significance PPARγ maintains articular cartilage homeostasis, in part, by regulating mTOR pathway. PMID:25573665

  19. Negative regulation of mTOR activity by LKB1-AMPK signaling in non-small cell lung cancer cells

    PubMed Central

    Dong, Li-xia; Sun, Lin-lin; Zhang, Xia; Pan, Li; Lian, Lin-juan; Chen, Zhe; Zhong, Dian-sheng

    2013-01-01

    Aim: To investigate the role of LKB1 in regulation of mTOR signaling in non-small cell lung cancer (NSCLC) cells. Methods: LKB1 protein expression and phosphorylation of AMPK, 4E-BP1 and S6K in the cells were assessed using Western blotting in various NSCLC cell lines (A549, H460, H1792, Calu-1 and H1299). Energy stress was mimicked by treating the cells with 2-deoxyglucose (2-DG). Compound C was used to inhibit AMPK activity. Cell growth was measured using the MTS assay. Results: LKB1 protein was expressed in LKB1 wild-type Calu-1, H1299 and H1792 cells, but it was undetected in LKB1 mutant A549 and H460 cells. Treatment of the LKB1 wild-type cells with 2-DG (5, 10 and 25 mmol/L) augmented the phosphorylation of AMPK in dose- and time-dependent manners. In the LKB1 wild-type cells, 2-DG dramatically suppressed the phosphorylation of two mTOR targets, 4E-BP1 and S6K, whereas the LKB1 mutant A549 and H460 cells were highly resistant to 2-DG-induced inhibition on mTOR activity. In addition, stable knockdown of LKB1 in H1299 cells impaired 2-DG-induced inhibition on mTOR activity. Pretreatment of H1299 and H1792 cells with the AMPK inhibitor compound C (10 μmol/L) blocked 2-DG-induced inhibition on mTOR activity. 2-DG inhibited the growth of H1299 cells more effectively than that of H460 cells; stable knockdown of LKB1 in H1299 cells attenuated the growth inhibition caused by 2-DG. Conclusion: In non-small cell lung cancer cells, LKB1/AMPK signaling negatively regulates mTOR activity and contributes to cell growth inhibition in response to energy stress. PMID:23178462

  20. The PI 3-kinase and mTOR signaling pathways are important modulators of epithelial tubule formation.

    PubMed

    Walid, Shereaf; Eisen, Randi; Ratcliffe, Don R; Dai, Kezhi; Hussain, M Mahmood; Ojakian, George K

    2008-08-01

    Using MDCK cells as a model system, evidence is presented demonstrating that the signaling pathways mammalian target of rapamycin (mTOR) and phosphoinositide 3-kinase (PI 3-kinase) play important roles in the regulation of epithelial tubule formation. Incubation of cells with collagen gel overlays induced early (4-8 h) reorganization of cells (epithelial remodeling) into three-dimensional multicellular tubular structures over 24 h. An MDCK cell line stably expressing the PH domain of Akt, a PI 3-kinase downstream effector, coupled to green fluorescent protein (GFP-Akt-PH) was used to determine the distribution of phosphatidyl inositol-3,4,5-P(3) (PIP(3)), a product of PI 3-kinase. GFP-Akt-PH was associated with lateral membranes in control cells. After incubation with collagen gel overlays, GFP-Akt-PH redistributed into the lamellipodia of migrating cells suggesting that PIP(3) plays a role in epithelial remodeling. Using the small molecule inhibitor LY-294002 that inhibits both mTOR and PI 3-kinase, we demonstrated that kinase activity was required for epithelial remodeling, disruption of cell junctions and subsequent modulation of tubule formation. Since the mTOR signaling pathway is downstream of PI 3-kinase, the effects of rapamycin, a specific mTOR inhibitor, on tubule formation were assessed. Rapamycin did not affect epithelial remodeling or GFP-Akt-PH redistribution but inhibited elongated tubule formation that occurred later (24 h) in morphogenesis. These results were further supported by using RNA interference to down-regulate mTOR and inhibit tubule formation. Our studies demonstrate that PI 3-kinase regulates early epithelial remodeling stages while mTOR modulates latter stages of tubule development. PMID:18366086

  1. Subependymal giant cell astrocytoma: a lesion with activated mTOR pathway and constant expression of glutamine synthetase.

    PubMed

    Buccoliero, Anna Maria; Caporalini, Chiara; Giordano, Flavio; Mussa, Federico; Scagnet, Mirko; Moscardi, Selene; Baroni, Gianna; Genitori, Lorenzo; Taddei, Gian Luigi

    2016-01-01

    Subependymal giant-cell astrocytoma (SEGA) is a rare tumor associated with tuberous sclerosis complex (TSC). TSC mainly involves the central nervous system (CNS) where SEGA, subependymal nodules, and cortical tubers may be present. First studies suggested the astrocytic nature of SEGA while successive studies demonstrated the mixed glio-neuronal nature. There are similarities between TSC-associated CNS lesions and type IIb focal cortical dysplasia (FCD). In all these pathologies, mammalian target of rapamycin (mTOR) pathway activation has been demonstrated. Recent data evidenced that balloon cells in FCD IIb express glutamine synthetase (GS). GS is involved in the clearance of glutamate. Cells expressing GS might exert an antiepileptic role. We evaluated by immunohistochemistry the glial fibrillary acidic protein (GFAP), neurofilaments (NF), and GS expression and the mTOR status (mTOR and phosphorylated ribosomal protein S6) in 16 SEGAs and 2 cortical tubers. Our purpose was to emphasize the mixed nature of SEGA and to further investigate the similarities between TSC-related CNS lesions (in particular SEGA) and FCD IIb. We confirm the glio-neuronal nature and the common activation of the mTOR pathway in SEGAs. In addition, we report for the first time that these tumors, analogously to FCD IIb, commonly express GS. Notably, the expression of mTOR, phosphorylated ribosomal protein S6, and GS was restricted to gemistocytic-like GFAP-negative cells. GS expression and mTOR pathway activation were also documented in cortical tubers. Further studies are necessary to understand the significance of GS expression in SEGAs as well as in cortical tubers. PMID:27390104

  2. Preclinical trial of a new dual mTOR inhibitor, MLN0128, using renal cell carcinoma tumorgrafts

    PubMed Central

    Ingels, Alexandre; Zhao, Hongjuan; Thong, Alan E.; Saar, Matthias; Valta, Maija P.; Nolley, Rosalie; Santos, Jennifer; Peehl, Donna M.

    2015-01-01

    mTOR is a rational target in renal cell carcinoma (RCC) because of its role in disease progression. However, the effects of temsirolimus, the only first-generation mTOR inhibitor approved by the FDA for first-line treatment of metastatic RCC, on tumor reduction and progression-free survival are minimal. Second-generation mTOR inhibitors have not been evaluated on RCC. We compared the effects of temsirolimus and MLN0128, a potent second-generation mTOR inhibitor, on RCC growth and metastasis using a realistic patient-derived tissue slice graft (TSG) model. TSGs were derived from three fresh primary RCC specimens by subrenal implantation of precision-cut tissue slices into immunodeficient mice that were randomized and treated with MLN0128, temsirolimus, or placebo. MLN0128 consistently suppressed primary RCC growth, monitored by magnetic resonance imaging (MRI), in three TSG cohorts for up to 2 months. Temsirolimus, in contrast, only transiently inhibited the growth of TSGs in one of two cohorts before resistance developed. In addition, MLN0128 reduced liver metastases, determined by human-specific quantitative polymerase chain reaction, in two TSG cohorts, whereas temsirolimus failed to have any significant impact. Moreover, MLN0128 decreased levels of key components of the two mTOR subpathways including TORC1 targets 4EBP1, p-S6K1, HIF1α and MTA1 and the TORC2 target c-Myc, consistent with dual inhibition. Our results demonstrated that MLN0128 is superior to temsirolimus in inhibiting primary RCC growth as well as metastases, lending strong support for further clinical development of dual mTOR inhibitors for RCC treatment. PMID:24243565

  3. MicroRNA-224 aggrevates tumor growth and progression by targeting mTOR in gastric cancer.

    PubMed

    Zhang, Ying; Li, Chang-Feng; Ma, Lian-Jun; Ding, Meng; Zhang, Bin

    2016-09-01

    Growing evidence suggests that microRNA plays an essential role in the development and metastasis of many tumors, including gastric cancer. Aberrant miR-224 expression has been indicated in tumor growth, the mechanism of miR-224 promoting the proliferation and metastatic ability for gastric cancer remains unclear. Accumulating evidence reports that mTOR signal pathway plays an important role in the cellular process, such as apoptosis, cell growth and proliferation. The goal of the present study was to identify whether miR-224 could inhibit the growth, migration, invasion, proliferation and metastasis of gastric cancer through targeting mTOR expression. Real-time PCR (RT-PCR) was used to quantify miR-224 expression in vitro and in vivo experiments. Luciferase reporter assays were performed to confirm the activity of mTOR pathway, and immunofluorescence staining assay was conducted to observe apoptosis and cell proliferation ability. Bioinformatics as well as cell luciferase function studies distinguished the direct modulation of miR-224 on the 3'-UTR of the