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

Several novel therapies have been approved recently in advanced renal cell carcinoma (RCC). These agents inhibit pathways downstream of loss of the von Hippel-Lindau gene VHL. They target the vascular endothelial growth factor (VEGF) ligand, VEGF receptor (VEGFR), mammalian target of rapamycin (mTOR), and other potentially important pathways. Even with improvements in survival, disease progresses in all patients. There is a critical need to increase complete responses (now rare). One such strategy is combining several agents to block different levels of the VEGF-VEGFR axis (vertical blockade). Alternatively, combination of a VEGF-VEGFR inhibitor with an mTOR inhibitor is attractive. Finally, horizontal blockade of VEGFR with epidermal growth factor receptor and/or platelet-derived growth factor receptor, all signaling pathways activated by hypoxia-inducible factor, is another approach. Already trials have revealed difficulties with combination therapy. By combining agents, the toxicity of 1 or both can be enhanced. The authors of this article report their experience with sorafenib plus bevacizumab, which produced increases in hand-foot syndrome, hypertension, and proteinuria, all known toxic effects. Clinical activity was impressive with 25 responses in 48 patients (52% response rate). Other combinations also required dose reductions (sorafenib with temsirolimus) or were intolerable (sunitinib with temsirolimus or sunitinib with bevacizumab). Unexpected toxicity characterized by microangiopathic hemolytic anemia occurred late in treatment with sunitinib and bevacizumab. Toxicity may be more severe in patients with RCC, who frequently have 1 kidney and poor renal function. Once tolerability for combination regimens has been established, it will be critical to design informative phase 2 trials and address the benefit of combination versus sequential therapy.
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PMID:Combination targeted therapy in advanced renal cell carcinoma. 1940 58

The role of altered mitochondria function has recently emerged as an important mechanism for the development of diabetic complications. Altered mitochondria function has also been implicated in the ageing process, defective insulin secretion, hypertension, arteriosclerosis, ischemia-reperfusion injury and apoptosis. Normally, the mitochondria are associated with ATP production using primarily pyruvate as the substrate, but recent reports indicate that tissue specific preferences exist. Also, the mitochondria are a substantial source of superoxide production, preferentially during states of elevated intracellular glucose concentrations. The mitochondria function is regulated by several factors including nitric oxide, oxidative stress, mammalian target of rapamycin, ADP and P(i) availability, which result in a complex regulation of ATP production and oxygen consumption, but also superoxide generation. These factors seem to be tissue specific, which warrants a more diverse mechanistic model applying to that specific tissue or cell type. This review presents the basic functions of the mitochondria and focuses on the complex interplay between oxidative stress, nitric oxide and uncoupling proteins in regulating mitochondria function with special focus on diabetes-induced alterations occurring on the mitochondria level.
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PMID:Diabetes, oxidative stress, nitric oxide and mitochondria function. 1944 97

VEGF and mTOR inhibitors have encouraging clinical activity for patients with advanced renal cell carcinoma (RCC), but may lead to significant short- and long-term toxicities. Although 40-70% of adverse events (AEs) are grade 1 and 2, 10-20% of patients develop grade 3 or 4 AEs requiring dose reductions, drug holidays or treatment discontinuation. The long-term impact of the most common grade 3 and 4 AEs observed in Phase III trials evaluating VEGF and mTOR inhibitors, including hypertension, decreased left ventricular ejection fraction, hand-foot-syndrome and myelosuppression, are a concern in RCC patients who are living longer and receiving chronic sequential or combination therapy. There is a clear need to develop a more rational way to individualize therapy for RCC. Long-term follow-up from existing Phase II/III trials should provide us with increased understanding of the potential implications of AEs in RCC patients. Prevention, early recognition and aggressive management of side effects are fundamental to avoid significant long-term complications and unnecessary dose reductions, which can ultimately reduce the efficacy of these novel agents.
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PMID:Toxicity associated with the long-term use of targeted therapies in patients with advanced renal cell carcinoma. 1949 16

The cumulative incidence of chronic kidney disease after liver transplantation (LT) is on the order of 40 to 50% at 1 year and over 50% at 5 years, and that of pre-end-stage renal failure 5-10% at 1 year and 10-20% at 5 and 10 years. Several variables appear to be independently associated with onset of kidney failure: age, sex (male), ethnicity (non-Asian), low glomerular filtration rate (GFR) before transplantation, use of renal replacement therapy before LT, diabetes before LT, HCV carriage, postoperative onset of acute renal failure, the year of transplantation (before or after 1994). Various factors cause chronic kidney disease after LT. Calcineurin inhibitors, specifically cyclosporine and tacrolimus, but also diabetes, nephroangiosclerosis, previous use of hydroxyethylstarch, play a major role in the onset of postgraft kidney failure. It is generally agreed that the nephrotoxicity of calcineurin inhibitors is in part dose-dependent and that a reduction in the dose can improve renal function. Nonetheless, the lesions are in large part irreversible. Trials are required to test interventions early after the LT, as soon as the first signs of kidney failure appear. Moreover, although the effect is dose-dependent, the relation with blood concentration of the drug is very imperfect, so any intervention must reduce the dose and not just the concentration to improve renal function. The introduction of new immunosuppressive drugs that are not nephrotoxic, such as mycophenolate mofetil, mTOR inhibitors, and anti-CD25 monoclonal antibodies [basiliximab and daclizumab (withdrawn from the market)], allow primary or secondary prevention of nephrotoxicity, with a partial or complete reduction in calcineurin inhibitors. Other interventions useful to limiting kidney failure after LT are the correction of hypertension, diabetes, and hyperlipidemia.
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PMID:[Renal failure following liver transplantation]. 1956 Aug 96

Lipid abnormalities are a common complication of kidney transplantation, occurring in up to 60% of patients. In fact, impairment of lipid metabolism is often present before renal transplantation due to the uremic state. After transplantation and recovery of renal function, lipid disturbances usually persist but show a different profile due to the various effects of immunosuppressive drugs on lipid metabolism. Actually, steroids, calcineurin inhibitors, and mammalian target of rapamycin inhibitors usually lead to quantitative and qualitative abnormalities of very low-density, low-density, and high-density lipoproteins. As cardiovascular diseases remain the leading cause of death in renal transplant recipients, management of dyslipidemia and other traditional risk factors, such as smoking, arterial hypertension, diabetes mellitus, and obesity, is of great importance to prevent cardiovascular complications and chronic allograft dysfunction. This review addresses the causes of dyslipidemia, the role of immunosuppressive drugs, and current recommendations to manage lipid disorders in renal transplant recipients.
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PMID:Dyslipidemia following kidney transplantation: diagnosis and treatment. 1964 Mar 44

Compelling evidence is accumulating indicating a pathophysiological role of the serum-and-glucocorticoid-inducible-kinase-1 (SGK1) in the development and complications of diabetes. SGK1 is ubiquitously expressed with exquisitely high transcriptional volatility. Stimulators of SGK1 expression include hyperglycemia, cell shrinkage, ischemia, glucocorticoids and mineralocorticoids. SGK1 is activated by insulin and growth factors via PI3K, 3-phosphoinositide dependent kinase PDK1 and mTOR. SGK1 activates ion channels (including ENaC, TRPV5, ROMK, KCNE1/KCNQ1 and CLCKa/Barttin), carriers (including NCC, NKCC, NHE3, SGLT1 and EAAT3), and the Na(+)/K(+)-ATPase. It regulates the activity of several enzymes (e.g., glycogen-synthase-kinase-3, ubiquitin-ligase Nedd4-2, phosphomannose-mutase-2), and transcription factors (e.g., forkhead-transcription-factor FOXO3a, beta-catenin and NF-kappaB). A common SGK1 gene variant ( approximately 3 - 5% prevalence in Caucasians, approximately 10% in Africans) is associated with increased blood pressure, obesity and type 2 diabetes. In patients suffering from type 2 diabetes, SGK1 presumably contributes to fluid retention and hypertension, enhanced coagulation and increased deposition of matrix proteins leading to tissue fibrosis such as diabetic nephropathy. Accordingly, targeting SGK1 may favourably influence occurrence and course of type 2 diabetes.
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PMID:Targeting SGK1 in diabetes. 1976 91

Evidence exists that protein kinase C and the mammalian target of rapamycin are important regulators of cardiac hypertrophy. We examined the contribution of these signaling kinases to cardiac growth in spontaneously hypertensive rats (SHRs). Systolic blood pressure was increased (P<0.001) at 10 weeks in SHRs versus Wistar-Kyoto controls (162+/-3 versus 128+/-1 mm Hg) and was further elevated (P<0.001) at 17 weeks in SHRs (184+/-7 mm Hg). Heart:body weight ratio was not different between groups at 10 weeks but was 22% greater (P<0.01) in SHRs versus Wistar-Kyoto controls at 17 weeks. At 10 weeks, activation of Akt and S6 ribosomal protein was greater (P<0.01) in SHRs but returned to normal by 17 weeks. In contrast, SHRs had protein kinase C activation only at 17 weeks. To determine whether mammalian target of rapamycin regulates the initial development of hypertrophy, rats were treated with rapamycin (2 mg/kg per day IP) or saline vehicle from 13 to 16 weeks of age. Rapamycin inhibited cardiac mammalian target of rapamycin in SHRs, as evidenced by reductions (P<0.001) in phosphorylation of S6 ribosomal protein and eukaryotic translation initiation factor-4E binding protein 1. Rapamycin treatment also reduced (P<0.001) heart weight and hypertrophy by 47% and 53%, respectively, in SHRs in spite of increased (P<0.001) systolic blood pressure versus untreated SHRs (213+/-8 versus 189+/-6 mm Hg). Atrial natriuretic peptide, brain natriuretic peptide, and cardiac function were unchanged between SHRs treated with rapamycin or vehicle. These data show that mammalian target of rapamycin is required for the development of cardiac hypertrophy evoked by rising blood pressure in SHRs.
Hypertension 2009 Dec
PMID:Mammalian target of rapamycin is a critical regulator of cardiac hypertrophy in spontaneously hypertensive rats. 1988 61

The plethora of novel agents recently approved for the management of metastatic renal cell carcinoma (RCC) has changed the therapeutic landscape in this disease. The plethora of targets some of these agents inhibit can result in a wide range of side effects. While these novel therapies can be viewed as inhibitors of angiogenesis that directly or indirectly target the vascular endothelial growth factor (VEGF) pathway, their individual mechanisms of action (MoA) are key to defining their side-effect profiles. Direct VEGF inhibition with the anti-VEGF monoclonal antibody bevacizumab, is primarily associated with side effects related to the precise inhibition of VEGF, such as proteinuria, hypertension and minor bleeding events. In contrast, non-VEGF-related side effects are observed with agents inhibiting multiple receptor tyrosine kinases (sunitinib, sorafenib, axitinib and pazopanib) and mammalian target of rapamycin inhibitors (temsirolimus and everolimus); these include diarrhoea, skin rash, stomatitis, hand-foot skin reaction, hypothyroidism, and haematological and metabolic abnormalities. This review discusses the MoA of these novel therapies and how a greater understanding of MoA may help to predict the range and type of side effects, develop combinations of agents with acceptable tolerability, enable a more rational approach to patient selection, and allow the development of effective side-effect management strategies.
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PMID:Plethora of agents, plethora of targets, plethora of side effects in metastatic renal cell carcinoma. 2016 17

Autosomal dominant polycystic kidney disease (ADPKD) is a commonly inherited renal disorder caused by defects in the PKD1 or PKD2 genes. ADPKD is associated with significant morbidity, and is a major underlying cause of end-stage renal failure (ESRF). Commonly, treatment options are limited to the management of hypertension, cardiovascular risk factors, dialysis, and transplantation when ESRF develops, although several new pharmacotherapies, including rapamycin, have shown early promise in animal and human studies. Evidence implicates polycystin-1 (PC-1), the gene product of the PKD1 gene, in regulation of the mTOR pathway. Here we demonstrate a mechanism by which the intracellular, carboxy-terminal tail of polycystin-1 (CP1) regulates mTOR signaling by altering the subcellular localization of the tuberous sclerosis complex 2 (TSC2) tumor suppressor, a gatekeeper for mTOR activity. Phosphorylation of TSC2 at S939 by AKT causes partitioning of TSC2 away from the membrane, its GAP target Rheb, and its activating partner TSC1 to the cytosol via 14-3-3 protein binding. We found that TSC2 and a C-terminal polycystin-1 peptide (CP1) directly interact and that a membrane-tethered CP1 protects TSC2 from AKT phosphorylation at S939, retaining TSC2 at the membrane to inhibit the mTOR pathway. CP1 decreased binding of 14-3-3 proteins to TSC2 and increased the interaction between TSC2 and its activating partner TSC1. Interestingly, while membrane tethering of CP1 was required to activate TSC2 and repress mTOR, the ability of CP1 to inhibit mTOR signaling did not require primary cilia and was independent of AMPK activation. These data identify a unique mechanism for modulation of TSC2 repression of mTOR signaling via membrane retention of this tumor suppressor, and identify PC-1 as a regulator of this downstream component of the PI3K signaling cascade.
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PMID:Carboxy terminal tail of polycystin-1 regulates localization of TSC2 to repress mTOR. 2016 78

Tuberous sclerosis, caused by germline mutations in the TSC1 or TSC2 genes, is associated with aberrant upregulation of the mammalian target of rapamycin (mTOR) signalling pathway, resulting in growth of tumours, including renal angiomyolipomas (AMLs). AMLs may cause hypertension, renal failure and spontaneous life-threatening haemorrhage. Previously, invasive interventions were required to treat AMLs. More recently, mTOR inhibitors have been used as molecularly targeted treatment to treat AMLs. We present here the case of a paediatric patient with TSC in whom sirolimus has been used successfully to halt growth of renal AMLs.
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PMID:Sirolimus and tuberous sclerosis-associated renal angiomyolipomas. 2045 4


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