Mechanistic target of rapamycin inhibitors in solid organ transplantation: from benchside to clinical use

A cocktail of rapamycin, acarbose, and phenylbutyrate prevents age-related cognitive decline in mice by targeting multiple aging pathways

Aging is a primary risk factor for cognitive impairment and exacerbates multiple biological processes in the brain, including but not limited to nutrient sensing, insulin signaling, and histone deacetylation activity. Therefore, a pharmaceutical intervention of aging that targets distinct but overlapping pathways provides a basis for testing combinations of drugs as a cocktail. Our previous study showed that middle-aged mice treated with a cocktail of rapamycin, acarbose, and phenylbutyrate for 3 months had increased resilience to age-related cognitive decline. This finding provided the rationale to investigate the transcriptomic and molecular changes within the brains of mice that received this cocktail treatment or control treatment. Transcriptomic profiles were generated through ribonucleic acid (RNA) sequencing, and pathway analysis was performed by gene set enrichment analysis to evaluate the overall RNA message effect of the drug cocktail. Molecular endpoints representing aging pathways were measured using immunohistochemistry to further validate the attenuation of brain aging in the hippocampus of mice that received the cocktail treatment, each individual drug or control. Results showed that biological processes that enhance aging were suppressed, with an increased trend of autophagy in the brains of mice given the drug cocktail. The molecular endpoint assessments indicated that treatment with the drug cocktail was overall more effective than any of the individual drugs for relieving cognitive impairment by targeting multiple aging pathways.

Short term treatment with a cocktail of rapamycin, acarbose and phenylbutyrate delays aging phenotypes in mice

Pharmaceutical intervention of aging requires targeting multiple pathways, thus there is rationale to test combinations of drugs targeting different but overlapping processes. In order to determine if combining drugs shown to extend lifespan and healthy aging in mice would have greater impact than any individual drug, a cocktail diet containing 14 ppm rapamycin, 1000 ppm acarbose, and 1000 ppm phenylbutyrate was fed to 20-month-old C57BL/6 and HET3 4-way cross mice of both sexes for three months. Mice treated with the cocktail showed a sex and strain-dependent phenotype consistent with healthy aging including decreased body fat, improved cognition, increased strength and endurance, and decreased age-related pathology compared to mice treated with individual drugs or control. The severity of age-related lesions in heart, lungs, liver, and kidney was consistently decreased in mice treated with the cocktail compared to mice treated with individual drugs or control, suggesting an interactive advantage of the three drugs. This study shows that a combination of three drugs, each previously shown to enhance lifespan and health span in mice, is able to delay aging phenotypes in middle-aged mice more effectively than any individual drug in the cocktail over a 3-month treatment period.

Clinical parameters and biomarkers predicting spontaneous operational tolerance after liver transplantation: a scoping review protocol

Objective: This scoping review aims at systematically mapping reported prognostic factors for spontaneous immunosuppression (IS) free allograft tolerance (operational tolerance, OT) in non-viral hepatitis and non-autoimmune disease liver transplant (LT) recipients who are undergoing immunosuppression withdrawal (ISW). The results may inform the subsequent conduct of a systematic review with a more specific review question.

Background: LT is currently the most effective treatment for end-stage liver diseases. Whereas the short-term outcomes after LT have dramatically improved over the last decades, the long-term outcomes remain unsatisfactory, mainly because of side effects of lifelong IS, such as infections, cardiovascular diseases, malignancies, and nephrotoxicity. ISW studies have shown that OT can be achieved by a subset of LT recipients and recent research has identified biomarkers of OT in these patients. However, an evidence-based selection algorithm for patients that can predictably benefit from ISW is not available to date. The planned review will, therefore, map existing knowledge on prognostic clinical parameters and biomarkers for OT.

Inclusion criteria: We will consider studies that record any clinical parameter or biomarker before the initiation of ISW in paediatric or adult non-viral hepatitis and non-autoimmune disease LT recipients and analyse their possible association with ISW outcomes (OT or non-tolerance). Studies addressing the effectiveness of OT-inducing treatments will be excluded.

Methods: Embase, MEDLINE, and Cochrane Library will be searched for relevant articles or conference abstracts. Full-texts of selected abstracts will be independently screened for inclusion by two reviewers. References and citing articles of included records will be screened for additional relevant records. Clinical trial registries will be searched for ongoing studies, and their investigators contacted for the sharing of unpublished data. Data from included records will be independently extracted by two reviewers using a prespecified data extraction table and presented in both tabular and narrative form.

Clinical parameters and biomarkers predicting spontaneous operational tolerance after liver transplantation: a scoping review protocol

Objective: This scoping review aims at systematically mapping reported prognostic factors for spontaneous immunosuppression (IS) free allograft tolerance (operational tolerance, OT) in non-viral hepatitis and non-autoimmune disease liver transplant (LT) recipients who are undergoing immunosuppression withdrawal (ISW). The results may inform the subsequent conduct of a systematic review with a more specific review question. Background: LT is currently the most effective treatment for end-stage liver diseases. Whereas the short-term outcomes after LT have dramatically improved over the last decades, the long-term outcomes remain unsatisfactory, mainly because of side effects of lifelong IS, such as infections, cardiovascular diseases, malignancies, and nephrotoxicity. ISW studies have shown that OT can be achieved by a subset of LT recipients and recent research has identified biomarkers of OT in these patients. However, an evidence-based selection algorithm for patients that can predictably benefit from ISW is not available to date. The planned review will, therefore, map existing knowledge on prognostic clinical parameters and biomarkers for OT. Inclusion criteria: We will consider studies that record any clinical parameter or biomarker before the initiation of ISW in paediatric or adult non-viral hepatitis and non-autoimmune disease LT recipients and analyse their possible association with ISW outcomes (OT or non-tolerance). Studies addressing the effectiveness of OT-inducing treatments will be excluded. Methods: Embase, MEDLINE, and Cochrane Library will be searched for relevant articles or conference abstracts. Full-texts of selected abstracts will be independently screened for inclusion by two reviewers. References and citing articles of included records will be screened for additional relevant records. Clinical trial registries will be searched for ongoing studies, and their investigators contacted for the sharing of unpublished data. Data from included records will be independently extracted by two reviewers using a prespecified data extraction table and presented in both tabular and narrative form.

Novel cancer therapies and their association with diabetes

Over the last decade, there has been a shift in the focus of cancer therapy from conventional cytotoxic drugs to therapies more specifically directed to cancer cells. These novel therapies include immunotherapy, targeted therapy and precision medicine, each developed in great part with a goal of limiting collateral destruction of normal tissues, while enhancing tumor destruction. Although this approach is sound in theory, even new, specific therapies have some undesirable, 'off target effects', in great part due to molecular pathways shared by neoplastic and normal cells. One such undesirable effect is hyperglycemia, which results from either the loss of immune tolerance and autoimmune destruction of pancreatic β-cells or dysregulation of the insulin signaling pathway resulting in insulin resistance. These distinct pathogenic mechanisms lead to clinical presentations similar to type 1 (T1DM) and type 2 (T2DM) diabetes mellitus. Both types of diabetes have been reported in patients across clinical trials, and data on the mechanism(s) for developing hyperglycemia, prevalence, prognosis and effect on cancer mortality is still emerging. With the rapidly expanding list of clinical indications for new cancer therapies, it is essential to understand the impact of their adverse effects. In this review, we focus on hyperglycemia and diabetes related to cancer therapies, describe what is known about mechanism(s) leading to dysregulated glucose metabolism and provide a guide to management of complex oncology patients with a new diagnosis of diabetes.

Targeting Strategies for Glucose Metabolic Pathways and T Cells in Colorectal Cancer

Colorectal cancer is a heterogeneous group of diseases that result from the accumulation of different sets of genomic alterations, together with epigenomic alterations, and it is influenced by tumor-host interactions, leading to tumor cell growth and glycolytic imbalances. This review summarizes recent findings that involve multiple signaling molecules and downstream genes in the dysregulated glycolytic pathway. This paper further discusses the role of the dysregulated glycolytic pathway in the tumor initiation, progression and the concomitant systemic immunosuppression commonly observed in colorectal cancer patients. Moreover, the relationship between colorectal cancer cells and T cells, especially CD8+ T cells, is discussed, while different aspects of metabolic pathway regulation in cancer cell proliferation are comprehensively defined. Furthermore, this study elaborates on metabolism in colorectal cancer, specifically key metabolic modulators together with regulators, glycolytic enzymes, and glucose deprivation induced by tumor cells and how they inhibit T-cell glycolysis and immunogenic functions. Moreover, metabolic pathways that are integral to T cell function, differentiation, and activation are described. Selective metabolic inhibitors or immunemodulation agents targeting these pathways may be clinically useful to increase effector T cell responses for colorectal cancer treatment. However, there is a need to identify specific antigens using a cancer patient-personalized approach and combination strategies with other therapeutic agents to effectively target tumor metabolic pathways.

Evaluation of the 1000 renal transplants carried out at the University Hospital of the Botucatu Medical School (HCFMB) - UNESP and their evolution over the years

INTRODUCTION

The progress in kidney transplantation has been evident over the years, as well as its benefits for patients.

OBJECTIVES

To evaluate the 1.000 kidney transplants performed at the Botucatu Medical School University Hospital, subdividing the patients in different periods, according to the current immunosuppression, and evaluating the differences in graft and patient survival.

METHODS

Retrospective cohort analysis of the transplants performed between 06/17/87 to 07/31/16, totaling 1,046 transplants, subdivided into four different periods: 1) 1987 to 2000: cyclosporine with azathioprine; 2) 2001 to 2006: cyclosporine with mycophenolate; 3) 2007 to 2014: tacrolimus with antimetabolic; and 4) 2015 to 2016: tacrolimus with antimetabolic, with increased use of the combination of tacrolimus and mTOR inhibitors.

RESULTS

There was an increase in the mean age of recipients and increase in deceased donors and their age in the last two periods. There was a reduction in graft function delay, being 54.3% in the fourth period, compared to 78.8% in the first, p = 0.002. We found a reduction in acute rejection, being 6.1% in the last period compared to 36.3% in the first, p = 0.001. Urological complications and diabetes after transplantation were more frequent in the first two periods. The rates of cytomegalovirus infection were higher in the last two periods. There was an improvement in graft survival, p = 0.003. There was no difference in patient survival, p = 0.77 (Figure 2).

CONCLUSION

There was a significant increase in the number of transplants, with evolution in graft survival, despite the worsening in the profiles of recipients and donors.

Everolimus as cancer therapy: Cardiotoxic or an unexpected antiatherogenic agent? A narrative review

Everolimus (EVE) is now approved by many agencies for the treatment of variable neoplasms. The risk for adverse events with this agent is not adequately defined. The purpose of this review is to summarize the EVE-induced cardiotoxic effect as an antineoplastic factor on patients who received the specific drug and to evaluate any possible antiatherogenic effects due to systemic use of the drug. Articles were searched on PubMed until August 2017. Articles included an expanded-access clinical trial, as well as phase 2 or 3 clinical trials (most of them were randomized). Three experimental studies that provided evidence for the possible antiatherogenic action of EVE were also included. In addition, only studies that evaluated the systemic use of the drug were included. To be eligible for inclusion, trials should have evaluated patients with malignancy, treated by EVE, or assessed the antiatherogenic effect of the systemic use of EVE through clinical or experimental studies. Only articles written in English language were included. No direct cardiotoxic adverse effects (arrhythmia, acute coronary event, heart failure, and echocardiography pathologic findings) were reported. Patients appeared to have a risk of developing adverse events that could be associated with the risk factors of cardiovascular disease. In all clinical studies, patients suffered hyperglycemia, and in most of them, hyperlipidemia was observed. Fewer studies have reported the incidence of hypertension. Finally, there is evidence claiming that EVE has an antiatherogenic action. Three experimental studies have shown that the systemic use of EVE in mice or rabbits with atherosclerotic lesions led to the reduction in atheromatous plaque growth. However, we could not find any clinical study that showed similar results in patients with cancer. To sum up, the only reported cardiac adverse event of EVE treatment in patients with cancer is indirect. They are associated with the risk factors of cardiovascular disease (hyperglycemia, hyperlipidemia, and hypertension), which are mainly mild and easily manageable. Further research and data that support the antiatherogenic action of EVE are needed.

Autophagy upregulates (pro)renin receptor expression via reduction of P62/SQSTM1 and activation of ERK1/2 signaling pathway in podocytes

Autophagy plays a major role in podocytes health and disease. P62, also known as sequestosome-1 (SQSTM1), is a marker for autophagic activity and is required for the formation and degradation of ubiquitnated protein by autophagy. Knockout of p62 enhanced extracellular signal-regulated kinases (ERK1/2) activity. (pro)renin receptor (PRR) is expressed in podocytes where it contributes to the homeostasis of these cells. The influence of autophagy on PRR expression is unknown. We hypothesized that in podocytes, upregulation of autophagic activity increases PRR expression via reduction of p62 and stimulation of ERK1/2 signaling pathway. Cultured mouse podocytes were treated with the autophagy activators, rapamycin or Earle's balanced salt solution (EBSS), for 48 h. Both rapamycin and EBSS significantly decreased p62 protein levels, increased ERK1/2 activation by phosphorylating pTpY185/187, and increased mRNA and protein expressions of PRR. Utilizing confocal microscopy demonstrated that rapamycin and EBSS significantly decreased p62/SQSTM1 and increased PRR protein expressions. Similarly, by enhancing autophagic activity by transfection with autophagy-related 5 (ATG5) cDNA or ATG7 cDNA, results similar to those observed with rapamycin and EBSS treatments were produced. Inhibition of autophagic flux with bafilomycin A1 reversed the effects of rapamycin. ERK1/2 inhibitor U0126 significantly attenuated mRNA and protein expressions of PRR in podocytes treated with rapamycin. In conclusion, upregulation of autophagy enhanced PRR expression through reduction of p62 and stimulation of ERK1/2 activity signaling pathway.

Encapsulating an Immunosuppressant Enhances Tolerance Induction by Siglec-Engaging Tolerogenic Liposomes

Unwanted antibody responses significantly impact human health, and current options for treating deleterious antibody responses largely rely on broad immunosuppressants that can compromise overall immunity. A desirable alternative is to induce antigen-specific immune tolerance. We have shown that co-presentation of antigen and ligands of B cell sialic acid-binding immunoglobulin-like lectins (Siglecs) on a liposomal nanoparticle induces antigen-specific tolerance. Although Siglec-engaging tolerance-inducing antigenic liposomes (STALs) induce robust B cell tolerance in naïve mice, the full potential of STALs requires long-term tolerance induction and suppression of an ongoing immune response. We hypothesized that STALs encapsulated with rapamycin (RAPA), an immunomodulator, could improve the efficacy of STALs and potentially enable their use in the context of immunological memory. Here, we showed that formulation of STALs with RAPA produced enhanced tolerance induction in naïve mice compared to STALs without RAPA but had minimal impact on inducing tolerance in previously sensitized mice. These findings indicate that the addition of immunomodulators to STALs could be beneficial in tolerance induction and support future development of STALs for the treatment of allergy and autoimmune diseases.

Vascular hyperpermeability as a hallmark of phacomatoses: is the etiology angiogenesis related to or comparable with mechanisms seen in inflammatory pathways? Part II: angiogenesis- and inflammation-related molecular pathways, tumor-associated macrophages, and possible therapeutic implications: a comprehensive review

Phacomatoses are a special group of familial hamartomatous syndromes with unique neurocutaneous manifestations as well as characteristic tumors. Neurofibromatosis type 2 (NF2) and tuberous sclerosis complex (TSC) are representatives of this family. A vestibular schwannoma (VS) and subependymal giant cell tumor (SGCT) are two of the most common intracranial tumors associated with these syndromes, related to NF2 and TSC, respectively. These tumors can present with an obstructive hydrocephalus due to their location adjacent to or in the ventricles. Remarkably, both tumors are also known to have a unique association with elevated protein concentrations in the cerebrospinal fluid (CSF), sometimes in association with a non-obstructive (communicating) hydrocephalus. Of the two, SGCT has been shown to be associated with a predisposition to CSF clotting, causing a debilitating recurrent shunt obstruction. However, the exact relationship between high protein levels and clotting of CSF remains unclear, nor do we understand the precise mechanism of CSF clotting observed in SGCT. Elevated protein levels in the CSF are thought to be caused by increased vascular permeability and dysregulation of the blood-brain barrier. The two presumed underlying pathophysiological processes for that in the context of tumorigenesis are angiogenesis and inflammation. Both these processes are correlated to the phosphatidylinositol-3-kinase/Akt/mammalian target of rapamycin pathway which is tumorigenesis related in many neoplasms and nearly all phacomatoses. In this review, we discuss the influence of angiogenesis and inflammation pathways on vascular permeability in VSs and SGCTs at the phenotypic level as well as their possible genetic and molecular determinants. Part I described the historical perspectives and clinical aspects of the relationship between vascular permeability, abnormal CSF protein levels, clotting of the CSF, and communicating hydrocephalus. Part II hereafter describes the different cellular and molecular pathways involved in angiogenesis and inflammation observed in both tumors and explores the existing metabolic overlap between inflammation and coagulation. Interestingly, while increased angiogenesis can be observed in both tumors, inflammatory processes seem significantly more prominent in SGCT. Both SGCT and VS are characterized by different subgroups of tumor-associated macrophages (TAMs): the pro-inflammatory M1 type is predominating in SGCTs, while the pro-angiogenetic M2 type is predominating in VSs. We suggest that a lack of NF2 protein in VS and a lack of TSC1/TSC2 proteins in SGCT significantly influence this fundamental difference between the two tumor types by changing the dominant TAM type. Since inflammatory reactions and coagulation processes are tightly connected, the pro-inflammatory state of SGCT may also explain the associated tendency for CSF clotting. The underlying cellular and molecular differences observed can potentially serve as an access point for direct therapeutic interventions for tumors that are specific to certain phacomatoses or others that also carry such genetic changes.

The Complexity of Targeting PI3K-Akt-mTOR Signalling in Human Acute Myeloid Leukaemia: The Importance of Leukemic Cell Heterogeneity, Neighbouring Mesenchymal Stem Cells and Immunocompetent Cells

Therapeutic targeting of PI3K-Akt-mTOR is considered a possible strategy in human acute myeloid leukaemia (AML); the most important rationale being the proapoptotic and antiproliferative effects of direct PI3K/mTOR inhibition observed in experimental studies of human AML cells. However, AML is a heterogeneous disease and these effects caused by direct pathway inhibition in the leukemic cells are observed only for a subset of patients. Furthermore, the final effect of PI3K-Akt-mTOR inhibition is modulated by indirect effects, i.e., treatment effects on AML-supporting non-leukemic bone marrow cells. In this article we focus on the effects of this treatment on mesenchymal stem cells (MSCs) and monocytes/macrophages; both these cell types are parts of the haematopoietic stem cell niches in the bone marrow. MSCs have unique membrane molecule and constitutive cytokine release profiles, and mediate their support through bidirectional crosstalk involving both cell-cell contact and the local cytokine network. It is not known how various forms of PI3K-Akt-mTOR targeting alter the molecular mechanisms of this crosstalk. The effect on monocytes/macrophages is also difficult to predict and depends on the targeted molecule. Thus, further development of PI3K-Akt-mTOR targeting into a clinical strategy requires detailed molecular studies in well-characterized experimental models combined with careful clinical studies, to identify patient subsets that are likely to respond to this treatment.

The Influence of Immunosuppressive Agents on the Risk of De Novo Donor-Specific HLA Antibody Production in Solid Organ Transplant Recipients

Production of de novo donor-specific antibodies (dnDSA) is a major risk factor for acute and chronic antibody-mediated rejection and graft loss after all solid organ transplantation. In this article, we review the data available on the risk of individual immunosuppressive agents and their ability to prevent dnDSA production. Induction therapy with rabbit antithymocyte globulin may achieve a short-term decrease in dnDSA production in moderately sensitized patients. Rituximab induction may be beneficial in sensitized patients, and in abrogating rebound antibody response in patients undergoing desensitization or treatment for antibody-mediated rejection. Use of bortezomib for induction therapy in at-risk patients is of interest, but the benefits are unproven. In maintenance regimens, nonadherent and previously sensitized patients are not suitable for aggressive weaning protocols, particularly early calcineurin inhibitor withdrawal without lymphocyte-depleting induction. Early conversion to mammalian target of rapamycin inhibitor monotherapy has been reported to increase the risk of dnDSA formation, but a combination of mammalian target of rapamycin inhibitor and reduced-exposure calcineurin inhibitor does not appear to alter the risk. Early steroid therapy withdrawal in standard-risk patients after induction has no known dnDSA penalty. The available data do not demonstrate a consistent effect of mycophenolic acid on dnDSA production. Risk minimization for dnDSA requires monitoring of adherence, appropriate risk stratification, risk-based immunosuppression intensity, and prospective DSA surveillance.

mTOR inhibitors and diabetes

The mammalian target of rapamycin (mTOR) inhibitors are drugs, primarily used as immunosuppressors that are now frequently used as antineoplastic therapies in various cancers (such as advanced renal cell carcinoma, advanced breast cancer, progressive pancreatic neuroendocrine tumors). They act on mTOR signaling pathway which plays a key role in regulating cell growth as well as lipid and glucose metabolism. Treatment with mTOR inhibitors is associated with a high incidence of hyperglycemia and new-onset diabetes, ranging from 13% to 50% in the clinical trials in which they have been used as anticancer therapies. The rate of severe hyperglycemia is also increased, ranging from 4 to 12% in the main phase III clinical trials. Due to limited human studies, the pathophysiology of mTOR inhibitor-induced hyperglycemia has not yet been totally clarified. However, data from animal studies suggest that the mechanisms responsible for hyperglycemia with mTOR inhibitors are likely due to the combination of impaired insulin secretion and insulin resistance. Due to the high rate of hyperglycemia associated with the use of mTOR inhibitors, a close and personalized follow-up of blood glucose is recommended in all patients.

Regulation of innate immune cell function by mTOR

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.

Phosphatase and tensin homolog (PTEN) in antigen-presenting cells controls Th17-mediated autoimmune arthritis

INTRODUCTION

Autoreactive T cells are a central element in many systemic autoimmune diseases. The generation of these pathogenic T cells is instructed by antigen-presenting cells (APCs). However, signaling pathways in APCs that drive autoimmune diseases, such as rheumatoid arthritis, are not understood.

METHODS

We measured phenotypic maturation, cytokine production and induction of T cell proliferation of APCs derived from wt mice and mice with a myeloid-specific deletion of PTEN (myeloid PTEN(-/-)) in vitro and in vivo. We induced collagen-induced arthritis (CIA) and K/BxN serum transfer arthritis in wt and myeloid-specific PTEN(-/-) mice. We measured the cellular composition of lymph nodes by flow cytometry and cytokines in serum and after ex vivo stimulation of T cells.

RESULTS

We show that myeloid-specific PTEN(-/-) mice are almost protected from CIA. Myeloid-specific deletion of PTEN leads to a significant reduction of cytokine expression pivotal for the induction of systemic autoimmunity such as interleukin (IL)-23 and IL-6, leading to a significant reduction of a Th17 type of immune response characterized by reduced production of IL-17 and IL-22. In contrast, myeloid-specific PTEN deficiency did not affect K/BxN serum transfer arthritis, which is independent of the adaptive immune system and solely depends on innate effector functions.

CONCLUSIONS

These data demonstrate that the presence of PTEN in myeloid cells is required for the development of CIA. Deletion of PTEN in myeloid cells inhibits the development of autoimmune arthritis by preventing the generation of a pathogenic Th17 type of immune response.

Integrating canonical and metabolic signalling programmes in the regulation of T cell responses

Over the past decade, our understanding of T cell activation, differentiation and function has markedly expanded, providing a greater appreciation of the signals and pathways that regulate these processes. It has become clear that evolutionarily conserved pathways that regulate stress responses, metabolism, autophagy and survival have crucial and specific roles in regulating T cell responses. Recent studies suggest that the metabolic pathways involving MYC, hypoxia-inducible factor 1α (HIF1α), AMP-activated protein kinase (AMPK) and mammalian target of rapamycin (mTOR) are activated upon antigen recognition and that they are required for directing the consequences of T cell receptor engagement. The purpose of this Review is to provide an integrated view of the role of these metabolic pathways and of canonical T cell signalling pathways in regulating the outcome of T cell responses.

Drugs that modulate aging: the promising yet difficult path ahead

Once a backwater in medical sciences, aging research has emerged and now threatens to take the forefront. This dramatic change of stature is driven from 3 major events. First and foremost, the world is rapidly getting old. Never before have we lived in a demographic environment like today, and the trends will continue such that 20% percent of the global population of 9 billion will be over the age of 60 by 2050. Given current trends of sharply increasing chronic disease incidence, economic disaster from the impending silver tsunami may be ahead. A second major driver on the rise is the dramatic progress that aging research has made using invertebrate models such as worms, flies, and yeast. Genetic approaches using these organisms have led to hundreds of aging genes and, perhaps surprisingly, strong evidence of evolutionary conservation among longevity pathways between disparate species, including mammals. Current studies suggest that this conservation may extend to humans. Finally, small molecules such as rapamycin and resveratrol have been identified that slow aging in model organisms, although only rapamycin to date impacts longevity in mice. The potential now exists to delay human aging, whether it is through known classes of small molecules or a plethora of emerging ones. But how can a drug that slows aging become approved and make it to market when aging is not defined as a disease. Here, we discuss the strategies to translate discoveries from aging research into drugs. Will aging research lead to novel therapies toward chronic disease, prevention of disease or be targeted directly at extending lifespan?

Endocrine side effects of anti-cancer drugs: effects of anti-cancer targeted therapies on lipid and glucose metabolism

During the past years, targeted therapies for cancer have been developed using drugs that have significant metabolic consequences. Among them, the mammalian target of rapamycin (mTOR) inhibitors and, to a much lesser extent, the tyrosine kinase inhibitors (TKIs) are involved. mTOR plays a key role in the regulation of cell growth as well as lipid and glucose metabolism. Treatment with mTOR inhibitors is associated with a significant increase in plasma triglycerides and LDL cholesterol. mTOR inhibitors seem to increase plasma triglycerides by reducing the activity of the lipoprotein lipase which is in charge of the catabolism of triglyceride-rich lipoproteins. The increase in LDL cholesterol observed with mTOR inhibitors seems to be due to a decrease in LDL catabolism secondary to a reduction of LDL receptor expression. In addition, treatment with mTOR inhibitors is associated with a high incidence of hyperglycemia, ranging from 13 to 50% in the clinical trials. The mechanisms responsible for hyperglycemia with new onset diabetes are not clear, but are likely due to the combination of impaired insulin secretion and insulin resistance. TKIs do not induce hyperlipidemia but alter glucose homeostasis. Treatment with TKIs may be associated either with hyperglycemia or hypoglycemia. The molecular mechanism by which TKIs control glucose homeostasis remains unknown. Owing to the metabolic consequences of these agents used as targeted anti-cancer therapies, a specific and personalized follow-up of blood glucose and lipids is recommended when using mTOR inhibitors and of blood glucose when using TKIs.