RESUMEN
Regulated Na+ transport in the distal nephron is of fundamental importance to fluid and electrolyte homeostasis. Further upstream, Na+ is the principal driver of secondary active transport of numerous organic and inorganic solutes. In the distal nephron, Na+ continues to play a central role in controlling the body levels and concentrations of a more select group of ions, including K+, Ca++, Mg++, Cl-, and HCO3-, as well as water. Also, of paramount importance are transport mechanisms aimed at controlling the total level of Na+ itself in the body, as well as its concentrations in intracellular and extracellular compartments. Over the last several decades, the transporters involved in moving Na+ in the distal nephron, and directly or indirectly coupling its movement to that of other ions have been identified, and their interrelationships brought into focus. Just as importantly, the signaling systems and their components-kinases, ubiquitin ligases, phosphatases, transcription factors, and others-have also been identified and many of their actions elucidated. This review will touch on selected aspects of ion transport regulation, and its impact on fluid and electrolyte homeostasis. A particular focus will be on emerging evidence for site-specific regulation of the epithelial sodium channel (ENaC) and its role in both Na+ and K+ homeostasis. In this context, the critical regulatory roles of aldosterone, the mineralocorticoid receptor (MR), and the kinases SGK1 and mTORC2 will be highlighted. This includes a discussion of the newly established concept that local K+ concentrations are involved in the reciprocal regulation of Na+-Cl- cotransporter (NCC) and ENaC activity to adjust renal K+ secretion to dietary intake.
Asunto(s)
Canales Epiteliales de Sodio , Túbulos Renales Distales , Aldosterona/metabolismo , Electrólitos/metabolismo , Canales Epiteliales de Sodio/metabolismo , Homeostasis , Transporte Iónico , Túbulos Renales Distales/metabolismo , Sodio/metabolismo , Miembro 3 de la Familia de Transportadores de Soluto 12/metabolismoRESUMEN
Cellular senescence is caused by a wide range of intracellular and extracellular stimuli and influences physiological functions, leading to the progression of age-related diseases. Many studies have shown that cellular senescence is related to phosphatase and tension homolog deleted on chromosome ten (PTEN) loss and mammalian target of rapamycin (mTOR) activation. Although it has been reported that mTOR complex 1 (mTORC1) is major anti-aging target in several cell types, the functions and mechanisms of mTOR complex 2 (mTORC2) during aging have not been elucidated in vascular smooth muscle cells (VSMCs). Therefore, the aim of this study was to reveal the relationship between PTEN and mTORC2 during VSMC senescence. We found adriamycin-induced VSMC senescence was accompanied by reduced PTEN protein expression and upregulation of the mTORC2-Akt (Ser 473) pathway and that fisetin treatment reduced VSMC senescence by increasing PTEN and decreasing mTORC2 protein levels. Furthermore, PTEN played a primary role in the anti-aging effect of fisetin, and fisetin-activated PTEN directly regulated the mTORC2-Akt (Ser 473) signaling pathway, and attenuated senescence phenotypes such as senescence-associated ß-galactosidase (SA-ß-gal) and the p53-p21 signaling pathway in VSMCs. In mouse aortas, fisetin delayed aging by regulating the PTEN-mTORC2-Akt (Ser473) signaling pathway. These results suggest PTEN and mTORC2 are associated with cellular senescence in VSMCs and that the mTORC2-Akt (Ser 473) signaling pathway be considered a new target for preventing senescence-related diseases.
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Flavonoles/farmacología , Músculo Liso Vascular , Fosfohidrolasa PTEN , Animales , Senescencia Celular , Diana Mecanicista del Complejo 2 de la Rapamicina/metabolismo , Ratones , Fosfohidrolasa PTEN/metabolismo , Fosforilación , Proteínas Proto-Oncogénicas c-akt/metabolismoRESUMEN
Natural killer (NK) cells are suitable targets for cancer immunotherapy owing to their potent cytotoxic activity. To maximize the therapeutic efficacy of cancer immunotherapy, adjuvants need to be identified. Resveratrol is a well-studied polyphenol with various potential health benefits, including antitumor effects. We previously found that resveratrol is an NK cell booster, suggesting that it can serve as an adjuvant for cancer immunotherapy. However, the molecular mechanism underlying the activation of NK cells by resveratrol remains unclear. The present study aimed to determine this mechanism. To this end, we investigated relevant pathways in NK cells using Western blot, real-time polymerase chain reaction, pathway inhibitor, protein/DNA array, and cytotoxicity analyses. We confirmed the synergistic effects of resveratrol and interleukin (IL)-2 on enhancing the cytolytic activity of NK cells. Resveratrol activated Akt by regulating Mammalian Target of Rapamycin (mTOR) Complex 2 (mTORC2) via phosphatase and tensin homolog (PTEN) and ribosomal protein S6 kinase beta-1 (S6K1). Moreover, resveratrol-mediated NK cell activation was more dependent on the mTOR pathway than the Akt pathway. Importantly, resveratrol increased the expression of c-Myb, a downstream transcription factor of Akt and mTORC2. Moreover, c-Myb was essential for resveratrol-induced NK cell activation in combination with IL-2. Our results demonstrate that resveratrol activates NK cells through Akt- and mTORC2-mediated c-Myb upregulation.
Asunto(s)
Células Asesinas Naturales/efectos de los fármacos , Activación de Linfocitos , Proteínas Proto-Oncogénicas c-myb/metabolismo , Resveratrol/farmacología , Línea Celular , Humanos , Células Asesinas Naturales/inmunología , Diana Mecanicista del Complejo 2 de la Rapamicina/metabolismo , Fosfohidrolasa PTEN/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Proteínas Proto-Oncogénicas c-myb/genética , Proteínas Quinasas S6 Ribosómicas 70-kDa/metabolismo , Regulación hacia ArribaRESUMEN
CD133 expression in pancreatic cancer correlates with poor prognosis and increased metastasis. CD133+ pancreatic cancer cells exhibit cancer stem cell (CSC)-like properties. We established a CD133+ cell-rich subline from Capan-1 pancreatic cancer cells as a pancreatic CSC model and compared the effects of KU-0063794, a dual mTORC1/mTORC2 inhibitor, against those of mTORC1-specific rapamycin. We found that KU-0063794 prevents sphere formation, a self-renewal index, at high concentrations. Rapamycin inhibited sphere formation but to a lesser degree. In the present study, we aimed to determine the mechanistic roles of mTOR complex 2 (mTORC2) in maintaining CSC-like properties. By examining the PI3K/Akt/mTOR signaling pathway, we observed lower Akt phosphorylation in KU-0063794-treated cells. Phosphorylation of mTORC1 downstream effectors was inhibited by both inhibitors. Thus, mTORC2 activates Akt and modulate stem-like properties, whereas mTORC1 downstream signaling correlates directly with stem-like properties.
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Morfolinas/farmacología , Células Madre Neoplásicas/patología , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patología , Proteínas Proto-Oncogénicas c-akt/metabolismo , Pirimidinas/farmacología , Serina-Treonina Quinasas TOR/genética , Serina-Treonina Quinasas TOR/metabolismo , Antígeno AC133/genética , Antígeno AC133/metabolismo , Expresión Génica , Humanos , Diana Mecanicista del Complejo 1 de la Rapamicina/genética , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Diana Mecanicista del Complejo 2 de la Rapamicina/genética , Diana Mecanicista del Complejo 2 de la Rapamicina/metabolismo , Fosforilación/efectos de los fármacos , Fosforilación/genética , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética , Serina-Treonina Quinasas TOR/fisiología , Células Tumorales CultivadasRESUMEN
Dysregulation of mTORC1/mTORC2 pathway is observed in many cancers and mTORC1 inhibitors have been used clinically in many tumor types; however, the mechanism of mTORC2 in tumorigenesis is still obscure. Here, we mainly explored the potential role of mTORC2 in esophageal squamous cell carcinoma (ESCC) and its effects on the sensitivity of cells to mTOR inhibitors. We demonstrated that RICTOR, the key factor of mTORC2, and p-AKT (Ser473) were excessively activated in ESCC and their overexpression is related to lymph node metastasis and the tumor-node-metastasis (TNM) phase of ESCC patients. Furthermore, we found that mTORC1/ mTORC2 inhibitor PP242 exhibited more efficacious anti-proliferative effect on ESCC cells than mTORC1 inhibitor RAD001 due to RAD001-triggered feedback activation of AKT signal. Another, we demonstrated that down-regulating expression of RICTOR in ECa109 and EC9706 cells inhibited proliferation and migration as well as induced cell cycle arrest and apoptosis. Noteworthy, knocking-down stably RICTOR significantly suppresses RAD001-induced feedback activation of AKT/PRAS40 signaling, and enhances inhibition efficacy of PP242 on the phosphorylation of AKT and PRAS40, thus potentiates the antitumor effect of RAD001 and PP242 both in vitro and in vivo. Our findings highlight that selective targeting mTORC2 could be a promising therapeutic strategy for future treatment of ESCC.
RESUMEN
Multiple viral pathogens can pose a significant health risk to individuals. As a recent example, the ß-coronavirus family virion, SARS-CoV-2, has quickly evolved as a pandemic leading to coronavirus disease 2019 (COVID-19) and has been declared by the World Health Organization as a Public Health Emergency of International Concern. To date, no definitive treatment or vaccine application exists for COVID-19. Although new investigations seek to repurpose existing antiviral treatments for COVID-19, innovative treatment strategies not normally considered to have antiviral capabilities may be critical to address this global concern. One such avenue that may prove to be exceedingly fruitful and offer exciting potential as new antiviral therapy involves the mechanistic target of rapamycin (mTOR) and its associated pathways of mTOR Complex 1 (mTORC1), mTOR Complex 2 (mTORC2), and AMP activated protein kinase (AMPK). Recent work has shown that mTOR pathways in conjunction with AMPK may offer valuable targets to control cell injury, oxidative stress, mitochondrial dysfunction, and the onset of hyperinflammation, a significant disability associated with COVID-19. Furthermore, pathways that can activate mTOR may be necessary for anti-hepatitis C activity, reduction of influenza A virus replication, and vital for type-1 interferon responses with influenza vaccination. Yet, important considerations for the development of safe and effective antiviral therapy with mTOR pathways exist. Under some conditions, mTOR can act as a double edge sword and participate in virion replication and virion release from cells. Future work with mTOR as a potential antiviral target is highly warranted and with a greater understanding of this novel pathway, new treatments against several viral pathogens may successfully emerge.
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Antivirales/farmacología , Infecciones por Coronavirus/tratamiento farmacológico , Infecciones por Coronavirus/metabolismo , Neumonía Viral/tratamiento farmacológico , Neumonía Viral/metabolismo , Serina-Treonina Quinasas TOR/antagonistas & inhibidores , Betacoronavirus , COVID-19 , Humanos , Pandemias , SARS-CoV-2 , Tratamiento Farmacológico de COVID-19RESUMEN
The mTOR complex 2 (mTORC2) is recognized as a promising target for breast cancer treatment. As mTORC2-specific inhibitors do not yet exist, studies into the role of mTORC2 in cancer are performed by deleting Rictor or by RNAi-mediated Rictor silencing. The purpose of this study was to explore the effects of Rictor ablation in bone mesenchymal stromal cells (BMSCs) on bone metastasis of breast cancer. First, female mice with the genotype of Prx1-Cre;Rictorf/f (hereafter RiCKO) or Rictorf/f (as control) were injected intratibially with cells of the breast cancer cell line (TM40D) at 4 months of age. Three weeks later, osteolytic bone destruction was detected in metastatic legs by X-ray and micro-CT. We found that Rictor ablation in BMSCs inhibited TM40D-induced osteolytic bone destruction and resulted in greater bone volume maintenance in vivo. Lower CTX-I serum level, a decreased number of TRAP+ osteoclasts and lower Cathepsin-K expression observed at the tumor-bone interface indicated that osteoclastogenesis was inhibited in RiCKO mice. Additionally, co-culture experiments confirmed that Rictor deletion in BMSCs diminished osteoclast differentiation partly via down regulation of RANKL expression. Furthermore, Rictor deficiency was found to reduce the transition of BMSCs to CAFs coupled with decreased secretion of cytokines (IL-6, RANKL, TGFß), which resulted in lower chemotaxis and less proliferation in TM40D cells. These results suggest that Rictor ablation in BMSCs plays dual roles in breast cancer bone metastasis: (1) repression of osteolytic bone destruction; (2) inhibition of tumor growth.
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Neoplasias Óseas/metabolismo , Neoplasias Óseas/prevención & control , Células Madre Mesenquimatosas/metabolismo , Proteína Asociada al mTOR Insensible a la Rapamicina/metabolismo , Animales , Neoplasias Óseas/secundario , Neoplasias de la Mama/complicaciones , Línea Celular Tumoral , Citocinas/metabolismo , Femenino , Diana Mecanicista del Complejo 2 de la Rapamicina/metabolismo , Ratones , Osteoclastos/metabolismo , Osteogénesis/genética , Osteogénesis/fisiología , Proteína Asociada al mTOR Insensible a la Rapamicina/deficienciaRESUMEN
A wide variety of genetic, pharmacological and nutrient manipulations that extend lifespan in model organisms do so in a manner dependent upon increased autophagic flux. However, our recent findings suggest that when mitochondrial membrane integrity is compromised, macroautophagy/autophagy can be detrimental. In C. elegans lacking the serine/threonine kinase mechanistic target of rapamycin kinase complex 2 and its downstream effector SGK-1 (Serum- and Glucocorticoid-inducible Kinase homolog), lifespan is shortened in spite of increased levels of autophagy, whereas reducing autophagy restores normal lifespan. This is due to a concomitant defect in mitochondrial permeability in mutants defective in either SGK-1 or mechanistic target of rapamycin kinase complex 2, attributable to increased VDAC-1 (VDAC Voltage Dependent Anion Channel homolog) protein level. More generally, we find that induction of mitochondrial permeability reverses each and every tested paradigm of autophagy-dependent lifespan extension and, further, exacerbates ischemia-reperfusion injury. In this punctum, we discuss our finding that autophagy with increased mitochondrial permeability is a detrimental combination conserved from nematode to mammals.
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Autofagia/fisiología , Animales , Animales Modificados Genéticamente , Autofagia/efectos de los fármacos , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Regulación hacia Abajo/efectos de los fármacos , Regulación hacia Abajo/genética , Humanos , Diana Mecanicista del Complejo 2 de la Rapamicina/antagonistas & inhibidores , Ratones , Ratones Noqueados , Proteínas de Transporte de Membrana Mitocondrial/genética , Proteínas de Transporte de Membrana Mitocondrial/metabolismo , Membranas Mitocondriales/metabolismo , Poro de Transición de la Permeabilidad Mitocondrial , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Proteína Asociada al mTOR Insensible a la Rapamicina/genética , Proteína Asociada al mTOR Insensible a la Rapamicina/metabolismo , Daño por Reperfusión/genética , Daño por Reperfusión/metabolismo , Daño por Reperfusión/patología , Transducción de Señal/efectos de los fármacos , Sirolimus/farmacología , Canal Aniónico 1 Dependiente del Voltaje/genética , Canal Aniónico 1 Dependiente del Voltaje/metabolismoRESUMEN
Mitochondria are major sites of energy metabolism that influence numerous cellular events, including immunity and cancer development. Previously, we reported that the mitochondrion-specific antioxidant enzyme, manganese-containing superoxide dismutase (MnSOD), has dual roles in early- and late-carcinogenesis stages. However, how defective MnSOD impacts the chain of events that lead to cell transformation in pathologically normal epidermal cells that have been exposed to carcinogens is unknown. Here, we show that UVB radiation causes nitration and inactivation of MnSOD leading to mitochondrial injury and mitophagy. In keratinocytes, exposure to UVB radiation decreased mitochondrial oxidative phosphorylation, increased glycolysis and the expression of autophagy-related genes, and enhanced AKT Ser/Thr kinase (AKT) phosphorylation and cell growth. Interestingly, UVB initiated a prosurvival mitophagy response by mitochondria-mediated reactive oxygen species (ROS) signaling via the mammalian target of the mTOR complex 2 (mTORC2) pathway. Knockdown of rictor but not raptor abrogated UVB-induced mitophagy responses. Furthermore, fractionation and proximity-ligation assays reveal that ROS-mediated mTOC2 activation in mitochondria is necessary for UVB-induced mitophagy. Importantly, pretreatment with the MnSOD mimic MnTnBuOE-2-PyP5+ (MnP) attenuates mTORC2 activation and suppresses UVB-induced mitophagy. UVB radiation exposure also increased cell growth as assessed by soft-agar colony survival and cell growth assays, and pretreatment with MnP or the known autophagy inhibitor 3-methyladenine abrogated UVB-induced cell growth. These results indicate that MnSOD is a major redox regulator that maintains mitochondrial health and show that UVB-mediated MnSOD inactivation promotes mitophagy and thereby prevents accumulation of damaged mitochondria.
Asunto(s)
Diana Mecanicista del Complejo 2 de la Rapamicina/metabolismo , Mitofagia/efectos de la radiación , Especies Reactivas de Oxígeno/metabolismo , Superóxido Dismutasa/antagonistas & inhibidores , Rayos Ultravioleta , Animales , Autofagia/fisiología , Línea Celular , Ratones , Mitocondrias/efectos de los fármacos , Mitocondrias/enzimología , Mitocondrias/metabolismo , Nitratos/metabolismo , Oxidación-Reducción , Proteína Asociada al mTOR Insensible a la Rapamicina/fisiología , Proteína Reguladora Asociada a mTOR/fisiologíaRESUMEN
Interactions between the tumor cells and bone marrow (BM) microenvironment promote survival, growth, and chemoresistance of acute myeloid leukemia (AML). The mTOR pathway plays a key role in mediating the AML-BM microenvironment interactions. Here, we report the anti-AML activity of a natural monomer extracted from the Chinese medicinal herb Evodia rutaecarpa, dihydroevocarpine. Our results showed that dihydroevocarpine-induced cytotoxicity, apoptosis, and G0/G1 arrest in AML cells, and inhibited the tumor growth in an AML xenograft model. Importantly, our study revealed that the dihydroevocarpine treatment inhibited the mTOR pathway via suppressing the mTORC1/2 activity, and thus overcame the protective effect of the BM microenvironment on AML cells. Taken together, our findings suggest that dihydroevocarpine could be used as a potential anti-AML agent alone or a therapeutic adjunct in AML therapy, particularly in the presence of the BM microenvironment.
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Antineoplásicos/farmacología , Leucemia Mieloide Aguda , Diana Mecanicista del Complejo 1 de la Rapamicina/efectos de los fármacos , Diana Mecanicista del Complejo 2 de la Rapamicina/metabolismo , Extractos Vegetales/farmacología , Animales , Apoptosis/efectos de los fármacos , Médula Ósea/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Evodia/química , Células HL-60 , Humanos , Leucemia Mieloide Aguda/metabolismo , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Ratones , Ratones Desnudos , Transducción de Señal/efectos de los fármacos , Microambiente Tumoral/efectos de los fármacos , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that controls a wide spectrum of cellular processes, including cell growth, differentiation, and metabolism. mTOR forms two distinct multiprotein complexes known as mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2), which are characterized by the presence of raptor and rictor, respectively. mTOR controls insulin signaling by regulating several downstream components such as growth factor receptor-bound protein 10 (Grb10), insulin receptor substrate (IRS-1), F-box/WD repeat-containing protein 8 (Fbw8), and insulin like growth factor 1 receptor/insulin receptor (IGF-IR/IR). In addition, mTORC1 and mTORC2 regulate each other through a feedback loop to control cell growth. This review outlines the current understanding of mTOR regulation in insulin signaling in the context of whole body metabolism.
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Insulina/metabolismo , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Diana Mecanicista del Complejo 2 de la Rapamicina/metabolismo , Serina-Treonina Quinasas TOR/metabolismo , Animales , Proliferación Celular , Proteínas F-Box/metabolismo , Proteína Adaptadora GRB10/metabolismo , Humanos , Proteínas Sustrato del Receptor de Insulina/metabolismo , Proteína Asociada al mTOR Insensible a la Rapamicina/metabolismo , Receptor IGF Tipo 1/metabolismo , Receptor de Insulina/metabolismo , Proteína Reguladora Asociada a mTOR/metabolismo , Transducción de SeñalRESUMEN
BACKGROUND: The mammalian circadian clock and its associated clock genes are increasingly been recognized as critical components for a number of physiological and disease processes that extend beyond hormone release, thermal regulation, and sleep-wake cycles. New evidence suggests that clinical behavior disruptions that involve prolonged shift work and even space travel may negatively impact circadian rhythm and lead to multi-system disease. METHODS: In light of the significant role circadian rhythm can hold over the body's normal physiology as well as disease processes, we examined and discussed the impact circadian rhythm and clock genes hold over lifespan, neurodegenerative disorders, and tumorigenesis. RESULTS: In experimental models, lifespan is significantly reduced with the introduction of arrhythmic mutants and leads to an increase in oxidative stress exposure. Interestingly, patients with Alzheimer's disease and Parkinson's disease may suffer disease onset or progression as a result of alterations in the DNA methylation of clock genes as well as prolonged pharmacological treatment for these disorders that may lead to impairment of circadian rhythm function. Tumorigenesis also can occur with the loss of a maintained circadian rhythm and lead to an increased risk for nasopharyngeal carcinoma, breast cancer, and metastatic colorectal cancer. Interestingly, the circadian clock system relies upon the regulation of the critical pathways of autophagy, the mechanistic target of rapamycin (mTOR), AMP activated protein kinase (AMPK), and silent mating type information regulation 2 homolog 1 (Saccharomyces cerevisiae) (SIRT1) as well as proliferative mechanisms that involve the wingless pathway of Wnt/ß-catenin pathway to foster cell survival during injury and block tumor cell growth. CONCLUSION: Future targeting of the pathways of autophagy, mTOR, SIRT1, and Wnt that control mammalian circadian rhythm may hold the key for the development of novel and effective therapies against aging- related disorders, neurodegenerative disease, and tumorigenesis.
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Autofagia/genética , Ritmo Circadiano/fisiología , Neoplasias , Enfermedades Neurodegenerativas , Sirtuina 1 , Serina-Treonina Quinasas TOR , Animales , Humanos , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/fisiopatología , Enfermedades Neurodegenerativas/genética , Enfermedades Neurodegenerativas/metabolismo , Enfermedades Neurodegenerativas/fisiopatología , Sirtuina 1/genética , Sirtuina 1/metabolismo , Serina-Treonina Quinasas TOR/genética , Serina-Treonina Quinasas TOR/metabolismoRESUMEN
Although signaling from phosphatidylinositol 3-kinase (PI3K) and AKT to mechanistic target of rapamycin (mTOR) is prominently dysregulated in high-grade glial brain tumors, blockade of PI3K or AKT minimally affects downstream mTOR activity in glioma. Allosteric mTOR inhibitors, such as rapamycin, incompletely block mTORC1 compared with mTOR kinase inhibitors (TORKi). Here, we compared RapaLink-1, a TORKi linked to rapamycin, with earlier-generation mTOR inhibitors. Compared with rapamycin and Rapalink-1, TORKi showed poor durability. RapaLink-1 associated with FKBP12, an abundant mTOR-interacting protein, enabling accumulation of RapaLink-1. RapaLink-1 showed better efficacy than rapamycin or TORKi, potently blocking cancer-derived, activating mutants of mTOR. Our study re-establishes mTOR as a central target in glioma and traces the failure of existing drugs to incomplete/nondurable inhibition of mTORC1.
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Neoplasias Encefálicas/tratamiento farmacológico , Glioblastoma/tratamiento farmacológico , Complejos Multiproteicos/antagonistas & inhibidores , Inhibidores de Proteínas Quinasas/uso terapéutico , Serina-Treonina Quinasas TOR/antagonistas & inhibidores , Animales , Línea Celular Tumoral , Femenino , Humanos , Diana Mecanicista del Complejo 1 de la Rapamicina , Ratones , Ratones Endogámicos BALB C , Sirolimus/uso terapéutico , Proteína 1A de Unión a Tacrolimus/fisiologíaRESUMEN
BACKGROUND: Transient receptor potential (TRP) channels are a superfamily of ion channels termed after the trp gene in Drosophila that are diverse in structure and control a wide range of biological functions including cell development and growth, thermal regulation, and vascular physiology. Of significant interest is the transient receptor potential cation channel subfamily V member 1 (TRPV1) receptor, also known as the capsaicin receptor and the vanilloid receptor 1, that is a non-selective cation channel sensitive to a host of external stimuli including capsaicin and camphor, venoms, acid/basic pH changes, and temperature. METHODS: Given the multiple modalities that TRPV1 receptors impact in the body, we examined and discussed the role of these receptors in vasomotor control, metabolic disorders, cellular injury, oxidative stress, apoptosis, autophagy, and neurodegenerative disorders and their overlap with other signal transduction pathways that impact trophic factors. RESULTS: Surprisingly, TRPV1 receptors do not rely entirely upon calcium signaling to affect cellular biology, but also have a close relationship with the mechanistic target of rapamycin (mTOR), AMP activated protein kinase (AMPK), and protein kinase B (Akt) that have roles in pain sensitivity, stem cell development, cellular survival, and cellular metabolism. These pathways with TRPV1 converge in the signaling of growth factors with recent work highlighting a relationship with erythropoietin (EPO). Angiogenesis and endothelial tube formation controlled by EPO requires, in part, the activation of TRPV1 receptors in conjunction with Akt and AMPK pathways. CONCLUSION: TRPV1 receptors could prove to become vital to target disorders of vascular origin and neurodegeneration. Broader and currently unrealized implementations for both EPO and TRPV1 receptors can be envisioned for for the development of novel therapeutic strategies in multiple systems of the body.
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Eritropoyetina/metabolismo , Enfermedades Neurodegenerativas/metabolismo , Proteínas Quinasas/metabolismo , Transducción de Señal/fisiología , Serina-Treonina Quinasas TOR/metabolismo , Canales Catiónicos TRPV/metabolismo , Quinasas de la Proteína-Quinasa Activada por el AMP , Animales , Calcio/metabolismo , HumanosRESUMEN
OBJECTIVE Multiple factors may affect functional recovery after peripheral nerve injury, among them the lesion site and the interval between the injury and the surgical repair. When the nerve segment distal to the lesion site undergoes chronic degeneration, the ensuing regeneration (when allowed) is often poor. The aims of the current study were as follows: 1) to examine the expression changes of the neuregulin 1/ErbB system during long-term nerve degeneration; and 2) to investigate whether a chronically denervated distal nerve stump can sustain nerve regeneration of freshly axotomized axons. METHODS This study used a rat surgical model of delayed nerve repair consisting of a cross suture between the chronically degenerated median nerve distal stump and the freshly axotomized ulnar proximal stump. Before the suture, a segment of long-term degenerated median nerve stump was harvested for analysis. Functional, morphological, morphometric, and biomolecular analyses were performed. RESULTS The results showed that neuregulin 1 is highly downregulated after chronic degeneration, as well as some Schwann cell markers, demonstrating that these cells undergo atrophy, which was also confirmed by ultrastructural analysis. After delayed nerve repair, it was observed that chronic degeneration of the distal nerve stump compromises nerve regeneration in terms of functional recovery, as well as the number and size of regenerated myelinated fibers. Moreover, neuregulin 1 is still downregulated after delayed regeneration. CONCLUSIONS The poor outcome after delayed nerve regeneration might be explained by Schwann cell impairment and the consequent ineffective support for nerve regeneration. Understanding the molecular and biological changes occurring both in the chronically degenerating nerve and in the delayed nerve repair may be useful to the development of new strategies to promote nerve regeneration. The results suggest that neuregulin 1 has an important role in Schwann cell activity after denervation, indicating that its manipulation might be a good strategy for improving outcome after delayed nerve repair.
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Regeneración Nerviosa , Traumatismos de los Nervios Periféricos/fisiopatología , Células de Schwann , Animales , Desnervación , Femenino , Degeneración Nerviosa , Neurregulina-1/fisiología , Ratas , Ratas Wistar , Recuperación de la Función , Factores de TiempoRESUMEN
OBJECTIVES: Cumulus cells play a crucial role as essential mediators in the maturation of ova. Ginger contains 10-gingerol, which induces apoptosis in colon cancer cells. Based on this hypothesis, this study aimed to determine whether 10-gingerol is able to induce apoptosis in normal cells, namely, cumulus cells. METHODS: This study used an in vitro analysis by culturing Cumulus cells in M199 containing 10-gingerol in various concentrations (12, 16, and 20 µM) and later detected early apoptotic activity using an Annexin V-FITC detection kit. RESULT: The in vitro data revealed that the number of apoptosis cells increased along with the period of incubation as follows: 12 µM (63.71% ± 2.192%); 16 µM (74.51% ± 4.596%); and 20 µM (78.795% ± 1.435%). The substance 10-gingerol induces apoptosis in cumulus cells by inhibiting HTR1A functions and inactivating GSK3B and AKT-1. CONCLUSIONS: These findings indicate that further examination is warranted for 10-gingerol as a contraception agent.
RESUMEN
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 ß-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.
RESUMEN
The mammalian target of rapamycin complex 2 (mTORC2) contains the essential protein RICTOR and is activated by growth factors. mTORC2 in adipose tissue contributes to the regulation of glucose and lipid metabolism. In the perivascular adipose tissue, mTORC2 ensures normal vascular reactivity by controlling expression of inflammatory molecules. To assess whether RICTOR/mTORC2 contributes to blood pressure regulation, we applied a radiotelemetry approach in control and Rictor knockout (Rictor(aP2KO)) mice generated using adipocyte protein-2 gene promoter-driven CRE recombinase expression to delete Rictor. The 24-hour mean arterial pressure was increased in Rictor(aP2KO) mice, and the physiological decline in mean arterial pressure during the dark period was impaired. In parallel, heart rate and locomotor activity were elevated during the dark period with a pattern similar to blood pressure changes. This phenotype was associated with mild cardiomyocyte hypertrophy, decreased cardiac natriuretic peptides, and their receptor expression in adipocytes. Moreover, clock gene expression was reduced or phase-shifted in perivascular adipose tissue. No differences in clock gene expression were observed in the master clock suprachiasmatic nucleus, although Rictor gene expression was also lower in brain of Rictor(aP2KO) mice. Thus, this study highlights the importance of RICTOR/mTORC2 for interactions between vasculature, adipocytes, and brain to tune physiological outcomes, such as blood pressure and locomotor activity.
Asunto(s)
Tejido Adiposo/metabolismo , Presión Sanguínea/fisiología , Encéfalo/metabolismo , Proteínas CLOCK/metabolismo , Proteínas Portadoras/genética , Proteínas Portadoras/metabolismo , Eliminación de Gen , Animales , Proteínas CLOCK/genética , Expresión Génica , Frecuencia Cardíaca/fisiología , Hipertrofia , Insulina/metabolismo , Diana Mecanicista del Complejo 2 de la Rapamicina , Ratones , Ratones Noqueados , Modelos Animales , Actividad Motora/fisiología , Complejos Multiproteicos/metabolismo , Miocitos Cardíacos/patología , Proteína Asociada al mTOR Insensible a la Rapamicina , Serina-Treonina Quinasas TOR/metabolismo , Vasoconstricción/fisiologíaRESUMEN
It has been reported that persistent or excessive autophagy promotes cancer cell death during chemotherapy, either by enhancing the induction of apoptosis or mediating autophagic cell death. Here, we show that miR-15a and miR-16 are potent inducers of autophagy. Rictor, a component of mTORC2 complex, is directly targeted by miR-15a/16. Overexpression of miR-15a/16 or depletion of endogenous Rictor attenuates the phosphorylation of mTORC1 and p70S6K, inhibits cell proliferation and G1/S cell cycle transition in human cervical carcinoma HeLa cells. Moreover, miR-15a/16 dramatically enhances anticancer drug camptothecin (CPT)-induced autophagy and apoptotic cell death in HeLa cells. Collectively, these data demonstrate that miR-15a/16 induced autophagy contribute partly to their inhibition of cell proliferation and enhanced chemotherapeutic efficacy of CPT.
Asunto(s)
Antineoplásicos Fitogénicos/farmacología , Autofagia/genética , Camptotecina/farmacología , Resistencia a Antineoplásicos/genética , MicroARNs/genética , Regiones no Traducidas 3' , Secuencia de Bases , Sitios de Unión , Proteínas Portadoras/genética , Línea Celular Tumoral , Proliferación Celular , Técnicas de Silenciamiento del Gen , Células HeLa , Humanos , Interferencia de ARN , Proteína Asociada al mTOR Insensible a la RapamicinaRESUMEN
Recent studies have identified that constitutively active phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling is an important feature of osteosarcoma, where it promotes cell proliferation, survival, and chemo-resistance. Here, we studied the therapeutic potential of NVP-BEZ235, a novel dual PI3K/mTOR dual inhibitor, on osteosarcoma cells in vivo and in vitro. NVP-BEZ235 was cytotoxic and cytostatic to a panel of osteosarcoma lines (MG-63, U2OS and SaOs-2), where it induce apoptosis and cell-cycle arrest. At the molecular level, NVP-BEZ235 inhibited PI3K-AKT-mTORC1 activation and downregulated cyclin D1/cyclin B1 expressions, while increasing MEK/Erk phosphorylation in osteosarcoma cells. MEK/Erk inhibitors PD98059 and MEK-162 increased NVP-BEZ235 activity on osteosarcoma cells. In vivo, oral NVP-BEZ235 inhibited U2OS xenograft in SCID mice, and its anti-tumor efficiency was further enhanced by MEK-162 co-administration. Taken together, our findings indicate that dual inhibition of PI3K and mTOR with NVP-BEZ235, either alone or in combination with MEK/Erk inhibitors, may be an efficient treatment for osteosarcoma.