BACKGROUND: The mechanistic target of rapamycin (mTOR) is a crucial regulator of cell metabolic activity. It forms part of several distinct protein complexes, particularly mTORC1 and mTORC2. The lack of specific inhibitors still hampers the attribution of mTOR functions to these complexes. JR-AB2-011 has been reported as a specific mTORC2 inhibitor preventing mTOR binding to RICTOR, a unique component of mTORC2. We aimed to describe the effects of JR-AB2-011 in leukemia/lymphoma cells, where the mTOR pathway is often aberrantly activated. METHODS: The impact of JR-AB2-011 on leukemia/lymphoma cell metabolism was analyzed using the Seahorse platform. AKT phosphorylation at Ser473 was used as a marker of mTORC2 activity. mTOR binding to RICTOR was assessed by co-immunoprecipitation. RICTOR-null cells were derived from the Karpas-299 cell line using CRISPR/Cas9 gene editing. RESULTS: In leukemia/lymphoma cell lines, JR-AB2-011 induced a rapid drop in the cell respiration rate, which was variably compensated by an increased glycolytic rate. In contrast, an increase in the respiration rate due to JR-AB2-011 treatment was observed in primary leukemia cells. Unexpectedly, JR-AB2-011 did not affect AKT Ser473 phosphorylation. In addition, mTOR did not dissociate from RICTOR in cells treated with JR-AB2-011 under the experimental conditions used in this study. The effect of JR-AB2-011 on cell respiration was retained in RICTOR-null cells. CONCLUSION: JR-AB2-011 affects leukemia/lymphoma cell metabolism via a mechanism independent of mTORC2.

• MeSH
• fosforylace účinky léků   MeSH
• leukemie * farmakoterapie   metabolismus   MeSH
• lidé MeSH
• mTOR inhibitory farmakologie   MeSH
• mTORC2 * metabolismus   MeSH
• nádorové buněčné linie MeSH
• protein RICTOR * metabolismus   MeSH
• protoonkogenní proteiny c-akt metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Studies have suggested a role for the mammalian (or mechanistic) target of rapamycin (mTOR) in skeletal development and homeostasis, yet there is no evidence connecting mTOR with the key signaling pathways that regulate skeletogenesis. We identified a parathyroid hormone (PTH)/PTH-related peptide (PTHrP)-salt-inducible kinase 3 (SIK3)-mTOR signaling cascade essential for skeletogenesis. While investigating a new skeletal dysplasia caused by a homozygous mutation in the catalytic domain of SIK3, we observed decreased activity of mTOR complex 1 (mTORC1) and mTORC2 due to accumulation of DEPTOR, a negative regulator of both mTOR complexes. This SIK3 syndrome shared skeletal features with Jansen metaphyseal chondrodysplasia (JMC), a disorder caused by constitutive activation of the PTH/PTHrP receptor. JMC-derived chondrocytes showed reduced SIK3 activity, elevated DEPTOR, and decreased mTORC1 and mTORC2 activity, indicating a common mechanism of disease. The data demonstrate that SIK3 is an essential positive regulator of mTOR signaling that functions by triggering DEPTOR degradation in response to PTH/PTHrP signaling during skeletogenesis.

• MeSH
• HEK293 buňky MeSH
• homozygot MeSH
• intracelulární signální peptidy a proteiny metabolismus   MeSH
• lidé MeSH
• missense mutace genetika   MeSH
• mTORC1 metabolismus   MeSH
• mTORC2 metabolismus   MeSH
• mutantní proteiny chemie   metabolismus   MeSH
• osteogeneze * MeSH
• parathormon metabolismus   MeSH
• protein podobný parathormonu metabolismus   MeSH
• proteinkinasy chemie   nedostatek   genetika   metabolismus   MeSH
• proteolýza MeSH
• růstová ploténka metabolismus   MeSH
• sekvence aminokyselin MeSH
• signální transdukce * MeSH
• TOR serin-threoninkinasy metabolismus   MeSH
• typy dědičnosti genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

• MeSH
• bevacizumab farmakokinetika   farmakologie   terapeutické užití   MeSH
• biologická terapie MeSH
• bronchogenní karcinom terapie   MeSH
• cetuximab farmakokinetika   farmakologie   terapeutické užití   MeSH
• cílená molekulární terapie * metody   MeSH
• erlotinib farmakokinetika   farmakologie   terapeutické užití   MeSH
• everolimus farmakokinetika   farmakologie   terapeutické užití   MeSH
• gefitinib farmakokinetika   farmakologie   terapeutické užití   MeSH
• geny erbB-1 genetika   účinky léků   MeSH
• humanizované monoklonální protilátky terapeutické užití   MeSH
• inhibitory proteasomu terapeutické užití   MeSH
• inhibitory proteinkinas terapeutické užití   MeSH
• krizotinib farmakokinetika   farmakologie   terapeutické užití   MeSH
• lidé MeSH
• mTORC2 účinky léků   MeSH
• sorafenib farmakokinetika   farmakologie   terapeutické užití   MeSH
• sunitinib farmakokinetika   farmakologie   terapeutické užití   MeSH
• vaskulární endoteliální růstové faktory antagonisté a inhibitory   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• přehledy MeSH

Traumatic spinal cord injury (SCI) is untreatable and remains the leading cause of disability. Neuroprotection and recovery after SCI can be partially achieved by rapamycin (RAPA) treatment, an inhibitor of mTORC1, complex 1 of the mammalian target of rapamycin (mTOR) pathway. However, mechanisms regulated by the mTOR pathway are not only controlled by mTORC1, but also by a second mTOR complex (mTORC2). Second-generation inhibitor, pp242, inhibits both mTORC1 and mtORC2, which led us to explore its therapeutic potential after SCI and compare it to RAPA treatment. In a rat balloon-compression model of SCI, the effect of daily RAPA (5 mg/kg; IP) and pp242 (5 mg/kg; IP) treatment on inflammatory responses and autophagy was observed. We demonstrated inhibition of the mTOR pathway after SCI through analysis of p-S6, p-Akt, and p-4E-BP1 levels. Several proinflammatory cytokines were elevated in pp242-treated rats, while RAPA treatment led to a decrease in proinflammatory cytokines. Both RAPA and pp242 treatments caused an upregulation of LC3B and led to improved functional and structural recovery in acute SCI compared to the controls, however, a greater axonal sprouting was seen following RAPA treatment. These results suggest that dual mTOR inhibition by pp242 after SCI induces distinct mechanisms and leads to recovery somewhat inferior to that following RAPA treatment.

• Publikační typ
• časopisecké články MeSH

Currently, non-alcoholic fatty liver disease (NAFLD) progressing into chronic non-alcoholic steatohepatitis (NASH), liver cirrhosis, and eventually hepatocellular cancer has emerged as an epidemiological concern due to lack of proven treatment. Our review briefly comprises of the mechanism of pathogenesis and inflammation corresponding to the disease, and all the offered insights of mechanistic pathways that could be targeted in the progression of NASH. The review principally focuses on mTOR (mammalian target of rapamycin) as a promising target highlighting its immense role in lipogenesis and alleviating inflammation and fibrosis. A detailed description of signaling pathways of mTORC1 and mTORC2 that are inhibited by rapamycin and other mTOR inhibitor analogues is accentuated. The exploration of mTOR inhibitors clearly explains the exigent molecular aspects of mTOR in regulating adipocyte and lipogenic marker genes (e.g. those encoding PPARγ, SREBP1c). The literature on available mTOR inhibitors and their classification so far could be extremely useful in highlighting mTOR as a favorable drug target in the indication of NASH in the near future.

• MeSH
• hepatocelulární karcinom * patologie   MeSH
• jaterní cirhóza patologie   MeSH
• játra metabolismus   MeSH
• lidé MeSH
• nádory jater * patologie   MeSH
• nealkoholová steatóza jater * metabolismus   MeSH
• TOR serin-threoninkinasy metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Cilia project from almost every cell integrating extracellular cues with signaling pathways. Constitutive activation of FGFR3 signaling produces the skeletal disorders achondroplasia (ACH) and thanatophoric dysplasia (TD), but many of the molecular mechanisms underlying these phenotypes remain unresolved. Here, we report in vivo evidence for significantly shortened primary cilia in ACH and TD cartilage growth plates. Using in vivo and in vitro methodologies, our data demonstrate that transient versus sustained activation of FGF signaling correlated with different cilia consequences. Transient FGF pathway activation elongated cilia, while sustained activity shortened cilia. FGF signaling extended primary cilia via ERK MAP kinase and mTORC2 signaling, but not through mTORC1. Employing a GFP-tagged IFT20 construct to measure intraflagellar (IFT) speed in cilia, we showed that FGF signaling affected IFT velocities, as well as modulating cilia-based Hedgehog signaling. Our data integrate primary cilia into canonical FGF signal transduction and uncover a FGF-cilia pathway that needs consideration when elucidating the mechanisms of physiological and pathological FGFR function, or in the development of FGFR therapeutics.

• MeSH
• achondroplazie genetika   patofyziologie   MeSH
• buňky NIH 3T3 MeSH
• chondrocyty metabolismus   MeSH
• chrupavka metabolismus   MeSH
• cilie patologie   fyziologie   MeSH
• ciliopatie genetika   patofyziologie   MeSH
• fenotyp MeSH
• fibroblastové růstové faktory metabolismus   MeSH
• lidé MeSH
• myši MeSH
• primární buněčná kultura MeSH
• receptor fibroblastových růstových faktorů, typ 3 genetika   metabolismus   MeSH
• růstová ploténka metabolismus   MeSH
• signální transdukce fyziologie   MeSH
• thanatoforní dysplazie genetika   patofyziologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Mechanistic target of rapamycin (mTOR) is a highly conserved protein kinase acting as a central regulator of cell functions. The kinase forms two distinct mTOR complexes termed as mTORC1 and mTORC2. Dysregulation of mTOR activity is associated with various pathological conditions. Inhibition of overactivated mTOR represent a rational approach in the treatment of numerous human diseases. Rapamycin is a potent natural inhibitor of mTOR exhibiting significant antitumor and immunosuppressive activity. Derivatization of rapamycin provided rapalogs, the first generation of mTOR inhibitors that selectively inhibit mTORC1 activity. Further interest of research community resulted in creation of the second generation of mTOR inhibitors involving both, mTOR kinase inhibitors and dual phosphoinositide 3-kinase (PI3K)/mTOR inhibitors. Recently, combining advances of first and second generation of mTOR inhibitors yielded in the third generation of inhibitors termed as rapalinks. Nowadays, novel inhibitors belonging to all of the three generations are still under development. These inhibitors help us better to understand role of mTOR in mTOR signaling pathway as well as in diverse human diseases. In this review, we summarize recent reported mTOR inhibitors or methods of use thereof in the treatment of various diseases.

• MeSH
• fosfatidylinositol-3-kinasy * metabolismus   MeSH
• inhibitory fosfoinositid-3-kinasy farmakologie   MeSH
• inhibitory proteinkinas farmakologie   MeSH
• lidé MeSH
• mTOR inhibitory * MeSH
• mTORC1 metabolismus   MeSH
• proliferace buněk MeSH
• sirolimus farmakologie   MeSH
• TOR serin-threoninkinasy MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

The mammalian target of rapamycin (mTOR) is a Ser/Thr protein kinase conserved in all eukaryotes that plays a key role in cell growth and is a central effector of several pathways regulating essential cell functions. Hyperactivation of the mTORdependent signalling pathway occurs in many human diseases and may be a selective target for their therapy. However, the dual nature of mTOR, existing in two multiprotein complexes mTORC1 and mTORC2 driven by different feedback loops, decreases the therapeutic effects of rapamycin, the specific mTOR inhibitor. In the present study we demonstrate that the mTORC1 signalling pathway is highly activated in human melanoma cells and that up-regulation of this pathway along with the growth and malignity of these cells could be suppressed by disruption of the Src activity. SU6656, the selective inhibitor of the Src kinase activity, decreased up-regulation of the mTORC1 signalling and moreover, unlike rapamycin, it did not induce the activation of Akt/PKB and its downstream targets in HBL melanoma cells. The Src protein was found to be associated with raptor in the mTORC1 complex immunoprecipitated from these cells, suggesting that the Src activity might be a new attractive target for monotherapeutic inhibition of the up-regulated mTORC1 signalling pathway.

• MeSH
• adaptorové proteiny signální transdukční metabolismus   MeSH
• aktivace enzymů účinky léků   MeSH
• fosforylace účinky léků   MeSH
• indoly farmakologie   MeSH
• inhibitory proteinkinas farmakologie   MeSH
• lidé MeSH
• melanom enzymologie   patologie   MeSH
• multiproteinové komplexy antagonisté a inhibitory   metabolismus   MeSH
• nádorové buněčné linie MeSH
• nádorové proteiny metabolismus   MeSH
• proliferace buněk účinky léků   MeSH
• protoonkogenní proteiny c-akt metabolismus   MeSH
• signální transdukce účinky léků   MeSH
• sirolimus farmakologie   MeSH
• skupina kinas odvozených od src-genu antagonisté a inhibitory   metabolismus   MeSH
• sulfonamidy farmakologie   MeSH
• testy nádorových kmenových buněk MeSH
• TOR serin-threoninkinasy antagonisté a inhibitory   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Bruton tyrosine kinase (BTK) inhibitor therapy induces peripheral blood lymphocytosis in chronic lymphocytic leukemia (CLL), which lasts for several months. It remains unclear whether nongenetic adaptation mechanisms exist, allowing CLL cells' survival during BTK inhibitor-induced lymphocytosis and/or playing a role in therapy resistance. We show that in approximately 70% of CLL cases, ibrutinib treatment in vivo increases Akt activity above pretherapy levels within several weeks, leading to compensatory CLL cell survival and a more prominent lymphocytosis on therapy. Ibrutinib-induced Akt phosphorylation (pAktS473) is caused by the upregulation of Forkhead box protein O1 (FoxO1) transcription factor, which induces expression of Rictor, an assembly protein for the mTORC2 protein complex that directly phosphorylates Akt at serine 473 (S473). Knockout or inhibition of FoxO1 or Rictor led to a dramatic decrease in Akt phosphorylation and growth disadvantage for malignant B cells in the presence of ibrutinib (or PI3K inhibitor idelalisib) in vitro and in vivo. The FoxO1/Rictor/pAktS473 axis represents an early nongenetic adaptation to B cell receptor (BCR) inhibitor therapy not requiring PI3Kδ or BTK kinase activity. We further demonstrate that FoxO1 can be targeted therapeutically and its inhibition induces CLL cells' apoptosis alone or in combination with BTK inhibitors (ibrutinib, acalabrutinib, pirtobrutinib) and blocks their proliferation triggered by T cell factors (CD40L, IL-4, and IL-21).

• MeSH
• adenin * analogy a deriváty   farmakologie   MeSH
• chronická lymfatická leukemie * farmakoterapie   metabolismus   genetika   patologie   MeSH
• forkhead box protein O1 * metabolismus   genetika   MeSH
• fosforylace MeSH
• lidé MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• nádorové proteiny metabolismus   genetika   MeSH
• piperidiny * farmakologie   MeSH
• protein RICTOR * genetika   metabolismus   MeSH
• proteinkinasa BTK metabolismus   genetika   antagonisté a inhibitory   MeSH
• protoonkogenní proteiny c-akt * metabolismus   genetika   MeSH
• pyrazoly * farmakologie   MeSH
• pyrimidiny * farmakologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Spinal cord injury (SCI) is a devastating condition that has physical and psychological consequences for patients. SCI is accompanied by scar formation and systemic inflammatory response leading to an intense degree of functional loss. The catechin, epigallocatechin gallate (EGCG), an active compound found in green tea, holds neuroprotective features and is known for its anti-inflammatory potential. The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that exists in two functionally distinct complexes termed mTOR complex 1 and 2 (mTORC1; mTORC2). Inhibition of mTORC1 by rapamycin causes neuroprotection, leading to partial recovery from SCI. In this study the effects of EGCG, PP242 (an inhibitor of both complexes of mTOR), and a combination of EGCG and PP242 in SCI have been examined. It has been found that both EGCG and PP242 significantly improved sensory/motor functions following SCI. However, EGCG appeared to be more effective (BBB motor test, from 2 to 8 weeks after SCI, p = 0.019, p = 0.007, p = 0.006, p = 0.006, p = 0.05, p = 0.006, and p = 0.003, respectively). The only exception was the Von Frey test, where EGCG was ineffective, while mTOR inhibition by PP242, as well as PP242 in combination with EGCG, significantly reduced withdrawal latency starting from week three (combinatorial therapy (EGCG + PP242) vs. control at 3, 5, and 7 weeks, p = 0.011, p = 0.007, and p = 0.05, respectively). It has been found that EGCG was as effective as PP242 in suppressing mTOR signaling pathways, as evidenced by a reduction in phosphorylated S6 expression (PP242 (t-test, p < 0.0001) or EGCG (t-test, p = 0.0002)). These results demonstrate that EGCG and PP242 effectively suppress mTOR pathways, resulting in recovery from SCI in rats, and that EGCG acts via suppressing mTOR pathways.

• Publikační typ
• časopisecké články MeSH