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1.
Angiogenesis ; 20(1): 55-71, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27743086

RESUMO

Hypoxia is a feature of all solid tumours, contributing to tumour progression. Activation of HIF-1α plays a critical role in promoting tumour angiogenesis and metastasis. Since its expression is positively correlated with poor prognosis for cancer patients, HIF-1α is one of the most convincing anticancer targets. BP-1T is a novel antiproliferative agent with promising antiangiogenic effects. In the present study, the molecular mechanism underlying cytotoxic/antiangiogenic effects of BP-1T on tumour/non-tumour angiogenesis was evaluated. Evidences show that BP-1T exhibits potent cytotoxicity with prolonged activity and effectively regressed neovessel formation both in reliable non-tumour and tumour angiogenic models. The expression of CoCl2-induced HIF-1α was inhibited by BP-1T in various p53 (WT)-expressing cancer cells, including A549, MCF-7 and DLA, but not in mutant p53-expressing SCC-9 cells. Mechanistically, BP-1T mediates the HIF-1α proteasomal degradation by activating p53/MDM2 pathway and thereby downregulated HIF-1α-dependent angiogenic genes such as VEGF-A, Flt-1, MMP-2 and MMP-9 under hypoxic condition of in vitro and in vivo solid tumour, eventually leading to abolition of migration and invasion. Based on these observations, we conclude that BP-1T acts on HIF-1α degradation through p53/MDM2 proteasome pathway.


Assuntos
Inibidores da Angiogênese/farmacologia , Benzofenonas/farmacologia , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteólise/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Tiazóis/farmacologia , Proteína Supressora de Tumor p53/metabolismo , Animais , Benzofenonas/química , Carcinogênese/metabolismo , Carcinogênese/patologia , Morte Celular/efeitos dos fármacos , Linhagem Celular , Movimento Celular/efeitos dos fármacos , Modelos Animais de Doenças , Progressão da Doença , Regulação da Expressão Gênica/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Concentração Inibidora 50 , Camundongos , Microvasos/patologia , Modelos Biológicos , Neovascularização Fisiológica/efeitos dos fármacos , Ratos , Transdução de Sinais/efeitos dos fármacos , Tiazóis/química
2.
Cancer Cell ; 10(4): 269-80, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17045205

RESUMO

Akt contributes to tumorigenesis by inhibiting apoptosis. Here we establish that Akt is required for normal cell proliferation and susceptibility to oncogenesis independently of its antiapoptotic activity. Partial ablation of Akt activity by deleting Akt1 inhibits cell proliferation and oncogenesis. These effects are compounded by deleting both Akt1 and Akt2. In vivo, Akt1 null mice are resistant to MMTV-v-H-Ras-induced tumors and to skin carcinogenesis. Thus, partial ablation of Akt activity is sufficient to suppress tumorigenesis in vitro and in vivo. The effect of Akt deficiency on cell proliferation and oncogenesis is p53 independent but mTORC1 dependent. Surprisingly, upon mTORC1 hyperactivation, the reduction in Akt activity does not impair cell proliferation and susceptibility to oncogenic transformation; thus, Akt may mediate these processes exclusively via mTORC1.


Assuntos
Proliferação de Células , Neoplasias/etiologia , Proteínas Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/deficiência , Transativadores/metabolismo , Animais , Linhagem Celular Transformada , Transformação Celular Viral , Cruzamentos Genéticos , Embrião de Mamíferos , Fibroblastos/metabolismo , Cinética , Alvo Mecanístico do Complexo 1 de Rapamicina , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Complexos Multiproteicos , Neoplasias/patologia , Proteínas Quinases/genética , Proteínas , Proteínas Proto-Oncogênicas c-akt/genética , Retroviridae/genética , Serina-Treonina Quinases TOR , Transativadores/genética , Fatores de Transcrição , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo
3.
Arch Pharm (Weinheim) ; 347(4): 247-55, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24343903

RESUMO

Xanthine oxidase (XO) is a complex metalloflavoprotein, the overproduction of which usually leads to a pathological condition called gout. The XO inhibitors may prove to be promising antigout agents. The XO generates superoxide anions and H2O2 for the self-defense system of the organism. Abnormal production of this superoxide (reactive oxygen species) is responsible for a number of complications including inflammation, metabolic disorder, cellular aging, reperfusion damage, atherosclerosis, and carcinogenesis. In this paper, we report the synthesis of N-substituted analogs of thiazolidinedione derivatives as effective and new class of XO inhibitors and also as antioxidant agents. Among all the compounds in the series, compound 2i produced relatively better activity against human milk XO (72% inhibition), which was also supported by docking studies.


Assuntos
Antioxidantes/farmacologia , Tiazolidinedionas/farmacologia , Xantina Oxidase/antagonistas & inibidores , Animais , Antioxidantes/síntese química , Antioxidantes/química , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacologia , Humanos , Leite Humano/enzimologia , Simulação de Acoplamento Molecular , Ratos , Espécies Reativas de Oxigênio/metabolismo , Tiazolidinedionas/síntese química , Tiazolidinedionas/química
4.
Indian J Exp Biol ; 51(5): 352-6, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23821822

RESUMO

Dendritic cells (DC) which are located at the interface of innate and adaptive immunity are targets of infection by many RNA and DNA viruses. Advances in the ex vivo generation of monocyte derived non proliferating dendritic cells have been used for clinical application like immunotherapy. IL-4 cytokine plays essential role in the maturation and generation of DCs. Bos indicus interleukin 4 (boIL-4) 408 bp was amplified from PBMC's and cloned in pBSIIKS+ vector. The sequence analysis showed N terminal 69 bp signal sequence and one N-glycosylation site. The phylogenetic tree analysis showed that Bos indicus IL-4 is closely related to the ruminant IL-4 and least sharing of genetic line of human and mouse IL-4. The recombinant bolL-4 protein was expressed in CHO cells which secreted a 16 kDa protein which was confirmed by SDS PAGE and western blotting. The rec-boIL-4 protein proliferated the bovine PBMC's, decreased production of nitric oxide in antigen stimulated macrophages, and phagocytosed the micro particles confirming its activity on dendritic cells.


Assuntos
Interleucina-4/genética , Animais , Sequência de Bases , Bovinos , Clonagem Molecular , Primers do DNA , Eletroforese em Gel de Poliacrilamida , Reação em Cadeia da Polimerase
5.
Acta Crystallogr Sect E Struct Rep Online ; 69(Pt 11): o1676, 2013 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-24454109

RESUMO

In the mol-ecule of the title compound, C15H14O2, the dihedral angle between the benzene and phenyl rings is 61.27 (8)°. In the crystal, O-H⋯O and weak C-H⋯O hydrogen bonds link the mol-ecules into chains extending along the c-axis direction.

6.
Dev Cell ; 12(4): 487-502, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17419990

RESUMO

The regulatory circuits that control the activities of the two distinct target of rapamycin (TOR) complexes, TORC1 and TORC2, and of Akt have been a focus of intense research in recent years. It has become increasingly evident that these regulatory circuits control some of the most fundamental aspects of metabolism, cell growth, proliferation, survival, and differentiation at both the cellular and organismal levels. As such, they also play a pivotal role in the genesis of diseases including cancer, diabetes, aging, and degenerative diseases. This review highlights recent developments aimed at deciphering the interplay between Akt and mTORCs as well as their role in embryonic development and in cancer.


Assuntos
Regulação da Expressão Gênica , Neoplasias/metabolismo , Fosfoproteínas/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fatores de Transcrição/metabolismo , Animais , Sequência Conservada , Evolução Molecular , Desenvolvimento Fetal , Humanos , Camundongos , Camundongos Knockout , Modelos Biológicos , Fosfoproteínas/genética , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Transdução de Sinais , Transativadores/metabolismo , Fatores de Transcrição/genética
7.
Acta Crystallogr Sect E Struct Rep Online ; 68(Pt 8): o2435, 2012 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-22904883

RESUMO

The asymmetric unit of the title compound, C(19)H(19)ClO(4), contains two independent mol-ecules. The dihedral angles between the benzene rings are 63.41 (8) and 61.41 (9)°. Adjacent mol-ecules of different types are inter-connected in pairs through π-π inter-actions between their central benzene rings [centroid-centroid separation = 3.801 (2) Å, inter-planar spacing = 3.605 (2) Å, centroid shift = 1.204 (2) Å]. Finally, C-H⋯O hydrogen bonds link these dimers into bilayers parallel to (100).

8.
Biomed Pharmacother ; 112: 108707, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30970513

RESUMO

The synthesis and antiproliferative effect of a series of quinoline and thiazole containing coumarin analogs 12a-d and 13a-f respectively, on mice leukemic cells was performed. The chemical structures of newly synthesized compounds were confirmed by IR, 1H NMR, 13C NMR and mass spectral analysis. The result indicates that, 7-methoxy-2-oxo-2H-chromene-3-carboxylic acid [4-(4-methoxy-phenyl)-thiazol-2-yl]-amide (13f) showed potent activity against EAC and DLA cells in MTT (15.3 µM), tryphan blue (15.6 µM) and LDH (14.2 µM) leak assay with 5-fluorouracil as a standard. Further, the anti-neoplastic effect of the compound 13f was verified against Ehrlich ascites tumour by BrdU incorporation, TUNEL, FACS and DNA fragmentation assays. Experimental data showed that compound 13f induces the apoptotic cell death by activating apoptotic factors such as caspase-8 &-3, CAD, Cleaved PARP, γ-H2AX and by degrading genomic DNA of cancer cells and thereby decreasing the ascitic tumour development in mice. Besides, compound 13f was also subjected for docking studies to approve the in vitro and in vivo studies. The data revealed that the compound 13f has very good interaction with caspase 3 protein by binding with amino acid Arg 207 through hydrogen bond.


Assuntos
Antineoplásicos/síntese química , Apoptose/efeitos dos fármacos , Carcinoma de Ehrlich/tratamento farmacológico , Cumarínicos/síntese química , Quinolinas/química , Tiazóis/química , Animais , Antineoplásicos/química , Antineoplásicos/uso terapêutico , Antineoplásicos/toxicidade , Carcinoma de Ehrlich/patologia , Linhagem Celular Tumoral , Simulação por Computador , Cumarínicos/química , Cumarínicos/uso terapêutico , Cumarínicos/toxicidade , Dose Letal Mediana , Camundongos , Relação Estrutura-Atividade
9.
Front Microbiol ; 8: 1315, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28769891

RESUMO

Host cells produce variety of antiviral factors that create an antiviral state and target various stages of influenza A virus (IAV) life cycle to inhibit infection. However, IAV has evolved various strategies to antagonize those antiviral factors. Recently, we reported that a member of class I host histone deacetylases (HDACs), HDAC1 possesses an anti-IAV function. Herein, we provide evidence that HDAC2, another class I member and closely related to HDAC1 in structure and function, also possesses anti-IAV properties. In turn, IAV, like HDAC1, dysregulates HDAC2, mainly at the polypeptide level through proteasomal degradation to potentially minimize its antiviral effect. We found that IAV downregulated the HDAC2 polypeptide level in A549 cells in an H1N1 strain-independent manner by up to 47%, which was recovered to almost 100% level in the presence of proteasome-inhibitor MG132. A further knockdown in HDAC2 expression by up to 90% via RNA interference augmented the growth kinetics of IAV in A549 cells by more than four-fold after 24 h of infection. Furthermore, the knockdown of HDAC2 expression decreased the IAV-induced phosphorylation of the transcription factor, Signal Transducer and Activator of Transcription I (STAT1) and the expression of interferon-stimulated gene, viperin in infected cells by 41 and 53%, respectively. The role of HDAC2 in viperin expression was analogous to that of HDAC1, but it was not in the phosphorylation of STAT1. This indicated that, like HDAC1, HDAC2 is a component of IAV-induced host innate antiviral response and performs both redundant and non-redundant functions vis-a-vis HDAC1; however, IAV dysregulates them both in a redundant manner.

10.
ChemistryOpen ; 4(6): 662, 2015 12.
Artigo em Inglês | MEDLINE | ID: mdl-27308188

RESUMO

Invited for this month's cover picture is the group of Professor Antony Fairbanks and his collaborators at the University of Canterbury and University of Otago. The cover shows the isolation of complex bi-antennary oligosaccharides from hens' eggs and their conjugation to gold nanoparticles. Gold nanoparticles carrying these sugars can then bind to specific receptors (hemagglutinin) on the surface of the influenza virus, causing particle aggregation, which changes their spectroscopic properties. Upon aggregation, they undergo a red-shift in their surface plasmon resonance, as illustrated by the bound particles shining in the cover image. These changes in spectroscopic properties are the basis of a detection system capable of detecting viral hemagglutinin at nanomolar concentrations, as well as the virus itself. For more details, see the Full Paper on p. 708 ff.Read the full text of the article at 10.1002/open.201500109.

11.
ChemistryOpen ; 4(6): 708-16, 2015 12.
Artigo em Inglês | MEDLINE | ID: mdl-27308196

RESUMO

Gold nanoparticles decorated with full-length sialic acid terminated complex bi-antennary N-glycans, synthesized with glycans isolated from egg yolk, were used as a sensor for the detection of both recombinant hemagglutinin (HA) and whole influenza A virus particles of the H1N1 subtype. Nanoparticle aggregation was induced by interaction between the sialic acid termini of the glycans attached to gold and the multivalent sialic acid binding sites of HA. Both dynamic light scattering (DLS) and UV/Vis spectroscopy demonstrated the efficiency of the sensor, which could detect viral HA at nanomolar concentrations and revealed a linear relationship between the extent of nanoparticle aggregation and the concentration of HA. UV/Vis studies also showed that these nanoparticles can selectively detect an influenza A virus strain that preferentially binds sialic acid terminated glycans with α(2→6) linkages over a strain that prefers glycans with terminal α(2→3)-linked sialic acids.

12.
Cell Rep ; 12(4): 610-21, 2015 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-26190111

RESUMO

Akt is frequently activated in human cancers. However, it is unknown whether systemic inhibition of a single Akt isoform could regress cancer progression in cancers that are not driven by Akt activation. We systemically deleted Akt1 after tumor onset in p53(-/-) mice, which develop tumors independently of Akt activation. Systemic Akt1 deletion regresses thymic lymphoma in p53(-/-) mice emulating p53 restoration. Furthermore, pharmacological inhibition of Akt selectively kills thymic lymphoma cells and not primary thymocytes. Mechanistically, Akt1 inhibition in p53(-/-) thymic lymphoma inhibits Skp2 expression and induces FasL, which is the primary cause of cell death. Skp2 exerts resistance to cell death by antagonizing the induction of FasL and reducing FAS expression, which is linked to cyclin D1 expression. The results established a paradigm whereby systemic Akt1 inhibition is sufficient to regress tumors that are not driven by Akt activation and a mechanism of cell survival by Skp2.


Assuntos
Longevidade , Linfoma/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Timócitos/metabolismo , Proteína Supressora de Tumor p53/genética , Animais , Apoptose , Linhagem Celular Tumoral , Proteína Ligante Fas/metabolismo , Humanos , Linfoma/patologia , Camundongos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Quinases Associadas a Fase S/genética , Proteínas Quinases Associadas a Fase S/metabolismo , Timócitos/patologia , Proteína Supressora de Tumor p53/metabolismo
13.
BMJ Case Rep ; 20142014 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-24789157

RESUMO

Disturbances of tooth development may result in anomalies which appear in the form of swelling of the overlying mucosa of the erupting deciduous or permanent teeth, mostly in children. Eruption cyst (EC), a benign cyst is one such lesion associated with erupting teeth. ECs usually present as solitary swellings on the alveolar ridge mucosa, whereas multiple ECs presenting simultaneously or in short intervals are unusual. Here, we present a rare case of four large bilateral ECs presenting with swellings and pain in the posterior region of each quadrant in the mouth. The treatment included surgical excision under general anaesthesia and exposure of the unerupted primary teeth.


Assuntos
Doenças Mandibulares/cirurgia , Doenças Maxilares/cirurgia , Cistos Odontogênicos/cirurgia , Erupção Dentária , Seguimentos , Humanos , Lactente , Masculino , Doenças Mandibulares/diagnóstico , Doenças Maxilares/diagnóstico , Dente Molar , Cistos Odontogênicos/diagnóstico , Procedimentos Cirúrgicos Bucais/métodos , Medição de Risco , Índice de Gravidade de Doença , Resultado do Tratamento
14.
Eur J Med Chem ; 87: 274-83, 2014 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-25261825

RESUMO

A series of 2-(4-benzoyl-phenoxy)-N-(4-phenyl-thiazol-2-yl)-acetamides (10a-n) were synthesized by multistep reaction sequence and all the compounds were well characterized for structural elucidation. The in vitro cytotoxicity of compounds 10a-n was evaluated against EAC and DLA cell lines using trypan blue dye exclusion method. Further MTT assay and LDH release assay, followed by in vivo studies on murine model were also evaluated. The compound 10h with a methyl and fluoro groups at benzophenone moiety and methoxy group at phenyl ring was in a leading position to exhibit the promising antiproliferative effect through translational VEGF-A inhibition.


Assuntos
Benzofenonas/síntese química , Benzofenonas/farmacologia , Desenho de Fármacos , Tiazóis/química , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Animais , Benzofenonas/química , Linhagem Celular Tumoral , Técnicas de Química Sintética , Progressão da Doença , Humanos , Masculino , Camundongos , Relação Estrutura-Atividade , Ensaios Antitumorais Modelo de Xenoenxerto
15.
Life Sci ; 93(23): 904-11, 2013 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-24135459

RESUMO

AIM: The development of anticancer drugs with specific targets is of prime importance in modern biology. This study investigates the angiopreventive and in vivo tumor inhibition activities of novel synthetic benzophenone-benzimidazole analogs. MAIN METHODS: The multistep synthesis of novel benzophenone-benzimidazole analogs (8a-n) allowing substitution with methoxy, methyl and halogen groups at different positions on the identical chemical backbone and the variations in the number of substituents were synthesized and characterized. The newly synthesized compounds were further evaluated for cytotoxic and antiproliferative effects against Ehrlich ascites carcinoma (EAC) cells. The potent lead compounds were further assessed for antiangiogenic effects in a CAM model and a tumor-induced vasculature in vivo model. The effect of angioprevention on tumor growth was verified in a mouse model. KEY FINDINGS: The cytotoxicity studies revealed that compounds 8f and 8n are strongly cytotoxic. Analyzing the structure-activity relationship, we found that an increase in the number of methyl groups in addition to methoxy substitution at the para position of the benzoyl ring in compound 8n resulted in higher potency compared to 8f. Furthermore, neovessel formation in in vivo systems, such as the chorioallantoic membrane (CAM) and tumor-induced mice peritoneum models, was significantly suppressed and reflected the tumor inhibition observed in mice. SIGNIFICANCE: These results suggest the potential clinical application of compound 8n as an antiangiogenic drug for cancer therapy.


Assuntos
Inibidores da Angiogênese/farmacologia , Antineoplásicos/farmacologia , Benzimidazóis/farmacologia , Benzofenonas/farmacologia , Carcinoma de Ehrlich/tratamento farmacológico , Inibidores da Angiogênese/síntese química , Inibidores da Angiogênese/química , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Benzimidazóis/síntese química , Benzimidazóis/química , Benzofenonas/síntese química , Benzofenonas/química , Carcinoma de Ehrlich/irrigação sanguínea , Carcinoma de Ehrlich/patologia , Proliferação de Células/efeitos dos fármacos , Galinhas , Membrana Corioalantoide/irrigação sanguínea , Membrana Corioalantoide/efeitos dos fármacos , Camundongos , Neovascularização Patológica/tratamento farmacológico , Neovascularização Patológica/patologia , Peritônio/irrigação sanguínea , Peritônio/efeitos dos fármacos , Relação Estrutura-Atividade
16.
Cancer Cell ; 24(2): 213-228, 2013 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-23911236

RESUMO

Accelerated glucose metabolism is a common feature of cancer cells. Hexokinases catalyze the first committed step of glucose metabolism. Hexokinase 2 (HK2) is expressed at high level in cancer cells, but only in a limited number of normal adult tissues. Using Hk2 conditional knockout mice, we showed that HK2 is required for tumor initiation and maintenance in mouse models of KRas-driven lung cancer, and ErbB2-driven breast cancer, despite continued HK1 expression. Similarly, HK2 ablation inhibits the neoplastic phenotype of human lung and breast cancer cells in vitro and in vivo. Systemic Hk2 deletion is therapeutic in mice bearing lung tumors without adverse physiological consequences. Hk2 deletion in lung cancer cells suppressed glucose-derived ribonucleotides and impaired glutamine-derived carbon utilization in anaplerosis.


Assuntos
Neoplasias da Mama/enzimologia , Hexoquinase/metabolismo , Neoplasias Pulmonares/enzimologia , Animais , Neoplasias da Mama/genética , Linhagem Celular Tumoral , Modelos Animais de Doenças , Feminino , Glicólise , Hexoquinase/biossíntese , Hexoquinase/genética , Humanos , Neoplasias Pulmonares/genética , Masculino , Camundongos , Camundongos Knockout , Transplante Heterólogo
17.
Dev Cell ; 18(4): 592-604, 2010 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-20412774

RESUMO

FoxO transcription factors and TORC1 are conserved downstream effectors of Akt. Here, we unraveled regulatory circuits underlying the interplay between Akt, FoxO, and mTOR. Activated FoxO1 inhibits mTORC1 by TSC2-dependent and TSC2-independent mechanisms. First, FoxO1 induces Sestrin3 (Sesn3) gene expression. Sesn3, in turn, inhibits mTORC1 activity in Tsc2-proficient cells. Second, FoxO1 elevates the expression of Rictor, leading to increased mTORC2 activity that consequently activates Akt. In Tsc2-deficient cells, the elevation of Rictor by FoxO increases mTORC2 assembly and activity at the expense of mTORC1, thereby activating Akt while inhibiting mTORC1. FoxO may act as a rheostat that maintains homeostatic balance between Akt and mTOR complexes' activities. In response to physiological stresses, FoxO maintains high Akt activity and low mTORC1 activity. Thus, under stress conditions, FoxO inhibits the anabolic activity of mTORC1, a major consumer of cellular energy, while activating Akt, which increases cellular energy metabolism, thereby maintaining cellular energy homeostasis.


Assuntos
Proteínas de Transporte/metabolismo , Fatores de Transcrição Forkhead/metabolismo , Regulação Enzimológica da Expressão Gênica , Proteínas de Choque Térmico/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fatores de Transcrição/metabolismo , Fatores de Transcrição/fisiologia , Animais , Sequência de Bases , Ativação Enzimática , Proteína Forkhead Box O3 , Humanos , Alvo Mecanístico do Complexo 1 de Rapamicina , Camundongos , Dados de Sequência Molecular , Complexos Multiproteicos , Proteínas , Proteína Companheira de mTOR Insensível à Rapamicina , Homologia de Sequência do Ácido Nucleico , Serina-Treonina Quinases TOR , Proteína 2 do Complexo Esclerose Tuberosa , Proteínas Supressoras de Tumor/metabolismo
18.
Mol Cell Biol ; 29(18): 5136-47, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19620286

RESUMO

The current concept is that Tsc-deficient cells are sensitized to apoptosis due to the inhibition of Akt activity by the negative feedback mechanism induced by the hyperactive mTORC1. Unexpectedly, however, we found that Tsc1/2-deficient cells exhibit increased resistance to serum deprivation-induced apoptosis. mTORC1 hyperactivity contributes to the apoptotic resistance of serum-deprived Tsc1/2-deficient cells in part by increasing the growth factor-independent expression of hexokinase II (HKII) and GLUT1. mTORC1-mediated increase in hypoxia-inducible factor 1alpha (HIF1alpha) abundance, which occurs in the absence of serum in normoxic Tsc2-deficient cells, contributes to these changes. Increased HIF1alpha abundance in these cells is attributed to both an increased level and the sustained translation of HIF1alpha mRNA. Sustained glycogen synthase kinase 3beta inhibition and Mcl-1 expression also contribute to the apoptotic resistance of Tsc2-deficient cells to serum deprivation. The inhibition of mTORC1 activity by either rapamycin or Raptor knockdown cannot resensitize these cells to serum deprivation-induced apoptosis because of elevated Akt activity that is an indirect consequence of mTORC1 inhibition. However, the increased HIF1alpha abundance and the maintenance of Mcl-1 protein expression in serum-deprived Tsc2(-/)(-) cells are dependent largely on the hyperactive eIF4E in these cells. Consistently, the reduction of eIF4E levels abrogates the resistance of Tsc2(-/)(-) cells to serum deprivation-induced apoptosis.


Assuntos
Apoptose , Transportador de Glucose Tipo 1/metabolismo , Quinase 3 da Glicogênio Sintase/antagonistas & inibidores , Hexoquinase/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Soro/metabolismo , Fatores de Transcrição/metabolismo , Animais , Apoptose/efeitos dos fármacos , Embrião de Mamíferos/citologia , Ativação Enzimática/efeitos dos fármacos , Fator de Iniciação 4E em Eucariotos/metabolismo , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/enzimologia , Glicogênio Sintase Quinase 3 beta , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/deficiência , Alvo Mecanístico do Complexo 1 de Rapamicina , Camundongos , Complexos Multiproteicos , Proteína de Sequência 1 de Leucemia de Células Mieloides , Fosforilação/efeitos dos fármacos , Proteínas , Proteínas Proto-Oncogênicas c-akt/metabolismo , Sirolimo/farmacologia , Serina-Treonina Quinases TOR , Fatores de Transcrição/antagonistas & inibidores , Proteína 1 do Complexo Esclerose Tuberosa , Proteína 2 do Complexo Esclerose Tuberosa , Proteínas Supressoras de Tumor/deficiência , Proteínas Supressoras de Tumor/metabolismo , Proteína de Morte Celular Associada a bcl/metabolismo
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