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1.
Cell Rep ; 43(1): 113557, 2024 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-38113141

RESUMO

Metabolic reprogramming in pediatric diffuse midline glioma is driven by gene expression changes induced by the hallmark histone mutation H3K27M, which results in aberrantly permissive activation of oncogenic signaling pathways. Previous studies of diffuse midline glioma with altered H3K27 (DMG-H3K27a) have shown that the RAS pathway, specifically through its downstream kinase, extracellular-signal-related kinase 5 (ERK5), is critical for tumor growth. Further downstream effectors of ERK5 and their role in DMG-H3K27a metabolic reprogramming have not been explored. We establish that ERK5 is a critical regulator of cell proliferation and glycolysis in DMG-H3K27a. We demonstrate that ERK5 mediates glycolysis through activation of transcription factor MEF2A, which subsequently modulates expression of glycolytic enzyme PFKFB3. We show that in vitro and mouse models of DMG-H3K27a are sensitive to the loss of PFKFB3. Multi-targeted drug therapy against the ERK5-PFKFB3 axis, such as with small-molecule inhibitors, may represent a promising therapeutic approach in patients with pediatric diffuse midline glioma.


Assuntos
Glioma , Histonas , Animais , Criança , Humanos , Camundongos , MAP Quinases Reguladas por Sinal Extracelular , Glioma/genética , Glicólise , Histonas/genética , Fosfofrutoquinase-2 , Monoéster Fosfórico Hidrolases , Transdução de Sinais
2.
Mol Oncol ; 17(9): 1821-1843, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37014128

RESUMO

In previous studies, we demonstrated that panobinostat, a histone deacetylase inhibitor, and bortezomib, a proteasomal inhibitor, displayed synergistic therapeutic activity against pediatric and adult high-grade gliomas. Despite the remarkable initial response to this combination, resistance emerged. Here, in this study, we aimed to investigate the molecular mechanisms underlying the anticancer effects of panobinostat and marizomib, a brain-penetrant proteasomal inhibitor, and the potential for exploitable vulnerabilities associated with acquired resistance. RNA sequencing followed by gene set enrichment analysis (GSEA) was employed to compare the molecular signatures enriched in resistant compared with drug-naïve cells. The levels of adenosine 5'-triphosphate (ATP), nicotinamide adenine dinucleotide (NAD)+ content, hexokinase activity, and tricarboxylic acid (TCA) cycle metabolites required for oxidative phosphorylation to meet their bioenergetic needs were analyzed. Here, we report that panobinostat and marizomib significantly depleted ATP and NAD+ content, increased mitochondrial permeability and reactive oxygen species generation, and promoted apoptosis in pediatric and adult glioma cell lines at initial treatment. However, resistant cells exhibited increased levels of TCA cycle metabolites, which required for oxidative phosphorylation to meet their bioenergetic needs. Therefore, we targeted glycolysis and the electron transport chain (ETC) with small molecule inhibitors, which displayed substantial efficacy, suggesting that resistant cell survival is dependent on glycolytic and ETC complexes. To verify these observations in vivo, lonidamine, an inhibitor of glycolysis and mitochondrial function, was chosen. We produced two diffuse intrinsic pontine glioma (DIPG) models, and lonidamine treatment significantly increased median survival in both models, with particularly dramatic effects in panobinostat- and marizomib-resistant cells. These data provide new insights into mechanisms of treatment resistance in gliomas.


Assuntos
Glioma , NAD , Humanos , Adulto , Criança , Panobinostat/farmacologia , Panobinostat/uso terapêutico , Glioma/genética , Inibidores de Proteassoma/farmacologia , Mitocôndrias/metabolismo , Linhagem Celular Tumoral
4.
Nat Cancer ; 3(5): 629-648, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35422502

RESUMO

Diffuse midline gliomas (DMGs) bearing driver mutations of histone 3 lysine 27 (H3K27M) are incurable brain tumors with unique epigenomes. Here, we generated a syngeneic H3K27M mouse model to study the amino acid metabolic dependencies of these tumors. H3K27M mutant cells were highly dependent on methionine. Interrogating the methionine cycle dependency through a short-interfering RNA screen identified the enzyme methionine adenosyltransferase 2A (MAT2A) as a critical vulnerability in these tumors. This vulnerability was not mediated through the canonical mechanism of MTAP deletion; instead, DMG cells have lower levels of MAT2A protein, which is mediated by negative feedback induced by the metabolite decarboxylated S-adenosyl methionine. Depletion of residual MAT2A induces global depletion of H3K36me3, a chromatin mark of transcriptional elongation perturbing oncogenic and developmental transcriptional programs. Moreover, methionine-restricted diets extended survival in multiple models of DMG in vivo. Collectively, our results suggest that MAT2A presents an exploitable therapeutic vulnerability in H3K27M gliomas.


Assuntos
Neoplasias Encefálicas , Glioma , Metionina Adenosiltransferase/metabolismo , Animais , Neoplasias Encefálicas/genética , Epigenoma , Glioma/genética , Histonas/genética , Metionina/genética , Camundongos
5.
Mol Oncol ; 16(1): 219-249, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34058053

RESUMO

Acquired resistance to conventional chemotherapeutic agents limits their effectiveness and can cause cancer treatment to fail. Because enzymes in the aurora kinase family are vital regulators of several mitotic events, we reasoned that targeting these kinases with tozasertib, a pan-aurora kinase inhibitor, would not only cause cytokinesis defects, but also induce cell death in high-grade pediatric and adult glioma cell lines. We found that tozasertib induced cell cycle arrest, increased mitochondrial permeability and reactive oxygen species generation, inhibited cell growth and migration, and promoted cellular senescence and pro-apoptotic activity. However, sustained exposure to tozasertib at clinically relevant concentrations conferred resistance, which led us to examine the mechanistic basis for the emergence of drug resistance. RNA-sequence analysis revealed a significant upregulation of the gene encoding pyruvate dehydrogenase kinase isoenzyme 4 (PDK4), a pyruvate dehydrogenase (PDH) inhibitory kinase that plays a crucial role in the control of metabolic flexibility under various physiological conditions. Upregulation of PDK1, PDK2, PDK3, or PDK4 protein levels was positively correlated with tozasertib-induced resistance through inhibition of PDH activity. Tozasertib-resistant cells exhibited increased mitochondrial mass as measured by 10-N-nonyl-Acridine Orange. Inhibition of PDK with dichloroacetate resulted in increased mitochondrial permeability and cell death in tozasertib-resistant glioma cell lines. Based on these results, we believe that PDK is a selective target for the tozasertib resistance phenotype and should be considered for further preclinical evaluations.


Assuntos
Glioma , Ácido Pirúvico , Aurora Quinases , Criança , Glioma/tratamento farmacológico , Glioma/genética , Humanos , Isoenzimas/genética , Oxirredutases , Piperazinas , Proteínas Serina-Treonina Quinases , Piruvato Desidrogenase Quinase de Transferência de Acetil
6.
Mol Cancer Res ; 18(7): 1004-1017, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32238439

RESUMO

To improve therapeutic responses in patients with glioma, new combination therapies that exploit a mechanistic understanding of the inevitable emergence of drug resistance are needed. Intratumoral heterogeneity enables a low barrier to resistance in individual patients with glioma. We reasoned that targeting two or more fundamental processes that gliomas are particularly dependent upon could result in pleiotropic effects that would reduce the diversity of resistant subpopulations allowing convergence to a more robust therapeutic strategy. In contrast to the cytostatic responses observed with each drug alone, the combination of the histone deacetylase inhibitor panobinostat and the proteasome inhibitor bortezomib synergistically induced apoptosis of adult and pediatric glioma cell lines at clinically achievable doses. Resistance that developed was examined using RNA-sequencing and pharmacologic screening of resistant versus drug-naïve cells. Quinolinic acid phosphoribosyltransferase (QPRT), the rate-determining enzyme for de novo synthesis of NAD+ from tryptophan, exhibited particularly high differential gene expression in resistant U87 cells and protein expression in all resistant lines tested. Reducing QPRT expression reversed resistance, suggesting that QPRT is a selective and targetable dependency for the panobinostat-bortezomib resistance phenotype. Pharmacologic inhibition of either NAD+ biosynthesis or processes such as DNA repair that consume NAD+ or their simultaneous inhibition with drug combinations, specifically enhanced apoptosis in treatment-resistant cells. Concomitantly, de novo vulnerabilities to known drugs were observed. IMPLICATIONS: These data provide new insights into mechanisms of treatment resistance in gliomas, hold promise for targeting recurrent disease, and provide a potential strategy for further exploration of next-generation inhibitors.


Assuntos
Bortezomib/farmacologia , Resistencia a Medicamentos Antineoplásicos , Glioma/genética , Panobinostat/farmacologia , Pentosiltransferases/genética , Regulação para Cima , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Sinergismo Farmacológico , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Glioma/tratamento farmacológico , Glioma/metabolismo , Humanos , NAD/biossíntese , Pentosiltransferases/antagonistas & inibidores , Pentosiltransferases/metabolismo , Interferência de RNA , Análise de Sequência de RNA
7.
Mol Carcinog ; 57(4): 469-482, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29240261

RESUMO

In the present study, we investigated the effect of CDK inhibitors (ribociclib, palbociclib, seliciclib, AZD5438, and dinaciclib) on malignant human glioma cells for cell viability, apoptosis, oxidative stress, and mitochondrial function using various assays. None of the CDK inhibitors induced cell death at a clinically relevant concentration. However, low nanomolar concentrations of dinaciclib showed higher cytotoxic activity against Bcl-xL silenced cells in a time- and concentration-dependent manner. This effect was not seen with other CDK inhibitors. The apoptosis-inducing capability of dinaciclib in Bcl-xL silenced cells was evidenced by cell shrinkage, mitochondrial dysfunction, DNA damage, and increased phosphatidylserine externalization. Dinaciclib was found to disrupt mitochondrial membrane potential, resulting in the release of cytochrome c, AIF, and smac/DIABLO into the cytoplasm. This was accompanied by the downregulation of cyclin-D1, D3, and total Rb. Dinaciclib caused cell cycle arrest in a time- and concentration-dependent manner and with accumulation of cells in the sub-G1 phase. Our results also revealed that dinaciclib, but not ribociclib or palbociclib or seliciclib or AZD5438 induced intrinsic apoptosis via upregulation of the levels of pro-apoptotic proteins (Bax and Bak), resulting in the activation of caspases and cleavage of PARP. We also found an additional mechanism for the dinaciclib-induced augmentation of apoptosis due to abrogation RAD51-cyclin D1 interaction, specifically proteolysis of the DNA repair proteins RAD51 and Ku80. Our results suggest that successfully interfering with Bcl-xL function may restore sensitivity to dinaciclib and could hold the promise for an effective combination therapeutic strategy.


Assuntos
Apoptose/efeitos dos fármacos , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Autoantígeno Ku/metabolismo , Mitocôndrias/metabolismo , Compostos de Piridínio/farmacologia , Rad51 Recombinase/metabolismo , Proteína bcl-X/metabolismo , Proteínas Reguladoras de Apoptose/metabolismo , Linhagem Celular Tumoral , Óxidos N-Cíclicos , Quinases Ciclina-Dependentes/antagonistas & inibidores , Glioma/genética , Glioma/metabolismo , Glioma/patologia , Humanos , Indolizinas , Autoantígeno Ku/genética , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Proteólise , Interferência de RNA , Rad51 Recombinase/genética , Regulação para Cima/efeitos dos fármacos , Proteína bcl-X/genética
8.
Mol Carcinog ; 56(4): 1251-1265, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-27805285

RESUMO

Because the anti-apoptotic protein Bcl-xL is overexpressed in glioma, one might expect that inhibiting or silencing this gene would promote tumor cell killing. However, our studies have shown that this approach has limited independent activity, but may tip the balance in favor of apoptosis induction in response to other therapeutic interventions. To address this issue, we performed a pharmacological screen using a panel of signaling inhibitors and chemotherapeutic agents in Bcl-xL silenced cells. Although limited apoptosis induction was observed with a series of inhibitors for receptor tyrosine kinases, PKC inhibitors, Src family members, JAK/STAT, histone deacetylase, the PI3K/Akt/mTOR pathway, MAP kinase, CDK, heat shock proteins, proteasomal processing, and various conventional chemotherapeutic agents, we observed a dramatic potentiation of apoptosis in Bcl-xL silenced cells with the survivin inhibitor, YM155. Treatment with YM155 increased the release of cytochrome c, smac/DIABLO and apoptosis inducing-factor, and promoted loss of mitochondrial membrane potential, activation of Bax, recruitment of LC3-II to the autophagosomes and apoptosis in Bcl-xL silenced cells. We also found an additional mechanism for the augmentation of apoptosis due to abrogation of DNA double-strand break repair mediated by Rad51 repression and enhanced accumulation of γH2AX. In summary, our observations may provide a new insight into the link between Bcl-xL and survivin inhibition for the development of novel therapies for glioma. © 2016 Wiley Periodicals, Inc.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Glioma/tratamento farmacológico , Imidazóis/farmacologia , Proteínas Inibidoras de Apoptose/antagonistas & inibidores , Naftoquinonas/farmacologia , Proteína bcl-X/genética , Autofagia/efeitos dos fármacos , Linhagem Celular Tumoral , Citocromos c/metabolismo , Inativação Gênica , Glioma/genética , Glioma/metabolismo , Glioma/patologia , Humanos , Proteínas Inibidoras de Apoptose/metabolismo , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Survivina , Serina-Treonina Quinases TOR/metabolismo
9.
J Pharmacol Exp Ther ; 356(2): 354-65, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26585571

RESUMO

The prognosis for malignant glioma, the most common brain tumor, is still poor, underscoring the need to develop novel treatment strategies. Because glioma cells commonly exhibit genomic alterations involving genes that regulate cell-cycle control, there is a strong rationale for examining the potential efficacy of strategies to counteract this process. In this study, we examined the antiproliferative effects of the cyclin-dependent kinase inhibitor dinaciclib in malignant human glioma cell lines, with intact, deleted, or mutated p53 or phosphatase and tensin homolog on chromosome 10; intact or deleted or p14ARF or wild-type or amplified epidermal growth factor receptor. Dinaciclib inhibited cell proliferation and induced cell-cycle arrest at the G2/M checkpoint, independent of p53 mutational status. In a standard 72-hour 3-[4,5-dimethylthiazol- 2yl]-5-[3-carboxymethoxyphenyl]-2-[4-sulfophenyl]-2H, tetrazolium (MTS) assay, at clinically relevant concentrations, dose-dependent antiproliferative effects were observed, but cell death was not induced. Moreover, the combination of conventional chemotherapeutic agents and various growth-signaling inhibitors with dinaciclib did not yield synergistic cytotoxicity. In contrast, combination of the Bcl-2/Bcl-xL inhibitors ABT-263 (4-[4-[[2-(4-chlorophenyl)-5,5-dimethylcyclohexen-1-yl]methyl]piperazin-1-yl]-N-[4-[[(2R)-4-morpholin-4-yl-1-phenylsulfanylbutan-2-yl]amino]-3-(trifluoromethylsulfonyl)phenyl]sulfonylbenzamide) or ABT-737 (4-[4-[[2-(4-chlorophenyl)phenyl]methyl]piperazin-1-yl]-N-[4-[[(2R)-4-(dimethylamino)-1-phenylsulfanylbutan-2-yl]amino]-3-nitrophenyl]sulfonylbenzamide) with dinaciclib potentiated the apoptotic response induced by each single drug. The synergistic killing by ABT-737 with dinaciclib led to cell death accompanied by the hallmarks of apoptosis, including an early loss of the mitochondrial transmembrane potential; the release of cytochrome c, smac/DIABLO, and apoptosis-inducing factor; phosphatidylserine exposure on the plasma membrane surface and activation of caspases and poly ADP-ribose polymerase. Mechanistic studies revealed that dinaciclib promoted proteasomal degradation of Mcl-1. These observations may have important clinical implications for the design of experimental treatment protocols for malignant human glioma.


Assuntos
Compostos de Bifenilo/administração & dosagem , Compostos Bicíclicos Heterocíclicos com Pontes/administração & dosagem , Quinases Ciclina-Dependentes/antagonistas & inibidores , Glioma/metabolismo , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Nitrofenóis/administração & dosagem , Complexo de Endopeptidases do Proteassoma/metabolismo , Compostos de Piridínio/administração & dosagem , Sulfonamidas/administração & dosagem , Morte Celular/efeitos dos fármacos , Morte Celular/fisiologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/fisiologia , Óxidos N-Cíclicos , Quinases Ciclina-Dependentes/metabolismo , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Glioma/tratamento farmacológico , Humanos , Indolizinas , Piperazinas/administração & dosagem
10.
Int J Oncol ; 47(2): 506-16, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26044191

RESUMO

We previously observed that glioma cells are differentially sensitive to TRAIL-induced toxicity. Based on our observation that TRAIL-resistant glioma cell lines typically exhibited high levels of Akt activation, we hypothesized that inhibition of Akt signaling using the PI3 kinase inhibitor NVP-BKM120 could promote TRAIL-induced apoptosis in gliomas. We assessed this combination in established and primary cultured glioma cells. Combination treatment led to significant cellular death when compared to either drug alone, but had no effect in normal human astrocytes, and demonstrated activation of the caspase cascade. This enhanced apoptosis appears dependent upon the loss of mitochondrial membrane potential and the release of Smac/DIABLO, AIF and cytochrome c into the cytosol. The upregulation of Noxa and sequestration of Mcl-1 by Noxa were important factors for cell death. Knockdown of Noxa abrogated apoptosis and suggested dependency on Noxa in combination-induced apoptosis. BKM120 upregulated cell surface expression of death receptor 5 (DR5), but did not increase levels of the other major TRAIL receptor, death receptor 4 (DR4). This study demonstrates that antagonizing apoptosis-resistance pathways, such as the PI3/Akt pathway, in combination with death receptor activation, may induce cell death in TRAIL-resistant glioma.


Assuntos
Aminopiridinas/farmacologia , Antineoplásicos/farmacologia , Neoplasias Encefálicas/metabolismo , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Glioma/metabolismo , Morfolinas/farmacologia , Ligante Indutor de Apoptose Relacionado a TNF/farmacologia , Apoptose , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Neoplasias Encefálicas/tratamento farmacológico , Linhagem Celular Tumoral , Sinergismo Farmacológico , Glioma/tratamento farmacológico , Humanos , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Regulação para Cima
11.
Cancer Biol Ther ; 16(2): 233-43, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25482928

RESUMO

Because STAT signaling is commonly activated in malignant gliomas as a result of constitutive EGFR activation, strategies for inhibiting the EGFR/JAK/STAT cascade are of significant interest. We, therefore, treated a panel of established glioma cell lines, including EGFR overexpressors, and primary cultures derived from patients diagnosed with glioblastoma with the JAK/STAT inhibitor cucurbitacin-I. Treatment with cucurbitacin-I depleted p-STAT3, p-STAT5, p-JAK1 and p-JAK2 levels, inhibited cell proliferation, and induced G2/M accumulation, DNA endoreduplication, and multipolar mitotic spindles. Longer exposure to cucurbitacin-I significantly reduced the number of viable cells and this decrease in viability was associated with cell death, as confirmed by an increase in the subG1 fraction. Our data also demonstrated that cucurbitacin-I strikingly downregulated Aurora kinase A, Aurora kinase B and survivin. We then searched for agents that exhibited a synergistic effect on cell death in combination with cucurbitacin-I. We found that cotreatment with cucurbitacin-I significantly increased Bcl(-)2/Bcl(-)xL family member antagonist ABT-737-induced cell death regardless of EGFR/PTEN/p53 status of malignant human glioma cell lines. Although >50% of the cucurbitacin-I plus ABT-737 treated cells were annexin V and propidium iodide positive, PARP cleavage or caspase activation was not observed. Pretreatment of z-VAD-fmk, a pan caspase inhibitor did not inhibit cell death, suggesting a caspase-independent mechanism of cell death. Genetic inhibition of Aurora kinase A or Aurora kinase B or survivin by RNA interference also sensitized glioma cells to ABT-737, suggesting a link between STAT activation and Aurora kinases in malignant gliomas.


Assuntos
Aurora Quinase A/antagonistas & inibidores , Aurora Quinase B/antagonistas & inibidores , Compostos de Bifenilo/farmacologia , Caspases/metabolismo , Ciclo Celular/efeitos dos fármacos , Glioma/metabolismo , Proteínas Inibidoras de Apoptose/antagonistas & inibidores , Nitrofenóis/farmacologia , Sulfonamidas/farmacologia , Triterpenos/farmacologia , Astrócitos/metabolismo , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/genética , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Receptores ErbB/genética , Receptores ErbB/metabolismo , Expressão Gênica , Genótipo , Glioma/genética , Glioma/patologia , Humanos , PTEN Fosfo-Hidrolase/genética , PTEN Fosfo-Hidrolase/metabolismo , Piperazinas/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacos , Survivina , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo
12.
J Neurooncol ; 120(3): 459-72, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25139025

RESUMO

We previously observed that glioma cells are differentially sensitive to ABT-737 and, when used as a single-agent, this drug failed to induce apoptosis. Identification of therapeutic strategies to enhance the efficacy of the Bcl-2 inhibitor ABT-737 in human glioma is of interest. Histone deacetylation inhibitors (HDACI) are currently being assessed clinically in patients with glioma, as regulation of epigenetic abnormalities is expected to produce pro-apoptotic effects. We hypothesized that co-treatment of glioma with a BH3-mimetic and HDACI may induce cellular death. We assessed the combination of ABT-737 and HDACI SAHA in established and primary cultured glioma cells. We found combination treatment led to significant cellular death when compared to either drug as single agent and demonstrated activation of the caspase cascade. This enhanced apoptosis also appears dependent upon the loss of mitochondrial membrane potential and the release of cytochrome c and AIF into the cytosol. The upregulation of Noxa, truncation of Bid, and activation of Bax caused by this combination were important factors for cell death and the increased levels of Noxa functioned to sequester Mcl-1. This combination was less effective in PTEN-deficient glioma cells. Both genetic and pharmacologic inactivation of the PI3K/Akt signaling pathway sensitized PTEN-deleted glioma cells to the combination. This study demonstrates that antagonizing apoptosis-resistance pathways, such as targeting the Bcl-2 family in combination with epigenetic modifiers, may induce cell death. These findings extend our previous observations that targeting the PI3K/Akt pathway may be additionally necessary to promote apoptosis in cancers lacking PTEN functionality.


Assuntos
Antineoplásicos/farmacologia , Compostos de Bifenilo/farmacologia , Glioma/tratamento farmacológico , Inibidores de Histona Desacetilases/farmacologia , Nitrofenóis/farmacologia , Sulfonamidas/farmacologia , Apoptose/efeitos dos fármacos , Fator de Indução de Apoptose/metabolismo , Proteína Agonista de Morte Celular de Domínio Interatuante com BH3/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Citocromos c/metabolismo , Quimioterapia Combinada , Glioma/genética , Glioma/patologia , Glioma/fisiopatologia , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/fisiologia , PTEN Fosfo-Hidrolase/deficiência , PTEN Fosfo-Hidrolase/genética , Piperazinas/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Regulação para Cima/efeitos dos fármacos , Proteína X Associada a bcl-2/metabolismo
13.
J Pharmacol Exp Ther ; 350(1): 22-35, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24741074

RESUMO

Identification of therapeutic strategies that might enhance the efficacy of B-cell lymphoma-2 (Bcl-2) inhibitor ABT-737 [N-{4-[4-(4-chloro-biphenyl-2-ylmethyl)-piperazin-1-yl]-benzoyl}-4-(3-dimethylamino-1-phenylsulfanylmethyl-propylamino)-3-nitro-benzenesulfonamide] is of great interest in many cancers, including glioma. Our recent study suggested that Akt is a crucial mediator of apoptosis sensitivity in response to ABT-737 in glioma cell lines. Inhibitors of phosphatidylinositol 3-kinase (PI3K)/Akt are currently being assessed clinically in patients with glioma. Because PI3K/Akt inhibition would be expected to have many proapoptotic effects, we hypothesized that there may be unique synergy between PI3K inhibitors and Bcl-2 homology 3 mimetics. Toward this end, we assessed the combination of the PI3K/Akt inhibitor NVP-BKM120 [5-(2,6-dimorpholinopyrimidin-4-yl)-4-(trifluoromethyl)pyridin-2-amine] and the Bcl-2 family inhibitor ABT-737 in established and primary cultured glioma cells. We found that the combined treatment with these agents led to a significant activation of caspase-8 and -3, PARP, and cell death, irrespective of PTEN status. The enhanced lethality observed with this combination also appears dependent on the loss of mitochondrial membrane potential and release of cytochrome c, smac/DIABLO, and apoptosis-inducing factor to the cytosol. Further study revealed that the upregulation of Noxa, truncation of Bid, and activation of Bax and Bak caused by these inhibitors were the key factors for the synergy. In addition, we demonstrated the release of proapoptotic proteins Bim and Bak from Mcl-1. We found defects in chromosome segregation leading to multinuclear cells and loss of colony-forming ability, suggesting the potential use of NVP-BKM120 as a promising agent to improve the anticancer activities of ABT-737.


Assuntos
Aminopiridinas/farmacologia , Antineoplásicos/farmacologia , Compostos de Bifenilo/toxicidade , Caspases/metabolismo , Dano ao DNA/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Morfolinas/farmacologia , Nitrofenóis/toxicidade , Inibidores de Fosfoinositídeo-3 Quinase , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Sulfonamidas/toxicidade , Fator de Indução de Apoptose/metabolismo , Proteínas Reguladoras de Apoptose , Proteína 11 Semelhante a Bcl-2 , Caspase 3/metabolismo , Caspase 8/metabolismo , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Segregação de Cromossomos/efeitos dos fármacos , Citocromos c/metabolismo , Sinergismo Farmacológico , Glioblastoma/enzimologia , Glioblastoma/genética , Glioblastoma/metabolismo , Glioblastoma/patologia , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Proteínas de Membrana , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Proteínas Mitocondriais/metabolismo , Piperazinas/toxicidade , Poli(ADP-Ribose) Polimerases/metabolismo , Cultura Primária de Células , Proteínas Proto-Oncogênicas , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteína Killer-Antagonista Homóloga a bcl-2/metabolismo , Proteína X Associada a bcl-2/metabolismo
14.
J Pharmacol Exp Ther ; 346(2): 201-10, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23740602

RESUMO

Induction of apoptosis by the death ligand tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising antitumor therapy. However, not all tumor cells are sensitive to TRAIL, highlighting the need for strategies to overcome TRAIL resistance. Inhibitor of apoptosis family member survivin is constitutively activated in various cancers and blocks apoptotic signaling. Recently, we demonstrated that YM-155 [3-(2-methoxyethyl)-2-methyl-4,9-dioxo-1-(pyrazin-2-ylmethyl)-4,9-dihydro-3H-naphtho[2,3-d]imidazol-1-ium bromide], a small molecule inhibitor, downregulates not only survivin in gliomas but also myeloid cell leukemia sequence 1 (Mcl-1), and it upregulates proapoptotic Noxa levels. Because Mcl-1 and survivin are critical mediators of resistance to various anticancer therapies, we questioned whether YM-155 could sensitize resistant glioma cells to TRAIL. To address this hypothesis, we combined YM-155 with TRAIL and examined the effects on cell survival and apoptotic signaling. TRAIL or YM-155 individually induced minimal killing in highly resistant U373 and LNZ308 cell lines, but combining TRAIL with YM-155 triggered a synergistic proapoptotic response, mediated through mitochondrial dysfunction via activation of caspases-8, -9, -7, -3, poly-ADP-ribose polymerase, and Bid. Apoptosis induced by combination treatments was blocked by caspase-8 and pan-caspase inhibitors. In addition, knockdown of Mcl-1 by RNA interference overcame apoptotic resistance to TRAIL. Conversely, silencing Noxa by RNA interference reduced the combined effects of YM-155 and TRAIL on apoptosis. Mechanistically, these findings indicate that YM-155 plays a role in counteracting glioma cell resistance to TRAIL-induced apoptosis by downregulating Mcl-1 and survivin and amplifying mitochondrial signaling through intrinsic and extrinsic apoptotic pathways. The significantly enhanced antitumor activity of the combination of YM-155 and TRAIL may have applications for therapy of malignant glioma.


Assuntos
Apoptose , Glioma/patologia , Imidazóis/farmacologia , Proteínas Inibidoras de Apoptose/antagonistas & inibidores , Mitocôndrias/metabolismo , Naftoquinonas/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular , Regulação para Baixo , Resistencia a Medicamentos Antineoplásicos , Sinergismo Farmacológico , Técnicas de Silenciamento de Genes , Glioma/metabolismo , Humanos , Proteínas Inibidoras de Apoptose/metabolismo , Proteína de Sequência 1 de Leucemia de Células Mieloides , Conformação Proteica , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Recombinantes/farmacologia , Survivina , Ligante Indutor de Apoptose Relacionado a TNF/farmacologia , Proteína Killer-Antagonista Homóloga a bcl-2/metabolismo , Proteína X Associada a bcl-2/metabolismo
15.
Mol Cancer Ther ; 12(3): 326-38, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23325792

RESUMO

Antiapoptotic proteins are commonly overexpressed in gliomas, contributing to therapeutic resistance. We recently reported that clinically achievable concentrations of the Bcl-2/Bcl-xL inhibitor ABT-737 failed to induce apoptosis in glioma cells, with persistent expression of survivin and Mcl-1. To address the role of these mediators in glioma apoptosis resistance, we analyzed the effects of YM-155, a survivin suppressant, on survival on a panel of glioma cell lines. YM-155 inhibited cell growth and downregulated survivin and Mcl-1 in a dose- and cell line-dependent manner. While U373, LN18, LNZ428, T98G, LN229, and LNZ308 cells exhibited an IC(50) of 10 to 75 nmol/L, A172 cells were resistant (IC(50) ∼ 250 nmol/L). No correlation was found between sensitivity to YM-155 and baseline expression of survivin or cIAP-1/cIAP-2/XIAP. However, strong correlation was observed between EGF receptor (EGFR) activation levels and YM-155 response, which was confirmed using EGFR-transduced versus wild-type cells. Because we postulated that decreasing Mcl-1 expression may enhance glioma sensitivity to ABT-737, we examined whether cotreatment with YM-155 promoted ABT-737 efficacy. YM-155 synergistically enhanced ABT-737-induced cytotoxicity and caspase-dependent apoptosis. Downregulation of Mcl-1 using short hairpin RNA also enhanced ABT-737-inducing killing, confirming an important role for Mcl-1 in mediating synergism between ABT-737 and YM-155. As with YM-155 alone, sensitivity to YM-155 and ABT-737 inversely correlated with EGFR activation status. However, sensitivity could be restored in highly resistant U87-EGFRvIII cells by inhibition of EGFR or its downstream pathways, highlighting the impact of EGFR signaling on Mcl-1 expression and the relevance of combined targeted therapies to overcome the multiple resistance mechanisms of these aggressive tumors.


Assuntos
Compostos de Bifenilo/farmacologia , Neoplasias Encefálicas/tratamento farmacológico , Receptores ErbB/genética , Glioma/tratamento farmacológico , Imidazóis/farmacologia , Proteínas Inibidoras de Apoptose/genética , Naftoquinonas/farmacologia , Nitrofenóis/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/genética , Sulfonamidas/farmacologia , Apoptose/efeitos dos fármacos , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Linhagem Celular Tumoral , Regulação para Baixo , Resistencia a Medicamentos Antineoplásicos/genética , Receptores ErbB/antagonistas & inibidores , Receptores ErbB/metabolismo , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Glioma/genética , Glioma/metabolismo , Humanos , Proteínas Inibidoras de Apoptose/antagonistas & inibidores , Proteínas Inibidoras de Apoptose/metabolismo , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Proteína de Sequência 1 de Leucemia de Células Mieloides , Piperazinas/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Transdução de Sinais , Survivina , Proteína bcl-X/antagonistas & inibidores , Proteína bcl-X/genética , Proteína bcl-X/metabolismo
16.
Mol Carcinog ; 52(2): 118-33, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22086447

RESUMO

Glioblastomas are invasive tumors with poor prognosis despite current therapies. Histone deacetylase inhibitors (HDACIs) represent a class of agents that can modulate gene expression to reduce tumor growth, and we and others have noted some antiglioma activity from HDACIs, such as vorinostat, although insufficient to warrant use as monotherapy. We have recently demonstrated that proteasome inhibitors, such as bortezomib, dramatically sensitized highly resistant glioma cells to apoptosis induction, suggesting that proteasomal inhibition may be a promising combination strategy for glioma therapeutics. In this study, we examined whether bortezomib could enhance response to HDAC inhibition in glioma cells. Although primary cells from glioblastoma multiforme (GBM) patients and established glioma cell lines did not show significant induction of apoptosis with vorinostat treatment alone, the combination of vorinostat plus bortezomib significantly enhanced apoptosis. The enhanced efficacy was due to proapoptotic mitochondrial injury and increased generation of reactive oxygen species. Our results also revealed that combination of bortezomib with vorinostat enhanced apoptosis by increasing Mcl-1 cleavage, Noxa upregulation, Bak and Bax activation, and cytochrome c release. Further downregulation of Mcl-1 using shRNA enhanced cell killing by the bortezomib/vorinostat combination. Vorinostat induced a rapid and sustained phosphorylation of histone H2AX in primary GBM and T98G cells, and this effect was significantly enhanced by co-administration of bortezomib. Vorinostat/bortezomib combination also induced Rad51 downregulation, which plays an important role in the synergistic enhancement of DNA damage and apoptosis. The significantly enhanced antitumor activity that results from the combination of bortezomib and HDACIs offers promise as a novel treatment for glioma patients.


Assuntos
Apoptose/efeitos dos fármacos , Ácidos Borônicos/farmacologia , Neoplasias do Sistema Nervoso Central/tratamento farmacológico , Glioma/tratamento farmacológico , Glioma/genética , Ácidos Hidroxâmicos/farmacologia , Pirazinas/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Antineoplásicos/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Proteínas Reguladoras de Apoptose/metabolismo , Proteína 11 Semelhante a Bcl-2 , Ácidos Borônicos/administração & dosagem , Bortezomib , Linhagem Celular Tumoral , Neoplasias do Sistema Nervoso Central/genética , Neoplasias do Sistema Nervoso Central/metabolismo , Neoplasias do Sistema Nervoso Central/patologia , Citocromos c/metabolismo , Dano ao DNA/efeitos dos fármacos , Glioblastoma/tratamento farmacológico , Glioblastoma/patologia , Glioma/metabolismo , Glioma/patologia , Histonas/metabolismo , Humanos , Ácidos Hidroxâmicos/administração & dosagem , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Proteínas de Membrana/metabolismo , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Proteína de Sequência 1 de Leucemia de Células Mieloides , Fosforilação , Inibidores de Proteassoma/farmacologia , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Pirazinas/administração & dosagem , Células Tumorais Cultivadas , Vorinostat , Proteína Killer-Antagonista Homóloga a bcl-2/metabolismo , Proteína X Associada a bcl-2/metabolismo
17.
J Pharmacol Exp Ther ; 341(3): 859-72, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22393246

RESUMO

We observed that glioma cells are differentially sensitive to N-{4-[4-(4'-chloro-biphenyl-2-ylmethyl)-piperazin-1-yl]-benzoyl}-4-(3-dimethylamino-1-phenylsulfanylmethyl-propylamino)-3-nitro-benzenesulfonamide (ABT-737) and administration of ABT-737 at clinically achievable doses failed to induce apoptosis. Although elevated Bcl-2 levels directly correlated with sensitivity to ABT-737, overexpression of Bcl-2 did not influence sensitivity to ABT-737. To understand the molecular basis for variable and relatively modest sensitivity to the Bcl-2 homology domain 3 mimetic drug ABT-737, the abundance of Bcl-2 family members was assayed in a panel of glioma cell lines. Bcl-2 family member proteins, Bcl-xL, Bcl-w, Mcl-1, Bax, Bak, Bid, and Noxa, were found to be expressed ubiquitously at similar levels in all cell lines tested. We then examined the contribution of other apoptosis-resistance pathways to ABT-737 resistance. Bortezomib, an inhibitor of nuclear factor-kappaB (NF-κB), was found to enhance sensitivity of ABT-737 in phosphatase and tensin homolog on chromosome 10 (PTEN)-wild type, but not PTEN-mutated glioma cell lines. We therefore investigated the association between phosphatidylinositol 3-kinase (PI3K)/Akt activation and resistance to the combination of ABT-737 and bortezomib in PTEN-deficient glioma cells. Genetic and pharmacological inhibition of PI3K inhibition sensitized PTEN-deficient glioma cells to bortezomib- and ABT-737-induced apoptosis by increasing cleavage of Bid protein, activation and oligomerization of Bax, and loss of mitochondrial membrane potential. Our data further suggested that PI3K/Akt-dependent protection may occur upstream of the mitochondria. This study demonstrates that interference with multiple apoptosis-resistance signaling nodes, including NF-κB, Akt, and Bcl-2, may be required to induce apoptosis in highly resistant glioma cells, and therapeutic strategies that target the PI3K/Akt pathway may have a selective role for cancers lacking PTEN function.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Proteína Agonista de Morte Celular de Domínio Interatuante com BH3/metabolismo , Compostos de Bifenilo/farmacologia , Ácidos Borônicos/farmacologia , Doenças Mitocondriais/metabolismo , Nitrofenóis/farmacologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Pirazinas/farmacologia , Sulfonamidas/farmacologia , Proteína X Associada a bcl-2/metabolismo , Anexinas/metabolismo , Western Blotting , Bortezomib , Linhagem Celular Tumoral/metabolismo , Proliferação de Células , Sinergismo Farmacológico , Glioma/metabolismo , Glioma/patologia , Humanos , NF-kappa B/metabolismo , Piperazinas/farmacologia
18.
Mol Cancer Ther ; 10(1): 198-208, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21220502

RESUMO

Previous studies have shown that the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has significant apoptosis-inducing activity in some glioma cell lines, although many lines are either moderately or completely resistant, which has limited the therapeutic applicability of this agent. Because our recent studies showed that inhibition of proteasomal function may be independently active as an apoptosis-inducing stimulus in these tumors, we investigated the sensitivity of a panel of glioma cell lines (U87, T98G, U373, A172, LN18, LN229, LNZ308, and LNZ428) to TRAIL alone and in combination with the proteasome inhibitor bortezomib. Analysis of these cell lines revealed marked differences in their sensitivity to these treatments, with two (LNZ308 and U373) of the eight cell lines revealing no significant induction of cell death in response to TRAIL alone. No correlation was found between sensitivity of cells to TRAIL and expression of TRAIL receptors DR4, DR5, and decoy receptor DcR1, caspase 8, apoptosis inhibitory proteins XIAP, survivin, Mcl-1, Bcl-2, Bcl-Xl, and cFLIP. However, TRAIL-resistant cell lines exhibited a high level of basal NF-κB activity. Bortezomib was capable of potentiating TRAIL-induced apoptosis in TRAIL-resistant cells in a caspase-dependent fashion. Bortezomib abolished p65/NF-κB DNA-binding activity, supporting the hypothesis that inhibition of the NF-κB pathway is critical for the enhancement of TRAIL sensitization in glioma cells. Moreover, knockdown of p65/NF-κB by shRNA also enhanced TRAIL-induced apoptosis, indicating that p65/NF-κB may be important in mediating TRAIL sensitivity and the effect of bortezomib in promoting TRAIL sensitization and apoptosis induction.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Ácidos Borônicos/farmacologia , Glioma/genética , NF-kappa B/antagonistas & inibidores , Pirazinas/farmacologia , Ligante Indutor de Apoptose Relacionado a TNF/farmacologia , Apoptose/efeitos dos fármacos , Ácidos Borônicos/administração & dosagem , Bortezomib , Processos de Crescimento Celular/efeitos dos fármacos , Linhagem Celular Tumoral , DNA de Neoplasias/metabolismo , Sinergismo Farmacológico , Técnicas de Silenciamento de Genes , Glioma/metabolismo , Glioma/patologia , Humanos , NF-kappa B/metabolismo , Pirazinas/administração & dosagem , RNA Interferente Pequeno/administração & dosagem , RNA Interferente Pequeno/genética , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/genética , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Transdução de Sinais/efeitos dos fármacos , Ligante Indutor de Apoptose Relacionado a TNF/administração & dosagem , Fator de Transcrição RelA/genética , Transfecção
19.
J Carcinog ; 92010 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-20808823

RESUMO

BACKGROUND: Src family kinases (SFK) collectively regulate a variety of cellular functions in many cancer types, including proliferation, invasion, motility, survival, differentiation, and angiogenesis. Although Dasatinib (BMS-354825), an ATP-competitive, small molecule tyrosine kinase inhibitor, suppresses the activity of SFKs at nanomolar concentrations, IC50 values for antiproliferative effects in glioma cell lines were well above the clinically achievable range, suggesting the need to interfere with other components of receptor-induced downstream signaling in order to achieve an optimal therapeutic effect. MATERIALS AND METHODS: The cytotoxic effects of combining Src and STAT3 inhibition on glioma cell lines were evaluated using assays to measure cell proliferation, apoptosis and migration. Western blotting and immunocytochemistry was used to monitor its effects on cell signaling and morphology. RESULTS: Silencing Src and STAT3 expression each partially inhibited cell proliferation and migration. In addition, JSI-124 significantly enhanced the efficacy of dasatinib in vitro. Combination of dasatinib and JSI-124 achieved significant inhibition of migration in all cell lines, which correlated with the inhibition of Src and downstream mediators of adhesion (e.g. focal adhesion kinase). Cells exposed to dasatinib and JSI-124 exhibited morphological changes that were consistent with an upstream role for Src in regulating focal adhesion complexes. CONCLUSIONS: Targeting the Src and STAT pathways may contribute to the treatment of cancers that demonstrate increased levels of these signaling mediators, including malignant human glioma. Clinical studies in these tumor types are warranted.

20.
Int J Oncol ; 37(3): 633-43, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20664932

RESUMO

Glioblastoma multiforme represents a largely incurable tumor for which novel therapeutic strategies are required. We report the effect of NVP-AEW541, an inhibitor of insulin-like growth factor-I receptor (IGF-IR) kinase activity on growth and signaling in a panel of glioma cell lines. NVP-AEW541 blocked phosphorylation of IGF-IR in a dose- and time-dependent manner and inhibited proliferation and clonogenicity with median effective concentrations of 2.5-10 microM. NVP-AEW541 also induced loss of mitochondrial membrane potential and release of cytochrome c and apoptosis-inducing factor (AIF) from mitochondria. Because concentrations of NVP-AEW541 required to significantly inhibit glioma cell viability and downstream signaling also inhibited non-neoplastic astrocytes, we questioned whether differential efficacy could be enhanced by combination with inhibition of other tyrosine kinases dysregulated in gliomas. Dasatinib was selected as a combination agent based on its distinct inhibitory profile for other relevant signaling targets. Combined treatment with NVP-AEW541 and dasatinib induced significantly more apoptosis than either agent alone in glioma cells, but not non-neoplastic astrocytes, and synergistically inhibited clonogenic survival. Mechanistic studies indicated that combination of NVP-AEW541 and dasatinib significantly reduced pERK and pAkt and markedly increased AIF release, Bax oligomerization and loss of mitochondrial potential compared to each agent alone. Overexpression of Bcl-2 and Akt significantly attenuated NVP-AEW541 and dasatinib-induced Bax activation and cell death. Our data indicate that activation of Bax plays a critical role in mediating NVP-AEW541 and dasatinib-induced apoptosis, and suggest the potential value of combining IGFR inhibition with other classes of tyrosine kinase inhibitors to potentiate therapeutic efficacy.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Apoptose/efeitos dos fármacos , Glioblastoma/tratamento farmacológico , Mitocôndrias/efeitos dos fármacos , Pirimidinas/farmacologia , Pirróis/farmacologia , Tiazóis/farmacologia , Proteína X Associada a bcl-2/metabolismo , Apoptose/fisiologia , Ciclo Celular/efeitos dos fármacos , Proteínas de Ciclo Celular/metabolismo , Processos de Crescimento Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Dasatinibe , Sinergismo Farmacológico , Imunofluorescência , Glioblastoma/metabolismo , Glioblastoma/patologia , Humanos , Mitocôndrias/fisiologia , Fosforilação/efeitos dos fármacos , Inibidores de Proteínas Quinases/administração & dosagem , Inibidores de Proteínas Quinases/farmacologia , Pirimidinas/administração & dosagem , Pirróis/administração & dosagem , Transdução de Sinais/efeitos dos fármacos , Tiazóis/administração & dosagem , Transfecção
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