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1.
J Pathol ; 236(4): 479-90, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25875314

RESUMO

Chronic inflammation is a leading cause of neoplastic transformation in many human cancers and especially in colon cancer (CC), in part due to tumour promotion by nitric oxide (NO) generated at inflammatory sites. It has also been suggested that high NO synthesis, secondary to inducible NO synthase (iNOS) expression, is a distinctive feature of cancer stem cells (CSCs), a small subset of tumour cells with self-renewal capacity. In this study we explored the contribution of NO to the development of colon CSC features and evaluated potential strategies to treat CC by modulating NO production. Our data show an integral role for endogenous NO and iNOS activity in the biology of colon CSCs. Indeed, colon CSCs with high endogenous NO production (NO(high)) displayed higher tumourigenic abilities than NO(low) fractions. The blockade of endogenous NO availability, using either a specific iNOS inhibitor or a genetic knock-down of iNOS, resulted in a significant reduction of colon CSC tumourigenic capacities in vitro and in vivo. Interestingly, analysis of genes altered by iNOS-directed shRNA showed that the knockdown of iNOS expression was associated with a significant down-regulation of signalling pathways involved in stemness and tumour progression in colon CSCs. These findings confirm that endogenous NO plays an important role in defining the stemness properties of colon CSCs through cross-regulation of several cellular signalling pathways. This discovery could shed light on the mechanisms by which NO induces the growth and invasiveness of CC, providing new insights into the link between inflammation and colon tumourigenesis.


Assuntos
Neoplasias Colorretais/enzimologia , Células-Tronco Neoplásicas/enzimologia , Óxido Nítrico Sintase Tipo II/metabolismo , Óxido Nítrico/metabolismo , Antígeno AC133 , Animais , Antígenos CD/metabolismo , Antineoplásicos/farmacologia , Biomarcadores Tumorais/metabolismo , Células CACO-2 , Proliferação de Células , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Inibidores Enzimáticos/farmacologia , Regulação Enzimológica da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Glicoproteínas/metabolismo , Células HCT116 , Células HEK293 , Células HT29 , Humanos , Camundongos Nus , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/patologia , Óxido Nítrico Sintase Tipo II/antagonistas & inibidores , Óxido Nítrico Sintase Tipo II/genética , Peptídeos/metabolismo , Interferência de RNA , Transdução de Sinais , Fatores de Tempo , Transfecção , Carga Tumoral , Regulação para Cima , Ensaios Antitumorais Modelo de Xenoenxerto
2.
NMR Biomed ; 28(3): 317-26, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25581615

RESUMO

Patients suffering from glioblastoma multiforme (GBM) face a poor prognosis with median survival of about 14 months. High recurrence rate and failure of conventional treatments are attributed to the presence of GBM cells with stem-like properties (GSCs). Metabolite profiles of 42 GSC lines established from the tumor tissue of adult GBM patients were screened with (1) H NMR spectroscopy and compared with human neural progenitor cells from human adult olfactory bulb (OB-NPCs) and from the developing human brain (HNPCs). A first subset (n=12) of GSCs exhibited a dramatic accumulation of the metabolite α-aminoadipate (αAAD), product of the oxidation of α-aminoadipic semialdehyde catalyzed by the ALDH7A1 aldehyde dehydrogenase (ALDH) family in lysine catabolism. αAAD was low/not detectable in a second GSC subset (n=13) with the same neural metabolic profile as well as in a third GSC subset (n=17) characterized by intense lipid signals. Likewise, αAAD was not detected in the spectra of OB-NPCs or HNPCs. Inhibition of mitochondrial ATP synthase by oligomycin treatment revealed that the lysine degradative pathway leading to αAAD formation proceeds through saccharopine, as usually observed in developing brain. Survival curves indicated that high αAAD levels in GSCs significantly correlated with poor patient survival, similarly to prostate and non-small-cell-lung cancers, where activity of ALDH7A1 correlates with tumor aggressiveness.


Assuntos
Ácido 2-Aminoadípico/metabolismo , Biomarcadores Tumorais/metabolismo , Neoplasias Encefálicas/metabolismo , Glioblastoma/metabolismo , Glioblastoma/patologia , Células-Tronco Neoplásicas/metabolismo , Espectroscopia de Prótons por Ressonância Magnética , Adulto , Idoso , Neoplasias Encefálicas/patologia , Sobrevivência Celular , Feminino , Humanos , Estimativa de Kaplan-Meier , Lisina/análogos & derivados , Lisina/metabolismo , Masculino , Redes e Vias Metabólicas , Mitocôndrias/metabolismo , Análise Multivariada , Invasividade Neoplásica , Células-Tronco Neoplásicas/patologia , Processamento de Sinais Assistido por Computador
3.
Sci Rep ; 11(1): 4312, 2021 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-33619313

RESUMO

The beneficial effects of Cyclooxygenases (COX) inhibitors on human health have been known for thousands of years. Nevertheless, COXs, particularly COX-1, have been linked to a plethora of human diseases such as cancer, heart failure, neurological and neurodegenerative diseases only recently. COXs catalyze the first step in the biosynthesis of prostaglandins (PGs) and are among the most important mediators of inflammation. All published structural work on COX-1 deals with the ovine isoenzyme, which is easier to produce in milligram-quantities than the human enzyme and crystallizes readily. Here, we report the long-sought structure of the human cyclooxygenase-1 (hCOX-1) that we refined to an R/Rfree of 20.82/26.37, at 3.36 Å resolution. hCOX-1 structure provides a detailed picture of the enzyme active site and the residues crucial for inhibitor/substrate binding and catalytic activity. We compared hCOX-1 crystal structure with the ovine COX-1 and human COX-2 structures by using metrics based on Cartesian coordinates, backbone dihedral angles, and solvent accessibility coupled with multivariate methods. Differences and similarities among structures are discussed, with emphasis on the motifs responsible for the diversification of the various enzymes (primary structure, stability, catalytic activity, and specificity). The structure of hCOX-1 represents an essential step towards the development of new and more selective COX-1 inhibitors of enhanced therapeutic potential.


Assuntos
Ciclo-Oxigenase 1/química , Modelos Moleculares , Conformação Proteica , Sequência de Aminoácidos , Animais , Sítios de Ligação , Catálise , Ciclo-Oxigenase 1/metabolismo , Inibidores de Ciclo-Oxigenase/química , Inibidores de Ciclo-Oxigenase/farmacologia , Estabilidade Enzimática , Glicosilação , Humanos , Estrutura Molecular , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Proteínas Recombinantes , Ovinos , Solventes , Relação Estrutura-Atividade , Especificidade por Substrato
4.
Int J Gynecol Cancer ; 20(2): 203-11, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20169663

RESUMO

INTRODUCTION: Ovarian cancer is highly sensitive to chemotherapy but also shows a high rate of recurrence and drug resistance. These negative outcomes mostly depend on altered apoptotic pathways, making the design of new therapeutic strategies based on the induction of other types of cell death highly desirable. Several lines of research are now addressing cancer-specific features to specifically target tumor cells, thus reducing adverse effects. In this light, a great deal of attention has been devoted to the metabolic reprogramming occurring in cancer cells, which display increased levels of glycolysis compared with their normal counterparts. We recently showed that inhibition of p38alpha impairs key metabolic functions of colorectal cancer cells, inducing growth arrest, autophagy, and cell death both in vivo and in vitro. These effects are mediated by a switch from hypoxia-inducible factor 1alpha (HIF1alpha) to forkhead transcription factor O (FoxO)-dependent transcription. METHODS: We first characterized p38 expression in OVCAR-3, A2780, and SKOV-3 ovarian cancer cell lines. Then, we treated these cells with the p38alpha/p38beta-specific inhibitor SB202190 and performed a morphological, proliferation, and survival analyses. Finally, we studied HIF1alpha and FoxO3A expressions and signaling pathways to evaluate their role in SB202190-induced effects. RESULTS: p38alpha blockade induces the formation of intracellular autophagic vacuoles and reduces growth and viability of ovarian cancer cells. As in colorectal cancer, the underlying molecular mechanism seems to rely on a shift from HIF1alpha- to FoxO3A-dependent transcription, which is promoted by the activation of the adenosine monophosphate-activated protein kinase pathway. CONCLUSIONS: These data corroborate the hypothesis that pharmacological modulation of genes involved in cancer-specific homeostasis, such as p38alpha, might be exploited to design new therapeutic approaches to cancer treatment.


Assuntos
Carcinoma/metabolismo , Fatores de Transcrição Forkhead/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Proteína Quinase 14 Ativada por Mitógeno/metabolismo , Neoplasias Ovarianas/metabolismo , Proteínas Quinases Ativadas por AMP/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Sobrevivência Celular , Feminino , Proteína Forkhead Box O3 , Regulação Neoplásica da Expressão Gênica , Homeostase , Humanos , Transdução de Sinais
5.
Oncotarget ; 7(28): 44113-44128, 2016 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-27286453

RESUMO

Colorectal cancer (CRC) is one of the most common and lethal cancers worldwide. Despite recent progress, the prognosis of advanced stage CRC remains poor, mainly because of cancer recurrence and metastasis. The high morbidity and mortality of CRC has been recently ascribed to a small population of tumor cells that hold the potential of tumor initiation, i.e. cancer stem cells (CSCs), which play a pivotal role in cancer recurrence and metastasis and are not eradicated by current therapy. We screened CRC-SCs in vitro with a library of protein kinase inhibitors and showed that CRC-SCs are resistant to specific inhibition of the major signaling pathways involved in cell survival and proliferation. Nonetheless, broad-spectrum inhibition by the staurosporin derivative UCN-01 blocks CRC-SC growth and potentiates the activity of irinotecan in vitro and in vivo CRC-SC-derived models. Reverse-Phase Protein Microarrays (RPPA) revealed that, albeit CRC-SCs display individual phospho-proteomic profiles, sensitivity of CRC-SCs to UCN-01 relies on the interference with the DNA damage response mediated by Chk1. Combination of LY2603618, a specific Chk1/2 inhibitor, with irinotecan resulted in a significant reduction of CRC-SC growth in vivo, confirming that irinotecan treatment coupled to inhibition of Chk1 represents a potentially effective therapeutic approach for CRC treatment.


Assuntos
Camptotecina/análogos & derivados , Neoplasias Colorretais/tratamento farmacológico , Dano ao DNA , Células-Tronco Neoplásicas/efeitos dos fármacos , Estaurosporina/análogos & derivados , Animais , Antineoplásicos Fitogênicos/administração & dosagem , Antineoplásicos Fitogênicos/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Camptotecina/administração & dosagem , Camptotecina/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/genética , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Sinergismo Farmacológico , Células HCT116 , Humanos , Irinotecano , Camundongos , Células-Tronco Neoplásicas/metabolismo , Inibidores de Proteínas Quinases/administração & dosagem , Inibidores de Proteínas Quinases/farmacologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Estaurosporina/administração & dosagem , Estaurosporina/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto/métodos
6.
Cancer Lett ; 324(1): 98-108, 2012 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-22579651

RESUMO

We recently demonstrated that p38α is required to maintain colorectal cancer (CRC) metabolism, as its inhibition leads to FoxO3A activation, autophagy, cell death, and tumor growth reduction both in vitro and in vivo. Here we show that inhibition of p38α is followed by TRAIL-mediated activation of caspase-8 and FoxO3A-dependent HER3 upregulation with consequent overactivation of the MEK-ERK1/2 survival pathway. p38α and MEK combined inhibition specifically induces apoptosis by enabling TRAIL signaling propagation through t-Bid and caspase-3, and fosters cell death in CRC cells and preclinical mouse models. Current MEK1-directed pharmacological strategies could thus be exploited, in combination with p38α inhibition, to develop new approaches for CRC treatment.


Assuntos
Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/patologia , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Idoso , Idoso de 80 Anos ou mais , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Benzamidas/farmacologia , Caspase 8/metabolismo , Morte Celular/efeitos dos fármacos , Morte Celular/genética , Linhagem Celular Tumoral , Neoplasias Colorretais/tratamento farmacológico , Difenilamina/análogos & derivados , Difenilamina/farmacologia , Inibidores Enzimáticos/farmacologia , Feminino , Células HT29 , Humanos , Imidazóis/farmacologia , MAP Quinase Quinase 1/antagonistas & inibidores , MAP Quinase Quinase 1/genética , MAP Quinase Quinase 1/metabolismo , Masculino , Camundongos , Camundongos Nus , Pessoa de Meia-Idade , Proteína Quinase 14 Ativada por Mitógeno/antagonistas & inibidores , Proteína Quinase 14 Ativada por Mitógeno/metabolismo , Fosforilação , Piridinas/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto , Proteínas Quinases p38 Ativadas por Mitógeno/antagonistas & inibidores
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