Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Cancer Res ; 80(19): 4129-4144, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32816860

RESUMO

Therapeutic checkpoint antibodies blocking programmed death receptor 1/programmed death ligand 1 (PD-L1) signaling have radically improved clinical outcomes in cancer. However, the regulation of PD-L1 expression on tumor cells is still poorly understood. Here we show that intratumoral copper levels influence PD-L1 expression in cancer cells. Deep analysis of the The Cancer Genome Atlas database and tissue microarrays showed strong correlation between the major copper influx transporter copper transporter 1 (CTR-1) and PD-L1 expression across many cancers but not in corresponding normal tissues. Copper supplementation enhanced PD-L1 expression at mRNA and protein levels in cancer cells and RNA sequencing revealed that copper regulates key signaling pathways mediating PD-L1-driven cancer immune evasion. Conversely, copper chelators inhibited phosphorylation of STAT3 and EGFR and promoted ubiquitin-mediated degradation of PD-L1. Copper-chelating drugs also significantly increased the number of tumor-infiltrating CD8+ T and natural killer cells, slowed tumor growth, and improved mouse survival. Overall, this study reveals an important role for copper in regulating PD-L1 and suggests that anticancer immunotherapy might be enhanced by pharmacologically reducing intratumor copper levels. SIGNIFICANCE: These findings characterize the role of copper in modulating PD-L1 expression and contributing to cancer immune evasion, highlighting the potential for repurposing copper chelators as enhancers of antitumor immunity. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/19/4129/F1.large.jpg.


Assuntos
Antígeno B7-H1/metabolismo , Neoplasias Encefálicas/imunologia , Cobre/metabolismo , Neuroblastoma/imunologia , Evasão Tumoral/fisiologia , Animais , Antígeno B7-H1/genética , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/metabolismo , Linhagem Celular Tumoral , Quelantes/farmacologia , Transportador de Cobre 1/metabolismo , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/imunologia , Humanos , Imunoterapia/métodos , Células Matadoras Naturais , Linfócitos do Interstício Tumoral/patologia , Camundongos Endogâmicos BALB C , Neuroblastoma/tratamento farmacológico , Neuroblastoma/metabolismo , Trietilenofosforamida/farmacologia , Evasão Tumoral/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
2.
ACS Pharmacol Transl Sci ; 3(1): 148-160, 2020 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-32259094

RESUMO

MYCN-amplified neuroblastoma is one of the deadliest forms of childhood cancer and remains a significant clinical challenge. Direct pharmacological inhibition of MYCN is not currently achievable. One strategy could be to target the AKT/GSK3ß pathway, which directly regulates the stability of the MYCN protein. Numerous potent and isoform-specific small-molecule AKT inhibitors have been developed. However, the selection of the right drug combinations in the relevant indication will have a significant impact on AKT inhibitor clinical success. To maximally exploit the potential of AKT inhibitors, a better understanding of AKT isoform functions in cancer is crucial. Here using RNAi to downregulate specific AKT isoforms, we demonstrated that loss of total AKT activity rather than isoform-specific expression was necessary to decrease MYCN expression and cause a significant decrease in neuroblastoma cell proliferation. Consistent with these observations, isoform-specific pharmacological inhibition of AKT was substantially less effective than pan-AKT inhibition in combination with cytotoxic drugs in MYCN-amplified neuroblastoma. The allosteric pan-AKT inhibitor perifosine had promising in vitro and in vivo activity in combination with conventional cytotoxic drugs in MYCN-amplified neuroblastoma cells. Our results demonstrated that perifosine drug combination was able to induce apoptosis and downregulate ABC transporter expression. Collectively, this study shows that selecting pan-AKT inhibitors rather than isoform-specific drugs to synergize with first-line chemotherapy treatment should be considered for clinical trials for aggressive neuroblastoma and, potentially, other MYCN -driven cancers.

3.
Theranostics ; 8(20): 5645-5659, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30555570

RESUMO

Given the strong clinical evidence that copper levels are significantly elevated in a wide spectrum of tumors, copper homeostasis is considered as an emerging target for anticancer drug design. Monitoring copper levels in vivo is therefore of paramount importance when assessing the efficacy of copper-targeting drugs. Herein, we investigated the activity of the copper-targeting compound Dextran-Catechin by developing a [64Cu]CuCl2 PET imaging protocol to monitor its effect on copper homeostasis in tumors. Methods: Protein expression of copper transporter 1 (CTR1) in tissue microarrays representing 90 neuroblastoma patient tumors was assessed by immunohistochemistry. Western blotting analysis was used to study the effect of Dextran-Catechin on the expression of CTR1 in neuroblastoma cell lines and in tumors. A preclinical human neuroblastoma xenograft model was used to study anticancer activity of Dextran-Catechin in vivo and its effect on tumor copper homeostasis. PET imaging with [64Cu]CuCl2 was performed in such preclinical neuroblastoma model to monitor alteration of copper levels in tumors during treatment. Results: CTR1 protein was found to be highly expressed in patient neuroblastoma tumors by immunohistochemistry. Treatment of neuroblastoma cell lines with Dextran-Catechin resulted in decreased levels of glutathione and in downregulation of CTR1 expression, which caused a significant decrease of intracellular copper. No changes in CTR1 expression was observed in normal human astrocytes after Dextran-Catechin treatment. In vivo studies and PET imaging analysis using the neuroblastoma preclinical model revealed elevated [64Cu]CuCl2 retention in the tumor mass. Following treatment with Dextran-Catechin, there was a significant reduction in radioactive uptake, as well as reduced tumor growth. Ex vivo analysis of tumors collected from Dextran-Catechin treated mice confirmed the reduced levels of CTR1. Interestingly, copper levels in blood were not affected by treatment, demonstrating potential tumor specificity of Dextran-Catechin activity. Conclusion: Dextran-Catechin mediates its activity by lowering CTR1 and intracellular copper levels in tumors. This finding further reveals a potential therapeutic strategy for targeting copper-dependent cancers and presents a novel PET imaging method to assess patient response to copper-targeting anticancer treatments.


Assuntos
Tomografia por Emissão de Pósitrons/métodos , Animais , Catequina , Proteínas de Transporte de Cátions , Linhagem Celular Tumoral , Cobre , Transportador de Cobre 1 , Dextranos , Feminino , Homeostase , Humanos , Imuno-Histoquímica , Técnicas In Vitro , Camundongos , Camundongos Endogâmicos BALB C , Imagem Molecular , Neuroblastoma , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Análise Serial de Tecidos
4.
Nat Commun ; 9(1): 2288, 2018 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-29895867

RESUMO

For many normal and aberrant cell behaviours, it is important to understand the origin of cellular heterogeneity. Although powerful methods for studying cell heterogeneity have emerged, they are more suitable for common rather than rare cells. Exploring the heterogeneity of rare single cells is challenging because these rare cells must be first pre-concentrated and undergo analysis prior to classification and expansion. Here, a versatile capture & release platform consisting of an antibody-modified and electrochemically cleavable semiconducting silicon surface for release of individual cells of interest is presented. The captured cells can be interrogated microscopically and tested for drug responsiveness prior to release and recovery. The capture & release strategy was applied to identify rare tumour cells from whole blood, monitor the uptake of, and response to, doxorubicin and subsequently select cells for single-cell gene expression based on their response to the doxorubicin.


Assuntos
Técnicas Eletroquímicas , Fotoquímica/métodos , Análise de Célula Única , Animais , Sobrevivência Celular , Doxorrubicina/química , Feminino , Células HeLa , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Células MCF-7 , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Microscopia de Fluorescência , Transplante de Neoplasias , Silício/química
5.
Sci Rep ; 7(1): 7638, 2017 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-28794411

RESUMO

Formation of blood vessels, or angiogenesis, is crucial to cancer progression. Thus, inhibiting angiogenesis can limit the growth and spread of tumors. The natural polyphenol catechin has moderate anti-tumor activity and interacts with copper, which is essential for angiogenesis. Catechin is easily metabolized in the body and this limits its clinical application. We have recently shown that conjugation of catechin with dextran (Dextran-Catechin) improves its serum stability, and exhibits potent anti-tumor activity against neuroblastoma by targeting copper homeostasis. Herein, we investigated the antiangiogenic activity of Dextran-Catechin and its mechanism. We found that Dextran-Catechin displayed potent antiangiogenic activity in vitro and in vivo. We demonstrated Dextran-Catechin generates reactive oxygen species which in turns disrupts copper homeostasis by depleting the copper importer CTR-1 and copper trafficking ATOX-1 protein. Mechanistically, we showed that disrupting copper homeostasis by knockdown of either CTR-1 or ATOX-1 protein can inhibit angiogenesis in endothelial cells. This data strongly suggests the Dextran-Catechin potent antiangiogenic activity is mediated by disrupting copper homeostasis. Thus, compounds such as Dextran-Catechin that affects both tumor growth and angiogenesis could lead the way for development of new drugs against high copper levels tumors.


Assuntos
Antineoplásicos/metabolismo , Catequina/metabolismo , Cobre/metabolismo , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Homeostase/efeitos dos fármacos , Neovascularização Patológica , Animais , Antineoplásicos/administração & dosagem , Catequina/administração & dosagem , Proteínas de Transporte de Cátions/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Proteínas de Transporte de Cobre , Transportador de Cobre 1 , Dextranos/administração & dosagem , Dextranos/metabolismo , Modelos Animais de Doenças , Xenoenxertos , Humanos , Metalochaperonas/metabolismo , Chaperonas Moleculares , Transplante de Neoplasias , Neuroblastoma/tratamento farmacológico , Neuroblastoma/patologia , Espécies Reativas de Oxigênio/metabolismo , Oligoelementos/metabolismo , Resultado do Tratamento
6.
Oncotarget ; 7(30): 47479-47493, 2016 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-27374085

RESUMO

Neuroblastoma is frequently diagnosed at advanced stage disease and treatment includes high dose chemotherapy and surgery. Despite the use of aggressive therapy survival rates are poor and children that survive their disease experience long term side effects from their treatment, highlighting the need for effective and less toxic therapies. Catechin is a natural polyphenol with anti-cancer properties and limited side effects, however its mechanism of action is unknown. Here we report that Dextran-Catechin, a conjugated form of catechin that increases serum stability, is preferentially and markedly active against neuroblastoma cells having high levels of intracellular copper, without affecting non-malignant cells. Copper transporter 1 (CTR1) is the main transporter of copper in mammalian cells and it is upregulated in neuroblastoma. Functional studies showed that depletion of CTR1 expression reduced intracellular copper levels and led to a decrease in neuroblastoma cell sensitivity to Dextran-Catechin, implicating copper in the activity of this compound. Mechanistically, Dextran-Catechin was found to react with copper, inducing oxidative stress and decreasing glutathione levels, an intracellular antioxidant and regulator of copper homeostasis. In vivo, Dextran-Catechin significantly attenuated tumour growth in human xenograft and syngeneic models of neuroblastoma. Thus, Dextran-Catechin targets copper, inhibits tumour growth, and may be valuable in the treatment of aggressive neuroblastoma and other cancers dependent on copper for their growth.


Assuntos
Antineoplásicos/farmacologia , Catequina/farmacologia , Cobre/metabolismo , Dextranos/farmacologia , Neuroblastoma/tratamento farmacológico , Animais , Proteínas de Transporte de Cátions/fisiologia , Sobrevivência Celular/efeitos dos fármacos , Transportador de Cobre 1 , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Neuroblastoma/metabolismo , Neuroblastoma/patologia , Estresse Oxidativo/efeitos dos fármacos
7.
Oncotarget ; 6(14): 12020-34, 2015 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-25557168

RESUMO

Non-small cell lung cancer (NSCLC) remains the most common cause of cancer death worldwide due its resistance to chemotherapy and aggressive tumor growth. Polo-like kinase 1 (PLK1) is a serine-threonine protein kinase which is overexpressed in cancer cells, and plays a major role in regulating tumor growth. A number of PLK1 inhibitors are in clinical trial; however, poor tumor bioavailability and off-target effects limit their efficacy. Short-interfering-RNA (siRNA) holds promise as a class of therapeutics, which can selectively silence disease-causing genes. However, siRNA cannot enter cells without a delivery vehicle. Herein, we investigated whether RNAi-interfering nanoparticles could deliver siRNA to NSCLC cells and silence PLK1 expression in vitro and in vivo. iNOP-7 was non-toxic, and delivered siRNA with high efficiency to NSCLC cells. iNOP-7-PLK1 siRNA silenced PLK1 expression and reduced NSCLC growth in vitro. Notably, iNOP-7 delivered siRNA to orthotopic lung tumors in mice, and administration of iNOP-7-PLK1 siRNA reduced lung tumor burden. These novel data show that iNOP-7 can deliver siRNA against PLK1 to NSCLC cells, and decrease cell proliferation both in vitro and in vivo. iNOP-7-PLK1 siRNA may provide a novel therapeutic strategy for the treatment of NSCLC as well as other cancers which aberrantly express this gene.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/terapia , Proteínas de Ciclo Celular/genética , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/terapia , Proteínas Serina-Treonina Quinases/genética , Proteínas Proto-Oncogênicas/genética , Interferência de RNA/imunologia , RNA Interferente Pequeno/genética , Animais , Proliferação de Células , Humanos , Camundongos , Nanopartículas , Transfecção
8.
Nanoscale ; 3(3): 919-24, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21173998

RESUMO

We demonstrate that oral delivery of self-assembled nanostructured nanoparticles consisting of 5-fluorouracil (5-FU) lipid prodrugs results in a highly effective, target-activated, chemotherapeutic agent, and offers significantly enhanced efficacy over a commercially available alternative that does not self-assemble. The lipid prodrug nanoparticles have been found to significantly slow the growth of a highly aggressive mouse 4T1 breast tumour, and essentially halt the growth of a human MDA-MB-231 breast tumour in mouse xenografts. Systemic toxicity is avoided as prodrug activation requires a three-step, enzymatic conversion to 5-FU, with the third step occurring preferentially at the tumour site. Additionally, differences in the lipid prodrug chemical structure and internal nanostructure of the nanoparticle dictate the enzymatic conversion rate and can be used to control sustained release profiles. Thus, we have developed novel oral nanomedicines that combine sustained release properties with target-selective activation.


Assuntos
Neoplasias da Mama/tratamento farmacológico , Fluoruracila/administração & dosagem , Lipídeos/química , Nanocápsulas/administração & dosagem , Administração Oral , Animais , Antimetabólitos Antineoplásicos/administração & dosagem , Antimetabólitos Antineoplásicos/química , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Cristalização/métodos , Composição de Medicamentos/métodos , Fluoruracila/química , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Nanocápsulas/química , Nanomedicina/métodos , Pró-Fármacos , Resultado do Tratamento
9.
Physiol Biochem Zool ; 82(3): 270-9, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19331583

RESUMO

Phenotypic plasticity of the gastrointestinal tract is crucial for optimal food processing and nutrient balance in many vertebrate species. For mammalian herbivores, gut plasticity is typically correlated with the fiber content of forage; however, we show here that other factors such as ingesta particle size may effect profound phenotypic plasticity of the fermentative hindgut in a medium-sized (10-kg body mass) marsupial herbivore, the red-necked wallaby (Macropus rufogriseus). When dietary fiber contents were comparable, red-necked wallabies that were fed a finely ground, pelleted hay for 60-72 d had hindguts that were some 28% heavier (empty wet mass) than those fed unchopped hay. The hindguts of pellet-fed wallabies contained more wet ingesta, which was also of a finer particle size, than those fed hay, indicating some separation of large- and small-particle fermentation between the foregut and the hindgut, respectively. Such a digestive strategy would benefit animals by allowing fermentation of a range of ingesta particle sizes that are expected for free-ranging animals faced with a spectrum of diet types and qualities. The heavier hindgut of pellet-fed wallabies was correlated with increased concentrations of short-chain fatty acids (SCFAs) in the fermentative hindgut (cecum and proximal colon) and particularly with increases in the molar proportions of n-butyric acid. The mechanisms facilitating gut plasticity in herbivorous mammals are uncertain, but we suggest that manipulating ingesta particle size rather than dietary fiber could provide a useful tool for evaluating causal explanations. In particular, altering ingesta particle size could help to distinguish possible direct processes (e.g., the favoring of smaller intestinal microbes and production of specific SCFAs) from indirect affects of feed structure (e.g., muscular hypertrophy to compensate for increased intakes and digesta bulk or the fermentation of mucus secreted to promote the flow of viscous, fine-particle material).


Assuntos
Adaptação Fisiológica , Ração Animal , Fibras na Dieta , Trato Gastrointestinal/fisiologia , Macropodidae/fisiologia , Animais , Metabolismo Energético , Feminino , Trato Gastrointestinal/anatomia & histologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...