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1.
Int J Mol Sci ; 23(19)2022 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-36232407

RESUMO

Ferroptosis is a type of iron-dependent cell death pertaining to an excess of lipid peroxidation. It has been suggested that sorafenib-an anti-angiogenic medication for hepatocellular carcinoma (HCC)-induces ferroptosis, but the underlying mechanism for this remains largely unknown. We employed siRNA-mediated gene silencing to investigate the role of Src homology region 2 domain-containing phosphatase-1 (SHP-1), following sorafenib treatment, in cystine/glutamate-antiporter-system-Xc--regulated cystine uptake. Co-immunoprecipitation was also performed to examine the interactions between MCL1, beclin 1 (BECN1), and solute carrier family 7 member 11 (SLC7A11), which functions as the catalytic subunit of system Xc-. The results of this study showed that sorafenib enhanced the activity of SHP-1, dephosphorylated STAT3, downregulated the expression of MCL1 and, consequently, reduced the association between MCL1 and BECN1. In contrast, increased binding between BECN1 and SLC7A11 was observed following sorafenib treatment. The elevated interaction between BECN1 and SLC7A11 inhibited the activity of system Xc-, whereas BECN1 silencing restored cystine intake and protected cells from ferroptosis. Notably, ectopic expression of MCL1 uncoupled BECN1 from SLC7A11 and rescued cell viability by attenuating lipid peroxidation. The results revealed that ferroptosis could be induced in HCC via SHP-1/STAT3-mediated downregulation of MCL1 and subsequent inhibition of SLC7A11 by increased BECN1 binding.


Assuntos
Carcinoma Hepatocelular , Ferroptose , Neoplasias Hepáticas , Sistema y+ de Transporte de Aminoácidos/genética , Sistema y+ de Transporte de Aminoácidos/metabolismo , Antiporters , Apoptose , Proteína Beclina-1/metabolismo , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Linhagem Celular Tumoral , Cistina/metabolismo , Glutamatos/uso terapêutico , Humanos , Ferro/metabolismo , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Proteína Tirosina Fosfatase não Receptora Tipo 6/genética , Proteína Tirosina Fosfatase não Receptora Tipo 6/metabolismo , RNA Interferente Pequeno/uso terapêutico , Fator de Transcrição STAT3 , Sorafenibe/farmacologia , Sorafenibe/uso terapêutico
2.
J Pharmacol Exp Ther ; 366(3): 410-421, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29914877

RESUMO

Increasing evidence suggests that SET functions as an oncoprotein and promotes cancer survival and therapeutic resistance. However, whether SET affects radiation therapy (RT)-mediated anticancer effects has not yet been explored. We investigated the impact of SET on RT sensitivity in hepatocellular carcinoma (HCC). Using colony and hepatosphere formation assays, we found that RT-induced proliferative inhibition was critically associated with SET expression. We next tested a novel SET antagonist, N4-(3-ethynylphenyl)-6,7-dimethoxy-N2-(4-phenoxyphenyl) quinazoline-2,4-diamine (EMQA), in combination with RT. We showed that additive use of EMQA significantly enhanced the effects of RT against HCC in vitro and in vivo. Notably, compared with mice receiving either RT or EMQA alone, the growth of PLC5 xenografted tumor in mice receiving RT plus EMQA was significantly reduced without compromising treatment tolerability. Furthermore, we proved that antagonizing SET to restore protein phosphatase 2A-mediated phospho-Akt (p-AKT) downregulation was responsible for the synergism between EMQA and RT. Our data demonstrate a new oncogenic property of SET and provide preclinical evidence that combining a SET antagonist and RT may be effective for treatment of HCC. Further investigation is warranted to validate the clinical relevance of this approach.


Assuntos
Carcinoma Hepatocelular/radioterapia , Regulação para Baixo/efeitos dos fármacos , Chaperonas de Histonas/antagonistas & inibidores , Neoplasias Hepáticas/radioterapia , Proteína Fosfatase 2/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Quinazolinas/farmacologia , Fatores de Transcrição/antagonistas & inibidores , Animais , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Proteínas de Ligação a DNA , Regulação para Baixo/efeitos da radiação , Ativação Enzimática/efeitos dos fármacos , Ativação Enzimática/efeitos da radiação , Humanos , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Masculino , Camundongos , Ensaios Antitumorais Modelo de Xenoenxerto
3.
Liver Int ; 38(12): 2248-2259, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-29797403

RESUMO

BACKGROUND & AIMS: Few molecules are currently verified to be actionable drug targets in cholangiocarcinoma (CCA). Serine/threonine protein phosphatase 5 (PP5) dysregulation is related to several malignancies. However, the role of PP5 in CCA is poorly defined. METHODS: Colony and tumorsphere formation assays were conducted to establish the role of PP5 in CCA tumorigenesis. Cantharidin (CTD) and norcantharidin (NCTD), both potent PP5 inhibitors, were used in in vitro and in vivo experiments to validate the potential therapeutic role of PP5. RESULTS: Increased cell growth, colony formation and tumorsphere formation were observed in PP5-overexpressing CCA cells, whereas PP5 knockdown by shRNA decreased cell growth and colony formation. Tumours from HuCCT1 xenograft-bearing mice treated with PP5-shRNA showed decreased growth and increased AMP-activated protein kinase (AMPK) phosphorylation. Furthermore, CTD treatment decreased cell viability, reduced PP5 activity and enhanced AMPK phosphorylation in CCA cell lines. Overexpressing PP5 or enhancing PP5 activity suppressed AMPK phosphorylation and decreased CTD-induced cell death. Suppressing p-AMPK with siRNA or inhibitors also decreased CTD-induced cell death, suggesting a pivotal role for PP5-AMPK cascades in CCA. Immunoprecipitation revealed that PP5 interacted with AMPK. Importantly, treatment of HuCCT1 xenograft-bearing mice with NCTD, a CTD analogue with a lower systemic toxicity in vivo, suppressed PP5 activity, increased p-AMPK and reduced tumour volume. CONCLUSIONS: Protein phosphatase 5 negatively regulates AMPK phosphorylation and contributes to CCA aggressiveness; thus, PP5 may be a potential therapeutic target in CCA.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Neoplasias dos Ductos Biliares/metabolismo , Colangiocarcinoma/metabolismo , Proteínas Nucleares/antagonistas & inibidores , Fosfoproteínas Fosfatases/antagonistas & inibidores , Animais , Antineoplásicos/farmacologia , Apoptose , Neoplasias dos Ductos Biliares/tratamento farmacológico , Neoplasias dos Ductos Biliares/patologia , Cantaridina/farmacologia , Carcinogênese , Linhagem Celular Tumoral , Proliferação de Células , Sobrevivência Celular , Colangiocarcinoma/tratamento farmacológico , Colangiocarcinoma/patologia , Inibidores Enzimáticos/farmacologia , Humanos , Masculino , Camundongos , Camundongos Knockout , Camundongos Nus , Proteínas Nucleares/genética , Fosfoproteínas Fosfatases/genética , Ensaios Antitumorais Modelo de Xenoenxerto
4.
Gastroenterology ; 149(2): 468-80.e10, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25888330

RESUMO

BACKGROUND & AIMS: Reactive oxidative species (ROS) are believed to be involved in the progression of nonalcoholic steatohepatitis (NASH). However, little is known about the sources of ROS in hepatocytes or their role in disease progression. We studied the effects of nicotinamide adenine dinucleotide phosphate reduced oxidase 4 (NOX4) in liver tissues from patients with NASH and mice with steatohepatitis. METHODS: Liver biopsy samples were obtained from 5 patients with NASH, as well as 4 patients with simple steatosis and 5 patients without steatosis (controls) from the University of California, Davis Cancer Center Biorepository. Mice with hepatocyte-specific deletion of NOX4 (NOX4(hepKO)) and NOX4(floxp+/+) C57BL/6 mice (controls) were given fast-food diets (supplemented with high-fructose corn syrup) or choline-deficient l-amino acid defined diets to induce steatohepatitis, or control diets, for 20 weeks. A separate group of mice were given the NOX4 inhibitor (GKT137831). Liver tissues were collected and immunoblot analyses were performed determine levels of NOX4, markers of inflammation and fibrosis, double-stranded RNA-activated protein kinase, and phospho-eIF-2α kinase-mediated stress signaling pathways. We performed hyperinsulinemic-euglycemic clamp studies and immunoprecipitation analyses to determine the oxidation and phosphatase activity of PP1C. RESULTS: Levels of NOX4 were increased in patients with NASH compared with controls. Hepatocyte-specific deletion of NOX4 reduced oxidative stress, lipid peroxidation, and liver fibrosis in mice with diet-induced steatohepatitis. A small molecule inhibitor of NOX4 reduced liver inflammation and fibrosis and increased insulin sensitivity in mice with diet-induced steatohepatitis. In primary hepatocytes, NOX4 reduced the activity of the phosphatase PP1C, prolonging activation of double-stranded RNA-activated protein kinase and phosphorylation of extracellular signal-regulated kinase-mediated stress signaling. Mice with hepatocyte-specific deletion of NOX4 and mice given GKT137831 had increased insulin sensitivity. CONCLUSIONS: NOX4 regulates oxidative stress in the liver and its levels are increased in patients with NASH and mice with diet-induced steatohepatitis. Inhibitors of NOX4 reduce liver inflammation and fibrosis and increase insulin sensitivity, and might be developed for treatment of NASH.


Assuntos
Fígado Gorduroso/tratamento farmacológico , Hepatócitos/efeitos dos fármacos , Resistência à Insulina , Cirrose Hepática/tratamento farmacológico , NADPH Oxidases/metabolismo , NADP/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Animais , Biomarcadores/metabolismo , Biópsia , Dieta/métodos , Modelos Animais de Doenças , Fígado Gorduroso/induzido quimicamente , Fígado Gorduroso/genética , Fígado Gorduroso/metabolismo , Hepatócitos/metabolismo , Humanos , Peroxidação de Lipídeos/efeitos dos fármacos , Fígado/citologia , Fígado/patologia , Cirrose Hepática/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , NADP/administração & dosagem , NADPH Oxidase 4 , Obesidade/tratamento farmacológico , Obesidade/metabolismo , Proteína Fosfatase 1/metabolismo , Pirazóis/metabolismo , Pirazolonas , Piridinas/metabolismo , Piridonas , Estresse Fisiológico/efeitos dos fármacos
5.
Cancer Lett ; 498: 142-151, 2021 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-33232786

RESUMO

Recent advances in immune checkpoint inhibition, which augment T-cell immune responses, have highlighted the potential of exploiting one's immune system to combat cancer. However, only a relatively small number of non-small cell lung cancer (NSCLC) patients benefit from immune checkpoint blockade due to the immunosuppressive tumor microenvironment. Therefore, combination immunotherapies are now being developed to achieve maximal therapeutic benefits. In this study, we assessed whether a novel erlotinib derivative, TD-92, which possesses anti-tumor effects across several cancer cell lines, could enhance anti-PD-1 treatment. Our results demonstrated that the combined treatment of anti-PD-1 and TD-92 resulted in a potent anti-tumor response in a Lewis lung carcinoma cancer model, as evidenced by the reduced tumor growth and increased survival. Analysis of immune cell population counts revealed that TD-92 reduced the number of pro-tumorigenic CD11b+ F4/80+ tumor-associated macrophages, without significantly affecting the total numbers of other major immunocytes. Further experiments showed that TD-92 induced a marked decline in colony stimulating factor 1 receptor (CSF-1R) expression in macrophage cell lines. The results also suggested that c-Cbl-mediated proteasome degradation was involved in TD-92-mediated CSF-1R downregulation. Our data paves the way for the development of additional combination immunotherapies for NSCLC patients.


Assuntos
Antineoplásicos/farmacologia , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Regulação para Baixo/efeitos dos fármacos , Cloridrato de Erlotinib/farmacologia , Neoplasias Pulmonares/tratamento farmacológico , Receptor de Morte Celular Programada 1/metabolismo , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/metabolismo , Macrófagos Associados a Tumor/efeitos dos fármacos , Animais , Biomarcadores Tumorais/metabolismo , Carcinoma Pulmonar de Lewis/tratamento farmacológico , Carcinoma Pulmonar de Lewis/metabolismo , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Linhagem Celular Tumoral , Humanos , Imunoterapia/métodos , Neoplasias Pulmonares/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Microambiente Tumoral/efeitos dos fármacos , Macrófagos Associados a Tumor/metabolismo
6.
Biochem Biophys Res Commun ; 384(4): 426-30, 2009 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-19426708

RESUMO

Human embryonic stem cells (hESCs) hold great promise for regenerative medicine and transplantation therapy due to their self-renewal and pluripotent properties. We report that 2D thin film scaffolds composed of biocompatible polymer grafted carbon nanotubes (CNTs), can selectively differentiate human embryonic stem cells into neuron cells while maintaining excellent cell viability. According to fluorescence image analysis, neuron differentiation efficiency of poly(acrylic acid) grafted CNT thin films is significant greater than that on poly(acrylic acid) thin films. When compared with the conventional poly-L-ornithine surfaces, a standard substratum commonly used for neuron culture, this new type thin film scaffold shows enhanced neuron differentiation. No noticeable cytotoxic effect difference has been detected between these two surfaces. The surface analysis and cell adhesion study have suggested that CNT-based surfaces can enhance protein adsorption and cell attachment. This finding indicates that CNT-based materials are excellent candidates for hESCs' neuron differentiation.


Assuntos
Materiais Biocompatíveis/farmacologia , Células-Tronco Embrionárias/efeitos dos fármacos , Nanotubos de Carbono , Neurogênese , Neurônios/citologia , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Células-Tronco Embrionárias/fisiologia , Humanos , Polímeros/farmacologia
7.
Cell Death Dis ; 10(6): 420, 2019 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-31142735

RESUMO

Accelerated glucose metabolism is critical in hepatocarcinogenesis, but the utilities of different glucose transporter inhibitors in treating hepatocellular carcinoma (HCC) remain largely uncharacterized. In this study, we examined a collection of glucose transporter inhibitors and found differential anti-HCC effects among these compounds. Canagliflozin (CANA), phloretin, and WZB117 decreased cellular glucose influx, but only CANA showed potent growth inhibition in HCC, which indicated a glucose-independent anti-HCC mechanism. Notably, we found that CANA treatment significantly downregulated the expression of ß-catenin in HCC cells in. By co-treating cells with cycloheximide and MG-132, we proved that CANA promoted proteasomal degradation of ß-catenin protein by increasing phosphorylation of ß-catenin, and CANA-induced inactivation of protein phosphatase 2A was identified being responsible for this effect. Moreover, using Huh7 xenografted tumor model, CANA treatment was shown to delay tumor growth and improved the survival of HCC bearing mice. Our study highlights the unique dual ß-catenin-inhibition mechanisms of CANA, which may provide new thoughts on treating HCC patient with concurrent diabetes, and, furthermore, on developing novel treatment targeting metabolic reprogram and/or WNT/ß-catenin signaling in HCC.


Assuntos
Canagliflozina/farmacologia , Proliferação de Células/efeitos dos fármacos , Glucose/metabolismo , beta Catenina/metabolismo , Animais , Canagliflozina/uso terapêutico , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Cicloeximida/farmacologia , Regulação para Baixo/efeitos dos fármacos , Transportador de Glucose Tipo 1/antagonistas & inibidores , Transportador de Glucose Tipo 1/genética , Transportador de Glucose Tipo 1/metabolismo , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/patologia , Camundongos , Fosforilação/efeitos dos fármacos , Proteína Fosfatase 2/metabolismo , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Transportador 2 de Glucose-Sódio/metabolismo , Transplante Heterólogo , Via de Sinalização Wnt/efeitos dos fármacos
8.
Eur J Cancer ; 102: 10-22, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30103095

RESUMO

AIM: Palbociclib is an oral cyclin-dependent kinase 4/6 inhibitor, which is efficacious in treating breast cancer. Currently, there are numerous active clinical trials testing palbociclib alone or in combination with other medications for treating various types of malignancies. Here, we evaluated the anti-cancer effect of palbociclib in combination with radiation therapy (RT) for treating human hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) and addressed the molecular mechanism behind the combination therapy. METHODS: Immunofluorescence staining of γH2AX or 53BP1 was used to determine the effect of palbociclib on double-strand break (DSB) repair. Clonogenic assays, sphere formation and cell death ELISA were performed to study the sensitising effect of palbociclib on radiation-induced cytotoxicity. Signal alteration in DSB repair pathways was examined by Western blot analysis. Finally, we evaluated the in vivo anti-cancer activity and the associated molecular events of the combination therapy in a preclinical HCC xenograft model. RESULTS: Palbociclib affected the kinetics of DNA repair and enhanced the radiation sensitivity of HCC and CCA cells. Importantly, we found that palbociclib inhibits ataxia telangiectasia-mutated (ATM) kinase, the key upstream kinase responding to RT-induced DSBs. Furthermore, we showed that the inhibitory effect of palbociclib on RT-induced ATM kinase activation is mediated by protein phosphatase 5 (PP5). Both in vitro and in vivo investigations revealed that the inhibition of the PP5-ATM axis by palbociclib after DNA damage is responsible for the synergism between palbociclib and RT. CONCLUSION: Our findings provide a novel combination strategy against liver cancer cells. Clinical trials using palbociclib as an adjuvant in RT are warranted.


Assuntos
Antineoplásicos/farmacologia , Proteínas Mutadas de Ataxia Telangiectasia/antagonistas & inibidores , Neoplasias dos Ductos Biliares/terapia , Carcinoma Hepatocelular/terapia , Quimiorradioterapia , Colangiocarcinoma/terapia , Quebras de DNA de Cadeia Dupla , Reparo do DNA/efeitos dos fármacos , Neoplasias Hepáticas/terapia , Piperazinas/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Piridinas/farmacologia , Radiossensibilizantes/farmacologia , Animais , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Neoplasias dos Ductos Biliares/enzimologia , Neoplasias dos Ductos Biliares/genética , Neoplasias dos Ductos Biliares/patologia , Carcinoma Hepatocelular/enzimologia , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Colangiocarcinoma/enzimologia , Colangiocarcinoma/genética , Colangiocarcinoma/patologia , Histonas/metabolismo , Humanos , Cinética , Neoplasias Hepáticas/enzimologia , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Masculino , Camundongos Nus , Tolerância a Radiação , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
9.
Oncotarget ; 8(39): 65077-65089, 2017 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-29029413

RESUMO

Sorafenib is a multiple kinase inhibitor which targets Raf kinases, VEGFR, and PDGFR and is approved for the treatment of hepatocellular carcinoma (HCC). Previously, we found that p-STAT3 is a major target of SC-43, a sorafenib derivative. In this study, we report that SC-43-induced apoptosis in cholangiocarcinoma (CCA) via a novel mechanism. Three CCA cell lines (HuCCT-1, KKU-100 and CGCCA) were treated with SC-43 to determine their sensitivity to SC-43-induced cell death and apoptosis. We found that SC-43 activated SH2 domain-containing phosphatase 1 (SHP-1) activity, leading to p-STAT3 and downstream cyclin B1 and Cdc2 downregulation, which induced G2-M arrest and apoptotic cell death. Importantly, SC-43 augmented SHP-1 activity by direct binding to N-SH2 and relief of its autoinhibition. Deletion of the N-SH2 domain (dN1) or point mutation (D61A) of SHP-1 counteracted the effect of SC-43-induced SHP-1 phosphatase activation and antiproliferation ability in CCA cells. In vivo assay revealed that SC-43 exhibited xenograft tumor growth inhibition, p-STAT3 reduction and SHP-1 activity elevation. In conclusion, SC-43 induced apoptosis in CCA cells through the SHP-1/STAT3 signaling pathway.

10.
Mol Oncol ; 11(8): 1035-1049, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28453226

RESUMO

Palbociclib, a CDK4/6 inhibitor, has recently been approved for hormone receptor-positive breast cancer patients. The effects of palbociclib as a treatment for other malignancies, including hepatocellular carcinoma (HCC), are of great clinical interest and are under active investigation. Here, we report the effects and a novel mechanism of action of palbociclib in HCC. We found that palbociclib induced both autophagy and apoptosis in HCC cells through a mechanism involving 5' AMP-activated protein kinase (AMPK) activation and protein phosphatase 5 (PP5) inhibition. Blockade of AMPK signals or ectopic expression of PP5 counteracted the effect of palbociclib, confirming the involvement of the PP5/AMPK axis in palbociclib-mediated HCC cell death. However, CDK4/6 inhibition by lentivirus-mediated shRNA expression did not reproduce the effect of palbociclib-treated cells, suggesting that the anti-HCC effect of palbociclib is independent of CDK4/6. Moreover, two other CDK4/6 inhibitors (ribociclib and abemaciclib) had minimal effects on HCC cell viability and the PP5/AMPK axis. Palbociclib also demonstrated significant tumor-suppressive activity in a HCC xenograft model, which was associated with upregulation of pAMPK and PP5 inhibition. Finally, we analyzed 153 HCC clinical samples and found that PP5 expression was highly tumor specific and was associated with poor clinical features. Taken together, we conclude that palbociclib exerted antitumor activity against HCC through the PP5/AMPK axis independent of CDK4/6. Our findings provide a novel mechanistic basis for palbociclib and reveal the therapeutic potential of targeting PP5/AMPK signaling with a PP5 inhibitor for the treatment of hepatocellular carcinoma.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Carcinoma Hepatocelular/metabolismo , Quinase 4 Dependente de Ciclina/metabolismo , Quinase 6 Dependente de Ciclina/metabolismo , Neoplasias Hepáticas/metabolismo , Proteínas de Neoplasias/metabolismo , Piperazinas/farmacologia , Piridinas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Ativação Enzimática/efeitos dos fármacos , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/patologia
11.
Biochem Pharmacol ; 138: 49-60, 2017 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-28528695

RESUMO

The serine-threonine protein phosphatase family members are known as critical regulators of various cellular functions, such as survival and transformation. Growing evidence suggests that pharmacological manipulation of phosphatase activity exhibits therapeutic benefits. Ser/Thr protein phosphatase 5 (PP5) is known to participate in glucocorticoid receptor (GR) and stress-induced signaling cascades that regulate cell growth and apoptosis, and has been shown to be overexpressed in various human malignant diseases. However, the role of PP5 in hepatocellular carcinoma (HCC) and whether PP5 may be a viable therapeutic target for HCC treatment are unknown. Here, by analyzing HCC clinical samples obtained from 215 patients, we found that overexpression of PP5 is tumor specific and associated with worse clinical outcomes. We further characterized the oncogenic properties of PP5 in HCC cells. Importantly, both silencing of PP5 with lentiviral-mediated short hairpin RNA (shRNA) and chemical inhibition of PP5 phosphatase activity using the natural compound cantharidin/norcantharidin markedly suppressed the growth of HCC cells and tumors in vitro and in vivo. Moreover, we identified AMP-activated protein kinase (AMPK) as a novel downstream target of oncogenic PP5 and demonstrated that the antitumor mechanisms underlying PP5 inhibition involve activation of AMPK signaling. Overall, our results establish a pathological function of PP5 in hepatocarcinogenesis via affecting AMPK signaling and suggest that PP5 inhibition is an attractive therapeutic approach for HCC.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Carcinogênese/metabolismo , Carcinoma Hepatocelular/metabolismo , Neoplasias Hepáticas/metabolismo , Proteínas de Neoplasias/metabolismo , Proteínas Nucleares/metabolismo , Fosfoproteínas Fosfatases/metabolismo , Proteínas Tirosina Fosfatases não Receptoras/metabolismo , Proteínas Quinases Ativadas por AMP/química , Proteínas Quinases Ativadas por AMP/genética , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Compostos Bicíclicos Heterocíclicos com Pontes/uso terapêutico , Carcinogênese/efeitos dos fármacos , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Ativação Enzimática/efeitos dos fármacos , Indução Enzimática , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/uso terapêutico , Deleção de Genes , Células HEK293 , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas Experimentais/tratamento farmacológico , Neoplasias Hepáticas Experimentais/metabolismo , Neoplasias Hepáticas Experimentais/patologia , Camundongos Nus , Proteínas de Neoplasias/agonistas , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas de Neoplasias/genética , Estadiamento de Neoplasias , Proteínas Nucleares/antagonistas & inibidores , Proteínas Nucleares/genética , Fosfoproteínas Fosfatases/antagonistas & inibidores , Fosfoproteínas Fosfatases/genética , Proteínas Tirosina Fosfatases não Receptoras/antagonistas & inibidores , Proteínas Tirosina Fosfatases não Receptoras/genética , Interferência de RNA , Distribuição Aleatória , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/metabolismo , Análise de Sobrevida , Carga Tumoral/efeitos dos fármacos
12.
Lung Cancer ; 112: 81-89, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-29191605

RESUMO

OBJECTIVES: Non-small cell lung cancer (NSCLC) continues to be the top cause of cancer death. To improve the treatment of lung cancer, there is necessity to identify novel oncogenes and investigate their effects on lung carcinogenesis. Protein phosphatase 5 (PP5) has long been known to regulate stress-induced apoptosis and cell proliferation. Recently, PP5 has been found overexpressed and emerged as a viable therapeutic target in various human cancers, but its role in NSCLC remains elusive. MATERIALS AND METHODS: The expression of PP5 in NSCLC cell lines (A549, H358, and H460) and human tumor samples were examined. Protein phosphatase inhibitors, cantharidin and norcantharidin, were used as proof-of-concept compounds to investigate the pathological function of PP5 in NSCLC. Apoptosis and cellular signaling were analyzed. In vivo efficacy was determined in nude mice with H460 xenograft. RESULTS AND CONCLUSION: We found that PP5 was more highly expressed in human lung tumor samples than in adjacent normal tissues. Overexpression of PP5 promoted cell proliferation, colony formation, and sphere-forming ability of A549 cells. Inhibition of PP5 phosphatase activity by cantharidin induced significant apoptosis and upregulated AMP-activated protein kinase (AMPK) signaling. Importantly, we found that PP5-mediated dephosphorylation of AMPK determines the in vitro anti-NSCLC effects of cantharidin. Consistent with our in vitro data, PP5 inhibition suppressed H460 tumor growth and upregulated p-AMPK in tumor samples. Our results demonstrate that PP5 inhibition suppresses tumor growth via activating AMPK signaling. Targeting oncogenic PP5 represents an attractive therapeutic strategy for treating lung cancer.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Neoplasias Pulmonares/metabolismo , Proteínas Nucleares/antagonistas & inibidores , Fosfoproteínas Fosfatases/antagonistas & inibidores , Animais , Antineoplásicos , Apoptose , Cantaridina/farmacologia , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/patologia , Linhagem Celular Tumoral , Proliferação de Células , Sobrevivência Celular , Modelos Animais de Doenças , Inibidores Enzimáticos/farmacologia , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/patologia , Camundongos , Ensaios Antitumorais Modelo de Xenoenxerto
13.
Exp Mol Med ; 49(8): e366, 2017 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-28798401

RESUMO

Triple-negative breast cancer (TNBC) remains difficult to treat and urgently needs new therapeutic options. Nintedanib, a multikinase inhibitor, has exhibited efficacy in early clinical trials for HER2-negative breast cancer. In this study, we examined a new molecular mechanism of nintedanib in TNBC. The results demonstrated that nintedanib enhanced TNBC cell apoptosis, which was accompanied by a reduction of p-STAT3 and its downstream proteins. STAT3 overexpression suppressed nintedanib-mediated apoptosis and further increased the activity of purified SHP-1 protein. Moreover, treatment with either a specific inhibitor of SHP-1 or SHP-1-targeted siRNA reduced the apoptotic effects of nintedanib, which validates the role of SHP-1 in nintedanib-mediated apoptosis. Furthermore, nintedanib-induced apoptosis was attenuated in TNBC cells expressing SHP-1 mutants with constantly open conformations, suggesting that the autoinhibitory mechanism of SHP-1 attenuated the effects of nintedanib. Importantly, nintedanib significantly inhibited tumor growth via the SHP-1/p-STAT3 pathway. Clinically, SHP-1 levels were downregulated, whereas p-STAT3 was upregulated in tumor tissues, and SHP-1 transcripts were associated with improved disease-free survival in TNBC patients. Our findings revealed that nintedanib induces TNBC apoptosis by acting as a SHP-1 agonist, suggesting that targeting STAT3 by enhancing SHP-1 expression could be a viable therapeutic strategy against TNBC.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Indóis/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Proteína Tirosina Fosfatase não Receptora Tipo 6/metabolismo , Fator de Transcrição STAT3/metabolismo , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Animais , Antineoplásicos/uso terapêutico , Linhagem Celular Tumoral , Intervalo Livre de Doença , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Indóis/uso terapêutico , Estimativa de Kaplan-Meier , Camundongos , Camundongos Endogâmicos BALB C , Inibidores de Proteínas Quinases/uso terapêutico , Proteína Tirosina Fosfatase não Receptora Tipo 6/genética , Proteínas Tirosina Quinases/metabolismo , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Fator de Transcrição STAT3/genética , Ensaios Antitumorais Modelo de Xenoenxerto
14.
J Mol Med (Berl) ; 95(9): 965-975, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28578456

RESUMO

Triple negative breast cancer (TNBC) is an aggressive cancer for which prognosis remains poor. Combination therapy is a promising strategy for enhancing treatment efficacy. Blockade of STAT3 signaling may enhance the response of cancer cells to conventional chemotherapeutic agents. Here we used a SHP-1 agonist SC-43 to dephosphorylate STAT3 thereby suppressing oncogenic STAT3 signaling and tested it in combination with docetaxel in TNBC cells. We first analyzed messenger RNA (mRNA) expression of SHP-1 gene (PTPN6) in a public TNBC dataset (TCGA) and found that higher SHP-1 mRNA expression is associated with better overall survival in TNBC patients. Sequential combination of docetaxel and SC-43 in vitro showed enhanced anti-proliferation and apoptosis associated with decreased p-STAT3 and decreased STAT3-downstream effector cyclin D1 in the TNBC cell lines MDA-MB-231, MDA-MB-468, and HCC-1937. Ectopic expression of STAT3 reduced the increased cytotoxicity induced by the combination therapy. In addition, this sequential combination showed enhanced SHP-1 activity compared to SC-43 alone. Furthermore, the combination treatment-induced apoptosis was attenuated by small interfering RNA (siRNA) against SHP-1 or by ectopic expression of SHP-1 mutants that caused SC-43 to lose its SHP-1 agonist capability. Moreover, combination of docetaxel and SC-43 showed enhanced tumor growth inhibition compared to single-agent therapy in mice bearing MDA-MB-231 tumor xenografts. Our results suggest that the novel SHP-1 agonist SC-43 enhanced docetaxel-induced cytotoxicity by SHP-1 dependent STAT3 inhibition in human triple negative breast cancer cells. TNBC patients with high SHP-1 expressions show better survival. Docetaxel combined with SC-43 enhances cell apoptosis and reduces p-STAT3. SHP-1 inhibition reduces the enhanced effect of docetaxel-SC-43 combination. Docetaxel-SC-43 combination suppresses xenograft tumor growth and reduces p-STAT3. KEY MESSAGES: TNBC patients with high SHP-1 expressions show better survival. Docetaxel combined with SC-43 enhances cell apoptosis and reduces p-STAT3. SHP-1 inhibition reduces the enhanced effect of docetaxel-SC-43 combination. Docetaxel-SC-43 combination suppresses xenograft tumor growth and reduces p-STAT3.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Proteína Tirosina Fosfatase não Receptora Tipo 6/metabolismo , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais/efeitos dos fármacos , Taxoides/farmacologia , Neoplasias de Mama Triplo Negativas/metabolismo , Animais , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Modelos Animais de Doenças , Docetaxel , Sinergismo Farmacológico , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Camundongos , Éteres Fenílicos/farmacologia , Compostos de Fenilureia/farmacologia , Prognóstico , Proteína Tirosina Fosfatase não Receptora Tipo 6/genética , Transcrição Gênica , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/mortalidade , Ensaios Antitumorais Modelo de Xenoenxerto
15.
Cancer Lett ; 371(2): 205-13, 2016 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-26679051

RESUMO

Sorafenib is the first and currently the only standard treatment for advanced hepatocellular carcinoma (HCC). We previously developed a sorafenib derivative SC-43, which exhibits much more enhanced anti-HCC activity than sorafenib and also promotes apoptosis in sorafenib-resistant HCC cells. Herein, a novel "sorafenib plus" combination therapy was developed by coupling sorafenib treatment with SC-43. Both sorafenib and SC-43 are proven Src homology region 2 domain containing phosphatase 1 (SHP-1) agonists. The combined actions of sorafenib and SC-43 enhanced SHP-1 activity, which was associated with diminished STAT3-related signals and stronger expression of apoptotic genes above that of either drug alone, culminating in increased cell death. Decreased p-STAT3 signaling and tumor size, as well as increased SHP-1 activity were observed in mice receiving the combination therapy in a subcutaneous HCC model. More reduced orthotopic HCC tumor size and prolonged survival were also observed in mice in the combination treatment arm compared to mice in either of the monotherapy arms. These results in the preclinical setting pave the way for further clinical studies to treat unresectable HCC.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Carcinoma Hepatocelular/tratamento farmacológico , Ativadores de Enzimas/farmacologia , Neoplasias Hepáticas/tratamento farmacológico , Niacinamida/análogos & derivados , Éteres Fenílicos/farmacologia , Compostos de Fenilureia/farmacologia , Proteína Tirosina Fosfatase não Receptora Tipo 6/metabolismo , Animais , Apoptose/efeitos dos fármacos , Carcinoma Hepatocelular/enzimologia , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Ativação Enzimática , Humanos , Neoplasias Hepáticas/enzimologia , Neoplasias Hepáticas/patologia , Camundongos Nus , Niacinamida/farmacologia , Fosforilação , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais/efeitos dos fármacos , Sorafenibe , Fatores de Tempo , Carga Tumoral/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
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