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1.
Theranostics ; 9(12): 3541-3554, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31281496

RESUMO

Rationale: Advanced nasopharyngeal carcinoma (NPC) is an aggressive disease with no targeted therapies and poor outcomes. New innovative targets are urgently needed. KLF4 has been extensively studied in the context of tumors, and current data suggest that it can act as either a tissue-specific tumor-inhibiting or a tumor-promoting gene. Here, we found that KLF4 played as a tumor-promoting gene in NPC, and could be mediated by PLK1. Methods: Tissue immunohistochemistry (IHC) assay was performed to identify the role of KLF4 in NPC. Global gene expression experiments were performed to explore the molecular mechanisms underlying KLF4-dependent tumorigenesis. Small-molecule kinase inhibitor screening was performed to identify potential upstream kinases of KLF4. The pharmacologic activity of polo-like kinase inhibitor volasertib (BI6727) in vitro and in vivo was determined. Result: Our investigation showed that high expression of KLF4 was correlated with poor prognosis in NPC. Moreover, genome-wide profiling revealed that KLF4 directly activated oncogenic programmes, including gene sets associated with KRAS, VEGF, and MYC signalling. We further found that inhibition of polo-like kinase 1 could downregulate the expression of KLF4 and that PLK1 directly phosphorylated KLF4 at Ser234. Notably, phosphorylation of KLF4 by PLK1 caused the recruitment and binding of the E3 ligase TRAF6, which resulted in KLF4 K32 K63-linked ubiquitination and stabilization. Moreover, KLF4 could enhance TRAF6 expression at the transcriptional level, thus initiating a KLF4-TRAF6 feed-forward loop. Treatment with the PLK1 inhibitor volasertib (BI6727) significantly inhibited tumor growth in nude mice. Conclusion: Our study unveiled a new PLK1-TRAF6-KLF4 feed-forward loop. The resulting increase in KLF4 ubiquitination leads to stabilization and upregulation of KLF4, which leads to tumorigenesis in NPC. These results expand our understanding of the role of KLF4 in NPC and validate PLK1 inhibitors as potential therapeutic agents for NPC, especially cancer patients with KLF4 overexpression.

2.
Clin Cancer Res ; 25(14): 4530-4541, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-30940655

RESUMO

PURPOSE: Immune checkpoint blockade (ICB) therapy induces durable tumor regressions in a minority of patients with cancer. In this study, we aimed to identify kinase inhibitors that were capable of increasing the antimelanoma immunity. EXPERIMENTAL DESIGN: Flow cytometry-based screening was performed to identify kinase inhibitors that can block the IFNγ-induced PD-L1 expression in melanoma cells. The pharmacologic activities of regorafenib alone or in combination with immunotherapy in vitro and in vivo were determined. The mechanisms of regorafenib were explored and analyzed in melanoma patients treated with or without anti-PD-1 using The Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) datasets. RESULTS: Through screening of a kinase inhibitor library, we found approximately 20 agents that caused more than half reduction of cell surface PD-L1 level, and regorafenib was one of the most potent agents. Furthermore, our results showed that regorafenib, in vitro and in vivo, strongly promoted the antitumor efficacy when combined with IFNγ or ICB. By targeting the RET-Src axis, regorafenib potently inhibited JAK1/2-STAT1 and MAPK signaling and subsequently attenuated the IFNγ-induced PD-L1 and IDO1 expression without affecting MHC-I expression much. Moreover, RET and Src co-high expression was an independent unfavorable prognosis factor in melanoma patients with or without ICB through inhibiting the antitumor immune response. CONCLUSIONS: Our data unveiled a new mechanism of alleviating IFNγ-induced PD-L1 and IDO1 expression and provided a rationale to explore a novel combination of ICB with regorafenib clinically, especially in melanoma with RET/Src axis activation.

3.
Mar Drugs ; 17(2)2019 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-30678113

RESUMO

The composition of the culture medium has great influence on the metabolite production of the marine fungus Pseudallescheria boydii F44-1. By adding amino acids to GPY culture medium, two new bisindole alkaloids, pseudboindoles A and B (1 and 2), together with 11 known indole alkaloids were isolated from the culture broth. Their structures were elucidated by comprehensive analysis of the NMR, MS, IR, and UV spectra. The 3,3'-cyclohexylidenebis(1H-indole) (3) showed cytotoxic activity against various cancer cell lines.


Assuntos
Aminoácidos/química , Antineoplásicos/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Alcaloides Indólicos/farmacologia , Pseudallescheria/química , Antineoplásicos/química , Linhagem Celular Tumoral , Humanos , Alcaloides Indólicos/química , Estrutura Molecular
4.
Theranostics ; 8(6): 1494-1510, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29556337

RESUMO

Rationale: Nasopharyngeal carcinoma (NPC) is the most frequent head and neck tumor in South China. The presence of cancer stem cells (CSCs) in NPC contributes to tumor maintenance and therapeutic resistance, while the ability of CSCs to escape from the apoptosis pathway may render them the resistant property to the therapies. Inhibitor of apoptosis proteins family proteins (IAPs), which are overexpressed in nasopharyngeal carcinoma stem cells, may play an important role in maintaining nasopharyngeal cancer stem cell properties. Here, we develop a novel CSC-targeting strategy to treat NPC through inhibiting IAPs. Methods: Human NPC S-18 and S-26 cell lines were used as the model system in vitro and in vivo. Fluorescence activated cell sorting (FACS) assay was used to detect nasopharyngeal SP cells and CD44+ cells. The characteristics of CSCs were defined by sphere suspension culture, colony formation assay and cell migration. The role of XIAP on the regulation of Sox2 protein stability and ERK1-mediated phosphorylation of Sox2 signaling pathway were analyzed using immunoblotting, immunoprecipitation, immunofluorescence, phosphorylation mass spectrometry, siRNA silencing and plasmid overexpression. The correlation between XIAP and Sox2 in NPC biopsies and their role in prognosis was performed by immunohistochemistry. APG-1387 or chemotherapies-induced cell death and apoptosis in S-18 and S-26 were determined by WST, immunoblotting and flow cytometry assay. Results: IAPs, especially X chromosome-linked IAP (XIAP), were elevated in CSCs of NPC, and these proteins were critically involved in the maintenance of CSCs properties by enhancing the stability of Sox2. Mechanistically, ERK1 kinase promoted autophagic degradation of Sox2 via phosphorylation of Sox2 at Ser251 and further SUMOylation of Sox2 at Lys245 in non-CSCs. However, XIAP blocked autophagic degradation of Sox2 by inhibiting ERK1 activation in CSCs. Additionally, XIAP was positively correlated with Sox2 expression in NPC tissues, which were associated with NPC progression. Finally, we discovered that a novel antagonist of IAPs, APG-1387, exerted antitumor effect on CSCs. Also, the combination of APG-1387 with CDDP /5-FU has a synergistic effect on NPC. Conclusion: Our study highlights the importance of IAPs in the maintenance of CSCs in NPC. Thus, XIAP is a promising therapeutic target in CSCs and suggests that NPC patients may benefit from a combination treatment of APG-1387 with conventional chemotherapy.

5.
Autophagy ; 14(4): 671-684, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-28980855

RESUMO

Impaired macroautophagy/autophagy and high levels of glycolysis are prevalent in liver cancer. However, it remains unknown whether there is a regulatory relationship between autophagy and glycolytic metabolism. In this study, by utilizing cancer cells with basal or impaired autophagic flux, we demonstrated that glycolytic activity is negatively correlated with autophagy level. The autophagic degradation of HK2 (hexokinase 2), a crucial glycolytic enzyme catalyzing the conversion of glucose to glucose-6-phosphate, was found to be involved in the regulation of glycolysis by autophagy. The Lys63-linked ubiquitination of HK2 catalyzed by the E3 ligase TRAF6 was critical for the subsequent recognition of HK2 by the autophagy receptor protein SQSTM1/p62 for the process of selective autophagic degradation. In a tissue microarray of human liver cancer, the combination of high HK2 expression and high SQSTM1 expression was shown to have biological and prognostic significance. Furthermore, 3-BrPA, a pyruvate analog targeting HK2, significantly decreased the growth of autophagy-impaired tumors in vitro and in vivo (p < 0.05). By demonstrating the regulation of glycolysis by autophagy through the TRAF6- and SQSTM1-mediated ubiquitination system, our study may open an avenue for developing a glycolysis-targeting therapeutic intervention for treatment of autophagy-impaired liver cancer.

6.
Nat Commun ; 8(1): 1159, 2017 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-29079782

RESUMO

Autophagy is a degradative pathway that delivers cellular components to the lysosome for degradation. The role of autophagy in cell differentiation is poorly understood. Here we show that CaMKII can directly phosphorylate Beclin 1 at Ser90 to promote K63-linked ubiquitination of Beclin 1 and activation of autophagy. Meanwhile, CaMKII can also promote K63-linked ubiquitination of inhibitor of differentiation 1/2 (Id-1/2) by catalyzing phosphorylation of Id proteins and recruiting TRAF-6. Ubiquitinated Id-1/Id-2 can then bind to p62 and be transported to autolysosomes for degradation. Id degradation promotes the differentiation of neuroblastoma cells and reduces the proportion of stem-like cells. Our study proposes a mechanism by which autophagic degradation of Id proteins can regulate cell differentiation. This suggests that targeting of CaMKII and the regulation of autophagic degradation of Id may be an effective therapeutic strategy to induce cell differentiation in neuroblastoma.


Assuntos
Proteína Beclina-1/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Proteína 1 Inibidora de Diferenciação/metabolismo , Proteína 2 Inibidora de Diferenciação/metabolismo , Neuroblastoma/metabolismo , Animais , Autofagia , Diferenciação Celular , Fibroblastos/metabolismo , Células HEK293 , Humanos , Lisina/química , Lisossomos/metabolismo , Camundongos , Fosforilação , Proteínas de Ligação a RNA/metabolismo , Serina/química , Fator 6 Associado a Receptor de TNF/metabolismo , Ubiquitinação
7.
Chem Biodivers ; 14(3)2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27804218

RESUMO

Two new pyripyropenes, 13-dehydroxy-1,11-deacetylpyripyropene A (1) and 1-deacetylpyripyropene A (2), together with six known compounds, were isolated from a marine fungus Fusarium lateritium 2016F18-1 which was associated with the sponge Phyllospongia foliascens. Their structures were established mainly based on NMR and MS data. Their cytotoxic activities against human cancer cells CNE1, CNE2, HONE1, SUNE1, GLC82, and HL7702 were evaluated.


Assuntos
Fusarium/química , Piridinas/química , Sesquiterpenos/química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Fusarium/metabolismo , Humanos , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Conformação Molecular , Piridinas/toxicidade , Sesquiterpenos/toxicidade
8.
Oncol Lett ; 12(5): 3598-3608, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27900042

RESUMO

Dysregulation of the discoidin domain receptors (DDRs) has been implicated in the development of numerous types of tumors, including head and neck cancer, and nasopharyngeal, breast, ovarian and esophageal carcinomas. Furthermore, agents that inhibit DDR1 activity are hypothesized to be useful for the treatment of nasopharyngeal carcinoma (NPC). The aim of the present study was to evaluate the effect of the DDR1 inhibitory (3-(2-(pyrazolo(1,5-a)pyrimidin-6-yl)-ethynyl)benzamide compound, 7RH, in NPC cells both in vitro and in vivo, and its effect when used in combination with dasatinib, a SRC family kinase (SFK) inhibitor. The effects of 7RH alone or in combination with dasatinib on cell viability were assessed using MTT assays and apoptosis was detected by flow cytometry. In addition, western blotting was performed to analyze the relative protein expression levels of cell cycle-associated genes in human NPC cell lines (CNE1, CNE2, HONE1 and SUNE1). Cell migration was also assessed using cell adhesion assays. Furthermore, tumor xenografts of CNE2 NPC cells were established in nude mice and the growth inhibitory effects of 7RH treatment alone or in combination with dasatinib were evaluated. Finally, knockdown of DDR1 protein expression was achieved by transfection of CNE2 cells with DDR1-specific small interfering RNA. Treatment with 7RH effectively suppressed the proliferation and induced the apoptosis of NPC cells. In addition, the Janus kinase 1 (JAK1)/signal transducer and activator of transcription (STAT3) signaling pathway was downregulated by 7RH, whereas the activities of the Ras/Raf/mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) and phosphoinositide 3-kinase (PI3K)/AKT signaling pathways were upregulated in response to 7RH treatment. Furthermore, the expression levels of phosphorylated SRC were increased in NPC cells treated with 7RH; thus indicating that SRC exhibits a vital function in the resistance of NPC cells to 7RH via activation of the PI3K/AKT signaling pathway. The results of the present study indicate that DDR1 and SFK inhibition may present a potential therapeutic strategy for patients with NPC.

9.
Mar Drugs ; 14(9)2016 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-27571085

RESUMO

By the method of ¹H NMR prescreening and tracing the diagnostic proton signals of the methyl groups, three additional new triquinane-type sesquiterpenoids-chondrosterins K-M (1-3) and the known sesquiterpenoid anhydroarthrosporone (4)-were isolated from the marine fungus Chondrostereum sp. Their structures were elucidated on the basis of MS, 1D, and 2D NMR data. Chondrosterin K is a rare hirsutane sesquiterpenoid, in which a methyl group was migrated from C-2 to C-6 and has a double bond between C-2 and C-3. Compounds 1-3 showed significant cytotoxicities against various cancer cell lines in vitro.


Assuntos
Antibióticos Antineoplásicos/farmacologia , Polyporales/química , Sesquiterpenos/farmacologia , Animais , Antozoários/microbiologia , Antibióticos Antineoplásicos/química , Linhagem Celular Tumoral , Fermentação , Humanos , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Conformação Molecular , Água do Mar/microbiologia , Sesquiterpenos/química , Sesquiterpenos/isolamento & purificação , Espectrometria de Massas por Ionização por Electrospray
10.
Oncotarget ; 6(19): 17491-500, 2015 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-26036637

RESUMO

The combination of time and order-dependent chemotherapeutic strategies has demonstrated enhanced efficacy in killing cancer cells while minimizing adverse effects. However, the precise mechanism remains elusive. Our results showed that pre-treatment of MCF-7 and MDA-MB-468 cells with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor erlotinib or lapatinib significantly enhanced the cytotoxic effects of DNA-damaging agents compared to coadministration of the EGFR inhibitor and DNA-damaging agent. Sequential application of erlotinib and doxorubicin increased activated caspase-8 by promoting pro-caspase-8 homodimerization and autocatalytical cleavage, whereas coadministration did not. We found that EGFR inhibitors promoted pro-caspase-8 homodimerization by inhibiting ERK pathway signaling, while doxorubicin promoted it. Our data highlight that ERK has the potential to inhibit the formation of pro-caspase-8 homodimers by phosphorylating pro-caspase-8 at S387. In conclusion, the pretreatment of EGFR tyrosine kinase inhibitors promote pro-caspase-8 dimerization that sensitizes cancer cells to DNA-damaging agents. Our findings provide rationale for novel strategies for the implementation of combined targeted and cytotoxic chemotherapy within a new framework of time and order-dependent therapy.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Apoptose/efeitos dos fármacos , Neoplasias da Mama/metabolismo , Caspase 8/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Multimerização Proteica , Western Blotting , Linhagem Celular Tumoral , Dano ao DNA , Doxorrubicina/administração & dosagem , Receptores ErbB/antagonistas & inibidores , Cloridrato de Erlotinib/administração & dosagem , Humanos , Imunoprecipitação , Lapatinib , Quinazolinas/administração & dosagem , Transfecção
11.
Nat Commun ; 6: 7215, 2015 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-26008601

RESUMO

Beclin 1, a protein essential for autophagy, regulates autophagy by interacting with Vps34 and other cofactors to form the Beclin 1 complex. Modifications of Beclin 1 may lead to the induction, inhibition or fine-tuning of the autophagic response under a variety of conditions. Here we show that Beclin 1 is acetylated by p300 and deacetylated by SIRT1 at lysine residues 430 and 437. In addition, the phosphorylation of Beclin 1 at S409 by CK1 is required for the subsequent p300 binding and Beclin 1 acetylation. Beclin 1 acetylation inhibits autophagosome maturation and endocytic trafficking by promoting the recruitment of Rubicon. In tumour xenografts, the expression of 2KR mutant Beclin 1 (substitution of K430 and K437 to arginines) leads to enhanced autophagosome maturation and tumour growth suppression. Therefore, our study identifies an acetylation-dependent regulatory mechanism governing Beclin 1 function in autophagosome maturation and tumour growth.


Assuntos
Proteínas Reguladoras de Apoptose/metabolismo , Autofagia , Carcinogênese , Proteínas de Membrana/metabolismo , Acetilação , Animais , Proteína Beclina-1 , Caseína Quinase I/metabolismo , Feminino , Células HEK293 , Células HeLa , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Células MCF-7 , Camundongos Nus , Fosforilação , Processamento de Proteína Pós-Traducional , Sirtuína 1/metabolismo , Fatores de Transcrição de p300-CBP/metabolismo
12.
Oncotarget ; 6(7): 5134-46, 2015 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-25762617

RESUMO

Dual PI3K/mTOR(phosphatidylinositol 3-kinase/mammalian target of rapamycin) inhibitors are being evaluated clinically for the treatment of tumors with a hyperactivated PI3K/mTOR pathway. However, unexpected outcomes were obtained in clinical studies of cancer patients with an aberrant PI3K pathway. In clinical trials, applicable combination regimens are not yet available. In this study, using an integrated analysis of acquired BEZ235-resistant nasopharyngeal carcinoma cells, we demonstrate that DNA methyltransferase is a key modulator and a common node upstream of the AKT/mTOR and PDK1/MYC pathways, which are activated in cancer cells with acquired BEZ235 resistance. DNA methyltransferases were upregulated and induced PTEN and PPP2R2B gene hypermethylation, which downregulated their expression in BEZ235-resistant cancer cells. Reduced PTEN and PPP2R2B expression correlated with activated AKT/mTOR and PDK1/MYC pathways and conferred considerable BEZ235 resistance in nasopharyngeal carcinoma. Targeting methyltransferases in combination with BEZ235 sensitized BEZ235-resistant cells to BEZ235 in vitro and in vivo, suggesting the potential clinical application of this strategy to overcome BEZ235 resistance.


Assuntos
DNA (Citosina-5-)-Metiltransferases/antagonistas & inibidores , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Neoplasias Nasofaríngeas/tratamento farmacológico , Fosfatidilinositol 3-Quinases/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Animais , Antineoplásicos/farmacologia , Apoptose , Western Blotting , Ciclo Celular , Proliferação de Células , DNA (Citosina-5-)-Metiltransferases/genética , DNA (Citosina-5-)-Metiltransferases/metabolismo , Metilação de DNA , Feminino , Humanos , Imidazóis/farmacologia , Técnicas Imunoenzimáticas , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Neoplasias Nasofaríngeas/metabolismo , Neoplasias Nasofaríngeas/patologia , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , PTEN Fosfo-Hidrolase/genética , PTEN Fosfo-Hidrolase/metabolismo , Fosfatidilinositol 3-Quinases/antagonistas & inibidores , Fosfatidilinositol 3-Quinases/genética , Proteína Fosfatase 2/genética , Proteína Fosfatase 2/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Quinolinas/farmacologia , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Serina-Treonina Quinases TOR/antagonistas & inibidores , Serina-Treonina Quinases TOR/genética , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
13.
Oncotarget ; 6(9): 6944-58, 2015 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-25749514

RESUMO

Side population (SP) contains cancer stem-like cells (CSLCs). In this study, we characterized SP cells from nasopharyngeal carcinoma (NPC) cell lines and found that SP cells had a higher self-renewal ability in vitro and greater tumorigenicity in vivo. The AKT pathway was activated in NPC SP cells. DC120, a 2-pyrimidyl-5-amidothiazole inhibitor of the ATP binding site of AKT, inhibited phosphorylation of FKHRL1 and GSK-3ß. DC120 inhibited SP fraction, the sphere-forming ability in vitro and growth of primary xenografts as well as secondary xenografts' tumor recurrence. This inhibition was accompanied by reduced expression of stem-related gene Sox2 due to induction of p27 and miR-30a. A combination of DC120 and CDDP more effectively inhibited NPC cells compared with monotherapy in vitro and in vivo. Clinical evaluation of DC120 is warranted.


Assuntos
Regulação Neoplásica da Expressão Gênica , Neoplasias Nasofaríngeas/enzimologia , Células-Tronco Neoplásicas/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Pirimidinas/química , Fatores de Transcrição SOXB1/metabolismo , Tiazóis/química , Trifosfato de Adenosina/química , Animais , Antineoplásicos/química , Sítios de Ligação , Carcinoma , Separação Celular , Regulação para Baixo , Citometria de Fluxo , Inativação Gênica , Quinase 3 da Glicogênio Sintase/metabolismo , Glicogênio Sintase Quinase 3 beta , Humanos , Concentração Inibidora 50 , Camundongos , Camundongos SCID , Carcinoma Nasofaríngeo , Recidiva Local de Neoplasia , Fenótipo , Fosforilação , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
14.
Autophagy ; 11(2): 239-52, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25701194

RESUMO

PTEN (phosphatase and tensin homolog), a tumor suppressor frequently mutated in human cancer, has various cytoplasmic and nuclear functions. PTEN translocates to the nucleus from the cytoplasm in response to oxidative stress. However, the mechanism and function of the translocation are not completely understood. In this study, topotecan (TPT), a topoisomerase I inhibitor, and cisplatin (CDDP) were employed to induce DNA damage. The results indicate that TPT or CDDP activates ATM (ATM serine/threonine kinase), which phosphorylates PTEN at serine 113 and further regulates PTEN nuclear translocation in A549 and HeLa cells. After nuclear translocation, PTEN induces autophagy, in association with the activation of the p-JUN-SESN2/AMPK pathway, in response to TPT. These results identify PTEN phosphorylation by ATM as essential for PTEN nuclear translocation and the subsequent induction of autophagy in response to DNA damage.


Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Autofagia/efeitos dos fármacos , Dano ao DNA , PTEN Fosfo-Hidrolase/metabolismo , Transporte Ativo do Núcleo Celular/efeitos dos fármacos , Antineoplásicos/farmacologia , Autofagia/fisiologia , Cisplatino/farmacologia , Humanos , Fosforilação/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Inibidores da Topoisomerase I/farmacologia , Topotecan/farmacologia , Proteínas Supressoras de Tumor/metabolismo
15.
Molecules ; 19(2): 1820-7, 2014 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-24509722

RESUMO

Bioassay-guided fractionation of an ethanol extract of the pericarps of Garcinia mangostana led to the isolation of two new prenylated xanthones, named 1,3,7-trihydroxy-2-(3-methyl-2-butenyl)-8-(3-hydroxy-3-methylbutyl)-xanthone (1) and 1,3,8-trihydroxy-2-(3-methyl-2-butenyl)-4-(3-hydroxy-3-methylbutanoyl)-xanthone (2), together with the five known compounds garcinones C (3) and D (4), gartanin (5), xanthone I (6), and γ-mangostin (7). Their structures were elucidated primarily based on MS and NMR data. Compounds 1-7 showed significant cytotoxic activities against various human cancer cell lines.


Assuntos
Garcinia mangostana/química , Neoplasias/tratamento farmacológico , Xantonas/química , Linhagem Celular Tumoral/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Frutas/química , Humanos , Estrutura Molecular , Extratos Vegetais/química , Xantonas/isolamento & purificação , Xantonas/farmacologia
16.
Life Sci ; 93(18-19): 655-63, 2013 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-24044886

RESUMO

AIM: Excisanin A, a diterpenoid compound purified from Isodon macrocalyxin D, has anti-cancer properties with little toxicity. In this study, the anti-invasive effects of excisanin A on breast cancer cells and its molecular mechanism of action were investigated. MAIN METHODS: MTT, wound healing, transwell chamber and cell adhesion assays were utilized to investigate the effects of excisanin A on MDA-MB-231 and SKBR3 cells. Western blotting, real-time PCR, RNA interference and luciferase reporter assays were employed to determine the molecular mechanism of action of excisanin A. KEY FINDINGS: Treating MDA-MB-231 and SKBR3 cells with 10-40µM excisanin A significantly inhibited cell migration and invasion and suppressed the mRNA and protein levels of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) in a dose-dependent manner. Excisanin A efficiently abolished integrin ß1 expression and reduced the phosphorylation of the downstream kinases focal adhesion kinase (FAK) and Src. Excisanin A inhibited the phosphorylation of phosphoinositide 3-kinase (PI3K), AKT and glycogen synthase kinase 3 beta (GSK3ß) and down-regulated ß-catenin expression and the luciferase activity of the transcription factor LEF-1. Moreover, treating breast cancer cells with siRNA targeting integrin ß1 inhibited cell invasion and migration. SIGNIFICANCE: These results demonstrated that excisanin A inhibited invasion by suppressing MMP-2 and MMP-9 expression; the integrin ß1/FAK/PI3K/AKT/ß-catenin signaling pathway was involved in this process. Therefore, excisanin A might be a potential anti-metastatic chemotherapeutic agent for the treatment of breast cancer.


Assuntos
Neoplasias da Mama/metabolismo , Movimento Celular/efeitos dos fármacos , Diterpenos/farmacologia , Quinase 1 de Adesão Focal/antagonistas & inibidores , Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Proteínas de Membrana/antagonistas & inibidores , Fosfatidilinositol 3-Quinases/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , beta Catenina/antagonistas & inibidores , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Movimento Celular/fisiologia , Diterpenos/isolamento & purificação , Diterpenos/uso terapêutico , Feminino , Quinase 1 de Adesão Focal/biossíntese , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/biossíntese , Proteínas de Membrana/biossíntese , Invasividade Neoplásica/patologia , Invasividade Neoplásica/prevenção & controle , Fosfatidilinositol 3-Quinases/fisiologia , Proteínas Proto-Oncogênicas c-akt/biossíntese , beta Catenina/fisiologia
17.
PLoS One ; 8(3): e59879, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23533654

RESUMO

Phosphoinositide 3-kinase (PI3K)/AKT/mammalian target of rapamycin inhibitor (mTOR) pathway is often constitutively activated in human tumor cells and thus has been considered as a promising drug target. To ascertain a therapeutical approach of nasopharyngeal carcinoma (NPC), we hypothesized NVP-BEZ235, a novel and potent imidazo[4,5-c] quinolone derivative, that dually inhibits both PI3K and mTOR kinases activities, had antitumor activity in NPC. Expectedly, we found that NVP-BEZ235 selectively inhibited proliferation of NPC cells rather than normal nasopharyngeal cells using MTT assay. In NPC cell lines, with the extended exposure, NVP-BEZ235 selectively inhibited proliferation of NPC cells harboring PIK3CA mutation, compared to cells with wild-type PIK3CA. Furthermore, exposure of NPC cells to NVP-BEZ235 resulted in G1 growth arrest by Propidium iodide uptake assay, reduction of cyclin D1and CDK4, and increased levels of P27 and P21 by Western blotting, but negligible apoptosis. Moreover, we found that cisplatin (CDDP) activated PI3K/AKT and mTORC1 pathways and NVP-BEZ235 alleviated the activation by CDDP through dually targeting PI3K and mTOR kinases. Also, NVP-BEZ235 combining with CDDP synergistically inhibited proliferation and induced apoptosis in NPC cells. In CNE2 and HONE1 nude mice xenograft models, orally NVP-BEZ235 efficiently attenuated tumor growth with no obvious toxicity. In combination with NVP-BEZ235 and CDDP, there was dramatic synergy in shrinking tumor volumes and inducing apoptosis through increasing Noxa, Bax and decreasing Mcl-1, Bcl-2. Based on the above results, NVP-BEZ235, which has entered phase I/II clinical trials in patients with advanced solid tumors, has a potential as a monotherapy or in combination with CDDP for NPC treatment.


Assuntos
Cisplatino/uso terapêutico , Imidazóis/uso terapêutico , Neoplasias Nasofaríngeas/tratamento farmacológico , Fosfatidilinositol 3-Quinases/metabolismo , Quinolinas/uso terapêutico , Animais , Apoptose/efeitos dos fármacos , Western Blotting , Butadienos/farmacologia , Butadienos/uso terapêutico , Carcinoma , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Cisplatino/farmacologia , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/uso terapêutico , Feminino , Humanos , Imidazóis/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Carcinoma Nasofaríngeo , Neoplasias Nasofaríngeas/enzimologia , Neoplasias Nasofaríngeas/metabolismo , Nitrilos/farmacologia , Nitrilos/uso terapêutico , Fosfatidilinositol 3-Quinases/antagonistas & inibidores , Quinolinas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/antagonistas & inibidores , Ensaios Antitumorais Modelo de Xenoenxerto
18.
J Transl Med ; 11: 32, 2013 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-23394457

RESUMO

BACKGROUND: Hirsutanol A is a novel sesquiterpene compound purified from fungus Chondrostereum sp. in Sarcophyton tortuosum. Our previous studies had demonstrated that hirsutanol A exhibited potent cytotoxic effect on many kinds of cancer cell lines. In the current study, the antitumor activity of hirsutanol A and its molecular mechanisms were investigated. METHODS: Hirsutanol A induced growth inhibition and apoptotic cell death of human colon cancer SW620 cells and human breast cancer MDA-MB-231cells were determined using MTT assay and flow cytometry assay, respectively. The effect of hirsutanol A on intrinsic ROS level and change in mitochondrial membrane potential (△ψm) of different cell lines were also measured by flow cytometry assay. The function of JNK was compromised by JNK siRNA or JNK inhibitor SP600125. The expression of cytochrome c, p-JNK, p-c-Jun after treatment with hirsutanol A were detected by Western blot analysis. Finally, the in vivo anti-tumor effect of hirsutanol A was examined in human cancer cell SW620 xenograft model. RESULTS: The results showed that hirsutanol A significantly induced apoptosis, mitochondrial-independent increase of Reactive Oxygen Species (ROS) level, change of mitochondrial membrane potential, release of cytochrome c in human cancer cells. Preventing increase of ROS level using the potent antioxidant N-acetyl-L-cysteine (NAC) markedly decreased hirsutanol A-induced apoptosis. In addition, JNK signaling pathway was activated by hirsutanol A through elevating ROS level. Blockade of JNK signaling pathway by JNK specific inhibitor SP600125 enhanced apoptosis and hirsutanol A-induced ROS accumulation. Also, hirsutanol A exhibited antitumor activity in human cancer cell SW620 xenograft model. CONCLUSION: These data suggested that hirsutanol A inhibited tumor growth through triggering ROS production and apoptosis.


Assuntos
Agaricales/metabolismo , Apoptose , Espécies Reativas de Oxigênio/metabolismo , Sesquiterpenos/farmacologia , Animais , Morte Celular , Linhagem Celular Tumoral , Citocromos c/metabolismo , Citosol/metabolismo , Citometria de Fluxo , Humanos , Potenciais da Membrana , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Mitocôndrias/metabolismo , Transplante de Neoplasias , Transdução de Sinais , Sais de Tetrazólio/farmacologia , Tiazóis/farmacologia
19.
Cell Signal ; 25(1): 150-8, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22982090

RESUMO

JNK signaling functions to induce defense mechanisms that protect organisms against a variety of different situations. The sestrin 2 gene, a p53-regulated member of the sestrins family, which lead to AMPK-dependent inhibition of TOR signaling, emerges as a novel player in autophagy induction. However, the relationship between JNK pathway, autophagy induction and sestrin 2 expression remains elusive. In the present study, we identify JNK as a regulator of autophagy in nasopharyngeal carcinoma cell lines CNE1 and CNE2 exposed to excisanin A or serum deprivation and demonstrate that activation of JNK can cause upregulation of sestrin 2 expression, which could be blocked by specific siRNAs directed against JNK1/2 or c-Jun. Chromatin immunoprecipitation and luciferase reporter analysis revealed that c-Jun was transcriptionally involved in the regulation of sestrin 2. Furthermore, knockdown of sestrin 2 by siRNAs similarly inhibited autophagy induction. Moreover, silencing the expression of autophagy related gene ATG5 or sestrin 2 significantly decreases cell death induced by excisanin A. Our results therefore identify JNK as a novel mediator of sestrin 2 expression, which plays a key role in autophagy induction following anticancer therapies in cancers.


Assuntos
Autofagia/efeitos dos fármacos , Diterpenos/farmacologia , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Proteínas Nucleares/metabolismo , Proteína 5 Relacionada à Autofagia , Linhagem Celular Tumoral , Imunoprecipitação da Cromatina , Ativação Enzimática/efeitos dos fármacos , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Proteínas Associadas aos Microtúbulos/metabolismo , Proteína Quinase 8 Ativada por Mitógeno/antagonistas & inibidores , Proteína Quinase 8 Ativada por Mitógeno/genética , Proteína Quinase 8 Ativada por Mitógeno/metabolismo , Proteína Quinase 9 Ativada por Mitógeno/antagonistas & inibidores , Proteína Quinase 9 Ativada por Mitógeno/genética , Proteína Quinase 9 Ativada por Mitógeno/metabolismo , Proteínas Nucleares/antagonistas & inibidores , Proteínas Nucleares/genética , Fosforilação , Proteínas Proto-Oncogênicas c-jun/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-jun/genética , Proteínas Proto-Oncogênicas c-jun/metabolismo , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Regulação para Cima/efeitos dos fármacos
20.
PLoS One ; 7(9): e45058, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23024792

RESUMO

BACKGROUND: Topotecan produces DNA damage that induces autophagy in cancer cells. In this study, sensitising topotecan to colon cancer cells with different P53 status via modulation of autophagy was examined. METHODOLOGY/PRINCIPAL FINDINGS: The DNA damage induced by topotecan treatment resulted in cytoprotective autophagy in colon cancer cells with wild-type p53. However, in cells with mutant p53 or p53 knockout, treatment with topotecan induced autophagy-associated cell death. In wild-type p53 colon cancer cells, topotecan treatment activated p53, upregulated the expression of sestrin 2, induced the phosphorylation of the AMPKα subunit at Thr172, and inhibited the mTORC1 pathway. Furthermore, the inhibition of autophagy enhanced the anti-tumour effect of topotecan treatment in wild-type p53 colon cancer cells but alleviated the anti-tumour effect of topotecan treatment in p53 knockout cells in vivo. CONCLUSIONS/SIGNIFICANCE: These results imply that the wild-type p53-dependent induction of cytoprotective autophagy is one of the cellular responses that determines the cellular sensitivity to the DNA-damaging drug topotecan. Therefore, our study provides a potential therapeutic strategy that utilises a combination of DNA-damaging agents and autophagy inhibitors for the treatment of colon cancer with wild-type p53.


Assuntos
Antineoplásicos/farmacologia , Autofagia/efeitos dos fármacos , Autofagia/genética , Neoplasias do Colo/genética , Mutação , Topotecan/farmacologia , Proteína Supressora de Tumor p53/genética , Proteínas Quinases Ativadas por AMP/metabolismo , Animais , Linhagem Celular Tumoral , Neoplasias do Colo/metabolismo , Resistencia a Medicamentos Antineoplásicos/genética , Técnicas de Inativação de Genes , Células HCT116 , Humanos , Alvo Mecanístico do Complexo 1 de Rapamicina , Camundongos , Camundongos Nus , Complexos Multiproteicos/metabolismo , Proteínas Nucleares/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
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