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Tumor necrosis factor-related apoptosis-induced ligand (TRAIL) shows little or no toxicity in most normal cells and preferentially induces apoptosis in a variety of malignant cells. However, patients develop resistance to TRAIL, therefore, sensitizing agents that can sensitize the tumor cells to TRAIL-mediated apoptosis are necessary. In this study, we investigated the effect of 2-(3-hydroxyphenyl)-5-methylnaphthyridin-4-one (CSC-3436), an useful flavonoid, to overcome the TRAIL-resistant triple negative breast cancer (TNBC) cells. We found that CSC-3436 potentiated TRAIL-induced apoptosis in TRAIL-resistant TNBC cells and this correlated with the upregulation of death receptors (DR)-5 and down-regulation of decreased decoy receptor (DcR)-1 expression. When examined for its mechanism, we found that the decreased expression of anti-apoptotic proteins c-FLIPS/L, Bcl-Xl, Bcl-2, Survivin, and XIAP. CSC-3436 would increase the expression of Bax and promoted the cleavage of bid. In addition, the induction of DR5 by CSC-3436 was found to be dependent on the modulation of reactive oxygen species (ROS)/p38/C/EBP-homologous protein (CHOP) signaling pathways. Overall, our results indicated that CSC-3436 could potentiate the apoptotic effects of TRAIL through down-regulation of cell survival proteins and upregulation of DR5 via the ROS-mediated upregulation of CHOP protein.
Assuntos
Receptores do Ligante Indutor de Apoptose Relacionado a TNF , Neoplasias de Mama Triplo Negativas , Apoptose , Linhagem Celular Tumoral , Humanos , Ligantes , Naftiridinas , Espécies Reativas de Oxigênio , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/genética , Ligante Indutor de Apoptose Relacionado a TNF , Fator de Transcrição CHOP/genéticaRESUMO
This paper investigates a novel joint problem of routing, scheduling, and channel allocation for single-radio multichannel wireless mesh networks in which multiple channel widths can be adjusted dynamically through a new software technology so that more concurrent transmissions and suppressed overlapping channel interference can be achieved. Although the previous works have studied this joint problem, their linear programming models for the problem were not incorporated with some delicate constraints. As a result, this paper first constructs a linear programming model with more practical concerns and then proposes a simulated annealing approach with a novel encoding mechanism, in which the configurations of multiple time slots are devised to characterize the dynamic transmission process. Experimental results show that our approach can find the same or similar solutions as the optimal solutions for smaller-scale problems and can efficiently find good-quality solutions for a variety of larger-scale problems.
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Redes de Comunicação de Computadores , Modelos Teóricos , Tecnologia sem Fio , AlgoritmosRESUMO
UNLABELLED: There are four types of PM10 (particulate matter with an aerodynamic diameter <10 microm) episodes that occur frequently in central Taiwan: long-range transport with dust storms (DS), long-range transport with frontal pollution (FP), river dust (RD), and stagnant weather (SW). During the periods of the four episodes, poor visibility usually results. Multiple linear regression was applied to visibility using eight potential influential variables (temperature, relative humidity, wind speed, PM2.5, PM2.5-10, SO2, NO2, and NO) as independent variables. Of the eight variables, PM2.5 showed the greatest explainable percentage of about 48.6% and 58.1% for Taichung and Wuchi stations, respectively. This suggested that PM2.5 was the most important contributor to reduced visibility. Compared with other type of episodes, the aerosols tended to be offine size during the SWepisodes. This is the main reason that the poorest visibility occurred during the SWepisodes. Good correlation between visibility and secondary inorganic salts (NH4+, NO3, and SO4(2-)) were found at Taichung station (r = 0.71) and Wuchi station (r = 0.81), suggesting that secondary inorganic salts did contribute significantly to the degradation ofvisibility. The visibility degradation due to the effects ofNO3- was much higher than that due to SO4(2-) and NH4+ in the urban area, whereas the visibility degradation due to the effects of NO3 , SO42-, and NH4+ did not show significant diference in the rural area. IMPLICATIONS: Of the eight potential influential variables, PM2.5 showed the greatest effects on reduced visibility. Compared with other type of episodes, the aerosols tend to be fine size during the episodes of stagnant weather. This is the main reason why the poorest visibility occurred during the SW episodes. Good correlations between visibility and secondary inorganic salts (NH4+, NO3-, and SO4(2-)) suggested that secondary inorganic salts did contribute significantly to the degradation of visibility. Among the three inorganic salts, nitrates played a leading role for visibility degradation in urban areas in central Taiwan.
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Poluentes Atmosféricos/química , Monitoramento Ambiental/métodos , Tamanho da Partícula , Material Particulado , TaiwanRESUMO
Daily and hourly average data from nine air-quality monitoring stations distributed across central Taiwan, which include ten items (i.e., PM10, PM2.5, wind direction, wind speed, temperature, relative humidity, SO2, NO2, NO, and CO), were collected from 2005 to 2009. Four episode types: long-range transport with dust storms (DS), long-range transport with frontal pollution (FP), river dust (RD), and stagnant weather (SW), and one mixed type of episode were identified. Of these four episode types, the SW was the dominant type, averaging about 70%. The mean ratio of PM2.5/PM10 was the lowest during the RD episodes (0.42), while the mean ratio of PM2.5/PM10 was the highest during the SW episodes (0.64). Fine aerosol (PM2.5) and coarse aerosol (PM10-2.5) samples were collected by high-volume samplers for chemical composition analysis, from only three stations (Douliou, Lunbei, and Siansi) during the days of SW, RD, DS, and FP. The concentrations of PM2.5 and three ionic species (NH4âº, NO3â», and SO4²â») all showed significant differences among the four episode types. The highest levels of NO3â» (12.1 µg/m(3)) and SO4²â» (20.5 µg/m(3)) were found during the SW and FP episodes, respectively. A comparison on the spatial similarity of aerosol compositions among the episodes and/or non-episodes (control) was characterized by the coefficient of divergence (CD). The results showed higher CD values in PM10-2.5 than in PM2.5, and the CD values between RD episodes and the other three episodes were higher than those between two types of episode for the other three episodes. The ratios of SOR (sulfur oxidation ratio), SO4²â»/EC (elemental carbon), NOR (nitrogen oxidation ratio), and NO3â»/EC showed that sulfate formation was most rapid during the FP, while nitrate formation was most rapid during the SW.
Assuntos
Aerossóis/análise , Poluentes Atmosféricos/análise , Poluição do Ar/estatística & dados numéricos , Monitoramento Ambiental , Material Particulado/análise , Estações do Ano , Taiwan , Tempo (Meteorologia)RESUMO
The number of people suffering from diabetes in Taiwan has continued to rise in recent years. According to the statistics of the International Diabetes Federation, about 537 million people worldwide (10.5% of the global population) suffer from diabetes, and it is estimated that 643 million people will develop the condition (11.3% of the total population) by 2030. If this trend continues, the number will jump to 783 million (12.2%) by 2045. At present, the number of people with diabetes in Taiwan has reached 2.18 million, with an average of one in ten people suffering from the disease. In addition, according to the Bureau of National Health Insurance in Taiwan, the prevalence rate of diabetes among adults in Taiwan has reached 5% and is increasing each year. Diabetes can cause acute and chronic complications that can be fatal. Meanwhile, chronic complications can result in a variety of disabilities or organ decline. If holistic treatments and preventions are not provided to diabetic patients, it will lead to the consumption of more medical resources and a rapid decline in the quality of life of society as a whole. In this study, based on the outpatient examination data of a Taipei Municipal medical center, 15,000 women aged between 20 and 80 were selected as the subjects. These women were patients who had gone to the medical center during 2018-2020 and 2021-2022 with or without the diagnosis of diabetes. This study investigated eight different characteristics of the subjects, including the number of pregnancies, plasma glucose level, diastolic blood pressure, sebum thickness, insulin level, body mass index, diabetes pedigree function, and age. After sorting out the complete data of the patients, this study used Microsoft Machine Learning Studio to train the models of various kinds of neural networks, and the prediction results were used to compare the predictive ability of the various parameters for diabetes. Finally, this study found that after comparing the models using two-class logistic regression as well as the two-class neural network, two-class decision jungle, or two-class boosted decision tree for prediction, the best model was the two-class boosted decision tree, as its area under the curve could reach a score of 0.991, which was better than other models.
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Background: Previous studies have identified three single nucleotide polymorphisms (SNPs): GALNT14-rs9679162, WWOX-rs13338697 and rs6025211. Their genotypes are associated with therapeutic outcomes in hepatocellular carcinoma (HCC). Herein, we examined whether these SNP genotypes could predict the clinical outcome of HCC patients treated with ADI-PEG 20. Methods: Totally 160 patients with advanced HCC, who had previously been enrolled in clinical trials, including 113 receiving ADI-PEG 20 monotherapy (cohort-1) and 47 receiving FOLFOX/ADI-PEG 20 combination treatment (cohort-2), were included retrospectively. Results: The WWOX-rs13338697-GG genotype was associated with favorable overall survival in cohort-1 patients (P = 0.025), whereas the rs6025211-TT genotype was associated with unfavorable time-to-tumor progression in cohort-1 (P = 0.021) and cohort-1 plus 2 patients (P = 0.008). As ADI-PEG 20 can reduce plasma arginine levels, we examined its pretreatment levels in relation to the WWOX-rs13338697 genotypes. Pretreatment plasma arginine levels were found to be significantly higher in patients carrying the WWOX-rs13338697-GG genotype (P = 0.006). We next examined the association of the WWOX-rs13338697 genotypes with WWOX tissue protein levels in 214 paired (cancerous/noncancerous) surgically resected HCC tissues (cohort-3). The WWOX-rs13338697-GG genotype was associated with decreased tissue levels of WWOX and ASS1. Mechanistic studies showed that WWOX and ASS1 levels were downregulated in hypoxic HCC cells. Silencing WWOX to mimic low WWOX protein expression in HCC in patients with the WWOX-rs13338697-GG genotype, enhanced HIF1A increment under hypoxia, further decreased ASS1, and increased cell susceptibility to ADI-PEG 20. Comclusion: In summary, the WWOX-rs13338697 and rs6025211 genotypes predicted treatment outcomes in ADI-PEG 20-treated advanced HCC patients. The WWOX-rs13338697-GG genotype was associated with lower tissue WWOX and ASS1 levels and higher pretreatment plasma arginine levels, resembling an arginine auxotrophic phenotype requires excessive extracellular arginine supply. Silencing WWOX to mimic HCC with the WWOX-rs13338697-GG genotype further stimulated HCC cell response to hypoxia through increased HIF1A expression, leading to further reduction of ASS1 and thus increased cell susceptibility to ADI-PEG 20.
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A new efficient Schiff base sensor SB3 for fluorescent and colorimetric "naked-eye" "turn-on" sensing of cyanide anion (CN-) with excellent sensitivity and selectivity was developed. The 4,4'-(perfluoropropane-2,2-diyl)bisphenol group and two phenyl groups were covalently linked by two Câ¯=â¯N bonds to extend the conjugation length. The four hydroxyl groups can improve the water solubility of the SB3 sensor. The SB3 sensor exhibited high specificity towards CN- by interrupting its intramolecular charge transfer, resulting in a color change and remarkable "turn-on" green fluorescence emission. The sensing mechanism is caused by the nucleophilic addition of CN- toward imine groups of the SB3 sensor, leading to breaks of the conjugation, fluorescent spectral changes, and color change. It was confirmed by 1H NMR titration and Mass spectra. The detection limits for CN- and Al3+obtained by fluorescence spectrum are 0.80⯵M and 0.25⯵M, respectively. The SB3 sensor can act as an efficient chemical sensor for detecting the CN- and Al3+ ions under common environmental and physiological conditions (pH 5-12). Besides, the sensor can also detect CN- in food materials (such as sprouting potatoes and cassava flour) and imaging CN-in living cells with strong "turn-on" fluorescence at 490â¯nm. SB3 is an excellent CN- sensor that exhibits some advantages, including easy synthesis, distinct fluorescence and color change, high selectivity, low detection limit, and good anti-interference ability to analyze solution and food samples, together with fluorescence cell imaging.
Assuntos
Colorimetria , Cianetos , Alumínio , Corantes Fluorescentes , Bases de Schiff , Espectrometria de FluorescênciaRESUMO
Triple negative breast cancer (TNBC) is one of the leading causes of cancer death in the world and lacks an effective targeted therapy. G-protein-coupled receptor 161 (GPR161) has been demonstrated to perform the functional regulations on TNBC progression and might be a potential new target for TNBC therapy. This study showed the effects of bisdemethoxycurcumin (BDMC) on GPR161 regulation, indicating that BDMC effectively inhibited GPR161 expression and downregulated GPR161-driven signaling. BDMC showed the potent inhibitory effects on TNBC proliferation through suppressing GPR161-mediated mammalian target of rapamycin (mTOR)/70 kDa ribosomal protein S6 kinase (p70S6K) activation. Besides, in this study, we discover the mechanism of GPR161-driven TNBC metastasis, linking to GPR161-mediated twist-related protein 1 (Twist1)/matrix metallopeptidase 9 (MMP9) contributing to the epithelial-mesenchymal transition (EMT). BDMC effectively repressed GPR161-mediated TNBC metastasis via inhibiting Twist1/MMP9-induced EMT. The three-dimensional invasion assay also showed that BDMC significantly inhibited TNBC invasion. The combination treatment of BDMC and rapamycin enhanced the inhibition of TNBC proliferation and metastasis through increasing the blockage of mTOR activation. Furthermore, this study also observed that BDMC activated the caspase 3/9 signaling pathway to induce TNBC apoptosis. Therefore, BDMC could be applicable to anticancer therapy, especially targeting on the GPR161-driven cancer type.
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Neoplasias de Mama Triplo Negativas , Apoptose , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Diarileptanoides , Transição Epitelial-Mesenquimal , Regulação Neoplásica da Expressão Gênica , Humanos , Receptores Acoplados a Proteínas G/genética , Transdução de Sinais , Sirolimo , Serina-Treonina Quinases TOR/genética , Serina-Treonina Quinases TOR/metabolismo , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/genéticaRESUMO
Snail is primarily known as a transcriptional repressor that induces epithelial-mesenchymal transition by suppressing adherent proteins. Emerging evidence suggests that Snail can act as an activator; however, the mechanism and biological significance are unclear. Here, we found that CREB-binding protein (CBP) is the critical factor in Snail-mediated target gene transactivation. CBP interacts with Snail and acetylates Snail at lysine 146 and lysine 187, which prevents the repressor complex formation. We further identified several Snail-activated targets, including TNF-α, which is also the upstream signal for Snail acetylation, and CCL2 and CCL5, which promote the recruitment of tumor-associated macrophages. Here, we present our results on the mechanism by which Snail induces target gene transactivation to remodel the tumor microenvironment.
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Macrófagos/patologia , Neoplasias/metabolismo , Fatores de Transcrição/metabolismo , Acetilação , Animais , Camundongos , Camundongos SCID , Dados de Sequência Molecular , Neoplasias/patologia , Prognóstico , Fatores de Transcrição da Família SnailRESUMO
Head and neck squamous cell carcinoma (HNSCC) is one of the leading causes of cancer deaths worldwide. In recent studies, a crucial link has been discovered between the acquisition of metastatic traits and tumour-initiating abilities in cancer cells during the epithelial-mesenchymal transition (EMT). Herein, we demonstrated that the ectopic expression of TWIST1, the EMT regulator, in HNSCC FaDu cells triggered EMT and resulted in the acquisition of a mesenchymal phenotype. Moreover, FaDu-pFLAG-TWIST1 cancer cell populations that were induced to EMT displayed an increased proportion of cells with the CD44 marker, which is associated with tumour initiation. Interestingly, we found that emodin treatment reduced the tumour-initiating abilities and inhibited cell migration and invasion in FaDu-pFLAG-TWIST1 cells. Emodin directly inhibited TWIST1 expression, upregulated E-cadherin mRNA and protein expression, and downregulated vimentin mRNA and protein expression. Moreover, we found that emodin inhibited TWIST1 binding to the E-cadherin promoter and repressed E-cadherin transcription activity. We also found that emodin inhibited TWIST1-induced EMT by inhibiting the ß-catenin and Akt pathways. More interestingly, emodin significantly inhibited TWIST1-induced invasion in vivo. Therefore, emodin might be applicable to anticancer therapy and could be a potential new therapeutic drug for HNSCC.
Assuntos
Carcinoma de Células Escamosas/tratamento farmacológico , Emodina/farmacologia , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Proteínas Nucleares/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteína 1 Relacionada a Twist/metabolismo , Animais , Western Blotting , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/metabolismo , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Movimento Celular/genética , Transição Epitelial-Mesenquimal/genética , Feminino , Células HEK293 , Neoplasias de Cabeça e Pescoço/genética , Neoplasias de Cabeça e Pescoço/metabolismo , Humanos , Masculino , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Microscopia Confocal , Pessoa de Meia-Idade , Proteínas Nucleares/genética , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Interferência de RNA , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/genética , Células Tumorais Cultivadas , Proteína 1 Relacionada a Twist/genética , Ensaios Antitumorais Modelo de Xenoenxerto , beta Catenina/genética , beta Catenina/metabolismoRESUMO
Visibility degradation caused by air pollution has become a serious environmental problem in megacities in Northeast Asia. In general, aerosol chemical compositions are measured by a conventional method of time integrated filter sampling for off-line analysis, which cannot represent temporal and spatial variations in the real atmosphere. The in situ air composition measuring equipment, OCEC carbon aerosol analyzer and a long-path visibility transmissometer-3 were used to collect hourly measurements of the soluble ions, organic/elemental carbon, and ambient visibility, respectively. During the observation, two types of weather conditions were identified: transport and stagnant. Because PM2.5 was identified as the predominant species of light extinction, the sources of PM2.5 were determined and investigated using a positive matrix factorization (PMF) analysis. The PMF outputs characterized the six main emission sources (marine/crustal aerosols, secondary nitrate, secondary sulfate, direct vehicle exhaust, coal/incinerator combustion, and local sewage emission) and reconstructed the PM2.5 mass concentrations of each pollutant source in two weather conditions. In addition, the light extinction (bext) was reconstructed using a multivariate linear regression analysis with hourly-reconstructed PM2.5 mass concentrations to determine the contributions of each source to bext. The primary results showed that the extinction coefficient was proportional to the PM2.5 with high value in stagnant weather conditions. The secondary sulfate was the most abundant source of bext contribution during the sampling period. In addition, the bext contributions of direct vehicle exhaust and coal/incinerator combustion significantly increased in the stagnant weather condition. According to the results of hourly measurements, this work further emphasized that the sources of direct vehicle exhaust and coal/incinerator combustion in PM2.5 were the important sources of visibility degradation in the stagnant weather conditions, which suggests that the pollutants derived from direct vehicle exhaust and coal/incinerator combustion should be controlled first to improve visibility in Taichung.
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Chromosomal instability (CIN) is widely considered a hallmark of cancer, but its precise roles in cancer stem cells (CSC) and malignant progression remain uncertain. BMI1 is a member of the Polycomb group of chromatin-modifier proteins that is essential for stem cell self-renewal. In human cancers, BMI1 overexpression drives stem-like properties associated with induction of epithelial-mesenchymal transition (EMT) that promotes invasion, metastasis, and poor prognosis. Here, we report that BMI1 mediates its diverse effects through upregulation of the mitotic kinase Aurora A, which is encoded by the AURKA gene. Two mechanisms were found to be responsible for BMI1-induced AURKA expression. First, BMI1 activated the Akt pathway, thereby upregulating AURKA expression through activation of the ß-catenin/TCF4 transcription factor complex. Second, BMI1 repressed miRNA let-7i through a Polycomb complex-dependent mechanism, thereby relieving AURKA expression from let-7i suppression. AURKA upregulation by BMI1 exerts several effects, including centrosomal amplification and aneuploidy, antiapoptosis, and cell-cycle progression through p53 degradation and EMT through stabilization of Snail. Inhibiting Aurora A kinase activity attenuated BMI1-induced tumor growth in vivo. In clinical specimens of head and neck cancer, we found that coamplification of BMI1 and AURKA correlated with poorer prognosis. Together, our results link CSCs, EMT, and CIN through the BMI1-AURKA axis and suggest therapeutic use from inhibiting Aurora A in head and neck cancers, which overexpress BMI1.
Assuntos
Instabilidade Cromossômica , Neoplasias de Cabeça e Pescoço/genética , Neoplasias de Cabeça e Pescoço/patologia , Complexo Repressor Polycomb 1/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Aurora Quinase A , Aurora Quinases , Linhagem Celular Tumoral , Progressão da Doença , Ativação Enzimática , Humanos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais , beta Catenina/metabolismoRESUMO
The epithelial-mesenchymal transition (EMT) is a key mechanism in both embryonic development and cancer metastasis. The EMT introduces stem-like properties to cancer cells. However, during somatic cell reprogramming, mesenchymal-epithelial transition (MET), the reverse process of EMT, is a crucial step toward pluripotency. Connective tissue growth factor (CTGF) is a multifunctional secreted protein that acts as either an oncoprotein or a tumor suppressor among different cancers. Here, we show that in head and neck squamous cell carcinoma (HNSCC), CTGF promotes the MET and reduces invasiveness. Moreover, we found that CTGF enhances the stem-like properties of HNSCC cells and increases the expression of multiple pluripotency genes. Mechanistic studies showed that CTGF induces c-Jun expression through αvß3 integrin and that c-Jun directly activates the transcription of the pluripotency genes NANOG, SOX2, and POU5F1. Knockdown of CTGF in TW2.6 cells was shown to reduce tumor formation and attenuate E-cadherin expression in xenotransplanted tumors. In HNSCC patient samples, CTGF expression was positively correlated with the levels of CDH1, NANOG, SOX2, and POU5F1. Coexpression of CTGF and the pluripotency genes was found to be associated with a worse prognosis. These findings are valuable in elucidating the interplay between epithelial plasticity and stem-like properties during cancer progression and provide useful information for developing a novel classification system and therapeutic strategies for HNSCC.
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Carcinoma de Células Escamosas/metabolismo , Fator de Crescimento do Tecido Conjuntivo/fisiologia , Transição Epitelial-Mesenquimal , Regulação Neoplásica da Expressão Gênica , Neoplasias de Cabeça e Pescoço/metabolismo , Ativação Transcricional , Animais , Sítios de Ligação , Carcinoma de Células Escamosas/mortalidade , Carcinoma de Células Escamosas/patologia , Movimento Celular , Intervalo Livre de Doença , Células HEK293 , Neoplasias de Cabeça e Pescoço/mortalidade , Neoplasias de Cabeça e Pescoço/patologia , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Humanos , Estimativa de Kaplan-Meier , Camundongos , Camundongos Nus , Proteína Homeobox Nanog , Invasividade Neoplásica , Transplante de Neoplasias , Células-Tronco Neoplásicas/metabolismo , Fator 3 de Transcrição de Octâmero/genética , Fator 3 de Transcrição de Octâmero/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Proteínas Proto-Oncogênicas c-jun/metabolismo , Fatores de Transcrição SOXB1/genética , Fatores de Transcrição SOXB1/metabolismo , Esferoides Celulares/metabolismo , TranscriptomaRESUMO
Substantial activation of the HGF/c-Met signaling pathway is involved in the progression of several types of cancers and associated with increased tumor invasion and metastatic potential. Underlying HGF-induced tumorigenesis, epithelial to mesenchymal transition (EMT) shows a positive correlation with progression in patients. We previously determined that osthole is a potent fatty acid synthase (FASN) inhibitor. FASN is implicated in cancer progression and may regulate lipid raft function. We therefore examined whether osthole could block HGF-induced tumorigenesis by disrupting lipid rafts. Here, we found that osthole could abrogate HGF-induced cell scattering, migration, and invasion in MCF-7 breast cancer cells. Osthole also effectively inhibited the HGF-induced decrease of E-cadherin and increase of vimentin via down-regulation of phosphorylated Akt and mTOR. Interestingly, osthole blocked HGF-induced c-Met phosphorylation and repressed the expression of total c-Met protein in MCF-7 cells. In addition, C75, a pharmacological inhibitor of FASN, repressed the expression of total c-Met protein in MCF-7 cells. Consistent with a role for FASN, loss of c-Met in cells treated with osthole was prevented by the exogenous addition of palmitate. Briefly, our result suggests a connection between FASN activity and c-Met protein expression and that osthole is a potential compound for breast cancer therapy by targeting the major pathway of HGF/c-Met-induced EMT.
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Neoplasias da Mama/patologia , Cumarínicos/farmacologia , Fator de Crescimento de Hepatócito/farmacologia , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-met/antagonistas & inibidores , Serina-Treonina Quinases TOR/antagonistas & inibidores , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Humanos , Invasividade Neoplásica , Fosforilação/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/fisiologia , Proteínas Proto-Oncogênicas c-met/fisiologia , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/fisiologiaRESUMO
While fatty acid synthase (FASN) has been shown to be expressed in many human solid tumors, FASN has also been identified in preneoplastic lesions. HER2, which has also been identified in preneoplastic breast lesions, has been shown to upregulate FASN expression. Osthole, an active constituent isolated from the fruit of Cnidium monnieri (L.) Cusson, a traditional Chinese medicine, was found to be effective in suppressing FASN expression in HER2-overexpressing breast cells. Osthole preferentially inhibited proliferation and induced apoptosis in HER2-overexpressing cancer cells. Moreover, osthole inhibited the phosphorylation of Akt and mTOR. The use of Akt-overexpression revealed that the modulation of Akt and mTOR was required for osthole-induced FASN suppression. Finally, we showed that osthole could enhance paclitaxel-induced cytotoxicity in HER2-overexpressing cancer cells. These results suggested that osthole has the potential to advance as chemopreventive or chemotherapeutic agent for cancers that overexpress HER2.