RESUMO
Neurodegenerative diseases (NDDs) pose a significant global health threat. In particular, Alzheimer disease, the most common type causing dementia, remains an incurable disease. Alzheimer disease is thought to be associated with an imbalance of reactive oxygen species (ROS) in neurons, and scientists considered ROS modulation as a promising strategy for novel remedies. In the study, human neural cell line SH-SY5Y was used in probing the effect of combining noninvasive high-frequency low-intensity pulsed electric field (H-LIPEF) and brain-derived neurotrophic factor (BDNF) in protection against hydrogen peroxide (H2O2)-induced neuron damage. Our result finds that the combination approach has intensified the neuroprotective effect significantly, perhaps due to H-LIPEF and BDNF synergistically increasing the expression level of the phosphorylated epidermal growth factor receptor (p-EGFR), which induces the survival-related mitogen-activated protein kinases (MAPK) proteins. The study confirmed the activation of extracellular signal-regulated kinase (ERK) and the downstream pro-survival and antioxidant proteins as the mechanism underlying neuron protection. These findings highlighted the potential of H-LIPEF combined with BDNF in the treatment of NDDs. Furthermore, BDNF-mimetic drugs combining with noninvasive H-LIPEF to patients is a promising approach worthy of further research. This points to strategies for selecting drugs to cooperate with electric fields in treating neurodegenerative disorders.
Assuntos
Doença de Alzheimer , Neuroblastoma , Fármacos Neuroprotetores , Humanos , Peróxido de Hidrogênio/farmacologia , Fator Neurotrófico Derivado do Encéfalo , Espécies Reativas de Oxigênio/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Linhagem Celular Tumoral , Fármacos Neuroprotetores/farmacologia , Sobrevivência Celular , ApoptoseRESUMO
To reduce side effects and enhance treatment efficacy, study on combination therapy for pancreatic cancer, a deadly cancer, has gained much attraction in recent years. In this study, we propose a novel triple treatment combining propolis and two physical stimuli-thermal cycling-hyperthermia (TC-HT) and low-intensity ultrasound (US). The study found that, after the triple treatment, the cell viability of a human cancer cell line PANC-1 decreased to a level 80% less than the control, without affecting the normal pancreatic cells. Another result was excessive accumulation of reactive oxygen species (ROS) after the triple treatment, leading to the amplification of apoptotic pathway through the MAPK family and mitochondrial dysfunction. This study, to the best of our knowledge, is the first attempt to combine TC-HT, US, and a natural compound in cancer treatment. The combination of TC-HT and US also promotes the anticancer effect of the heat-sensitive chemotherapy drug cisplatin on PANC-1 cells. It is expected that optimized parameters for different agents and different types of cancer will expand the methodology on oncological therapy in a safe manner.
Assuntos
Hipertermia Induzida , Neoplasias Primárias Múltiplas , Neoplasias Pancreáticas , Própole , Humanos , Própole/farmacologia , Hipertermia Induzida/métodos , Apoptose , Linhagem Celular Tumoral , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/metabolismo , Espécies Reativas de Oxigênio/metabolismoRESUMO
Despite continuation of some controversies, Alzheimer's disease (AD), the most common cause of dementia nowadays, has been widely believed to derive mainly from excessive ß-amyloid (Aß) aggregation, that would increase reactive oxygen species (ROS) and induce neuroinflammation, leading to neuron loss and cognitive impairment. Existing drugs on Aß have been ineffective or offer only temporary relief at best, due to blood-brain barrier or severe side effects. The study employed thermal cycling-hyperthermia (TC-HT) to ease the Aß-induced cognitive impairments and compared its effect with continuous hyperthermia (HT) in vivo. It established an AD mice model via intracerebroventricular (i.c.v.) injection of Aß25-35, proving that TC-HT is much more effective in alleviating its performance decline in Y-maze and novel object recognition (NOR) tests, in comparison with HT. In addition, TC-HT also exhibits a better performance in decreasing the hippocampal Aß and ß-secretase (BACE1) expressions as well as the neuroinflammation markers-ionized calcium-binding adapter molecule 1 (Iba-1) and glial fibrillary acidic protein (GFAP) levels. Furthermore, the study finds that TC-HT can elevate more protein expressions of insulin degrading enzyme (IDE) and antioxidative enzyme superoxide dismutase 2 (SOD2) than HT. In sum, the study proves the potential of TC-HT in AD treatment, which can be put into application with the use of focused ultrasound (FUS).
Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Hipertermia Induzida , Camundongos , Animais , Secretases da Proteína Precursora do Amiloide , Doenças Neuroinflamatórias , Camundongos Endogâmicos C57BL , Ácido Aspártico Endopeptidases , Doença de Alzheimer/terapia , Doença de Alzheimer/tratamento farmacológico , Disfunção Cognitiva/terapia , Disfunção Cognitiva/tratamento farmacológico , Peptídeos beta-Amiloides/toxicidade , Peptídeos beta-Amiloides/metabolismo , Modelos Animais de DoençasRESUMO
Middle East respiratory syndrome coronavirus (MERS-CoV) outbreaks have constituted a public health issue with drastic mortality higher than 34%, necessitating the development of an effective vaccine. During MERS-CoV infection, the trimeric spike protein on the viral envelope is primarily responsible for attachment to host cellular receptor, dipeptidyl peptidase 4 (DPP4). With the goal of generating a protein-based prophylactic, we designed a subunit vaccine comprising the recombinant S1 protein with a trimerization motif (S1-Fd) and examined its immunogenicity and protective immune responses in combination with various adjuvants. We found that sera from immunized wild-type and human DPP4 transgenic mice contained S1-specific antibodies that can neutralize MERS-CoV infection in susceptible cells. Vaccination with S1-Fd protein in combination with a saponin-based QS-21 adjuvant provided long-term humoral as well as cellular immunity in mice. Our findings highlight the significance of the trimeric S1 protein in the development of MERS-CoV vaccines and offer a suitable adjuvant, QS-21, to induce robust and prolonged memory T cell response.
Assuntos
Infecções por Coronavirus , Coronavírus da Síndrome Respiratória do Oriente Médio , Vacinas Virais , Animais , Camundongos , Humanos , Anticorpos Neutralizantes , Anticorpos Antivirais , Dipeptidil Peptidase 4 , Imunidade Celular , Camundongos Transgênicos , Adjuvantes Imunológicos , Proteínas Recombinantes , Vacinas de Subunidades Antigênicas , Glicoproteína da Espícula de CoronavírusRESUMO
White spot syndrome virus (WSSV) is a very large dsDNA virus. The accepted shape of the WSSV virion has been as ellipsoidal, with a tail-like extension. However, due to the scarcity of reliable references, the pathogenesis and morphogenesis of WSSV are not well understood. Here, we used transmission electron microscopy (TEM) and cryogenic electron microscopy (Cryo-EM) to address some knowledge gaps. We concluded that mature WSSV virions with a stout oval-like shape do not have tail-like extensions. Furthermore, there were two distinct ends in WSSV nucleocapsids: a portal cap and a closed base. A C14 symmetric structure of the WSSV nucleocapsid was also proposed, according to our Cryo-EM map. Immunoelectron microscopy (IEM) revealed that VP664 proteins, the main components of the 14 assembly units, form a ring-like architecture. Moreover, WSSV nucleocapsids were also observed to undergo unique helical dissociation. Based on these new results, we propose a novel morphogenetic pathway of WSSV.
Assuntos
Penaeidae , Vírus da Síndrome da Mancha Branca 1 , Animais , Vírus da Síndrome da Mancha Branca 1/genética , Nucleocapsídeo/química , Nucleocapsídeo/metabolismo , Vírion/metabolismo , Microscopia Eletrônica , Microscopia ImunoeletrônicaRESUMO
As the most common type of neurodegenerative diseases (NDDs), Alzheimer's disease (AD) is thought to be caused mainly by the excessive aggregation of ß-amyloid protein (Aß). However, a growing number of studies have found that reactive oxygen species (ROS) play a key role in the onset and progression of AD. The present study aimed to probe the neuroprotective effect of high-frequency low-intensity pulsed electric field (H-LIPEF) for SH-SY5Y cells against hydrogen peroxide (H2O2) and Aß-induced cytotoxicity. By looking in a systematic way into the frequency- and amplitude-dependent neuroprotective effect of pulsed electric field (PEF), the study finds that H-LIPEF at 200 Hz produces the optimal protective effect for SH-SY5Y cells. The underlying mechanisms were confirmed to be due to the activation of extracellular signal-regulated kinase (ERK) pathway and the downstream prosurvival and antioxidant proteins. Because the electric field can be modified to focus on specific area in a non-contact manner, the study suggests that H-LIPEF holds great potential for treating NDDs, whose effect can be further augmented with the administering of drugs or natural compounds at the same time.
Assuntos
Peptídeos beta-Amiloides/toxicidade , Eletricidade , Peróxido de Hidrogênio/toxicidade , Sistema de Sinalização das MAP Quinases , Neuroproteção , Morte Celular/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Flavonoides/farmacologia , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Fator 2 Relacionado a NF-E2/metabolismo , Neuroproteção/efeitos dos fármacos , Fosforilação/efeitos dos fármacos , Coloração e Rotulagem , Quinases Associadas a rho/metabolismoRESUMO
Neurodegenerative diseases (NDDs) are becoming a major threat to public health, according to the World Health Organization (WHO). The most common form of NDDs is Alzheimer's disease (AD), boasting 60-70% share. Although some debates still exist, excessive aggregation of ß-amyloid protein (Aß) and neurofibrillary tangles has been deemed one of the major causes for the pathogenesis of AD. A growing number of evidences from studies, however, have suggested that reactive oxygen species (ROS) also play a key role in the onset and progression of AD. Although scientists have had some understanding of the pathogenesis of AD, the disease still cannot be cured, with existing treatment only capable of providing a temporary relief at best, partly due to the obstacle of blood-brain barrier (BBB). The study was aimed to ascertain the neuroprotective effect of thermal cycle hyperthermia (TC-HT) against hydrogen peroxide (H2O2) and Aß-induced cytotoxicity in SH-SY5Y cells. Treating cells with this physical stimulation beforehand significantly improved the cell viability and decreased the ROS content. The underlying mechanisms may be due to the activation of Akt pathway and the downstream antioxidant and prosurvival proteins. The findings manifest significant potential of TC-HT in neuroprotection, via inhibition of oxidative stress and cell apoptosis. It is believed that coupled with the use of drugs or natural compounds, this methodology can be even more effective in treating NDDs.
Assuntos
Peptídeos beta-Amiloides/toxicidade , Peróxido de Hidrogênio/toxicidade , Hipertermia Induzida , Estresse Oxidativo/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Linhagem Celular Tumoral , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas de Choque Térmico/metabolismo , Humanos , Insulisina/metabolismo , Metaloproteinases da Matriz/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismoRESUMO
Most existing cancer treatments involve high-cost chemotherapy and radiotherapy, with major side effects, prompting effort to develop alternative treatment modalities. It was reported that the combination of thermal-cycling hyperthermia (TC-HT) and phenolic compound exhibited a moderate cytotoxic effect against human pancreatic cancer PANC-1 cells. In this study, we investigate the efficacy of triple combination in PANC-1 cancer cells by adopting low-intensity pulsed electric field (LIPEF) to couple with TC-HT and CGA (chlorogenic acid). The study finds that this triple combination can significantly impede the proliferation of PANC-1 cells, with only about 20% viable cells left after 24h, whereas being non-toxic to normal cells. The synergistic activity against the PANC-1 cells was achieved by inducing G2/M phase arrest and apoptosis, which were associated with up-regulation of p53 and coupled with increased expression of downstream proteins p21 and Bax. Further mechanism investigations revealed that the cytotoxic activity could be related to mitochondrial apoptosis, characterized by the reduced level of Bcl-2, mitochondrial dysfunction, and sequential activation of caspase-9 and PARP. Also, we found that the triple treatment led to the increase of intracellular reactive oxygen species (ROS) production. Notably, the triple treatment-induced cytotoxic effects and the elevated expression of p53 and p21 proteins as well as the increased Bax/Bcl-2 ratio, all could be alleviated by the ROS scavenger, N-acetyl-cysteine (NAC). These findings indicate that the combination of CGA, TC-HT, and LIPEF may be a promising modality for cancer treatment, as it can induce p53-dependent cell cycle arrest and apoptosis through accumulation of ROS in PANC-1 cells.
Assuntos
Antineoplásicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Ácido Clorogênico/farmacologia , Neoplasias Pancreáticas/terapia , Apoptose/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Radiação Eletromagnética , Humanos , Hipertermia Induzida/métodos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Neoplasias Pancreáticas/patologia , Espécies Reativas de Oxigênio/metabolismoRESUMO
Hyperthermia (HT) has shown potential in cancer therapy. In particular, it appears to sensitize cancer cells to chemotherapy. However, a major concern associated with HT is that the thermal dosage applied to the tumor cells may also harm the normal tissue cells. Besides, the drugs used in HT are conventional chemotherapy drugs, which may cause serious side effects. The present study demonstrated a novel methodology in HT therapy called thermal cycle (TC)HT. With this strategy, a therapeutic window with a maximum synergistic effect was created by combining TCHT with natural compounds, with minimal unwanted cell damage. The natural compound propolis was selected, and the synergistic anticancer effect of TCHT and propolis was investigated in pancreatic cancer cells. The present results demonstrated for the first time that TCHT could enhance the anticancer effect of propolis on PANC1 cancer cells through the mitochondriadependent apoptosis pathway and cell cycle arrest. Combined treatment greatly suppressed mitochondrial membrane potential, which is an important indicator of damaged and dysfunctional mitochondria. Furthermore, the cell cycleregulating protein cell division cycle protein 2 was downregulated upon combined treatment, which prevented cellular progression into mitosis. The present study offers the first report, to the best of our knowledge, on the combination of TCHT with a natural compound for pancreatic cancer treatment. It is anticipated that this methodology may be a starting point for more sophisticated cancer treatments and may thereby improve the quality of life of many patients with cancer.
Assuntos
Proteína Quinase CDC2/metabolismo , Hipertermia Induzida/métodos , Neoplasias Pancreáticas/metabolismo , Própole/farmacologia , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Terapia Combinada , Regulação para Baixo , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Neoplasias Pancreáticas/terapiaRESUMO
Hyperthermia (HT) has shown feasibility and potency as an anticancer therapy. Administration of HT in the chemotherapy has previously enhanced the cytotoxicity of drugs against pancreatic cancer. However, the drugs used when conducting these studies are substantially conventional chemotherapeutic agents that may cause unwanted side effects. Additionally, the thermal dosage in the treatment of cancer cells could also probably harm the healthy cells. The purpose of this work was to investigate the potential of the two natural polyphenolic compounds, epigallocatechin gallate (EGCG) and chlorogenic acid (CGA), as heat synergizers in the thermal treatment of the PANC-1 cells. Furthermore, we have introduced a unique strategy entitled the thermal cycling-hyperthermia (TC-HT) that is capable of providing a maximum synergy and minimal side effect with the anticancer compounds. Our results demonstrate that the combination of the TC-HT and the CGA or EGCG markedly exerts the anticancer effect against the PANC-1 cells, while none of the single treatment induced such changes. The synergistic activity was attributed to the cell cycle arrest at the G2/M phase and the induction of the ROS-dependent mitochondria-mediated apoptosis. These findings not only represent the first in vitro thermal synergistic study of natural compounds in the treatment of pancreatic cancer, but also highlight the potential of the TC-HT as an alternative strategy in thermal treatment.
Assuntos
Catequina/análogos & derivados , Sinergismo Farmacológico , Neoplasias Pancreáticas/terapia , Polifenóis/farmacologia , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Catequina/farmacologia , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Ácido Clorogênico , Terapia Combinada , Humanos , Hipertermia Induzida , Mitocôndrias/efeitos dos fármacos , Neoplasias Pancreáticas/patologiaRESUMO
With the expansion of the aged population, it is predicted that neurodegenerative diseases (NDDs) will become a major threat to public health worldwide. However, existing therapies can control the symptoms of the diseases at best, rather than offering a fundamental cure. As for the complex pathogenesis, clinical and preclinical researches have indicated that oxidative stress, a central role in neuronal degeneration, is a possible therapeutic target in the development of novel remedies. In this study, the motor neuron-like cell line NSC-34 was employed as an experimental model in probing the effects induced by the combination of non-invasive low intensity pulsed electric field (LIPEF) and fucoidan on the H2O2-induced neuron damage. It was found that single treatment of the LIPEF could protect the NSC-34 cells from oxidative stress, and the protective effect was enhanced by combining the LIPEF and fucoidan. Notably, it was observed that single treatment of the LIPEF obviously suppressed the H2O2-enhanced expression of ROCK protein and increased the phosphorylation of Akt in the H2O2-treated NSC-34 cells. Moreover, the LIPEF can be easily modified to concentrate on a specific area. Accordingly, this technique can be used as an advanced remedy for ROCK inhibition without the drawback of drug metabolism. Therefore, we suggest the LIPEF would be a promising strategy as a treatment for motor neurodegeneration and warrant further probe into its potential in treating other neuronal degenerations.
Assuntos
Terapia por Estimulação Elétrica , Neurônios Motores/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Polissacarídeos/farmacologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Quinases Associadas a rho/metabolismo , Animais , Morte Celular/efeitos dos fármacos , Linhagem Celular , Humanos , Camundongos , Neurônios Motores/patologia , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Doenças Neurodegenerativas/terapiaRESUMO
BACKGROUND: Pulsed electric field (PEF) has been considered as a cell permeability enhancing agent for cancer treatment. Nevertheless, application of PEF for conventional electrochemo-therapy is usually at high intensity, and contact or even invasive electrodes are typically used, which may cause unwanted side effects. In this study, a non-invasive way of applying low intensity, non-contact PEF was adopted to study its combination effect with herb, curcumin, against pancreatic cancer cells and the mechanism involved. METHODS: The pancreatic cancer PANC-1 cells were treated with curcumin and PEF alone or in combination, and MTT assay was used to determine the viability of PANC-1 cells. Apoptosis and uptake of curcumin were analyzed by microscopy and flow cytometry. Western blot was further performed to evaluate the expression of apoptotic proteins. RESULTS: Our results demonstrated that PEF synergized with curcumin to inhibit the proliferation of PANC-1 cells in a field strength- and dose-dependent manner and caused apoptotic death of PANC-1 cells. The apoptotic induction of combination treatment was characterized by an increase in Bax/Bcl-2 ratio, and cleavage of caspase-8, -9, and -3. Moreover, the increase of curcumin uptake via electro-endocytosis was clearly observed in the cells following the exposure of PEF. CONCLUSION: We show for the first time that a non-contact approach using low intensity electric field in a pulsed waveform could enhance the anticancer effect of low-dose curcumin on PANC-1 cells through triggering both extrinsic and intrinsic pathways. The findings highlight the potential of this alternative treatment, non-invasive electric field and curcumin, to increase therapeutic efficacy with minimum cytotoxicity and side effects, which may provide a new aspect of cancer treatment in combination of PEF and other anticancer agents.
RESUMO
Cancer is one of the most troublesome diseases and a leading cause of death worldwide. Recently, novel treatments have been continuously developed to improve the disadvantages of conventional therapies, such as prodigious expenses, unwanted side effects, and tumor recurrence. Here, we provide the first non-invasive treatment that has combined epigallocatechin gallate (EGCG), the most abundant catechin in green tea, with a low strength pulsed electric field (PEF) and a low energy ultrasound (US). It has been observed that the cell viability of human pancreatic cancer PANC-1 was decreased approximately to 20% of the control after this combination treatment for 72 h. Besides, the combined triple treatment significantly reduced the high tolerance of HepG2 cells to the EGCG-induced cytotoxicity and similarly exhibited compelling proliferation-inhibitory effects. We also found the combined triple treatment increased the intracellular reactive oxygen species (ROS) and acidic vesicles, and the EGCG-induced inhibition of Akt phosphorylation was dramatically intensified. In this study, the apoptosis inhibitor Z-VAD-FMK and the autophagy inhibitor 3-MA were, respectively, shown to attenuate the anticancer effects of the triple treatment. This indicates that the triple treatment-induced autophagy was switched from cytoprotective to cytotoxic, and hence, cooperatively caused cell death with the apoptosis. Since the EGCG is easily accessible from the green tea and mild for a long-term treatment, and the non-invasive physical stimulations could be modified to focus on a specific location, this combined triple treatment may serve as a promising strategy for anticancer therapy.
Assuntos
Catequina/análogos & derivados , Neoplasias/metabolismo , Tratamento por Radiofrequência Pulsada , Ondas Ultrassônicas , Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Caspases , Catequina/farmacologia , Catequina/uso terapêutico , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Terapia Combinada , Humanos , Neoplasias/patologia , Neoplasias/terapia , Tratamento por Radiofrequência Pulsada/métodos , Espécies Reativas de Oxigênio/metabolismo , Terapia por Ultrassom/métodosRESUMO
Static magnetic field (SMF) has shown some possibilities for cancer therapies. In particular, the combinational effect between SMF and anti-cancer drugs has drawn scientists' attentions in recent years. However, the underlying mechanism for the drug-specific synergistic effect is far from being understood. Besides, the drugs used are all conventional chemotherapy drugs, which may cause unpleasant side effects. In this study, our results demonstrate for the first time that SMF could enhance the anti-cancer effect of natural compound, capsaicin, on HepG2 cancer cells through the mitochondria-dependent apoptosis pathway. We found that the synergistic effect could be due to that SMF increased the binding efficiency of capsaicin for the TRPV1 channel. These findings may provide a support to develop an application of SMF for cancer therapy. The present study offers the first trial in combining SMF with natural compound on anti-cancer treatment, which provides additional insight into the interaction between SMF and anti-cancer drugs and opens the door for the development of new strategies in fighting cancer with minimum cytotoxicity and side effects.
Assuntos
Antineoplásicos/farmacologia , Capsaicina/farmacologia , Magnetismo , Canais de Cátion TRPV/metabolismo , Western Blotting , Cálcio/metabolismo , Proliferação de Células/efeitos dos fármacos , Células Hep G2 , Humanos , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Microscopia de Fluorescência , Proteína X Associada a bcl-2/metabolismoRESUMO
Traditional therapies for pancreatic cancer are usually expensive and likely to cause side effects, and most patients have the risk of recurrence and suffering pain. Here, we investigated combination treatment of epigallocatechin-3-gallate (EGCG) and non-invasive low strength pulsed electric field (PEF) on the human pancreatic cell line PANC-1. Cells were cultured in various concentrations of EGCG and exposed to trains of PEF. The results showed that the low strength PEF alone or single treatment with low concentration of EGCG did not obviously affect the cell proliferation and migration in PANC-1. However, the EGCG-induced inhibitions of cell viability and migration ability in PANC-1 were dramatically enhanced by the further exposure of low strength PEF (60 V/cm). In particular, the same combination treatment caused less inhibition of cell viability in non-malignant HEK293 cells. We also found the combination treatment significantly decreased the ratio of Bcl-2/Bax protein and increased caspase activity in PANC-1 cells, resulting in the promotion of apoptotic responses, evidenced by chromatin condensation. The findings of the present study reveal the synergistic reactions in the combination treatment may severely disturb mitochondria, enhance the intrinsic pathway transduction, and effectively induce apoptosis; moreover, the migration and invasion of PANC-1 cancer cells were also significantly suppressed. Since normal cells are less sensitive to this combination treatment, and the non-invasive PEF could be modified to focus on a specific location, this treatment may serve as a promising method for anti-cancer therapy.
Assuntos
Catequina/análogos & derivados , Eletricidade , Apoptose/efeitos dos fármacos , Catequina/farmacologia , Linhagem Celular Tumoral , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-bcl-2/metabolismoRESUMO
Helicobacter pylori (H. pylori) is a species of bacteria that can colonize the human stomach mucosa. It is closely associated with gastric diseases such as ulcer and inflammation. Recently, some H. pylori strains were found to express resistance to a family of antibiotics known as quinolones due to single-point mutations. Although traditional polymerase chain reaction (PCR) and molecular diagnostic-based approaches can be used to determine the presence and abundance of antibiotic-resistant H. pylori strains, such processes are relatively expensive, labor-intensive, and require bulky and costly equipment. This study therefore reports an advanced diagnostic assay performed on an integrated microfluidic system for rapid detection of antibiotic resistance in H. pylori. The assay features three components: (1) nucleic acid extraction by specific probe-conjugated magnetic beads, (2) amplification of the target deoxyribonucleic acid (DNA) fragments by using single-nucleotide-polymorphism polymerase chain reaction (SNP-PCR), and (3) optical detection of the PCR products. The device integrates several microfluidic components including micro-pumps, normally-closed micro-valves, and reaction chambers such that the entire diagnostic assay can be automatically executed on a single microfluidic system within one hour with detection limits of 10(0), 10(2), and 10(2) bacterial cells for H. pylori detection and two different SNP sites strains. Three PCR-based assays for determining presence of H. pylori infection and two DNA single-point mutation assays aimed at determining whether the infected strains were resistant to quinolone can be performed simultaneously on a single chip, suggesting that this microfluidic system could be a promising tool for rapid diagnosis of the presence of antibiotic-resistant H. pylori strains.
Assuntos
Técnicas Biossensoriais , DNA Bacteriano/genética , Resistência Microbiana a Medicamentos/genética , Infecções por Helicobacter/microbiologia , Helicobacter pylori/efeitos dos fármacos , DNA Bacteriano/isolamento & purificação , Infecções por Helicobacter/tratamento farmacológico , Helicobacter pylori/genética , Humanos , Microfluídica/métodos , Polimorfismo de Nucleotídeo Único , Quinolonas/uso terapêuticoRESUMO
A precise correlated color temperature (CCT) tuning method for light-emitting diodes (LEDs) has been developed and is demonstrated in this article. By combining LEDs and a liquid crystal (LC) cell, a light source with continuous CCT variation along a straight track on the chromaticity diagram is achieved. Moreover, the manner of CCT variation can be modulated by choosing appropriate LEDs and phosphors to yield a variation going from 3800 K to 6100 K with the track near the black-body locus. By adapting various developed LC technologies for diverse demands, the performance and applications of LEDs can be greatly improved.
RESUMO
The iron-containing hemoglobins (Hbs) are essential proteins to serve as oxygen transporters in the blood. Among various kinds of Hbs, the earthworm Hbs are the champions in carrying oxygen due to not only their large size but also the unusually high cooperativity of ligand binding. However, the cooperative oxygen binding mechanisms are still mostly unknown. Here we report the cryo-electron microscopy structure of Lumbricus terrestris Hb in its native, oxygenated state at 9.1 Å resolution, showing remarkable differences from the carbon monoxide-binding X-ray structure. Our structural analysis first indicates that the cooperative ligand binding of L. terrestris Hb requires tertiary and quaternary transitions in the heme pocket and a global subunit movement facilitated by intra-ring and inter-ring contacts. Moreover, the additional sinusoidal bracelet provides the confirmation for the long-standing debate about the additional electron densities absent in the X-ray crystal structure.
Assuntos
Hemoglobinas/metabolismo , Oligoquetos/metabolismo , Oxigênio/metabolismo , Animais , Sítios de Ligação , Dióxido de Carbono/química , Dióxido de Carbono/metabolismo , Microscopia Crioeletrônica , Cristalografia por Raios X , Heme/metabolismo , Hemoglobinas/química , Oxigênio/química , Ligação Proteica , Estrutura Terciária de ProteínaRESUMO
To overcome the problem of high driving voltage and low contrast ratio in the switchable scattering device of conventional liquid-crystal (LC) physical gel, a new type of supramolecular LC physical gel has been developed and fabricated through the fibrous self-assembly of the polyfluorene-based π-conjugated polymer, poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT), in nematic LC mixture E7. It was found that the rubbed interface between the LC molecules and polyimide layer can induce the LC physical gels to demonstrate fantastic light scattering characteristic. The gels with oriented self-assembled supramolecular structures exhibiting significant anisotropic light scattering in the main-chain direction of the F8BT molecules under an extremely low driving voltage (ca. 2.7 V) are reported for the first time. In addition, the contrast ratio can be reached exceeding 1000. In contrast to conventional LC physical gels, the large reduction of driving voltages of the supramolecular gel provides great possibility for application in various electro-optical devices such as tunable polarizers, transflective displays, and polarized light modulators.
RESUMO
In this paper, doping liquid materials to enhance the electro-optical (EO) properties of twisted nematic liquid crystals (NLCs) was presented. Two aromatic hydrocarbon (AH) liquids, toluene and 1-methylnaphthalene, were chosen as dopants in order to lower the driving voltage and response time of the NLCs. A 18% decrease in driving voltage and response time was achieved by doping 10 wt% toluene into NLCs. The main reason of this phenomenon is due to a large amount of reduction in the rotational viscosity of AH liquids doped NLCs. This method provides an easy and potential choice for applications in various LC display systems.