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1.
Int J Biol Macromol ; 261(Pt 1): 129670, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38280697

RESUMO

The oxidative microenvironment in fibrotic livers often diminishes the effectiveness of mesenchymal stem cells (MSCs)-based therapy. Recent research suggests that pharmacological pre-treatment could enhance the therapeutic performance of MSCs. In this study, we assessed the impact of Arctium lappa L. polysaccharides (ALP) on the biological properties of nasal ectomesenchymal stem cells (EMSCs) and investigated the augmenting effect of ALP pretreatment on EMSCs (ALP-EMSCs) for the treatment of liver fibrosis. ALP treatment demonstrated multiple biological impacts on EMSC functions regarding liver fibrosis: firstly, it maintained the stemness of the cells while boosting the EMSCs' paracrine effects; secondly, it increased the expression of anti-inflammatory and antioxidant factors; thirdly, it inhibited the activation of hepatic stellate cells (HSCs) and liver collagen build-up by modulating the Wnt/ß-catenin signaling pathways. Collectively, these effects helped to halt the progression of liver fibrosis. Therefore, the use of ALP-EMSCs presents an innovative and promising approach for treating hepatic fibrosis in clinical scenarios.


Assuntos
Arctium , Células-Tronco Mesenquimais , Humanos , beta Catenina/metabolismo , Via de Sinalização Wnt , Cirrose Hepática/tratamento farmacológico , Cirrose Hepática/metabolismo
2.
Water Sci Technol ; 88(1): 1-10, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37452529

RESUMO

The heterogeneous Fenton process is a strategy for overcoming the greatest shortcomings of traditional homogeneous Fenton, i.e. the high generation of ferric hydroxide sludge and effectivity in a limited pH range. In this study, we constructed a heterogeneous Fenton system with natural iron-bearing clay mineral (nontronite) and dimethoxyhydroquinone (DMHQ) to degrade lincomycin (LCM) without the addition of H2O2. The degradation mechanism was derived from the hydroxyl radicals (•OH) produced from the oxygenation of Fe(II) in nontronites, which was reduced by DMHQ. Acidic conditions and low concentrations of LCM were favourable for LCM degradation. When the solution pH increased from 3 to 7, the final LCM removal ratio decreased from 95 to 46%. However, LCM can still be degraded by 46% under neutral conditions and 20% at the LCM concentration of 500 µmol/L. The nontronite has good reusability, and the LCM degradation efficiency in the fourth cycle still exceeded 90% of the original efficiency. The degradation sites of LCM mainly occurred in the methyl thioether moiety and the aliphatic amine group on the pyrrolidine ring, with the final product of CO2. This research presents a new eco-friendly and cost-effective method for the heterogenous Fenton process without external H2O2.


Assuntos
Radical Hidroxila , Ferro , Ferro/química , Radical Hidroxila/química , Argila , Peróxido de Hidrogênio/química , Minerais/química , Oxirredução
3.
Oncogene ; 42(22): 1843-1856, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37081042

RESUMO

Oncogenic stress induces DNA damage repair (DDR) that permits escape from mitotic catastrophe and allows early precursor lesions during the evolution of cancer. SAMHD1, a dNTPase protecting cells from viral infections, has been recently found to participate in DNA damage repair process. However, its role in tumorigenesis remains largely unknown. Here, we show that SAMHD1 is up-regulated in early-stage human carcinoma tissues and cell lines under oxidative stress or genotoxic insults. We further demonstrate that de-ubiquitinating enzyme USP7 interacts with SAMHD1 and de-ubiquitinates it at lysine 421, thus stabilizing SAMHD1 protein expression for further interaction with CtIP for DDR, which promotes tumor cell survival under genotoxic stress. Furthermore, SAMHD1 levels positively correlates with USP7 in various human carcinomas, and is associated with an unfavorable survival outcome in patients who underwent chemotherapy. Moreover, USP7 inhibitor sensitizes tumor cells to chemotherapeutic agents by decreasing SAMHD1 in vitro and in vivo. These findings suggest that de-ubiquitination of SAMHD1 by USP7 promotes DDR to overcome oncogenic stress and affect chemotherapy sensitivity.


Assuntos
Dano ao DNA , Reparo do DNA , Humanos , Peptidase 7 Específica de Ubiquitina/genética , Proteína 1 com Domínio SAM e Domínio HD/genética , Ubiquitinação
4.
Quant Imaging Med Surg ; 13(3): 1927-1936, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36915340

RESUMO

Background: Early identification of severe acute pancreatitis (SAP) is key to reducing mortality and improving prognosis. We aimed to establish a radiomics model and nomogram for early prediction of acute pancreatitis (AP) severity based on contrast-enhanced computed tomography (CT) images. Methods: We retrospectively analyzed 215 patients with first-episode AP, including 141 in the training cohort (87 men and 54 women, mean age 51.37±16.09 years) and 74 in the test cohort (40 men and 34 women, mean age 55.49±17.83 years). Radiomics features were extracted from portal venous phase images based on pancreatic and peripancreatic regions. The light gradient boosting machine (LightGBM) algorithm was used for feature selection, a logistic regression (LR) model was established and trained by 10-fold cross-validation, and a nomogram was established based on the best features. The model's predictive performance was evaluated according to the area under the curve (AUC) of the receiver operating characteristic (ROC) curve, sensitivity, specificity, and accuracy. Results: A total of 13 optimal radiomics features were selected by LightGBM for LR model building. The AUC of the radiomics (LR) model was 0.992 [95% confidence interval (CI): 0.963-0.996] in the training cohort, 0.965 (95% CI: 0.924-0.981) in the validation cohort, and 0.894 (95% CI: 0.789-0.966) in the test cohort. The sensitivity was 0.862 (95% CI: 0.674-0.954), the specificity was 0.800 (95% CI: 0.649-0.899), and the accuracy was 0.824 (95% CI: 0.720-0.919). The nomogram based on the 13 radiomics features showed that SAP would be predicted when the total score was greater than 124. Conclusions: The radiomics model based on enhanced-CT images of pancreatic and peripancreatic regions performed well in the early prediction of AP severity. The nomogram based on selected radiomics features could provide a reference for AP clinical assessment.

5.
Hepatology ; 78(5): 1433-1447, 2023 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-36800849

RESUMO

BACKGROUND AND AIMS: Liver fibrosis is a leading indicator for increased mortality and long-term comorbidity in NASH. Activation of HSCs and excessive extracellular matrix production are the hallmarks of liver fibrogenesis. Tyrosine kinase receptor (TrkB) is a multifunctional receptor that participates in neurodegenerative disorders. However, paucity of literature is available about TrkB function in liver fibrosis. Herein, the regulatory network and therapeutic potential of TrkB were explored in the progression of hepatic fibrosis. METHODS AND RESULTS: The protein level of TrkB was decreased in mouse models of CDAHFD feeding or carbon tetrachloride-induced hepatic fibrosis. TrkB suppressed TGF-ß-stimulated proliferation and activation of HSCs in 3-dimensional liver spheroids and significantly repressed TGF-ß/SMAD signaling pathway either in HSCs or in hepatocytes. The cytokine, TGF-ß, boosted Nedd4 family interacting protein-1 (Ndfip1) expression, promoting the ubiquitination and degradation of TrkB through E3 ligase Nedd4-2. Moreover, carbon tetrachloride intoxication-induced hepatic fibrosis in mouse models was reduced by adeno-associated virus vector serotype 6 (AAV6)-mediated TrkB overexpression in HSCs. In addition, in murine models of CDAHFD feeding and Gubra-Amylin NASH (GAN), fibrogenesis was reduced by adeno-associated virus vector serotype 8 (AAV8)-mediated TrkB overexpression in hepatocytes. CONCLUSION: TGF-ß stimulated TrkB degradation through E3 ligase Nedd4-2 in HSCs. TrkB overexpression inhibited the activation of TGF-ß/SMAD signaling and alleviated the hepatic fibrosis both in vitro and in vivo . These findings demonstrate that TrkB could be a significant suppressor of hepatic fibrosis and confer a potential therapeutic target in hepatic fibrosis.


Assuntos
Cirrose Hepática , Hepatopatia Gordurosa não Alcoólica , Fator de Crescimento Transformador beta , Animais , Camundongos , Tetracloreto de Carbono , Células Estreladas do Fígado/metabolismo , Fígado/patologia , Cirrose Hepática/genética , Cirrose Hepática/metabolismo , Hepatopatia Gordurosa não Alcoólica/genética , Hepatopatia Gordurosa não Alcoólica/patologia , Receptores Proteína Tirosina Quinases , Transdução de Sinais , Fator de Crescimento Transformador beta/metabolismo , Fator de Crescimento Transformador beta1/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Proteínas Smad/genética , Proteínas Smad/metabolismo
6.
Cell Signal ; 100: 110466, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36100057

RESUMO

BACKGROUND AND AIM: Vascular endothelial cadherin (VE-cadherin) is an important element of adherens junctions (AJs) between endothelial cells. Its expression and proper distribution are critical for AJ formation and vascular integrity. Our previous studies have demonstrated that moesin phosphorylation mediated the hyper-permeability in endothelial monolayer and microvessels. However, the role of moesin and its phosphorylation in VE-cadherin expression and distribution is not clear. METHODS AND RESULTS: In vivo, expression of VE-cadherin was significantly reduced in retina and other various tissues in moesin knock out mice (Msn-/Y). In vitro, by regulating moesin expression with siRNA and adenovirus transfection, we verified that moesin has an effect on VE-cadherin expression in HUVECs, while transcription factor KLF4 may participate in this process. In addition, treatment of advanced glycation end products (AGEs) induced abnormal distribution of VE-cadherin in retinal microvessels from C57BL/6 wild type mice, and in vitro studies indicated that moesin Thr558 phosphorylation had a critical role in AGE-induced VE-cadherin internalization from cytomembrane to cytoplasm. Further investigation demonstrated that the inhibition of F-actin polymerization with cytochalasin D could abolish AGE- and Thr558 phosphor-moesin-mediated VE-cadherin internalization. CONCLUSION: This study suggests that moesin regulates VE-cadherin expression through KLF4 and the state of moesin phosphorylation at Thr558 affects the integrity of VE-cadherin-based AJs. Thr558 phosphor-moesin mediates AGE-induced VE-cadherin internalization through cytoskeleton reassembling.

7.
Front Oncol ; 11: 653061, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33996574

RESUMO

Pancreatic cancer is a common malignant tumor with a high incidence and mortality rate. The prognosis of patients with pancreatic cancer is considerably poor due to the lack of effective treatment in clinically. Despite numerous studies have revealed that baicalein, a natural product, is responsible for suppressing multiple cancer cells proliferation, motility and invasion. The mechanism by which baicalein restraining pancreatic cancer progression remains unclear. In this study, we firstly verified that baicalein plays a critical role in inhibiting pancreatic tumorigenesis in vitro and in vivo. Then we analyzed the alteration of microRNAs (miRNAs) expression levels in Panc-1 cells incubated with DMSO, 50 and 100 µM baicalein by High-Throughput sequencing. Intriguingly, we observed that 20 and 39 miRNAs were accordingly up- and down-regulated through comparing Panc-1 cells exposed to 100 µM baicalein with the control group. Quantitative PCR analysis confirmed that miR-139-3p was the most up-regulated miRNA after baicalein treatment, while miR-196b-5p was the most down-regulated miRNA. Further studies showed that miR-139-3p induced, miR-196b-5p inhibited the apoptosis of Panc-1 cells via targeting NOB1 and ING5 respectively. In conclusion, we demonstrated that baicalein is a potent inhibitor against pancreatic cancer by modulating the expression of miR-139-3p or miR-196b-5p.

8.
Front Oncol ; 11: 653902, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33928038

RESUMO

Hepatocellular carcinoma (HCC) as a main type of primary liver cancers has become one of the most deadly tumors because of its high morbidity and poor prognosis. Fucoidan is a family of natural, heparin-like sulfated polysaccharides extracted from brown algae. It is not only a widely used dietary supplement, but also participates in many biological activities, such as anti-oxidation, anti-inflammation and anti-tumor. However, the mechanism of fucoidan induced inhibition of HCC is elusive. In our study, we demonstrated that fucoidan contributes to inhibiting cell proliferation in vivo and in vitro, restraining cell motility and invasion and inducing cell cycle arrest and apoptosis. According to High-Throughput sequencing of long-non-coding RNA (lncRNA) in MHCC-97H cells treated with 0.5 mg/mL fucoidan, we found that 56 and 49 lncRNAs were correspondingly up- and down-regulated. LINC00261, which was related to the progression of tumor, was highly expressed in fucoidan treated MHCC-97H cells. Moreover, knocking down LINC00261 promoted cell proliferation by promoting the expression level of miR-522-3p, which further decreased the expression level of downstream SFRP2. Taken together, our results verified that fucoidan effectively inhibits the progression of HCC via causing lncRNA LINC00261 overexpression.

9.
Biomed Res Int ; 2021: 4628160, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35402605

RESUMO

Objectives: To report the long-term results of scleral buckling using 25-gauge chandelier illumination. Methods: The medical records of all patients presenting to Shanghai Tenth People's Hospital with simple rhegmatogenous retinal detachment (RRD) from June 2013 to Oct 2015 were retrospectively reviewed in this consecutive case series. All patients underwent preoperative and postoperative best corrected visual acuity (BCVA), B-ultrasound, fundus photography, and optical coherence tomography examination. Ultrasound biomicroscopy (UBM) was obtained postoperatively. Results: Ten patients (10 eyes) were included in the final analysis. Of 10 patients, the average age was 49.3 ± 18.9 years old, the average duration of RRD was 30.9 ± 53.3 days, and the mean follow-up period was 6.2 ± 0.9 years. There were nine eyes with myopia and four eyes with macular detachment. The primary anatomical success rate was 90%. Five eyes underwent 360-degree band with element surgery, and five eyes underwent element surgery alone. The average length of encircling band and element was 68.2 ± 1.3 mm and 10.5 ± 2.5 mm, respectively. There were no intraoperative or postoperative complications that occurred. The final BCVA was greater than or equal to 20/40 in nine eyes, of which four eyes achieved 20/20. UBM examination of the 25-gauge chandelier insertion site revealed no tissue proliferation. Conclusions: For simple rhegmatogenous retinal detachment treatment, 25-gauge chandelier illumination-assisted scleral buckling is a kind of effective and safe method.


Assuntos
Descolamento Retiniano , Recurvamento da Esclera , Adulto , Idoso , China , Humanos , Iluminação , Pessoa de Meia-Idade , Descolamento Retiniano/diagnóstico por imagem , Descolamento Retiniano/cirurgia , Estudos Retrospectivos , Recurvamento da Esclera/métodos , Resultado do Tratamento , Acuidade Visual , Vitrectomia
10.
Front Oncol ; 10: 632187, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33643923

RESUMO

As an important regulatory mechanism at the posttranscriptional level in metazoans, adenosine deaminase acting on RNA (ADAR)-induced A-to-I RNA editing modification of double-stranded RNA has been widely detected and reported. Editing may lead to non-synonymous amino acid mutations, RNA secondary structure alterations, pre-mRNA processing changes, and microRNA-mRNA redirection, thereby affecting multiple cellular processes and functions. In recent years, researchers have successfully developed several bioinformatics software tools and pipelines to identify RNA editing sites. However, there are still no widely accepted editing site standards due to the variety of parallel optimization and RNA high-seq protocols and programs. It is also challenging to identify RNA editing by normal protocols in tumor samples due to the high DNA mutation rate. Numerous RNA editing sites have been reported to be located in non-coding regions and can affect the biosynthesis of ncRNAs, including miRNAs and circular RNAs. Predicting the function of RNA editing sites located in non-coding regions and ncRNAs is significantly difficult. In this review, we aim to provide a better understanding of bioinformatics strategies for human cancer A-to-I RNA editing identification and briefly discuss recent advances in related areas, such as the oncogenic and tumor suppressive effects of RNA editing.

11.
Biochem Biophys Res Commun ; 515(1): 201-206, 2019 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-31146911

RESUMO

PURPOSE: Elevated levels of CXCL1 were observed in the cerebrospinal fluid of patients with early Alzheimer's disease, which may affect neural stem cells in the subventricular zone. We used APP/PS1 mice and neural stem cells to elucidate the role of CXCL1 in Alzheimer's disease. METHODS & RESULTS: We detected CXCL1 in cerebrospinal fluid (CSF), activated macrophages, and microglia suggesting that macrophages may contribute to elevated CXCL1 in the CSF of middle-aged APP/PS1 mice. Proliferation and differentiation of neural stem cells were further analyzed and the results suggested that CXCL1 promotes the proliferation of neural stem cells and inhibits their differentiation into astrocytes. In order to determine how CXCL1 exerts these effects, we analyzed intracellular reactive oxygen species, cell signaling, and performed in vivo recovery experiments. Our results suggest that CXCL1 promotes neural stem cell proliferation through a mechanism involving the production of reactive oxygen species and the PI3K/Akt pathway. CONCLUSION: In APP/PS1 mice, macrophage-derived CXCL1 can promote the proliferation of neural stem cells in the subventricular zone via the NOX2-ROS-PI3K/Akt pathway.


Assuntos
Proliferação de Células , Quimiocina CXCL1/metabolismo , Modelos Animais de Doenças , Células-Tronco Neurais/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Quimiocina CXCL1/líquido cefalorraquidiano , Humanos , Macrófagos/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Células-Tronco Neurais/citologia , Fosfatidilinositol 3-Quinases/metabolismo , Presenilina-1/genética , Presenilina-1/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais
12.
Med Microbiol Immunol ; 208(1): 59-68, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30171337

RESUMO

Escherichia coli K1 is the most common Gram-negative bacteria causing neonatal meningitis. Polymorphonuclear leukocyte (PMN) transmigration across the blood-brain barrier (BBB) is the hallmark of bacterial meningitis. Reportedly, the deletion of virulence factor cglD (E44:ΔcglD) from E44 is responsible for a less efficient PMN transendothelial migration ability. In the present study, we found that complementation of the cglD gene into E44:ΔcglD mutant strain might restore the PMN count and myeloperoxidase level in a neonatal mouse meningitis. Using human brain microvascular endothelial cells (HBMECs), the main model of the BBB in vitro, we found that E44:ΔcglD mutant strain induced a less efficient PMN adhesion to HBMECs and down-regulated chemokines CXCL1, CXCL6 and CXCL8 and adhesion molecule E-selectin, compared with the E44 strain. Complementation of cglD restored the PMN adhesion to HBMECs and the level of these proteins. E44:ΔcglD mutant strain also induced a less efficient NF-κB pathway activation in HBMECs and reduced the soluble p65 (sp65) level in the cerebral spinal fluid of newborn mice, compared with the E44 strain. Complementation of cglD restored the NF-κB pathway activation and increased the sp65 levels. This suggests that cglD in E44 contributes to NF-κB pathway activation in the brain endothelium to promote PMN adhesion to HBMECs and transendothelial migration. Our identified novel requirement of cglD for immune activation and subsequent PMN entry into the central nervous system suggests that therapies directed at neutralising this molecule will be beneficial in preventing bacterial meningitis progression.


Assuntos
Proteínas de Bactérias/metabolismo , Células Endoteliais/efeitos dos fármacos , Endotélio/efeitos dos fármacos , Escherichia coli/patogenicidade , Meningites Bacterianas/patologia , Neutrófilos/imunologia , Migração Transendotelial e Transepitelial , Fatores de Virulência/metabolismo , Animais , Animais Recém-Nascidos , Antígenos de Bactérias/análise , Adesão Celular , Células Cultivadas , Líquido Cefalorraquidiano/química , Modelos Animais de Doenças , Escherichia coli/classificação , Escherichia coli/isolamento & purificação , Feminino , Deleção de Genes , Teste de Complementação Genética , Humanos , Recém-Nascido , Masculino , Camundongos , Polissacarídeos Bacterianos/análise , Fator de Transcrição RelA/análise
13.
J Cereb Blood Flow Metab ; 38(5): 809-822, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-28430012

RESUMO

The level of granulocyte-macrophage colony-stimulating factor (GM-CSF) increases in some disorders such as vascular dementia, Alzheimer's disease, and multiple sclerosis. We previously reported that in Alzheimer's disease patients, a high level of GM-CSF in the brain parenchyma downregulated expression of ZO-1, a blood-brain barrier tight junction protein, and facilitated the infiltration of peripheral monocytes across the blood-brain barrier. However, the molecular mechanism underlying regulation of ZO-1 expression by GM-CSF is unclear. Herein, we found that the erythroblast transformation-specific (ETS) transcription factor ERG cooperated with the proto-oncogene protein c-MYC in regulation of ZO-1 transcription in brain microvascular endothelial cells (BMECs). The ERG expression was suppressed by miR-96 which was increased by GM-CSF through the phosphoinositide-3 kinase (PI3K)/Akt pathway. Inhibition of miR-96 prevented ZO-1 down-regulation induced by GM-CSF both in vitro and in vivo. Our results revealed the mechanism of ZO-1 expression reduced by GM-CSF, and provided a potential target, miR-96, which could block ZO-1 down-regulation caused by GM-CSF in BMECs.


Assuntos
Células Endoteliais/metabolismo , Regulação da Expressão Gênica/fisiologia , Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , MicroRNAs/metabolismo , Proteínas Oncogênicas/metabolismo , Regulador Transcricional ERG/metabolismo , Proteína da Zônula de Oclusão-1/biossíntese , Animais , Barreira Hematoencefálica/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL
14.
Int J Mol Sci ; 18(5)2017 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-28467355

RESUMO

The formation of brain vasculature is an essential step during central nervous system development. The molecular mechanism underlying brain angiogenesis remains incompletely understood. The role of Atg7, an autophagy-related protein, in brain angiogenesis was investigated in this study. We found that the microvessel density in mice brains with endothelial-specific knockout of Atg7 (Atg7 EKO) was significantly decreased compared to wild-type control. Consistently, in vitro angiogenesis assays showed that Atg7 knockdown impaired angiogenesis in brain microvascular endothelial cells. Further results indicated that knockdown of Atg7 reduced interleukin-6 (IL-6) expression in brain microvascular endothelial cells, which is mediated by NF-κB-dependent transcriptional control. Interestingly, exogenous IL-6 restored the impaired angiogenesis and reduced cell motility caused by Atg7 knockdown. These results demonstrated that Atg7 has proangiogenic activity in brain angiogenesis which is mediated by IL-6 production in a NF-κB-dependent manner.


Assuntos
Proteína 7 Relacionada à Autofagia/metabolismo , Encéfalo/irrigação sanguínea , Interleucina-6/metabolismo , NF-kappa B/metabolismo , Neovascularização Fisiológica/fisiologia , Análise de Variância , Animais , Proteína 7 Relacionada à Autofagia/genética , Movimento Celular/fisiologia , Células Cultivadas , Modelos Animais de Doenças , Células Endoteliais , Humanos , Camundongos , Camundongos Knockout , Microvasos/crescimento & desenvolvimento , Microvasos/metabolismo , Neovascularização Fisiológica/genética
15.
J Pineal Res ; 58(4): 429-38, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25752481

RESUMO

Melatonin induces apoptosis in many different cancer cell lines, including colorectal cancer. However, the precise mechanisms involved remain largely unresolved. In this study, we provide evidence to reveal a new mechanism by which melatonin induces apoptosis of colorectal cancer LoVo cells. Melatonin at pharmacological concentrations significantly suppressed cell proliferation and induced apoptosis in a dose-dependent manner. The observed apoptosis was accompanied by the melatonin-induced dephosphorylation and nuclear import of histone deacetylase 4 (HDAC4). Pretreatment with a HDAC4-specific siRNA effectively attenuated the melatonin-induced apoptosis, indicating that nuclear localization of HDAC4 is required for melatonin-induced apoptosis. Moreover, constitutively active Ca(2+) /calmodulin-dependent protein kinase II alpha (CaMKIIα) abrogated the melatonin-induced HDAC4 nuclear import and apoptosis of LoVo cells. Furthermore, melatonin decreased H3 acetylation on bcl-2 promoter, leading to a reduction of bcl-2 expression, whereas constitutively active CaMKIIα(T286D) or HDAC4-specific siRNA abrogated the effect of melatonin. In conclusion, the present study provides evidence that melatonin-induced apoptosis in colorectal cancer LoVo cells largely depends on the nuclear import of HDAC4 and subsequent H3 deacetylation via the inactivation of CaMKIIα.


Assuntos
Apoptose/efeitos dos fármacos , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Neoplasias Colorretais/metabolismo , Histona Desacetilases/metabolismo , Melatonina/farmacologia , Proteínas Repressoras/metabolismo , Acetilação/efeitos dos fármacos , Linhagem Celular Tumoral , Imunoprecipitação da Cromatina , Humanos
16.
Biomaterials ; 35(25): 6998-7007, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24857291

RESUMO

The development of diagnostic/therapeutic strategies against metastasis-related molecular targets is critical for improving the survival rate of cancer patients. Subtractive Cell-SELEX was performed using highly metastatic colorectal cancer (CRC) LoVo cells and non-metastatic HCT-8 cells as the target and negative cells, respectively, for the selection of metastatic-specific aptamers. This process generated seven aptamers that displayed highly specific binding to the target cells with Kds in the nanomolar range. Based on the distinct chemical/biological properties of their individual cell surface targets, the aptamers were separately functionalized: the receptor-targeting aptamer W14 was used as a carrier for doxorubicin, resulting in the specific delivery of the drug to the target cells and a significant reduction of its cytotoxicity to non-target cells, and the non-receptor-binding aptamer W3 was used as a molecular probe conjugated to quantum dots for the targeted imaging of metastatic cancer cell lines, spontaneous lung metastasis murine tissue, and metastatic CRC patient tissues. In addition, these aptamers can be used in combination due to their lack of detectable mutual-binding interference. The study demonstrates that a panel of aptamers that recognize distinct features of target molecules can be obtained through single Cell-SELEX selection, and the selected aptamers may be individually functionalized for specific applications and/or utilized in combination.


Assuntos
Aptâmeros de Nucleotídeos/química , Neoplasias Colorretais/metabolismo , Sistemas de Liberação de Medicamentos/métodos , Técnica de Seleção de Aptâmeros/métodos , Animais , Células CHO , Linhagem Celular Tumoral , Cricetulus , Diagnóstico por Imagem/métodos , Doxorrubicina/farmacologia , Feminino , Humanos , Camundongos , Camundongos Nus , Sondas Moleculares , Células NIH 3T3 , Pontos Quânticos
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