RESUMO
Acute promyelocytic leukemia (APL), a distinctive subtype of acute myeloid leukemia (AML), is characterized by the t(15; 17) translocation forming the PML-RARα fusion protein. Recent studies have revealed a crucial role of retinoid X receptor α (RXRα) in PML-RARα's tumorigenesis. This necessitates the development of dual RARα and RXRα targeting compounds for treating APL. Here, we developed a pair of brominated retinoid isomers, 5a and 5b, exhibiting RARα agonistic selectivity among the RAR subtypes and RXRα partial agonistic activities. In the treatment of APL cells, low doses (RARα activation range) of 5a and 5b degrade PML-RARα and strongly induce differentiation, while higher doses (RXRα activation range) induce G2/M arrest and apoptosis in both all-trans retinoic acid (ATRA)-sensitive and resistant cells. We replaced the bromine in 5a with chlorine or iodine to obtain compounds 7 or 8a. Interestingly, the chlorinated compound 7 tends to activate RXRα and induce G2/M arrest and apoptosis, while the iodinated compound 8a tends to activate RARα and induce differentiation. Together, our work underscores several advantages and characteristics of halogens in the rational design of RARα and RXRα ligands, offering three promising drug candidates for treating both ATRA-sensitive and resistant APL.
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Blood amino acid levels are maintained in a narrow physiological range. The pancreatic α cells have emerged as the primary aminoacidemia regulator through glucagon secretion to promote hepatic amino acid catabolism. Interruption of glucagon signaling disrupts the liver-α cells axis leading to hyperaminoacidemia, which triggers a compensatory rise in glucagon secretion and α cell hyperplasia. The mechanisms of hyperaminoacidemia-induced α cell hyperplasia remain incompletely understood. Using a mouse α cell line and in vivo studies in zebrafish and mice, we found that hyperaminoacidemia-induced α cell hyperplasia requires ErbB3 signaling. In addition to mechanistic target of rapamycin complex 1, another ErbB3 downstream effector signal transducer and activator of transcription 3 also plays a role in α cell hyperplasia. Mechanistically, ErbB3 may partner with ErbB2 to stimulate cyclin D2 and suppress p27 via mechanistic target of rapamycin complex 1 and signal transducer and activator of transcription 3. Our study identifies ErbB3 as a new regulator for hyperaminoacidemia-induced α cell proliferation and a critical component of the liver-α cells axis that regulates aminoacidemia.
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The dysfunction of matriptase, a membrane-anchored protease, is highly related to the progression of skin and breast cancers. Epidermal growth factor (EGF)-induced matriptase activation and cancer invasion are known but with obscure mechanisms. Here, we demonstrate a vesicular-trafficking-mediated interplay between matriptase and EGF signaling in cancer promotion. We found that EGF induces matriptase to undergo endocytosis together with the EGF receptor, followed by acid-induced activation in endosomes. Activated matriptase is then secreted extracellularly on exosomes to catalyze hepatocyte growth factor precursor (pro-HGF) cleavage, resulting in autocrine HGF/c-Met signaling. Matriptase-induced HGF/c-Met signaling represents the second signal wave of EGF, which promotes cancer cell scattering, migration, and invasion. These findings demonstrate a role of vesicular trafficking in efficient activation and secretion of membrane matriptase and a reciprocal regulation of matriptase and EGF signaling in cancer promotion, providing insights into the physiological functions of vesicular trafficking and the molecular pathological mechanisms of skin and breast cancers.
Assuntos
Neoplasias da Mama , Invasividade Neoplásica , Serina Endopeptidases , Transdução de Sinais , Animais , Feminino , Humanos , Camundongos , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Movimento Celular , Endocitose , Endossomos/metabolismo , Fator de Crescimento Epidérmico/metabolismo , Receptores ErbB/metabolismo , Exossomos/metabolismo , Fator de Crescimento de Hepatócito/metabolismo , Precursores de Proteínas , Proteínas Proto-Oncogênicas c-met/metabolismo , Serina Endopeptidases/metabolismo , Neoplasias Cutâneas/patologia , Neoplasias Cutâneas/metabolismoRESUMO
The application of oncolytic peptides has become a powerful approach to induce complete and long-lasting remission in multiple types of carcinomas, as affirmed by the appearance of tumor-associated antigens and adenosine triphosphate (ATP) in large quantities, which jumpstarts the cancer-immunity cycle. However, the ATP breakdown product adenosine is a significant contributor to forming the immunosuppressive tumor microenvironment, which substantially weakens peptide-driven oncolytic immunotherapy. In this study, a lipid-coated micelle (CA@TLM) loaded with a stapled oncolytic peptide (PalAno) and an adenosine 2A receptor (A2AR) inhibitor (CPI-444) is devised to enact tumor-targeted oncolytic immunotherapy and to overcome adenosine-mediated immune suppression simultaneously. The CA@TLM micelle accumulates in tumors with high efficiency, and the acidic tumor microenvironment prompts the rapid release of PalAno and CPI-444. Subsequently, PalAno induces swift membrane lysis of tumor cells and the release of antigenic materials. Meanwhile, CPI-444 blocks the activation of the immunosuppressive adenosine-A2AR signaling pathway. This combined approach exhibits pronounced synergy at stalling tumor growth and metastasis in animal models for triple-negative breast cancer and melanoma, providing a novel strategy for enhanced oncolytic immunotherapy.
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This study constructed a nano-drug delivery system, A3@GMH, by co-delivering the stapled anoplin peptide(Ano-3, A3) with the light-harvesting material graphene oxide(GO), and evaluated its oncolytic immunotherapy effect on triple-negative breast cancer(TNBC). A3@GMH was prepared using an emulsion template method and its physicochemical properties were characterized. The in vivo and in vitro photothermal conversion abilities of A3@GMH were investigated using an infrared thermal imager. The oncoly-tic activity of A3@GMH against TNBC 4T1 cells was evaluated through cell counting kit-8(CCK-8), lactate dehydrogenase(LDH) release, live/dead cell staining, and super-resolution microscopy. The targeting properties of A3@GMH on 4T1 cells were assessed using a high-content imaging system and flow cytometry. In vitro and in vivo studies were conducted to investigate the antitumor mechanism of A3@GMH in combination with photothermal therapy(PTT) through inducing immunogenic cell death(ICD) in 4T1 cells. The results showed that the prepared A3@GMH exhibited distinct mesoporous and coated structures with an average particle size of(308.9±7.5) nm and a surface potential of(-6.79±0.58) mV. The encapsulation efficiency and drug loading of A3 were 23.9%±0.6% and 20.5%±0.5%, respectively. A3@GMH demonstrated excellent photothermal conversion ability and biological safety. A3@GMH actively mediated oncolytic features such as 4T1 cell lysis and LDH release, as well as ICD effects, and showed enhanced in vitro antitumor activity when combined with PTT. In vivo, A3@GMH efficiently induced ICD effects with two rounds of PTT, activated the host's antitumor immune response, and effectively suppressed tumor growth in 4T1 tumor-bearing mice, achieving an 88.9% tumor inhibition rate with no apparent toxic side effects. This study suggests that the combination of stapled anoplin peptide and PTT significantly enhances the oncolytic immunotherapy for TNBC and provides a basis for the innovative application of anti-tumor peptides derived from TCM in TNBC treatment.
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Nanopartículas , Neoplasias de Mama Triplo Negativas , Humanos , Animais , Camundongos , Terapia Fototérmica , Neoplasias de Mama Triplo Negativas/terapia , Neoplasias de Mama Triplo Negativas/patologia , Peptídeos Catiônicos Antimicrobianos , Imunoterapia/métodos , Linhagem Celular Tumoral , Fototerapia/métodos , Nanopartículas/químicaRESUMO
BACKGROUND: The maturation of microRNAs (miRNAs) successively undergoes Drosha, Dicer, and Argonaute -mediated processing, however, the intricate regulations of the individual miRNA maturation are largely unknown. Retinoid x receptor alpha (RXRα) belongs to nuclear receptors that regulate gene transcription by binding to DNA elements, however, whether RXRα binds to miRNAs to exert physiological functions is not known. RESULTS: In this work, we found that RXRα directly binds to the precursor of miR-103 (pre-miR-103a-2) via its DNA-binding domain with a preferred binding sequence of AGGUCA. The binding of RXRα inhibits the processing of miR-103 maturation from pre-miR-103a-2. Mechanistically, RXRα prevents the nuclear export of pre-miR-103a-2 for further processing by inhibiting the association of exportin-5 with pre-miR-103a-2. Pathophysiologically, the negative effect of RXRα on miR-103 maturation correlates to the positive effects of RXRα on the expression of Dicer, a target of miR-103, and on the inhibition of breast cancer. CONCLUSIONS: Our findings unravel an unexpected role of transcription factor RXRα in specific miRNA maturation at post-transcriptional level through pre-miRNA binding, and present a mechanistic insight regarding RXRα role in breast cancer progression.
Assuntos
MicroRNAs , Receptores Citoplasmáticos e Nucleares , Fatores de Transcrição , Proteínas Argonautas , MicroRNAs/genéticaRESUMO
Prostate adenocarcinoma (PRAD) is the most frequent malignancy, and is the second leading cause of death due to cancer in men. Thus, new prognostic biomarkers and drug targets for PRAD are urgently needed. As we know, nuclear receptor Nur77 is important in cancer development and changes in the tumor microenvironment; whereas, the function of Nur77 in PRAD remains to be elucidated. The TCGA database was used to explore the Nur77 expression and its role in the prognosis of PRAD. It was shown that Nur77 was down regulated in PRAD, and low Nur77 expression was correlated with advanced clinical pathologic characteristics (high grade, histological type, age) and poor prognosis. Furthermore, key genes screening was examined by univariate Cox analysis and Kaplan-Meier survival. Additionally, Nur77 was closely related to immune infiltration and some anti-tumor immune functions. The differentially expressed genes (DEGs) were presented by protein-protein interaction (PPI) network analysis. Therefore, the expression level of Nur77 might help predict the survival of PRAD cases, which presents a new insight and a new target for the treatment of PRAD. In vitro experiments verified that natural product malayoside targeting Nur77 exhibited significant therapeutic effects on PRAD and largely induced cell apoptosis by up-regulating the expression of Nur77 and its mitochondrial localization. Taken together, Nur77 is a prognostic biomarker for patients with PRAD, which may refresh the profound understanding of PRAD individualized treatment.
Assuntos
Adenocarcinoma , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares , Neoplasias da Próstata , Humanos , Masculino , Adenocarcinoma/tratamento farmacológico , Adenocarcinoma/genética , Biomarcadores , Prognóstico , Próstata , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/genética , Microambiente Tumoral/genética , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/genéticaRESUMO
Six new citreoviridins (citreoviridins J-O, 1-6) and twenty-two known compounds (7-28) were isolated from the deep-sea-derived Penicillium citreonigrum MCCC 3A00169. The structures of the new compounds were determined by spectroscopic methods, including the HRESIMS, NMR, ECD calculations, and dimolybdenum tetraacetate-induced CD (ICD) experiments. Citreoviridins J-O (1-6) are diastereomers of 6,7-epoxycitreoviridin with different chiral centers at C-2-C-7. Pyrenocine A (7), terrein (14), and citreoviridin (20) significantly induced apoptosis for HeLa cells with IC50 values of 5.4 µM, 11.3 µM, and 0.7 µM, respectively. To be specific, pyrenocine A could induce S phase arrest, while terrein and citreoviridin could obviously induce G0-G1 phase arrest. Citreoviridin could inhibit mTOR activity in HeLa cells.
Assuntos
Penicillium , Humanos , Células HeLa , Linhagem Celular Tumoral , Penicillium/química , Espectroscopia de Ressonância Magnética/métodos , Estrutura MolecularRESUMO
The glucagon receptor (GCGR) is a potential target for diabetes therapy. Several emerging GCGR antagonism-based therapies are under preclinical and clinical development. However, GCGR antagonism, as well as genetically engineered GCGR deficiency in animal models, are accompanied by α-cell hyperplasia and hyperglucagonemia, which may limit the application of GCGR antagonism. To better understand the physiological changes in α cells following GCGR disruption, we performed single cell sequencing of α cells isolated from control and gcgr-/- (glucagon receptor deficient) zebrafish. Interestingly, beyond the α-cell hyperplasia, we also found that the expression of gcga, gcgb, pnoca, and several glucagon-regulatory transcription factors were dramatically increased in one cluster of gcgr-/- α cells. We further confirmed that glucagon mRNA was upregulated in gcgr-/- animals by in situ hybridization and that glucagon promoter activity was increased in gcgr-/-;Tg(gcga:GFP) reporter zebrafish. We also demonstrated that gcgr-/- α cells had increased glucagon protein levels and increased granules after GCGR disruption. Intriguingly, the increased mRNA and protein levels could be suppressed by treatment with high-level glucose or knockdown of the pnoca gene. In conclusion, these data demonstrated that GCGR deficiency not only induced α-cell hyperplasia but also increased glucagon expression in α cells, findings which provide more information about physiological changes in α-cells when the GCGR is disrupted.
Assuntos
Glucagon , Receptores de Glucagon , Animais , Receptores de Glucagon/genética , Receptores de Glucagon/metabolismo , Peixe-Zebra/genética , Peixe-Zebra/metabolismo , Hiperplasia , RNA MensageiroRESUMO
Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease that may progress to nonalcoholic steatohepatitis (NASH), hepatic tissue fibrosis, liver cirrhosis, and hepatocellular carcinoma. In this study, we investigated the effects of Pien Tze Huang (PTH), a well-known traditional Chinese herbal formula with liver protective effect, in methionine-choline deficient diet (MCD)- and high-fat diet (HFD)-induced NASH mouse models. Our results showed that PTH could exert hepatoprotective effects by improving liver weight and steatosis and reducing the fibrosis and serum levels of alanine transaminase (ALT) and aspartate transaminase (AST) in both animal models. The effects of PTH was accompanied with the reduction of infiltrated macrophages, the inhibition of the expression of cytokines, and the induction of adiponectin expression. Mechanistically, we found that PTH could inhibit the activation of proinflammatory transcription factor nuclear factor-κB (NF-κB) by preventing the degradation of inhibitor of κBα (IκBα). These results demonstrate that PTH can improve NAFLD largely due to its suppression of the NF-κB inflammatory pathway.
Assuntos
Medicamentos de Ervas Chinesas , Hepatopatia Gordurosa não Alcoólica , Animais , Anti-Inflamatórios/metabolismo , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Modelos Animais de Doenças , Medicamentos de Ervas Chinesas/metabolismo , Medicamentos de Ervas Chinesas/farmacologia , Medicamentos de Ervas Chinesas/uso terapêutico , Fibrose , Fígado , Cirrose Hepática/metabolismo , Metionina/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , NF-kappa B/metabolismo , Hepatopatia Gordurosa não Alcoólica/metabolismoRESUMO
3-chyomotrypsin like protease (3CLpro) has been considered as a promising target for developing anti-SARS-CoV-2 drugs. Herein, about 6000 compounds were analyzed by high-throughput screening using enzyme activity model, and Merbromin, an antibacterial agent, was identified as a potent inhibitor of 3CLpro. Merbromin strongly inhibited the proteolytic activity of 3CLpro but not the other three proteases Proteinase K, Trypsin and Papain. Michaelis-Menten kinetic analysis showed that Merbromin was a mixed-type inhibitor of 3CLpro, due to its ability of increasing the KM and decreasing the Kcat of 3CLpro. The binding assays and molecular docking suggested that 3CLpro possessed two binding sites for Merbromin. Consistently, Merbromin showed a weak binding to the other three proteases. Together, these findings demonstrated that Merbromin is a selective inhibitor of 3CLpro and provided a scaffold to design effective inhibitors of SARS-CoV-2.
Assuntos
Proteases 3C de Coronavírus/antagonistas & inibidores , Merbromina/farmacologia , Simulação de Acoplamento Molecular , Inibidores de Proteases/farmacologia , SARS-CoV-2/efeitos dos fármacos , Sítios de Ligação , COVID-19/prevenção & controle , COVID-19/virologia , Proteases 3C de Coronavírus/química , Proteases 3C de Coronavírus/metabolismo , Ensaios de Triagem em Larga Escala/métodos , Humanos , Cinética , Merbromina/química , Merbromina/metabolismo , Modelos Moleculares , Estrutura Molecular , Inibidores de Proteases/química , Inibidores de Proteases/metabolismo , Ligação Proteica , Domínios Proteicos , SARS-CoV-2/enzimologia , SARS-CoV-2/fisiologia , Ressonância de Plasmônio de Superfície/métodosRESUMO
This study aimed to explore which age group out of the patients in quarantine wards with novel coronavirus pneumonia is the most susceptible to anxiety. The data of 32 Covid-19 patients isolated in the quarantine wards of the second Infectious Diseases Department of Baoding Hospital and 71 Covid-19 patients in Tangshan City Infectious Disease Hospital from January 24th to March 5th, 2020, a total of 103 patients, were analyzed. Among these patients, 97 isolated patients were scored with a self-rating anxiety scale (SAS) score seven days after quarantine, and the correlation between age and score was analyzed. These 97 isolated patients were then divided into three groups according to age: group A (up to 35 years old), group B (36-60 years), and group C (over 60 years). One-way analysis of variance was used to compare the scores among groups. The Q-test was used for pairwise comparison.P < 0.05 was considered statistically significant.There was a negative correlation between age and SAS score in isolated Covid-19 patients, and the differences in the score among groups were statistically significant. Patients under 35 years old were more prone to anxiety when they were isolated for seven days. Isolated patients aged up to 35 years old need more attention from quarantine medical staff, communication should be strengthened, and psychological intervention from psychotherapists should be given if necessary.
Assuntos
COVID-19 , Quarentena , Adulto , Idoso , Ansiedade/epidemiologia , Ansiedade/psicologia , COVID-19/epidemiologia , Humanos , Quarentena/psicologia , SARS-CoV-2 , Inquéritos e QuestionáriosRESUMO
Liquid-liquid phase separation promotes the formation of membraneless condensates that mediate diverse cellular functions, including autophagy of misfolded proteins. However, how phase separation participates in autophagy of dysfunctional mitochondria (mitophagy) remains obscure. We previously discovered that nuclear receptor Nur77 (also called TR3, NGFI-B, or NR4A1) translocates from the nucleus to mitochondria to mediate celastrol-induced mitophagy through interaction with p62/SQSTM1. Here, we show that the ubiquitinated mitochondrial Nur77 forms membraneless condensates capable of sequestrating damaged mitochondria by interacting with the UBA domain of p62/SQSTM1. However, tethering clustered mitochondria to the autophagy machinery requires an additional interaction mediated by the N-terminal intrinsically disordered region (IDR) of Nur77 and the N-terminal PB1 domain of p62/SQSTM1, which confers Nur77-p62/SQSTM1 condensates with the magnitude and liquidity. Our results demonstrate how composite multivalent interaction between Nur77 and p62/SQSTM1 coordinates to sequester damaged mitochondria and to connect targeted cargo mitochondria for autophagy, providing mechanistic insight into mitophagy.
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Mitocôndrias/efeitos dos fármacos , Mitofagia/efeitos dos fármacos , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/genética , Triterpenos Pentacíclicos/farmacologia , Proteína Sequestossoma-1/genética , Animais , Complexo IV da Cadeia de Transporte de Elétrons , Feminino , Regulação da Expressão Gênica , Genes Reporter , Proteínas de Fluorescência Verde , Células HeLa , Humanos , Proteínas Luminescentes , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias/genética , Mitocôndrias/metabolismo , Mitofagia/genética , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Ligação Proteica , Transporte Proteico , Proteínas Recombinantes de Fusão , Reologia , Proteína Sequestossoma-1/metabolismo , Fator de Necrose Tumoral alfa/farmacologia , Proteína Vermelha FluorescenteRESUMO
Liposome-based immunoassay (LIA) is an attractive protocol for amplifying the detection signals because of the excellent ability of liposomes to encapsulate signal marker compounds. The antigen-binding activity of the conjugated antibodies on the liposomal surface is crucial for the specificity and sensitivity of LIA. We present here a general platform to ensure that antibodies can conjugate onto the surface of liposomes in a site-specific and oriented manner. A His-handle-modified antibody with Fc region-specific and covalent conjugation was first fabricated using a photoactivatable ZBpa-His tag that was engineered using the aminoacyl-tRNA synthetase/suppressor tRNA technique. Based on the high affinity between the His tag and divalent metal ions, the novel His-modified antibody was oriented onto the surface of nickel ion-modified liposomes encapsulating horseradish peroxidase. With the prostate-specific antigen as a model, the detection efficiency of the new immunoliposomes was evaluated by chemiluminescence immunoassay. The immunoliposomes exhibited a limit of detection of 0.2 pg mL-1, which was a six time improvement compared with that of the chemical-coupled antibody-liposome conjugates. Thus, the proposed immunoliposomes are expected to hold potential applications for the sensitive detection of various biomarkers in complicated serum samples.
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Imunoconjugados , Lipossomos , Anticorpos , Antígenos , Humanos , Imunoensaio , MasculinoRESUMO
During eukaryotic cell mitosis, the nuclear envelope disintegrates and transcription factors are dissociated from condensed chromosomes. Here, we describe a protocol to study centrosomal translocation of nuclear receptor RXRα. We detail procedures for HeLa cell synchronization followed by immunofluorescence, in situ proximity ligation assay, and centrosome isolation. This protocol can be used to identify other transcription factors associated with the centrosome or other subcellular structures during mitotic progression. For complete details on the use and execution of this protocol, please refer to Xie et al. (2020).
Assuntos
Centrossomo/metabolismo , Mitose , Fatores de Transcrição/metabolismo , Células HeLa , Humanos , Frações Subcelulares/metabolismoRESUMO
Peroxisome proliferator-activated receptor gamma (PPARγ) is a valuable drug target for diabetic treatment and ligands of PPARγ have shown potent anti-diabetic efficacy. However, to overcome the severe side effects of current PPARγ-targeted drugs, novel PPARγ ligands need to be developed. Sulindac, an identified ligand of PPARγ, is widely used in clinic as a non-steroidal anti-inflammatory drug. To explore its potential application for diabetes, we designed and synthesized a series of sulindac derivatives to investigate their structure-activity relationship as PPARγ ligand and potential anti-diabetic effect. We found that meta-substitution in sulindac's benzylidene moiety was beneficial to PPARγ binding and transactivation. Z rather than E configuration of the benzylidene double bond endowed derivatives with the selectivity of PPARγ activation. The indene fluorine is essential for binding and regulating PPARγ. Compared with rosiglitazone, compound 6b with benzyloxyl meta-substitution and Z benzylidene double bond weakly induced adipogenesis and PPARγ-targeted gene expression. However, 6b potently improved glucose tolerance in a diabetic mice model. Unlike rosiglitazone, 6b was devoid of apparent toxicity to osteoblastic formation. Thus, we provided some useful guidelines for PPARγ-based optimization of sulindac and an anti-diabetic lead compound with less side effects.
Assuntos
Diabetes Mellitus Experimental/tratamento farmacológico , Desenho de Fármacos , Hipoglicemiantes/farmacologia , PPAR gama/agonistas , Sulindaco/farmacologia , Animais , Células Cultivadas , Diabetes Mellitus Experimental/metabolismo , Relação Dose-Resposta a Droga , Humanos , Hipoglicemiantes/síntese química , Hipoglicemiantes/química , Camundongos , Camundongos Endogâmicos C57BL , Estrutura Molecular , Ratos , Ratos Sprague-Dawley , Relação Estrutura-Atividade , Sulindaco/síntese química , Sulindaco/químicaRESUMO
The paradoxical roles of transforming growth factor-ß (TGFß) signaling and nuclear receptor Nur77 in colon cancer development are known but the underlying mechanisms remain obscure. Inhibitor of differentiation 1 (ID1) is a target gene of TGFß and a key promoter for colon cancer progression. Here, we show that Nur77 enhances TGFß/Smad3-induced ID1 mRNA expression through hindering Smurf2-mediated Smad3 mono-ubiquitylation, resulting in ID1 upregulation. In the absence of TGFß, however, Nur77 destabilizes ID1 protein by promoting Smurf2-mediated ID1 poly-ubiquitylation, resulting in ID1 downregulation. Interestingly, TGFß stabilizes ID1 protein by switching Nur77 interaction partners to inhibit ID1 ubiquitylation. This also endows TGFß with an active pro-tumorigenic action in Smad4-deficient colon cancers. Thus, TGFß converts Nur77's role from destabilizing ID1 protein and cancer inhibition to inducing ID1 mRNA expression and cancer promotion, which is highly relevant to colon cancer stemness, metastasis and oxaliplatin resistance. Our data therefore define the integrated duality of Nur77 and TGFß signaling in regulating ID1 expression and provide mechanistic insights into the paradoxical roles of TGFß and Nur77 in colon cancer progression.
Assuntos
Neoplasias do Colo/etiologia , Neoplasias do Colo/metabolismo , Proteína 1 Inibidora de Diferenciação/metabolismo , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Animais , Carcinogênese , Linhagem Celular Tumoral , Neoplasias do Colo/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Células HCT116 , Células HT29 , Humanos , Proteína 1 Inibidora de Diferenciação/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Nus , Modelos Biológicos , Estabilidade Proteica , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Transdução de Sinais , Proteína Smad3/metabolismo , Proteína Smad4/deficiência , Proteína Smad4/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , UbiquitinaçãoRESUMO
Lung cancer is the leading cause of cancer deaths in the world. Non-small cell lung cancer (NSCLC), with poor prognosis and resistance to chemoradiotherapy, is the most common histological type of lung cancer. Therefore, it is necessary to develop new and more effective treatment strategy for NSCLC. Nur77, an orphan member of the nuclear receptor superfamily, induces apoptosis in cancer cells including NSCLC cells, by high expression and translocation to mitochondria. Small molecules trigger expression and mitochondrial localization of Nur77 may be an ideal anti-cancer drug candidate. Here, we report malayoside, a cardiac glycoside in the extract of Antiaris toxicaria Lesch., had different sensitivities to NSCLC cells. Malayoside induced apoptosis in NCI-H460 cells. Meanwhile, malayoside induced Nur77 expression and mitochondrial localization, and its induction of apoptosis was Nur77-dependent. To investigate the molecular mechanism of malayoside inducing Nur77 and apoptosis, we found that malayoside activated MAPK signaling pathway, including both ERK and p38 phosphorylation. The suppression of MAPK signaling activation inhibited the expression of Nur77 and apoptosis induced by malayoside. Our studies in nude mice showed that malayside potently inhibited the growth of tumor cells in vivo. Furthermore, the anti-cancer effect of malayosidwas in vivo was also related to the elevated expression of Nur77, p-ERK, and p-p38 proteins. Our results suggest that malayoside possesses an anti-NSCLC activity in vitro and in vivo mainly via activation of MAPK-Nur77 signaling pathway, indicating that malayoside is a promising chemotherapeutic candidate for NSCLC.
Assuntos
Antiaris/química , Apoptose/efeitos dos fármacos , Glicosídeos Cardíacos/farmacologia , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Animais , Carcinoma Pulmonar de Células não Pequenas , Glicosídeos Cardíacos/química , Linhagem Celular Tumoral , Proliferação de Células , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/metabolismo , Camundongos , Camundongos Nus , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/genética , Fitoterapia , Transporte Proteico/efeitos dos fármacosRESUMO
Although different types of drugs are available for postmenopausal osteoporosis, the limitations of the current therapies including drug resistances and adverse effects require identification of novel anti-osteoporosis agents. Here, we defined that norlichexanthone (NOR), a natural product, is a ligand of estrogen receptor-alpha (ERα) and revealed its therapeutic potential for postmenopausal osteoporosis. We used mammalian-one hybrid assay to screen for ERα modulators from crude extracts of several plant endophytes. As a result, NOR purified from the extract of endophyte ARL-13 was identified as a selective ERα modulator. NOR directly bound to ERα with an affinity in nanomolar range, revealing that it is a natural ligand of ERα. NOR induced osteoblast formation in MC3T3-E1 precursor cells. Conversely, NOR inhibited receptor activator of nuclear factor-kappa B ligand (RANKL)-induced osteoclast formation in both RAW264.7 macrophages and mouse primary monocytes. Mechanistically, NOR inhibited RANKL-induced association of ERα and TRAF6 to prevent ERα-mediated TRAF6 activation via Lys63-linked ubiquitination. Importantly, NOR exhibited potent anti-osteoporosis efficacy in an ovariectomized mouse model. Comparing to estrogen, NOR was of much less capability in stimulating endometrial hyperplasia and promoting mammalian cancer cell proliferation. Taken together, our study identified NOR as a natural and high affinity ligand of ERα with substantial anti-osteoporosis but less estrogenic activity.
RESUMO
Fluorophore-antibody conjugates with high photobleaching resistance, high chemical stability, and Fc-specific attachment is a great advantage for immunofluorescence imaging. Here, an Fc-binding protein (Z-domain) carrying a photo-cross-linker (p-benzoylphenylalanine, Bpa) fused with enhanced green fluorescent protein (EGFP), namely photoactivatable ZBpa-EGFP recombinant, was directly generated using the aminoacyl-tRNA synthetase/suppressor tRNA technique without any further modification. By employing the photoactivatable ZBpa-EGFP, an optimal approach was successfully developed which enabled EGFP to site-selectively and covalently attach to native antibody (IgG) with approximately 90% conjugation efficiency. After characterizing the Fc-specific and covalent manner of the EGFP-photoconjugated antibody, its excellent photobleaching resistance for immunofluorescence imaging was demonstrated in a model study by monitoring the toll-like receptor 4 (TLR4) expression in HepG2 cells. The proposed approach here for the preparation of a novel fluorescent antibody is available and reliable, which would play an important role in fluorescence immunoassay, and is expected to be extended to the generation of other biomolecule-photoconjugated antibodies, such as other fluorescent proteins for multiplex immunofluorescence imaging or reporter enzymes for highly sensitive enzyme immunoassays.Graphical abstract.