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Needing and seeking health information often is a longitudinal everyday life information behavior that involves the use of technology. However, no reviews of consumers' longitudinal health information needs (HIN) and health information-seeking (HIS) behavior have been conducted. We performed a scoping review to address this gap. Specifically, we surveyed the characteristics, timeline construction and research findings of studies investigating consumers' longitudinal HIN and HIS. Initial searches were conducted in November 2019 and updated in July 2022. A total of 128 papers were identified, reviewed and analyzed using content and thematic analyses. Results showed that most papers were quantitative, conducted in the USA, related to cancer, conducted during the diagnosis and treatment phases, and followed preset time intervals. Findings concerning the development patterns of consumers' HIN degrees and HIS effort were mixed (i.e. increasing, decreasing or being consistent over time). They seemed to be shaped by factors such as health conditions, data collection methods and the length of data collection. Consumers' use of sources changes depending on health status and source accessibility; their medical terminologies seem to expand over time. HIS has a strong emotional dimension which may lead to adaptive or maladaptive information behaviors (e.g. information avoidance). Overall, the results revealed a lack of understanding of HIN and HIS from a longitudinal perspective, particularly along health condition progression and coping trajectories. There is also a lack of understanding of the role of technologies in the longitudinal HIS process.
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Adaptação Psicológica , Informação de Saúde ao Consumidor , Humanos , Coleta de Dados , Emoções , Comportamentos Relacionados com a SaúdeRESUMO
Sorafenib is a small molecule that blocks tumor proliferation by targeting the activity of multi-kinases for the treatment of advanced hepatocellular carcinoma (HCC). Increasing sorafenib resistance following long-term treatment is frequently encountered. Mechanisms underlying sorafenib resistance remain not completely clear. To further understand the mechanism of sorafenib resistance in HCC, we established sorafenib-resistant cell lines by slowly increasing sorafenib concentration in cell culture medium. Upregulation of USP22 and ABCC1 were found in Sorafenib-resistant cells. Sorafenib-resistant cells treated with USP22 siRNA showed significant reduction in endogenous mRNA and protein levels of ABCC1. During sorafenib treatment, upregulation of USP22 increases ABCC1 expression and subsequently contributes to sorafenib resistance in HCC cells. Immunohistochemical analysis revealed a positive correlation between USP22 and ABCC1 expression in tissue samples from sorafenib-resistant patients (Pearson's correlation = 0.59, p = 0.03). Our findings indicate that upregulation of USP22 and ABCC1 expression during treatment contribute to sorafenib resistance in HCC cells and that USP22 has strong potential as a therapeutic target for overcoming sorafenib resistance in HCC patients.
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Carcinoma Hepatocelular , Neoplasias Hepáticas , Proteínas Associadas à Resistência a Múltiplos Medicamentos , Ubiquitina Tiolesterase , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos/genética , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Proteínas Associadas à Resistência a Múltiplos Medicamentos/metabolismo , Sorafenibe/farmacologia , Sorafenibe/uso terapêutico , Ubiquitina Tiolesterase/genética , Ubiquitina Tiolesterase/metabolismo , Regulação para CimaRESUMO
Lymphoid enhancer factor 1 (LEF1) activity is associated with progression of several types of cancers. The role of LEF1 in progression of hepatocellular carcinoma (HCC) remains poorly known. We investigated LEF1 expression in HCC and its interactions with epithelial-mesenchymal transition (EMT) regulators (e.g., Snail, Slug, Twist) and stemness genes (e.g., octamer-binding transcription factor 4 [Oct4], sex determining region Y-box 2 [Sox2], Nanog homeobox [Nanog]). Microarray analysis was performed on resected tumor samples from patients with HCC with or without postoperative recurrence. LEF1 expression was associated with postoperative recurrence as validated by immunohistochemical staining in another HCC cohort. Among 74 patients, 44 displayed a relatively high percentage of LEF1 staining (>30% of HCC cells), which was associated with a reduced recurrence-free interval (P < 0.001) and overall survival (P = 0.009). In multivariate analysis, a high percentage of LEF1 staining was significantly associated with low albumin level (P = 0.035), Twist overexpression (P = 0.018), Snail overexpression (P = 0.064), co-expression of Twist and Snail (P = 0.054), and multinodular tumors (P = 0.025). Down-regulation of LEF1 by short hairpin RNA decreased tumor sphere formation, soft agar colony formation, and transwell invasiveness of HCC cell lines Mahlavu and PLC. Xenotransplant and tail vein injection experiments revealed that LEF1 down-regulation in Mahlavu reduced tumor size and metastasis. LEF1 up-regulation in Huh7 increased sphere formation, soft agar colony formation, and transwell invasiveness. LEF1 was shown to physically interact with and transcriptionally activate promoter regions of Oct4, Snail, Slug, and Twist. Furthermore, Oct4, Snail, and Twist transactivated LEF1 to form a regulatory positive-feedback loop. Conclusion: LEF1 plays a pivotal role in HCC progression through transcriptional regulation of Oct4 and EMT regulators.
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[This corrects the article DOI: 10.18632/oncotarget.1994.].
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Rhodostomin (Rho) is a medium disintegrin containing a 48PRGDMP motif. We here showed that Rho proteins with P48A, M52W, and P53N mutations can selectively inhibit integrin αIIbß3. To study the roles of the RGD loop and C-terminal region in disintegrins, we expressed Rho 48PRGDMP and 48ARGDWN mutants in Pichia pastoris containing 65P, 65PR, 65PRYH, 65PRNGLYG, and 65PRNPWNG C-terminal sequences. The effect of C-terminal region on their integrin binding affinities was αIIbß3 > αvß3 ≥ α5ß1, and the 48ARGDWN-65PRNPWNG protein was the most selective integrin αIIbß3 mutant. The 48ARGDWN-65PRYH, 48ARGDWN-65PRNGLYG, and 48ARGDWN-65PRNPWNG mutants had similar activities in inhibiting platelet aggregation and the binding of fibrinogen to platelet. In contrast, 48ARGDWN-65PRYH and 48ARGDWN-65PRNGLYG exhibited 2.9- and 3.0-fold decreases in inhibiting cell adhesion in comparison with that of 48ARGDWN-65PRNPWNG. Based on the results of cell adhesion, platelet aggregation and the binding of fibrinogen to platelet inhibited by ARGDWN mutants, integrin αIIbß3 bound differently to immobilized and soluble fibrinogen. NMR structural analyses of 48ARGDWN-65PRYH, 48ARGDWN-65PRNGLYG, and 48ARGDWN-65PRNPWNG mutants demonstrated that their C-terminal regions interacted with the RGD loop. In particular, the W52 sidechain of 48ARGDWN interacted with H68 of 65PRYH, L69 of 65PRNGLYG, and N70 of 65PRNPWNG, respectively. The docking of the 48ARGDWN-65PRNPWNG mutant into integrin αIIbß3 showed that the N70 residue formed hydrogen bonds with the αIIb D159 residue, and the W69 residue formed cation-π interaction with the ß3 K125 residue. These results provide the first structural evidence that the interactions between the RGD loop and C-terminus of medium disintegrins depend on their amino acid sequences, resulting in their functional differences in the binding and selectivity of integrins.
Assuntos
Integrinas/fisiologia , Oligopeptídeos/farmacologia , Peptídeos/farmacologia , Plaquetas/efeitos dos fármacos , Células Cultivadas , Humanos , Espectrometria de Massas , Mutação , Oligopeptídeos/química , Peptídeos/química , Peptídeos/genética , Agregação Plaquetária/efeitos dos fármacos , Conformação Proteica , Homologia de Sequência de AminoácidosRESUMO
MST3 (mammalian STE20-like kinase 3) belongs to the Ste20 serine/threonine protein kinase family. The role of MST3 in tumor growth is less studied; therefore, we investigates the function of MST3 in breast cancer. Here, we demonstrate that MST3 is overexpressed in human breast tumors. Online Kaplan-Meier plotter analysis reveals that overexpression of MST3 predicts poor prognosis in breast cancer patients. Knockdown of MST3 with shRNA inhibits proliferation and anchorage-independent growth in vitro. Downregulation of MST3 in triple-negative MDA-MB-231 and MDA-MB-468 breast cancer cells decreases tumor formation in NOD/SCID mice. MST3 interacts with VAV2, but not VAV3, as demonstrated by co-immunoprecipitation and confocal microscopy. By domain mapping of MST3, we determine that the proline-rich region of MST3 (353KDIPKRP359) interacts with the SH3 domain of VAV2. Mutation of the two proline residues in this domain significantly attenuates the interaction between MST3 and VAV2. Overexpression of wild-type MST3 (WT-MST3), but not proline-rich-deleted MST3 (âP-MST3), enhances the proliferation rate and anchorage-independent growth of MDA-MB-468 cells. Overexpression of MST3 increases VAV2 phosphorylation and GTP-Rac1, whereas downregulation of MST3 or delivery of âP-MST3 results in a reduction of VAV2 and Rac1 activation. Knockdown of MST3 inhibits cyclin D1 protein expression. The Rac1 inhibitor EHop-016 attenuates cell proliferation induced by WT-MST3. Finally, Knockdown of MST3 or Rac1 inhibitor decreases cyclin D protein expression, which is important for tumor growth. These results indicate that MST3 interacts with VAV2 to activate Rac1 and promote the tumorigenicity of breast cancer.
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Biomarcadores Tumorais/metabolismo , Neoplasias da Mama/patologia , Proliferação de Células , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas c-vav/metabolismo , Proteínas rac1 de Ligação ao GTP/metabolismo , Animais , Apoptose , Biomarcadores Tumorais/genética , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Movimento Celular , Feminino , Humanos , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Estadiamento de Neoplasias , Prognóstico , Proteínas Serina-Treonina Quinases/genética , Proteínas Proto-Oncogênicas c-vav/genética , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto , Proteínas rac1 de Ligação ao GTP/genéticaRESUMO
CD90 is used as a marker for cancer stem cell in liver cancer. We aimed to study the mechanism by which CD90 promoted liver cancer progression and identify the new therapeutic targets on CD90 signal pathway. Ectopic expression of CD90 in liver cancer cell lines enhanced anchorage-independent growth and tumor progression. Furthermore, CD90 promoted sphere formation in vitro and upregulated the expression of the cancer stem cell marker CD133. The CD133 expression was higher in CD45-CD90+ cells in liver cancer specimen. The natural carcinogenic molecules TGF-ß-1, HGF, and hepatitis B surface antigen increased the expression of CD90 and CD133. Inhibition of CD90 by either shRNA or antibody attenuated the induction of CD133 and anchorage-independent growth. Lentiviral delivery of CD133 shRNA abolished the tumorigenicity induced by CD90. Ectopic expression of CD90 induced mTOR phosphorylation and AMPK dephosphorylation. Mutation of integrin binding-RLD domain in CD90 attenuated the induction of CD133 and anchorage-independent growth. Similar results were observed after silencing ß3 integrin. Signaling analyses revealed that AMPK/mTOR and ß3 integrin were required for the induction of CD133 and tumor formation by CD90. Importantly, the energy restriction mimetic agent OSU-CG5 reduced the CD90 population in fresh liver tumor sample and repressed the tumor growth. In contrast, sorafenib did not decrease the CD90+ population. In conclusion, the signal axis of CD90-integrin-mTOR/AMPK-CD133 is critical for promoting liver carcinogenesis. Molecules inhibiting the signal axis, including OSU-CG5 and other inhibitors, may serve as potential novel cancer therapeutic targets in liver cancer.
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Antineoplásicos/farmacologia , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/patologia , Terapia de Alvo Molecular/métodos , Transdução de Sinais/fisiologia , Tiazolidinedionas/farmacologia , Antígeno AC133 , Proteínas Quinases Ativadas por AMP/metabolismo , Animais , Antígenos CD/metabolismo , Western Blotting , Carcinogênese/efeitos dos fármacos , Carcinoma Hepatocelular/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/fisiologia , Citometria de Fluxo , Técnicas de Silenciamento de Genes , Glicoproteínas/metabolismo , Humanos , Integrinas/metabolismo , Neoplasias Hepáticas/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Peptídeos/metabolismo , Reação em Cadeia da Polimerase , RNA Interferente Pequeno , Transdução de Sinais/efeitos dos fármacos , Antígenos Thy-1/metabolismo , Transfecção , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Dysregulation of the EGFR signaling axis enhances bone metastases in many solid cancers. However, the relevant downstream effector signals in this axis are unclear. miR-1 was recently shown to function as a tumor suppressor in prostate cancer cells, where its expression correlated with reduced metastatic potential. In this study, we demonstrated a role for EGFR translocation in regulating transcription of miR-1-1, which directly targets expression of TWIST1. Consistent with these findings, we observed decreased miR-1 levels that correlated with enhanced expression of activated EGFR and TWIST1 in a cohort of human prostate cancer specimens and additional datasets. Our findings support a model in which nuclear EGFR acts as a transcriptional repressor to constrain the tumor-suppressive role of miR-1 and sustain oncogenic activation of TWIST1, thereby leading to accelerated bone metastasis.
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Neoplasias Ósseas/secundário , Receptores ErbB/metabolismo , MicroRNAs/metabolismo , Proteínas Nucleares/metabolismo , Neoplasias da Próstata/patologia , Proteína 1 Relacionada a Twist/metabolismo , Regiões 3' não Traduzidas , Animais , Neoplasias Ósseas/genética , Neoplasias Ósseas/patologia , Linhagem Celular Tumoral , Regulação para Baixo , Receptores ErbB/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Camundongos Nus , MicroRNAs/genética , Proteínas Nucleares/genética , Regiões Promotoras Genéticas , Neoplasias da Próstata/genética , Estabilidade de RNA , Proteína 1 Relacionada a Twist/genética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Aberrant activation of Ras and WNT signaling are key events that have been shown to be up-regulated in prostate cancer that has metastasized to the bone. However, the regulatory mechanism of combinatorial Ras and WNT signaling in advanced prostate cancer is still unclear. TCF7, a WNT signaling-related gene, has been implicated as a critical factor in bone metastasis, and here we show that TCF7 is a direct target of miR-34a. In samples of prostate cancer patients, miR-34a levels are inversely correlated with TCF7 expression and a WNT dependent gene signature. Ectopic miR-34a expression inhibited bone metastasis and reduced cancer cell proliferation in a Ras-dependent xenograft model. We demonstrate that miR-34a can directly interfere with the gene expression of the anti-proliferative BIRC5, by targeting BIRC5 3'UTR. Importantly, BIRC5 overexpression was sufficient to reconstitute anti-apoptotic signaling in cells expressing high levels of miR-34a. In prostate cancer patients, we found that BIRC5 levels were positively correlated with a Ras signaling signature expression. Our data show that the bone metastasis and anti-apoptotic effects found in Ras signaling-activated prostate cancer cells require miR-34a deficiency, which in turn aids in cell survival by activating the WNT and anti-apoptotic signaling pathways thereby inducing TCF7 and BIRC5 expressions.
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Neoplasias Ósseas/secundário , Regulação Neoplásica da Expressão Gênica/genética , MicroRNAs/metabolismo , Neoplasias da Próstata/patologia , Transdução de Sinais , Fator 1 de Transcrição de Linfócitos T/metabolismo , Animais , Western Blotting , Neoplasias Ósseas/genética , Neoplasias Ósseas/metabolismo , Linhagem Celular Tumoral , Xenoenxertos , Humanos , Imuno-Histoquímica , Proteínas Inibidoras de Apoptose/genética , Proteínas Inibidoras de Apoptose/metabolismo , Masculino , Camundongos , Camundongos Nus , MicroRNAs/genética , Invasividade Neoplásica/genética , Invasividade Neoplásica/patologia , Reação em Cadeia da Polimerase , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Transdução de Sinais/fisiologia , Survivina , Fator 1 de Transcrição de Linfócitos T/genética , Transfecção , Proteínas Wnt/genética , Proteínas Wnt/metabolismo , Proteínas ras/genética , Proteínas ras/metabolismoRESUMO
Activation of EGFR signaling pathway leads to prostate cancer bone metastasis; however, therapies targeting EGFR have demonstrated limited effectiveness and led to drug resistance. miR-203 levels are down-regulated in clinical samples of primary prostate cancer and further reduced in metastatic prostate cancer. Here we show that ectopic miR-203 expression displayed reduced bone metastasis and induced sensitivity to tyrosine kinase inhibitors (TKIs) treatment in a xenograft model. Our results demonstrate that the induction of bone metastasis and TKI resistance require miR-203 down regulation, activation of the EGFR pathway via altered expression of EGFR ligands (EREG and TGFA) and anti-apoptotic proteins (API5, BIRC2, and TRIAP1). Importantly, a sufficient reconstitution of invasiveness and resistance to TKIs treatment was observed in cells transfected with anti-miR-203. In prostate cancer patients, our data showed that miR-203 levels were inversely correlated with the expression of two EGFR ligands, EREG and TGFA, and an EGFR dependent gene signature. Our results support the existence of a miR-203, EGFR, TKIs resistance regulatory network in prostate cancer progression. We propose that the loss of miR-203 is a molecular link in the progression of prostate cancer metastasis and TKIs resistance characterized by high EGFR ligands output and anti-apoptotic proteins activation.
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Neoplasias Ósseas/secundário , Receptores ErbB/metabolismo , MicroRNAs/metabolismo , Neoplasias da Próstata/patologia , Regiões 3' não Traduzidas , Anfirregulina , Animais , Sequência de Bases , Neoplasias Ósseas/enzimologia , Neoplasias Ósseas/genética , Linhagem Celular Tumoral , Regulação para Baixo , Família de Proteínas EGF/genética , Família de Proteínas EGF/metabolismo , Epirregulina/genética , Epirregulina/metabolismo , Receptores ErbB/antagonistas & inibidores , Xenoenxertos , Humanos , Masculino , Camundongos , Camundongos Nus , MicroRNAs/biossíntese , MicroRNAs/genética , Dados de Sequência Molecular , Metástase Neoplásica , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas/biossíntese , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas p21(ras) , Transdução de Sinais , Fator de Crescimento Transformador alfa/genética , Fator de Crescimento Transformador alfa/metabolismo , Proteínas ras/biossíntese , Proteínas ras/genética , Proteínas ras/metabolismoRESUMO
Dysregulated metabolism is an emerging hallmark of cancer development, and upregulated lipid synthesis is one of the important tumor metabolic features. However, lipolysis may also contribute to cancer pathogenesis by altering free fatty acid (FFA) metabolism. In the present study, we investigated the importance of the lipolytic enzyme acyl-CoA thioesterase 8 (ACOT8) in hepatocellular carcinoma (HCC) development. Bioinformatic analysis of published microarrays regarding clinical specimens revealed that both ACOT8 gene copy number and mRNA expression were increased in HCC tissues when compared to these variables in non-tumor tissues. ACOT8 silencing with specific shRNA stably expressed in Huh7 and Hep3B HCC cell lines showed that ACOT8 protein expression and overall thioesterase activity were reduced following ACOT8 knockdown. In vitro tumorigenic assays revealed that ACOT8 knockdown inhibited anchorage-dependent and independent growth of HCC cell lines. This growth inhibition was partially rescued by addition of the FFA, myristic acid, indicating the importance of FFA in cancer metabolism. In summary, lipolytic enzyme ACOT8 is frequently upregulated in HCC clinical specimens. More importantly, ACOT8 silencing leads to inhibition of cell growth in HCC in vitro.
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Carcinoma Hepatocelular/genética , Proliferação de Células/genética , Neoplasias Hepáticas/genética , Palmitoil-CoA Hidrolase/biossíntese , Carcinoma Hepatocelular/patologia , Ácidos Graxos/metabolismo , Regulação Neoplásica da Expressão Gênica , Células Hep G2 , Humanos , Neoplasias Hepáticas/patologia , Palmitoil-CoA Hidrolase/genética , Proteômica , RNA MensageiroRESUMO
Arginine biosynthesis and nitric oxide (NO) production are important for cancer homeostasis. Degradation of arginine may be used to inhibit liver tumors with low argininosuccinate synthetase (ASS) expression. In this report, we investigated an alternative therapeutic approach by targeting argininosuccinate lyase (ASL). ASL is transcriptionally induced by endoplasmic reticulum stress and is overexpressed in some human liver tumors. Knockdown of ASL expression by short hairpin RNA (shRNA) in three liver cancer cell lines, ML-1, HuH-7, and HepG2, decreased colony formation in vitro and tumor growth in vivo. Furthermore, lentiviral infection of ASL shRNA inhibited tumor growth in a therapeutic animal tumor model. Analysis of ASL shRNA on the cell-cycle progression revealed a G2-M delay. Among cell-cycle regulatory molecules, cyclin A2 expression was reduced. Reintroduction of exogenous cyclin A2 restored the cell growth in ASL-knockdown cells. Autophagy was observed in the cells treated with ASL shRNA, as shown by an increase in LC3-II levels and autophagosome formation. The total cellular arginine level was not altered significantly. Inhibition of autophagy further attenuated cell growth, suggesting that autophagy induced by ASL shRNA plays a feedback prosurvival function. Knockdown of ASL reduced NO content, and addition of NO donor partially recovered the growth inhibition by ASL shRNA. In summary, downregulation of ASL attenuated tumor growth and the inhibition was mainly mediated by a decrease of cyclin A2 and NO.
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Argininossuccinato Liase/metabolismo , Carcinoma Hepatocelular/metabolismo , Ciclina A2/metabolismo , Neoplasias Hepáticas/metabolismo , Óxido Nítrico/metabolismo , RNA Interferente Pequeno/farmacologia , Animais , Arginina/metabolismo , Argininossuccinato Liase/genética , Autofagia/efeitos dos fármacos , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Ciclina A2/genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Humanos , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas Experimentais , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos NOD , Camundongos SCID , Óxido Nítrico/genéticaRESUMO
Dendroaspin (Den) and rhodostomin (Rho) are snake venom proteins containing a PRGDMP motif. Although Den and Rho have different 3D structures, they are highly potent integrin inhibitors. To study their structure, function, and dynamics relationships, we expressed Den and Rho in Pichia pastoris. The recombinant Den and Rho inhibited platelet aggregation with the K(I) values of 149.8 and 83.2 nM. Cell adhesion analysis showed that Den was 3.7 times less active than Rho when inhibiting the integrin αIIbß3 and 2.5 times less active when inhibiting the integrin αvß3. In contrast, Den and Rho were similarly active when inhibiting the integrin α5ß1 with the IC50 values of 239.8 and 256.8 nM. NMR analysis showed that recombinant Den and Rho have different 3D conformations for their arginyl-glycyl-aspartic acid (RGD) motif. However, the comparison with Rho showed that the docking of Den into integrin αvß3 resulted in a similar number of contacts. Analysis of the dynamic properties of the RGD loop in Den and Rho showed that they also had different dynamic properties. These results demonstrate that protein scaffolds affect the function, structure, and dynamics of their RGD motif.
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Venenos Elapídicos/química , Venenos Elapídicos/farmacologia , Integrinas/metabolismo , Peptídeos/química , Peptídeos/farmacologia , Venenos de Serpentes/química , Venenos de Serpentes/farmacologia , Motivos de Aminoácidos , Animais , Plaquetas/citologia , Plaquetas/efeitos dos fármacos , Plaquetas/metabolismo , Adesão Celular/efeitos dos fármacos , Humanos , Integrina alfa5beta1/antagonistas & inibidores , Integrina alfa5beta1/metabolismo , Integrina alfaVbeta3/antagonistas & inibidores , Integrina alfaVbeta3/metabolismo , Integrinas/antagonistas & inibidores , Modelos Moleculares , Oligopeptídeos/química , Agregação Plaquetária/efeitos dos fármacos , Inibidores da Agregação Plaquetária/química , Inibidores da Agregação Plaquetária/farmacologia , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/antagonistas & inibidores , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/metabolismo , Conformação Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/farmacologiaRESUMO
Echistatin (Ech) is a potent inhibitor of integrins and was isolated from snake Echis carinatus. To facilitate the study on the molecular determinants of integrin-ligand interactions, we expressed recombinant Ech and its mutants in the Pichia pastoris (P. pastoris) expression system and purified them to homogeneity with the yields of 2-7 mg/L. Ech produced in P. pastoris inhibited platelet aggregation with the IC(50) value of 210.5 nM. The sequential assignment and structure analysis of recombinant Ech were obtained by 2D and 3D (15)N-edited NMR spectra. These data suggests that Ech produced in P. pastoris retained its function and native fold. The results presented here provide the evidences that four disulfide-bonded peptide inhibitor of integrin, Ech, can be expressed in P. pastoris with correct fold and high yield. Platelet aggregation analysis of Ech mutants showed that the length of C-terminus and the K45 residue of Ech are important for interacting with integrin αIIbß3. We also found that recombinant Ech can inhibit the migration of human A375 melanoma cell. These findings may serve as the basis for understanding the activities of Ech.
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Desintegrinas/química , Oligopeptídeos/química , Peptídeos/química , Pichia/genética , Venenos de Víboras/química , Sequência de Bases , Primers do DNA , Eletroforese em Gel de Poliacrilamida , Peptídeos e Proteínas de Sinalização Intercelular , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Peptídeos/genética , Peptídeos/farmacologia , Agregação Plaquetária/efeitos dos fármacos , Inibidores da Agregação Plaquetária/química , Inibidores da Agregação Plaquetária/farmacologia , Reação em Cadeia da Polimerase , Relação Estrutura-AtividadeRESUMO
BACKGROUND: Induction of apoptosis by endoplasmic reticulum (ER) stress is implicated as the major factor in the development of multiple diseases. ER stress also appears to be a potentially useful major response to many chemotherapeutic drugs and environmental chemical compounds. A previous study has indicated that one major apoptotic regulator, p53, is significantly increased in response to ER stress, and participates in ER stress-induced apoptosis. However, the regulators of p53 expression during ER stress are still not fully understood. PRINCIPAL FINDINGS: In this report, we demonstrate that induction of p53 expression is mediated through NF-κB signaling pathways during ER stress in MCF-7 cells. Tunicamycin or brefeldin A, two ER stress inducers, increased p53 expression in MCF-7 and Hela cells. We found p53 nuclear localization, activity, and phosphorylation at serine 15 on p53 increased during ER stress. Nuclear translocation of NF-κB and activity of NF-κB were also observed during ER stress. ER stress-induced p53 expression was significantly inhibited by coincubation with the NF-κB inhibitor, Bay 11-7082 and downregulation of NF-κB p65 expression. The role of p53 in mediating Brefeldin A-induced apoptosis was also investigated. Induction of p53 expression by Brefeldin A was correlated to Brefeldin A-induced apoptosis. Furthermore, downregulation of p53 expression by p53 siRNA significantly reduced Brefeldin A-induced apoptosis in MCF-7 cells. SIGNIFICANCE: Taken together, NF-κB activation and induction of p53 expression is essential for ER stress-induced cell death which is important for therapeutic effects of clinical cancer drugs. Our results may provide insight into the mechanism of cancer chemotherapy efficacy that is associated with induction of ER stress.
Assuntos
Estresse do Retículo Endoplasmático , NF-kappa B/metabolismo , Ativação Transcricional , Proteína Supressora de Tumor p53/metabolismo , Apoptose , Brefeldina A/farmacologia , Cicloeximida/farmacologia , Dactinomicina/farmacologia , Quinase 3 da Glicogênio Sintase/metabolismo , Glicogênio Sintase Quinase 3 beta , Células HCT116 , Células HeLa , Humanos , Células MCF-7 , Fosforilação , Processamento de Proteína Pós-Traducional , Inibidores da Síntese de Proteínas/farmacologia , Transdução de Sinais , Transcrição Gênica/efeitos dos fármacos , Proteína Supressora de Tumor p53/genéticaRESUMO
Rhodostomin (Rho) is an RGD protein that specifically inhibits integrins. We found that Rho mutants with the P48A mutation 4.4-11.5 times more actively inhibited integrin α5ß1. Structural analysis showed that they have a similar 3D conformation for the RGD loop. Docking analysis also showed no difference between their interactions with integrin α5ß1. However, the backbone dynamics of RGD residues were different. The values of the R(2) relaxation parameter for Rho residues R49 and D51 were 39% and 54% higher than those of the P48A mutant, which caused differences in S(2), R(ex), and τ(e). The S(2) values of the P48A mutant residues R49, G50, and D51 were 29%, 14%, and 28% lower than those of Rho. The R(ex) values of Rho residues R49 and D51 were 0.91 s(-1) and 1.42 s(-1); however, no R(ex) was found for those of the P48A mutant. The τ(e) values of Rho residues R49 and D51 were 9.5 and 5.1 times lower than those of P48A mutant. Mutational study showed that integrin α5ß1 prefers its ligands to contain (G/A)RGD but not PRGD sequences for binding. These results demonstrate that the N-terminal proline residue adjacent to the RGD motif affect its function and dynamics, which suggests that the dynamic properties of the RGD motif may be important in Rho's interaction with integrin α5ß1.
Assuntos
Integrinas/metabolismo , Peptídeos/genética , Peptídeos/metabolismo , Domínios e Motivos de Interação entre Proteínas/genética , Alanina/genética , Substituição de Aminoácidos/fisiologia , Animais , Células CHO , Células Cultivadas , Cricetinae , Cricetulus , Humanos , Integrina alfa5beta1/química , Integrina alfa5beta1/metabolismo , Integrinas/química , Células K562 , Cinética , Modelos Moleculares , Mutagênese Sítio-Dirigida , Peptídeos/química , Mutação Puntual/fisiologia , Prolina/genética , Ligação Proteica/genética , Domínios e Motivos de Interação entre Proteínas/fisiologia , Serpentes/genéticaRESUMO
The endoplasmic reticulum (ER) is essential for lipid biosynthesis, and stress signals in this organelle are thought to alter lipid metabolism. Elucidating the mechanisms that underlie the dysregulation of lipid metabolism in hepatocytes may lead to novel therapeutic approaches for the treatment of lipid accumulation. We first tested the effects of several inhibitors on lipid dysregulation induced by tunicamycin, an ER stress inducer. Triacsin C, an inhibitor of long-chain acyl-CoA synthetase (ACSL) 1, 3, and 4, was the most potent among these inhibitors. We then analyzed the expression of the ACSL family during ER stress. The expression of ACSL3 was induced by ER stress in HuH-7 cells and in mice livers. ACSL3 shRNA, but not ACSL1 shRNA, inhibited the induction of lipid accumulation. GSK-3ß inhibitors attenuated ACSL3 expression and the lipid accumulation induced by ER stress in HuH-7 cells. shRNA that target GSK-3ß also inhibited the upregulation of ACSL3 and lipid accumulation in HuH-7 and HepG2 cells. The hepatitis B virus mutant large surface protein, which is known to induce ER stress, increased the lipid content of cells. Similarly, Triacsin C, and GSK-3ß inhibitors abrogated the lipid dysregulation caused by the hepatitis B virus mutant large surface protein. Altogether, ACSL3 and GSK-3ß represent novel therapeutic targets for lipid dysregulation by ER stress.
Assuntos
Coenzima A Ligases/metabolismo , Retículo Endoplasmático/fisiologia , Quinase 3 da Glicogênio Sintase/metabolismo , Hepatócitos/metabolismo , Lipídeos/biossíntese , Fígado/metabolismo , Animais , Linhagem Celular Tumoral , Chaperona BiP do Retículo Endoplasmático , Inibidores Enzimáticos/farmacologia , Glicogênio Sintase Quinase 3 beta , Proteínas de Choque Térmico/metabolismo , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Interferência de RNA , Estresse Fisiológico , Triazenos/farmacologia , Tunicamicina/farmacologia , Regulação para CimaRESUMO
Expression of mutant proteins or viral infection may interfere with proper protein folding activity in the endoplasmic reticulum (ER). Several pathways that maintain cellular homeostasis were activated in response to these ER disturbances. Here we investigated which of these ER stress-activated pathways induce COX-2 and potentially oncogenesis. Tunicamycin and brefeldin A, two ER stress inducers, increased the expression of COX-2 in ML-1 or MCF-7 cells. Nuclear translocation of NF-kappaB and activation of pp38 MAPK were observed during ER stress. IkappaBalpha kinase inhibitor Bay 11-7082 or IkappaBalpha kinase dominant negative mutant significantly inhibited the induction of COX-2. pp38 MAPK inhibitor SB203580 or eIF2alpha phosphorylation inhibitor 2-aminopurine attenuated the nuclear NF-kappaB DNA binding activity and COX-2 induction. Expression of mutant hepatitis B virus (HBV) large surface proteins, inducers of ER stress, enhanced the expression of COX-2 in ML-1 and HuH-7 cells. Transgenic mice showed higher expression of COX-2 protein in liver and kidney tissue expressing mutant HBV large surface protein in vivo. Similarly, increased expression of COX-2 mRNA was observed in human hepatocellular carcinoma tissue expressing mutant HBV large surface proteins. In ML-1 cells expressing mutant HBV large surface protein, anchorage-independent growth was enhanced, and the enhancement was abolished by the addition of specific COX-2 inhibitors. Thus, ER stress due either to expression of viral surface proteins or drugs can stimulate the expression of COX-2 through the NF-kappaB and pp38 kinase pathways. Our results provide important insights into cellular carcinogenesis associated with latent endoplasmic reticulum stress.