Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 117
Filtrar
Más filtros

Bases de datos
Tipo del documento
Intervalo de año de publicación
1.
J Am Chem Soc ; 146(5): 3052-3064, 2024 02 07.
Artículo en Inglés | MEDLINE | ID: mdl-38279916

RESUMEN

Fluorine NMR is a highly sensitive technique for delineating the conformational states of biomolecules and has shown great utility in drug screening and in understanding protein function. Current fluorinated protein tags leverage the intrinsic chemical shift sensitivity of the 19F nucleus to detect subtle changes in protein conformation and topology. This chemical shift sensitivity can be amplified by embedding the fluorine or trifluoromethyl reporter within a pyridone. Due to their polarizability and rapid tautomerization, pyridones exhibit a greater range of electron delocalization and correspondingly greater 19F NMR chemical shift dispersion. To assess the chemical shift sensitivity of these tautomeric probes to the local environment, 19F NMR spectra of all possible monofluorinated and trifluoromethyl-tagged versions of 2-pyridone were recorded in methanol/water mixtures ranging from 100% methanol to 100% water. 4-Fluoro-2-pyridone and 6-(trifluoromethyl)-2-pyridone (6-TFP) displayed the greatest sensitivity of the monofluorinated and trifluoromethylated pyridones, exceeding that of known conventional CF3 reporters. To evaluate the utility of tautomeric pyridone tags for 19F NMR of biomolecules, the alpha subunit of the stimulatory G protein (Gsα) and human serum albumin (HSA) were each labeled with a thiol-reactive derivative of 6-TFP and the spectra were recorded as a function of various adjuvants and drugs. The tautomeric tag outperformed the conventional tag, 2-bromo-N-(4-(trifluoromethyl)phenyl)acetamide through the improved resolution of several functional states.


Asunto(s)
Flúor , Metanol , Humanos , Flúor/química , Espectroscopía de Resonancia Magnética/métodos , Conformación Proteica , Agua , Piridonas
2.
Crit Rev Clin Lab Sci ; 60(4): 300-320, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-36846924

RESUMEN

Collectively known as psoriatic disease, psoriasis and psoriatic arthritis (PsA) are immune-mediated inflammatory diseases in which patients present with cutaneous and musculoskeletal inflammation. Affecting roughly 2-3% of the world's total population, there remains unmet therapeutic needs in both psoriasis and PsA despite the availability of current immunomodulatory treatments. As a result, patients with psoriatic disease often experience reduced quality of life. Recently, a class of small molecules, commonly investigated as anti-cancer agents, called histone deacetylase (HDAC) inhibitors, have been proposed as a new promising anti-inflammatory treatment for immune- and inflammatory-related diseases. In inflammatory diseases, current evidence is derived from studies on diseases like rheumatoid arthritis (RA) and systematic lupus erythematosus (SLE), and while there are some reports studying psoriasis, data on PsA patients are not yet available. In this review, we provide a brief overview of psoriatic disease, psoriasis, and PsA, as well as HDACs, and discuss the rationale behind the potential use of HDAC inhibitors in the management of persistent inflammation to suggest its possible use in psoriatic disease.


Asunto(s)
Artritis Psoriásica , Psoriasis , Humanos , Artritis Psoriásica/tratamiento farmacológico , Inhibidores de Histona Desacetilasas/uso terapéutico , Inflamación/tratamiento farmacológico , Psoriasis/tratamiento farmacológico , Calidad de Vida
3.
Exp Cell Res ; 411(1): 112731, 2022 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-34270980

RESUMEN

Adhesion of cells to each other and to the extracellular matrix (ECM) are both required for cellular functions. Cell-to-cell adhesion is mediated by cadherins, and their engagement triggers the activation of Stat3, which offers a potent survival signal. Adhesion to the ECM on the other hand, activates FAK which attracts and activates Src, as well as receptor tyrosine kinases (RTKs), the PI3k/Akt and Ras/Erk pathways. However, the effect of cell density upon FAK and Akt activity has not been examined. We now demonstrate that, interestingly, despite being potent Stat3 activators, Src and RTKs are unable to activate Stat3 in sparsely growing (i.e., without cadherin engagement), non-neoplastic cells attached to the ECM. In contrast, cell aggregation (i.e., cadherin engagement in the absence of adhesion to a solid substratum) was found to activate both Stat3 and Akt. Pharmacologic or genetic reduction of FAK activity abolished Akt activity at low densities, indicating that FAK is an important activator of Akt in this setting. Notably, FAK knockout increased cellular sensitivity to the Stat3 inhibitor CPA7, while FAK reintroduction restored resistance to this drug. These findings suggest a complementary role of integrin/FAK/Akt and cadherin/Stat3-mediated pro-survival pathways, which may be of significance during neoplastic transformation and metastasis.

4.
Nano Lett ; 22(18): 7285-7293, 2022 09 28.
Artículo en Inglés | MEDLINE | ID: mdl-36067362

RESUMEN

Achieving long-term (>3 months) colloidal stability of upconversion nanoparticles (UCNPs) in biologically relevant buffers has been a major challenge, which has severely limited practical implementation of UCNPs in bioimaging and nanomedicine applications. To address this challenge, nine unique copolymers formulations were prepared and evaluated as UCNP overcoatings. These polymers consisted of a poly(isobutylene-alt-maleic anhydride) (PIMA) backbone functionalized with different ratios and types of phosphonate anchoring groups and poly(ethylene glycol) (PEG) moieties. The syntheses were done as simple, one-pot nucleophilic addition reactions. These copolymers were subsequently coated onto NaYF4:Yb3+,Er3+ UCNPs, and colloidal stability was evaluated in 1 × PBS, 10 × PBS, and other buffers. UCNP colloidal stability improved (up to 4 months) when coated with copolymers containing greater proportions of anchoring groups and higher phosphonate valences. Furthermore, small molecules could be conjugated to these overcoated UCNPs by use of copper-free click chemistry, as was done to demonstrate suitability for sensor and bioprobe development.


Asunto(s)
Nanopartículas , Organofosfonatos , Nanopartículas/química , Polietilenglicoles/química , Polímeros/química , Yoduro de Potasio
5.
J Cell Mol Med ; 26(7): 2049-2062, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-35229974

RESUMEN

Through a comprehensive review and in silico analysis of reported data on STAT-linked diseases, we analysed the communication pathways and interactome of the seven STATs in major cancer categories and proposed rational targeting approaches for therapeutic intervention to disrupt critical pathways and addictions to hyperactive JAK/STAT in neoplastic states. Although all STATs follow a similar molecular activation pathway, STAT1, STAT2, STAT4 and STAT6 exert specific biological profiles associated with a more restricted pattern of activation by cytokines. STAT3 and STAT5A as well as STAT5B have pleiotropic roles in the body and can act as critical oncogenes that promote many processes involved in cancer development. STAT1, STAT3 and STAT5 also possess tumour suppressive action in certain mutational and cancer type context. Here, we demonstrated member-specific STAT activity in major cancer types. Through systems biology approaches, we found surprising roles for EGFR family members, sex steroid hormone receptor ESR1 interplay with oncogenic STAT function and proposed new drug targeting approaches of oncogenic STAT pathway addiction.


Asunto(s)
Neoplasias , Factores de Transcripción STAT , Citocinas/metabolismo , Receptores ErbB/metabolismo , Humanos , Neoplasias/genética , Factores de Transcripción STAT/genética , Factores de Transcripción STAT/metabolismo
6.
Exp Cell Res ; 404(1): 112601, 2021 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-33957118

RESUMEN

Adhesion of cells to each other and to the extracellular matrix (ECM) are both required for cellular functions. Cell-to-cell adhesion is mediated by cadherins and their engagement triggers the activation of Stat3, which offers a potent survival signal. Adhesion to the ECM on the other hand, activates FAK which attracts and activates Src, as well as receptor tyrosine kinases (RTKs), the PI3k/Akt and Ras/Erk pathways. However, the effect of cell density upon FAK and Akt activity has not been examined. We now demonstrate that, interestingly, despite being potent Stat3 activators, Src and RTKs are unable to activate Stat3 in sparsely growing (i.e., without cadherin engagement), non-neoplastic cells attached to the ECM. In contrast, cell aggregation (i.e., cadherin engagement in the absence of adhesion to a solid substratum) was found to activate both Stat3 and Akt. Pharmacologic or genetic reduction of FAK activity abolished Akt activity at low densities, indicating that FAK is an important activator of Akt in this setting. Notably, FAK knockout increased cellular sensitivity to the Stat3 inhibitor CPA7, while FAK reintroduction restored resistance to this drug. These findings suggest a complementary role of integrin/FAK/Akt and cadherin/Stat3-mediated pro-survival pathways, which may be of significance during neoplastic transformation and metastasis.


Asunto(s)
Cadherinas/metabolismo , Fibroblastos/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Factor de Transcripción STAT3/metabolismo , Animales , Adhesión Celular/fisiología , Supervivencia Celular/fisiología , Transformación Celular Neoplásica/metabolismo , Matriz Extracelular/metabolismo , Proteína-Tirosina Quinasas de Adhesión Focal/metabolismo , Humanos , Ratones , Fosfatidilinositol 3-Quinasas/metabolismo , Transducción de Señal/fisiología
7.
Chem Soc Rev ; 49(9): 2617-2687, 2020 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-32227030

RESUMEN

Over the past decade, covalent kinase inhibitors (CKI) have seen a resurgence in drug discovery. Covalency affords a unique set of advantages as well as challenges relative to their non-covalent counterpart. After reversible protein target recognition and binding, covalent inhibitors irreversibly modify a proximal nucleophilic residue on the protein via reaction with an electrophile. To date, the acrylamide group remains the predominantly employed electrophile in CKI development, with its incorporation in the majority of clinical candidates and FDA approved covalent therapies. Nonetheless, in recent years considerable efforts have ensued to characterize alternative electrophiles that exhibit irreversible or reversibly covalent binding mechanisms towards cysteine thiols and other amino acids. This review article provides a comprehensive overview of CKIs reported in the literature over a decade period, 2007-2018. Emphasis is placed on the rationale behind warhead choice, optimization approach, and inhibitor design. Current FDA approved CKIs are also highlighted, in addition to a detailed analysis of the common trends and themes observed within the listed data set.


Asunto(s)
Inhibidores Enzimáticos/farmacología , Fosfotransferasas/antagonistas & inhibidores , Sitios de Unión , Descubrimiento de Drogas , Inhibidores Enzimáticos/química , Modelos Moleculares , Conformación Proteica
8.
Haematologica ; 105(2): 435-447, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31123029

RESUMEN

Recurrent gain-of-function mutations in the transcription factors STAT5A and much more in STAT5B were found in hematopoietic malignancies with the highest proportion in mature T- and natural killer-cell neoplasms (peripheral T-cell lymphoma, PTCL). No targeted therapy exists for these heterogeneous and often aggressive diseases. Given the shortage of models for PTCL, we mimicked graded STAT5A or STAT5B activity by expressing hyperactive Stat5a or STAT5B variants at low or high levels in the hematopoietic system of transgenic mice. Only mice with high activity levels developed a lethal disease resembling human PTCL. Neoplasia displayed massive expansion of CD8+ T cells and destructive organ infiltration. T cells were cytokine-hypersensitive with activated memory CD8+ T-lymphocyte characteristics. Histopathology and mRNA expression profiles revealed close correlation with distinct subtypes of PTCL. Pronounced STAT5 expression and activity in samples from patients with different subsets underline the relevance of JAK/STAT as a therapeutic target. JAK inhibitors or a selective STAT5 SH2 domain inhibitor induced cell death and ruxolitinib blocked T-cell neoplasia in vivo We conclude that enhanced STAT5A or STAT5B action both drive PTCL development, defining both STAT5 molecules as targets for therapeutic intervention.


Asunto(s)
Leucemia , Linfoma de Células T Periférico , Animales , Linfocitos T CD8-positivos/metabolismo , Citocinas , Humanos , Linfoma de Células T Periférico/genética , Ratones , Factor de Transcripción STAT5/genética , Factor de Transcripción STAT5/metabolismo , Proteínas Supresoras de Tumor
9.
Mol Pain ; 15: 1744806918823477, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30799695

RESUMEN

Aggressive breast cancer subtypes utilize system xc-, a membrane antiporter, to import cystine for glutathione synthesis and maintenance of redox homeostasis, in turn releasing glutamate as a metabolic pro-nociceptive by-product. Metastatic breast cancers establish themselves at distal sites including bone, where changes in extracellular glutamate levels contribute to cancer-induced bone pain. We previously established that stearically blocking system xc- activity with sulfasalazine delays the onset of nociceptive behaviours and that xCT, the functional antiporter subunit, is positively regulated by signal transducer and activator of transcription 3 (STAT3). In the current investigation, a murine xenograft cancer-induced bone pain model was applied to examine whether pharmacological inhibition of phosphorylated STAT3 (pSTAT3) induces changes in nociception. A high glutamate-releasing, xCT/pSTAT3 over-expressing human breast cancer cell line was selected for injection into the distal epiphysis of the right femur of female nude mice. A 14-day regimen of intraperitoneal injections with either vehicle or the novel STAT3 inhibitor DR-1-55 commenced three weeks after initial intrafemoral bone injection. Nociceptive behaviours were temporally monitored by automated von Frey, dynamic weight bearing and open-field testing for the duration of the study, beginning at the baseline. Prior to sacrifice and at ethical end point, tumour-induced osteolytic lesions were radiographically assessed. Treatment with DR-1-55 significantly delayed the onset and severity of spontaneous and induced nociceptive behaviours, also decreasing human SLC7A11 ( xCT) mRNA levels in tumour-bearing limbs without altering osteolysis. In addition, two pro-inflammatory cytokines released by this cell line, interleukin 6 and interleukin 1ß, were also down-regulated at the mRNA level in response to DR-1-55 treatment in vivo, with lower human interleukin 6 levels detected in the host circulation. This study demonstrates that targeting pSTAT3 may be a viable therapeutic means to manage cancer-induced bone pain, alone or in combination with stearic system xc- blockers.


Asunto(s)
Huesos/patología , Dolor en Cáncer/metabolismo , Regulación Neoplásica de la Expresión Génica/fisiología , Nocicepción/fisiología , Factor de Transcripción STAT3/metabolismo , Animales , Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias Óseas/complicaciones , Neoplasias Óseas/tratamiento farmacológico , Neoplasias de la Mama/complicaciones , Dolor en Cáncer/etiología , Dolor en Cáncer/terapia , Carcinoma/complicaciones , Línea Celular Tumoral/patología , Citocinas/sangre , Citocinas/genética , Modelos Animales de Enfermedad , Conducta Exploratoria/efectos de los fármacos , Conducta Exploratoria/fisiología , Femenino , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Hiperalgesia/tratamiento farmacológico , Hiperalgesia/etiología , Masculino , Ratones , Ratones Desnudos , Nocicepción/efectos de los fármacos , Factor de Transcripción STAT3/antagonistas & inhibidores , Factor de Transcripción STAT3/genética , Soporte de Peso/fisiología , Ensayos Antitumor por Modelo de Xenoinjerto
10.
Biochem Cell Biol ; 97(5): 638-646, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-30986357

RESUMEN

We recently demonstrated that Cav1 (caveolin-1) is a negative regulator of Stat3 (signal transducer and activator of transcription-3) activity in mouse fibroblasts and human lung carcinoma SHP77 cells. We now examined whether the cellular context may affect their levels as well as the relationship between them, by assessing Cav1 and Stat3-ptyr705 amounts in different cell lines. In MDA-MB-231, A549, and HaCat cells, Cav1 levels were high and Stat3-ptyr705 levels were low, consistent with the notion of a negative effect of endogenous Cav1 on Stat3-ptyr705 levels in these lines. In addition, manipulation of Cav1 levels revealed a negative effect in MCF7 and mouse fibroblast cells, while Cav1 upregulation induced apoptosis in MCF7 cells. In contrast, however, line MRC9 had high Cav1 and high Stat3-ptyr705 levels, indicating that high Cav1 is insufficient to reduce Stat3-ptyr705 levels in this line. MCF7 and LuCi6 cells had very low Cav1 and Stat3-ptyr705 levels, indicating that the low Stat3-ptyr705 can be independent from Cav1 levels altogether. Our results reveal a further level of complexity in the relationship between Cav1 and Stat3-ptyr705 than previously thought. In addition, we demonstrate that in a feedback loop, Stat3 inhibition upregulates Cav1 in HeLa cells but not in other lines tested.


Asunto(s)
Neoplasias de la Mama/metabolismo , Caveolina 1/metabolismo , Neoplasias Pulmonares/metabolismo , Factor de Transcripción STAT3/metabolismo , Tirosina/metabolismo , Animales , Caveolina 1/antagonistas & inhibidores , Células Cultivadas , Femenino , Humanos , Ratones , Ratones Endogámicos BALB C
11.
Hepatology ; 67(1): 313-327, 2018 01.
Artículo en Inglés | MEDLINE | ID: mdl-28833283

RESUMEN

Transcriptional networks control the differentiation of the hepatocyte and cholangiocyte lineages from embryonic liver progenitor cells and their subsequent maturation to the adult phenotype. However, how relative levels of hepatocyte and cholangiocyte gene expression are determined during differentiation remains poorly understood. Here, we identify microRNA (miR)-337-3p as a regulator of liver development. miR-337-3p stimulates expression of cholangiocyte genes and represses hepatocyte genes in undifferentiated progenitor cells in vitro and in embryonic mouse livers. Beyond the stage of lineage segregation, miR-337-3p controls the transcriptional network dynamics of developing hepatocytes and balances both cholangiocyte populations that constitute the ductal plate. miR-337-3p requires Notch and transforming growth factor-ß signaling and exerts a biphasic control on the hepatocyte transcription factor hepatocyte nuclear factor 4α by modulating its activation and repression. With the help of an experimentally validated mathematical model, we show that this biphasic control results from an incoherent feedforward loop between miR-337-3p and hepatocyte nuclear factor 4α. CONCLUSION: Our results identify miR-337-3p as a regulator of liver development and highlight how tight quantitative control of hepatic cell differentiation is exerted through specific gene regulatory network motifs. (Hepatology 2018;67:313-327).


Asunto(s)
Diferenciación Celular/genética , Regulación del Desarrollo de la Expresión Génica , Factor Nuclear 1-alfa del Hepatocito/genética , Hepatocitos/metabolismo , MicroARNs/genética , Animales , Western Blotting , Células Cultivadas , Ratones , Transducción de Señal/genética , Estadísticas no Paramétricas , Factores de Transcripción
12.
FASEB J ; 32(6): 3301-3320, 2018 06.
Artículo en Inglés | MEDLINE | ID: mdl-29401627

RESUMEN

Intestinal mucins trigger immune responses upon recognition by dendritic cells via protein-carbohydrate interactions. We used a combination of structural, biochemical, biophysical, and cell-based approaches to decipher the specificity of the interaction between mucin glycans and mammalian lectins expressed in the gut, including galectin (Gal)-3 and C-type lectin receptors. Gal-3 differentially recognized intestinal mucins with different O-glycosylation profiles, as determined by mass spectrometry (MS). Modification of mucin glycosylation, via chemical treatment leading to a loss of terminal glycans, promoted the interaction of Gal-3 to poly- N-acetyllactosamine. Specific interactions were observed between mucins and mouse dendritic cell-associated lectin (mDectin)-2 or specific intercellular adhesion molecule-grabbing nonintegrin-related-1 (SIGN-R1), but not mDectin-1, using a cell-reporter assay, as also confirmed by atomic force spectroscopy. We characterized the N-glycosylation profile of mouse colonic mucin (Muc)-2 by MS and showed that the interaction with mDectin-2 was mediated by high-mannose N-glycans. Furthermore, we observed Gal-3 binding to the 3 C-type lectins by force spectroscopy. We showed that mDectin-1, mDectin-2, and SIGN-R1 are decorated by N-glycan structures that can be recognized by the carbohydrate recognition domain of Gal-3. These findings provide a structural basis for the role of mucins in mediating immune responses and new insights into the structure and function of major mammalian lectins.-Leclaire, C., Lecointe, K., Gunning, P. A., Tribolo, S., Kavanaugh, D. W., Wittmann, A., Latousakis, D., MacKenzie, D. A., Kawasaki, N., Juge, N. Molecular basis for intestinal mucin recognition by galectin-3 and C-type lectins.


Asunto(s)
Moléculas de Adhesión Celular/química , Galectina 3/química , Lectinas Tipo C/química , Mucina 2/química , Receptores de Superficie Celular/química , Animales , Proteínas Sanguíneas , Moléculas de Adhesión Celular/genética , Moléculas de Adhesión Celular/metabolismo , Galectina 3/genética , Galectina 3/metabolismo , Galectinas , Humanos , Lectinas Tipo C/genética , Lectinas Tipo C/metabolismo , Espectrometría de Masas , Ratones , Mucina 2/genética , Mucina 2/metabolismo , Dominios Proteicos , Receptores de Superficie Celular/genética , Receptores de Superficie Celular/metabolismo , Relación Estructura-Actividad
13.
Biomacromolecules ; 20(11): 4180-4190, 2019 11 11.
Artículo en Inglés | MEDLINE | ID: mdl-31518115

RESUMEN

Bacterial cellulose (BC) consists of a complex three-dimensional organization of ultrafine fibers which provide unique material properties such as softness, biocompatibility, and water-retention ability, of key importance for biomedical applications. However, there is a poor understanding of the molecular features modulating the macroscopic properties of BC gels. We have examined chemically pure BC hydrogels and composites with arabinoxylan (BC-AX), xyloglucan (BC-XG), and high molecular weight mixed-linkage glucan (BC-MLG). Atomic force microscopy showed that MLG greatly reduced the mechanical stiffness of BC gels, while XG and AX did not exert a significant effect. A combination of advanced solid-state NMR methods allowed us to characterize the structure of BC ribbons at ultra-high resolution and to monitor local mobility and water interactions. This has enabled us to unravel the effect of AX, XG, and MLG on the short-range order, mobility, and hydration of BC fibers. Results show that BC-XG hydrogels present BC fibrils of increased surface area, which allows BC-XG gels to hold higher amounts of bound water. We report for the first time that the presence of high molecular weight MLG reduces the density of clusters of BC fibrils and dramatically increases water interactions with BC. Our data supports two key molecular features determining the reduced stiffness of BC-MLG hydrogels, that is, (i) the adsorption of MLG on the surface of BC fibrils precluding the formation of a dense network and (ii) the preorganization of bound water by MLG. Hence, we have produced and fully characterized BC-MLG hydrogels with novel properties which could be potentially employed as renewable materials for applications requiring high water retention capacity (e.g. personal hygiene products).


Asunto(s)
Celulosa/química , Glucanos/química , Hidrogeles/farmacología , Bacterias/enzimología , Celulosa/farmacología , Glucanos/farmacología , Hidrogeles/química , Espectroscopía de Resonancia Magnética , Fenómenos Mecánicos/efectos de los fármacos , Microscopía de Fuerza Atómica , Peso Molecular , Xilanos/química , Xilanos/farmacología
14.
Exp Cell Res ; 361(1): 112-125, 2017 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-29031557

RESUMEN

It was previously demonstrated that differentiation of some established breast epithelial cell lines requires confluence and stimulation with hydrocortisone, insulin and prolactin inducers. We and others previously demonstrated that E-cadherin engagement, which is favored under conditions of confluence, increases the levels and activity of the Rac small GTPase. To investigate the functional relationship between the transforming ability of Rac and its role as an integral component of the differentiative E-cadherin signaling pathway, we introduced a mutationally activated form of Rac, RacV12, into the mouse breast epithelium-derived cell line, HC11. Our results demonstrate that the strength of the Rac signal is key for the outcome of the differentiation process; cRac1 is critically required for differentiation, and at low levels, mutationally activated RacV12 is able to increase differentiation, presumably reinforcing the E-cadherin/Rac differentiative signal. However, high RacV12 expression blocked differentiation concomitant with E-cadherin downregulation, while inducing neoplastic transformation. Therefore, the intensity of the Rac signal is a central determinant in the balance between cell proliferation vs differentiation, two fundamentally opposed processes, a finding which could also have important therapeutic implications.


Asunto(s)
Cadherinas/metabolismo , Diferenciación Celular , Células Epiteliales/citología , Glándulas Mamarias Animales/citología , Proteínas de Unión al GTP rac/metabolismo , Animales , Células Cultivadas , Células Epiteliales/metabolismo , Femenino , Glándulas Mamarias Animales/metabolismo , Ratones , Transducción de Señal
16.
Haematologica ; 102(9): 1519-1529, 2017 09.
Artículo en Inglés | MEDLINE | ID: mdl-28596283

RESUMEN

In chronic myeloid leukemia, resistance against BCR-ABL1 tyrosine kinase inhibitors can develop because of BCR-ABL1 mutations, activation of additional pro-oncogenic pathways, and stem cell resistance. Drug combinations covering a broad range of targets may overcome resistance. CDDO-Me (bardoxolone methyl) is a drug that inhibits the survival of leukemic cells by targeting different pro-survival molecules, including STAT3. We found that CDDO-Me inhibits proliferation and survival of tyrosine kinase inhibitor-resistant BCR-ABL1+ cell lines and primary leukemic cells, including cells harboring BCR-ABL1T315I or T315I+ compound mutations. Furthermore, CDDO-Me was found to block growth and survival of CD34+/CD38- leukemic stem cells (LSC). Moreover, CDDO-Me was found to produce synergistic growth-inhibitory effects when combined with BCR-ABL1 tyrosine kinase inhibitors. These drug-combinations were found to block multiple signaling cascades and molecules, including STAT3 and STAT5. Furthermore, combined targeting of STAT3 and STAT5 by shRNA and STAT5-targeting drugs also resulted in synergistic growth-inhibition, pointing to a new efficient concept of combinatorial STAT3 and STAT5 inhibition. However, CDDO-Me was also found to increase the expression of heme-oxygenase-1, a heat-shock-protein that triggers drug resistance and cell survival. We therefore combined CDDO-Me with the heme-oxygenase-1 inhibitor SMA-ZnPP, which also resulted in synergistic growth-inhibitory effects. Moreover, SMA-ZnPP was found to sensitize BCR-ABL1+ cells against the combination 'CDDO-Me+ tyrosine kinase inhibitor'. Together, combined targeting of STAT3, STAT5, and heme-oxygenase-1 overcomes resistance in BCR-ABL1+ cells, including stem cells and highly resistant sub-clones expressing BCR-ABL1T315I or T315I-compound mutations. Whether such drug-combinations are effective in tyrosine kinase inhibitor-resistant patients with chronic myeloid leukemia remains to be elucidated.


Asunto(s)
Sistemas de Liberación de Medicamentos , Resistencia a Antineoplásicos/efectos de los fármacos , Proteínas de Fusión bcr-abl/antagonistas & inhibidores , Leucemia Mielógena Crónica BCR-ABL Positiva/tratamiento farmacológico , Células Madre Neoplásicas/metabolismo , Inhibidores de Proteínas Quinasas/farmacología , Factor de Transcripción STAT3/antagonistas & inhibidores , Factor de Transcripción STAT5/antagonistas & inhibidores , Adulto , Anciano , Anciano de 80 o más Años , Línea Celular Tumoral , Resistencia a Antineoplásicos/genética , Proteínas de Fusión bcr-abl/genética , Proteínas de Fusión bcr-abl/metabolismo , Humanos , Leucemia Mielógena Crónica BCR-ABL Positiva/genética , Leucemia Mielógena Crónica BCR-ABL Positiva/metabolismo , Masculino , Persona de Mediana Edad , Células Madre Neoplásicas/patología , Factor de Transcripción STAT3/genética , Factor de Transcripción STAT3/metabolismo , Factor de Transcripción STAT5/genética , Factor de Transcripción STAT5/metabolismo
17.
Protein Expr Purif ; 129: 1-8, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-27590918

RESUMEN

STAT5B, a ubiquitious transcription factor, has been implicated in the onset and progression of several cancers. Since the inhibition of STAT activity holds significant therapeutic potential, there is a need to develop high-throughput biophysical screening platforms to rapidly identify high affinity binders of STATs. Biophysical assays would benefit from the efficient and cost-effective production of high purity, full-length STAT proteins. Herein, we have sampled a large region of protein expression and purification space that has substantially increased recombinant STAT5B protein yields from Escherichia coli. The identity of STAT5B was confirmed by Western blotting analysis, while the results of a fluorescence polarization assay indicated that the purified protein is correctly folded and functional. A thermal shift assay was employed to assess the effect of various osmolytes on the stability of the protein. The protein expression conditions identified in this study allowed for more efficient and higher recovery of soluble STAT5B protein, which will enable a broad range of biophysical studies and facilitate high-throughput STAT5B drug screening.


Asunto(s)
Escherichia coli/metabolismo , Expresión Génica , Factor de Transcripción STAT5 , Escherichia coli/genética , Humanos , Proteínas Recombinantes de Fusión/biosíntesis , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/aislamiento & purificación , Factor de Transcripción STAT5/biosíntesis , Factor de Transcripción STAT5/química , Factor de Transcripción STAT5/genética , Factor de Transcripción STAT5/aislamiento & purificación , Solubilidad
18.
Analyst ; 142(23): 4511-4521, 2017 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-29098228

RESUMEN

Membrane-embedded negatively charged phospholipids (MENCP) can be used as biomarkers for a range of biological processes, including early detection of apoptosis in animal cells, drug-induced phospholipidosis, and selective detection of bacterial over animal cells. Currently, several technologies for the detection of apoptosis and bacterial cells are based on the recognition of MENCPs, including the AnnexinV stain and PSVue™ probes. As probes, these technologies have limitations, the most significant of which is the need for washing the unbound probe away to achieve optimal signal. In contrast, a turn-on chemosensor selective for MENCP would address this shortcoming, and allow for a more rapid protocol for the detection of apoptosis, bacteria and for other relevant applications. In this work, the aim was to explore whether ProxyPhos chemosensors, previously reported by our group for the detection of proximally phosphorylated peptides and proteins, could be re-purposed for the detection of MENCPs. Six lead ProxyPhos sensors were screened against synthetic vesicles containing biologically relevant negatively charged phospholipids including phosphatidic acid (PA), phosphatidylglycerol (PG), cardiolipin (CL) and phosphatidylserine (PS). Through these screens, ProxyPhos sensors exhibiting high selectivity for the detection of MENCPs over zwitterionic lipids were identified. Particular selectivity was observed for PA and CL. Sensitivity of the lead sensors for MENCPs was suitable for the detection of apoptosis: ProxyPhos detected vesicles containing as little as 2.5% PS and detected camptothecin-induced apoptosis in mammalian cells in flow cytometry experiments. The results suggest that ProxyPhos sensors can be used for the detection of MENCPs in synthetic vesicles and live mammalian cells.


Asunto(s)
Membranas/química , Fosfolípidos/química , Apoptosis , Cardiolipinas , Línea Celular Tumoral , Humanos , Ácidos Fosfatidicos , Fosfatidilgliceroles , Fosfatidilserinas
19.
Gut ; 65(5): 821-9, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-25666195

RESUMEN

OBJECTIVE: Nearly 20%-29% of patients with colorectal cancer (CRC) succumb to liver or lung metastasis and there is a dire need for novel targets to improve the survival of patients with metastasis. The long isoform of the Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1-L or CC1-L) is a key regulator of immune surveillance in primary CRC, but its role in metastasis remains largely unexplored. We have examined how CC1-L expression impacts on colon cancer liver metastasis. DESIGN: Murine MC38 transfected with CC1-L were evaluated in vitro for proliferation, migration and invasion, and for in vivo experimental liver metastasis. Using shRNA silencing or pharmacological inhibition, we delineated the role in liver metastasis of Chemokine (C-C motif) Ligand 2 (CCL2) and Signal Transducer and Activator of Transcription 3 (STAT3) downstream of CC1-L. We further assessed the clinical relevance of these findings in a cohort of patients with CRC. RESULTS: MC38-CC1-L-expressing cells exhibited significantly reduced in vivo liver metastasis and displayed decreased CCL2 chemokine secretion and reduced STAT3 activity. Down-modulation of CCL2 expression and pharmacological inhibition of STAT3 activity in MC38 cells led to reduced cell invasion capacity and decreased liver metastasis. The clinical relevance of our findings is illustrated by the fact that high CC1 expression in patients with CRC combined with some inflammation-regulated and STAT3-regulated genes correlate with improved 10-year survival. CONCLUSIONS: CC1-L regulates inflammation and STAT3 signalling and contributes to the maintenance of a less-invasive CRC metastatic phenotype of poorly differentiated carcinomas.


Asunto(s)
Antígenos CD/fisiología , Moléculas de Adhesión Celular/fisiología , Neoplasias del Colon/etiología , Neoplasias del Colon/patología , Animales , Diferenciación Celular , Neoplasias Colorrectales/patología , Femenino , Humanos , Neoplasias Hepáticas/secundario , Masculino , Ratones , Ratones Endogámicos C57BL , Persona de Mediana Edad , Isoformas de Proteínas/fisiología , Células Tumorales Cultivadas
20.
Chembiochem ; 17(8): 644-5, 2016 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-27027879

RESUMEN

This is the first of a two-part Editorial by the Guest Editors of the ChemBioChem and ChemMedChem joint Special Issue on Protein-Protein Interactions. Part 2 can be accessed via http://dx.doi.org/10.1002/cmdc.201600158; the complete issue can be viewed here: bit.ly/cbcVIppi.


Asunto(s)
Proteínas/química , Descubrimiento de Drogas , Humanos , Ligandos , Péptidos/química , Péptidos/farmacología , Unión Proteica , Proteínas/antagonistas & inhibidores , Proteínas/metabolismo , Bibliotecas de Moléculas Pequeñas/química , Bibliotecas de Moléculas Pequeñas/farmacología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA