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Cruz A, Núñez-Montenegro A, Mateus P, Delgado R. Monitoring inorganic pyrophosphatase activity with the fluorescent dizinc(ii) complex of a macrocycle bearing one dansylamidoethyl antenna. Dalton Trans 2020; 49:9487-9494. [PMID: 32608414 DOI: 10.1039/d0dt01673j] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The dizinc(ii) complexes of L were used for the recognition of anions by fluorescence spectroscopy (L is a heteroditopic hexaazamacrocycle with two diethylenetriamine coordination heads with 2-methylpyridyl and dansylamido ethyl arms, and m-xylyl spacers). The protonation of L and stability constants of its zinc(ii) complexes were determined in aqueous solution, at 298.2 ± 0.1 K and I = 0.10 ± 0.01 M in KNO3. At a 2 : 1 Zn2+/L ratio, the dinuclear complexes clearly dominate. The ligand alone does not display fluorescence changes upon increasing the pH value, but in the presence of Zn2+ the emission reaches a maximum at pH ≅ 7.5, at which 95% of the ligand is in the dinuclear complex form. The emission appears concomitantly with the [Zn2H-1L]3+ species formation, which supports that the latter complex corresponds to the metal-promoted deprotonation of dansylamide NH. The [Zn2H-1L]3+ complexes were used for the recognition of phosphate and polyphosphate anions in aqueous solution buffered at pH 7.5 with 2 mM PIPPS, at 298.2 K. The binding of anions causes a decrease of the emission. The association constant determination revealed that HPPi3- is the strongest bound anion (log Kapp = 5.57), followed by HATP3- (two times weaker), and the remaining anions show lower binding constants, with HPO42- having the weakest uptake by the receptor. The observed selectivity of the [Zn2H-1L]3+ receptor for PPi in relation to HPO42-, and the fact that the formation of the [Zn2H-1L]3+ complex is not disturbed by the presence of Mg2+, allowed monitoring of the PPi hydrolysis by using inorganic pyrophosphatase in real-time.
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Affiliation(s)
- Ana Cruz
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal.
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Letra‐Vilela R, Cardoso B, Silva‐Almeida C, Maia Rocha A, Murtinheira F, Branco‐Santos J, Rodriguez C, Martin V, Santa‐Marta M, Herrera F. Can asymmetric post-translational modifications regulate the behavior of STAT3 homodimers? FASEB Bioadv 2020; 2:116-125. [PMID: 32123861 PMCID: PMC7003655 DOI: 10.1096/fba.2019-00049] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 06/14/2019] [Accepted: 12/10/2019] [Indexed: 01/16/2023] Open
Abstract
Signal transducer and activator of transcription 3 (STAT3) is a ubiquitous and pleiotropic transcription factor that plays essential roles in normal development, immunity, response to tissue damage and cancer. We have developed a Venus-STAT3 bimolecular fluorescence complementation assay that allows the visualization and study of STAT3 dimerization and protein-protein interactions in living cells. Inactivating mutations on residues susceptible to post-translational modifications (PTMs) (K49R, K140R, K685R, Y705F and S727A) changed significantly the intracellular distribution of unstimulated STAT3 dimers when the dimers were formed by STAT3 molecules that carried different mutations (ie they were "asymmetric"). Some of these asymmetric dimers changed the proliferation rate of HeLa cells. Our results indicate that asymmetric PTMs on STAT3 dimers could constitute a new level of regulation of STAT3 signaling. We put forward these observations as a working hypothesis, since confirming the existence of asymmetric STAT3 homodimers in nature is extremely difficult, and our own experimental setup has technical limitations that we discuss. However, if our hypothesis is confirmed, its conceptual implications go far beyond STAT3, and could advance our understanding and control of signaling pathways.
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Affiliation(s)
- Ricardo Letra‐Vilela
- Cell Structure and Dynamics LaboratoryInstituto de Tecnologia Quimica e Biologica (ITQB‐NOVA)Universidade Nova de LisboaOeirasPortugal
- Cell Structure and Dynamics LaboratoryFaculdade de CiênciasUniversidade de LisboaLisbonPortugal
| | - Beatriz Cardoso
- Cell Structure and Dynamics LaboratoryInstituto de Tecnologia Quimica e Biologica (ITQB‐NOVA)Universidade Nova de LisboaOeirasPortugal
| | - Catarina Silva‐Almeida
- Cell Structure and Dynamics LaboratoryInstituto de Tecnologia Quimica e Biologica (ITQB‐NOVA)Universidade Nova de LisboaOeirasPortugal
| | - Ana Maia Rocha
- Cell Structure and Dynamics LaboratoryInstituto de Tecnologia Quimica e Biologica (ITQB‐NOVA)Universidade Nova de LisboaOeirasPortugal
| | - Fernanda Murtinheira
- Cell Structure and Dynamics LaboratoryInstituto de Tecnologia Quimica e Biologica (ITQB‐NOVA)Universidade Nova de LisboaOeirasPortugal
- Cell Structure and Dynamics LaboratoryFaculdade de CiênciasUniversidade de LisboaLisbonPortugal
| | - Joana Branco‐Santos
- Cell Structure and Dynamics LaboratoryInstituto de Tecnologia Quimica e Biologica (ITQB‐NOVA)Universidade Nova de LisboaOeirasPortugal
| | - Carmen Rodriguez
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA) and Departamento de Morfología y Biología CelularFacultad de MedicinaUniversity of OviedoOviedoSpain
| | - Vanesa Martin
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA) and Departamento de Morfología y Biología CelularFacultad de MedicinaUniversity of OviedoOviedoSpain
| | - Mariana Santa‐Marta
- Cell Structure and Dynamics LaboratoryInstituto de Tecnologia Quimica e Biologica (ITQB‐NOVA)Universidade Nova de LisboaOeirasPortugal
| | - Federico Herrera
- Cell Structure and Dynamics LaboratoryInstituto de Tecnologia Quimica e Biologica (ITQB‐NOVA)Universidade Nova de LisboaOeirasPortugal
- Cell Structure and Dynamics LaboratoryFaculdade de CiênciasUniversidade de LisboaLisbonPortugal
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Mateus P, Delgado R. Zinc(ii) and copper(ii) complexes as tools to monitor/inhibit protein phosphorylation events. Dalton Trans 2020; 49:17076-17092. [DOI: 10.1039/d0dt03503c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A perspective on the advance of copper(ii) and zinc(ii) complexes of varied ligand architectures as binders of phosphorylated peptides/proteins and as sensors of phosphorylation reactions is presented.
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Affiliation(s)
- Pedro Mateus
- Laboratorio Associado para a Química Verde (LAQV)
- Rede de Química e Tecnologia (REQUIMTE)
- Departamento de Química
- Faculdade de Ciências e Tecnologia
- Universidade Nova de Lisboa
| | - Rita Delgado
- Instituto de Tecnologia Química e Biológica António Xavier
- Universidade Nova de Lisboa (ITQB NOVA)
- 2780-157 Oeiras
- Portugal
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Mesquita LM, Mateus P, Fernandes RDV, Iranzo O, André V, Tiago de Oliveira F, Platas-Iglesias C, Delgado R. Recognition of phosphopeptides by a dinuclear copper(ii) macrocyclic complex in a water : methanol 50 : 50 v/v solution. Dalton Trans 2018; 46:9549-9564. [PMID: 28702582 DOI: 10.1039/c7dt01724c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new triethylbenzene-derived tetraazamacrocycle containing pyridyl spacers, L, was prepared and its dinuclear copper(ii) complex was used as a receptor for the recognition of phosphorylated peptides in aqueous solution. A detailed study of the acid-base behaviour of L and its copper(ii) complexation properties as well as of the cascade species with phosphorylated anions including two peptidic substrates was carried out in a H2O/MeOH (50 : 50 v/v) solution using different techniques, such as potentiometry, X-band EPR and DFT calculations. The association constants of the dinuclear receptor with the phosphorylated peptides and other anionic species revealed a clear preference towards phenylic phosphorylated substrates, with values ranging 3.96-5.35 log units. Single-crystal X-ray diffraction determination of the dicopper(ii) complex of L showed the copper centres at a distance of 5.812(1) Å from one another, with the phosphate group of the PhPO42- substrate well accommodated between them. X-band EPR studies indicated a similar structure for this cascade complex and for the other cascade complexes with the phosphorylated anions studied. DFT studies of the [Cu2L(μ-OH)]3+ complex revealed a different conformation of the ligand that brings the two copper centres at a very short distance of 3.94 Å aided by the presence of a bridging hydroxide anion that provides a CuOCu angle of 167.3°. This complex is EPR silent, in line with the singlet ground state obtained using CASSCF(2,2) calculations and DFT calculations with the broken-symmetry approach. This species coexists in solution with a complex in a different conformation, and having a CuCu distance of 6.63 Å, in lower percentage.
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Affiliation(s)
- Lígia M Mesquita
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal.
| | - Pedro Mateus
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal.
| | - Rui D V Fernandes
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal.
| | - Olga Iranzo
- Aix Marseille Univ., CNRS, Centrale Marseille, iSm2, Marseille, France
| | - Vânia André
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
| | - Filipe Tiago de Oliveira
- Laboratório de Instrumentação, Engenharia Biomédica e Física da Radiação (LIBPhys-UNL), Departamento de Física, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, Monte de Caparica, 2829-516 Caparica, Portugal
| | - Carlos Platas-Iglesias
- Centro de Investigaciones Científicas Avanzadas (CICA) and Departamento de Química, Facultade de Ciencias, Universidade da Coruña, Campus da Zapateira-Rúa da Fraga 10, 15008 A Coruña, Spain
| | - Rita Delgado
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal.
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Cryptotanshinone inhibits human glioma cell proliferation in vitro and in vivo through SHP-2-dependent inhibition of STAT3 activation. Cell Death Dis 2017; 8:e2767. [PMID: 28492557 PMCID: PMC5520699 DOI: 10.1038/cddis.2017.174] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/16/2017] [Accepted: 03/20/2017] [Indexed: 12/22/2022]
Abstract
Malignant gliomas (MGs) are one of the most common primary brain cancers in adults with a high mortality rate and relapse rate. Thus, finding better effective approaches to treat MGs has become very urgent. Here, we studied the effects of cryptotanshinone (CTS) on MGs in vitro and in vivo, and explored the underlying mechanisms. Effects of CTS in vitro on cell proliferation, cycle, migration and invasion were evaluated. The activation of JAK/STATs signaling was detected by western blot and immunofluorescenc staining. SHP-2 inhibitor or SiRNA were used to determine the involvement of SHP-2. The in vivo anti-MGs activity of CTS was studied with nude mice bearing intracerebral U87 xenografts. Our results revealed that CTS significantly inhibited the proliferation of MGs in vitro via inhibiting STAT3 signal pathway. The cell cycle was arrested at G0/G1 phase. Although CTS did not change the expression of total SHP-2 protein, the tyrosine phosphatase activity of SHP-2 protein was increased by CTS treatment in a dose-dependent manner in vivo and in vitro. SHP-2 inhibitor or SiRNA could reverse the inhibitory effect of CTS on phosphorylation of STAT3 Tyr705. In vivo study also showed that CTS inhibited the intracranial tumor growth and extended survival of nude mice bearing intracerebral U87 xenografts, confirming an inhibitory effect of CTS on MGs. Our results indicated CTS may be a potential therapeutic agent for MGs. The inhibitory action of CTS is largely attributed to the inhibition of STAT3 Tyr705 phosphorylation with a novel mechanism of upregulating the tyrosine phosphatase activity of SHP-2 protein.
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