Dataset Information

Conformation-dependent binding of a Tetrastatin peptide to ?v?3 integrin decreases melanoma progression through FAK/PI3K/Akt pathway inhibition.

ABSTRACT: Tetrastatin, a 230 amino acid sequence from collagen IV, was previously demonstrated to inhibit melanoma progression. In the present paper, we identified the minimal active sequence (QKISRCQVCVKYS: QS-13) that reproduced the anti-tumor effects of whole Tetrastatin in vivo and in vitro on melanoma cell proliferation, migration and invasion. We demonstrated that QS-13 binds to SK-MEL-28 melanoma cells through the ?v?3 integrin using blocking antibody and ?3 integrin subunit siRNAs strategies. Relevant QS-13 conformations were extracted from molecular dynamics simulations and their interactions with ?V?3 integrin were analyzed by docking experiments to determine the binding areas and the QS-13 amino acids crucial for the binding. The in silico results were confirmed by in vitro experiments. Indeed, QS-13 binding to SK-MEL-28 was dependent on the presence of a disulfide-bound as shown by mass spectroscopy and the binding site on ?V?3 was located in close vicinity to the RGD binding site. QS-13 binding inhibits the FAK/PI3K/Akt pathway, a transduction pathway that is largely involved in tumor cell proliferation and migration. Taken together, our results demonstrate that the QS-13 peptide binds ?v?3 integrin in a conformation-dependent manner and is a potent antitumor agent that could target cancer cells through ?V?3.

SUBMITTER: Lambert E

PROVIDER: S-EPMC6026150 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature

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Publications

Conformation-dependent binding of a Tetrastatin peptide to αvβ3 integrin decreases melanoma progression through FAK/PI3K/Akt pathway inhibition.

Lambert Eléonore E Fuselier Eloïse E Ramont Laurent L Brassart Bertrand B Dukic Sylvain S Oudart Jean-Baptiste JB Dupont-Deshorgue Aurélie A Sellier Christèle C Machado Carine C Dauchez Manuel M Monboisse Jean-Claude JC Maquart François-Xavier FX Baud Stéphanie S Brassart-Pasco Sylvie S

Scientific reports 20180629 1

Tetrastatin, a 230 amino acid sequence from collagen IV, was previously demonstrated to inhibit melanoma progression. In the present paper, we identified the minimal active sequence (QKISRCQVCVKYS: QS-13) that reproduced the anti-tumor effects of whole Tetrastatin in vivo and in vitro on melanoma cell proliferation, migration and invasion. We demonstrated that QS-13 binds to SK-MEL-28 melanoma cells through the αvβ3 integrin using blocking antibody and β3 integrin subunit s ...[more]

PMID: 29959360

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Project description:BackgroundIn response to brain injury or inflammation, astrocytes undergo hypertrophy, proliferate, and migrate to the damaged zone. These changes, collectively known as "astrogliosis", initially protect the brain; however, astrogliosis can also cause neuronal dysfunction. Additionally, these astrocytes undergo intracellular changes involving alterations in the expression and localization of many proteins, including αvβ3 integrin. Our previous reports indicate that Thy-1, a neuronal glycoprotein, binds to this integrin inducing Connexin43 (Cx43) hemichannel (HC) opening, ATP release, and astrocyte migration. Despite such insight, important links and molecular events leading to astrogliosis remain to be defined.MethodsUsing bioinformatics approaches, we analyzed different Gene Expression Omnibus datasets to identify changes occurring in reactive astrocytes as compared to astrocytes from the normal mouse brain. In silico analysis was validated by both qRT-PCR and immunoblotting using reactive astrocyte cultures from the normal rat brain treated with TNF and from the brain of a hSOD1G93A transgenic mouse model. We evaluated the phosphorylation of Cx43 serine residue 373 (S373) by AKT and ATP release as a functional assay for HC opening. In vivo experiments were also performed with an AKT inhibitor (AKTi).ResultsThe bioinformatics analysis revealed that genes of the PI3K/AKT signaling pathway were among the most significantly altered in reactive astrocytes. mRNA and protein levels of PI3K, AKT, as well as Cx43, were elevated in reactive astrocytes from normal rats and from hSOD1G93A transgenic mice, as compared to controls. In vitro, reactive astrocytes stimulated with Thy-1 responded by activating AKT, which phosphorylated S373Cx43. Increased pS373Cx43 augmented the release of ATP to the extracellular medium and AKTi inhibited these Thy-1-induced responses. Furthermore, in an in vivo model of inflammation (brain damage), AKTi decreased the levels of astrocyte reactivity markers and S373Cx43 phosphorylation.ConclusionsHere, we identify changes in the PI3K/AKT molecular signaling network and show how they participate in astrogliosis by regulating the HC protein Cx43. Moreover, because HC opening and ATP release are important in astrocyte reactivity, the phosphorylation of Cx43 by AKT and the associated increase in ATP release identify a potential therapeutic window of opportunity to limit the adverse effects of astrogliosis.

Dataset Information

Conformation-dependent binding of a Tetrastatin peptide to ?v?3 integrin decreases melanoma progression through FAK/PI3K/Akt pathway inhibition.

Publications

Conformation-dependent binding of a Tetrastatin peptide to α<sub>v</sub>β<sub>3</sub> integrin decreases melanoma progression through FAK/PI<sub>3</sub>K/Akt pathway inhibition.

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