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2.
Nat Mater ; 19(7): 797-806, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32066931

RESUMO

Defining the interplay between the genetic events and microenvironmental contexts necessary to initiate tumorigenesis in normal cells is a central endeavour in cancer biology. We found that receptor tyrosine kinase (RTK)-Ras oncogenes reprogram normal, freshly explanted primary mouse and human cells into tumour precursors, in a process requiring increased force transmission between oncogene-expressing cells and their surrounding extracellular matrix. Microenvironments approximating the normal softness of healthy tissues, or blunting cellular mechanotransduction, prevent oncogene-mediated cell reprogramming and tumour emergence. However, RTK-Ras oncogenes empower a disproportional cellular response to the mechanical properties of the cell's environment, such that when cells experience even subtle supra-physiological extracellular-matrix rigidity they are converted into tumour-initiating cells. These regulations rely on YAP/TAZ mechanotransduction, and YAP/TAZ target genes account for a large fraction of the transcriptional responses downstream of oncogenic signalling. This work lays the groundwork for exploiting oncogenic mechanosignalling as a vulnerability at the onset of tumorigenesis, including tumour prevention strategies.

3.
Proc Natl Acad Sci U S A ; 116(36): 17848-17857, 2019 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-31416916

RESUMO

Autophagy, besides ensuring energy metabolism and organelle renewal, is crucial for the biology of adult normal and cancer stem cells. However, it remains incompletely understood how autophagy connects to stemness factors and the nature of the microenvironmental signals that pattern autophagy in different cell types. Here we advance in these directions by reporting that YAP/TAZ transcriptionally control autophagy, being critical for autophagosomal degradation into autolysosomes. YAP/TAZ are downstream effectors of cellular mechanotransduction and indeed we found that cell mechanics, dictated by the physical property of the ECM and cytoskeletal tension, profoundly impact on autophagic flux in a YAP/TAZ-mediated manner. Functionally, by using pancreatic and mammary organoid cultures, we found that YAP/TAZ-regulated autophagy is essential in normal cells for YAP/TAZ-mediated dedifferentiation and acquisition of self-renewing properties. In tumor cells, the YAP/TAZ-autophagy connection is key to sustain transformed traits and for acquisition of a cancer stem cell state by otherwise more benign cells. Mechanistically, YAP/TAZ promote autophagic flux by directly promoting the expression of Armus, a RAB7-GAP required for autophagosome turnover and whose add-back rescues autophagy in YAP/TAZ-depleted cells. These findings expand the influence of YAP/TAZ mechanotransduction to the control of autophagy and, vice versa, the role of autophagy in YAP/TAZ biology, and suggest a mechanism to coordinate transcriptional rewiring with cytoplasmic restructuring during cell reprogramming.


Assuntos
Autofagia , Proteínas de Ciclo Celular/metabolismo , Plasticidade Celular , Mecanotransdução Celular , Fatores de Transcrição/metabolismo , Adaptação Fisiológica , Animais , Autofagossomos , Humanos , Lisossomos/metabolismo , Ligação Proteica , Proteólise
4.
Adv Sci (Weinh) ; 5(12): 1800937, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30581702

RESUMO

Shaping ceramic materials at the nanoscale in 3D is a phenomenal engineering challenge, that can offer new opportunities in a number of industrial applications, including metamaterials, nano-electromechanical systems, photonic crystals, and damage-tolerant lightweight materials. 3D fabrication of sub-micrometer ceramic structures can be performed by two-photon laser writing of a preceramic polymer. However, polymer conversion to a fully ceramic material has proven so far unfeasible, due to lack of suitable precursors, printing complexity, and high shrinkage during ceramic conversion. Here, it is shown that this goal can be achieved through an appropriate engineering of both the material and the printing process, enabling the fabrication of preceramic 3D shapes and their transformation into dense and crack-free SiOC ceramic components with highly complex, 3D sub-micrometer architectures. This method allows for the manufacturing of components with any 3D specific geometry with fine details down to 450 nm, rapidly printing structures up to 100 µm in height that can be converted into ceramic objects possessing sub-micrometer features, offering unprecedented opportunities in different application fields.

5.
Nature ; 563(7730): 265-269, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30401838

RESUMO

Inactivation of ARID1A and other components of the nuclear SWI/SNF protein complex occurs at very high frequencies in a variety of human malignancies, suggesting a widespread role for the SWI/SNF complex in tumour suppression1. However, the underlying mechanisms remain poorly understood. Here we show that ARID1A-containing SWI/SNF complex (ARID1A-SWI/SNF) operates as an inhibitor of the pro-oncogenic transcriptional coactivators YAP and TAZ2. Using a combination of gain- and loss-of-function approaches in several cellular contexts, we show that YAP/TAZ are necessary to induce the effects of the inactivation of the SWI/SNF complex, such as cell proliferation, acquisition of stem cell-like traits and liver tumorigenesis. We found that YAP/TAZ form a complex with SWI/SNF; this interaction is mediated by ARID1A and is alternative to the association of YAP/TAZ with the DNA-binding platform TEAD. Cellular mechanotransduction regulates the association between ARID1A-SWI/SNF and YAP/TAZ. The inhibitory interaction of ARID1A-SWI/SNF and YAP/TAZ is predominant in cells that experience low mechanical signalling, in which loss of ARID1A rescues the association between YAP/TAZ and TEAD. At high mechanical stress, nuclear F-actin binds to ARID1A-SWI/SNF, thereby preventing the formation of the ARID1A-SWI/SNF-YAP/TAZ complex, in favour of an association between TEAD and YAP/TAZ. We propose that a dual requirement must be met to fully enable the YAP/TAZ responses: promotion of nuclear accumulation of YAP/TAZ, for example, by loss of Hippo signalling, and inhibition of ARID1A-SWI/SNF, which can occur either through genetic inactivation or because of increased cell mechanics. This study offers a molecular framework in which mechanical signals that emerge at the tissue level together with genetic lesions activate YAP/TAZ to induce cell plasticity and tumorigenesis.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/antagonistas & inibidores , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas de Ligação a DNA/metabolismo , Mecanotransdução Celular , Complexos Multiproteicos/metabolismo , Proteínas Nucleares/antagonistas & inibidores , Proteínas Nucleares/metabolismo , Fatores de Transcrição/antagonistas & inibidores , Actinas/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Carcinogênese/genética , Proteínas de Ciclo Celular , Linhagem Celular , Núcleo Celular/metabolismo , Proliferação de Células , Proteínas de Ligação a DNA/deficiência , Proteínas de Ligação a DNA/genética , Feminino , Humanos , Masculino , Camundongos , Complexos Multiproteicos/química , Complexos Multiproteicos/deficiência , Complexos Multiproteicos/genética , Proteínas Nucleares/genética , Ligação Proteica , Proteínas Serina-Treonina Quinases/metabolismo , Estresse Mecânico , Fatores de Transcrição/metabolismo , Via de Sinalização Wnt
6.
Nat Mater ; 17(12): 1063-1075, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30374202

RESUMO

Mechanical signals are increasingly recognized as overarching regulators of cell behaviour, controlling stemness, organoid biology, tissue development and regeneration. Moreover, aberrant mechanotransduction is a driver of disease, including cancer, fibrosis and cardiovascular defects. A central question remains how cells compute a host of biomechanical signals into meaningful biological behaviours. Biomaterials and microfabrication technologies are essential to address this issue. Here we review a large body of evidence that connects diverse biomaterial-based systems to the functions of YAP/TAZ, two highly related mechanosensitive transcriptional regulators. YAP/TAZ orchestrate the response to a suite of engineered microenviroments, emerging as a universal control system for cells in two and three dimensions, in static or dynamic fashions, over a range of elastic and viscoelastic stimuli, from solid to fluid states. This approach may guide the rational design of technological and material-based platforms with dramatically improved functionalities and inform the generation of new biomaterials for regenerative medicine applications.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Materiais Biocompatíveis/farmacologia , Engenharia Celular , Microambiente Celular , Fatores de Transcrição/metabolismo , Animais , Microambiente Celular/efeitos dos fármacos , Humanos , Mecanotransdução Celular/efeitos dos fármacos
7.
Nanotechnology ; 29(36): 36LT03, 2018 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-29901453

RESUMO

We report on the near edge x-ray absorption fine structure (NEXAFS) spectroscopy of hybrid organic-inorganic resists. These materials are nonchemically amplified systems based on Si, Zr, and Ti oxides, synthesized from organically modified precursors and transition metal alkoxides by a sol-gel route and designed for ultraviolet, extreme ultraviolet (EUV) and electron beam lithography. The experiments were conducted using a scanning transmission x-ray microscope (STXM) which combines high spatial-resolution microscopy and NEXAFS spectroscopy. The absorption spectra were collected in the proximity of the carbon edge (∼290 eV) before and after in situ exposure, enabling the measurement of a significant photo-induced degradation of the organic group (phenyl or methyl methacrylate, respectively), the degree of which depends on the configuration of the ligand. Photo-induced degradation was more efficient in the resist synthesized with pendant phenyl substituents than it was in the case of systems based on bridging phenyl groups. The degradation of the methyl methacrylate group was relatively efficient, with about half of the initial ligands dissociated upon exposure. Our data reveal that such dissociation can produce different outcomes, depending on the structural configuration. While all the organic groups were expected to detach and desorb from the resist in their entirety, a sizeable amount of them remained and formed undesired byproducts such as alkene chains. In the framework of the materials synthesis and engineering through specific building blocks, these results provide a deeper insight into the photochemistry of resists, in particular for EUV lithography.

8.
Acta Biomater ; 55: 373-384, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28351679

RESUMO

Hydrogels are widely used as matrices for cell growth due to the their tuneable chemical and physical properties, which mimic the extracellular matrix of natural tissue. The microfabrication of hydrogels into arbitrarily complex 3D structures is becoming essential for numerous biological applications, and in particular for investigating the correlation between cell shape and cell function in a 3D environment. Micrometric and sub-micrometric resolution hydrogel scaffolds are required to deeply investigate molecular mechanisms behind cell-matrix interaction and downstream cellular processes. We report the design and development of high resolution 3D gelatin hydrogel woodpile structures by two-photon crosslinking. Hydrated structures of lateral linewidth down to 0.5µm, lateral and axial resolution down to a few µm are demonstrated. According to the processing parameters, different degrees of polymerization are obtained, resulting in hydrated scaffolds of variable swelling and deformation. The 3D hydrogels are biocompatible and promote cell adhesion and migration. Interestingly, according to the polymerization degree, 3D hydrogel woodpile structures show variable extent of cell adhesion and invasion. Human BJ cell lines show capability of deforming 3D micrometric resolved hydrogel structures. STATEMENT OF SIGNIFICANCE: The design and development of high resolution 3D gelatin hydrogel woodpile structures by two-photon crosslinking is reported. Significantly, topological and mechanical conditions of polymerized gelatin structures were suitable for cell accommodation in the volume of the woodpiles, leading to a cell density per unit area comparable to the bare substrate. The fabricated structures, presenting micrometric features of high resolution, are actively deformed by cells, both in terms of cell invasion within rods and of cell attachment in-between contiguous woodpiles. Possible biological targets for this 3D approach are customized 3D tissue models, or studies of cell adhesion, deformation and migration.


Assuntos
Matriz Extracelular/química , Fibroblastos , Hidrogéis/química , Microscopia de Fluorescência por Excitação Multifotônica , Tecidos Suporte/química , Linhagem Celular , Fibroblastos/citologia , Fibroblastos/metabolismo , Humanos
9.
Macromol Rapid Commun ; 38(1)2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27859820

RESUMO

In this work, an engineered hydrogel system with a 2D and 3D tunable cross-linking degree is presented. A precise chemical design by the introduction of cross-linkable units, having reaction orthogonality, allows to control the network formation both in time and space and to selectively alter the hydrogel physical properties. Hydrogel chemistry has been tailored in order to produce spatially controlled stiffness changes and drive cell morphology through mechanical cues. Elastic modulus rises by more than double after photocross-linking, as shown by atomic force microscopy measurements. Biological response is also analyzed and stiffness-dependent cell spreading and proliferation are verified. Different pattern geometries are successfully realized by UV lithography, allowing 2D cross-linking modulation. Furthermore, 3D mechanical tuning at micro- and submicrometer scale by two-photon polymerization makes this system a biologically relevant matrix to study cell functions and tissue development.


Assuntos
Reagentes para Ligações Cruzadas/química , Hidrogel de Polietilenoglicol-Dimetacrilato/química , Tamanho da Partícula , Polimerização , Propriedades de Superfície
10.
Mater Sci Eng C Mater Biol Appl ; 59: 585-593, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26652411

RESUMO

Mesoporous silica particles prepared through a simplified Stöber method and low temperature solvent promoted surfactant removal are evaluated as dissolution enhancers for poorly soluble compounds, using a powerful anticancer agent belonging to pyrroloquinolinones as a model for anticancer oral therapy, and anti-inflammatory ibuprofen as a reference compound. Mesoporous powders composed of either pure silica or silica modified with aminopropyl residues are produced. The influence of material composition and drug chemical properties on drug loading capability and dissolution enhancement are studied. The two types of particles display similar size, surface area, porosity, erodibility, drug loading capability and stability. An up to 50% w/w drug loading is reached, showing correlation between drug concentration in adsorption medium and content in the final powder. Upon immersion in simulating body fluids, immediate drug dissolution occurred, allowing acceptor solutions to reach concentrations equal to or greater than drug saturation limits. The matrix composition influenced drug solution maximal concentration, complementing the dissolution enhancement generated by a mesoporous structure. This effect was found to depend on both matrix and drug chemical properties allowing us to hypothesise general prediction behaviour rules.


Assuntos
Antineoplásicos/química , Portadores de Fármacos/química , Microesferas , Nanopartículas/química , Dióxido de Silício/química , Estabilidade de Medicamentos , Transição de Fase
11.
Adv Mater ; 28(2): 370-6, 2016 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-26545292

RESUMO

The first example of the fabrication of complex 3D polymer-derived-ceramic structures is presented with micrometer-scale features by a 3D additive manufacturing (AM) technology, starting with a photosensitive preceramic precursor. Dense and crack-free silicon-oxycarbide-based microparts with features down to 200 µm are obtained after pyrolysis at 1000 °C in a nitrogen atmosphere.

12.
ACS Appl Mater Interfaces ; 7(24): 13280-8, 2015 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-26017394

RESUMO

DNA biochip assays often require immobilization of bioactive molecules on solid surfaces. A simple biofunctionalization protocol and precise spatial binding represent the two major challenges in order to obtain localized region specific biopatterns into lab-on-a-chip (LOC) systems. In this work, a simple strategy to anchor oligonucleotides on microstructured areas and integrate the biomolecules patterns within microfluidic channels is reported. A photosensitive ZrO2 system is proposed as an advanced platform and versatile interface for specific positioning and oriented immobilization of phosphorylated DNA. ZrO2 sol-gel structures were easily produced on fused silica by direct UV lithography, allowing a simple and fast patterning process with different geometries. A thermal treatment at 800 °C was performed to crystallize the structures and maximize the affinity of DNA to ZrO2. Fluorescent DNA strands were selectively immobilized on the crystalline patterns inside polydimethylsiloxane (PDMS) microchannels, allowing high specificity and rapid hybridization kinetics. Hybridization tests confirmed the correct probe anchoring and the bioactivity retention, while denaturation experiments demonstrated the possibility of regenerating the surface.


Assuntos
Ácidos Nucleicos Imobilizados/química , Técnicas Analíticas Microfluídicas/instrumentação , Técnicas Analíticas Microfluídicas/métodos , Zircônio/química , Nanotecnologia , Propriedades de Superfície
13.
ACS Appl Mater Interfaces ; 7(13): 7273-81, 2015 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-25756304

RESUMO

An industrially feasible process for the fast mass-production of molded polymeric micro-patterned substrates is here presented. Microstructured polystyrene (PS) surfaces were obtained through micro injection molding (µIM) technique on directly patterned stamps realized with a new zirconia-based hybrid spin-on system able to withstand 300 cycles at 90 °C. The use of directly patterned stamps entails a great advantage on the overall manufacturing process as it allows a fast, flexible, and simple one-step process with respect to the use of milling, laser machining, electroforming techniques, or conventional lithographic processes for stamp fabrication. Among the different obtainable geometries, we focused our attention on PS replicas reporting 2, 3, and 4 µm diameter pillars with 8, 9, 10 µm center-to-center distance, respectively. This enabled us to study the effect of the substrate topography on human mesenchymal stem cells behavior without any osteogenic growth factors. Our data show that microtopography affected cell behavior. In particular, calcium deposition and osteocalcin expression enhanced as diameter and interpillar distance size increases, and the 4-10 surface was the most effective to induce osteogenic differentiation.


Assuntos
Regeneração Óssea/fisiologia , Células-Tronco Mesenquimais/citologia , Impressão Molecular/métodos , Osteoblastos/citologia , Poliestirenos/química , Impressão Tridimensional , Diferenciação Celular/fisiologia , Células Cultivadas , Humanos , Teste de Materiais , Células-Tronco Mesenquimais/fisiologia , Osteoblastos/fisiologia , Osteogênese/fisiologia , Propriedades de Superfície , Engenharia Tecidual/instrumentação , Engenharia Tecidual/métodos , Tecidos Suporte
14.
ACS Appl Mater Interfaces ; 6(10): 7773-81, 2014 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-24750118

RESUMO

We report the achievement of sensitive gas detection using periodic silver nanoprisms fabricated by a simple and low-cost lithographic technique. The presence of sharp tips combined with the periodic arrangement of the nanoprisms allowed the excitement of isolated and interacting localized surface plasmon resonances. Specific sensing capabilities with respect to aromatic hydrocarbons were achieved when the metal nanoprism arrays were coupled in the near field with functional hybrid films, providing a real-time, label-free, and reversible methodology. Ultra-high-vacuum temperature-programmed desorption measurements demonstrated an interaction energy between the sensitive film and analytes in the range of 55-71 kJ/mol. The far-field optical properties and the detection sensitivity of the sensors, modeled using a finite element method, were correlated to experimental data from gas sensing tests. An absorbance variation of 1.2% could be observed and associated with a theoretical increase in the functional film refractive index of ∼0.001, as a consequence to the interaction with 30 ppm xylene. The possibility of detecting such a small variation in the refractive index suggests the highly promising sensing capabilities of the presented technique.

15.
Adv Mater ; 25(43): 6261-5, 2013 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-23913661

RESUMO

A new spin-on alumina-based resist exhibits excellent performance in terms of both achievable lateral resolution and etch resistance in fluorine-based non-cryo-cooled dry etching processes. The resist has selectivity greater than 100:1 with respect to the underlying silicon during the etching process, patternability with various lithographic tools (UV, X-rays, electron beam, and nanoimprint lithography), and positive and negative tone behavior depending only on the developer chemistry.

16.
Opt Express ; 21(11): 12996-3004, 2013 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-23736553

RESUMO

Active gratings have been used to realize a grazing-incidence double-grating monochromator for the spectral selection of ultrashort pulses while preserving the temporal duration by compensating for the pulse-front tilt. The active grating consists of a bimorph deformable mirror on the top of which a diffraction grating with laminar profile is realized by UV lithography. The time-delay compensated configuration has been tested with ultrashort pulses at 800 nm. The feasibility of this configuration for the extreme-ultraviolet spectral region has been demonstrated by ray tracing studies.

17.
Nanoscale ; 3(10): 4109-13, 2011 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-21912805

RESUMO

We report a facile production of an up-converted surface-emitting DFB laser, performed by exploiting the versatility of sol-gel chemistry, the intriguing properties of well designed graded CdSe-CdS-Cd(0.5)Zn(0.5)S-ZnS colloidal quantum dots, and the scalability of nanoimprinting. Our laser prototype operates in the visible region following efficient optical pumping by either direct one-photon excitation or through the up-conversion of near infrared (NIR) light. By achieving cavity mode Q-factors in excess of 650 and retaining high lasing stabilities in air, this work highlights the feasibility of creating integrated lasing devices through solution based methods.


Assuntos
Lasers , Pontos Quânticos , Compostos de Cádmio/química , Géis/química , Compostos de Selênio/química , Sulfetos/química , Compostos de Zinco/química
18.
J Nanosci Nanotechnol ; 11(1): 195-9, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21446426

RESUMO

Hybrid SiO2-TiO2 films are prepared starting from tetraisopropoxy titanate and 3-glycidoxipropyltrimethoxysilane, using the sol-gel process. During the sol synthesis titania clusters grow, conferring to the samples a photocatalytic activity. In this paper we exploit this property for the fabrication of surface-relief gratings. The realized structures are characterized by SEM, AFM and profilometric measurements, while the presence of titania clusters is confirmed by TEM analyses.

19.
ACS Appl Mater Interfaces ; 2(5): 1294-8, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20392071

RESUMO

The photocatalytic activity of TiO(2) films synthesized via the sol-gel process has been measured as a function of UV irradiation time and substrate temperature. Fourier-transform infrared spectroscopy has been used to address the chemical changes in stearic acid and block copolymer Pluronic F127 films deposited on the photocatalytic surface. When the temperature of the photocatalytic substrate was raised above 50 degrees C, the removal of stearic acid from the surface was strongly affected by a process involving evaporation, whereas Pluronic F127 revealed a superior stability. Our study shows that heat enhances the photocatalytic activity, suggesting the importance of an accurate temperature control in photocatalytic efficiency measurements.


Assuntos
Membranas Artificiais , Fotoquímica/métodos , Titânio/química , Titânio/efeitos da radiação , Catálise , Teste de Materiais , Transição de Fase , Temperatura , Raios Ultravioleta
20.
J Nanosci Nanotechnol ; 9(3): 1858-64, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19435050

RESUMO

Two different sol-gel hybrid organic-inorganic films doped with luminescent CdS or PbS quantum dots (QDs) have been successfully synthesized and patterned using nanolithographic techniques. The feasibility of applying X-ray lithography and RIE to pattern hybrid materials doped with highly luminescent nanoparticles has been demonstrated for GPTMS-GeO2 (G-GeO2) and MPTMS-ZrO2 (M-ZrO2) hybrids obtained form 3-glycidoxypropyltrymethoxysilane (GPTMS), methacryloxy-propil-trimethoxysilane (MPTMS), germanium ethoxide and zirconium propoxide. Semiconductor doped film have been obtained by mixing ZrO2-SiO2 or GeO2-SiO2 sol-gel hybrid organic-inorganic matrix solution with CdS or PbS colloidal doping solution to obtain up to 20% molar concentration of QDs inside the films. Patterns consisting of pillars with different aspect ratio have been obtained by X-ray lithography and reactive ion etching (RIE). Structural and optical characterization of films before and after the lithographic process pointed out that both matrices and QDs retain their original properties without been affected by X-rays irradiation and RIE in the conditions here described.

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