E-cadherin regulates cell growth by modulating proliferation-dependent β-catenin transcriptional activity

β-Catenin is essential for E-cadherin–mediated cell adhesion in epithelial cells, but it also forms nuclear complexes with high mobility group transcription factors. Using a mouse mammary epithelial cell system, we have shown previously that conversion of epithelial cells to a fibroblastoid phenotype (epithelial-mesenchymal transition) involves downregulation of E-cadherin and upregulation of β-catenin transcriptional activity. Here, we demonstrate that transient expression of exogenous E-cadherin in both epithelial and fibroblastoid cells arrested cell growth or caused apoptosis, depending on the cellular E-cadherin levels. By expressing E-cadherin subdomains, we show that the growth-suppressive effect of E-cadherin required the presence of its cytoplasmic β-catenin interaction domain and/or correlated strictly with the ability to negatively interfere with β-catenin transcriptional activity. Furthermore, coexpression of β-catenin or lymphoid enhancer binding factor-1 or T cell factor 3 with E-cadherin rescued β-catenin transcriptional activity and counteracted E-cadherin–mediated cell cycle arrest. Stable expression of E-cadherin in fibroblastoid cells decreased β-catenin activity and reduced cell growth. Since proliferating cells had a higher β-catenin activity than G1 phase–arrested or contact-inhibited cells, we conclude that β-catenin transcriptional activity is essential for cell proliferation and can be controlled by E-cadherin in a cell adhesion-independent manner

Rational Strain Engineering in Delafossite Oxides for Highly Efficient Hydrogen Evolution Catalysis in Acidic Media

The rational design of hydrogen evolution reaction (HER) electrocatalysts which are competitive with platinum is an outstanding challenge to make power-to-gas technologies economically viable. Here, we introduce the delafossites PdCrO$_2$, PdCoO$_2$ and PtCoO$_2$ as a new family of electrocatalysts for the HER in acidic media. We show that in PdCoO$_2$ the inherently strained Pd metal sublattice acts as a pseudomorphic template for the growth of a strained (by +2.3%) Pd rich capping layer under reductive conditions. The surface modification continuously improves the electrocatalytic activity by simultaneously increasing the exchange current density j$_0$ from 2 to 5 mA/cm$^2_{geo}$ and by reducing the Tafel slope down to 38 mV/decade, leading to overpotentials $\eta_{10}$ < 15 mV for 10 mA/cm$^2_{geo}$, superior to bulk platinum. The greatly improved activity is attributed to the in-situ stabilization of a $\beta$-palladium hydride phase with drastically enhanced surface catalytic properties with respect to pure or nanostructured palladium. These findings illustrate how operando induced electrodissolution can be used as a top-down design concept for rational surface and property engineering through the strain-stabilized formation of catalytically active phases

The Stacking Faulted Nature of the Narrow Gap Semiconductor Sc2_{2}Si2_{2}Te6_{6}

Crystals of Sc$_{2}$Si$_{2}$Te$_{6}$ have been grown and its crystal, micro- and electronic structures were investigated. The layered character of the title compound exhibits stacking faults that impede a full structural characterization by single crystal X-ray diffraction due to diffuse scattering. Based on high resolution transmission electron micrographs and diffraction patterns, the stacking faulted nature of the real structure of Sc$_{2}$Si$_{2}$Te$_{6}$ has been revealed. Different stacking models were derived from the idealized, faultless structure and the stacking disorder was quantitatively analyzed by Rietveld refinement of powder X-ray diffraction patterns. An energetic comparison of the stacking models by density functional theory is in line with the experimental observations. Further, the bonding situation was investigated by electronic structure calculations. Sc$_{2}$Si$_{2}$Te$_{6}$ is a narrow gap semiconductor with an indirect band gap of 0.65 eV

Lanthanide orthothiophosphates revisited: single-crystal X-ray, Raman, and DFT studies of TmPS4 and YbPS4

The crystal structures of the lanthanide orthothiophosphates LnPS(4) (Ln = lanthanide) have been extensively investigated in the past. Up to now, however, single crystals of two members of this series - TmPS4 and YbPS4 - have not been available. Here, we report a modified synthesis protocol for TmPS4 and YbPS4 yielding single crystals suitable for X-ray diffraction. Both compounds crystallize in the tetragonal space group I4(1)/acd (no. 142) with 16 formula units per unit cell and adopt the SmPS4 parent structure, like most reported lanthanide orthothiophosphates. The structures contain isolated [PS4](3-) tetrahedra and two crystallographically independent Le cations, which form trigonal-dodecahedral [LnS(8)](13-) polyhedra. The lattice parameters for TmPS4 are a =10.598(2), c=18.877(4) angstrom with V=2120.2(6) angstrom(3), and for YbPS4 a=10.577(2), c =18.827(4)angstrom with V= 2106.2(7) angstrom(3). The DFT-calculated electronic band structures indicate semiconducting behavior and reveal indirect band gaps of 2.1-2.2 eV, consistent with the reddish brown color of YbPS4, but underestimating the band gap of pale-yellow TmPS4. The Raman spectra are dominated by [PS4](3-) vibrations as confirmed by DFT-calculated phonon spectra. DTA measurements reveal remarkably high thermal stability compared to other known orthothiophosphate compounds

Synthesis and Characterization of Three New Lithium-Scandium Hexathiohypodiphosphates: Li4-3xScxP2S6(x= 0.358),m-LiScP2S6, andt-LiScP2S6

We report the first examples of lithium rare earth metal hexathiohypodiphosphates(IV). Three new lithium-scandium hexathiohypodiphosphates(IV) were synthesized and characterized. The compounds crystallize in three different structure types, featuring isolated ethane-like [P2S6](4-) hexathiohypodiphosphate(IV) units. Li2.926Sc0.358P2S6 or Li4-3xScxP2S6 (x = 0.358) crystallizes in the space group P31m (no. 162) with a = b = 6.0966(5) angstrom, c = 6.5866(6) angstrom, V = 212.02(4) angstrom(3), and Z = 1. The compound is isostructural to Li2FeP2S6 as well as the Li ion conductor Li4-2xMgxP2S6 (x = 1/3, 2/3). Monoclinic LiScP2S6 was found to be a layered compound with van der Waals gaps. The layers consist of edge sharing octahedra that are occupied by Li, Sc, and P-2 in an alternating fashion. It is isostructural to LiAlP2S6 and crystallizes in the space group C2/c (no. 15) with a = 6.933(1) angstrom, b = 10.754(2) angstrom, c = 11.694(2) angstrom, beta = 94.41(3)degrees, V = 869.3(3) angstrom(3), and Z = 4. Trigonal LiScP2S6 crystallizes in the space group P31c (no. 163) with a = b = 6.363(1) angstrom, c = 12.386(3) angstrom, V = 434.3(2) angstrom(3), and Z = 2, and is isostructural to AgInP2S6 and AgScP2S6. Its structure is closely related to the monoclinic version, except that trigonal LiScP2S6 features disordered [P2/2P6/6S6](4-) units. The new phases were investigated by Raman spectroscopy, thermal analysis, and DFT calculations. We further demonstrate that Li4-3xScxP2S6 shows significantly enhanced Li ion conductivity compared to the parent compound Li4P2S6

New Light on an Old Story: The Crystal Structure of Boron Tetrathiophosphate Revisited

The crystal structure of boron tetrathiophosphate BPS4 was reinvestigated using single-crystal X-ray diffraction. The structure shows unidimensional chains similar to SiS2 as structural motifs. BPS4 crystallizes in the orthorhombic space group Ibam (no. 72), with a = 5.6173(3), b = 8.9929(4), c = 5.2433(3) angstrom and V = 264.87(2) angstrom(3) and is closely related to the orthorhombic high-temperature modification of AlPS4 (ht-AlPS4). The SiS2-like chains are all oriented parallel to the c axis, which explains the needle-like morphology and that the crystals easily cleave to thinner needles under mechanical stress. While ht-AlPS4 shows an ordered Al-P sublattice, the B-P sublattice in BPS4 is substantially disordered. The thermal properties of BPS4 were investigated by DTA measurements and a detailed analysis of the Raman spectrum assisted by quantum mechanical calculations is presented. The crystallographic disorder in BPS4 is the result of inter-chain disorder, whereas local intra-chain ordering of B and P can be concluded from Raman spectroscopy

Growth Factor Receptor Expression in Oropharyngeal Squamous Cell Cancer: Her1–4 and c-Met in Conjunction with the Clinical Features and Human Papillomavirus (p16) Status

Simple Summary Growth factor expression is a negative prognostic factor in head and neck squamous cell carcinoma (HNSCC). Targeted therapy has a limited effect on the treatment of advanced stages due to evolving resistance mechanisms. The aim of this study was to assess the distribution of growth factor receptors in oropharyngeal squamous cell cancer (OPSCC) and evaluate their role in the context of the human papillomavirus status, prognosis and possible relevance for targeted therapy. Tissue microarrays of 78 primary OPSCC, 35 related lymph node metastasis, 6 distant metastasis and 9 recurrent tumors were manufactured to evaluate the expression of human epidermal growth factor receptor (EGFR/erbB/Her)1-4 and c-Met by immunohistochemistry. EGFR and c-Met are relevant negative prognostic factors especially in noxae-induced OPSCC. Thus, dual targeting of EGFR and c-Met could be a promising prospective target in OPSCC treatment. Frequent coexpression of assessed receptors represents a possible intrinsic resistance mechanism in targeted therapy. This study aimed to assess the distribution of growth factor receptors in oropharyngeal squamous cell cancer (OPSCC) and evaluate their role in the context of human papillomavirus (HPV) status, prognosis and potential relevance for targeted therapy. The protein expression of human epidermal growth factor receptor (Her)1-4 and c-Met were retrospectively assessed using semiquantitative immunohistochemistry on tissue microarrays and analyzed for correlations as well as differences in the clinicopathological criteria. Her1-4 and c-met were overexpressed compared to normal mucosa in 46%, 4%, 17%, 27% and 23%, respectively. Interestingly, most receptors were coexpressed. Her1 and c-Met were inversely correlated with p16 (p = 0.04; p = 0.02). Her2 and c-Met were associated with high tobacco consumption (p = 0.016; p = 0.04). High EGFR, Her3, Her4 and c-Met expression were associated with worse overall and disease-free survival (p <= 0.05). Furthermore, EGFR and c-Met expression showed raised hazard ratios of 2.53 (p = 0.02; 95% CI 1.24-5.18) and 2.45 (p = 0.02; 95% CI 1.13-5.35), respectively. Her4 was expressed less in distant metastases than in corresponding primary tumors and was correlated to a higher T category. EGFR and c-Met are relevant negative prognostic factors in OPSCC, independent of known clinicopathological parameters. We suggest dual targeting of EGFR and c-Met as a promising strategy for OPSCC treatment

DeltaEF1 is a transcriptional repressor of E-cadherin and regulates epithelial plasticity in breast cancer cells

Downregulation of E-cadherin is a crucial event for epithelial to mesenchymal transition (EMT) in embryonic development and cancer progression. Using the EpFosER mammary tumour model we show that during EMT, upregulation of the transcriptional regulator deltaEF1 coincided with transcriptional repression of E-cadherin. Ectopic expression of deltaEF1 in epithelial cells was sufficient to downregulate E-cadherin and to induce EMT. Analysis of E-cadherin promoter activity and chromatin immunoprecipitation identified deltaEF1 as direct transcriptional repressor of E-cadherin. In human cancer cells, transcript levels of deltaEF1 correlated directly with the extent of E-cadherin repression and loss of the epithelial phenotype. The protein was enriched in nuclei of human cancer cells and physically associated with the E-cadherin promoter. RNA interference-mediated downregulation of deltaEF1 in cancer cells was sufficient to derepress E-cadherin expression and restore cell to cell adhesion, suggesting that deltaEF1 is a key player in late stage carcinogenesis

Order-Disorder Transition driven Superionic Conduction in the New Plastic Polymorph of Na4P2S6

Sodium thiophophates are promising materials for large-scale energy storage applications benefiting from high ionic conductivities and the-political abundance of the elements. A representative of this class is Na4P2S6, which currently shows two known polymorphs–α and β. This work describes a third polymorph of Na4P2S6, γ, that forms above 580◦C, exhibits fast ion conduction with low activation energy, and is mechanically soft. Based on high-temperature diffraction, pair distribution function analysis, thermal analysis, impedance spectroscopy, and ab initio molecular dynamic calculations, γ-Na4P2S6 is identified to be a plastic crystal, characterized by dynamic orientational disorder of the P2S64– anions on a translationally fixed body centered cubic lattice. The prospect of stabilizing plastic crystals at operating temperatures of solid-state batteries and benefiting from their high ionic conductivities as well as mechanical properties could have a strong impact in the field of solid-state battery chemistry