Knockdown of aberrantly expressed nuclear localized decorin attenuates tumour angiogenesis related mediators in oral cancer progression model in vitro

AbstractBackgroundOral cancer accounts for roughly 3% of cancer cases in the world with about 350,000 newly reported cases annually and a 5-year survival rate of only 50%. Majority of oral cancers are squamous cell carcinomas that originate in the oral mucosal epithelial linings. We have previously shown that in human malignant squamous cells carcinoma (SCC-25) as well as in dysplastic oral keratinocytes (DOK), a small leucine-rich multifunctional proteoglycan decorin is aberrantly expressed and localized in the nucleus where it interacts with nuclear epidermal growth factor receptor (EGFR). Post-transcriptional silencing of nuclear decorin significantly reduced IL-8 and IL8-dependent migration and invasion in these dysplastic and malignant oral epithelia. The objective of this study was to further examine the effects of nuclear decorin silencing on angiogenesis and angiogenesis related mediators in this oral cancer progression cell line model.MethodsWe have used multiplex PCR, western blotting, and in vitro endothelial tube formation assay to study angiogenesis and related pathways in nuclear decorin silenced (stable knockdown) DOK and SCC-25 cells.ResultsNuclear decorin knockdown resulted in significant down regulation of IL-8 expression, however IL-10, and TGF-β expression was not affected in either DOK or SCC25 cells as measured by multiplex RT PCR. IL-8 receptor CXCR 1 and 2 expression was slightly lower in nuclear decorin silenced cells indicating a contributing mechanism in previously shown reduced IL-8 mediated migration and invasion phenotype in these cells. IL-8 is known to induce Matrix metalloproteinase 9 (MMP9) which not only plays a role in tumour migration and invasion but also induces angiogenic switch. We found MMP9 to be significantly reduced in nuclear decorin silenced dysplastic and malignant oral epithelia. Other potent angiogenic mediators, VEGF189 and ANG-1 were either significantly reduced or completely abrogated in these cells. Angiogenesis as measured by endothelial tube-like formations of HUVEC cells was reduced by almost 50 percent when HUVECs were incubated in the presence of conditioned medium form nuclear decorin silenced dysplastic and malignant cell lines as compared to respective controls.ConclusionsTogether these results indicate that aberrantly expressed nuclear localized decorin strongly influences angiogenic potential of dysplastic and malignant oral epithelial cells.Peer Reviewe

A T-cell receptor escape channel allows broad T-cell response to CD1b and membrane phospholipids

CD1 proteins are expressed on dendritic cells, where they display lipid antigens to T-cell receptors (TCRs). Here we describe T-cell autoreactivity towards ubiquitous human membrane phospholipids presented by CD1b. These T-cells discriminate between two major types of lipids, sphingolipids and phospholipids, but were broadly cross-reactive towards diverse phospholipids including phosphatidylcholine, phosphatidylinositol and phosphatidylethanolamine. The crystal structure of a representative TCR bound to CD1b-phosphatidylcholine provides a molecular mechanism for this promiscuous recognition. We observe a lateral escape channel in the TCR, which shunted phospholipid head groups sideways along the CD1b-TCR interface, without contacting the TCR. Instead the TCR recognition site involved the neck region phosphate that is common to all major self-phospholipids but absent in sphingolipids. Whereas prior studies have focused on foreign lipids or rare self-lipids, we define a new molecular mechanism of promiscuous recognition of common self-phospholipids including those that are known targets in human autoimmune disease

Charge ordering in B-site Mo doped Pr0.20Sr0.80Mn1-xMoxO3-delta

The temperature dependent structural, transport and magnetic properties of Pr0.20Sr0.80Mn1-xMoxO3-delta (x - 0.0, 0.02, 0.04 and 0.10) have been studied using low-temperature x-ray and electron diffraction, resistivity and dc magnetization measurements. Unlike the undoped (x = 0) sample, which is cubic at room temperature, the Mo doped samples show phase coexistence of cubic (Pm3m) and tetragonal (I4/ mcm; c/root 2 > a) phases. The Mo doping stabilizes the tetragonal (I4/mcm) phase in the temperature range of 300-330 K. The tetragonality of the sample for x = 0.10 however appears to be of different kind, which further under goes an additional transition from tetragonal to orthorhombic (Fmmm) phase below 200 K. Transmission electron microscopy, employing electron-diffraction and high-resolution microstructural imaging, clearly reveals the occurrence of charge-ordering (CO) for x = 0.04 and 0.10 samples with non-integral modulation along [110] type perovskite direction. The dc magnetization and resistivity data very well correlate with the observed structural and associated CO antiferromagnetic phase transitions. The increased stability of the distorted perovskite phases and the occurrence of CO are found to correlate with the increase in the Mn3+/ Mn4+ ratio as a function of Mo6+ substitution. The possible role of effective B-site cation size in stabilizing the distorted perovskite phase has been discussed in terms of tolerance factor. (C) 2017 Elsevier B.V. All rights reserved

Studies on magnetic field and temperature driven magneto-structural phase transition in La0.5Sr0.5MnO3+delta

The influence of magnetic field on the crystal structure of colossal magnetoresistance (CMR) material La0.5Sr0.5MnO3+delta has been investigated. Low temperature high-magnetic field powder X-ray diffraction (XRD) measurements were carried out on La0.5Sr0.5MnO3+delta in temperature range from 4.2 to 300 K and magnetic field range from 0 to 8 T. A first order structural phase transition from tetragonal I4/mcm to orthorhombic Fmmm phase, coupled with reported electronic and magnetic phase transition from ferromagnetic metal to antiferromagnetic insulator state has been started at similar to 200 K and completed at similar to 100 K. On the application of 8 T magnetic field this magneto-structural phase transition shifted to lower temperature (similar to 162 K) with phase coexistence regime down to 4.2 K. Isothermal X-ray diffraction measurements at 150 K infer the evidence of magnetic field driven first order structural phase transition from Fmmm to I4/mcm. These results consistent with the resistivity and magnetoresistance results; present the microscopic evidence of strong spin-lattice coupling and reveal the magnetic field driven structural phase transition as the origin of observed colossal magnetoresistance in this material. (C) 2016 Published by Elsevier B.V

Infield X-ray diffraction studies of field and temperature driven structural phase transition in Nd0.49Sr0.51MnO3+delta

Comprehensive X-ray diffraction (XRD) studies have been performed at different temperature (T) (4.2-300 K) and magnetic field (H) (0-8 T) to understand the evolution of crystal structure of Nd0.49Sr0.51MnO3+delta (NSMO) under non ambient conditions. The T dependent XRD results show the abrupt change in the lattice parameters without any change in lattice symmetry at similar to 200 K, which is associated with the first order structural phase transition from ferromagnetic to antiferromagnetic phase. This phase transition is strongly H dependent and shifted to lower temperature (similar to 150 K) on the application of 8 T field with phase coexistence (high temperature phase similar to 18%), even down to 4.2 K. Isothermal XRD results at 150 K under different H clearly illustrate the H induced first order structural phase transition. The critical H at which this phase transformation starts is similar to 1 T, with rapid growth above 4 T with hysteretic nature during increasing and decreasing H. These results are supported with the resistivity and magnetoresistance results and affirm the strong spin-lattice coupling in NSMO. Our detail studies reveal the structural correlations to the observed colossal magnetoresistance and magnetocaloric effect in this material. (C) 2017 Elsevier B.V. All rights reserved

Na substitution for La- and Mn-sites in LaMnO3LaMnO_3 from alkali halide fluxes: low temperature synthesis, structure and properties

$La_{1-x}Na_xMn_{1-y}Na_yO_3$ (0.12 < x < 0.16;0.04 < y < 0.07) have been synthesized from NaBr and NaI fluxes at relatively low temperature of 850 and $750^o\hspace{2mm}C$, respectively. Final composition of these oxides was obtained from chemical analysis of the elements present. The flux grown oxides crystallize in the rhombohedral structure (space group R-3c, No. 167) and are ferromagnetic metals (FMM). Chemical analysis and Rietveld refinement of X-ray data indicate Na ion is substituted for both La- and Mn-sites in the compound prepared from NaBr and NaI fluxes with 33 and 49% of $Mn^{4+}$ concentration, respectively

Strain-induced first-order orbital flip transition and coexistence of charge-orbital ordered phases in Pr(0.5)Ca(0.5)MnO(3)

Low-temperature transmission electron microscopy and x-ray diffraction (XRD) studies have been carried out on pellet and powder samples of Pr0.5 Ca0.5 MnO3. These studies have revealed appearance of a different type of charge-orbital ordered (COO) phase, resulting due to flipping of eg orbitals from d3 x2 - r2 / d3 y2 - r2 to d3 x2 - r2 / d3 z2 - r2 configuration. This orbital flip results in a changeover of the COO superlattice-ordering vector from (1/2,0,0) to (1/4,1/2,1/4) in the Pnma phase. This COO phase coexists with the conventional COO phase. Low-temperature XRD studies show that the COO phase appears only in pellet sample and not in the corresponding powder sample. The powder sample shows only conventional COO phase. Volume fractions of conventional and the other type COO phases in pellet sample of Pr0.5 Ca0.5 MnO3 is estimated to be ∼55% and 45%, respectively. The occurrence of orbital flip has been attributed to local strain building up in the pellet sample. The strain builds up during cooling because manganite has anisotropic thermal expansion coefficients. © 2008 The American Physical Society