Plakophilin3 Loss Leads to an Increase in PRL3 Levels Promoting K8 Dephosphorylation, Which Is Required for Transformation and Metastasis

The desmosome anchors keratin filaments in epithelial cells leading to the formation of a tissue wide IF network. Loss of the desmosomal plaque protein plakophilin3 (PKP3) in HCT116 cells, leads to an increase in neoplastic progression and metastasis, which was accompanied by an increase in K8 levels. The increase in levels was due to an increase in the protein levels of the Phosphatase of Regenerating Liver 3 (PRL3), which results in a decrease in phosphorylation on K8. The increase in PRL3 and K8 protein levels could be reversed by introduction of an shRNA resistant PKP3 cDNA. Inhibition of K8 expression in the PKP3 knockdown clone S10, led to a decrease in cell migration and lamellipodia formation. Further, the K8 PKP3 double knockdown clones showed a decrease in colony formation in soft agar and decreased tumorigenesis and metastasis in nude mice. These results suggest that a stabilisation of K8 filaments leading to an increase in migration and transformation may be one mechanism by which PKP3 loss leads to tumor progression and metastasis

Fascin overexpression promotes neoplastic progression in oral squamous cell carcinoma

<p>Abstract</p> <p>Background</p> <p>Fascin is a globular actin cross-linking protein, which plays a major role in forming parallel actin bundles in cell protrusions and is found to be associated with tumor cell invasion and metastasis in various type of cancers including oral squamous cell carcinoma (OSCC). Previously, we have demonstrated that fascin regulates actin polymerization and thereby promotes cell motility in K8-depleted OSCC cells. In the present study we have investigated the role of fascin in tumor progression of OSCC.</p> <p>Methods</p> <p>To understand the role of fascin in OSCC development and/or progression, fascin was overexpressed along with vector control in OSCC derived cells AW13516. The phenotype was studied using wound healing, Boyden chamber, cell adhesion, Hanging drop, soft agar and tumorigenicity assays. Further, fascin expression was examined in human OSCC samples (N = 131) using immunohistochemistry and level of its expression was correlated with clinico-pathological parameters of the patients.</p> <p>Results</p> <p>Fascin overexpression in OSCC derived cells led to significant increase in cell migration, cell invasion and MMP-2 activity. In addition these cells demonstrated increased levels of phosphorylated AKT, ERK1/2 and JNK1/2. Our in vitro results were consistent with correlative studies of fascin expression with the clinico-pathological parameters of the OSCC patients. Fascin expression in OSCC showed statistically significant correlation with increased tumor stage (<it>P </it>= 0.041), increased lymph node metastasis (<it>P </it>= 0.001), less differentiation (<it>P </it>= 0.005), increased recurrence (<it>P </it>= 0.038) and shorter survival (<it>P </it>= 0.004) of the patients.</p> <p>Conclusion</p> <p>In conclusion, our results indicate that fascin promotes tumor progression and activates AKT and MAPK pathways in OSCC-derived cells. Further, our correlative studies of fascin expression in OSCC with clinico-pathological parameters of the patients indicate that fascin may prove to be useful in prognostication and treatment of OSCC.</p

Versatile hemidesmosomal linker proteins: Structure and function

Hemidesmosomes are anchoring junctions which connect basal epidermal cells to the extracellular matrix. In complex epithelia like skin, hemidesmosomes are composed of transmembrane proteins like α6β4 integrin, BP180, CD151 and cytoplasmic proteins like BPAG1e and plectin. BPAG1e and plectin are plakin family cytolinker proteins which anchor intermediate filament proteins i.e. keratins to the hemidesmosomal transmembrane proteins. Mutations in BPAG1e and plectin lead to severe skin blistering disorders. Recent reports indicate that these hemidesmosomal linker proteins play a role in various cellular processes like cell motility and cytoskeleton dynamics apart from their known anchoring function. In this review, we will discuss their role in structural and signaling functions

Polymer-Based Membranes for C₃₊ Hydrocarbon Removal from Natural Gas

Natural gas can contain significant amounts of impurifies, including CO2, H2S, N2, He, and C3+ hydrocarbons. These C3+ hydrocarbons are valuable chemical feedstocks and can be used as a liquid fuel for power generation. Membrane-based separation technologies have recently emerged as an economically favorable alternative due to reduced capital and operating cost. Polymeric membranes for the separation and removal of C3+ hydrocarbons from natural gas have been practiced in chemical and petrochemical industries. Therefore, these industries can benefit from membranes with improved C3+ hydrocarbon separation. This chapter overviews the different gas processing technologies for C3+ hydrocarbon separation and recovery from natural gas, highlighting the advantages, research and industrial needs, and challenges in developing highly efficient polymer-based membranes. More specifically, this chapter summarizes the removal of C3H8 and C4H10 from CH4 by prospective polymer architectures based on reverse-selective glassy polymers, rubbery polymers, and its hybrid mixed matrix membranes. In addition, the effect of testing conditions and gas compositions on the membrane permeation properties (permeability and selectivity) is reviewed

Functional implications of O-GlcNAcylation-dependent phosphorylation at a proximal site on keratin 18

Keratins 8/18 (K8/18) are phosphoglycoproteins and form the major intermediate filament network of simple epithelia. The three O-GlcNAcylation (Ser , Ser , and Ser ) and two phosphorylation (Ser and Ser ) serine sites on K18 are well characterized. Both of these modifications have been reported to increase K18 solubility and regulate its filament organization. In this report, we investigated the site-specific interplay between these two modifications in regulating the functional properties of K18, like solubility, stability, and filament organization. An immortalized hepatocyte cell line (HHL-17) stably expressing site-specific single, double, and triple O-GlcNAc and phosphomutants of K18 were used to identify the site(s) critical for regulating these functions. Keratin 18 mutants where O-GlcNAcylation at Ser was abolished (K18-S30A) exhibited reduced phosphorylation induced solubility, increased stability, defective filament architecture, and slower migration. Interestingly, K18-S30A mutants also showed loss of phosphorylation at Ser , a modification known to regulate the solubility of K18. Further to this, the K18 phosphomutant (K18-S33A) mimicked K18-S30A in its stability, filament organization, and cell migration. These results indicate that O-GlcNAcylation at Ser promotes phosphorylation at Ser to regulate the functional properties of K18 and also impact cellular processes like migration. O-GlcNAcylation and phosphorylation on the same or adjacent sites on most proteins antagonize each other in regulating protein functions. Here we report a novel, positive interplay between O-GlcNAcylation and phosphorylation at adjacent sites on K18 to regulate its fundamental properties

Differential Ratios of Omega Fatty Acids (AA/EPA+DHA) Modulate Growth, Lipid Peroxidation and Expression of Tumor Regulatory MARBPs in Breast Cancer Cell Lines MCF7 and MDA-MB-231

<div><p>Omega 3 (n3) and Omega 6 (n6) polyunsaturated fatty acids (PUFAs) have been reported to exhibit opposing roles in cancer progression. Our objective was to determine whether different ratios of n6/n3 (AA/EPA+DHA) FAs could modulate the cell viability, lipid peroxidation, total cellular fatty acid composition and expression of tumor regulatory Matrix Attachment Region binding proteins (MARBPs) in breast cancer cell lines and in non-cancerous, MCF10A cells. Low ratios of n6/n3 (1:2.5, 1:4, 1:5, 1:10) FA decreased the viability and growth of MDA-MB-231 and MCF7 significantly compared to the non-cancerous cells (MCF10A). Contrarily, higher n6/n3 FA (2.5:1, 4:1, 5:1, 10:1) decreased the survival of both the cancerous and non-cancerous cell types. Lower ratios of n6/n3 selectively induced LPO in the breast cancer cells whereas the higher ratios induced in both cancerous and non-cancerous cell types. Interestingly, compared to higher n6/n3 FA ratios, lower ratios increased the expression of tumor suppressor MARBP, SMAR1 and decreased the expression of tumor activator Cux/CDP in both breast cancer and non-cancerous, MCF10A cells. Low n6/n3 FAs significantly increased SMAR1 expression which resulted into activation of p21^WAF1/CIP1 in MDA-MB-231 and MCF7, the increase being ratio dependent in MDA-MB-231. These results suggest that increased intake of n3 fatty acids in our diet could help both in the prevention as well as management of breast cancer.</p></div

Effect of preparation on magnetic properties of Mn-Zn ferrite

289-294Mixed ferrites belonging to the type Mn0.9Zn0.1Fe2O4 have been prepared by the double sintering method and by the chemical co-precipitation for comparing their magnetic properties. Sintered and precipitated ferrites exhibit different characteristics, especially in their magnetic properties like magnetization (Ms), coercive field (Hc) and Curie temperature (Tc). The sintered particles were size reduced in order to compare with the nanosized co-precipitated particles. The effect of grinding has also been studied. Particles have been collected at regular intervals of grinding and their properties have been studied. The increase in the coercive field has been recorded by a hysteresis curve tracer confirming size reduction. X-ray diffraction studies confirmed the structure and consequent size reduction

Effect of preparation on magnetic properties of Mn-Zn ferrite

Mixed ferrites belonging to the type Mn0.9Zn0.1Fe2O4 have been prepared by the double sintering method and by the chemical co-precipitation for comparing their magnetic properties. Sintered and precipitated ferrites exhibit different characteristics, especially in their magnetic properties like magnetization (Ms), coercive field (Hc) and Curie temperature (Tc). The sintered particles were size reduced in order to compare with the nanosized co-precipitated particles. The effect of grinding has also been studied. Particles have been collected at regular intervals of grinding and their properties have been studied. The increase in the coercive field has been recorded by a hysteresis curve tracer confirming size reduction. X-ray diffraction studies confirmed the structure and consequent size reductionCochin University of Science and TechnologyIndian Journal of Engineering & Materials Sciences Vol. 11, August 2004, pp. 289-29

Relative percentage of total n6/n3 and EPA+DHA/AA ratio in breast cancer cells.

<p>The cells were treated with different ratios of n6 and n3 FA for 24h. The levels of total n6/n3 and EPA+DHA/AA has been shown in MDA-MB-231 (A) and MCF7 (B) cells treated with low and high n6/n3 ratios, respectively. Total n6 fatty acids include Linoleic acid (LA) (18:2n6), Gamma-linolenic acid (GLA) (18:3n6), Dihomo-gamma-linolenic acid (DGLA) (20:3n6), Arachidonic acid (AA) (20:4n6); Total n3 fatty acids include ALA (18:3n3), EPA (20:5n3), DHA (22:6n3), DPA(22:5n3). Each value represents mean±SEM of three independent experiments. %p<0.05 and *p<0.001 compared to UC; Ϫp<0.05, ¥p<0.01 and ¤p<0.001 compared to 1:1; ₭p<0.01, Φp<0.01 and Θp<0.001 compared to 1:2.5; #p<0.05, Λp<0.01 and Øp<0.001 compared to 1:4; $p<0.05, ϒp<0.01 and ϙp<0.001 compared to 1:5; βp<0.05, ×p<0.001 and ßp<0.001 compared to 1:10.</p

Effect of different concentrations of EPA, DHA and AA on viability of non-cancerous transformed cells.

<p>(A) MCF10A, (B) HEK293 and (C) HaCaT cells were exposed to different concentrations (0–320μM) of either EPA, DHA, AA and MTT assay was performed. Data has been presented as mean±SEM of three independent experiments, performed in 96 well plates. Statistical significance was assayed by one-way ANOVA, followed by a Dunnett's test. ***p<0.01.</p