Hydrothermal Stability of Core–Shell Pd@Ce_0.5Zr_0.5O₂/Al₂O₃ Catalyst for Automobile Three-Way Reaction

In this paper, the hydrothermal stability and catalytic activity of Pd@Ce_0.5Zr_0.5O₂/Al₂O₃ catalyst with a core–shell structure were investigated for automobile three-way reactions and compared with those of Pd/Al₂O₃, Pd@CeO₂/Al₂O₃, and Pd@ZrO₂/Al₂O₃ catalysts. TEM, HRTEM, and EDS mapping analyses showed that the core–shell structure of Pd@Ce_0.5Zr_0.5O₂ nanoparticles was intact after the hydrothermal treatment at 1050 °C for 5 h. Meanwhile, CO–DRIFT results suggested that the interface of Pd core and Ce_0.5Zr_0.5O₂ shell acted as the active sites in the reaction of three-way catalysts. Additionally, XPS, FT-IR, and CO–DRIFT analyses demonstrated that a large amount of OH groups were present on the surface of Pd@Ce_0.5Zr_0.5O₂/Al₂O₃ catalyst, which could accelerate the decomposition of carbonate species and reduce the activation energy of the catalytic reaction. This was an important reason for the Pd@Ce_0.5Zr_0.5O₂/Al₂O₃ catalyst to keep the high catalytic activity after aging at high temperature

The effect of DP on the morphological characteristics and the viability of SW620 cells.

<p>A, Morphological changes of SW620 cells observed under phase-contrast microscopy (100 × magnification) after treating cells with (a) control, (b) 5 μM, (c) 10 μM, (d) 20 μM, (e) 40 μM or (f) 80 μM of DP for 24 h. B, SW620 cells were treated with various concentrations (0, 5, 10, 20 40 and 80 μM) of DP for 24 or 48 h, as described in the methods. Cell viability was measured using the MTT assay. The results are expressed as the mean ± S.D. (n = 3); * p < 0.05.</p

Inhibition of TMEM16A Expression Suppresses Growth and Invasion in Human Colorectal Cancer Cells

<div><p>Metastasis leads to poor prognosis in colorectal cancer patients, and there is a growing need for new therapeutic targets. TMEM16A (ANO1, DOG1 or TAOS2) has recently been identified as a calcium-activated chloride channel (CaCC) and is reported to be overexpressed in several malignancies; however, its expression and function in colorectal cancer (CRC) remains unclear. In this study, we found expression of TMEM16A mRNA and protein in high-metastatic-potential SW620, HCT116 and LS174T cells, but not in primary HCT8 and SW480 cells, using RT-PCR, western blotting and immunofluorescence labeling. Patch-clamp recordings detected CaCC currents regulated by intracellular Ca²⁺ and voltage in SW620 cells. Knockdown of TMEM16A by short hairpin RNAs (shRNA) resulted in the suppression of growth, migration and invasion of SW620 cells as detected by MTT, wound-healing and transwell assays. Mechanistically, TMEM16A depletion was accompanied by the dysregulation of phospho-MEK, phospho-ERK1/2 and cyclin D1 expression. Flow cytometry analysis showed that SW620 cells were inhibited from the G1 to S phase of the cell cycle in the TMEM16A shRNA group compared with the control group. In conclusion, our results indicate that TMEM16A CaCC is involved in growth, migration and invasion of metastatic CRC cells and provide evidence for TMEM16A as a potential drug target for treating metastatic colorectal carcinoma.</p></div

Effects of DP on TMEM16A expression.

<p>TMEM16A protein expression were determined by western blotting after SW620 cells were treated with 5 μM of DP for 24, 48 or 72 h (above). Control SW620 cells were treated with DMSO for 24 h. β-actin was used as a loading control. Representative western blots are shown. The bar graph summarizes the relative expression level of TMEM16A protein (below). Expression of TMEM16A protein was normalized with the expression levels of β-actin. All data are shown as the mean ± SD. n = 3; * p < 0.05, ** p < 0.01.</p

Effects of DP on SW620 cell motility.

<p>Migration of SW620 cells was assessed by a wound-healing assay in the presence of 5 μM DP, compared to the control group. Representative images of wound closure were taken at 0, 24, 48 and 72 h after injury under 40 × magnification (above). Bar graphs of wound area are shown (below). Values are the means ± SD; n = 3; ** p < 0.01. Ctrl, control.</p

TMEM16A knockdown induced a decrease in proliferation of SW620 cells.

<p>A, The growth of SW620 cells was inhibited by TMEM16A shRNA #1 and #2 compared to the control group (Mean ± SD; n = 3; * P<0.05). B, Representative immunoblots confirming knockdown of TMEM16A. Ctrl, control.</p

Scratch wound assay of TMEM16A shRNA on SW620 cells.

<p>A, Migration of SW620 cells was assessed by a wound-healing assay in the presence of TMEM16A shRNA #1 and shRNA #2, compared with control shRNA. Representative images of wound closure were taken at 0 h, 24 h, 48 h and 72 h after wounding under 100× magnification. B, Bar graphs of panel A are shown. Values are the means ± SD; n = 3; ** P<0.01. Ctrl, control.</p

Effects of DP on SW620 cell migration and invasion <i>in vitro</i>.

<p>Migration (without Matrigel) and invasion (with Matrigel) of SW620 cells are significantly suppressed by 5 μM DP compared with the control group through transwell penetration assays. Non-migrated cells were scraped with a cotton swab. Cells that penetrated the transwell filters were stained with Coomassie blue. Representative images are shown (above). Bar graphs showed cells number per field of SW620 cell migration (lower left) or invasion (lower right). All data are shown as the mean ± SD. n = 3; ** p < 0.01. Ctrl, control.</p

Identification of a small molecule inhibitor (DP) of human TMEM16A.

<p>A, FRT cells stably transfected with human TMEM16A and GFP showing green membrane fluorescence (above) and TMEM16A protein by western blotting (below). B, Examples of whole-cell currents recorded from FRT-TMEM16A cells at a holding potential of 0 mV, followed by pulsing voltages between ±100 mV in steps of 20 mV in the absence (above) or presence of 50 μM DP (below). TMEM16A CaCC currents were elicited by 600 nM of free calcium in pipette solution. C, Current/voltage (I/V) plot of the mean currents at the middle of each voltage pulse. D, Chemical structure of DP. E, CFTR Cl^- current trace recorded from CFTR-expressing FRT cells. CFTR Cl^- current was elicited by 1 mM ATP, followed by the addition of DP and CFTR_inh-172. The dashed line represents zero current. F, The bars represent the percentage inhibition of DP (n = 6) and CFTR_inh-172 (n = 4) on CFTR Cl^- current.</p

Effect of T16Ainh-A01 on growth of SW480 and SW620 cells.

<p>Cells were treated with different concentrations of T16Ainh-A01 for 24 h and cell viability was measured by MTT assay. Data are expressed as Mean ± SD (n = 3).</p