MOLECULAR MECHANISMS OF THROMBOXANE A2 RECEPTOR-MEDIATED INVASION IN LUNG CANCER CELLS

Thromboxane A2 receptor (TP) has been shown to play important roles in multiple aspects of cancer development including regulation of tumor growth, survival and metastasis. Molecular mechanisms of TP mediated cancer cell invasion remain to be identified. TP agonist, I-BOP, significantly elevated several matrix metalloproteinases (MMPs) including MMP-1, MMP-3, MMP-9 and MMP-10 in A549 human lung adenocarcinoma cells overexpressing TPα (A549-TPα) or TPβ (A549-TPβ). Signaling pathways of I-BOP-induced MMP-1 expression were examined in further detail as a model system for MMPs induction. Signaling molecules involved in I-BOP-induced MMP-1 expression were identified by using specific inhibitors including small interfering (si)-RNAs of signaling molecules and promoter reporter assay. The results indicate that I-BOP-induced MMP-1 expression is mediated by protein kinase C (PKC), extracellular signal-regulated kinase (ERK)-activator protein-1(AP-1) and ERK-CCAAT/enhancer-binding protein β (C/EBPβ) pathways. I-BOP-induced cellular invasiveness of A549-TPα cells was blocked by, GM6001, a general inhibitor of MMPs. Knockdown of MMP-1 and MMP-9 by their respective siRNA partially reduced I-BOP-stimulated A549-TPα cells invasion suggesting that other MMPs induced by I-BOP were also involved. Furthermore, secreted MMP-1 in conditioned media from I-BOP-treated A549-TPα cells (CM-I-BOP) autocrinely induced monocyte chemoattractant protein-1 (MCP-1) expression. The induction of MCP-1 by MMP-1 in A549 cells was via activation of protease-activated receptor 2 (PAR2) instead of commonly assumed PAR1. This conclusion was reached from the following findings: (1) expression of MCP-1 induced by trypsin, a PAR2 agonist, was inhibited by a PAR2 antagonist. (2) expression of MCP-1 induced by MMP-1 and by CM-I-BOP was blocked by a PAR2 antagonist but not by other PAR antagonists; (3) expression of MCP-1 induced by MMP-1 and by CM-I-BOP was attenuated significantly by pretreatment of cells with PAR2-siRNA. Finally, MCP-1 also can be induced by direct activation of TP in a SP1 involved mechanism. CM-I-BOP enhanced MCP-1-dependent migration of RAW 264.7 macrophages. Co-culture of A549 cells with RAW 264.7 macrophages induced expression of MMPs, VEGF and MCP-1 genes, and increased the invasive potential in A549 cells. My studies provide molecular mechanisms by which TP-mediated cancer cell invasion and suggest that TP is a potential anti-cancer drug target

Study on Growth and Change of Solid Particles with Water Flow in Oilfield Water-Injection Pipeline

The solid particles in oilfield water-injection pipelines with water flow will continuously grow and change, and the oversized solid particles may block the pores of the formation and reduce the oilfield recovery efficiency. Therefore, the study on the growth and change to solid particles during transportation has become a question of interest in oilfields. However, there is little research on this question currently. Therefore, on the basis of the liquid-solid two-phase flow model and the particle population balance model, a growth and change model of solid particles in long-distance water-injection pipelines flowing along water was established in this paper in consideration of the injected water temperature drop along the path, as well as the growth, coalescence, breakage and deposition of particles. Comparison of the field test results indicated that the average error of the particle size distribution fitting degree calculated by the model is 6.9%, and the average error of median diameter is 4.1%. This model was used for analyzing the impact of the flow rate, temperature and median diameter of the united station outlet in a block oilfield of Shengli Oilfield on the solid particle size of the wellheads, and the critical flow rate, temperature and median diameter of the united station outlet were predicted when the median diameter at the wellheads meets the injection requirement (< 2 μm). The establishment of this model cannot only be used for the study on the growth and change to solid particles in water-injection pipelines flowing along water, but also provides a technical reference for the study on the growth and change to low-concentration solid particles accompanying flow in long-distance liquid/gas phase pipelines

Does green finance promote the social responsibility fulfilment of highly polluting enterprises? – empirical evidence from China

This study explores whether and how the development of green finance can facilitate the social responsibility of highly polluting enterprises. We conducted a quasi-natural experiment in 2017 in five Chinese provinces (districts), based on the establishment of green finance reform and innovation pilot zones. The research samples were China’s A-share heavy pollution-industry-listed companies from 2013 to 2020, and the difference in differences model was used to examine the relationship between green finance and social responsibility fulfilment of highly polluting firms. The mediating and moderating effects of financial constraints and media monitoring were also discussed. The findings indicate that the advancement of green finance significantly improves the level of social responsibility fulfilment of highly polluting firms, particularly in the area of environmental responsibility. Furthermore, strengthened financing constraints partially mediate the aforementioned relationship, and media monitoring positively moderates the facilitation effect of green finance development on highly polluting firms’ social responsibility fulfilment. Our study demonstrates that a higher degree of financing constraints is an important channel for establishing a green finance reform and innovation pilot zone to force enterprises to fulfilment their social responsibility, and provides theoretical support for governments and enterprises to better understand the policy effects

Turning non-magnetic two-dimensional molybdenum disulfide into room temperature magnets by the synergistic effect of strain engineering and charge injection

The development of two-dimensional (2D) room temperature magnets is of great significance to the practical application of spintronic devices. However, the number of synthesized intrinsic 2D magnets is limited and the performances of them are not satisfactory, e.g. typically with low Curie temperature and poor environmental stability. Magnetic modulation based on developed 2D materials, especially non-magnetic 2D materials, can bring us new breakthroughs. Herein, we report room temperature ferromagnetism in halogenated MoS2 monolayer under the synergistic effect of strain engineering and charge injection, and the combined implementation of these two processes is based on the halogenation of MoS2. The adsorbed halogen atoms X (X = F, Cl, and Br) on the surface leads to lattice superstretching and hole injection, resulting in MoS2 monolayer exhibiting half-metallic properties, with one spin channel being gapless in the band structure. The Curie temperature of halogenated MoS2 monolayer is 513~615 K, which is much higher than the room temperature. In addition, large magnetic anisotropy energy and good environmental stability make halogenated MoS2 display great advantages in practical spintronic nanodevices

Demonstration of the first monolithically integrated self-rolled-up tube based vertical photonic coupler

We demonstrated the first monolithically integrated self-rolled-up SiN_x tube based vertical photonic coupler on top of a planar ridge waveguide. The coupling efficiency between the elements is >10 times higher than similar non-integrated device

Serum amyloid P down-regulates CCL-1 expression, and inhibits Ras/MAPK signaling and development of breast cancer

Purpose: To investigate the role of serum amyloid component P (SAP) on Ras/MAPK pathway in the development of breast cancer (BC) via regulation of chemokine (CC motif) ligand 1 (CCL-1).Methods: Breast cancer (BC) and metastasis models were established using SAP-Tg transgenic mice and WT C57BL/6 mice. The effect of SAP on growth and metastasis was observed. Differentially expressed proteins in SAP-Tg and C57BL/6 serum were analyzed, and further determined by enzymelinked immunosorbent assay (ELISA) and quantitative polymerase chain reaction (qPCR). The effect of SAP on CCL1/Ras/MAPK signaling pathway was studied by immunoblotting.Results: Compared with WT control, SAP-Tg BC model showed a significant reduction in tumor volume and prolonged survival (p &lt; 0.05). In the lung metastasis model, SAP-Tg mice showed a decreased number of nodules on the organ surface (p &lt; 0.05). Protein microarray screening results showed that SAP inhibited CCL-1 expression (p &lt; 0.05). CCL-1 mRNA level in SAP-Tg mice was significantly lower than WT control (p &lt; 0.05). After stimulating RAW cells (mouse macrophage line) with SAP recombinant protein, ELISA results showed that CCL-1 secretion significantly decreased (p &lt; 0.05). In both models, P38 and ERK1/2 activation in SAP-Tg mice were significantly lower than that in C57BL/6 mice.Conclusion: SAP inhibits the growth and metastasis of BC, possibly by reducing the secretion of CCL- 1 and inhibiting Ras/MAPK signaling pathway, thus suggesting a possible treatment strategy for breast cancer.Keywords: Serum amyloid component P (SAP), chemokine (CC motif) ligand 1 (CCL-1), Breast cancer, NF-κB, Ras/MAPK signaling pathwa

Retracted “Serum amyloid P down-regulates CCL-1 expression, and inhibits Ras/MAPK signaling and development of breast cancer”

This article previously published in Volume 17 Issue 16 of this journal in September 2017 has been retracted in line with the guidelines from the Committee on Publication Ethics (COPE,http://publicationethics.org/ resources/guidelines). Retraction: Ding S, Li H, Li X, Wang W, Du X, Dong G, Zhang P. Serum amyloid P down-regulates CCL-1 expression, and inhibits Ras/MAPK signaling and development of breast cancer. Trop J Pharm Res 2017; 16(9):2089-2095 doi: http://dx.doi.org/10.4314/tjpr.v16i9.7 To the editor: The figures in the paper were plagiarized partly from an earlier published article, Qi et al, P-selectinmediated tablet adhesion promoters tumor growth. Oncotarget 2015;30:6(9):6584–6596, and data from a master's thesis submitted by Bin Li under the supervision of Professor Lijing Wang and Professor Cuiling Qi. Sincerely, Cuiling Qi and Lijing Wang

Spectroscopic Studies of the Modification of Crystalline Si(111) Surfaces with Covalently-Attached Alkyl Chains Using a Chlorination/Alkylation Method

A two-step procedure, involving radical-initiated chlorination of the Si surface with PCl_5 followed by reaction of the chlorinated surface with alkyl-Grignard or alkyl-lithium reagents, has been developed to functionalize crystalline (111)-oriented H-terminated Si surfaces. The surface chemistry that accompanies these reaction steps has been investigated using X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), temperature programmed desorption spectroscopy (TPDS), high-resolution electron energy loss spectroscopy (HREELS), infrared (IR) spectroscopy in both glancing transmission (TIR) and attenuated total multiple internal reflection (ATR) modes, ellipsometry, and contact angle goniometry. The XPS data show the appearance of the Cl signal after exposure to PCl_5 and show its removal, and concomitant appearance of a C 1s signal, after the alkylation step. Auger electron spectra, in combination with TPD spectroscopy, demonstrate the presence of Cl after the chlorination process and its subsequent loss after thermal desorption of Si−Cl fragments due to heating the Si surface to 1200 K. High-resolution XP spectra of the Si 2p region show a peak corresponding to Si−Cl bond formation after the chlorination step, and show the subsequent disappearance of this peak after the alkylation step. IR spectra show the loss of the perpendicularly polarized silicon monohydride (Si−H) vibration at 2083 cm^(-1) after the chlorination step, whereas HREELS data show the appearance of vibrations due to Si−Cl stretches upon chlorination of the Si surface. The HREELS data furthermore show the disappearance of the Si−Cl stretch and the appearance of a Si−C vibration at 650 cm^(-1) after alkylation of the Si surface. Ellipsometric measurements indicate that the thickness of the alkyl overlayer varies monotonically with the length of the alkyl group used in the reactant. Contact angle and IR measurements indicate that the packing of alkyl groups in the monolayers produced by this method is less dense than that found in alkylthiol monolayers on Au. As determined by XPS, the alkylated surfaces show enhanced resistance to oxidation by various wet chemical treatments, compared to the H-terminated Si surface. The two-step reaction sequence thus provides a simple approach to functionalization of (111)-oriented, H-terminated silicon surfaces using wet chemical methods