Tumor‐associated macrophages (TAMs) are crucial components of the tumor microenvironment. They play vital roles in hepatocellular carcinoma (HCC) progression. However, the interactions between TAMs ...and HCC cells have not been fully characterized. In this study, TAMs were induced using human monocytic cell line THP‐1 cells in vitro to investigate their functions in HCC progression. S100 calcium‐binding protein A9 (S100A9), an inflammatory microenvironment‐related secreted protein, was identified to be significantly upregulated in TAMs. S100A9 expression in tumor tissues was associated with poor survival of HCC patients. It could enhance the stem cell‐like properties of HepG2 and MHCC‐97H cells by activating nuclear factor‐kappa B signaling pathway through advanced glycosylation end product‐specific receptor in a Ca2+‐dependent manner. Furthermore, we found that, after treatment with S100A9, HepG2 and MHCC‐97H cells recruited more macrophages via chemokine (CC motif) ligand 2, which suggests a positive feedback between TAMs and HCC cells. Taken together, our findings reveal that TAMs could upregulate secreted protein S100A9 and enhance the stem cell‐like properties of HCC cells and provide a potential therapeutic target for combating HCC.
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Prognosis of hepatocellular carcinoma (HCC) is influenced by tumor‐associated macrophages (TAMs) in the tumor microenvironment. Little is known, however, about how TAMs fuel HCC progression. This comparative analysis of RNA‐sequencing and whole‐genome expression profiling between TAMs and nonactivated M0 macrophages identified three common upregulated genes with potential impact on HCC prognosis. Among them, S100 calcium binding protein A9 (S100A9) was found to enhance stem cell‐like properties in HCC cells, via Ca2+‐dependent signaling along the AGER/NF‐κB axis. Moreover, S100A9 increased TAM infiltration by facilitating CCL2 secretion. The findings warrant further investigation of S100A9 secretion and enhanced HCC cell stemness by TAMs.
PD-L1 has been widely demonstrated to contribute to failed antitumor immunity. Blockade of PD-L1 with monoclonal antibody could modulate the tumor immune environment to augment immunotherapy. PD-L1 ...expression is also detected in several types of cancer and is associated with poor prognosis. However, the prognostic role of PD-L1 in oral squamous cell carcinoma (OSCC) is still controversial. Our aim was to determine the role of PD-L1 in the prognosis of OSCC patients to identify its potential therapeutic relevance. PD-L1 immunoreactivity was analyzed by immunohistochemistry in 305 cancer specimens from primary OSCC patients. The medium follow-up time after surgery was 3.8 years (range from 0.1 to 11.1 years). The prognostic value of PD-L1 on overall survival was determined by Kaplan-Meier analysis and Cox proportional hazard models. Higher PD-L1 expression is more likely in tumor tissues of female than male OSCC patients (P = 0.0062). Patients with distant metastasis also had high PD-L1 expression (P = 0.0103). Multivariate analysis identified high PD-L1 expression as an independent risk factor in males and smokers (males: hazard ratio = 1.556, P = 0.0077; smokers: hazard ratio = 2.058, P = 0.0004). We suggest that PD-L1 expression, determined by IHC staining, could be an independent prognostic marker for OSCC patients who are male or who have a smoking habit.
In this paper, we analytically study the phase structure and construct the Ruppeiner geometry in the extended phase space for the five-dimensional neutral Gauss-Bonnet AdS black hole. Through ...calculating the scalar curvature of the Ruppeiner geometry and combining the phase transition, we show that the attractive interaction is dominant in the microstructure of the black hole system. More significantly, there is an intriguing property that the normalized scalar curvature has the same expression for the saturated small and large black hole curves. This implies that although the microstructure is different before and after the small-large black hole phase transition, the interaction between the microscopic constituents keeps unchanged. These results are quite valuable on further understanding the microstructure of the AdS black hole in modified gravity.
Graphene has emerged as the most popular topic in the active research field since graphene's discovery in 2004 by Andrei Geim and Kostya Novoselov. Since then, graphene research has exponentially ...accelerated because of its extraordinary properties, which have attracted the interest of researchers all over the world. For example, among the key properties are its thermal conductivity, electrical conductivity, optical transparency, and mechanical properties. These remarkable properties of graphene show its promise for applications in different industries including optical electronics, photovoltaic systems and others. However, the large-scale production and transfer method onto target substrates of monolayer graphene for commercial and industrial applications are still under study in the improvement stage. Therefore, this review presents the state-of-the-art research activities and latest advancement in the synthesis of graphene using various carbon precursors including solid, liquid and gas carbon feedstocks. The characterization methods have also been critically discussed in this review. In addition, the advancement in the transfer methods onto target substrates for achieving clean and high-quality transferred graphene have been thoroughly reviewed. Furthermore, the current growth mechanisms of single and multilayer graphene have also been discussed.
Graphene has emerged as the most popular topic in the active research field since graphene's discovery in 2004 by Andrei Geim and Kostya Novoselov.
Recently, the fields of organic light‐emitting diodes (OLEDs) and light‐emitting electrochemical cells (LECs) have improved tremendously with regard to tunable emission, efficiency, brightness, and ...thermal stability. Imidazole derivatives are excellent deep blue‐green light‐emitting layers in the OLED or LEC devices. This Review summarizes the major breakthroughs of various electroluminescence (EL) layers with imidazole‐containing organic or organometallic derivatives, the molecular design principles, and their light‐emitting performances as effective EL materials. The highly tunable chemical structures and flexible molecular design strategies of imidazole‐based compounds are advantages that provide great opportunities for researchers. They can provide a good basis for the design and development of new EL materials with narrower emission and higher efficiency. Moreover, imidazole compounds have demonstrated breakthrough performances in thermally activated delayed fluorescence (TADF) properties where triplet excitons are utilized to inhibit anti‐intersystem quenching, showing great promise in breaking the theoretical external quantum efficiencies (EQE) limits in traditional fluorescent devices.
Imidazole emitters: In recent years, electroluminescent devices have flourished, and maximizing the efficiency of organic light‐emitting diodes (OLEDs) and light‐emitting electrochemical cells (LECs) has become the driving force and goal of a great deal of research. Imidazole derivatives have developed many excellent electroluminescent devices due to their structural diversity. This Review article discusses imidazole derivatives for fluorescent emitters and ligands as phosphorescent emitters and demonstrates their properties.
Removal of organic micropollutants from water through advanced oxidation processes (AOPs) is hampered by the excessive input of energy and/or chemicals as well as the large amounts of residuals ...resulting from incomplete mineralization. Herein, we report a new water purification paradigm, the direct oxidative transfer process (DOTP), which enables complete, highly efficient decontamination at very low dosage of oxidants. DOTP differs fundamentally from AOPs and adsorption in its pollutant removal behavior and mechanisms. In DOTP, the nanocatalyst can interact with persulfate to activate the pollutants by lowering their reductive potential energy, which triggers a non-decomposing oxidative transfer of pollutants from the bulk solution to the nanocatalyst surface. By leveraging the activation, stabilization, and accumulation functions of the heterogeneous catalyst, the DOTP can occur spontaneously on the nanocatalyst surface to enable complete removal of pollutants. The process is found to occur for diverse pollutants, oxidants, and nanocatalysts, including various low-cost catalysts. Significantly, DOTP requires no external energy input, has low oxidant consumption, produces no residual byproducts, and performs robustly in real environmental matrices. These favorable features render DOTP an extremely promising nanotechnology platform for water purification.
Biomass is increasingly perceived as a renewable resource rather than as an organic solid waste today, as it can be converted to various chemicals, biofuels, and solid biochar using modern processes. ...In the past few years, pyrolysis has attracted growing interest as a promising versatile platform to convert biomass into valuable resources. However, an efficient and selective conversion process is still difficult to be realized due to the complex nature of biomass, which usually makes the products complicated. Furthermore, various contaminants and inorganic elements (e.g., heavy metals, nitrogen, phosphorus, sulfur, and chlorine) embodied in biomass may be transferred into pyrolysis products or released into the environment, arousing environmental pollution concerns. Understanding their behaviors in biomass pyrolysis is essential to optimizing the pyrolysis process for efficient resource recovery and less environmental pollution. However, there is no comprehensive review so far about the fates of chemical elements in biomass during its pyrolysis. Here, we provide a critical review about the fates of main chemical elements (C, H, O, N, P, Cl, S, and metals) in biomass during its pyrolysis. We overview the research advances about the emission, transformation, and distribution of elements in biomass pyrolysis, discuss the present challenges for resource-oriented conversion and pollution abatement, highlight the importance and significance of understanding the fate of elements during pyrolysis, and outlook the future development directions for process control. The review provides useful information for developing sustainable biomass pyrolysis processes with an improved efficiency and selectivity as well as minimized environmental impacts, and encourages more research efforts from the scientific communities of chemistry, the environment, and energy.
Chemodivergent tandem radical cyclization offers exciting possibilities for the synthesis of structurally diverse cyclic compounds. Herein, we revealed a chemodivergent tandem cyclization of ...alkene‐substituted quinazolinones under metal‐ and base‐free conditions, this transformation is initiated by alkyl radicals produced from oxidant‐induced α‐C(sp3)−H functionalization of alkyl nitriles or esters. The reaction resulted in the selective synthesis of a series of mono‐ and di‐alkylated ring‐fused quinazolinones by modulating the loading of oxidant, reaction temperature, and reaction time. Mechanistic investigations show that the mono‐alkylated ring‐fused quinazolinones is constructed by the key process of 1,2‐hydrogen shift, whereas the di‐alkylated ring‐fused quinazolinones is mainly achieved through crucial steps of resonance and proton transfer. This protocol is the first example of remote second alkylation on the aromatic ring via α‐C(sp3)−H functionalization and difunctionalization achieved by association of two unsaturated bonds in radical cyclization.
A novel method for preparing mono‐ and di‐alkylated ring‐fused quinazolinones from alkene‐substituted quinazolinones via chemodivergent tandem radical cyclization under metal‐ and base‐free conditions has been established.
Nitrogenase is the only enzyme in nature that can fix N2 from the air. The active cofactor of the leading form of this enzyme contains seven irons and one molybdenum connected by sulfide bridges. In ...several recent experimental studies, it has been suggested that the cofactor is very flexible, and might lose one of its sulfides during catalysis. In this study, the possible loss of a sulfide has been investigated by model calculations. In previous studies, we have shown that there should be four activation steps before catalysis starts, and this study is based on that finding. It was found here that, after the four reductions in the activation steps, a sulfide will become very loosely bound and can be released in a quite exergonic step with a low barrier. The binding of N2 has no part in that release. In our previous studies, we suggested that the central carbide should be protonated three times after the four activation steps. With the new finding, there will instead be a loss of a sulfide, as the barrier for the loss is much lower than the ones for protonating the carbide. Still, it is suggested here that the carbide will be protonated anyway, but only with one proton, in the E3 to E4 step. A very complicated transition state for H2 formation involving a large structural change was obtained. The combined step, with a loss of H2 and binding of N2, is calculated to be endergonic by +2.3 kcal mol−1; this is in excellent agreement with experiments in which an easily reversible step has been found.
Lost property: The possible loss of a sulfide mechanism for the Mo‐nitrogenase has been investigated by hybrid DFT using a cluster model. The calculations show that, after four reductions, a sulfide can be released as a H2S group. After another four reductions, the central carbon is protonated with one proton in E4, from where the loss of H2 and binding of N2 is reversible.
Nitrogen‐containing compounds widely exist in pharmaceuticals and multifunctional materials. Thus, the development of C−N bond formation reactions is of great importance in synthetic chemistry. Since ...2014, obvious progress has been made in the construction of C−N bonds via metal‐free radical C(sp3)−H functionalization, which is one of the major protocols due to its high reaction activity and mild conditions. To the best of our knowledge, there are still no exclusive reviews about the formation of C−N bonds through metal‐free radical C(sp3)−H functionalization. This review aims to highlight the recent advances in this area since 2014, according to the type of the nitrogen source (amines, amides, sulfonamides, azoles, azides and other nitrogen sources). The paper is focused on discussions about the reaction mechanisms and selected examples of substrates have also been listed.
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