Effects of temperature on microstructures of MSA-type electroplating solution: a coarse-grained molecular dynamics simulation.

In this study, we employ coarse-grained molecular dynamics simulations to explore the microstructure of MSA (methanesulfonic acid)-type electroplating solution, containing Sn(MSA)2 as the primary salt, MSA as the stabilizer, amphiphilic alkylphenol ethoxylate (APEO) as surfactants and cinnamaldehyde (CA) as the brightener agents, as well as water as the solvent. Our simulation indicates that temperature variations can significantly affect the structural properties of the electroplating solution and the adsorption behavior of its key components onto the substrate. Specifically, at low temperatures, the primary salt ions aggregate into ionic clusters, and the amphiphilic APEO surfactants and CA molecules form micelles composed of hydrophobic cores and hydrophilic shells, which reduces the uniformity of the solution and hinders the adsorption of ions, CA and surfactants onto the substrate. Appropriately increasing the temperature can weaken the aggregation of these components in bulk solution due to the accelerated molecular movements and arouse their adsorption. However, on further increasing the temperature, the elevated kinetic energy of the components thoroughly overwhelms the adsorption interactions, and therefore, the ions, surfactants, and CA desorb from the substrate and redissolve into the solution. We systematically analyze the complex interactions between these components at different temperatures and clarify the mechanism of the non-monotonic dependence of adsorption strength on the temperature at the molecular level. Our simulations demonstrate that there is low-temperature scope for reprocessing/recycling and intermediate-temperature scope for substrate-adsorptions of the key components. This study confers insights into a fundamental understanding of the microscopic mechanism for electroplating and can provide guidance for the development of precise electroplatings.

UBE2S promotes cell chemoresistance through PTEN-AKT signaling in hepatocellular carcinoma.

Ubiquitination displays a crucial role in various biological functions, such as protein degradation, signal transduction, and cellular homeostasis. Accumulating evidence has indicated that ubiquitination is essential in cancer progression. Ubiquitin-conjugating enzyme E2S (UBE2S) is a member of ubiquitin-conjugating enzyme family of the ubiquitin system and its role in hepatocellular cancer (HCC) is largely unknown. We investigated the role of UBE2S in HCC and found UBE2S upregulation is relevant with large tumor size, recurrence, and advanced TNM stage, serving as an independent risk factor of overall survival (OS) and disease-free survival (DFS) for HCC patients. We conducted in vitro experiments and found that in HCC cells, UBE2S overexpression increases the resistance to 5-FU and oxaliplatin, while UBE2S knockdown achieves an opposite effect. UBE2S is transcriptionally activated by the binding of FOXM1 to UBE2S promoter, which induces its upregulation and reduces PTEN protein level by promoting PTEN ubiquitination at Lys60 and Lys327 and facilitating AKT phosphorylation. The promotional effect of FOXM1-UBE2S axis on HCC cell chemoresistance is attenuated by allosteric AKT inhibitor, MK2206. In conclusion, our results reveal that UBE2S is a prognostic biomarker for HCC patients, and the FOXM1-UBE2S-PTEN-p-AKT signaling axis might be a promising target for the treatment of HCC.

Long non­coding RNA H19 is involved in sorafenib resistance in hepatocellular carcinoma by upregulating miR­675.

Sorafenib is the first­line treatment for advanced hepatocellular carcinoma (HCC). Since many HCC patients experience drug resistance, there is an urgent need to discover more effective therapeutic strategies to overcome drug resistance. Long non­coding RNAs (lncRNAs) play an important role in tumor drug resistance. However, research on the role of lncRNA H19 in sorafenib resistance in HCC is quite limited. In the present study, CCK­8 assay, RT­qPCR, EdU staining, immunofluorescence staining, and western blot analysis were used to detect the effect of lncRNA H19 on sorafenib resistance of HCC cells. H19 expression was found to be negatively related to sorafenib sensitivity in HCC cells. Knockdown of lncRNA H19 elevated sorafenib sensitivity by suppressing epithelial­mesenchymal transition (EMT) in HCC cells. H19 upregulated miR­675 expression. miR­675 inhibitor decreased the cell viability in sorafenib­treated HCC cells, while miR­675 overexpression had the opposite effect on the treated cells. When the cells were pretreated with miR­675 mimic, H19 siRNA did not alter the effect of miR­675 on sorafenib sensitivity. In conclusion, our study provides new clues for further clinical treatment of sorafenib­resistant liver cancer patients.