Blood exosome marker miRNA-30d-5p: Role and regulation mechanism in cell stemness and gemcitabine resistance of hepatocellular carcinoma.

BACKGROUND: Cancer stem cells (CSCs) are different from regular cancer cells because of their self-renewal feature and differentiation potential, which establishes the backbone of the vital role of CSCs in the progress and drug resistance of hepatocellular carcinoma (HCC). The objective of this study was to evaluate the effects of blood exosome-derived miRNA-30d-5p on the stemness and gemcitabine resistance of HCC cells and the underlying mechanisms. METHODS: The expression data of HCC-related miRNAs and mRNAs were downloaded from TCGA database and analyzed for differences. Employing the databases of starBase, TargetScan, miRDB, and mirDIP, we conducted target gene prediction upstream of mRNA. The expression of miRNA-30d-5p and SOCS3 mRNA was assayed by qRT-PCR, and the binding between them was validated by dual luciferase assay. CCK-8 was employed to evaluate cell viability and the IC50 value of gemcitabine. Cells were subjected to a sphere-forming assay to assess their ability to form spheres. Western blot was applied to evaluate the levels of cell surface marker proteins (Nanog, CD133, and Oct4) and exosome markers (CD9, CD81, and FLOT1). RESULTS: Bioinformatics analysis found that SOCS3 expression was down-regulated in HCC. qRT-PCR showed that SOCS3 expression was notably lower in HCC cell lines than in normal liver cell WRL68. At the cellular functional level, SOCS3 overexpression inhibited the viability, sphere-forming ability, stemness, and gemcitabine resistance of HCC cells. Bioinformatics analysis demonstrated that miRNA-30d-5p was the upstream regulator of SOCS3 and highly expressed in HCC tissues and cells. Dual luciferase assay demonstrated that miRNA-30d-5p could bind SOCS3. Rescue experiments showed that upregulating SOCS3 could reverse the effects of miRNA-30d-5p overexpression on the viability, sphere-forming ability, and gemcitabine sensitivity of HCC cells. CONCLUSIONS: Blood exosome-derived miRNA-30d-5p promoted the stemness and gemcitabine resistance of HCC cells by repressing SOCS3 expression. Hence, the miRNA-30d-5p/SOCS3 axis might be a therapeutic target for chemotherapy resistance and a feasible marker for the prognosis of HCC patients.

Molecular Dynamics Simulation of Surfactant Flooding Driven Oil-Detachment in Nano-Silica Channels.

Recovery of crude oil in rock nanopores plays an important role in the petroleum industry. In this work, we carried out molecular dynamics (MD) simulations to study the process of ionic surfactant solution driven oil-detachment in model silica (SiO2) nanochannels. Our MD simulation results revealed that the oil-detachment induced by the ionic surfactant flooding can be described by a three-stage process including the formation and delivery of surfactant micelles, the surfactant micelle disintegration-spread and migration on the oil-aggregate surface, and oil molecular aggregate deformation-to-detachment. A flooding from rear (FFR) phenomenon is revealed that the surfactant molecules tend to migrate to the rear bottom of the oil molecular aggregate caused by the water flow effect and hydration of polar head groups of surfactants, which facilitate the penetration of water molecules into the oil-rock interface, and the oil molecule detachment occurs at the rear bottom of the oil molecular aggregate. The present MD simulation results also indicate that the dodecyl benzenesulfonate (SDBS) has higher oil-driven efficiency than that of dodecyl trimethylammonium bromide (DTAB). The difference of oil displacement efficiency between the two surfactants is attributed to the hydration property of the polar head groups. Compared with the -N(CH3)3+ headgroup in DTAB, the bare O atom in the -SO3- group has a stronger H bond interaction with the surrounding water molecules. The stronger interaction between the headgroup of SDBS and the adjacent water molecule results in the surfactant migrating to the rear bottom of the oil molecules more quickly, thus accelerating the detachment of oil molecules.