The aim of the present study was to establish, characterize and elucidate the potential mechanisms of acquired gefitinb resistance, using the A549 human lung cancer cell line. A gefitinib-resistant A549 sub-clone was established by exposure to escalating gefitinib concentrations over a period of 16-24 months. Half maximal inhibitory concentration (IC50) values were quantified using a real time cytotoxicity assay. The expression profiles of the parent and resistant sub-clone A549 cells were detected using the µParaflo® Microfluidics Biochip microRNA (miRNA) Microarray. The ArrayPro software was used to analyze the differential expression levels of the miRNA, and bioinformatics software was used to predict the potential target genes of the differentially expressed miRNAs. Quantitative polymerase chain reaction (qPCR) was used to confirm the results of the miRNA microarray. A miRNA mimic was transfected into the gefitinib-resistant cells, in order to predict target gene interaction effects, following gefitinib treatment. Protein expression level differences were confirmed by western-blot analysis. Real time cytotoxicity assays revealed a 3-fold increase in the IC50 values of the gefitinib-resistant sub-clones, as compared with the parent cells. There were marked morphological differences between the parent and resistant cells. In the microarray analysis, the gefitinib-resistant sub-clones had 25 upregulated and 18 downregulated miRNAs, as compared with the parent cells. The qPCR revealed that miR-7 was significantly downregulated, which was concordant with the results of the microarray. The results of the present study suggest that miR-7 may significantly improve the sensitivity of cancer cells to gefitinib. The data presented in the present study provides an experimental basis and theory that miRNAs may be involved in acquired gefitinib-resistance of lung adenocarcinoma, and miR-7 may have potential clinical effects in the reversal of drug resistance.

Background and Aims: Lipid accumulation is the major characteristic of non-alcoholic fatty liver disease, the prevalence of which continues to rise. We aimed to investigate the effects and mechanisms of icaritin on lipid accumulation. Methods: Cells were treated with icaritin at 0.7, 2.2, 6.7, or 20 µM for 24 h. The effects on lipid accumulation in L02 and Huh-7 cells were detected by Bodipy and oil red O staining, respectively. Mitochondria biogenesis of L02 cells was detected by MitoTracker Orange staining. Glucose uptake and adenosine triphosphate content of 3T3-L1 adipocytes and C2C12 myotubes were detected. The expression levels of proteins in the adenosine 5′-monophosphate-activated protein kinase (AMPK) signaling pathway, biomarkers of autophagy, and mitochondria biogenesis were measured by western blotting. LC3 puncta were detected by immunofluorescence. Results: Icaritin significantly attenuated lipid accumulation in L02 and Huh-7 cells and boosted the mitochondria biogenesis of L02 cells. Icaritin enhanced glucose uptake, decreased adenosine triphosphate content, and activated the AMPK signaling pathway in 3T3-L1 adipocytes and C2C12 myotubes. Icaritin boosted autophagy and also enhanced the initiation of autophagic flux in 3T3-L1 preadipocytes and C2C12 myoblasts. However, icaritin decreased autophagy and promoted mitochondria biogenesis in 3T3-L1 adipocytes and C2C12 myotubes. Conclusions: Icaritin attenuates lipid accumulation by increasing energy expenditure and regulating autophagy by activating the AMPK pathway.

SrFe12−xNbxO19 (x = 0.00–0.15) was here synthesized by a conventional solid-state reaction method. Thermogravimetry and differential scanning calorimetry curves revealed the sample reactions at four temperature ranges, and the optimal reaction stability was obtained at 1240 °C. A single-phase polycrystalline form of SrFe12O19 was obtained until the substitution reached 0.09, and the average crystallite size was found to be in the range of 44.21–60.02 nm. According to Fourier-transform infrared spectra, the formation of Fe–O bonds occurred at 69 and 450 cm−1 in the M-type ferrite, while Raman spectra revealed that all the peaks in the sample corresponded to Raman vibration modes and M-type structures. Through the shift of the peaks, it is speculated that Nb5+ enters into the lattice. The hysteresis loops of the samples were measured by vibrating-sample magnetometry, and the calculated results demonstrated that the coercivity increased with increases in the doping amount (686.3 Oe). At the same time, the saturation magnetization remained at a large value (>72.49 emu/g), which has rarely been reported.

Citric acid is a small-molecule organic acid, which can be used as an inhibitor for the flotation of Mg 2+ activated quartz. Methods such as flotation experiments, zeta potential, FTIR qualitative and quantitative calculations, and solution chemistry calculations were used in this study to conduct systematic research to study activation and inhibition mechanisms. The results show that adding only a quarter of citric acid under the optimal conditions of Mg 2+ activated quartz produces the best inhibitory effect. Mg 2+ and citric acid affect the zeta potential of the quartz surface in the zeta potential experiment. FTIR qualitatively found that under the action of Mg 2+ , sodium oleate was adsorbed on the quartz surface in the form of physical adsorption; quantitative analysis clearly explained that after the chemical reaction between citric acid and Mg 2+ , it desorbed from the quartz surface into the water system. According to the chemical calculation of the solution during the flotation process, it is found that the reaction product of citric acid and Mg 2+ has no inhibitory effect; only the amount of Mg 2+ is consumed, thereby reducing the number of activating factors and cutting off the medium of sodium oleate adsorbed on the surface of the quartz.

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