ABSTRACT
This study aims to investigate the effect of down-regulation of miR-205-5p by transfection of miR-205-5p inhibitor on the sensitivity of HNE1/DDP cells to cisplatin (DDP) induced apoptosis and explore the underlying mechanism. qRT-PCR was used to detect the expression of miR-205-5p in HNE1 or HNE1/DDP cells. The expression level of miR-205-5p was analyzed after transfecting HNE1/DDP cells with miR-205-5p inhibitor. MTT assay was used to evaluate the inhibitory effect of DDP alone or in combination with miR-205-5p inhibitor on the proliferation of HNE1/DDP or HNE1 cells. Apoptosis of cells treated with miR-205-5p inhibitor alone or in combination with DDP (8 μmol·L-1) was assessed using flow cytometry with PI staining, with the nucleus was counterstained with DAPI staining. The expression of Bax, Bak, Mcl-1, or Bcl-2 was analyzed by Western blot. HNE1/DDP cells showed a high level of expression of miR-205-5p, and the expression of miR-205-5p was significantly decreased by transfection of miR-205-5p inhibitor. Down-regulation of miR-205-5p significantly increased the sensitivity of HNE1/DDP cells to DDP (P<0.05). Transfection of miR-205-5p inhibitor enhanced the sensitivity of HNE1/DDP cells to DDP induced apoptosis. Treatment of HNE1/DDP cells with miR-205-5p inhibitor combined with DDP (8 μmol·L-1) for 24 h resulted in an apoptotic rate of 28.93% ± 2.50%, significantly higher than that treated with miR-205-5p inhibitor (9.83% ± 1.31%) or DDP alone (10.83% ± 1.70%) (P<0.05). DAPI staining showed that HNE1/DDP cell nucleus became significantly condensed and fragmented in miR-205-5p inhibitor combined with DDP group. The combined group up-regulated the expression of Bax and down-regulated the expression of Bcl-2 in HNE1/DDP cells. Therefore, down-regulation of miR-205-5p can enhance the sensitivity of HNE1/DDP cells to cisplatin induced apoptosis, and the mechanism may involve up-regulation of Bax and down-regulation of Bcl-2 expression.
ABSTRACT
The present study was designed to investigate the effects of Laminaria japonica (Laminaria) on pharmacokinetics of glycyrrhetinic acid (GA) following oral administration of Liquorice extract in rats. Following oral administrations of single-dose and multi-dose Liquorice extract and Liquorice-Laminaria extract, respectively, plasma samples were obtained at various times and the concentrations of GA, liquiritigenin, and isoliquiritigenin were measured by LC-MS. The effects of Laminaria extract on pharmacokinetics of GA were also investigated, following single-dose and multidose of glycyrrhizic acid (GL). The effects of Laminaria extract on intestinal absorption of GA and GL were studied using the in situ single-pass intestinal perfusion model. The metabolism of GL to GA in the contents of small and large intestines was also studied. The results showed Liquorice-Laminaria extract markedly increased the plasma concentration of GA, accompanied by a shorter Tmax. Similar alteration was observed following multidose administration. However, pharmacokinetics of neither liquiritigenin nor isoliquiritigenin was affected by Laminaria. Similarly, Laminaria markedly increased concentration and decreased Tmax of GA following oral GL were observed. The data from the intestinal perfusion model showed that Laminaria markedly increased GL absorption in duodenum and jejunum, but did not affect the intestinal absorption of GA. It was found that Laminaria enhanced the metabolism of GL to GA in large intestine. In conclusion, Laminaria increased plasma exposures of GA following oral administration of liquorice or GL, which partly resulted from increased intestinal absorption of GL and metabolism of GL to GA in large intestine.