miR-188-5p inhibits proliferation, migration, and invasion in gallbladder carcinoma by targeting Wnt2b and Smad2.

Gallbladder carcinoma (GBC) commonly occurs in gastrointestinal malignancy and has the fifth highest mortality rate among gastrointestinal malignancy. Recently, miR-188-5p, a small noncoding RNA, has been implicated in various types of cancer such as nasopharyngeal carcinoma, oral squamous cell carcinoma, liver cancer, and prostate cancer. However, the effect of miR-188-5p on GBC remains unclear. Here, we demonstrated that miR-188-5p was downregulated in GBC tissues, and downregulation of miR-188-5p correlated with larger tumor size, lymph node metastasis, and extensive metastasis. In addition, the overall survival time of patients with higher miR-188-5p expression was significantly longer than that of patients with low-miR-188-5p expression. Moreover, downregulation of miR-188-5p promoted the proliferation, migration, and invasion of GBC cells, while its overexpression inhibited cell invasion and induced cell apoptosis, and arrested GBC growth in vivo. Importantly, miR-188-5p-dependent tumorigenesis was correlated with Wnt/ß-catenin signaling and p-38/JNK signaling. In conclusion, miR-188-5p plays a direct role in GBC tumorigenesis. Our study suggests that miR-188-5p could serve as a novel diagnosis marker and therapeutic target in GBC.

LC-MS/MS determination and pharmacokinetic study of bergenin, the main bioactive component of Bergenia purpurascens after oral administration in rats.

Bergenin, a C-glucoside of 4-O-methyl gallic acid from Bergenia purpurascens, is a naturally antitussive and expectorant agent. A rapid and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the determination of the active component-bergenin, in rat plasma after oral administration of aqueous B. purpurascens extract. The plasma samples were pretreated by protein precipitation with acetonitrile and chromatographic separation was achieved on a Diamonsil® C18 column (150 mm×4.6 mm, 5 µm) with isocratic elution using a mobile phase consisting of water-methanol (30:70, v/v) at a flow rate of 0.6 mL/min. The detection was accomplished by a triple-quadrupole tandem mass spectrometer in multiple-reaction monitoring (MRM) scanning via an electrospray ionization (ESI) source operating in the negative mode. The optimized mass transition ion-pairs (m/z) for quantitation were 327.3/192.0 for bergenin, and 431.1/311.1 for IS. The time for each analysis run was only 3.5 min between injections. The calibration curve exhibited good linearity (r2>0.99) over a range of 1.00-2000 ng/mL for bergenin. The lower limit of quantitation (LLOQ) was 1.00 ng/mL. The intra- and inter-day precisions were no more than 11.8%, and relative errors (RE) were within the range of 0.0-4.4%. The validated method was successfully applied to investigate the pharmacokinetics of bergenin after oral administration of B. purpurascens extract in rats.

Mechanisms mediating the cardioprotective effects of rapamycin in ischaemia-reperfusion injury.

1. In the present study, the temporal and concentration-dependent cardioprotective effects of rapamycin against ischaemia-reperfusion (I/R) injury, as well as the underlying mechanisms, were investigated. 2. Rat Langendorff-perfused isolated hearts were exposed to 40 min global ischaemia followed by 120 min reperfusion. Hearts were perfused with different concentrations of rapamycin before and after ischaemia. Myocardial injury was assessed in terms of infarct size and the release of lactate dehydrogenase (LDH) and creatine kinase (CK). The phosphorylation of Akt, extracellular signal-regulated kinase (ERK) 1/2 and endothelial nitric oxide synthase (eNOS) was determined at the end of reperfusion. 3. When administered prior to ischaemia, 25, 50 and 100 nmol/L rapamycin significantly reduced infarct size compared with control (40.1 ± 1.5, 26.3 ± 4.1 and 21.2 ± 3.4 vs 52.5 ± 4.5%, respectively) without affecting the recovery of ventricular function. No reduction in infarct size was observed when 50 nmol/L rapamycin was administered 10 or 120 min into the reperfusion period. 4. Rapamycin (50 nmol/L) enhanced the phosphorylation of Akt kinase but did not affect the phosphorylation of ERK1/2 or eNOS at the end of reperfusion. The cardioprotective effect of rapamycin was blocked by the phosphatidylinositol 3-kinase (Akt) inhibitor LY294002 (15 nmol/L). 5. In conclusion, rapamycin mediates cardioprotection prior to ischaemia and after reperfusion. This protection may involve activation of the phosphatidylinositol 3-kinase pathway.