Development of a UHPLC-MS/MS method for the quantification of ilaprazole enantiomers in rat plasma and its pharmacokinetic application / 药物分析学报

In Korea and China, ilaprazole is a widely used proton pump inhibitor in the treatment of gastric ulcers. In this study, a specific and sensitive LC-MS/MS method has been developed and validated for the quantification of ilaprazole enantiomers in the rat plasma, using R-lansoprazole as the internal standard. The enantioseparation was achieved on a CHIRALPAK AS-RH column (4.6 mm × 150 mm, i.d. 5μm), with a mobile phase composed of 10 mM ammonium acetate aqueous solution and acetonitrile (60:40, V/V), at a flow-rate of 0.5 mL/min. The method was validated over the concentration range of 0.5-300 ng/mL for both, R- and S -ilaprazole. The lower limit of quantification was 0.5 ng/mL for both enantiomers. The relative standard deviation (RSD) of intra- and inter-day precision of R-ilaprazole and S-ilaprazole was less than 10.9％, and the relative error accuracy (RE) ranged from -0.5％-2.0％. Finally, the method was successfully evaluated in rats in a stereoselective pharmacokinetic study of the ilaprazole racemate.

Upregulation of miR-489-3p and miR-630 inhibits oxaliplatin uptake in renal cell carcinoma by targeting OCT2

Renal cell carcinoma (RCC) is one of the most common malignant tumors affecting the urogenital system, accounting for 90% of renal malignancies. Traditional chemotherapy options are often the front-line choice of regimen in the treatment of patients with RCC, but responses may be modest or limited due to resistance of the tumor to anticarcinogen. Downregulated expression of organic cation transporter OCT2 is a possible mechanism underlying oxaliplatin resistance in RCC treatment. In this study, we observed that miR-489-3p and miR-630 suppress OCT2 expression by directly binding to the OCT2 3'-UTR. Meanwhile, 786-O-OCT2-miRNAs stable expression cell models, we found that miRNAs could repress the classic substrate 1-methyl-4-phenylpyridinium (MPP), fluorogenic substrate ,-dimethyl-4-(2-pyridin-4-ylethenyl) aniline (ASP), and oxaliplatin uptake by OCT2 both and in xenografts. In 33 clinical samples, miR-489-3p and miR-630 were significantly upregulated in RCC, negatively correlating with the OCT2 expression level compared to that in adjacent normal tissues, using tissue microarray analysis and qPCR validation. The increased binding of c-Myc to the promoter of pri-miR-630, responsible for the upregulation of miR-630 in RCC, was further evidenced by chromatin immunoprecipitation and dual-luciferase reporter assay. Overall, this study indicated that miR-489-3p and miR-630 function as oncotherapy-obstructing microRNAs by directly targeting OCT2 in RCC.