Inhibition of Re Du Ning Injection on Enzyme Activities of Rat Liver Microsomes Using Cocktail Method

Objective Re Du Ning Injection （RDN）, a Chinese materia medica injection, is made from the extracts of LoniceraeJaponicae Flos, Gardeniae Fructus, and Artemisiae Annuae Herba. Since last decade, RDN has been widely used in China for the treatment of viral infection, fever, and inflammation. To assess the potential interacting of RDN with co-administered drugs, the inhibitory effects of RDN on the enzyme activities （CYP1A1, CYP1A2, CYP2C11, CYP2D1, and CYP3A1/2） of rat liver microsomes were investigated by a cocktail method. Methods A sensitive and specific LC-MS method capable of simultaneous quantification of five metabolites in rat liver microsomes was developed and validated. Then RDN （0.625%-1.0%） was incubated with rat liver microsomes and specific substrates. The enzyme activities were expressed as the formation rate of the specific metabolites of the substrates （pmol- mg. protein-1 . min-1）. Results RDN competitively inhibited the activities of CYP1A2 and CYP2C11, with inhibition constant （/~） values determined to be 0.18% and 0.63%, respectively. RDN exhibited the mixed inhibition on the activity of CYP2D1, with a K1 value of 0.15%. The activities of CYP1A1 and CYP3A1/2 were not markedly inhibited even by 1.0% RDN. Conclusion RDN could inhibit the rat enzyme activities of CYP1A2, 2Cll, and 2D1 in vitro with different inhibition modes, which is worthy of promoting safety and efficacy of RDN.

Potential therapeutic effect of epigenetic therapy on Ireatment-induced neuroendocrine prostate cancer

Although adenocarcinomas of the prostate are relatively indolent, some patients with advanced adenocarcinomas show recurrence of treatment-induced neuroendocrine prostate cancer, which is highly aggressive and lethal. Detailed biological features of treatment-induced neuroendocrine prostate cancer have not been characterized owing to limited biopsies/resections and the lack of a cellular model. In this study, we used a unique cellular model （LNCaP/NE1.8） to investigate the potential role of cancer stem cells in treatment-induced neuroendocrine prostate cancer with acquired resistance to hormonal therapy and chemotherapy. We also studied the role of cancer stem cells in enhancing invasion in treatment-induced neuroendocrine prostate cancer cells that recurred after long-term androgen-ablation treatment. Using an in vitro system mimicking clinical androgen-ablation, our results showed that the neuroendocrine-like subclone NE1.8 cells were enriched with cancer stem cells. Compared to parental prostate adenocarcinoma LNCaP cells, NE1.8 cells are more resistant to androgen deprivation therapy and chemotherapeutic agents and show increased cancer cell invasiveness. Results from this study also suggest a potential epigenetic therapeutic strategy using suberoylanilide hydroxamic acid, a histone deacetylase inhibitor, as a chemotherapeutic agent for therapy-resistant treatment-induced neuroendocrine prostate cancer cells to minimize the risk of prostate cancer recurrence and metastasis.

Determination of Protopine in Rat Brain Tissues by RRLC-ESI/Q-TOF-MS Method

Objective To analyse the quantification of protopine from Corydalis Decumbentis Rhizoma（CDR）extract in brain tissues of rats.Methods A rapid,sensitive,and accurate analytical method based on rapid resolution liquid chromatography（RRLC）coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry（Q-TOF-MS）was developed for the quantification of protopine in brain of rats.A simple liquid-liquid extraction process was employed for the sample preparation.Chromatographic separation was achieved using 1.8μm porous particle columns.Results The calibration curve of protopine was linear in the range of 12-897 ng/mL.The relative standard deviations of intra-and inter-day precision values were less than 10%.The extraction recoveries were 96.4%,99.6%,and 98.5%,for protopine at the concentration of 598.0,119.6,and 12.0 ng/mL,respectively,and internal standard（1.27μg/mL）was（98.60±0.02）%.Conclusion The validated method is successfully applied for the determination of protopine in brain tissue of rats after ig administration of CDR extract.