Plant natural product plumbagin presents potent inhibitory effect on human cytochrome P450 2J2 enzyme.

BACKGROUND: Cytochrome P450 2J2 (CYP2J2) is not only highly expressed in many kinds of human tumors, but also promotes tumor cell growth via regulating the metabolism of arachidonic acids. CYP2J2 inhibitors can significantly reduce proliferation, migration and promote apoptosis of tumor cells by inhibiting epoxyeicosatrienoic acids (EETs) biosynthesis. Therefore screening CYP2J2 inhibitors is a significant way for the development of anti-cancer drug. PURPOSE: The aim of this study was to identify a new CYP2J2 inhibitor from fifty natural compounds obtained from plants. STUDY DESIGN: CYP2J2 inhibitor was screened from a natural compounds library and further the inhibitory manner and mechanism were evaluated. Its cytotoxicity against HepG2 and SMMC-7721 cell lines was also estimated. METHODS: The inhibitory effect was evaluated in rat liver microsomes (RLMs), human liver microsomes (HLMs) and recombinant CYP2J2 (rCYP2J2), using astemizole as a probe substrate and inhibitory mechanism was illustrated through molecular docking. The cytotoxicity was detected using SRB. RESULTS: In all candidates, plumbagin showed the strongest inhibitory effect on the CYP2J2-mediated astemizole O-demethylation activity. Further study revealed that plumbagin potently inhibited CYP2J2 activity with IC50 value at 3.82 µM, 3.37 µM and 1.17 µM in RLMs, HLMs and rCYP2J2, respectively. Enzyme kinetic studies showed that plumbagin was a mixed-type inhibitor of CYP2J2 in HLMs and rCYP2J2 with Ki value of 1.88 µM and 0.92 µM, respectively. Docking data presented that plumbagin interacted with CYP2J2 mainly through GLU 222 and ALA 223. Moreover, plumbagin showed strongly cytotoxic effects on hepatoma cell lines, such as HepG2 and SMMC-7721, with lower toxicity on rat primary hepatocytes. Plumbagin had no effect on the protein expression of CYP2J2 in HepG2 and SMMC-7721, while down-regulated the mRNA level of anti-apoptosis protein Bcl-2. CONCLUSION: This study found out a new CYP2J2 inhibitor plumbagin from fifty natural compounds. Plumbagin presented a potential of anti-cancer pharmacological activity.

CRISPR knockout rat cytochrome P450 3A1/2 model for advancing drug metabolism and pharmacokinetics research.

Cytochrome P450 (CYP) 3A accounts for nearly 30% of the total CYP enzymes in the human liver and participates in the metabolism of over 50% of clinical drugs. Moreover, CYP3A plays an important role in chemical metabolism, toxicity, and carcinogenicity. New animal models are needed to investigate CYP3A functions, especially for drug metabolism. In this report, Cyp3a1/2 double knockout (KO) rats were generated by CRISPR-Cas9 technology, and then were characterized for viability and physiological status. The Cyp3a1/2 double KO rats were viable and fertile, and had no obvious physiological abnormities. Compared with the wild-type (WT) rat, Cyp3a1/2 expression was completely absent in the liver of the KO rat. In vitro and in vivo metabolic studies of the CYP3A1/2 substrates indicated that CYP3A1/2 was functionally inactive in double KO rats. The Cyp3a1/2 double KO rat model was successfully generated and characterized. The Cyp3a1/2 KO rats are a novel rodent animal model that will be a powerful tool for the study of the physiological and pharmacological roles of CYP3A, especially in drug and chemical metabolism in vivo.

[Factors influencing the temperature-sensing accuracy of ablation catheters].

Factors influencing the temperature-sensing accuracy of an ablation catheter are analyzed, in this paper, from the two aspects of the thermocouple temperature sensor, which are the TC length and the TC hole's diameter of the ablation electrode. Meanwhile, differences between products from different companies are given too.

[Development of an electrolytically-detachable microcoil for intracranial aneurysms].

An electrolytically-detachable microcoil is introduced here in the paper. The testing results indicate that, the microcoils have stable mechanical properties, clear radiographic images and fine insulation performance. Their detaching time varies from 30s to 200s when voltage changes from 2V to 5V.

[Finite element analysis and fatigue tests for nitinol vascular stents].

This essay is to make brief comments on the Nitinol vascular stents fatigue lifetime requirements, finite element analysis and fatigue lifetime tests etc.

[Nitinol alloy's applications in cerebral interventional devices].

With the development of cerebral interventional medical devices, Nitinol alloy has been widely used in clinical fields as a good biomaterial. This essay is to make brief comments on Nitinol alloy's present development, its material characteristics, medical basic researches, and applications in cerebral interventional devices.

[Research progresses in endovascular stent biomaterials].

This essay is to make brief comments on the physical characteristics, biocompatibility, corrosion resistance, clinical information, existent problems of endovascular stent biomaterials and the developing tendency in future.