title: Comprehensive assessment of Cucurbitacin E related hepatotoxicity and drug-drug interactions involving CYP3A and P-glycoprotein.
abstract: BACKGROUND
  Cucurbitacin E (CuE), a tetracyclic triterpenoid isolated from Cucurbitaceae, possesses many pharmacological activities especially anti-cancer.
  
  
  OBJECTIVE
  The aim of this investigation was to comprehensively assess CuE related hepatotoxicity and potential drug-drug interactions involving CYP3A and P-glycoprotein (P-gp).
  
  
  METHODS
  Four common cytotoxicity assays (MTS, SRB, NRU and apoptosis assays) were used to evaluate the hepatotoxicity of CuE in human hepatocellular carcinoma HepG2 cells. Human and rat liver microsomes incubation system, Caco-2 transport model and 3D organoids model were used to investigate the effects of CuE on CYP3A and P-gp in vitro. The oral pharmacokinetics of indinavir was employed to evaluate the effects of CuE on CYP3A and P-gp in vivo.
  
  
  RESULTS
  CuE induced the HepG2 apoptosis and exhibited acute cytotoxicity in MTS, SRB, and NRU assays with IC50value at 15.98µM, 0.31µM, and 1.11µM, respectively. Moreover, CuE not only presented mechanism-based inhibition on human CYP3A4, but also decreased the efflux ratio of digoxin (P-gp substrate) across Caco-2 cell monolayers in vitro. Furthermore, CuE significantly inhibited the transport of Rh123 into 3D organoids, which was caused by the inhibition on P-gp. In Sprague-Dawley rat studies in vivo, acute administration of CuE significantly increased the maximum serum concentration (Cmax) and area under the concentration-time curve (AUC) of indinavir. In contrast, CuE treatment for three consecutive days significantly decreased indinavir Cmaxand AUC in rats.
  
  
  CONCLUSIONS
  These studies demonstrated that CuE has strong hepatotoxicity, and CuE presents potent inhibition on both CYP3A and P-gp activities in vitro. In animal in vivo studies, CuE induces CYP3A and P-gp after a long-term treatment but inhibits the activities of CYP3A and P-gp after an acute dosing. Therefore, CuE as a dual functional regulator of both CYP3A and P-gp may cause complex drug-drug interactions.
authors.affiliation: Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Lu
authors.affiliation: Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China.
authors.forename: Yuanjin
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China.
authors.forename: Min
authors.initials: M
authors.lastname: Sun
authors.affiliation: Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China; Center for Cancer and Stem Cell Biology, Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX, USA.
authors.forename: Mingyao
authors.initials: M
authors.lastname: Liu
authors.affiliation: Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, China. Electronic address: usxinwang@gmail.com.
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B / Q000378:metabolism*; D000818:Animals; D018938:Caco-2 Cells / Q000187:drug effects; D056486:Chemical and Drug Induced Liver Injury / Q000503:physiopathology*; D051544:Cytochrome P-450 CYP3A / Q000378:metabolism*; D004347:Drug Interactions; D006801:Humans; D008099:Liver / Q000378:metabolism*; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014315:Triterpenes / Q000378:metabolism* / Q000633:toxicity*
chemical_list: D018435:ATP Binding Cassette Transporter, Subfamily B; D014315:Triterpenes; D051544:Cytochrome P-450 CYP3A; C102326:cucurbitacin E
keywords: CYP3A; Cucurbitacin E; Drug-drug interactions; Hepatotoxicity; P-glycoprotein