Cisplatin increases carboxylesterases through increasing PXR mediated by the decrease of DEC1

cis-Diamminedichloroplatinum(CDDP)is widely used for the treatment of various solid cancers.Here we reported that CDDP increased the expression and enzymatic activities of carboxylesterase 1(CES1)and carboxylesterase 2(CES2),along with the upregulation of pregnane X receptor(PXR)and the downregulation of differentiated embryonic chondrocyte-expressed gene 1(DEC1)in human hepatoma cells,primary mouse hepatocytes,mouse liver and intestine.The overexpression or knockdown of PXR alone upregulated or downregulated the CES1 and CES2 expression,respectively.The increases in CES1 and CES2 expression levels induced by CDDP abolished or enhanced by PXR knockdown or overexpression,implying that CDDP induces carboxylesterases through the activation of PXR.Likewise,the overexpression or knockdown of DEC1 alone significantly decreased or increased PXR and its targets.Moreover,the increases of PXR and its targets induced by CDDP were abolished or alleviated by the overexpression or knockdown of DEC1.The overexpression or knockdown of DEC1 affected the response of PXR to CDDP,but not vice versa,suggesting that CDDP increases carboxylesterases by upregulating PXR mediated by the decrease of DEC1.In addition,CDDP did not increase DEC1 mRNA degradation but suppressed DEC1 promoter reporter activity,indicating that it suppresses DEC1 transcriptionally.The combined use of CDDP and irinotecan had a synergistic effect on two cell lines,especially when CDDP was used first.

Bioactive neolignans and lignans from the roots of Paeonia lactiflora

Two new neolignans and one new lignan(1-3)were obtained from the roots of Paeonia lactiflora.Their structures were unambiguously elucidated based on extensive spectroscopic analysis,single-crystal X-ray crystallography,and the calculated and experimental electronic circular dichroism(ECD)spectra.Compound 1 was a racemic mixture and successfully resolved into the anticipated enantiomers via chiral-phase HPLC.Compound 3 demonstrated moderate inhibitory activity against human carboxylesterase 2A1(hCES2Al)with an IC_(50) value of 7.28±0.94 μmol·L^(-1).