Impact of chrysosplenetin, per se or in combination with artemisinin, on breast cancer resistance protein (Bcrp)/ABCG2 mRNA expression levels in mice small intestine

ABSTRACT

ABSTRACT Our previous work revealed that chrysosplenetin in combination with artemisinin inhibited in vivo P-glycoprotein (P-gp, one of classic multi-drug resistance proteins) mediated digoxin transportation activity by reversing the upregulated P-gp/Mdr1 mRNA expression levels by artemisinin. Therefore, chrysosplenetin might be a potential artemisinin-resistance reversal agent as a P-gp inhibitor. But it still remains unknown if chrysosplenetin has an impact on another pivotal multi-drug resistance protein, breast cancer resistance protein (Bcrp), which is co-expressed with P-gp in apical membrane of intestinal epithelial cell and overlaps some of the substrates and inhibitors. This study, therefore, further addressed the impact of chrysosplenetin, per se or in combination with artemisin, on Bcrp/ABCG2 mRNA expression levels in mice small intestine determined by western blot and real time-quantitative polymerase chain reaction (RT-qPCR) assay. The drugs were intragastrically administrated once per day for 7 days. Novobiocin, a known Bcrp inhibitor, was observed to have no impact on Bcrp/ABCG2 levels with or without artemisinin versus vehicle. Interestingly, artemisinin alone attenuated Bcrp level while chrysosplenetin alone increased it (p < 0.05). Relative mRNA level was significantly decreased when co-used with artemisinin and chrysosplenetin in ratio of 12 (p < 0.05). The discrepant results for chrysosplenetin on Bcrp/ABCG2 mRNA expressions might be closely related to the transcriptional or posttranscriptional regulation.