ABSTRACT
OBJECTIVE： To study the effects of Aconitum carmichaelii water extract on the expression of 3 kinds of efflux transporters and 3 kinds of tight junction proteins as well as their genes in duodenum tissues of rats. METHODS： Thirty-two SD male rats were randomly divided into normal group， A. carmichaelii water extract low-dose， medium-dose and high-dose groups [0.45， 0.9， 1.8 g/（kg·d）， by crude drug]， with 8 rats in each group. They were given water and relevant liquid 0.1 mL/kg intragastrically for consecutive 7 d. After last administration， the duodenal segments of rats were collected. Western blotting assay was used to detect the expression of efflux transporters as P-glycoprotein （P-gp）， breast cancer resistance protein （Bcrp）， multidrug resistance protein 2 （Mrp2） as well as tight junction proteins as Claudin-1， Occludin and ZO-1. mRNA expression of 6 kinds of proteins relevant gene were determined by qRT-PCR respectively. RESULTS： Compared with normal group， the protein expression of P-gp， Mrp2， Bcrp， Claudin-1， Occludin and ZO-1 in duodenum of rats were increased significantly in A. carmichaelii water extract groups （P＜0.01）. mRNA expression of P-gp in A. carmichaelii water extract groups， mRNA expression of Bcrp in A. carmichaelii water extract low-dose and high-dose groups as well as mRNA expression of Claudin-1 in A. carmichaelli water extract medium-dose and high-dose groups were increased significantly， with statistical significance （P＜0.05 or P＜0.01）. There was no statistical significance in mRNA expression of other genes （P＞0.05）. CONCLUSIONS： A. carmichaelii water extract can up-regulate the expression of 3 kinds of efflux transporters and 3 kinds of tight junction proteins at the level of mRNA and/or protein， thus may interact with other substrates of the aforementioned efflux transporters and drugs with cell bypass pathway as the main transport pathway. In clinical practice， adjustment of dosage may be considered in drug combination.
ABSTRACT
ABC efflux proteins are a kind of transporters mediating diversified endogenous and exogenous efflux protein substrates across the plasma membrane by depending on the chemical energy released by ATP hydrolysis. As a vitally important functional membrane, it is widely found in various tissues and organs. The drug changes the expressions and/or functions of the transport proteins, which will affect the disposal process of substrate drugs corresponding to transporters , and finally lead to the pharmacokinetic interactions. The efflux proteins take part in the absorption, distribution, metabolism and excretion of drugs, and mainly consist of P-glycoprotein(P-gp), multidrug resistance associated protein(MRP) and breast cancer resistance protein(BCRP). The induction effect or inhibition effect of drugs on efflux protein plays a greatly significant role in the drug interaction produced by the compatibility of traditional Chinese medicine, which may be one of the important mechanisms of the theory of seven features of compatibility. In this article, the effects of seven features of compatibility on the ABC efflux transporters were reviewed, in order to reveal the roles of efflux protein in the herb-pairs compatibility, and provide new ideas for the mechanism and rationality of herb compatibility.
Subject(s)
Humans , ATP-Binding Cassette Transporters , Metabolism , Drug Interactions , Medicine, Chinese Traditional , Multidrug Resistance-Associated Proteins , Metabolism , Plant Preparations , PharmacologyABSTRACT
Despite its good initial response and significant survival benefit in patients with castration-resistant prostate cancer (CRPC), taxane therapy inevitably encounters drug resistance in all patients. Deep understandings of taxane resistant mechanisms can significantly facilitate the development of new therapeutic strategies to overcome taxane resistance and improve CRPC patient survival. Multiple pathways of resistance have been identified as potentially crucial areas of intervention. First, taxane resistant tumor cells typically have mutated microtubule binding sites, varying tubulin isotype expression, and upregulation of efflux transporters. These mechanisms contribute to reducing binding affinity and availability of taxanes. Second, taxane resistant tumors have increased stem cell like characteristics, indicating higher potential for further mutation in response to therapy. Third, the androgen receptor pathway is instrumental in the proliferation of CRPC and multiple hypotheses leading to this pathway reactivation have been reported. The connection of this pathway to the AKT pathway has received significant attention due to the upregulation of phosphorylated AKT in CRPC. This review highlights recent advances in elucidating taxane resistant mechanisms and summarizes potential therapeutic strategies for improved treatment of CRPC.