Hu Xiaowen, Li Mengsiyu, Zhang Chunxue, Pang Shuguang
Department of Endocrinology, Jinan Central Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.
Department of Infectious Diseases, Jinan Central Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.
Int J Endocrinol. 2021 Feb 15;2021:8867218. doi: 10.1155/2021/8867218. eCollection 2021.
Metformin, as a first-line treatment for diabetes, interacts with many protein kinases and transcription factors which affect the expression of downstream target genes governing drug metabolism. Sulfotransferase, SULT2A1, one phase II metabolic enzyme, sulfonates both xenobiotic and endobiotic compounds to accelerate drug excretion. Herein, we designed experiments to investigate the effects and mechanisms of metformin on SULT2A1 expression in vitro.
The hepatocellular carcinoma cell line, HepaRG, was cultured with different concentrations of metformin. The cell viability was measured using CCK8 kit. HepaRG was used to evaluate the protein expression of pregnane X receptor (PXR), the constitutive androstane receptor (CAR), SULT2A1, AMP-activated protein kinase (AMPK), and phosphorylation of AMPK (p-AMPK), respectively, at different concentrations of metformin with or without rifampin (human PXR activator) and CITCO (human CAR activator). The coregulators with CAR on SULT2A1 promoter response elements have also been characterized.
We showed that metformin did not affect the basic expression of SULT2A1 but could suppress the expression of SULT2A1 induced by the activator of human CAR. Investigations revealed that metformin which could block CAR nuclear translocation further suppress SULT2A1. In addition, we found that the prevented CAR transfer into the nucleus by metformin was partially an AMPK-dependent event.
The present study indicated that the activation of AMPK-CAR pathway mediated the suppression of SULT2A1 by metformin. Metformin may affect the metabolism and clearance of drugs which are SULT2A1 substrates. The results that emerged from this work provide substantial insights into an appropriate medication in the treatment of diabetes patients.
二甲双胍作为糖尿病的一线治疗药物，可与多种蛋白激酶和转录因子相互作用，这些蛋白激酶和转录因子会影响调控药物代谢的下游靶基因的表达。磺基转移酶SULT2A1是一种II相代谢酶，可使外源性和内源性化合物磺化，以加速药物排泄。在此，我们设计实验以研究二甲双胍对体外SULT2A1表达的影响及其机制。
用不同浓度的二甲双胍培养肝癌细胞系HepaRG。使用CCK8试剂盒检测细胞活力。分别在有或无利福平（人PXR激活剂）和CITCO（人CAR激活剂）存在的情况下，用不同浓度的二甲双胍处理HepaRG，以评估孕烷X受体（PXR）、组成型雄烷受体（CAR）、SULT2A1、AMP激活的蛋白激酶（AMPK）以及AMPK的磷酸化（p-AMPK）的蛋白表达。还对CAR在SULT2A1启动子反应元件上的共调节因子进行了表征。
我们发现二甲双胍不影响SULT2A1的基础表达，但可抑制人CAR激活剂诱导的SULT2A1表达。研究表明，能阻断CAR核转位的二甲双胍可进一步抑制SULT2A1。此外，我们发现二甲双胍阻止CAR转移至细胞核的作用部分是一个依赖AMPK的事件。
本研究表明，AMPK-CAR途径的激活介导了二甲双胍对SULT2A1的抑制作用。二甲双胍可能会影响作为SULT2A1底物的药物的代谢和清除。这项工作得出的结果为糖尿病患者的合理用药提供了重要见解。
