Disulfiram metabolites permanently inactivate the human multidrug resistance P-glycoprotein
Disulfiram metabolites permanently inactivate the human multidrug resistance P-glycoprotein
复制标题
DOI：
10.1021/mp049917l
复制
发表时间：
2004-11-01
影响因子：
4.9
通讯作者：
Clarke, David M.
中科院分区：
文献类型：
--
作者：
Loo, Tip W.;Bartlett, M. Claire;Clarke, David M.
人类多药耐药P-糖蛋白(P-gp)利用ATIP将多种结构无关的细胞毒性化合物转运出细胞外。P-gp在肠、肾、血脑/睾丸屏障等器官和某些肿瘤细胞中的相对高表达可能会影响癌症或艾滋病/HIV患者的化疗。在化疗中使用非共价抑制剂很难抑制P-gp，因为相对较高水平的抑制剂有严重的副作用。抑制P-gp的另一种方法是对NBDS中的半胱氨酸残基进行共价修饰。在这项研究中，我们测试了目前用于治疗慢性酒精中毒的药物双硫兰的代谢物是否可以抑制P-gp。结果表明，二硫仑代谢产物S-N，N-二乙基硫代氨基甲酸亚砜和S-N，N-二乙基硫代氨基甲酸砜对维拉帕米刺激的P-gp的ATPase活性有抑制作用，其IC50值分别为9和4.8mU。同样，S-N，N-二乙基硫代氨基甲酸亚砜和S-N，N-二乙基硫代氨基甲酸亚砜对乙醛脱氢酶活性有抑制作用，其IC50值分别为3.2mU和1.7mU。添加还原化合物二硫苏糖醇不能逆转代谢产物对P-gp的抑制作用。然后，我们确定哪些内源性半胱氨酸残基负责在暴露于双硫仑代谢物后抑制P-gp活性。对含有一个半胱氨酸残基的P-gp突变体的处理表明，失活主要是由于Nbd2中Cys1074的修饰。这些结果表明，双硫仑的代谢产物可以共价灭活P-gp。药物转运体的共价修饰是抑制其在化疗过程中活性的有效途径。
The human multidrug resistance P-glycoprotein (P-gp) uses ATIP to transport a wide variety of structurally unrelated cytotoxic compounds out of the cell. The relatively high expression of P-gp in organs such as the intestine, kidney, blood-brain/testes barrier and in some tumor cells can compromise chemotherapy treatments for patients with cancer or AIDS/HIV. It has been difficult to inhibit P-gp during chemotherapy with noncovalent inhibitors because the relatively high levels of inhibitors have severe side effects. An alternative approach to inhibit P-gp would be to covalently modify cysteine residues within the NBDs. In this study, we tested whether metabolites of disulfiram, a drug currently used to treat chronic alcoholism, could inhibit P-gp. We show that the disulfiram metabolites, S-methyl N,N-diethylthiocarbamate sulfoxide and S-methyl N,N-diethylthiocarbamate sulfone inhibited the verapamil-stimulated ATPase activity of P-gp with IC50 values (concentrations that result in 50% inhibition of activity) of 9 and 4.8 mu M, respectively. Similarly, S-methyl N,N-diethylthiocarbamate sulfoxide and S-methyl N,N-diethylthiocarbamate sulfone inhibited the activity of aldehyde dehydrogenase with IC50 values of 3.2 and 1.7 mu M, respectively. Inhibition of P-gp by the metabolites was not reversed by addition of the reducing compound, dithiothreitol. We then determined which endogenous cysteine residue was responsible for inhibiting P-gp activity after exposure to the disulfiram metabolites. Treatment of P-gp mutants containing a single cysteine residue showed that inactivation was primarily due to modification of Cys1074 in NBD2. These results indicate that metabolites of disulfiram can covalently inactivate P-gp. Covalent modification of drug transporters could be a useful approach for inhibiting their activities during chemotherapy.