Di-2-pyridylketone 4,4-Dimethyl-3-thiosemicarbazone (Dp44mT) Overcomes Multidrug Resistance by a Novel Mechanism Involving the Hijacking of Lysosomal P-Glycoprotein (Pgp)
Di-2-pyridylketone 4,4-Dimethyl-3-thiosemicarbazone (Dp44mT) Overcomes Multidrug Resistance by a Novel Mechanism Involving the Hijacking of Lysosomal P-Glycoprotein (Pgp)
复制标题
DOI：
10.1074/jbc.m114.631283
复制
发表时间：
2015-04-10
影响因子：
4.8
通讯作者：
Richardson, Des R.
中科院分区：
文献类型：
--
作者：
Jansson, Patric J.;Yamagishi, Tetsuo;Richardson, Des R.
多药耐药(MDR)是癌症治疗的主要障碍。超过一半的人类癌症表达多药耐药P-糖蛋白(Pgp)，这与预后不良有关。有趣的是，通过一种未知的机制，一些药物在耐药肿瘤细胞中比它们的药物敏感的同类药物具有更大的活性。在这里，我们研究了新型抗肿瘤药物二-2-吡啶酮4，4-二甲基-3-氨基硫脲(Dp44mT)是如何克服MDR的。四种不同的细胞类型被用来评估Pgp增强的溶酶体靶向药物克服MDR的效果。为了评估Dp44mT如何克服耐药性的机制，细胞研究使用了Pgp抑制剂、Pgp沉默、溶酶促性剂、增殖分析、免疫印迹、Pgp-ATPase活性分析、放射性标记的药物摄取/效应、罗丹明123保留试验、溶酶体膜通透性评估和DCF(2‘，7’-二氯荧光素)氧化还原研究。采用BALB/c nu/nu小鼠移植瘤模型，研究了Dp44mT在表达Pgp的多药耐药细胞和药物敏感细胞中的抗肿瘤活性和选择性。我们证明了Dp44mT是通过溶酶体PGP药物泵转运的，导致溶酶体靶向Dp44mT，从而增强了MDR细胞的细胞毒性。溶酶体Pgp和pH是增加Dp44mT介导的溶酶体损伤和随后的耐药细胞细胞毒性的关键，Dp44mT被证明是Pgp底物。事实上，依赖于Pgp的溶酶体损伤和Dp44mT的细胞毒性可被Pgp抑制剂、Pgp沉默或使用溶酶体亲和性碱基提高溶酶体pH而取消。在体内，Dp44mT有效地靶向化疗耐药的人Pgp表达的异种移植瘤相对于不表达Pgp的小鼠肿瘤。这项研究强调了一种新的PGP劫持策略，即独特的二吡啶硫代氨基硫脲系列通过利用溶酶体Pgp转运活性来克服MDR。
Multidrug resistance (MDR) is a major obstacle in cancer treatment. More than half of human cancers express multidrug-resistant P-glycoprotein (Pgp), which correlates with a poor prognosis. Intriguingly, through an unknown mechanism, some drugs have greater activity in drug-resistant tumor cells than their drug-sensitive counterparts. Herein, we investigate how the novel anti-tumor agent di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT) overcomes MDR. Four different cell types were utilized to evaluate the effect of Pgp-potentiated lysosomal targeting of drugs to overcome MDR. To assess the mechanism of how Dp44mT overcomes drug resistance, cellular studies utilized Pgp inhibitors, Pgp silencing, lysosornotropic agents, proliferation assays, immunoblotting, a Pgp-ATPase activity assay, radiolabeled drug uptake/effittx, a rhodamine 123 retention assay, lysosomal membrane permeability assessment, and DCF (2',7'-dichlorafluorescin) redox studies. Anti-tumor activity and selectivity of Dp44mT in Pgp-expressing, MDR cells versus drug-sensitive cells were studied using a BALB/c nu/nu xenograft mouse model. We demonstrate that Dp44mT is transported by the lysosomal Pgp drug pump, causing lysosomal targeting of Dp44mT and resulting in enhanced cytotoxicity in MDR cells. Lysosornal Pgp and pH were shown to be crucial for increasing Dp44mT-mediated lysosomal damage and subsequent cytotoxicity in drug-resistant cells, with Dp44mT being demonstrated to be a Pgp substrate. Indeed, Pgp-dependent lysosomal damage and cytotoxicity of Dp44mT were abrogated by Pgp inhibitors, Pgp silencing, or increasing lysosomal pH using lysosomotropic bases. In vivo, Dp44mT potently targeted chemotherapy-resistant human Pgp-expressing xenografted tumors relative to non-Pgp-expressing tumors in mice. This study highlights a novel Pgp hijacking strategy of the unique dipyridylthiosenticarbazone series of thiosemicarbazones that overcome MDR via utilization of lysosomal Pgp transport activity.