Bortolozzi Roberta, Viola Giampietro, Porcù Elena, Consolaro Francesca, Marzano Cristina, Pellei Maura, Gandin Valentina, Basso Giuseppe
Department of Women's and Children's Health, Oncohematology Laboratory, University of Padova, Padova, Italy. These authors contributed equally to this work.
Department of Women's and Children's Health, Oncohematology Laboratory, University of Padova, Padova, Italy.
Oncotarget. 2014 Aug 15;5(15):5978-91. doi: 10.18632/oncotarget.2027.
A phosphine copper(I) complex [Cu(thp)4][PF6] (CP) was recently identified as an efficient in vitro antitumor agent. In this study, we evaluated the antiproliferative activity of CP in leukemia cell lines finding a significant efficacy, especially against SEM and RS4;11 cells. Immunoblot analysis showed the activation of caspase-12 and caspase-9 and of the two effector caspase-3 and -7, suggesting that cell death occurred in a caspase-dependent manner. Interestingly we did not observe mitochondrial involvement in the process of cell death. Measures on semipurified proteasome from RS4;11 and SEM cell extracts demonstrated that chymotrypsin-, trypsin- and caspase-like activity decreased in the presence of CP. Moreover, we found an accumulation of ubiquitinated proteins and a remarkable increase of ER stress markers: GRP78, CHOP, and the spliced form of XBP1. Accordingly, the protein synthesis inhibitor cycloheximide significantly protected cancer cells from CP-induced cell death, suggesting that protein synthesis machinery was involved. In well agreement with results obtained on stabilized cell lines, CP induced ER-stress and apoptosis also in primary cells from B-acute lymphoblastic leukemia patients. Importantly, we showed that the combination of CP with some chemotherapeutic drugs displayed a good synergy that strongly affected the survival of both RS4;11 and SEM cells.
一种膦铜（I）配合物[Cu(thp)4][PF6]（CP）最近被鉴定为一种高效的体外抗肿瘤剂。在本研究中，我们评估了CP在白血病细胞系中的抗增殖活性，发现其具有显著疗效，尤其是对SEM和RS4;11细胞。免疫印迹分析显示半胱天冬酶-12、半胱天冬酶-9以及两种效应半胱天冬酶-3和-7被激活，这表明细胞死亡是以半胱天冬酶依赖的方式发生的。有趣的是，我们没有观察到线粒体参与细胞死亡过程。对来自RS4;11和SEM细胞提取物的半纯化蛋白酶体的检测表明，在CP存在的情况下，胰凝乳蛋白酶、胰蛋白酶和半胱天冬酶样活性降低。此外，我们发现泛素化蛋白积累以及内质网应激标志物：GRP78、CHOP和XBP1的剪接形式显著增加。因此，蛋白质合成抑制剂放线菌酮显著保护癌细胞免受CP诱导的细胞死亡，这表明蛋白质合成机制参与其中。与在稳定细胞系上获得的结果高度一致，CP在B-急性淋巴细胞白血病患者的原代细胞中也诱导内质网应激和凋亡。重要的是，我们表明CP与一些化疗药物的联合显示出良好的协同作用，强烈影响RS4;11和SEM细胞的存活。
