Department of Pharmaceutical Biology, Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg University-Mainz, Staudinger Weg 5, 55128, Mainz, Germany.
Department of Chemistry, University of Isfahan, Isfahan, 81746-73441, Iran.
Eur J Pharmacol. 2023 Oct 5;956:175980. doi: 10.1016/j.ejphar.2023.175980. Epub 2023 Aug 9.
The use of cisplatin and its derivatives in cancer treatment triggered the interest in metal-containing complexes as potential novel anticancer agents. Palladium (II)-based complexes have been synthesized in recent years with promising antitumor activity. Previously, we described the synthesis and cytotoxicity of palladium (II) complexes containing halogen-substituted Schiff bases and 2-picolylamine. Here, we selected two palladium (II) complexes with double chlorine-substitution or double iodine-substitution that displayed the best cytotoxicity in drug-sensitive CCRF-CEM and multidrug-resistant CEM/ADR5000 leukemia cells for further biological investigation. Surprisingly, these compounds did not significantly induce apoptotic cell death. This study aims to reveal the major mode of cell death of these two palladium (II) complexes. We performed annexin V-FITC/PI staining and flow cytometric mitochondrial membrane potential measurement followed by western blotting, immunofluorescence microscopy, and alkaline single cell electrophoresis (comet assay). J4 and J6 still induced neither apoptosis nor necrosis in both leukemia cell lines. They also insufficiently induced autophagy as evidenced by Beclin and p62 detection in western blotting. Interestingly, J4 and J6 induced a novel mode of cell death (parthanatos) as mainly demonstrated in CCRF-CEM cells by hyper-activation of poly(ADP-ribose) polymerase 1 (PARP) and poly(ADP-ribose) (PAR) using western blotting, flow cytometric measurement of mitochondrial membrane potential collapse, nuclear translocation of apoptosis-inducing factor (AIF) by immunofluorescence microscopy, and DNA damage by alkaline single cell electrophoresis (comet assay). AIF translocation was also observed in CEM/ADR5000 cells. Thus, parthanatos was the predominant mode of cell death induced by J4 and J6, which explains the high cytotoxicity in CCRF-CEM and CEM/ADR5000 cells. J4 and J6 may be interesting drug candidates and deserve further investigations to overcome resistance of tumors against apoptosis. This study will promote the design of further novel palladium (II)-based complexes as chemotherapeutic agents.
顺铂及其衍生物在癌症治疗中的应用激发了人们对含金属配合物作为潜在新型抗癌药物的兴趣。近年来，已经合成了钯（II）基配合物，具有有前途的抗肿瘤活性。此前，我们描述了含有卤素取代席夫碱和 2-吡啶甲胺的钯（II）配合物的合成和细胞毒性。在这里，我们选择了两种在敏感的 CCRF-CEM 和多药耐药的 CEM/ADR5000 白血病细胞中显示出最佳细胞毒性的具有双重氯取代或双重碘取代的钯（II）配合物进行进一步的生物学研究。令人惊讶的是，这些化合物并没有显著诱导细胞凋亡。本研究旨在揭示这两种钯（II）配合物的主要细胞死亡方式。我们进行了 Annexin V-FITC/PI 染色和流式细胞术线粒体膜电位测量，随后进行了 Western blot、免疫荧光显微镜和碱性单细胞电泳（彗星试验）。J4 和 J6 仍然没有在两种白血病细胞系中诱导凋亡或坏死。Western blot 检测到 Beclin 和 p62 表明它们也不足以诱导自噬。有趣的是，J4 和 J6 诱导了一种新型的细胞死亡方式（parthanatos），主要在 CCRF-CEM 细胞中表现为聚（ADP-核糖）聚合酶 1（PARP）和聚（ADP-核糖）（PAR）的超激活，通过 Western blot、流式细胞术测量线粒体膜电位崩溃、凋亡诱导因子（AIF）的核转位通过免疫荧光显微镜和碱性单细胞电泳（彗星试验）检测到 DNA 损伤。AIF 转位也在 CEM/ADR5000 细胞中观察到。因此，parthanatos 是 J4 和 J6 诱导的主要细胞死亡方式，这解释了它们在 CCRF-CEM 和 CEM/ADR5000 细胞中的高细胞毒性。J4 和 J6 可能是有趣的药物候选物，值得进一步研究以克服肿瘤对凋亡的抵抗。本研究将促进进一步设计新型钯（II）基配合物作为化疗药物。
