Department of Medical Biology and Genetics, Faculty of Medicine in Hradec Kralove, Charles University, Zborovska 2089, 500 03 Hradec Kralove, Czech Republic.
Int J Mol Sci. 2022 Jul 27;23(15):8312. doi: 10.3390/ijms23158312.
Zinc levels in serum and/or tissue are reported to be altered in melanoma with unknown effects on melanoma development and biology. The purpose of this study was to examine the effects of acute chelation of free intracellular zinc pools in melanoma cell lines Bowes and A375, as well as selected melanoma tissue explants with high or low intracellular free zinc. Zinc chelating agent TPEN at the concentration of 25 µM was employed during 48 h, which significantly reduced intracellular free zinc while decreasing melanoma cell proliferation, inducing G1/S arrest and cell damage leading to mitochondrial, caspase-dependent apoptosis. Chelation of free zinc was also associated with increased generation of superoxide in cell lines but not marked lysosomal membrane damage. Conversely, melanoma explant cultures mostly displayed time-dependent loss of lysosomal membrane integrity in the presence of slowly growing superoxide levels. Loss of free zinc-dependent p53 activity was similarly disparate in individual melanoma models. Surviving melanoma cells were arrested in the cell cycle, and varying proportions of them exhibited features characteristic of premature senescence, which increased in time despite zinc reloading. The present results show that melanoma cells with varying free zinc levels respond to its acute loss in a number of individual ways, reflecting activated mechanisms including oxidative stress, lysosomal damage, and p53 activity leading to heterogenous outcomes including cell death, transient, and/or permanent cell cycle arrest and premature senescence.
血清和/或组织中的锌水平据报道在黑色素瘤中发生改变，但对黑色素瘤的发展和生物学影响尚不清楚。本研究的目的是研究急性螯合黑色素瘤细胞系 Bowes 和 A375 以及具有高或低细胞内游离锌的选定黑色素瘤组织外植体中的游离细胞内锌池对黑色素瘤的影响。在 48 小时内使用浓度为 25 µM 的锌螯合剂 TPEN，显著降低细胞内游离锌，同时抑制黑色素瘤细胞增殖，诱导 G1/S 期阻滞和细胞损伤，导致线粒体依赖性细胞凋亡。游离锌的螯合还与细胞系中超氧自由基的生成增加有关，但没有明显的溶酶体膜损伤。相反，黑色素瘤外植体培养物在缓慢生长的超氧自由基水平存在下，主要表现为溶酶体膜完整性的时间依赖性丧失。个体黑色素瘤模型中，游离锌依赖性 p53 活性的丧失也存在明显差异。存活的黑色素瘤细胞被阻滞在细胞周期中，其中不同比例的细胞表现出衰老的特征，尽管锌再加载，但随着时间的推移，这些特征会增加。本研究结果表明，具有不同游离锌水平的黑色素瘤细胞以多种个体方式对其急性缺失做出反应，反映了激活的机制，包括氧化应激、溶酶体损伤和 p53 活性，导致包括细胞死亡、短暂和/或永久性细胞周期阻滞和过早衰老在内的异质结果。
