Panchuk Rostyslav R, Lehka Lilya V, Terenzi Alessio, Matselyukh Bohdan P, Rohr Jürgen, Jha Amit K, Downey Theresa, Kril Iryna J, Herbacek Irene, van Schoonhoven Sushilla, Heffeter Petra, Stoika Rostyslav S, Berger Walter
Institute of Cell Biology NAS of Ukraine, Lviv, Ukraine.
Institute of Inorganic Chemistry, University of Vienna, Vienna, Austria.
Free Radic Biol Med. 2017 May;106:134-147. doi: 10.1016/j.freeradbiomed.2017.02.024. Epub 2017 Feb 9.
Landomycin E (LE) is an angucycline antibiotic produced by Streptomyces globisporus. Previously, we have shown a broad anticancer activity of LE which is, in contrast to the structurally related and clinically used anthracycline doxorubicin (Dx), only mildly affected by multidrug resistance-mediated drug efflux. In the present study, cellular and molecular mechanisms underlying the anticancer activity of landomycin E towards Jurkat T-cell leukemia cells were dissected focusing on the involvement of radical oxygen species (ROS). LE-induced apoptosis distinctly differed in several aspects from the one induced by Dx. Rapid generation of both extracellular and cell-derived hydrogen peroxide already at one hour drug exposure was observed in case of LE but not found before 24h for Dx. In contrast, Dx but not LE induced production of superoxide radicals. Mitochondrial damage, as revealed by JC-1 staining, was weakly enhanced already at 3h LE treatment and increased significantly with time. Accordingly, activation of the intrinsic apoptosis pathway initiator caspase-9 was not detectable before 12h exposure. In contrast, cleavage of the down-stream caspase substrate PARP-1 was clearly induced already at the three hour time point. Out of all caspases tested, only activation of effector caspase-7 was induced at this early time points paralleling the LE-induced oxidative burst. Accordingly, this massive cleavage of caspase-7 at early time points was inhibitable by the radical scavenger N-acetylcysteine (NAC). Additionally, only simultaneous inhibition of multiple caspases reduced LE-induced apoptosis. Specific scavengers of both HO and OH effectively decreased LE-induced ROS production, but only partially inhibited LE-induced apoptosis. In contrast, NAC efficiently blocked both parameters. Summarizing, rapid HO generation and a complex caspase activation pattern contribute to the antileukemic effects of LE. As superoxide generation is considered as the main cardiotoxic mechanism of Dx, LE might represent a better tolerable drug candidate for further (pre)clinical development.
兰多霉素E（LE）是由球形链霉菌产生的一种安莎霉素类抗生素。此前，我们已经证明LE具有广泛的抗癌活性，与结构相关且临床使用的蒽环类药物阿霉素（Dx）相比，它仅受到多药耐药介导的药物外排的轻微影响。在本研究中，我们剖析了兰多霉素E对Jurkat T细胞白血病细胞抗癌活性的细胞和分子机制，重点关注活性氧（ROS）的参与情况。LE诱导的凋亡在几个方面与Dx诱导的凋亡明显不同。在LE处理1小时后就观察到细胞外和细胞来源的过氧化氢迅速生成，而Dx在24小时之前未观察到这种情况。相反，Dx能诱导超氧阴离子自由基的产生，而LE则不能。JC-1染色显示，在LE处理3小时后线粒体损伤就略有增强，并随时间显著增加。因此，在暴露12小时之前未检测到内源性凋亡途径起始半胱天冬酶-9的激活。相反，在3小时时间点就明显诱导了下游半胱天冬酶底物PARP-1的切割。在所有测试的半胱天冬酶中，只有效应半胱天冬酶-7在这个早期时间点被激活，这与LE诱导的氧化爆发同时发生。因此，在早期时间点半胱天冬酶-7的大量切割可被自由基清除剂N-乙酰半胱氨酸（NAC）抑制。此外，只有同时抑制多种半胱天冬酶才能减少LE诱导的凋亡。HO和OH的特异性清除剂有效地降低了LE诱导的ROS产生，但仅部分抑制了LE诱导的凋亡。相比之下，NAC有效地阻断了这两个参数。总之，快速的HO生成和复杂的半胱天冬酶激活模式有助于LE的抗白血病作用。由于超氧阴离子的产生被认为是Dx的主要心脏毒性机制，LE可能是一种耐受性更好的药物候选物，可用于进一步的（临床前）临床开发。
