Frydrych Ivo, Mlejnek Petr
Faculty of Medicine and Dentistry, Department of Biology, Palacky University Olomouc, Hnevotinska 3, Olomouc 77515, Czech Republic.
J Cell Biochem. 2008 Dec 15;105(6):1501-6. doi: 10.1002/jcb.21971.
We recently demonstrated that TLCK and TPCK could act as potent but nonspecific inhibitors of mature caspases [Frydrych and Mlejnek [2008] J Cell Biochem 103:1646-1656]. The question whether TLCK and TPCK inhibit simultaneously caspase activation and/or processing remained, however, open. In this article, we demonstrated that TPCK even enhanced caspase-3 and caspase-7 processing although it substantially inhibited caspase-3 and caspase-7 enzymatic (DEVDase) activity in HL-60 cells exposed to various cell death inducing stimuli. Under the same conditions, TLCK had no effect or affected caspase-3 and caspase-7 processing marginally depending on cell treatment used. Importantly, TLCK substantially inhibited caspase-3 and caspase-7 enzymatic (DEVDase) activity irrespectively to the treatment used. Interestingly, treatment of cells with toxic concentrations of TPCK alone was accompanied by full caspase-3 and -7 processing even if it induced necrosis. In contrast, treatment of cells with concentrations of TLCK that caused necrosis was accompanied by only partial caspase-3 and caspase-7 processing. Our results clearly indicated that TPCK and TLCK did not inhibit caspase-3 and -7 enzymatic activity by prevention of their activation and/or processing.
我们最近证明，TLCK和TPCK可作为成熟半胱天冬酶的强效但非特异性抑制剂[Frydrych和Mlejnek [2008] J Cell Biochem 103:1646 - 1656]。然而，TLCK和TPCK是否同时抑制半胱天冬酶的激活和/或加工这一问题仍未解决。在本文中，我们证明，尽管TPCK在暴露于各种诱导细胞死亡刺激的HL - 60细胞中能显著抑制半胱天冬酶 - 3和半胱天冬酶 - 7的酶活性（DEVDase），但它甚至增强了半胱天冬酶 - 3和半胱天冬酶 - 7的加工过程。在相同条件下，TLCK根据所使用的细胞处理方式，要么没有影响，要么对半胱天冬酶 - 3和半胱天冬酶 - 7的加工过程影响很小。重要的是，无论使用何种处理方式，TLCK都能显著抑制半胱天冬酶 - 3和半胱天冬酶 - 7的酶活性（DEVDase）。有趣的是，单独用毒性浓度的TPCK处理细胞时，即使诱导了坏死，也伴随着半胱天冬酶 - 3和 - 7的完全加工。相反，用导致坏死的TLCK浓度处理细胞时，仅伴随着半胱天冬酶 - 3和半胱天冬酶 - 7的部分加工。我们的结果清楚地表明，TPCK和TLCK不是通过阻止半胱天冬酶 - 3和 - 7的激活和/或加工来抑制其酶活性的。
