Hara Hirokazu, Kobayashi Mari, Shiiba Moe, Kamiya Tetsuro, Adachi Tetsuo
Laboratory of Clinical Pharmaceutics, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu 501-1196, Japan.
J Clin Biochem Nutr. 2019 Jul;65(1):16-22. doi: 10.3164/jcbn.19-17. Epub 2019 Jun 11.
Plasma-activated medium (PAM) is a solution produced by exposing a liquid medium to non-thermal atmospheric pressure plasma (NTAPP). A number of reactive molecules, such as reactive oxygen species and reactive nitrogen species, are contained in PAM. Therefore, exposure to high doses of PAM results in cell death. We previously demonstrated that intracellular zinc (Zn) serves as an important mediator in PAM-induced cell death; however, the effects of sublethal treatment with PAM on cell functions are not fully understood. In the present study, we found that sublethal PAM treatment suppressed cell proliferation and induced senescence-like changes in lung adenocarcinoma A549 cells. Cell cycle analysis revealed that PAM induced cell cycle arrest at the G2/M phase. PAM increased the level of intracellular free Zn and the Zn chelator TPEN counteracted PAM-induced growth suppression, suggesting that Zn functions in PAM-induced growth suppression. In addition, sublethal treatment with PAM induced phosphorylation of ATM kinase, accumulation of p53 protein, and expression of p21 and GADD45A, which are known p53 target genes, in a Zn-dependent manner. These results suggest that the induction of growth arrest and cellular senescence by sublethal PAM treatment is mediated by Zn-dependent activation of the ATM/p53 pathway.
等离子体活化介质（PAM）是通过将液体介质暴露于非热大气压等离子体（NTAPP）而产生的一种溶液。PAM中含有许多活性分子，如活性氧和活性氮。因此，暴露于高剂量的PAM会导致细胞死亡。我们之前证明细胞内锌（Zn）是PAM诱导细胞死亡的重要介质；然而，PAM亚致死处理对细胞功能的影响尚未完全了解。在本研究中，我们发现PAM亚致死处理抑制了肺腺癌A549细胞的增殖并诱导了类似衰老的变化。细胞周期分析显示，PAM诱导细胞周期停滞在G2/M期。PAM增加了细胞内游离锌的水平，锌螯合剂TPEN抵消了PAM诱导的生长抑制，表明锌在PAM诱导的生长抑制中起作用。此外，PAM亚致死处理以锌依赖的方式诱导了ATM激酶的磷酸化、p53蛋白的积累以及已知的p53靶基因p21和GADD45A的表达。这些结果表明，PAM亚致死处理诱导的生长停滞和细胞衰老由ATM/p53途径的锌依赖性激活介导。
