Podtcheko Alexei, Namba Hiroyuki, Saenko Vladimir, Ohtsuru Akira, Starenki Dmitriy, Meirmanov Serik, Polona Iryna, Rogounovitch Tatiana, Yamashita Shunichi
Department of Molecular Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
Thyroid. 2005 Apr;15(4):306-13. doi: 10.1089/thy.2005.15.306.
Premature senescence may play an important role as an acute, drug-, or ionizing radiation (IR)-inducible growth arrest program along with interphase apoptosis and mitotic catastrophe. The aim of the study was to evaluate whether IR can induce senescence-like phenotype (SLP) associated with terminal growth arrest in the thyroid cells, and if so, to evaluate impact of terminal growth arrest associated with SLP in intrinsic radiosensitivity of various thyroid carcinomas. The induction of SLP in thyroid cells were identified by: (1) senescence associated beta-galactosidase (SA-beta-Gal) staining method, (2) dual-flow cytometric analysis of cell proliferation and side light scatter using vital staining with PKH-2 fluorescent dye, (3) double labeling for 5-bromodeoxyuridine and SA- beta-Gal, (4) Staining for SA-beta-Gal with consequent antithyroglobulin immunohistochemistry. IR induced SLP associated with terminal growth arrest in four thyroid cancer cells lines and in primary thyrocytes in time- and dose-dependent manner. Analysis of relationship between induction of SLP and radiosensitivity revealed a trend in which more radioresistant cell lines strongly tended to show lower specific SLP yields (r = -0.93, p = 0.068). We find out that SA-beta-Gal staining is detectable in irradiated ARO xenotransplants, but not in control tumors. We, therefore, conclude that induction of SLP with terminal growth arrest contribute to the elimination of clonogenic populations after IR.
早衰可能作为一种急性、药物或电离辐射（IR）诱导的生长停滞程序，与间期凋亡和有丝分裂灾难一起发挥重要作用。本研究的目的是评估IR是否能诱导甲状腺细胞中与终末生长停滞相关的衰老样表型（SLP），如果是，评估与SLP相关的终末生长停滞对各种甲状腺癌内在放射敏感性的影响。甲状腺细胞中SLP的诱导通过以下方法鉴定：（1）衰老相关β-半乳糖苷酶（SA-β-Gal）染色法；（2）使用PKH-2荧光染料进行活细胞染色，对细胞增殖和侧向光散射进行双流式细胞术分析；（3）5-溴脱氧尿苷和SA-β-Gal双重标记；（4）SA-β-Gal染色后进行抗甲状腺球蛋白免疫组织化学染色。IR以时间和剂量依赖性方式在四种甲状腺癌细胞系和原代甲状腺细胞中诱导与终末生长停滞相关的SLP。对SLP诱导与放射敏感性之间关系的分析显示出一种趋势，即放射抗性更强的细胞系强烈倾向于显示出更低的特定SLP产量（r = -0.93，p = 0.068）。我们发现SA-β-Gal染色在照射后的ARO异种移植瘤中可检测到，但在对照肿瘤中未检测到。因此，我们得出结论，诱导具有终末生长停滞的SLP有助于在IR后消除克隆性群体。
