Intermittent PTH1-34 Causes DNA and Chromosome Breaks in Osteoblastic and Nonosteoblastic Cells
Intermittent PTH1-34 Causes DNA and Chromosome Breaks in Osteoblastic and Nonosteoblastic Cells
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DOI：
10.1007/s00223-010-9396-6
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发表时间：
2010-11-01
影响因子：
4.2
通讯作者：
de Moura Castro, Charlles Heldan
中科院分区：
文献类型：
--
作者：
Alves de Oliveira, Elisangela Claudia;Szejnfeld, Vera Lucia;de Moura Castro, Charlles Heldan
毒理学研究表明，间歇性PTH 1 -34治疗与Fischer 344大鼠骨肉瘤发病率增加有关。彗星和微核（MN）试验，标准方法，以评估药物的遗传毒性潜力，分别用于检测DNA和染色体断裂后，PTH 1 -34处理。将MC 3 T3细胞、原代成骨细胞颅骨细胞和人成骨细胞用PTH 1 -34（50和100 nM）处理6小时/天，持续21天，以模拟间歇给药。在6 h和7、14和21天进行遗传毒性试验。还测试了从每天皮下注射PTH 1 -34（20和40 μ g/kg）处理10周的小鼠的骨髓中提取的成骨细胞以及Hep-2、HeLa和Hep-G2细胞。我们观察到与对照组相比，用PTH 1 -34处理的人和鼠成骨细胞中DNA损伤和MN患病率显著增加（P < 0.01）。在体外观察到并在体内证实的效应具有时间和剂量依赖性。对于非成骨细胞Hep-2和HeLa细胞，我们观察到DNA损伤和MN患病率仅在治疗过程的后期，即治疗21天后增加（P < 0.01）。在Hep-G2细胞中，间歇性PTH 1 -34不诱导DNA损伤或染色体断裂。我们的研究结果表明，间歇性甲状旁腺激素增加成骨细胞的DNA和染色体断裂。这种遗传毒性作用在非成骨细胞中减弱，并且在体外测试的具有解毒特性的细胞（HepG 2细胞）中丧失诱导DNA损伤的能力。
Toxicological studies have demonstrated that intermittent PTH1-34 treatment is associated with an increased incidence of osteosarcoma in Fischer 344 rats. Comet and micronucleus (MN) tests, standard methods to evaluate genotoxic potential of drugs, were used to detect DNA and chromosome breaks, respectively, after PTH1-34 treatment. MC3T3 cells, primary osteoblast calvarial cells, and human osteoblasts were treated with PTH1-34 (50 and 100 nM) for 6 h/day for 21 days to mimic intermittent administration. Genotoxic assays were performed at 6 h and 7, 14, and 21 days. Osteoblasts extracted from bone marrow of mice treated with daily subcutaneous PTH1-34 injections (20 and 40 mu g/kg) for 10 weeks as well as Hep-2, HeLa, and Hep-G2 cells were also tested. We observed a significant increase in DNA lesions and MN prevalence in human and murine osteoblasts treated with PTH1-34 compared to controls (P < 0.01). The effect observed in vitro and confirmed in vivo was time- and dose-dependent. For nonosteoblastic Hep-2 and HeLa cells we observed increased DNA damage and MN prevalence only later in the course of the protocol, after 21 days of treatment (P < 0.01). In Hep-G2 cells intermittent PTH1-34 did not induce DNA damage or chromosome breaks. Our results demonstrated that intermittent PTH increases DNA and chromosome breaks in osteoblasts. This genotoxic effect is attenuated in nonosteoblastic cells, and the ability to induce DNA damage is lost in cells with detoxification properties (HepG2 cells) tested in vitro.