Department of Medical Genetics, School of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
Arch Iran Med. 2010 Jan;13(1):26-33.
Arsenic trioxide and 1,25-(OH)2D3 (vitamin D3) are used for the treatment of lymphocytic leukemia. However, the effects of combined treatment of these drugs are controversial. In this study, the combined effects of these drugs on the induction of apoptosis in NB4 cells were investigated using the neutral comet assay.
NB4 cells were treated with various doses of arsenic trioxide (0.1 - 3 microM) and vitamin D3 (100 - 600 nM (alone or in combination. Twenty-four hours after treatment, neutral comet assay was performed and apoptotic cells were scored under a fluorescent microscope following staining with ethidium bromide.
Results show that all doses of arsenic trioxide used in this study induced apoptosis in NB4 cells. The frequency of induced apoptosis was dose dependent and significantly higher than the controls (P<0.05 - 0.01). In contrast, vitamin D3 at concentrations of 100 - 600 nM produced no significant effect on apoptosis induction compared to the controls. Treatment of NB4 cells with a combination of arsenic trioxide and vitamin D3 resulted in reduction of apoptosis induced by arsenic trioxide which was not dependent on the dose of vitamin D3 (P<0.05).
Results indicate that arsenic trioxide is a potent inducer of apoptosis in NB4 cells and vitamin D3 significantly decreased the sensitivity of cells to the induction of apoptosis by arsenic trioxide. These findings suggest that 1,25-(OH)2D3 might be involved in anti-apoptotic processes via reactive oxygen species scavenging or other mechanisms not yet known.
三氧化二砷和 1,25-(OH)2D3（维生素 D3）用于治疗淋巴细胞白血病。然而，这些药物联合治疗的效果存在争议。在这项研究中，使用中性彗星试验研究了这些药物联合治疗对 NB4 细胞凋亡诱导的影响。
用不同剂量的三氧化二砷（0.1-3 μM）和维生素 D3（100-600 nM（单独或联合处理 NB4 细胞。处理 24 小时后，进行中性彗星试验，并用溴化乙锭染色后在荧光显微镜下评分凋亡细胞。
结果表明，本研究中使用的所有剂量的三氧化二砷均诱导 NB4 细胞凋亡。诱导凋亡的频率呈剂量依赖性，明显高于对照组（P<0.05-0.01）。相比之下，维生素 D3 浓度为 100-600 nM 与对照组相比，对凋亡诱导没有显著影响。用三氧化二砷和维生素 D3 联合处理 NB4 细胞导致三氧化二砷诱导的凋亡减少，而与维生素 D3 的剂量无关（P<0.05）。
结果表明，三氧化二砷是 NB4 细胞凋亡的有效诱导剂，维生素 D3 显著降低了细胞对三氧化二砷诱导凋亡的敏感性。这些发现表明，1,25-(OH)2D3 可能通过活性氧物质清除或其他尚未知的机制参与抗凋亡过程。
