Induction of cyclin D1 by submicromolar concentrations of arsenite in human epidermal keratinocytes
Induction of cyclin D1 by submicromolar concentrations of arsenite in human epidermal keratinocytes
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DOI：
10.1016/j.taap.2006.08.006
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发表时间：
2006-12-01
影响因子：
3.8
通讯作者：
Steinberg, Mark
中科院分区：
文献类型：
--
作者：
Hwang, Bor-Jang;Utti, Charles;Steinberg, Mark
砷是一种普遍存在的环境致癌物，但砷并不具有直接的致突变性，其致癌转化的机制还不清楚。为了深入了解砷的致癌特性，我们研究了亚微摩尔浓度的亚砷酸钠处理培养的人表皮角质形成细胞中细胞周期蛋白D1的表达。亚砷酸盐在200和800纳米之间的浓度超过3天的时间内带来了细胞生长速率的增加。在200和400 nM浓度下摄取活体染色剂、中性红、亚砷酸盐，在相同的处理期内导致细胞活力平行增加。细胞周期参数的流式细胞仪分析表明，生长刺激伴随着从G1到S/G2细胞周期隔室在亚砷酸盐处理的细胞中的伴随移位。细胞周期蛋白D1转录的实时PCR分析表明，有超过三倍的诱导细胞暴露于400纳米亚砷酸盐3天。Western印迹中细胞周期蛋白D水平的定量显示亚砷酸盐处理引起细胞周期蛋白D蛋白的时间依赖性诱导，表示在7天处理期后约2.0倍的诱导。电泳迁移率变动分析（EMSA）表明，亚砷酸盐也刺激结合的转录因子，AP 1和CREBP各自的结合基序在3天内。这支持了基于D型细胞周期蛋白持续上调导致GI/S检查点控制同时丧失的肿瘤发生机制。(c)2006年爱思唯尔公司All rights reserved.
Arsenic is a prevalent environmental carcinogen but arsenic is not directly mutagenic and the mechanism by which arsenite brings about oncogenic transformation is poorly understood. To gain insight into the oncogenic properties of arsenic, we studied the expression of cyclin D1 in cultured human epidermal keratinocytes treated with subt-nicromolar concentrations of sodium arsenite. Arsenite at concentrations between 200 and 800 nM over a 3-day period brought about an increase in cell growth rate. Uptake of the vital stain, neutral red, arsenite at 200 and 400 nM concentrations brought about a parallel increase in cell viability over the same treatment period. Analysis of cell cycle parameters by flow cytometry showed that the growth stimulation was accompanied by a concomitant shift from the G1 into the S/G2 cell cycle compartment in the arsenite-treated cells. Real-time PCR analysis of cyclin D1 transcription showed that there was an induction of more than three-fold in cells exposed to 400 nM arsenite for 3 days. Quantitation of cyclin D levels in Western blots showed that arsenite treatment caused a time-dependent induction of cyclin D proteins representing an induction of about 2.0-fold after a 7 day treatment period. Electrophoretic mobility shift assays (EMSA) showed that arsenite also stimulated binding of the transcription factors, AP1 and CREBP to their respective binding motifs within 3 days. This supports a mechanism of oncogenesis based on persistent upregulation of D type cyclins leading to a concomitant loss of GI/S checkpoint control. (c) 2006 Elsevier Inc. All rights reserved.