Onset of hepatocarcinogen-specific cell proliferation and cell cycle aberration during the early stage of repeated hepatocarcinogen administration in rats
Onset of hepatocarcinogen-specific cell proliferation and cell cycle aberration during the early stage of repeated hepatocarcinogen administration in rats
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DOI：
10.1002/jat.3163
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发表时间：
2016-02-01
影响因子：
3.3
通讯作者：
Shibutani，Makoto
中科院分区：
文献类型：
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作者：
Kimura，Masayuki;Abe，Hajime;Shibutani，Makoto
我们之前曾报道，对大鼠进行 28 天的致癌物治疗，诱发靶细胞增殖，激活 G1/S 检查点功能和细胞凋亡，并诱导异常泛素 D (Ubd) 表达，这表明大鼠的纺锤体检查点功能受到破坏。本研究旨在确定大鼠肝细胞发生致癌物特异性细胞周期畸变和增殖的起始时间。给动物口服致癌剂量的甲基丁子香酚或硫代乙酰胺，治疗3、7或28天。为了进行比较，一些动物接受了部分肝切除术或使用非致癌性肝毒药物（对乙酰氨基酚、α-萘基异硫氰酸酯或异丙嗪）进行治疗。第 28 天出现了致癌物特异性肝细胞动力学，细胞增殖、p21Cip1+ 细胞、磷酸化 Mdm2+ 细胞和裂解的 caspase 3+ 细胞的增加以及 DNA 损伤相关基因的上调很明显。肝癌物质还下调 Rbl2 并上调 Cdkn1a 和 Mdm2，并降低 Ki-67+ 增殖群体中共表达磷酸化组蛋白 H3 (p-组蛋白 H3) 的 Ubd+ 细胞和 p-组蛋白 H3+ 细胞比例。这些结果表明，由于纺锤体检查点功能被破坏，需要 28 天才能诱导肝癌特异性增殖细胞从 M 期提前退出，这一点可以通过停留在 M 期的 Ubd+ 细胞减少来证明。 Rbl2 下调和 Mdm2 上调反映的 G1/S 检查点功能的破坏（暗示视网膜母细胞瘤蛋白的隔离）是促进第 28 天致癌物诱导的细胞增殖的原因。DNA 损伤的积累可能与 Mdm2 激活促进 p53 降解有关，可能是异常 p21Cip1 激活的先决条件，而 p21Cip1 激活是细胞凋亡的原因。版权所有 © 2015 约翰·威利父子有限公司
We have previously reported that a 28‐day treatment of carcinogens evoking target cell proliferation activates G1/S checkpoint function and apoptosis, as well as induction of aberrant ubiquitin D (Ubd) expression, suggesting disruptive spindle checkpoint function, in rats. The present study aimed to determine the onset time of rat liver cells to undergo carcinogen‐specific cell cycle aberration and proliferation. Animals were treated orally with a hepatocarcinogenic dose of methyleugenol or thioacetamide for 3, 7 or 28 days. For comparison, some animals were subjected to partial hepatectomy or treated with noncarcinogenic hepatotoxicants (acetaminophen, α‐naphthyl isothiocyanate or promethazine). Carcinogen‐specific liver cell kinetics appeared at day 28 as evident by increases of cell proliferation, p21Cip1+cells, phosphorylated‐Mdm2+cells and cleaved caspase 3+cells, and upregulation of DNA damage‐related genes. Hepatocarcinogens also downregulatedRbl2and upregulatedCdkn1aandMdm2, and decreased Ubd+cells co‐expressing phosphorylated‐histone H3 (p‐Histone H3) and p‐Histone H3+cell ratio within the Ki‐67+proliferating population. These results suggest that it takes 28 days to induce hepatocarcinogen‐specific early withdrawal of proliferating cells from M phase due to disruptive spindle checkpoint function as evidenced by reduction of Ubd+cells staying at M phase. Disruption of G1/S checkpoint function reflected by downregulation ofRbl2as well as upregulation ofMdm2suggestive of sequestration of retinoblastoma protein is responsible for the facilitation of carcinogen‐induced cell proliferation at day 28. Accumulation of DNA damage probably in association with facilitation of p53 degradation by activation of Mdm2 may be a prerequisite for aberrant p21Cip1activation, which is responsible for apoptosis. Copyright © 2015 John Wiley & Sons, Ltd.