Delta 40 p 53 suppresses tumor cell proliferation and induces cellular senescence in hepatocellular carcinoma cells
Delta 40 p 53 suppresses tumor cell proliferation and induces cellular senescence in hepatocellular carcinoma cells
复制标题
Delta 40 p 53 抑制肿瘤细胞增殖并诱导肝细胞癌细胞衰老
DOI：
--
复制
发表时间：
2016
期刊：
影响因子：
--
通讯作者：
M. Yoneda
中科院分区：
文献类型：
--
作者：
Akinobu Ota;Haruhisa Nakao;Yumi Sawada;S. Karnan;M. Wahiduzzaman;Tadahisa Inoue;Yuji Kobayashi;Takaya Yamamoto;Norimitsu Ishii;Tomohiko Ohashi;Y. Nakade;Ken Sato;K. Itoh;H. Konishi;Y. Hosokawa;M. Yoneda
某些基因的剪接异构体会影响哺乳动物的遗传多样性。抑癌基因TP53在肝细胞癌的发生调控中起重要作用。Δ40P53(Delta40P53)是一种天然存在的P53亚型，缺乏N末端反式激活结构域，但对Δ40P53在肝癌发生发展中的作用知之甚少。在这里，我们首先报道了Δ40P53在肝癌细胞系中的作用。在P53细胞克隆中，克隆形成活性和细胞存活率显著下降，而SA-β-Gal阳性细胞百分率和p21表达显著增加。在Δ40P53基因敲除后，这些观察在P53细胞克隆中明显减弱。此外，外源性Δ40p53的表达显著抑制了TP53、TP53和TP53细胞的生长。值得注意的是，在表达热点突变Δ40p53/R175H的细胞中，Δ40p53诱导的肿瘤抑制活性显著减弱，该突变缺乏p53的转录活性。此外，Δ40P53的表达与全长P53蛋白的表达增加有关。这些发现加深了对肝癌分子发病机制的理解；Δ40p53在肝癌细胞中起着重要的肿瘤抑制作用。L S研究中心的L教授指出，肝细胞癌是世界上最常见的恶性肿瘤之一(Lozano等人，2012年)，它通常是在持续的微环境压力下发展起来的，包括化学物质暴露、肝炎病毒感染引起的慢性炎症、肝脏组织重塑和高脂肪饮食(Liu等人，2014年；西田和Goel，2011年)。作为一种启动肝癌发生的事件，抑癌基因P53的缺失已被证明与肝癌的发生密切相关。Trp53基因的缺失导致了大量小鼠的肝脏肿瘤的发展(Katz等人，2012年；Morris等人，2012年)，而在小鼠肝癌模型中恢复p53基因通过调节细胞衰老来限制肿瘤细胞的生长(薛等人，2007年)。因此，越来越多的证据表明TP53基因异常与肝细胞癌的发生发展有关。总体而言，某些基因的剪接异构体在生物多样性中发挥着重要作用。已知TP53基因可能编码至少12种P53亚型，其中四种不同的N端P53形式(全长、Δ40、Δ133和Δ160)与三个不同的CT端结构域(α、β和伽马)结合(Marcel et al，2012)。全长(FL)-P53蛋白(也称为TAp53Alpha)是典型的P53蛋白，而Δ40p53Alpha(也称为P53/47)是一种P53亚型，缺乏与FL-P53的第一个反式激活域(TAD-I)相对应的39个N端氨基酸，是从P53mRNA第252-254位核苷酸的第二个8月通过第二个内部核糖体进入位点翻译而来的(Olivares-Illana和Fçhraeus等人，2010年；魏等人，2012年)。最近的研究表明，Δ40p53α对人和小鼠都有生物学效应。过度表达p44的转基因小鼠(Δ40p53pha的小鼠同源基因)显示出明显的衰老迹象和较短的寿命(Maier等人，2004年；钱和陈，2013年)。据报道，Δ40p53pha在人类肺癌和黑色素瘤细胞中发挥抗癌作用(Yen等人，2002年；Candeias等人，2006年；高桥等人，2014年)。相比之下，L S等人的Jo ur na L等人报道了Δ40p53α通过FL-p53抑制小鼠成纤维细胞的生长(Courtois等人，2002年)。因此，Δ40p53α的生物学功能可能因细胞类型的不同而不同。虽然越来越多的证据表明Δ40p53pha与衰老和/或肿瘤抑制有关，但对Δ40p53pha在肝癌发生发展中的作用知之甚少。在本研究中，我们首次报道了Δ40p53α(以下简称Δ40p53)在肝细胞癌发生发展中的抑瘤作用。我们还讨论了Δ40P53诱导肿瘤抑制和衰老的可能分子机制。L S教授L同志的研究材料与方法
Splicing isoforms of certain genes impact on genetic biodiversity in mammals. The tumor suppressor TP53 gene plays an important role in the regulation of tumorigenesis in hepatocellular carcinoma (HCC). Delta40p53 (Δ40p53) is a naturally occurring p53 isoform that lacks Nterminal transactivation domain, yet little is known about the role of Δ40p53 in the development of HCC. Here, we first report the role of Δ40p53 in HCC cell lines. In the p53 cell clones, clonogenic activity and cell survival dramatically decreased, while the percentage of SA-β-gal positive cells as well as p21 expression significantly increased. These observations were clearly attenuated in the p53 cell clones after Δ40p53 knockdown. In addition, exogenous Δ40p53 expression significantly suppressed cell growth in TP53, TP53, and TP53 HCC cells. Notably, Δ40p53-induced tumor suppressor activity was markedly attenuated in cells expressing the hot-spot mutant, Δ40p53/R175H, which lacks transcriptional activity of p53. Moreover, Δ40p53 expression was associated with increased full-length p53 protein expression. These findings enhance the understanding of the molecular pathogenesis of HCC; Δ40p53 acts as an important tumor suppressor in HCC cells. Jo ur na l o f C el l S ci en ce • A dv an ce a rt ic le INTRODUCTION Hepatocellular carcinoma (HCC), one of the most frequent malignancies worldwide (Lozano et al., 2012), commonly develops in response to continuous microenvironmental stresses, including chemical exposure, chronic inflammation from hepatitis viral infection, tissue remodeling in the liver, and a high fat diet (Liu et al., 2014; Nishida and Goel, 2011). As an initiating oncogenic event in HCC, the disruption of the p53 tumor suppressor gene has been shown to be closely associated with hepatocarcinogenesis. Deletion of the Trp53 gene resulted in the development of liver tumors in a significant number of mice (Katz et al., 2012; Morris et al., 2012), while restoring p53 in a murine liver carcinoma model limited tumor cell growth by mediating cellular senescence (Xue et al., 2007). Thus, accumulating evidence implicates TP53 gene dysfunction in the development of HCC. In general, splicing isoforms of certain genes play an important role in biodiversity. It has known that TP53 gene potentially encodes at least twelve p53 isoforms, in which four different N-terminal p53 forms (full length, Δ40, Δ133, and Δ160) are combined with three different Cterminal domains (alpha, beta, and gamma) (Marcel et al, 2012). Full-length (FL)-p53 protein (also called TAp53alpha) is the canonical p53 protein, while Δ40p53alpha (also known as p53/47), a p53 isoform that lacks the 39 N-terminal amino acids corresponding to the first transactivation domain (TAD-I) of FL-p53, is translated from an in-frame second AUG at nucleotides 252-254 of p53 mRNA through a second internal ribosome entry site (Olivares-Illana and Fåhraeus et al., 2010; Wei et al., 2012). Recent studies demonstrated the biological effects of Δ40p53alpha in both humans and mice. Transgenic mice overexpressing p44, the mouse homolog of Δ40p53alpha, showed obvious signs of aging and a shorter lifespan (Maier et al., 2004; Qian and Chen, 2013). It has been reported that Δ40p53alpha exerts anti-cancer properties in human lung cancer and melanoma cells (Yin et al., 2002; Candeias et al., 2006; Takahashi et al., 2014). In contrast, Jo ur na l o f C el l S ci en ce • A dv an ce a rt ic le Courtois et al reported that Δ40p53alpha counteracts growth suppression via FL-p53 in mouse fibroblasts (Courtois et al., 2002). Thus, the biological function of Δ40p53alpha potentially varies according to cell type. Although accumulating evidence has implicated Δ40p53alpha in aging and/or tumor suppression, little is known about the involvement of Δ40p53alpha in the development of HCC. In the present study, we are the first to report the tumor suppressor role of Δ40p53alpha (here after called Δ40p53) in the development of HCC. We also discuss a possible molecular mechanism underlying Δ40p53-induced tumor suppression and senescence. Jo ur na l o f C el l S ci en ce • A dv an ce a rt ic le MATERIALS AND METHODS
影响因子：
29.4
作者：
Katz, Sarah-Fee;Lechel, Andre;Rudolph, K. Lenhard
通讯作者：
Rudolph, K. Lenhard