A novel anti-proliferative role of HMGA2 in induction of apoptosis through caspase 2 in primary human fibroblast cells.
A novel anti-proliferative role of HMGA2 in induction of apoptosis through caspase 2 in primary human fibroblast cells.
复制标题
HMGA2 在原代人成纤维细胞中通过 Caspase-2 诱导细胞凋亡中具有新的抗增殖作用。
DOI：
10.1042/bsr20140112
复制
发表时间：
2015-01-14
影响因子：
4
通讯作者：
Lu J
中科院分区：
文献类型：
--
作者：
Shi X;Tian B;Ma W;Zhang N;Qiao Y;Li X;Zhang Y;Huang B;Lu J
HMGA2（高迁移率组AT-hook）蛋白先前已被证明是一种癌蛋白，而HMGA2的异位表达被发现会诱导原代细胞的生长停滞。这一现象背后的确切机制仍有待阐明。在本研究中，我们确定HMGA2能够诱导WI38人原代细胞凋亡。我们发现，表达高水平HMGA2的WI38细胞被阻滞在G2/M期，并表现出凋亡核表型。同时，在HMGA2过表达8天后检测裂解型caspase 3（半胱氨酸天冬氨酸特异性蛋白酶3）。流式细胞术分析证实细胞凋亡比例显著增加。同时，还检测到其他主要凋亡标志物，包括p53、Bax和cleaved caspase 9上调，Bcl-2下调；以及线粒体中细胞色素c的释放。我们进一步证明shRNA介导的Apaf1（凋亡蛋白酶激活因子1）沉默部分挽救了hmga2诱导的细胞凋亡，并伴有cleaved caspase-3水平的降低和细胞死亡率的下降。我们的研究结果还发现，在hmga2诱导的细胞凋亡过程中，随着裂解型caspase 2的上调，γ - h2a在细胞核中积累，表明hmga2诱导的细胞凋亡依赖于DNA损伤途径。总体而言，本研究揭示了HMGA2在人原代细胞系诱导凋亡中的新功能，并为阐明HMGA2除了作为癌蛋白的功能外的机制作用提供了线索。
The HMGA2 (high-mobility group AT-hook) protein has previously been shown as an oncoprotein, whereas ectopic expression of HMGA2 is found to induce growth arrest in primary cells. The precise mechanisms underlying this phenomenon remain to be unravelled. In the present study, we determined that HMGA2 was able to induce apoptosis in WI38 primary human cells. We show that WI38 cells expressing high level of HMGA2 were arrested at G2/M phase and exhibited apoptotic nuclear phenotypes. Meanwhile, the cleaved caspase 3 (cysteine aspartic acid-specific protease 3) was detected 8 days after HMGA2 overexpression. Flow cytometric analysis confirmed that the ratio of cells undergoing apoptosis increased dramatically. Concurrently, other major apoptotic markers were also detected, including the up-regulation of p53, Bax and cleaved caspase 9, down-regulation of Bcl-2; as well as release of cytochrome c from the mitochondria. We further demonstrate that the shRNA (small-hairpin RNA)-mediated Apaf1 (apoptotic protease activating factor 1) silencing partially rescued the HMGA2-induced apoptosis, which was accompanied by the decrease of cleaved caspase-3 level and a decline of cell death ratio. Our results also reveal that γH2A was accumulated in nuclei during the HMGA2-induced apoptosis along with the up-regulation of cleaved caspase 2, suggesting that the HMGA2-induced apoptosis was dependent on the pathway of DNA damage. Overall, the present study unravelled a novel function of HMGA2 in induction of apoptosis in human primary cell lines, and provided clues for clarification of the mechanistic action of HMGA2 in addition to its function as an oncoprotein.