Inhibition of SOX2 induces cell apoptosis and G1/S arrest in Ewing's sarcoma through the PI3K/Akt pathway.
Inhibition of SOX2 induces cell apoptosis and G1/S arrest in Ewing's sarcoma through the PI3K/Akt pathway.
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DOI：
10.1186/s13046-016-0321-3
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发表时间：
2016-03-11
期刊：
影响因子：
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通讯作者：
Guo W
中科院分区：
文献类型：
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作者：
Ren C;Ren T;Yang K;Wang S;Bao X;Zhang F;Guo W
尤文氏肉瘤是一种侵袭性骨和软组织肿瘤，在儿童和青少年中发病率很高。由于其恶性程度高、预后差，因此有必要寻找新的生物标志物进行干预治疗，以改善预后。EWS/FLI1融合基因是大多数尤文肉瘤的特征。性别决定区Y-box 2（SOX 2）是EWS/FLI1的主要靶点。它已被确定为一种致癌基因，并与几种类型的癌症中的细胞凋亡抗性有关。然而，其在尤文氏肉瘤中的作用和调节机制在很大程度上是未知的。我们系统地研究了SOX 2在尤文肉瘤细胞系、人体组织样本和异种移植模型中的作用。免疫组化和WB法检测尤文肉瘤中SOX 2的表达。使用siRNA敲低A673和RD-ES细胞系中的EWS/FLI1和SOX 2，通过qRT-PCR和WB测试效率。流式细胞术和TUNEL法检测SOX 2对细胞周期和凋亡的影响。用质粒进行Akt过表达。WB分析相应因子的蛋白表达。在异种移植模型中通过针对SOX 2的siRNA进行SOX 2的体内抑制，并通过IHC和WB检测异种移植肿瘤中体外证实的调节剂的蛋白表达。结果证实SOX 2在尤文肉瘤中高表达，并且是EWS/FLI1的靶点。SOX 2通过调节p21、p27和cyclin-E促进尤文肉瘤细胞的G1/S期转变，并通过内源性凋亡途径（caspase-9、Bad、Bcl-2和XIAP）和外源性凋亡途径（Fas和caspase-8）介导caspase-3、PARP抑制尤文肉瘤细胞凋亡，从而促进尤文肉瘤细胞的存活和增殖。另外，SOX 2通过激活PI3K/Akt信号通路调节细胞周期进程和凋亡。其作用机制在体内外均得到证实。结果表明，SOX 2在体外和体内促进尤文肉瘤细胞增殖中发挥了核心作用，并阐述了其潜在机制。这些发现表明，SOX 2可能作为一个潜在的生物标志物，有针对性地干预尤文肉瘤。
Ewing’s sarcoma is an aggressive bone and soft tissue tumor with a high incidence in children and adolescents. Due to its high malignancy and poor prognosis, identification of novel biomarkers for intervention therapies is necessary to improve outcome. The EWS/FLI1 fusion gene is a characteristic of Ewing’s sarcoma in most cases. Sex determining region Y-box 2 (SOX2) is a primary target of EWS/FLI1. It has been identified as an oncogene and linked to apoptotic resistance in several types of cancer. However, its role and regulatory mechanisms in Ewing’s sarcoma are largely unknown. We systematically investigated the role of SOX2 in Ewing’s sarcoma cell lines, human tissue samples and xenograft models. The expression of SOX2 was detected in Ewing’s sarcoma samples by WB and IHC. siRNAs were used to knockdown EWS/FLI1 and SOX2 in A673 and RD-ES cell lines with the efficiencies tested by qRT-PCR and WB. The effect of SOX2 on cell cycle and apoptosis was determined by Flow cytometric and TUNEL assays. Akt overexpression was performed with plasmid. The protein expression of the corresponding factors was examined by WB analysis. Inhibition of SOX2 in vivo was performed by siRNA against SOX2 in xenograft models, and the protein expression of the regulators testified in vitro was examined in xenograft tumors by IHC and WB. The results confirmed that SOX2 was highly expressed in Ewing’s sarcoma and was the target of EWS/FLI1. SOX2 advanced Ewing’s sarcoma cell survival and proliferation by regulating p21, p27 and cyclin-E to facilitate G1/S phase transition and mediating caspase-3, PARP via both extrinsic (Fas and caspase-8) and intrinsic (caspase-9, Bad, Bcl-2 and XIAP) apoptotic pathways to restrain cell apoptotsis. Additionally, SOX2 regulated the cell-cycle progression and apoptosis via activation of the PI3K/Akt signaling pathway. The mechanisms were proved both in vitro and in vivo. The results demonstrate that SOX2 played a central role in promoting Ewing’s sarcoma cell proliferation in vitro and in vivo with the underlying mechanisms expounded. These findings suggest that SOX2 may serve as a potential biomarker for targeted intervention in Ewing’s sarcoma.