P53凋亡刺激蛋白（ASPP）是一类与p53相互作用而影响其正常抑癌功能的基因家族。其中iASPP是唯一且进化最保守的p53功能抑制因子，在调控多种肿瘤细胞增殖、侵袭和放化疗耐受中起重要作用。p53功能异常是影响脊索瘤发生的关键因素之一，但对p53抑制因子iASPP在脊索瘤发生发展中的作用尚无研究报道。我们前期研究对21例脊索瘤组织检测发现，所有瘤组织iASPP都呈过表达，显著高于对照组织；而且，复发瘤组织中的iASPP表达水平也明显高于原发瘤组织。这些结果初步提示iASPP可能影响脊索瘤发生发展。因此，本研究拟继续扩大样本量进行检测，明确iASPP在脊索瘤诊断和预后评估中的临床指导意义；基于iASPP与p53的相互作用，着重探索脊索瘤发生中涉及的潜在上、下游信号调控机制如Hedgehog等，为后续脊索瘤分子靶向治疗研究提供重要理论依据。

P53 apoptosis stimulating protein (ASPP) is a gene family that can interact with p53 and interrupt its normal function as tumor suppressor. Wherein, iASPP is the only and evolutionarily conserved inhibitor of p53, which plays an important role in the regulation of cell proliferation, invasion and radio-chemotherapy tolerance in a variety of tumors. Dysfunction of p53 is one of the critical reasons that affects the carcinogenesis of chordoma, while the potential role of iASPP, the p53 inhibitor, in the carcinogenesis and development of chordoma has yet been reported. In our previous study, we have detected the expression of iASPP in 21 cases of chordoma, which showed that iASPP was over-expressed in all tumor tissues and significantly higher than the control tissues. In addition, the expression levels of iASPP in recurrent tumors were also remarkably higher than original tumors. These results preliminary indicated that iASPP might involve in regulating the carcinogenesis and development of chordoma. Therefore, in present study, we will continuously detect the expressions of iASPP in expanded samples to verify the clinical guiding significance of iASPP in the diagnosis and prognosis evaluation of chordoma. Then, we also focus on the exploration of potential upstream and downstream regulatory mechanisms (such as Hedgehog signaling pathways) in the carcinogenesis of chordoma that based on the interaction between iASPP and p53. These studies can provide an important theoretical basis for further studies on the molecular targeted therapy of chordoma.

既往研究发现P53凋亡刺激蛋白（iASPP）在多种肿瘤类型中高表达，与肿瘤发生发展密切相关，可参与调节肿瘤细胞增殖、凋亡、侵袭和化疗耐受等过程，但iASPP在脊索瘤中的功能和机制尚无研究报道。本项目研究通过检测iASPP在脊索瘤组织和细胞中的表达，对其表达和患者临床相关指标行相关性分析，并构建iASPP过表达/沉默细胞稳转株检测iASPP表达变化对多种细胞生物学行为（如增殖、侵袭、对顺铂药物敏感性）的影响，初步明确iASPP异常表达在脊索瘤发生发展中的作用；检测脊索瘤中miRNA-124表达在转录后水平对iASPP表达的调控作用，应用内源性和外源性免疫共沉淀技术明确iASPP与p53的相互作用，同时检测miRNA-124引起iASPP表达变化对p53下游参与细胞凋亡相关基因表达的影响。研究结果显示脊索瘤组织和细胞中iASPP存在过表达，与肿瘤局部侵袭、复发和患者不良预后显著相关；iASPP过表达能够显著增强细胞增殖和侵袭性，降低对顺铂的敏感性，而 iASPP沉默后前述现象呈反向变化。另外，脊索瘤组织和细胞中miRNA-124丰度低，与iASPP水平呈负向相关性，能够负向调节iASPP的表达；同时，脊索瘤细胞中iASPP与p53存在相互作用，miRNA-124对iASPP的负向调控作用能通过p53依赖性方式影响细胞凋亡相关基因（如bcl-2和bax）和凋亡效应因子caspase-3的表达。这些结果表明iASPP在脊索瘤发生发展中具有重要作用，可能成为预测脊索瘤复发和不良预后的重要标志以及脊索瘤药物治疗靶点；另外，研究结果初步阐明脊索瘤中miRNA-124下调引起iASPP高表达，并通过p53依赖性方式抑制促凋亡基因，可能是脊索瘤化疗耐受的原因之一。这些结果为后续探索脊索瘤中iASPP参与调控的潜在信号转导机制和其在体作用研究提供了重要的理论铺垫。