RNA干扰securin对胶质瘤凋亡、替莫唑胺耐药性的影响及机制研究

Glioma is the most common tumor in the central nervous system, operation combining with chemotherapy of Temozolomide was standard treatment.However, due to the activity of invasion and presence of chemotherapy drugs intrinsic and acquired drug resistance phenomenon,it has great influence on the effect of chemotherapy. At present the tageting gene and mechanism were not understand about the treatment on human glioma. Securin is a novel oncogene which is expressed at higher level in most of the tumor tissues. Securin could inhibite chromosome separation in the mitotic phase, regulate cell cycle and involved in the formation of tumors.Our study showed that higher level of securin was expressed in the glioma tissues compared to normal tissues.The intensity of securin protein in the tissues showed positive correlation with the glioma pathogenic grade,suggesting it has close correlation with tumor generation, development and prognosis. In order to further understand the role of securin on opoptosis and related signaling pathway in glioma, the present study established models of securin downregulation in glioma cell U373 using securin siRNA. Using these models,the effect of securin on glioma invasion, and chemotherapy sensibility to TMZ were investigated,and test whether this effect was carried out via PI3K/Akt pathway. RNAi targeting securin gene might offer a new target for the treatment of glioma.

胶质瘤是中枢神经系统最常见的恶性疾病，手术和替莫唑胺化疗是标准治疗方式。但是胶质瘤的高侵袭性及对替莫唑胺药物耐药性增加是导致胶质瘤细胞生长失控和化疗效果差的主要原因，但是介导上述作用的靶基因及其作用机制尚不清楚。分离酶抑制蛋白（securin）是一种原癌基因，可抑制染色体有丝分裂，诱导细胞多倍体性、调控细胞周期，参与肿瘤的形成。我们前期研究发现securin在胶质瘤中表达增强，并与肿瘤的TNM分期呈正相关，提示securin与胶质瘤进展密切相关。为进一步阐述该基因对胶质瘤细胞凋亡及相关信号通路的影响，介导对替莫唑胺耐药的机制，我们运用RNA干扰技术构建securin干扰质粒，将其转染至胶质瘤U373细胞检测对替莫唑胺敏感性、细胞凋亡相关PI3K/AKT通路的影响，探讨沉默securin是否可以通过抑制PI3K/AKT信号通路活化促进凋亡、提高化疗敏感性，为胶质瘤的治疗寻找新靶点及治疗手段。

胶质瘤是中枢神经系统最常见的恶性疾病，手术和替莫唑胺化疗是标准治疗方式。但是胶质瘤的高侵袭性及对替莫唑胺药物耐药性增加是导致胶质瘤细胞生长失控和化疗效果差的主要原因，但是介导上述作用的靶基因及其作用机制尚不清楚。分离酶抑制蛋白（securin）是一种原癌基因，可抑制染色体有丝分裂，诱导细胞多倍体性、调控细胞周期，参与肿瘤的形成。我们研究发现securin在胶质瘤中表达增强，并与肿瘤恶性程度呈正相关，提示securin与胶质瘤进展密切相关。为进一步阐述该基因对胶质瘤细胞凋亡及相关信号通路的影响，介导对替莫唑胺耐药的机制，我们运用RNA干扰技术合成securin siRNA及构建securin过表达质粒将其转染至胶质瘤细胞U87和U373中,通过MTT实验证实securin促进胶质瘤细胞增殖，沉默securin后可以抑制胶质瘤细胞增殖、抑制胶质瘤的血管生成及侵袭能力。通过RT-PCR验证下调 securin的表达,可以明显抑制 p-PI3K 和 p-Akt 表达水平。进一步检测胶质瘤细胞对替莫唑胺敏感性、细胞凋亡相关PI3K/AKT通路的影响，探讨沉默securin是否可以通过抑制PI3K/AKT信号通路活化促进凋亡、提高化疗敏感性。结果发现securin siRNA与替莫唑胺联合可进一步抑制胶质瘤细胞增殖、促进凋亡、增加胶质瘤细胞对化疗药物的敏感性,并且上述作用是通过抑制PI3K/AKT信号通路实现的。针对securin的基因治疗可能为胶质瘤的治疗提供新的策略。