低频低强度超声与姜黄素联合作用逆转ABCG2介导的胶质瘤侧群细胞多药耐药性的机制研究

Malignant glioma is an important problem that puzzles doctors and patients by higher recurrency and lower survival rates caused by multidrug resistance after surgery. Based on the former work of national natural foundation on multidrug resistance proteins, the expression of ABCG2 was inhibited by low frequency and intensity ultrasound on glioma cells and played the role of stem cells. And based on the theory of glioma stem cells, side population (SP) cells provide a key point to solve the difficult problem. We take the multidrug resistance protein-ABCG2 as a target point based on the multidrug theory of SP cells when we found the new method to reverse multidrug resistance mediated by ABCG2 by the combination of curcumin and low frequency and low intensity ultrasound. In our previous study, the identification of glioma stem cells and SP cells were already finished. The optimum conditions of curcumin and low intensity ultrasound will be set. And characteristics of the stem cells, multidrug resistance and Akt signaling related factors will be examined by the combination or individually to make sure the molecular mechanisms and the influence of survival rate on tumor-bearing mice by the combination of regular chemotherapy and methods mentioned above. Finally, we observe the survival rates of tumor-bearing rats after combination of chemotherapy, curcumin and low frequency ultrasound. This will help to supply a new idea and methods to solve the problem of higher recurrency and prolong the survival period of patients tumor-bearings.

恶性胶质瘤术后耐药引发高复发率/低生存率是困扰医务人员的重大问题，本课题组前期结题国家自然基金项目多药耐药蛋白研究工作中，发现低频低强度超声对ABCG2在胶质瘤细胞中表达具抑制作用。表达ABCG2的胶质瘤侧群（Side population, SP）细胞具干细胞的特性，上述理论为解决胶质瘤术后复发这一难题提供切入点。本课题组在SP细胞耐药理论基础之上提出将ABCG2作为靶点，联合应用姜黄素和低频低强度超声逆转ABCG2介导的胶质瘤SP细胞耐药性这一新的原创方法。我们课题组在已经完成胶质瘤分选并鉴定SP细胞的基础上，进一步深入研究体内外水平有效逆转胶质瘤SP细胞耐药适宜条件，并研究二者单独或联合作用，对其干细胞特性、耐药性和Akt信号通路相关因子影响，明确可能分子机制，最后，观察单独或联合应用对胶质瘤大鼠生存率的影响，为解决恶性恶性胶质瘤高复发率、延长术后患者荷瘤生存期提供新新思路和新方法。

胶质瘤作为脑组织的常见恶性肿瘤，每年夺走中青年人的生命，手术效果不佳，术后放化疗治疗效果不佳，生存期1年左右。干细胞在胶质瘤术后的再发和增殖中发挥重要作用，耐药性得产生是放化疗不佳的主要原因。姜黄素能够抑制胶质瘤干细胞的增殖，并且对其增殖的抑制作用体现出一定的浓度依赖性,随其浓度增加而增强。低频超声对干细胞发挥增殖抑制作用时具有时间和强度依赖性。姜黄素与低频低强度超声联合组对干细胞也有一定的增殖抑制作用。姜黄素能够抑制人脑胶质瘤U87细胞增殖，诱导U87细胞凋亡，逆转耐药蛋白ABCG2的表达；低频低强度超声与姜黄素联合后在抑制U87细胞增殖，诱导细胞凋亡，逆转耐药蛋白ABCG2的表达中作用强度更大，两者联合使用发挥协同作用。降低脑胶质瘤细胞中的Survivin，VEGF和MRP1表达，在脑胶质瘤中VEGF/PI3K/Akt信号通路可能参MRP1表达的调控。对P-gp及JNK的蛋白水平的表达有显著的下调作用；下调JNK蛋白的表达水平后，P-gp蛋白水平的表达也显著下调。可能与抑制Akt活性、FOXO3a的磷酸化和降低MMP-9蛋白表达有关。下调CXCR4的表达，二者联合后发挥协同性的作用。低频低强度超声能够诱导胶质瘤干细胞凋亡，逆转多药耐药蛋白的表达，这一观点为胶质瘤的治疗带来了新的希望和靶点，在未来的治疗中，超声有望作为重要的辅助手段用于胶质瘤的术后治疗，延长患者生存期。