基于STELB抑制同源重组修复的联合用药抗胶质母细胞瘤研究

胶质母细胞瘤致死率很高，仍无理想治疗药物。我们从海绵中分离得到STELB，前期工作表明其具有显著的体内外抗胶质母细胞瘤作用，通过抑制DNA双链损伤同源重组修复诱导癌细胞凋亡。基于该机理，本课题提出与诱导DNA双链损伤的烷化剂替莫唑胺联用可发挥对后者的增敏作用、以及与抑制DNA单链损伤修复的PARP抑制剂奥拉帕尼或卢卡帕尼联用可通过合成致死增强抗肿瘤作用的科学假设。为验证该假设，我们拟首先采用Chou-Talalay法考察两种药物组合的协同抗胶质母细胞瘤细胞SF295和U87增殖的作用，然后利用斑马鱼U87-RFP、裸鼠U87皮下移植瘤和U87-MG-Luc原位移植瘤模型评价体内抗胶质母细胞瘤效果，利用LC-MS测定药物的脑组织分布，还将利用免疫印迹、免疫荧光、同源重组报告基因分析以及免疫组化等手段研究药物联用产生协同作用的机理，为STELB类创新药的研发及抗胶质母细胞瘤应用提供理论依据和实验基础。

Glioblastoma remains to be a highly lethal disease with no satisfying drug. STELB (stellettin B), a compound we isolated from marine sponge Jaspis stellifera, showed potent in vitro and in vivo antiglioblastoma effects, of which the mechanism might be inducing apoptosis via inhibiting DNA DSB (double-strand breaks) homologous recombination (HR) repair in glioblastoma cells. Therefore, we hypothesize that combination of STELB with Temozolomide (TMZ) which causes DNA DSB as a DNA methylated drug might enhance the antiglioblastoma effect, and the combination of STELB with Olaparib or Rucaparib which targets DNA SSB (single strand breaks) repair as a PARP inhibitor might also increase the antiglioblastoma effect by leading to synthetic lethality in tumor cells. To demonstrate these hypotheses, we would first investigate the synergistic inhibition of both combinations against proliferation of glioblastoma SF295 and U87 cells with WST assay and Chou-Talalay analysis. Then, we would examine the in vivo antiglioblastoma efficacy of the 2 combinations, by using zebrafish U87-RFP orthotopic xenograft model, nude mouse U87 subcutaneous xenograft model, and nude mouse U87-MG-Luc orthotopic xenograft model. The passage through blood-brain barrier of the drugs would be demonstrated by measuring the concentration in brain tissues after administration of the 2 combinations. To elucidate the antitumor mechanisms, various assays including immunoblot, immunofluorescence staining, HR reporter assay, as well as immuno-histochemical analysis would be performed. Our study would contribute to the development of STELB or its analogue as innovative antitumor drug, and to the application of such kind of drug in therapy of glioblastoma.