原发性脑肿瘤STAT3 信号通路负调控因子的生物学功效与白藜芦醇个体化治疗研究

Medulloblastoma/MB and gliaoblastoma/GBM are the most common primary brain malignancieswith high death rates. So far, no effective therapeutic approaches for them has been available. It hasbeen recognized that activated STAT3 signaling is critical for the growth and survival of these two kinds of cancers. We found that resveratrol/Res exerted its anti-MB activity via inhibiting STAT3.expression and its signaling; furthermore, the effectiveness of Res was largely correlated with the status of STAT3 activation and/or the sensitivities of this signaling to Res treatment. It has been known that three factors/NRFs can negatively regulate STAT3 signaling, which include Protein tyrosine phosphatase/PTP, Suppressors of cytokine signaling/SOCS and Protein inhibitors of activated STAT3/PIAS3. Nevertheless, the expression statuses, biological functions and relevance with chemosensitivity of these three factors in human primary brain malignancies remain abscure. This proposal thus aims to address the following issues: 1) profiling the expression patterns of the three factors in MBs, GBMs, the tumor-surrounding brain specimens and normal rat brain tissues/cultured cells and then analyzing their correlation with STAT3 activation; 2) evaluation of the impacts of Res on the expression of NRFs and their relevance with drug efficacy; 3) determining the influence(s) of RNAi-mediated inhibition of NRF expression in the biological behaviors and resveratrol sensitivity of MB and GBM cells; 4) elucidating whether inhibition of one of NRFs brings about alteration of gene expression patterns to the other two factors; 5) shedding light on the main reason leading to STAT3 activation and the major molecular target(s) of resveratrol; 6) evaluating the therapeutic value of NRF regulation using a rat in situ transplanted brain tumor model treated with resveratrol in unique route. Finally, comprehensive analyses will be conducted on the total results to determine the significance of NRFs and their regulation in resveratrol-based personalized therapy for primary brain malignancies.

髓母细胞瘤/MB和胶质母细胞瘤/GBM是最常见的原发性脑肿瘤/脑瘤，迄今疗效不佳,而STAT3通路对两者至关重要。白藜芦醇/Res的抗脑瘤作用主要通过抑制STAT3通路，其效果与该通路活化和药物反应有关。STAT3通路负调控因子/NRFs有三：蛋白酪氨酸磷酸酶、细胞因子信号抑制因子和STAT3活化抑制蛋白。三者在脑瘤中的状态和与药物敏感性关系尚无报道。本项目拟系统研究：1）NRFs在人类脑瘤及其细胞系、非癌和正常鼠脑组织的表达情况及其对STAT3活化的影响；2）Res对NRFs表达的影响及与药效关系；3）干扰NRFs表达并观察生物学与Res敏感性变化；4）调节NRFs之一能否引起其余二个表达改变；5）导致脑瘤STAT3活化的主因和Res关键作用靶点；6）建立大鼠脑原位移植瘤白藜芦醇治疗模型，观察调节NRFs有无药物增效作用。最后，综合评估NRFs和Res在原发性脑肿瘤个体化治疗方面的价值。

髓母细胞瘤/MB和胶质母细胞瘤/GBM是最常见的原发性脑肿瘤，其治疗方式为手术辅以术后放化疗。尽管在手术和术后治疗方式上不断改进，但迄今为止此类肿瘤的疗效仍然很差。包括本课题组在内研究结果显示，STAT3介导的信号通路对胶质和髓母细胞瘤的生长至关重要。我们还发现，STAT3通路是白藜芦醇/Res的关键分子靶点，即白藜芦醇的抗脑瘤作用主要通过抑制STAT3通路，其效果与该通路活化和药物反应有关。不过，对白藜芦醇抑制STAT3通路的内在机制却有待探讨。STAT3通路的活性可被正向或负向调节。有关促进原发性脑瘤中该通路活化的因素早有报道，如IL-6, LIF,IL-8等，但STAT3通路负性调控因子状态却极少报道。STAT3通路的主要负调控因子/NRFs有三：蛋白酪氨酸磷酸酶、细胞因子信号抑制因子和STAT3活化抑制蛋白。三者在脑瘤中的状态和与药物敏感性关系尚无报道而这则是本项目要阐明的学术问题。.本项目的研究结果显示：1）与非癌和正常鼠脑组织相比，NRFs在人类脑瘤及其细胞系中表达普遍下调且与STAT3活化相关[Mol Med Rep, in press；Nutrients, in press]；2）Res对NRFs表达具有上调作用，其中对PIAS3的失调作用更为明显[Cancer Chemoth Pharmacol. 2013; Neurotherapeutics, 2015; Oncotarget, 2015]；3）干扰SOCS3表达可影响Res对髓母细胞瘤神经元样分化趋势但不影响白藜芦醇的抗癌作用和其它两个被测NRF 的表达[Nutrients, in press]；4）NRFs是导致脑瘤及其它类型癌症STAT3活化的主要原因而STAT3是Res的关键分子靶点[Genes Cancer, 2014; J Ovarian Res, 2015; Gynecol Oncol, 2015; Cell Death Discovery, 2016]；6）通过大鼠脑原位移植瘤白藜芦醇治疗模型，发现调节NRFs对Res的治疗效果无明显影响，进一步证明Res的抗癌作用具有多靶点特征。.综上所述，NRFs与STAT3的活化状态负相关，故可作为评估原发性脑肿瘤预后的新指标；Res对所测三种NRFs表达的促进作用为其实际应用提供新的科学依据和实验佐证；SOCS3在神经元样分化和神经元