细胞缝隙连接蛋白43半通道介导三氧化二砷与膀胱癌卡介苗免疫治疗间交互调控机制的研究

Recent studies have further demonstrated that intravesical Bacillus Calmette-Guérin (BCG) immunotherapy is a highly effective treatment for bladder transitional cell carcinoma.The mechanism of treatment is the local immune response involving more steps. BCG combined to chemotherapy drugs or other agents can enhance the curative effect, but the mechanism is not clear. BCG immunotherapy results in neutrophil recruitment and subsequent IL-6 secretion in initial immune process after intravesical perfusion. Previous work has demonstrated IL-6 also contributed to the regulation of opening of Cx43 hemichannels.The up-regulation of Cx43 transcription and hemichannel open can be induced by oxidative stress. As2O3 may affect the Cx43 transcription and hemichannel open and then inrease the outflow of intracellular GSH.The oxidative stress induced by As2O3 can affect Cx43 hemichannel open and down-regulated intracellular GSH can promote oxidative stress which can improve anti-tumor effect of As2O3. The opening of Cx43 hemichannels further increases IL-6 expression to strengthen BCG immune response and IL-6 can further induce the opening of Cx43 hemichannels.Based on the above, the applicant made the following assumption that oxidative stress of As2O3 may affect the the hemichannel open,metabolism of As2O3 and IL-6 expression in bladder transitional cell carcinoma. There is mutual adjustment between IL-6 expression and Cx43 hemichannel open.Cx43 hemichannels is supposed to play an important role in coordination of BCG with As2O3.Therefore,we propose to transfect bladder transitional carcinoma cells with Cx43 gene. These cells will be used to investigate the potential role of the opening of Cx43 hemichannels in charge of intracellular GSH and IL-6 in bladder carcinoma treated by BCG combined to As2O3.Accomplish of this proposal will enhance the understanding on the role of Cx43 hemichannels in treating bladder cancer with BCG, As2O3 and the interaction between the two mechanisms. It will provide theoretical basis of optimising more efficient therapeutic strategy in combination of BCG with As2O3,in addition, might help to improve designing appropriate combination therapies against bladder cancer.

BCG膀胱灌注是浅表性膀胱癌免疫治疗的金标准，但部分病人疗效差，不能耐受毒性。寻找与之联用以提高疗效减少副作用的药物是函待解决的问题。我们已发现As2O3治疗膀胱癌有效，核心机制为氧化应激反应，已知氧化应激反应可促进Cx43半通道开放，半通道的开放可上调细胞因子IL-6的表达。据此提出Cx43半通道可介导As2O3上调BCG免疫反应中关键因子IL-6的表达提高疗效。本课题拟通过观察BCG与As2O3对膀胱癌细胞Cx43表达和半通道开放的影响，并检测IL-6等相关小分子改变，来进一步明确二者对膀胱癌作用的新机制及两者间的交互调节。论证Cx43半通道作为BCG免疫反应及As2O3诱导氧化应激两个抗肿瘤机制的交叉点，可通过调节其开放使两种药物产生协同效应，互相增强抗肿瘤效果的假说。可为BCG联合As2O3治疗膀胱癌提供理论基础，有助于制定科学合理的灌注方案，提高治疗膀胱癌的效果。

BCG膀胱灌注是浅表性膀胱癌免疫治疗的金标准，但因其毒性较大，很多人无法耐受治疗，寻找与之联用以提高疗效减少副作用的药物成为函待解决的问题。我们已发现As2O3治疗膀胱癌有效，核心机制为氧化应激反应，已知氧化应激反应可促进Cx43半通道开放，半通道的开放可上调细胞因子IL-6的表达。据此提出Cx43半通道可介导As2O3上调BCG免疫反应中关键因子IL-6的表达提高疗效。本研究中，我们发现As2O3可以诱导缝隙连接蛋白43（Cx43）蛋白与mRNA表达，同时增强其功能。卡介苗处理的膀胱癌细胞可释放大量IL-6，而这两个药物同时应用时可形成Cx43和IL-6之间一个反馈环，因此低剂量药物的药物浓度便可引起膀胱癌细胞的凋亡。因此我们认为Cx43半通道作为BCG免疫反应及As2O3诱导氧化应激两个抗肿瘤机制的交叉点，可通过调节其开放使两种药物产生协同效应，互相增强抗肿瘤效果。可为BCG联合As2O3治疗膀胱癌提供理论基础，有助于制定科学合理的灌注方案，提高治疗膀胱癌的效果。