STIM1相关信号通路调控结直肠癌转移机制研究

Metastases are the leading cause of relapse and death of colorectal cancer patients, and its mechanisms are still unclear. As the ubiquitous intracellular signal transduction composition, Ca2+ plays an important role in the development and progression of tumors. In nonexcitable cells, especially the tumor cells, store-operated Ca2+ entry (SOCE) is the predominant Ca2+ entry mechanism. It has now been confirmed that STIM1 is one of the most important compositions of SOCE. Our previous studies indicate that STIM1 is highly expressed in metastatic colorectal cancer tissues and colorectal cancer cells with higher metastasis potential, and plays a promoting role in tumor cell metastasis. We also found that there may be multiple regulatory relationships between miR-185, EGR1 and STIM1 which may be the cause of the dysregulated STIM1. In this project we will use CHIP, EMSA and gene reporter systerm to further test and verify the multiple regulation of STIM1. Moreover, we will use patch clamp, calcium imaging, truncation /mutation, stimulant/ inhibitor and other experimental method to study the role of SOCE and Ca2+ in the colorectal cancer metastasis promoted by STIM1. And clear Is there any non-SOCE functionality mode of STIM1. Together, the current project will provide a novel theory and empirical basis for the treatment of colorectal cancer.

转移是导致结直肠癌患者复发和死亡的主要原因，其机制尚不明确。钙离子作为细胞内最普遍的信号转导成分在肿瘤发生发展过程中有着重要作用。钙池操纵的钙进入(SOCE)是非兴奋细胞特别是肿瘤细胞最主要的钙离子进入机制，现已证实STIM1是触发SOCE最关键的功能分子之一。我们前期的研究证实STIM1在发生转移的结直肠癌临床组织以及高转移潜能结直肠癌细胞系中高表达，发挥着促转移作用，并发现miR-185/EGR1/STIM1之间可能存在的多重调控关系是STIM1表达失调的原因。本项目将通过CHIP,EMSA,荧光报告基因等实验进一步研究验证STIM1的多重调控机制。通过膜片钳、钙离子成像技术，截短/突变、兴奋/抑制实验等深入探讨SOCE及钙离子在STIM1促结直肠癌转移过程中所发挥的作用，并明确STIM1是否存在非SOCE的功能模式，为干预结直肠癌转移提供新的理论依据和实验基础。

转移是导致结直肠癌患者复发和死亡的主要原因，阐明其调控的分子机制将有助于结直肠癌的精准诊断与治疗。在本项研究中，我们首先证实了STIM1在高侵袭性结直肠癌细胞中呈高表达，在结直肠癌组织中的检测结果提示STIM1的表达要高于对应的癌旁组织，其表达水平与肿瘤的淋巴结转移及TNM分期相关，STIM1阳性的结直肠癌患者的预后要差于STIM1阴性的患者。其次，我们通过体内、体外实验探讨了STIM1的功能活性，结果显示过表达STIM1可以促进结直肠癌细胞发生EMT变化，增强其侵袭转移能力，而沉默其表达则减弱其相应的功能。为进一步探讨STIM1表达的调控机制，我们运用网络的靶分子分析工具及基于我们前期的研究工作，筛选出miR-185做为我们研究的靶分子。通过实验我们证实结直肠癌中miR-185的表达与结直肠癌的转移潜能呈负相关，与STIM1的表达呈负相关，miR-185通过转录后调控机制调节了STIM1的表达，从而调控了结直肠癌的转移。综上，我们的研究提示miR-185–STIM1调控轴与结直肠癌的转移密切相关，有可能成为判断预后或者开发新型抗转移治疗的潜在靶标。