JMJD2C激活MALAT1/β-catenin信号通路调控大肠癌转移的机制及健脾解毒方对其作用研究

Invasion and metastasis is one of the main reasons why therapies fail in treating colorectal cancer (CRC). Long non-coding RNA MALAT1 has been recently found to regulate invasion and metastasis of CRC cells. We previously reported that MALAT1 enhanced nuclear translocation of β-catenin resulting in increased cancer cell metastasis, while dissociating heterodimer SFPQ/PTBP-2 to release PTBP-2. We also showed that TCM Jianpi Jiedu Recipe (JPJDR) inhibited MALAT1 expression as well as decreased CRC metastasis, however, the upstream mechniasm of MALAT1 is still unclear. Basing on the effect of histone demethylase JMJD2C on the activity of gene promoter, as well as our preliminary experiment results, we postulate the JMJD2C activates MALAT1/β-catenin signaling pathway as one of the main mechanisms regulating CRC metastasis. We propose to apply the technology like CRISPER/cas9 gene editing, Chromatin Immunoprecipitation-sequencing, to delineate this aforementioned mechanism that JMJD2C activates MALAT1/β-catenin signaling pathway. To establish nude mouse liver/lung metastasis models and orthotopic tumor models, and we will further substantiate the inhibitory effect of JPJDR on JMJD2C mediated MALAT1/β-catenin signaling pathway, consequently decreasing CRC metastasis. Our study will shed light on the mechanisms by which CRC cells metastasize, and equally importantly, provide scientific foundation for using TCM to prevent and treat colorectal cancer.

侵袭转移是大肠癌治疗失败的重要原因之一，最近研究发现长链非编码RNA-MALAT1参与调控大肠癌的侵袭转移。我们前期研究发现MALAT1通过下游SFPQ/PTBP-2介导的β-catenin核转运促进侵袭转移；健脾解毒方通过下调MALAT1抑制侵袭转移，但MALAT1的上游调控机制尚不清楚。鉴于去甲基化酶JMJD2C可以调控基因启动子活性，结合预实验结果，我们提出：JMJD2C通过激活MALAT1/β-catenin信号通路促进大肠癌侵袭转移的假说。本课题采用CRISPER/cas9基因编辑，染色质免疫共沉淀-测序等技术，揭示JMJD2C激活MALAT1/β-catenin信号通路促进大肠癌侵袭转移的机制；并建立裸鼠肝肺转移和原位移植瘤模型，利用体内和体外实验研究健脾解毒方通过JMJD2C调控MALAT1/β-catenin通路抑制大肠癌侵袭转移的机理，为中医药防治大肠癌转移提供科学依据。

复发转移是大肠癌治疗失败的重要原因之一。前期研究发现长链非编码RNA-MALAT1参与调控大肠癌的侵袭转移，并且MALAT1可以通过下游SFPQ/PTBP-2介导的β-catenin核转运促进大肠癌侵袭转移，但MALAT1的上游调控机制尚不清楚。长期的临床和基础研究表明，中药复方健脾解毒方在临床治疗中具有良好的抗肿瘤效果，并且健脾解毒方可以通过调节上述信号通路抑制大肠癌侵袭转移。鉴于去甲基化酶JMJD2C可以调控基因启动子活性，本课题采用CRISPR/cas9基因编辑，染色质免疫共沉淀-测序等技术，揭示JMJD2C激活MALAT1/β-catenin信号通路促进大肠癌侵袭转移的机制；并建立裸鼠转移和移植瘤模型，研究健脾解毒方通过JMJD2C调控MALAT1/β-catenin通路抑制大肠癌生长和侵袭转移的机理。研究结果表明：（1）大肠癌转移灶组织中JMJD2C和MALAT1表达均高于原发灶，并且二者的表达成正相关；原发灶和转移灶组织标本中MALAT1启动子区域H3K9me3和H3K36me3甲基化水平相比于癌旁组织明显降低；JMJD2C和MALAT1高表达患者其总生存期也明显降低。（2）JMJD2C通过调节MALAT1基因启动子活性促进MALAT1基因的表达，继而激活MALAT1/β-catenin信号通路促进大肠癌侵袭转移。（3）健脾解毒方通过JMJD2C介导的MALAT1/β-catenin通路抑制大肠癌细胞的生长和侵袭转移。本研究结果，一方面初步阐释了JMJD2C和MALAT1的临床诊断和预后的研究价值；另一方面也深入揭示了去甲基化酶JMJD2C对MALAT1的关键调控机制；最后详细阐述了健脾解毒方的抗肿瘤作用跟表观遗传学调控和非编码RNA的调控有着重要的联系。本研究成果将为健脾解毒方广泛应用于临床大肠癌的防治提供重要的科学依据。