长链非编码RNA HOTAIRM1在结直肠癌中的功能研究

Long noncoding RNAs (lncRNAs) play intrinsic roles as RNA, which may participate in various biological processes through distinct mechanisms. For example, lncRNAs have been implicated in cell cycle control, cell differentiation and apoptosis, while others are involved in epigenetic silencing, transcriptional and translational control, and splicing regulation. Therefore, there is a powerful suggestive link between lncRNAs and disease. But the role of lncRNA in malignant tumor remains unknown. HOTAIRM1 is a novel lncRNA, which was identified recently.We found its expression in colorectal cancer was significantly down regulated. Furthermore, we want to eluciate the biological function of HOTAIRM1 in colorectal cancer by ectopic expression or knockdown of HOTAIRM1. And whether the HOXAIRM1 expression is regulated by aberrant DNA methylation will be studied by MSP and BSP. Otherwise we also want to describe that HOX cluster is the down stream target of HOTAIRM1. Taken together, completion of the study will clarify a new regulation pathway and carcinogenesis mechnism in colorectal cancer and may highlight promising targets of diagnostic and therapeutic value for colorectal cancer in the future.

长链非编码RNA不仅参与了细胞周期、分化、凋亡和衰老，以及细胞间或细胞内核浆运输等细胞学过程，而且还具有表观遗传学调控、转录调节、转录后及翻译调节染色质重塑等重要的分子生物功能。HOTAIRM1是最近新发现的一条长链非编码RNA，本课题组先期实验结果表明HOTAIRM1在结直肠癌中表达明显降低，并且将HOTAIRM1干扰后细胞增殖增加，但其在肿瘤中的生物学机制仍不明确，因此本研究以结直肠癌为疾病模型，以HOTAIRM1为靶点，拟采用表达载体或RNA干扰技术确定其在结直肠癌细胞中的生物学功能；利用MSP和BSP等技术研究HOTAIRM1自身表达是否受甲基化调控及特异性甲基化位点；订制HOX基因簇的低密度芯片，筛选HOXAIRM1下游相关的HOX基因簇成员，采用功能缺失或增补实验进一步明确HOTAIRM1通过HOX基因簇发挥生物学功能；本项目的完成将为结直肠癌的发生发展阐释全新机制。

长链非编码RNA不仅参与了细胞周期、分化、凋亡和衰老，以及细胞间或细胞内核浆运输等细胞学过程，而且还具有表观遗传学调控、转录调节、转录后及翻译调节染色质重塑等重要的分子生物功能。HOTAIRM1是最近新发现的一条长链非编码RNA，本课题组采用逆转录荧光定量PCR方法检测了109例结直肠癌组织和配对正常结直肠粘膜组织样本中HOTAIRM1的表达，发现HOTAIRM1在结直肠癌中的表达明显低于正常对照组织，而HOTAIRM1的表达与患者年龄、性别、肿瘤大小、部位以及TNM分级等临床病理特征无关。收集150例结直肠癌患者和101例健康对照的血浆标本，将其随机分为训练组和确认组，使用巢氏荧光PCR检测血浆中HOTAIRM1水平。采用logistic回归和ROC曲线分析在训练组中确定诊断结直肠癌的临界值为0.003（CRC≤0.003）；在确认组该临界值诊断结直肠癌的灵敏度为64.00%，特异度为76.50%。与目前常用的肿瘤标志物比较，HOTAIRM1诊断结直肠癌的能力与CEA相似，但高于CA125和CA199；将HOTAIRM1与CEA联合使用诊断结直肠癌灵敏度可以提高到84%，而且结直肠癌患者血浆中HOTAIRM1水平与患者年龄、性别、肿瘤大小、部位以及TNM分级等临床病理特征无关，因此血浆中HOTAIRM1水平下降是结直肠癌独立的诊断指标。我们在结直肠癌细胞系中过表达和干扰HOTAIRM1的表达发现HOTAIRM1具有抑制结直肠癌细胞增殖的功能，芯片筛选其下游靶基因结果表明HOTAIRM1通过ECM受体信号相关通路抑制了结直肠癌的发生发展。本项目发现HOTAIRM1可能成为结直肠癌的全新诊断分子标志物而且为阐释结直肠癌发生发展的全新机制奠定了理论基础。