线粒体转录因子A在肝细胞肝癌生长及转移过程中作用机制的研究

Hepatocellular carcinoma is one of the most common malignant tumors, which grows rapidly and tends to metastasize with serious adverse prognosis. The current mechanism of hepatocellular carcinoma growth and metastasis is still unclear. Studies showed that mitochondrial transcription factor A (mtTFA) played an important role in cancer development and progression, mtTFA highly expressed in prostate cancer, pancreatic cancer, colon cancer and other malignant tumors, and was negatively correlated with clinical outcome; Recent research found mtTFA regulated transcription of mitochondrial gene and nuclear genes in tumor cells. However, the role of mtTFA in hepatocellular carcinoma metastasis is still not clear, particularly the research on direct downstream target genes of mtTFA and their function. In our previous study, it showed that mtTFA highly expressed in the tissue of hepatocellular carcinoma, and the expression positively correlated with degree of malignancy; we further found that mtTFA overexpression enhanced hepatocellular carcinoma cell proliferation and invasion; We first found mtTFA bound to the promoter sequence of IF1 and regulated IF1’s transcription, and further regulated the expression of IF1 in hepatocellular carcinoma. Therefore, we hypothesized that mtTFA participated in the growth and metastasis of hepatocellular carcinoma and could play an important role, we also proposed that mtTFA or a combination of mtTFA with IF1 was a novel marker in the prognosis of HCC and a potential therapeutic target.

肝细胞肝癌是消化系统最常见恶性肿瘤之一，由于其生长快速且易发生肝内外转移，多预后不良，目前肝细胞肝癌生长及转移机制不清楚。研究发现线粒体转录因子A（mtTFA）在恶性肿瘤发生发展过程中发挥重要作用，mtTFA在前列腺癌、胰腺癌等恶性肿瘤组织中高表达，且与临床预后呈负相关；最新研究证实mtTFA在肿瘤细胞中不仅调控线粒体基因转录，且参与核内基因转录调控。然而，mtTFA在肝细胞肝癌发生发展方面研究尚属空白，特别是mtTFA在肝细胞肝癌中直接调控的下游靶基因不清楚。本课题前期研究发现mtTFA在肝细胞肝癌中呈高表达，且随着恶性程度增高其胞浆及胞核表达均增加；异位高表达mtTFA增强肝癌细胞增殖及侵袭能力；首次发现mtTFA与IF1基因启动子结合并调控其转录与表达。因此，我们推测mtTFA通过调控IF1表达在肝细胞肝癌生长及转移方面可能发挥重要作用，为肝癌患者提供新的预后因子和治疗靶点。

项目背景：.肝细胞肝癌是消化系统最常见恶性肿瘤之一，由于其生长快速且易发生肝内外转移，多预后不良，目前肝细胞肝癌生长及转移机制不清楚。研究发现线粒体转录因子A（mtTFA）在恶性肿瘤发生发展过程中发挥重要作用，mtTFA在前列腺癌、胰腺癌等恶性肿瘤组织中高表达，且与临床预后呈负相关；最新研究证实mtTFA在肿瘤细胞中不仅调控线粒体基因转录，且参与核内基因转录调控。然而，mtTFA在肝细胞肝癌发生发展方面研究尚属空白，特别是mtTFA在肝细胞肝癌中直接调控的下游靶基因不清楚。.主要研究内容：.免疫组化、蛋白免疫印迹和实时定量PCR检测mtTFA在肝细胞肝癌患者肿瘤组织中的表达情况，并结合肝癌患者的临床病理学资料分析mtTFA表达与肝细胞肝癌患者预后的关系；应用划痕实验、迁移和侵袭实验以及裸鼠肝脏原位肿瘤及肺转移模型来验证mtTFA对肝细胞肝癌侵袭转移方面的影响；CHIP-seq检测提示mtTFA可结合到lncRNA-RMRP、EPHA6及MTRNR2L2等基因转录子上，初步PCR结果证实mtTFA能促进其基因的转录。.重要结果及关键数据：.免疫组化检测mtTFA在肝细胞肝癌患者肿瘤组织中的表达情况，并结合肝癌患者的临床病理学资料分析mtTFA表达与肝细胞肝癌患者预后的关系，证实mtTFA的表达在肝细胞肝癌中显著升高且与预后呈负相关；体外细胞学实验及体内裸鼠模型来共同验证了mtTFA在肝细胞肝癌生长、侵袭和转移过程中所起到的重要作用；CHIP-seq检测提示mtTFA可结合到lncRNA-RMRP、EPHA6及MTRNR2L2等基因转录子上，初步PCR结果证实mtTFA能促进其基因的转录，证实mtTFA可能通过调整这些基因促进肝癌发生发展。.科学意义：.研究证实mtTFA是肝细胞肝癌发展和转移过程中的一个关键调节控制因子，它控制着肝细胞肝癌发展和转移过程中的多个重要方面。研究确定了mtTFA的高表达可以促进肝细胞肝癌的生长、侵袭和转移。另外，我们发现了一个新的调控肝细胞肝癌进展的机制是由mtTFA及其下游靶基因共同调控。根据以上数据提出mtTFA或mtTFA联合其下游靶基因将成为一种新的评估肝细胞肝癌患者预后的标记物和治疗的肝细胞肝癌的潜在靶点。