原癌基因CT45A1激活Src促进宫颈癌转移的机制

Cervical cancer metastasis is the leading cause of death in patients, but the mechanism is not clear. As cancer testis antigen, CT45A1 promotes the development of malignant tumors for its abnormally high expression. Our previous study found that CT45A1 is aberrantly overexpressed in cervical cancer patients, accelerating migration, invasion and metastasis of cervical cancer cells, and activates the non-receptor tyrosine kinase Src, which activates the transcription factor CREB. Then, does CT45A1 promote cervical cancer metastasis by activating Src? What’s the mechanism? Based on this, we propose a hypothesis: CT45A1 can increase cervical cancer metastasis by activating Src and CREB signaling pathway to upregulate metastatic genes. Around this hypothesis, we will achieve the following two goals: 1) we will confirm CT45A1 activates Src to drive cervical cancer metastasis by shRNA and orthotopic models; 2) we will clarify the mechanism of CT45A1 phosphorylated Src and molecular mechanism of transcription factor CREB enhanced metastatic genes, using kinase assay, co-immunoprecipitation, DNA microarray, CHIP and other technologies. Finally, the mechanism of CT45A1 promoting cervical cancer metastasis will be revealed. We expect this research will make breakthroughs in cervical cancer metastasis mechanism, and providing new ideas and targets in diagnosis and treatment.

宫颈癌转移是患者死亡的主要原因，但其转移机制不明。原癌基因CT45A1属癌睾抗原，其异常高表达促进恶性肿瘤的发生发展。申请人前期研究发现，CT45A1在宫颈癌病人中异常高表达，促进宫颈癌细胞迁移、侵袭和转移，并激活非受体酪氨酸激酶Src，进而活化转录因子CREB。那么，CT45A1是否通过激活Src促进宫颈癌转移？其机制是什么？据此，我们提出假说：CT45A1通过激活Src，活化转录因子CREB，启动下游转移基因高表达促进宫颈癌转移。围绕该假说，本项目旨在：1）通过shRNA和宫颈癌原位动物模型证实CT45A1通过激活Src促进宫颈癌转移；2）使用激酶实验、免疫共沉淀和基因芯片、CHIP等技术分别阐明CT45A1激活Src的机制和下游转录因子CREB启动转移关键基因高表达的分子机制。最终揭示CT45A1促进宫颈癌转移的机制。以期为突破宫颈癌转移机制瓶颈和转移性宫颈癌诊疗提供新思路和新靶标。

宫颈癌转移是患者死亡的主要原因，但其转移机制不明。原癌基因CT45A1属癌睾抗原，其异常高表达与恶性肿瘤的发生发展呈正相关。本项目首先在临床宫颈癌病人样本中发现CT45A1作为癌睾抗原在宫颈癌组织中呈异常高表达；随后在细胞水平上，我们发现CT45A1高表达使两株宫颈癌细胞的迁移和侵袭都增加了约3倍和3-5倍；反之CT45A1基因沉默，宫颈癌细胞的迁移和侵袭分别降低了约1.6和3.7倍；动物实验结果显示，对照组荷瘤小鼠肿瘤质软且边界明显，CT45A1高表达后肿瘤组织质地坚硬，且50%小鼠出现侵入覆膜的现象。这些结果表明CT45A1增强宫颈癌细胞的侵袭和转移。分子机制水平上，我们发现：1）CT45A1促进纤维粘连蛋白FN1转录从而促进FN1蛋白表达，进而激活FN1-SRC通路；2）同时CT45A1又与SRC蛋白相互作用并促进SRC的磷酸化，进而调控下游ERK-CREB通路，进而导致下游癌基因的转录；由此，最终导致CT45A1促进宫颈癌细胞恶性演化和转移。我们的研究为宫颈癌恶性演变和转移机制提供了新见解，也为CT45A1作为新的宫颈癌肿瘤诊断的标志物奠定了基础，具有重要科学意义和潜在临床应用价值。