lncRNA LINC02418募集SRSF3调控PDCD4 mRNA可变性剪接促进结直肠癌转移的机制研究

The main cause of death in colorectal cancer (CRC) patients was tumor invasion and metastasis. Recently, it has been found that lncRNA was involved in the invasion and metastasis of CRC by regulating the alternative splicing (AS) process of different precursor messenger RNA. In our previous study, we found that LINC02418 is specific increased in CRC. High LINC02418 expression could promote the invasion and metastasis of CRC cells. Using lncRNA chip high throughput analytical technique, we found that PDCD4 was highly expressed after knockdown LINC02418, and the expression of PDCD4 subtype 2 was regulated by both LINC02418 and p-SRSF3. The RIP experiments have confirmed that LINC02418 could bind to SRSF3 protein. So, we hypothesized that LINC02418 could promote CRC metastasis by recruitting the SRSF3 protein and activating the phosphorylation of SRSF3, and further regulating the AS of PDCD4 mRNA. This study will explore the regulatory effect of LINC02418 on AS process of PDCD4 mRNA using ChIP, RIP, RNA-pulldown, and etc. All the findings could reveal the underlying regulatory mechanism of LINC02418 in the CRC metastasis and provide more research and theoretical basis for metastatic CRC prevention and diagnosis.

结直肠癌（CRC）的侵袭转移是患者死亡的主要原因。新近研究发现lncRNA通过调控不同前体mRNA的可变性剪接（AS）参与CRC的侵袭转移。本课题组发现lncRNA LINC02418在CRC中特异性高表达，促进CRC细胞的侵袭转移，同时高通量测序发现敲低LINC02418后PDCD4显著高表达，且PDCD4亚型2的表达水平同时受LINC02418及p-SRSF3的调控，RIP实验已证实LINC02418与SRSF3绑定。据此提出假设：在CRC中LINC02418募集SRSF3蛋白，促进SRSF3的磷酸化水平，调控PDCD4 mRNA的AS，促进CRC的转移。本课题以LINC02418为切入点，采用ChIP、RIP、RNA-pulldown等技术，探索其对PDCD4 mRNA的AS的调节作用，揭示其促进CRC转移的分子机制，为转移性CRC的预防和诊断提供部分研究基础和理论依据。

结直肠癌（CRC）的侵袭转移是患者死亡的主要原因。新近研究发现lncRNA通过调控不同前体mRNA的可变性剪接（AS）参与CRC的侵袭转移。本课题组研究发现在CRC中lncRNA linc02418特异性高表达，促进CRC细胞的侵袭转移，同时高通量测序发现敲低linc02418后PDCD4显著高表达，且PDCD4亚型2的表达水平同时受linc02418及p-SRSF3的调控。分子机制研究发现在CRC中特异性高表达的linc02418，可以募集SRSF3蛋白，促进SRSF3的磷酸化水平，调控PDCD4 mRNA的AS，促进CRC的转移。此外，基于生物信息学分析，本课题组还发现lncRNA linc02231在CRC组织及细胞中高表达。我们进一步验证了linc02231对CRC细胞增殖、迁移和血管生成的影响。体内外实验证实敲低linc02231可显著抑制CRC肿瘤的生长和转移。通过荧光素酶实验证实，转录因子STAT2与linc02231结合。进一步的分子机制研究显示由STAT2诱导的linc02231通过miR-939-5p-hnRNPA1轴调控ANGPTL4的AS，促进CRC的侵袭转移。本课题以转移性CRC为研究对象，分别在细胞、动物及临床样本水平进行验证，探索lncRNA其对下游靶基因mRNA的AS的调节作用，揭示其促进CRC转移的分子机制，为转移性CRC的预防和诊断提供部分研究基础和理论依据。