长链非编码RNA DCST1-AS1促进三阴性乳腺癌侵袭转移的机制研究

DCST1-AS1 (referred to as DC) is a triple negative breast cancer (TNBC) -related lncRNA obtained by high-throughput chip and TCGA data. There is no report about the biological function of DC. In the previous experiments, we confirmed that there was a positive correlation between DC and TNBC distant metastasis and histopathological grading. DC detection has high diagnostic efficiency. Silencing DC can inhibit TNBC cell proliferation, invasion and metastasis. c-MYC can promote DC expression. DC binds to ANXA1 protein. DC can competitively bind to miR-873 to facilitate downstream gene translation. Therefore, we propose such a scientific hypothesis: DC can promote the invasion and metastasis of TNBC by binding ANXA1 to activate TGF-β / Smad and NF-κB signaling pathway and competitively binding miR-873 to promote IGF2BP1 expression to form a positive feedback loop. This project intends to confirm that DC can promote TNBC invasion and metastasis in vitro and in vivo. We will design rescue experiments and nucleic acid-protein interaction experiments to clarify the molecular mechanism of DC promoting TNBC invasion and metastasis, and evaluate the correlation between DC and c-MYC, ANXA1, miR-873, IGF2BP1 in clinical samples. TNBC is in urgent need of effective molecular targets and this study may provide new insights into TNBC therapy.

DCST1-AS1(简称DC)是根据高通量芯片及TCGA数据获得的三阴乳腺癌(TNBC)相关lncRNA，目前尚无DC的生物学功能报道。前期研究发现：DC与TNBC远端转移及病理组织学分级正相关；DC检测的诊断效率高；干扰DC可抑制TNBC细胞的侵袭转移；DC表达受c-MYC调控；DC可绑定ANXA1蛋白；DC可竞争结合miR-873。故提出DC受c-MYC调控，通过绑定ANXA1激活TGF-β/Smad和NF-κB信号通路、竞争结合miR-873促进IGF2BP1表达并形成正反馈回路，共同促进TNBC侵袭转移的科学假说。本项目拟在体内外实验中证实DC可促进TNBC侵袭转移；设计拯救实验、核酸蛋白互作实验等阐明DC促进TNBC转移的分子机制；临床评价DC与c-MYC、ANXA1、miR-873、IGF2BP1之间的相关性。TNBC治疗急需有效的分子靶标，本研究可为TNBC防治提供新思路。

TNBC侵袭程度高、易远处转移，缺乏有效的治疗靶点，是乳腺癌中预后较差的亚型。LncRNA因其广泛的基因调控功能、组织特异性和条件特异性的表达模式，具备成为临床生物标志物和治疗靶标的潜能，是近年来国际肿瘤研究的前沿热点。DCST1-AS1是我们用lncRNA芯片在TNBC组织中筛选获得的上调表达的功能未知的长链非编码RNA。我们利用生物信息学工具分析得知DCST1-AS1无蛋白编码能力；用FISH技术明确DCST1-AS1分布于胞核和胞质中；结合临床资料证实DCST1-AS1表达与组织病理学分级和转移有关；DCST1-AS1促进TNBC细胞的增殖、迁移和侵袭，并受到癌性转录因子MYC的调控；DCST1-AS1与miR-873-5p结合后被降解，这种结合上调了miR-873-5p的靶蛋白IGF2BP1及其下游相关蛋白的表达，并借此与MYC形成正反馈回路。DCST1-AS1通过结合ANXA1调控TGF-β/Smad信号通路，影响细胞的EMT过程和对化疗药物的抗性。DCST1-AS1还可分别与ALDOA和ENO1结合促进TNBC细胞的增殖和侵袭。总之，本研究阐明了DCST1-AS1的上游调控机制和下游功能途径，从lncRNA角度为TNBC肿瘤的分子治疗提供了新的靶点。此外，我们还发现miR-200c/141-3p宿主基因编码的lncRNA MIR200CHG可与多功能蛋白YB-1在乳腺癌细胞内稳定结合，通过调节YB-1蛋白的泛素化和磷酸化来促进乳腺癌的恶性进展，为乳腺癌分子治疗提供了另一个潜在靶标。