反义长链非编码RNA KB-1683C8调控Metadherin表达促进非小细胞肺癌转移的机制研究

The protein which regulates cell adhesion and cytoskeletal is an important initiation factor in epithelial to mesenchymal transition (EMT) and provides potential target for inhibiting metastasis. Our previous study found that the expression of Metadherin (MTDH) is significantly decreased in non-small cell lung cancer (NSCLC) and was correlated with lymph node metastasis. When the expression of MTDH exogenously decreased in NSCLC cell lines, cell morphology, cell skeleton and migratory ability were changed, suggesting that MTDH might be the initiating factor for EMT. The factor which controls MTDH expression may be the important breakthrough point for inhibiting metastasis in NSCLC. Long non-coding RNA (LncRNA) is demonstrated to inhibit the expression of protein coding gene through a variety of ways, playing an important role in gene expression. We identified an antisense lncRNA KB-1683C8 which located on chromosome 8, the same chromosome with MTDH and shared overlapped sequence with MTDH mRNA. The increased expression of lncRNA KB-1683C8 was revealed in three pairs of NSCLC tissues and corresponding normal tissues through lncRNA chip using RNA seq. Then it is verified by using realtime PCR that the expression of lncRNA KB-1683C8 is increased in NSCLC, and has correlation with the expression of MTDH. The expression of MTDH mRNA was increased when the expression of lncRNA KB-1683C8 was exogenously inhibited by siRNA transfection in NSCLC cells. Here, we give a hypothesis that lncRNA KB-1683C8 suppresses the expression of MTDH and therefore promotes the initiation of EMT. The aim of this research is to verify the relationship between the expressions of lncRNA KB-1683C8, MTDH and EMT, to explore the mechanism involved in the regulation of MTDH expression by lncRNA KB-1683C8, and to prove the correlation through the animal model, providing the basis and evidence for inhibiting metastasis in NSCLC.

调节细胞粘附和细胞骨架的蛋白是上皮间质转化（EMT）的重要启动因子，是抑制肿瘤转移的靶点。我们已证实非小细胞肺癌（NSCLC）中异粘蛋白Metadherin（MTDH）调节细胞粘附和细胞骨架启动EMT，调控其表达的因子可能为抑制转移的突破点。长链非编码RNA（lncRNA）通过多种途径抑制编码蛋白基因表达发挥重要作用。我们发现反义lncRNA KB-1683C8与MTDH同位于8号染色体且序列不完全重叠，lncRNA芯片及qPCR均验证此lncRNA在NSCLC中表达增高，进一步证实外源性抑制该lncRNA可提高MTDH mRNA表达。因此我们提出：lncRNA KB-1683C8抑制MTDH从而启动EMT促进NSCLC转移。本研究将验证lncRNA KB-1683C8与MTDH的相关性，证实lncRNA、MTDH及EMT的关系，并探索其调节机制，为抑制NSCLC转移提供理论依据和基础。

调节细胞粘附和细胞骨架的蛋白是上皮间质转化（EMT）的重要启动因子，是抑制肿瘤转移的靶点。我们已证实非小细胞肺癌（NSCLC）中异粘蛋白Metadherin（MTDH）调节细胞粘附和细胞骨架启动EMT，调控其表达的因子可能为抑制转移的突破点。长链非编码RNA（lncRNA）通过多种途径抑制编码蛋白基因表达发挥重要作用。我们发现反义lncRNA KB-1683C8与MTDH同位于8号染色体且序列不完全重叠，lncRNA芯片及qPCR均验证此lncRNA在NSCLC中表达增高，进一步证实外源性抑制该lncRNA可提高MTDH mRNA表达。进一步检测发现linc00673可能发挥作用：linc00673水平在NSCLC组织中上调；体外实验证实其能影响NSCLC细胞系的增殖能力和周期进程，体内实验发现降低linc00673表达能有效抑制皮下瘤体积和重量。并且linc00673能影响NSCLC细胞的迁移和侵袭，利用尾静脉注射发现降低linc00673表达量能有效抑制肺转移结节。生物信息学及进一步实验发现linc00673与EZH2相互作用，而当EZH2表达下降时，HOXA5水平相应改变。RIP和CHIP试验进一步分析， NSCLC细胞中linc00673与EZH2直接结合，EZH2可能与HOXA2启动子区域相结合。另外课题组在试验过程中发现，MTDH表达改变则NSCLC细胞对多西他赛的耐药性变化。流式细胞结果发现MTDH可能通过抑制细胞凋亡导致耐药。结果表明，调控MTDH表达再经多西他赛处理，促凋亡基因Bax及抑制凋亡基因Bcl-2表达水平相应改变。进一步发现p-Akt蛋白表达同样改变。综上，课题组对MTDH调控NSCLC侵袭和转移的机制进行了探索，并且在耐药方向进行了初步的检测，为NSCLC的转移及耐药提供一个治疗靶点。