LncRNASNHG15和miR-451交互作用参与人肺腺癌EGFR-TKI耐药调控的分子机制研究

Chemoresistance is the most significant obstacle of the clinical efficacy by TKI target treatment in lung adenocarcinoma nowadays. The mechanism involved in epigenetics change and aberrant key signaling regulation, as well as genetic transform in multiple drug resistance ralted protein. On the previous basis of establishment of EGFR-TKI-resistant lung adenocarcinoma cell lines, our group has investigated that aberrant activation of Notch-1, one of the improtant receptor in Notch signaling pathway, may be involved in the phenotype of TKI-resistant in lung adenocarcinoma. Combined with high quality Microarray screening results and bioinformatics analyses, We focused that LncRNA SNHG15 and miR-451 are both downstream target of Notch-1, a possible combination and regulation may be exist, however the exact mechanisim was needed further study. Based on previous research acheivement, with genetic regulation, luciferase activity assay, RNA immunoprecipitation, site-specific mutation, RNA pull down assay and other technology of molecular biology, the aim of this study is to reveal the molecular mechanism of interactions between LncRNA SNHG15 and miR-451 participated in Notch-1 induced EGFR-TKI resistance in human lung adenocarcinoma, MDR-1 was directly retulated by miR-451 which might be play a significant role in the process. It will provide a novel target for reversing chemoresistance and clinical individualized treatment of lung adenocarcinoma.

化疗耐药形成是目前限制肺腺癌临床TKI靶向治疗的重要瓶颈，往往涉及表观遗传学及重要信号通路的调控异常，以及众多耐药关键基因的遗传改变。我们前期在人肺腺癌EGFR-TKI耐药细胞建立的基础上研究发现，Notch通路上重要受体Notch-1的异常激活可能参与了肺癌腺EGFR-TKI靶向治疗耐药表型的形成，高通量芯片筛选结合生物信息学分析结果提示，其下游LncRNA SNHG15与miR-451之间存在可能的结合调控关系。本课题拟在前期已取得的研究成果上，运用基因调控、荧光素酶活性实验、RNA免疫沉淀、位点突变、RNA pull down等分子生物学实验技术，从体内外结合临床标本探寻LncRNA SNHG15与miR-451之间的相互作用调控其下游靶基因MDR-1表达，最终参与调控Notch-1介导的肺腺癌EGFR-TKI化疗耐药形成的分子机制，为肺腺癌个体化治疗和逆转耐药提供新的靶点。

肺腺癌EGFR-TKI耐药表型的形成涉及肿瘤耐药相关蛋白基因的遗传学及表观遗传学分子调控机制改变，是目前限制肺腺癌临床疗效的重要难题。在成功建立人肺腺癌EGFR-TKI细胞模型的基础上，本研究重点探讨了SNHG15在肺腺癌中调控吉非替尼耐药表型的作用。此前NOTCH通路被证实与肺腺癌耐药相关。LncRNA芯片分析显示，在肺腺癌吉非替尼耐药细胞中SNHG15表达增高。功能研究表明，在吉非替尼耐药的肺腺癌细胞中，SNHG15和MDR-1高表达且miR-451低表达能够促进肿瘤生长。进一步研究发现SNHG15通过抑制miR-451促进MDR-1的表达。此外，SNHG15的升高可能与ZEB1有关。拯救实验证实，下游分子MDR-1和miR-451可以实现对SNHG15下调的功能逆转。因此SNHG15可通过调控miR-451/MDR-1信号轴改变肺腺癌细胞对吉非替尼的耐药，促进肺腺癌治疗的进展。本课题从体内外探讨LncRNA SNHG15与miR-451相互作用调控其下游靶基因MDR1表达，最终影响肺腺癌EGFR-TKI耐药形成的分子机制，为临床逆转肺腺癌耐药提供新的分子靶标。