长链非编码RNA AK308467调控三阴乳腺癌化疗耐药的作用及机制研究

There is a higher incidence of chemotherapeutic drug resistance in thetriple-negative breast cancer(TNBC) which has a poor prognosis due to lack of effective treatments. Triple-negative breast cancer(TNBC) is still a clinical challenge. AK308467 was specially up-regulated in the drug resistance TNBC, identified from differential lncRNA expression profile between chemotherapeutic drug resistance TNBC tissue and drug sensitive TNBC tissue. Previous study showed that up-regulated expression of AK308467 in MDA-MB-231 cells could promote the development of chemotherapeutic drug resistance with markedly high expressed ABCB1. On the other hand, bioinformatics analysis and previous experiment data indicated that ABCB1 could be a candidate target gene of AK308467. This study will confirm the function of AK308467, using overexpression and knock down strategies in MDA-MB-231 and MDA-MB-231/ADR cells, by analyzing the cell behavior and molecular characteristics; subsequently using RIP and RNA pull down to clarify the underlying mechanism of chemotherapeutic drug resistance between AK308467 and ABCB1 in TNBC. We will also use nude mice to evaluate the effect of AK308467 on chemotherapeutic drug resistance and expression of ABCB1 in TNBC. Up to now, there was no report about the function and mechanism of lncRNAs in the process of chemotherapeutic drug resistance in TNBC. The innovative proposal by this study could possibly find a new target to avoid chemotherapeutic drug resistance in TNBC.

三阴乳腺癌化疗耐药发生率高，缺乏有效治疗手段，预后极差，是乳腺癌临床治疗的重大难题。AK308467是我们采用芯片发现的、高表达于化疗耐药三阴乳腺癌组织中、功能未知的lncRNA。前期发现，过表达AK308467使三阴乳腺癌细胞MDA-MB-231耐药性增强；生物信息学及预实验初步确定ABCB1为AK308467靶标。文献报道ABCB1与三阴乳腺癌化疗耐药密切相关，提示AK308467可能通过调控ABCB1参与三阴乳腺癌化疗耐药。本研究拟采用过表达、沉默策略，明确AK308467在三阴乳腺癌耐药中的功能；并以ABCB1为机制线索，利用RIP、RNA pull down实验揭示AK308467调控三阴乳腺癌细胞耐药的分子机制；借助裸鼠模型，在体观察AK308467与三阴乳腺癌耐药的关系。本研究具有源头创新性，将有助于理解三阴乳腺癌耐药的分子机制，为临床三阴乳腺癌化疗耐药提供潜在的干预靶标。

三阴乳腺癌化疗耐药发生率高，缺乏有效治疗手段，预后极差，是乳腺癌临床治疗的重大难题。在本项目中，我们首先构建了三阴乳腺癌细胞株MDA-MB-231耐阿霉素细胞模型，在此基础上，采用高通量测序筛选发现Linc0056020是高表达于阿霉素化疗耐药三阴乳腺癌细胞中、功能未知的lncRNA。进一步研究发现过表达Linc0056020使三阴乳腺癌细胞MDA-MB-231耐阿霉素增强；反之，干涉Linc0056020表达使耐药细胞株侵袭性等有所下降；通过信息学分析，结合蛋白质谱检测，证实β1整合素（β1-integrin）为Linc0056020靶标：耐阿霉素MDA-MB-231细胞株中β1-integrin的表达增加，过表达和干涉Linc0056020导致β1-integrin的蛋白表达水平发生改变。由此，揭示了Linc0056020通过调控β1-integrin参与三阴乳腺癌阿霉素化疗耐药。上述研究为临床三阴乳腺癌化疗耐药提供潜在的干预靶标。