linc00657通过HILI-piRNA途径调控胶质瘤血肿瘤屏障通透性的分子机制

The blood-tumor barrier (BTB) restricts the efficacy of chemotherapy against gliomas by confining drug delivery to tumor tissue. Our previous research found that HILI, the protein expressed in glioma endothelial cells (GECs), was able to affect the permeability of BTB. However, the mechanism of HILI’s functions remains unclear. Based on our previous work, we propose the following hypotheses. Firstly, HILI bonds with linc00657 and up-regulates its expression by interacting with DQ59074. In addition, Linc00657 weakens the effect between miR-205 and NFIB/NFIX. Furthermore, NFIB and NFIX are involved in changing the permeability of BTB via positively regulating the expression. To prove the presumption, in this project, we focus on these inferences of interest: i) whether HILI reflects the BTB permeability by inhibiting the expression of linc00657; ii) whether linc00657 regulates the BTB permeability via the reduced expression of miR-205; iii) whether miR-205 reflects the BTB permeability by decreasing the NFIB and NFIX; iv) the optimum solution to enhance the BTB permeability with the help of single, or combined, inhibitors which aim to multiple targets including HILI, piRNA(DQ590704), linc00657 and miR-205; v) how the combination of the optimum solution with adriamycin would exerte tumor -suppressive functions in nude mice with gliomas. The potential impacts of this project may include, not only knowing how the HILI reflects the BTB permeability, but also providing an interesting drug target for the modulation of the BTB to enhance penetration of drugs into the brain and thus to widen therapeutic options for gliomas.

血肿瘤屏障(BTB)是影响胶质瘤化疗效果的关键。前期研究发现脑胶质瘤微血管内皮细胞中HILI影响BTB的通透性。我们通过系列前期工作建立了工作假说：胶质瘤微血管内皮细胞中低表达的HILI通过DQ590704靶向结合linc00657，并使之高表达。linc00657能够结合并负性调控miR-205对NFIB和NFIX的作用， NFIB和NFIX能够正性调控claudin-5、occludin和ZO-1的表达，改变BTB通透性。本研究先验证HILI-piRNA途径是否通过抑制linc00657影响BTB通透性；其次研究linc00657是否通过抑制miR-205调节BTB通透性；同时研究miR-205是否通过NFIB和NFIX调控BTB通透性；最后确定HILI、piRNA(DQ590704)、linc00657与miR-205多个靶点的抑制剂或激动剂单独或联合应用增加BTB通透性的最佳方式。

血肿瘤屏障(BTB)是阻碍胶质瘤化疗药物到达肿瘤组织发挥治疗效果的关键。前期研究发现脑胶质瘤微血管内皮细胞中HILI的表达变化影响BTB的通透性，同时发现 HILI-piRNA 途径可降低 linc00657在脑胶质瘤微血管内皮细胞中的表达。在前期研究结果基础上，为明确HILI-piRNA 途径对BTB通透性的调节效果和机制，我们通过双荧光素酶报告基因系统分析、体外血肿瘤屏障模型制备、跨内皮电阻测定、载体构建等技术研究发现：linc00657 分别存在 piRNA (DQ590704)和miR-205 的结合位点；低表达的 HILI通过 piRNA (DQ590704)靶向结合 linc00657，并使之高表达；linc00657 能够结合并负性调控 miR-205 对转录因子NFIB 和 NFIX 的作用；NFIB 和 NFIX 能够在转录水平增加紧密连接相关蛋白 claudin-5、occludin、 ZO-1 的表达，改变血肿瘤屏障通透性。此研究结果表明通过HILI-piRNA 途径可以增加血肿瘤屏障通透性，为增加化疗药物转运进入肿瘤组织，切实提高疗效提供新靶点。本研究的结果不仅为非编码RNA的临床应用提供理论依据，而且能为脑胶质瘤的治疗提供新途径，为脑胶质瘤靶向药物研发提供新靶点。