长链非编码RNA MEG3作为ceRNA调控miR-27a在膀胱癌侵袭转移中的作用机制研究

Metastasis is the most important lethal reason of bladder cancer. And controlling the invasive and metastasis ability tends to be the key point for treating bladder cancer. Recent studies demonstrate the lncRNA MEG3 is impactful in regulating multiple biological behaves of a variety of cancer cells, however nothing was dressed out if MEG3 could regulate the invasive ability of bladder cancer cells. Our pre-experiment confirmed that MEG3 was obviously downregulated in bladder cancer tissues, and exogenous overexpression MEG3 could also efficiently inhibit the invasive ability of bladder cancer cell without affecting the migration ability. At the same time, miR-27a was found significantly up-regulated in bladder cancer tissues, and exogenous overexpression miR-27a to simulate the bladder cancer showed a considerable increase of invasive ability. What is more interesting is that the effect of MEG3 could be blocked by exogenous overexpression of miR-27a. Also, the bioinformatics analysis shows that MEG3 might regulate the function of miR-27a as a competing endogenous RNA (ceRNA). On these basis, this project tries to systemically reveal the molecular mechanism underlying the regulation of miR-27a by MEG3 as a ceRNA, and the function and detail mechanism in regulating metastasis and invasion of bladder cancer. This work will reveal the function of MEG3 and miR-27a in regulating the bladder cancer invasive ability for the first time, and led to a novel insight both on further basic research and therapy of bladder carcinoma.

膀胱癌远处转移是其致死重要原因，控制癌细胞的侵袭浸润能力是治疗膀胱癌的关键所在。近期研究表明lncRNA MEG3在多种肿瘤细胞生物学行为的调控中均发挥重要作用，但其对膀胱癌细胞侵袭能力的影响目前尚不清楚。申请者前期实验结果显示，MEG3在膀胱癌中表达显著下调，而过表达MEG3能有效抑制膀胱癌细胞的侵袭能力；另一方面miR-27a在膀胱癌中表达显著上调，模拟膀胱癌过表达miR-27a能有效促进细胞的侵袭能力，并能有效抑制MEG3对膀胱癌侵袭能力的下调。生物信息学分析显示MEG3能作为竞争性内源性RNA（ceRNA）调控miR-27a的功能。本课题拟在大量前期工作的基础上，系统解析MEG3作为ceRNA调控miR-27a，及其在调控膀胱癌侵袭浸润中的作用及分子机制。该项目的成功实施，有望首次揭示MEG3和miR-27a对膀胱癌侵袭能力调控的机理，为膀胱癌的进一步研究和治疗开启新的思路。

膀胱癌远处转移是其致死重要原因，控制癌细胞的侵袭浸润能力是治疗膀胱癌的关键所在。本研究表明MEG3能显著抑制膀胱癌细胞的侵袭能力。研究结果显示，MEG3在肌层浸润性膀胱癌中相较非肌层浸润性膀胱癌表达显著下调，而过表达MEG3能有效抑制膀胱癌细胞的侵袭能力。MEG3可以以ceRNA的形式有效募集miR-27a，进而解除miR-27a对PHLPP2 3UTR活性的抑制，促进其翻译。该过程加速了c-Jun在Ser63和Ser73位点的磷酸水解过程，下调了其磷酸化水平，进而抑制了c-Myc启动子活性，影响c-Myc转录，导致c-Myc低水平的表达状态，进而下调了膀胱癌细胞的侵袭能力。动物水平实验进一步证实了MEG3对膀胱肿瘤细胞侵袭能力的抑制。本课题系统解析了MEG3作为ceRNA调控miR-27a/PHLPP2，及其在膀胱癌侵袭浸润调控中的作用及分子机制。该项目的成功实施，可能为膀胱癌的进一步研究和治疗开启新的思路。