Hsa-circ-PLK1-antisense.1/miR-593-5p/PLK1途径对胃癌细胞耐药性的影响及作用机制的研究

The emergence of drug resistance is the main cause of the failure of chemotherapy in advanced gastric cancer. Looking for the key nodes involved in chemoresistance pathway and targeted intervention at these nodes are important research directions of preventing or reversing chemoresistance. Our previous study has shown that high expression of PLK1 could promote the chemoresistance of gastric cancer cells. Moreover, the highly selective and potent PLK1 inhibitor BI2536 and cisplatin could synergistically inhibit the malignant behavior of SGC-7901/DDP gastric cancer cells. Thereby, BI2536 could promote the chemosensitivity of cisplatin in gastric cancer cells. However, the key mechanism of PLK1 on regulating the chemoresistance of gastric cancer cells is largely unknown. In this study, the results of bioinformatics analysis predicted that hsa-circ-PLK1-antisense.1 could function as a ceRNA to regulate the expression of PLK1 through sponging miR-593-5p. Our preliminary experiments also confirmed that hsa-circ-PLK1-antisense.1 and miR-593-5p could be involved in the regulation of PLK1 expression. Meanwhile, previous findings have revealed that activation of Wnt pathway played a key role in regulating the chemoresistance of gastric cancer. We thus hypothesized that hsa-circ-PLK1-antisense.1 could bind to miR-593-5p to regulate the expression of PLK1 and then affected the chemoresistance of gastric cancer via activation of Wnt pathway. To verify this hypothesis, this study firstly determined whether hsa-circ-PLK1-antisense.1, miR-593-5p and PLK1 were dysregulated in clinical gastric cancer tissues. Then the regulatory relationship between hsa-circ-PLK1-antisense.1, miR-593-5p, and PLK1 at cellular levels was explored in vitro, as well as their effects on the chemoresistance of gastric cancer. Besides, a nude mouse model of subcutaneously implanted tumor was established to further explore the pathway of hsa-circ-PLK1-antisense.1/miR-593-5p/PLK1 in the occurrence of chemoresistance of gastric cancer in vivo. The findings of this study may provide a new insight for the treatment of gastric cancer.

耐药的发生是导致进展期胃癌化疗失败的主要因素,寻找耐药通路发生的重要节点并进行靶向干预是抑制耐药的重要研究方向。我们前期研究发现,PLK1高表达同胃癌耐药性相关;调控PLK1可影响胃癌细胞对顺铂的化疗敏感性。但PLK1在胃癌耐药性中的作用机制尚未阐明。生物信息学预测及预实验,我们发现hsa-circ-PLK1-antisense.1和miR-593-5p均可调节PLK1表达。由此推测circ-PLK1-antisense.1作为ceRNA竞争性参与miR-593-5p对PLK1的调控,进而激活Wnt通路影响胃癌耐药性的产生。为此,我们拟在临床水平确认三者在胃癌耐药组织中的异常表达,细胞水平探讨hsa-circ-PLK1-antisense.1/miR-593-5p/PLK1通路之间的调控关系以及对耐药性的作用。最后,动物模型验证该通路对胃癌耐药性发生的机制。本研究旨在为胃癌治疗提供新靶点。

耐药的发生是导致进展期胃癌化疗失败的主要因素,寻找耐药通路发生的重要节点并进行靶向干预是抑制耐药的重要研究方向。本课题组前期研究发现,在胃癌耐药组织及体外耐药细胞中PLK1 高表达;调控PLK1 可影响胃癌细胞对顺铂的化疗敏感性。但PLK1 在胃癌耐药性中的作用机制还未阐明。通过生物信息学预测及预实验,我们发现hsa-circ-PLK1-antisense.1 和miR-593-5p 作为上游靶点均可调节PLK1 的表达。因此推测,hsa-circ-PLK1-antisense.1 作为ceRNA竞争性参与miR-593-5p 对PLK1 的调控,进而激活Wnt 通路影响胃癌耐药性的产生。为此,本研究提出假说“Circ-PLK1-antisense.1 作为ceRNA 竞争性抑制miR-593-5p 对PLK1 的抑制作用，调控PLK1 表达水平和Wnt 通路，进而影响胃癌耐药”,在临床水平确认三者在胃癌耐药组织中异常表达,在细胞及分子水平探讨该通路之间的调控关系以及在耐药性产生中的作用。最后,通过动物成瘤模型来观察这些分子异常表达在体内的作用机制。本研究的成果旨在为胃癌治疗提供新靶点，具有明确的科学意义和潜在临床价值。