circRNA_0027497通过ceRNA机制调控自噬效应影响胃癌5-FU耐药的机制研究

5-fluorouracil (5-FU) is the first-line drug for the chemotherapy of advanced gastric cancer, and circular RNA (circRNA) may influence the chemosensitivity by regulating autophagy. By using the microarray or sequencing technologies to detect the 5-FU resistant/sensitive gastric cancer cell lines, we have identified the ceRNA axis of circ0027497-miR-21-3p-PRKAA2, which related to 5-FU drug resistance and autophagy regulation pathway, and the genetic variant associated with the expression of circ0027497. The aim of this project is to determine the effect of genetic variant- regulated circ0027497 on 5-FU sensitivity by upregulating autophagy-related gene PRAKK2 via sponging miR-21-3p and explore the following molecular mechanisms by using a series of molecular cell experiments in 5-FU resistant/sensitive gastric cancer cell lines, human gastric organoids, orthotropic tumor models and patients’ samples. This study is very helpful for the better understanding of 5-FU resistance, and will provide a new theoretical basis for designing individualized treatment, assessing curative effect of gastric cancer and reversing 5-FU drug resistance.

5-氟尿嘧啶（5-FU）是进展期胃癌的一线化疗药物，环状 RNA可能通过改变细胞自噬水平影响药物的敏感性。本课题组前期利用芯片及二代测序技术检测5-FU耐药/敏感胃癌细胞，通过聚类分析、细胞及组织样本验证等，筛选出与5-FU耐药及自噬相关的circ0027497-miR-21-3p-PRKAA2作用轴及可能调控circ0027497表达的遗传变异。本项目拟通过细胞、类器官模型、小鼠原位瘤模型以及胃癌化疗人群样本，运用一系列分子细胞实验明确受遗传变异影响的circ0027497可通过靶向吸附miR-21-3p上调自噬相关蛋白PRKAA2影响5-FU药物敏感性的内在机制。本研究将有助于进一步阐明胃癌5-FU耐药的发生机制，为胃癌的个体化治疗、疗效评估及逆转耐药等提供新的理论依据。

5-氟尿嘧啶（5-FU）是晚期胃癌（GC）化疗的一线药物。然而，其疗效因化疗耐药而显着减弱，并与患者预后差有关。最近，有证据表明，自噬失调可能有助于癌症的耐药，而环状RNA（circRNA）也参与化疗耐药。结合RNA测序技术和生物信息学分析，我们首先构建了影响5-FU耐药和自噬的ceRNA调控网络。通过在细胞系和组织中的进一步验证，我们最终确定了调节GC自噬和5-FU耐药的circ0027497-miR-21-3p-PRKAA2轴。circ0027497在5-FU耐药GC细胞系和组织中上调，敲低circ0027497大大提高化疗敏感性。circ0027497直接与细胞质中的miR-21-3p结合，从而增加PRKAA2的表达，最终有助于激活自噬和促进耐药。此外，高circ0027497表达与低生存率呈正相关。我们的结果表明，circ0027497通过靶向PRKAA2在调节GC自噬和5-FU耐药中起着至关重要的作用。本项研究可为设计个体化治疗、评价GC疗效、逆转5-FU耐药提供新的理论依据。