circRNA_102747/miR-221-3p/PTEN轴向调控胰腺癌吉西他滨化疗敏感性的机制研究

Most pancreatic cancer (PC) patients are at advanced stage and unresectable when the diagnosis is confirmed, thus, chemotherapy is the main therapeutic option. Gemcitabine is the first-line chemotherapy drug for advanced PC, unfortunately, the obtained chemoresistance largely inder its treatment effect, relevant chemoresistance mechanisms need to be further elucidated. Recent studies show that circular RNAs (circRNAs) are essential regulators for mutiple biological processes and diseases including tumors, while its role in PC chemoresistance remains unknown. We previously identified a gemcitabine-resistance related circRNA_102747 in PC, and found that its downregulation led to chemoresistance and apoptosis resistance to gemcitabine in PC cells. According to bioinformatics analysis and our previous research results, we speculate that circRNA_102747 may regulate PC gemcitabine sensitivity through competitively binding miR-221-3p to post-transcriptionally regulate PTEN xpression. To verify the above hypothesis, we will explore the regulatory role and its molecular echanism of circRNA_102747 in PC gemcitabine sensitivity by molecular biology, cell assays, human tissue and animal assays using the plasmid transfection, RNA interference and luciferase reporter assay as the main research methods. This study is expected to provide a new theoretical basis and therapeutic targets for clinical reversal of PC chemoresistance.

胰腺癌患者确诊时多已处于晚期，化疗成为主要治疗手段。吉西他滨是进展期胰腺癌的一线化疗药物，但继发耐药往往导致治疗失败，相关耐药机制仍待进一步阐明。circRNA是近期发现的在多种生物学过程以及疾病中起重要调控作用的非编码RNA。我们前期鉴定出一个胰腺癌吉西他滨继发耐药相关的circRNA_102747，发现其表达下调可导致胰腺癌细胞对吉西他滨的化疗耐药和凋亡抵抗，具体分子机制不明。根据生物信息学分析及前期研究结果，我们推测该circRNA可能通过竞争性结合miR-221-3p调控PTEN表达继而调节胰腺癌吉西他滨化疗敏感性。为验证这一假想，本项目拟采用质粒转染、RNA干扰、荧光素酶报告实验等方法作为主要研究手段，从分子、细胞、组织以及动物水平探讨circRNA_102747对胰腺癌吉西他滨化疗敏感性的调控作用及其分子机制。本项目旨在为临床逆转胰腺癌化疗耐药提供新的理论论依据和治疗靶点。

胰腺癌(PC)是恶性程度极高，患者确诊时多已处于晚期，化疗成为主要治疗方法，但继发耐药常导致治疗失败。circRNA近来被发现在肿瘤发生发展中发挥重要作用，但目前与PC继发耐药之间的相关性研究甚少。本项目基于前期circRNA microarray筛选得到的PC吉西他滨继发耐药相关的circRNA_102747，进一步检测其在PC细胞系及PC组织的表达水平，发现circRNA_102747不仅在胰腺癌吉西他滨继发耐药细胞株中表达下调，在其他多种胰腺癌耐药细胞系中也普遍表达下调。circRNA_102747在胰腺癌组织中的表达水平与癌旁组织无统计学差异，但与癌组织病理分级和预后呈负相关。通过外源性过表达circRNA_102747可以通过细胞周期阻滞于S期并增强吉西他滨诱导的细胞凋亡，逆转吉西他滨继发耐药。体内动物实验也进一步显示恢复性表达circRNA_102747可增强吉西他滨对胰腺癌移植瘤的抗癌活性。机制上，circRNA_102747定位于细胞质，可通过竞争性结合miRNA-221-3p抑制后者对PTEN的降解，从而抑制PI3K/AKT信号通路，增加吉西他滨诱导的细胞凋亡而逆转耐药。通过本项目研究，进一步丰富了PC耐药的分子机制，为下一步开展基于circRNA_102747逆转PC耐药的研究提供实验依据。