卵泡刺激素受体介导的靶向阻遏糖酵解途径对卵巢癌的化疗增敏及其机制

Ovarian cancer is the leading cause of gynecologic malignancies. Most patients are diagnosed at advanced stages and have only a 30% five-year survival rate. Those patients at advanced disease stage will often recur and develop chemoresistance. The metabolic changes in distinct disease stages have been studied using ovarian surface epithelial cancer progression model. The cell metabolism is shifted to a more glycolytic phenotype as ovarian cancer progresses. The dependency on aerobic glycolysis of cancer cells is necessary to sustain their growth and proliferation. Moreover, the drug-induced apoptosis is decreased because of the increased energy production and metabolite synthesis. The shifting in metabolic pathways is linked to therapeutic resistance. Therefore, the alteration of cancer metabolism could be an effective strategy for cancer treatment. It is worth to study how selectively blocking the glycolytic pathway in ovarian cancer cells but not other normal cells. The ovary is the main target organ of follicle-stimulating hormone (FSH), which binds to its receptor with high affinity. The expression of FSH receptor (FSHR) is limited in the reproductive system and has also been found in ovarian cancer. Our previous work has shown that the drugs are selectively delivered into ovarian cancer cells because of the modification with FSH peptides on the surface of drug carriers. This project will develop FSH peptide-modified nanoparticle loading siRNA of glycolytic key enzymes to specific silence their expression in ovarian cancer by active and passive targeting. The decreasing of glycolysis will promote drug-induced apoptosis of ovarian cancer cells. Thus, the targeted nanoparticle complex of suppressing glycolysis could enhance therapeutic efficacy and overcome chemoresistance of ovarian cancer. Additionally, the impacts and mechanisms of silencing glycolytic key enzymes on malignant biological behaviors and chemoresistance of ovarian cancer will be studied in vitro and in vivo. This study will provide clues for the research on abnormal energy metabolism and chemo-sensitization in ovarian cancer, and will lay the foundation for the clinical application of targeted therapy.

晚期卵巢癌患者在治疗后大多复发或耐药使治疗失败，死亡率居高不下。研究表明随卵巢表面上皮细胞向恶性的逐步转化，细胞代谢逐渐向糖酵解方式转变。癌细胞对能量代谢的这种重编程保证了其快速增殖和抵抗杀伤所需能量和物质，如能对其进行转变有可能改善疗效。如何选择性在卵巢癌病灶阻断糖酵解途径，使癌细胞能量代谢向正常方式转变，从而阻止细胞对药物的抵抗，值得深入探索。我们前期工作表明，在载体上修饰以可与卵巢癌细胞表面卵泡刺激素受体结合的配体有助于提高药物靶向分布。本项目拟构建卵泡刺激素受体介导的靶向卵巢癌糖酵解关键酶的复合治疗系统，通过主动和被动靶向，有效沉默其在卵巢癌的表达，使癌细胞不能获取足够支持，难以对化疗药产生适应性保护而被杀灭；并研究卵巢癌能量代谢方式转变后，细胞恶性生物学行为和化疗耐药性的改变及机制。本研究对阐明卵巢癌异常能量代谢有重要意义，并为靶向治疗临床应用奠定基础，为化疗增敏研究提供新思路。

卵巢癌在临床确诊时多数已为晚期，这些患者在治疗后大多复发并对化疗反应性差而使治疗失败。能量代谢重编程在肿瘤进展和耐药中发挥重要作用，如能对其进行转变有可能改善预后。本项目研究了糖酵解途径关键酶在卵巢癌进展和耐药中的作用及机制，探讨其用于治疗的价值；构建了不同构型卵泡刺激素多肽修饰的糖酵解关键酶小干扰RNA纳米复合物，考察了其对能量代谢的影响、抗肿瘤疗效和化疗增敏效果。结果表明，己糖激酶2（hexokinase 2，HK2)、丙酮酸脱氢酶激酶1（pyruvate dehydrogenase kinase 1，PDK1）和PDK2在耐药卵巢癌中高表达。HK2促进顺铂诱导的自噬来参与耐药，PDK1和PDK2则参与耐药卵巢癌的侵袭迁移。更重要的是，高表达的糖酵解途径关键酶通过维持能量和物质供给参与卵巢癌进程和耐药。沉默HK2或PDK2均可导致卵巢癌能量代谢由糖酵解向线粒体氧化磷酸化转变，由此带来的能量和物质供给变化可抑制卵巢癌生长和其对顺铂杀伤的抵抗。具体表现为，沉默HK2、PDK1或PDK2后，敏感和耐药细胞的增殖和侵袭被抑制，凋亡增加；顺铂泵出蛋白ATP7B表达降低，凋亡相关蛋白表达增加，耐药细胞对顺铂的敏感性增强。我们前期工作表明，在载体上修饰以可与卵巢癌细胞表面卵泡刺激素受体结合的配体有助于提高药物靶向分布。因此，本项目构建了不同构型卵泡刺激素多肽修饰的糖酵解关键酶小干扰RNA纳米复合物。L或D构型多肽修饰的复合物均可抑制瘤体生长，增强顺铂对耐药卵巢癌的疗效，且毒副作用较低。此外，我们尝试在递药系统中引入第二重靶向来降低非特异性摄取。由于癌抗原125的编码基因黏蛋白抗原16高表达于卵巢癌，我们在卵泡刺激素受配体介导的靶向基础上，引入黏蛋白抗原16启动子作为第二重靶向调控，获得双靶向的纳米复合物，并初步探讨了其药物递送能力。综上所述，本项目研究了糖酵解途径关键酶对卵巢癌进程和耐药的促进作用，利用卵泡刺激素修饰的靶向递药系统揭示了其在卵巢癌治疗中的应用价值。研究结果有助于阐明卵巢癌的异常能量代谢，并为克服卵巢癌耐药提供研究线索。