肿瘤诊断后十字花科蔬菜摄入与卵巢癌顺铂化疗敏感性的关系及其机制研究

Platinum-based chemotherapy resistant has become one of the tough questions in the treatment of ovarian cancer. Recent evidence demonstrated that the expression of excision repair cross-complementation group 1 (ERCC1) and breast cancer susceptibility gene 1 (BRCA1) was inversely associated with the response to cisplatin-based chemotherapy. Our previous findings have provided evidence that high cruciferous vegetable intake may reduce the risk of certain cancers (e.g., lung cancer, colorectal cancer, and gastric cancer) and improve the survival of female lung cancer. Sulforaphane (SFN) as well as indole-3-carbinol (I3C), the major hydrolysis products and bioactive compounds of cruciferous vegetables, are involved in the inhibition of cancer growth and proliferation as well as the induction of apoptosis. Based on these findings and hypothesis, firstly, we are proposed to investigate whether SFN and I3C of cruciferous vegetables may enhance the sensitivity of human ovarian cancer cell to cisplatin through regulating the expression of ERCC1 and BRCA1 by in vitro experiments. Meanwhile, we will carry out a prospective cohort study including surgery confirmed incident cases of ovarian cancer with cisplatin-based chemotherapy identified from the Shengjing Hospital of China Medical University. On the basis of this cohort, we will investigate the associations between post-diagnostic cruciferous vegetables intake and the metabolite of cruciferous vegetables in the urinary and the response to cisplatin-based chemotherapy. Taken together, the findings of this project will not only contribute to understanding the potential mechanisms of beneficial effect of cruciferous vegetables on the response to cisplatin-based chemotherapy of ovarian cancer but also provide evidence and support the development of post-diagnostic dietary suggestions for these patients, which has important clinical implications for enhancing the sensitivity of cisplatin-based chemotherapy and improving the survival of ovarian cancer patients.

卵巢癌对铂类耐药已经成为其治疗中的难题。切除修复交叉互补基因1（ERCC1）和乳腺癌易感基因1（BRCA1）的表达水平与顺铂化疗敏感性呈负相关。本项目前期研究发现多摄入十字花科蔬菜能够预防多个恶性肿瘤的发生并改善其预后。吲哚-3-甲醇（I3C）和异硫氰酸酯中的莱菔烷胺（SFN）作为其主要生物活性成分，能够抑制肿瘤细胞生长和分化并诱导其凋亡。本研究拟先通过体外实验研究SFN和I3C能否通过调控ERCC1和/或BRCA1的表达，增强卵巢癌细胞对顺铂敏感性的作用机制；同时通过前瞻性研究，调查经手术确诊并接受顺铂为基础化疗的卵巢癌患者，研究其肿瘤诊断后十字花科蔬菜摄入及其尿液中代谢产物与顺铂化疗应答之间的关系。本项目将体外实验和流行病学研究有机地结合，研究结果不仅能够明确十字花科蔬菜增强卵巢癌顺铂化疗敏感性的作用机制，而且为制定卵巢癌患者诊断后的膳食指导意见奠定研究基础，对改善其预后具有重要意义。

本课题首次通过实验研究和流行病学研究相结合的方式探讨肿瘤诊断后十字花科蔬菜摄入与卵巢癌顺铂化疗敏感性的关系及其机制研究。在实验研究方面，课题首先通过体外实验，研究了十字花科蔬菜中的生物活性成分吲哚-3-甲醇（I3C）和莱菔烷胺（SFN）在逆转耐药卵巢癌细胞对顺铂耐药性中的作用。研究发现，I3C通过诱导细胞周期G0/G1期阻滞和增加顺铂向细胞内转运的方式逆转了顺铂耐药卵巢癌细胞对顺铂的耐药性。I3C降低在耐药卵巢癌细胞中高表达的miR-21的表达，荧光素酶报告基因实验证实miR-21能够靶向调节细胞周期关键蛋白P18和顺铂细胞内外转运关键蛋白CTR1的表达。以上说明I3C可通过miR-21-P18/CTR1途径调节卵巢癌细胞周期变化并促进顺铂向细胞内转运，从而提高顺铂耐药卵巢癌细胞对顺铂的敏感性。同时，本课题还发现SFN可上调顺铂耐药卵巢癌细胞中低表达的miR-30a-3p的表达水平，荧光素酶报告基因实验证实miR-30a-3p可以靶向调控DNA修复关键蛋白ERCC1和细胞内外顺铂转运关键蛋白ATP7A的表达。即SFN可经miR-30a-3p-ERCC1/ATP7A途径调节顺铂耐药卵巢癌细胞中DNA损伤修复以及细胞内外顺铂的转运，有效缓解了顺铂耐药卵巢癌细胞对顺铂的耐药性；在流行病学研究方面，课题建立了盛京医院卵巢癌单病种双向性队列，选择2017-2019间年入组前瞻性队列的317例卵巢癌进行随访，经过中位1.7年的随访（范围：0.4-2.9年），发生63例卵巢癌顺铂耐药。通过Cox回归分析并调整相应的混杂因素，发现卵巢癌诊断后十字花科蔬菜摄入与顺铂化疗耐药呈负相关（HR=0.88, 95%CI: 0.72-1.07，P for trend=0.08）。本课题未来将对卵巢癌患者进行更长期的随访，以期能够更好的观察到两者之间的关联。上述研究结果将为制定卵巢癌患者诊断后的膳食指导意见奠定研究基础，对改善其预后具有重要意义。