Dicer 调节自噬促进上皮性卵巢癌顺铂耐药的分子机制研究

Chemotherapy drug resistance is the critical factor for tumor death and recurrence, especially in ovarian cancer. In previous studies, we found that low expression of Dicer was associated with chemotherapy drug resistance in ovarian cancer. Down-regulation of Dicer could induce autophagy, inhibition of autophagy potentiates cell sensitivity to cisplatin treatment.Through database prediction, we found that RNA binding protein hnRNPC was negatively correlated with Dicer.In our preliminary experiments, HNRNNPC has been confirmed to reduce the expression of Dicer. Therefore, we speculate that hnRNPC can downregulate Dicer through post-transcriptional regulation, reduce the inhibitory effect of target gene ATG5 by affecting the specific miRNA production, and enhance autophagy in cisplatin-resistant ovarian tumors. This study predicted, by using bioinformatics, RIP experiment, Dual Luciferase Reporter Assay and drug resistance related experiments; the expression of Dicer and chemotherapy drug resistance of ovarian tumors correlation; the effect of hnRNPC/Dicer1 axis and miRNA in the regulation of autophagy; and the gradual development of chemoresistance mechanism in ovarian tumors. This study clarified the molecular mechanism of hnRNPC downregulating Dicer1 and inducing autophagy in chemotherapy resistant ovarian cancer, and provided more theoretical basis for the improved treatment of chemoresistant ovarian cancer.

化疗耐药是肿瘤复发致死的关键因素，在卵巢癌中尤为明显。前期研究中，我们发现Dicer低表达与卵巢癌化疗耐药相关，且发现下调Dicer能诱导自噬，自噬抑制剂联合顺铂能明显增强顺铂对上皮性卵巢癌杀伤效应，并逆转化疗耐药。通过数据库预测RNA结合蛋白hnRNPC与Dicer负相关，在前期预实验中已证实hnRNPC能降低Dicer表达。因此我们推测，hnRNPC下调Dicer，通过调控特定miRNA引起自噬相关基因表达，提高卵巢癌自噬水平导致卵巢癌化疗耐药。本研究将通过生物信息学预测，RIP实验，双荧光素酶报告实验及耐药相关实验等，对Dicer表达与卵巢癌化疗耐药相关性，hnRNPC/Dicer/miR轴在调节自噬引起卵巢癌化疗耐药的内在作用机理等进行逐步验证。本研究通过阐明hnRNPC下调Dicer诱导自噬引起卵巢癌化疗耐药的分子机制，为改善卵巢癌化疗耐药的治疗效果提供更多理论依据。

上皮性卵巢癌的共同特点是容易复发，复发后对化疗药物的敏感性差。因此，探索这种现象的机制，克服这种不敏感性是卵巢癌治疗的重要目标。首先，我们发现Dicer在卵巢癌组织中的表达明显低于正常组织，而这种低表达往往伴随着化疗药物对肿瘤细胞杀伤作用的减弱。从机制上讲，我们发现在 Dicer 被下调后，细胞中的自噬反应被激活。在这个过程中，Dicer/miR-93/Atg5 轴发挥了重要作用。此外，我们通过数据库和临床标本分析发现，作为RBP的重要成员之一的hnRNPC在卵巢癌中与Dicer呈显着正相关。细胞实验表明，hnRNPC可以通过转录后调控影响Dicer的表达水平，从而调节Dicer对自噬和卵巢癌化疗敏感性的影响。该结论为卵巢癌靶向治疗的应用提供了理论依据，也为相关靶点在临床转化医学中的应用奠定了理论基础。