NTRK3及ISG20L1基因与卵巢上皮癌紫杉醇铂类化疗耐药机制的研究

Epithelia ovarian cancer (EOC) is one of the most common malignancies in gynecologic cancers with the highest mortality. Chemoresistance is the main reason for the poor prognosis. Our previous study showed that the copy number changes of NTRK3、ISG20L1、GSTT1、STARD5 and FREM1 in the whole genome were associated with the sensitivity to paclitaxel/platinum in EOC. Among these genes, the changes of mRNA and protein of NTRK3 and ISG20L1 have also been indicated to be related to chemosensitivity. NTRK3, a neurotrophic receptor tyrosine kinase 3, can activate p53 after self-phosphorylation. ISG20L1 is a p53 family target gene. Transcription of ISG20L1 is regulated by all p53 family members. Increased expression level of ISG20L1 can induce cell autophagy. It was showed that increased expression of NTRK3 and ISG20L1 was related to the good prognosis of breast cancer. However, the relationship between both genes and chemoresistance in EOC is rarely studied. In the present research, we plan to further verify the relationship between chemosensitivity and the levels of mRNA and protein of two genes in EOC, which has been rarely reported so far. Then, we will discuss the mechanism of resistance to palcitaxel/platinum through NTRK3 and ISG20L1, which might be the important clues for overcoming the chemoresistance.

卵巢上皮癌是妇科恶性肿瘤中常见且病死率最高的恶性肿瘤，主要原因之一在于化疗耐药。我们的前期研究在全基因组范围内对紫杉醇铂类化疗后敏感与耐药肿瘤进行比较发现，NTRK3、ISG20L1、GSTT1、STARD5和FREM1基因的拷贝数变化与化疗敏感性明确相关。其中NTRK3和ISG20L1在mRNA和蛋白水平的变化与DNA拷贝数变化一致，亦显示出与紫杉醇铂类化疗效果有一定的相关性。NTRK3是神经营养受体酪氨酸激酶3，可导致p53的磷酸化。ISG20L1是p53的靶基因，其转录受p53家族的调节，当其蛋白表达水平增高时，细胞发生自吞噬而死亡。有研究显示，二者表达上调与乳腺癌等预后较好相关，但二者与卵巢癌化疗敏感性的探讨罕见报道。本课题拟在已有的基础上进一步验证上述两个基因mRNA和蛋白水平的变化与紫杉醇铂类化疗效果的相关性，并深入探讨NTRK3和ISG20L1与肿瘤化疗敏感性的机制。

卵巢上皮癌的病死率位居女性生殖系统恶性肿瘤之首，化疗耐药是卵巢癌治疗失败的主要原因。化疗耐药的研究一直是卵巢癌的研究热点。本课题首先验证NTRK3和ISG20L1两个基因mRNA和蛋白水平的变化与紫杉醇铂类化疗效果的相关性。发现NTRK3的mRNA水平变化与DNA一致，并与卵巢癌紫杉醇卡铂疗效相关。而ISG20L1的mRNA变化与DNA变化不一致，且其变化与卵巢癌紫杉醇卡铂化疗疗效无明显相关性。因此，我们深入探讨了NTRK3是否通过Akt/MAPK通路导致肿瘤发生耐药，为进一步探讨卵巢癌耐药机制及克服耐药的靶点提供依据。目前研究组在SKOV-3、Caov-3、OVCAR-3和Caov-4细胞系中提取总蛋白，通过western blot 的方法检测各细胞系中NTRK3基因编码蛋白的本底表达水平。将本底表达水平低者的NTRK3蛋白通过构建NTRK3全长转录本真核表达载体，正义转染低表达细胞系上调蛋白表达，用针对NTRK3基因的特异shRNA，转染本底表达水平高的细胞系。比较NTRK3不同表达水平的细胞系在紫杉醇/卡铂作用后存活情况。NTRK3蛋白变化是否通过Akt或ERK1/2磷酸化途径所导致的实验尚在进行之中，结果待分析。