A2M介导Fas信号传导途径提高卵巢癌对铂类化疗的敏感性研究

目的 探讨A2M基因的表达与卵巢癌患者耐药及预后的关系及其对Fas信号传导通路的影响。方法 利用癌症基因图集（The Cancer  Genome Atlas，TCGA）数据库中铂类敏感和耐药的卵巢癌患者的基因表达谱，分析A2M基因在铂类敏感和耐药患者中的表达差异。利用已构建的带有绿色荧光标记的卵巢癌SKOV3敏感细胞（SKOV3-GFP）和顺铂耐药细胞（SKOV3-GFP/DDPⅡ）进行裸鼠皮下种植，成瘤后分次予以顺铂体内干预，以实时荧光定量PCR（real-time quantitative PCR，qRT-PCR）技术检测不同次数顺铂干预后的肿瘤组织中A2M mRNA与Fas信号传导通路上重要节点基因的表达水平。用双变量线性回归分析A2M mRNA与所检测基因的表达量的相关性。结果 相对于铂类敏感病例，A2M mRNA在铂类耐药患者中的表达下降（P<0.05），A2M mRNA的表达与耐药相关（P=0.02），与卵巢癌患者总生存期、化疗间隔生存期和无疾病进展生存期高度相关（P均<0.001），其表达量越高，患者生存期越长。A2M mRNA以及细胞凋亡相关的Fas信号传导通路上重要节点基因Fas、FADD、caspase10、caspase9 和caspase3随顺铂注射次数的增加，在耐药的移植瘤组织中相对低表达（P<0.001）；而其下游与DNA修复相关的基因PARP1随顺铂注射次数的增加，在耐药的移植瘤组织中相对高表达（P<0.05）。A2M mRNA的表达与Fas信号传导通路上节点基因的表达存在线性相关（P<0.05）。结论 A2M可能是卵巢癌顺铂耐药的潜在信号分子，它可能维持肿瘤细胞对铂类药物的敏感性。其在耐药细胞中的低表达可能通过某种机制抑制下游的Fas信号传导通路，使其传导失调，最终引起PARP1的表达上调，促进DNA修复，抑制细胞凋亡，诱发卵巢癌细胞对顺铂的耐药。

Association between A2M-induced Fas apoptotic signaling and ovarian tumor sensitivity to platinum-based chemotherapy

Objective To analyze the relationship of A2M-induced Fas signaling to drug resistance of ovarian cancer and to patient prognosis. Methods We used gene expression profiles in the Cancer Genome Atlas to search for correlations of A2M expression with drug resistance of ovarian cancer and with patient prognosis based on Pearson correlation analysis. Cisplatin-sensitive or-resistant SKOV3 ovarian cancer cells expressing green fluorescent protein were inoculated subcutaneously into nude mice. At different times after cisplatin administration， tumor tissues were analyzed using real-time fluorescent quantitative PCR to determine expression of A2M and key node genes in the Fas pathway. Correlation between A2M expression and expression of node genes was examined using linear regression. Results A2M correlates significantly with drug resistance of ovarian cancer（P=0.020）. A2M was expressed at significantly lower levels in platinum-resistant tissue than in platinum-sensitive tissue（P<0.05），and higher A2M levels correlated significantly with longer platinum-free interval，overall survival，and progression-free survival（P<0.001）. Platinum-resistant trans-planted tumors expressed significantly lower levels of A2M and the apoptosis-related node genes Fas，FADD，Caspase10， Cas-pase9 and Caspase3 than did platinum-sensitive tumors（P<0.001）. The downstream gene PARP1，important for DNA repair，was expressed at a significantly higher level in platinum-resistant tumors（P< 0.05）. Expression of A2M correlated linearly with that of node genes of the Fas signaling pathway（P<0.05）. Conclusions A2M may be a marker of cisplatin resistance in ovarian cancer. Lower levels of A2M expression may up-regulate expression of the DNA repair protein PARP1， inhibiting cell apoptosis and ultimately leading to cisplatin resistance.