内源性IL-8诱导卵巢癌细胞对顺铂与紫杉醇产生耐药的机制研究

The mechanism of cisplatin and paclitaxel resistance caused by endogenous IL-8 in ovarian cancer cells

目的探讨内源性IL-8诱导卵巢癌细胞对顺铂和紫杉醇产生耐药的机制及相关信号转导通路。方法在原有工作基础上,以2种人卵巢癌细胞系A2780(不分泌IL-8,对顺铂、紫杉醇敏感)和SKOV-3(高分泌IL-8,对顺铂、紫杉醇耐药)为研究模型,分别将正义(sense,ss)IL-8基因或反义(antisense,as)IL-8基因稳定转染至A2780细胞或SKOV3细胞,应用MTT法、Caspase-3活性测定、RT-PCR及Western blot技术等观察内源性IL-8是否影响卵巢癌细胞对顺铂和紫杉醇的敏感性,并对其作用的机制和可能的信号传导通路进行研究。结果 1)内源性过表达IL-8可诱导A2780细胞对顺铂和紫杉醇产生耐药,而抑制IL-8表达可恢复SKOV3细胞对顺铂和紫杉醇的敏感性,IL-8诱导的卵巢癌细胞化疗耐药是通过降低Caspase-3活性来实现的;2)内源性过表达IL-8可上调A2780细胞的耐药相关基因MDR1和凋亡抑制基因Bcl-2、Bcl-xL及XIAP的表达,而抑制IL-8表达可使上述基因的表达明显降低;3)Wortmannin(PI3K抑制剂)和PD98059(MEK1/2抑制剂)能分别阻断IL-8诱导下卵巢癌细胞的Akt和ERK活化及化疗耐药作用。结论 IL-8诱导的卵巢癌细胞化疗耐药可能与其上调耐药相关基因MDR1和凋亡抑制基因Bcl-2、Bcl-xL及XIAP的表达以及活化Raf/MEK/ERK和PI3K/Akt信号通路相关,提示调节IL-8表达或其相关信号通路可能是治疗耐药性卵巢癌的一种良好策略。

This study aimed to discover the mechanism of cisplatin and paclitaxel resistance caused by endogenous interleukin-8 （IL-8） in ovarian cancer cells and its related signal pathways. Based on our previous studies, A2780 （non-IL-8-expressing and cisplatin/paclitaxel-responsive） and SKOV-3 （IL-8-overexpressing and cisplatin/paclitaxel-resistant） cell lines were suitable models for this study. Then sense IL-8 or antisense IL-8 was stably transfected into A2780 and SKOV3 cells for detecting the effect of endogenous IL-8 on ovarian cancer cells resistance against cisplatin and paclitaxel. Meanwhile, we also analyzed the mechanism of chemotherapy resistance caused by IL-8 in ovarian cancer cells and its related signal pathways. We found that endogenous IL-8 could induce cisplatin and paclitaxel resistance in non-IL-8-expressing A2780 cells, while deletion of endogenous IL-8 expression in IL-8-overexpressing SKOV3 cells could recover the sensitivity of these cells to anticancer drugs. While IL-8 mediated chemotherapy resistance of ovarian cancer cells through decreasing proteolytic activation of caspase-3. Moreover, endogenous IL-8 significantly enhanced the expression of drug resistance-associated gene MDR1, and apoptosis-inhibiting genes Bcl-2, Bcl-xL and XIAP in sense IL-8-transfected A2780 cells, but reduced in antisense IL-8-transfected SKOV3 cells compared with the corresponding parental and control vector-transfected cells. It also found that wortmannin （PI3K inhibitor） and PD98059 （MEK1/2 inhibitor） could significantly antagonized IL-8-induced phosphorylation of Akt and ERK, respectively, and both of them blocked IL-8-induced cisplatin and paclitaxel resistance. Furthermore, the inhibitory effects of PD98059 and wortmannin were dependent on its concentration. These data suggest that IL-8-induced chemoresistance may be associated with the increase of both drug resistance-associated gene MDR1 and apoptosis-inhibiting g0enes Bcl-2, Bcl-xL and XIAP. as well as theactivation of Raf/MEK/ERK and PI3K/Akt. Therefore, modulation of IL-8 expression or its related signaling pathway may be a promising strategy of treatment for drug-resistant ovarian cancer.