Overexpression of IL-6 but not IL-8 increases paclitaxel resistance of U-20S human osteosarcoma cells
Overexpression of IL-6 but not IL-8 increases paclitaxel resistance of U-20S human osteosarcoma cells
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DOI：
10.1006/cyto.2001.1008
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发表时间：
2002-03-07
期刊：
影响因子：
3.8
通讯作者：
Seide, MV
中科院分区：
文献类型：
--
作者：
Duan, Z;Lamendola, DE;Seide, MV
细胞因子IL-6最初被认为是免疫和炎症反应的调节剂，IL-8是血管生成的潜在调节剂，也调节许多肿瘤细胞的生长。选择对常见化疗剂具有多药耐药性的人癌细胞显示IL-6和IL-8的表达增加。为了确定IL-6或IL-8过表达是否直接导致耐药表型，使用pIRESneo双顺反子表达载体将IL-6或IL-8 cDNA引入紫杉醇敏感的人骨肉瘤细胞系U-20 S中。选择高IL-6或IL-8分泌的白细胞介素-6和IL-8转染子，并在耐药性测定中进行评价。两个IL-6和两个IL-8分泌克隆在培养物中表达10 ng/ml和1 ng/ml的IL-6或IL-8水平，而亲本U-20 S和pIRESneo载体转染的对照细胞分别表达0.005 ng/ml和0.1 ng/ml的IL-6和IL-8水平。与U-20 S相比，IL-6转染细胞的NITT细胞毒性显示对紫杉醇的抗性增加了5倍，对阿霉素的抗性增加了4倍。与亲本U-20 S相比，IL-6转染子中的米托蒽醌或拓扑替康抗性没有变化。IL-6转染子的北方分析表明，耐药表型与MDR-1、MRP-1或LRP水平的增加无关。Western分析也证实了IL-6转染子中P-糖蛋白水平没有改变。维拉帕米不能逆转转染细胞中的紫杉醇耐药性，这进一步支持MDR-1独立的耐药机制，罗丹明123排除数据进一步支持这一发现。与药物敏感的亲本U-2 OS相比，用紫杉醇处理IL-6转染的细胞显示U-2 OS（IL-6）对紫杉醇诱导的细胞凋亡具有显著更大的抗性，并且表现出降低的半胱天冬酶-3的蛋白水解活化。相反，与亲本细胞相比，U-2 OS（IL-8）转染子显示紫杉醇抗性没有明显增加。总之，虽然IL-6和IL-8在紫杉醇抗性细胞系中过表达，但只有IL-6有可能直接导致U-20 S中的紫杉醇和多柔比星抗性。这种耐药是通过非MDR-1途径。(C)2002爱思唯尔科技有限公司版权所有。
The cytokines IL-6, initially recognized as a regulator of immune and inflammatory response and IL-8, a potential regulator of angiogenesis, also regulate the growth of many tumor cells. Human cancer cells selected for multidrug resistance to common chemotherapeutic agents demonstrate increased expression of IL-6 and IL-8. To determine whether IL-6 or IL-8 overexpression contributes directly to the drug resistant phenotype, IL-6 or IL-8 cDNA were introduced into the paclitaxel sensitive human osteosarcoma cell line U-20S using the pIRESneo bicistronic expression vector. Interleukin-6 and IL-8 transfectants were selected for either high IL-6 or IL-8 secretion and evaluated in drug resistance assays. Two IL-6 and two IL-8 secreting clones express IL-6 or IL-8 levels of 10 ng/ml and I ng/ml in culture, while parental U-20S and pIRESneo vector transfected control cells express IL-6 and IL-8 levels of 0.005 ng/ml and 0.1 ng/ml, respectively. NITT cytotoxicity with IL-6 transfected cells demonstrates a five-fold increase in resistance to paclitaxel and a four-fold increase in resistance to doxorubicin as compared to U-20S. There are no changes in mitoxantrone or topotecan resistance in the IL-6 transfectants as compared to parental U-20S. Northern analysis of IL-6 transfectants demonstrates that the resistant phenotype is not related to increased levels of MDR-1, MRP-1, or LRP. Western analysis also confirms that P-glycoprotein levels are not altered in IL-6 transfectants. Further supporting an MDR-1 independent mechanism of drug resistance, verapamil cannot reverse paclitaxel resistance in transfected cells, findings further supported by rhodamine 123 exclusion data. Treatment of IL-6 transfected cells with paclitaxel, compared with drug-sensitive parental U-2OS shows U-2OS(IL-6) are significantly more resistant to apoptosis induced by paclitaxel and exhibit decreased proteolytic activation of caspase-3. In contrast U-2OS(IL-8) transfectants demonstrate no appreciable increase in paclitaxel resistance when compared with parental cells. In summary, while both IL-6 and IL-8 are overexpressed in paclitaxel resistant cell lines, only IL-6 has the potential to contribute directly to paclitaxel and doxorubicin resistance in U-20S. This resistance is through a non-MDR-1 pathway. (C) 2002 Elsevier Science Ltd. All rights reserved.