Kim Ki Hyung, Xie Yanhua, Tytler Ewan M, Woessner Richard, Mor Gil, Alvero Ayesha B
Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, New Haven, CT, USA.
J Transl Med. 2009 Jul 20;7:63. doi: 10.1186/1479-5876-7-63.
We previously described a sub-population of epithelial ovarian cancer (EOC) cells with a functional TLR-4/MyD88/NF-kappaB pathway (Type I EOC cells), which confers the capacity to respond to Paclitaxel, a known TLR-4 ligand, by enhancing NF-kappaB activity and upregulating cytokine secretion - events that are known to promote tumor progression. It is therefore important to distinguish those patients that should not receive Paclitaxel; it is also important to identify alternative chemotherapy options that would benefit this sub-group of patients. The objective of this study is to determine if the KSP inhibitor, ARRY-520, can be a substitute for Paclitaxel in patients with Type I EOC.
EOC cells isolated from either ascites or tumor tissue were treated with increasing concentrations of ARRY-520 or Paclitaxel and cell viability determined. Activation of the apoptotic pathway was determined using Western blot analysis. Mitochondrial integrity was quantified using JC1 dye. Cytokine profiling was performed from supernatants using xMAP technology. NF-kappaB activity was measured using a Luciferase reporter system. In vivo activity was determined using a subcutaneous xenograft mouse model.
ARRY-520 and Paclitaxel exhibited the same cytotoxic effect on Type I and II cells. The GI50 at 48 h for Type II EOC cells was 0.0015 microM and 0.2 microM for ARRY-520 and Paclitaxel, respectively. For Type I EOC cells, the GI50 at 48 h was > 3 microM and >20 microM for ARRY-520 and Paclitaxel, respectively. Decrease in the number of viable cells was accompanied by mitochondrial depolarization and caspase activation. Unlike Paclitaxel, ARRY-520 did not induce NF-kappaB activation, did not enhance cytokine secretion, nor induce ERK phosphorylation in Type I EOC cells.
Administration of Paclitaxel to patients with high percentage Type I cancer cells could have detrimental effects due to Paclitaxel-induced enhancement of NF-kappaB and ERK activities, and cytokine production (e.g. IL-6), which promote chemoresistance and tumor progression. ARRY-520 has similar anti-tumor activity in EOC cells as that of Paclitaxel. However, unlike Paclitaxel, it does not induce these pro-tumor effects in Type I cells. Therefore, the KSP inhibitor ARRY-520 may represent an alternative to Paclitaxel in this subgroup of EOC patients.
我们之前描述了上皮性卵巢癌（EOC）细胞的一个亚群，其具有功能性TLR-4/MyD88/NF-κB信号通路（I型EOC细胞），该通路赋予细胞对已知的TLR-4配体紫杉醇作出反应的能力，即通过增强NF-κB活性和上调细胞因子分泌来实现，而这些事件已知会促进肿瘤进展。因此，区分那些不应接受紫杉醇治疗的患者很重要；识别对这一亚组患者有益的替代化疗方案也很重要。本研究的目的是确定KSP抑制剂ARRY-520是否可替代紫杉醇用于I型EOC患者。
用浓度递增的ARRY-520或紫杉醇处理从腹水或肿瘤组织中分离出的EOC细胞，并测定细胞活力。使用蛋白质免疫印迹分析确定凋亡途径的激活情况。使用JC1染料定量线粒体完整性。使用xMAP技术从细胞上清液中进行细胞因子分析。使用荧光素酶报告系统测量NF-κB活性。使用皮下异种移植小鼠模型确定体内活性。
ARRY-520和紫杉醇对I型和II型细胞表现出相同的细胞毒性作用。II型EOC细胞在48小时时的半数生长抑制浓度（GI50），ARRY-520为0.0015微摩尔，紫杉醇为0.2微摩尔。对于I型EOC细胞，48小时时的GI50，ARRY-520>3微摩尔，紫杉醇>20微摩尔。活细胞数量的减少伴随着线粒体去极化和半胱天冬酶激活。与紫杉醇不同，ARRY-520在I型EOC细胞中不诱导NF-κB激活，不增强细胞因子分泌，也不诱导ERK磷酸化。
对I型癌细胞比例高的患者使用紫杉醇可能会产生有害影响，因为紫杉醇会诱导NF-κB和ERK活性增强以及细胞因子产生（如IL-6），从而促进化疗耐药性和肿瘤进展。ARRY-520在EOC细胞中具有与紫杉醇相似的抗肿瘤活性。然而，与紫杉醇不同，它在I型细胞中不会诱导这些促肿瘤效应。因此，KSP抑制剂ARRY-520可能是这一亚组EOC患者中紫杉醇的替代药物。
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