Mesothelin inhibits paclitaxel-induced apoptosis through the PI3K pathway
Mesothelin inhibits paclitaxel-induced apoptosis through the PI3K pathway
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DOI：
10.1042/bj20082196
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发表时间：
2009-12-15
影响因子：
4.1
通讯作者：
Cheng, Wen-Fang
中科院分区：
文献类型：
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作者：
Chang, Ming-Cheng;Chen, Chi-An;Cheng, Wen-Fang
中间蛋白是一种分泌蛋白，在一些癌症中过度表达，但其确切功能尚不清楚。本研究的目的是评估间充质蛋白的可能功能。采用实时荧光定量聚合酶链式反应、逆转录聚合酶链式反应、细胞毒实验、细胞增殖实验、Hoechst染色检测细胞凋亡率、流式细胞仪检测caspase3和7活性、免疫沉淀和免疫印迹等方法。用实时荧光定量聚合酶链式反应检测紫杉醇耐药卵巢癌患者癌组织中间皮素的表达水平高于紫杉醇敏感卵巢癌患者(耐药组和敏感组的平均交叉点变化值分别为26.9+/-0.4和34.3+/-0.7，P<；0.001)。间充质素能保护细胞免受紫杉醇诱导的细胞凋亡。无论细胞是外源性间皮蛋白还是间皮蛋白转染体，Bcl2家族成员如Bcl2和Mcl 1的蛋白表达均显著增加。此外，间硫蛋白处理的细胞显示PI3K(磷酸肌醇3-激酶)和ERK(细胞外信号调节激酶)1/2的P85亚单位快速酪氨酸磷酸化，以增强MAPK(丝裂原活化蛋白激酶)的活性。抑制PI3K活性，但不抑制MAPK活性，可抑制细胞的抗凋亡能力，改变Bcl2家族对Mesothelin的反应。因此，间充质素能抑制紫杉醇诱导的细胞死亡，其机制主要是通过PI3K信号转导调控Bcl2家族的表达。间甲硫蛋白是降低细胞毒药物耐药性的潜在靶点。
Mesothelin, a secreted protein, is overexpressed in some cancers, but its exact function remains unclear. The aim of the present Study was to evaluate the possible function of mesothelin. Real-time PCR, RT (reverse transcription)-PCR, cytotoxicity assays, proliferative assays, apoptotic assays by Hoechst staining, detection of active caspases 3 and 7 by flow cytometric analysis, and immunoprecipitation and immunoblotting were performed. Cancer tissues in paclitaxel-resistant ovarian cancer patients expressed higher levels of mesothelin as assessed using real-time PCR than paclitaxel-sensitive ovarian cancer patients (the mean crossing point value change of mesothelin was 26.9 +/- 0.4 in the resistant group and 34.3 +/- 0.7 for the sensitive group; P < 0.001). Mesothelin also protected cells from paclitaxel-induced apoptosis. The protein expression of Bcl-2 family members, Such as Bcl-2 and Mcl-1, was significantly increased regardless of whether cells were treated with exogenous mesothelin or were mesothelin-transfectants. Furthermore, mesothelin-treated cells revealed rapid tyrosine phosphorylation of the p85 subunit of PI3K (phosphoinositide3-kinase) and ERK (extracellular-signal-regulated kinase) 1/2 for enhancing MAPK (mitogen-activated protein kinase) activity. The anti-apoptotic ability was suppressed and the express ion of Bcl-2 family in response to mesothelin was altered by inhibiting PI3K activity, but not by inhibiting MAPK activity. Thus mesothelin can inhibit paclitaxel-induced cell death mainly by involving PI3K signalling in the regulation of Bcl-2 family expression. Mesothelin is a potential target in reducing resistance to cytotoxic drugs.