Enhancement of chemosensitivity toward peplomycin by calpastatin-stabilized NF-κB p65 in esophageal carcinoma cells:: possible involvement of Fas/Fas-L synergism
Enhancement of chemosensitivity toward peplomycin by calpastatin-stabilized NF-κB p65 in esophageal carcinoma cells:: possible involvement of Fas/Fas-L synergism
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DOI：
10.1007/s10495-006-6353-y
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发表时间：
2006-06-01
期刊：
影响因子：
7.2
通讯作者：
Hiwasa, T.
中科院分区：
文献类型：
--
作者：
Liu, T. -L.;Shimada, H.;Hiwasa, T.
本文比较了人食管癌细胞系T.Tn和YES-6对抗癌药物的敏感性。Tn细胞对培洛霉素（PEP）的耐药率高于YES-6细胞，但对喜树碱、丝裂霉素C和阿糖胞苷等抗癌药物的耐药率均低于YES-6细胞。Western blot分析显示T.Tn细胞中m-calpain和活化的mu-calpain的表达水平高于YES-6细胞。另一方面，YES-6细胞显示钙蛋白酶抑制剂的高表达水平，钙蛋白酶抑制剂是钙蛋白酶特异性内源性抑制剂。为了研究钙蛋白酶活性是否参与化疗敏感性，将钙蛋白酶抑制剂cDNA在诱导型表达载体中转染T.Tn细胞。钙蛋白酶抑制蛋白的诱导伴随着对PEP的化疗敏感性增加。随着钙蛋白酶抑制蛋白水平的增加，NF-κ B p65和Fas的表达水平也随之增加。由于纯化的m-或mu-钙蛋白酶在体外降解NF-κ B p65，因此钙蛋白酶抑制剂可能抑制钙蛋白酶介导的NF-κ B p65降解。转染钙蛋白酶抑制剂的T.Tn细胞经PEP处理后，Fas配体（Fas-L）蛋白水平升高，提示钙蛋白酶抑制剂诱导的Fas与PEP诱导的Fas-L之间存在协同作用。这些结果表明，calpain/calpastatin表达水平是预测人食管癌细胞对PEP敏感性的有效指标。
Chemosensitivity to anticancer drugs was compared between two human esophageal carcinoma cell lines, T.Tn and YES-6 cells. T.Tn cells were more resistant than YES-6 cells to peplomycin (PEP) but not to the other anticancer drugs such as camptothecin, mitomycin C and cytosine arabinoside. Western blot analysis showed higher expression levels of m-calpain and activated mu-calpain in T.Tn cells than in YES-6 cells. On the other hand, YES-6 cells showed a high expression level of calpastatin, which is a calpain-specific endogenous inhibitor. To investigate whether calpain activity was involved in the chemosensitivity, T.Tn cells were transfected with calpastatin cDNA in an inducible expression vector. The induction of calpastatin was accompanied by increased chemosensitivity to PEP. The increases in calpastatin levels were followed by serial increases in the expression levels of NF-kappa B p65 and Fas. Since purified m- or mu-calpain degraded NF-kappa B p65 in vitro, it is possible that calpastatin suppressed calpain-mediated degradation of NF-kappa B p65. Fas ligand (Fas-L) protein levels increased after treatment of the parental T.Tn and calpastatin-transfected cells with PEP, suggesting the synergism between calpastatin-induced Fas and PEP-induced Fas-L. These results suggest that calpain/calpastatin expression levels are effective markers for predicting the sensitivity of human esophageal carcinoma cells to PEP.