Down-regulation of BiP/GRP78 sensitizes resistant prostate cancer cells to gene-therapeutic overexpression of REIC/Dkk-3
Down-regulation of BiP/GRP78 sensitizes resistant prostate cancer cells to gene-therapeutic overexpression of REIC/Dkk-3
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DOI：
10.1002/ijc.24764
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发表时间：
2010-04-01
影响因子：
6.4
通讯作者：
Huh, Nam-Ho
中科院分区：
文献类型：
--
作者：
Tanimoto, Ryuta;Sakaguchi, Masakiyo;Huh, Nam-Ho
我们最近发现，一种携带REIC/Dkk-3 （Ad-REIC）的腺病毒对多种人类癌症具有强大的肿瘤特异性细胞杀伤功能。也很明显，一些人类癌症对ad - reic诱导的细胞凋亡具有抗性。本研究的目的是确定抗Ad-REIC的分子机制。首先，我们从反复暴露于Ad-REIC的人前列腺癌细胞系PC3中分离出耐药克隆。腺病毒载体的感染效率和REIC/Dkk-3在抗性克隆中的表达水平与亲本PC3细胞相似。通过筛选ad - reic诱导的凋亡相关蛋白的水平和功能状态的改变，我们发现，在耐药细胞中，存在于er的伴侣蛋白BiP/GRP78的表达水平始终较高。BiP表达水平与Ad-REIC诱导的细胞凋亡率呈负相关。在体内和培养中，用siRNA下调BiP使耐药细胞对Ad-REIC敏感。这些结果表明，BiP是抗ad - reic诱导的细胞凋亡的主要决定因素。因此，BiP可用于诊断癌症的固有和获得性耐药，也可作为克服对基因治疗Ad-REIC耐药的靶分子。
We have recently shown that an adenovirus carrying REIC/Dkk-3 (Ad-REIC) exhibits a potent tumor-specific cell-killing function for various human cancers. It has also become evident that some human cancers are resistant to Ad-REIC-induced apoptosis. The aim of the present study was to determine the molecular mechanisms of resistance to Ad-REIC. First, we isolated resistant clones from a human prostate cancer cell line, PC3, after repeated exposure to Ad-REIC. Infection efficiency of the adenovirus vector and expression level of REIC/Dkk-3 in the resistant clones were similar to those in the parental PC3 cells. By screening for alteration in levels and functional status of proteins involved in Ad-REIC-induced apoptosis, we found that BiP/GRP78, an ER-residing chaperone protein, was expressed at higher levels consistently among resistant cells. Expression levels of BiP and rates of apoptosis induced by Ad-REIC were inversely correlated. Down-regulation of BiP with siRNA sensitized the resistant cells to Ad-REIC in vivo as well as in culture. These results indicate that BiP is a major determinant of resistance to Ad-REIC-induced apoptosis. Thus BiP is useful for diagnosis of inherent and acquired resistance of cancers and also as a target molecule to overcome resistance to the gene therapeutic Ad-REIC.