Down-regulation of Inhibition of Differentiation-1 via Activation of Activating Transcription Factor 3 and Smad Regulates REIC/Dickkopf-3-Induced Apoptosis
Down-regulation of Inhibition of Differentiation-1 via Activation of Activating Transcription Factor 3 and Smad Regulates REIC/Dickkopf-3-Induced Apoptosis
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DOI：
10.1158/0008-5472.can-08-0080
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发表时间：
2008-10-15
期刊：
影响因子：
11.2
通讯作者：
Kumon, Hiromi
中科院分区：
文献类型：
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作者：
Kashiwakura, Yuji;Ochiai, Kazuhiko;Kumon, Hiromi
REIC/Dickkopf-3（Dkk-3）是一种肿瘤抑制基因，已被用于基因治疗研究。我们的前期研究表明REIC/Dkk-3诱导前列腺癌细胞凋亡主要是由于c-Jun-NH 2激酶（JNK）磷酸化所致。然而，确切的机制，特别是调控JNK磷酸化的分子机制仍不清楚。在这项研究中，我们研究了参与JNK磷酸化的机制，在难治性癌症疾病的背景下，恶性间皮瘤（MM）。腺病毒介导的REIC/Dkk-3过表达主要通过JNK激活永生化MM细胞（211 H细胞）诱导凋亡。有趣的是，在REIC/Dkk-3过表达的211 H细胞中检测到分化抑制-1（Id-1）的转录下调。此外，Id-1表达的恢复拮抗REIC/Dkk-3诱导的JNK磷酸化和凋亡。用2.1-kb人Id-1启动子进行的诱变实验表明，激活转录因子3（ATF 3）和Smad相互作用及其各自的结合基序对于REIC/Dkk-3介导的Id-1启动子活性抑制是必不可少的。ATF 3的激活可能是由内质网应激诱导的。最后，我们在原位MM小鼠模型中显示了REIC/Dkk-3基因转移到胸膜腔中的强抗肿瘤作用。相对于对照肿瘤组织，REIC/Dkk-3处理的肿瘤组织显示Id-1 mRNA表达下调，磷酸化JNK表达增强，凋亡细胞数量增加。总之，我们首先发现，ATF 3和Smad都是至关重要的，协同参与下调Id-1，调节JNK磷酸化REIC/Dkk-3诱导的凋亡。因此，用REIC/Dkk-3进行基因治疗可能是MM的有希望的治疗工具[Cancer Res 2008;68（20）：8333-41]。
REIC/Dickkopf-3 (Dkk-3), a tumor suppressor gene, has been investigated in gene therapy studies. Our previous study suggested that REIC/Dkk-3-induced apoptosis mainly resulted from phosphorylation of c-Jun-NH2 kinase (JNK) in prostate cancer cells. However, the precise mechanisms, especially the molecular mechanisms regulating JNK phosphorylation, remain unclear. In this study, we investigated the mechanisms participating in JNK phosphorylation in the context of a refractory cancer disease, malignant mesothelioma (MM). Adenovirus-mediated overexpression of REIC/Dkk-3 induced apoptosis mainly through JNK activation in immortalized MM cells (211H cells). Interestingly, transcriptional down-regulation of inhibition of differentiation-1 (Id-1) was detected in REIC/Dkk-3-overexpressed 211H cells. Moreover, restoration of Id-1 expression antagonized REIC/Dkk-3-induced JNK phosphorylation and apoptosis. Mutagenesis experiments with the 2.1-kb human Id-1 promoter revealed that activating transcription factor 3 (ATF3) and Smad interaction, with their respective binding motifs, was essential for REIC/Dkk-3-mediated suppression of Id-1 promoter activity. ATF3 activation was probably induced by endoplasmic reticulum stress. Finally, we showed strong antitumor effects from REIC/Dkk-3 gene transfer into the pleural cavity in an orthotopic MM mouse model. Relative to control tumor tissue, REIC/Dkk-3-treated tumor tissue showed down-regulated expression of Id-1 mRNA, enhanced expression of phosphorylated JNK, and an increased number of apoptotic cells. In summary, we first showed that both ATF3 and Smad were crucially and synergistically involved in down-regulation of Id-1, which regulated JNK phosphorylation in REIC/Dkk-3-induced apoptosis. Thus, gene therapy with REIC/Dkk-3 may be a promising therapeutic tool for MM. [Cancer Res 2008;68(20):8333-41]