Enhancement of cisplatin cytotoxicity by SAHA involves endoplasmic reticulum stress-mediated apoptosis in oral squamous cell carcinoma cells
Enhancement of cisplatin cytotoxicity by SAHA involves endoplasmic reticulum stress-mediated apoptosis in oral squamous cell carcinoma cells
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DOI：
10.1007/s00280-009-0969-x
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发表时间：
2009-03
影响因子：
3
通讯作者：
Maiko Suzuki;Manabu Endo;F. Shinohara;S. Echigo;H. Rikiishi
中科院分区：
文献类型：
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作者：
Maiko Suzuki;Manabu Endo;F. Shinohara;S. Echigo;H. Rikiishi
目的研究组蛋白去乙酰化酶抑制剂辛二酰苯胺异羟肟酸（suberoylanilide hydroxamic acid，SAHA）对顺铂（cis-dammine dichloropatinum（II），CDDP）诱导口腔鳞癌细胞凋亡的影响。我们研究的作用，内质网（ER）的压力在增强SAHA对CDDP的效果，相比ER应激thapsigargin.MethodsWe选择OSCC细胞系HSC-3，以确定各种细胞系之间的SAHA增强细胞毒性的机制。将HSC-3细胞与CDDP/SAHA共同孵育48 h后，采用MTT法和TUNEL法检测细胞对CDDP的敏感性。Western blot分析检测ER相关分子的表达，流式细胞术检测caspase活性。ResultsTreatment with CDDP/SAHA potentially induced apoptosis in HSC-3 cells with a significant increase in caspase-4 and-12 functions.例如，60%的细胞在用CDDP/SAHA处理48小时后变得凋亡。此外，SAHA单独快速诱导真核翻译起始因子-2（eIF 2）α持续磷酸化，其在ER应激期间上调。通过salubrinal（eIF 2 α去磷酸化抑制剂）抑制ER应激，消除了SAHA对CDDP细胞毒性的增强作用。磷酸化Akt的水平在SAHA处理的细胞中降低，这反过来与蛋白磷酸酶1（PP 1）的活性增加有关，蛋白磷酸酶1是Akt.ConclusionThese数据表明，上调特异性ER应激相关事件是SAHA增强CDDP诱导的细胞凋亡机制的一个组成部分，PP 1上调后Akt去磷酸化在SAHA诱导CDDP凋亡中起重要作用。
PurposeThe histone deacetylase inhibitor, suberoylanilide hydroxamic acid (SAHA), enhances cisplatin [cis-diammine dichloroplatinum (II)] (CDDP)-induced apoptosis in the oral squamous cell carcinoma (OSCC) cell line by complex, multifunctional mechanisms. We investigated the role of endoplasmic reticulum (ER) stress in the enhancing effect of SAHA on CDDP, compared with the ER stressor thapsigargin.MethodsWe chose OSCC cell line HSC-3 to ascertain the mechanism of SAHA-enhanced cytotoxicity among various cell lines. HSC-3 cells were incubated with CDDP/SAHA for 48 h, followed by the assessment of cell chemosensitivity to CDDP with MTT and TUNEL assays. Western blot analysis was used to detect the expressions of ER-related molecules, and flow cytometry was used to monitor caspase activity.ResultsTreatment with CDDP/SAHA potently induced apoptosis in HSC-3 cells with a significant increase in caspase-4 and -12 functions. For example, 60% of cells became apoptotic after 48 h of treatment with CDDP/SAHA. In addition, SAHA alone rapidly induced sustained phosphorylation of eukaryotic translation initiation factor-2 (eIF2)α, which is up-regulated during ER stress. Inhibition of ER stress by salubrinal, an inhibitor of eIF2α dephosphorylation, abrogated SAHA’s enhancement of CDDP cytotoxicity. Levels of phospho-Akt are decreased in SAHA-treated cells, and this is in turn associated with increased activity of protein phosphatase 1 (PP1) by SAHA, the phosphatase upstream of Akt.ConclusionThese data indicate that up-regulation of specific-ER stress-associated events is an integral part of the mechanism by which SAHA enhances CDDP-induced apoptosis, and PP1 up-regulation followed by Akt dephosphorylation plays an important role in SAHA-enhanced CDDP apoptosis.