Zhao Xia, Yang Weihua, Shi Changwen, Ma Wanshan, Liu Jianing, Wang Yunshan, Jiang Guosheng
The Central Laboratory, Qianfoshan Hospital of Shandong Province, Jinan 250014, China.
Tumour Biol. 2011 Apr;32(2):335-46. doi: 10.1007/s13277-010-0126-5. Epub 2010 Nov 27.
Recent studies have demonstrated that the histone deacetylation level was closely related to the genesis and development of tumors. Thus, activating histone acetyltransferases and/or suppressing histone deacetylases (HDACs) can become an approach for tumor chemotherapy. The histone acetylation regulation often results in the inhibition of cell proliferation, induction of cell apoptosis or differentiation, and cell cycle arrest in G1 phase. It has been demonstrated recently that the traditional anticonvulsant valproic acid was an efficient class I HDAC inhibitor (HDACI); however, its antitumor effect and mechanisms on gastric cancers so far has not been elucidated clearly. In the present study, gastric carcinoma cell lines BGC-823, HGC-27, and SGC-7901 were cultured with valproic acid (VPA) in vitro. The cell morphology was observed by invert microscope, the proliferation was detected by MTT assay, the apoptosis and cell cycle were analyzed by flow cytometry assay with Annexin V/PI and PI, the activities and protein expressions of Caspase 3, Caspase 8, Caspase 9 of BGC-823 cells were detected by spectrophotometry and indirect immunofluorescence technique, respectively. The protein expressions of Cyclin A, Cyclin D1, Cyclin E, P21(Waf/cip1) of BGC-823 cells were analyzed by indirect immunofluorescence assay, and messenger ribonucleic acid (mRNA) expressions were detected by RT-PCR assay. The results showed that the proliferation of three kinds of gastric carcinoma cells could be inhibited obviously by VPA, which was related to the apoptosis induction and cell cycle arrest in G1 phase. The intrinsic pathway (cytochrome C pathway) was chiefly involved in the mechanism of apoptosis, which was indicated by activation of Caspase 9 and Caspase 3. The extrinsic pathway was partially involved, with slight activation of Caspase 8. The mechanism underlying its effect on cell cycle arrest in G1 phase induction was due to the upregulation of P21(Waf/cip1), Mad1 expression and downregulation of Cyclin A, c-Myc expression.
近期研究表明，组蛋白去乙酰化水平与肿瘤的发生发展密切相关。因此，激活组蛋白乙酰转移酶和/或抑制组蛋白去乙酰化酶（HDACs）可成为肿瘤化疗的一种方法。组蛋白乙酰化调节通常会导致细胞增殖受抑制、细胞凋亡或分化诱导以及细胞周期阻滞于G1期。最近已证实，传统抗惊厥药丙戊酸是一种有效的I类组蛋白去乙酰化酶抑制剂（HDACI）；然而，其对胃癌的抗肿瘤作用及机制迄今尚未完全阐明。在本研究中，胃癌细胞系BGC - 823、HGC - 27和SGC - 7901在体外用丙戊酸（VPA）培养。通过倒置显微镜观察细胞形态，用MTT法检测细胞增殖，用Annexin V/PI和PI通过流式细胞术分析细胞凋亡和细胞周期，分别用分光光度法和间接免疫荧光技术检测BGC - 823细胞中Caspase 3、Caspase 8、Caspase 9的活性和蛋白表达。通过间接免疫荧光分析检测BGC - 823细胞中Cyclin A、Cyclin D1、Cyclin E、P21（Waf/cip1）的蛋白表达，并用RT - PCR法检测信使核糖核酸（mRNA）表达。结果表明，VPA可明显抑制三种胃癌细胞的增殖，这与诱导细胞凋亡和细胞周期阻滞于G1期有关。凋亡机制主要涉及内源性途径（细胞色素C途径），表现为Caspase 9和Caspase 3的激活。外源性途径部分参与，Caspase 8有轻微激活。其诱导细胞周期阻滞于G1期的作用机制是由于P21（Waf/cip1）、Mad1表达上调以及Cyclin A、c - Myc表达下调。
