Hong Zhen-Ya, Yi Li-Sha, Miao Xin-Yu, Lu Yun-Ping, Zhou Jian-Feng, Liu Wen-Li
Department of Hematology, Tongji Hospital, Tongji Medical College, Huazhong University of Science &Technology, Wuhan, Hubei, 430030, P. R. China.
Ai Zheng. 2006 Aug;25(8):946-53.
BACKGROUND & OBJECTIVE: Histone deacetylase is overexpressed in a variety of cancers and is closely correlated with oncogenic factors. A histone-deacetylase inhibitor, trichostatin A (TSA), has been shown to induce apoptosis in many cancer cells at submicromolar concentrations. However, the mechanism remains unknown. This study was to investigate the underlying mechanism of trichostatin A on apoptosis of Molt-4 cells by characterizing the global gene expression profiles before and after TSA treatment.
PI single-labeled flow cytometry, MTT and DNA ladder were used to observe the effect of TSA on apoptosis of MOLT-4 cells and normal human peripheral blood mononuclear cells (PBMC). Microarray and reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were used to detect the differentially expressed genes of Molt-4 cells after incubation with TSA.
TSA could induce apoptosis in Molt-4 cells in a dose and time-dependent manner. Besides, the dose of TSA within the time duration which could induce significant apoptosis in Molt-4 cells did not demonstrate apparent cytotoxicity to PBMCs. After incubation with TSA for 9 hours, 313 genes were detected down-regulated by microarray. Proteins encoded by these genes included signal transduction molecules, transcription factors, enzymes etc., which were involved in the regulation of cell growth, differentiation and survival. STAT5A, MYC and ikaros were down-regulated by 80.4%, 77.3% and 83.1%, respectively. The changes of the three genes were confirmed by RT-PCR and the changes of STAT5A and MYC were further confirmed by Western blot.
The inhibition of cell growth and induction of apoptosis by TSA in Molt-4 cells may be due to the changes of pro-proliferation genes and anti-apoptosis genes.
组蛋白去乙酰化酶在多种癌症中过表达，且与致癌因素密切相关。一种组蛋白去乙酰化酶抑制剂曲古抑菌素A（TSA）已被证明在亚微摩尔浓度下可诱导多种癌细胞凋亡。然而，其机制尚不清楚。本研究旨在通过分析TSA处理前后的全基因组表达谱，探讨曲古抑菌素A诱导Molt-4细胞凋亡的潜在机制。
采用碘化丙啶（PI）单标记流式细胞术、MTT法和DNA梯状条带分析观察TSA对MOLT-4细胞和正常人外周血单个核细胞（PBMC）凋亡的影响。利用基因芯片、逆转录聚合酶链反应（RT-PCR）和蛋白质免疫印迹法检测TSA作用后Molt-4细胞中差异表达的基因。
TSA能以剂量和时间依赖的方式诱导Molt-4细胞凋亡。此外，在能诱导Molt-4细胞发生明显凋亡的时间范围内，TSA的剂量对PBMCs未表现出明显的细胞毒性。TSA作用9小时后，基因芯片检测到313个基因表达下调。这些基因编码的蛋白质包括信号转导分子、转录因子、酶等，它们参与细胞生长、分化和存活的调控。信号转导和转录激活因子5A（STAT5A）、原癌基因MYC和Ikaros分别下调了80.4%、77.3%和83.1%。RT-PCR证实了这三个基因的变化，蛋白质免疫印迹法进一步证实了STAT5A和MYC的变化。
TSA抑制Molt-4细胞生长并诱导其凋亡可能是由于促增殖基因和抗凋亡基因的改变所致。
