Chen Jin-Cherng, Hwang Juen-Haur
Department of Neurosurgery, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chiayi, Taiwan.
School of Medicine, Tzu Chi University, Hualien, Taiwan.
Tzu Chi Med J. 2016 Jul-Sep;28(3):103-108. doi: 10.1016/j.tcmj.2016.06.005. Epub 2016 Aug 1.
The prognosis of patients with glioblastoma remains poor even after various treatments such as surgery, radiotherapy, and chemotherapy. Thus, development of new drugs is urgently needed. The mechanisms underlying the cytotoxicity of caffeine in glioma cells are not clearly understood. This study aimed to assess the activities of histone deacetylase 1 (HDAC1) and histone acetyltransferase (p300) in RT2 glioma cells treated with caffeine.
Cell viability and activity of HDAC1 and p300 in RT2 glioma cells were assayed after treatment with caffeine for 48 hours.
Cell viability decreased significantly after treatment with 0.5mM, 1mM, and 2mM caffeine. HDAC1 protein activity decreased significantly with various concentrations of caffeine, whereas the activity of p300 increased significantly. In addition, the viability of RT2 cells remained high, but HDAC1 activity decreased, and p300 activity increased markedly with 0.5mM caffeine treatment. We used microRNA and small interfering RNA (siRNA) to regulate HDAC1 and p300 to further understand the impact on glioblastomas. siRNA downregulated p300 and thus increased the viability of RT2 cells, therefore, caffeine combined with siRNA abolished the efficacy of caffeine, which confirmed that caffeine upregulated p300 and reduced cell viability. We also found increased HDAC1 activity when RT2 cells were treated with a combination of caffeine and miR-449a and thus increased the viability of RT2 cells.
Our data suggest that a new strategy, caffeine, could increase glioma cell death by decreasing HDAC1 activity and/or by increasing p300 activity. The changes in HDAC1 and p300 activities appeared to occur earlier than loss of RT2 cells.
即使经过手术、放疗和化疗等多种治疗，胶质母细胞瘤患者的预后仍然很差。因此，迫切需要开发新药。咖啡因对胶质瘤细胞的细胞毒性机制尚不清楚。本研究旨在评估咖啡因处理的RT2胶质瘤细胞中组蛋白去乙酰化酶1（HDAC1）和组蛋白乙酰转移酶（p300）的活性。
用咖啡因处理RT2胶质瘤细胞48小时后，检测细胞活力以及HDAC1和p300的活性。
用0.5mM、1mM和2mM咖啡因处理后，细胞活力显著降低。不同浓度的咖啡因使HDAC1蛋白活性显著降低，而p300的活性显著增加。此外，用0.5mM咖啡因处理时，RT2细胞的活力仍然很高，但HDAC1活性降低，p300活性显著增加。我们使用微小RNA和小干扰RNA（siRNA）来调节HDAC1和p300，以进一步了解对胶质母细胞瘤的影响。siRNA下调p300，从而增加RT2细胞的活力，因此，咖啡因与siRNA联合使用消除了咖啡因的疗效，这证实了咖啡因上调p300并降低细胞活力。我们还发现，当RT2细胞用咖啡因和miR-449a联合处理时，HDAC1活性增加，从而增加了RT2细胞的活力。
我们的数据表明，一种新的策略——咖啡因，可以通过降低HDAC1活性和/或增加p300活性来增加胶质瘤细胞死亡。HDAC1和p300活性的变化似乎比RT2细胞的死亡更早出现。
