Division of Basic Radiation Bioscience, Korea Institute of Radiological and Medical Sciences, Seoul, 01812, Republic of Korea.
Division of Basic Radiation Bioscience, Korea Institute of Radiological and Medical Sciences, Seoul, 01812, Republic of Korea.
J Dermatol Sci. 2018 Apr;90(1):13-20. doi: 10.1016/j.jdermsci.2017.12.011. Epub 2017 Dec 21.
Histone deacetylase (HDAC) is an enzyme that regulates gene expression, cell cycle arrest, apoptosis and modulation of various pathways. HDAC inhibitors (HDACis) can modulate these pathways by hyper-acetylating target proteins, thereby acting as cancer chemotherapeutic agents.
One of HDACis, suberoylanilide hydroxamic acid (SAHA), has been found to regulate the Smad signaling pathway, by an as yet unclear mechanism. This study therefore investigated the mechanism by which SAHA regulates Smad signaling in the melanoma cell line SK-Mel-5.
Cell proliferation was assessed by MTT assays and fluorescence activated cell sorter (FACS) analysis. The activation of Smad signaling pathway was assessed by western blots analysis. The transcriptions of target genes were checked by RT-PCR and dual luciferase assay.
Treatment with SAHA inhibited the proliferation of SK-Mel-5 cells, enhanced the phosphorylation of R-Smad, and up-regulated p21 protein. Surprisingly, R-Smad was also activated by conditioned medium from SAHA-treated SK-Mel-5 cells. An analysis of the conditioned medium showed that activin A was responsible for the activation of R-Smad. SAHA treatment enhanced the level of activin A mRNA, increasing the level of activin A in the secretome. The activity of the SAHA-treated secretome could be eliminated by pre-incubation with antibody to activin A. In addition, activin A supplemented medium could mimic the effect of the SAHA-treated secretome.
These findings indicate that the anti-cancer function of SAHA is mediated, at least in part, by the upregulation of activin A.
组蛋白去乙酰化酶（HDAC）是一种调节基因表达、细胞周期停滞、细胞凋亡和多种途径的酶。HDAC 抑制剂（HDACi）可以通过超乙酰化靶蛋白来调节这些途径，从而作为癌症化疗药物。
HDACi 中的一种，丁酸钠（SAHA），已被发现通过一种尚未明确的机制调节 Smad 信号通路。因此，本研究旨在研究 SAHA 调节 SK-Mel-5 黑素瘤细胞系中 Smad 信号通路的机制。
通过 MTT 检测和荧光激活细胞分选（FACS）分析评估细胞增殖。通过 Western blot 分析评估 Smad 信号通路的激活。通过 RT-PCR 和双荧光素酶检测检查靶基因的转录。
SAHA 处理抑制 SK-Mel-5 细胞的增殖，增强 R-Smad 的磷酸化，并上调 p21 蛋白。令人惊讶的是，R-Smad 也被 SAHA 处理的 SK-Mel-5 细胞的条件培养基激活。对条件培养基的分析表明，激活素 A 负责 R-Smad 的激活。SAHA 处理增强了激活素 A mRNA 的水平，增加了分泌组中的激活素 A 水平。用激活素 A 抗体预先孵育可以消除 SAHA 处理分泌组的活性。此外，补充激活素 A 的培养基可以模拟 SAHA 处理分泌组的作用。
这些发现表明，SAHA 的抗癌功能至少部分是通过上调激活素 A 介导的。
