Department of Pharmaceutical Sciences, South Dakota State University, Box 2202 C, Brookings, SD 57007, USA.
Exp Biol Med (Maywood). 2011 Nov;236(11):1351-9. doi: 10.1258/ebm.2011.011030. Epub 2011 Sep 9.
Honokiol is a plant lignan isolated from bark and seed cones of Magnolia officinalis. Recent studies from our laboratory indicated that honokiol pretreatment decreased ultraviolet B-induced skin cancer development in SKH-1 mice. The aim of the present investigation was to study the effects of honokiol on human epidermoid squamous carcinoma A431 cells and to elucidate possible mechanisms involved in preventing skin cancer. A431 cells were pretreated with different concentrations of honokiol for a specific time period and investigated for effects on apoptosis and cell cycle analysis. Treatment with honokiol significantly decreased cell viability and cell proliferation in a concentration- and time-dependent manner. Honokiol pretreatment at 50 μmol/L concentration induced G0/G1 cell cycle arrest significantly (P < 0.05) and decreased the percentage of cells in the S and G2/M phase. Honokiol down-regulated the expression of cyclin D1, cyclin D2, Cdk2, Cdk4 and Cdk6 proteins and up-regulated the expression of Cdk's inhibitor proteins p21 and p27. Pretreatment of A431 cells with honokiol leads to induction of apoptosis and DNA fragmentation. These findings indicate that honokiol provides its effects in squamous carcinoma cells by inducing cell cycle arrest at G0/G1 phase and apoptosis.
厚朴酚是从厚朴树皮和种子中分离得到的植物木脂素。我们实验室的最近研究表明，厚朴酚预处理可减少 UVB 诱导的 SKH-1 小鼠皮肤癌的发生。本研究旨在研究厚朴酚对人表皮鳞癌细胞 A431 的影响，并阐明其预防皮肤癌的可能机制。将 A431 细胞用不同浓度的厚朴酚预处理特定时间，并研究其对细胞凋亡和细胞周期分析的影响。厚朴酚处理以浓度和时间依赖的方式显著降低细胞活力和细胞增殖。50μmol/L 浓度的厚朴酚预处理可显著诱导 G0/G1 细胞周期停滞（P<0.05），并降低 S 和 G2/M 期细胞的百分比。厚朴酚下调 cyclin D1、cyclin D2、Cdk2、Cdk4 和 Cdk6 蛋白的表达，并上调 Cdk 抑制剂蛋白 p21 和 p27 的表达。厚朴酚预处理 A431 细胞可诱导细胞凋亡和 DNA 片段化。这些发现表明，厚朴酚通过诱导 G0/G1 期细胞周期停滞和细胞凋亡来发挥其在鳞癌细胞中的作用。
