Huang Run-Yue, Chu Yong-Liang, Jiang Ze-Bo, Chen Xiu-Ming, Zhang Xian, Zeng Xing
Department of Rheumatology, The Second Affiliated Hospital, Guangzhou University of Chinese Medicine (Guangdong Provincial Hospital of Chinese Medicine), Guangzhou, China.
Cell Physiol Biochem. 2014;33(2):375-88. doi: 10.1159/000356677. Epub 2014 Feb 6.
BACKGROUND/AIMS: The effects of glycyrrhizin treatment in lung cancer remain undetermined, despite extensive studies of the anti-tumor activities of glycyrrhizin.
Lung adenocarcinoma A549 and NCI-H23 cell lines were used in this study. Cell growth was examined by MTS assays, while apoptosis and cell cycle were determined by flow cytometric analysis. Both real-time PCR and western blotting were used to examine the expression levels of thromboxane synthase (TxAS), and TxAS activity was measured using EIA detection of the biosynthesis of TxA2. TxAS was overexpressed in NCI-H23 cells by transfection with TxAS cDNA, while TxAS was inhibited by transfection with TxAS siRNA in A549 cells. For the mouse model of lung adenocarcinoma, the effects of glycyrrhizin on tumor growth were analyzed by western blot evaluation of TxAS, PTEN and survivin. TxAS activity was determined by EIA assay.
Glycyrrhizin suppressed cell growth in A549 cells, but not in NCI-H23 cells, by induction of apoptosis. TxAS was overexpressed in A549 cells, but the TxAS levels in NCI-H23 cells were minimal. Moreover, TxAS expression and activity were suppressed by glycyrrhizin. Glycyrrhizin had no additive effects with TxAS siRNA knockdown in suppressing A549 cell growth, whereas it completely suppressed cell growth of NCI-H23 cells transfected with TxAS cDNA. These results were further confirmed by the in vivo study.
Our study suggests that the anti-tumor effect of glycyrrhizin in lung adenocarcinoma is, at least in part, TxAS-dependent. Therefore, glycyrrhizin is a promising anti-cancer agent for the treatment of lung adenocarcinoma.
背景/目的：尽管对甘草酸的抗肿瘤活性进行了广泛研究，但其对肺癌的治疗效果仍不明确。
本研究采用肺腺癌A549和NCI-H23细胞系。通过MTS法检测细胞生长，采用流式细胞术分析细胞凋亡和细胞周期。运用实时定量PCR和蛋白质印迹法检测血栓素合酶（TxAS）的表达水平，并使用EIA法检测TxA2生物合成来测定TxAS活性。通过转染TxAS cDNA使NCI-H23细胞中TxAS过表达，而在A549细胞中转染TxAS siRNA抑制TxAS。对于肺腺癌小鼠模型，通过蛋白质印迹法评估TxAS、PTEN和生存素，分析甘草酸对肿瘤生长的影响。通过EIA法测定TxAS活性。
甘草酸通过诱导凋亡抑制A549细胞的生长，但对NCI-H23细胞无此作用。A549细胞中TxAS过表达，而NCI-H23细胞中TxAS水平极低。此外，甘草酸可抑制TxAS的表达和活性。在抑制A549细胞生长方面，甘草酸与TxAS siRNA敲低无相加作用，而它可完全抑制转染TxAS cDNA的NCI-H23细胞的生长。体内研究进一步证实了这些结果。
我们的研究表明，甘草酸对肺腺癌的抗肿瘤作用至少部分依赖于TxAS。因此，甘草酸是一种有前景的用于治疗肺腺癌的抗癌药物。
