Objective: To investigate the effects of propranolol on the subcutaneous tumorigenesis of esophageal squamous cell carcinoma (ESCC) cells and the proliferation, migration, cell cycle, apoptosis and autophagy of ESCC cells and its possible molecular mechanisms. Methods: The cell proliferation was detected by MTT (methyl thiazol tetrazolium) assay: ESCC Eca109, KYSE-450 and TE-1 cells were routinely cultured. PBS (Phosphate buffer saline) group (without propranolol) and treated groups (40, 60, 80, 100 μmol/L propranolol) were set up with 5 wells in each group. After treatment for 0, 24, 48, 72 h, 10 μl (5 mg/ml) of MTT was added to each well, and the absorbance was measured at 490 nm. The cell migration was tested by Transwell assay: ESCC Eca109, KYSE-450 and TE-1 cells were routinely cultured, and PBS group (without propranolol) and treated groups (40, 60 μmol/L) were set up with 2 wells in each group. Photos were taken 40 h later, and the experiment was repeated for three times before statistical analysis. The cell cycle and apoptosis were detected by flow cytometry assay: ESCC Eca109, KYSE-450 and TE-1 cells were routinely cultured. PBS group (without propranolol) and treated group (80 μmol/L) were set up, fixed, stained, and fluorescence at 488 nm was detected. The protein levels were detected by Western blot: ESCC Eca109 and KYSE-450 cells were routinely cultured. PBS group (without propranolol) and treated groups (60, 80 μmol/L) were set up followed by gel electrophoresis, wet membrane transfer, and ECL imaging. The experiment was repeated for three times and then analyzed statistically. Subcutaneous tumor formation experiment in nude mice: 10 nude mice were assigned PBS group (without propranolol) and treated group (with propranolol). Five mice in each group were inoculated with 5×106 cells/100 μl (Eca109) into the right underarm. The treated group was given a gavage of 0.4 ml/kg (6 mg/kg) every other day, and the tumor size was measured every other day for 3 weeks. After 20 days, the nude mice were dislocated and sacrificed to take tumor tissue. Result: The results showed that propranolol inhibited the proliferation of Eca109, KYSE-450 and TE-1 cells with IC50 of around 70 μmol/L for 48 h. Eca109, KYSE-450 and TE-1 cell migration was inhibited by propranolol in a dose-dependent manner (P＜0.05); Propranolol blocked the cell cycle of Eca109 in G2/M phase, blocked the cell cycle of KYSE-450 and TE-1 in G0/G1 phase, and promoted apoptosis of three kinds of cells (P＜0.05). The results of cell fluorescence showed that LC3 fluorescence intensity of TE-1 was increased after 12 h, 24 h and 36 h treatment with propranolol (P＜0.05). Western blot results showed that compared with PBS group, the protein expressions of p-mTOR, p-Akt and cyclin D1 were down-regulated, while cleaved caspase 9 level was up-regulated (P＜0.05). The results of subcutaneous tumor formation in nude mice showed that the tumor weight of PBS group was (0.91±0.05)g, and that of the experimental group was(0.65±0.12)g, the difference was statistically significant (P＜0.05). Conclusion: Propranolol inhibits the proliferation, migration and cell cycle,promotes apoptosis and autophagy of ESCC cells, and inhibits subcutaneous tumor growth in nude mice. The mechanism might be related to the inhibition of PI3K/AKT/mTOR signaling pathway.
目的: 探索普萘洛尔对食管鳞癌细胞皮下成瘤和食管鳞癌(ESCC)细胞增殖、迁移、周期、凋亡、自噬的影响及其可能的分子机制。方法: MTT(噻唑蓝)检测细胞增殖:常规培养食管鳞癌Eca109、KYSE-450、TE-1细胞,设置PBS组(不加Propranolol),加药组(40、60、80、100 μmol/L ),每组5个复孔,分别处理0、24、48、72 h后,每孔加入MTT 10 μl(5 mg/ml),490 nm处测定吸光度值。Transwell检测迁移:常规培养食管鳞癌Eca109、KYSE-450、TE-1细胞,设置PBS组(不加Propranolol),加药组(40、60 μmol/L ),每组2个复孔,40 h后拍照,实验重复三次后统计学分析。流式细胞术检测细胞周期及凋亡:常规培养食管鳞癌Eca109、KYSE-450、TE-1细胞,设置PBS组(不加Propranolol),加药组(80 μmol/L ),固定、染色,检测488 nm处荧光。Western blot检测蛋白表达 :常规培养食管鳞癌Eca109、KYSE-450细胞,设置PBS组(不加Propranolol),加药组(60、80 μmol/L ),凝胶电泳,湿法转膜,ECL显影,实验重复三次后统计学分析。裸鼠皮下成瘤实验:10只裸鼠,设置PBS组(不加Propranolol)和Propranolol组(加药组),每组5只,均接种Eca109细胞5×106 cells/100 μl于右侧腋下,加药组隔日灌胃,每次0.4 ml(6 mg/kg),期间隔日测量肿瘤大小,持续3周。20 d后处死裸鼠取瘤体组织。结果: 结果显示Propranolol可抑制Eca109、KYSE-450、TE-1细胞增殖, 48h IC50均为70 μmol/L;抑制 Eca109、KYSE-450、TE-1细胞迁移,且具浓度依赖性(P＜0.05);阻滞Eca109细胞周期于G2/M期,阻滞KYSE-450细胞和TE-1细胞周期于G0/G1期,并促进三种细胞凋亡(P均＜0.05);细胞免疫荧光结果显示Propranolol处理TE-1细胞12 h、24 h、36 h后LC3荧光强度增加(P均＜0.05);Western blot结果显示与PBS组比较,加药组p-mTOR、p-Akt、cyclin D1蛋白表达量下调、cleaved caspase 9蛋白水平上调(均P＜0.05);裸鼠皮下成瘤结果显示对照组瘤重(0.91±0.05)g,实验组瘤重(0.65±0.12)g,差异具有统计学意义(P＜0.05)。结论: 普萘洛尔抑制ESCC细胞增殖、迁移、周期,促进其凋亡和自噬,并抑制裸鼠皮下肿瘤生长,其机制可能与其抑制PI3K/AKT/mTOR信号通路有关。.
Keywords: ESCC; apoptosis; autophagy; cell culture; cycle; migration; nude mice; proliferation; propranolol.