Objective: To investigate the mechanism mediating the inhibitory effect of chidamide on esophageal squamous cell carcinoma (ESCC) cells.
Methods: ESCC cell lines KYSE-150, KYSE-450 and KYSE-510 were treated with 5, 10, 20, or 40 μmol/L of chidamide, and the changes in cell proliferation, colony-forming capacity, cell apoptosis and cell cycle were assessed using MTT aasay, colony formation experiment and flow cytometry. Western blotting was performed to detect the expression levels of cleaved caspase-3, cleaved PARP, p21, cyclin D1, p-Akt, p-ERK1/2, γH2AX, H3K9ac, and Ki-67. In a nude mouse model bearing subcutaneous ESCC xenografts, the effects of intraperitoneal injection of 20 mg/kg chidamide for 3 days on tumor size and body weight were observed every 3 days, and Ki-67 and CD31 expressions in the tumor tissues were detected using immunohistochemistry. Tubular formation experiment was used to examine the effect of chidamide on tubular formation of human umbilical vein endothelial cells (HUVECs) in vitro.
Results: In cultured ESCC cell lines, chidamide significantly inhibited cell proliferation and colony formation (P < 0.05), promoted cell apoptosis, and increased the percentage of G0/G1 phase cells (all P < 0.01). Chidamide obviously up-regulated cleaved caspase-3, cleaved PARP, p21, γH2AX, and H3K9ac and down-regulated cyclin D1, p-Akt and p-ERK1/2, and Ki-67 in the cells (P < 0.01). In the tumor-bearing mouse models, treatment with chidamide significantly reduced the tumor volume (P < 0.05), tumor to body weight ratio (P < 0.01), and the expression levels of Ki-67 and CD31 in the tumors (P < 0.01). Chidamide also significantly inhibited tubule formation in cultured HUVECs (P < 0.05).
Conclusion: Chidamide inhibits proliferation, induces apoptosis and blocks cell cycle of ESCC cells possibly by inhibiting the PI3K/Akt and ERK1/2 pathways and increasing DNA damage. Chidamide also inhibits subcutaneous tumorigenesis of ESCC cells in mice by inhibiting tumor cell proliferation and angiogenesis.
目的: 研究西达本胺对食管鳞癌细胞(ESCC)的增殖、周期、凋亡、皮下移植瘤的影响及作用机制。
方法: KYSE-150细胞、KYSE-450细胞、KYSE-510细胞分为对照组和不同浓度西达本胺(5、10、20、40 μmol/L)处理组。MTT、克隆形成实验、流式细胞术分别检测西达本胺对细胞增殖、细胞克隆形成、细胞凋亡、细胞周期的影响。Western blot检测cleaved caspase-3、cleaved PARP、p21、cyclin D1、p-Akt、p-ERK1/2、γH2AX、H3K9ac、Ki-67水平。在食管癌细胞裸鼠移植瘤模型中,每3 d观察腹腔注射20 mg/kg西达本胺(3 d/次)对肿瘤大小和裸鼠质量的影响,并采用免疫组化检测肿瘤组织中Ki-67和CD31的表达。小管形成实验检测西达本胺对人脐静脉内皮细胞(HUVECs)小管形成的影响。
结果: 西达本胺抑制食管癌细胞增殖及克隆形成(P < 0.05)。西达本胺组细胞凋亡率较对照组增加,G0/G1期比例增加(P < 0.01)。西达本胺上调cleaved caspase-3、cleaved PARP、p21,下调cyclin D1、p-Akt、p-ERK1/2,上调γH2AX、H3K9ac,下调Ki-67(P < 0.01)。与对照组相比,西达本胺组肿瘤体积减小(P < 0.05),瘤质量比降低(P < 0.01),肿瘤Ki-67和CD31表达降低(P < 0.01)。西达本胺抑制HUVECs小管形成(P < 0.05)。
结论: 西达本胺抑制食管鳞癌细胞增殖、诱导细胞凋亡、阻滞细胞周期,可能与抑制PI3K/Akt、ERK1/2通路及增加DNA损伤相关。西达本胺通过抑制食管鳞癌细胞增殖和组织血管生成抑制食管鳞癌细胞皮下成瘤。
Keywords: apoptosis; cell cycle; chidamide; esophageal squamous cell carcinoma; proliferation.