丁酸钠和1,25-(OH)2D3对人结肠癌细胞增殖和hTERT表达的影响

摘要

Background: Telomerase activity plays a crucial role in the immortalization of tumor cells and is tightly regulated by human telomerase reverse transcriptase (hTERT). Bioactive agents such as sodium butyrate and lα,25-dihydroxyvitamin D3 [1,25-(OH)2D3] have been demonstrated to have a potential anti-tumor effect. Aims: To investigate the effect of sodium butyrate and 1,25-(OH)2D3 on proliferation of human colon cancer cells and its potential mechanism. Methods:Human colon cancer HT29 cells were treated with sodium butyrate (0.5-2.0 mmol/L), 1,25-(OH)2D3 (10-8-10-6mol/L) and their combination [1.0 mmol/L sodium butyrate + 10-7mol/L 1,25-(OH)2D3], respectively. The growth inhibition of HT29 cells was measured by MTT assay, the cell cycle and apoptosis were assessed by flow cytometry, and hTERT mRNA expression was determined by RT-PCR. Results: Both sodium butyrate and 1,25-(OH)2D3 inhibited the growth of HT29 cells in a dose- and time-dependent manner. Sodium butyrate (1.0 mmol/L) and 1,25-(OH)2D3 (10-7mol/L) could arrest cell cycle in G0/G1 phase, induce apoptosis, and down-regulate hTERT mRNA expression in HT29 cells. Co-administration of sodium butyrate and 1,25-(OH)2D3 was more effective than used alone (P＜0.05). Conclusions: Sodium butyrate and 1,25(OH)2D3 can inhibit the proliferation of human colon cancer cells. The mechanism might be related to inhibition of telomerase activity, arrest of cell cycle and induction of apoptosis by down-regulating hTERT expression. Co-administation of the two drugs has synergistic effect on human colon cancer cells.%背景:端粒酶在肿瘤细胞永生化过程中起重要作用,人端粒酶逆转录酶(hTERT)是调节端粒酶活性的关键因素.有研究发现生物活性制剂丁酸钠和1α,25-二羟维生素D3[1,25-(OH)2D31具有潜在抗肿瘤效应.目的:观察丁酸钠和1,25-(OH)2D3对人结肠癌细胞增殖的影响及其可能机制.方法:以不同浓度丁酸钠(0.5～2.0 mmol/L)、1,25-(OH)2D3(10-8～10-6mol/L)或两者联合[1.0 mmol/L丁酸钠+10-7mol/L 1,25-(OH)2D3]诱导人结肠癌细胞株HT29,MTT法检测细胞生长抑制率,流式细胞术检测细胞周期和细胞凋亡,RT-PCR检测hTERT mRNA表达.结果:丁酸钠和1,25-(OH)2D3能剂量和时间依赖性地抑制HT29细胞生长;1.0 mmol/L丁酸钠和10-7mol.L 1,25-(OH)2D3能诱导HT29细胞G0/G1期阻滞和细胞凋亡,抑制hTERT mRNA表达.联合用药组的上述作用较两者单用更为明显(P＜0.05).结论:丁酸钠和1,25-(OH)2D3抑制人结肠癌细胞增殖的作用与其通过下调hTERT基因表达而抑制端粒酶活性、阻滞细胞周期、诱导细胞凋亡有关:两者联合可产生协同作用.