三氧化二砷对人大肠癌细胞端粒酶活性及细胞凋亡的影响

目的：探讨三氧化二砷（As₂O₃）对人大肠癌细胞株 CCL-187 端粒酶活性及细胞凋亡的影响。方法：CCL-187 细胞分为对照组、1.0 μmol•L^-1As₂O₃ 组和 2.5 μmol•L^-1As₂O₃ 组，共同孵育1～6 d。MTT 法计算细胞生长抑制率，电镜下观察细胞形态学变化，RT-PCR 法检测细胞端粒酶 hTERT-mRNA 的表达，TRAP-PCR-ELISA 法检测细胞端粒酶活性。结果：1.0 μmol•L^-1 As₂O₃ 组细胞分化明显，2.5 μmol•L^-1As₂O₃ 组出现细胞凋亡。同时2组端粒酶 hTERT-mRNA 的表达均下调，端粒酶活性降低，且具有时间依赖性，与对照组比较差异有显著性（P<0.01 或 P<0.05）；2.5 μmol•L^-1 As₂O₃ 组与 1.0 μmol•L^-1 As₂O₃ 组比较差异也有显著性（P<0.01）。细胞生长抑制率与细胞端粒酶 hTERT-mRNA 的表达呈负相关（1.0 μmol•L^-1 As₂O₃ 组 r=－0.803，P<0.01；2.5 μmol•L^-1 As₂O₃ 组 r=－0.697，P<0.01），与端粒酶活性的下调呈负相关（1.0 μmol•L^-1 As₂O₃ 组 r=－0.836，P<0.01；2.5 μmol•L^-1 As₂O₃ 组 r=－0.792，P<0.01）；细胞端粒酶 hTERT-mRNA 的表达与细胞端粒酶活性呈正相关（1.0 μmol•L^-1 As₂O₃ 组 r=0.956，P<0.01；2.5 μmol•L^-1 As₂O₃ 组 r=0.988，P<0.01）。结论：As₂O₃ 对 CCL-187 细胞有促进分化及诱导凋亡的作用，其机制可能是下调细胞端粒酶 hTERT-mRNA 的基因表达，从而抑制端粒酶的活性。

Effect of arsenic trioxide on telomerase activity and apoptosis of human colon cancer cell Line

Objective Abstract:Objective To explore the effects of arsernic trioxide(As2O3) on telomerase activity and cellular apoptosis of human colon cancer cell line CCL-187.Methods CCL-187 cells were divided into control group,1.0 μmol·L-1As2O3 group and 2.5 μmol·L-1As2O3 group,all groups were cultivated for 1 to 6 d.The inhitory rate of cell growth was detected by MTT assay.The morphologic changes of CCL-187 cells were observed under electron microscope.The expression of hTERT at mRNA level was analyzed by RT-PCR.Telomerase activity was determined by TRAP-PCR-ELISA.Results The differentiation of cells was found in 1.0 μmol·L-1 As2O3 group,but apoptosis in 2.5 μmol·L-1 As2O3 group,and at the same time,the telomerase activity was reduced and the hTERT-mRNA expression was downregulate in 1.0 μmol·L-1 As2O3 group and 2.5 μmol·L-1 As2O3 group in a time-dependent manner.There were significant differences compated with control group(P<0.01 or P<0.01);there were also significant differences between 2.5 μmol·L-1 As2O3 group and 1.0 μmol·L-1 As2O3 group(P<0.01).The inhibitory rate of cell growth was closely negatively correlated with the downregulation of hTERT-mRNA(1.0 μmol·L-1 As2O3 group,r=-0.803,P<0.01;2.5 μmol·L-1 As2O3 group,r=-0.697,P<0.01) and the reduction of telomerase activity(1.0 μmol·L-1 As2O3 group,r=-0.836,P<0.01;2.5 μmol·L-1 As2O3 group,r=-0.792,P<0.01).The reduction of telomerase activity was closely correlated with the downregulation of the hTERT-mRNA(1.0 μmol·L-1 As2O3 group,r=0.956,P<0.01;2.5 μmol·L-1 As2O3 group,r=0.988,P<0.01).Conclusion As2O3 can induce differentiation and apoptosis of CCL-187 cells.Its mechnism may be ralated to reducting the telomerase activity through downregulation of the hTERT-mRNA expression.