【摘要】 γ-射线可诱导人髓性白血病细胞株HL-60细胞凋亡,但其机制尚未完全明了。为了观察caspase-3在这种细胞凋亡模型中的作用,本研究设计合成针对caspase-3mRNA5′-非编码区和编码起始区的反义寡核苷酸(ASODNs),即ASODN-1和ASODN-2,以脂质体介导法将不同浓度ASODN-1和ASODN-2转染进入HL-60细胞,γ-射线照射。应用TUNEL法观察凋亡细胞形态学变化及检测凋亡细胞百分率,免疫细胞化学、Westernblotting和RT-PCR技术分别检测caspase-3及其mRNA在引入ASODNs前后的表达水平,并以错配寡核苷酸(MODN)转染及未转染细胞作为对照组。TUNEL法检测发现,当ASODN-1和ASODN-2转染终浓度≥3μmol/L时,γ-射线诱导的HL-60细胞凋亡率降低,与对照组相比均有显著性差异(P<0.01)。免疫细胞化学结果显示,与两对照组相比,转染ASODNs后各组caspase-3阳性细胞率显著下降,阳性细胞染色减弱,其平均灰度值显著增高(P<0.01)。Westernblotting检测显示,转染ASODNs组细胞caspase-3蛋白酶原表达降低,其中ASODN-1组显著低于ASODN-2组。RT-PCR结果显示两对照组细胞caspase-3mRNA均有明显表达,转染ASODNs后caspase-3mRNA表达丰度降低。另外,ASODN-1抑制细胞凋亡和caspase-3表达的作用显著强于ASODN-2(分别为P<0.05和P<0.01)。实验结果表明,caspase-3mRNAASODNs能够抑制γ-射线照射诱导的HL-60细胞凋亡,下调caspase-3蛋白和caspase-3mRNA的表达水平,其抑制作用在一定范围内呈剂量依赖性。更多还原

【Abstract】 It has been shown that γ-irradiation induces apoptosis of the human promyeloid leukemia cell line HL-60, but the mechanism remains unclear. To explore the effect of caspase-3 in this apoptotic model, antisense oligodeoxynucleotides (ASODNs) targeting 5′-noncoding region (ASODN-1) and initial translation region (ASODN-2) of caspase-3 mRNA were designed, synthesized and introduced into HL-60 cells by means of liposome-mediated transfection followed by γ-irradiation in the present study. The TUNEL assay was used for morphological analysis of HL-60 cell apoptosis. Immunocytochemical staining, Western blotting and RT-PCR were, respectively,performed for detecting expression of caspase-3 and its mRNA. HL-60 cells transfected with mismatched oligodeoxynucleotide (MODN) or untransfected were taken as the control groups. The TUNEL assay showed that the percentages of HL-60 cell apoptosis induced by γ-Irradiation in both ASODN-1 and ASODN-2 groups were significantly reduced compared with those in the control group (P<0.01) when the final transfection concentration was ≥3μmol/L. Immunocytochemistry demonstrated that in the ASODN-1 and ASODN-2 groups, caspase-3 positive cell percentages were reduced and average gray values of the positive cells increased significantly compared with those in the control group (P<0.01). Western blotting found that procaspase-3 expression in HL-60 cells of the ASODNs groups was decreased,and it was lower in the ASODN-1 group than in the ASODN-2 group. RT-PCR revealed marked expression of caspase-3 mRNA in HL-60 cells of the control group. Expression of caspase-3 mRNA was decreased after ASODNs transfection. Furthermore, ASODN-1 was more effective in inhibiting HL-60 cell apoptosis (P<0.05) and caspase-3 expression (P<0.01) than ASODN-2. These results indicate that caspase-3 mRNA ASODNs prevent HL-60 cells from apoptosis induced by γ-radiation,and reduce expression of caspase-3 and its mRNA. These effects are dose dependent in a certain range.更多还原