摘要
目的探讨甲基转移酶抑制剂5-氮杂-2′-脱氧胞苷(5-aza-2-′deoxycytidin,5-Aza-CdR)在小细胞肺癌中发挥抗瘤效应的可能性及可能机制。方法将5-Aza-CdR体外作用于人小细胞肺癌H446细胞,应用光镜、MTT法、流式细胞术、自发光荧光仪等方法观察H446细胞的形态学、增殖能力、细胞周期分布、药物敏感性、caspase-3/7活性及Rh123外排效率等的变化,同时应用甲基化敏感性随机引物PCR(MS-AP-PCR)法检测H446细胞基因组DNA甲基化水平。结果 5-Aza-CdR可明显降低H446细胞的基因组DNA甲基化水平,并抑制其细胞增殖。随着5-Aza-CdR处理时间延长,H446细胞中G1期细胞显著增多[由(56.3±2.5)升至(73.75±2.47),P<0.05],G2期细胞显著减少[由(19.1±6.8)降至(9.0±1.5)]。同时,H446细胞增殖能力较对照组显著降低(P<0.01),呈浓度依赖性,但对顺铂等化疗药物的敏感性无显著性差异(P>0.05)。此外,H446细胞的Rh123外排效率显著增加[由(11.5±2.3)升至(23.8±3.0),P<0.05],而caspase-3/7活性显著增强[由(257510.5±12861.5)升至(538585.5±10897.2),P<0.05]。结论 5-Aza-CdR在体外对人小细胞肺癌H446细胞具有较强的抗癌活性,低甲基化细胞毒作用(包括抑制细胞增殖、G1期阻滞、诱导细胞凋亡)以及恢复抑癌基因表达可能是其主要作用机制。
Objective As a reversible regulation progress,demethylation therapy has become the most promising strategy of tumor prevention and treatment.5-Aza-CdR has showed certainly antitumor activity in several tumors including non-small cell lung cancer,but its effect in small cell lung cancer needs further research.Methods After H446 cells treated with 5-Aza-CdR in vitro,the cell morphological changes was observed with light microscope.the proliferation ability and drug sensitivity were measured with MTT assay.The activity of caspase-3/7,efficacy of drug exclusion and cell cycle was assessed by luminometer and FACs.The genome DNA methylation status was examined by methylation-sensitive arbitrarily primed PCR（MS-AP-PCR）.Results H446 cells genome DNA methylation level apparently decreased after 5-Aza-CdR treatment.5-Aza-CdR could inhibit growth of H446 cells in the dose-dependent manner,induce the arrest of H446 cells in G1 phase（from 56.3±2.5 to 73.75±2.47,P〈0.05）,increase the caspase-3/7 activity（from 257510.5±12861.5 to 538585.5±10897.2） and efficacy of drug exclusion（from 11.5±2.3 to 23.8±3.0,P〈0.05）.Conclusion 5-Aza-CdR has a strong antitumor activity to H446 cells in vitro.The low methylation cytotoxic effect including cell growth-inhibit,G1 phase arrest and apoptosis and expression restoration of tumor suppressor gene might play an important role.
出处
《西部医学》
2010年第6期994-997,共4页
Medical Journal of West China
