人mda-7/IL-24对淋巴瘤细胞Namalwa的抑制作用

目的:研究黑素瘤分化相关基因-7(melanoma differentiation associated gene-7,mda-7,又称IL-24)对淋巴瘤细胞系Namalwa细胞的抑制作用。方法:用半定量RT-PCR方法检测10个造血系统恶性肿瘤细胞系(Namalwa、Raji、K562、NB4、U937、Ramous、CEM、KG1a、HL60、J6-1)中mda-7/IL-24的表达情况。用RT-PCR方法从活化的人外周血单个核细胞(PBMC)中克隆mda-7/IL-24编码区,构建真核表达载体pTarget-IL-24。经测序鉴定后,用脂质体法转染Namalwa细胞,筛选稳定表达细胞株。转染细胞经RT-PCR和Western blotting证实mda-7/IL-24的表达。通过MTF法、集落形成试验、流式细胞术、裸鼠体内成瘤实验来评价mda-7/IL-24对肿瘤细胞增殖、生长特性、集落形成、凋亡情况、体内致瘤能力的作用。结果:10个造血系统恶性肿瘤细胞系中未检测到mda-7/IL-24的表达;转染重组质粒pTarget-IL-24的Namalwa细胞在mRNA与蛋白水平都有mda-7/IL-24的表达;稳定表达mda-7/IL-24的Namalwa细胞增殖活力以及集落形成能力与转染空载体的对照组相比明显下降(P<0.05);但是两者的凋亡率比较无统计学意义。裸鼠体内移植瘤实验结果显示稳定表达mda-7/IL-24的Namalwa细胞株的致瘤性明显低于转染空载体的对照组(P<0.05)。结论:mda-7/IL-24对来源于Burkitt淋巴瘤的Namalwa细胞系具有明显的增殖抑制作用,为Burkitt淋巴瘤的基因治疗提供了新的思路。

Inhibitory effect of human mda-7/IL-24 on proliferation of lymphoma cell line Namalwa

Objective:To investigate the inhibitory effects of melanoma differentiation associated gene-7(mda-7/IL- 24)on lymphoma cell line Namalwa in vitro and in vivo.Methods:Using RT-PCR,the expression of mda-7/IL-24 was examined in 10 malignant hematopoietic cell lines,including Namalwa,Raji,K562,NB4,U937,Ramous,CEM,KG1a, HL60,J6-1,etc.The coding region of mda-7/IL-24 was cloned from LPS-treated human peripheral blood mononuclear cells(PBMC)by RT-PCR,and the eukaryotic expression vector pTarget-IL-24 was constructed.The recombinant vector, after sequenced,was transfected into Namalwa cell line via lipofectamine reagent.The stable expression transfectants were selected by G418.The expression of mda-7/IL-24 mRNA and protein was verified by RT-PCR and Western blotting.MTT assay,colony forming assay,apoptosis detection,and tumorigenesis in nude mice were used to assess the effects of mda- 7/IL-24 on tumor proliferation,growth characteristics,colony forming,apoptosis,and tumorigenesis.Results:Expression of mda-7/IL-24 mRNA was not found in any of the 10 malignant hematopoietic cell lines and the expression of mda-7/IL- 24 mRNA and protein was found in Namalwa cells transfected with recombinant plasmid pTarget-IL-24.Significant de- crease in tumor cell viability was observed in Namalwa cells stably transfected with mda-7/IL-24,compared with control cells transfected with empty plasmid pTarget(P<0.05).Transfection with mda-7/IL-24 also inhibited the colony forming ability of Namalwa cells(P<0.05).However,there was no significant change in the number of Annexin V-positive cells in mda-7/IL-24 transfected Namalwa cells compared with pTarget-transfected cells.The results of BALB/c nude mice transplantation experiment showed that Namalwa cells stably expressing mda-7/IL-24 had significantly lower tumorigenicity than those transfected with blank vectors(P<0.05).Conclusion:Human mda-7/IL-24 can efficiently inhibit the prolif- eration of lymphoma cell line Namalwa in vitro and in vivo,which provides a novel strategy for gene therapy of Burkitt lym- phoma.