RESUMO
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