摘 要 目的: 探索人黑素瘤分化相关基因-7（melanoma differentiation associated gene7，mda7；又称IL-24）对慢性粒细胞白血病K562细胞的抑制作用。方法：用RTPCR法检测11个造血系统恶性肿瘤细胞系mda-7受体的转录情况。用脂质体转染法将构建的重组真核表达载体pTargetIL24转染K562细胞。以RTPCR和Western blotting方法检测转染的K562细胞mda7的表达情况；通过MTT法、集落形成实验、流式细胞术、AnnexinⅤ/PI检测mda7/IL24对K562细胞增殖、集落形成、细胞周期和凋亡的影响；以裸鼠移植瘤模型观察mda-7对K562细胞移植瘤的治疗作用。结果：在11个造血系统恶性肿瘤细胞系（NB4、HL60、CEM、Namalwa、Jurkat、KG1a、U937、K562、Ramos、J61、HEL细胞）中没有检测到完整mda7受体的表达。转染mda7的K562细胞能显著表达mda-7mRNA及其蛋白；其与转染空载体和未转染的K562细胞相比，细胞增殖活力以及集落形成能力明显下降（P＜0.05），细胞周期阻滞于G0/G1期（P＜0.05），但细胞凋亡率没有明显变化。裸鼠体内实验证实了mda7/IL24明显抑制K562细胞移植瘤生长（P＜0.01）。结论：mda-7/IL-24对白血病细胞系K562具有明显的体内外抑制作用，该作用与mda7/IL24引起细胞周期G0/G1期阻滞有关。

Abstract Objective: To explore the inhibitory effect of human melanoma differentiation associated gene7 (mda7/IL24) on chronic myelocytic leukemia cell line K562 in vitro and in vivo.Methods: The expression of mda7〖STBZ〗 receptor was examined in 11 malignant hematopoietic cell lines（NB4, HL60, CEM, Namalwa, Jurkat, KG1a, U937, K562, Ramos, J61, and HEL） by RTPCR. Then the constructed pTargetIL24 eukaryotic expression vector was transduced into K562 cells via Lipofectamine reagent. The expression of mda7 mRNA and protein was verified by RTPCR and Western blotting. MTT assay, colony forming assay, flow cytometry, AnnexinⅤ/PI and xenograft tumor models in nude mice were used to assess the effects of mda7 on tumor cells proliferation, colony forming, cell cycle, apoptosis, and tumorigenesis, respectively. Results: The expression of mda7 intact receptor was not detected in the 11 malignant hematopoietic cell lines. Significant expression of mda7 mRNA and protein was found in K562 cells stably transfected with mda7. Compared with control cells transfected with plasmid vector or untransfected cells, cells transfected with mda7had decreased tumor cells proliferation (P<0.05), inhibited colony formation (P<0.05), and more cells were arrested in G0/G1 stage (P<0.05). However, there was no significant difference in cells apoptosis between control cells and K562 cells transfected with mda7. Tumor xenograft models in BALB/c nude mice showed that mda7/IL24 significantly inhibited the growth of K562 transplantation tumor (P<0.01). Conclusion: Human mda7/IL24 can efficiently inhibit the proliferation of chronic myelocytic leukemia cell line K562 in vitro and in vivo, possibly by inducing K562 cell arrest in G0/G1 stage.

国家自然科学基金资助项目（No. 30672364, No.30872983）；天津市应用基础研究基金重点资助项目（No. 07JCZDJC07600）