NK4竞争性阻断肝细胞生长因子／Met途径抑制人Raji淋巴瘤移植瘤的增殖效应

NK4 growth inhibition of human Raji lymphoma xenografts by competitive interrupting HGF/Met signal pathway

目的观察NK4对裸鼠人Raji淋巴瘤移植瘤增殖的抑制作用，探讨其分子机制。方法构建肝细胞生长因子（HGF）基因转染的裸鼠人Raji淋巴瘤移植瘤模型。成瘤后经尾静脉连续4周注射NK4蛋白（每只50μg／a），动态监测裸鼠体质量和瘤体生长。8周后取瘤组织，采用即时荧光定量PCR检测移植瘤HGFmRNA、c—MetmRNA的表达，分别采用末端转移酶标记技术（TUNEL法）和免疫组织化学检测移植瘤组织的凋亡系数（AI）和微血管密度（MVD），进行综合分析。结果成功构建裸鼠移植瘤模型。各组裸鼠体质量均下降，以NK4蛋白组最大，但组间差异无统计学意义（P〉0．05）。HGF基因转染组瘤体积大于对照组（P＜0．01），对照组间差异无统计学意义（P＞0．05），注射NK4蛋白后瘤体积均明显减小（P〈0．01）。注射NK4蛋白后，HGF基因转染组HGFmRNA、c-MetmRNA表达增强（P＜0．01）。HGF基因转染组AI（33．5％±12．3％）显著低于对照组（89．1％±22．3％，81．9％±27．O％，P＜0．05），但NK4蛋白注射后增加明显（119．1％±18．9％，P＜0．01）。HGF基因转染组MVD（28．5±2．0）较对照组（12．2±1．4，13．84-1．3，P＜0．01）为高，但NK4蛋白注射后MVD降低（15．54±2．5，P＜0．01）。结论NK4可显著抑制HGF基因转染的裸鼠人Raji淋巴瘤移植瘤的生长，其可能经竞争性阻断HGF／Met信号转导途径而促进肿瘤细胞凋亡并抑制瘤内血管新生而发挥其效应。

Objective To observe the inhibition of NK4 protein in the proliferation of human Raji lymphoma xenografts in nude mice, and to explore its molecular mechanism. Methods Models of human Raji lymphoma xenograft transfected with HGF gene were established by subcutaneous inoculation in nude mice. After establishment of the models, the mice received continuous NK4 protein via tail vein for 4 weeks, and the weight and tumor growth were monitored every week. After 8 weeks, the expression of HGF mRNA and c-Met mRNA of tumor tissues was measured by real-time fluorescent quantitation PCR. The apoptotic index （AI） and microvessel density （MVD） were evaluated by terminal deoxynucleotidyl transferase- mediated nick end labeling （TUNEL） and immunohistochemistry, respectively. Results The models of human Raji lymphoma xenograft were successfully established. Although the animal weights of all groups declined, especially in the groups with NK4 protein injection, there was no statistical significance （P 〉0. 05）. The tumor volume in HGF gene transfected group was larger than those of the control groups （P 〈0. 01 ）, and there was no statistical significance among the control groups （P 〉0. 05）. However, the tumor volume of the NK4 protein injection group decreased significantly （P 〈0.01 ）. Expression of HGF mRNA and c-Met mRNA in HGF gene transfected group increased significantly after injection of NK4 protein （ P 〈O. 01 ）. AI in HGF gene transfected group （33.5% ±12. 3% ） was significantly lower than that of control groups （89. 1% ±22. 3% vs. 81.9% ±27.0% , P 〈0. 05）, but became significantly higher （ 119. 1% ±18.9% ） after NK4 protein injection （ P 〈0.01 ）. MVD in HGF gene transfected group （ 28.5 ±2.0） was higher than that of control groups （ 12. 2 ±1.4, 13.8±1.3, P 〈0.01 ）, although declined （ 15.5±2. 5 ） after NK4 protein injection （ P 〈0.01 ）. Conclusions NK4 protein suppresses significantly the growth of human Raji lymphoma xenografts transfected with HGF gene. The pathogenesis may be involved in promoting tumor cell apoptosis and restraining tumor angiogenesis through competitive interrupting HGF/Met signal pathway.