BMI-1通过激活PI3K/Akt信号通路促进裸鼠体内淋巴瘤生长的机制研究

目的:探讨原癌基因BMI-1对裸鼠体内淋巴瘤生长的影响及潜在分子机制。方法:培养鼠源淋巴瘤细胞FOX-NY，并对细胞进行BMI-1沉默和过表达处理，以及联合PI3K/Akt抑制剂处理。CCK-8法检测各组细胞增殖情况。通过腋窝下接种鼠源淋巴瘤细胞FOX-NY、沉默BMI-1的FOX-NY(BMI-1--FOX-NY)、过表达BMI-1的FOX-NY(BMI-1+-FOX-NY)建立裸鼠淋巴瘤动物模型。裸鼠分为:对照组、质粒空载组、BMI-1--FOX-NY组、BMI-1+-FOX-NY组。对裸鼠体重、肿瘤体积和质量等指标进行检测。采用PCR技术测定裸鼠体内BMI-1 mRNA表达。采用苏木精-伊红(HE)染色观察肿瘤组织病理学情况。采用免疫组化染色和蛋白印迹检测裸鼠瘤体BMI-1、p-PI3K、p-Akt蛋白表达。结果:和空载组相比，BMI-1-组细胞增殖能力显著降低，BMI-1+组细胞增殖能力显著升高。和BMI-1+组细胞相比，BMI-1+-Miltefosine组细胞增殖能力显著降低。与空载组比较，BMI-1--FOX-NY组裸鼠体重显著降低(P＜0.001)、肿瘤体积显著减小(P＜0.001)、肿瘤组织病理学显著改善，瘤体BMI-1 mRNA水平显著降低(P＜0.001)、瘤体BMI-1、p-PI3K、p-Akt蛋白水平显著降低(P＜0.001)。反之，BMI-1+-FOX-NY组裸鼠体重显著增加(P＜0.01)、肿瘤体积显著增加(P＜0.01，P＜0.001)、肿瘤组织病理学显著恶化，瘤体BMI-1 mRNA水平显著升高(P＜0.001)、瘤体BMI-1、p-PI3K、p-Akt蛋白水平显著升高(P＜0.01，P＜0.001)。结论:BMI-1在淋巴瘤组织中表达显著升高，BMI-1可以促进DLBCL的生长并激活PI3K/Akt信号通路。

The study of the mechanism of BMI-1 promoting the lymphoma growth in nude mice via activating PI3K/Akt signaling pathway

Objective:To explore the effect of proto-oncogene BMI-1 on lymphoma growth in nude mice and the potential molecular mechanism.Methods:The murine lymphoma cells FOX-NY were cultured and treated with BMI-1 silencing and overexpression,and combined with PI3K/Akt inhibitor.Cell proliferation was detected by CCK-8 method.Animal models of lymphoma in nude mice were established by axillary inoculation of murine lymphoma FOX-NY,silent BMI-1 FOX-NY (BMI-1--FOX-NY) and overexpressed BMI-1 FOX-NY(BMI-1+-FOX-NY) cells.The nude mice were divided into control group,plasmid no-load group,BMI-1--FOX-NY group and BMI-1+-FOX-NY group.The body weight,tumor volume and tumor mass of nude mice were detected.The expression of BMI-1 mRNA in nude mice was determined by PCR.The histopathology of tumor tissues was observed using with hematoxylin-eosin staining.The expressions of BMI-1,p-PI3K and p-Akt protein in nude mice were detected by immunohistochemistry and western blot.Results:Compared with the empty plasmid group,the proliferation ability of cells in the BMI-1- group was significantly decreased,and the proliferation ability of cells in the BMI-1+ group was significantly increased.Compared with the cells in the BMI-1+ group,the proliferation ability of the cells in the BMI-1+-Miltefosine group was significantly decreased.Compared with the empty plasmid group,the weight of nude mice in BMI-1--FOX-NY group was significantly reduced (P＜0.001),the tumor volume was obviously reduced (P＜0.001),the tumor histopathology was remarkally improved,the BMI-1 mRNA level,the BMI-1,p-PI3K and p-Akt protein levels were significantly reduced (P＜0.001).On the contrary,in BMI-1+-FOX-NY group,the weight of nude mice increased significantly (P＜0.01),the tumor volume increased prominently (P＜0.01,P＜0.001),the tumor histopathology deteriorated significantly,the BMI-1 mRNA level (P＜0.001),the BMI-1,p-PI3K,p-Akt protein level increased largely (P＜0.01,P＜0.001).Conclusion:BMI-1 expression is significantly increased in lymphoma,BMI-1 can promote the growth of DLBCL and activate the PI3K/Akt signaling pathway.