不同氧环境下胶质瘤干细胞源性外泌体携带miRNAs对肿瘤增殖作用的研究

Effects of glioma stem cell-derived exosomal microRNAs in different oxygen environments on the tumor proliferation

目的探讨不同氧环境下胶质瘤干细胞（GSCs）源性外泌体携带miRNAs对肿瘤增殖的作用。方法在低氧（1％O2）及常氧（21％O2）条件下培养U87MG—GSCs，差速离心分离获得外泌体。将外泌体与U87MG胶质瘤细胞及人脑微血管内皮细胞（HBMECs）共培养，CCK-8法测定细胞的增殖活性。Affymetrix微阵列分析低氧及常氧条件下U87MG—GSCs源性外泌体携带miRNAs的差异表达情况。结果（1）低氧及常氧条件下GSCs源性外泌体的数量及大小相似。外泌体的平均直径为（43．0±20．3）nm（范围为25—65nm）；（2）比较低氧及常氧U87MG—GSCs源性外泌体携带的nfiRNAs，发现两者共表达152种miRNAs，包括91种上调的miRNAs及61种下调的miRNAs；（3）低氧条件下U87MG-GSCs源性外泌体与U87MG胶质瘤细胞及HBMECs共培养，能显著增加细胞活性（均P〈0．05）。结论GSCs源性外泌体介导miRNA的转运，从而发挥介导促血管内皮细胞增殖及促进胶质瘤细胞增殖的作用。在肿瘤增殖过程中外泌体介导的细胞间信号通路可能成为一个潜在的治疗靶点。

Objective To explore the effect of exosolnes derived from glioma stern cells （GSCs） cultured in different oxygen environments carrying miRNAs on the tumor proliferation. Methods The exosomes derived from U87MG-GSCs cultured under hypoxic（ 1% 02 ） and normoxic（21% 02） conditions were isolated by differential centrifugation. Exosomes were co-cultured with U87MG glioblastoma cells and human brain microvascular endothelial cells （HBMECs） , and cell viabilities were determined using the cell counting kit-8 （ CCK-8 ） assay. The microRNA content of exosomes produced by hypoxic and normoxic U87MG-GSCs were analyzed by Affymetrix microarrays. Results The count and diameter of GSC-derived exosomes under hypoxic and normoxic conditions were similar. The average diameter of exosomes was （43.0±20.3） nm （ range ： 25 - 65 nm）. The U87MG-GSCs under hypoxic and normoxic conditions had in common a total of 152 exosomal miRNAs including 91 miRNAs with up-regulation and 61 miRNAs with down-regulation. Exosomes derived from hypoxic U87MG-GSCs were co-cultured with U87MG and HBMECs, which caused a significant increase in cell viability （ all P 〈 0. 05 ）. Conclusions It is suggested that GSC-derived exosome-mediated miRNA transduction plays an important role in facilitating the proliferation of epithelial and glioma ceils. The exosome-involving intercellular signal pathway during tumor proliferation might become a potential treatment target.