中文摘要：

目的探索肺癌细胞分泌的Exosomes对其分泌细胞及其同源肿瘤细胞增殖的影响，以及PI3K/Akt和SRC信号通路在其中的作用。方法采用密度梯度离心法从肺癌A549细胞的上清液中提取Exosomes，透射电子显微镜法观察Exosomes的形态，Western blotting法检测Exosomes标志蛋白的表达，MTT法检测细胞的增殖能力。结果A549细胞来源的Exosomes的直径在30～100nm之间，由双层膜构成。Western blotting检测到Exosomes中CD9的表达，且A549细胞来源的Exosomes以剂量和时间依赖性的方式促进其自身及同源肿瘤细胞HCC827细胞的增殖，并伴随Akt和SRC的活化。结论肺癌A549细胞来源的Exosomes以时间和剂量依赖性促进其自身及同源肿瘤细胞的增殖，其机制可能与Akt和SRC的活化有关。

英文摘要：

Objective To explore the effect of Exosomes isolated from the A549 lung cancer cells on the proliferation of these cells and their ho- mologous tumor cells, HCC827, and the role of the PI3K/Akt and SRC signaling pathways in this process. Methods Exosomes were isolated from the supematant after density gradient centrifugation of A549 cells. The Exosomes morphology was observed by transmission electron microscopy. The expression of the Exosome-specific proteins was analyzed using Western blotting. Cell proliferation was investigated using the MTF assay. Results The A549-derived Exosomes were 30-100 nm in diameter and had a bilayer membrane.Western blotting showed that CD9 was detected in these Exosomes. The isolated Exosomes promoted the proliferation of the A549 and the HCC827 cells in a dose-and time-dependent manner, accompanied by the activation of Akt and SRC. Conclusion Exosomes isolated from A549 cells promote the proliferation of the secreting cells and the homologous tumor cells in a dose-and time-dependent manner. The mechanism may be related to the activation of Akt and SRC.