中文摘要：

目的从人肺癌细胞系A549中分离并鉴定肺癌干细胞。方法将A549细胞置于无血清条件培养基中培养,形成细胞球,采用平皿克隆形成实验、MTT细胞增殖实验、RT-PCR、Western blot、免疫荧光技术,检测并比较A549细胞和A549细胞球的增殖能力及干细胞相关标记的表达水平,鉴定细胞球的肿瘤干细胞特性。结果利用无血清条件培养基从A549细胞中分离出肿瘤干细胞样细胞;相比A549细胞,细胞球呈悬浮生长,增殖能力和克隆形成数目（104±7）高于贴壁细胞[（37±3）（P〈0.05）],且干细胞相关标记Sox2（2.68±0.39）和Oct4（1.23±0.12）表达水平明显提高[贴壁细胞Sox2（0.05±0.02）、Oct4（0.10±0.02）,P〈0.05]。结论运用无血清条件培养基可以从A549细胞系中有效富集肺癌干细胞样细胞。

英文摘要：

Objective To isolate and identify the lung cancer stem like cells from the established human lung adenocarcinoma cell line A549.Methods The A549 cells were cultured in serum-free condition medium to form tumor spheres.Colony formation assay and MTT assay were used to observe the colony formation ability.RT-PCR,Western blot analysis,and immunofluorescent staining were performed to compare the expression levels of stem cell markers between A549 cells and A549 tumor sphere cells.Results The stem like cells were isolated from A549 cells in serum-free condition medium and formed typical neurospheres.The results showed that the proliferation and self-renewal capacity of the A549 sphere cells were stronger than A549 cells.A549 sphere cells expressed higher levels of stem cell markers Sox2 and Oct4 than A549 adhere cells（2.68±0.39 vs 0.05±0.02,1.23±0.12 vs 0.10±0.02,P〈0.05）.Conclusion The serum-free condition culture effectively enrich cancer stem like cells from human lung adenocarcinoma cell line A549.