【摘要】 背景与目的已有的研究提示肺腺癌源自肺脏细支气管肺泡干细胞(BASC)的恶性转化,但该假说在人体中尚未得到证实。本研究旨在对人肺腺癌干细胞的BASC特征进行分析。方法人肺腺癌干细胞经流式细胞纯化或无血清悬浮培养获得,所得细胞采用免疫荧光检测BASC特征性标志并经尾静脉注射至免疫缺陷小鼠观察肿瘤转移。结果人肺腺癌细胞A549和SPC-A1均表达Ⅱ型肺泡细胞标志SP-C,但少数细胞表达支气管非纤毛柱状细胞标志CCSP和胚胎干细胞基因OCT4,提示此类细胞属于BASC样癌干细胞。采用流式细胞分选技术纯化其中的CD24+CD22+肺腺癌干细胞后,发现此类细胞属于CCSP+SP-C+OCT4+细胞,其表型与BASC相同。此外,肺腺癌细胞在无血清培养条件下经EGF/IGF-1/FGF-10刺激能够形成悬浮生长的球体,这类肺球体细胞的特征也与BASC相同。肺球体细胞在含血清条件下培养2周即发生分化,表现为CCSP和OCT4表达丢失。动物实验揭示肺球体细胞具有高转移能力。结论人肺腺癌干细胞具有BASC特征并表达胚胎干细胞基因OCT4,此类肺癌细胞可能与小鼠肺腺癌一样,源自肺脏BASC的恶性转化。更多还原

【Abstract】 Background and objective Lung adenocarcinomas are proposed to originate from the malignant transformation of bronchioalveolar stem cells(BASC).This hypothesis,however,has not been confirmed in humans yet.In the present study,we determined to analyze the BASC properties in human lung adenocarcinoma stem cells.Methods The human lung adenocarcinoma stem cells were obtained by flow cytometry(FCM) and induced with the sphere-forming assay.The markers associated with BASC were measured by immunofluorescent staining,and their metastatic capacity was evaluated by injecting into NOD/SCID mice via tail vein.Results The majority of A549 and SPC-A1 human lung adenocarcinoma cells expressed the type Ⅱ alveolar cell-specific marker SP-C.However,a minority of cells also expressed the bronchiolar Clara cell-specific marker CCSP and the embryonic stem cell marker OCT4,suggesting that these cells may belong to cancer stem cells with BASC properties.The CD24+CD221+ human lung adenocarcinoma stem cells were purified by FCM and then subjected to the immunofluorescent staining.The results documented that these cells had the phenotype of CCSP+SP-C+OCT4+,with the same phenotype as mouse BASC.Furthermore,the float-growing spheres(named pulmospheres) were developed after 2-week incubation of cancer cells in the serum-free medium containing EGF,IGF-1,and FGF-10.Again,the resultant pulmosphere cells had the phenotype of BASC.These cells were able to differentiate when incubated for two weeks in serum-containing conditions,exhibiting the loss of CCSP and OCT4 markers.Animal studies indicated that the pulmosphere cells had the highly metastatic capacity.Conclusion The human lung adenocarcinoma stem cells may originate from the transformation of BASC,as their mouse counterparts.These primitive cancer cells are characterized to express the BASC markers as well as the embryonic stem cell gene OCT4.更多还原