中文摘要：

目的：论证人前列腺癌（prostate cancer，PCa）细胞株中是否存在干细胞亚群。方法：分别用免疫表型法和侧群（side population，SP）细胞法从5种人PCa细胞株（Dul45、IA8、LNCaP、TSU—PrL和PC-3）中富集类干细胞，再应用软琼脂克隆形成试验初步验证类干细胞亚群的体外生长方式及成瘤能力。选择LNCaP源sP细胞（LNCaP／SP），依次采用免疫细胞化学技术、Transwell、MTT以及裸鼠致瘤试验，分别检测其干细胞标记物的表达情况、鉴定其体外增殖和侵袭能力以及动物体内的致瘤和转移潜能。结果：5种细胞株中均难以分选出免疫表型为CD133＋CD44＋的细胞亚群。除PC-3外，其余4株细胞可分选出呈现典型克隆性生长特点的SP细胞。体外克隆形成率在IA8、LNCaP和TSU-PrL源sP细胞与非侧群（non-side population，NSP）细胞间有显著性差异（P〈0．05）。与LNCaP／NSP相比，LNCaP／SP的体外增殖和侵袭能力显著增强，同时阳性表达整合素以、Nanog、CD44、OCT4以及ABCG2等5种干细胞标记物。而且，LNCaP／SP的皮下成瘤率、骨转移率及瘤体体积亦显著高于LNCaP／NSP（P〈0．01）。结论：SP分选法更适合富集人PCa细胞株中类干细胞，LNCaP／SP细胞是PCa细胞株LNCaP中的肿瘤干细胞（cancer stem cell，CSC）。

英文摘要：

Objective： To sort and identify side population （SP） cancer stem cells （CSC） in human prostate cancer （PCa） cell lines. Methods： Stem-like cells were isolated from five PCa cell lines Du145, IA8, LNCaP, TSU-Pr and PC-3 using FACS based on CD133＋ CD44＋ immunophenotype and SP in Hoeehst staining. The in vitro growth pattern and tumorigenicity of SP stem ceils were verified by soft agar colony-formation trial. LNCaP/SP ceils were selected for further identification of stem cell properties using immunostaining, proliferation and invasion assay. Eventually, tumorigenicity and metastasis ability of LNCaP/SP were confirmed by xenograft experiments. Results ： The percentages of CSCs of the CD133 ~ CD44 ~ immunophenotype were extremely low in the five PCa cell lines. On the contrary, the percentages of the isolated SP cells were significantly higher in Du145 （ [ 0.15 ± 0.02 ] % ）, IA8 （ [ 0.60±0.07 ] % ）, LNCaP （ [ 0.8 ± 0.1 ] % ） and TSU-PrL （ [ 2.0±0.4 ] % ）, but none was detected in PC-3. Besides, IA8/SP, LNCaP/SP and TSU-PrL/SP cells showed a significantly greater colony-forming efficiency than non-side population （NSP） cells （P 〈 0.05）. Compared with LNCaP/NSP cells, LNCaP/SP cells exhibited high expressions of integrin a2, Nanog, CD44, OCT4 and AB- CG2, remarkably enhanced invasive and proliferative potentials in vitro, and markedly increased tumorigenicity and metastasis （P 〈0.01 ）. Conclusion ： SP sorting is more suitable than CD133＋ CD44＋ selection for enriching CSCs from PCa cell lines, and LNCaP/ SP represents a typical CSC population.