无血清培养CD133^+Colo205大肠癌细胞可高表达ALDH1

CD133^+ Colo205 colorectal cancer cells express high levels of ALDH1 in serum-free culture

目的通过观察含生长因子的无血清培养基(serum-free medium,SFM)培养的Colo205细胞,研究其对CD133与ALDH1表达的影响。方法用含生长因子的无血清培养基对Colo205细胞进行培养,以含血清培养基(serum-supplimented medium,SSM)组作为对照,流式细胞术检测两组细胞表面标志物CD133表达的阳性率;流式分选SFM组CD133+细胞和CD133-细胞,倒置显微镜观察CD133+细胞和CD133-细胞在无血清培养基中的生长特性;利用细胞免疫荧光检测CD133+细胞和CD133-细胞CD133和ALDH1的表达;分别将CD133+细胞和CD133-细胞在NOD/SCID小鼠皮下进行成瘤实验,采用免疫组织化学方法对肿瘤组织检测ALDH1表达。结果 SFM组CD133+细胞比例明显高于SSM组(P<0.05);CD133+细胞在SFM中可以形成肿瘤干细胞球,而CD133-则不能形成;CD133+细胞高表达CD133和ALDH1,且两者共表达,而CD133-细胞则是阴性表达;CD133+细胞和CD133-细胞成瘤后,CD133+细胞组肿瘤组织ALDH1阳性表达,而CD133-细胞组阴性表达。结论含生长因子的无血清培养基培养CD133+Colo205大肠癌细胞能够形成肿瘤干细胞球及高表达ALDH1,ALDH1可能是大肠癌干细胞候选的标志物之一。

Objective To investigate the expression pattern of CD133 and ALDH1 in colorectal cancer cells line Colo205 cultured in serum-free medium （SFM） containing recombinant human epidermal growth factor （EGF） and basic fibroblast growth factor （bFGF）. Methods Colo205 cells were cultured in serum-free medium （SFM） containing human recombinant EGF and bFGF or in serum-supplemented medium （SSM）. The expression of CD133 was analyzed in both groups, and CD133~ and CD133- cells sorted from the SFM group using flow cytometry and observed microscopically for their growth status. The expression of CD133 and ALDH1 in CD133＂ cells and CD133- cells was detected by immunofluorescence assay. CD133＇ cells and CD133~ cells were then injected subcutaneously into NOD/SCID mice and the expression of ALDH1 in the tumor tissues was detected by try. Results The cells in SFM group showed a significantly higher percentage of CD133~ ceils than those in SSM group （P〈0.05）. In SFM, CD133＂ cells were capable of forming tumor spheres while CD133- cells could not; CD133~cells strongly expressed CD133 and ALDH1 and CD133- cells did not. In mice, tumors generated by CD133~ cells, but not by CD133- ceils, positively expressed ALDH1. Condusion CD133~ Colo205 colorectal cancer cells in SFM containing human recombinant EGF and bFGF can form tumor spheres and strongly express ALDH1. ALDH1 may be one of the candidate markers of colorectal cancer stem cells.