胃癌细胞表面ALDH1表达及ALDH1^+细胞的“干性”鉴定

Expression of ALDH1 on surface of gastric cancer cells and identification of stem cell characteristics of ALDH1^+ cells

目的检测胃癌细胞系的乙醛脱氢酶1(ALDH1)表达,鉴定ALDH1^+细胞生物学特性。方法采用Aldefluor实验方法,通过流式细胞仪检测胃癌细胞系MGC-803、BGC-823及MKN-45中ALDH1的活性表达;选取MGC-803细胞系,分选出ALDH1^+和ALDH1^-细胞,进行分化潜能、平板克隆、耐药性、干性相关基因检测及裸鼠成瘤实验。结果MGC-803、BGC-823及MKN-45中ALDH1的表达比例为(13.00±1.34)%、(5.80±2.15)%及(36.5±5.4)%;分选出ALDH1^+、ALDH1^-细胞组,含血清培养1周后,ALDH1^+的表达比例为21.2%和3.9%,ALDH1^+细胞具有不对称分裂能力;ALDH1^+细胞组克隆形成率为(42.63±0.63)%,高于ALDH1^-细胞组(18.5±2.04)%,两组比较差异有统计学意义(P<0.05);相同氟尿嘧啶浓度下,ALDH1^+组生长抑制率均低于ALDH1^-组,差异有统计学意义(P<0.05);接种5×10~3个ALDH1^+及ALDH1^-细胞于小鼠皮下成瘤,与ALDH1^-细胞比较,ALDH1^+细胞成瘤率高。两组肿瘤体积比较差异有统计学意义(P<0.05)。结论胃癌细胞系普遍存在ALDH1的活性表达,ALDH1^+细胞具有干细胞生物学特性,可能提供胃癌新的诊断和治疗途径。

Objective To detect the expression of ALDH1 in gastric cancer cell lines and to identify the biological characteristics of ALDH1+cells.Methods Aldefluor assay was used to detect the expression of ALDH1 in gastric cancer cell lines MGC-803,BGC-823 and MKN-45 by flow cytometry.MGC-803 cell line was selected to isolate ALDH1+and ALDH1-cells,then the differentiation potential,plate cloning,drug resistance,stemness genes and tumorigenicity of the cells were studied.Results The positive expression ratio of ALDH1 in MGC-803,BGC-823 and MKN-45 cells was(13.00±1.34)%,(5.80±2.15)%and(36.50±5.40)%respectively.ALDH1+and ALDH1-cells were sorted and cultured for 1 week,the positive expression ratio of ALDH1 was 21.2%and 3.9%respectively.The colony formation rate was(42.63±0.63)%in the ALDH1+cell group,which was significantly higher than(18.50±2.04)%in the ALDH1-cell group(P<0.05).Under the same 5-FU concentration,the growth inhibition rate of the ALDH1+cell group was lower than that of ALDH1-cell group,the difference was statistically significant(P<0.05).With subcutaneous inoculation of 5×103 ALDH1+and ALDH1-cells in mice,ALDH1+cells had a higher rate of tumor formation than ALDH1-cells,the difference of the tumor volume between the two groups was statistically significant(P<0.05).Conclusions ALDH1 is actively expressed in gastric cancer cell lines.ALDH1+cells have stem cell properties,which may provide a new diagnostic and therapeutic approach for gastric cancer.