结肠癌 COLO 耐药株的构建及其与肿瘤干细胞的关系

目的：构建结肠癌 COLO 耐药株，探索其功能特性及其与肿瘤干细胞的关系。方法通过逐渐递增化疗药5-氟尿嘧啶（5-FU）浓度的方法，构建了耐0．10μmol／ml 和0．20μmol／ml 5-FU 的结肠癌 COLO 耐药株各1株，分别命名为 COLO／5-FU-1、COLO／5-FU-2。从增殖能力、克隆形成能力、迁移和侵袭能力、微球体形成能力、干性基因的表达、交叉耐药等方面与亲本结肠癌细胞株 COLO 进行对比。结果在存活检测中，常规培养后第4天，结肠癌耐药株 COLO／5-FU-2、COLO／5-FU-1、亲本 COLO 细胞的 A 值分别为0．61±0．13、0．54±0．07、0．41±0．09，差异有统计学意义（F ＝63．43，P ＝0．033）。随着耐5-FU 药物浓度的增加，COLO 耐药株的克隆形成率逐渐增强，COLO／5-FU-2、COLO／5-FU-1、亲本 COLO的克隆形成率依次为（87．6±12．7）％、（65．3±9．7）％、（38．5±7．6）％，差异有统计学意义（F ＝33．64， P ＝0．017）。COLO／5-FU-2、COLO／5-FU-1、亲本 COLO 每高倍视野中迁移穿过基底膜的细胞数分别为（482±39）个、（434±45）个、（373±38）个，侵袭穿过基底膜的细胞数分别为（174±42）个、（112±31）个、（87±29）个，差异均有统计学意义（F ＝109．61，P ＝0．009；F ＝67．31，P ＝0．032）。与亲本结肠癌细胞株COLO 比较，耐药株表达更高的干性基因，差异有统计学意义（F ＝47．31，P ＝0．042）；且耐药株对其他化疗药如米托蒽醌存在交叉耐药[如给药96 h，米拖蒽醌对亲本 COLO 的抑制率高于 COLO／5-FU-1、COLO／5-FU-2（0．749±0．042、0．423±0．024、0．342±0．018），差异有统计学意义（F ＝12．61，P ＝0．028）]。COLO／5-FU-2、COLO／5-FU-1、亲本 COLO 细胞的微球体形成率依次为（8．90±0．97）％、（6．20±0．75）％、（3．90±0．32）％，差异有统计学意义（F ＝164．32，P ＝0．006）。结论结肠癌 COLO耐药株有肿瘤干细胞样细胞的特点，是富集了的肿瘤干细胞。

Construction of colonic cancer drug-resistant cell line COLO and its relationship with tumor stem cells

Objective To construct a colon cancer chemotherapy-resistant cell line COLO,and study its characteristics and its relationship with tumor stem cells.Methods We constructed two 5-fluorouraci (5-FU)-resistant colon cancer cell line COLO/5-FU-1 and COLO/5-FU-2, which were resistant to 0.1 0 μmol/ml and 0.20 μmol/ml 5-FU respectively through gradiently increased drug concentration.The cha-racteristics of 5-FU-resistant cell lines were compared with parental colon cancer cell line COLO related to proli-feration,colony forming ability,migration and invasion,sphere forming ability,expression of stemness genes and cross drug-resistance.Results In the cell viability assay,4 days after regular training,the absorbancy of colon cancer 5-FU-resistant cell lines COLO/5-FU-2,COLO/5-FU-1 and parental colon cancer cell line COLO were 0.61 ±0.1 3,0.54 ±0.07 and 0.41 ±0.09 respectively,with significant difference (F =63.43,P =0.033).With the increased concentration of 5-FU,5-FU-resistant cell lines presented increasing clonality. The cloning efficiency of COLO/5-FU-2,COLO/5-FU-1 and parental colon cancer cell line COLO were (87.6 ±1 2.7)%,(65.3 ±9.7)% and (38.5 ±7.6)% respectively,with significant difference (F =33.64, P =0.01 7).In each high power field of vision,the cell numbers of migration through the basement membrane of COLO/5-FU-2,COLO/5-FU-1 and parental colon cancer cell line COLO were 482 ±39,434 ±45 and 373 ±38 respectively;and the cell numbers of invasion through the basement membrane were 1 74 ±42,1 1 2 ± 31 and 87 ±29 respectively,with significant differences (F =1 09.61 ,P =0.009;F =67.31 ,P =0.032). Compared with parental colon cancer cell line COLO,5-FU-resistant cell lines had higher expression of stem-ness genes (F =47.31 ,P =0.042).5-FU-resistant cell lines were cross-resistant to other chemotherapeutic drugs such as mitoxantrone.For example,after incubation for 96 hours,inhibition rate of mitoxantrone to parent colon cancer cell line COLO was higher significantly than COLO/5-FU-1 and COLO/5-FU-2 (0.749 ± 0.042,0.423 ±0.024,0.342 ±0.01 8),with significant difference (F =1 2.61 ,P =0.028).The micro-sphere forming rates of COLO/5-FU-2,COLO/5-FU-1 and parental colon cancer cell line COLO were (8.90 ± 0.97)%,(6.20 ±0.75)% and (3.90 ±0.32)% respectively,with significant difference (F =1 64.32,P =0.006).Conclusion Colon cancer drug-resistant cell line COLO possess tumor stem cell-like characteristics, which are enriched in cancer stem cells.