胃癌乳斑微转移在胃癌干细胞及前驱细胞研究中的意义

Significance of omental milky spots micrometastasis in screening gastric cancer stem cells and progenitor cells

目的:探讨胃癌乳斑微转移模型在胃癌干细胞及前驱细胞研究中的意义。方法:胃癌细胞系MFC,1×10~4细胞数量注射到小鼠腹腔内,72 h后取大网膜,收集乳斑微转移灶内的胃癌细胞团;以不同细胞数量进行NOD/SCID小鼠皮下注射,观察细胞的致瘤能力,移植瘤HE染色,免疫组化分析CEA、CK20表达;免疫细胞化学分析乳斑微转移灶内的胃癌细胞团干细胞相关标志物的表达。结果:皮下注射16周后,微转移灶内的胃癌细胞团组中,皮下注射数量为5×10~2个细胞有1个部位产生肿瘤组织:注射数量为1×10~3个细胞时,5个部位均能产生肿瘤组织。对照组皮下注射为5×10~4个细胞时,仅1个部位出现肿瘤,而注射部位全部出现肿瘤组织,需要5×10~6个以上的细胞数量。两组皮下肿瘤组织分别经HE染色和免疫组化分析CEA、CK20表达,与对照组比较无统计学差异。微转移灶内细胞团高表达CD133和CD44,而CD324的表达则明显下降。结论:胃癌乳斑微转移模型内存在丰富的胃癌于细胞及前驱细胞;大网膜乳斑微环境具有富集胃癌干细胞及前驱细胞的作用。CD133^+、CD44^+和CD324^-可能是胃癌干细胞的表面标志物。

Objective To investigate significance of omental milky spot micrometastasis model in screening cancer stem cells and progenitor cells.Methods 1×10~4 MFC cells were injected intraperitoneal.After 72 h of intraperitoneal injection,mice were sacrificed and the omentum was excised and the gastric cancer cells in micrometastasis were observed.The cells were suspended and injected subcutaneously into the right and left flanks of NOD/SCID mice with anesthesia.After 16 weeks all mice were sacrificed,and the tumors were removed and analyzed by histology（HE、CK20 and CEA）.The cells in the micrometastasis were collected and immunocytochemical staining of the cancer stem cells was carried out as markers related to CD133,CD44,CD24,CD34,and CD324.Results Of the 40 mice（dose range：1×10~1 to 1×10~3） injected with the gastric cancer cells in micrometastasis,one mouse transplanted with 5×10~2 cells generated a tumor, and tumors were consistently generated after injection of 1×10~3 cells.In contrast,one tumor was generated after the injection of 5×10~4 cells in the control group,and tumors were consistently generated after the injection of 5×10~6 cells.The histology of the tumors,as expressed by HE staining,showed the same poor differentiated adenocarcinomas.The immunohistochemical markers CK20 and CEA reveal similar staining patterns in both groups.Gastric cancer cells in the micrometastasis were high in expressing CD 133 and CD44,and low in expressing CD324.Conclusions Omental milky spots are a highly efficient＂natural filter＂for screening gastric cancer stem cells.Gastric cancer stem cells in the micrometastasis are high in expressing CD 133 and CD44,and low in expressing CD324.