目的：探讨microRNA-200c（miRNA-200c）在胰腺癌干细胞中的表达及作用。 方法：应用流式细胞术在人胰腺癌PANC-1 细胞中以CD24+CD44+ESA+ 为标记物分选胰腺癌干细胞， 并通过NOD/SCID 小鼠移植瘤实验验证其肿瘤干细胞特性； 分别用RFQ-PCR 法Transwell 试验检 测PANC-1 细胞、胰腺癌干细胞以及转染miRNA-200c 前体片段或阴性对照序列的胰腺癌干细胞的 miRNA-200c 表达与侵袭能力。 结果：PANC-1 细胞中分选出CD24+CD44+ESA+ 细胞（ 占0.8%） 具有肿瘤干细胞特性， 其在小鼠皮 下移植后的移植瘤体积明显大于同期移植的PANC-1 细胞[（1 725.14±261.29）mm3 vs.（479.65± 99.67）mm3，P<0.05]； 胰腺癌干细胞中miRNA-200c 的表达量明显低于PANC-1 细胞（0.15±0.01 vs. 1.00±0.09，P<0.05），平均穿膜细胞数明显多于PANC-1 细胞[（321±7.62）个vs.（70±16.47）个， P<0.05]，但转染miRNA-200c 前体片段后，胰腺癌干细胞中miRNA-200c 表达量明显升高，平均穿膜细 胞数明显减少（P<0.05）。 结论：胰腺癌干细胞中miRNA-200c 的表达降低，miRNA-200c 具有抑制胰腺癌干细胞生长及侵袭力 的作用。
Expression of microRNA-200c in pancreatic cancer stem cells and its significance
Objective: To investigate the expression and action of microRNA-200c (miRNA-200c) in pancreatic cancer stem cells. Methods: Pancreatic cancer stem cells were sorted from human pancreatic cancer PANC-1 cells by FACS using CD24+CD44+ESA+ as marker, and their stem cell properties were assessed by xenograft tumor assay in NOD/ SCID mice. The miRNA-200c expression and invasion ability in PANC-1 cells, pancreatic cancer stem cells and pancreatic cancer stem cells transfected with miRNA-200c precursor sequence or negative control sequence were determined by RFQ-PCR method and Transwell invasion assay, respectively. Results: The CD24+CD44+ESA+cells (accounting for 0.8%) sorted from PANC-1 cells presented tumor stem cell properties, and the volume of the xenograft tumor after their subcutaneous transplantation in mice was significantly larger than that after PANC-1 cells transplanted at the same time [(1 725.14±261.29) mm3 vs. (479.65±99.67) mm3, P<0.05]. In pancreatic cancer stem cells compared with PANC-1 cells, the miRNA- 200c expression level was significantly decreased (0.15±0.01 vs. 1.00±0.09, P<0.05), and transmembrane cell number was significantly increased (321±7.62 vs. 70±16.47, P<0.05), but the miRNA-200c expression level was significantly increased and transmembrane cell number was significantly decreased in pancreatic cancer stem cells after transfection with miRNA-200c precursor sequence (both P<0.05). Conclusion: MiRNA-200c expression is reduced in pancreatic cancer stem cells, and miRNA-200c has inhibitory effect on growth and invasiveness of pancreatic cancer stem cells.