目的 探讨三磷酸腺苷结合转运体G2(ABCG2)与胰腺癌采用吉西他滨化疗抵抗的相互关系。方法 观察胰腺癌手术患者的癌和癌旁组织免疫组化及胰腺癌细胞系中ABCG2的表达,流式细胞术测定胰腺癌细胞系在吉西他滨刺激0、3、12、24、48、72 h后的ABCG2膜表达结果,选择高表达水平的PANC-1细胞株进行相关机制试验。观察吉西他滨作用0、15、30、45、120、180 min后P-AKT表达水平,及用PI3K/AKT抑制剂LY294002或AKT siRNA阻断AKT表达后ABCG2表达水平和生存率变化。免疫荧光共聚焦技术观察在对照、吉西他滨、LY294002和吉西他滨+LY294002 4种实验条件下细胞膜膜表面的ABCG2蛋白表达变化。结果 ABCG2蛋白表达量在胰腺癌组织中较癌旁组织明显增高,ABCG2+细胞在不同病理分化程度的胰腺癌细胞中均有表达。胰腺癌细胞系在吉西他滨刺激后总ABCG2水平无明显变化,而ABCG2+细胞数有明显增加。PANC-1在吉西他滨刺激后细胞总ABCG2蛋白表达无明显变化;p-AKT蛋白表达水平呈现增加趋势;ABCG2+细胞数明显增加,并呈时间相关性。LY294002或LY294002+吉西他滨处理细胞后ABCG2总蛋白表达无明显变化,siRNA-AKT2基因敲除或LY294002处理后,肿瘤细胞对吉西他滨的敏感性明显增加。免疫荧光共聚焦表明吉西他滨调节胰腺癌PI3K/AKT信号分子,介导ABCG2质膜移位。结论 吉西他滨活化PI3K/AKT信号分子,促进ABCG2质膜移位,抑制胰腺癌化疗敏感性。

Objective To investigate the relationship between ATP binding cassette transporter G2 (ABCG2) and gemcitabine chemotherapy resistance in pancreatic cancer. Methods The patient's pancreatic cancer surgery and adjacent tissues were observed by immunohistochemistry and pancreatic cancer cell lines' ABCG2 expression. Pancreatic cancer cell lines ABCG2 membrane expression results were observed by flow cytometry after gemcitabine stimulation (0, 3, 12, 24, 48, and 72 h). Then high expression levels of PANC-1 cell line were selected for mechanisms tests. P-AKT expression levels after gemcitabine action (0, 15, 30, 45, 120, and 180 min), and ABCG2 expression levels and the change of survival rate after blocking AKT expression with the PI3K/AKT inhibitor LY294002 or AKT siRNA were observed. Immunofluorescence confocal was used to observe ABCG2 protein in membrane surface expressions under four experimental conditions (control, gemcitabine, LY294002, gemcitabine + LY294002). Results Gemcitabine enhanced the expression of ABCG2's protein in cellular surface and ABCG2+ cells, which induced chemotherapy-resistance. Furthermore it was found that gemcitabine could regulate ABCG2 translocation of cytoplasm-membrane via activation of PI3K/Akt signaling pathway to mediate pancreatic cancer cells' chemoresistance. Conclusion Gemcitabine can activate PI3K/AKT signaling molecules, promote the shift of the ABCG2 plasma membrane, and restrain pancreatic cancer chemotherapy sensitivity.

天津市应用基础与前沿技术研究计划项目(13JCZDJC31300)