胰腺星状细胞对胰腺癌细胞增殖能力的影响及机制

Effects and mechanisms of pancreatic stellate cells on proliferation of pacnreatic cancer cells

目的 观察胰腺星状细胞（PSC）对人胰腺癌细胞株增殖能力的影响,探讨其分子机制.方法 用免疫印迹实验检测成纤维细胞生长因子（FGFs）在胰腺癌细胞及PSC中的表达及分泌;噻唑蓝（MTT）比色法检测PSC细胞条件培养基（CDM）对胰腺癌细胞体外增殖的影响,以及除去FGFs之后影响的变化;MTT法检测PSC细胞CDM对Cyclopamine抑制胰腺癌细胞增殖作用的影响;体内实验观察PSC对胰腺癌细胞成瘤能力的影响.结果 PSC主要表达并分泌FGF2,而胰腺癌MIA PaCa-2和PANC-1细胞则主要表达FGF5;PSC细胞CDM刺激48 h后,胰腺癌MIA PaCa-2和PANC-1细胞体外增殖能力分别为对照组的（1.2993±0.1170）倍和（1.2447±0.0123）倍（P＜0.05）;中和CDM中FGFs后,FGFs（-）CDM对胰腺癌细胞增殖的刺激作用显著削弱;与单纯注射胰腺癌PANC-1细胞的裸鼠皮下种植瘤比较,PSC与PANC-1细胞混合注射组的平均肿瘤体积、质量均明显增加,分别由380.13 mm3和170 g增加至601.31 mm3和349 g（P＜0.05）;PSC细胞CDM处理后,Cyclopamine对胰腺癌MIA PaCa-2和PANC-1细胞的增殖抑制作用显著下降（P＜0.01）.结论 PSC在体内、体外均显著刺激胰腺癌细胞的增殖,增强其成瘤能力,其机制与PSC旁分泌FGF2作用于癌细胞相关;PSC显著降低了胰腺癌细胞对Hedgehog信号通路特异性抑制剂Cyclopamine治疗的敏感性.

Objective To assess the effects of pancreatic stellate cells （PSC） on proliferation of pancreatic cancer cells and to reveal its possible mechanism. Methods Expression and secretion of fibroblast growth factor （FGF） ligands in both pancreatic cancer cells and stellate cells were determined by immunoblotting analysis. Mmethyl thiazol tetrazolium （MTT） assay was used to examine the effects of conditioned medium （CDM） of PSC on the proliferation of pancreatic cancer cells. An in vivo tumorigenicity assay was used to evaluate the effect of PSC on xenograft formation in cancer cells. Results FGF2 was predominantly expressed and secreted by PSC. Yet MIA PaCa-2 and PANC-1 pancreatic cancer cells mainly expressed FGF5. CDM of PSC enhanced the proliferation of MIA PaCa-2 and PANC-1 cells for （ 1. 2993 ±0. 1170 ,P 〈0. 05 ） times and （ 1. 2447 ±0. 0123 ,P 〈0. 05 ） times, respectively. Neutralizing the effects of FGFs in the CDM by heparin-sepharose precipitation abolished this effect. The volume and weight of subcutaneous tumors in nude mice by injection of combination of pancreatic cancer cells with PSC were significantly greater than those by injection of PANC-1 cells alone （380. 13 mm3 and 170 g versus 601.31 mm3and 349 g,P 〈0. 05, respectively）. The CDM of PSC reduced the antiproliferative effect by cyclopamine on pancreatic cancer cells （ P 〈 0. 01, respectively）. Conclusion We identified in this study a mechanism based on stroma-tumor interactions involving PSC that can contribute to enhance the proliferation of human pancreatic cancer cells.