生长激素对胰腺癌细胞pJAK2表达的影响

Impact of growth hormone on expression of phospho-JAK2（pJAK2）in pancreatic carcinoma cells-in vitro and in vivo

目的 观察生长激素（GH）作用前后胰腺癌细胞中GH-磷酸化Janus激酶2（pJAK2）信号转导通路的特征,探讨GH对胰腺癌细胞作用的分子机制.方法 不同浓度的GH（50、100 μg/L）作用于胰腺癌细胞（SW-1990、Cap-1、ASPC）,计数培养24、48、72h后的细胞数;收集SW-1990注射于裸鼠背部皮下,成瘤后随机分为注射GH的实验组（GH组,共21只,每日4 mg/kg共2周,1、2、24 h取材,每组7只）及注入盐水的对照组（NS组,7只）,注射期间隔日测量瘤体积.Western blot方法观察GH作用后不同时间（体外,GH 50μg/L：5、10、15、30、45min、1、2 h;体内：1、2、24 h）胰腺癌细胞pJAK2表达变化.结果 GH可刺激SW-1990、Cap-1、ASPC增殖但在体内不促进肿瘤牛长：pJAK2在7株胰腺细胞（SW-1990、Cap-1、Colo、Mia、Aspc、P3、Panc-1）均有不同程度的表达;与细胞毒T淋巴细胞（CTL）比较,GH刺激后pJAK2表达显著增强（5、10、15 min尤为明显）,但1、2 h有减弱趋势;GH应用于裸鼠后各时间点（1、2、24 h）pJAK2在移植瘤中的表达差异无统计学意义.结论 GH能促进胰腺癌细胞SW-1990、Cap-1、ASPC增殖,但在体内不刺激肿瘤生长;GH可显著增强pJAK2在SW-1990中的表达,而在体内这种变化不明显.

Objective To observe the impact of growth hormone （GH） on expression of phosphoJAK2 （pJAK2） in pancreatic carcinoma cells and to discuss significance of pJAK2 in signaling.Methods （1）Pancreatic carcinoma cells （SW-1990,Cap-1,ASPC） during exponential growth stage were harvested and cultured in medium containing growth hormone（50 μg/L,100μg/L）;After 24,48,72 hours,cells were counted using a Coulter Counter.（2）Athymic nude BALB/C mice were inoculated with SW-1990 cells,When tumors became palpable after inoculation.animals were randomized to receive GH（4 mg/kg.s.c.once daily for 2 weeks,n=21）versus saline control cytotoxic lymphocyte（CTL,n=7）.（3）Human pancreatic carcinoma cell lines（SW-1990,Cap-1,Colo,Mia,Aspc,P3,Panc-1） were collected to detect the basal expression of pJAK2 with immol/lunoblots;After GH administration on special times（in vitro：5,10,15,30,45 min,1,2 h;in vivo：1,2,24 h）,Cells were collected and Tumor tissues of the mice were rapidly incised respectively.All the specimen were frozen immol/lediately for subsequent Western blotting analysis,to ohserve the impact of GH on expression of pJAK2 in SW-1990 and inoculation tumor cells.Results The results revealed GH stimulated cell growth in vitro;On immol/lunoblots,positive expression of pJAK2 was observed on human pancreatic carcinoma cell lines（SW-1990、Cap-1、Colo、Mia、Aspc、P3、Panc-1）.GH augmented rapidly tyrosine phosphorylation of this special proteins to the highest value on the 5th minute after GH administration in vitro and the values fluctuated later;No similar phenomena,however,were observed in vivo.Conclusion Positive expression of pJAK2 is observed on human pancreatic cancer ceils;Furthermore,GH augments rapidly tyrosine phosphorylation of these special proteins not in vivo but in vitro;and this discrepancy helps to explain why GH doesn＇t accelerate tumor growth in vivo.