生长激素对胰腺癌细胞pJAK2表达的影响

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.

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

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.