戊地昔布对裸鼠食管癌移植瘤凋亡的影响及其可能机制

目的探讨戊地昔布对裸鼠食管癌移植瘤凋亡的影响及其可能机制。方法建立食管癌裸鼠原位移植瘤模型,给予戊地昔布4 wk。剥离瘤结节,计算瘤体体积和肿瘤生长抑制率;FCM法检测移植瘤中的细胞凋亡率;免疫组织化学和FCM法检测COX-2、c-jun和c-fos蛋白的表达变化;RT-PCR检测移植瘤中COX-2 mRNA表达变化。结果①用戊地昔布的裸鼠组,裸鼠体重明显增加,且随用药时间延长,其体重也随之增加。②戊地昔布可明显降低肿瘤重量,肿瘤生长抑制率为45.80%。③戊地昔布可增加肿瘤细胞的凋亡率。④戊地昔布可下调COX-2 mRNA和蛋白的表达;同时凋亡基因c-jun和c-fos蛋白表达升高。⑤肿瘤组织的凋亡率与COX-2蛋白表达呈负相关(r=-0.726,P=0.008),与c-jum、c-fos蛋白表达呈正相关。⑥给予戊地昔布后,裸鼠胃肠上皮细胞形态没有明显异常。结论戊地昔布能够抑制裸鼠移植瘤的生长和诱导凋亡,其机制部分与抑制COX-2表达及上调凋亡基因c-jun,c-fos有关。

Effects and possible mechanism of valdecoxib on apoptosis of canceRin nude mice

Aim To investigate the effects and possible mechanism of valdecoxib on apoptosis of cancer in nude mice.Methods The tumor model was established by inoculating 2×106 cell both in the left and right armpit respectively.The mice were divided randomly into control group and valdecoxib group(20 mg·kg-1·day-1).Valdecoxib was dissolved in carboxymethylcellulose sodium and administered from the second day after inoculation.The mice were killed after 4 weeks.The volumn and inhibitory rate were calculated according to the length and width of xenograft tumor.H.E staining was used to observe the cell structure of the stomach and colon.The apoptotic rate was detected by FCM.The expression of COX-2,c-jun and c-fos protein was detected by FCM and immunohistochemical staining.Total RNA was extracted with Trizol method and the expression of COX-2 mRNA was detected by RT-PCR.Results(1) The body weight of nude mice was higher in valdecoxib treated group in a time-dependent manner.(2) Valdecoxib inhibited the growth of tumor.The weight of tumor was decreased from(1.43±0.52)g in control group to(0.93±0.53)g in valdecoxib treated group.The ratio of inhibition on the growth of tumor was 45.80%.(3) Valdecoxib increased the apoptosis rate from(14.15±0.48)% in control group to(29.80±6.35)% in treated group.(4) The expression of COX-2 mRNA and protein decreased in treated group compared with that in control group.FCM and immunohistochemical staining showed that the expressions of c-jun and c-fos were increased in valdecoxib treated group.There was statistical significance compared with control group.(5) There was significantly negative correlation between the ratio of apoptosis and the expression of COX-2(r=-0.726,P=0.008);there was significantly positive correlation between the ratio of apoptosis and the expressions of c-jun and c-fos protein respectively(r=0.603,0.813;P=0.038,0.001);(6) Valdecoxib did not affect cell structure of stomach and colon.Conclusions valdecoxib inhibits the growth of the xenograft tumor in nude mice and induces the apoptosis.Decreasing expression of COX-2 and up-regulating the expressions of c-jun and c-fos may be one of the mechanisms for the apoptosis.