Induction Of Apoptosis Of Rectal Carcinoma Cell Line HR8348 By 5-Fluorouracil In Vitro

Objective To study the effect of 5-Fu-induced apoptosis of the rectal carcinoma cell line HR8348 in vitro and the relationship between apoptosis induced by 5-Fu and the expressions of bcl-2 ,bcl-x1, bax and p53,and to investigate the possible mechanism of apoptosis of rectal carcinoma cell line HR8348 induced by 5-Fu.Method With 24 hour of 5-Fu treatment,the apoptotic index were detected by methyl green and pyronine y staining and by TDT-mediated dUTP nick end labeling(TUNEL).The bcl-2 bcl-x1 bax and p53 gene expressions of HR8348 cells were examined by immunohistochemical method.Results With 24 hour of 5-Fu treatment ,typical apoptosis of rectal carcinoma HR8348 cell line could be observed by methyl green and pyronine y staining and TUNEL,the apoptotic index(AI) of experiment groups was significantly increased ,there was significant difference compared with the controls (p<0.01) .With 12h, 24h and 36h of 5-Fu treatment ,the bcl-2 gene expression of rectal carcinoma HR8348 cell line remained unchanged,there was no significant difference compared with the controls (p>0.05 ) ,thre was also no significant difference among the the bcl-2 expression of different time (p>0.05) ; the expression of bcl-xl slightly diminished, but mere were no significant difference among thebcl-xl expression of different time (p>0.05 ) ,there was also no significant difference compared with the controls (p>0.05) ;with the prolonging of 5-Fu treatment , the expression of bax remarkly increased,the bax expressions at 24h and 36h of 5-Fu trteatment were great than that at 12h of 5-Fu treatment and that of the controls (p<0.01) ; with the prolonging of 5-Fu treatment,the ratio of bax to bcl-xl and bax to bcl-2 in experiemt groups gradually increased and were great than that in the controls;the expression of p53 was not detected in both experiment and control groups.Conclusion This results indicate that 5-Fu may induce apoptosis of rectal carcinoma cell line HR8348 in vitro and the possible mechanism of apoptosis induction was through upregulation of bax expression and the change of bax to bcl-xl and (or) bax to bcl-2 ratio.