Inhibiting effect of IL-24 combined with targeting attenuated Salmonella vector SL 7207/pBud-Vp3 on growth of gastric cancer cells / 重庆医学

ABSTRACT

Objective To investigate the inhibiting effect of interleukin (IL)‐24 combined with targeted attenuated Salmonella typhimurium vector SL7207/pBud‐VP3 on the growth of gastric cancer cells .Methods The co‐expression eukaryotic expression plasmid pBud‐VP3‐IL‐24 was constructed .The plasmid pBud‐VP3‐IL‐24 was transformed into attenuated Salmonella typhimurium SL7207 by using the high voltage electroporation for constructing the SL 7207/pBud‐VP3‐IL‐24 strain .The mouse gastric cancer transplantation tumor model was established and randomly divided into the normal saline control group ,SL7207/pBud group , SL7207/pBud‐VP3 group and SL7207/pBud‐VP3‐IL‐24 group .The tumor‐bearing mice were fed by oral administration of bacterial strain .The tumor volume was measured and the tumor inhibition rate was calculated .The expression of IL‐24 was detected by Western blotting .The levels of IFN‐γ,IL‐6 and TNF‐αin tumor tissue were detected by using RT‐PCR .The expression of Caspase‐3 and VEGF were detected by using immunohistochemistry .Results The plasmids attenuated Salmonella typhimurium vector carrying the gene IL‐24 was successfully constructed .The IL‐24 protein expression was detected in gastric cancer tissue after 14 d treatment .The tumor volume after 28 d treatment in the SL7207/pBud‐VP3‐IL‐24 group was reduced compared with the other groups ,moreover the tumor growth was significantly inhibited ,and the differences were statistically significant (P<0 .05) .RT‐PCR and immunohistochemistry results showed that IL‐24 combined with SL7207/bBud‐VP3 could significantly increase the expression levels of immune factor IL‐6 ,IFN‐γ and TNF‐αin tumor tissue ,.in addition ,up‐regulated the expression of Caspase‐3 and down‐regulated the VEGF expression(P<0 .05) .Conclu‐sion IL‐24 combined with SL7207/pBud‐VP3 can synergically play the inhibitory effect on the growth of gastric cancer cells ,its mecha‐nism is related with the tumor apoptosis promotion ,tumor vessel inhibition and immune regulation .