Enhanced anti-tumor effects of recombinant adenovirus expressing ING4 and IL-24 gene on PC3 prostate cancer cells and the mechanisms in vitro and in vivo

Abstract

Objective To construct a recombinant adenoviral vector co-expressing inhibitor of growth 4 (ING4) and interleukin-24 (IL-24) (Ad-ING4-IL-24) and study its enhanced anti-tumor effects on PC3 prostate cancer cells and the mechanism.Methods Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting were used to detect the expression of ING4 and IL-24 in PC3 cells.The growth inhibition and apoptosis effect were measured by methylthiazol tetrazolium (MTT) and flow cytometry (FCM) respectively.semi-quantitative RT-PCR and Western blotting were used to detect the expression of cell apoptosis-related genes ( bcl-2,bax and Caspase-3 ) in PC3 cells.In athymic nude mice bearing PC3 tumors,Ad-ING4-IL-24 was intratumorally injected,and the changes in the tumor growth were observed.The expression of bcl-2,bax,Caspase-3 and CD34 genes was examined by using immumohistochemistry.Results Ad-ING4-IL-24 was proved successfully transcribed and translated into PC3 cells,significantly inhibited growth of PC3 cells,and exerted enhanced anti-tumor effects.Ad-ING4-IL-24 induced apoptosis by up-regulating the expression of p53,hax and Caspase-3 and downregulating the expression of bcl-2.In vivo,intratumoral injection of Ad-ING4-IL-24 suppressed the tumor growth obviously with a inhibition rate of 74%.Immumohistochemistry revealed that the expression of bax and Caspase-3 was up-regulated and that of bcl-2 and CD34 was down-regulated by Ad-ING4-IL-24.Conclusion Ad-ING4-IL-24 could obviously inhibit the growth of PC3 cells,induce apoptosis and exert the enhanced anti-tumor effects s in vitro and in vivo by up-regulating p53,bax,Caspase-3 and down-regulating bcl-2 and CD34. Key words: ING4; IL-24; Adenovirus vector; Prostatic carcinoma; Tumor-suppression