Oncolyic adenovirus SG600-IL24 expressing human melanoma differentiation associated gene-7/interleukin-24 selectively induces growth arrests and apoptosis in hepatocellular carcinoma cell lines

Abstract

Objective To investigate the effect of oncolytic adenovirus vector SG600-IL24 expressing human melanoma differentiation associated gene-7/interleukin-24 (MDA-7/IL-24) on hepatocellular carcinoma cell lines with different metastatic potentials (HepG2, Hep3B, SMMC7721 and normal liver cell line L02). Methods The oncolytic adenovirus SG600-IL24 carrying MDA-7/IL-24 gene was transfected into hepatocellular carcinoma cell lines and normal liver cell line. The mRNA and protein expression of MDA-7/IL-24 in HepG2, Hep3B, SMMC7721 and L02 cells was confirmed by reverse transcriptase-polymerase chain reaction (RT-PCR), enzyme linked immunosorbent assay (ELISA) and Western blotting respectively. Methyl thiazol tetrazolium (MTT) assay and flow cytometry were used to study tumor cell proliferation and cell cycle in vitro. Hoechst 33258 and flow cytometry were studied to indicate the apoptosis effects. Results It was confirmed by RT-PCR, ELISA and Western blotting that the exogenous MDA-7/IL-24 gene was highly expressed in HepG2, Hep3B, SMMC7721 and L02 cells. MTT and apoptosis detection indicated that MDA-7/IL-24 could induce the growth suppression [inhibition rate: (75.0±2.5)%, (85.0±2.0)%, and (86.0±3.5)% respectively. for HepG2: F=5.860; for Hep3B: F=7.210; for SMMC7721: F=7.980, P=0.000], promote apoptosis [apoptosis rate: (56.5±4.0)%, (34.4±2.0)% and (43.3±2.5)% respectively. For HepG2: F=203.400; for Hep3B: F=313.200; for SMMC7721: F=130.500, P=0.000], and block cancer cells in G2/M phase [the blocking rate: (35.4±4.2)%, (47.3±6.2)% and (40.5±5.0)%] but not L02 cells. Conclusion Oncolytic adenovirus vector SG600-IL24 can selectively induce growth suppression and promote apoptosis in hepatocellular carcinoma lines in vitro but not in L02 cells. Key words: Carcinoma, hepatocellular; Oncolytic viruses; Melanoma differentiation associated gene-7/interleukin-24 gene; Gene therapy