Oncolytic adenovirus-mediated MDA-7/IL-24 overexpression enhances antitumor activity in hepatocellular carcinoma cell lines

BACKGROUND: Melanoma differentiation-associated gene-7 (MDA-7)/interleukin-24 (IL-24) is a novel tumor suppressor gene, which has suppressor activity in a broad spectrum of human cancer cells. We investigated the effect of the replication-competent oncolytic adenovirus SG600-IL24 and replication-incompetent adenovirus Ad.IL-24, both expressing human MDA-7/IL-24 on the hepatocellular carcinoma cell lines HepG2, Hep3B, SMMC-7721, HCCLM3, and the normal liver cell line L02. METHODS: Hepatocellular carcinoma cell lines and the normal liver cell line were infected with SG600-IL24 and Ad.IL-24. The mRNA and protein expression of MDA-7/IL-24 in infected cells was confirmed by RT-PCR, ELISA, and Western blotting. MTT assay was used to investigate the proliferation effect. Hoechst staining and Annexin-V and PI staining were performed to study the MDA-7/IL-24 gene expressed in HCC cell lines and the normal liver cell line. Flow cytometry was used to analyse the cell cycle. RESULTS: RT-PCR, ELISA and Western blotting confirmed that the exogenous MDA-7/IL-24 gene was highly expressed in cells infected with SG600-IL24. MTT and apoptosis detection indicated that SG600-IL24 induced growth suppression, promoted apoptosis, and blocked cancer cell lines in the G2/M phase in hepatocellular carcinoma cell lines but not in the normal liver cell line. CONCLUSIONS: SG600-IL24 selectively induces growth suppression and apoptosis in hepatocellular carcinoma cell lines in vitro but not in the normal liver cell line L02. Compared with Ad.IL-24, SG600-IL24 dramatically enhances antitumor activity in hepatocellular carcinoma cell lines. (Hepatobiliary Pancreat Dis Int 2010; 9:615-621)

Targeted IL-24 gene therapy inhibits cancer recurrence after liver tumor resection by inducing tumor cell apoptosis in nude mice

BACKGROUND: Interleukin-24 (IL-24) is a novel candidate tumor suppressor that induces tumor cell apoptosis experimentally in a variety of human malignant cells including liver cancer cells. The present study was conducted to investigate the potential effect of recombinant adeno-associated virus (rAAV)-mediated IL-24 gene therapy on tumor recurrence and metastasis by inducing tumor cell apoptosis in a hepatocellular carcinoma (HCC) model in nude mice. METHODS: We established a recurrent and metastatic HCC model in nude mice and constructed an rAAV vector carrying alpha-fetoprotein (AFP) promoter for expressing the IL-24 gene (rAVV/AFP/IL-24). The vector was administered by regional injection (liver incisal margin). AFP was detected by radiation immunoassay. Histological evaluation of tumor recurrence and metastasis was performed for the liver and lung. The effect of tumor cell apoptosis was confirmed by TUNEL analysis. RESULTS: IL-24 gene therapy prevented tumor recurrence and metastasis, as evidenced by marked decreases in the number of metastatic tumor nodules and tumor volume in the liver and lung. At the same time, serum AFP concentration decreased markedly in the IL-24 group compared with the control or rAAV groups (P<0.05). IL-24 gene therapy inhibited tumor recurrence and metastasis as evidenced by the induction of tumor cell apoptosis. CONCLUSION: The results demonstrated that targeted IL-24 gene therapy was effective in the prevention of postoperative recurrence and metastasis in an HCC nude mice model by induction of tumor cells apoptosis with potential minimum tumor burden.

Oncolytic adenovirus SG600-IL24 selectively kills hepatocellular carcinoma cell lines

AIM: To investigate the effect of oncolytic adenovirus SG600-IL24 and replication-incompetent adenovirus Ad.IL-24 on hepatocellular carcinoma (HCC) cell lines and normal liver cell line. METHODS: HCC cell lines (HepG2, Hep3B and MHCC97L) and normal liver cell line (L02) with a different p53 status were infected with SG600-IL24 and Ad.IL-24, respectively. Melanoma differentiation-associated (MDA)-7/interleukin (IL)-24 mRNA and protein expressions in infected cells were detected by reverse transcription-polymerase chain reaction (RT-PCR), enzymelinked immunosorbent assay (ELISA), and Western blotting, respectively. Apoptosis of HCC cells and normal liver cells was detected by cytometric assay with Hoechst33258 staining. 3-(4,5-dimethylthiazol-2-yl)-2,5diphenyltetrazolium bromide (MTT) assay was used to investigate proliferation of HCC cells and normal liver cells, and cell cycle was assayed by flow cytometry. RESULTS: RT-PCR, ELISA and Western blotting showed that the exogenous MDA-7/IL-24 gene was highly expressed in cells infected with SG600-IL24. MTT indicated that SG600-IL24 could suppress the growth of HepG2, Hep3B, MHCC97L, with an inhibition rate of 75% ± 2.5%, 85% ± 2.0%, 72% ± 1.8%, respectively (P < 0.01), promote the apoptosis of HepG2, Hep3B, MHCC97L, with an apoptosis rate of 56.59% ± 4.0%, 78.36% ± 3.5%, 43.39% ± 2.5%, respectively (P < 0.01), and block the HCC cell lines in the G2/M phase with a blocking rate of 35.4% ± 4.2%, 47.3% ± 6.2%, 42% ± 5.0%, respectively (P < 0.01) but not the normal liver cell line in a p53-independent manner. CONCLUSION: SG600-IL24 can selectively suppress the proliferation and apoptosis of HCC cell lines in vitro but not normal liver cell line L02 in a p53-independent manner. Compared with Ad.IL-24, SG600-IL24 can significantly enhance the antitumor activity in HCC cell lines.

Effect of recombinant adenovirus vector mediated human interleukin-24 gene transfection on pancreatic carcinoma growth

Background Pancreatic cancer is a highly malignant tumor affecting an ever increasing number of patients with a mean 5-year survival rate below 4%. Therefore, gene therapy for cancer has become a potential novel therapeutic modality. In this study we sought to determine the inhibitory effects of adenovirus-mediated human interleukin-24 （AdhIL-24） on pancreatic cancer.Methods Human interleukin-24 gene was cloned into replication-defective adenovirus specific for patu8988 tumor cells by virus recombination technology. Reverse transcription-polymerase chain reaction and Western blotting analysis were used to determine the expression of human interleukin-24 mRNA in patu8988 cells in vitro. Induction of apoptosis by overexpression of human interleukin-24 in patu8988 cells was determined by flow cytometry. In vivo efficacy of adenoviral delivery of human interleukin-24 was assessed in nude mice （n=10 for each group） bearing patu8988 pancreatic cancer cell lines by determining inhibition of tumor growth, endothelial growth factor and CD34 expression, and intratumoral microvessel density （MVD）.Results The recombinant adenovirus vector AdVGFP/IL-24 was constructed with a packaged recombinant retrovirus titer of 1.0×10^10 pfu/ml and successfully expressed of both mRNA and protein in patu8988 cells. The AdVGFP/IL-24 induced apoptosis of patu8988 tumor cells in vitro and significantly inhibited tumor growth in vivo （P 〈0.05）. The intratumoral MVD decreased significantly in the treated tumors （P 〈0.05）.Conclusion The recombinant adenovirus AdGFP/IL-24 can effectively express biologically active human interleukin-24, which results in inhibition of pancreatic cancer growth.