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)

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.

Synergistic Antitumor Efficacy of Oncolytic Adenovirus Combined with Chemotherapy

Objective： Chemotherapy is an effective means of treating breast cancer, and cancer-specific replicative adenovirus is also a promising antitumor agent in recent years. Our investigation aims to demonstrate that CNHK300 can mediate selective antitumor efficacy and produce synergistic cytotoxicity with chemotherapy on HER-2 over-expressing breast cancer. Methods： We engineered the telomerase-dependent replicative adenovirus CNHK300 by placing the E1A gene under the control of the human hTERT promoter. By analysis of E1A expression, we proved the fidelity of hTERT promoter in adenovirus genome and the selective expression of E1A in telomerase-positive breast cancer cells but not in normal fibroblast cells. By proliferation test, we further showed efficient replication of CNHK300 in breast cancer cells with apparently attenuated proliferation in normal fibroblast cells. Finally, we demonstrated by MTT methods that CNHK300 virus caused potent cytolysis and produced synergistic cytotoxicity with chemotherapy in breast cancer cells with attenuated cytotoxicity on normal cells. Results： In this virus, the E1A gene is successfully placed under the control of the human hTERT promoter. CNHK300 virus replicated as efficiently as the wild-type adenovirus and caused intensive cell killing in HER-2 over-expressing breast cancer cells in vitro. In contrast, telomerase-negative normal fibroblast cells, which expressed no hTERT activity, were not able to support CNHK300 replication. Combined treatment of CNHK300 with paclitaxel improved cytotoxicity on cancer cells. Conclusion： We conclude that CNHK300 can produce selective antitumor efficacy and enhance the in vitro response of chemotherapy on HER-2 overexpressing breast cancer.

Combined use of chemotherapeutics and oncolytic adenovirus in treatment of AFP-expressing hepatocellular carcinoma

BACKGROUND: Hepatocellular carcinoma (HCC) which is always refractory to most chemotherapeutic agents may result in poor survival of patients with advanced HCC. Oncolytic adenovirus is a new form for cancer gene therapy via its ability to replicate and kill tumor cells in a tumor-specific manner. In order to eradicate tumors effectively, the combination of chemotherapeutic agents and oncolytic adenovirus has been considered. This study aimed to systematically analyze the possibility of synergistic cytotoxicity of oncolytic adenoviruses in combination with chemotherapeutic agents. METHODS: Several types of human HCC cell lines were used to determine the specificity and cytotoxicity of oncolytic adenovirus Ad5-HC and Ad5-AFP (IRES) by measuring cell viability in vitro and antitumor efficiency in vivo. The cytotoxicity of Ad5-HC and Ad5-AFP (IRES) combined with chemotherapeutic agents were also assessed by the methyl thiazolyl tetrazolium assay. RESULTS: Both Ad5-HC and Ad5-AFP (IRES) were significantly cytotoxic to HCC cells with great specificity in vitro and in vivo. The combination of oncolytic adenovirus with 5-FU, doxorubicin, and paclitaxel was synergistically effective for the killing of HCC cells. CONCLUSIONS: These data suggest that oncolytic adenovirus sensitize tumors to chemotherapy and the combination therapy of chemotherapeutic agents and oncolytic adenovirus has an enhanced antitumor effect on HCC cells. (Hepatobiliary Pancreat Dis Int 2009; 8: 282-287)