Double-Regulated Oncolytic Adenovirus-Mediated Interleukin-24 Overexpression Exhibits Potent Antitumor Activity on Gastric Adenocarcinoma

Evaluation of the oncolytic property of recombinant Newcastle disease virus strain R2B in 4T1 and B16-F10 cells in-vitro

Recombinant Newcastle disease virus vectors have gained a lot of interest for its oncolytic virus therapy and cancer immune therapeutic properties due to its selective replication to high titers in cancer cells. The aim of this study was to find out the oncolytic effects of mesogenic recombinant NDV strain R2B-GFP on murine mammary tumor cell line 4T1 and murine melanoma cell line B16-F10. The anti-tumor effects of R2B-GFP virus were studied via expression of virus transgene GFP in cancer cells, evaluating its cytotoxicity and cell migration efficacies by MTT and wound healing assays respectively. In addition, the underlying apoptotic mechanism of R2B-GFP virus was estimated by TUNEL assay, colorimetric estimation of Caspase-3, 8 and 9 and the estimation of Bax to Bcl-2 ratio. The results showed a significant decrease in viability of both 4T1 and B16-F10 cells infected with R2B-GFP virus at 0.1 and 1 MOI. R2B-GFP virus could significantly induce apoptosis in the 4T1 and B16-F10 cells as compared to the uninfected control. Further, a flow cytometry analysis on apoptotic cells percentage and mitochondria membrane permeability test was also studied in R2B-GFP virus treated 4T1 and B16-F10 cell lines. The R2B-GFP virus caused an increase in loss of mitochondrial membrane permeability in both 4T1 and B16-F10 cells indicating the involvement of mitochondrial regulated cell death. Thus, the recombinant virus R2B-GFP virus proved to be a valid candidate for oncolytic viral therapy in 4T1 and B16-F10 cells.

Oncolytic Newcastle disease virus reduces growth of cervical cancer cell by inducing apoptosis

Although Oncolytic viruses have been regarded as a promising tool for targeted therapy of cancer, accomplishing high efficacy and specificity with this strategy is challenging. Oncolytic virotherapy is one of the novel therapeutic methods recently used for the therapy of human malignancies. Cervical cancer is on the major public health problem and the second most common cause of cancer death among females in less developed countries. The aim of this study was mainly to determine the apoptosis effect of oncolytic Newcastle disease virus (NDV) in TC-1 cell line.

In the current study, the oncolytic NDV, vaccine strain LaSota, was used to infect murine TC-1 cells of human papillomavirus (HPV)-associated carcinoma which expressing human papillomavirus 16 (HPV-16) E6/E7 antigens in vitro. The effectiveness of NDV for cervical cancer cell line was investigated by evaluating the antitumor activity of oncolytic NDV and the involved mechanisms. Antitumor activities of oncolytic NDV were assessed by cell proliferation (MTT) and lactate dehydrogenase (LDH) release analysis. In addition, molecular changes of early stage of apoptosis and the role of reactive oxygen species (ROS) were analyzed by flow cytometry and Western Blot in NDV-treated TC-1 cells.

The results showed that NDV treatment significantly decreased the viability of a TC-1 cell line and suppressed the growth by inducing apoptotic cell death. In addition, we demonstrated that NDV-induced apoptosis of TC-1 cells is mediated by ROS production. In summary, our findings suggest that oncolytic NDV is a possible therapeutic candidate as a selective antitumor agent for the treatment of cervical cancer.

Enhanced tumor growth inhibition by mesenchymal stem cells derived from iPSCs with targeted integration of interleukin24 into rDNA loci

Induced pluripotent stem cells (iPSCs) are a promising source of mesenchymal stem cells (MSCs) for clinical applications. In this study, we transformed human iPSCs using a non-viral vector carrying the IL24 transgene pHrn-IL24. PCR and southern blotting confirmed IL24 integration into the rDNA loci in four of 68 iPSC clones. We then differentiated a high expressing IL24-iPSC clone into MSCs (IL24-iMSCs) that showed higher expression of IL24 in culture supernatants and in cell lysates than control iMSCs. IL24-iMSCs efficiently differentiated into osteoblasts, chondrocytes and adipocytes. Functionally, IL24-iMSCs induced in vitro apoptosis in B16-F10 melanoma cells more efficiently than control iMSCs when co-cultured in Transwell assays. In vivo tumor xenograft studies in mice demonstrated that IL24-iMSCs inhibited melanoma growth more than control iMSCs did. Immunofluorescence and histochemical analysis showed larger necrotic areas and cell nuclear aggregation in tumors with IL24-iMSCs than control iMSCs, indicating that IL24-iMSCs inhibited tumor growth by inducing apoptosis. These findings demonstrate efficient transformation of iPSCs through gene targeting with non-viral vectors into a rDNA locus. The ability of these genetically modified MSCs to inhibit in vivo melanoma growth is suggestive of the clinical potential of autologous cell therapy in cancer.

Suppression of Her2/Neu mammary tumor development in mda-7/IL-24 transgenic mice

Melanoma differentiation associated gene-7/interleukin-24 (mda-7/IL-24) encodes a tumor suppressor gene implicated in the growth of various tumor types including breast cancer. We previously demonstrated that recombinant adenovirus-mediated mda-7/IL-24 expression in the mammary glands of carcinogen-treated (methylnitrosourea, MNU) rats suppressed mammary tumor development. Since most MNU-induced tumors in rats contain activating mutations in Ha-ras, which arenot frequently detected in humans, we presently examined the effect of MDA-7/IL-24 on Her2/Neu-induced mammary tumors, in which the RAS pathway is induced. We generated tet-inducible MDA-7/IL-24 transgenic mice and crossed them with Her2/Neu transgenic mice. Triple compound transgenic mice treated with doxycycline exhibited a strong inhibition of tumor development, demonstrating tumor suppressor activity by MDA-7/IL-24 in immune-competent mice. MDA-7/IL-24 induction also inhibited growth of tumors generated following injection of Her2/Neu tumor cells isolated from triple compound transgenic mice that had not been treated with doxycycline, into the mammary fat pads of isogenic FVB mice. Despite initial growth suppression, tumors in triple compound transgenic mice lost mda-7/IL-24 expression and grew, albeit after longer latency, indicating that continuous presence of this cytokine within tumor microenvironment is crucial to sustain tumor inhibitory activity. Mechanistically, MDA-7/IL-24 exerted its tumor suppression effect on HER2⁺ breast cancer cells, at least in part, through PERP, a member of PMP-22 family with growth arrest and apoptosis-inducing capacity. Overall, our results establish mda-7/IL-24 as a suppressor of mammary tumor development and provide a rationale for using this cytokine in the prevention/treatment of human breast cancer.

Suppression effect of recombinant adenovirus vector containing hIL-24 on Hep-2 laryngeal carcinoma cells

The melanoma differentiation-associated gene-7 [MDA-7; renamed interleukin (IL)-24] was isolated from human melanoma cells induced to terminally differentiate by treatment with interferon and mezerein. MDA-7/IL-24 functions as a multimodality anticancer agent, possessing proapoptotic, antiangiogenic and immunostimulatory properties. All these attributes make MDA-7/IL-24 an ideal candidate for cancer gene therapy. In the present study, the human MDA-7/IL-24 gene was transfected into the human laryngeal cancer Hep-2 cell line and human umbilical vein endothelial cells (HUVECs) with a replication-incompetent adenovirus vector. Reverse transcription polymerase chain reaction and western blot analysis confirmed that the Ad-hIL-24 was expressed in the two cells. The expression of the antiapoptotic gene, Bcl-2, was significantly decreased and the IL-24 receptor was markedly expressed in Hep-2 cells following infection with Ad-hIL-24, but not in HUVECs. In addition, the expression of the proapoptotic gene, Bax, was induced and the expression of caspase-3 was increased in the Hep-2 cells and HUVECs. Methyl thiazolyl tetrazolium assay indicated that Ad-hIL-24 may induce growth suppression in Hep-2 cells but not in HUVECs. In conclusion, Ad-hIL-24 selectively inhibits proliferation and induces apoptosis in Hep-2 cells. No visible damage was found in HUVECs. Therefore, the results of the current study indicated that Ad-hIL-24 may have a potent suppressive effect on human laryngeal carcinoma cell lines, but is safe for healthy cells.

Oncolytic adenovirus encoding tumor necrosis factor-related apoptosis inducing ligand (TRAIL) inhibits the growth and metastasis of triple-negative breast cancer

Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) is a promising cancer therapeutic target due to its selective apoptosis-inducing effect in cancer cells. To efficiently deliver TRAIL to the tumor cells, an oncolytic adenovirus (p55-hTERT-HRE-TRAIL) carrying the TRAIL coding sequence was constructed. In the present study, we aimed to investigate the effect of p55-hTERT-HRE-TRAIL on the growth and metastasis of triple-negative breast cancer (TNBC). We observed that infection of the recombinant adenovirus resulted in expression of TRAIL and massive cell death in a TNBC cell line MDA-MB-231. This effect is much weaker in MCF-10A, which is a normal breast cell line. Administration of P55-HTERT-HRE-TRAIL significantly reduced orthotopic breast tumor growth and extended survival in a metastatic model. Our results suggest the oncolytic adenovirus armed with P55-HTERT-HRE-TRAIL, which exhibited enhanced anti-tumor activity and improved survival, is a promising candidate for virotherapy of TNBC.

Reversal effect of melanoma differentiation associated gene-7/interleukin-24 on multidrug resistance in human hepatocellular carcinoma cells

Multidrug resistance is the main cause for failure of chemotherapy. Melanoma differentiation associated gene-7/interleukin-24 (mda-7/IL-24) has been implicated in the inhibition of human tumor cell proliferation. However, the reversing effect of mda-7/IL-24 on multidrug resistance of human hepatocellular carcinoma (HCC) is not fully clear. In this study, we investigated the effects of overexpression of the mda-7/IL-24 gene in human HCC. We established mda-7/IL-24 overexpressing BEL-7402/5-fluorouracil (5-FU) cell lines and their drug sensitivity to 5-FU and doxorubicin (DOX) which were investigated by MTT. Furthermore, we investigated the apoptotic rate and the intracellular accumulation of Rhodamine-123 and DOX by flow cytometry. We also studied the expression of multidrug resistance gene 1 (MDR1), lung resistance-related protein (LRP), and multidrug resistance-related protein 1 (MRP1) by real-time polymerase chain reaction and Western blotting. Transcriptional activation of AP-1 and NF-κB was determined by luciferase reporter assay. The drug sensitivity of 5-FU or DOX, the apoptotic rate, and the intracellular accumulation of Rhodamine-123 and DOX were increased, while the mRNA and protein expression levels of MDR1, LRP, and MRP1 were reduced. The transcriptional activation of AP-1 and NF-κB was suppressed in mda-7/IL-24 overexpressing BEL-7402/5-FU cells. Our results demonstrated that mda-7/IL-24 could restore the drug sensitivity through the downregulation of MDR1, MRP1, and LRP expression, as well as the transcriptional activation of AP-1 and NF-κB and effectively reverse MDR.

Oncolytic adenovirus armed with IL-24 inhibits the growth of breast cancer in vitro and in vivo

Background

Interleukin-24 (IL-24) is a cytokine that belongs to the IL-10 family. It can selectively induce cancer cell apoptosis which has been utilized as a cancer gene therapy strategy.

Methods

A recombinant type five adenovirus containing IL-24 gene (designated CNHK600-IL24) was constructed, whose replication is activated only in tumor cells. The replication of CNHK600-IL24 in breast tumor cells and fibroblasts were assessed by TCID50 and MTT assay; the secretion of IL-24 was measured by ELISA and western blotting. The in vivo anti-tumor effect of CNHK600-IL24 was investigated in nude mice carrying orthotopic or metastatic breast tumor.

Results

We observed that CNHK600-IL24 could replicate efficiently and resulted in high level IL-24 expression and massive cell death in human breast cancer cell MDA-MB-231 but not in normal fibroblast cell MRC-5. In addition, orthotopic breast tumor growth in the nude mice model was significantly suppressed when CNHK600-IL24 was administered. In the metastatic model generated by tail vein injection, CNHK600-IL24 virotherapy significantly improved survival compared with the same virus expressing EGFP (median survival CNHK600-IL24, 55 days vs. CNHK600-EGFP, 41 day, p < 0.05 Mantal-Cox test). A similar phenomenon was observed in the metastatic model achieved by left ventricular injection as suggested by in vivo luminescence imaging of tumor growth.

Conclusion

The oncolytic adenovirus armed with IL-24, which exhibited enhanced anti-tumor activity and improved survival, is a promising candidate for virotherapy of breast cancer.

Interferon-α enhances antitumor activities of oncolytic adenovirus-mediated IL-24 expression in hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) has a dismal 5-year-survival rate of 10%, so novel strategies are warranted. IL-24 mediates anti-tumor activity reducing STAT3 expression, which suggests that interferon (IFN) alpha may augment tumor cell lysis and reduce angiogenesis. We investigated the antitumor activity of treatment with IFN-α, with the oncolytic adenovirus SG600-IL-24, or the combination of both in HCC in vitro and in vivo.

Results

RT-PCR, ELISA assay and Western-blot confirmed that the exogenous IL-24 gene was highly expressed in HCC cells infected with SG600-IL-24. Treatment with combined IFN-α and SG600-IL-24 suppressed growth and promoted apoptosis of the HepG2, MHCC97L, and HCCLM3 cell lines compared with the normal cell line L02. The combined therapy increased STAT1 and SOCS1 and apoptosis, but decreased the expression of the metastatic and angiogenic proteins MMP-2, XIAP, OPN, and VEGF, which are regulated by STAT3 in HCC cells in vitro. To assess the effects in vivo, the HCC cell line HCCLM3 was transplanted subcutaneously into the right flanks of nude mice. Mice in the IFN-α group, the SG600-IL-24 group, or the combined therapy group had significantly suppressed growth of the HCC xenografted tumors compared to the PBS control group of mice. Among the mice treated with the combination of IFN-α and SG600-IL-24, three of those eight mice had long-term survival and no evidence of a tumor. These mice also had decreased expression of the metastatic and angiogenic proteins MMP-2, XIAP, OPN, and VEGF.

Conclusions

The present study demonstrated for the first time the potential antitumor activity of IFN-α combined with the oncolytic adenovirus SG600-IL-24 in HCC both in vitro and in vivo, and suggests its further development as a potential candidate for HCC cancer gene therapy.

Conditionally replicating adenoviruses carrying mda-7/IL-24 for cancer therapy

BACKGROUND

Melanoma differentiation associated gene-7/interleukin-24 (mda-7/IL-24) suppresses growth and induces apoptosis in a broad range of human cancers without significant cytotoxicity to normal cells. Conditionally replicating adenoviruses (CRAds) not only have the ability to destroy cancer cells but may also be potential vectors for the expression of therapeutic genes.

METHODS

This review provides an overview of specifications for a novel anti-tumor approach CRAds carrying IL-24, and discusses recent progress in this field.

RESULTS

Studies in multiple laboratories report that CRAds carrying IL-24 selectively induced apoptosis in some cancer cells, and enhanced selective toxicity to cancer cells when combined with chemotherapeutic agents.

CONCLUSION

CRAds carrying IL-24 may prove a novel and effective approach for the treatment of cancers.

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), enzyme-linked 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)-2,5-diphenyltetrazolium 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.