Objective: This study aims to investigate the using of bone marrow mesenchymal stem cells (BMSCs) genetically engineered to produce interferon-β (IFN-β) as a gene delivery system to treat hepatocellular carcinoma (HCC) in vitro and in vivo.
Methods: To measure the effects on tumour cell growth in vitro, IFN-β-producing BMSCs (BMSC/IFN-β) were co-cultured with the HCC cell line HepG2 and Huh7. Enzyme-linked immunosorbent assay (ELISA) was used to detect the IFN-β secretion in the BMSC culture condition medium (CM). The effect of BMSC/IFN-β on HCC cells proliferation was examined both in vitro and in vivo by using MTT, colony formation assay, BrdU staining, cell cycle analysis, and xenografted NOD/SCID mouse tumour model. To examine the impact of BMSC/IFN-β on the AKT/FOXO3a signalling, RT-PCR and western blotting were performed.
Results: The BMSC/IFN-β cells can stably secrete high levels of IFN-β. Both MTT and colony forming assay showed that HCC cells had a lower growth rate when cultured in BMSC/IFN-β-CM as compared with that in BMSC/vector-CM or DMEM culture group. Co-culture with BMSC/IFN-β-CM dramatically decreased the percentages of cells with incorporated BrdUrd. In BMSC/IFN-β-CM-treated HCC cells, the proportion of G1-phase cells increased but it decreased in the S phase of the cell. The BMSC/IFN-β inhibited HCC growth in NOD/SCID mice and proved the survival period of these mice. Compared with the control group, p21 and p27 expression of hepatoma cells increased, whereas cyclin D1 and phosphorylation of Rb expression decreased when co-cultured with BMSC/IFN-β-CM. It was associated with suppression of Akt activity and enhanced transcriptional activity of FOXO3a.
Conclusion: The IFN-β gene-modified BMSCs can effectively inhibit the proliferation of HCC cells in vitro and in vivo through inhibiting AKT/FOXO3a pathway. These results indicate that BMSC/IFN-β are a powerful anticancer cytotherapeutic tool for HCC.