Aims: Hepatocellular carcinoma (HCC) is the most common liver cancer worldwide. IFN-alpha has been used in clinics as a potential therapeutic strategy to treat HCC. In spite of the therapeutic effects, IFN-alpha caused many side effects due to its short half-life and high dose. Here, we aim to detect the anti-tumor effect of a novel gene delivery system - IFN-alpha 2b gene-modified human bone marrow mesenchymal stem cells (BMSCs) in HCC. Main methods: Two HCC cell lines, HepG2 and Huh7 were used in the current study. The secretion of IFN-alpha 2b in the BMSC cultured conditioned media (CM) was measured by ELISA. The cell cycle was determined by flow cytometry. The Xenografted NOD/SCID mouse tumor model was generated by subcutaneous inoculation with HepG2 cells. Key findings: We found that the IFN-alpha 2b-modified BMSC (BMSC/IFN-alpha 2b) could express IFN-alpha 2b stably. The CM from BMSC/IFN-alpha 2b inhibited the proliferation of HCC cells with a much lower growth rate compared with BMSC/vector-CM or DMEM culture group. We further demonstrated that the population of G2/M phase was higher in BMSC/IFN-alpha 2b-CM treated cells than the other two groups. In addition, BMSC/IFN-alpha 2b could significantly inhibit tumor growth in NOD/SCID mice. Moreover, we found that BMSC/IFN-alpha 2b-CM could significantly decrease the mRNA and protein levels of Notch signaling molecules of HCC in vitro and in vivo. Significance: Our data demonstrated that BMSC/IFN-alpha 2b could significantly inhibit HCC cell growth through negatively regulating the Notch signaling, which suggested that IFN-alpha 2b-modified BMSC may be used as an effective therapeutic strategy for hepatomas. (C) 2015 Elsevier Inc. All rights reserved.