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Background: The human umbilical cord mesenchymal stem cells (hUCMSCs) have the ability to migrate into tumors and therefore have been considered as an alternative source of mesenchymal progenitors for the therapy of malignant diseases. The present study was aimed to investigate effect of hUCMSCs as vehicles for a constant source of transgenic interleukin-21 (IL-21) on ovarian cancer in vivo., Methods: The hUCMSCs were engineered to express IL-21 via lentiviral vector- designated 'hUCMSCs-LV-IL-21', and then were transplanted into SKOV3 ovarian cancer xenograft-bearing nude mice. The therapeutic efficacy and mechanisms of this procedure on ovarian cancer was evaluated., Results: The isolated hUCMSCs were induced to differentiate efficiently into osteoblast and adipocyte lineages in vitro. The expressed IL-21 in the supernatant from hUCMSCs-LV-IL-21 obviously stimulated splenocyte's proliferation. The hUCMSCs-LV-IL-21 significantly reduced SKOV3 ovarian cancer burden in mice indicated by tumor sizes compared with control mice. The expressed IL-21 not only regulated the levels of IFN-γ and TNF-α in the mouse serum but also increased the expression of NKG2D and MIC A molecules in the tumor tissues. The down regulation of β-catenin and cyclin-D1 in the tumor tissues may refer to the inhibition of SKOV3 ovarian cancer growth in mice. In addition, hUCMSCs did not form gross or histological teratomas up to 60 days posttransplantation in murine lung, liver, stomach and spleen., Conclusion: These results clearly indicate a safety and usability of hUCMSCs-LV- IL-21 in ovarian cancer gene therapy, suggesting the strategy may be a promising new method for clinical treatment of ovarian cancer.

The goal of this study was to investigate whether glycosylphosphatidylinositol (GPI)-anchored 6 kDa early secreted antigenic target (ESAT-6) and IL-21-producing B16F10/ESAT-6-GPI-IL-21 viable vaccine would induce antitumor efficacy. Mice were immunized with B16F10/ESAT-6-GPI-IL-21 vaccine and challenged by B16F10 cells 2 weeks later. Antitumor efficacy and mechanisms of the vaccine were analyzed. Vaccination with the viable B16F10/ESAT-6-GPI-IL-21 vaccine resulted in an increase of IFN-γ level and the CD8(+)CTL cytotoxicity, a decrease in TGF-β generation and increase in the expression of miR-200c that serves as melanoma suppressor by directly targeting zinc-finger E-box binding homeobox 1 to inhibit epithelial-mesenchymal transition and block tumor metastasis. The vaccine significantly inhibited the melanoma growth, reduced the lung melanoma nodules, and prolonged the mouse survival compared with the controls. These findings highlighted IL-21 as an immune adjuvant in an engineered viable tumor vaccine to reinforce heterogenetic antigen ESAT-6 immune tolerance break to induce powerful antitumor efficacy in mice.

Ovarian cancer causes more deaths than any other cancer of the female reproductive system, and its overall cure rate remains low. The present study investigated human umbilical blood mononuclear cell (UBMC)-derived mesenchymal stem cells (UBMC-MSCs) as interleukin-21 (IL-21) gene delivery vehicles for ovarian cancer therapy in nude mice. MSCs were isolated from UBMCs and the expanded cells were phenotyped by flow cytometry. Cultured UBMCs were differentiated into osteocytes and adipocytes using appropriate media and then the UBMC-MSCs were transfected with recombinant pIRES2-IL-21-enhancement green fluorescent protein. UBMC-MSCs expressing IL-21 were named as UBMC-MSC-IL-21. Mice with A2780 ovarian cancer were treated with UBMC-MSC-IL-21 intravenously, and the therapeutic efficacy was evaluated by the tumor volume and mouse survival. To address the mechanism of UBMC-MSC-IL-21 against ovarian cancer, the expression of IL-21, natural killer glucoprotein 2 domain and major histocompatibility complex class I chain-related molecules A/B were detected in UBMC-MSC-IL-21 and in the tumor sites. Interferon-γ-secreting splenocyte numbers and natural killer cytotoxicity were significantly increased in the UBMC-MSC-IL-21-treated mice as compared with the UBMC-MSCs or the UBMC-MSC-mock plasmid-treated mice. Most notably, tumor growth was delayed and survival was prolonged in ovarian-cancer-bearing mice treated with UBMC-MSC-IL-21. Our data provide important evidence that UBMC-MSCs can serve as vehicles for IL-21 gene delivery and inhibit the established tumor., (Copyright © 2011 International Union of Biochemistry and Molecular Biology, Inc.)

In this paper, we addressed the immune adjuvant effects of interleukin(IL)-21 on DNA vaccine constructs expressing mycobacterium tuberculosis (TB) Ag85A and compared immune responses induced in mice inoculated DNA vaccine constructs expressing Ag85A and IL-21 with mice inoculated DNA vaccine constructs expressing Ag85A alone or Bacillus Galmette-Guérin(BCG.). In this experiment, the gene of IL-21 was firstly amplified from plasmid pcDNA3.1-mIL21 by PCR and cloned into the plasmid pRSC, forming recombinant plasmid pRSC-IL21. Then, the gene of Ag85A was amplified from the plasmid pIRES-Ag85A by PCR and cloned into the recombinant pRSC-IL21 again, finally forming co-expression DNA vaccine constructs pRSC-IL21-Ag85A. It was identified by the analysis of endonuclease digestion, DNA sequencing, the IL-21 and Ag85A expression in SP2/0 cells. Mice were i.m. immunized with BCG, DNA vaccine constructs pRSC-Ag85A or pRSC-IL21-Ag85A respectively, and the immune responses induced in mice was compared with other vaccines. The results showed that the DNA vaccine constructs pRSC-IL21-Ag85A was successfully constructed since the Ag85A and IL-21 was correctly expressed in SP2/0 cells respectively, and it elicited stronger immune responses in Balb/c mice than that of mice immunized with pRSC-Ag85A and the efficiency was as BCG did. We concluded that the IL-21 was a promising immune adjunctive modality to enhance immunigenicity of DNA vaccine containing Ag85A and the study provided the possibility of further development of immune accessory effect of IL-21 on DNA vaccine against TB.

Interleukin-21 (IL-21) is a recently characterized T cell-derived cytokine with a significant homology to IL-2, IL-4 and IL-15. To determine whether IL-21 has broad immunoregulatory activity and can stimulate durable antitumour responses, we constructed mouse IL-21 (mIL-21) recombinant plasmid and evaluated its antitumor efficacy. Mouse IL-21 cDNA was amplified from Con A-activated mouse T cells by RT-PCR. Recombinant pcDNA3.1/mIL-21 was constructed and transfected into Sp2/0 cells. Mouse IL-21 expression was analyzed by Western blotting and its activities were detected by 3H-TdR incorporation and MTT assay. The recombinant pcDNA3.1/mIL-21 was injected s.c. into tumor lump. Tumor size, weight, the activities of CTLs, NK cells and LAK cells and serum IFN-gamma level were measured for evaluating mIL-21 mediated antitumor responses. The results indicated that mIL-21 was correctly expressed in Sp2/0 cells and it can improve the proliferation of T cells and B cells, and enhance NK cytotoxic activity in vitro. The activities of CTL and NK cells, and serum IFN-gamma level were significantly improved, furthermore the tumor growth was obviously suppressed in pcDNA3.1/mIL-21 treated mice. However, the LAK activity did not alter significantly. Taken together, this study suggests that the injection with recombinant plasmid containing mIL-21 is a potential approach for tumor gene therapy.