Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Cancer Immunol Immunother. 2012 Mar;61(3):425-31. doi: 10.1007/s00262-011-1188-y. Epub 2011 Dec 23.

Gene silencing of TGF-β1 enhances antitumor immunity induced with a dendritic cell vaccine by reducing tumor-associated regulatory T cells.

Author information

  • 1Immune Regulation Research Group, School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Room 4.04, Pearse Street, Dublin 2, Ireland.

Abstract

Active immunotherapy and cancer vaccines that promote host antitumor immune responses promise to be effective and less toxic alternatives to current cytotoxic drugs for the treatment of cancer. However, the success of tumor immunotherapeutics and vaccines is dependent on identifying approaches for circumventing the immunosuppressive effects of regulatory T (Treg) cells induced by the growing tumor and by immunotherapeutic molecules, including Toll-like receptor (TLR) agonists. Here, we show that tumors secrete high concentrations of active TGF-β1, a cytokine that can convert naive T cells into Foxp3+ Treg cells. Silencing TGF-β1 mRNA using small interfering RNA (siRNA) in tumor cells inhibited active TGF-β1 production in vitro and restrained their growth in vivo. Prophylactic but not therapeutic administration of TGF-β1 siRNA reduced the growth of CT26 tumors in vivo. Furthermore, suppressing TGF-β1 expression at the site of a tumor, using siRNA before, during and after therapeutic administration of a TLR-activated antigen-pulsed dendritic cell vaccine significantly reduced the growth of B16 melanoma in mice. The protective effect of co-administering TGF-β1 siRNA with the DC vaccine was associated with suppression of CD25+ Foxp3+ and CD25+ IL-10+ T cells and enhancement of tumor infiltrating CD4 and CD8 T cells. Our findings suggest that transient suppression of TGF-β1 may be a promising approach for enhancing the efficacy of tumor vaccines in humans.

PMID:
22193988
[PubMed - indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Icon for Springer
    Loading ...
    Write to the Help Desk