Immunosuppressive Factor Blockade in Dendritic Cells via siRNAs Results in Objective Clinical Responses

  • Mouldy SioudEmail author
  • Anne Mobergslien
  • Stein Sæbøe-Larssen
Part of the Methods in Molecular Biology book series (MIMB, volume 1218)


Over the past decade, immunotherapy has emerged as a promising new form of cancer treatment with the potential to eradicate tumor metastasis. However, its curative potential is in general limited by the existence of negative feedback mechanisms that control dendritic cells (DCs) and T-cell activation. For clinically effective immunity, there is a need of inhibiting the expression of these immune suppressors. This could enhance the activation of DCs, T cells, and natural killer cells, and might be beneficial for cancer immunotherapy. Among the immune inhibitory molecules expressed by DCs is indoleamine 2,3-dioxygenase (IDO), an enzyme that conveys immunosuppressive effects by degrading tryptophan, an essential amino acid required for T-cell proliferation and survival. Depletion of tryptophan by IDO-positive DCs induces T-cell apoptosis and the conversion of naïve CD4+ T cells into regulatory T cells that further suppress antitumor immunity. Herein, we describe a protocol for in vitro synthesis of small interfering RNA against IDO and other immunosuppressive factors such as interleukin-10 and programmed cell death-1 ligands in order to reverse immune suppression mediated by DCs. Vaccination with IDO-silenced DC vaccines enhanced immune responses and antitumor immunity in cancer patients.

Key words

siRNA IDO Immunosuppression DC vaccine Immunotherapy 


  1. 1.
    Steinman RM, Banchereau J (2007) Taking dendritic cells into medicine. Nature 449:245–252CrossRefGoogle Scholar
  2. 2.
    Hoos A, Britten CM, Huber C, O’Donnell-Tormey J (2011) A methodological framework to enhance the clinical success of cancer immunotherapy. Nat Biotechnol 29:867–870PubMedCrossRefGoogle Scholar
  3. 3.
    Munn DH, Sharma MD, Lee JR, Jhaver KG, Johnson TS et al (2002) Potential regulatory function of human dendritic cells expressing indoleamine 2,3-dioxygenase. Science 297:1867–1870PubMedCrossRefGoogle Scholar
  4. 4.
    Hwu P, Du MX, Lapointe R, Do M, Taylor M-W, Young HA (2000) Indoleamine 2,3-dioxygenase production by human dendritic cells results in the inhibition of T cell proliferation. J Immunol 164:3596–3599PubMedCrossRefGoogle Scholar
  5. 5.
    Braun D, Longman RS, Albert ML (2005) A two-step induction of indoleamine 2,3 dioxygenase (IDO) activity during dendritic cell maturation. Blood 106:2375–2381PubMedCrossRefPubMedCentralGoogle Scholar
  6. 6.
    Munn DH, Sharma MD, Hou D (2004) Expression of indoleamine 2,3-dioxygenase by plasmacytoid dendritic cells in draining-draining lymph nodes. J Clin Invest 114:280–290PubMedCrossRefPubMedCentralGoogle Scholar
  7. 7.
    Jonuleit H, Schmitt E, Stenbrink K, Enk AH (2001) Dendritic cells as a tool to induce anergic and regulatory T cells. Trends Immunol 22:394–400PubMedCrossRefGoogle Scholar
  8. 8.
    Flatekval GF, Sioud M (2009) Modulation of dendritic cell function and maturation with mono- and bifunctional small interfering RNAs targeting indoleamine 2,3-dioxygenase. Immunology 128:e837–e848PubMedCrossRefPubMedCentralGoogle Scholar
  9. 9.
    Sioud M, Saebøe-Larssen S, Hetland TE, Kaern J, Mobergslien A, Kvalheim G (2013) Silencing of indoleamine 2,3-dioxygenase enhances dendritic cell immunogenicity and antitumour immunity in cancer patients. Int J Oncol 43:280–288PubMedGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  • Mouldy Sioud
    • 1
    Email author
  • Anne Mobergslien
    • 1
  • Stein Sæbøe-Larssen
    • 2
  1. 1.Department of Immunology, Institute for Cancer ResearchOslo University Radium Hospital, NorwayMontebello, OsloNorway
  2. 2.Department of Cell Therapy, Institute for Cancer ResearchOslo University Radium Hospital, NorwayMontebello, OsloNorway

Personalised recommendations