PLoS ONE (Jan 2015)

Favorable alteration of tumor microenvironment by immunomodulatory cytokines for efficient T-cell therapy in solid tumors.

  • Siri Tähtinen,
  • Saija Kaikkonen,
  • Maiju Merisalo-Soikkeli,
  • Susanna Grönberg-Vähä-Koskela,
  • Anna Kanerva,
  • Suvi Parviainen,
  • Markus Vähä-Koskela,
  • Akseli Hemminki

DOI
https://doi.org/10.1371/journal.pone.0131242
Journal volume & issue
Vol. 10, no. 6
p. e0131242

Abstract

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Unfavorable ratios between the number and activation status of effector and suppressor immune cells infiltrating the tumor contribute to resistance of solid tumors to T-cell based therapies. Here, we studied the capacity of FDA and EMA approved recombinant cytokines to manipulate this balance in favor of efficient anti-tumor responses in B16.OVA melanoma bearing C57BL/6 mice. Intratumoral administration of IFN-α2, IFN-γ, TNF-α, and IL-2 significantly enhanced the anti-tumor effect of ovalbumin-specific CD8+ T-cell (OT-I) therapy, whereas GM-CSF increased tumor growth in association with an increase in immunosuppressive cell populations. None of the cytokines augmented tumor trafficking of OT-I cells significantly, but injections of IFN-α2, IFN-γ and IL-2 increased intratumoral cytokine secretion and recruitment of endogenous immune cells capable of stimulating T-cells, such as natural killer and maturated CD11c+ antigen-presenting cells. Moreover, IFN-α2 and IL-2 increased the levels of activated tumor-infiltrating CD8+ T-cells concomitant with reduction in the CD8+ T-cell expression of anergy markers CTLA-4 and PD-1. In conclusion, intratumoral administration of IFN-α2, IFN-γ and IL-2 can lead to immune sensitization of the established tumor, whereas GM-CSF may contribute to tumor-associated immunosuppression. The results described here provide rationale for including local administration of immunostimulatory cytokines into T-cell therapy regimens. One appealing embodiment of this would be vectored delivery which could be advantageous over direct injection of recombinant molecules with regard to efficacy, cost, persistence and convenience.