Scientific publications

Intratumoral injection of IL-12-encoding mRNA targeted to CSFR1 and PD-L1 exerts potent anti-tumor effects without substantial systemic exposure

Jul 19, 2023 | Magazine: Molecular Therapy. Nucleic Acids

Claudia Augusta Di Trani  1   2 , Assunta Cirella  1   2 , Leire Arrizabalaga  1   2 , Maite Alvarez  1   2   3 , Ángela Bella  1   2 , Myriam Fernandez-Sendin  1   2 , Joan Salvador Russo-Cabrera  1   2 , Celia Gomar  1   2 , Nuria Ardaiz  1   2 , Alvaro Teijeira  1   2   3 , Elixabet Bolaños  1   2 , José González-Gomariz  1   2 , Itziar Otano  1   2 , Fernando Aranda  1   2 , Belén Palencia  1 , Aina Segués  4   5 , Shuyu Huang  4   5 , Sander M J van Duijnhoven  6 , Andrea van Elsas  7 , Ignacio Melero  1   2   3   8   9 , Pedro Berraondo  1   2   3


Abstract

IL-12 is a potent cytokine for cancer immunotherapy. However, its systemic delivery as a recombinant protein has shown unacceptable toxicity in the clinic. Currently, the intratumoral injection of IL-12-encoding mRNA or DNA to avoid such side effects is being evaluated in clinical trials.

In this study, we aimed to improve this strategy by further favoring IL-12 tethering to the tumor. We generated in vitro transcribed mRNAs encoding murine single-chain IL-12 fused to diabodies binding to CSF1R and/or PD-L1. These targeted molecules are expressed in the tumor microenvironment, especially on myeloid cells.

The binding capacity of chimeric constructs and the bioactivity of IL-12 were demonstrated in vitro and in vivo. Doses as low as 0.5 μg IL-12-encoding mRNA achieved potent antitumor effects in subcutaneously injected B16-OVA and MC38 tumors. Treatment delivery was associated with increases in IL-12p70 and IFN-γ levels in circulation. Fusion of IL-12 to the diabodies exerted comparable efficacy against bilateral tumor models.

However, it achieved tethering to myeloid cells infiltrating the tumor, resulting in nearly undetectable systemic levels of IL-12 and IFN-γ. Overall, tethering IL-12 to intratumoral myeloid cells in the mRNA-transferred tumors achieves similar efficacy while reducing the dangerous systemic bioavailability of IL-12.

CITATION  Mol Ther Nucleic Acids. 2023 Jul 19:33:599-616.  doi: 10.1016/j.omtn.2023.07.020. eCollection 2023 Sep 12.

Our authors

Dr. Álvaro Teijeira Sánchez