以靶向CSFR1和PD-L1的IL-12编码mRNA进行肿瘤内注射，具有强大的抗肿瘤效果而无明显的全身暴露。
Intratumoral injection of IL-12-encoding mRNA targeted to CSFR1 and PD-L1 exerts potent anti-tumor effects without substantial systemic exposure.
发表日期：2023 Sep 12
作者：
Claudia Augusta Di Trani, Assunta Cirella, Leire Arrizabalaga, Maite Alvarez, Ángela Bella, Myriam Fernandez-Sendin, Joan Salvador Russo-Cabrera, Celia Gomar, Nuria Ardaiz, Alvaro Teijeira, Elixabet Bolaños, José González-Gomariz, Itziar Otano, Fernando Aranda, Belén Palencia, Aina Segués, Shuyu Huang, Sander M J van Duijnhoven, Andrea van Elsas, Ignacio Melero, Pedro Berraondo
来源：
Molecular Therapy-Nucleic Acids
摘要：
IL-12 是一种用于癌症免疫疗法的强效细胞因子。然而，其作为重组蛋白的全身输送在临床中显示出不可接受的毒性。目前，临床试验正在评估肿瘤内注射 IL-12 编码的 mRNA 或 DNA 的方法，以避免此类副作用。在本研究中，我们旨在通过进一步使 IL-12 与肿瘤结合来改善这种策略。我们生成了体外转录的编码小鼠单链 IL-12 与结合 CSF1R 和/或 PD-L1 的二抗的 mRNA。这些靶向分子在肿瘤微环境中，特别是在骨髓细胞上表达。在体内外实验中，我们证明了嵌合构建物的结合能力和 IL-12 的生物活性。仅为 0.5 μg 的 IL-12 编码的 mRNA 剂量在皮下注射的 B16-OVA 和 MC38 肿瘤中达到了强效的抗肿瘤效果。治疗输送与循环中 IL-12p70 和 IFN-γ 水平的增加相关。将 IL-12 与二抗融合对双侧肿瘤模型展示了相当的功效。然而，它使结合肿瘤浸润的骨髓细胞，导致几乎无法检测到的系统性 IL-12 和 IFN-γ 水平。总体而言，在转移的肿瘤中将 IL-12 与肿瘤内骨髓细胞结合可以实现相似的功效，同时减少 IL-12 的危险的全身生物可用性。© 2023 The Author(s).
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.© 2023 The Author(s).