Targeting an engineered cytokine with interleukin-2 and interleukin-15 activity to the neovasculature of solid tumors.

Michael R Mortensen,Marco Catalano,Jacqueline Mock,Marco Bertolini,Dario Neri,Marco Stringhini

doi:10.18632/oncotarget.27772

Abstract

There is a growing interest in the antibody-based delivery of cytokines to the tumor environment as a means to boost the anti-cancer activity of tumor-resident T cells and NK cells. Here, we describe the expression and characterization of fusion proteins, featuring the L19 antibody (specific to the alternatively-spliced EDB domain of fibronectin) and an engineered cytokine with interleukin-2 and interleukin-15 properties. The cytokine moiety was fused either at the N-terminal or at the C-terminal extremity and both fusion proteins showed a selective tumor accumulation in a quantitative biodistribution experiment. The N-terminal fusion inhibited tumor growth in immunocompetent mice bearing F9 carcinomas or WEHI-164 sarcomas when used as single agent. The anticancer activity was compared to the one of the same cytokine payload used as recombinant protein or fused to an anti-hen egg lysozyme antibody, serving as negative control of irrelevant specificity in the mouse. These results indicate that the antibody-based delivery of engineered cytokines to the tumor neovasculature may mediate a potent anticancer activity.

Highlights

IntroductionCancer immunotherapy relies on the activation of certain leukocytes (most typically, T cells and/or natural killer cells), with the aim to induce a selective biocidal activity against tumor cells
Cancer immunotherapy relies on the activation of certain leukocytes, with the aim to induce a selective biocidal activity against tumor cells
In 1992, interleukin (IL)-2 was approved as the first cancer immunotherapy, providing a long-term survival benefit to a small proportion of patients with metastatic melanoma or renal cell carcinoma [10,11,12]

Summary

Introduction

Cancer immunotherapy relies on the activation of certain leukocytes (most typically, T cells and/or natural killer cells), with the aim to induce a selective biocidal activity against tumor cells. IL2 muteins may alter the interaction of the cytokine with one or more of the IL2 receptor subunits [20], altering the selectivity towards the intermediate affinity receptor [consisting of CD122 (IL2Rβ) and CD132 (γC)] or towards the high affinity receptor [consisting of CD25 (IL2Rα), CD122, and CD132] [28]. The strength of the interaction of IL2 with the cognate intermediate affinity receptor was increased through mutations, which stabilized folding [34]. An increased selectivity towards the intermediate affinity IL2 receptor was achieved by blocking the interaction with CD25 either through IL2 mutations or by antibody blockade of the IL2 epitope involved in CD25 binding [31,32,33, 35]. A decreased IL2 toxicity was observed in CD25 knock-out mice [36]

Methods

Results

Conclusion