A Glycoengineered Interferon-β Mutein (R27T) Generates Prolonged Signaling by an Altered Receptor-Binding Kinetics

Recent and future perspectives on engineering interferons and other cytokines as therapeutics

As crucial mediators and regulators of our immune system, cytokines are involved in a broad range of biological processes and are implicated in various disease pathologies. The field of cytokine therapeutics has gained much momentum from the maturation of conventional protein engineering methodologies such as structure-based designs and/or directed evolution, which is further aided by the advent of in silico protein designs and characterization. Just within the past 5 years, there has been an explosion of proof-of-concept, preclinical, and clinical studies that utilize an armory of protein engineering methods to develop cytokine-based drugs. Here, we highlight the key engineering strategies undertaken by recent studies that aim to improve the pharmacodynamic and pharmacokinetic profile of interferons and other cytokines as therapeutics.

Emerging glyco-based strategies to steer immune responses

Glycan structures are common posttranslational modifications of proteins, which serve multiple important structural roles (for instance in protein folding), but also are crucial participants in cell-cell communications and in the regulation of immune responses. Through the interaction with glycan-binding receptors, glycans are able to affect the activation status of antigen-presenting cells, leading either to induction of pro-inflammatory responses or to suppression of immunity and instigation of immune tolerance. This unique feature of glycans has attracted the interest and spurred collaborations of glyco-chemists and glyco-immunologists to develop glycan-based tools as potential therapeutic approaches in the fight against diseases such as cancer and autoimmune conditions. In this review, we highlight emerging advances in this field, and in particular, we discuss on how glycan-modified conjugates or glycoengineered cells can be employed as targeting devices to direct tumor antigens to lectin receptors on antigen-presenting cells, like dendritic cells. In addition, we address how glycan-based nanoparticles can act as delivery platforms to enhance immune responses. Finally, we discuss some of the latest developments in glycan-based therapies, including chimeric antigen receptor (CAR)-T cells to achieve targeting of tumor-associated glycan-specific epitopes, as well as the use of glycan moieties to suppress ongoing immune responses, especially in the context of autoimmunity.

Antibody-Based Targeting of Interferon-Beta-1a Mutein in HER2-Positive Cancer Enhances Antitumor Effects Through Immune Responses and Direct Cell Killing

Type I interferon (IFN) has been approved as an anticancer agent to treat some malignancies. However, IFNs have a short in vivo half-life, systemic toxicity, and poor biophysical properties, which prevent it from being widely used for cancer therapy. This study aimed to construct recombinant IFN-β-1a mutein immunocytokines that comprise a human epidermal growth factor receptor 2 (HER2)-targeting antibody and IFN-β muteins with an additional glycosylation, which can overcome the limitation of the cytokine itself. Hence, the molecular design aims to 1) enhance productivity and biophysical properties by adding secondary glycosylation in IFN-β, 2) increase the therapeutic index of IFN-β therapy by preferential retention at the tumor by possessing high affinity for HER2-expressing cancer cells, and 3) improve the pharmacokinetics and, thus, the convenience of IFN-β administration. The yield of trastuzumab-IFN-β mutein was higher than that of trastuzumab-wild-type IFN-β in the mammalian cell culture system. Trastuzumab-IFN-β mutein showed similar IFN activity and HER2-targeting ability equivalent to that of IFN-β mutein and trastuzumab, respectively. Trastuzumab-IFN-β mutein directly inhibited the growth of HER2-positive gastric cancer cell lines and was more effective than trastuzumab or IFN-β mutein alone. Trastuzumab-IFN-β mutein and IFN-β mutein displayed enhanced immune cell-mediated cytotoxicity. Collectively, trastuzumab-IFN-β mutein may have indirect immune cell-mediated antitumor effects and direct cell growth inhibitory effects. Tumor-targeting effect of trastuzumab-IFN-β mutein was analyzed using in vivo fluorescence imaging. The accumulation of trastuzumab-IFN-β mutein was observed in HER2-positive tumors rather than other tissues except the liver. To evaluate the both direct tumor growth inhibition effect and indirect immune cell-mediated antitumor effect, we tested the effect of trastuzumab-IFN-β mutein in HER2-positive cancer xenograft models using nude mice or humanized mice. Trastuzumab-IFN-β mutein could significantly enhance tumor regression when compared with trastuzumab or IFN-β mutein. In addition, an increase in tumor-infiltrating lymphocytes was observed in the trastuzumab-IFN-β mutein-treated group, implying that the tumor-targeting IFN-β may have an enhanced antitumor effect through increased immune response. Therefore, targeting IFN-β with an anti-HER2 monoclonal antibody makes the immunocytokine more potent than either agent alone. These novel findings suggest that trastuzumab-IFN-β mutein merits clinical evaluation as a new candidate of anticancer therapeutics.

Glycosylation Heterogeneity of Hyperglycosylated Recombinant Human Interferon-β (rhIFN-β)

We previously developed a biobetter version of rhIFN-β (R27T) that possesses an additional glycosylation site compared with rhIFN-β 1a. Herein, we characterized N-glycosylation heterogeneity of R27T, which includes both N-glycan site occupancy heterogeneity (macro-heterogeneity) and complexity of carbohydrate moieties (micro-heterogeneity). N-glycan site occupancy manifested as distinct differences in size and isoelectric point. The analysis of complex carbohydrate moieties of R27T involved the common biopharmaceutical glycosylation critical quality attributes such as core fucosylation, antennary composition, sialylation, N-acetyllactosamine extensions, linkages, and overall glycan profiles using weak anion-exchange and hydrophilic interaction high-performance liquid chromatography with 2-aminobenzoic acid-labeled N-glycans. The double-glycosylated form accounted for approx. 94% R27T, while the single-glycosylated form accounted for 6% R27T. N-glycans consisted of a mixture of bi-, tri-, and tetra-antennary glycans, some with N-acetyllactosamine extensions, but neither outer arm fucose nor α-galactose was detected. Sialic acid major variants, N-acetyl- and N-glycolyl-neuraminic acid, were more abundant in R27T than in Rebif. The major N-glycan, accounting for ∼42% of total N-glycans, had a di-sialylated, core-fucosylated bi-antennary structure.