Antibody-Based Delivery of Cytokine Payloads to Carbonic Anhydrase IX Leads to Cancer Cures in Immunocompetent Tumor-Bearing Mice

A novel nanobody-based immunocytokine of a mutant interleukin-2 as a potential cancer therapeutic

The immunotherapeutic application of interleukin-2 (IL-2) in cancer treatment is limited by its off-target effects on different cell populations and insufficient activation of anti-tumor effector cells at the site of the tumor upon tolerated doses. Targeting IL-2 to the tumor microenvironment by generating antibody-cytokine fusion proteins (immunocytokine) would be a promising approach to increase efficacy without associated toxicity. In this study, a novel nanobody-based immunocytokine is developed by the fusion of a mutant (m) IL-2 with a decreased affinity toward CD25 to an anti-vascular endothelial growth factor receptor-2 (VEGFR2) specific nanobody, denoted as VGRmIL2-IC. The antigen binding, cell proliferation, IFN-γ-secretion, and cytotoxicity of this new immunocytokine are evaluated and compared to mIL-2 alone. Furthermore, the pharmacokinetic properties are analyzed. Flow cytometry analysis shows that the VGRmIL2-IC molecule can selectively target VEGFR2-positive cells. The results reveal that the immunocytokine is comparable to mIL-2 alone in the stimulation of Primary Peripheral Blood Mononuclear Cells (PBMCs) and cytotoxicity in in vitro conditions. In vivo studies demonstrate improved pharmacokinetic properties of VGRmIL2-IC in comparison to the wild or mutant IL-2 proteins. The results presented here suggest VGRmIL2-IC could be considered a candidate for the treatment of VEGFR2-positive tumors.

Nanobodies in cytokine‑mediated immunotherapy and immunoimaging (Review)

Cytokines are the main regulators of innate and adaptive immunity, mediating communications between the cells of the immune system and regulating biological functions, including cell motility, differentiation, growth and apoptosis. Cytokines and cytokine receptors have been used in the treatment of tumors and autoimmune diseases, and to intervene in cytokine storms. Indeed, the use of monoclonal antibodies to block cytokine‑receptor interactions, as well as antibody‑cytokine fusion proteins has exhibited immense potential for the treatment of tumors and autoimmune diseases. Compared with these traditional types of antibodies, nanobodies not only maintain a high affinity and specificity, but also have the advantages of high thermal stability, a high capacity for chemical manipulation, low immunogenicity, good tissue permeability, rapid clearance and economic production. Thus, nanobodies have extensive potential for use in the diagnosis and treatment of cytokine‑related diseases. The present review summarizes the application of nanobodies in cytokine‑mediated immunotherapy and immunoimaging.

An Antibody Targeting Fibroblast Activation Protein Simultaneously Fused to Interleukin-2 and Tumor Necrosis Factor Selectively Localizes to Neoplastic Lesions

The delivery of specific cytokine payloads to a neoplastic environment employing antibodies able to selectively accumulate at the tumor site represents an attractive strategy to stimulate an immune response to cancer. Whilst conventional antibody-cytokine fusions based on a single payload have shown potent anticancer activity, the concomitant delivery of two cytokine payloads may further improve the therapeutic outcome as the immune system typically adopts multiple signals to reinforce an antitumor strategy. We here describe a potency-matched dual-cytokine antibody fusion protein containing a tumor-targeting antibody fragment specific to human fibroblast activation protein (FAP), simultaneously linked to both interleukin-2 (IL2) and a tumor necrosis factor (TNF) mutant. The resulting fusion protein, termed IL2-7NP2-TNF^mut, formed stable non-covalent trimers driven by the interaction of the tumor necrosis factor subunits. Both cytokine payloads retained their biological activity within the fusion protein, as shown by in vitro cellular assays. The tumor-targeting properties and the anticancer activity of IL2-7NP2-TNF^mut were investigated in vivo in immunocompromised mice bearing SKRC52 cells transduced with human FAP. The fusion protein preferentially localized to the cancer site and induced partial tumor retardation.

Carbonic anhydrase IX: A tumor acidification switch in heterogeneity and chemokine regulation

The primary physiological process of respiration produces carbon dioxide (CO₂) that reacts with water molecules which subsequently liberates bicarbonate (HCO-₃) and protons. Carbonic anhydrases (CAs) are the primary catalyst involved in this conversion. More than 16 isoforms of human CAs show organ or subcellular specific activity. Dysregulation of each CA is associated with multiple pathologies. Out of these members, the overexpression of membrane-bound carbonic anhydrase IX (CAIX) is associated explicitly with hypoxic tumors or various solid cancers. CAIX helps tumors deal with higher CO₂ by sequestering it with bicarbonate ions and helping cancer cells to grow in a comparatively hypoxic or acidic environment, thus acting as a pH adaptation switch. CAIX-mediated adaptations in cancer cells include angiogenesis, metabolic alterations, tumor heterogeneity, drug resistance, and regulation of cancer-specific chemokines. This review comprehensively collects and describe the cancer-specific expression mechanism and role of CAIX in cancer growth, progression, heterogeneity, and its structural insight to develop future combinatorial targeted cancer therapies.

IL12 immune therapy clinical trial review: Novel strategies for avoiding CRS-associated cytokines

Interleukin 12 (IL-12) is a naturally occurring cytokine that plays a key role in inducing antitumor immune responses, including induction of antitumor immune memory. Currently, no IL-12-based therapeutic products have been approved for clinical application because of its toxicities. On the basis of this review of clinical trials using primarily wild-type IL-12 and different delivery methods, we conclude that the safe utilization of IL-12 is highly dependent on the tumor-specific localization of IL-12 post administration. In this regard, we have developed a cell membrane-anchored and tumor-targeted IL-12-T (attIL12-T) cell product for avoiding toxicity from both IL-12 and T cells-induced cytokine release syndrome in peripheral tissues. A phase I trial using this product which seeks to avoid systemic toxicity and boost antitumor efficacy is on the horizon. Of note, this product also boosts the impact of CAR-T or TCR-T cell efficacy against solid tumors, providing an alternative approach to utilize CAR-T to overcome tumor resistance.

Engineering interferons and interleukins for cancer immunotherapy

Cytokines are a class of potent immunoregulatory proteins that are secreted in response to various stimuli and act locally to regulate many aspects of human physiology and disease. Cytokines play important roles in cancer initiation, progression, and elimination, and thus, there is a long clinical history associated with the use of recombinant cytokines to treat cancer. However, the use of cytokines as therapeutics has been limited by cytokine pleiotropy, complex biology, poor drug-like properties, and severe dose-limiting toxicities. Nevertheless, cytokines are crucial mediators of innate and adaptive antitumor immunity and have the potential to enhance immunotherapeutic approaches to treat cancer. Development of immune checkpoint inhibitors and combination immunotherapies has reinvigorated interest in cytokines as therapeutics, and a variety of engineering approaches are emerging to improve the safety and effectiveness of cytokine immunotherapy. In this review we highlight recent advances in cytokine biology and engineering for cancer immunotherapy.

Antibody-Drug Conjugate Targets, Drugs and Linkers

Antibody-drug conjugates offer the possibility of directing powerful cytotoxic agents to a malignant tumor while sparing normal tissue. The challenge is to select an antibody target expressed exclusively or at highly elevated levels on the surface of tumor cells and either not all or at low levels on normal cells. The current review explores 78 targets that have been explored as antibody-drug conjugate targets. Some of these targets have been abandoned, 9 or more are the targets of FDA-approved drugs, and most remain active clinical interest. Antibody-drug conjugates require potent cytotoxic drug payloads, several of these small molecules are discussed, as are the linkers between the protein component and small molecule components of the conjugates. Finally, conclusions regarding the elements for the successful antibody-drug conjugate are discussed.

Glyco-Coated CdSe/ZnS Quantum Dots as Nanoprobes for Carbonic Anhydrase IX Imaging in Cancer Cells

The bioimaging of cancer cells by the specific targeting of overexpressed biomarkers is an approach that holds great promise in the identification of selective diagnostic tools. Tumor-associated human carbonic anhydrase (hCA) isoforms IX and XII have been considered so far as well-defined biomarkers, with their expression correlating with cancer progression and aggressiveness. Therefore, the availability of highly performant fluorescent tools tailored for their targeting and able to efficiently visualize such key targets is in high demand. We report here on the design and synthesis of a kind of quantum dot (QD)-based fluorescent glyconanoprobe coated with a binary mixture of ligands, which, according to the structure of the terminal domains, impart specific property sets to the fluorescent probe. Specifically, monosaccharide residues ensured the dispersibility in the biological medium, CA inhibitor residues provided specific targeting of membrane-anchored hCA IX overexpressed on bladder cancer cells, and the quantum dots imparted the optical/fluorescence properties.

An antibody-based enzymatic therapy for cancer treatment: The selective localization of D-amino acid oxidase to EDA fibronectin

In order to generate an antibody directed enzyme prodrug therapy, here we designed a chimeric protein by fusing the F8 antibody that recognizes the EDA of fibronectin (expressed on the tumor neovasculature) and an evolved variant of the ROS-generating enzyme D-amino acid oxidase (DAAO). The F8(scFv)-DAAO-Q144R recombinant protein is expressed by both CHO-S and E. coli cells. The F8(scFv)-DAAO-Q144R from E. coli cells is fully soluble, shows a high specific activity, is more thermostable in blood than the native DAAO, possesses a binding affinity for EDA well suited for efficient tumor accumulation, and localizes in tumor tissues. Notably, the F8(scFv)-DAAO-Q144R conjugate generates a stronger cytotoxicity to tumor cells than the native enzyme, especially when an inhibitor of heme oxygenase-1 (HO-1) is used, making it a promising candidate for a selective antitumor oxidative therapy controlled by the substrate addition, in the so called "activity on demand", thus sparing normal tissue from damage.

Utilizing Immunocytokines for Cancer Therapy

Cytokine therapy for cancer has indicated efficacy in certain diseases but is generally accompanied by severe toxicity. The field of antibody-cytokine fusion proteins (immunocytokines) arose to target these effector molecules to the tumor environment in order to expand the therapeutic window of cytokine therapy. Pre-clinical evidence has shown the increased efficacy and decreased toxicity of various immunocytokines when compared to their cognate unconjugated cytokine. These anti-tumor properties are markedly enhanced when combined with other treatments such as chemotherapy, radiotherapy, and checkpoint inhibitor antibodies. Clinical trials that have continued to explore the potential of these biologics for cancer therapy have been conducted. This review covers the in vitro, in vivo, and clinical evidence for the application of immunocytokines in immuno-oncology.

Exosomal microRNA-210 is a potentially non-invasive biomarker for the diagnosis and prognosis of glioma

MicroRNAs (miRs) transferred by exosomes can function as non-invasive potential biomarkers for the diagnosis and prognosis in various types of cancer. The present study examined the diagnostic and prognostic value of serum exosomal-(exo-)miR-210 levels in association with hypoxic conditions in patients with glioma. Serum levels of exo-miR-210 were determined by quantitative PCR in samples obtained from patients with glioma. Patients were divided into low-and high-expression exo-miR-210 groups according to the median expression value. Statistical analyses were conducted to examine the potential value of exo-miR-210 in predicting the diagnosis and prognosis of patients with glioma. A significant increase in serum exo-miR-210 levels was observed in patients with glioma compared with healthy controls. Additionally, the expression levels of exo-miR-210 were increased with ascending pathological grades. Furthermore, expression levels of miR-210 in serum exosomes from patients with glioblastoma were markedly decreased following surgery and upregulated once more at the recurrences of primary tumors, indicating that exo-miR-210 could reflect alterations in malignant glioma loads. In addition, Kaplan-Meier analysis was performed to analyze overall survival (OS) time. Patients with malignant glioma with high exo-miR-210 expression exhibited a poorer OS compared with patients with low expression. Importantly, univariate and multivariate Cox regression analysis revealed that the expression levels of exo-miR-210 in glioma serum samples were independently associated with OS. Finally, increased serum exo-miR-210 expression was positively associated with high levels of hypoxia-inducible factor 1a and reflected hypoxia in patients with glioma. In conclusion, serum levels of exo-miR-210 may serve as a diagnostic, prognostic and hypoxic biomarker to reflect glioma status and hypoxic signatures.

A Novel Fully-Human Potency-Matched Dual Cytokine-Antibody Fusion Protein Targets Carbonic Anhydrase IX in Renal Cell Carcinomas

Certain cytokines synergize in activating anti-cancer immunity at the site of disease and it may be desirable to generate biopharmaceutical agents, capable of simultaneous delivery of cytokine pairs to the tumor. In this article, we have described the cloning, expression and characterization of IL2-XE114-TNF^mut, a dual-cytokine biopharmaceutical featuring the sequential fusion of interleukin-2 (IL2) with the XE114 antibody in scFv format and a tumor necrosis factor mutant (TNF^mut). The fusion protein recognized the cognate antigen (carbonic anhydrase IX, a marker of hypoxia and of renal cell carcinoma) with high affinity and specificity. IL2-XE114-TNF^mut formed a stable non-covalent homotrimeric structure, displayed cytokine activity in in vitro tests and preferentially localized to solid tumors in vivo. The product exhibited a partial growth inhibition of murine CT26 tumors transfected for carbonic anhydrase IX. When administered to Cynomolgus monkey as intravenous injection, IL2-XE114-TNF^mut showed the expected plasma concentration of ~1,500 ng/ml at early time points, indicating the absence of any in vivo trapping events, and a half-life of ~2 h. IL2-XE114-TNF^mut may thus be considered as a promising biopharmaceutical for the treatment of metastatic clear-cell renal cell carcinoma, since these tumors are known to be sensitive to IL2 and to TNF.