Bi-functional cytokine fusion proteins for gene therapy and antibody-targeted treatment of cancer

Typically, multiple cytokines act in concert to mediate a desired immunological response, and thus more effective therapeutics may be achieved by combining several cytokines with potentially synergistic activities. We have developed a series of bi-functional cytokine fusion proteins which, when additionally linked to an intact antibody (or the Fc portion of an antibody) in a variety of configurations, can be specifically targeted. We focus here mainly on the synergizing cytokine combination interleukin-2/interleukin-12 (IL-2/IL-12), but also demonstrate the utility of this approach with interleukin-4/granulocyte-macrophage colony-stimulating factor (IL-4/GM-CSF). Cytokine activity was retained in constructs where the cytokines were fused in tandem at the carboxyl terminus of the Fc or antibody heavy (H) chain, as well as in constructs where one cytokine was fused at the carboxyl terminus of the H chain while the second cytokine was fused to the amino terminus of either the H or light (L) chain variable region. Even in such constructs, antigen binding of the antibody-cytokine fusion proteins could be maintained. In the context of bi-functional fusion proteins, hetero-dimeric IL-12 could be expressed either in a single-chain form, or maintained as a heterodimer in which the p40 subunit was fused to IL-2. These IL-12/IL-2 bi-functional fusion proteins were shown to induce extremely high levels of interferon-gamma (IFN-gamma), similar to the synergy normally seen with the combined application of the individual cytokines. In addition, these bifunctional molecules were shown to have striking anti-tumor activity as either gene therapy or as an antibody cytokine(s) fusion protein, and may provide a useful approach to the treatment of cancer.     

Immunotherapy of human colon cancer by antibody-targeted superantigens

T lymphocytes generally fail to recognize human colon carcinomas, suggesting that the tumour is beyond reach of immunotherapy. Bacterial superantigens are the most potent known activators of human T lymphocytes and induce T cell cytotoxicity and cytokine production. In order to develop a T-cell-based therapy for colon cancer, the superantigen staphylococcal enterotoxin A (SEA) was given tumour reactivity by genetic fusion with a Fab fragment of the monoclonal antibody C242 reacting with human colon carcinomas. The C242Fab-SEA fusion protein targeted SEA-reactive T cells against MHC-class-II-negative human colon carcinoma cells in vitro at nanomolar concentrations. Treatment of disseminated human colon carcinomas growing in humanized SCID mice resulted in marked inhibition of tumour growth and the apparent cure of the animals. Therapeutic efficiency was dependent on the tumour specificity of the fusion protein and human T cells. Immunohistochemistry demonstrated massive infiltration of human T cells in C242Fab-SEA-treated tumours. The results merit further evaluation of C242Fab-SEA fusion proteins as immunotherapy in patients suffering from colon carcinoma.     

Assessment of atherosclerotic plaques in the rabbit abdominal aorta with interleukin-8 monoclonal antibody-targeted ultrasound microbubbles

In this study, we aimed to prepare a neovascularization-relevant inflammatory cytokine-targeted ultrasound contrast agent and apply it in the ultrasound imaging of atherosclerotic plaque. An interleukin-8 (IL-8) monoclonal antibody was conjugated to SonoVue microbubbles using the N-succinimidyl-3-(2-pyridyldithio)propionate cross-linking method. Then, a prepared IL-8-targeted contrast agent was used for contrast-enhanced ultrasound (CEU) to detect rabbit abdominal aorta atherosclerotic plaque and to investigate the imaging characteristics of atherosclerotic plaque with the contrast agent. We found that an IL-8 monoclonal antibody can be successfully coupled to SonoVue microbubbles with stable biological characteristics. CEU with this IL-8-targeted contrast agent can increase the atherosclerotic plaque detection sensitivity, with stronger echo, so that three more plaques were detected compared with using non-targeted SonoVue microbubbles. Thus, an inflammatory cytokine-targeting ultrasound contrast agent carrying IL-8 monoclonal antibody can provide unique advantages for researching the characteristics of atherosclerotic plaque.     

Simultaneous interaction of monoclonal antibody-targeted liposomes with two receptors on K562 cells

We have investigated the interaction of targeted liposomes with human erythrocytes, and K562 cells, a human leukemic line which expresses both glycophorin A and Fc receptors. Liposomes conjugated to monoclonal anti-human glycophorin A bind to human erythrocytes in 80-fold greater amounts than liposomes conjugated to a non-specific monoclonal antibody. Binding is inhibited by soluble anti-glycophorin but not by its Fab fragment. In contrast, binding of antibody-conjugated liposomes to K562 cells is very high irrespective of the specificity of the antibody. Liposomes conjugated to a nonspecific monoclonal antibody interact with K562 cells via an Fc receptor, and binding is inhibited by soluble human IgG. Liposomes conjugated to anti-human glycophorin A interact with K562 cells via an Fc receptor and glycophorin A. Binding is not inhibited by either human IgG or anti-glycophorin Fab alone. Binding is only partially inhibited by anti-glycophorin, or by human IgG in the presence of anti-glycophorin Fab, and completely inhibited only by human IgG in the presence of anti-glycophorin. Simultaneous binding of targeted liposomes to two cell membrane antigens is therefore partially resistant to inhibition by single soluble ligands even when they are present in large excess. We conclude that simultaneous binding to more than one receptor may be of considerable advantage for in vivo applications of targeted liposomes.     

基于单克隆抗体的肿瘤免疫疗法研究进展

一百多年前,"魔术子弹"学说首次提出了具有靶向特异性的抗体可以用来治疗疾病。此后,随着单克隆抗体制备技术的成熟,以及癌症血清疗法的发展,靶向肿瘤抗原的治疗性抗体开始进入临床,至今已有20余种抗体药物用于癌症的治疗。近两年,以免疫检查点蛋白拮抗剂、双特异性抗体、抗体药物偶联药物等为代表的新一代抗体药物,不断在治疗恶性肿瘤上取得突破性进展。本文回顾了抗肿瘤抗体的发展历程,总结了新一代抗体药物的作用机制与构建策略,以及主要临床副作用。并对基于抗体的肿瘤免疫疗法未来发展趋势进行了展望。     

Side-effects of monoclonal antibody infusions for the diagnosis and treatment of cancer

This literature review presents an inventory of the nature and incidence of side-effects that arise from the clinical application of monoclonal antibodies (MoAb) for the diagnosis and treatment of cancer. Most side-effects occurred during therapy. Toxic reactions, such as fever, sweating and chills, were more common than immunological skin reactions; they were observed predominantly in association with the elimination of circulating target cells. Dosage and rate of administration of the MoAb appeared to have little influence on the reactions, which disappeared quickly and did not necessitate discontinuation of treatment. Serum sickness, anaphylactic reactions and bronchospasms were not common; the patients reacted quickly to the indicated therapy. Prevention of the side-effects described here, especially during diagnostic applications, was such that they need not form a barrier to the clinical use of MoAb.     

An emerging role for nanomaterials in increasing immunogenicity of cancer cell death

In the last decade, it has become clear that anti-cancer therapy is more successful when it can also induce an immunogenic form of cancer cell death (ICD). ICD is an umbrella term covering several cell death modalities, including apoptosis and necroptosis. In general, ICD is characterized by the emission of damage-associated molecular patterns (DAMPs) and/or cytokines/chemokines, leading to the induction of strong anti-tumor immune responses. In experimental cancer therapy, new observations indicate that the immunogenicity of dying cancer cells can be improved by the use of biomaterials. In this review, after a brief overview of the basic principles of the concept of ICD and discussion of the potential use of DAMPs as biomarkers of therapy efficacy, we discuss an emerging role of nanomaterials as a promising strategy to modulate the immunogenicity of cancer cell death. We address how nanocarriers can be used to increase the immunogenicity of ICD and then turn our attention to their dual action. Nanocarriers can be used to increase the immunogenicity of dying cancer cells and to reduce the side effects of chemotherapy. Future studies will show whether biomaterials are truly an optimal strategy to modulate the immunogenicity of dying cancer cells and will provide the insights needed for the development of novel treatment strategies for cancer.     

ZnO nanomaterials target mitochondrial apoptosis and mitochondrial autophagy pathways in cancer cells

In recent years, the application of engineering nanomaterials has significantly contributed to the development of various biomedical fields. Zinc oxide nanomaterials (ZnO NMts) have gained wide popularity due to their biocompatibility, unique physical and chemical properties, stability, and cost-effectiveness for large-scale production. They have emerged as potential materials for anticancer applications. This article provides a comprehensive review of the synthesis methods of ZnO NMts and highlights the advantages of combining ZnO NMts with anticancer drugs as a nano platform for cancer treatment. Additionally, the article briefly explains the mechanism of action of ZnO NMts in tumor cells, focusing on the mitochondrial pathways that target cell apoptosis and autophagy. It is observed that these pathways are primarily influenced by reactive oxygen species generated through oxidative stress. The article discusses the promising prospects of ZnO NMts combined with anticancer drugs in the field of cancer medicine and emphasizes the need for further in-depth research on the mitochondrial apoptosis and mitochondrial autophagy pathways.     

Preparation and characterization of immunoconjugates for antibody-targeted photolysis.

Monoclonal antibody (MAb)-dextran-tin(IV) chlorin e6 (SnCe6) immunoconjugates were prepared by a new technique involving the use of reducing, terminal-modified dextran carriers and site-specific modification of the Fc oligosaccharide moiety on the antibodies. Dextran carriers were synthesized to increase the number of SnCe6 molecules attached to a MAb. The dextran carriers were coupled to the MAb via a single, chain-terminal hydrazide group to prevent aggregation of MAbs. Conjugates were prepared with antimelanoma MAb 2.1 containing up to 18.9 SnCe6 molecules per MAb. Under neutral conditions, no hydrolysis of the hydrazone bond between the MAb and the dextran carrier could be detected, and the hydrazone was not stabilized by reduction with NaCNBH3 or NaBH4. Analysis of the purified immunoconjugates showed that approximately two dextran carrier chains were attached to a MAb regardless of the number of SnCe6 molecules linked to a dextran carrier. Site-specific covalent attachment of the SnCe6-dextran chains to the MAb was confirmed by SDS-PAGE. HPLC analysis of the conjugates gave a single species eluting in the range of 200-240 kDa. As determined by a competitive inhibition radioimmunoassay using viable SK-MEL-2 human malignant melanoma cells, the conjugates showed excellent retention of antigen-binding activity relative to unconjugated MAb.     

纳米材料治疗具核梭杆菌促进的结直肠癌研究进展

具核梭杆菌(Fusobacterium nucleatum,Fn)是一种口腔厌氧菌,最近被发现在人类结直肠癌(colorectal cancer,CRC)细胞表面聚集,其富集程度与癌症治疗预后呈高度负相关。大量研究表明,Fn参与CRC的发生与发展过程,Fn与肿瘤微环境中多种组分相互作用从而增强肿瘤的耐药性。近年来,开始有研究利用纳米材料抑制Fn在肿瘤部位的增殖或通过直接靶向Fn治疗CRC。因此,本综述一方面将对近年来Fn在CRC中促肿瘤的机制进行梳理总结,另一方面将归纳整理不同纳米材料应用于Fn相关CRC治疗的最新研究进展,最后对纳米材料在Fn介导的CRC治疗中的应用前景进行了展望。     

Inhibition of cell proliferation with antibody-targeted liposomes containing methotrexate-gamma-dimyristoylphosphatidylethanolamine

We have prepared liposomes containing methotrexate-gamma-dimyristoylphosphatidylethanolamine (MTX-DMPE liposomes), to which protein A was covalently coupled, permitting specific association of these liposomes in vitro with murine cells preincubated with relevant protein A-binding monoclonal antibodies. In the absence of antibody the presence of externally-oriented methotrexate (MTX) in MTX-DMPE liposomes did not result in greater binding to cells than liposomes made without MTX-gamma-DMPE. Derivation of methotrexate with phospholipid permits enhanced drug-liposome association. These liposomes are more resistant than conventional liposomes to repeated cycles of freezing and thawing. MTX-DMPE liposomes are comparable to antibody-targeted liposomes made with encapsulated water-soluble methotrexate both with respect to specific binding to target cells and drug effect. The inhibitory effects of MTX-liposomes, as well as free MTX, were reversible by either thiamin pyrophosphate (Tpp) or N5-formyltetrahydrofolate (F-THF), while the effects of MTX-DMPE liposomes were reversed only by N5-formyltetrahydrofolate. This suggests that the toxicity of non-targeted MTX-liposomes may be due to leakage of the encapsulated MTX. The absence of an effect of thiamin pyrophosphate on non-targeted MTX-DMPE liposomes indicates that they do not enter into the cell via the normal folate transport system.     

Utilization of chromosomal markers in cancer research]

The mouse is an unsuitable species for cytogenetical studies to the extent that it has 40 acrocentric chromosomes and the only criterion which could be used to differentiate them is size. We envisaged using in the case of cell grafts donors or recipients of different sex. This technique has, however, been used to a limited extent. Among the other markers which have been utilized, T6T6 of CBA mice must be mentioned. The discovery in 1966 by Léonard and Dekundt of the presence in AKR mice of fusions of the Robertson type (between chromosomes 6 and 15) has generated new interest in experimental work based on the utilisation of chromosome markers. Being interested in the mechanisms of radio-induced leukemia, the authors described how they have introduced the chromosome marker of AKR mice into the C57B1 strain which is very sensitive to the induction of radio-induced leukemias.     

Superantigen-staphylococal-enterotoxin-A-dependent and antibody-targeted lysis of GD2-positive neuroblastoma cells

 Superantigens such as the staphylococcal enterotoxin A (SEA) are among the most potent T cell activators known. They bind to major histocompatibility complex (MHC) class II molecules and interact with T cells depending on their T cell receptor (TCR) Vβ expression. Superantigens also induce a variety of cytokines and trigger a direct cytotoxic effect against MHC-class-II-positive target cells. In order to extend superantigen-dependent cell-mediated cytotoxicity (SDCC) to MHC-class-II-negative neuroblastoma cells, SEA was linked to the anti-ganglioside GD₂ human/mouse chimeric monoclonal antibody (mAb) ch14.18. Ganglioside GD₂ is expressed on most tumours of neuroectodermal origin but is expressed to a lesser extent on normal tissues. The linkage of ch14.18 to SEA was achieved either with a protein-A–SEA fusion protein or by chemical coupling. Both constructs induced T-cell-mediated cytotoxicity towards GD₂-positive neuroblastoma cells in an effector-to-target(E:T)-ratio-and dose-dependent manner in vitro. To reduce the MHC class II affinity of SEA, a point mutation was introduced in the SEA gene (SEAm9) that resulted in 1000-fold less T cell killing of MHC-class-II-expressing cells as compared to native SEA. However, a protein-A–SEAm9 fusion protein mediated cytotoxicity similar to that of protein-A–SEA on ch14.18-coated, MHC-class-II-negative neuroblastoma cells. Taken together, these findings suggest that superantigen-dependent and monoclonal-antibody-targeted lysis may be a potent novel approach for neuroblastoma therapy. Received: 15 March 1995 / Accepted: 22 May 1995     

Progress and clinical potential of antibody-targeted therapy for arthritic damage

Introduction: The advent of biologic drugs like infliximab, Etanercept, rituximab and tocilizumab has greatly improved the treatment of rheumatoid arthritis, however, increased risk of infection and high cost still remain unmet needs. A new generation of targeted therapeutics is being developed to target payload drug specifically to arthritic tissue; to concentrate the drug in the disease area and limit the off target systemic exposure. This might also reduce total effective dose.

Areas covered: This article summarizes the properties and progress of targeted therapies that have been published on PubMed, and addresses their clinical potential.

Expert commentary: Incredible progress with targeted therapies has already been made in the short time since the principle was first proven in animal models in 2007 when targeting payload drug to overexpressed oncofetal domain of fibronectin in inflamed arthritic joints.