The fusion protein of IFN-α and apolipoprotein A-I crosses the blood-brain barrier by a saturable transport mechanism

Engineering interferons for cancer immunotherapy

Interferons are a family of cytokines that are famously known for their involvement in innate and adaptive immunity. Type I interferons (IFNs) exert pleiotropic effects on various immune cells and contribute to tumor-intrinsic and extrinsic mechanisms. Their pleiotropic effects and ubiquitous expression on nucleated cells have made them attractive candidates for cytokine engineering to deliver to largely immunosuppressive tumors. Type III interferons were believed to play overlapping roles with type I IFNs because they share a similar signaling pathway and induce similar transcriptional programs. However, type III IFNs are unique in their cell specific receptor expression and their antitumor activity is specific to a narrow range of cell types. Thus, type III IFN based therapies may show reduced toxic side effects compared with type I IFN based treatment. In this review, we focus on the development of IFN-based therapeutics used to treat different tumors. We highlight how the development in cytokine engineering has allowed for efficient delivery of type I and type III IFNs to tumor sites and look ahead to the obstacles that are still associated with IFN-based therapies before they can be fully and safely integrated into clinical settings.

Dynamic stress- and inflammatory-based regulation of psychiatric risk loci in human neurons

The prenatal environment can alter neurodevelopmental and clinical trajectories, markedly increasing risk for psychiatric disorders in childhood and adolescence. To understand if and how fetal exposures to stress and inflammation exacerbate manifestation of genetic risk for complex brain disorders, we report a large-scale context-dependent massively parallel reporter assay (MPRA) in human neurons designed to catalogue genotype x environment (GxE) interactions. Across 240 genome-wide association study (GWAS) loci linked to ten brain traits/disorders, the impact of hydrocortisone, interleukin 6, and interferon alpha on transcriptional activity is empirically evaluated in human induced pluripotent stem cell (hiPSC)-derived glutamatergic neurons. Of ~3,500 candidate regulatory risk elements (CREs), 11% of variants are active at baseline, whereas cue-specific CRE regulatory activity range from a high of 23% (hydrocortisone) to a low of 6% (IL-6). Cue-specific regulatory activity is driven, at least in part, by differences in transcription factor binding activity, the gene targets of which show unique enrichments for brain disorders as well as co-morbid metabolic and immune syndromes. The dynamic nature of genetic regulation informs the influence of environmental factors, reveals a mechanism underlying pleiotropy and variable penetrance, and identifies specific risk variants that confer greater disorder susceptibility after exposure to stress or inflammation. Understanding neurodevelopmental GxE interactions will inform mental health trajectories and uncover novel targets for therapeutic intervention.

Overcoming the limitations of cytokines to improve cancer therapy

Cytokines are pleiotropic soluble proteins used by immune cells to orchestrate a coordinated response against pathogens and malignancies. In cancer immunotherapy, cytokine-based drugs can be developed potentiating pro-inflammatory cytokines or blocking immunosuppressive cytokines. However, the complexity of the mechanisms of action of cytokines requires the use of biotechnological strategies to minimize systemic toxicity, while potentiating the antitumor response. Sequence mutagenesis, fusion proteins and gene therapy strategies are employed to enhance the half-life in circulation, target the desired bioactivity to the tumor microenvironment, and to optimize the therapeutic window of cytokines. In this review, we provide an overview of the different strategies currently being pursued in pre-clinical and clinical studies to make the most of cytokines for cancer immunotherapy.

Recombinant porphobilinogen deaminase targeted to the liver corrects enzymopenia in a mouse model of acute intermittent porphyria

[Figure: see text].

High yield expression, characterization, and biological activity of IFNα2-Tα1 fusion protein

The use of interferon α-2 in combination with thymosin α-1 shows higher anti-cancer effect in comparison when both are used individually because of their synergistic effects. In this study we produced an important human interferon α-2-thymosin α-1 (IFNα2-Tα1) fusion protein with probable pharmaceutical properties coupled to its high-level expression, characterization, and study of its biological activity. The IFNα2-Tα1 fusion gene was constructed by over-lap extension PCR and expressed in Escherichia coli expression system. The expression of IFNα2-Tα1 fusion protein was optimized to higher level and its maximum expression was obtained in modified terrific broth medium when lactose was used as inducer. The fusion protein was refolded into its native biologically active form with maximum yield of 83.14% followed by purification with ∼98% purity and 69% final yield. A band of purified IFNα2-Tα1 fusion protein equal to ∼23 kDa was observed on 12 % SDS-PAGE gel. The integrity of IFNα2-Tα1 fusion protein was confirmed by western blot analysis and secondary structure was assessed by CD spectroscopy. When IFNα2-Tα1 fusion protein was subjected to its biological activity analysis it was observed that it exhibits both IFNα2 & Tα1 activities as well as significantly higher anticancer activity as compared to IFNα-2 alone.

The SR-B1 Receptor as a Potential Target for Treating Glioblastoma

Purpose

The goal of these studies was to provide proof of concept for a novel targeted therapy for Glioblastoma Multiforme (GBM). Methods. These studies involve the evaluation of reconstituted high density lipoprotein (rHDL) nanoparticles (NPs) as delivery agents for the drug, mammalian Target of Rapamycin (mTOR) inhibitor Everolimus (EVR) to GBM cells. Cytotoxicity studies and assessment of downstream effects, including apoptosis, migration, and cell cycle events, were probed, in relation to the expression of scavenger receptor B type 1 (SR-B1) by GBM cells.

Results

Findings from cytotoxicity studies indicate that the rHDL/EVR formulation was 185 times more potent than free EVR against high SR-B1 expressing cell line (LN 229). Cell cycle analysis revealed that rHDL/EVR treated LN229 cells had a 5.8 times higher apoptotic cell population than those treated with EVR. The sensitivity of GBM cells to EVR treatment was strongly correlated with SR-B1 expression.

Conclusions

These studies present strong proof of concept regarding the efficacy of delivering EVR and likely other agents, via a biocompatible transport system, targeted to the SR-B1 receptor that is upregulated in most cancers, including GBM. Targeting the SR-B1 receptor could thus lead to effective personalized therapy of GBM.

Cytokines in clinical cancer immunotherapy

Cytokines are soluble proteins that mediate cell-to-cell communication. Based on the discovery of the potent anti-tumour activities of several pro-inflammatory cytokines in animal models, clinical research led to the approval of recombinant interferon-alpha and interleukin-2 for the treatment of several malignancies, even if efficacy was only modest. These early milestones in immunotherapy have been followed by the recent addition to clinical practice of antibodies that inhibit immune checkpoints, as well as chimeric antigen receptor T cells. A renewed interest in the anti-tumour properties of cytokines has led to an exponential increase in the number of clinical trials that explore the safety and efficacy of cytokine-based drugs, not only as single agents, but also in combination with other immunomodulatory drugs. These second-generation drugs under clinical development include known molecules with novel mechanisms of action, new targets, and fusion proteins that increase half-life and target cytokine activity to the tumour microenvironment or to the desired effector immune cells. In addition, the detrimental activity of immunosuppressive cytokines can be blocked by antagonistic antibodies, small molecules, cytokine traps or siRNAs. In this review, we provide an overview of the novel trends in the cytokine immunotherapy field that are yielding therapeutic agents for clinical trials.

Crucial role of the protein corona for the specific targeting of nanoparticles

AIMS

We aimed to investigate the physicochemical effects of superparamagnetic iron oxide nanoparticles (SPIONs) on the composition of the protein corona and their correspondence toxicological issues.

MATERIALS & METHODS

SPIONs of different sizes and surface charges were exposed to fetal bovine serum. The structure/composition and biological effects of the protein corona-SPION complexes were probed.

RESULTS & DISCUSSION

The affinity and level of adsorption of specific proteins is strongly dependent on the size and surface charge of the SPIONs. In vivo experiments on the mouse blood-brain barrier model revealed that nontargeted SPIONs containing specific proteins will enter the brain endothelial barrier cells.

CONCLUSION

Some commercially available nanoparticles used for target-specific applications may have unintended uptake in the body (e.g., brain tissue) with potential cytotoxity.

Liver-directed gene therapy of chronic hepadnavirus infection using interferon alpha tethered to apolipoprotein A-I

BACKGROUND & AIMS

Current hepatitis B virus (HBV) management is challenging as treatment with nucleos(t)ide analogues needs to be maintained indefinitely and because interferon (IFN)-α therapy is associated with considerable toxicity. Previously, we showed that linking IFNα to apolipoprotein A-I generates a molecule (IA) with distinct antiviral and immunostimulatory activities which lacks the hematological toxicity of IFNα.

METHODS

Here, we analyse the antiviral potential of an adeno-associated vector encoding IFNα fused to apolipoprotein A-I (AAV-IA) in comparison to a vector encoding only IFNα (AAV-IFN) in two animal models of chronic hepadnavirus infection.

RESULTS

In HBV transgenic mice, we found that both vectors induced marked reductions in serum and liver HBV DNA and in hepatic HBV RNA but AAV-IFN caused lethal pancytopenia. Woodchucks with chronic hepatitis virus (WHV) infection that were treated by intrahepatic injection of vectors encoding the woodchuck sequences (AAV-wIFN or AAV-wIA), experienced only a slight reduction of viremia which was associated with hematological toxicity and high mortality when using AAV-wIFN, while AAV-wIA was well tolerated. However, when we tested AAV-wIA or a control vector encoding woodchuck apolipoprotein A-I (AAV-wApo) in combination with entecavir, we found that AAV-wApo-treated animals exhibited an immediate rebound of viral load upon entecavir withdrawal while, in AAV-wIA-treated woodchucks, viremia and antigenemia remained at low levels for several weeks following entecavir interruption.

CONCLUSIONS

Treatment with AAV-IA is safe and elicits antiviral effects in animal models with difficult to treat chronic hepadnavirus infection. AAV-IA in combination with nucleos(t)ide analogues represents a promising approach for the treatment of HBV infection in highly viremic patients.

High-density lipoproteins and cerebrovascular integrity in Alzheimer's disease

Cerebrovascular dysfunction significantly contributes to the clinical presentation and pathoetiology of Alzheimer's disease (AD). Deposition and aggregation of β-amyloid (Aβ) within vascular smooth muscle cells leads to inflammation, oxidative stress, impaired vasorelaxation, and disruption of blood-brain barrier integrity. Midlife vascular risk factors, such as hypertension, cardiovascular disease, diabetes, and dyslipidemia, increase the relative risk for AD. These comorbidities are all characterized by low and/or dysfunctional high-density lipoproteins (HDL), which itself is a risk factor for AD. HDL performs a wide variety of critical functions in the periphery and CNS. In addition to lipid transport, HDL regulates vascular health via mediating vasorelaxation, inflammation, and oxidative stress and promotes endothelial cell survival and integrity. Here, we summarize clinical and preclinical data examining the involvement of HDL, originating from the circulation and from within the CNS, on AD and hypothesize potential synergistic actions between the two lipoprotein pools.

N-acetyl-cysteine prevents toxic oxidative effects induced by IFN-α in human neurons

Currently IFN-α is widely used for effective treatment of viral infections and several malignancies. However, IFN-α can cause neuropsychiatric disturbances and mental impairments, including fatigue, insomnia, depression, irritability and cognitive deficits. Molecular and cellular mechanisms leading to such side-effects are still poorly understood. Neurons seem to be an important target in mediating cellular effects induced by exposure to this cytokine, but so far little is known about IFN-α-induced effects on these cells. We have investigated the ability of IFN-α (2-100 ng/ml) to induce damage and toxicity to the human neuroblastoma SH-SY5Y cell line, commonly used for studying such phenomena, and the mechanisms underlying these effects. After 24 h treatment, IFN-α increased mitochondrial activity, whereas cell density was reduced in a dose- and time-dependent manner. This effect did not depend on reduced cell proliferation, but rather the activation of apoptosis, as revealed by an increased Bax:Bcl-2 mRNA ratio after 72-h IFN-α exposure. At this time-point, IFN-α also reduced the expression of the brain-derived neurotrophic factor gene, and induced an increase in reactive oxygen species (ROS). A co-treatment with N-acetyl-cysteine (NAC; 5 mm), a potent antioxidant and mitochondrial modulator, was able to counteract all of these IFN-α-induced effects. These findings demonstrated that IFN-α induces neurotoxicity and apoptosis that is, in part, very likely due to mitochondrial damages and production of ROS. We suggest that NAC, already tested for the treatment of psychiatric disorders, may be useful to prevent IFN-α-induced central side-effects in a safe and effective way.

Cytokines for the treatment of gastrointestinal cancers: clinical experience and new perspectives

INTRODUCTION

Cytokines are key mediators of the immune system and have been proposed as therapeutic agents against cancer, either as recombinant proteins, or as transgenes in gene therapy approaches. Stimulation of immune responses against cancer cells is an appealing method to treat tumors with high risk of relapse and systemic dissemination.

AREAS COVERED

We provide a critical overview of clinical trials involving the use of cytokines for the treatment of liver, colon and pancreatic cancers. Special attention has been paid to advances in the field of gene therapy and oncolytic viruses. The potential of new developments still in a pre-clinical stage is also discussed. We have revised public sources of information (PubMed, US National Institutes of Health clinical trials database) up to January 2013.

EXPERT OPINION

The complexity of the immune system and the unfavorable pharmacokinetic properties of cytokines limit the efficacy of these molecules as single agents for the treatment of cancer. Expression from gene therapy vectors, together with new methods of targeting and stabilization, may overcome these hurdles. We believe cytokines will play a crucial role as part of combined approaches, enhancing the action of adoptive cell immunotherapy, oncolytic viruses or biological therapies.