Regulation of apoptosis by type III interferons

Comparison of the regulation of β-catenin signaling by type I, type II and type III interferons in hepatocellular carcinoma cells

Background/Objective

IFNs are a group of cytokines that possess potent antiviral and antitumor activities, while β-catenin pathway is a proliferative pathway involved in carcinogenesis. Interaction between these two pathways has not been well elaborated in hepatocellular carcinoma (HCC).

Methods

HCC cell lines, HepG2 and Huh7, were used in this study. β-catenin protein levels and corresponding signaling activities were observed by flow cytometry and luciferase assay, respectively. Cell proliferation was quantified by counting viable cells under microscope, and apoptosis by TUNEL assay. DKK1 and GSK3β levels were determined by flow cytometry. Secreted DKK1 was tested by ELISA. FLUD, S3I and aDKK1 were used to inhibit STAT1, STAT3 and DKK1 activities, respectively.

Results

Our findings show that all three types of IFNs, IFNα, IFNγ and IFNλ, are capable of inhibiting β-catenin signaling activity in HepG2 and Huh7 cells, where IFNγ was the strongest (p<0.05). They expressed suppression of cellular proliferation and induced apoptosis. IFNγ expressed greater induction ability when compared to IFNα and IFNλ (p<0.05). All tested IFNs could induce DKK1 activation but not GSK3β in HepG2 and Huh7 cells. IFNs induced STAT1 and STAT3 activation but by using specific inhibitors, we found that only STAT3 is vital for IFN-induced DKK1 activation and apoptosis. In addition, DKK1 inhibitor blocked IFN-induced apoptosis. The pattern of STAT3 activation by different IFNs is found consistent with the levels of apoptosis with the corresponding IFNs (p<0.05).

Conclusions

In hepatocellular carcinoma, all three types of IFNs are found to induce apoptosis by inhibiting β-catenin signaling pathway via a STAT3- and DKK1-dependent pathway. This finding points to a cross-talk between different IFN types and β-catenin signaling pathways which might be carrying a biological effect not only on HCC, but also on processes where the two pathways bridge.

Analysis of genetic variants of class II cytokine and their receptor genes in psoriasis patients of two ethnic groups from the Volga-Ural region of Russia

BACKGROUND

The molecular basis of pathogenesis of psoriasis remains unclear, but one unifying hypothesis of disease aetiology is the cytokine network model. The class II cytokines (CF2) and their receptors (CRF2) are all involved in the inflammatory processes and single nucleotide polymorphisms (SNPs) in respective genes have been associated with psoriasis in a previous study of the Estonian population.

OBJECTIVE

We performed a replication study of 47 SNPs in CF2 and CRF2 genes in independent cohorts of psoriasis patients of two ethnic groups (Russians and Bashkirs) from the Volga-Ural region of Russia.

METHODS

DNA was obtained from 395 psoriasis patients of two ethnic groups from the Volga-Ural region of Russia and 476 ethnically matched controls. 47 SNPs in the loci of the genes encoding Class II cytokines and their receptors were selected by SNPbrowser version 3.5. Genotyping was performed using the SNPlex™ (Applied Biosystems) platform.

RESULTS

The genetic variant rs30461 previously associated in original case-control study in Estonians, was also associated in Russians (corrected P-value (Pc=0.008, OR=0.44), but did not reach statistical significance in the Bashkir population. Additionally, the haplotype analysis provided that CC haplotype formed by the SNPs rs30461 and rs955155 had a protective effect in Russians (Pc=0.0024, OR=0.44), supporting the involvement of this locus in the protection against psoriasis. Combined meta-analysis of three populations, including 943 psoriasis patients and 812 healthy controls, showed that the IL29 rs30461 C-allele was not associated with decreased risk of psoriasis (P=0.165, OR=0.68). Moreover, stratification of studies by ethnicity revealed a significant association in the European cohort (P=9.506E-006, OR=0.53).

CONCLUSION

Therefore, there is no overall evidence of association between psoriasis and SNP rs30461 of the IL29 gene, but there is some evidence to suggest that an association exists in Europeans. However, this current concept should be considered as preliminary and the results need to be confirmed in future independent studies.

Type III interferon induces apoptosis in human lung cancer cells

The apoptotic effects of interferon lambdas (IFNλs) have been described in several types of cancers. However, their effects on human lung cancer cells and the mechanisms are elusive. In addition, the interaction between IFNλs and other interferons remains unclear. The interplay between IFNα and IFNλ has been reported. However, although IFNγ is a well-known regulatory interferon, the mechanisms through which it regulates IFNλs in lung cancer cells are unknown. These issues are critical for the application of IFNλs in lung cancer therapy. In this study, we used A549, a cell line derived from a human lung carcinoma, to characterize the antiproliferative and apoptotic effects of IFNλs on lung cancer, and the interplay between IFNγ and IFNλ. Because overexpression of full-length ectopic IFNλR1 led to cell death, we generated A549 cells stably expressing a chimeric receptor (10R1/λR1), which is composed of the extracellular domain of IL-10 receptor (IL10R1) fused in tandem to the transmembrane and intracellular domains of the IFNλ receptor (IFNλR1). By comparing with A549 cells stably expressing its cognate vector, we demonstrated that IL-10 stimulation triggered the intracellular IFNλ signaling via 10R1/λR1 receptor. By using A549 cells expressing 10R1/λR1, we report that the IFNλR1 chain of IFNλ receptor possesses an intrinsic ability to trigger apoptosis in human lung cancer cells. Although it did not suppress cell proliferation, IFNλ signaling via 10R1/λR1 receptor induced cell cycle arrest, externalization of phosphatidylserine, DNA fragmentation, activation of caspase-3, caspase-8 and caspase-9. However, the caspase inhibitor Z-VAD-FMK did not prevent apoptosis. In addition, the extent of induced apoptosis correlate with the expression levels of the IFNλ receptor and the levels of STAT1 activation. Lastly, we demonstrated that IFNγ sensitized A549 cells to IFNλ-induced apoptosis, via upregulation of IFNλR1. These data indicate the potential of IFNλ, alone or in combination with IFNγ, in the treatment of human lung carcinoma.

High levels of β-catenin promote IFNγ-induced apoptosis in hepatocellular carcinoma cells

β-catenin is a multifunctional protein that is involved in cellular structure and the Wnt/β-catenin signaling pathway. Wnt/β-catenin signaling is believed to be an inducer of cell proliferation in different tumors. However, in certain physiological contexts β-catenin also promotes apoptosis. High levels of β-catenin are found in a number of cancer cell types. Recent studies have shown that β-catenin may be correlated with carcinogenesis. Its effects and interaction with interferon (IFN)γ signaling in hepatocellular carcinoma (HCC) cells remains unknown. In the present study, high levels of β-catenin did not induce antiproliferative effects or apoptosis and did not lead to changes in the levels of caspases or activated STATs. However, high levels of β-catenin did cause positive p53 accumulation and Bcl-XL downregulation in HepG2 cells, a HCC cell line. When treated with IFNγ, apoptosis was induced more rapidly compared with cells with low β-catenin levels (P<0.05), whereas caspases 3, 8 and 9 were markedly activated. The caspase inhibitor Z-VAD-FMK and the STAT3 inhibitor blocked this IFNγ-induced apoptosis. Therefore, we report that high levels of β-catenin promote IFNγ-induced apoptosis in HCC in a caspase- and STAT3-dependent manner, and facilitate the activation of executor caspases, possibly via regulation of p53 and Bcl-XL levels. These findings may provide foundations for the development of new IFN-based therapies against liver cancer.

Activation of type I and III interferon signalling pathways occurs in lung epithelial cells infected with low pathogenic avian influenza viruses

The host response to the low pathogenic avian influenza (LPAI) H5N2, H5N3 and H9N2 viruses were examined in A549, MDCK, and CEF cells using a systems-based approach. The H5N2 and H5N3 viruses replicated efficiently in A549 and MDCK cells, while the H9N2 virus replicated least efficiently in these cell types. However, all LPAI viruses exhibited similar and higher replication efficiencies in CEF cells. A comparison of the host responses of these viruses and the H1N1/WSN virus and low passage pH1N1 clinical isolates was performed in A549 cells. The H9N2 and H5N2 virus subtypes exhibited a robust induction of Type I and Type III interferon (IFN) expression, sustained STAT1 activation from between 3 and 6 hpi, which correlated with large increases in IFN-stimulated gene (ISG) expression by 10 hpi. In contrast, cells infected with the pH1N1 or H1N1/WSN virus showed only small increases in Type III IFN signalling, low levels of ISG expression, and down-regulated expression of the IFN type I receptor. JNK activation and increased expression of the pro-apoptotic XAF1 protein was observed in A549 cells infected with all viruses except the H1N1/WSN virus, while MAPK p38 activation was only observed in cells infected with the pH1N1 and the H5 virus subtypes. No IFN expression and low ISG expression levels were generally observed in CEF cells infected with either AIV, while increased IFN and ISG expression was observed in response to the H1N1/WSN infection. These data suggest differences in the replication characteristics and antivirus signalling responses both among the different LPAI viruses, and between these viruses and the H1N1 viruses examined. These virus-specific differences in host cell signalling highlight the importance of examining the host response to avian influenza viruses that have not been extensively adapted to mammalian tissue culture.

Profiling the expression of interleukin (IL)-28 and IL-28 receptor α in systemic lupus erythematosus patients

BACKGROUND

  Interleukin (IL)-28 is an interferon-λ-family member involved in immunity against viral infection and tumour. We here determined the expression profiles of IL-28 and IL-28 receptor α (IL-28RA) in patients with systemic lupus erythematosus (SLE) to evaluate the possibility that IL-28 is linked to the pathogenesis of SLE.

MATERIALS AND METHODS

  The serum IL-28 protein levels were determined by ELISA, and the IL-28 and IL-28RA transcript levels in peripheral blood mononuclear cells (PBMCs) and peripheral blood T cells were determined by RT-PCR. The levels in patients with SLE with the active disease activity were statistically compared with those in normal controls.

RESULTS

IL-28 protein in sera and IL-28 transcripts in PBMCs and unactivated T cells were detectable only in some individuals, and IL-28 transcripts in T cells were induced by cell activation with anti-CD2, anti-CD3 and anti-CD28 antibodies. However, compared with normal controls, patients with SLE more frequently had detectable IL-28 protein in serum and had the higher IL-28 transcript levels in activated CD4(+) T cells, but not activated CD8(+) T cells. Two IL-28RA transcripts isoforms were detected in PBMCs and T cells, and their levels in patients with SLE were comparable with those in normal controls.

CONCLUSIONS

  The expression of IL-28, a T-cell autocrine factor, is dysregulated in patients with SLE, supporting the possibility that IL-28 may contribute to some of the SLE pathogenesis.

Interferon lambda: a new sword in cancer immunotherapy

The discovery of the interferon-lambda (IFN-λ) family has considerably contributed to our understanding of the role of interferon not only in viral infections but also in cancer. IFN-λ proteins belong to the new type III IFN group. Type III IFN is structurally similar to type II IFN (IFN-γ) but functionally identical to type I IFN (IFN-α/β). However, in contrast to type I or type II IFNs, the response to type III IFN is highly cell-type specific. Only epithelial-like cells and to a lesser extent some immune cells respond to IFN-λ. This particular pattern of response is controlled by the differential expression of the IFN-λ receptor, which, in contrast to IFN-α, should result in limited side effects in patients. Recently, we and other groups have shown in several animal models a potent antitumor role of IFN-λ that will open a new challenging era for the current IFN therapy.

Adenoviruses-mediated transduction of human oesophageal carcinoma cells with the interferon-λ genes produced anti-tumour effects

BACKGROUND

Interferon-λs (IFN-λs) are novel cytokines with multiple functions, like IFN-α and -β. We examined possible anti-tumour effects produced by adenoviruses bearing the IFN-λ1 or -λ2 gene (Ad/IFN-λ) with the type-35 fibre-knob structure.

METHODS

Proliferation of oesophageal carcinoma cells transduced with Ad/IFN-λ and mechanisms of the inhibited growth were investigated.

RESULTS

Transduction with Ad/IFN-λ upregulated the expression of the class I antigens of the major histocompatibility complexes and induced the growth suppression. Increased sub-G1 populations and the cleavage of caspase-3 and poly (ADP-ribose) polymerase were detected in IFN-λ-sensitive YES-2 and T.Tn cells. The cell death was accompanied by cytoplasmic cytochrome C and increased cleaved caspase-9 and Bax expression, suggesting mitochondria-mediated apoptosis. Adenovirus/IFN-λ-infected YES-2 cells subsequently reduced the tumourigenicity. Adenovirus/IFN-λ-infected fibroblasts, negative for the IFN-λ receptors, induced death of YES-2 or T.Tn cells that were co-cultured. Inoculation of YES-2 cells in nude mice, when mixed with the Ad/IFN-λ-infected fibroblasts, resulted in retardation of the tumour growth. The growth suppression was not linked with upregulated CD69 expression on natural killer cells or increased numbers of CD31-positive cells.

CONCLUSION

Adenovirus/IFN-λ induced apoptosis, and fibroblast-mediated delivery of IFN-λs is a potential cancer treatment by inducing direct cell death of the target carcinoma.

The DNA damage response induces IFN

This study reveals a new complexity in the cellular response to DNA damage: activation of IFN signaling. The DNA damage response involves the rapid recruitment of repair enzymes and the activation of signal transducers that regulate cell-cycle checkpoints and cell survival. To understand the link between DNA damage and the innate cellular defense that occurs in response to many viral infections, we evaluated the effects of agents such as etoposide that promote dsDNA breaks. Treatment of human cells with etoposide led to the induction of IFN-stimulated genes and the IFN-α and IFN-λ genes. NF-κB, known to be activated in response to DNA damage, was shown to be a key regulator of this IFN gene induction. Expression of an NF-κB subunit, p65/RelA, was sufficient for induction of the human IFN-λ1 gene. In addition, NF-κB was required for the induction of IFN regulatory factor-1 and -7 that are able to stimulate expression of the IFN-α and IFN-λ genes. Cells that lack the NF-κB essential modulator lack the ability to induce the IFN genes following DNA damage. Breaks in DNA are generated during normal physiological processes of replication, transcription, and recombination, as well as by external genotoxic agents or infectious agents. The significant finding of IFN production as a stress response to DNA damage provides a new perspective on the role of IFN signaling.

IFN-λs

For decades, type I IFNs have been considered indispensable and unique antiviral mediators for the activation of rapid innate antiviral protection. However, the recent discovery of type III IFNs is challenging this paradigm. Since their identification in 2002/2003 by two independent groups, type III IFNs or IFN-λs, also known as IL-28/29, have been the subject of increased study with consequent recognition of their importance in virology and immunology. Initial reports suggested that IFN-λs functionally resemble type I IFNs. Although IFN-λs and classical type I IFNs (IFN-α/β) utilize distinct receptor complexes for signaling, both types of IFNs activate similar intracellular signaling pathways and biological activities, including the ability to induce antiviral state in cells, and both type I and type III IFNs are induced by viral infection. However, different antiviral potency, pattern of their induction and differential tissue expression of their corresponding receptor subunits suggest that the type I and type III IFN antiviral systems do not merely duplicate each other. Recent studies have started to reveal unique biological activities of IFN-λs in and beyond innate antiviral immunity.

Antitumor activities of recombinant human interferon (IFN)-λ1 in vitro and in xenograft models in vivo for colon cancer

Interferon (IFN)-λ1, as a newly identified IFN, interacts with the structurally unique IFN-λ1 receptor complex and exhibits antiviral and antiproliferation effects. The major focus of our work was to study the antitumor activities of recombinant human IFN-λ1 (rhIFN-λ1) in vivo and in vitro. The MTT analysis showed that rhIFN-λ1 inhibited the proliferation of HCT116 cells in a dose-dependent manner, but with a less efficacy in HT29 cells than HCT116 cells. IFN-λ1 also activated the STATs and induced apoptosis in both types of cells. In the in vivo study, we found that rhIFN-λ1 suppressed tumor growth in a dose-dependent fashion, with an inhibition rate of 52% of HCT116 (P<0.01) and 56% of HT29 (P<0.01). These results indicate that rhIFN-λ1 could be a new potential IFN reagent for cancer therapy.

IL-28B rs12979860 C/T allele distribution in patients with liver cirrhosis: role in the course of chronic viral hepatitis and the development of HCC

BACKGROUND & AIMS

A single nucleotide polymorphism (rs12979860 C/T) 3kb upstream of the interleukin 28B (IL-28B) gene was shown to be associated with hepatitis C clearance. We verified whether this association also translates into a different genotype distribution at the end of the disease trajectory.

METHODS

A RFLP-PCR technique was used to genotype 412 patients with cirrhosis due to hepatitis C (n=199), hepatitis B (n=75), alcohol (n=110), and other causes (n=28), of whom 256 underwent liver transplantation (OLT). Hepatocellular carcinoma (HCC) was demonstrated in the native liver of 85 OLT patients, 52 with viral cirrhosis, and 33 with non-viral cirrhosis respectively. A group of 292 patients (235 HCV and 57 HBV positive) with mild chronic hepatitis and 344 healthy subjects served as controls.

RESULTS

A significant difference (p=0.0005) was observed in IL-28B rs12979860 genotype frequencies between patients with viral cirrhosis (C/C=99, C/T=137, T/T=38) and those with non-viral cirrhosis (C/C=72, C/T=58, T/T=8). Patients with HCV related cirrhosis carried more frequently the T/T genotype in comparison to mild hepatitis C or HBV-related cirrhosis. IL-28B rs12979860 genotype frequencies were C/C=23, C/T=50, T/T=12 among OLT patients with cirrhosis complicated by HCC, and C/C=79, C/T=78, T/T=14 among patients with cirrhosis not complicated by HCC (p<0.005).

CONCLUSIONS

IL-28B rs12979860 C/T polymorphism T allele is more prevalent in patients with viral cirrhosis due to HCV in comparison to other aetiologies and to patients with mild chronic hepatitis C. Among OLT patients, carriage of this allele seems to augment the risk of developing HCC.

Interferon-lambda: a new addition to an old family

The discovery and initial description of the interferon-lambda (IFN-lambda) family in early 2003 opened an exciting new chapter in the field of IFN research. There are 3 IFN-lambda genes that encode 3 distinct but highly related proteins denoted IFN-lambda1, -lambda2, and -lambda3. These proteins are also known as interleukin-29 (IL-29), IL-28A, and IL-28B, respectively. Collectively, these 3 cytokines comprise the type III subset of IFNs. They are distinct from both type I and type II IFNs for a number of reasons, including the fact that they signal through a heterodimeric receptor complex that is different from the receptors used by type I or type II IFNs. Although type I IFNs (IFN-alpha/beta) and type III IFNs (IFN-lambda) signal via distinct receptor complexes, they activate the same intracellular signaling pathway and many of the same biological activities, including antiviral activity, in a wide variety of target cells. Consistent with their antiviral activity, expression of the IFN-lambda genes and their corresponding proteins is inducible by infection with many types of viruses. Therefore, expression of the type III IFNs (IFN-lambdas) and their primary biological activity are very similar to the type I IFNs. However, unlike IFN-alpha receptors which are broadly expressed on most cell types, including leukocytes, IFN-lambda receptors are largely restricted to cells of epithelial origin. The potential clinical importance of IFN-lambda as a novel antiviral therapeutic agent is already apparent. In addition, preclinical studies by several groups indicate that IFN-lambda may also be useful as a potential therapeutic agent for other clinical indications, including certain types of cancer.

Regulatory effects of ribosomal S6 kinase 1 (RSK1) in IFNλ signaling

Although the mechanisms of generation of signals that control transcriptional activation of Type III IFN (IFNλ)-regulated genes have been identified, very little is known about the mechanisms by which the IFNλ receptor generates signals for mRNA translation of IFNλ-activated genes. We provide evidence that IFNλ activates the p90 ribosomal protein S6 kinase 1 (RSK1) and its downstream effector, initiation factor eIF4B. Prior to its engagement by the IFNλ receptor, the non-active form of RSK1 is present in a complex with the translational repressor 4E-BP1 in IFNλ-sensitive cells. IFNλ-inducible phosphorylation/activation of RSK1 results in its dissociation from 4E-BP1 at the same time that 4E-BP1 dissociates from eIF4E to allow formation of eIF4F and initiation of cap-dependent translation. Our studies demonstrate that such IFNλ-dependent engagement of RSK1 is essential for up-regulation of p21(WAF1/CIP1) expression, suggesting a mechanism for generation of growth-inhibitory responses. Altogether, our data provide evidence for a critical role for the activated RSK1 in IFNλ signaling.

The interferon stimulated gene 54 promotes apoptosis

The ability of interferons (IFNs) to inhibit viral replication and cellular proliferation is well established, but the specific contribution of each IFN-stimulated gene (ISG) to these biological responses remains to be completely understood. In this report we demonstrate that ISG54, also known as IFN-induced protein with tetratricopeptide repeats 2 (IFIT2), is a mediator of apoptosis. Expression of ISG54, independent of IFN stimulation, elicits apoptotic cell death. Cell death and apoptosis were quantified by propidium iodide uptake and annexin-V staining, respectively. The activation of caspase-3, a key mediator of the execution phase of apoptosis, was clearly apparent in cells expressing ISG54. The anti-apoptotic B cell lymphoma-xl (Bcl-xl) protein inhibited the apoptotic effects of ISG54 as did the anti-apoptotic adenoviral E1B-19K protein. In addition, ISG54 was not able to promote cell death in the absence of pro-apoptotic Bcl family members, Bax and Bak. Analyses of binding partners of ISG54 revealed association with two homologous proteins, ISG56/IFIT1 and ISG60/IFIT3. In addition, ISG60 binding negatively regulates the apoptotic effects of ISG54. The results reveal a previously unidentified role of ISG54 in the induction of apoptosis via a mitochondrial pathway and shed new light on the mechanism by which IFN elicits anti-viral and anti-cancer effects.

Crystal structure of human interferon-λ1 in complex with its high-affinity receptor interferon-λR1

Interferon (IFN)-λ1 [also known as interleukin (IL)-29] belongs to the recently discovered group of type III IFNs. All type III IFNs initiate signaling processes through formation of specific heterodimeric receptor complexes consisting of IFN-λR1 and IL-10R2. We have determined the structure of human IFN-λ1 complexed with human IFN-λR1, a receptor unique to type III IFNs. The overall structure of IFN-λ1 is topologically similar to the structure of IL-10 and other members of the IL-10 family of cytokines. IFN-λR1 consists of two distinct domains having fibronectin type III topology. The ligand-receptor interface includes helix A, loop AB, and helix F on the IFN site, as well as loops primarily from the N-terminal domain and inter-domain hinge region of IFN-λR1. Composition and architecture of the interface that includes only a few direct hydrogen bonds support an idea that long-range ionic interactions between ligand and receptor govern the process of initial recognition of the molecules while hydrophobic interactions finalize it.

Interferon-lambda as a potential therapeutic agent in cancer treatment

The discovery that type I interferon (IFN-alpha/beta) inhibited tumor cell growth was welcomed initially with great excitement as it rapidly became a U.S. Food and Drug Administration-approved drug to treat several forms of cancer. In time, this enthusiasm diminished as severe toxicity associated with IFN-alpha administration, resistance to the therapy, or less than optimal responses became evident in cancer patients, thus restricting its clinical use and reducing its potential as an anticancer drug. The recent discovery of a third type of IFN [IFN-lambda/interleukin (IL)-29/IL-28], which shares the same biological properties of type I IFNs, opens the door for evaluating the therapeutic potential of IFN-lambda as it uses a distinct receptor complex whose expression, unlike type I IFN receptors, is restricted to cells of specific lineage. It is unclear whether the mechanism by which type III IFNs restrict tumor cell proliferation is different or the same from the one utilized by type I IFN. Nevertheless, accumulating evidence as described in this review suggests that, in contrast to IFN-alpha therapy, IFN-lambda therapy could be less toxic and suitable for certain types of malignancies as not all cells are responsive to this cytokine.

The lambda interferons: guardians of the immune-epithelial interface and the T-helper 2 response

The type-III interferons (IFNs) are the most recently discovered IFNs in the human immune system and have important, but as yet poorly characterized, functions in innate and adaptive immunity that complement their antiviral functions. It is now becoming clear that these type-III IFNs have a functional niche where epithelial surfaces interact with the adaptive immune system, that their antiviral capability is not as highly developed as that of the type-I IFNs, and that they have their own profile of immunomodulatory functions; specifically, they are key modulators of the T-helper (Th)2 response.

The effect of IL-28A on human cord blood CD4+ T cells

BACKGROUND AND AIM

The utilization of umbilical cord blood transplantation (UCBT) has been increasing because of the potential advantage of rapid accessibility and the lesser risk of graft-versus-host disease (GVHD), thus allowing less strict HLA matching. IL-28A, also known as IFN-lambda2, has been regarded as a member of a new cytokine family that shares some features with type I interferon (IFN) and was shown to have antiviral activity. The aim of this study was to identify biological activity of IL-28 on cord blood CD4(+) T cells.

MATERIALS AND METHODS

In this study, we cultured CD4(+) T cells with IL-28A (20 ng/ml), IL-2 (20 ng/ml) and 5microg/ml MACS Anti-Biotin MACSiBead Particles (bead-to-cell ratio 1:2) for 2 weeks.

RESULTS

Flow cytometry analyses showed that IL-28A cannot be effective on CD25 and Foxp3 expression on cord blood CD4(+) T cells, and it is not involved in proliferation of these cells. Treg suppression assay also showed that this cytokine cannot induce production of regulatory T cells.

CONCLUSION

We showed that IL-28A is not involved in expression of CD25 and Foxp3 markers and proliferation of CD4(+)CD25(-) T cells, and that our findings also suggest that induction of Foxp3 in T cells activated by anti-CD3/anti-CD28 does not result in the regulatory activity in these cells.

Lethal dissemination of H5N1 influenza virus is associated with dysregulation of inflammation and lipoxin signaling in a mouse model of infection

Periodic outbreaks of highly pathogenic avian H5N1 influenza viruses and the current H1N1 pandemic highlight the need for a more detailed understanding of influenza virus pathogenesis. To investigate the host transcriptional response induced by pathogenic influenza viruses, we used a functional-genomics approach to compare gene expression profiles in lungs from 129S6/SvEv mice infected with either the fully reconstructed H1N1 1918 pandemic virus (1918) or the highly pathogenic avian H5N1 virus Vietnam/1203/04 (VN/1203). Although the viruses reached similar titers in the lung and caused lethal infections, the mean time of death was 6 days for VN/1203-infected animals and 9 days for mice infected with the 1918 virus. VN/1203-infected animals also exhibited an earlier and more potent inflammatory response. This response included induction of genes encoding components of the inflammasome. VN/1203 was also able to disseminate to multiple organs, including the brain, which correlated with changes in the expression of genes associated with hematological functions and lipoxin biogenesis and signaling. Both viruses elicited expression of type I interferon (IFN)-regulated genes in wild-type mice and to a lesser extent in mice lacking the type I IFN receptor, suggesting alternative or redundant pathways for IFN signaling. Our findings suggest that VN/1203 is more pathogenic in mice as a consequence of several factors, including the early and sustained induction of the inflammatory response, the additive or synergistic effects of upregulated components of the immune response, and inhibition of lipoxin-mediated anti-inflammatory responses, which correlated with the ability of VN/1203 to disseminate to extrapulmonary organs.

Lambda Interferons: New Cytokines with Old Functions

Interferon lambda (IFN-λ) is a member of the class II cytokine family, and like the other members of this family, they are small helical proteins. Since their discovery significant efforts have been made to determine their role in innate and adaptive immunity. Their strong antiviral activity, both in vitro and in vivo, has firmly established their interferon status. However, in contrast to type I interferon, only a very limited subset of cells/tissues responds to interferon lambda. In addition to inducing an antiviral state in responsive cells, recent data suggest that IFN-l plays a role in shaping the adaptive immune response. However, the data is not in complete agreement regarding the effect of IFN-λ on the adaptive immune system. Recently IFN-l has entered clinical trials against hepatitis C Virus and IFN-l is a promising future therapeutic, against different viruses replicating in responsive tissues, like that of the airway epithelia. In this review we describe the knowledge acquired during the past six years about the structure and function of interferon lambda.

Interferon-lambda induces G1 phase arrest or apoptosis in oesophageal carcinoma cells and produces anti-tumour effects in combination with anti-cancer agents

Signal pathways of novel type III interferons (IFN-lambdas) are similar to those of type I IFNs (IFN-alpha/beta) but their distinct functions have not been well characterised. We examined the growth suppressive activity of IFN-lambda1 with nine human oesophageal carcinoma cell lines expressing the IFN-lambda receptor complexes. Among them, three lines but not others showed IFN-lambda1-mediated growth suppression by inducing G1 phase arrest or apoptosis. The G1 phase arrest was accompanied by the up-regulation of p21 and dephosphorylation of retinoblastoma (Rb), and the apoptosis was evidenced by cleavage of caspase-3 and poly (ADP-ribose) polymerase (PARP). Similar but not identical susceptibility was found in IFN-alpha-treated oesophageal carcinoma cells. Despite the differential suppressive responses among the cells, all the cells increased the expression of the myxovirus resistance A (MxA) and 2',5'-oligoadenylate synthetase (2',5'-OAS) genes and class I antigens of the major histocompatibility complexes (MHC) with IFN-lambda1 treatment. Fibroblasts and mesenchymal stem cells, positive for IFN-alpha receptor (IFNAR), lacked one of the IFN-lambda receptor complexes and Het-1A, immortalised oesophageal epithelium cells, were insensible to the IFN-lambda1-induced growth suppression. IFN-lambda1 produced combinatory anti-tumour effects with chemotherapeutic agents, cisplatin (CDDP) and 5-fluorouracil (5-FU), in IFN-lambda1-sensitive oesophageal carcinoma cells but not in normal or Het-1A cells, while IFN-alpha achieved the combinatory suppressive effects to normal cells. These data collectively show that IFN-lambda1 responsiveness is tissue-specific due to the restricted receptors expression and is diversified even among cells of the same lineage, and suggest that IFN-lambda1 is a potential therapeutic agent for oesophageal carcinoma without damaging surrounding tissues.

Type I interferon drives tumor necrosis factor-induced lethal shock

Tumor necrosis factor (TNF) is reputed to have very powerful antitumor effects, but it is also a strong proinflammatory cytokine. Injection of TNF in humans and mice leads to a systemic inflammatory response syndrome with major effects on liver and bowels. TNF is also a central mediator in several inflammatory diseases. We report that type I interferons (IFNs) are essential mediators of the lethal response to TNF. Mice deficient in the IFN-alpha receptor 1 (IFNAR-1) or in IFN-beta are remarkably resistant to TNF-induced hypothermia and death. After TNF injection, IFNAR-1(-/-) mice produced less IL-6, had less bowel damage, and had less apoptosis of enterocytes and hepatocytes compared with wild-type (WT) mice. Extensive gene expression analysis in livers of WT and IFNAR-1(-/-) mice revealed a large deficiency in the response to TNF in the knockout mice, especially of IFN-stimulated response element-dependent genes, many of which encode chemokines. In livers of IFNAR-1(-/-) mice, fewer infiltrating white blood cells (WBCs) were detected by immunohistochemistry. Deficiency of type I IFN signaling provided sufficient protection for potentially safer therapeutic use of TNF in tumor-bearing mice. Our data illustrate that type I IFNs act as essential mediators in TNF-induced lethal inflammatory shock, possibly by enhancing cell death and inducing chemokines and WBC infiltration in tissues.

Interferon-lambdas: the modulators of antivirus, antitumor, and immune responses

IFN-lambdas, including IFN-lambda1, IFN-lambda2, and IFN-lambda3, also known as IL-29, IL-28A, or IL-28B, are a newly described group of cytokines distantly related to the type I IFNs and IL-10 family members. The IFN-lambdaR complex consists of a unique ligand-binding chain, IFN-lambdaR1 (also designated IL-28Ralpha), and an accessory chain, IL-10R2, which is shared with receptors for IL-10-related cytokines. IFN-lambdas signal through the IFN-lambdaR and activate pathways of JAK-STATs and MAPKs to induce antiviral, antiproliferative, antitumor, and immune responses. In this review, we summarize recent findings about the biology of IFN-lambdas and their pathophysiological roles in viral infection, cancer, and immune responses of the innate and adaptive arms.