A new interferon, limitin, displays equivalent immunomodulatory and antitumor activities without myelosuppressive properties as compared with interferon-alpha

Effects of electroacupuncture combined with interleukin‑10 on chronic sinusitis in mice

Electroacupuncture (EA) has been documented as a form of therapy for chronic sinusitis (CRS). The present study aimed to assess the effects of EA combined with interleukin‑10 (IL‑10) overexpression on CRS in mice, and to investigate the associated mechanisms. A mouse model of CRS was established by the administration of ovalbumin (OVA), and overexpression of IL‑10 was induced using virus‑encoded IL‑10. The experimental groups were as follows: i) Control group; ii) OVA group; iii) OVA + EA group; iv) OVA + empty vector group; v) OVA + vector + EA group; vi) OVA + IL‑10 group; and vii) OVA + IL‑10 + EA group. Pathological changes and nasal mucus were analyzed using hematoxylin and eosin staining. Interferon‑γ (IFN‑γ) and IL‑10 were detected via reverse‑transcription quantitative PCR and western blot analyses. The pseudostratified epithelium of the mucosa of the nasal sinus was impaired following the induction of CRS. Treatment with EA and/or IL‑10 reversed the injury. Combination treatment with EA and IL‑10 induced synergistic effects. No infiltration of inflammatory cells was observed in the submucosa following EA and IL‑10 treatment. Compared with the control group, the expression of IFN‑γ and IL‑10 in the OVA group was reduced. By contrast, EA or the overexpression of IL‑10 inhibited this reduction. Furthermore, the combined application of EA and IL‑10 had a significantly more potent inhibitory effect on the reduction of IFN‑γ expression, but not IL‑10. Collectively, EA combined with IL‑10 induced specific effects on CRS in mice, likely through the upregulation of IFN‑γ and IL‑10. The current study presented mechanistic implications for the application of EA as an alternative treatment for CRS.

IFN-α in the treatment of melanoma

Among the IFNs, IFN-α2 has been the most broadly evaluated clinically. At the molecular level, IFN-α has multiple effects in a variety of malignancies that range from antiangiogenic to potent immunoregulatory, differentiation-inducing, antiproliferative, and proapoptotic effects. A multitude of IFN-α2 regimens that may be classified as low dose, intermediate dose, and high dose have been evaluated as adjuvant therapy in melanoma. A durable impact on both relapse-free and overall survival was seen only with the regimen utilizing high-dose IFN-α2b tested in the Eastern Cooperative Oncology Group and intergroup trials E1684, E1690, and E1694 as adjuvant therapy for high-risk surgically resected melanoma (stage IIB or III). Adjuvant pegylated IFN-α2b has also been evaluated at maximally tolerable doses compared with the observation group in the European Organization for Research and Treatment of Cancer trial 18991 and has shown relapse-free survival benefits in patients with microscopic nodal disease.

Inhibition of tumor cell motility by the interferon-inducible GTPase MxA

To identify pathways controlling prostate cancer metastasis we performed differential display analysis of the human prostate carcinoma cell line PC-3 and its highly metastatic derivative PC-3M. This revealed that a 78-kDa interferon-inducible GTPase, MxA, was expressed in PC-3 but not in PC-3M cells. The gene encoding MxA, MX1, is located in the region of chromosome 21 deleted as a consequence of fusion of TMPRSS2 and ERG, which has been associated with aggressive, invasive prostate cancer. Stable exogenous MxA expression inhibited in vitro motility and invasiveness of PC-3M cells. In vivo exogenous MxA expression decreased the number of hepatic metastases following intrasplenic injection. Exogenous MxA also reduced motility and invasiveness of highly metastatic LOX melanoma cells. A mutation in MxA that inactivated its GTPase reversed inhibition of motility and invasion in both tumor cell lines. Co-immunoprecipitation studies demonstrated that MxA associated with tubulin, but the GTPase-inactivating mutation blocked this association. Because MxA is a highly inducible gene, an MxA-targeted drug discovery screen was initiated by placing the MxA promoter upstream of a luciferase reporter. Examination of the NCI diversity set of small molecules revealed three hits that activated the promoter. In PC-3M cells, these drugs induced MxA protein and inhibited motility. These data demonstrate that MxA inhibits tumor cell motility and invasion, and that MxA expression can be induced by small molecules, potentially offering a new approach to the prevention and treatment of metastasis.

Directed evolution of gene-shuffled IFN-alpha molecules with activity profiles tailored for treatment of chronic viral diseases

Type I IFNs are unusually pleiotropic cytokines that bind to a single heterodimeric receptor and have potent antiviral, antiproliferative, and immune modulatory activities. The diverse effects of the type I IFNs are of differential therapeutic importance; in cancer therapy, an enhanced antiproliferative effect may be beneficial, whereas in the therapy of viral infections (such as hepatitis B and hepatitis C), the antiproliferative effects lead to dose limiting bone marrow suppression. Studies have shown that various members of the natural IFN-alpha family and engineered variants, such as IFN-con1, vary in the ratios between various IFN-mediated cellular activities. We used DNA shuffling to explore and confirm the hypothesis that one could simultaneously increase the antiviral and Th1-inducing activity and decrease the antiproliferative activity. We report IFN-alpha hybrids wherein the ratio of antiviral:antiproliferative and Th1-inducing: antiproliferative potencies are markedly increased with respsect to IFN-con1 (75- and 80-fold, respectively). A four-residue motif that overlaps with the IFNAR1 binding site and is derived by cross breeding with a pseudogene contributes significantly to this phenotype. These IFN-alphas have an activity profile that may result in an improved therapeutic index and, consequently, better clinical efficacy for the treatment of chronic viral diseases such as hepatitis B virus, human papilloma virus, HIV, or chronic hepatitis C.

IFN-zeta/ limitin: a member of type I IFN with mild lympho-myelosuppression

Interferon (IFN)-Zeta/limitin has been considered as a novel type I IFN by the Nomenclature Committee of the International Society for Interferon and Cytokine Research. IFN-Zeta/limitin shows some sequence homology with IFN-alpha and IFN-beta, has a globular structure with five alpha-helices and four loops, and recognizes IFN-alpha/beta receptor. Although IFN-zeta/limitin displays antiviral, immunomodulatory, and antitumor effects, it has much less lympho-myelosuppressive activities than IFN-alpha. Treatment of cells with type I IFNs induces and/or activates a number of molecules, which regulate cell cycle and apoptosis. It is noteworthy that IFN-zeta/limitin activates the Tyk2-Daxx and Tyk2-Crk pathways weaker than IFN-alpha. Because experiments using antisense oligonucleotides have revealed their essential role in type I IFN-related suppression of lympho-hematopoiesis, little ability of IFN-zeta/limitin to activate the Tyk2-dependent signaling pathway may explain its uniquely narrow range of biological activities. Further analysis of structure-function relationship of type I IFNs will establish an engineered cytokine with useful features of IFN-zeta/limitin.

Differential effects of a novel IFN-ζ/limitin and IFN-α on signals for Daxx induction and Crk phosphorylation that couple with growth control of megakaryocytes

OBJECTIVE

Although a novel IFN-zeta/limitin uses IFN-alpha/beta receptor, it lacks some common activities of type I IFNs. We compared effects on megakaryocyte proliferation and differentiation as well as signals for their biological activities.

MATERIALS AND METHODS

Recombinant IFN-zeta/limitin and IFN-alpha titrated with a cytopathic effect dye binding assay, were used in this study. Colony assays and serum-free suspension cultures for megakaryocytes were performed to compare their growth inhibitory effects. To analyze signals, megakaryocytes cultured in serum-free suspension cultures were stimulated and Western blotted with the indicated antibody.

RESULTS

Both IFN-zeta/limitin and IFN-alpha suppressed the proliferation of megakaryocyte progenitors without influencing their differentiation. However, much higher concentrations of IFN-zeta/limitin were required for the growth inhibition than IFN-alpha. The growth inhibition by IFN-zeta/limitin and IFN-alpha was significantly reduced when either Tyk2 or STAT1 was disrupted. In addition, the antisense oligonucleotides against Crk and Daxx, downstream molecules of Tyk2, greatly rescued the IFN-zeta/limitin- and IFN-alpha-induced reduction of megakaryocyte colony numbers. In cultured megakaryocytes, IFN-zeta/limitin induced the expression of SOCS-1 as strongly as IFN-alpha. However, IFN-zeta/limitin induced weaker phosphorylation of Crk and lower induction of Daxx than IFN-alpha.

CONCLUSIONS

Weaker signals for Crk and Daxx may participate in less megakaryocyte suppressive activity of IFN-zeta/limitin and may distinguish IFN-zeta/limitin from IFN-alpha in megakaryocytes. Our results extend the understanding about thrombocytopenia in patients with IFN-alpha treatment as well as the possibility for the clinical application of human homologue of IFN-zeta/limitin or an engineered cytokine with useful features of the IFN-zeta/limitin structure.

Interferon-3/Limitin: Novel Type I Interferon That Displays a Narrow Range of Biological Activity

Interferon zeta (IFN-zeta)/limitin has been regarded as a novel type I IFN by the Nomenclature Committee of the International Society for Interferon and Cytokine Research. IFN-zeta/limitin, which has some sequence homology with IFN-alpha and IFN-beta, has a globular structure with 5 alpha helices and 4 loops and recognizes IFN-alpha/beta receptor. Although it displays antiviral, immunomodulatory, and antitumor effects, IFN-zeta/limitin has much less lymphomyelosuppressive activity than IFN-alpha. Unique interactions between IFN-zeta/limitin and the receptor probably led to the narrow range of signals and biological activities. A human homologue of IFN-zeta/limitin may be clinically more effective than IFN-alpha and IFN-beta because it has fewer adverse effects. Moreover, further analysis of the structure-function relationship may establish an engineered cytokine with the useful features of IFN-zeta/limitin.