VEGF targeting in mesotheliomas using an interleukin-6 signal inhibitor based on adenovirus gene delivery.

BACKGROUND: Malignant mesotheliomas reportedly secrete interleukin-6 (IL-6) which augments production of vascular endothelial growth factor (VEGF) from mesothelioma cells. We previously reported the development of a new receptor inhibitor of IL-6 (NRI) by genetically engineering tocilizumab, a humanized anti-IL-6 receptor monoclonal antibody. Since NRI is encoded on a single gene, it is easily applicable to a gene delivery system using virus vehicles. In this study, we report VEGF targeting through NRI expression based on adenovirus-mediated gene delivery in mesothelioma cells. MATERIALS AND METHODS: We constructed an NRI expression vector in the context of a tropism-modified adenovirus vector that had enhanced infectivity in mesothelioma cells. RESULTS: This virus effectively induced NRI secretion from mesothelioma cells. This virus infection also reduced the VEGF production in mesothelioma cells. CONCLUSION: These results indicate that NRI shows potential as an agent in the treatment of mesotheliomas.

Interactions among type I and type II interferon, tumor necrosis factor, and beta-estradiol in the regulation of immune response-related gene expressions in systemic lupus erythematosus.

INTRODUCTION: Systemic lupus erythematosus (SLE) is a prototypical autoimmune disease characterized by various clinical manifestations. Several cytokines interact and play pathological roles in SLE, although the etiopathology is still obscure. In the present study we investigated the network of immune response-related molecules expressed in the peripheral blood of SLE patients, and the effects of cytokine interactions on the regulation of these molecules. METHODS: Gene expression profiles of peripheral blood from SLE patients and from healthy women were analyzed using DNA microarray analysis. Differentially expressed genes classified into the immune response category were selected and analyzed using bioinformatics tools. Since interactions among TNF, IFNgamma, beta-estradiol (E2), and IFNalpha may regulate the expression of interferon-inducible (IFI) genes, stimulating and co-stimulating experiments were carried out on peripheral blood mononuclear cells followed by analysis using quantitative RT-PCR. RESULTS: Thirty-eight downregulated genes and 68 upregulated genes were identified in the functional category of immune response. Overexpressed IFI genes were confirmed in SLE patient peripheral bloods. Using network-based analysis on these genes, several networks including cytokines--such as TNF and IFNgamma--and E2 were constructed. TNF-regulated genes were dominant in these networks, but in vitro TNF stimulation on peripheral blood mononuclear cells showed no differences in the above gene expressions between SLE and healthy individuals. Co-stimulating with IFNalpha and one of TNF, IFNgamma, or E2 revealed that TNF has repressive effects while IFNgamma essentially has synergistic effects on IFI gene expressions in vitro. E2 showed variable effects on IFI gene expressions among three individuals. CONCLUSIONS: TNF may repress the abnormal regulation by IFNalpha in SLE while IFNgamma may have a synergistic effect. Interactions between IFNalpha and one of TNF, IFNgamma, or E2 appear to be involved in the pathogenesis of SLE.

A case report of a patient with refractory adult-onset Still's disease who was successfully treated with tocilizumab over 6 years.

Interleukin-6 overproduction is pathologically involved in adult onset Still's disease (AOSD). We successfully treated a man with refractory AOSD utilizing tocilizumab. Tocilizumab was discontinued after 15 doses due to intestinal bleeding, but the efficacy was sustained over 21 months. Tocilizumab was readministered safely upon recurrence and showed similar efficacy over 6 years. Corticosteroid and NSAIDs could be discontinued and intestinal bleeding was no more observed. Tocilizumab can be a therapeutic option for AOSD.

Gene therapy for multiple myeloma.

Prognosis of multiple myeloma (MM) remains insufficient despite the intervention of high dose chemotherapy with auto- or allo- hematopoietic stem cell transplantation and the advent of molecular target drugs such as thalidomide, lenalidomide, and bortezomib. Further development or new concepts of therapeutic approaches are still required for MM treatment. Current standard protocol for MM treatment does not include gene delivery method or oncolytic virus approaches. Since MM is a disorder originated from B cell lineage, it involves immunological aspects in both pathogenesis and clinical manifestations. Therefore, the comprehension of immunology as well as oncology is essential to exploit new therapeutic approaches. Recently, novel therapeutic concepts for MM have been emerging. In this review, we present current progress of gene therapy related to MM treatments as well as the overview of MM treatment history.

The blockade of IL-6 signaling in rational drug design.

After three decades from the development of the hybridoma technology, a monoclonal antibody-based therapy targeting the inflammatory cytokine has been established as an ultimate treatment for chronic inflammatory diseases. Interleukine-6 (IL-6) is one of the inflammatory cytokines playing a pivotal role in these conditions, and strategies targeting IL-6 signal show promise in the treatment of chronic inflammatory diseases such as rheumatoid arthritis, juvenile idiopathic arthritis, and Crohn's disease. Although many groups have been exploring the approach to block the IL-6 signal, tocilizumab, a humanized monoclonal antibody of the IL-6 receptor, has been the most intensively studied agent for clinical use. Clinical trials regarding chronic inflammatory diseases described above have demonstrated efficacy of tocilizumab, however, this treatment has limitations in terms of economic costs and ease of administration, and further advances are necessary to expand the concept of IL-6-specific therapeutics. In this review, we discuss targeting IL-6 in a rational drug design and present the various strategies to achieve this.

Successful treatment of a patient with Takayasu arteritis using a humanized anti-interleukin-6 receptor antibody.

Takayasu arteritis (TA) is a chronic inflammatory disease that involves the aorta and its major branches. Since overproduction of interleukin-6 (IL-6) seems to play a pathogenic role in TA, we used the anti-IL-6 receptor (IL-6R) antibody tocilizumab to treat a 20-year-old woman with refractory active TA complicated by ulcerative colitis (UC). Treatment with tocilizumab improved the clinical manifestations of TA and the abnormal laboratory findings in this patient and ameliorated the activity of UC. These results indicate that IL-6R inhibition with tocilizumab might be a future treatment option for TA.

Establishment of a new interleukin-6 (IL-6) receptor inhibitor applicable to the gene therapy for IL-6-dependent tumor.

Interleukin-6 (IL-6) is a key molecule involved in the pathogenesis of several inflammatory diseases and malignancies. Treatments that inhibit IL-6 mitigate the clinical conditions of such diseases. Here, we report on the development of a new receptor inhibitor of IL-6 (NRI) by genetically engineering tocilizumab, a humanized anti-IL-6 receptor monoclonal antibody which specifically blocks IL-6 signaling. This NRI consists of VH and VL of tocilizumab in a single-chain fragment format dimerized by fusing to the Fc portion of human immunoglobulin G(1). The binding activity to IL-6 receptor and the biological activity of the purified NRI were found to be similar to those of parental tocilizumab. Because NRI is encoded on a single gene, it is easily applicable to a gene delivery system using virus vehicles. We administered an adenovirus vector encoding NRI to mouse i.p. and monitored the serum NRI level and growth reduction property on S6B45, an IL-6-dependent multiple myeloma cell line, in vivo. Adequate amount of the serum NRI level to exert anti-IL-6 action could be obtained by the NRI gene introduction combined with adenovirus gene delivery, and this treatment inhibited the in vivo S6B45 cell growth significantly. These findings indicate that NRI is a promising agent applicable to the therapeutic gene delivery approach for IL-6-driven diseases.

Interleukin-6 induces both cell growth and VEGF production in malignant mesotheliomas.

Malignant mesothelioma (MM), an incurable tumor, is reportedly an interleukin-6 (IL-6) secreting tumor. The pathological significance of IL-6 overexpression in this tumor, however, has remained unclear. We investigated the biological functions of IL-6 in mesotheliomas. Five mesothelioma cell lines were analyzed for IL-6 production and IL-6 receptor (IL-6R) expression. Of them, 2 produced high levels of IL-6, 2 produced intermediate levels and 1 cell line showed no secretion. All mesothelioma cell lines used in this study expressed very small amounts of IL-6R mRNA. We compensated for this low level of IL-6R expression in mesotheliomas by adding recombinant soluble IL-6R (sIL-6R) to mediate the IL-6 signal. IL-6 together with sIL-6R was found to promote cell growth of H2052 and H226 MMs classified as high-level IL-6 producers in a dose-dependent manner. Moreover, a humanized anti-IL-6R antibody (MRA) capable of blocking IL-6 signaling suppressed the cell growth of mesotheliomas induced by IL-6/sIL-6R. These findings demonstrate that IL-6 serves as an autocrine growth factor in the development of mesothelioma. In addition, IL-6/sIL-6R stimulation increased the expression of vascular endothelial growth factor (VEGF) in 4 out of 5 cell lines, and this induction was inhibited by MRA treatment. The involvement of the signal transducer and activator of transcription 3 (STAT3) pathway in both cell growth and VEGF induction by IL-6/sIL-6R was verified by dominant negative STAT3 transduction combined with adenovirus gene-delivery methods. Although IL-6 induces VEGF through the JAK2/STAT3 pathway, anti-VEGF antibody could not inhibit the IL-6-induced cell growth observed in H2052 and H226. We concluded that IL-6-dependent growth does not occur via VEGF induction. These results suggest that treatment with anti-IL-6R antibody may constitute a potential molecular targeting therapy for MMs.