Gamma interferon directly inhibits the growth of neurofibroma cells in vitro

Inhibition of the Proliferation of a Malignant Peripheral Nerve Sheath Tumor Cell Line by Gamma Interferon Gene Transfection

A solitary malignant peripheral nerve sheath tumor was resected, and a tumor cell line was obtained using an explant culture. The morphology of this cell line was quite similar to those of cell lines of dermal neurofibromas of neurofibromatosis 1, except for the fact that the malignant peripheral nerve sheath tumor cell line could be cultured for more than two months. When the tumor cell line was transfected with human gamma interferon gene, the growth rate was remarkably abolished, as previously observed in neurofibroma cell lines transfected with the gamma interferon gene. This new finding suggests the potential for treating either solitary or neurofibroma-related, inoperable, malignant peripheral nerve sheath tumors by local gamma interferon gene transfection in vivo.

Serum biomarkers for neurofibromatosis type 1 and early detection of malignant peripheral nerve-sheath tumors

BACKGROUND

Neurofibromatosis type 1 (NF1) is a hereditary tumor syndrome characterized by the development of benign nerve-sheath tumors, which transform to malignant peripheral nerve-sheath tumors (MPNST) in about 8 to 13% of patients with NF1. MPNST are invasive sarcomas with extremely poor prognosis, and their development may correlate with internal tumor load of patients with NF1. Because early identification of patients with NF1 at risk for developing MPNST should improve their clinical outcome, the aim of this study was to identify serum biomarkers for tumor progression in NF1, and to analyze their correlation with tumor type and internal tumor load.

METHODS

We selected candidate biomarkers for NF1 by manually mining published data sources, and conducted a systematic screen of 56 candidate serum biomarkers using customized antibody arrays. Serum from 104 patients with NF1 with and without MPNST, and from 41 healthy control subjects, was analyzed. Statistical analysis was performed using the non-parametric Mann-Whitney U-test, followed by Bonferroni correction.

RESULTS

Our analysis identified four markers (epidermal growth factor receptor, interferon-γ, interleukin-6, and tumor necrosis factor-α) for which significantly different serum concentrations were seen in patients with NF1 compared with healthy controls. Two markers (insulin-like growth factor binding protein 1 (IGFBP1) and regulated upon activation, normal T-cell expressed and secreted (RANTES)) showed significantly higher concentrations in patients with NF1 and MPNST compared with patients with NF1 without MPNST. A correlation with internal tumor load was found for IGFBP1.

CONCLUSION

Our study identified two serum markers with potential for early detection of patients with NF1 at risk for developing MPNST, and four markers that could distinguish between patients with NF1 and healthy subjects. Such markers may be useful as diagnostic tools to support the diagnosis of NF1 and for timely identification of MPNST. Moreover, the data suggest that there is a systemic increase in inflammatory cytokines independently of tumor load in patients with NF1.

Experimental therapeutic approaches to peripheral nerve tumors

✓Discovery that the Schwann cell is the primary cell type responsible for both the neurofibroma as well as the schwannoma has proven to represent a crucial milestone in understanding the pathogenesis of peripheral nerve tumor development. This information and related findings have served as a nidus for research aimed at more fully characterizing this family of conditions. Recent discoveries in the laboratory have clarified an understanding of the molecular mechanisms underlying the pathogenesis of benign peripheral nerve tumors. Similarly, the mechanisms whereby idiopathic and syndromic (NF1- andNF2-associated) nerve sheath tumors progress to malignancy are being elucidated. This detailed understanding of the molecular pathogenesis of peripheral nerve tumors provides the information necessary to create a new generation of therapies tailored specifically to the prevention, cessation, or reversal of pathological conditions at the fundamental level of dysfunction. The authors review the data that have helped to elucidate the molecular pathogenesis of this category of conditions, explore the current progress toward exploitation of these findings, and discuss potential therapeutic avenues for future research.

Gamma interferon gene transfection efficiently inhibits proliferation of neurofibroma cell lines in vitro

Primarily isolated neurofibroma cell lines and a human dermal fibroblast cell line were transfected with human gamma interferon gene in vitro, and changes in the cell proliferation rates were investigated. The proliferation rates of both cell lines were remarkably suppressed after the gene transfection. In particular, the neurofibroma cell lines almost stopped proliferating five days after gene transfection. The tritium thymidine uptake of the fibroblast cell line was almost abolished three days after gene transfection. The culture media from both of the gene-transfected cell lines contained a measurable gamma interferon concentration as late as five days after transfection, this was detected by an enzyme-linked immunosorbent assay. These data suggest that gamma interferon gene therapy might be a possible treatment for intractable or inoperable neurofibromas in patients with von Recklinghausen's disease in the future.