Primary Cultures of Human Vestibular Schwannoma

Abstract

To establish primary vestibular schwannoma (VS) cultures that selectively favor the growth of schwannoma cells. The lack of a suitable in vitro model of human VS cells has directly limited the progress of research on tumorigenesis and therapy. The problems of establishing pure VS culture include control of fibroblast proliferation. Current efforts to extend VS cell life span using viral oncogenes, by conferring the ability to proliferate in vitro, will yield cells intrinsically different from in vivo VS tumors. Much more desirable is the ability to culture VS cells without cellular transformation. Tumor specimens from 17 patients were processed for cell culture and grown at 37 degrees C with 5% CO2 and 100% humidity. Key modifications limiting fibroblast proliferation included using selective medium without L-valine, supplemented by Nu-Serum for at least a week; the use of cytosine arabinoside to kill contaminating fibroblasts; and using the Dulbecco modified medium, supplemented with brain-derived neurotrophic factor and 10% fetal calf serum after the initial serum-free period. Twelve of 17 VS were successfully cultured. The presence of schwannoma cells and the absence of fibroblasts were confirmed immunohistochemically using S100 and CD90 markers, respectively. Scanning and transmission electron microscopy demonstrated typical spindle-shaped cells and the presence of "fibrous long-spacing collagen." We describe a method for obtaining short-term, essentially fibroblast-free, primary VS cultures. Such pure VS cultures, retaining in vivo characteristics, are extremely useful as an in vitro model to study the pathobiology of schwannoma cells.