Comparison of human tenascin expression in normal, Simian‐virus‐40‐transformed and tumor‐derived cell lines

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Abstract
Tenascin is a polymorphic high‐molecular‐mass extracellular‐matrix glycoprotein composed of six similar subunits. Using two‐domain‐specific anti‐tenascin monoclonal antibodies, we have studied the expression and distribution of tenascin in four cultured normal human fibroblasts, two simianvirus‐40‐(SV40)‐transformed and three tumor‐derived (melanoma, rhabdomyosarcoma and fibrosarcoma) cell lines. We found that (a) cultured normal human fibroblasts accumulate considerable amounts of tenascin and retain 60–90% in the extracellular matrix, while they release the remainder into the tissue‐culture medium; (b) of the two SV40‐transformed counterparts we have tested, the AG‐280 cell line accumulates no detectable amounts of tenascin and the WI‐38‐VA cell line accumulates about 10‐times less tenascin than its normal counterpart and releases about 90% of it into the culture medium; (c) some tumor‐derived cell lines accumulate considerable amounts of tenascin, but in theses cases, more than 90% is released into the culture media; (d) in normal human fibroblasts, two major tenascin isoforms, generated by alternative splicing of the mRNA precursor, are detectable (280 kDa and 190 kDa, respectively) and the lower‐molecular‐mass tenascin isoform is accumulated preferentially in the extracellular matrix; (e) in SV40‐transformed or tumor‐derived cell lines, only the higher‐molecular‐mass isoform is detectable and it is more sialylated than the tenascin produced by the normal human fibroblast cell lines.

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