Altered collagen and glycosaminoglycan secretion by a skeletal muscle myoblast variant.

A variant of the anchorage-dependent L6 skeletal muscle myoblast cell line which grows in suspension culture was selected. This cell line, designated M3A, is aneuploid and tumorigenic, while the parental L6 line is near diploid and nontumorigenic. L6 secretes high molecular weight collagen alpha-chains, and M3A secretes a collagen-like protein of Mr = 56,000, or approximately half the size of collagen alpha-chains. Finally, both L6 and M3A synthesize hyaluronic acid, heparan sulfate, chondroitin sulfate, and chondroitin. The latter glycosaminoglycan is not, however, released into the culture medium by M3A, nor is it found in the substrate-attached material synthesized by M3A. The changes in secreted and substrate-attached material synthesized by M3A are discussed in relation to its altered growth characteristics.