Production of SPARC/osteonectin/BM-40 was determined in mouse B16 melanoma clones BL6 and F10 (high metastatic) and F1 (low metastatic). SPARC was produced greater amount in BL6 and F10 than in F1 cells, showing a good agreement with their metastatic potentials. Moreover, SPARC production was not influenced by culture pH, even in the acidic conditions (≈pH 5.9). Although tumor tissues show often low pH due to excessive amount of acidic metabolites such as lactate, most studies have been done in

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... neutral pH. High SPARC production in the acidic medium, therefore, is thought to be an important potential for tumor invasive behaviour. 18. Kato Y, Nakayama Y,Umeda M, Miyazaki K: Induction of 103-kDa gelatinase/type IV collagenase by acidic culture conditions in mouse metastatic melanoma cell lines, J Biol Chem 267: 11424-11430,1992. 19. Kato Y, Ozono S, Shuin T, Miyazaki K: Slow induction of gelatinase B mRNA by acidic culture conditions in mouse metastatic melanoma cells.