phenylmercuric-acetate and Carcinoma-256--Walker

Walker 256 (W256) cancer cells, developed as ascites in rats, in response to endogenous unidentified stimuli, secrete a gelatinase of apparent molecular mass of 94 kDa, immunologically homologous to the zymogen of matrix metalloproteinase-9 (proMMP-9). After treatment with the activating agent 4-aminophenylmercuric acetate (APMA), affinity-purified W256 gelatinase is converted to a final processed form of 66 kDa in a similar fashion to TIMP-free human proMMP-9. It is demonstrated that although being capable of binding TIMP-1, W256 proMMP-9 is secreted from W256 cells in TIMP-free forms (monomers or oligomers). Moreover, using biochemical and immunological methods, it is established that the W256 cells do not express or secrete TIMP-1 protein, although RT-PCR analysis indicated low-level TIMP-1 mRNA expression. W256 cancer cells displayed high metastatic ability in rats that may be attributed in part to secretion of TIMP-free proMMP-9.

Topics: Animals; Carcinoma 256, Walker; Cell Line, Tumor; Gelatinases; Humans; Matrix Metalloproteinase 9; Neoplasm Metastasis; Phenylmercuric Acetate; Rats; RNA, Messenger; Tissue Inhibitor of Metalloproteinase-1