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Modulation of type‐iv collagenase activity and invasive behavior of metastatic human melanoma (A2058) cells in vitro by monoclonal antibodies to type‐iv collagenase

Monoclonal antibodies (MAbs) against human type‐IV collagenase were developed and used for studies on enzyme activity and tumor‐cell invasion in vitro. Fifteen MAb clones were generated against the enzyme purified from serum‐free culture medium of human melanoma cells (A2058). Five clones affecting the activity of type‐IV collagenase were selected for further characterization. All the selected clones could be used for a single‐step purification of type‐IV collagenase using IgG‐Sepharose affinity columns. One of the antibodies activated the enzyme when 3H‐proline‐labelled type‐IV collagen was used as substrate. The activation was dependent on the enzyme antibody ratio. Four clones caused more than 30% inhibition of the activity, maximal inhibition being 50%. Interestingly, the same antibody which activated the enzyme also increased the invasion of A2058 cells through a reconstituted basement membrane in an in vitro invasion assay. The 4 inhibitory antibodies decreased the penetration of A2058 cells through the reconstituted basement membrane. The results strongly support previous findings about the importance of type‐IV collagenase in tumor‐cell invasion.