Inhibitory activity of nm23-H1 on invasion and colonization of human prostate carcinoma cells is not mediated by its NDP kinase activity

The human nm23-H1 gene product, a putative metastasis suppressor, was identified as nucleoside diphosphate kinase (NDPK) A isoform. To investigate the functional effect of nm23-H1’s NDPK activity on its suppression of the components of metastatic phenotype, we transfected a human prostate carcinoma cell line, DU145, with the cDNA encoding nm23-H1 mutant protein lacking NDPK activity. The mutant nm23-H1 transfected cell lines displayed decreased invasiveness and colonization in soft agar as the wild-type nm23-H1 transfectants did when compared with the control transfected line. The results suggest that the metastasis suppressing function of nm23-H1 is independent of the NDPK enzymatic activity.