p53, a tumor suppressor gene involved in the G1 cell cycle checkpoint, is also the most frequently mutated gene in human
cancer. In addition, p53 modifies the ability of
tumor cells to metastasize. The
metastasis-associated gene Nm23-H1, which encodes an 18-kDa
nucleoside diphosphate kinase, was previously identified in cells with low metastatic potential. Although p53 and Nm23-H1
proteins play an important part in regulating the progression of
cancer, any functional relationship between these two
proteins is currently unknown. Here we report an association between p53 levels and expression of the Nm23-H1 gene. Our data indicate that wild-type (wt) p53 upregulated the expression of Nm23-H1 at
protein and
mRNA levels in MCF-7 and J7B cells. This capacity of wt p53 to regulate expression of Nm23-H1 was not only dependent on the endogenous but also the exogenous origin of p53, and could not be reproduced with mutant p53. Subsequently, the invasive ability of MCF-7 and J7B cells was suppressed upon induction of the Nm23-H1
protein by p53. In contrast, increased levels of p53 downregulated the expression of Nm23-H1 at the
protein and
mRNA levels in RKO and H1299 cells and, as a consequence, increased the invasive ability of both cell types. Thus, our results implicated the differential regulation of Nm23-H1 by p53 in different cell types as an important component in the molecular mechanisms of
tumor metastasis.