Nm23-H1 gene as a molecular switch between the free-floating and adherent states of gastric cancer cells

The contribution of the nm23-H1 gene to metastasis in malignant tumors, inc luding gastric cancer, is controversial. In this study, we compared nm23-H1 levels in two cell subtypes with different morphologies (floating and adhe rent states), but that were derived from the same gastric cancer cell line, KATO-III. A real-time quantitative reverse transcription-polymerase chain reaction showed that the number of nm23-H1 mRNA molecules in floating cells was significantly higher than that in adherent cells (P < 0.0001). The ave rage of the copies in floating cells was approximately 2.4-fold higher than that in adherent cells. Consistent with mRNA levels, intracellular levels of nm23-H1 protein were higher in floating cells than in adherent cells. Th ere was no difference in cell cycle characteristics between the two subtype s. In conclusion, our present data indicate that expression of nm23-H1 by a tumor could be altered during the different steps in metastases, suggestin g that nm23-H1 may act as a molecular switch between the free-floating and adherent states of cancer cells. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.