Increased cell hydration promotes both tumor growth and metastasis: A biochemical mechanism consistent with genetic signatures

Abstract

It was postulated previously that a progressive increase in cell hydration, induced by successive genetic or epigenetic changes, is the basic mechanism of multistep carcinogenesis, and also that the degree of malignancy increases with the degree of cell hydration. These hypotheses implied that increased cell hydration is a common factor promoting both tumor growth and metastasis, and that metastatic potential increases with the degree of cell hydration. This paper discusses these implications in relation to current concepts of genetic mechanisms determining the acquisition of metastatic potential. It was also postulated previously that the enhancement of metabolic activity by increased cell hydration will increase the ability of tumor cells to compete for nutrients with their normal counterparts. This effect may favor the preferential selection of cells whose genotypes confer the greatest increase in cell hydration and which, on the present hypothesis, would be those with the greatest capacity for metastasis. An important feature of this "common factor" hypothesis is that it suggests a biochemical explanation for DNA-microarray data showing a similarity between the gene expression patterns associated with both tumor growth and metastasis, while the postulated role of genes causing increased cell hydration might explain the apparent acquisition of metastatic potential at an early stage of tumorigenesis. Previous investigations were consistent with the hypothesis that various factors promoting carcinogenesis may do so by increasing cell hydration. A survey of the literature showed that all of these factors also promote cell motility, migration or metastasis, and provided evidence that these effects could be attributed to the associated increase in cell hydration. Methods are suggested for testing the hypothesis, and the paper concludes by emphasizing the need for more research on the biochemistry of cancer, and on the role of water as a biochemical factor of particular importance, not only in carcinogenesis, but in many other aspects of cell biology.