Effects of zinc on tumor transplantability

The effects of zinc treatment on the transplantability of tumor cells were investigated in two syngeneic murine tumor systems. A 15-min incubation of tumor cells in 0.1 mM zinc caused a dramatic decrease in intravenous transplantability for melanoma B16 cells, while MCG 101-AA cells were unaffected. The subcutaneous transplantability remained unchanged in both cases. In order to elucidate the mechanism responsible for the effect on B16 cells, a number of factors of possible importance for the intravenous transplantability were investigated. Zinc treatment reduced the activity of extracellular neutral protease, and increased the cell rigidity and fragility in a similar way in both cell lines. However, zinc effects on cell adhesion and cell proliferation were different in the two cell lines. It is possible that zinc reduces the intravenous transplantability of melanoma B16 cells by impairment of cell adhesion.