Enhancement of lung-colonizing ability of cloned low-metastatic lewis lung carcinoma cells by treatment with highly polar compounds

Abstract

Treatment of low‐metastatic Lewis lung carcinoma cells (P‐29) with dimethylsulfoxide (DMSO) in vitro enhanced their lung‐colonizing ability. The effects of other highly polar compounds on the lung‐colonizing ability of P‐29 cells were examined. The following compounds were found to enhance the lung‐colonizing ability of the cells: acetamide, N‐methylacetamide, N‐methylformamide, N,N‐dimethylformamide, piperidone and hexamethylphosphoric triamide. Treatment of P‐29 cells with DMSO or other polar compounds resulted in increases in activities of degradative enzymes, such as cathepsin B and plasminogen activator. The increases in cathepsin B and plasminogen activator activities were apparent after a 24 h treatment with DMSO and were suppressed by simultaneous treatment with cycloheximide, which suggested that they were due to syntheses of new proteins. DMSO‐treated P‐29 cells degraded [³H]leucine‐labelled subendothelial matrix much more than did untreated cells. P‐29 cells treated with DMSO or other polar compounds became attached to culture dishes more rapidly and were more resistant to detachment by trypsin treatment than untreated cells. A significant correlation was found between the degrees of adhesiveness of P‐29 cells treated with various polar compounds and their lung‐colonizing abilities.