EFFECTS OF MECHANICAL TRAUMA AND FREE-RADICAL EXPOSURE ON THE MEMBRANE-INTEGRITY OF EHRLICH ASCITES TUMOR-CELLS

During hematogenous metastasis, the majority of cancer cells entering the microcirculation are rapidly killed as a consequence of loss of me mbrane integrity. This is partially due to mechanical trauma associate d with intramicrovascular cancer cell deformation, and possibly to the action of free radicals released by endothelial and other cells. In a n in vitro analysis of these two modalities, we have studied the effec ts of mechanical (filtration) trauma and exposure to hydrogen peroxide on the surface membrane integrity of Ehrlich ascites tumor cells. It was shown that final concentrations of H2O2 down to 0.001%, and filtra tion through 10 mum Nuclepore(R) each produced significant loss in sur face membrane integrity. An additive effect was demonstrated between e xposure to 0.001% H2O2 and filtration, but the additive effect was not detectable at 0.01%. Overall, the results indicate the feasibilty of trauma due to mechanical deformation and exposure to free radicals, co ntributing to the inefficiency of the metastatic process.