Effect of antifreeze proteins on frozen primary prostatic adenocarcinoma cells

Abstract

Objectives Recent studies show that prostate adenocarcinoma cells can survive cryosurgery and that cell destruction depends on the specific thermal parameters used during freezing. The goal of this preliminary study is to determine whether certain chemical compounds, known as antifreeze proteins, can induce complete human primary prostatic adenocarcinoma cell destruction by freezing, regardless of the thermal parameters used. The study also examines the mechanism by which antifreeze proteins bring about cell destruction. Methods Antifreeze proteins were added to solutions containing human primary prostatic adenocarcinoma cells. The cells were frozen with controlled thermal parameters using a directional solidification apparatus attached to a light microscope. Cell viability was determined after thawing as a function of antifreeze protein concentration and cooling rate during freezing. Results The dose response study shows that for all the cooling rates tested, 10-mg/mL solutions of antifreeze protein cause the complete destruction of human primary prostatic adenocarcinoma cells frozen to a temperature at which, without these proteins, the cells survive freezing. Light microscopy shows that the lethal effect of the antifreeze proteins is related to the formation of intracellular ice in the frozen cells. Conclusions This preliminary study has demonstrated that antifreeze proteins have the ability to generate complete destruction of prostatic adenocarcinoma cells frozen to high subzero temperatures irrespective of the cooling rates used during freezing. This suggests that introducing antifreeze proteins into undesirable tissues prior to freezing may increase the efficacy and the control over tissue destruction by cryosurgery.