Abstract 521: 4, 4′-Dichlorodiphenyltrichloroethane (DDT) and Triclosan (TCS) decrease tumor-cell-binding capacity and cell-surface protein expression of human natural killer cells

Abstract

4, 4′-Dichlorodiphenyltrichloroethane (DDT) and Triclosan (TCS) are organochlorine compounds that contaminate the environment, are found in human blood, and have been shown to decrease the tumor-cell killing (lytic) function of human natural killer (NK) cells. NK cells defend against tumor cells and virally infected cells. This study examined concentrations of DDT and PCP that decrease lytic function for alteration of NK binding to tumor targets. Levels of either compound that caused loss of binding function were then examined for effects on expression of cell-surface proteins needed for binding. CD16 is an Fc receptor and CD56 is a cognate of neural cell adhesion molecules, both of which are present on NK cells and involved in recognition and lysis of NK target. NK cells exposed to 2.5 µM DDT for 24 h (which caused a greater than 55% loss of lytic function) showed a decrease in NK binding function of about 23%, and a decrease in CD16 of 20%. NK cells exposed to 5 µM TCS for 24 h showed a decrease in ability to bind tumor cells of 44% and a decrease in expression of CD56 of about 34%. This same treatment caused a decrease in lytic function of greater than 87%These results indicated that only a portion of the loss of NK lytic function seen with exposures to these compounds could be accounted for by loss of binding function and also accompanied by loss of cell-surface protein expression. Supported by NIH grant 1U54CA163066-01 and S06 GM008092-35 Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 521. doi:1538-7445.AM2012-521