Effects of sMICA on receptors of NK cells in breast cancer / 肿瘤研究与临床

ABSTRACT

Objective To observe the expression of cytotoxicity and receptors on NK cells in breast cancer,and investigate the impact of soluble MICA(sohble MHC class Ⅰ-related molecules A,sMICA) on NK cells receptors expression and cytotoxicity.Methods ELISA was used to examine the sMICA in peripheral blood.The expressions of activated receptor(NKG2D),killer inhibitory receptor (KIR)(CD158b) and NK cells were identified by flow cytometry(FCM).Cytotoxicity of NK cells to breast cancer were tested by MTT.Results sMICA was (205.36±71.27)ng/L in breast cancer patients and 81.6 % samples were detected.There were positive correlations between sMICA levels with breast cancer stages.There were no difference of NK cells percentage between breast cancer and healthy person.The cytotoxicity of NK cells and expressions of NKG2D were obviously lower in breast cancer with sMICA(+) than in healthy person,but CD158b was higher in healthy person.After cultured with sMICA,NK cells cytotoxicity decreased from(76.2±6.7)% to(48.4±4.1)% and the expression of NKG2D reduced from(92.5±7.1)% to (62.5±6.4)%,but the the expression of CD158b increased from(10.6±3.2)% to (43.6±3.4)%.IL-15 up regulated the expression of NKG2D and NK cells cytotoxicity,but decreased the expression of CD158b by co-culturation with IL-15 and sMICA in sMICA+ patients with breast cancer.Conclusion sMICA reduced the expression of NKG2D and increased the expression of Kill,which lead to the down regulation of NK cells cytotoxicity.IL-15 can reverse this effect.