Sulforaphane induces ROS mediated induction of NKG2D ligands in human cancer cell lines and enhances susceptibility to NK cell mediated lysis

Aims: The goal of this study is to investigate the tumor cytotoxic effects of sulforaphane (SFN) and ionizing radiation (IR) as well as their ability to up-regulate natural killer group 2, member D (NKG2D) ligands and modulate the susceptibility of tumor cells to natural killer (NK) cell-mediated killing. Main methods: Expression of MHC class I-related chain molecules A and B (MICA/MICB) and total reactive oxygen species (ROS) were assessed by flow cytometry following labeling with appropriate dyes or antibodies. NK cell cytotoxicity was determined by calcein release of target cells. Key findings: The expression of NKG2D ligands MICA/MICB was found to vary in all the four tumor cell lines tested (MCF7