The small molecule NSC676914A is cytotoxic and differentially affects NFκB signaling in ovarian cancer cells and HEK293 cells

BACKGROUND: The small molecule NSC676914A was previously identified as an NF-κB inhibitor in TPA-stimulated HEK293 cells (Mol Can Ther 8:571-581, 2009). We hypothesized that this effect would also be seen in ovarian cancer cells, and serve as its mechanism of cytotoxicity. OVCAR3 and HEK293 cell lines stably containing a NF-κB luciferase reporter gene were generated. METHODS: Levels of NF-κB activity were assessed by luciferase reporter assays, after stimulation with LPA, LPS, TPA, and TNFα, in the presence or absence of a known NF-κB inhibitor or NSC676914A, and cytotoxicity was measured. RESULTS: NSC676914A was toxic to both OVCAR3 and HEK293 cells. We also investigated the cytotoxicity of NSC676914A on a panel of lymphoma cell lines with well characterized mutations previously shown to determine sensitivity or resistance to NF-κB inhibition. The compound did not show predicted patterns of effects on NF-κB activity in either lymphoma, ovarian or HEK293 cell lines. In HEK293 cells, the small molecule inhibited NF-κB when cells were stimulated, while in OVCAR3 cells it only partially inhibited NF-κB. Interestingly, we observed rescue of cell death with ROS inhibition. CONCLUSIONS: The current study suggests that the effect of NSC676914A on NF-κB depends on cell type and the manner in which the pathway is stimulated. Furthermore, as it is similarly toxic to lymphoma, OVCAR3 and HEK293 cells, NSC676914A shows promising NF-κB-independent anti-cancer activity in ovarian tumor cells.