NFKB1 and neoplasm: Regarding cytotoxicity, the anti-tumor potential of PAs in the 3D co-culture spheroids was predictable based on the SAR studies for NFκB inhibition with (1) and (1s) showing striking reduction of cell viability at an IC50 of 21.7 ± 2.5 nM and 11.2 ± 2.1 nM, respectively.