NSC 632839, also known as F6, targets the ubiquitin-proteasome system by inhibiting ubiquitin isopeptidases. NSC 632839 is able to activate an apoptosome-independent apoptotic pathway which includes a Bcl-2-dependent but apoptosome-independent mitochondrial pathway with up-regulation of the BH3-only protein Noxa, stabilization of the inhibitor of apoptosis antagonist Smac, and also the involvement of the death receptor pathway
