Cell experiment:

Different drug concentrations are used to determine the dose-response profile and to calculate the IC50 value. Cells are incubated with the required concentrations of the 57 compounds. After 24 or 48 hours of incubation, cell death is evaluated bytr ypan blue staining[1].

IC50: ~30 μM

Ubiquitin Isopeptidase Inhibitor I is a ubiquitin isopeptidase inhibitor.

Conjugation or deconjugation of ubiquitin or ubiquitin-like proteins to or from cellular proteins is a multifaceted and universal ways of regulating cellular physiology, controlling the lifetime, localization, and activity of various key proteins.

In vitro: Ubiquitin Isopeptidase Inhibitor I targeted the ubiquitinproteasome system via inhibiting the ubiquitin isopeptidases. Ubiquitin Isopeptidase Inhibitor I could induce a rather unique apoptotic pathway, including a Bcl-2-dependent but apoptosome-independent mitochondrial pathway with upregulation of the BH3-only protein Noxa, stabilization of the inhibitor of apoptosis antagonist Smac, but also the involvement of the death receptor pathway. Moreover, the treatment of Ubiquitin Isopeptidase Inhibitor I to cell extracts obtained from E1A cells did not inhibit the proteolytic activity of the proteasome, whereas MG-132 potently inhibited the cleavage of the LLVY-AMC substrate. In addition, Noxa induction by Ubiquitin Isopeptidase Inhibitor I could be inhibited by the specific RNAi oligos efficiently. When apoptosis was scored, it was found that down-regulation of Noxa was able to inhibit but did not suppress apoptosis and caspase activation in response to Ubiquitin Isopeptidase Inhibitor I treatment [1].

In vivo: So far, there is no animal in vivo data reported.

Clinical trial: Up to now, Ubiquitin Isopeptidase Inhibitor I is still in the preclinical development stage.

Reference:
[1] E.  Aleo, C. J. Henderson, A. Fontanini, et al. Identification of new compounds that trigger apoptosome-independent caspase activation and apoptosis. Cancer Research 66(18), 9235-9244 (2006).