Background:

IC50: N/A

NSC 687852 is a 19S regulatory particle inhibitor.

The 19S particles bind polyubiquitin-linked polypeptides and present them to the 20S degradative units. USP14 and UCHL5 are cysteine enzymes that become activated after being associated with the proteasome.

In vitro: NSC 687852 blocked deubiquitylating activity of USP14 and UCHL5 selectively without inhibiting proteasome activity. NSC 687852 decreased viability in multiple myeloma (MM) cell lines and patient MM cells, inhibited MM cell proliferation even in the presence of bone marrow stroma cells, and overcomed bortezomib resistance. Anti-MM activity of NSC 687852 was associated with growth arrest through downregulating CDC2, CDC25C, and cyclin B1, as well as induction of caspase-dependent apoptosis and activation of unfolded protein response [1].

In vivo: In vivo studies using distinct human MM xenograft models showed that NSC 687852 was well tolerated, inhibited tumor growth, and prolonged mouse survival. Combination of NSC 687852 with suberoylanilide hydroxamic acid, lenalidomide, or dexamethasone was found to induce synergistic anti-MM activity [1].

Clinical trial: N/A

Reference:
[1] Ze Tian,Padraig D'Arcy,Xin Wang,Arghya Ray,Yu-Tzu Tai,Yiguo Hu,Ruben D Carrasco,Paul Richardson,Stig Linder,Dharminder Chauhan,Kenneth C Anderson.  A novel small molecule inhibitor of deubiquitylating enzyme USP14 and UCHL5 induces apoptosis in multiple myeloma and overcomes bortezomib resistance. Blood. 2014 Jan 30; 123(5): 706–716.