Protein cross-linking as a novel mechanism of action of a ubiquitin-activating enzyme inhibitor with anti-tumor activity

• Published in: Biochemical pharmacology Vol. 82; no. 4; pp. 341 - 349
• Main Authors: Kapuria, Vaibhav, Peterson, Luke F., Showalter, H.D. Hollis, Kirchhoff, Paul D., Talpaz, Moshe, Donato, Nicholas J.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 15.08.2011; Elsevier
• Subjects: Abl protein; animals; anticarcinogenic activity; Antineoplastic Agents - chemistry; Antineoplastic Agents - metabolism; Antineoplastic Agents - pharmacology; Antitumor agents; BCR protein; Benzoates - chemistry; Benzoates - metabolism; Benzoates - pharmacology; Biological and medical sciences; Cancer; Cross-linking; Cross-Linking Reagents - chemistry; Cross-Linking Reagents - metabolism; Cross-Linking Reagents - pharmacology; crosslinking; Deubiquitinase; Enzymatic activity; enzyme activity; Enzyme Inhibitors - chemistry; Enzyme Inhibitors - metabolism; Enzyme Inhibitors - pharmacology; Furans - chemistry; Furans - metabolism; Furans - pharmacology; Fusion protein; HEK293 Cells; Humans; Inhibitor; Janus kinase 2; K562 Cells; mechanism of action; Medical sciences; Pharmacology. Drug treatments; Protein kinase; protein kinases; Pyrazoles - chemistry; Pyrazoles - metabolism; Pyrazoles - pharmacology; Signal transduction; therapeutics; Tumor cells; Ubiquitin; Ubiquitin-activating enzyme; Ubiquitin-Activating Enzymes - antagonists & inhibitors; Ubiquitin-Activating Enzymes - metabolism; ubiquitin-protein ligase; Ubiquitinated Proteins - chemistry; Ubiquitinated Proteins - metabolism; ubiquitination; Ubiquitin-activating enzyme; Inhibitor; Deubiquitinase; Cross-linking; Antineoplastic agent; Carbon-nitrogen ligases; Enzyme; Crosslinking; Biological activity; Protein; Ligases; Mechanism of action; Ubiquitin-protein ligase
• ISSN: 0006-2952; 1873-2968
• DOI: 10.1016/j.bcp.2011.05.012

Ubiquitin-activating enzyme 1 (UBE1) is a critical regulator of the ubiquitination cycle and its targeted inhibition may be an appropriate therapeutic strategy as tumor cells are reported to have increased dependence on protein ubiquitination. PYR-41 is a small molecule with previously described UBE1 inhibitory activity. PYR-41 blocks ubiquitination reactions but paradoxically leads to the accumulation of high MW ubiquitinated proteins. Detailed evaluation of PYR-41 activity demonstrated that PYR-41 inhibited UBE1 activity but also had equal or greater inhibitory activity against several deubiquitinases (DUBs) in intact cells and purified USP5 in vitro. Both UBE1 and DUB inhibition were mediated through PYR-41-induced covalent protein cross-linking which paralleled the inhibition of the target proteins enzymatic activity. PYR-41 also mediated cross-linking of specific protein kinases (Bcr-Abl, Jak2) to inhibit their signaling activity. Chemical reactivity modeling provided some insight into the cross-linking potential and partial target selectivity of PYR-41. Overall, our results suggest a broader range of targets and a novel mechanism of action for this UBE1 inhibitor. In addition, since PYR-41-related compounds have demonstrated anti-tumor activity in animal studies, partially selective protein cross-linking may represent an alternate approach to affect signal transduction modules and ubiquitin cycle-regulatory proteins for cancer therapy.