title: Discovery of inhibitors that elucidate the role of UCH-L1 activity in the H1299 lung cancer cell line.
abstract: Neuronal ubiquitin C-terminal hydrolase (UCH-L1) has been linked to Parkinson's disease (PD), the progression of certain nonneuronal tumors, and neuropathic pain. Certain lung tumor-derived cell lines express UCH-L1 but it is not expressed in normal lung tissue, suggesting that this enzyme plays a role in tumor progression, either as a trigger or as a response. Small-molecule inhibitors of UCH-L1 would be helpful in distinguishing between these scenarios. By utilizing high-throughput screening (HTS) to find inhibitors and traditional medicinal chemistry to optimize their affinity and specificity, we have identified a class of isatin O-acyl oximes that selectively inhibit UCH-L1 as compared to its systemic isoform, UCH-L3. Three representatives of this class (30, 50, 51) have IC(50) values of 0.80-0.94 micro M for UCH-L1 and 17-25 micro M for UCH-L3. The K(i) of 30 toward UCH-L1 is 0.40 micro M and inhibition is reversible, competitive, and active site directed. Two isatin oxime inhibitors increased proliferation of the H1299 lung tumor cell line but had no effect on a lung tumor line that does not express UCH-L1. Inhibition of UCH-L1 expression in the H1299 cell line using RNAi had a similar proproliferative effect, suggesting that the UCH-L1 enzymatic activity is antiproliferative and that UCH-L1 expression may be a response to tumor growth. The molecular mechanism of this response remains to be determined.
authors.affiliation: Center for Neurologic Diseases, Brigham and Women's Hospital, 65 Landsdowne Street, Cambridge, MA 02139, USA.
authors.forename: Yichin
authors.initials: Y
authors.lastname: Liu
authors.forename: Hilal A
authors.initials: HA
authors.lastname: Lashuel
authors.forename: Sungwoon
authors.initials: S
authors.lastname: Choi
authors.forename: Xuechao
authors.initials: X
authors.lastname: Xing
authors.forename: April
authors.initials: A
authors.lastname: Case
authors.forename: Jake
authors.initials: J
authors.lastname: Ni
authors.forename: Li-An
authors.initials: LA
authors.lastname: Yeh
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Cuny
authors.forename: Ross L
authors.initials: RL
authors.lastname: Stein
authors.forename: Peter T
authors.initials: PT
authors.lastname: Lansbury
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D004353:Drug Evaluation, Preclinical / Q000379:methods; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D020128:Inhibitory Concentration 50; D007510:Isatin / Q000737:chemistry / Q000494:pharmacology*; D007527:Isoenzymes / Q000037:antagonists & inhibitors; D008175:Lung Neoplasms / Q000473:pathology*; D010091:Oximes / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D043222:Ubiquitin Thiolesterase / Q000037:antagonists & inhibitors*
chemical_list: D000970:Antineoplastic Agents; D004791:Enzyme Inhibitors; D007527:Isoenzymes; D010091:Oximes; D007510:Isatin; D043222:Ubiquitin Thiolesterase