Dataset Information

A Potent and Selective Quinoxalinone-Based STK33 Inhibitor Does Not Show Synthetic Lethality in KRAS-Dependent Cells.

ABSTRACT: The KRAS oncogene is found in up to 30% of all human tumors. In 2009, RNAi experiments revealed that lowering mRNA levels of a transcript encoding the serine/threonine kinase STK33 was selectively toxic to KRAS-dependent cancer cell lines, suggesting that small-molecule inhibitors of STK33 might selectively target KRAS-dependent cancers. To test this hypothesis, we initiated a high-throughput screen using compounds in the Molecular Libraries Small Molecule Repository (MLSMR). Several hits were identified, and one of these, a quinoxalinone derivative, was optimized. Extensive SAR studies were performed and led to the chemical probe ML281 that showed low nanomolar inhibition of purified recombinant STK33 and a distinct selectivity profile as compared to other STK33 inhibitors that were reported in the course of these studies. Even at the highest concentration tested (10 μM), ML281 had no effect on the viability of KRAS-dependent cancer cells. These results are consistent with other recent reports using small-molecule STK33 inhibitors. Small molecules having different chemical structures and kinase-selectivity profiles are needed to fully understand the role of STK33 in KRAS-dependent cancers. In this regard, ML281 is a valuable addition to small-molecule probes of STK33.

SUBMITTER: Weiwer M

PROVIDER: S-EPMC3523537 | biostudies-literature | 2012 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

A Potent and Selective Quinoxalinone-Based STK33 Inhibitor Does Not Show Synthetic Lethality in KRAS-Dependent Cells.

Weïwer Michel M Spoonamore James J Wei Jingqiang J Guichard Boris B Ross Nathan T NT Masson Kristina K Silkworth Whitney W Dandapani Sivaraman S Palmer Michelle M Scherer Christina A CA Stern Andrew M AM Schreiber Stuart L SL Munoz Benito B

ACS medicinal chemistry letters 20121022 12

The KRAS oncogene is found in up to 30% of all human tumors. In 2009, RNAi experiments revealed that lowering mRNA levels of a transcript encoding the serine/threonine kinase STK33 was selectively toxic to KRAS-dependent cancer cell lines, suggesting that small-molecule inhibitors of STK33 might selectively target KRAS-dependent cancers. To test this hypothesis, we initiated a high-throughput screen using compounds in the Molecular Libraries Small Molecule Repository (MLSMR). Several hits were i ...[more]

PMID: 23256033

Similar Datasets

Project description:Many human oncogenes are challenging therapeutic targets. An alternative to direct targeting of oncogenes is to perform â??synthetic lethalityâ?? screens for genes that are essential only in the context of specific cancer-causing mutations. We used high-throughput RNA interference (RNAi) to identify synthetic lethal interactions in cancer cells harboring mutant KRAS, the most commonly mutated human oncogene. We find that cells that are dependent on mutant KRAS exhibit sensitivity to suppression of the serine/threonine kinase STK33 irrespective of tissue origin, whereas STK33 is not required by KRAS-independent cells. STK33 promotes cancer cell viability in a kinase activity-dependent manner by regulating the suppression of mitochondrial apoptosis mediated through S6K1-induced inactivation of the death agonist BAD selectively in mutant KRAS-dependent cells. These observations identify STK33 as a target for treatment of the broad spectrum of mutant KRAS-driven cancers, and demonstrate the potential of RNAi screens for discovering critical functional dependencies created by oncogenic mutations that may enable therapeutic intervention for cancers associated with â??undruggableâ?? genetic alterations. NOMO-1 and SKM-1 acute myeloid leukemia (AML) cells were stably transduced with different pLKO.1puro lentiviral shRNA vectors targeting STK33 or a nontargeting control shRNA. VSV-G-pseudotyped lentiviral particles were produced by cotransfection of 293T cells with pLKO.1 constructs and the compatible packaging plasmids pMD.G and pCMVR8.91. Virus was harvested 48 and 72 hours after transfection, cells were incubated with lentiviral supernatants for 30 hours, and infected cells were selected with 2 Âµg/ml puromycin. RNA was isolated after 2 days of puromycin selection and isolation of viable cells by density gradient centrifugation, and gene expression was profiled using GeneChip Human Genome U133 Plus 2.0 microarrays (Affymetrix). Fluorescence ratios were normalized according to the RMA algorithm, and data were filtered as previously described (Bullinger et al. Blood 110:1291-300, 2007) using the BRB-ArrayTools software package. For subsequent analyses, only probe sets with a p-value for the log intensity variation of less than 0.01 were included. Average linkage clustering was used for hierarchical clustering (distance measure, correlation uncentered), and results were visualized using TreeView (Eisen et al. Proc Natl Acad Sci USA 95:14863-14868, 1998). Differentially expressed genes (p < 0.005) were identified by â??class comparison analysisâ?? for paired samples (cell line transduced with an shRNA targeting STK33 versus cell line transduced with a control shRNA) using the BRB-ArrayTools software package (Version 3.3.0 Beta_3; http://linus.nci.nih.gov/BRB-ArrayTools.html) and R (Version 2.2.1; http://www.r-project.org). Screening for an enrichment of genes belonging to distinct BioCarta pathways in the different gene sets was performed with the BRB Pathway Comparison tool computing several statistics, including the Fisher (LS) statistic and the Kolmogorov-Smirnov (KS) statistic. A pathway was considered differentially regulated if the significance level was less than 0.005.

Dataset Information

A Potent and Selective Quinoxalinone-Based STK33 Inhibitor Does Not Show Synthetic Lethality in KRAS-Dependent Cells.

Publications

A Potent and Selective Quinoxalinone-Based STK33 Inhibitor Does Not Show Synthetic Lethality in KRAS-Dependent Cells.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets