ABSTRACT
Ten percent to 15% of all lung cancers are small-cell lung cancer (SCLC). SCLC usually grows and metastasizes before it is diagnosed and relapses rapidly upon treatment. Unfortunately, no new targeted agent has been approved in the past 30 years for patients with SCLC. The BET (bromodomain and extraterminal) proteins bind acetylated histones and recruit protein complexes to promote transcription initiation and elongation. BET proteins have been shown to regulate expression of key genes in oncogenesis, such as MYC, CCND2, and BCL2L1 Here, we demonstrate that approximately 50% of SCLC cell lines are exquisitely sensitive to growth inhibition by the BET inhibitor, ABBV-075. The majority of these SCLC cell lines underwent apoptosis in response to ABBV-075 treatment via induction of caspase-3/7 activity. ABBV-075 enhanced the expression of proapoptotic protein BIM and downregulated antiapoptotic proteins BCL2 and BCLxl to a lesser extent. Furthermore, BET inhibition increased BCL2-BIM complex, thus priming the cells for apoptosis. Indeed, strong synergy was observed both in vitro and in vivo when cotreating the cells with BET inhibitor and the BH3-mimetic, BCL2 inhibitor venetoclax (ABT-199). ABBV-075 interaction with venetoclax positively correlated with BCL2 expression. Taken together, our studies provide a rationale for treating SCLC with BET and BCL2 inhibitors in tumors with high BCL2 protein expression. Mol Cancer Ther; 16(8); 1511-20. ©2017 AACR.
Subject(s)
Apoptosis , Bridged Bicyclo Compounds, Heterocyclic/therapeutic use , Lung Neoplasms/drug therapy , Proteins/antagonists & inhibitors , Proto-Oncogene Proteins c-bcl-2/antagonists & inhibitors , Pyridones/therapeutic use , Small Cell Lung Carcinoma/drug therapy , Small Cell Lung Carcinoma/pathology , Sulfonamides/therapeutic use , Animals , Apoptosis/drug effects , Bcl-2-Like Protein 11/metabolism , Biomarkers, Tumor/metabolism , Bridged Bicyclo Compounds, Heterocyclic/pharmacology , Cell Line, Tumor , Female , Humans , Lung Neoplasms/pathology , Mice, SCID , Proto-Oncogene Proteins c-bcl-2/metabolism , Pyridones/pharmacology , Sulfonamides/pharmacology , Treatment Outcome , Xenograft Model Antitumor Assays , bcl-X Protein/metabolismABSTRACT
Four hinge-binding scaffolds have been explored for novel selective Aurora kinase inhibitors. The structure activity relationship, selectivity and pharmacokinetic profiles have been evaluated.
Subject(s)
Protein Kinase Inhibitors/chemical synthesis , Protein Serine-Threonine Kinases/antagonists & inhibitors , Animals , Aurora Kinases , Cell Line , Mice , Models, Molecular , Molecular Structure , Protein Kinase Inhibitors/pharmacology , Structure-Activity RelationshipABSTRACT
In an effort to discover Aurora kinase inhibitors, an HTS hit revealed an amide containing pyrrolopyrimidine compound. Replacement of the pyrrolopyrimidine residue with a thienopyrimidine moiety led to a series of potent and selective Aurora inhibitors.
