pci-32765 and osimertinib

Osimertinib, a 3rd generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), is the first-line standard-of-care for EGFR-mutant non-small cell lung cancer (NSCLC) patients, while acquired drug resistance will inevitably occur. Interleukin-6 (IL-6) is a keystone cytokine in inflammation and cancer, while its role in osimertinib efficacy was unknown. Here we show that clinically, plasma IL-6 level predicts osimertinib efficacy in EGFR mutant NSCLC patients. Highly increased IL-6 levels are found in patients with acquired resistance to osimertinib. Addition of IL-6 or exogenous overexpression of IL-6 directly induces osimertinib resistance. Proteomics reveals LAMA5 (Laminin α5) and PTK2, protein tyrosine kinase 2, also called focal adhesion kinase (FAK), are activated in osimertinib-resistant cells, and siRNA knockdown of LAMA5 or PTK2 reverses IL-6-mediated osimertinib resistance. Next, using a large-scale compound screening, we identify ibrutinib as a potent inhibitor of IL-6 and Laminin α5/FAK signaling, which shows synergy with osimertinib in osimertinib-resistant cells with high IL-6 levels, but not in those with low IL-6 levels. In vivo, this combination inhibits tumor growth of xenografts bearing osimertinib-resistant tumors. Taken together, we conclude that Laminin α5/FAK signaling is responsible for IL-6-induced osimertinib resistance, which could be reversed by combination of ibrutinib and osimertinib.

Topics: Acrylamides; Adenine; Aniline Compounds; Carcinoma, Non-Small-Cell Lung; Drug Resistance, Neoplasm; ErbB Receptors; Focal Adhesion Kinase 1; Focal Adhesion Protein-Tyrosine Kinases; Humans; Interleukin-6; Laminin; Lung Neoplasms; Mutation; Piperidines

Covalent tyrosine kinase inhibitors (TKIs) ibrutinib and osimertinib are associated with cardiac arrhythmia. The interactions between these TKIs with CYP2J2 that is highly expressed in the human heart are unknown. In vitro metabolism experiments were performed to characterize CYP2J2-mediated metabolism of ibrutinib and osimertinib. Unbound distribution coefficient (K

Topics: Acrylamides; Adenine; Aniline Compounds; Arachidonic Acid; Cytochrome P-450 CYP2J2; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System; Humans; Indoles; Piperidines; Pyrimidines; Rivaroxaban

Covalent inhibition is a powerful strategy to develop potent and selective small molecule kinase inhibitors. Targeting the conserved catalytic lysine is an attractive method for selective kinase inactivation. We have developed novel, selective inhibitors of phosphoinositide 3-kinase δ (PI3Kδ) which acylate the catalytic lysine, Lys779, using activated esters as the reactive electrophiles. The acylating agents were prepared by adding the activated ester motif to a known selective dihydroisobenzofuran PI3Kδ inhibitor. Three esters were designed, including an acetate ester which was the smallest lysine modification evaluated in this work. Covalent binding to the enzyme was characterized by intact protein mass spectrometry of the PI3Kδ-ester adducts. An enzymatic digest coupled with tandem mass spectrometry identified Lys779 as the covalent binding site, and a biochemical activity assay confirmed that PI3Kδ inhibition was a direct result of covalent lysine acylation. These results indicate that a simple chemical modification such as lysine acetylation is sufficient to inhibit kinase activity. The selectivity of the compounds was evaluated against lipid kinases in cell lysates using a chemoproteomic binding assay. Due to the conserved nature of the catalytic lysine across the kinome, we believe the covalent inhibition strategy presented here could be applicable to a broad range of clinically relevant targets.

Topics: Acetylation; Acrylamides; Adenine; Afatinib; Amino Acid Sequence; Aniline Compounds; Catalysis; Catalytic Domain; Class I Phosphatidylinositol 3-Kinases; Humans; Lysine; Mass Spectrometry; Molecular Docking Simulation; Phosphoinositide-3 Kinase Inhibitors; Piperidines; Protein Binding; Protein Conformation; Substrate Specificity

Eight covalent tyrosine kinase inhibitors (TKIs) were investigated to determine the characteristics of their covalent binding to plasma proteins. The data revealed that their covalent binding to plasma proteins is of species difference. In addition to the reports on neratinib and pyrotinib, osimertinib, alflutinib, AST5902, and ibrutinib were confirmed to covalently bind to the Lys-190 of human serum albumin (HSA). Molecular docking was used to simulate the binding mode of TKIs to HSA. The results exhibited the non-covalent interactions between covalent TKIs and HSA, which stabilize the TKIs-HSA complex and explain the selectivity of covalent binding. The t

Topics: Acrylamides; Adenine; Aminoquinolines; Aniline Compounds; Animals; Binding Sites; Dogs; Haplorhini; Humans; Indoles; Lysine; Mice; Molecular Docking Simulation; Molecular Structure; Piperidines; Protein Kinase Inhibitors; Pyridines; Pyrimidines; Quinolines; Rabbits; Rats; Serum Albumin, Human