Project description:Epithelial-mesenchymal transition (EMT) plays a critical role in airway injury, repair, and structural remodeling. Although NFkB/RelA subnit is involved in late EMT-associated gene expression, RelA translocation is occurs later than early phases of IκB kinase (IKK)-depenedent gene expression. To investigate the hypothesis that IKK plays an independent mechanism in TGF-induced EMT, we conducted time-series proteomics and phosphoproteomics analysis of human airway epithelial cells in the absence or presence of a specific IKK inhibitor, BMS -345541.
Project description:Through the study of EGFR-mutant lung adenocarcinoma we show that NFkB signaling is rapidly engaged by EGFR oncogene inhibition to promote tumor cell persistence and therapy resistance. Unexpectedly, we found that EGFR oncogene inhibition induced an EGFR-TRAF2-RIP1-IKK complex that stimulated an NFkB-mediated transcriptional survival program. We identified a direct pharmacologic NFkB inhibitor, PBS-1086, that suppressed this adaptive survival program and increased both the magnitude and duration of initial EGFR TKI response in cellular and in vivo tumor models, including a novel patient-derived NSCLC xenograft. These findings unveil NFkB as a critical adaptive survival mechanism engaged in response to EGFR oncogene inhibition and identify PBS-1086 as a promising NFkB inhibitor to eliminate disease persistence and potentially prevent the emergence of resistance in patients. RNAseq analysis of 11-18 (EGFR-mutant lung adenocarcinoma) cells in the context of drug treatment with erlotinib and/or genetic or pharmacological inactivation of NFkB
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.
Project description:Through the study of EGFR-mutant lung adenocarcinoma we show that NFkB signaling is rapidly engaged by EGFR oncogene inhibition to promote tumor cell persistence and therapy resistance. Unexpectedly, we found that EGFR oncogene inhibition induced an EGFR-TRAF2-RIP1-IKK complex that stimulated an NFkB-mediated transcriptional survival program. We identified a direct pharmacologic NFkB inhibitor, PBS-1086, that suppressed this adaptive survival program and increased both the magnitude and duration of initial EGFR TKI response in cellular and in vivo tumor models, including a novel patient-derived NSCLC xenograft. These findings unveil NFkB as a critical adaptive survival mechanism engaged in response to EGFR oncogene inhibition and identify PBS-1086 as a promising NFkB inhibitor to eliminate disease persistence and potentially prevent the emergence of resistance in patients.