Project description:To develop our gene expression experiment, we have employed whole genome microarray expression profiling as a discovery platform to identify genes potentially regulated by the transcriptional coactivator KAT6B. Expression of KAT6B gene was downregulated in two human SCLC cell lines using two different short hairpin RNAs. RNAs from these modified cell lines were hybridized in Agilent platform.
Project description:To identify the immune peptides in SCLC tumour cells that can be processed and presented by HLA-I, we performed LC–MS/MS analysis on 11 SCLC cell lines, representing the heterogeneity of SCLC subtypes. Ten of the cell lines were confirmed positive for HLA-I, and one was HLA-I-deficient. To analyse cell surface antigens on the HLA-I-deficient cells, PBMCs isolated from healthy blood donors were treated with DMS53 cell lysate and matured into DCs to present the tumour cell antigens.
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.