Project description:The development of oral squamous cell carcinoma (OSCC) is a multistep process requiring the accumulation of genetic alterations. To identify genes responsible for OSCC development, we performed high-density single-nucleotide polymorphism array analysis and genome-wide gene expression profiling on OSCC tumors. These analyses identified "absent in melanoma (AIM2)" and "interferon-inducible gene 16 (IFI16)," mapped to the hematopoietic IFN-inducible nuclear proteins with 200-amino acid repeat (HIN-200) gene cluster in the amplified region of chromosome 1q23, with overexpression in OSCCs. AIM2 and IFI16 are cytoplasmic double-stranded DNA sensors for innate immunity and act as tumor suppressors in several human cancers. Knockdown of AIM2 or IFI16 in OSCC cells resulted in the suppression of cell growth and the induction of apoptosis, accompanied by the downregulation of NF-κB activation. Because all of the OSCC cell lines had impairment of p53 activity, wild-type p53 was introduced in p53-deficient OSCC cells, and as a result, the expression of wild-type p53 suppressed cell growth and induced apoptosis via suppression of NF-κB activity. Finally, the coexpression of AIM2 and IFI16 significantly enhanced cell growth in p53-deficient cells; in contrast, the expression of AIM2 and/or IFI16 in cells bearing wild-type p53 suppressed cell growth. Moreover, AIM2 and IFI16 synergistically enhanced NF-κB signaling in p53-deficient cells. Thus, expression of AIM2 and IFI16 may have oncogenic functions in OSCC cells inactivating p53 system. Copy number analysis of Affymetrix 250K SNP arrays was performed for 5 oral leukoplakia samples, 20 oral squamous cell carcinoma samples, and 8 oral squamous cell carcinoma cell lines.
Project description:The development of oral squamous cell carcinoma (OSCC) is a multistep process requiring the accumulation of genetic alterations. To identify genes responsible for OSCC development, we performed high-density single-nucleotide polymorphism array analysis and genome-wide gene expression profiling on OSCC tumors. These analyses identified "absent in melanoma (AIM2)" and "interferon-inducible gene 16 (IFI16)," mapped to the hematopoietic IFN-inducible nuclear proteins with 200-amino acid repeat (HIN-200) gene cluster in the amplified region of chromosome 1q23, with overexpression in OSCCs. AIM2 and IFI16 are cytoplasmic double-stranded DNA sensors for innate immunity and act as tumor suppressors in several human cancers. Knockdown of AIM2 or IFI16 in OSCC cells resulted in the suppression of cell growth and the induction of apoptosis, accompanied by the downregulation of NF-κB activation. Because all of the OSCC cell lines had impairment of p53 activity, wild-type p53 was introduced in p53-deficient OSCC cells, and as a result, the expression of wild-type p53 suppressed cell growth and induced apoptosis via suppression of NF-κB activity. Finally, the coexpression of AIM2 and IFI16 significantly enhanced cell growth in p53-deficient cells; in contrast, the expression of AIM2 and/or IFI16 in cells bearing wild-type p53 suppressed cell growth. Moreover, AIM2 and IFI16 synergistically enhanced NF-κB signaling in p53-deficient cells. Thus, expression of AIM2 and IFI16 may have oncogenic functions in OSCC cells inactivating p53 system.
Project description:We explored ALR function in a ligand-independent manner using a drug-inducible dimerization system in which ALRs were tagged with two FV domains that rapidly oligomerize upon addition of the drug AP1 We found that oligomerization of IFI16, PYHIN1, or MNDA did not result in any significant gene expression changes. Total RNA was isolated from BFP, IFI16-2xFV, PYHIN1-2xFV, or MNDA-2xFV-expressing THP1 cells mock-treated or treated with 30nM AP1 dimerizer drug for 4 or 12 hours.
Project description:We explored ALR function in a ligand-independent manner using a drug-inducible dimerization system in which ALRs were tagged with two FV domains that rapidly oligomerize upon addition of the drug AP1 We found that oligomerization of IFI16, PYHIN1, or MNDA did not result in any significant gene expression changes.
Project description:The formation of multimerized protein assemblies has emerged as a core component of immune signal amplification, yet the biochemical basis of this phenomenon remains unclear for many mammalian proteins within host defense pathways. The interferon-inducible protein 16 (IFI16) is a viral DNA sensor that oligomerizes upon binding to nuclear viral DNA and induces downstream antiviral responses. Here, we first generated oligomerization-incompetent IFI16 mutants that exhibit severely reduced ability to induce antiviral cytokine expression, suppress herpes simplex virus 1 (HSV-1) protein levels, and restrict viral progeny production. Using immunoaffinity purification and targeted mass spectrometry, we establish that oligomerization promotes IFI16 interactions with several proteins involved in transcriptional regulation, including PAF1C, UBTF, and ND10
Project description:Transcriptional profiling of human mesenchymal stem cells comparing normoxic MSCs cells with hypoxic MSCs cells. Hypoxia may inhibit senescence of MSCs during expansion. Goal was to determine the effects of hypoxia on global MSCs gene expression.
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:The human PYHIN proteins, AIM2, IFI16, IFIX, and MNDA, are regulators of immune response, transcription, apoptosis, and cell cycle. However, their protein interactions and underlying mechanisms remain largely uncharacterized. Here, we provide the interaction network for all PYHIN proteins. By designing a cell-based inducible system and integrating microscopy, immunoaffinity capture, quantitative mass spectrometry, and bioinformatics, we identified over 300 PYHIN interactions reflective of diverse functions.