Biology subjects

Keilhack, H.

Publications and source records attributed to Keilhack, H..

2 recordsLinked to original sources

bioRxiv2025

LINE-1 ORF1p is a shared and immunogenic antigen in cancer

BackgroundRecent clinical trials are beginning to show the potential for therapeutic cancer vaccines directed against tumor associated antigens. However, there is a limited set of well-defined antigens that are shared across tumors. Noncanonical coding elements in the genome that are usually silenced in normal cells potentially represent a rich source of "dark" antigens when expressed and presented to the immune system. LINE-1 elements are repetitive, virus-like genomic sequences that can copy themselves to new genomic loci, and which are reactivated in many cancers. In this study, we explore ORF1p, a protein encoded by LINE-1 elements, as a potential shared cancer vaccine antigen. MethodsWe assessed the tumor specificity of LINE-1 expression in large scale public RNA-seq data sets and in a curated database of public immunopeptidomics studies. We validated these findings using cell line and tissue data and performed an in vitro vaccination assay using healthy donor PBMCs to test the immunogenicity of ORF1p. ResultsWe found widespread RNA expression of LINE-1 across many tumor types with esophageal cancer showing the most highly elevated expression. We also found widespread MHC class I presentation of ORF1p-derived peptides in a range of tumor types, including esophageal cancer. We validated the tumor specific protein expression of ORF1p in a small set of 5 tumor, 5 matched normal, and 5 healthy esophageal samples. Finally, we demonstrated that dendritic cells pulsed with ORF1p peptides were able to induce interferon gamma production in healthy donor human T cells after repeated stimulation in vitro. ConclusionsWe present data demonstrating that dark antigens derived from LINE-1 elements are 1) expressed in a cancer tissue-specific manner, 2) detected in immunopeptidomics data (both publicly available and newly generated for this study) and 3) immunogenic in vitro. The tumor specificity and immunogenicity of ORF1p peptides point to their potential as a cancer vaccine antigen.

cancer biology↗

bioRxiv2021

Selective pharmaceutical inhibition of PARP14 mitigates allergen-induced IgE and mucus overproduction in a mouse model of pulmonary allergic response

The type 2 cytokines IL-4 and IL-13, which share use of an IL-4 receptor alpha chain and its nuclear induction of the transcription factor STAT6, are crucial in elicitation and maintenance of allergic conditions that include asthma. Prior work has shown a physical and functional association of STAT6 with PARP14, an ADP-ribosyl monotransferase. Moreover, elimination of all PARP14 expression by gene targeting led to altered recall antibody responses and attenuation of ovalbumin-specific allergic lung inflammation with no apparent health issues for mice lacking this protein. However, an unanswered question is whether or not inhibition of the catalytic function has any biological consequence since PARP14 has multiple functional domains apart from the portion that catalyzes ADP-ribosylation. As reported separately, iterative structural analyses and medicinal chemistry fostered the generation of a compound, RBN2759, that is highly selective in its inhibition of PARP14 with negligible impact on other members of the PARP gene family. We show here that administration of this compound to mice previously sensitized to the allergen Alternaria alternata achieved biochemically active levels and altered physiological responses to the antigen. These results show for the first time that in vivo administration of a specific inhibitor of the ADP-ribosyltransferase activity encoded by PARP14 is sufficient to alter biological responses. Specifically, the orally absorbable pharmaceutical compound decreased allergen-induced mucus, blunted the induced increases in circulating IgE, and prevented suppression of IgG2a. We conclude that the catalytic activity can contribute to pathogenesis in allergic processes and propose that other biological endpoints that depend on ADP-ribosylation by PARP14 can be targeted using selective inhibition.

immunology↗