Biology subjects

Delgoffe, G. M.

Publications and source records attributed to Delgoffe, G. M..

3 recordsLinked to original sources

bioRxiv2022

ATR kinase inhibition induces thymineless death in proliferating CD8+ T cells

ATR kinase is a central regulator of the DNA damage response (DDR) and cell cycle checkpoints. ATR kinase inhibitors (ATRis) combine with radiation to generate CD8+ T cell-dependent responses in mouse models of cancer. We show that ATRis induce CDK1-dependent origin firing across active replicons in CD8+ T cells activated ex vivo while simultaneously decreasing the activity of rate-limiting enzymes for nucleotide biosynthesis. These pleiotropic effects of ATRi induce deoxyuridine (dU) contamination in genomic DNA, R loops, RNA-DNA polymerase collisions, and type-1 interferons (IFN-1). Remarkably, thymidine rescues ATRi-induced dU contamination, cell death, and IFN-1 expression in proliferating CD8+ T cells. Thymidine also rescues ATRi-induced cancer cell death. We propose that ATRi-induced dU contamination contributes to dose-limiting leukocytopenia and inflammation in the clinic and CD8+ T cell dependent anti-tumor responses in mouse models. We conclude that ATR is essential to limit dU contamination in genomic DNA and IFN-1 expression.

cancer biology↗

bioRxiv2021

Excess dietary sugar impairs colonic epithelial regeneration in response to damage.

The colonic epithelium requires continuous renewal by intestinal stem cells (ISCs) to restore the barrier after damage and proliferation of epithelial cells is modulated by dietary metabolites. We demonstrate that mice fed a high sugar diet failed to repair colonic barrier damage, resulting in increased intestinal pathology. Culturing ISCs in excess sugar limited murine and human colonoid development, indicating that dietary sugar can directly affect colonic epithelial proliferation. Similarly, in vivo lineage tracing experiments and transcriptomic analysis indicated that dietary sugar impeded the proliferative potential of ISCs. ISCs and their immediate daughter cells predominantly rely on mitochondrial respiration for energy; however, metabolic analysis of colonic crypts revealed that a high sugar diet primed the epithelium for glycolysis without a commensurate increase in aerobic respiration. Colonoids cultured in high-glucose conditions accumulated glycolytic metabolites but not TCA cycle intermediates, indicating that the two metabolic pathways may not be coupled in proliferating intestinal epithelium. Accordingly, biochemically inducing pyruvate flux through the TCA cycle by inhibiting pyruvate dehydrogenase kinase rescued sugar-impaired colonoid development. Our results indicate that excess dietary sugar can directly inhibit epithelial proliferation in response to damage and may inform diets that better support the treatment of acute intestinal injury.

immunology↗

bioRxiv2021

Altered costimulatory signals and hypoxia support chromatin landscapes limiting the functional potential of exhausted T cells in cancer

Immunotherapy has changed cancer treatment with major clinical successes, but response rates remain low due in part to elevated prevalence of dysfunctional, terminally exhausted T cells. However, the mechanisms promoting progression to terminal exhaustion remain undefined. We profiled the histone modification landscape of tumor-infiltrating CD8 T cells throughout differentiation, finding terminally exhausted T cells possessed chromatin features limiting their transcriptional potential. Active enhancers enriched for bZIP/AP-1 transcription factor motifs lacked correlated gene expression, which were restored by immunotherapeutic costimulatory signaling. Epigenetic repression was also driven by an increase in histone bivalency, which we linked directly to hypoxia exposure. Our study is the first to profile the precise epigenetic changes during intratumoral differentiation to exhaustion, highlighting their altered function is driven by both improper costimulatory signals and environmental factors. These data suggest even terminally exhausted T cells remain poised for transcription in settings of increased costimulatory signaling and reduced hypoxia.

immunology↗