Sensitivity of Colorectal Cancer to Arginine Deprivation Therapy is Shaped by Differential Expression of Urea Cycle Enzymes

We thank Polaris Pharmaceuticals and Bio-Cancer Treatment for providing drugs and reagents. This work was supported by the Cancer Prevention Research Trust, with assistance from the Wellcome Trust Institutional Strategic Support Fund [097828/z/11/B], and Cancer Research UK in conjunction with the Department of Health as part of an Experimental Cancer Medicine Centre grant [C325/A15575]. C.A. was funded by a PhD fellowship from the Cancer Prevention Research Trust, S.S.A. was funded by a studentship from the Iraqi Government. We are thankful to John Bomalaski and Sara Galavotti for their critical reading of the manuscript and insightful suggestions. Finally, we are profoundly indebted to Professor Andreas Gescher for his constant support during the execution of this project and the writing of this manuscript.Peer reviewedPublisher PD

BRAF^V600E-mutated serrated colorectal neoplasia drives transcriptional activation of cholesterol metabolism

Abstract BRAF mutations occur early in serrated colorectal cancers, but their long-term influence on tissue homeostasis is poorly characterized. We investigated the impact of short-term (3 days) and long-term (6 months) expression of Braf V600E in the intestinal tissue of an inducible mouse model. We show that Braf V600E perturbs the homeostasis of intestinal epithelial cells, with impaired differentiation of enterocytes emerging after prolonged expression of the oncogene. Moreover, Braf V600E leads to a persistent transcriptional reprogramming with enrichment of numerous gene signatures indicative of proliferation and tumorigenesis, and signatures suggestive of metabolic rewiring. We focused on the top-ranking cholesterol biosynthesis signature and confirmed its increased expression in human serrated lesions. Functionally, the cholesterol lowering drug atorvastatin prevents the establishment of intestinal crypt hyperplasia in Braf V600E -mutant mice. Overall, our work unveils the long-term impact of Braf V600E expression in intestinal tissue and suggests that colorectal cancers with mutations in BRAF might be prevented by statins

Regulation of Heme oxygenase-1 induction : involvement in cancer chemoprevention

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Effects of Coronary Artery Disease-Associated Variants on Vascular Smooth Muscle Cells

10.1161/CIRCULATIONAHA.121.058389CIRCULATION14612917-92

Influence of a Coronary Artery Disease-Associated Genetic Variant on FURIN Expression and Effect of Furin on Macrophage Behavior.

OBJECTIVE: Genome-wide association studies have revealed a robust association between genetic variation on chromosome 15q26.1 and coronary artery disease (CAD) susceptibility; however, the underlying biological mechanism is still unknown. The lead CAD-associated genetic variant (rs17514846) at this locus resides in the FURIN gene. In advanced atherosclerotic plaques, furin is expressed primarily in macrophages. We investigated whether this CAD-associated variant alters FURIN expression and whether furin affects monocyte/macrophage behavior. APPROACH AND RESULTS: A quantitative reverse transcription polymerase chain reaction analysis showed that leukocytes from individuals carrying the CAD risk allele of rs17514846 had increased FURIN expression. A chromatin immunoprecipitation assay revealed higher RNA polymerase II occupancy in the FURIN gene in mononuclear cells of individuals carrying this allele. A reporter gene assay in transiently transfected monocytes/macrophages indicated that the CAD risk allele had higher transcriptional activity than the nonrisk allele. An analysis of isogenic monocyte cell lines created by CRISPR-mediated genome editing showed that isogenic cells with the A/A genotype for rs17514846 had higher FURIN expression levels than the isogenic cells with the C/C genotype. An electrophoretic mobility shift assay exhibited preferential binding of a nuclear protein to the risk allele. Studies of monocytes/macrophages with lentivirus-mediated furin overexpression or shRNA-induced furin knockdown showed that furin overexpression promoted monocyte/macrophage migration, increased proliferation, and reduced apoptosis whereas furin knockdown had the opposite effects. CONCLUSIONS: Our study shows that the CAD-associated genetic variant increases FURIN expression and that furin promotes monocyte/macrophage migration and proliferation while inhibiting apoptosis, providing a biological mechanism for the association between variation at the chromosome 15q26.1 locus and CAD risk

Sulfate metabolites provide an intracellular pool for resveratrol generation and induce autophagy with senescence

The phytochemical resveratrol has been shown to exert numerous health benefits in preclinical studies, but its rapid metabolism and resulting poor bioavailability may limit translation of these effects to humans. Resveratrol metabolites might contribute to in vivo activity through regeneration of the parent compound. We present quantitation of sulfate and glucuronide conjugates of resveratrol in human plasma and tissue after repeated ingestion of resveratrol by volunteers and cancer patients, respectively. Subsequent pharmacokinetic characterization of a mixture of resveratrol-3-O-sulfate and resveratrol-4′-O-sulfate in mice showed that these metabolites are absorbed orally but have low bioavailabilities of ~14 and 3%, respectively. Sulfate hydrolysis in vivo liberated free resveratrol, which accounted for ~2% of the total resveratrol species present in mouse plasma. Monosulfate metabolites were also converted to the parent in human colorectal cells. The extent of cellular uptake was dependent on specific membrane transporters and dictated antiproliferative activity. Sulfate metabolites induced autophagy and senescence in human cancer cells; these effects were abrogated by inclusion of a sulfatase inhibitor, which reduced intracellular resveratrol. Together, our findings suggest that resveratrol is delivered to target tissues in a stable sulfate-conjugated form and that the parent compound is gradually regenerated in selected cells and may give rise to the beneficial effects in vivo. At doses considered to be safe in humans, resveratrol generated via this route may be of greater importance than the unmetabolized form

Effects of Coronary Artery Disease-Associated Variants on Vascular Smooth Muscle Cells

BackgroundGenome-wide association studies have identified many genetic loci that are robustly associated with coronary artery disease (CAD). However, the underlying biological mechanisms are still unknown for most of these loci, hindering the progress to medical translation. Evidence suggests that the genetic influence on CAD susceptibility may act partly through vascular smooth muscle cells (VSMCs).MethodsWe undertook genotyping, RNA sequencing, and cell behavior assays on a large bank of VSMCs (n>1499). Expression quantitative trait locus and splicing quantitative trait locus analyses were performed to identify genes with an expression that was influenced by CAD-associated variants. To identify candidate causal genes for CAD, we ascertained colocalizations of VSMC expression quantitative trait locus signals with CAD association signals by performing causal variants identification in associated regions analysis and the summary data-based mendelian randomization test. Druggability analysis was then performed on the candidate causal genes. CAD risk variants were tested for associations with VSMC proliferation, migration, and apoptosis. Collective effects of multiple CAD-associated variants on VSMC behavior were estimated by polygenic scores.ResultsApproximately 60% of the known CAD-associated variants showed statistically significant expression quantitative trait locus or splicing quantitative trait locus effects in VSMCs. Colocalization analyses identified 84 genes with expression quantitative trait locus signals that significantly colocalized with CAD association signals, identifying them as candidate causal genes. Druggability analysis indicated that 38 of the candidate causal genes were druggable, and 13 had evidence of drug-gene interactions. Of the CAD-associated variants tested, 139 showed suggestive associations with VSMC proliferation, migration, or apoptosis. A polygenic score model explained up to 5.94% of variation in several VSMC behavior parameters, consistent with polygenic influences on VSMC behavior.ConclusionsThis comprehensive analysis shows that a large percentage of CAD loci can modulate gene expression in VSMCs and influence VSMC behavior. Several candidate causal genes identified are likely to be druggable and thus represent potential therapeutic targets