Publications by authors named "William Bisson"

The complexity of cancer requires a comprehensive approach to understand its diverse manifestations and underlying mechanisms. Initially outlined by Hanahan and Weinberg in 2000 and updated in 2010, the hallmarks of cancer provide a conceptual basis for understanding inherent variability in cancer biology. Recent expansions have further elucidated additional hallmarks, including phenotypic plasticity and senescent cells.

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Non-destructive fluorophore diffusion across cell membranes to provide an unbiased fluorescence intensity readout is critical for quantitative imaging applications in live cells and tissues. Commercially available small-molecule fluorophores have been engineered for biological compatibility, imparting high water solubility by modifying rhodamine and cyanine dye scaffolds with multiple sulfonate groups. The resulting net negative charge, however, often renders these fluorophores cell-membrane-impermeant.

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The Anaplastic Lymphoma Kinase (ALK) is a therapeutic target for personalized medicine in selected cancers. Despite excellent clinical responses to ALK inhibitors, most patients develop drug resistance and relapse. New compounds with alternative binding modes are needed to overcome resistant mutants.

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The anaplastic lymphoma kinase (ALK) is abnormally expressed and hyperactivated in a number of tumors and represents an ideal therapeutic target. Despite excellent clinical responses to ALK inhibition, drug resistance still represents an issue and novel compounds that overcome drug-resistant mutants are needed. We designed, synthesized, and evaluated a large series of azacarbazole inhibitors.

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Much of what is known about the neurotrophic receptor tyrosine kinase (NTRK) genes in cancer was revealed through identification and characterization of activating Trk fusions across many tumor types. A resurgence of interest in these receptors has emerged owing to the realization that they are promising therapeutic targets. The remarkable efficacy of pan-Trk inhibitors larotrectinib and entrectinib in clinical trials led to their accelerated, tissue-agnostic US Food and Drug Administration (FDA) approval for adult and pediatric patients with Trk-driven solid tumors.

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The anti-hyperglycemic effect of metformin is believed to be caused by its direct action on signaling processes in hepatocytes, leading to lower hepatic gluconeogenesis. Recently, metformin was reported to alter the gut microbiota community in humans, suggesting that the hyperglycemia-lowering action of the drug could be the result of modulating the population of gut microbiota. However, the critical microbial signaling metabolites and the host targets associated with the metabolic benefits of metformin remained elusive.

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In its classical genomic mode of action, the aryl hydrocarbon receptor (AhR) acts as a ligand activated transcription factor regulating expression of target genes such as CYP1A1 and CYP1B1. Some ligands may also trigger more rapid nongenomic responses through AhR, including calcium signaling (Ca). In the present study we observed that pyrene induced a relatively rapid increase in intracellular Ca-concentrations ([Ca]) in human microvascular endothelial cells (HMEC-1) and human embryonic kidney cells (HEK293) that was attenuated by AhR-inhibitor treatment and/or transient AhR knockdown by RNAi.

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Rutaecarpine (RUT), evodiamine (EOD), and dehydroevodiamine (DHED) are the three main bioactive indoloquinazoline alkaloids isolated from , a widely prescribed traditional Chinese medicine. Here, the structure-activity relationships of these analogs for aryl hydrocarbon receptor (AHR) activation were explored by use of -deficient () mice, primary hepatocyte cultures, luciferase reporter gene assays, in silico ligand-docking studies, and metabolomics. In vitro, both mRNA analysis of AHR target genes in mouse primary hepatocytes and luciferase reporter assays in hepatocarcinoma cell lines demonstrated that RUT, EOD, and DHED significantly activated AHR, with an efficacy order of RUT > DHED > EOD.

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Medical castration that interferes with androgen receptor (AR) function is the principal treatment for advanced prostate cancer. However, clinical progression is universal, and tumors with AR-independent resistance mechanisms appear to be increasing in frequency. Consequently, there is an urgent need to develop new treatments targeting molecular pathways enriched in lethal prostate cancer.

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We previously reported that raloxifene, an estrogen receptor modulator, is also a ligand for the aryl hydrocarbon receptor (AhR). Raloxifene induces apoptosis in estrogen receptor-negative human cancer cells through the AhR. We performed structure-activity studies with seven raloxifene analogs to better understand the structural requirements of raloxifene for induction of AhR-mediated transcriptional activity and apoptosis.

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FICZ and TCDD, two high-affinity AhR ligands, are reported to have opposite effects on T cell differentiation with TCDD inducing regulatory T cells and FICZ inducing Th17 cells. This dichotomy has been attributed to ligand-intrinsic differences in AhR activation, although differences in sensitivity to metabolism complicate the issue. TCDD is resistant to AhR-induced metabolism and produces sustained AhR activation following a single dose in the μg/kg range, whereas FICZ is rapidly metabolized and AhR activation is transient.

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In patients with colorectal cancer (CRC) that metastasizes to the liver, there are several key goals for improving outcomes including early detection, effective prognostic indicators of treatment response, and accurate identification of patients at high risk for recurrence. Although new therapeutic regimens developed over the past decade have increased survival, there is substantial room for improvement in selecting targeted treatment regimens for the patients who will derive the most benefit. Recently, there have been exciting developments in identifying high-risk patient cohorts, refinements in the understanding of systemic vs localized drug delivery to metastatic niches, liquid biomarker development, and dramatic advances in tumor immune therapy, all of which promise new and innovative approaches to tackling the problem of detecting and treating the metastatic spread of CRC to the liver.

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Article Synopsis
  • Nitrated polycyclic aromatic hydrocarbons (NPAHs) and heterocyclic PAHs (HPAHs) are environmental pollutants with unclear health risks, prompting a study using zebrafish to assess their toxicity.
  • The study exposed zebrafish embryos to 27 NPAHs and 10 HPAHs, examining their effects on the aryl hydrocarbon receptor (AHR) and various toxic endpoints across different concentrations.
  • Results showed a spectrum of developmental toxicities linked to AHR activity and distinct gene expression patterns, indicating multiple potential mechanisms of action for these compounds.
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The objective of this study was to assess the underlying mechanisms of mango polyphenol decreased cell proliferation and tumor volume in ductal carcinoma in situ breast cancer. We hypothesized that mango polyphenols suppress signaling along the AKT/mTOR axis while up-regulating AMPK. To test this hypothesis, mango polyphenols (0.

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We report on the molecular interactions of the farnesoid X receptor (FXR) with prenylflavonoids, an emerging class of FXR modulators. FXR is an attractive therapeutic target for mitigating metabolic syndromes (MetS) because FXR activates the inhibitory nuclear receptor, small heterodimer partner (SHP), thereby inhibiting both gluconeogenesis and de novo lipogenesis. We and others have shown that xanthohumol (XN), the principal prenylflavonoid of the hop plant (Humulus lupulus L.

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Background: The current single-chemical-as-carcinogen risk assessment paradigm might underestimate or miss the cumulative effects of exposure to chemical mixtures, as highlighted in recent work from the Halifax Project. This is particularly important for chemical exposures in the low-dose range that may be affecting crucial cancer hallmark mechanisms that serve to enable carcinogenesis.

Objective: Could ongoing low-dose exposures to a mixture of commonly encountered environmental chemicals produce effects in concert that lead to carcinogenesis? A workshop held at the NIEHS in August 2015 evaluated the scientific support for the low-dose mixture hypothesis of carcinogenesis and developed a research agenda.

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We have identified a fixed nonsynonymous sequence difference between humans (Val381; derived variant) and Neandertals (Ala381; ancestral variant) in the ligand-binding domain of the aryl hydrocarbon receptor (AHR) gene. In an exome sequence analysis of four Neandertal and Denisovan individuals compared with nine modern humans, there are only 90 total nucleotide sites genome-wide for which archaic hominins are fixed for the ancestral nonsynonymous variant and the modern humans are fixed for the derived variant. Of those sites, only 27, including Val381 in the AHR, also have no reported variability in the human dbSNP database, further suggesting that this highly conserved functional variant is a rare event.

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Scope: Tannin-rich fruits have been evaluated as alternative prevention strategies for colorectal cancer based on their anti-inflammatory properties. This study compared tannin-rich preparations from mango (rich in gallotannins) and pomegranate (rich in ellagitannins) in the dextran sodium sulfate-induced colitis model.

Methods And Results: In rats, mango and pomegranate beverages decreased intestinal inflammation and the levels of pro-inflammatory cytokines in mucosa and serum.

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The farnesoid X receptor (FXR) regulates bile acid, lipid and glucose metabolism. Here we show that treatment of mice with glycine-β-muricholic acid (Gly-MCA) inhibits FXR signalling exclusively in intestine, and improves metabolic parameters in mouse models of obesity. Gly-MCA is a selective high-affinity FXR inhibitor that can be administered orally and prevents, or reverses, high-fat diet-induced and genetic obesity, insulin resistance and hepatic steatosis in mice.

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Acetylation is an important, reversible post-translational modification affecting histone and non-histone proteins with critical roles in gene transcription, DNA replication, DNA repair, and cell cycle progression. Key regulatory enzymes include histone deacetylase (HDACs) and histone acetyltransferases (HATs). Overexpressed HDACs have been identified in many human cancers, resulting in repressed chromatin states that interfere with vital tumor suppressor functions.

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Ligand activation of the aryl hydrocarbon (AHR) has profound effects upon the immunological status of the gastrointestinal tract, establishing and maintaining signaling networks, which facilitate host-microbe homeostasis at the mucosal interface. However, the identity of the ligand(s) responsible for such AHR-mediated activation within the gut remains to be firmly established. Here, we combine in vitro ligand binding, quantitative gene expression, protein-DNA interaction and ligand structure activity analyses together with in silico modeling of the AHR ligand binding domain to identify indole, a microbial tryptophan metabolite, as a human-AHR selective agonist.

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