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Small nucleotide variants in non-coding regions of the genome can alter transcriptional regulation, leading to changes in gene expression which can activate oncogenic gene regulatory networks. Melanoma is heavily burdened by non-coding variants, representing over 99% of total genetic variation, including the well-characterized TERT promoter mutation. However, the compendium of regulatory non-coding variants is likely still functionally under-characterized. We developed a pipeline to identify hotspots, i.e. recurrently mutated regions, in melanoma containing putatively functional non-coding somatic variants that are located within predicted melanoma-specific regulatory regions. We identified hundreds of statistically significant hotspots, including the hotspot containing the TERT promoter variants, and focused on a hotspot in the promoter of CDC20. We found that variants in the promoter of CDC20, which putatively disrupt an ETS motif, lead to lower transcriptional activity in reporter assays. Using CRISPR/Cas9, we generated an indel in the CDC20 promoter in human A375 melanoma cell lines and observed decreased expression of CDC20, changes in migration capabilities, increased growth of xenografts, and an altered transcriptional state previously associated with a more proliferative and less migratory state. Overall, our analysis prioritized several recurrent functional non-coding variants that, through downregulation of CDC20, led to perturbation of key melanoma phenotypes., (© 2023. The Author(s).)

Objective: To examine the effects of d-tagatose or stevia preloads on carbohydrate metabolism markers after an oral glucose load, as well as subjective and objective appetite in women with insulin resistance (IR)., Research Design and Methods: Randomized controlled crossover study. Women with IR without T2DM (n = 33; aged 23.4 ± 3.8; BMI 28.1 ± 3.4 kg × m -2 ) underwent three oral glucose loads (3 h each) on three different days. Ten min before oral glucose load, volunteers consumed a preload of 60 mL water (control), 60 mL water with stevia (15.3 mg), or d-tagatose (5000 mg). Serum glucose and C-peptide were evaluated at -10, 30-, 60-, 90-, 120-, and 180-min. Subjective appetite was determined with a visual analog scale. Food intake was measured at ad libitum buffet after 180 min., Results: C-peptide iAUC was significantly higher for stevia (median (IQR): 1033 (711-1293) ng × min × L -1 ) vs. d-tagatose (794 (366-1134) ng × min × L -1 ; P = 0.001) or control (730 (516-1078) ng × min × L -1 ; P = 0.012). At 30- and 60-min serum glucose was higher for stevia vs other conditions (P < 0.01). Volunteers reported greater satiety for stevia and d-tagatose vs. control at 60 min and greater desire to eat for stevia vs. control at 120- min (all P < 0.05). Objective appetite did not vary by condition (P = 0.06)., Conclusions: Our findings suggest that these NNS are not inert. Stevia intake produced an acute response on C-peptide release while increased serum glucose at earlier times. It is possible that NNS affects subjective but not objective appetite. This trial is registered at clinicaltrials.gov as NCT04327245., Clinical Trial Registry: NCT04327245., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to declare., (Copyright © 2022 European Society for Clinical Nutrition and Metabolism. Published by Elsevier Ltd. All rights reserved.)

Transcriptional and epigenetic characterization of melanocytes and melanoma cells isolated from their in vivo context promises to unveil key differences between these developmentally related normal and cancer cell populations. We therefore engineered an enhanced Danio rerio (zebrafish) melanoma model with fluorescently labeled melanocytes to allow for isolation of normal (wild type) and premalignant (BRAFV600E-mutant) populations for comparison to fully transformed BRAFV600E-mutant, p53 loss-of-function melanoma cells. Using fluorescence-activated cell sorting to isolate these populations, we performed high-quality RNA- and ATAC-seq on sorted zebrafish melanocytes vs. melanoma cells, which we provide as a resource here. Melanocytes had consistent transcriptional and accessibility profiles, as did melanoma cells. Comparing melanocytes and melanoma, we note 4128 differentially expressed genes and 56,936 differentially accessible regions with overall gene expression profiles analogous to human melanocytes and the pigmentation melanoma subtype. Combining the RNA- and ATAC-seq data surprisingly revealed that increased chromatin accessibility did not always correspond with increased gene expression, suggesting that though there is widespread dysregulation in chromatin accessibility in melanoma, there is a potentially more refined gene expression program driving cancerous melanoma. These data serve as a resource to identify candidate regulators of the normal vs. diseased states in a genetically controlled in vivo context., (© The Author(s) 2021. Published by Oxford University Press on behalf of Genetics Society of America.)