No abstract

Prostaglandin transporter (PGT) mediates prostaglandin (PG) catabolism and PG signal termination. The prostanoid PGE(2), which induces angiogenesis and vasodilation, is diminished in diabetic skin, suggesting that PGT up-regulation could be important in wound healing deficiency, typified by diabetic foot ulcer. We hypothesized that up-regulation of PGT in hyperglycemia could contribute to weakened PGE(2) signaling, leading to impaired angiogenesis and wound healing. In human dermal microvascular endothelial cells (HDMECs), exposure to hyperglycemia increased PGT expression and activity up to threefold, accompanied by reduced levels of PGE(2). Hyperglycemia reduced HDMEC migration by 50% and abolished tube formation. Deficits in PGE(2) expression, HDMEC migration, and tube formation could be corrected by treatment with the PGT inhibitor T26A, consistent with the idea that PGT hyperactivity is responsible for impairments in angiogenesis mediated by PG signaling. In vivo, PGT expression was profoundly induced in diabetes and by wounding, correlating with diminished levels of proangiogenic factors PGE(2) and VEGF in cutaneous wounds of diabetic mice. Pharmacological inhibition of PGT corrected these deficits. PGT inhibition shortened cutaneous wound closure time in diabetic mice from 22 to 16 days. This effect was associated with increased proliferation, re-epithelialization, neovascularization, and blood flow. These data provide evidence that hyperglycemia enhances PGT expression and activity, leading to diminished angiogenic signaling, a possible key mechanism underlying defective wound healing in diabetes.

Recently, two mutations in the promoter region of the TERT gene [À124C>T (C228T ) and À146C>T (C250T)] have been identified as widespread throughout cancer types and highly prevalent, with frequencies ranging from 40% to 70% in melanoma, bladder, liver, and central nervous system malignancies, such as glioblastoma. 10e12 These Supported by NIH grants R21CA198495 (D.P.), UH2CA206124 (D.P.), and CA016087 (I.O. and Y.S.). Disclosures: G.K.-N. owns stock in Bio-Rad Laboratories and is the Director of Scientific Affairs at Bio-Rad's Digital Biology Center. S.C. owns stock in Bio-Rad and was a bioinformatics manager at Bio-Rad when this work was performed. Bio-Rad prepared probes and primers for this work.

Mutational heterogeneity can contribute to therapeutic resistance in solid cancers. In melanoma, the frequencies of intertumoral and intratumoral heterogeneity are controversial. We examined mutational heterogeneity within individual patients with melanoma using multiplatform analysis of commonly mutated driver and nonpassenger genes. We analyzed paired primary and metastatic tumors from 60 patients and multiple metastatic tumors from 39 patients whose primary tumors were unavailable (n ¼ 271 tumors). We used a combination of multiplex SNaPshot assays, Sanger sequencing, mutation-specific PCR, or droplet digital PCR to determine the presence of BRAF V600 , NRAS Q61 , TERT e124C>T , and TERT e146C>T mutations. Mutations were detected in BRAF (39%), NRAS (21%), and/or TERT (78%). Thirteen patients had TERT mutant discordant tumors; seven of these had a single tumor with both TERT e124C>T and TERT e146C>T mutations present at different allele frequencies. Two patients had both BRAF and NRAS mutations; one had different tumors and the other had a single tumor with both mutations. One patient with a BRAF mutant primary lacked mutant BRAF in at least one of their metastases. Overall, we identified mutational heterogeneity in 18 of 99 patients (18%). These results suggest that some primary melanomas may be composed of subclones with differing mutational profiles. Such heterogeneity may be relevant to treatment responses and survival outcomes.