Human NFE2L2 (L30F mutant form) [His]

Purpose: The majority (70%) of the esophageal squamous cell carcinoma (ESCC) cases in the world occur in China, where radiation therapy is the most common treatment. Yet the majority of ESCC patients still relapse. Methods and Materials: To better understand the genetic basis of radiation therapy resistance for ESCC, we performed longitudinal, whole-exome sequencing throughout radiation therapy on 42 patient tumor samples, including single-cell whole-exome sequencing for 147 cells for 2 patients. Results: Significant allelic changes were observed during clinical irradiation, with 42 recurrent radioresponsive genes (sensitive and resistant) identified in multiple patients, including NOTCH1, MAML3, CDKN2A, NFE2L2, GAS2L2, OBSCN and TP53, with the last 3 genes implicated as radioresponsive in both bulk and single-cell whole-exome sequencing. Most (37/42) radioresponsive genes showed regional variegation in both radioresistant and radiosensitive mutations, with a paucity of resistant-only mutations (2.5%). A subset of sensitive mutations in 10 genes and resistant mutations in 18 genes defined a significantly improved prognosis and the shortest time for locoregional recurrence, respectively, indicating possible clinical utility. We also confirmed these significant mutational signatures in orthogonal Cancer Genome Atlas ESCC cohorts. Conclusions: Overall, our results quantify the allelic shifts underlying radioresponse in bulk and single-cell ESCC exomes for the first time, provide a temporal resolution to such mutational dynamics, and offer new therapeutic target genes and loci for esophageal and potentially other cancers. (C) 2020 Elsevier Inc. All rights reserved.

H2O2 mediates autocrine and paracrine signaling in the vasculature and can propagate endothelial dysfunction. However, it is not clear how endothelial cells withstand H2O2 exposure and promote H2O2-induced vascular remodeling. To understand the innate ability of endothelial cells for sustaining excess H2O2 exposure, we investigated the genotypic and functional regulation of redox systems in primary HUVECs following an H2O2 treatment. Primary HUVECs were exposed to transient H2O2 exposure and consistent H2O2 exposure. Following H2O2 treatments for 24, 48 and 72h, we measured O-2(-) production, mitochondrial membrane polarization (MMP), and gene expressions of pro-oxidative enzymes, peroxidase enzymes, and cytoprotective intermediates. Our results showed that the 24 h H2O2 exposure significantly increased O-2(-) levels, hyperpolarized MMP, and downregulated CAT, GPX1, TXNRD1, NFE2L2, ASK1, and ATF2 gene expression in HUVECs. At 72 h, HUVECs in both treatment conditions were shown to adapt to reduce O-2(-) levels and normalize MMP. An upregulation of GPX1, TXNRD1, and HMOX1 gene expression and a recovery of NFE2L2 and PRDX1 gene expression to control levels were observed in both consistent and transient treatments at 48 and 72 h. The response of endothelial cells to excess levels of H2O2 involves a complex interaction amongst O-2(-) levels, mitochondrial membrane polarization and anti- and pro-oxidant gene regulation. As a part of this response, HUVECs induce cytoprotective mechanisms including the expression of peroxidase and antioxidant enzymes along with the downregulation of pro-apoptotic genes. This adaptation assists HUVECs to withstand subsequent exposures to H2O2. (C) 2015 Elsevier Inc All rights reserved.