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Acquired resistance to inhibitors of anaplastic lymphoma kinase (ALK) is a major clinical challenge for ALK fusion-positive non-small-cell lung cancer (NSCLC). In the absence of secondary ALK mutations, epigenetic reprogramming is one of the main mechanisms of drug resistance, as it leads to phenotype switching that occurs during the epithelial-to-mesenchymal transition (EMT). Although drug-induced epigenetic reprogramming is believed to alter the sensitivity of cancer cells to anticancer treatments, there is still much to learn about overcoming drug resistance. In this study, we used an in vitro model of ceritinib-resistant NSCLC and employed genome-wide DNA methylation analysis in combination with single-cell (sc) RNA-seq to identify cytidine deaminase (CDA), a pyrimidine salvage pathway enzyme, as a candidate drug target. CDA was hypomethylated and upregulated in ceritinib-resistant cells. CDA-overexpressing cells were rarely but definitively detected in the naïve cell population by scRNA-seq, and their abundance was increased in the acquired-resistance population. Knockdown of CDA had antiproliferative effects on resistant cells and reversed the EMT phenotype. Treatment with epigenome-related nucleosides such as 5-formyl-2′-deoxycytidine selectively ablated CDA-overexpressing resistant cells via accumulation of DNA damage. Collectively, our data suggest that targeting CDA metabolism using epigenome-related nucleosides represents a potential new therapeutic strategy for overcoming ALK inhibitor resistance in NSCLC.

The loss-of-function variants are thought to be associated with inflammation in the stomach. We here aimed to evaluate the extent and role of methylation at the

Background: Acquired resistance to inhibitors of anaplastic lymphoma kinase (ALK) is a major clinical challenge for ALK fusion–positive non-small-cell lung cancer (NSCLC). In the absence of secondary ALK mutations, epigenetic reprogramming is one of the main mechanisms of drug resistance as it leads to phenotype switching that occurs during the epithelial-to-mesenchymal transition (EMT). While drug-induced epigenetic reprogramming is believed to alter the sensitivity of cancer cells to anticancer treatments, there is still much to learn about overcoming drug resistance. Methods: We used an in vitro model of ceritinib-resistant NSCLC and employed genome-wide DNA methylation analysis in combination with single-cell (sc) RNA-seq to identify cytidine deaminase (CDA), a pyrimidine salvage pathway enzyme, as a candidate drug target. Molecular biology was used to characterize the role of CDA in drug resistance. Integrated analysis of scRNA-seq and scATAC-seq identified gene regulatory networks in resistant cells. Clinical relevance of CDA was evaluated using TCGA datasets, patient-derived cells, and tumor biopsies. Results: CDA was hypomethylated and upregulated in ceritinib-resistant cells. CDA-overexpressing cells were rarely but definitively detected in the na¨ıve cell population by scRNA-seq, and their abundance increased in the acquired-resistance population. Knockdown of CDA had antiproliferative e↵ects on resistant cells and reversed the EMT phenotype. Treatment with epigenome-related nucleosides such as 5-formyl-2’-deoxycytidine selectively ablated CDA-overexpressing resistant cells via accumulation of DNA damage. Conclusions: Targeting CDA metabolism using epigenome-related nucleosides represents a potential new therapeutic strategy for overcoming ALK-inhibitor resistance in NSCLC.

Background Although recent advances in high-throughput technology have provided many insights into gastric cancer (GC), few reliable biomarkers for diffuse-type GC have been identified. Here, we aim to identify a prognostic and predictive signature of diffuse-type GC heterogeneity. Methods We analyzed RNA-seq-based transcriptome data to identify a molecular signature in 150 gastric tissue samples including 107 diffuse-type GCs. The predictive value of the signature was verified using other diffuse-type GC samples in three independent cohorts (n = 466). Log-rank and Cox regression analyses were used to estimate the association between the signature and prognosis. The signature was also characterized by somatic variant analyses and tissue microarray analysis between diffuse-type GC subtypes. Results Transcriptomic profiling of RNA-seq data identified a signature which revealed distinct subtypes of diffuse-type GC: the intestinal-like (INT) and core diffuse-type (COD) subtypes. The signature showed high predictability and independent clinical utility in diffuse-type GC prognosis in other patient cohorts (HR 2.058, 95% CI 1.53–2.77, P = 1.76 × 10–6). Integrative mutational and gene expression analyses demonstrated that the COD subtype was responsive to chemotherapy, whereas the INT subtype was responsive to immunotherapy with an immune checkpoint inhibitor (ICI). Tissue microarray analysis showed the practical utility of IGF1 and NXPE2 for predicting diffuse-type GC heterogeneity. Conclusions We present a molecular signature that can identify diffuse-type GC patients who display different clinical behaviors as well as responses to chemotherapy or ICI treatment.

Approximately half of colorectal cancer (CRC) patients experience disease recurrence and metastasis, and these individuals frequently fail to respond to treatment due to their clinical and biological diversity. Here, we aimed to identify a prognostic signature consisting of a small gene group for precisely predicting CRC heterogeneity. We performed transcriptomic profiling using RNA-seq data generated from the primary tissue samples of 130 CRC patients. A prognostic index (PI) based on recurrence-associated genes was developed and validated in two larger independent CRC patient cohorts (n = 795). The association between the PI and prognosis of CRC patients was evaluated using Kaplan–Meier plots, log-rank tests, a Cox regression analysis and a RT-PCR analysis. Transcriptomic profiling in 130 CRC patients identified two distinct subtypes associated with systemic recurrence. Pathway enrichment and RT-PCR analyses revealed an eleven gene signature incorporated into the PI system, which was a significant prognostic indicator of CRC. Multivariate and subset analyses showed that PI was an independent risk factor (HR = 1.812, 95% CI = 1.342–2.448, P, Colorectal cancer: a tool to identify risk of recurrence A prognostic tool that searches for eleven genes associated with colorectal cancer recurrence shows promise in initial trials. The complexity of colorectal cancer (CRC) makes it challenging to treat. A significant number of patients relapse or experience metastasis even after surgical intervention, and fail to respond to post-surgical chemotherapy. Yong Sung Kim at the Korea Research Institute of Bioscience and Biotechnology, Daejeon, and Jin Cheon Kim from the University of Ulsan, Seoul, South Korea, and co-workers, conducted RNA-sequencing analysis on samples from 130 patients with CRC, 58 of whom had suffered relapse. They pinpointed eleven genes strongly associated with recurrence-free survival. They used these to develop a prognostic tool to identify high-risk patients and those more likely to respond poorly to chemotherapy. The tool was validated on a further 795 patients with CRC.

Human and mouse embryonic stem cells (ESCs) differ in terms of their pluripotency status, i.e., naive vs. primed. This affects various biological properties and leads to several technical hurdles for future clinical applications, such as difficulties in chimera formation, single-cell passaging, and gene editing. In terms of generating functional human tissues and organs via mammalian interspecies chimerism, a fluorescent chemical probe that specifically labels naive ESCs would help to isolate these cells and monitor their conversion. This study demonstrates that the fluorescent chemical probe compound of designation yellow 9 (CDy9) selectively stains naive, but not primed, mouse ESCs (mESCs). CDy9 entered cells via Slc13a5, a highly expressed membrane transporter in naive mESCs. Fluorescence-based cell sorting based on CDy9 staining successfully separated naive mESCs from primed mESCs. Mice generated using CDy9+ cells isolated during the conversion of mouse epiblast stem cells into naive mESCs exhibited coat color chimerism. Furthermore, CDy9 specifically stained cells in the inner cell mass of mouse embryos. These findings suggest that CDy9 is a useful tool to isolate functional naive mESCs.

Epigenetic dysregulation is a major driver of tumorigenesis. To identify tumor‐suppressive microRNAs repressed by DNA methylation in gastric cancer (GC), we analyzed the genome‐wide DNA methylation and microRNA expression profiles of EpCAM+/CD44+ GC cells. Among the set of microRNAs screened, miR‐1271 was identified as a microRNA repressed by DNA methylation in GC. Forced miR‐1271 expression substantially suppressed the growth, migration, and invasion of GC cells. To identify candidate target genes and signaling pathways regulated by miR‐1271, we performed RNA sequencing. Among the genes down‐regulated by miR‐1271, MAP2K1 (MEK1) was significantly repressed by miR‐1271, and the associated ERK/MAPK signaling pathway was also inhibited. TEAD4 was also repressed by miR‐1271, and the associated YAP1 signatures within genes regulated by miR‐1271 were significantly enriched. These findings uncovered MEK1 and TEAD4 as novel miR‐1271 targets and suggest that the epigenetic silencing of miR‐1271 is crucial for GC development.

Loss of functional β-cell mass is an essential feature of type 2 diabetes, and maintaining mature β-cell identity is important for preserving a functional β-cell mass. However, it is unclear how β-cells achieve and maintain their mature identity. Here we demonstrate a novel function of protein arginine methyltransferase 1 (PRMT1) in maintaining mature β-cell identity. Prmt1 knockout in fetal and adult β-cells induced diabetes, which was aggravated by high-fat diet–induced metabolic stress. Deletion of Prmt1 in adult β-cells resulted in the immediate loss of histone H4 arginine 3 asymmetric dimethylation (H4R3me2a) and the subsequent loss of β-cell identity. The expression levels of genes involved in mature β-cell function and identity were robustly downregulated as soon as Prmt1 deletion was induced in adult β-cells. Chromatin immunoprecipitation sequencing and assay for transposase-accessible chromatin sequencing analyses revealed that PRMT1-dependent H4R3me2a increases chromatin accessibility at the binding sites for CCCTC-binding factor (CTCF) and β-cell transcription factors. In addition, PRMT1-dependent open chromatin regions may show an association with the risk of diabetes in humans. Together, our results indicate that PRMT1 plays an essential role in maintaining β-cell identity by regulating chromatin accessibility.