Polycomb group (PcG) protein-dependent histone methylation and ubiquitination drives chromatin compaction leading to reduced tumor suppressor expression and increased cancer cell survival. Green tea polyphenols and S-adenosylhomocysteine (AdoHcy) hydrolase inhibitors are important candidate chemopreventive agents. Previous studies indicate that (-)-epigallocatechin-3-gallate (EGCG), a potent green tea polyphenol, suppresses PcG protein level and skin cancer cell survival. Inhibition of AdoHcy hydrolase with 3-deazaneplanocin A (DZNep) inhibits methyltransferases by reducing methyl group availability. In the present study, we examine the impact of EGCG and DZNep cotreatment on skin cancer cell function. EGCG and DZNep, independently and in combination, reduce the level of PcG proteins including Ezh2, eed, Suz12, Mel18 and Bmi-1. This is associated with reduced H3K27me3 and H2AK119ub formation, histone modifications associated with closed chromatin. Histone deacetylase 1 level is also reduced and acetylated H3 formation is increased. These changes are associated with increased tumor suppressor expression and reduced cell survival and are partially reversed by vector-mediated maintenance of Bmi-1 level. The reduction in PcG protein level is associated with increased ubiquitination and is reversed by proteasome inhibitors, suggesting proteasome-associated degradation.
The transcriptional programs of ectothermic teleosts are directly influenced by water temperature. However, the cis- and trans-factors governing cold responses are not well characterized. We profiled transcriptional changes in eight zebrafish tissues exposed to mildly and severely cold temperatures using RNA-Seq. A total of 1943 differentially expressed genes (DEGs) were identified, from which 34 clusters representing distinct tissue and temperature response expression patterns were derived using the k-means fuzzy clustering algorithm. The promoter regions of the clustered DEGs that demonstrated strong co-regulation were analysed for enriched cis-regulatory elements with a motif discovery program, DREME. Seventeen motifs, ten known and seven novel, were identified, which covered 23% of the DEGs. Two motifs predicted to be the binding sites for the transcription factors Bcl6 and Jun, respectively, were chosen for experimental verification, and they demonstrated the expected cold-induced and cold-repressed patterns of gene regulation. Protein interaction modeling of the network components followed by experimental validation suggested that Jun physically interacts with Bcl6 and might be a hub factor that orchestrates the cold response in zebrafish. Thus, the methodology used and the regulatory networks uncovered in this study provide a foundation for exploring the mechanisms of cold adaptation in teleosts.
Transcriptional plasticity is a major driver of phenotypic differences between species. The lower temperature limit (LTL), namely the lower end of survival temperature, is an important trait delimiting the geographical distribution of a species, however, the genetic mechanisms are poorly understood. We investigated the inter-species transcriptional diversification in cold responses between zebrafish Danio rerio and tilapia Oreochromis niloticus, which were reared at a common temperature (28 °C) but have distinct LTLs. We identified significant expressional divergence between the two species in the orthologous genes from gills when the temperature cooled to the LTL of tilapia (8 °C). Five KEGG pathways were found sequentially over-represented in the zebrafish/tilapia divergently expressed genes in the duration (12 hour) of 8 °C exposure, forming a signaling cascade from metabolic regulation to apoptosis via FoxO signaling. Consistently, we found differential progression of apoptosis in the gills of the two species in which zebrafish manifested a delayed and milder apoptotic phenotype than tilapia, corresponding with a lower LTL of zebrafish. We identified diverged expression in 25 apoptosis-related transcription factors between the two species which forms an interacting network with diverged factors involving the FoxO signaling and metabolic regulation. We propose a genetic network which regulates LTL in fishes.
Long non-coding RNAs (lncRNAs) play key roles in colorectal carcinogenesis. Here, we aimed to identify the risk SNP-induced lncRNAs and to investigate their roles in colorectal carcinogenesis. First, we identified rs6695584 as the causative SNP in 1q41 locus. The A>G mutation of rs6695584 created a protein-binding motif of BATF, altered the enhancer activity, and subsequently activated lncSLCC1 expression. Further validation in two independent CRC cohorts confirmed the upregulation of lncSLCC1 in CRC tissues, and revealed that increased lncSLCC1 expression was associated with poor survival in CRC patients. Mechanistically, lncRNA-SLCC1 interacted with AHR and transcriptionally activated HK2 expression, the crucial enzyme in glucose metabolism, thereby driving the glycolysis pathway and accelerating CRC tumor growth. The functional assays revealed that lncSLCC1 induced glycolysis activation and tumor growth in CRC mediated by HK2. In addition, HK2 was upregulated in colorectal cancer tissues and positively correlated with lncSLCC1 expression and patient survival. Taken together, our findings reveal a risk SNP-mediated oncogene lncRNA-SLCC1 promotes CRC through activating the glycolysis pathway.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2025 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.