ABSTRACT
(-)-Epigallocatechin-3-gallate (EGCG) is the primary active ingredient in green tea and has been used for cancer prevention in clinical trials. The anti-tumor effects of EGCG stem from its ability to inhibit the activities of many oncoproteins, such as AKT, VEGFR, STAT3, and mutant p53. However, the clinical efficacy of EGCG is unsatisfactory. How to improve the anti-tumor effects of EGCG is an open question. Here we report that EGCG inhibits the tumor suppressive Hippo signaling pathway and activates downstream YAP in colorectal cancer (CRC) cells. Activation of YAP impedes the anti-tumor effects of EGCG. YAP blockade increases the sensitivity of CRC cells to EGCG treatment.
ABSTRACT
DNA modification is a naturally occurring DNA modification in prokaryotic and eukaryotic organisms and is involved in several biological processes. Although genome-wide methylation has been studied in many insects, the understanding of global and genomic DNA methylation during insect early embryonic development, is lacking especially for insect diapause. In this study, we analyzed the relationship between DNA methylomes and transcriptomes in diapause-destined eggs compared to diapause-terminated eggs in the silkworm, Bombyx mori (B. mori). The results revealed that methylation was sparse in this species, as previously reported. Moreover, methylation levels in diapause-terminated eggs (HCl-treated) were 0.05% higher than in non-treated eggs, mainly due to the contribution of CG methylation sites. Methylation tends to occur in the coding sequences and promoter regions, especially at transcription initiation sites and short interspersed elements. Additionally, 364 methylome- and transcriptome-associated genes were identified, which showed significant differences in methylation and expression levels in diapause-destined eggs when compared with diapause-terminated eggs, and 74% of methylome and transcriptome associated genes showed both hypermethylation and elevated expression. Most importantly, Kyoto Encyclopaedia of Genes and Genomes (KEGG) analyses showed that methylation may be positively associated with Bombyx mori embryonic development, by regulating cell differentiation, metabolism, apoptosis pathways and phosphorylation. Through analyzing the G2/M phase-specific E3 ubiquitin-protein ligase (G2E3), we speculate that methylation may affect embryo diapause by regulating the cell cycle in Bombyx mori. These findings will help unravel potential linkages between DNA methylation and gene expression during early insect embryonic development and insect diapause.
Subject(s)
Bombyx/genetics , DNA Methylation , Diapause, Insect/genetics , Epigenome , Transcriptome , Animals , Bombyx/embryology , Bombyx/physiology , Embryonic Development/genetics , Female , Insect Proteins , Ovum , PhosphorylationABSTRACT
DNA methylation is one of the most widespread epigenetic marks and has been linked to insect development, especially influencing embryonic development. However, the regulation of DNA methylation in silkworm embryonic development and diapause remain to investigate. In this study, reverse-transcription quantitative polymerase chain reaction was performed to identify the expression level of Bombyx mori DNA methyltransferases (BmDNMTs) 1 and 2 ( BmDnmt1 and BmDnmt2) in different tissues, different embryonic developmental stages, and different strains of the silkworm. The results showed that BmDNMTs were the most highly expressed during embryonic development, especially at early embryonic stages. In particular, the expression of BmDNMTs was significantly upregulated in diapause-terminated eggs by HCl treatment. Moreover, tissue distribution showed that BmDnmt2 was highly expressed in testis and ovary, and BmDnmt1 was highly expressed in testis. This study contributes to understanding the correlation of DNA methylation occurs with embryogenesis and gametogenesis in insect, meanwhile, it provides a research orientation to further analyze the role of DNA methylation in diapause initiation and termination in insect embryonic development.
