DNA methylation-mediated expression of zinc finger protein 615 affects embryonic development in Bombyx mori.

Cell division and differentiation after egg fertilization are critical steps in the development of embryos from single cells to multicellular individuals and are regulated by DNA methylation via its effects on gene expression. However, the mechanisms by which DNA methylation regulates these processes in insects remain unclear. Here, we studied the impacts of DNA methylation on early embryonic development in Bombyx mori. Genome methylation and transcriptome analysis of early embryos showed that DNA methylation events mainly occurred in the 5' region of protein metabolism-related genes. The transcription factor gene zinc finger protein 615 ( ZnF615) was methylated by DNA methyltransferase 1 (Dnmt1) to be up-regulated and bind to protein metabolism-related genes. Dnmt1 RNA interference (RNAi) revealed that DNA methylation mainly regulated the expression of nonmethylated nutrient metabolism-related genes through ZnF615. The same sites in the ZnF615 gene were methylated in ovaries and embryos. Knockout of ZnF615 using CRISPR/Cas9 gene editing decreased the hatching rate and egg number to levels similar to that of Dnmt1 knockout. Analysis of the ZnF615 methylation rate revealed that the DNA methylation pattern in the parent ovary was maintained and doubled in the offspring embryo. Thus, Dnmt1-mediated intragenic DNA methylation of the transcription factor ZnF615 enhances its expression to ensure ovarian and embryonic development.

Dynamic transcriptome analysis of Bombyx mori embryonic development.

Bombyx mori has been extensively studied but the gene expression control of its embryonic development is unclear. In this study, we performed transcriptome profiling of six stages of B. mori embryonic development using RNA sequencing (RNA-seq). A total of 12 894 transcripts were obtained from the embryos. Of these, 12 456 transcripts were shared among the six stages, namely, fertilized egg, blastoderm, germ-band, organogenesis, reversal period, and youth period stages. There were 111, 48, 41, 54, 77, and 107 transcripts specifically expressed during the six stages, respectively. By analyzing weighted gene correlation networks and differently expressed genes, we found that during embryonic development, many genes related to DNA replication, transcription, protein synthesis, and epigenetic modifications were upregulated in the early embryos. Genes of cuticle proteins, chitin synthesis-related proteins, and neuropeptides were more abundant in the late embryos. Although pathways of juvenile hormone and the ecdysteroid 20-hydroxyecdysone, and transcription factors were expressed throughout the embryonic development stages, more regulatory pathways were highly expressed around the organogenesis stage, suggesting more gene expression for organogenesis. The results of RNA-seq were confirmed by quantitative real-time polymerase chain reaction of 16 genes of different pathways. Nucleic acid methylation and seven sites in histone H3 modifications were confirmed by dot blot and western blot. This study increases the understanding of the molecular mechanisms of the embryonic developmental process and information on the regulation of B. mori development.

Maintenance chemotherapy is effective in patients with metastatic triple negative breast cancer after first-line platinum-based chemotherapy.

BACKGROUND: Platinum-based chemotherapy (PBCT) has gained an important position as a first-line treatment for metastatic triple-negative breast cancer (mTNBC). We assessed whether maintenance chemotherapy maintenance was superior to observation after first-line PBCT in patients with mTNBC. METHODS: A total of 265 patients with mTNBC who had exhibited non-PD after 4-6 cycles of firstline PBCT at the Fudan University Shanghai Cancer Center from January 2008 to April 2019 were retrospectively analyzed. 107 patients who did not receive additional treatment were defined as the control observation group, and the remaining 158 patients who continued to receive maintenance therapy were defined as the maintenance treatment group. RESULTS: The median progression-free survival (PFS) time in the maintenance group was 9.63 months, which was significantly longer than the PFS time of 7.47 months in the observation group (HR 0.49, 95% CI: 0.37-0.67, P<0.0001). The median overall survival (OS) of the observation group and the maintenance group was 25.37 months and 31.27 months, respectively (HR 0.65, 95% CI: 0.44-0.95, P=0.019). The survival benefit was still present after adjusting baseline characteristics. Moreover, multivariate analyses suggested that maintenance chemotherapy is an independent predictive factor for both PFS and OS. Interaction and stratified analyses showed no difference in the PFS with between the single-drug maintenance strategy, single agent or doublet group and the doublet-drug maintenance group. The most common adverse event in this study was hematologic toxicity. Except for hand-foot syndrome (0 vs. 7.6%, P=0.004), the incidence of other adverse events was not significantly different between the observation and maintenance groups. CONCLUSIONS: After achieving non-PD with the first-line PBCT in mTNBC patients, chemotherapy maintenance may provide OS benefit prior to the era of biologicals.

A new aromatic glycoside and its anti-proliferative activities from the leaves of Bergenia purpurascens.

Chemical investigation of the ethanolic extracts of the dried leaves of Bergenia purpurascens led to the isolation and identification of a new aromatic glycoside, 1-O-ß-D-glucopyranosyl-2-methoxy-3-hydroxyl-phenylethene (1), along with other 19 known compounds (2-20). The structure of compound 1 was determined by a detailed analysis using various analytical techniques, including 1D and 2D NMR. In vitro anti-proliferative activities of compound 1 on five human cancer cell lines were evaluated. The results showed that compound 1 possessed the most potent effects with the IC50 values of 14.36 ± 1.04 µM against T24 cells. The further bioactivity analysis showed that compound 1 induced apoptosis of T24 cells, and altered anti- and pro-apoptotic proteins, leading to mitochondrial dysfunction and activation of caspase-3 for causing cell apoptosis. The present investigation illustrated compound 1 might be used as a potential antitumour chemotherapy candidate.