Archives

  • 2018-07
  • 2019-04
  • 2019-05
  • 2019-06
  • 2019-07
  • 2019-08
  • 2019-09
  • 2019-10
  • 2019-11
  • 2019-12
  • 2020-01
  • 2020-02
  • 2020-03
  • 2020-04
  • 2020-05
  • 2020-06
  • 2020-07
  • 2020-08
  • 2020-09
  • 2020-10
  • 2020-11
  • 2020-12
  • 2021-01
  • 2021-02
  • 2021-03
  • 2021-04
  • 2021-05
  • 2021-06
  • 2021-07
  • 2021-08
  • 2021-09
  • 2021-10
  • 2021-11
  • 2021-12
  • 2022-01
  • 2022-02
  • 2022-03
  • 2022-04
  • 2022-05
  • 2022-06
  • 2022-07
  • 2022-08
  • 2022-09
  • 2022-10
  • 2022-11
  • 2022-12
  • 2023-01
  • 2023-02
  • 2023-03
  • 2023-04
  • 2023-05
  • 2023-06
  • 2023-08
  • 2023-09
  • 2023-10
  • 2023-11
  • 2023-12
  • 2024-01
  • 2024-02
  • 2024-03
  • 2024-04

    • The inhibition of HDAC increases the level of

    2022-05-10

    The inhibition of HDAC increases the level of histone acetylation and consequently turns the chromatin to be loose and active, allowing multiple transcription factors to access to promoters of diverse genes including tumor suppressor genes []. As compound possessed potent HDAC inhibitory activity and showed considerable DNMT1 inhibitory potency, we further explored its effect on the acetylation of histones and the expression of relevant proteins in U937 cells via immunoblot analysis. Treated with for 12 h, U937 cells displayed a dose-dependent pattern of increased acetylation of histones H3K9 and H4K8 (B), confirming the inhibitory effectiveness of []. It has also been reported that some DNMT inhibitors, such as decitabine and SGI-1027, can reactivate the silenced tumor suppressor gene and increase its expression product p16 accordingly []. As expected, the results of western blot analysis (C) indicated that the expression of p16 in U937 cells treated with for 12 h was upregulated as the concentration of increased. P16, also known as multiple tumor suppressor 1, is an important negative feedback regulator of the walk through which can inhibit the activity of cyclin-dependent kinase 4 (CDK4) by competing with cyclin to bind CDK4, thereby hindering the cell cycle from G1 to S phase []. Therefore, we analyzed cell cycle arrest and apoptosis in U937 cells treated with using flow cytometry. Our cell cycle arrest analyses indicated that U937 cells were markedly arrested in the G1 phase (A) in response to treatment. As the concentration of gradually increased from 0 to 4.0 μmol/L, the percentage of U937 cells at G1 phase increased from 50.53% to 59.18%. Treated with at different concentrations for 48 h, the population of apoptotic U937 cells exhibited a dose-dependent increasing trend (B), suggesting that can trigger apoptosis process to inhibit U937 cell proliferation. Histone acetylation and DNA methylation affect gene expression by regulating chromatin remodeling, which is involved in all the hallmarks of tumor [,]. To investigate the complex anti-tumor mechanism of as a dual-target epigenetic inhibitor, including the potential functional mechanisms of -induced U937 cell cycle arrest and apoptosis, we conducted label-free quantitative proteomics analysis using Nano LC-MS/MS, profiling the proteome in U937 cells with or without treatment. To explore changes in proteomes at different drug treatment times, we collected cell lysates from -treated or control cells after 12 h, 24 h and 48 h as three groups. The concentrations of drug were uniformly set at 3 μmol/L to induce sufficient cellular changes and appropriate levels of cell death based on MTT assay results. Over 1800 nonredundant quantifiable proteins were identified in U937 cells treated in each group. Only proteins changed over 1.5 folds were selected for further analysis, whose numbers were 343, 307, and 429 after treated for 12 h, 24 h, and 48 h. In comparison, 115 differential proteins of the three groups were overlapping. Additionally, the 12 h treated protein group had 104 differential proteins that were different from those in the other two groups and 63 proteins were unique in the 24 h group, compared with 144 in the 48 h group (Fig. S1 in Supporting information). In short, through effects on epigenetic modifications, differentially modulated the protein expression in treated U937 cells over time. To elucidate the biological functions of these differentially expressed proteins, we analyzed the proteome data sets with the online analysis platform DAVID, classifying them into three enrichment gene ontology (GO) categories accordingly: biological processes, cellular composition, and molecular function. The enrichment analysis results revealed that in the biological processes category (A), significantly enriched proteins were related to termination of RNA polymerase II transcription (p = 1.10 × 10, 12 h), rRNA processing (p = 7.40 × 10, 24 h), mRNA splicing ( spliceosome) (p = 8.40 × 10, 48 h), nucleotide-excision repair, DNA gap filling (p = 1.50 × 10, 48 h), , which are processes relevant to gene transcription, translation, and DNA damage. DNA damage response, detection of DNA damage (p = 4.50 × 10, 48 h), was also a highly enriched category, in agreement with previous study that HDAC inhibitors can attenuate the levels of DNA damage response []. In the cellular composition analysis (B), mitochondria-associated proteins were significantly enriched by treatment, consistent with the observation that mitochondria are the primary intracellular compartments in response to acetylation-related events []. Interestingly, we found that treatment had profound effects on proteins of the extracellular exosome, which are suggested to play a role in cell-to-cell signaling, potentially influencing cancer development []. Furthermore, analysis of the molecular function category (C) indicated that these proteins are mostly involved in the binding of poly (A) RNA (p = 1.40 × 10, 24 h), protein (p = 1.60 × 10, 12 h), and ribosome (p = 1.40 × 10, 12 h), and structural constituent of ribosome (p = 1.90 × 10, 48 h).