Article

Histone deacetylase turnover and recovery in sulforaphane-treated colon cancer cells: competing actions of 14-3-3 and Pin1 in HDAC3/SMRT corepressor complex dissociation/reassembly.

Linus Pauling Institute, Oregon State University, Corvallis, OR 97331-6512, USA.
Molecular Cancer (Impact Factor: 5.4). 05/2011; 10:68. DOI: 10.1186/1476-4598-10-68
Source: PubMed

ABSTRACT Histone deacetylase (HDAC) inhibitors are currently undergoing clinical evaluation as anti-cancer agents. Dietary constituents share certain properties of HDAC inhibitor drugs, including the ability to induce global histone acetylation, turn-on epigenetically-silenced genes, and trigger cell cycle arrest, apoptosis, or differentiation in cancer cells. One such example is sulforaphane (SFN), an isothiocyanate derived from the glucosinolate precursor glucoraphanin, which is abundant in broccoli. Here, we examined the time-course and reversibility of SFN-induced HDAC changes in human colon cancer cells.
Cells underwent progressive G2/M arrest over the period 6-72 h after SFN treatment, during which time HDAC activity increased in the vehicle-treated controls but not in SFN-treated cells. There was a time-dependent loss of class I and selected class II HDAC proteins, with HDAC3 depletion detected ahead of other HDACs. Mechanism studies revealed no apparent effect of calpain, proteasome, protease or caspase inhibitors, but HDAC3 was rescued by cycloheximide or actinomycin D treatment. Among the protein partners implicated in the HDAC3 turnover mechanism, silencing mediator for retinoid and thyroid hormone receptors (SMRT) was phosphorylated in the nucleus within 6 h of SFN treatment, as was HDAC3 itself. Co-immunoprecipitation assays revealed SFN-induced dissociation of HDAC3/SMRT complexes coinciding with increased binding of HDAC3 to 14-3-3 and peptidyl-prolyl cis/trans isomerase 1 (Pin1). Pin1 knockdown blocked the SFN-induced loss of HDAC3. Finally, SFN treatment for 6 or 24 h followed by SFN removal from the culture media led to complete recovery of HDAC activity and HDAC protein expression, during which time cells were released from G2/M arrest.
The current investigation supports a model in which protein kinase CK2 phosphorylates SMRT and HDAC3 in the nucleus, resulting in dissociation of the corepressor complex and enhanced binding of HDAC3 to 14-3-3 or Pin1. In the cytoplasm, release of HDAC3 from 14-3-3 followed by nuclear import is postulated to compete with a Pin1 pathway that directs HDAC3 for degradation. The latter pathway predominates in colon cancer cells exposed continuously to SFN, whereas the former pathway is likely to be favored when SFN has been removed within 24 h, allowing recovery from cell cycle arrest.

0 Bookmarks
 · 
166 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A high intake of brassica vegetables may be associated with a decreased chronic disease risk. Health promoting effects of Brassicaceae have been partly attributed to glucosinolates and in particular to their hydrolyzation products including isothiocyanates. In vitro and in vivo studies suggest a chemopreventive activity of isothiocyanates through the redox-sensitive transcription factor Nrf2. Furthermore, studies in cultured cells, in laboratory rodents, and also in humans support an anti-inflammatory effect of brassica-derived phytochemicals. However, the underlying mechanisms of how these compounds mediate their health promoting effects are yet not fully understood. Recent findings suggest that brassica-derived compounds are regulators of epigenetic mechanisms. It has been shown that isothiocyanates may inhibit histone deacetylase transferases and DNA-methyltransferases in cultured cells. Only a few papers have dealt with the effect of brassica-derived compounds on epigenetic mechanisms in laboratory animals, whereas data in humans are currently lacking. The present review aims to summarize the current knowledge regarding the biological activities of brassica-derived phytochemicals regarding chemopreventive, anti-inflammatory, and epigenetic pathways.
    Oxidative Medicine and Cellular Longevity 12/2013; 2013:964539. DOI:10.1155/2013/964539
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Histone deacetylase (HDAC) inhibitors are undergoing clinical trials as anticancer agents, but some exhibit resistance mechanisms linked to anti-apoptotic Bcl-2 functions, such as BH3-only protein silencing. HDAC inhibitors that reactivate BH3-only family members might offer an improved therapeutic approach. We show here that a novel seleno-α-keto acid triggers global histone acetylation in human colon cancer cells and activates apoptosis in a p21-independent manner. Profiling of multiple survival factors identified a critical role for the BH3-only member Bcl-2-modifying factor (Bmf). On the corresponding BMF gene promoter, loss of HDAC8 was associated with signal transducer and activator of transcription 3 (STAT3)/specificity protein 3 (Sp3) transcription factor exchange and recruitment of p300. Treatment with a p300 inhibitor or transient overexpression of exogenous HDAC8 interfered with BMF induction, whereas RNAi-mediated silencing of STAT3 activated the target gene. This is the first report to identify a direct target gene of HDAC8 repression, namely, BMF. Interestingly, the repressive role of HDAC8 could be uncoupled from HDAC1 to trigger Bmf-mediated apoptosis. These findings have implications for the development of HDAC8-selective inhibitors as therapeutic agents, beyond the reported involvement of HDAC8 in childhood malignancy.
    Cell Death & Disease 10/2014; 5:e1476. DOI:10.1038/cddis.2014.422 · 5.18 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background Histone deacetylase 3 (HDAC3) is overexpressed in cancers and its inhibition enhances anti-tumor chemotherapy. ZBP-89, a transcription factor, can induce pro-apoptotic Bak and reduce HDAC3 but the mechanism is unknown. Pin1, a molecular switch that determines the fate of phosphoproteins, is known to interact with HDAC3. The aim of this study was to investigate the mechanism how ZBP-89 downregulated HDAC3.Methods In this study, liver cells, Pin1-knockout Pin1¿/¿ and Pin1 wild-typed Pin+/+ cells were used to explore how ZBP-89 reduced HDAC3. The overexpression of ZBP-89 was achieved by infecting cells with Ad-ZBP-89, an adenoviral construct containing ZBP-89 gene. The role of NF-¿B was determined using CAY10576, MG132 and SN50, the former two being inhibitors of I¿B degradation and SN50 being an inhibitor of p65/p50 translocation. A xenograft tumor model was used to confirm the in vitro data.ResultsZBP-89 reduced HDAC3, and it could form a complex with I¿B and induce I¿B phosphorylation to inhibit I¿B. Furthermore, ZBP-89-mediated HDAC3 reduction was suppressed by I¿B degradation inhibitors CAY10576 and MG132 but not by p65/p50 translocation inhibitor SN50, indicating that I¿B decrease rather than the elevated activity of NF-¿B contributed to HDAC3 reduction. ZBP-89-mediated HDAC3 or I¿B reduction was significantly less obvious in Pin1¿/¿ cells compared with Pin1+/+ cells. In Ad-ZBP-89-infected Pin1+/+ cancer cells, Pin1 siRNA increased HDAC3 but decreased Bak, compared with cells without ZBP-89 infection. These findings indicate that Pin1 participates in ZBP-89-mediated HDAC3 downregulation and Bak upregulation. The cell culture result was confirmed by in vivo mouse tumor model experiments.ConclusionsZBP-89 attenuates HDAC3 by increasing I¿B degradation. Such attenuation is independent of NF-¿B activity but partially depends on Pin1. The novel pathway identified may help generate new anti-cancer strategy by targeting HDAC3 and its related molecules.
    Journal of Translational Medicine 01/2015; 13(1):23. DOI:10.1186/s12967-015-0382-7 · 3.99 Impact Factor

Full-text (2 Sources)

Download
46 Downloads
Available from
Jun 2, 2014