3-Deazaneplanocin,DZNep

3-Deazaneplanocin is a highly potent inhibitor of S-adenosylhomocysteine hydrolase with Ki value of 0.05 nM [1].

3-Deazaneplanocin was synthesized as an inhibitor of S-adenosylhomocysteine hydrolase. It is an analog of adenosine and inhibits S-adenosylhomocysteine hydrolase through competing with the substrate, adenosine. 3-Deazaneplanocin was not so that potent in cell growth inhibition. 10 μM 3-Deazaneplanocin treatment resulted in moderate cell growth reduction in HL-60 cells. In HCC cell lines Huh1 and Huh7, 3-Deazaneplanocin inhibited growth and non-adherent sphere formation dose-dependently. It decreased the epithelial cell adhesion molecule EpCAMhigh fraction from 49.0% to 12.5% in Huh1 cells and from 44.4% to 11.6% in Huh7 cells. Moreover, in mice implanted with Huh7 cells, administration of 3-Deazaneplanocin suppressed tumor initiation and growth via directly affecting the growth and self-renewal of tumor-initiating cells [1, 2].

References:
[1] Glazer R I, Hartman K D, Knode M C, et al. 3-Deazaneplanocin: a new and potent inhibitor of S-adenosylhomocysteine hydrolase and its effects on human promyelocytic leukemia cell line HL-60. Biochemical and biophysical research communications, 1986, 135(2): 688-694.
[2] Chiba T, Suzuki E, Negishi M, et al. 3-Deazaneplanocin A is a promising therapeutic agent for the eradication of tumor-initiating hepatocellular carcinoma cells. International Journal of Cancer, 2012, 130(11): 2557-2567.

TP53 genomic status regulates sensitivity of gastric cancer cells to the histone methylation inhibitor 3-deazaneplanocin A (DZNep).[Pubmed:22675170]

Clin Cancer Res. 2012 Aug 1;18(15):4201-12.

PURPOSE: DZNep (3-deazaneplanocin A) depletes EZH2, a critical component of polycomb repressive complex 2 (PRC2), which is frequently deregulated in cancer. Despite exhibiting promising anticancer activity, the specific genetic determinants underlying DZNep responsiveness in cancer cells remain largely unknown. We sought to determine molecular factors influencing DZNep response in gastric cancer. EXPERIMENTAL DESIGN: Phenotypic effects of DZNep were evaluated in a panel of gastric cancer cell lines. Sensitive lines were molecularly interrogated to identify potential predictors of DZNep responsiveness. The functional importance of candidate predictors was evaluated using short hairpin RNA (shRNA) and siRNA technologies. RESULTS: DZNep depleted PRC2 pathway components in almost all gastric cancer lines, however, only a subset of lines exhibited growth inhibition upon treatment. TP53 genomic status was significantly associated with DZNep cellular responsiveness, with TP53 wild-type (WT) lines being more sensitive (P < 0.001). In TP53-WT lines, DZNep stabilized p53 by reducing ubiquitin conjugation through USP10 upregulation, resulting in activation of canonical p53 target genes. TP53 knockdown in TP53-WT lines attenuated DZNep sensitivity and p53 target activation, showing the functional importance of an intact p53 pathway in regulating DZNep cellular sensitivity. In primary human gastric cancers, EZH2 expression was negatively correlated with p53 pathway activation, suggesting that higher levels of EZH2 may repress p53 activity. CONCLUSION: Our results highlight an important role for TP53 genomic status in influencing DZNep response in gastric cancer. Clinical trials evaluating EZH2-targeting agents such as DZNep should consider stratifying patients with gastric cancer by their TP53 genomic status.

3-Deazaneplanocin A (DZNep), an inhibitor of the histone methyltransferase EZH2, induces apoptosis and reduces cell migration in chondrosarcoma cells.[Pubmed:24852755]

PLoS One. 2014 May 22;9(5):e98176.

OBJECTIVE: Growing evidences indicate that the histone methyltransferase EZH2 (enhancer of zeste homolog 2) may be an appropriate therapeutic target in some tumors. Indeed, a high expression of EZH2 is correlated with poor prognosis and metastasis in many cancers. In addition, 3-Deazaneplanocin A (DZNep), an S-adenosyl-L homocysteine hydrolase inhibitor which induces EZH2 protein depletion, leads to cell death in several cancers and tumors. The aim of this study was to determine whether an epigenetic therapy targeting EZH2 with DZNep may be also efficient to treat chondrosarcomas. METHODS: EZH2 expression was determined by immunohistochemistry and western-blot. Chondrosarcoma cell line CH2879 was cultured in the presence of DZNep, and its growth and survival were evaluated by counting adherent cells periodically. Apoptosis was assayed by cell cycle analysis, Apo2.7 expression using flow cytometry, and by PARP cleavage using western-blot. Cell migration was assessed by wound healing assay. RESULTS: Chondrosarcomas (at least with high grade) highly express EZH2, at contrary to enchondromas or chondrocytes. In vitro, DZNep inhibits EZH2 protein expression, and subsequently reduces the trimethylation of lysine 27 on histone H3 (H3K27me3). Interestingly, DZNep induces cell death of chondrosarcoma cell lines by apoptosis, while it slightly reduces growth of normal chondrocytes. In addition, DZNep reduces cell migration. CONCLUSION: These results indicate that an epigenetic therapy that pharmacologically targets EZH2 via DZNep may constitute a novel approach to treat chondrosarcomas.

3-Deazaneplanocin A (DZNep), an inhibitor of S-adenosylmethionine-dependent methyltransferase, promotes erythroid differentiation.[Pubmed:24492606]

J Biol Chem. 2014 Mar 21;289(12):8121-34.

EZH2, a core component of polycomb repressive complex 2 (PRC2), plays a role in transcriptional repression through histone H3 Lys-27 trimethylation and is involved in various biological processes, including hematopoiesis. It is well known that 3-deazaneplanocin A (DZNep), an inhibitor of S-adenosylmethionine-dependent methyltransferase that targets the degradation of EZH2, preferentially induces apoptosis in various hematological malignancies, suggesting that EZH2 may be a new target for epigenetic treatment. Because PRC2 participates in epigenetic silencing of a subset of GATA-1 target genes during erythroid differentiation, inhibition of EZH2 may influence erythropoiesis. To explore this possibility, we evaluated the impact of DZNep on erythropoiesis. DZNep treatment significantly induced erythroid differentiation of K562 cells, as assessed by benzidine staining and quantitative RT-PCR analysis for representative erythroid-related genes, including globins. When we evaluated the effects of DZNep in human primary erythroblasts derived from cord blood CD34-positive cells, the treatment significantly induced erythroid-related genes, as observed in K562 cells, suggesting that DZNep induces erythroid differentiation. Unexpectedly, siRNA-mediated EZH2 knockdown had no significant effect on the expression of erythroid-related genes. Transcriptional profiling of DZNep-treated K562 cells revealed marked up-regulation of SLC4A1 and EPB42, previously reported as representative targets of the transcriptional corepressor ETO2. In addition, DZNep treatment reduced the protein level of ETO2. These data suggest that erythroid differentiation by DZNep may not be directly related to EZH2 inhibition but may be partly associated with reduced protein level of hematopoietic corepressor ETO2. These data provide a better understanding of the mechanism of action of DZNep, which may be exploited for therapeutic applications for hematological diseases, including anemia.

Cell-based proteome profiling using an affinity-based probe (AfBP) derived from 3-deazaneplanocin A (DzNep).[Pubmed:23749335]

Chem Asian J. 2013 Aug;8(8):1818-28.

3-Deazaneplanocin A (DzNep), a global histone methylation inhibitor, has attracted significant interest in epigenetic research in recent years. The molecular mechanism of action and the cellular off-targets of DzNep, however, are still not well-understood. Our aim was to develop novel DzNep-derived small-molecule probes suitable to be used in live mammalian cells for identification of potential cellular targets of DzNep under physiologically relevant settings. In the current study, we have successfully designed, synthesized, and tested one such probe, called DZ-1. DZ-1 is a 'clickable' affinity-based probe (AfBP) derived from DzNep with minimal structural modifications. The probe was found to be highly cell-permeable, and possessed similar anti-apoptotic activities as DzNep in MCF-7 mammalian cells. Two additional control probes were made as negative labeling/pull-down probes in order to minimize false identification of background proteins due to unavoidable, intrinsic nonspecific photo-crosslinking reactions. All three probes were subsequently used for in-situ proteome profiling in live mammalian cells, followed by large-scale pull-down/LC-MS/MS analysis for identification of potential cellular protein targets that might interact with DzNep in native cellular environments. Our LC-MS/MS results revealed some highly enriched proteins that had not been reported as potential DzNep targets. These proteins might constitute unknown cellular off-targets of DzNep. Though further validation experiments are needed in order to unequivocally confirm these off-targets, our findings shed new light on the future use of DzNep as a validated chemical probe for epigenetic research and as a potential drug candidate for cancer therapy.