Epigenetics
Epigenetics research delves into the molecular mechanisms that control gene expression and cellular traits without altering the underlying DNA sequence. One crucial aspect of this field is the role of small molecules, which act as powerful regulators of epigenetic modifications. These small compounds, typically comprising a few dozen to a few hundred atoms, have emerged as essential tools in understanding and manipulating the epigenome.
- DNA Methylation Inhibitors: Small molecules like 5-azacytidine and 5-aza-2'-deoxycytidine are DNA methyltransferase inhibitors. They block the addition of methyl groups to DNA, leading to DNA demethylation. This can reactivate silenced genes, potentially offering therapeutic avenues for conditions like cancer.
- HDAC inhibitors: HDACs remove acetyl groups from histone proteins, contributing to gene repression. Small molecule HDAC inhibitors, such as Vorinostat and Romidepsin, can reverse this process by increasing histone acetylation, allowing genes to be more accessible for transcription. These inhibitors are being explored for cancer therapy and other conditions.
- Histone Methyltransferase Inhibitors: Small molecules like GSK126 inhibit specific histone methyltransferases, affecting histone methylation patterns. This can alter gene expression, making them promising candidates for cancer and other diseases with epigenetic dysregulation.
- RNA Modulators: Small molecules can also target non-coding RNAs involved in epigenetic regulation. For instance, small molecules called small interfering RNAs (siRNAs) can be designed to target and degrade specific long non-coding RNAs, influencing gene expression.
- Epigenetic Reader Domain Inhibitors: These small molecules target proteins that recognize and bind to specific epigenetic marks. Examples include inhibitors of bromodomain-containing proteins (BET inhibitors), which can disrupt gene regulation by interfering with protein-DNA interactions.
Small molecules in epigenetics research not only provide insights into the fundamental biology of gene regulation but also hold immense promise for developing novel therapeutics. Their ability to selectively modulate specific epigenetic marks and pathways has led to ongoing clinical trials and drug development efforts for various diseases, including cancer, neurological disorders, and inflammatory conditions. Understanding and harnessing the power of these small molecules is at the forefront of modern epigenetics research, offering new hope for precision medicine and targeted therapies.
3 key components involved in the regulation of epigenetic modifications
Epigenetics Writer
Epigenetics writers are enzymes responsible for adding chemical marks or modifications to DNA or histone proteins. These marks include DNA methylation (addition of methyl groups to DNA) and histone modifications (such as acetylation, methylation, phosphorylation, etc.).
Epigenetics Reader
Function: Epigenetics readers are proteins that can recognize and bind to specific epigenetic marks on DNA or histones. These reader proteins interpret the epigenetic code and facilitate downstream cellular processes, such as gene activation or repression.
Epigenetics Eraser
Function: Epigenetics erasers are enzymes responsible for removing or reversing epigenetic marks on DNA or histones. This process allows for the dynamic regulation of gene expression and the resetting of epigenetic states during various stages of development and in response to environmental changes.
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PARP-1 inhibitor
BYK204165 is a cell-permeable isoquinolinedione compound that potently and selectively inhibits poly (ADP-ribose) polymerase 1 (PARP1). -
PARP1 Inhibitor
EB 47 is a potent inhibitor of PARP1 with IC50 of 45 nM. -
PTPMT1 inhibitor
Alexidine is an alkyl bis(biguanide) antiseptic which has been used in mouthwashes to eliminate plaque forming microorganisms. -
HDAC6 inhibitor
TCS HDAC6 20b, selective inhibitor of histone deacetylase 6 (HDAC6). Inhibits HCT116 growth in combination with taxol. Also inhibits growth of MCF-7 cells stimulated by estrogen. -
PTP1B Inhibitor
TCS 401 is a selective inhibitor of protein-tyrosine phosphatase 1B (PTP1B) (Ki values are 0.29, 59, 560, 1100, > 2000, > 2000 and > 2000 μM for PTP1B, CD45 D1D2, PTPβ, PTPε D1, SHP-1, PTPα D1 and LAR D1D2 respectively). -
Calcineurin inhibitor
Cyclosporine is a calcineurin phosphatase pathway inhibitor, used as an immunosuppressant drug to prevent rejection in organ transplantation. -
HDAC/ACE inhibitor
Sinapinic acid (Sinapic acid) is a phenolic compound isolated from Hydnophytum formicarum Jack. Rhizome, acts as an inhibitor of HDAC, with an IC50 of 2.27 mM, and also inhibits ACE-I activity. Sinapinic acid posssess potent anti-tumor activity, induces apoptosis of tumor cells. -
JAK inhibitor
LY2784544 is identified as being highly selective for JAK2-V617F and has advanced into human clinical trials for the treatment of several myeloproliferative disorders. - Parthenolide ((-)-Parthenolide) is a sesquiterpene lactone which occurs naturally in the plant feverfew (Tanacetum parthenium).
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Aurora inhibitor
PHA-680632 is potent inhibitor of Aurora A, Aurora B and Aurora C with IC50 of 27 nM, 135 nM and 120 nM, respectively. It has 10- to 200-fold higher IC50 for FGFR1, FLT3, LCK, PLK1, STLK2, and VEGFR2/3. -
HDAC Inhibitor
Pyroxamide (NSC 696085) is a potent inhibitor of affinity-purified HDAC1 and causes the accumulation of acetylated core histones in MEL cells cultured with the agent. -
Aurora inhibitor
SNS-314 Mesylate is a potent and selective inhibitor of Aurora A, Aurora B and Aurora C with IC50 of 9 nM, 31 nM, and 3 nM, respectively. It is less potent to Trk A/B, Flt4, Fms, Axl, c-Raf and DDR2. Phase 1. -
HDAC inhibitor
Sodium butyrate (NaB, Butanoic acid sodium salt), sodium salt of butyric acid, is a histone deacetylase inhibitor and competitively binds to the zinc sites of class I and II histone deacetylases (HDACs). -
HDAC inhibitor
Valproic acid sodium salt (Sodium Valproate) is an HDAC inhibitor, with IC50 in the range of 0.5 and 2 mM, also inhibits HDAC1 (IC50, 400 μM), and induces proteasomal degradation of HDAC2. -
JAK2/FLT3 inhibitor
TG-101348 is an orally bioavailable, ATP-competitive and selective inhibitor of Janus-associated kinase 2 with potential antineoplastic activity. -
Aurora A Inhibitor
Aurora A Inhibitor I is a potent and selective inhibitor of Aurora A kinase (AurA), with IC50 values to be 3.4 nM (Aurora A) and unusually high selectivity 1000 fold against Aurora B; a useful tool compound for investigating the cellular role of Aurora A kinases.
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Aurora Inhibitor
CCT129202 is a representative of a structurally novel series of imidazopyridine small-molecule inhibitors of Aurora kinase activity. It shows high selectivity for the Aurora kinases over a panel of other kinases tested and inhibits proliferation in multiple cultured human tumor cell lines.
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HDAC inhibitor
Droxinostat is a selective inhibitor of HDAC3, HDAC6, and HDAC8 that shows comparable inhibition of HDAC6 and HDAC8 with IC50 = 2.47 and 1.46 μmol/L, respectively. -
Histone Demethylases Inhibitor
Methylstat is a potent inhibitor of histone demethylases, effectively suppressing the activity of these enzymes. It demonstrates notable anti-proliferative effects with minimal cytotoxicity, inducing apoptosis and causing cell cycle arrest at the G0/G1 phase. Methylstat enhances the expression of key regulatory proteins such as p53 and p21, and it also inhibits cytokine-induced angiogenesis. This compound serves as a valuable chemical probe for investigating the role of histone demethylation in cancer biology and angiogenesis-related research. -
Tip60 HAT Inhibitor
TH1834 dihydrochloride is a selective inhibitor of Tip60 (KAT5), a histone acetyltransferase involved in the regulation of gene expression and DNA repair. This compound has been shown to induce apoptosis and enhance DNA damage in breast cancer cells, demonstrating its potential as a therapeutic agent in cancer research. Importantly, TH1834 dihydrochloride does not inhibit the activity of the structurally related histone acetyltransferase MOF, suggesting a targeted approach in modulating histone acetylation and cellular responses. -
PIM Kinase Inhibitor
PIM-447 dihydrochloride is a potent and selective pan-PIM kinase inhibitor targeting PIM1, PIM2, and PIM3 with Ki values of 6, 18, and 9 pM, respectively. This compound exhibits significant antimyeloma activity and protective effects on bone tissue. PIM-447 dihydrochloride also induces apoptosis, making it a valuable tool for research into cancer therapies and bone disease studies. -
MLL1 Inhibitor
MM-401 TFA is a selective inhibitor of the MLL1 H3K4 methyltransferase, functioning primarily by disrupting the interaction between MLL1 and WDR5 (IC50 = 0.32 μM). This compound has demonstrated the capability to induce cell cycle arrest, promote apoptosis, and facilitate differentiation in various cell types. Its unique mechanism makes MM-401 TFA a valuable tool for investigating the role of MLL1 in MLL leukemia research. -
WDR5 Inhibitor
WDR5-IN-1 is a highly selective inhibitor of WD repeat domain 5 (WDR5), demonstrating a binding affinity (Kd) of less than 0.02 nM. It effectively inhibits the MLL1 histone methyltransferase activity with an IC50 of 2.2 nM, leading to reduced MYC recruitment at WDR5-displaced genes. This compound exhibits significant anti-proliferative effects in neuroblastoma (CHP-134) and Burkitt’s lymphoma (Ramos) cell lines, making it a valuable tool for research in cancer biology and epigenetics. -
PAD1 Inhibitor
D-Cl-amidine hydrochloride is a potent and selective inhibitor of protein arginine deiminase 1 (PAD1). This compound effectively modulates citrullination, a post-translational modification involved in various biological processes, including inflammation and autoimmunity. D-Cl-amidine hydrochloride is a valuable tool for research into the roles of PAD1 in disease mechanisms and therapeutic interventions. Its favorable toxicity profile enhances its utility in biochemical and cellular assays. -
JAK1 Inhibitor
Ivarmacitinib is a potent inhibitor of the Janus kinase 1 (JAK1) enzyme with notable selectivity against JAK2, JAK3, and Tyk2. This compound effectively inhibits JAK1-STAT3 phosphorylation and promotes apoptosis in hepatic stellate cells, highlighting its potential for anti-proliferative and anti-inflammatory research applications. Ivarmacitinib is valuable for studies focused on diseases involving the JAK-STAT signaling pathway. -
WDR5 Inhibitor
WDR5-IN-4 is a selective inhibitor of the WDR5 protein, which plays a crucial role in chromatin regulation. With a Kd value of 0.1 nM, WDR5-IN-4 effectively displaces WDR5 from chromatin, leading to decreased expression of associated genes and subsequent inhibition of translation, resulting in nucleolar stress. This compound demonstrates potential anti-cancer effects, making it a valuable tool for research into gene regulation and cancer therapeutics.
