Class IIa histone deacetylases (HDACs) play critical roles in vertebrate development and physiology, yet direct evidence of their intrinsic deacetylase activity and on substrate specificity regarding the peptide sequence is still missing. In this study, we designed and synthesized a combinatorial peptide library allowing us to profile class IIa HDACs sequence specificity at positions +3 through -3 from the central lysine modified by the well-accepted trifluoroacetyl function. Our data revealed a strong preference for bulky aromatic acids directly flanking the central trifluoroacetyllysine, while all class IIa HDACs disfavor positively charged residues and proline at the +1/-1 positions. The chemical nature of amino acid residues N-terminally to the central trifluoroacetyllysine has a more profound effect on substrate recognition as compared to residues located C-terminally. These findings were validated by designing selected favored and disfavored peptide sequences, with the favored ones are accepted with catalytic efficacy of 75 000 and 525 000 M-1 s-1 for HDAC7 and HDAC5, respectively. Results reported here could help in developing class IIa HDACs inhibitors and also in the search for new natural class IIa HDACs substrates.

• Klíčová slova
• class IIa histone deacetylases, deacetylation, peptide library, sequence specificity, substrates,
• MeSH
• histondeacetylasy * genetika   metabolismus   MeSH
• inhibitory histondeacetylas * farmakologie   MeSH
• peptidy MeSH
• sekvence aminokyselin MeSH
• substrátová specifita MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• histondeacetylasy * MeSH
• inhibitory histondeacetylas * MeSH
• peptidy MeSH

A high degree of developmental plasticity enables plants to adapt to continuous, often unfavorable and unpredictable changes in their environment. At the molecular level, adaptive advantages for plants are primarily provided by epigenetic machinery including DNA methylation, histone modifications, and the activity of noncoding RNA molecules. Using a mass spectrometry-based proteomic approach, we examined the levels of acetylated histone peptide forms in Arabidopsis plants with a loss of function of histone deacetylase 6 (HDA6), and in plants germinated in the presence of HDA inhibitors trichostatin A (TSA) and sodium butyrate (NaB). Our analyses revealed particular lysine sites at histone sequences targeted by the HDA6 enzyme, and by TSA- and NaB-sensitive HDAs. Compared with plants exposed to drugs, more dramatic changes in the overall profiles of histone post-translational modifications were identified in hda6 mutants. However, loss of HDA6 was not sufficient by itself to induce hyperacetylation to the maximum degree, implying complementary activities of other HDAs. In contrast to hda6 mutants that did not exhibit any obvious phenotypic defects, the phenotypes of seedlings exposed to HDA inhibitors were markedly affected, showing that the effect of these drugs on early plant development is not limited to the modulation of histone acetylation levels.

• Klíčová slova
• Arabidopsis thaliana, epigenetics, histone, mass spectrometry, post-translational modifications, sodium butyrate, trichostatin A,
• MeSH
• Arabidopsis genetika   růst a vývoj   MeSH
• histondeacetylasy genetika   MeSH
• histonový kód účinky léků   genetika   MeSH
• inhibitory histondeacetylas farmakologie   MeSH
• klíčení genetika   MeSH
• kyselina máselná farmakologie   MeSH
• kyseliny hydroxamové farmakologie   MeSH
• metylace DNA účinky léků   MeSH
• proteiny huseníčku antagonisté a inhibitory   genetika   MeSH
• proteomika * MeSH
• regulace genové exprese u rostlin MeSH
• semenáček účinky léků   genetika   MeSH
• umlčování genů MeSH
• vývoj rostlin účinky léků   genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• AT5G63110 protein, Arabidopsis MeSH Prohlížeč
• histondeacetylasy MeSH
• inhibitory histondeacetylas MeSH
• kyselina máselná MeSH
• kyseliny hydroxamové MeSH
• proteiny huseníčku MeSH
• trichostatin A MeSH Prohlížeč

We report toxic effects of a photoactivatable platinum(IV) complex conjugated with suberoyl-bis-hydroxamic acid in tumor cells. The conjugate exerts, after photoactivation, two functions: activity as both a platinum(II) anticancer drug and histone deacetylase (HDAC) inhibitor in cancer cells. This approach relies on the use of a Pt(IV) pro-drug, acting by two independent mechanisms of biological action in a cooperative manner, which can be selectively photoactivated to a cytotoxic species in and around a tumor, thereby increasing selectivity towards cancer cells. These results suggest that this strategy is a valuable route to design new platinum agents with higher efficacy for photodynamic anticancer chemotherapy.

• Klíčová slova
• DNA, antitumor agents, histone deacetylase inhibitors, photoactivation, platinum prodrugs,
• MeSH
• DNA chemie   MeSH
• fotochemie * MeSH
• genom MeSH
• histondeacetylasy metabolismus   MeSH
• platina chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA MeSH
• histondeacetylasy MeSH
• platina MeSH

The effects of the histone deacetylase inhibitors (HDACi) trichostatin A (TSA) and sodium butyrate (NaBt) were studied in A549, HT29 and FHC human cell lines. Global histone hyperacetylation, leading to decondensation of interphase chromatin, was characterized by an increase in H3(K9) and H3(K4) dimethylation and H3(K9) acetylation. The levels of all isoforms of heterochromatin protein, HP1, were reduced after HDAC inhibition. The observed changes in the protein levels were accompanied by changes in their interphase patterns. In control cells, H3(K9) acetylation and H3(K4) dimethylation were substantially reduced to a thin layer at the nuclear periphery, whereas TSA and NaBt caused the peripheral regions to become intensely acetylated at H3(K9) and dimethylated at H3(K4). The dispersed pattern of H3(K9) dimethylation was stable even at the nuclear periphery of HDACi-treated cells. After TSA and NaBt treatment, the HP1 proteins were repositioned more internally in the nucleus, being closely associated with interchromatin compartments, while centromeric heterochromatin was relocated closer to the nuclear periphery. These findings strongly suggest dissociation of HP1 proteins from peripherally located centromeres in a hyperacetylated and H3(K4) dimethylated environment. We conclude that inhibition of histone deacetylases caused dynamic reorganization of chromatin in parallel with changes in its epigenetic modifications.

• MeSH
• apoptóza účinky léků   MeSH
• buněčné jádro účinky léků   enzymologie   genetika   metabolismus   MeSH
• buněčné linie MeSH
• buněčný cyklus účinky léků   MeSH
• buňky HT-29 MeSH
• chromatin metabolismus   MeSH
• chromozomální proteiny, nehistonové antagonisté a inhibitory   metabolismus   MeSH
• histondeacetylasy metabolismus   MeSH
• histony metabolismus   MeSH
• homolog proteinu s chromoboxem 5 MeSH
• inhibitory enzymů farmakologie   MeSH
• inhibitory histondeacetylas * MeSH
• interfáze účinky léků   MeSH
• kyselina máselná farmakologie   MeSH
• kyseliny hydroxamové farmakologie   MeSH
• lidé MeSH
• malobuněčný karcinom enzymologie   metabolismus   patologie   MeSH
• nádorové buněčné linie MeSH
• nádory plic enzymologie   metabolismus   patologie   MeSH
• nádory tračníku enzymologie   metabolismus   patologie   MeSH
• plod MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chromatin MeSH
• chromozomální proteiny, nehistonové MeSH
• histondeacetylasy MeSH
• histony MeSH
• homolog proteinu s chromoboxem 5 MeSH
• inhibitory enzymů MeSH
• inhibitory histondeacetylas * MeSH
• kyselina máselná MeSH
• kyseliny hydroxamové MeSH
• trichostatin A MeSH Prohlížeč

Overexpression of histone deacetylases (HDACs), with consequent hypoacetylation of histones, is reportedly associated with transcriptional repression of tumour suppressor genes. Thus, inhibition of HDACs has emerged as a promising strategy in cancer therapy. In order to monitor the effects of potential HDAC inhibitors, a multi-level approach consisting of preliminary screening (measurement of HDAC activity and semi-quantitative evaluation of histone H4 modification profile by MALDI-TOF MS) and detailed analysis of histone modification forms (using 2-D AUT/AU PAGE and LC-ESI-IT MS) has been used in this study. The data obtained provide a global insight into the effects of HDAC inhibitors on the histone acetylation status that participates in gene transcription control. Using two example inhibitors, valproic acid sodium salt and entinostat, we show that similar levels of HDAC inhibition induced by different agents can lead to distinct rates of histone hyperacetylation, suggesting that except for the direct inhibition of HDACs, additional molecular mechanisms amplifying the response are likely to be involved in the inhibitory process. The approach used in our study makes it possible not only to follow the dynamics of individual histone modification forms, but also of their combined occurrence in the N-terminal fragment.

• MeSH
• acetylace účinky léků   MeSH
• benzamidy farmakologie   MeSH
• histondeacetylasy metabolismus   MeSH
• hmotnostní spektrometrie s elektrosprejovou ionizací MeSH
• inhibitory histondeacetylas farmakologie   MeSH
• kyselina valproová farmakologie   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• pyridiny farmakologie   MeSH
• spektrometrie hmotnostní - ionizace laserem za účasti matrice MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• benzamidy MeSH
• entinostat MeSH Prohlížeč
• histondeacetylasy MeSH
• inhibitory histondeacetylas MeSH
• kyselina valproová MeSH
• pyridiny MeSH

Carcinogenesis cannot be explained only by genetic alterations, but also involves epigenetic processes. Modification of histones by acetylation plays a key role in epigenetic regulation of gene expression and is controlled by the balance between histone deacetylases (HDAC) and histone acetyltransferases (HAT). HDAC inhibitors induce cancer cell cycle arrest, differentiation and cell death, reduce angiogenesis and modulate immune response. Mechanisms of anticancer effects of HDAC inhibitors are not uniform; they may be different and depend on the cancer type, HDAC inhibitors, doses, etc. HDAC inhibitors seem to be promising anti-cancer drugs particularly in the combination with other anti-cancer drugs and/or radiotherapy. HDAC inhibitors vorinostat, romidepsin and belinostat have been approved for some T-cell lymphoma and panobinostat for multiple myeloma. Other HDAC inhibitors are in clinical trials for the treatment of hematological and solid malignancies. The results of such studies are promising but further larger studies are needed. Because of the reversibility of epigenetic changes during cancer development, the potency of epigenetic therapies seems to be of great importance. Here, we summarize the data on different classes of HDAC inhibitors, mechanisms of their actions and discuss novel results of preclinical and clinical studies, including the combination with other therapeutic modalities.

• Klíčová slova
• anti-angiogenic effect, apoptosis, autophagy, cancer, cell cycle arrest, drug combinations, histone deacetylase inhibitors, histone deacetylases,
• MeSH
• acetylace účinky léků   MeSH
• antitumorózní látky farmakologie   terapeutické užití   MeSH
• apoptóza účinky léků   MeSH
• autofagie účinky léků   MeSH
• epigeneze genetická účinky léků   MeSH
• imunomodulace účinky léků   MeSH
• inhibitory angiogeneze farmakologie   terapeutické užití   MeSH
• inhibitory histondeacetylas farmakologie   terapeutické užití   MeSH
• klinické zkoušky jako téma MeSH
• kontrolní body buněčného cyklu účinky léků   MeSH
• lidé MeSH
• preklinické hodnocení léčiv MeSH
• protokoly antitumorózní kombinované chemoterapie škodlivé účinky   terapeutické užití   MeSH
• regulace genové exprese u nádorů účinky léků   MeSH
• signální transdukce účinky léků   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• antitumorózní látky MeSH
• inhibitory angiogeneze MeSH
• inhibitory histondeacetylas MeSH

Histone deacetylase 6 (HDAC6) is a unique member of the HDAC family of enzymes due to its complex domain organization and cytosolic localization. Experimental data point toward the therapeutic use of HDAC6-selective inhibitors (HDAC6is) for use in both neurological and psychiatric disorders. In this article, we provide side-by-side comparisons of hydroxamate-based HDAC6is frequently used in the field and a novel HDAC6 inhibitor containing the difluoromethyl-1,3,4-oxadiazole function as an alternative zinc-binding group (compound 7). In vitro isotype selectivity screening uncovered HDAC10 as a primary off-target for the hydroxamate-based HDAC6is, while compound 7 features exquisite 10,000-fold selectivity over all other HDAC isoforms. Complementary cell-based assays using tubulin acetylation as a surrogate readout revealed approximately 100-fold lower apparent potency for all compounds. Finally, the limited selectivity of a number of these HDAC6is is shown to be linked to cytotoxicity in RPMI-8226 cells. Our results clearly show that off-target effects of HDAC6is must be considered before attributing observed physiological readouts solely to HDAC6 inhibition. Moreover, given their unparalleled specificity, the oxadiazole-based inhibitors would best be employed either as research tools in further probing HDAC6 biology or as leads in the development of truly HDAC6-specific compounds in the treatment of human disease states.

• Klíčová slova
• histone deacetylase, inhibitor profiling, metallohydrolase, nanoBRET, tubulin/histone acetylation,
• MeSH
• acetylace MeSH
• histondeacetylasa 6 * antagonisté a inhibitory   MeSH
• histondeacetylasy * metabolismus   MeSH
• inhibitory histondeacetylas * chemie   farmakologie   MeSH
• kyseliny hydroxamové * chemie   farmakologie   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• oxadiazoly * chemie   farmakologie   MeSH
• posttranslační úpravy proteinů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• HDAC10 protein, human MeSH Prohlížeč
• histondeacetylasa 6 * MeSH
• histondeacetylasy * MeSH
• inhibitory histondeacetylas * MeSH
• kyseliny hydroxamové * MeSH
• oxadiazoly * MeSH

During the preclinical development of small molecule inhibitors, compounds or compound libraries are typically first screened using purified target enzymes in vitro to select candidates with high potency. In the later stages of the development, however, functional cell-based assays may provide biologically more relevant data. In this chapter, we describe a detailed protocol for determining the potency of inhibitors targeting human histone deacetylase 6 in complex cellular environments. Cells are first treated with a dilution series of tested compounds, cell lysates separated by SDS-PAGE, and electrotransferred to a blotting membrane. The inhibitor potency is then determined indirectly by quantifying the levels of acetylated tubulin as a surrogate readout.

• Klíčová slova
• Acetyl-histone, Acetyl-tubulin, Monoclonal antibody 6-11B-1, Quantitative Western blotting,
• MeSH
• acetylace MeSH
• histondeacetylasa 6 metabolismus   MeSH
• inhibitory histondeacetylas * farmakologie   MeSH
• lidé MeSH
• tubulin * metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• histondeacetylasa 6 MeSH
• inhibitory histondeacetylas * MeSH
• tubulin * MeSH

Histone deacetylase (HDAC) inhibitors are a group of anticancer drugs which cause growth arrest and apoptosis of several tumor cells. HDAC inhibitors have been also found to increase the anticancer efficacy of several treatment modalities i.e. chemotherapy or radiotherapy. Here, we review the literature on combinations of HDAC inhibitors both with ionizing radiation and with other drugs, highlighting DNA-damaging compounds. The results of numerous studies with several types of cancer cells discussed in this review demonstrate that HDAC inhibitors enhance the effect of DNA damaging agents, such as inhibitors of topoisomerases, inhibitors of DNA synthesis, DNA-intercalators and agents covalently modifying DNA (i.e. doxorubicin, etoposid, 5-fluorouracil, cisplatin, melphalan, temozolomide and ellipticine) or of irradiation. Hence, the use of HDAC inhibitors combined with these antitumor drugs or ionizing radiation is a promising tool which may make treatment of patients suffering from many types of cancer more efficient. Several molecular mechanisms are responsible for the observed higher sensitivity of tumor cells towards therapeutic agents elicited by HDAC inhibitors. These mechanisms are discussed also in this review.

• MeSH
• antitumorózní látky chemie   farmakologie   terapeutické užití   MeSH
• cílená molekulární terapie metody   MeSH
• DNA metabolismus   MeSH
• histondeacetylasy metabolismus   MeSH
• inhibitory histondeacetylas chemie   farmakologie   terapeutické užití   MeSH
• lidé MeSH
• nádory farmakoterapie   metabolismus   radioterapie   MeSH
• synergismus léků MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• antitumorózní látky MeSH
• DNA MeSH
• histondeacetylasy MeSH
• inhibitory histondeacetylas MeSH

The present study was designed to provide complementary information on the effects of histone deacetylase inhibitors (HDACi's) such as trichostatin A (TSA) and sodium valproate (VAP) on nuclei and nucleoli of leukemic myeloblasts represented by cultured Kasumi-1 cells. The number of apoptotic cells and bodies with characteristic chromatin condensation and fragmentation was greater after TSA treatment. However, in contrast to TSA, myeloblasts treated with VPA recovered and started to proliferate again. TSA-treated myeloblasts with a fine chromatin structure exhibited an intense phagocytosis of cell fragments. The decreased number and translocation of silver-stained proteins of nucleolus organiser regions (AgNORs) in large nucleoli of myeloblasts treated with HDACi's indicated that these cells entered apoptosis and/or ageing without preceding terminal maturation. The nucleolar asynchrony observed in an increased number of treated cells with both HDACi's studied here possibly represented myeloblasts resistant to such treatment. In conclusion, this study demonstrates that the chromatin structure and nucleoli visualised by simple cytochemical procedures provides useful information on the effects of HDACi's on myeloblasts and facilitated detection of these effects at the single cell level.

• MeSH
• apoptóza účinky léků   MeSH
• buněčné jádro účinky léků   enzymologie   MeSH
• histondeacetylasy metabolismus   MeSH
• inhibitory histondeacetylas * MeSH
• inhibitory proteas farmakologie   MeSH
• kyselina valproová farmakologie   MeSH
• kyseliny hydroxamové farmakologie   MeSH
• lidé MeSH
• myeloidní leukemie enzymologie   patologie   MeSH
• nádorové buněčné linie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• histondeacetylasy MeSH
• inhibitory histondeacetylas * MeSH
• inhibitory proteas MeSH
• kyselina valproová MeSH
• kyseliny hydroxamové MeSH
• trichostatin A MeSH Prohlížeč