• Proceedings of the Korean Society of Applied Pharmacology
• /
• 2003.11a
• /
• pp.90-90
• /
• 2003

The acetylation of histone is one of the mechanisms involved in the regulation of gene expression and is tightly controlled by two core enzymes, histone acetyltransferase (HAT) and deacetylase (HDAC). There are several reports that imbalance of HAT and HDAC activity is associated with abnormal behavior of the cells in morphology, cell cycle, differentiation, and carcinogenesis. Recently, an increasing number of structurally diverse HDAC inhibitors have been identified that inhibit proliferation and induce differentiation and/or apoptosis of tumor cells in vivo and in vitro. In this study, we have investigated the effects of novel HDAC inhibitors, IN2001 on ER positive and ER negative human breast cancer cell lines. The growth inhibition, cell cycle arrest and apoptosis of cells by HDAC inhibitors were determined using SRB assay, DNA fragmentation, and flow cytometry. We found that IN 2001 as well as Trichostatin A inhibited cell growth dose-dependently in both ER positive and ER negative human breast cancer cell lines. The growth inhibition with HDAC inhibitors was associated with profound morphological change. The result of cell cycle analysis after 24 h exposure of IN2001 showed G2-M cell cycle arrest in MCF-7 cell and apoptosis in T47D and MDA-MB-231 cell. In summary, IN2001 has antiproliferative effect on human breast cancer cells regardless of the expression of estrogen receptor. These findings heights the possibility of developing HDAC inhibitors as potential anticancer therapeutic agents for the treatment of breast cancer.

• Proceedings of the Korea Society of Environmental Toocicology Conference
• /
• 2003.10a
• /
• pp.180-180
• /
• 2003

The acetylation of histone is one of the mechanisms involved in the regulation of gene expression and is tightly controlled by two core enzymes, histone acetyltransferase (HAT) and deacetylase (HDAC). There are several reports that imbalance of HAT and HDAC activity is associated with abnormal behavior of the cells in morphology, cell cycle, differentiation, and carcinogenesis. Recently, an increasing number of structurally diverse HDAC inhibitors have been identified that inhibit proliferation and induce differentiation and/or apoptosis of tumor cells in vivo and in vitro. In this study, we have investigated the effects of novel HDAC inhibitors, IN2001 on ER positive and ER negative human breast cancer cell lines. The growth inhibition, cell cycle arrest and apoptosis of cells by HDAC inhibitors were determined using SRB assay, DNA fragmentation, and flow cytometry. We found that IN 2001 as well as Trichostatin A inhibited cell growth dose-dependently in both ER Positive and ER negative human breast cancer cell lines. The growth inhibition with HDAC inhibitors was associated with profound morphological change. The result of cell cycle analysis after 24 h exposure of IN2001 showed G2-M cell cycle arrest in MCF-7 cell and apoptosis in T47B and MDA-MB-231 cell. In summary, IN2001 has antiproliferative effect on human breast cancer cells regardless of the expression of estrogen receptor. These findings heights the possibility of developing HDAC inhibitors as potential anticancer therapeutic agents for the treatment of breast cancer.

• Journal of Radiopharmaceuticals and Molecular Probes
• /
• v.6 no.2
• /
• pp.165-170
• /
• 2020

Histone Deacetylases (HDACs) are enzymes that have control gene expression regulation and cell state. In additions, inhibitions of HDACs are associated with growth arrest, differentiation, or apoptosis of tumor cell. Thus HDAC inhibition is one of the interesting biological targets. A variety of HDAC inhibitors has been developed by many scientists, and some of chemical structures related with HDAC inhibitors were modified to give radiolabeled HDAC inhibitors for positron emission tomography (PET) study. In this highlight review, the development of radiolabeled HDAC inhibitors for PET study are described.

• The Korean Journal of Physiology and Pharmacology
• /
• v.28 no.1
• /
• pp.83-91
• /
• 2024

Hypoxia-inducible factor-1 alpha (HIF-1α) is a transcription factor activated under hypoxic conditions, and it plays a crucial role in cellular stress regulation. While HIF-1α activity is essential in normal tissues, its presence in the tumor microenvironment represents a significant risk factor as it can induce angiogenesis and confer resistance to anti-cancer drugs, thereby contributing to poor prognoses. Typically, HIF-1α undergoes rapid degradation in normoxic conditions via oxygen-dependent degradation mechanisms. However, certain cancer cells can express HIF-1α even under normoxia. In this study, we observed an inclination toward increased normoxic HIF-1α expression in cancer cell lines exhibiting increased HDAC6 expression, which prompted the hypothesis that HDAC6 may modulate HIF-1α stability in normoxic conditions. To prove this hypothesis, several cancer cells with relatively higher HIF-1α levels under normoxic conditions were treated with ACY-241, a selective HDAC6 inhibitor, and small interfering RNAs for HDAC6 knockdown. Our data revealed a significant reduction in HIF-1α expression upon HDAC6 inhibition. Moreover, the downregulation of HIF-1α under normoxic conditions decreased zinc finger E-box-binding homeobox 1 expression and increased E-cadherin levels in lung cancer H1975 cells, consequently suppressing cell invasion and migration. ACY-241 treatment also demonstrated an inhibitory effect on cell invasion and migration by reducing HIF-1α level. This study confirms that HDAC6 knockdown and ACY-241 treatment effectively decrease HIF-1α expression under normoxia, thereby suppressing the epithelial-mesenchymal transition. These findings highlight the potential of selective HDAC6 inhibition as an innovative therapeutic strategy for lung cancer.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.5
• /
• pp.1487-1493
• /
• 2013

Based on the finding that the 2-aminobenzamido group of MS-275 plays a crucial role in inhibiting HDACs through chelation of zinc existing at the active site of HDAC enzymes, novel N-(2-hydroxyphenyl)arylsulfonamide derivatives were synthesized for their potential ability to inhibit HDACs and evaluated for anticancer activity against human breast cancer cell line (MCF-7). Although the synthesized arylsulfonamides have failed to significantly inhibit total HDACs activity, phenyl carbamate-linked arylsulfonamide 10 and benzyl thiocarbamate-linked arylsulfonamide 15 exhibited good anticancer activities, which were only 4.3- and 3.6-fold lower anticancer activities, respectively, than MS-275 that is undergoing phase II clinical trials. These results suggest that these compounds may act as a selective HDAC inhibitor and probably N-(2-hydroxyphenyl) sulfamoyl group may play an important role in interacting with HDAC enzymes through chelation of zinc ion.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 2001.11a
• /
• pp.110-110
• /
• 2001

Histone deacetylase(HDAC), a neuclear enzyme that regulates gene trascription and the assembly of newly synthesized chromatin, has received much attention in recent literature. The explosion of activity in this field has yielded the cloning of a mammalian gene which encodes a complementary histone acetyl trasferases. Several cyclic tetrapeptide inhibitors of HDAC has been reported to affect the hyperacetylation of mammalian and plant histones. Apicidin, a natural product HDAC inhibitor recently isolated at Merck Research Laboratories, induces therapeutic applications as a broad spectrum antiprotozoal agent to multi-drug resistant malaria and a potential antitumor agnet. The biological activity of apicidin appears to be attributable to inhibition of apicocomplexan HDAC at low nanomolar concentrations.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.6
• /
• pp.1891-1896
• /
• 2011

On the basis of potent HDAC-inhibitory activity and anticancer activity of SAHA, novel SAHA derivatives 3a-d and 7 with a bulky cap such as p-dimethylaminophenyl, 4-phenylaminophenyl, 4-phenyloxyphenyl, 9H-fluorenyl or naphthalenyl ring were synthesized starting from the corresponding aryl amines or naphthalenyl acetic acid using an EDC-mediated amide coupling reaction in the presence of HOBt followed by a nucleophilic addition-elimination reaction with hydroxylamine. Compounds 3b, 3c and 3d showed more potent inhibitory activity on total HDACs (14~27-fold), HDAC1 (8~15-fold), HDAC2 (1.3~25-fold) and HDAC7 (1~3-fold) and more potent anticancer activity (2~22-fold) against MCF-7, MDA-MB-231, MCF-7/Dox, MCF-7/Tam, SK-OV-3, LNCaP and PC3 human cancer cell lines than SAHA.

• Environmental Analysis Health and Toxicology
• /
• v.27
• /
• pp.10.1-10.7
• /
• 2012

Objectives: In recent years, a number of structurally diverse Histone deacetylase (HDAC) inhibitors have been identified and these HDAC inhibitors induce growth arrest, differentiation and/or apoptosis of cancer cells in vitro and in vivo. This study aimed at investigating the antitumor activity of newly synthesized HDAC inhibitor, 3-(4-dimethylamino phenyl)-N-hydroxy-2-propenamide (IN-2001) using human breast cancer cells. Methods: We have synthesized a new HDAC inhibitor, IN-2001, and cell proliferation inhibition assay with this chemical in estrogen receptor-positive human breast cancer MCF-7 cells. Cell cycle analysis on MCF-7 cells treated with IN-2001 was carried out by flow cytometry and gene expression was measured by RT-PCR. Results: In MCF-7 cells IN-2001 showed remarkable anti-proliferative effects in a dose- and time-dependent manner. In MCF-7 cells, IN-2001 showed a more potent growth inhibitory effect than that of suberoylanilide hydroxamic acid. These growth inhibitory effects were related to the cell cycle arrest and induction of apoptosis. IN-2001 showed accumulation of cells at $G_2$/M phase and of the sub-$G_1$ population in a time-dependent manner, representing apoptotic cells. IN-2001-mediated cell cycle arrest was associated with HDAC inhibitor-mediated induction of CDK inhibitor expression. In MCF-7 cells, IN-2001 significantly increased $p21^{WAF1}$ expression. Conclusions: In summary, cyclin-dependent kinase (CDK) induced growth inhibition, possibly through modulation of cell cycle and apoptosis regulatory proteins, such as CDK inhibitors, and cyclins. Taken together, these results provide an insight into the utility of HDAC inhibitors as a novel chemotherapeutic regime for hormone-sensitive and insensitive breast cancer.

• Journal of Life Science
• /
• v.17 no.4 s.84
• /
• pp.552-560
• /
• 2007

Histone deacetylase (HDAC) is overexpressed in a variety of cancers and is closely correlated with oncogenic factors. HDAC inhibitors such as trichostatin A(TSA) and sodium butyrate (Na-B) have been shown to induce apoptosis in vitro and in vivo in many cancer cells. The anti-apoptotic Bcl-2 protein has the remarkable ability to prevent cell death and Bcl-2 overexpression has been reported to protect against cell death. We previously reported that the apoptotic cell death of human leukemic U937 cells by TSA and Na-B treatment was associated with the down-regulation of Bcl-2 expression and activation of caspases. In the present study, we investigated the effects of Bcl-2 overexpression on the growth inhibition, cell cycle arrest and apoptosis induced by TSA and Na-B in U937 cells. TSA-induced growth inhibition, cell cycle arrest and apoptosis were significantly attenuated in Bcl-2 overexpressing U937/Bcl-2 cells however Na-B did not affected. Induction of apoptosis by TSA was accompanied by down-regulation of Bcl-2 expression, activation of caspase-3, -8 and -9, and degradation of DNA fragmentation factor/inhibitor of caspase-activated DNase, which was blocked by the overexpression of Bcl-2. Collectively, these findings suggest that ectopic expression of Bcl-2 appeared to inhibit TSA-induced apoptosis by interfering with inhibition of Bcl-2 and caspase activation.

• BMB Reports
• /
• v.36 no.1
• /
• pp.110-119
• /
• 2003

The acetylation state of histone is reversibly regulated by histone acetyltransferase (HAT) and deacetylase (HDAC). An imbalance of this reaction leads to an aberrant behavior of the cells in morphology, cell cycle, differentiation, and carcinogenesis. Recently, these key enzymes in the gene expression were cloned. They revealed a broad use of this modification, not only in histone, but also other proteins that involved transcription, nuclear transport, and cytoskeleton. These results suggest that HAT/HDAC takes charge of multiple-functions in the cell, not just the gene expression. HDAC is especially known to play an important role in carcinogenesis. The enzyme has been considered a target molecule for cancer therapy. The inhibition of HDAC activity by a specific inhibitor induces growth arrest, differentiation, and apoptosis of transformed or several cancer cells. Some of these inhibitors are in a clinical trial at phase I or phase II. The discovery and development of specific HDAC inhibitors are helpful for cancer therapy, and decipher the molecular mode of action for HDAC.