Expression Of Acetylated Histone H3 Research Articles

Occlusal disharmony promotes anxiety-like behaviours by suppressing Sirt1.

Previous studies have indicated that occlusal disharmony (OD) can promote anxiety-like behaviours. However, the specific molecules involved in the development of anxiety-like behaviours and their underlying mechanisms remain unknown. OD was produced by anterior crossbite of female mice. We measured the anxiety levels of mice in each group and screened the hippocampal mRNA expression profiles of mice in the control group and OD group. The role of target mRNA in OD-induced anxiety-like behaviours was evaluated and we preliminarily explored the possible downstream pathways. The results suggested that OD can induce and promote anxiety-like behaviours with/without chronic unpredictable mild stress. We found that Sirt1 was significantly downregulated within the hippocampus in OD mice. In addition, the downregulation of Sirt1 within the hippocampus in OD and control mice promoted anxiety-like behaviours, increased acetylated histone H3 expression and decreased Dnah12 transcription levels. In contrast, in OD mice subjected to an injection of resveratrol, there was a remission of anxiety-like behaviours and an upregulation of Sirt1 in the hippocampus, the effects of which were accompanied by decreased acetylated histone H3 expression and increased Dnah12 transcription levels. OD leads to increased sensitivity to chronic stress in mice, resulting in anxiety-like behaviours. During this process, Sirt1 acts as an effective factor in the regulation of OD-induced anxiety-like behaviours. OD, as a stressor, could induce anxiety-like behaviours. It investigates the impact of OD (a stressor) on the molecular genetic of the pathophysiology of major neuropsychiatric disorders.

Raddeanin A augments the cytotoxicity of natural killer cells against chronic myeloid leukaemia cells by modulating MAPK and Ras/Raf signalling pathways.

Natural killer (NK) cell therapy, a developing approach in cancer immunotherapy, involves isolating NK cells from peripheral blood. However, due to their limited number and activity, it is essential to significantly expand these primary NK cells and enhance their cytotoxicity. In this study, we investigated how Raddeanin A potentiate NK activity using KHYG-1 cells. The results indicated that Raddeanin A increased the expression levels of cytolytic molecules such as perforin, granzymes A and granzymes B, granulysin and FasL in KHYG-1 cells. Raddeanin A treatment increased CREB phosphorylation, p65 phosphorylation, NFAT1 and acetyl-histone H3 expression. Raddeanin A elevated caspase 3 and PARP cleavage, increased t-Bid expression, promoting apoptosis in K562 cells. Furthermore, it reduced the expression of HMGB2, SET and Ape1, impairing the DNA repair process and causing K562 cells to die caspase-independently. Additionally, Raddeanin A increased ERK, p38 and JNK phosphorylation at the molecular level, which increased granzyme B production in KHYG-1 cells. Raddeanin A treatment increased Ras, Raf phosphorylation, MEK phosphorylation, NKG2D, NKp44 and NKp30 expression in KHYG-1 cells. Collectively, our data indicate that Raddeanin A enhances the cytotoxic activity of NK cells against different cancer cells.

A novel HDAC inhibitor chidamide combined with imatinib synergistically targets tyrosine kinase inhibitor resistant chronic myeloid leukemia cells

Chidamide is a novel selective histone deacetylase inhibitor (HDACi) with promising activity in hematological malignancies, but its role in chronic myeloid leukemia (CML) was marginally addressed. In this study, we firstly demonstrated that chidamide alone inhibited CML cells proliferation, induced apoptosis and cell cycle arrest. Further, chidamide combined with imatinib (IM) induced synergistic lethality in CML cell line KBM5, as well as IM-resistant CML cells KBM5T315I, associated with a marked reduction of Bcr-Abl kinase activity and acetyl-histone H3 expression. The combination treatment markedly inhibited constitutive activity of β-catenin signaling in IM-resistant cells and abolished the protective effects of mesenchymal stromal cells (MSCs) to CML cells. In addition, the co-treatment significantly reduced Bcr-Abl and β-catenin transcript levels and induced apoptosis of primary CD34+ stem/progenitor cells derived from blast crisis (BC)-CML patients, but exhibited minimal toxicity to normal CD34+ progenitors. Collectively, our data show that combination of chidamide and imatinib synergistically targets tyrosine kinase inhibitor (TKI) -resistant BC-CML cells via inhibition of Bcr-Abl and β-catenin signaling, suggesting that this combination has the potential for treating TKI-resistant CML and improving clinical outcomes of BC-CML patients.

Class I histone deacetylase (HDAC) inhibitor CI-994 promotes functional recovery following spinal cord injury

Spinal cord injury (SCI) induces severe and long-lasting neurological disability. Accumulating evidence has suggested that histone deacetylase (HDAC) inhibitors exert neuroprotective effects against various insults and deficits in the central nervous system. In the present study, we assessed the effect of the class I HDAC inhibitor CI-994 in a mouse model of SCI. Following SCI, mice were treated with either dimethyl sulfoxide (control vehicle) or 1, 10, or 30 mg/kg CI-994. Level of acetylated histone H3 expression was increased in the motor cortex and spinal cord of 10 mg/kg CCI-994-treated mice after SCI. CI-994 increased histone H3 acetylation in the myeloperoxidase-positive neutrophils and CD68-positive microglia/macrophages in the spinal cord. Although it did not appear to contribute to corticospinal tract axonal reorganization, intraperitoneal injection of CI-994 promoted behavioral recovery following SCI. Furthermore, administration of CI-994 suppressed neutrophil accumulation, inflammatory cytokine expressions, and neuronal loss as early as 3 days following injury. Thus, our findings indicate that HDAC inhibitors may improve functional recovery following SCI, especially during the early stages of the disease.

Role of spinal histone acetylation in persistent postoperative pain in rats

Objective To evaluate the role of spinal histone acetylation in persistent postoperative pain in rats. Methods Pathogen-free healthy male Sprague-Dawley rats, weighing 200-250 g, aged 2 months, in which intrathecal catheters were implanted at the lumbar level according to an improved method, were used in the study.Eighty-four rats, in which intrathecal catheters were successfully implanted, were divided into Ⅰ-Ⅵ groups(n=14 each)using a random number table.Artificial cerebrospinal fluid 20 μl was intrathecally administered at 1, 2, 3 and 4 days before operation and 1 day after operation inⅠand Ⅳ groups.At 1, 2, 3 and 4 days before operation and 1 day after operation, dimethyl sulfoxide 10 μl and SAHA(50 μg/10μl)were intrathecally injected in Ⅱ and Ⅴ groups and in Ⅲ andⅥ groups, respectively, followed by artificial cerebrospinal fluid(10 μl)flush after each injection.Rats underwent sham operation inⅠ-Ⅲ groups.Persistent postoperative pain was evoked by skin/muscle incision and traction in Ⅳ-Ⅵ groups.The mechanical paw withdrawal threshold(MWT)was measured at 1 day before operation(T0)and 1, 3, 7, 14 and 21 days after operation(T1-5). Four rats were sacrificed in each group after measurement of MWT at T4, and the lumbar segments(L4-6)of the spinal cord were removed for determination of the expression of acetylated histone H3(Ac-H3)and Ac-H4 by Western blot. Results There was no significant difference in each index amongⅠ-Ⅲ groups(P>0.05). Compared with group Ⅰ, the MWT was significantly decreased at T2-5, and the expression of Ac-H3 and Ac-H4 was down-regulated at T4 in group Ⅳ(P<0.05). Compared with group Ⅳ, the MWT was significantly increased at T2-5, and the expression of Ac-H3 and Ac-H4 was up-regulated at T4 in group Ⅵ(P<0.05). Conclusion Histone acetylation is involved in the development and maintenance of persistent postoperative pain in rats. Key words: Histones; Acetylation; Pain, postoperative; Spinal cord

Histone acetylation of oligodendrocytes protects against white matter injury induced by inflammation and hypoxia-ischemia through activation of BDNF-TrkB signaling pathway in neonatal rats

The major pathological damage in encephalopathy of prematurity is white matter injury (WMI). Perinatal hypoxic-ischemia (HI) and inflammation are two major risk factors in the development of WMI. To study the cellular and molecular mechanisms of WMI, we set up a WMI model using lipopolysaccharide-sensitized HI injury in 2-day postnatal rats. Immunofluorescence staining was used to measure the expression of acetylated histone H3 (AH3) in oligodendrocytes, the target cells of WMI; the oligodendrocyte protein markers, NG2, O4, MBP, PLP, and MAG, were detected at different developmental stages. 5-bromo-2′-deoxyuridine (BrdU) was used to detect the proliferation of oligodendrocytes. We found that the expression of AH3 was markedly decreased in oligodendrocytes at 7 days after WMI. The differentiation and maturation of oligodendrocytes were inhibited in the WMI group. After inducing histone acetylation in oligodendrocytes by treatment with sodium butyrate, the inhibition of differentiation and maturation of oligodendrocytes was reversed. Furthermore, we found that these protective effects of histone acetylation were associated with the upregulation of brain-derived neurotrophic factor (BDNF) and its receptor, tyrosine kinase B (TrkB). In conclusion, histone acetylation protects oligodendrocytes from WMI through activation of the BDNF-TrkB signaling pathway in immature brains.

Changes in acetylation of histone in spinal dorsal horn in a rat model of persistent postoperative pain

Objective To investigate the changes in acetylation of histone in the spinal dorsal horn in a rat model of persistent postoperative pain. Methods Ninety-six male Sprague-Dawley rats, weighing 200-250 g, aged 6-8 weeks, were randomly divided into 2 groups (n=48 each) using a random number table: sham operation group (group S) and persistent postoperative pain group (group PPP). The rat model of persistent postoperative pain evoked by skin/muscle incision and retraction was established according to the method described by Flatters.After the rats were anesthetized with intraperitoneal chloral hydrate, the skin and superficial muscle of the medial thigh were incised and retractors inserted.This tissue was retracted for 1 h. The mechanical paw withdrawal threshold (MWT) was measured at 1 day before operation and 1, 3, 7, 14, and 21 days after operation.Four animals were sacrificed in each group after measurement of MWT at each time point for detection of acetylated histone H3 (Ac-H3) and acetylated histone H4 (Ac-H4) expression (by Western blot analysis) and the number of Ac-H3 and Ac-H4 positive cells in the spinal cord horn (by immunofluorescence histochemistry). Results Compared with group S, the MWT was significantly decreased at 3, 7, 14 and 21 days after operation, the expression of Ac-H3 and Ac-H4b was significantly down-regulated at 3, 7 and 14 days after operation, and the number of Ac-H3 and Ac-H4 positive cells was significantly decreased at 7, 14 and 21 days after operation in group PPP (P<0.05 or 0.01). The MWT, expression of Ac-H3 and Ac-H4b, and the number of Ac-H3 and Ac-H4 positive cells were significantly higher at 21 days after operation than at 14 days after operation in group PPP (P<0.05). Conclusion Acetylation of histone in the spinal dorsal horn is decreased after operation, which may be involved in the development and maintenance of persistent postoperative pain in rats. Key words: Histones; Acetylation; Pain, postoperative; Spinal cord

Resveratrol attenuates morphine antinociceptive tolerance via SIRT1 regulation in the rat spinal cord

In recent years, researchers have begun to pay more attention to the role of Sirtuin 1 (SIRT1, a class III histone deacetylase) in pain. However, little research has been conducted examining the involvement of SIRT1 in chronic morphine tolerance. The aim of this study was to investigate the role of spinal SIRT1 and acetyl-histone H3(Ac-H3) in chronic morphine tolerance in rats. Chronic morphine tolerance was induced by twice-daily intrathecal (i.t.) injections of morphine (10μg) for 6 days. Control rats received normal saline (NS). Resveratrol (Res, a SIRT1 stimulant, 30μg i.t.) or dimethyl sulfoxide (DMSO, 10μl i.t.) was then injected on days 7–13. The thermal paw withdrawal threshold was assessed to determine the analgesic effects of morphine (10μg). qRT-PCR, western blotting and immunohistochemistry were used to detect the expression of SIRT1 and global Ac-H3. Administration of morphine for 6 days induced a stabilized antinociceptive tolerance, down-regulated SIRT1 expression and up-regulated Ac-H3 expression in the spinal dorsal horn. Resveratrol treatment from day 7 to 13 increased SIRT1 expression, suppressed global Ac-H3 expression compared to the morphine tolerance (MT) group, and significantly reversed morphine antinociceptive tolerance. These results suggest that resveratrol reversed morphine tolerance by upregulating the expression of SIRT1 in the spinal dorsal horn. SIRT1 and global Ac-H3 in the spinal cord may play an important role in the mechanisms of chronic morphine tolerance.

Changes in expression of Ac-H3 and SIRT1 in dorsal root ganglions in a rat model of negative phenotype neuropathic pain

Objective To evaluate the changes in the expression of acetylated histone H3 (Ac-H3) and deacetylase silent information regulator 1 (SIRT1) in dorsal root ganglions in a rat model of negative phenotype neuropathic pain.Methods Forty-eight male Sprague-Dawley rats,weighing 250-300 g,were randomly divided into 2 groups (n =24 each):sham operation group (group S) and C-fiber dysfunction group (group CFD).The rats were anesthetized with 10％ chloral hydrate 3 ml/kg.C-fiber dysfunction was induced by exposing sciatic nerve to 8％ capsaicin for 30 min in group CFD.The thermal withdrawal latency (TWL) and mechanical withdrawal threshold (MWT) were measured before and on 1,3,7 and 14 days after CFD.Six rats were then sacrificed at each time and the lumbar segments (L5) of the dorsal root ganglions were removed for detection of SIRT1 mRNA expression (by RT-PCR) and Ac-H3 and SIRT1 protein expression (by Western blot).Results Compared with group S,TWL was significantly increased at 1,3,7 and 14 days after CFD,SIRT1 mRNA and protein expression was up-regulated and Ac-H3 expression was down-regulated at 3,7 and 14 days after CFD (P ＜ 0.05),while no significant change was found in MWT at each time point in group CFD (P ＞ 0.05).Conclusion The mechanism of negative phenotype neuropathic pain is related to up-regulation of deacetylase SIRT1 expression and decreased acetylation of histone H3 in rat dorsal root ganglions. Key words: Neuralgia; Histones; Acetylation; Sirtuins; Ganglia, spinal

Inhibitory effect of valproic acid on bladder cancer in combination with chemotherapeutic agents in vitro and in vivo

Histone deacetylase inhibitors (HDACIs) are a promising class of drugs that act as antiproliferative agents by promoting differentiation and inducing apoptosis. Valproic acid (VPA) is an HDACI that has been widely used as an anti-convulsant and shows promise as a chemotherapeutic drug for a number of tumor cells. The present study aimed to investigate the inhibitory effect of VPA on the viability of bladder cancer cells and its synergistic effect with chemotherapeutic agents in vitro and in vivo. The cell viability of human bladder cancer cell lines following treatment with VPA and/or VPA in combination with mitomycin C, cisplatin (DDP) and adriamycin were determined using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Hoechst staining was used to observe the morphology of the apoptotic cells. Survivin protein and acetylated histone H3 levels were quantified using western blot analysis. The in vivo tumor growth inhibition of VPA was determined in rats with N-methyl-N-nitrosourea-induced bladder cancer. VPA significantly inhibited the growth of the bladder cancer cells in a concentration- and time-dependent manner. Furthermore, improved results were achieved for tumor inhibition when VPA was combined with chemotherapeutic agents in vitro and in vivo. Survivin expression decreased and acetylated histone H3 expression increased in the bladder cancer cells following the treatment with VPA. Intravesical injections of VPA were able to inhibit tumor progression when combined with DDP. In conclusion, VPA acts as an HDACI that has a direct anticancer effect and markedly enhances the action of several chemotherapy agents. VPA may sensitize bladder cancer to anticancer drugs by downregulating survivin expression.

Intravesical Treatment with Vorinostat Can Prevent Tumor Progression in MNU Induced Bladder Cancer

Background: Histone deacetylase inhibitors (HDACI) are promising class of drugs acting as antiproliferative agents by promoting differentiation as well as inducing apoptosis. Vorinostat (suberoylanilide hydroxamic acid, SAHA) is the first among this new class of anticancer drugs to be approved by FDA for the treatment of cancer but only for cutaneous T cell lymphoma (CTCL). The objective of this study is to investigate the inhibitory effect of SAHA on the viability of human bladder cancer cells and its synergetic effect with chemotherapy agents in vitro and in vivo. Methods: The cell viability of human bladder cancer cell lines after treated with SAHA or SAHA combining mitomycin c (MMC), Cisplatin (DDP) and Adriamycin (ADM) were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Hoechst staining was used to observe cell morphology for apoptotic cells. The survivin protein and acetylated histone H3 levels in bladder cancer were quantified by Western blot analysis. In vivo tumor growth inhibition of intravesical inject SAHA was determined in rats with N-methyl-N-nitrosourea (MNU) induced bladder cancer. Results: SAHA significantly inhibited growth of bladder cancer cell lines with concentration and time dependent manner. Furthermore, better results of tumor inhibition would be achieved when it was combined with chemotherapeutic agents in vitro and in vivo. Survivin expression decreased and acetylated histone H3 expression increased in bladder cancer cells lines after SAHA treatment. Intravesically injections of SAHA can inhibit tumor progress when combined with DDP. Conclusions: SAHA can act as HDACI which has direct anti-cancer effect and can enhance the action of several chemotherapy agents markedly. SAHA may sensitize bladder cancer to anti cancer drugs by down regulating survivin expression. Intravesically injections of SAHA can prevent tumor progression in MNU induced bladder cancer.

α2-Adrenoceptor agonist dexmedetomidine protects septic acute kidney injury through increasing BMP-7 and inhibiting HDAC2 and HDAC5

Bone morphogenetic protein (BMP)-7 protects sepsis-induced acute kidney injury (AKI). Dexmedetomidine (DEX), an α(2)-adrenoceptor (α(2)-AR) agonist, has anti-inflammatory effects. We investigated the protective effects of DEX on sepsis-induced AKI and the expression of BMP-7 and histone deacetylases (HDACs). In vitro, the effects of DEX or trichostatin A (TSA, an HDAC inhibitor) on TNF-α, monocyte chemotactic protein (MCP-1), BMP-7, and HDAC mRNA expression in LPS-stimulated rat renal tubular epithelial NRK52E cells, was determined using real-time PCR. In vivo, mice were intraperitoneally injected with DEX (25 μg/kg) or saline immediately and 12 h after cecal ligation and puncture (CLP) surgery. Twenty-four hours after CLP, we examined kidney injury and renal TNF-α, MCP-1, BMP-7, and HDAC expression. Survival was monitored for 120 h. LPS increased HDAC2, HDAC5, TNF-α, and MCP-1 expression, but decreased BMP-7 expression in NRK52E cells. DEX treatment decreased the HDAC2, HDAC5, TNF-α, and MCP-1 expression, but increased BMP-7 and acetyl histone H3 expression, whose effects were blocked by yohimbine, an α(2)-AR antagonist. With DEX treatment, the LPS-induced TNF-α expression and cell death were attenuated in scRNAi-NRK52E but not BMP-7 RNAi-NRK52E cells. In CLP mice, DEX treatment increased survival and attenuated AKI. The expression of HDAC2, HDAC5, TNF-α, and MCP-1 mRNA in the kidneys of CLP mice was increased, but BMP-7 was decreased. However, DEX treatment reduced those changes. DEX reduces sepsis-induced AKI by decreasing TNF-α and MCP-1 and increasing BMP-7, which is associated with decreasing HDAC2 and HDAC5, as well as increasing acetyl histone H3.

Valproate induces epigenetic modifications in lymphomonocytes from epileptic patients

Valproate (VPA) is an anti-epileptic and mood-stabilizing drug with a broad range of action and which mechanism of action still remains in part elusive. Recently the discovery that VPA modifies the epigenome increasing the transcriptional rate of target genes raises the issue of understanding the exact role of this mechanism. In this work we tested the possibility that VPA could modify the epigenome of lymphomonocytes (PBMC) obtained from epileptic patients chronically treated in monotherapy with VPA and phenobarbital. Acetyl-histone H3 expression was assessed by western blotting and global DNA methylation by incorporation of [³H]dCTP. A significant increase in histone acetylation and a correlated decrease of global DNA methylation were shown at VPA therapeutically relevant plasma concentrations. This effect was drug-related, since it was not demonstrated in PBMC obtained from phenobarbital-treated patients. Moreover, a VPA dose-response curve was performed on PBMC obtained from healthy controls, demonstrating an increase of acetyl-histone H3 content. We suggest that the epigenetic properties of VPA expressed on PBMC at these concentrations might be operative in different tissues, with possible implications for the field of neuropsychiatric disorders.

Panobinostat (LBH589)-induced acetylation of tubulin impairs megakaryocyte maturation and platelet formation

Drug-induced thrombocytopenia often results from dysregulation of normal megakaryocytopoiesis. In this study, we investigated the mechanisms responsible for thrombocytopenia associated with the use of Panobinostat (LBH589), a histone deacetylase inhibitor with promising anti-cancer activities. The effects of LBH589 were tested on the cellular and molecular aspects of megakaryocytopoiesis by utilizing an ex vivo system in which mature megakaryocytes (MK) and platelets were generated from human primary CD34(+) cells. We demonstrated that LBH589 did not affect MK proliferation or lineage commitment but inhibited MK maturation and platelet formation. Although LBH589 treatment of primary MK resulted in hyperacetylation of histones, it did not interfere with the expression of genes that play important roles during megakaryocytopoiesis. Instead, we found that LBH589 induced post-translational modifications of tubulin, a nonhistone protein that is the major component of the microtubule cytoskeleton. We then demonstrated that LBH589 treatment induced hyperacetylation of tubulin and alteration of microtubule dynamics and organization required for proper MK maturation and platelet formation. This study provides new insights into the mechanisms underlying LBH589-induced thrombocytopenia and provides a rationale for using tubulin as a target for selective histone deacetylase inhibitor therapies to treat thrombocytosis in patients with myeloproliferative neoplasms.

Ttiotropium increases cytosolic muscarinic M3 receptors and acetylated H3 histone proteins in induced sputum cells of COPD patients

ObjectiveChronic obstructive pulmonary disease (COPD) is characterized by irreversible progressive airflow limitation related to tobacco smoking. This limitation is caused by chronic inflammation of the airways and lung parenchyma and is associated with increased activity of parasympathetic system. The most effective bronchodilators in COPD are muscarinic receptor antagonists (MRA), which reverse, at least in part, compromised respiratory function. MRA also contribute to control inflammatory processes via interactions with inflammatory signaling molecules. The use of the long-acting cholinolytic bronchodilatator - tiotropium, with high affinity to M3 receptors, is suggested as a first line maintenance treatment in COPD patients.Materials and methodsIn this study we assessed M3 receptor protein expression in induced sputum of 27 stable COPD patients before and after therapy consisting of 18 μg once daily tiotropium for 12 weeks. Lung function tests including spirometry, lung volumes, and DLCO were performed before and after therapy in all COPD patients. The patients were subjected to the sputum induction procedures before and after therapy. Sputum cells were isolated, sample-specific cell profiles were characterized, and the cells were processed to isolate pure cytosolic fractions. Cytosolic M3 protein and HDAC2 levels and nuclear acetylated histone H3 (AcH3) expression was quantified using specific antibodies against human proteins and Western blot with enhanced luminescence detection.ResultsTherapy significantly increased the mean forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) volume (P < 0.05). The mean expression of M3 protein was higher by 37% after therapy (P < 0.05), HDAC2 expression was not altered, while AcH3 level was increased by about 90% (P < 0.01), compared with the corresponding data before therapy. HDAC2 expression before therapy was positively correlated with AcH3 expression (r = 0.74), while after therapy no correlation was detected. FEV1, FCV, and cytosolic M3 protein expression did not correlate with other biochemical parameters tested.ConclusionsTwelve weeks of tiotropium therapy in COPD patients improves clinical indices of lung function and involves alterations in sputum cell chromatin acetylation and also increased cholinergic M3 receptor internalization.

Decreased Acetylation of Histone H3 in Renal Cell Carcinoma: A Potential Target of Histone Deacetylase Inhibitors

Recent studies suggest that alterations in chromatin structure by histone acetylation may have an important role in the neoplastic process. We evaluated histone H3 acetylation in renal cell carcinoma and the effects of a histone deacetylase inhibitor on renal cancer cell lines. The expression of acetylated histone H3 (Lys9) in renal cell carcinoma and corresponding nonneoplastic tissue specimens was evaluated. We next assessed immunohistologically the relationships between acetylated histone H3 expression and clinicopathological parameters in 44 cases of renal cell carcinoma. Furthermore, we evaluated the effects of the histone deacetylase inhibitor depsipeptide on the renal cancer cell lines Caki-1, ACHN, 769P and 786O (ATCC). Acetylated histone H3 expression was decreased in 85.0% of renal cell carcinomas compared to levels in nonneoplastic tissue. Decreased expression was related to high nuclear tumor grade and advanced pathological tumor stage (p = 0.048 and 0.032, respectively). Depsipeptide inhibited cell line proliferation in a time and dose dependent manner. Depsipeptide induced apoptosis in Caki-1, ACHN and 786O, and induced G2 cell cycle arrest in 769P. Concomitantly depsipeptide increased acetylated histone H3 and p21(WAF/CIP1) expression, and induced Bcl-2 phosphorylation. These results suggest that the decreased acetylation of histone H3 is a common alteration in a malignant phenotype of renal cell carcinoma. Increasing the amount of acetylated histone H3 might be a therapeutic option for renal cell carcinoma.