Antimalarial activity of the anticancer histone deacetylase inhibitor SB939

Histone deacetylase (HDAC) enzymes posttranslationally modify lysines on histone and nonhistone proteins and play crucial roles in epigenetic regulation and other important cellular processes. HDAC inhibitors (e.g., suberoylanilide hydroxamic acid [SAHA; also known as vorinostat]) are used clinically to treat some cancers and are under investigation for use against many other diseases. Development of new HDAC inhibitors for noncancer indications has the potential to be accelerated by piggybacking onto cancer studies, as several HDAC inhibitors have undergone or are undergoing clinical trials. One such compound, SB939, is a new orally active hydroxamate-based HDAC inhibitor with an improved pharmacokinetic profile compared to that of SAHA. In this study, the in vitro and in vivo antiplasmodial activities of SB939 were investigated. SB939 was found to be a potent inhibitor of the growth of Plasmodium falciparum asexual-stage parasites in vitro (50% inhibitory concentration [IC(50)], 100 to 200 nM), causing hyperacetylation of parasite histone and nonhistone proteins. In combination with the aspartic protease inhibitor lopinavir, SB939 displayed additive activity. SB939 also potently inhibited the in vitro growth of exoerythrocytic-stage Plasmodium parasites in liver cells (IC(50), ~150 nM), suggesting that inhibitor targeting to multiple malaria parasite life cycle stages may be possible. In an experimental in vivo murine model of cerebral malaria, orally administered SB939 significantly inhibited P. berghei ANKA parasite growth, preventing development of cerebral malaria-like symptoms. These results identify SB939 as a potent new antimalarial HDAC inhibitor and underscore the potential of investigating next-generation anticancer HDAC inhibitors as prospective new drug leads for treatment of malaria.     

Potentiation of radiation-induced cell killing by histone deacetylase inhibitor

HDAC inhibitor has been focused as a molecular target agent for cancer treatment because of unique pharmacological activity. HDAC inhibitors induce cancer cells to undergo growth arrest, differentiation or induce apoptosis in vitro, and also inhibit the growth of transplanted tumors in vivo, but the enhancement effect or interaction of HDAC inhibitors with other chemotherapeutic agents or radiation has not yet been fully investigated. Biade et al examined the effect of trichostatin A (TSA), and reported synergistic enhancement of radiosensitivity in human cancer cell lines. We also confirmed the similar results in vitro by using TSA in combination with radiation. The main purpose of this paper is to review the current status of HDAC inhibitor in clinical use, and evaluate the potential possibility for the potentiation of radiation-induced cell killing including the results of our research.     

Potent in vivo antimalarial activity of water-soluble artemisinin nano-preparations

Artemisinin is a remarkable compound whose derivatives and combinations with multiple drugs have been utilized at the forefront of malaria treatment. However, the inherent issues of the parent compound such as poor bioavailability, short serum half-life, and high first-pass metabolism partially limit further applications of this drug. In this study, we enhanced the aqueous phase solubility of artemisinin by encapsulating it in two nanocarriers based on the polymer polycaprolactone (ART-PCL) and lipid-based Large Unilamellar Vesicles (ART-LIPO) respectively. Both nanoformulations exhibit in vitro parasite killing activity against Plasmodium falciparum with the ART-LIPO performing at comparable efficacy to the control drug solubilized in ethanol. These water-soluble formulations showed potent in vivo antimalarial activity as well in the mouse model of malaria at equivalent doses of the parent drug. Additionally, the artemisinin-PCL nanoformulation used in combination with either pyrimethamine or chloroquine increased the survival of the Plasmodium berghei infected mice for more than 34 days and effectively cured the mice of the infection. We highlight the potential for polymer and liposome-based nanocarriers in improving not only the aqueous phase solubility of artemisinin but also concomitantly retaining its therapeutic efficacy in vivo as well.

Polymer and liposome-based nanocarriers not only improve the aqueous phase solubility of artemisinin but also helps to retain its therapeutic efficacy in vivo as well.     

Antimalarial activity of phenylthiazolyl-bearing hydroxamate-based histone deacetylase inhibitors

The antimalarial activity and pharmacology of a series of phenylthiazolyl-bearing hydroxamate-based histone deacetylase inhibitors (HDACIs) was evaluated. In in vitro growth inhibition assays approximately 50 analogs were evaluated against four drug resistant strains of Plasmodium falciparum. The range of 50% inhibitory concentrations (IC₅₀s) was 0.0005 to >1 μM. Five analogs exhibited IC₅₀s of <3 nM, and three of these exhibited selectivity indices of >600. The most potent compound, WR301801 (YC-2-88) was shown to cause hyperacetylation of P. falciparum histones, which is a marker for HDAC inhibition in eukaryotic cells. The compound also inhibited malarial and mammalian HDAC activity in functional assays at low nanomolar concentrations. WR301801 did not exhibit cures in P. berghei-infected mice at oral doses as high as 640 mg/kg/day for 3 days or in P. falciparum-infected Aotus lemurinus lemurinus monkeys at oral doses of 32 mg/kg/day for 3 days, despite high relative bioavailability. The failure of monotherapy in mice may be due to a short half-life, since the compound was rapidly hydrolyzed to an inactive acid metabolite by loss of its hydroxamate group in vitro (half-life of 11 min in mouse microsomes) and in vivo (half-life in mice of 3.5 h after a single oral dose of 50 mg/kg). However, WR301801 exhibited cures in P. berghei-infected mice when combined at doses of 52 mg/kg/day orally with subcurative doses of chloroquine. Next-generation HDACIs with greater metabolic stability than WR301801 may be useful as antimalarials if combined appropriately with conventional antimalarial drugs.     

Experimental therapy of malignant gliomas using the inhibitor of histone deacetylase MS-275

Inhibitors of histone deacetylases are promising compounds for the treatment of cancer but have not been systematically explored in malignant brain tumors. Here, we characterize the benzamide MS-275, a class I histone deacetylase inhibitor, as potent drug for experimental therapy of glioblastomas. Treatment of four glioma cell lines (U87MG, C6, F98, and SMA-560) with MS-275 significantly reduced cell growth in a concentration-dependent manner (IC(90), 3.75 micromol/L). Its antiproliferative effect was corroborated using a bromodeoxyuridine proliferation assay and was mediated by G(0)-G(1) cell cycle arrest (i.e., up-regulation of p21/WAF) and apoptotic cell death. Implantation of enhanced green fluorescent protein-transfected F98 glioma cells into slice cultures of rat brain confirmed the cytostatic effect of MS-275 without neurotoxic damage to the organotypic neuronal environment in a dose escalation up to 20 micromol/L. A single intratumoral injection of MS-275 7 days after orthotopic implantation of glioma cells in syngeneic rats confirmed the chemotherapeutic efficacy of MS-275 in vivo. Furthermore, its propensity to pass the blood-brain barrier and to increase the protein level of acetylated histone H3 in brain tissue identifies MS-275 as a promising candidate drug in the treatment of malignant gliomas.     

组蛋白去乙酰化酶抑制剂SAHA诱导骨髓瘤细胞的凋亡

背景：SAHA是一种新型的组蛋白去乙酰化酶抑制剂,目前有关其对多发性骨髓瘤细胞作用的研究还少见报道,而且其诱导细胞凋亡的分子机制还不十分清楚。目的：观察SAHA对多发性骨髓瘤细胞株U266细胞增殖和凋亡的影响,并分析其可能机制。方法：采用锥虫蓝拒染法、四氮唑蓝比色法检测SAHA对U266细胞增殖的影响。AllllexinV和PI染色后应用流式细胞仪检测SAHA作用U266细胞的凋亡率,Hoechst33342染色法检测凋亡细胞的形态。Western-blot方法检测信号转导通路Ras/Raf/Mek/Erk相关蛋白的表达水平。结果与结论：锥虫蓝拒染法和四氮唑蓝比色法均显示,SAHA可明显抑制U266细胞增殖,且具有时间剂量依赖性。0.5,2,4μmol/L SAHA作用U266细胞48h后,经流式细胞仪检测细胞凋亡率分别为（17.61±1.30）%,（43.13±3.80）%和（74.01±4.39）%,呈剂量依赖性（P〈0.05）。Hoechst33342染色荧光显微镜下可见,SAHA组细胞胞核出现明显的核固缩、核碎裂,而对照组改变不明显。Western-blot结果显示U266细胞经SAHA处理后,Raf-1和Erk蛋白的磷酸化水平受到明显抑制,药物作用48h时出现显著降低。提示SAHA抑制多发性骨髓瘤细胞株U266细胞增殖并诱导凋亡,信号转导通路Ras/Raf/Mek/Erk阻断是机制之一。     

CRA-024781: a novel synthetic inhibitor of histone deacetylase enzymes with antitumor activity in vitro and in vivo

CRA-024781 is a novel, broad spectrum hydroxamic acid-based inhibitor of histone deacetylase (HDAC) that shows antitumor activity in vitro and in vivo preclinically and is under evaluation in phase I clinical trials for cancer. CRA-024781 inhibited pure recombinant HDAC1 with a K(i) of 0.007 mumol/L, and also inhibited the other HDAC isozymes HDAC2, HDAC3/SMRT, HDAC6, HDAC8, and HDAC10 in the nanomolar range. Treatment of cultured tumor cell lines grown in vitro with CRA-024781 resulted in the accumulation of acetylated histone and acetylated tubulin, resulting in an inhibition of tumor cell growth and the induction of apoptosis. CRA-024781 parenterally administered to mice harboring HCT116 or DLD-1 colon tumor xenografts resulted in a statistically significant reduction in tumor growth at doses that were well tolerated as measured by body weight. Inhibition of tumor growth was accompanied by an increase in the acetylation of alpha-tubulin in peripheral blood mononuclear cells, and an alteration in the expression of many genes in the tumors, including several involved in apoptosis and cell growth. These results reveal CRA-024781 to be a novel HDAC inhibitor with potent antitumor activity.     

Potent in vitro antimalarial activity of metacycloprodigiosin isolated from Streptomyces spectabilis BCC 4785

Bioassay-guided fractionation of the extract from the fermentation broth of Streptomyces spectabilis BCC 4785 led to the isolation of three principle antimalarial agents, metacycloprodigiosin, bafilomycin A(1), and spectinabilin. Metacycloprodigiosin exhibited potent in vitro activity against Plasmodium falciparum K1, with a 50% inhibitory concentration of 0.0050 +/- 0.0010 microg/ml, while its cytotoxicity was much weaker.     

Characterisation of the novel apoptotic and therapeutic activities of the histone deacetylase inhibitor romidepsin

Histone deacetylase inhibitors (HDACi) are compounds that target the epigenome and cause tumor cell-selective apoptosis. A large number of these agents that have different chemical structures and can target multiple HDACs are being testing in clinical trials and vorinostat is now an approved drug for the treatment of cutaneous T-cell lymphoma. Although these agents are showing promise for the treatment of hematologic malignancies, it is possible that different drugs may have different mechanistic, biological, and therapeutic activities. When comparing an HDACi belonging to the hydroxamic acid class of compounds (vorinostat) with a cyclic tetrapeptide (romidepsin), we showed that these agents regulate the expression of a common set of cellular genes, but certain genes specifically responded to each agent. Using the Emu-myc mouse model of B-cell lymphoma, we showed previously that overexpression of the prosurvival proteins Bcl-2 and Bcl-XL inhibited the apoptotic and therapeutic activities of the vorinostat. Herein, we compared and contrasted the apoptotic-inducing activities of the hydroxamic acid oxamflatin with romidepsin. Like vorinostat, oxamflatin was unable to kill lymphomas overexpressing Bcl-2 and Bcl-XL, indicating that these proteins can generally protect cells against this class of HDACi. In contrast, romidepsin was able to induce apoptosis in lymphomas overexpressing Bcl-2 with delayed kinetics of cell death and could mediate therapeutic responses against these lymphomas. However, romidepsin was inactive when Bcl-XL was overexpressed. These data provide strong support that HDACi of different chemical classes may have subtle yet potentially important differences in their molecular and biological activities.     

Theophylline restores histone deacetylase activity and steroid responses in COPD macrophages

Chronic obstructive pulmonary disease (COPD) is a common chronic inflammatory disease of the lungs with little or no response to glucocorticoids and a high level of oxidative stress. Histone deacetylase (HDAC) activity is reduced in cells of cigarette smokers, and low concentrations of theophylline can increase HDAC activity. We measured the effect of theophylline on HDAC activity and inflammatory gene expression in alveolar macrophages (AM) from patients with COPD. AM from normal smokers showed a decrease in HDAC activity compared with normal control subjects, and this was further reduced in COPD patients (51% decrease, P < 0.01). COPD AMs also showed increased basal release of IL-8 and TNF-alpha, which was poorly suppressed by dexamethasone. Theophylline induced a sixfold increase in HDAC activity in COPD AM lysates and significantly enhanced dexamethasone suppression of induced IL-8 release, an effect that was blocked by the HDAC inhibitor trichostatin A. Therefore, theophylline might restore steroid responsiveness in COPD patients.     

MGCD0103, a novel isotype-selective histone deacetylase inhibitor, has broad spectrum antitumor activity in vitro and in vivo

Nonselective inhibitors of human histone deacetylases (HDAC) are known to have antitumor activity in mice in vivo, and several of them are under clinical investigation. The first of these, Vorinostat (SAHA), has been approved for treatment of cutaneous T-cell lymphoma. Questions remain concerning which HDAC isotype(s) are the best to target for anticancer activity and whether increased efficacy and safety will result with an isotype-selective HDAC inhibitor. We have developed an isotype-selective HDAC inhibitor, MGCD0103, which potently targets human HDAC1 but also has inhibitory activity against HDAC2, HDAC3, and HDAC11 in vitro. In intact cells, MGCD0103 inhibited only a fraction of the total HDAC activity and showed long-lasting inhibitory activity even upon drug removal. MGCD0103 induced hyperacetylation of histones, selectively induced apoptosis, and caused cell cycle blockade in various human cancer cell lines in a dose-dependent manner. MGCD0103 exhibited potent and selective antiproliferative activities against a broad spectrum of human cancer cell lines in vitro, and HDAC inhibitory activity was required for these effects. In vivo, MGCD0103 significantly inhibited growth of human tumor xenografts in nude mice in a dose-dependent manner and the antitumor activity correlated with induction of histone acetylation in tumors. Our findings suggest that the isotype-selective HDAC inhibition by MGCD0103 is sufficient for antitumor activity in vivo and that further clinical investigation is warranted.     

KD5170, a novel mercaptoketone-based histone deacetylase inhibitor that exhibits broad spectrum antitumor activity in vitro and in vivo

Histone deacetylase (HDAC) inhibitors have garnered significant attention as cancer drugs. These therapeutic agents have recently been clinically validated with the market approval of vorinostat (SAHA, Zolinza) for treatment of cutaneous T-cell lymphoma. Like vorinostat, most of the small-molecule HDAC inhibitors in clinical development are hydroxamic acids, whose inhibitory activity stems from their ability to coordinate the catalytic Zn2+ in the active site of HDACs. We sought to identify novel, nonhydroxamate-based HDAC inhibitors with potentially distinct pharmaceutical properties via an ultra-high throughput small molecule biochemical screen against the HDAC activity in a HeLa cell nuclear extract. An alpha-mercaptoketone series was identified and chemically optimized. The lead compound, KD5170, exhibits HDAC inhibitory activity with an IC50 of 0.045 micromol/L in the screening biochemical assay and an EC50 of 0.025 micromol/L in HeLa cell-based assays that monitor histone H3 acetylation. KD5170 also exhibits broad spectrum classes I and II HDAC inhibition in assays using purified recombinant human isoforms. KD5170 shows significant antiproliferative activity against a variety of human tumor cell lines, including the NCI-60 panel. Significant tumor growth inhibition was observed after p.o. dosing in human HCT-116 (colorectal cancer), NCI-H460 (non-small cell lung carcinoma), and PC-3 (prostate cancer) s.c. xenografts in nude mice. In addition, a significant increase in antitumor activity and time to end-point occurred when KD5170 was combined with docetaxel in xenografts of the PC-3 prostate cancer cell line. The biological and pharmaceutical profile of KD5170 supports its continued preclinical and clinical development as a broad spectrum anticancer agent.     

A histone deacetylase inhibitor enhances recombinant adeno-associated virus-mediated gene expression in tumor cells.

The transduction of cancer cells using recombinant adeno-associated virus (rAAV) occurs with low efficiency, which limits its utility in cancer gene therapy. We have previously sought to enhance rAAV-mediated transduction of cancer cells by applying DNA-damaging stresses. In this study, we examined the effects of the histone deacetylase inhibitor FR901228 on tumor transduction mediated by rAAV types 2 and 5. FR901228 treatment significantly improved the expression of the transgene in four cancer cell lines. The cell surface levels of alpha v integrin, FGF-R1, and PDGF-R were modestly enhanced by the presence of FR901228. These results suggest that the superior transduction induced by the HDAC inhibitor was due to an enhancement of transgene expression rather than increased viral entry. Furthermore, we characterized the association of the acetylated histone H3 in the episomal AAV vector genome by using the chromatin immunoprecipitation assay. The results suggest that the superior transduction may be related to the proposed histone-associated chromatin form of the rAAV concatemer in transduced cells. In the analysis with subcutaneous tumor models, strong enhancement of the transgene expression as well as therapeutic effect was confirmed in vivo. The use of this HDAC inhibitor may enhance the utility of rAAV-mediated transduction strategies for cancer gene therapy.     

Lipid rafts remodeling in estrogen receptor-negative breast cancer is reversed by histone deacetylase inhibitor

Recently, we have found dramatic overexpression of ecto-5'-nucleotidase (or CD73), a glycosylphosphatidylinositol-anchored component of lipid rafts, in estrogen receptor-negative [ER-] breast cancer cell lines and in clinical samples. To find out whether there is a more general shift in expression profile of membrane proteins, we undertook an investigation on the expression of selected membrane and cytoskeletal proteins in aggressive and metastatic breast cancer cells. Our analysis revealed a remarkably uniform shift in expression of a broad range of membrane, cytoskeletal, and signaling proteins in ER- cells. A similar change was found in two in vitro models of transition to ER- breast cancer: drug-resistant Adr2 and c-Jun-transformed clones of MCF-7 cells. Interestingly, similar expression pattern was observed in normal fibroblasts, suggesting the commonality of membrane determinants of invasive cancer cells with normal mesenchymal phenotype. Because a number of investigated proteins are components of lipid rafts, our results suggest that there is a major remodeling of lipid rafts and underlying cytoskeleton in ER- breast cancer. To test whether this broadly defined ER- phenotype could be reversed by treatment with differentiating agent, we treated ER- cells with trichostatin A, an inhibitor of histone deacetylase, and observed reversal of mesenchymal and reappearance of epithelial markers. Changes in gene and protein expression also included increased capacity to generate adenosine and altered expression profile of adenosine receptors. Thus, our results suggest that during transition to invasive breast cancer there is a significant structural reorganization of lipid rafts and underlying cytoskeleton that is reversed upon histone deacetylase inhibition.     

Synergistic activity of the histone deacetylase inhibitor suberoylanilide hydroxamic acid and the bisphosphonate zoledronic acid against prostate cancer cells in vitro

Bisphosphonates are widely used agents for the treatment of malignant bone disease. They inhibit osteoclast-mediated bone resorption and can have direct effects on cancer cells. In this study, we investigated whether the anticancer activity of the third-generation bisphosphonate zoledronic acid (ZOL) could be enhanced by combination with the histone deacetylase inhibitor suberoylanilide hydroxamic acid (SAHA). We found that ZOL and SAHA cooperated to induce cell death in the prostate cancer cell lines LNCaP and PC-3. The effect was synergistic, as evidenced by combination index isobologram analysis. ZOL and SAHA synergized to induce dissipation of the mitochondrial transmembrane potential, to activate caspase-3, and to trigger DNA fragmentation, showing that the combination of ZOL and SAHA resulted in the initiation of apoptosis. Because ZOL acts by inhibiting the mevalonate pathway, thereby preventing protein prenylation, we explored whether the mevalonate pathway was also the target of the cooperative action of ZOL and SAHA. We found that geranylgeraniol, but not farnesol, significantly reduced ZOL/SAHA-induced cell death, indicating that the synergistic action of the agents was due to the inhibition of geranylgeranylation. Consistently, a direct inhibitor of geranylgeranylation, GGTI-298, synergized with SAHA to induce cell death, whereas an inhibitor of farnesylation, FTI-277, had no effect. In addition, SAHA synergized with mevastatin, an inhibitor of the proximal enzyme in the mevalonate pathway. These in vitro findings provide a rationale for an in vivo exploration into the potential of combining SAHA and ZOL, or other inhibitors of the mevalonate pathway, as an effective strategy for anticancer therapy.     

Next-generation of selective histone deacetylase inhibitors

Histone deacetylases (HDACs) are clinically validated epigenetic drug targets for cancer treatment. HDACs inhibitors (HDACis) have been successfully applied against a series of cancers. First-generation inhibitors are mainly pan-HDACis that target multiple isoforms which might lead to serious side effects. At present, the next-generation HDACis are mainly focused on being class- or isoform-selective which can provide improved risk–benefit profiles compared to non-selective inhibitors. Because of the rapid development in next-generation HDACis, it is necessary to have an updated and state-of-the-art overview. Here, we summarize the strategies and achievements of the selective HDACis.

Histone deacetylases (HDACs) are clinically validated epigenetic drug targets for cancer treatment.     

组蛋白脱乙酰酶抑制剂丙戊酸钠对胃癌细胞浸润转移的影响

目的 探讨组蛋白脱乙酰酶抑制剂丙戊酸钠对胃癌细胞侵袭、迁移能力的影响及其作用机制.方法 采用肿瘤细胞体外迁移实验和Tanswell小室侵袭模型评价丙戊酸钠对BGC-823细胞浸润转移能力的影响.同时检测BGC-823细胞中MMP-2、MMP-9的表达来探讨其作用机制.结果 对照组细胞培养24小时后迁移细胞数目较多,而丙戊酸钠试验组细胞迁移数目随药物浓度升高而逐渐减少（p〈0.001）;对照组穿过聚碳酯膜细胞数目明显高于药物实验组,差异具有显著意义（p〈0.001）;与对照组比较,试验组MMP-2、MMP-9蛋白表达被明显下调.结论 组蛋白脱乙酰酶抑制剂丙戊酸钠可显著抑制胃癌细胞侵袭转移,通过调节染色体组蛋白乙酰化水平下调金属基质蛋白酶（MMP-2、MMP-9）表达可能是其发挥作用的主要机制之一.     

Evaluation of histone deacetylase inhibitor substituted zinc and indium phthalocyanines for chemo- and photodynamic therapy

In this study, we synthesized and characterized 3-hydroxypyridin-2-thione (3-HPT) bearing zinc (ZnPc-1 and ZnPc-2) and indium (InPc-1 and InPc-2) phthalocyanine (Pc) derivatives, either non-peripherally or peripherally substituted as photosensitizer (PS) agents and evaluated their anti-cancer efficacy on two breast cancer cell lines, MDA-MB-231 and MCF-7 as well as a human endothelial cell line, HUVEC. Our results indicated different localization patterns between ZnPcs and InPcs in addition to enhanced effects on the mitochondrial network for InPcs. Moreover, peripheral or non-peripheral substitution of HDACi moieties altered cellular localization between ZnPc-1 and ZnPc-2, leading to increased IC₅₀ values along with decreased anti-cancer activity for non-peripheral substitution. When considering the compounds'' differential effects in vitro, our data indicates that further research is required to determine the ideal Pcs for anti-cancer PDT treatments since the core metals of the compounds have affected the cellular localization, and positioning of the chemotherapeutic residues may inhibit cellular penetrance.

3-Hydroxypyridin-2-thione bearing zinc and indium phthalocyanine derivatives, as photosensitizer agents have been synthesized and evaluated for their anti-cancer efficacy on two breast cancer cell lines, MDA-MB-231 and MCF-7 as well as a human endothelial cell line, HUVEC.     

组蛋白去乙酰化酶抑制剂对内毒素所致血管内皮细胞损伤的影响

目的 探讨组蛋白去乙酰化酶(HDAC)抑制剂(HDACI)对内毒素所致血管内皮细胞损伤的影响,为临床脓毒症相关血管内皮细胞损伤后的保护提供实验依据.方法 体外培养血管内皮细胞特性的EAhy926细胞株.采用四甲基偶氮唑盐(MTT)比色法检测不同剂量脂多糖(LPS,50、100、500、1 000 ng/ml)对血管内皮细胞的增殖作用.选择细胞存活率较高的LPS剂量,加入100 μ g/ml HDACI曲古抑霉素(TSA),采用蛋白质免疫印迹法(Western blotting)检测LPS刺激内皮细胞3、6、9、12、24 h时细胞内Toll样受体4(TLR4)和HDAC2的蛋白表达.结果 与空白对照组比较,100 ng/ml LPS刺激内皮细胞9、12、24 h后,TLR4蛋白表达明显上调(1.01±0.14、1.25±0.16、1.20±0.19比0.34±0.05,均P＜0.01);刺激12h、24h时HDAC2蛋白表达有所上调(1.14±0.10、1.20±0.04比0.17±0.02,均P＜0.01).与LPS组相比,TSA组刺激12 h时TLR4蛋白表达明显下调(0.37±0.07比1.25±0.16,P＜0.05),24 h时TLR4蛋白表达无明显差异(0.37土0.10比1.20±0.19,P＞0.05);TSA组各时间点HDAC2蛋白表达下调,未见条带显现.结论 LPS刺激血管内皮细胞后可上调内皮细胞TLR4及HDAC2的蛋白表达;而TSA可以下调LPS刺激内皮细胞后的TLR4表达.