姜黄素抑制Raji细胞组蛋白去乙酰化酶活性阻止细胞周期进程

目的:研究姜黄素对Raji细胞组蛋白去乙酰化酶(HDAC1)的抑制作用及细胞周期蛋白p21WAFt/CIP1的表达情况,探讨姜黄素抗淋巴瘤的机制.方法:培养人B细胞淋巴瘤细胞株Raji,应用姜黄素在不同浓度和时间点处理细胞,提取细胞的总蛋白和RNA,用Western blot印迹技术检测HDAC1和p21WAF1/CIP1蛋白的表达,并用RT-PCR技术检测p2WAF1/CIP1 mRNA的水平,用流式细胞仪分析细胞周期.结果:(1)姜黄素明显抑制HDAC1的表达,在4 h开始下降,持续48 h,呈时间和浓度依赖性;(2)姜黄素明显促进p21WAF1/CIP1蛋白和p21WAF1/CIP1mRNA表达,在8 h mRNA开始上升,12 h可以检测到p21WAF1/CIP1蛋白表达升高,也呈时间和浓度依赖效应;(3)姜黄素在24 h时,明显诱导Raji细胞G0/G1期阻止.结论:姜黄素能够抑制HDAC1的表达,并对细胞周期蛋白p21WAF1/CIP1和p21WAF1/CIP1mRNA的表达有明显促进作用,阻止Raji细胞在G0/G1期.抑制HDAC1活性和促进p21WAF1/CIP1表达可能是姜黄素抗淋巴瘤的机制之一.     

TSA抑制NB4细胞去乙酰化酶活性并促进细胞周期素激酶抑制剂表达

目的　研究曲古菌素A(TrichostatinA,TSA)对NB4细胞组蛋白去乙酰化酶HDAC1的作用及细胞周期依赖激酶抑制剂P21WAF1 /CIP1的表达,探讨TSA抗白血病的作用机制。方法　培养人的急性早幼粒细胞白血病细胞株NB4,应用TSA在不同浓度和不同时间点处理细胞,提取细胞的总蛋白和mRNA,用Westernblot蛋白质印迹技术检测HDAC1和P21WAF1 /CIP1 蛋白表达, 并用RT PCR技术同时检测P21WAF1 /CIP1 mRNA的表达水平。结果　①TSA明显抑制HDAC1的活性和表达,在IC50浓度时作用 4hHDAC1已经降低,持续 48 h;在较低浓度 ( 37 5 nmol·L-1 )时就对HDAC1有明显的抑制作用,但在 75 ~ 300 nmol·L-1时HDAC1降低水平未见明显区别;②TSA明显促进P21WAF1 /CIP1蛋白和mRNA的表达,在 8h时mRNA已增高, 12h后可见到蛋白增加,在浓度大于 150nmol·L-1时呈明显时间和剂量依赖性。结论　TSA明显抑制HDAC1活性和表达,促进细胞周期依赖性激酶抑制剂P21WAF1 /CIP1蛋白和mRNA水平升高,有明显的抗白血病作用。抑制HDAC1活性和促进P21WAF1 /CIP1增加可能是TSA抗白血病的机制之一。     

组蛋白去乙酰化酶抑制剂调控p21~(WAF1/CIP1)启动子乙酰化水平影响乳腺癌MCF-7细胞周期

目的研究组蛋白去乙酰化酶抑制剂(histone deacetylase inhibitor,HDACI)调控p21~(WAF1/CIP1)启动子乙酰化水平,调节乳腺癌MCF-7细胞周期的分子机制。方法采用实时定量PCR、Western blot和DNA-Ch IP方法测定SAHA对乳腺癌MCF-7细胞周期调控系统的影响;应用染色质免疫沉淀(chromatin immunoprecipitation,Ch IP)技术探究SAHA调控p21~(WAF1/CIP1)启动子乙酰化水平的情况。结果 SAHA明显影响乳腺癌细胞周期相关调控因子的表达;在针对p21~(WAF1/CIP1)基因功能的筛查中发现,SAHA可明显诱导p21~(WAF1/CIP1)mRNA和蛋白的表达,并且可调节p21~(WAF1/CIP1)启动子乙酰化水平。结论 SAHA通过影响p21~(WAF1/CIP1)启动子乙酰化程度调节乳腺癌MCF-7细胞周期的进程。     

乳腺癌MCF-7细胞p21~(WAF1/CIP1)启动子区HDAC1高功能结合位点的研究

目的研究乳腺癌MCF-7细胞中组蛋白去乙酰化酶1(histone deacetylases 1,HDAC1)募集于p21~(WAF1/CIP1)启动子区调控其转录活性的特异性结合位点。方法将处于对数生长期的乳腺癌MCF-7细胞在无血清培养基中饥饿24 h后,分别用20μmol·L~(-1)0.88μL SAHA(S组)、0.625 nmol·L~(-1)10μL Leptin(L组)处理24 h,对照组(B组)细胞培养在完全型RPMI 1640培养基中。各组细胞裂解液与HDAC1抗体孵育,收集纯化结合HDAC1抗体的DNA片段,应用Realtime PCR法检测p21~(WAF1/CIP1)启动子区从TSS到其上游(+2~-4 000 bp)f1~f10片段的DNA相对表达量并用2-ΔΔCT法分析。结果 B组中,HDAC1抗体在p21~(WAF1/CIP1)启动子区f1、f8片段有高亲和力,f8片段达最高。S组中,HDAC1抗体与p21~(WAF1/CIP1)启动子区f1~f10片段结合量明显低于对照组,f8片段达最低,而在L组此片段与HDAC1抗体结合量达最大值。结论乳腺癌MCF-7细胞增殖过程中,HDAC1可被招募至p21~(WAF1/CIP1)启动子区,该启动子区上游-2 800 bp至-3 200 bp DNA片段是与HDAC1高度结合的靶功能区。     

应用丙戊酸钠调节组蛋白乙酰化修饰抑制肝癌细胞增殖的作用及机制

目的观察应用组蛋白脱乙酰酶抑制剂丙戊酸钠调节染色体组蛋白低乙酰化水平对肝癌细胞增殖的作用，并进一步检测Cyctin A、Cyclin D1、Cyclin E、P21^Waf/cip1蛋白及mRNA表达变化，探讨其分子作用机制。方法应用0．75～4．0mmol／L丙戊酸钠作用于肝癌细胞系HepG2细胞后，MTT法检测细胞生长抑制、细胞克隆形成试验观察克隆形成率、碘化丙啶标记流式细胞术检测细胞周期、间接免疫荧光法分析Cyclin A、Cyclin D1、Cyclin E、P21^Waf/cip1蛋白表达，RT—PCR检测分析Cyclin A、Cyclin D1、Cyclin E、P21^Waf/cip1 mRNA表达。结果0．75～4．0mmol／L丙戊酸钠作用24、48、72、96h，观察组出现了时间-剂量依赖趋势的生长抑制，同时细胞克隆形成率显著降低，对照组细胞增殖周期G1、S、M期所占比例未见明显改变，而观察组则随药物浓度、作用时间的不同而出现不同程度的细胞增殖周期G1期阻滞，G1期比例由55．4％～82．8％不等，差异有统计学意义（P〈0．01）。观察组Cyclin A、Cyclin D1蛋白及mRNA表达均被明显下调而P21^Waf/cip1蛋白、mRNA表达则被明显上调，与对照组比较差异均有统计学意义（均P〈0．01）；而Cyclin E蛋白和mRNA表达变化则未见明显差异（P〉0．05）。结论通过应用特异性组蛋白脱乙酰酶抑制剂调节组蛋白乙酰化修饰可明显抑制肝癌细胞生长、抑制细胞克隆形成、阻滞细胞增殖周期于G1期；丙戊酸钠作为组蛋白脱乙酰酶抑制剂可明显抑制肝癌细胞增殖，其作用机制是通过上调P21^Waf/cip1 mRNA蛋白表达，下调Cyclin D1、Cyclin A mRNA蛋白表达分别和／或协同实现。     

没药倍半萜诱导的p21WAF/CIP1蛋白参与抑制前列腺癌细胞增殖

目的 探讨没药的两个倍半萜单体化合物抑制前列腺癌细胞增殖的作用机制.方法 应用细胞增殖实验噻唑蓝(MTT)法检测化合物对人前列腺癌细胞株LNCaP的影响;流式细胞术进一步分析前列腺癌细胞经化合物处理后细胞周期时相的变化;Western blot检测化合物对细胞周期相关蛋白p21WAF/CIP1(p21)和cyclin D表达的影响;利用细胞转染技术检测化合物对cyclin D启动子表达活力的影响.结果 两个没药倍半萜单体化合物对前列腺癌细胞均有显著的抑制活力,使细胞停滞于GO/G.期;且能在蛋白水平诱导p21WAF/CIP1的表达,同时降低cyclinD的表达.结论 没药倍半萜化合物抑制前列腺癌细胞的增殖,可能是通过上调p21WAF/CIP1的表达、下调cyclinD蛋白的表达来实现的.     

曲古抑菌素A对肾癌细胞系GRC-1生长的抑制作用

目的 研究组蛋白去乙酰化酶(HDAC)抑制药曲古抑菌素A(TSA)对肾癌GRC-1细胞生长的影响及其作用机制. 方法使用TSA处理GRC-1细胞. 噻唑蓝(MTT)法检测细胞生长;流式细胞仪分析细胞凋亡及细胞周期;Western blot免疫印迹分析p53,p21和bcl-2表达. 结果 TSA能明显抑制GRC-1细胞的增殖,且具有明显的剂量依赖性;TSA处理72 h的GRC-1细胞早期凋亡率明显提高,G0/G1期细胞比例显著升高,S期细胞比例显著降低. TSA能够明显下调bcl-2的表达,上调p21的表达,而对p53的没有显著影响. 结论TSA可以通过诱导肾肿瘤细胞的凋亡和周期阻滞而抑制癌细胞生长;其发生机制可能与下调抗凋亡基因bcl-2和上调肿瘤抑制基因p21的表达有关,TSA可能依赖非p53途径调控p21的表达.     

组蛋白去乙酰酶抑制剂的研究进展

组蛋白乙酰转移酶(histone acetyltransferase,HAT)和组蛋白去乙酰酶(histone deacetylase,HDAC)通过对组蛋白氮端氨基酸残基进行乙酰化或去乙酰化,调节组蛋白的乙酰化水平,调控基因表达,该过程与癌症的发生具有密切的关系.组蛋白去乙酰酶抑制剂通过增加细胞内组蛋白的乙酰化程度,提高p21等基因的表达水平等途径,抑制肿瘤细胞的增殖,诱导细胞分化和(或)凋亡.该文对HDAC抑制剂的研究进展进行系统的综述.     

曲古抑菌素A对结肠癌细胞细胞周期影响的机制研究

目的 研究组蛋白去乙酰化酶（HDAC）的抑制剂曲古抑菌素A（TSA）对结肠癌细胞株SW480细胞周期、凋亡的影响,初步探讨TSA作用细胞周期的可能机制,为HDAC抑制剂用于结肠癌治疗提供理论依据.方法 培养人结肠癌细胞系SW480,采用HDAC抑制刺TSA干预细胞,运用流式细胞术检测细胞周期、凋亡以及细胞周期素的变化,最后采用Western blot对细胞周期相关的基因进行检测.结果 TSA处理细胞后,流式细胞计数分析显示,TSA能够延缓细胞周期G1-S进程,阻滞细胞于G1期,并且影响细胞周期素cyelinE、cyclinA聚集,而对凋亡无明显的影响.Western blot显示,TSA能够上调p21wafl/Cipl、p27Kipl的表达,下调CDK2、cyclinE以及cyclinA的表达.结论 在结肠癌细胞中,TSA能够通过上调p21Wafl/Cip1、p27Kip1的表达以及下调CDK2、cyclinE、cyclinA的表达,从而阻滞细胞周期于G1期,最终影响肿瘤细胞的生长.     

Evidence of a functional role for p21WAF1/CIP1 down-regulation in synergistic antileukemic interactions between the histone deacetylase inhibitor sodium butyrate and flavopiridol

The functional significance of disruption of p21(WAF1/CIP1) induction by flavopiridol (FP) in human leukemia cells (Jurkat) exposed to the histone deacetylase (HDAC) inhibitor sodium butyrate (SB) was investigated. Coexposure of leukemic cells to FP blocked SB-mediated induction of p21(WAF1/CIP1) and resulted in a marked increase in mitochondrial injury, activation of procaspases-3 and -8, Bid cleavage, and PARP degradation. Enforced expression of p21(WAF1/CIP1) (i.e., in Jurkat cells inducibly expressing p21(WAF1/CIP1) under the control of a doxycycline-responsive promoter) partially but significantly reduced cytochrome c and apoptosis-inducing factor release, loss of mitochondrial membrane potential, caspase-3 and -8 activation, Bid cleavage, poly(ADP-ribose)polymerase (PARP) degradation, and apoptosis in response to SB/FP. Furthermore, increasing expression of p21(WAF1/CIP1) (i.e., by culturing cells in the presence of higher concentrations of doxycycline) rendered cells more resistant to SB/FP-mediated lethality. Enforced expression of p21(WAF1/CIP1) did not modify SB/FP-mediated JNK activation or generation of reactive oxygen species. Consistent with these results, Jurkat cells stably expressing a p21(WAF1/CIP1) nuclear localization mutant (p21DeltaNLS) were also resistant to SB/FP-mediated mitochondrial injury, activation of procaspases-3 and -8, PARP cleavage, and apoptosis. Finally, enforced expression of full-length or ectopic expression of DeltaNLS p21(WAF1/CIP1) increased the amount of p21(WAF1/CIP1) coimmunoprecipitating with procaspase-3. Together, these findings suggest that interruption of HDAC-mediated p21(WAF1/CIP1) induction by FP plays a significant functional role in potentiating apoptosis, possibly by preventing the formation of a procaspase-3/p21(WAF1/CIP1) complex.     

Novel inhibitors of human histone deacetylases: design, synthesis, enzyme inhibition, and cancer cell growth inhibition of SAHA-based non-hydroxamates

To find novel non-hydroxamate histone deacetylase (HDAC) inhibitors, a series of compounds modeled after suberoylanilide hydroxamic acid (SAHA) was designed and synthesized. In this series, compound 7, in which the hydroxamic acid of SAHA is replaced by a thiol, was found to be as potent as SAHA, and optimization of this series led to the identification of HDAC inhibitors more potent than SAHA. In cancer cell growth inhibition assay, S-isobutyryl derivative 51 showed strong activity, and its potency was comparable to that of SAHA. The cancer cell growth inhibitory activity was verified to be the result of histone hyperacetylation and subsequent induction of p21(WAF1/CIP1) by Western blot analysis. Kinetical enzyme assay and molecular modeling suggest the thiol formed by enzymatic hydrolysis within the cell interacts with the zinc ion in the active site of HDACs.     

Bispyridinium dienes: histone deacetylase inhibitors with selective activities

A novel synthetic route to the cyclostellettamines 1 using as the key step a microwave-mediated macrocyclic ring-closing metathesis of precursors bispyridinium dienes 10 followed by catalytic hydrogenation has been developed. The open-chain bispyridinium dienes 10 showed uniformly higher histone deacetylase (HDAC) inhibitory potency than the natural products. Diene 10b inhibited HDAC1 and was inactive on HDAC4, whereas 10a showed a weak inhibition of HDAC1 and a higher activity on HDAC4. Neither 10b nor 10a inhibited isoforms HDAC2 and HDAC3. Cell cycle analysis, cell differentiation, and apoptosis as well as evaluation of the acetylation status of H3 lysine tails, up-regulation of p21WAF1/CIP1, and alpha-tubulin acetylation induced by the dienes 10 and cyclostellettamines 1 were also carried out on the human leukemia U937 cell line. These enzymatic and functional assays suggest that 10b is a HDAC1-selective inhibitor and 10a is a HDAC subclass IIa-selective inhibitor.     

Inhibitory effects of cancer cell proliferation by novel histone deacetylase inhibitors involve p21/WAF1 induction and G2/M arrest

Two compounds were synthesized which have a structural component other than those of our new series histone deacetylase (HDAC) inhibitors to determine the structure-activity relationship. It was also examined whether the inhibitory effects on cancer cell proliferation by HDAC inhibitors involve p21/WAF1 induction and G(1) or G(2)/M arrest in p53-mutated MG63 human osteosarcoma cells as do other HDAC inhibitors. It was demonstrated that inhibitors with the 2-naphthylcarbonyl group and hydroxamic acid at both termimal sides as well as the phenylene component at the center of molecule markedly induce the p21/WAF1 protein by stimulating p21/WAF1 gene promoter activity. Furthermore, cell cycle analysis revealed that these compounds arrest MG63 cells in the G(2)/M phase.     

Synthesis and biological properties of novel, uracil-containing histone deacetylase inhibitors

A novel series of compounds containing a uracil moiety as the connection unit between a phenyl/phenylalkyl portion and a N-hydroxy-polymethylenealkanamide or -methylenecinnamylamide group (uracil-based hydroxamic acids, UBHAs) was tested against maize histone deacetylases (HDACs) and mouse HDAC1. Compounds with a phenyl/benzyl ring at the uracil-C6 position and bearing 4-5 carbon units as well as a m- or p-methylenecinnamyl moiety as a spacer were the most potent inhibitors. In cell-based human HDAC1 and HDAC4 assays, the two UBHAs tested inhibited the HDAC1 but not HDAC4 immunoprecipitate activity. When tested in human leukemia U937 cells, some UBHAs produced G1 phase arrest of the cell cycle. Moreover, 1j showed high antiproliferative and dose-dependent granulocytic differentiation properties. The tested UBHAs displayed weak p21WAF1/CIP1 induction in U937 cells, and 1d and 1j showed high histone H3 and alpha-tubulin acetylation effects.     

SAHA and curcumin combinations co-enhance histone acetylation in human cancer cells but operate antagonistically in exerting cytotoxic effects

Suberoylanilide hydroxamic acid (1), as well as other histone deacetylase (HDAC) inhibitors, are promising, targeted anticancer agents. Curcumin (2), a possible antitumor agent, exhibits a HDAC inhibiting effect but with a different mechanism, and was proposed to synergize with other drugs, including HDAC inhibitors. The present study was undertaken to evaluate the possible inhibitory effects of 1 and 2 combinations on the growth of nine human cancer cell lines. Drug combinations resulted in an antagonistic cytotoxic effect, as characterized by the Loewe additivity model, observed in all the cell lines. On the other hand, histone hyperacetylation was synergistically or at least additively induced by 1 and 2 combinations, in four cell lines tested. Despite the enhanced histone acetylation, 1 plus 2 produced a significant antagonism in the induced activation of downstream p21^CIP/WAF1 expression. Concomitantly, induced reactive oxygen species (ROS) production was antagonistically diminished in combinations especially at low concentration of 2. We conclude that 1 and 2 exert an antagonistic cytotoxicity on a variety of cancer cell lines, and suggest that mechanisms mediating their antagonism lie at levels of p21^CIP/WAF1 expression and ROS production, rather than at histone acetylation.