Inhibition of autophagy significantly enhances combination therapy with sorafenib and HDAC inhibitors for human hepatoma cells

AIM:To clarify whether histone deacetylase inhibitors histone deacetylase inhibitors(HDACIs)can sensitize hepatocellular carcinoma(HCC)cells to sorafenib treatment.METHODS:Bax,Bcl-2,ATG5-ATG12,p21,and p27protein levels in Hep3B,HepG2,and PLC/PRF/5 cells were examined by Western blot.CCK8 and a fluorometric caspase-3 assay were used to examine cellular viability and apoptosis levels.The effect of Beclin-1 on sensitization of HCC cells to sorafenib was examined by transfecting Beclin-1 siRNA into Hep3B,HepG2,and PLC/PRF/5 cells.RESULTS:Autophagy inhibition enhances the inhibitory effects of vorinostat and sorafenib alone or in combination on HCC cell growth.Vorinostat and sorafenib synergistically induced apoptosis and cell cycle alterations.Western blot data indicated that HDACIs and Beclin-1 knockdown increased the p53 acetylation level.The knockdown of Beclin-1 enhanced the synergistic effect of the combination of vorinostat with sorafenib.CONCLUSION:HDACIs can sensitize HCC cells to sorafenib treatment by regulating the acetylation level of Beclin-1.     

组蛋白修饰与肝癌关系的研究进展

组蛋白修饰模式的异常能导致基因表达的改变,这在肝癌的发生、发展中起重要作用。组蛋白修饰酶相关抑制剂可以抑制修饰酶的活性,逆转肝癌细胞异常的组蛋白修饰模式,从而达到治疗肿瘤的目的。对组蛋白修饰、相关修饰酶及其抑制剂的进一步研究,不仅有助于深入了解肝癌的发病机制,而且对于肝癌的诊断、防治和预后判断均有深远影响。     

The hinge region in androgen receptor control

The region between the DNA-binding domain and the ligand-binding domain of nuclear receptors is termed the hinge region. Although this flexible linker is poorly conserved, diverse functions have been ascribed to it. For the androgen receptor (AR), the hinge region and in particular the (629)RKLKKL(634) motif, plays a central role in controlling AR activity, not only because it acts as the main part of the nuclear translocation signal, but also because it regulates the transactivation potential and intranuclear mobility of the receptor. It is also a target site for acetylation, ubiquitylation and methylation. The interplay between these different modifications as well as the phosphorylation at serine 650 will be discussed here. The hinge also has an important function in AR binding to classical versus selective androgen response elements. In addition, the number of coactivators/corepressors that might act via interaction with the hinge region is still growing. The importance of the hinge region is further illustrated by the different somatic mutations described in patients with androgen insensitivity syndrome and prostate cancer. In conclusion, the hinge region serves as an integrator for signals coming from different pathways that provide feedback to the control of AR activity.     

正常和腺样囊性癌涎腺中赖氨酸18位点乙酰化组蛋白H3表达的研究

目的探讨赖氨酸18位点（lysine 18 site,lys18）乙酰化组蛋白H3（acetyl-histone H3）在涎腺腺样囊性癌（adenoid cystic carcinoma,ACC）和正常涎腺中表达的意义。方法免疫组织化学Envision二步法检测60例ACC和49例正常涎腺中lys18乙酰化组蛋白H3的表达,分析其与ACC发生部位、组织学分级、临床分期、神经侵犯等肿瘤临床病理特征的关系。结果正常涎腺中导管细胞、腺泡细胞以及ACC肿瘤细胞中均有lys18乙酰化组蛋白H3阳性表达,表达位于细胞核。但lys18乙酰化组蛋白H3在ACC中的表达显著低于正常涎腺（χ2=46.745,P=0.000 1）,且其表达与ACC的临床病理特征没有相关性（P〉0.05）。结论组蛋白H3 lys18低乙酰化可能与ACC的肿瘤发生有关。     

支气管哮喘患者外周血组蛋白去乙酰化酶9的表达及其意义

目的 探讨支气管哮喘(简称哮喘)患者外周血组蛋白去乙酰化酶9 (Histone Deacetylase 9,HDAC9)的表达特征及其与Th2、Th17、调节性T细胞的关系.方法 选择2010年3月至2011年6月上海瑞金医院呼吸科47例慢性持续期哮喘患者,分为间歇期哮喘组、轻度哮喘组和中重度哮喘组,各组均行肺功能检查和哮喘控制问卷调查哮喘控制情况.并选取20名健康人作为健康对照组.通过分离外周血单个核细胞(PBMCs),Trizol法抽提RNA,采用荧光实时定量方法检测转录因子GATA3、IL-4、HDAC9mRNA表达水平.ELISA检测血浆中Th17细胞分泌的主要细胞因子IL-17以及调节性T细胞分泌的主要细胞因子——转化生长因子( TGF)-β表达水平.结果 哮喘组PBMCs中GATA3、IL-4mRNA总体相对表达水平分别为28.12±7.57、743.6±312.8高于健康对照组相对表达水平(分别为0.56±0.22、0.7±0.8),差异有统计学意义(U值分别为16.00和37.00,P ＜0.01),HDAC9 mRNA在间歇期、轻度、中重度哮喘患者中的表达水平分别为3.20±0.50、89.6±18.0和323.0±65.3,呈逐渐上升趋势,各组间差异有统计学意义(H=11.32,P＜0.05).同时,哮喘患者总体血浆细胞因子IL-17表达水平为83±55,高于健康对照组的34±22(U=153.50,P＜0.01),而TGF-β表达水平下降趋势,组间无统计学差异.HDAC9 mRNA表达水平与GATA3 mRNA表达水平呈正相关(r =0.482,P＜0.05),与IL-4 mRNA表达水平呈正相关(r=0.432,P＜0.05),与IL-17水平呈现正相关(r=0.538,P＜0.05),与TGF-β表达水平呈负相关(r=-0.417,P＜0.05).在中重度哮喘患者中,HDAC9mRNA水平与肺功能FEV1占预计值％呈负相关(r=-0.657,P＜0.05).结论 哮喘患者PBMCs中HDAC9mRNA表达水平随病情严重程度逐渐升高,其升高不仅与哮喘发病相关的Th2细胞特征性转录因子GATA3、细胞因子IL-4 mRNA表达水平以及Th17、Treg分泌的细胞因子水平密切相关,且与哮喘患者FEV1占预计值％密切相关.     

Clinical and Pathologic Impact of Select Chromatin-modulating Tumor Suppressors in Clear Cell Renal Cell Carcinoma

Background

Historically, VHL was the only frequently mutated gene in clear cell renal cell carcinoma (ccRCC), with conflicting clinical relevance. Recent sequencing efforts have identified several novel frequent mutations of histone modifying and chromatin remodeling genes in ccRCC including PBRM1, SETD2, BAP1, and KDM5C. PBRM1, SETD2, and BAP1 are located in close proximity to VHL within a commonly lost (approximately 90%) 3p locus. To date, the clinical and pathologic significance of mutations in these novel candidate tumor suppressors is unknown.

Objective

To determine the frequency of and render the first clinical and pathologic outcome associated with mutations of these novel candidate tumor suppressors in ccRCC.

Design, setting, and participants

Targeted sequencing was performed in 185 ccRCCs and matched normal tissues from a single institution. Pathologic features, baseline patient characteristics, and follow-up data were recorded.

Outcome measurements and statistical analysis

The linkage between mutations and clinical and pathologic outcomes was interrogated with the Fisher exact test (for stage and Fuhrman nuclear grade) and the permutation log-rank test (for cancer-specific survival [CSS]).

Results and limitations

PBRM1, BAP1, SETD2, and KDM5C are mutated at 29%, 6%, 8%, and 8%, respectively. Tumors with mutations in PBRM1 or any of BAP1, SETD2, or KDM5C (19%) are more likely to present with stage III disease or higher (p = 0.01 and p = 0.001, respectively). Small tumors (<4 cm) with PBRM1 mutations are more likely to exhibit stage III pathologic features (odds ratio: 6.4; p = 0.001). BAP1 mutations tend to occur in Fuhrman grade III–IV tumors (p = 0.052) and are associated with worse CSS (p = 0.01). Clinical outcome data are limited by the number of events.

Conclusions

Most mutations of chromatin modulators discovered in ccRCC are loss of function, associated with advanced stage, grade, and possibly worse CSS. Further studies validating the clinical impact of these novel mutations and future development of therapeutics remedying these tumor suppressors are warranted.     

Radiosynthesis and preliminary evaluation of an 18F-labeled tubastatin A analog for PET imaging of histone deacetylase 6

Histone deacetylase 6 (HDAC6) is a unique member of the HDAC family because of its characteristics, namely, its cytoplasmic localization and ubiquitin binding. HDAC6 has been implicated in cancer metastasis and neurodegeneration. In the present study, we performed radiosynthesis and biological evaluation of a fluorine-18–labeled ligand [¹⁸F] 3 , which is an analog of the HDAC6-selective inhibitor tubastatin A, for positron emission tomography (PET) imaging. [¹⁸F] 3 was synthesized by a two-step reaction composed of ¹⁸F-fluorination and formation of a hydroxamic acid group. IC₅₀ values of 3 against HDAC1 and HDAC6 activities were 996 nM and 33.1 nM, respectively. A biodistribution study in mice demonstrated low brain uptake of [¹⁸F] 3 . Furthermore, bone radioactivity was stable at around 2% ID/g after injection, suggesting high tolerance to defluorination. Regarding metabolic stability, 70% of the compound was observed as the unchanged form at 30 minutes post injection in mouse plasma. A small animal PET study in mice showed that pretreatment with cyclosporine A had no effect on initial brain uptake of [¹⁸F] 3 , suggesting low brain uptake of [¹⁸F] 3 was not caused by the P-glycoprotein–mediated efflux. While PET imaging using [¹⁸F] 3 has a limitation with respect to neurodegenerative diseases, further studies evaluating its utility for certain cancers are worth evaluating.     

SET8 Inhibition Potentiates Radiotherapy by Suppressing DNA Damage Repair in Carcinomas

Objective SET8 is a member of the SET domain-containing family and the only known lysine methyltransferase(KMT) that monomethylates lysine 20 of histone H4(H4 K20 me1). SET8 has been implicated in many essential cellular processes, including cell cycle regulation, DNA replication, DNA damage response, and carcinogenesis. There is no conclusive evidence, however, regarding the effect of SET8 on radiotherapy. In the current study we determined the efficacy of SET8 inhibition on radiotherapy of tum...     

丙戊酸联合伏立诺他增强阿糖胞苷对人Dami白血病细胞株杀伤作用的机制研究

目的探讨丙戊酸(VPA)联合伏立诺他(SAHA)增强阿糖胞苷(Ara-c)对人Dami白血病细胞株的杀伤作用,并探讨其分子学机制。方法设空白对照组、Ara-c组、VPA组、SAHA组、VPA+Ara-c组、SAHA+Ara-c组,VPA+SAHA+Ara-c组,分别作用于对数生长期的Dami白血病细胞,MTT比色法检测药物对细胞的生长抑制作用;用PI法通过流式细胞仪检测细胞周期;RT-PCR方法检测转录因子GATA-1、胞苷脱氨酶(CDA)及脱氧胞苷激酶(DCK)mRNA水平的变化。结果 VPA和SAHA共同联合Ara-c用药组细胞生长抑制率明显高于VPA联合Ara-c组及SAHA联合Ara-c组,各组间相比,具有显著性差异。Dami细胞经过VPA和SAHA处理后均出现细胞周期阻滞现象,主要阻滞在G1期,与对照组相比差异有显著性(P0.05);VPA和SAHA联合用药组G1期细胞所占比例高于SAHA组(P0.05),与VPA组差异无显著性(P0.05)。VPA组、SAHA组、VPA和SAHA联合用药组GATA-1和CDA mRNA表达水平均低于对照组(P0.05),各组间差异无显著性(P0.05);VPA组DCK mRNA表达水平高对照组(P0.05)、SAHA组与对照组比较差异无显著性(P0.05)、VPA和SAHA联合用药组DCK mRNA表达水平高于VPA组和SAHA组(P0.05)。结论 VPA联合SAHA可增强阿糖胞苷对Dami白血病细胞的杀伤作用,可能是通过增加DCK的表达,从而增加阿糖胞苷体内活性代谢产物所致。