TSA对人肝癌细胞SMMC-7721的抑制作用及其机制

目的:研究去乙酰化转移酶抑制剂TSA对肝癌细胞SMMC-7721的作用及其机理。方法:利用细胞计数,流式细胞仪分析细胞凋亡及细胞周期,Tunel试验研究TSA对肝癌细胞SMMC-7721的作用;利用western研究TSA对肝癌细胞蛋白表达的影响。结果:TSA可明显抑制肝癌细胞SMMC-7721的生长,并可诱导细胞凋亡。可阻滞肝癌细胞SMMC-7721细胞周期于G0/G1期。可增加p53,p21,bax等基因的表达,降低BCL-2的表达。结论:去乙酰化转移酶抑制剂TSA可明显抑制肝癌细胞SMMC-7721的生长并诱导其凋亡,其主要通过调控一些肿瘤相关基因的表达起作用。     

检测胸水碱性蛋白,癌胚抗原和唾液酸监测临床治疗

以联合检测晚期肺癌明水中TBP、CEA和TSA变化对临床治疗进行动态观察，结果62例病人有85．48％的TBP阳性率在出现明显疗效时降为32．26％；CEA和TSA水平也分别由治疗前的26．69μg／L、32.35μg／L和583．42mg／L、559．18mg／L降至6．21μg／L、8．44μg／L和349．64mg／L、396．29mg／L。因此认为三项指标的联合检测可以监测晚期肺癌的临床治疗，对经治医生适时地调整治疗方案有一定的指导作用。     

腰椎椎弓根通道不同外偏角方向变化规律的数字解剖学研究

目的:探讨腰椎椎弓根在0°头尾偏角和不同外偏角方向通道的变化规律。方法:1例健康成人腰椎CT连续扫描数据集,应用Mimics8.11三维重建腰椎数字解剖模型,将腰椎数字模型导入Surface10.0,确定椎骨正中矢状切面和经椎弓根中部水平面为0°正交平面,0°水平面为0°头尾偏角参考平面,正中矢状切面为0°内外偏角参考平面,确定左右椎弓根各个方向通道的正投影,获得椎弓根通道的正投影内边界及内边界内、外切圆,获得内切圆在正投影方向经椎板、椎弓根与椎体的通道长度及各内、外切圆圆心坐标值、半径大小,对获取相关数据进行定量分析与可视化显示。结果:L1~5左右椎弓根通道在0°头尾偏角和不同外偏角方向正投影区内边界的内切圆半径随外偏角的增大逐渐增大而后又逐渐减小,其中最大半径值对应的角度方向为最佳角度方向,外切圆半径没有明显变化;L1~5左右椎弓根通道正投影区内边界内切圆通道长度随外偏角的增大呈逐渐增大趋势。结论:腰椎椎弓根通道大小是随外偏角方向不同而不同的连续的动态变化过程,应用数字技术可以获得其通道大小连续的动态的变化规律,临床应用选择合适直径、长度大小的螺钉及确定最佳进钉方向需要依循这一规律。     

组蛋白去乙酰化酶抑制剂TSA诱导人乳腺癌细胞凋亡及自噬

目的 探讨组蛋白去乙酰化酶抑制剂曲古霉素(TSA)对人乳腺癌细胞凋亡及自噬的作用及其可能的分子机制。方法采用MTT法检测T47D细胞的增殖能力;流式细胞术检测细胞凋亡的变化;Western blot法检测凋亡及自噬相关蛋白的表达。结果 TSA对人乳腺癌细胞T47D具有增殖抑制作用(P0.05);TSA诱导T47D细胞发生凋亡,下调BCL-2/Bax比值,上调Caspase-3的表达(P0.05);同时自噬相关蛋白LC3B及Beclin-1的表达也明显增加(P0.05,P0.01)。结论 TSA体外能抑制乳腺癌细胞的增殖,其机制与诱导细胞凋亡和自噬作用有关。     

Removal of hydrogen peroxide by a 1-cysteine peroxiredoxin enzyme of the filarial parasite Dirofilaria immitis

Prior studies have shown that filarial nematodes can effectively metabolize hydrogen peroxide in excess of that generated by activated host cells. However, the mechanisms of H₂O₂ removal by the filarial parasites are unclear. Herein we report the results of studies carried out on the biochemical activity and on immunolocalization of a recombinant peroxiredoxin (Prx) enzyme from the dog filarial parasite Dirofilaria immitis. A full-length cDNA encoding a 1-Cys Prx enzyme from the dog heartworm D. immitis was expressed in Escherichia coli as a recombinant polyhistidine fusion protein (rDiPrx-1). rDiPrx-1 was capable of reducing H₂O₂ in the presence of dithiothreitol. The apparent kinetic constants determined for DiPrx-1 using H₂O₂ as a substrate were a Michaelis constant (K _m) of 16.28 mM and a maximal velocity (v _max) of 16 μmol min⁻¹. Consistent with the enzyme activity, D. immitis adult worms could detoxify exogenously added H₂O₂ in vitro. Antibodies to rDiPrx-1 identified a 27-kDa native antigen in parasite extracts and larval and adult excretory-secretory products. The antibodies were used to localize the native antigen to the lateral hypodermal chords of both male and female worms by immunohistochemistry. In addition, labeling was seen in the afibrillar muscle cells in male worms and in some areas of the uterine wall in female worms. Thus, DiPrx-1 is the first parasite Prx to be shown to detoxify exogenously added H₂O₂ in an in vitro system. Received: 20 July 1999 / Accepted: 8 September 1999     

Anti-neuroblastoma activity of Helminthosporium carbonum (HC)-toxin is superior to that of other differentiating compounds in vitro

Treatment of high-risk neuroblastoma (NB) is difficult. Novel therapeutics improving survival rates are urgently required. We have previously shown that the histone deacetylase inhibitor (HDACI) Helminthosporium carbonum (HC)-toxin induces differentiation of neuroblastoma (NB) cells. Here, we show that HC-toxin inhibits the growth of both established NB cell lines and primary cultures with and without amplified MYCN stronger than retinoids (RAs) and other HDACIs (MS-275, n-butyric acid, suberoylanilide hydroxamic acid, trichostatin A, valproic acid). Nanomolar dosages suppress E2F-1, N-myc, Skp2, Mad2 and survivin proteins, found at high levels in high-risk NBs, more efficiently than both RAs and other HDACIs. The level of hypophosphorylated active retinoblastoma (RB) tumor suppressor protein is increased most effectively. HC-toxin's epoxy group is essential for inhibiting HDACs and promoting anti-NB activity. Without this functional group, those cellular effects are not observed. In conclusion, the anti-NB activity of HC-toxin is superior to that of RAs and that of all other HDACIs tested.     

古抑菌素A对肝癌细胞HepG2中抑癌基因FHIT表达的影响

目的：探讨去乙酰化转移酶抑制剂古抑菌素A（trichostatin A,TSA）对人肝癌HepG2细胞生长的作用以及FHIT表达的影响。方法：体外培养人肝癌细胞株HepG2,分为对照组和不同浓度（5、50、250、500、1000nmol/L）TSA组,作用24h和48h后在倒置显微镜下观察细胞形态改变,CCK-8法检测TSA对HepG2细胞增殖的影响,实时荧光定量RT-PCR法检测FHIT基因的表达。结果：倒置显微镜下,经TSA处理的细胞增殖速度显著减慢,出现凋亡早期改变,与对照组相比,TSA可明显抑制HepG2的增殖,且呈时效和剂量依赖关系（P〈0.01）,荧光定量PCR结果显示TSA可以使FHIT表达上调（P〈0.01）。结论：TSA对肝癌HepG2细胞体外生长有明显抑制作用,可能与促进FHIT表达有一定关系。