多药耐药相关蛋白1、谷胱甘肽S转移酶和DNA拓扑酶Ⅱ在骨肉瘤中的表达

目的探讨骨肉瘤组织中多药耐药相关蛋白1(MRP1)、谷胱甘肽S转移酶(GST-π)和DNA拓扑酶Ⅱ(TopoⅡ)的表达及其与临床病理特征的关系。方法采用免疫组织化学方法检测10例正常成年骨组织和40例骨肉瘤组织中MRP1、GST-π和TopoⅡ的表达,并结合临床病理指标进行分析。结果10例正常骨组织和骨肉瘤中MRP1、GST-π和TopoⅡ阳性率分别为47.5%和0%、70.0%和20.0%、35.0%和80.0%(P<0.05),且随着骨肉瘤分化程度的降低,MRP1和GST-π表达率升高。根据肿瘤大小、患者性别、年龄及就诊前病程长短等分组,MRP1、GST-π和TopoⅡ表达无统计学意义,但与Enneking外科分期相关。结论骨肉瘤组织中有MRP1、GST-π和TopoⅡ的表达与骨肉瘤的恶性程度呈正相关,提示MRP1、GST-π和TopoⅡ可能为骨肉瘤原发耐药的重要原因之一。

胎盘型谷胱甘肽-S-转移酶和DNA拓朴酶在人骨肉瘤中的表达及其与预后的关系

目的 探讨骨肉瘤组织中胎盘型谷胱甘肽 S 转移酶 (GST π)和DNA拓朴酶Ⅱ (TopoⅡ )的表达及其与预后的关系。方法 应用免疫组化SP法检测GST π、TopoⅡ在 40例骨肉瘤中的表达 ,并结合临床资料分析其对预后的影响。结果 40例骨肉瘤中GST π和TopoⅡ的阳性表达率分别为 82 5 % (3 3 40 )和 5 2 5 % (2 1 40 ) ,其中术前化疗组TopoⅡ阳性表达率为 3 8 5 % (5 13 ) ,显著低于术前无化疗组 77 8% (2 1 2 7) (P <0 0 5 ) ,GST π的阳性表达率在两组间无显著差异 ;GST π和TopoⅡ的阳性表达率与患者的预后显著相关。结论 GST π主要参与骨肉瘤原发性耐药 ,TopoⅡ不仅参与骨肉瘤原发性耐药 ,同时也参与骨肉瘤继发性耐药 ;GST π和TopoⅡ是影响骨肉瘤预后的重要因素 ,可能成为评估骨肉瘤预后的有价值的指标。

Affinity ultrafiltration of DNA topoisomerases-targeted compounds determined with HPLC／ESI-MS for drug candidate screening

A method of screening assay is demonstrated. The approach is based on the affinity of antitumor candidates for topoisomerases. In this method, antitumor candidates are fished out using topoisomerases as targets. Traditional analysis of complex compounds typically encounters signal suppression due to the relatively low concentrations, but enzyme-affinity screening for the active compounds can effectively concentrate the desired analysts into a small volume of high concen-tration. Active compounds are separated from non-affinity compounds by ultrafiltration. The molecules-enzymes complexes that are retained on the filter are subsequently separated by acidification to obtain the topoisomerases-affinity compounds for analysis on High Performance Liquid Chromatography coupled with electrospray ionization mass spectrometric detec-tion (ESI-MS). This enzyme-affinity based screening assay provides a highly specific and efficient method that can directly screen, identify, and acquire drug candidates thus improving the accuracy and speed of high-throughput screening activities.

耐药表型GST-π、P-gp及TopoⅡ在大肠癌中的表达及其临床意义

目的 探讨大肠癌组织中胎盘型谷胱甘肽 S 转移酶 (GST π)、糖蛋白 (P gp)和DNA拓扑酶Ⅱ (TopoⅡ )的表达与临床病理和预后的关系。方法 采用免疫组化方法检测 170例大肠癌组织中GST π、P gp和TopoⅡ的表达 ,对其组织病理改变和 5年生存率进行综合分析。结果 在高、中分化及低分化大肠癌中 ,GST π阳性率分别为 56 .3%、6 5.6 %和 93.8% ;TopoⅡ阳性率为 2 5.0 %、32 8%和 6 8.8% ,P gp阳性率为 37.5%、50 .0 %和 75.0 %。GST π和TopoⅡ表达在高、低分化两组间及中、低分化两组间均有非常显著的差异 (P <0 .0 1) ,P gp表达均有显著差异 (P <0 0 5)。而在不同的年龄、性别、Duke’s分期及有无淋巴结和远处转移中 ,GST π、P gp、TopoⅡ的表达均无显著差异 (P >0 0 5)。5年内生存者GST π、P gp和TopoⅡ表达阳性率低于 5年内死亡者 ,GST π和P gp有显著差异(P <0 0 5) ,TopoⅡ有非常显著差异 (P <0 0 1)。结论 耐药表型GST π、P gp。

Nutritional Composition and Topoisomerase Inhibitor Activity of Ethnomedicinal Marine Mollusk Nerita albicilla

DNA topoisomerases （topo） I and II are molecular targets of several potent anticancer agents. Thus, inhibitors of these enzymes are potential candidates for anticancer development. Traditionally, Nerita albicilla had been used in Kei Island, Southern Maluku, Indonesia to treat liver disease including cancer. The paper reports on the chemical composition ofNerita albicilla and its topo I inhibitor ofhexane, ethyl acetate and methanol extracts. Topoisomerase-I inhibitor activity was determined using the method reported by TopoGEN. The proximate analysis described that Nerita albicilla dried powder contained 12.45% ± 0.05% moisture; 9.17% ± 0.03% ash; 62.05% ± 0.10% protein; 5.58% ± 0.08% fat; 6.60% ± 0.02% crude fiber and 4.15% ± 0.24% carbohydrate （by difference）. Furthermore, the protein consisted of 11 essential amino acids and six non-essential amino acids. It contained significant amount of branched-chain amino acids （BCAA） valine, leucine, isoleucine （a total of 187.8 mg g-1 protein） and lower content of aromatic amino acids phenylalanine, tyrosine and histidine （a total of 111.26 mg .g-1 protein）. The protein score was 92.2. The yield of hexane, ethyl acetate and methanol extracts ofNerita albicilla were 2.05% ± 0.05%, 1.56% ± 0.06% and 6.99% ± 0.14%, respectively. All extracts showed topoisomerase-I inhibitor activities. Minimum inhibitory concentration （MIC） of methanol extract was 2.50 ug mL-1. Chemical screening of the extracts showed that they contained steroidal and alkaloid compounds. The investigation revealed that Nerita albicilla contains active compounds that could be potential for nutraceutical or pharmaceutical development.

Effect of Temperature on Topological States of Circular DNA

The different topological states of circular double-stranded DNA can be defined by their linking number. The equilibrium distribution of linking number can be obtained by circularizing a linear DNA into a circle by ligase. Based on the recent experimental results that the DNA bending rigidity and twist rigidity strongly depend on temperature, the reduced bending rigidity can be approximated by g = （3.19 x10-19 - T. 4.14s10-22） erg. cm over the temperature interval （5 ~ 53） ~ C, and the temperature dependence of twist rigidity can be fitted by C （ T） = （4588.89 exp（-T/117.04）- 251.33） nm. The temperature dependence of the linking number distribution of circular DNAs can be predicted by using Monte Carlo simulation. The variance of linking number distribution on temperature is in accordance with the previous experimental results. Compared with the temperature dependence of bending rigidity, the temperature dependence of twist rigidity causes a noticeable fluctuation in linking number distribution and mainly contribute towards the variance change of linking number distribution of circular DNA. The variance of the writhe number and twist number in the equation （（ALk）21 = （（ATw）2） -b （（Wr）2） depends on the length of circular DNA. When the length of circular DNA is less than 230 nm, the variance of twist number （（ATw）2） is dominant over the variance of writhe number （（（wr）2））whereas for the condition that the length of the circular DNA is larger than 370 nm.