叶黄素的抗癌作用及其研究现状

叶黄素是自然界广泛存在的类胡萝卜素,可以提高人体的免疫能力,也是一种抗氧化剂,对老年视黄斑退行性变化有很好的预防作用,但更重要的是研究表明,叶黄素对一些类型的癌症具有预防效果。本综述了近年来有关叶黄素预防癌症作用的流行病学调查、分析,以及与癌症关系的实验研究及作用机制等方面的研究进展。     

植物多酚的防癌抗癌作用

植物多酚是植物中广泛存在的一大类多酚化合物的总称,包括多酚（如单宁）、黄酮、酚酸等。体外实验研究表明植物多酚对多种人癌细胞具有增殖抑制作用,抑制动物体内肿瘤生长。其作用机理与抗氧化、调控细胞周期、诱导肿瘤细胞凋亡和分化、影响血管生成和肿瘤细胞信号传导等有关。对植物多酚的防癌抗癌作用,值得进一步深入研究。     

家蚕抗菌肽的抗癌作用

从家蚕（Ｂｏｍｂｙｘｍｏｒｉ）免疫蛹血淋巴中提取抗菌肽,以Ｓ１８０荷瘤小鼠和艾氏腹水瘤荷瘤小鼠为模型,研究抗菌肽的抗癌效应,结果表明,抗菌肽明显抑制Ｓ１８０瘤重,３７９２,４５４２和４９８０Ｕ３种剂量抑瘤作用分别为４２．８６％,３９．１３％和３７．８９％,抗菌肽对外周血白细胞数没有影响。病理切片显示,注射抗菌肽荷瘤小鼠癌瘤组织大面积坏死,癌瘤周围组织内有大量炎细胞（单核细胞,中性粒细胞和淋巴细胞）     

生物类黄酮抗癌作用研究进展

生物类黄酮广泛分布于植物源食物中,具有广泛的生理和药理作用,如具有抗癌和抗突变作用,可以抑制肿瘤的形成,这些功能与其显著的抗氧化、抗自由基作用等密切相关。笔者就类黄酮抗癌作用的研究进展作一综述。     

番茄红素与癌

番茄红素是主要的类胡萝卜素之一,最近的科学研究发现,它对人类健康有重要的作用。本文介绍了番茄红素的食物来源、生物合成、物理化学特性和生理活性,它的抗癌效果与其抗氧化活性有关。很多的流行病学研究证明,番茄红素对一些类型的癌有预防效果,如前列腺癌和消化道癌。体内和体外的癌细胞培养研究也支持这一结论。因此,具有广泛用途的番茄红素,将有希望成为最重要的一个化学防癌物质。     

灵芝多糖的抗癌构效关系及其抗癌作用机制

灵芝多糖是灵芝的主要抗癌活性成分,但灵芝多糖的抗癌构效关系和抗癌机制仍不明了。现有的研究表明,具有抗癌活性的灵芝多糖大多是β-(1→3)-D-葡聚糖。β-葡聚糖中分支度高的有较高的活性,分子量高的也较分子量小的活性大。但新近的一些研究发现,含有其它结构的灵芝多糖和某些小分子量的灵芝多糖也具有免疫调节和抗癌活性。因此,这些灵芝多糖在灵芝抗癌中的作用不可忽视。灵芝多糖的抗癌作用机制目前尚不明了。现已知通过免疫介导作用发挥抗癌作用是灵芝多糖抗癌的主要机制之一。新近的研究发现,膜Ig和TLR-4为灵芝多糖激活机体B细胞的免疫受体,TLR-4也与灵芝多糖激活机体巨噬细胞有关。此外,灵芝多糖抗癌的可能机制还包括活化促分裂原活化蛋白(MAP)激酶,以及抑制肿瘤血管新生等。     

组蛋白脱乙酰酶抑制剂的抗癌作用

组蛋白乙酰转移酶和组蛋白脱乙酰酶分别催化组蛋白的乙酰化和脱乙酰基反应,调节组蛋白的乙酰化水平,从而调控基因表达。这些过程与恶性肿瘤的发生具有密切的关系。组蛋白脱乙酰酶抑制剂通过增加细胞内组蛋白的乙酰化程度,调节多种基因的表达水平,抑制肿瘤细胞的增殖、诱导细胞分化和凋亡。该文从抑制细胞增殖、诱导细胞分化、诱导细胞凋亡和抗血管形成等4个方面介绍组蛋白脱乙酰酶抑制剂的抗癌机制,并简要介绍它们的分类。     

类胡萝卜素裂解双加氧酶及其生理功能

类胡萝卜素是一大类结构相似的化合物,其裂解途径主要有羟化酶途径、双加氧酶裂解途径和氧化酶途径。类胡萝卜素经羟化酶途径可最终转化成脱落酸,经氧化酶途径则最终转化成维生素A;而在裂解双加氧酶(carotenoid cleavage dioxygenases,CCDs)催化下,类胡萝卜素氧化成脱辅基类胡萝卜素。AtCCDs是包括9个成员的小基因家族,CCD1影响果实的色泽和风味;CCD7和CCD8分别编码一个质体区域化蛋白,并参与侧根、侧芽的萌发。9-顺式-环氧类胡萝卜素双氧合酶(NCED)催化的裂解是ABA合成的关键步骤。本文对类胡萝卜素裂解途径及相关酶类的生理功能进行了综述。     

眼镜蛇毒及其组分C对大鼠实验性肝癌抗癌作用的病理学研究

目的 观察眼镜蛇毒及其组分Ｃ抗小鼠肝癌的病理学改变。方法 采用不同剂量眼镜蛇毒及其抗癌活性组分Ｃ与ＢＡＬＡ／ｃ小鼠腹水型肝癌细胞体外孵育,空白对照组用生理盐水与肝癌细胞孵育,然后取孵育液接种于小鼠前肢腋下,接种后第１０ｄ坏死,解剖取出瘤结,进行病理组织学研究。     

眼镜蛇毒及其组分C对小鼠实验性肝癌抗癌作用的病理学研究

目的　观察眼镜蛇毒及其组分 Ｃ 抗小鼠肝癌的病理学改变。 方法　采用不同剂量眼镜蛇毒及其抗癌活性组分 Ｃ 与 Ｂ Ａ Ｌ Ａ／ｃ 小鼠腹水型肝癌细胞体外孵育, 空白对照组用生理盐水与肝癌细胞孵育, 然后取孵育液接种于小鼠前肢腋下, 接种后第 １０ｄ 处死, 解剖取出瘤结, 进行病理组织学研究。 结果　空白对照组瘤结较大, 显微镜下见瘤细胞生长活跃、核大、核仁明显、核分裂多见, 而坏死灶少见, 且瘤细胞向周围浸润扩散; 治疗组瘤体较小, 瘤细胞固缩、核仁不明显、核分裂少见, 而坏死灶多见, 瘤细胞周围有纤维组织增生围绕, 限制了瘤细胞向周围蔓延浸润。 结论　眼镜蛇毒及其组分 Ｃ 对小鼠实验性肝癌的体外抗癌作用是明显的, 不同剂量及不同孵育时间的抗癌作用亦显著不同, 其中组分 Ｃ 对抗癌作用最强。     

真核基因的快速克隆及表达

以细胞间隙连接蛋白基因Cx26作为目的基因,通过T-A载体介导,构建真核表达重组载体pcDNA3.1( ) /Cx26,重组表达载体转染人鼻咽癌细胞株HNE1,表达Cx26间隙连接蛋白。     

The relationship between gene dosage,gene expression,and sex in Drosophila

In Drosophila, the ratio of the number of X chromosomes to sets of other chromosomes initiates a series of events which result in sexual differentiation. In addition, this ratio establishes dosage compensation, a mechanism which equalizes the products of X-linked genes in males and females. The present review discusses possible genetic entities responsible for the interpretation of chromosomal sex and subsequent sex-mediated regulation during development.     

NDRG4基因的表达调控及生物学效应研究进展

NDRG是近年来发现的新的基因家族,被认为与细胞分化和肿瘤形成有关。其中NDRG4基因在心脑组织中特异性高表达,并且参与正常心脑功能的维持。此外,NDRG4基因的异常表达与某些肿瘤的发生发展关系密切,因此备受关注。就NDRG4基因的调控机制、生物学效应以及与肿瘤的关系作一综述,为人们对其进一步探索提供帮助。     

Tumor-specific gene expression patterns with gene expression profiles

Gene expression profiles of 14 common tumors and their counterpart normal tissues were analyzed with machine learning methods to address the problem of selection of tumor-specific genes and analysis of their differential expressions in tumor tissues. First, a variation of the Relief algorithm, “RFE_Relief algorithm” was proposed to learn the relations between genes and tissue types. Then, a support vector machine was employed to find the gene subset with the best classification performance for distinguishing cancerous tissues and their counterparts. After tissue-specific genes were removed, cross validation experiments were employed to demonstrate the common deregulated expressions of the selected gene in tumor tissues. The results indicate the existence of a specific expression fingerprint of these genes that is shared in different tumor tissues, and the hallmarks of the expression patterns of these genes in cancerous tissues are summarized at the end of this paper.     

Structure and expression of a root-specific rice gene

Two rice cDNA clones (COS6 and COS9) were isolated, corresponding to genes that were highly expressed in roots from seedlings and mature plants. A genomic clone (GOS9) corresponding to cDNA clone COS9 was isolated and the intron/exon structure was determined by comparing the nucleotide sequences of the mRNA and the genomic clone. 5 ends and 3 ends of the mRNA were determined by primer extension and S1-nuclease mapping respectively. The open reading frame present in GOS9 potentially encodes a protein (14kDa) that does not show any significant homology to other proteins in databases.     

Tumor-specific gene expression patterns with gene expression profiles

Gene expression profiles of 14 common tumors and their counterpart normal tissues were analyzed with machine learning methods to address the problem of selection of tumor-specific genes and analysis of their differential expressions in tumor tissues. First, a variation of the Relief algorithm, "RFE_Relief algorithm" was proposed to learn the relations between genes and tissue types. Then, a support vector machine was employed to find the gene subset with the best classification performance for distinguishing cancerous tissues and their counterparts. After tissue-specific genes were removed, cross validation experiments were employed to demonstrate the common deregulated expressions of the selected gene in tumor tissues. The results indicate the existence of a specific expression fingerprint of these genes that is shared in different tumor tissues, and the hallmarks of the expression patterns of these genes in cancerous tissues are summarized at the end of this paper.