美国公布癌症基因图谱绘制计划

美国政府近日公布了一项癌症基因图谱绘制计划,旨在找到所有致癌基因的微小变异,从而为治疗各类癌症开创新天地。     

癌症发生的分子生物学研究方法以及生物治癌药物的开发

癌症属于一种综合性疾病,主要是由于遗传基因渐发性的突变和诱导因子逐步产生所致.从而导致正常细胞分裂周期失控,细胞分裂处于无限制状态.致使癌症发生的原因复杂,研究方向途径各异,为此我们简略地分析和介绍当前分析癌症发生的分子生物学研究方法,如cDNA微阵法,PCR技术,端粒结构变化以及DNA的甲基化等.同时,对当前生物治癌药物的方法进展进行了介绍和推介,包括单克隆抗体,癌症疫苗以及阻抑癌症发生传导系统中的抑制因子等.     

从三羧酸循环代谢异常中探寻癌症进展与治疗新思路

三羧酸循环是有氧生物获得生命活动所需能量的主要途径。整个三羧酸循环的过程需要多种酶的协同作用,产生多种中间代谢产物,以此来维持细胞稳定的生存环境。在众多参与三羧酸循环的酶中,当其中某一种或多种酶的活性发生改变时,就会有新的代谢产物生成,从而改变细胞的命运。该文以三羧酸循环中异柠檬酸脱氢酶、琥珀酸脱氢酶和延胡索酸酶的突变所引起的一系列致癌代谢物的积累为切入点,就三羧酸循环中间酶突变引起的表观遗传学改变与肿瘤发生发展的关系进行综述,以期从三羧酸循环代谢异常中,探寻癌症进展与治疗的新思路。     

《Nature》两篇文章揭示癌症研究最新进展

据生物通消息,癌症是全世界一个主要死亡原因,在2005年全世界5800万死亡总数中,癌症占所有死亡的760万（或13％）。目前对于癌症机制的研究主要集中在致癌基因,致癌信号途径引发癌症分子迁移和扩增的分子机制等方面,在本期的《Nature》杂志上,研究人员在这两方面获得新的突破。     

干细胞与癌症

有“万能细胞”之称的干细胞可用于治疗多种疾病,如心肌梗死、中风、肝硬化、糖尿病、皮肤病、帕金森氏症以及癌症等几乎所有的常见病,其中干细胞治疗癌症(恶性肿瘤)更引人关注,预示着干细胞疗法将会决定今后医学发展的未来。目前,对干细胞的研究与应用取得了重要进展。     

动物与环境污染的监测

人类的生存和发展不断反作用于环境。整个自然环境由于人类不同程度涉足已改变它本来的面貌。近年来,环境污染日益严重,已引起许多国家重视对环境污染的治理,并积极开展对环境污染的监测。     

癌症与可变剪接

可变剪接在发育、分化和癌症等过程中发挥着非常重要的作用。近年来,越来越多的研究表明可变剪接与癌症有着密切的关系,许多癌症相关基因受可变剪接调控。由于癌症特异性的剪接变体具有明显的诊断价值,使得对癌症与可变剪接的研究成为热点。简要概述了癌症相关基因的可变剪接、可变剪接变体的鉴定方法、可变剪接与癌症治疗等研究进展。     

抗癌基因及其致癌机理

近年来,分子遗传学技术的广泛应用,推动和促进了肿瘤遗传变异研究的深入发展。有关血液系恶性肿瘤的研究已确认至少有两种涉及原癌基因激活的机理是细胞恶变转化的原因。即:慢性粒细胞性白血病(CML)中c-abl原癌基因被异常激活的质变     

新的癌症治疗与诊断技术

一代全新的癌症诊疗手段初见端倪,将造福于千千万万的肿瘤患者。如果一名病人被诊断患有癌症,医生将采用新的诊断方法进行一系列检测,确定是癌基因过度表达还是发生了基因突变,其结果将指导治疗。其中新开发出的一种检测方法是检测ＨＥＲ－２／ｎｅｕ生长因子受体。在３０％～５０％的转移性乳腺癌患者中,ＨＥＲ－２／ｎｅｕ生长因子受体被ＨＥＲ－２／ｎｅｕ癌基因过度表达。ＨＥＲ－２／ｎｅｕ检测法可使专家们通过检测尿或血样中的ＨＥＲ－２／ｎｅｕ片段对病人治疗后和非侵润性肿瘤缓解后的病情进行监控。诊断和治疗缺陷性成视网膜…     

The metabolic environment of cancer

The tumor cell has a very distinctive metabolism. It acts as a metabolic trap for host nutrients thus taking vital compounds for the metabolism of the host. Depending on the particular tumor growing pattern, cancer cells use preferentially glucose or amino acids for their energetic or biosynthetic needs. Lipids, fatty acids in particular, can also be taken up by the tumor cell. In addition, it can also release some compounds into the host circulation which are not normally produced by the original cell before neoplastic transformation. Some of these compounds affect the metabolism of the host in an unfavorable way since they can oppose the host's metabolic responses, which sustain homeostasis. The final product is that the metabolic machinery of these cells allows them to grow continuously in an uncontrolled manner. The consequences of tumor invasion on the host's metabolism are varied. They have, however, one thing in common: the reduction of the metabolic efficiency of the host. Muscular protein depletion, increased gluconeogenesis, uncoupling of oxidative phosphorylation constitute the main metabolic responses of the host as a result of tumor invasion. The net result of all these metabolic changes is profound energy imbalance which normally ends with cachexia and, eventually, death.     

环境汞污染对藻类的毒性效应及其影响因素

综述了汞污染对藻类的毒性效应及影响因素。水环境中汞主要以元素汞、无机汞和有机汞3种形式存在。藻类吸附汞主要分为胞外的快速吸附和胞内的缓慢富集,在安全浓度内,金属汞对藻生长有一定的促进作用,随着浓度增大,抑制藻生长或致死。汞进入藻体细胞后,藻类为了存活会产生一系列保护机制。藻类对汞的排斥和排出作用可能就是对汞耐性的一种重要机制。藻类也可以通过多种方式减少汞进入藻类细胞,以及通过与其他物质结合汞使其排出胞外。温度、pH、生物学因素等影响重金属对藻类的毒性作用。并就藻类对汞耐性和适应机理、利用藻类修复和监测重金属污染、藻类响应汞胁迫的信号转导途径及其保护机制等未来研究领域进行了展望。     

水泥粉尘污染对水稻,油菜和土壤环境的影响

通过在水泥厂周围布设不同监测样点、样田,了解水泥粉尘沉降对水稻、油菜和土壤环境的影响。结果表明,水泥厂周围的大气环境受到不同程度的粉尘污染。水泥粉尘使一些农田水稻和油菜产量有所下降,但对质量未产生不良影响,水泥粉尘会使土壤中钙的含量明显增加。     

Breast cancer and the environment

The most recent estimate of the overall worldwide burden of cancer is that in the year 2000 more than 10 million new cancer cases occurred and approximately 6 million cancer deaths. Breast cancer accounts for about 1 in 10 cancers and is the most frequent cancer affecting women. Since 10% of all cancers in the world are breast cancer (only affecting half of the population as breast cancer almost exclusively concerns only women), it is being considered an epidemic. In terms of the absolute number of incident cases, breast cancer now ranks first not only in the industrialized world but also in the developing world. The worldwide mortality figure for the year 2000 was 370,000. However, there are marked geographical differences, with Africa and Asia currently having incidence rates some 10 times lower than those of North America and northern Europe. Studies of migrant populations have long indicated that the genetic background only plays a tiny, if any, role in these differences. Over time, clear increases have been seen in the global number of cases: from 572,000 in 1980 to 1,050,000 in 2000. This corresponds not only to a modest increase in incidence rates in countries with a long history of frequent breast cancer but also to marked increases in countries with previously low rates. The reasons for these increases are currently unexplained and a possible hypothesis relates to environmental factors. By contrast, in a number of countries in the western world mortality rates are stable, and, in the USA and the United Kingdom, even decreasing slightly. The aetiology of breast cancer has been the subject of hundreds of studies since the pioneering investigation of Lane Claypon in 1926. Risk factors belong to different domains: reproductive life, hormonal factors, diet, genetics (BRCA1, BRCA2) and exposure to radiation and selected chemicals. Yet, much breast cancer remains unexplained and new aetiological links must be sought such as occupational factors and exposure to pesticides and other endocrine disrupters. A recent international summit on breast cancer and the environment outlined the need for more research to be conducted into the effects of exposure in the vicinity of nuclear power plants or chemical landfill sites and, more generally, into contaminants in food, air, water and soil. This is particularly relevant in some parts of the world such as Africa.     

Spirostomum ambiguum as a bioindicator of aquatic environment pollution

Express-methods based on functional and morphological features of the genus Spirostomum have been applied for estimation of the effect produced by chemical toxicants, γ-radiation, electromagnetic emission, and homeopathic drugs on the aquatic environment. The experiments have shown that Sp. ambiguum is a very useful indicator for the bioassay of low-intensity physical and chemical pollution in the aquatic environment.     

The chemical environment of tubificid and lumbriculid worms according to the pollution level of the sediment

In Lake Geneva (Switzerland), 14 tubificid and 2 lumbriculid worm species were collected in a total of 170 samples of sediment. The sediment was analysed through ten chemical variables: organic carbon, total phosphorus, Cd, Zn, Sn, Pb, Hg, Cu, Cr, Mn. The chemical environment characterizing the presence of every worm species was defined by the mean value of each of these ten variables in all samples where the species was found. The multivariate comparison of the chemical environment typical of every species enabled six groups of species to be distinguished, each characterized by the high value of one chemical variable: (1) Peloscolex ferox, Potamothrix hammoniensis, Limnodrilus claparedeanus, and Cd. (2) Psammoryctides barbatus, and Zn. (3) Limnodrilus hofmeisteri, L. udekemianus, L. profundicola, and total P. (4) Potamothrix heuscheri, Aulodriluspluriseta, A. limnobius, Tubifex tubifex, Ilyodrilus templetoni, Stylodrilus heringianus, and organic C. (5) Potamothrixvejdovskyi, and, Hg. (6) Peloscolex velutinus, Stylodrilus lemani, and Mn. Pollution level of the sediment decreased from group 1 to 6, so each of these groups may be used to define a different level of pollution. The pooled coefficient of variation of the ten chemical variables used to define the chemical environment of each species diminished from group 1 to 6: the most opportunistic species colonized the most polluted areas.     

Light pollution, reproductive function and cancer risk

At present, light pollution (exposure to light-at-night) both in the form of occupational exposure during night work and as a personal choice and life style, is experienced by numerous night-active members of our society. Disruption of the circadian rhythms induced by light pollution has been associated with cancer in humans. There are epidemiological evidences of increased breast and colon cancer risk in shift workers. An inhibition of the pineal gland function with exposure to the constant light (LL) regimen promoted carcinogenesis whereas the light deprivation inhibits the carcinogenesis. Treatment with pineal indole hormone melatonin inhibits carcinogenesis in pinealectomized rats or animals kept at the standard light/dark regimen (LD) or at the LL regimen. These observations might lead to use melatonin for cancer prevention in groups of humans at risk of light pollution.     

The extracellular topographical environment influences ovarian cancer cell behaviour

The importance of the biophysical cellular environment in cancer development has been increasingly recognised but so far has been only superficially studied. Here we investigated the effect of cell-like substrate topography on ovarian cancer cell behaviour and potential underlying signalling pathways. We observed changes in cell morphology in response to substrate topography, which implies modification of structure-function associations. Differences in focal adhesion signalling and Rho/ROCK activity suggested their involvement in the biomechanically-driven cellular responses. Cell-like topography was also shown to modulate the MAPK pathway and hence potentially regulate cell proliferation. The selective regulation of the cells by the mechanotransduction pathways that we noted has wide ranging implications for understanding cancer development. We established that the physical architecture of cell culture substrate is sufficient to influence cancer cell behaviour, independent of genetic composition or biochemical milieu.     

Detection of mutagenic pollution of natural environment using microbiological assays

One of the most important and serious ecological problems is mutagenic pollution of the natural environment. Therefore, detection of mutagenic compounds in samples taken from natural habitats is of special interest. Microbiological mutagenicity tests seem to be very useful tools for such detection. In this review article, a general view on the tests employing genetically modified bacterial strains designed for detection of low concentrations of mutagenic compounds is presented. Moreover, a comparison of advantages and disadvantages of selected assays, developed early on and more recently, and features of these assays are discussed. It appears that none of the currently available mutagenicity tests is perfect or optimal for all purposes. Thus, a choice for the particular assay must depend on the nature of studies and specific tasks of the experiments to be performed.     

Mosses as bioindicators of heavy metal pollution of the urban environment

The content of some heavy metals in leafy epigeous mosses and upper soil layer of the large Moscow parks has been studied. The peculiarities in accumulation of heavy metals by different moss species have been pointed out. The content of heavy metals in leafy epigeous mosses has been found to be closely connected with the content of these elements in upper soil layer.