酪氨酸激酶抑制剂类抗肿瘤药物研究方法进展

酪氨酸激酶(protein tyrosine kinases,PTKs)在肿瘤细胞的增殖、分化、迁移、侵袭等相关信号通路中起到了关键的调控作用,已经成为肿瘤靶向性治疗的重要靶点.本文对靶向酪氨酸激酶的小分子抑制剂的筛选和评价方法进行综述,以期促进酪氨酸激酶抑制剂类抗肿瘤药物的研究.     

脊髓损伤中RhoA/ROCK通路的作用机制研究

脊髓损伤是一种严重的中枢神经系统损伤,常导致患者瘫痪或死亡,预后差。脊髓损伤主要包括机械损伤和继发性损伤两个过程。在继发性损伤过程中,多种信号通路被激活,在脊髓损伤的发病机制中起重要作用,其中,RhoA/Rho信号通路在脊髓变性和再生中起着特殊的作用。本文讨论RhoA/Rho激酶信号介导的脊髓发病机制,以及针对RhoA/ROCK通路靶向药物的治疗进展。     

蛋白激酶B/Akt抑制剂

磷脂酰肌醇-3-激酶(phosphatidylinositol 3-kinase,PI3K)/蛋白激酶B(protein kinase B,PKB/Akt)信号通路在细胞生长与存活中起着关键作用,PI3K/Akt通路的过度激活在多种肿瘤中常见。Akt激酶本身以及Akt激酶上游调节分子,例如PTEN和PI3K,在超过50%的人类肿瘤中均有异常变化。因此Akt成为肿瘤预防和肿瘤靶向治疗的热点之一。许多小分子化合物通过不同机制抑制Akt活性,根据小分子抑制剂与激酶的结合部位和化学结构不同,主要分为ATP竞争性抑制剂、Akt变构抑制剂和磷脂酰肌醇类似物抑制剂。本文综述了PI3K/Akt通路与肿瘤的关系和Akt抑制剂的研究现状,为新型抗癌药物的设计研究提供参考。     

靶向EGFR家族的抗肿瘤药物研究进展

表皮生长因子受体（EGFR,ErbB）家族在肿瘤的发生、发展中具有重要的作用。很多实体肿瘤中存在EGFR家族受体过表达或异常激活。靶向EGFR家族的抗肿瘤药物研发已经成为一个热点领域,并且成功地应用于临床。靶向EGFR家族的抗肿瘤药物可以分为单克隆抗体和小分子酪氨酸激酶抑制剂两大类。单克隆抗体与受体胞外区结合阻止配体．受体的结合或者阻止配体结合引起的受体活化;而小分子酪氨酸激酶抑制剂则结合于胞内激酶区,抑制激酶自磷酸化和下游信号通路激活。     

PDZ连接激酶，又一新的原癌基因

PDZ连接激酶(PBK)是一种丝-苏氨酸激酶,属于丝裂原活化蛋白激酶激酶(MAPKK)家族成员. PBK能调控细胞周期进程,促进细胞增殖.近年发现,其在乳腺癌、结肠癌、皮肤癌和前列腺癌等多种恶性肿瘤组织中均呈高表达,与多种癌症预后不良关联密切. PBK主要通过Wnt、PI3K/AKT/mTOR和MAPK等信号通路,调控肿瘤细胞有丝分裂,参与多种癌症的增殖、侵袭转移和耐药等,并受miR-216b-3p、miR-770-5p和miR-372-5p等多种microRNA调控.提示PBK可能作为又一新的原癌基因,有望成为抑癌药物新的分子靶点.     

靶向FGFR信号通路在肿瘤治疗中的进展

成纤维生长因子受体(FGFRs)是一类高度保守的跨膜受体酪氨酸激酶(RTKs),它调控着细胞的许多正常生理功能。大量的研究表明,异常激活的FGFR与肿瘤的发生和血管的生成密切相关。靶向FGFR的药物则可以通过抑制该信号通路从而达到抗癌的作用。目前,多款针对FGFR的小分子抑制剂、单抗类药物已经进入临床。本综述主要介绍紊乱的FGFR信号通路与肿瘤的关系和几款具有代表性的FGFR药物在临床测试阶段的情况。     

非小细胞肺癌靶向治疗的临床前研究进展

针对表皮生长因子受体（EGFR）和血管生成（angiogenesis）信号通路的靶向治疗已经在晚期非小细胞肺癌的治疗上取得成功,但由于抗药性的存在,大多数晚期患者的生存时间仍然提高有限。继发性的EGFR T790M突变和原癌基因肝细胞生长因子受体（MET）的扩增被鉴定为两种主要的抗药机制。最近转化生长因子-β（TGF-β）/白介素-6信号通路被报道能介导选择性和适应性地对erlotinib的抗药。另一方面,Kras突变所致肺癌的靶向治疗方面也取得了一些进展。双重抑制磷脂酰肌醇3-激酶（PI3K）和促分裂素原活化蛋白激酶激酶（MEK）信号通路可导致Kras突变肿瘤的显著消退,联合抑制SRC、PI3K和MEK可使丝氨酸/苏氨酸蛋白激酶11（Lkb1）缺失,Kras突变的肺癌小鼠的肿瘤明显消退,抑制核因子-κB（NF-κB）信号通路导致p53缺失,Kras突变的肿瘤发展显著减慢。这些发现都为发展非小细胞肺癌患者的靶向治疗提供了有力的支持。     

NF-κB抑制剂通过逆转LPS诱导的BMPRⅡ下调改善肺血管重构

动脉性肺动脉高压(pulmonary arterial hypertension, PAH)的发生、发展与骨形态发生蛋白受体II型(bone morphogenetic protein receptor type II, BMPRII)编码基因的遗传突变和核因子κB (nuclear factorκB, NF-κB)通路介导的炎症反应密切相关。本文旨在研究NF-κB通路抑制剂对脂多糖(lipopolysaccharide, LPS)诱导的肺动脉内皮细胞损伤的作用。用1μg/mL的LPS处理人肺动脉内皮细胞,用免疫印迹和qPCR检测BMPRII和白介素8 (interleukin-8, IL-8)的表达水平。腹腔注射野百合碱(monocrotaline, MCT)建立大鼠PAH模型,用免疫荧光染色法检测肺动脉内皮细胞BMPRII和IL-8的表达情况,检测模型大鼠心脏血流动力学变化和肺血管重构情况。结果显示,LPS可引起人肺动脉内皮细胞BMPRII的表达下调和IL-8的表达上调,NF-κB抑制剂BAY11-7082 (10μmol/L)可逆转LPS的作用。在MCT-PAH大鼠模型中,肺动脉内皮细胞BMPRII表达下调,IL-8表达上调,右心室/(左心室+室间隔)重量比值[weight ratio of right ventricle to left ventricle plus septum, RV/(LV+S)]和右心室收缩压(right ventricular systolic pressure, RVSP)显著升高,心输出量(cardiac output, CO)和三尖瓣环收缩期位移(tricuspid annular plane systolic excursion, TAPSE)明显降低,肺血管壁明显增厚,连续21天腹腔注射BAY11-7082 (5 mg/kg)可逆转上述变化。以上结果提示,LPS通过NF-κB信号通路下调BMPRII的表达水平,促进PAH的发生、发展,因此NF-κB信号通路可作为PAH潜在治疗靶点。     

Ⅰ型神经纤维瘤病相关信号通路及微环境组分异常

Ⅰ型神经纤维瘤病(neurofibromatosis type 1, NF1)是一种由NF1基因突变导致的常染色体显性遗传病,以多发皮肤咖啡斑和神经纤维瘤为主要特征,国际上针对NF1尚无规范治疗策略。NF1基因庞大,其编码的神经纤维蛋白(neurofibromin, NF)参与细胞增殖调控,该病发病机制复杂,为药物研发带来较大挑战。在NF1信号通路方面,丝裂原活化蛋白激酶的激酶的激酶/丝裂原活化蛋白激酶的激酶/丝裂原活化蛋白激酶通路(RAF/MEK/ERK)、磷脂酰肌醇3激酶/蛋白激酶B/哺乳动物雷帕霉素靶蛋白通路(PI3K/AKT/mTOR)、无翅蛋白/β联蛋白通路(WNT/β-catenin)、河马蛋白/转录共激活子/YES相关蛋白通路(HIPPO/TAZ/YAP)等均有研究,其中针对RAF/MEK/ERK通路的MEK1/2抑制剂药物已上市,即司美替尼(selumetinib),用于治疗NF1和不能手术的丛状神经纤维瘤(plexiform neurofibroma, PNF)患者。近年研究发现,NF1肿瘤微环境包括施万细胞(Schwann cells, SCs)及其前体、肥大细胞、...     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.