E2F基因与肿瘤放射敏感性研究进展

目的 肿瘤放射敏感性是影响肿瘤放射治疗效果的重要原因.在众多影响放射敏感性的因素中,细胞周期、细胞凋亡和DNA损伤修复发挥重要作用.E2F基因家族通过编码E2Fs转录因子家族,调控细胞周期、细胞凋亡等生命活动.本研究旨在总结E2F基因与肿瘤细胞放射敏感性的关系的研究进展.方法 应用PubMed、CNKI等数据库,以“E2F,放疗敏感性,辐射敏感性”等为关键词,检索1990-12-2017-05的中英文文献,共检索到英文文献1 560篇,中文文献634篇.纳入标准:(1)E2F的结构其对细胞周期,细胞凋亡,DNA损伤调控的相关研究;(2)肿瘤细胞辐射敏感性影响因素的临床、基础研究;(3)E2F基因与肿瘤放射敏感性关系的基础研究.排除标准:(1)讨论与辐射敏感性因素关系不紧密的研究;(2)探究不与E2F基因相互作用的基因和细胞因子的研究.符合分析的文献126篇,72篇纳入分析.结果 E2F基因通过PRb/E2F通路调控G1/S期转变,进而调控细胞周期进程.细胞DNA损伤后,E2F1通过p53依赖型和非p53依赖型方式诱导细胞凋亡,成为肿瘤放射治疗的潜在靶点.结论 探究E2F基因与肿瘤放射敏感性的关系将可能成为未来提高肿瘤放射敏感性的重要思路.     

低氧诱导因子-1与细胞凋亡关系的研究进展

目的:总结低氧诱导因子-1(HIF-1)与细胞凋亡之间关系的研究现状, 探讨HIF-1在肿瘤等疾病治疗中的应用价值.方法:应用Medline及CNKI期刊全文数据库检索系统,以"低氧诱导因子-1、凋亡和肿瘤"等为关键词,检索2000-2008年的相关文献,共检索到文献378条.纳入标准:1)HIF-1促进细胞凋亡的作用;2)HIF-1抑制细胞凋亡的作用;3)HIF-1影响细胞凋亡的分子机制.根据纳入标准,精选分析36篇文献.结果:HIF-1可以通过调控下游目的基因的表达影响细胞凋亡,在不同条件下发挥促进或抑制细胞凋亡的作用.但是HIF-1在哪种条件下促进或抑制细胞凋亡以及相关的分子机制,目前尚不清楚.结论:虽然HIF-1在细胞凋亡中的作用具有两面性,但两者关系还不太确切,需要进一步的深入研究和综合分析.     

PUMA——非常有前景的肿瘤基因治疗靶点

PUMA(p53上调凋亡调控因子)是2001年发现的Bcl-2蛋白家族中的一员,是p53的下游基因,因为具有强大的促凋亡作用而备受关注.肿瘤组织中的PUMA可被化疗药物诱导而表达增加,同时,PUMA诱导多种肿瘤细胞凋亡,抑制肿瘤细胞增殖,而且,PUMA与有化疗和放疗有协同作用,增加肿瘤细胞对放化疗的敏感性.PUMA的作用与p53状态无关,是非常有前景的肿瘤基因治疗靶点.     

PUMA蛋白结构与功能研究进展

目的:总结PUMA蛋白的结构与功能、促凋亡及其转录调控的作用机制,介绍PUMA蛋白参与线粒体自噬、翻译后磷酸化调控及与之相关的信号通路等最新研究进展。方法:应用PubMed及CNKI期刊等全文数据库检索系统,以"p53上调凋亡调制物(PUMA)、凋亡和肿瘤"等为关键词,检索2002-2012年的相关文献。共检索到英文文献108篇,中文文献12篇。纳入标准:1)PUMA的基本特性;2)PUMA的促凋亡机制;3)PUMA的调控,包括转录调控和翻译后调控;4)PUMA的信号通路及调节因子。根据纳入标准符合分析的文献27篇。结果:PUMA通过BH3结构域的绑定功能发挥促凋亡作用及参与线粒体自噬;PUMA的调控机制主要有转录水平的调控(p53依赖/非依赖途径)及新发现的翻译后磷酸化调控机制;一系列PUMA新的调节因子和信号通路的发现,可以为治疗肿瘤的新抗癌药物提供依据。结论:通过对PUMA蛋白的结构与功能及其调控机制的进一步研究,将为人类肿瘤的诊断和治疗提供新的途径与方法。     

5-FU类药物抗癌新调控机制研究进展

目的:总结国内外对5-氟尿嘧啶(5-FU)类药物抗癌新调控机制的最新进展,为氟尿嘧啶类药物的临床应用以及个体化用药提供依据.方法:应用Medline、PubMed及CNKI数据库检索系统,以“氟尿嘧啶、细胞凋亡、活性氧和DNA错配修复”等为关键词,检索2005-11-2012-01的相关文献,共检索相关文献26篇.纳入标准:1)5-FU类药物诱导肿瘤细胞凋亡作用;2)5-FU类药物通过活性氧(ROS)途径促进细胞凋亡;3)错配修复(MMR)系统及其他分子如P450R、PKC-δ等因素对5-FU类药物抗癌作用的调控.根据纳入标准符合分析的文献26篇.结果:除经典的抗癌作用机制外,5-FU类药物通过死亡受体途径和线粒体途径诱导细胞凋亡,还可以通过增加ROS含量促进细胞凋亡,同时抗癌作用受到MMR系统和P450R等因素的调控.结论:对5-FU类药物的抗癌作用机制及调控因素的研究,有助于为临床指导用药提供理论依据.     

Forkhead家族转录因子FoxM1与肿瘤

目的 随着分子生物学和分子肿瘤学的深入研究,运用肿瘤发生发展中的关键分子做为诊断标志和治疗靶点已成为肿瘤诊治的新趋势.本研究旨在分析Forkhead家族转录因子FoxM1介导肿瘤发生发展的机制及其在分子诊断和靶向干预中的价值.方法 应用PubMed及CNKI期刊全文数据库检索系统,以“FoxM1和肿瘤”为关键词,检索2011-03-2016-02的所有相关文献,共检索到英文文献383篇,中文文献97篇.纳入标准:(1)FoxM1介导肿瘤发生发展的机制;(2)FoxM1与肿瘤分子诊断及靶向干预.根据纳入标准,符合分析的文献44篇.结果 FoxM1通过调控细胞周期G1/S和G2/M期促转化分子Skp2、Cksl、C myc和细胞周期调节分子Cdc25A、Cdc25B、Cyclin D1、p27kip1和p21cip1等表达,影响细胞有丝分裂、细胞周期、DNA损伤修复、细胞增殖与分化等生物学过程.FoxM1过表达导致细胞异常增殖、新生血管形成、上皮间质转化、维持干细胞特性、代谢异常和细胞逃逸衰老等生物学表征,促进细胞恶性转化,参与肿瘤发生发展.FoxM1还可调节多种肿瘤细胞对药物敏感性与耐药性.基于FoxM1的恶性肿瘤诊断系统对多种早期癌症的诊断具有良好价值.以FoxM1为靶点的抗肿瘤化合物通过抑制肿瘤细胞中过度表达的FoxM1成为临床治疗的潜在的新策略.结论 FoxM1过表达促进肿瘤发生发展,检测FoxM1分子有助于肿瘤早期识别,抑制FoxM1可以靶向干预肿瘤的发生发展,FoxM1是肿瘤诊疗的潜在靶标.     

MEKK1在肿瘤MAPK信号传导通路中作用的研究进展

目的:总结国内外关于MEKK1在肿瘤MAPK信号通路中的调控作用,及其对肿瘤转移、细胞迁移和运动影响的研究进展.方法:应用Medline及CNKI期刊全文数据库检索系统,以"MEKK1、MAPK信号转导和肿瘤"为关键词,检索1992-01-2008-01的相关文献,共检索到英文文献4046篇和中文文献2篇.纳入标准:1)MEKK1的来源和分子结构特征;2)MEKK1与肿瘤相关的MAPK信号通路及其他信号通路的关系;3)MEKK1与AP1的关系;4)MEKK1与肿瘤细胞凋亡的关系;5)MEKK1与肿瘤细胞迁移和运动的关系.根据纳入标准,精选55篇文献,最后纳入分析21篇文献.结果:MEKK1是MAPK信号传导通路中的重要结点,也是MAPK通路与其他信号通路的结点.MEKK1具有广泛的生物学功能,如调控NFκB和AP1,影响细胞的存活和凋亡,并且与肿瘤细胞的侵袭、迁移和运动密切相关.结论:MEKK1是抗肿瘤药物研究的潜在靶点,虽然目前还没有MEKK1的抑制剂上市,但可通过研究疾病状态下与MEKK1过表达有关的细胞功能来开发MEKK1抑制剂.     

葡萄糖调节蛋白78与肿瘤耐药关系的研究进展

目的:总结葡萄糖调节蛋白78(glu-cose regulated protein78,GRP78)与肿瘤细胞对化疗药物耐药的关系.方法:以葡萄糖调节蛋白78、肿瘤和耐药为关键词,运用万方数据库、维普数据库、CNKI、EMCC和PubMed检索系统,检索2003～2008年发表的文献,共收集文献55篇,仔细阅读全文,排除重复或类似的研究文献,选取具有代表性的文献,最终纳入分析27篇.结果:GRP78通过多种机制使肿瘤细胞对化疗药物产生耐药.它可以抑制细胞内DNA合成的关键酶之一--拓扑异构酶Ⅱ的表达,细胞内拓扑异构酶Ⅱ的水平直接影响到拓扑异构酶Ⅱ押制剂的化疗效果;可以与Caspase-7和Caspase-12形成复合物,抑制Caspase-7对Caspase-12的激活,从而抑制化疗药物诱导的内质网凋亡途径;并可以通过抑制CHOP即生长停滞及DNA损伤基因(GADD153)的表达,从而抑制与CHOP相关的细胞凋亡.结论:GRP78与肿瘤耐药存在密切关系,对GRP78与肿瘤耐药关系的研究可以丰富对肿瘤耐药机制的认识,为肿瘤化疗提供新的思路.目前针对GRP78治疗的研究正在进行,GRP78可能成为肿瘤化疗的新靶点.     

乳腺癌TGF-β信号通路相关转录因子研究进展

目的 总结与转化生长因子β(transforming growth factor-β,TGF-β)信号通路相关的转录因子在乳腺癌发生发展过程中的作用,分析它们与TGF-β信号通路之间的网络调控机制.方法 应用PubMed及CNKI期刊全文数据库检索系统,以“乳腺癌、转录因子和TGF-β”等为关键词,检索2011-01-01-2015-12 31的相关文献.纳入标准:(1)乳腺癌侵袭转移;(2)转录因子与TGF-β信号通路存在联系.剔除标准:(1)未阐明转录因子与TGF-β信号通路作用的具体机制;(2)实验设计不严谨.符合纳入标准的英文文献146篇,中文文献35篇,根据剔除标准剔除英文文献50篇,中文文献34篇,最后纳入分析文献88篇.结果 TGF-β信号通路是一条极为重要的细胞内信号转导途径,能调控细胞增殖、分化、迁移、粘附及凋亡等生理活动.在乳腺癌中,TGF-β信号通路起着双重作用,即在肿瘤发生的早期阶段,TGF-β信号通路起着一种预防性或肿瘤抑制的作用,但随着肿瘤的发展,TGF-β能够通过影响肿瘤微环境、增强侵袭性及抑制免疫细胞功能来促进肿瘤细胞的转移.多个转录因子c-Myc、p53、C/EBPβ、14-3-3ξ、Blimp-1、Oct-4和Nanog、Foxq1、TBX3、FOXM1、GATA3、HOXB9、Six1、Pokemon、Snail、Slug和SOX4已证实与TGF-β信号通路发生相互作用,共同参与调控乳腺癌发生发展过程.结论 乳腺癌发生过程中转录因子与TGF-β信号通路形成复杂的调控网络,对乳腺癌的进程起着双向调节作用.     

MTDH与肿瘤关系的研究进展

目的:总结异黏蛋白(MTDH)的功能及其作用的分子机制,探讨MTDH与肿瘤的关系。方法:应用Medline、PubMed及CNKI期刊全文数据库检索系统,以"MT-DHt、umor"等为检索词,检索2005-2010年相关文献29条。纳入标准:1)MTDH的功能;2)MTDH作用机制;3)MTDH与肿瘤的关系。根据纳入标准,符合分析的文献18篇。结果:MTDH基因在肿瘤进展中起着重要的作用,包括促进肿瘤细胞增殖、侵袭和转移、避免凋亡及促使肿瘤细胞对化疗药物产生耐药。MTDH通过激活NF-κB、PI3K/AKT、MAPK与wnt/-βcatenin信号通路来促进肿瘤的发生发展。结论:深入研究MTDH在恶性肿瘤中的表达及功能有助于理解肿瘤发生发展的分子机制。MTDH基因有望成为治疗肿瘤的有效靶点。     

Nitrosation by alkyl nitrites. Catalysis by inorganic salts

Isobutyl nitrite is an effective nitrosating agent at acidic, neutral and basic pH in the presence of species arising from phosphate ion. The reaction is first-order in isobutyl nitrite and amine. In the reaction of isobutyl nitrite with sulfanilamide, the pH dependence reflects the change in concentration of the various protonated forms of phosphate, with H3PO4 and H2PO4- most strongly affecting the rate. In the reaction of isobutyl nitrite with dipropylamine, the pH dependence also reflects the change in the concentration of unprotonated amine.     

Chemoprevention by S-adenosyl-L-methionine of rat liver carcinogenesis initiated by 1,2-dimethylhydrazine and promoted by orotic acid

Chemoprevention of liver carcinogenesis by S-adenosyl-Lmethionine(SAM) was studied in F344 male rats. The rats were given 1,2-dimethylhydrazine(1,ZDMH) 2 HCl (100 mg/kg, i.p.) 18 h after two-thirds hepatectomy.One week later they were fed a semisynthetic basal diet containing1% orotic acid (OA) for 29 weeks. At this time the rats weretransferred to the basal semisynthetic diet and were killed3 weeks later. SAM treatment (384 µmol/kg/ day, im.),was started 1 week after 1,2-DMH and was continued up to theend of the experiment. Controls received solvent alone. SAMexerted an inhibitory effect on the induction of preneoplasticand neoplastic lesions. For example, nodules with diametersof 1-2 and 2-6 mm exhibited a decrease in both incidence andnumber per liver, while no such inhibitory effect was seen inthe category of larger nodules. Furthermore, hepatocellularcarcinoma (HCC) also exhibited a decrease in the SAM-treatedgroup. The numberniver and incidence were 0.04 and 4.8% respectivelyin the SAM-treated group, compared to 0.38 and 37.8% in thecontrol group. Microscopic examination showed the presence ofwell-differentiated carcinomas and atypical nodules in controlrats, while only one small, well-differentiated tumor and onenodule with patterns of initial transformation were seen inSAM-treated rats. No patchy staining of glutathione-S-transferase,indicative of remodeling, was observed in nodules of both SAM-treatedand control rats. Nodules and HCCs developing in SAM-treatedrats exhibited a relatively high number of apoptotic bodies.Apoptotic bodies count showed 2.8-and 1.8-fold increases innodules and HCCs of SAM-treated rats with respect to controls.These results indicate that SAM exerts a chemopreventive effecton hepatocarcinogenesis induced by the OA model. SAM seems tobe more effective in inhibiting nodule to HCC progression thanon the growth of nodule per se. The inhibitory effect is associatedwith an increase in cell loss by apoptosis in nodules and HCC.     

Post-treatment skin reactions reported by cancer patients differ by race, not by treatment or expectations

Cancer patients may experience skin problems while undergoing chemotherapy and radiation therapy. Frequency of skin reactions may be influenced by skin pigmentation and psychological factors. A Symptom Inventory completed by 656 cancer patients nationwide before and after chemotherapy, radiation therapy, or chemotherapy plus radiation therapy was analysed to determine if treatment type, race (Black vs White), and pretreatment expectations influenced post-treatment skin reactions. Subsequent analysis of a local Symptom Inventory completed weekly for 5 weeks by 308 patients receiving radiation therapy examined severity of reported skin reactions. Significantly more patients receiving radiation therapy had stronger expectations of skin problems (62%) than patients receiving chemotherapy (40%, P=0.001) or chemotherapy plus radiation therapy (45%, P=0.003). Overall, expectations did not correlate with patient reported post-treatment skin problems in white (r=0.014, P=0.781) or black (r=0.021, P=0.936) patients. Although no significant difference was found between black and white patients in their pretreatment expectations of skin problems (P=0.32), black patients (10 out of 18, 56%) reported more skin problems than white patients (90 out of 393, 23%, P=0.001). Similarly, the local study showed that significantly more black patients (1 out of 5, 20%) reported severe skin reactions at the treatment site than white patients (12 out of 161, 8%). A direct correlation was observed between severity of skin problems and pain at the treatment site (r=0.541, P<0.001). Total radiation exposure did not significantly correlate with the report of skin problems at the treatment site for white or black patients. Overall, black patients reported more severe post-treatment skin problems than white patients. Our results suggest that symptom management for post-treatment skin reactions in cancer patients receiving radiation treatment could differ depending on their racial background.     

Stimulation of glycolysis by placental polypeptides and inhibition by duramycin

Placental polypeptides present in crude preparations of transforming growth factors stimulate glycolysis when added to quiescent 3T3 cells, normal rat kidney, and chick embryo fibroblasts. The stimulation was apparent over a time period of at least 90 min and was seen at glucose concentrations ranging from 1 to 30 mM. Duramycin, an antibiotic isolated from Streptomyces cinnamomeus, inhibits the polypeptide-stimulated and nonstimulated glycolysis of intact cells, since it permeabilizes cells to Pi and nucleotides. However, duramycin also inhibits the Na+-K+-ATPase as well as the ouabain-insensitive Mg2+-ATPase of plasma membranes. Duramycin has no effect on glycolysis catalyzed by cell-free extracts of Ehrlich ascites tumor cells in the presence of mitochondrial ATPase but partially inhibits glycolysis when ADP and Pi are generated by ATPases of plasma membrane preparations.     

Enhancement by methionine enkephalin of colon carcinogenesis induced by azoxymethane

The effect of the opioid receptor agonist methionine enkephalin (Met-enkephalin) and the opioid receptor antagonist naloxone on colonic carcinogenesis induced by azoxymethane was investigated in Wistar rats. Rats received ten weekly injections of 7.4 mg/kg of body weight of azoxymethane and injections of Met-enkephalin (50 micrograms/kg of body weight), naloxone (2 mg/kg of body weight), or Met-enkephalin (50 micrograms/kg of body weight) plus naloxone (2 mg/kg of body weight) once every 2 days. In wk 40, the group treated with Met-enkephalin had a significantly increased incidence of colonic tumors. A combination of Met-enkephalin and naloxone attenuated the enhancing effect by Met-enkephalin on the development of colonic tumors. Administration of naloxone alone had no influence on colonic tumorigenesis. During and after administration of the carcinogen, the bromodeoxyuridine-labeling indices of the colon mucosa and/or cancers were significantly increased in rats treated with Met-enkephalin. However, a combination of Met-enkephalin and naloxone significantly decreased the labeling indices of the colon mucosa and/or cancers. These findings indicate that Met-enkephalin enhanced colon carcinogenesis and that naloxone attenuated this enhancement. Because naloxone is an opioid receptor antagonist, these findings also indicate that the enhancing effect of Met-enkephalin on colon carcinogenesis may be mediated through opioid receptors.     

Production of plasminogen activator by cells transformed by herpesviruses.

Plasminogen activator is produced by hamster cells transformed by human herpesviruses. These cell lines have previously been shown to be oncogenic when injected s.c. into newborn syngeneic hamsters. Lysis of fibrin overlays by these cell lines was plasminogen dependent. Normal hamster embryo fibroblasts and a hamster cell line transformed by PARA-7 (an adenovirus-SV 40 hybrid) failed to produced lysis. In separate experiments fibrin overlay of lytically infected secondary rabbit kidney cells did not show induction of this activity during the normal course of productive infection. The human cell line TE-85 clone F-5, a clonal cell line from a human osteogenic sarcoma, failed to produce plasminogen activator, but two separate clones of these cells that were morphologically transformed after exposure to UV-inactivated herpes simplex virus type 2 produced rapid lysis of the fibrin overlay. Clonal variation was observed in herpes simplex virus types 1 and 2-transformed hamster lines and is under investigation. It is suggested that plasminogen activator detection may serve as a convenient assay system for transformation of normal cells by herpesviruses.     

Fibromatosis: benign by name but not necessarily by nature

Aggressive fibromatoses, also known as desmoid tumours, are rare fibrous tissue proliferations with a tendency for slow, local infiltrative growth. There is an association with Gardner's syndrome and familial adenomatous polyposis. Histologically they are fairly bland with no abnormal mitoses or necrosis. They do not metastasize, but can cause significant morbidity through their locally destructive effects. Magnetic resonance imaging is the method of choice for diagnosis, pre-treatment planning and post-treatment follow-up. Surgical excision with a wide margin is the treatment of choice. However, there is a tendency for local recurrence and repeated excision may result in a poor functional or cosmetic outcome. Radiotherapy is used to reduce local recurrence rates after excision and is also used to treat inoperable tumours. Long-lasting remissions can be obtained. Treatment is now planned using modern three-dimensional conformal techniques, similar to those used in soft tissue sarcoma management. There is no definite dose-response relationship, but doses of 50-60 Gy in 1.8-2 Gy fractions are recommended. Systemic therapy has been used for lesions not controlled by surgery or radiotherapy, or less commonly, as a primary treatment. Tamoxifen and non-steroidal anti-inflammatory agents are used most often as they are relatively non-toxic, but there is limited experience with cytotoxic chemotherapy and biological agents. There are no randomised trials to help guide the management of this locally aggressive 'benign' tumour and treatment decisions are best made by the local soft tissue sarcoma multidisciplinary team.     

Enhancement by ethyl alcohol of experimental hepatocarcinogenesis induced by N-nitrosomorpholine

The effects of ethyl alcohol (EtOH) during or after treatment with N-nitrosomorpholine (NNM) on hepatocarcinogenesis, ornithine decarboxylase (ODC) activity and the labeling index of the liver were investigated in male Sprague-Dawley rats. Rats were given drinking water containing NNM for 8 weeks and received i.p. injections of 1 g EtOH/kg body weight every other day during or after treatment with NNM. Pre-neoplastic and neoplastic lesions staining positively for glutathione-S-transferase, placental type (GST-P), were examined immunohistochemically. At the end of experiment at week 16, administration of EtOH after NNM treatment had no significant effect on the number and size of GST-P-positive hepatic lesions, whereas administration of EtOH during NNM treatment significantly increased the number and percentage area but not the mean area of GST-P-positive hepatic lesions. EtOH caused significant increases in the ODC activity of the liver and in the labeling indices of enzyme-altered lesions and the adjacent hepatocytes after the cessation of EtOH administration but not during EtOH treatment. Our findings indicate that EtOH enhances hepatocarcinogenesis and suggest that this effect may be closely related to the increases in ODC activity and cell proliferation in enzyme-altered lesions and the adjacent liver after EtOH treatment. Int. J. Cancer 71: 1045-1048, 1997. © 1997 Wiley-Liss Inc.