WNT信号通路与肿瘤

WNT信号通路在肿瘤发生中有重要意义,它调节细胞生长、迁移和分化。由于它在众多人类肿瘤的发生中广泛活化,近年来这条通路在肿瘤研究方面受到很多关注。本文将介绍该通路与肿瘤发生的关系,以及目前该通路的研究在抗肿瘤治疗中的应用前景。     

Hippo信号通路与肿瘤发生的研究进展

Hippo信号通路是近年来研究发现的能够协调细胞增殖、细胞死亡和细胞分化,调控组织生长的一个高度保守的生长控制信号通路,其核心成分是Yap/Taz等转录调控因子。该信号通路的组成原件包括Mst1/2、Sal、Last1/2和Mob1,这些蛋白具有肿瘤抑制功能,Yap/Taz具有致瘤作用。因此该信号通路与控制器官大小,癌症的发生有着密切的关系。本文主要介绍Hippo信号通路在器官大小控制和癌症发生中的作用。     

TGFβ信号通路与肿瘤

TGFβ影响细胞的增殖和分化 ,在肿瘤发生与进展、细胞外基质形成和免疫调节等过程中发挥重要作用。TGFβ通过胞膜上的受体和胞内 Sm ads家族向核内传递信号 ,调控靶基因。肿瘤中的 TGFβ信号通路异常有其多样性和复杂性。近年来 ,TGFβ信号通路的研究取得了突破性进展 ,本文综述了恶性肿瘤中的 TGFβ信号通路的异常。     

Hippo信号通路与肿瘤发生相关性研究进展

Hippo信号通路是新发现的生长控制信号通路,能够限制细胞的生长增殖,诱导细胞凋亡,信号通路不能激活或者作用下调有利于肿瘤的发生。信号通路的组成成分中包括多种抑癌基因和一种候选癌基因,其中候选癌基因YAP在多种类型的人类肿瘤中表达异常增加,而RASFF、MER等抑癌基因在一些人类肿瘤细胞系中突变失活或缺失。     

TGF-β信号通路与造血系统肿瘤

转化生长因子β(TGF-β)是造血细胞生长的负调控因子,TGF-β/SMAD信号途径在造血系统恶性肿瘤的发生中起到重要的作用,TGF-β表达及受体或受体后水平缺陷都可导致造血细胞的恶性增殖。深入研究该信号通路对于探寻造血系统恶性肿瘤的发病机制及开发以该通路环节为靶点的靶向治疗具有积极意义。     

Notch信号通路与肝癌的研究进展

Notch信号通路是一种高度保守的信号通路,在调节细胞分化、增殖和凋亡等一系列生理病理过程中都起着关键性的作用。Notch信号在肝癌中频繁发生异常表达及激活突变,其通过多种机制促进肝癌的发生发展,且与肝癌的侵袭、转移和预后密切相关。因此,Notch信号可作为肝癌治疗的一个靶标,为肝癌的治疗提供新的方向和机遇。     

BMPs信号通路与乳腺癌发生、发展的研究进展

BMPs属于转化生长因子-β超家族,在介导细胞增殖、凋亡、迁移、分化等方面发挥了重要作用。BMPs异常表达、紊乱在肿瘤发生、发展过程中的作用为目前的一大研究热点,本文着重探讨了BMPs信号通路的紊乱及其甲基化在乳腺癌变过程中发挥的作用。     

胰岛素信号通路与动脉粥样硬化

动脉粥样硬化(atherosclerosis,AS)性血管病变是导致2型糖尿病患者致残、致死的主要原因之一.最终大部分糖尿病患者死于AS相关并发症.胰岛素分泌不足和胰岛素抵抗是2型糖尿病的主要病理生理特征.胰岛素受体广泛分布于全身各个器官和组织,胰岛素受体信号通路的激活对维持细胞正常生理功能有重要的作用.     

Wnt与MAPK信号通路在肿瘤发生中的串话

Wnt和MAPK信号通路在生物进化过程中高度保守,参与调控胚胎发育和细胞增殖、分化及凋亡等.Wnt和MAPK信号通路调控失常可导致胚胎发育异常和肿瘤形成.近年来发现这两条信号通路在肿瘤发生发展中存在着大量串话(crosstalk),彼此之间相互调节,共同发挥促癌或抑癌作用,因此,更好地了解两条通路是如何在肿瘤形成中发生交叉对话对于将来肿瘤治疗非常有价值.     

唇腭裂相关基因的关键信号通路

唇腭裂是一种常见的出生缺陷,其发生的分子机制是近年来的研究热点。目前已有超过100个唇腭裂相关基因被发现,但这些基因的致病机制还有待阐明。基因携带的遗传信息通过信号通路来影响表型,信号通路的顺利传递是机体正常发育的必要条件。唇腭裂的形成过程中亦有信号通路的异常表达。一系列信号因子参与基因表达的调控,它们之间又相互作用,构成信号通路及复杂精细的信号调控网络,共同参与指导细胞活动及组织形成。本文就目前研究较多的与唇腭裂相关的几个重要信号通路进行概括,综述了唇腭裂发展过程中的重要分子机制,以期为唇腭裂的病因学及遗传学研究提供参考。     

The combined status of ATM and p53 link tumor development with therapeutic response

While the contribution of specific tumor suppressor networks to cancer development has been the subject of considerable recent study, it remains unclear how alterations in these networks are integrated to influence the response of tumors to anti-cancer treatments. Here, we show that mechanisms commonly used by tumors to bypass early neoplastic checkpoints ultimately determine chemotherapeutic response and generate tumor-specific vulnerabilities that can be exploited with targeted therapies. Specifically, evaluation of the combined status of ATM and p53, two commonly mutated tumor suppressor genes, can help to predict the clinical response to genotoxic chemotherapies. We show that in p53-deficient settings, suppression of ATM dramatically sensitizes tumors to DNA-damaging chemotherapy, whereas, conversely, in the presence of functional p53, suppression of ATM or its downstream target Chk2 actually protects tumors from being killed by genotoxic agents. Furthermore, ATM-deficient cancer cells display strong nononcogene addiction to DNA-PKcs for survival after DNA damage, such that suppression of DNA-PKcs in vivo resensitizes inherently chemoresistant ATM-deficient tumors to genotoxic chemotherapy. Thus, the specific set of alterations induced during tumor development plays a dominant role in determining both the tumor response to conventional chemotherapy and specific susceptibilities to targeted therapies in a given malignancy.     

Two ATM variants and breast cancer risk

The ATM gene is mutated in ataxia-telangiectasia (AT). Heterozygote female relatives of AT cases have a 2-7fold increased risk of breast cancer. We previously reported high risks of breast cancer associated with certain ATM variants. To estimate the risks more precisely, we have examined two ATM variants, c.1066-6T>G (IVS10-6T>G) and c.4258C>T (p.Leu1420Phe), in additional cases and controls from the same Australian cohorts previously used to estimate the risk of breast cancer associated with c.1066-6T>G. A total of 775 and 84 population-based controls were genotyped for the c.1066-6T>G and c.4258C>T ATM variants respectively, as were index cases from 378 and 373 non-BRCA1/2 breast cancer families. Penetrance was estimated by Bayes factor analysis. The allele frequencies of ATM c.1066-6T>G and c.4258C>T estimated from controls were 0.005 (95% CI=0.002 to 0.009) and 0.012 (95% CI=0.001 to 0.042), respectively. We identified three new breast cancer families with c.1066-6T>G, and seven families with c.4258C>T. Combining with the two c.1066-6T>G families previously reported, the estimated penetrance to age 70 of c.1066-6T>G was 17.2% (95% CI=4.7% to 37.5%). For c.4258C>T, the estimated average penetrance was 4.8% (95% CI 1.7% to 10.1%). In conclusion, we found no evidence that the ATM c.4258C>T variant increases breast cancer risk, and little evidence that c.1066-6T>G confers an elevated risk. Analysis of additional families will be necessary to define more precisely the risk, if any, associated with c.1066-6T>G.     

Histopathological features of breast cancer in carriers of ATM gene variants

AIMS: Germline variants in the ataxia telangiectasia mutated (ATM) gene have been implicated in increased breast cancer risk. The aim of this study was to determine whether the histopathology of breast cancers occurring in ATM variant carriers is distinctive or resembles the described BRCA1 mutation-associated phenotype. METHODS: The histopathological features of breast cancers occurring in ATM variant carriers from multiple-case breast cancer families were compared with matched controls. The test group included 21 cases of in situ and/or invasive cancer from carriers of either the IVS10-6T-->G, 2424V-->G or 1420L-->F ATM variants in the absence of BRCA1 or BRCA2 mutations. An additional four invasive cancers from carriers of a pathogenic BRCA1 mutation in the context of a familial ATM variant were also examined. RESULTS: The histopathology of breast cancers in ATM variant-only carriers was not significantly different from controls and known features of BRCA1 mutation-associated cancer were rarely seen. In contrast, these features were prominent in the small group of cases with a pathogenic BRCA1 mutation. CONCLUSIONS: Breast cancer occurring in carriers of ATM variants is not associated with distinctive histopathological features and does not resemble the tumour phenotype commonly observed in BRCA1 mutation carriers.     

Ataxia-telangiectasia, cancer and the pathobiology of the ATM gene

Ataxia-telangiectasia (A-T) is a pleiotropic inherited disease characterized by neurodegeneration, cancer, immunodeficiencies, radiation sensitivity, and genetic instability. Although A-T homozygotes are rare, the A-T gene may play a role in sporadic breast cancer and leukemia. ATM, the gene responsible for A-T, is homologous to several cell cycle checkpoint genes from other organisms. ATM is thought to play a crucial role in a signal transduction network that modulates cell cycle checkpoints, genetic recombination, apoptosis, and other cellular responses to DNA damage. New insights into the pathobiology of A-T have been provided by the creation of Atm-/- mice and by in vitro studies of ATM function. Analyses of ATM mutations in A-T patients and in sporadic tumors suggest the existence of two classes of ATM mutation: null mutations that lead to A-T and dominant negative missense mutations that may predispose to cancer in the heterozygous state.     

肿瘤中雌激素信号转导通路的研究进展

雌激素（estrogen,E₂）可通过特异性结合并激活其受体传递信号,广泛调控机体的各种功能,如生殖功能、骨骼及其它组织的分化和维持等。雌激素受体属于核受体超家族,有3个亚类即雌激素受体α（estrogenreceptorα,ERα）、ERβ和最近发现的G蛋白偶联受体——GPR（G protein-coupled receptor）30/GPER（G protein-coupled estrogen receptor）。典型的ER作     

中国人共济失调毛细血管扩张症ATM基因突变研究

目的　探讨中国人共济失调毛细血管扩张症(ataxia- telangiectasia,AT) ATM基因的突变特点。方法　应用聚合酶链反应、逆转录-聚合酶链反应、聚丙烯酰胺凝胶电泳结合DNA序列分析方法对2例中国人临床诊断AT的患者ATM基因进行突变的筛选与检测。结果　在1例患者中发现第11外显子的1346 (G>C)的错义突变,为一种纯合突变;在另1例患者中发现第6外显子的6 10 (G>T)的无义突变和第4 7外显子的6 6 79(C>T)的错义突变,为一种复合性杂合突变。突变位点均位于ATM基因功能域。结论　在2例中国人AT患者中发现了3种新的ATM基因突变。     

ATM germline mutations in Spanish early-onset breast cancer patients negative for BRCA1/BRCA2 mutations

Heterozygous carriers of ATM (ataxia telangiectasia mutated gene) mutations have increased risk of breast cancer (BC). We have estimated the prevalence of mutations in the ATM gene among Spanish patients with early-onset BC. Forty-three patients diagnosed with BC before the age of 46 years, and negative for BRCA1 and BRCA2 mutations, were analysed for the presence of ATM mutations. A total of 34 ATM sequence variants were detected: 1 deleterious mutation, 10 unclassified variants and 23 polymorphisms. One patient (2.3%) carried the ATM deleterious mutation (3802delG that causes ataxia telangiectasia in the homozygous state) and 13 patients carried the 10 ATM unclassified variants. The truncating mutation 3802delG and eight of the rare variants were not detected in a control group of 150 individuals. Different bioinformatic sequence analysis tools were used to evaluate the effects of the unclassified ATM changes on RNA splicing and function protein. This in silico analysis predicted that the missense variants 7653 T>C and 8156 G>A could alter the splicing by disrupting an exonic splicing enhancer motif and the 3763 T>G, 6314 G>C, and 8156 G>A variants would affect the ATM protein function. These are the initial results concerning the prevalence of germline mutations in the ATM gene among BC cases in a Spanish population, and they suggest that ATM mutations can confer increased susceptibility to early-onset BC.     

TLR信号通路在慢性炎症性关节炎中的作用

Toll样受体（TCR）可以识别致病微生物的病原体相关分子模式,激活下游区的信号转导通路,参与各种固有免疫和适应性免疫应答。最近,已有报道,慢性炎症性关节炎的滑膜组织高表达TLR,导致滑膜炎性介质持续存在,因而了解TLR信号通路有利于深入研究慢性炎症性关节炎的发病机制,并为其治疗提供特异性的靶位点。     

The impact of microRNAs on myeloid-derived suppressor cells in cancer

Inflammation promotes cancer development. To a large extent, this can be attributed to the recruitment of myeloid-derived suppressor cells (MDSCs) to tumors. These cells are known for establishing an immunosuppressive tumor microenvironment by suppressing T cell activities. However, MDSCs also promote metastasis and angiogenesis. Critically, as small non-coding RNAs that regulate gene expression, microRNAs (miRNAs) control MDSC activities. In this review, we discuss how miRNA networks regulate key MDSC signaling pathways, how they shape MDSC development, differentiation and activation, and how this impacts tumor development. By targeting the expression of miRNAs in MDSCs, we can alter their main signaling pathways. In turn, this can compromise their ability to promote multiple hallmarks of cancer. Therefore, this may represent a new powerful strategy for cancer immunotherapy.