腺苷酸活化蛋白激酶:肿瘤治疗新靶点

腺苷酸活化蛋白激酶(AMP-activated protein kinase,AMPK)是真核细胞内发现的一类与细胞能量代谢有关激酶家族中的一员,被称之为"能量感应器".当细胞内AMP/ATP值升高时,AMPK被激活.研究发现,在肿瘤细胞中,活化的AMPK可协同相关抑癌因子调节细胞周期、细胞凋亡以及蛋白质合成,最终影响细胞的增殖.因而,AMPK可以通过感应细胞能量水平的变化来调节细胞增殖.这给肿瘤治疗提供了一定的启示,即以肿瘤细胞能量代谢特点而探寻抑制肿瘤细胞增殖的途径.     

腺苷酸活化蛋白激酶与阿尔茨海默病

腺苷酸活化蛋白激酶(AMPK)是调节细胞能量平衡、葡萄糖和脂质代谢的关键酶,可能与阿尔茨海默氏病(AD)的发病机制相关。AMPK激活可以通过调节AD神经元胆固醇和鞘磷脂的水平来减少淀粉样蛋白(Aβ)的生成,AMPK也可以改善AD患者大脑紊乱的能量代谢。AMPK对tau蛋白磷酸化的调节作用有相反结论,机制还不明确。此外,AMPK的激活可以抑制mTOR信号通路来促进细胞自噬和溶酶体降解Aβ。越来越多的研究表明,AMPK是阻止代谢性应激的神经保护因子,是治疗AD的潜在靶点。     

以血管为靶向的肿瘤显像和治疗的研究进展

血管是肿瘤生长的重要条件，是侵袭、转移的重要途径。与直接以肿瘤细胞为靶点相比，以血管内皮细胞上整合素和酪氨酸酶为靶点的显像和治疗有其独特之处。放射性核素显像及PET可以评价血管抑制剂治疗肿瘤的效果，并对治疗中的患者进行监测。目前以肿瘤血管为靶点的药物主要分为三个方面：①抑制血管内皮细胞生长；②抑制这些血管生成因子的活性；③防止细胞外基质降解。此外，纳米材料在该领域的运用，使有效并选择性地将基因或药物运输到肿瘤血管成为可能。     

腺苷酸活化蛋白激酶与骨骼肌蛋白质降解*☆

背景：机体运动时骨骼肌收缩,ATP被大量消耗,产生大量腺苷一磷酸,导致腺苷酸活化蛋白激酶的激活。 目的：综述不同运动过程中腺苷酸活化蛋白激酶活性的变化,以及腺苷酸活化蛋白激酶对骨骼肌蛋白质降解的研究成果。 方法：检索中国期刊网、维普期刊数据库、www.ncbi.nlm.nih.gov/pubmed和http://highwire.stanford.edu/网站与腺苷酸活化蛋白激酶、运动、蛋白质降解研究相关的文章。并对腺苷酸活化蛋白激酶的结构与作用,不同运动过程中腺苷酸活化蛋白激酶活性的变化,以及腺苷酸活化蛋白激酶升高对骨骼肌蛋白质降解的内容进行分析综述。 结果与结论：共纳入相关文献35篇。本文综述了腺苷酸活化蛋白激酶的结构、作用的研究进展;在抗阻运动和中到大强度的周期运动中,腺苷酸活化蛋白激酶活性都可能升高,而在小强度周期运动过程中腺苷酸活化蛋白激酶活性可能不升高;腺苷酸活化蛋白激酶的活化可能对骨骼肌蛋白质的降解有促进作用。     

肿瘤干细胞与肿瘤靶向治疗

肿瘤干细胞(TSC)理论认为,肿瘤内部存在的一小部分具有干细胞特性的细胞,是肿瘤形成、生长、转移和复发的根源,只有靶向肿瘤干细胞的治疗才能使恶性肿瘤治愈.目前肿瘤的治疗只能杀死大部分已分化的肿瘤细胞,不能杀死肿瘤干细胞,造成了肿瘤治疗效果的不理想.扰乱维持肿瘤干细胞自我更新的信号通路和微环境;或诱导肿瘤干细胞的分化;或针对肿瘤干细胞所表达的区别于正常干细胞的表面标志的靶向治疗都是可行的策略.     

恶性肿瘤的分子靶点检测和靶向治疗

随着肿瘤分子生物学的发展,分子靶向治疗作为肿瘤治疗的新手段逐渐成为热点.靶向治疗具有特异性强、疗效明显、对正常组织损伤较小等优点.该文对常用的分子靶向治疗药物及其靶点检测做一综述.     

肿瘤治疗的新靶点Ets基因家族

Ets基因家族作为最大的信号依赖转录调控因子家族之一,在细胞发育分化、增殖凋亡、血细胞生成、血管发生及组织重建中发挥着重要作用。Ets基因的异常可导致细胞的恶性转化和肿瘤的发生发展,因此它们有可能成为肿瘤基因治疗的潜在分子靶点。     

做好靶向病理诊断夯实肿瘤靶向治疗的基础

近30年随着肿瘤分子生物学研究的不断深入,特别是对癌基因和肿瘤抑制基因、生长因子和生长因子受体、调解肿瘤细胞生长和分化及凋亡的信号分子、肿瘤血管形成以及大量非随机出现在各种肿瘤的染色体易位等方面的研究成果地不断涌现,已为针对这些关键分子靶点开展肿瘤靶向治疗奠定了基础。     

靶向药物内照射治疗肿瘤的现状与未来

本文从发展内照射治疗药物的必要性出发，提出了分子核医学靶向治疗中值得关注的３类靶向抑癌药物，即用放射性核素标记的抗肿瘤抗体，可与肿瘤受体相结合的生物活性肽，以及原癌基因的反义寡核苷酸。结合这３类药物的发展过程，着重阐述了它们的治疗机理和优点；同时也分析了存在的问题及今后发展的趋势     

GPNMB与肿瘤靶向治疗

非转移性黑色素瘤糖蛋白 B(glycoprotein non-metastatic melanoma protein B,GPNMB)是一种高度糖基化的 I 型跨膜糖蛋白,定位于细胞膜或贮存于内涵体及溶酶体中.膜结合型 GPNMB 可被金属蛋白酶如 ADAM 10 裂解,释放出可溶性形式.该蛋白最初被发现于非转移性黑色...     

Mutation of a putative AMPK phosphorylation site abolishes the repressor activity but not the nuclear targeting of the fungal glucose regulator CRE1

In filamentous ascomycetes, glucose repression is mediated by CRE1, a zinc-finger protein related to Mig1p from yeast. Five putative AMPK phosphorylation motifs identified in the glucose repressor from the phytopathogenic fungus Sclerotinia sclerotiorum were mutated in a GFP::CRE1 translational fusion. Complementation experiments in Aspergillus nidulans and fluorescence microscopy analyses showed that mutation of one site (Ser₂₆₆) abolishes the repressor activity of the fusion protein but not its nuclear targeting, suggesting that an AMPK protein kinase may be involved in the function of the fungal glucose repressor. Received: 23 November 1999 / 25 January 2000     

The activation of AMPK in cardiomyocytes at the very early stage of hypoxia relies on an adenine nucleotide-independent mechanism

The energy status of a cell plays a key role in its survival, and the exposure of eukaryotic cells to the hypoxia that accompanies the depletion of intracellular ATP triggers specific systemic adaptive responses. AMP-activated protein kinase (AMPK) has emerged as a key regulator of energy metabolism in the heart and plays a critical role in inducing these responses. However, the specific mechanism responsible for AMPK activation in cardiomyocytes at very early stages of hypoxia remain unclear. The goals of this study were to assess the relative contribution to AMPK activation of phosphorylation by AMPK kinase (AMPKK) and of positive allosterism due to AMP:ATP ratios in the early stages of hypoxia. Our results demonstrated that, compared with normoxic controls, neither intracellular AMP concentrations nor AMP:ATP ratios significantly increased within 1h of hypoxia onset. In contrast, a SAMS peptide phosphorylation assay and an immunoblot analysis revealed significant increases in both AMPK activity and ACC phosphorylation within 5min of hypoxic treatment. Furthermore, exposure of cardiomyocytes to hypoxia significantly increased AMPK phosphorylation within 5min, by 3- to 4-fold compared with controls (P<0.01), while overall levels of AMPKα protein did not differ between aerobic and anoxic cardiomyocytes. We also observed increased AMPKK activity in anoxic cardiomyocytes, through use of an α₃₁₂ substrate. Taken together, our findings demonstrate that in the early stage of hypoxia in cardiomyocytes, increases in AMPK activity occur prior to and independently of increases in AMP concentration or in the AMP:ATP ratio. Instead, under these circumstances, AMPK is primarily activated by phosphorylation of the conserved Thr-172 residue in its activation loop by its upstream kinase AMPKK.     

AMPK与心脏缺血再灌注损伤

腺苷酸活化蛋白激酶（AMPK）作为一种能量调控器,对心脏尤其是当心脏面临缺血性损伤对能量需求显著增加的时候具有重要作用。活化的AMPK能够增加葡萄糖摄取和糖酵解,加速脂肪酸氧化增加心肌组织的能量供应,并能抑制心肌细胞凋亡来保护心肌组织。     

Cell surface antigen and molecular targeting in the treatment of hematologic malignancies

Conventional cytotoxic therapy of hematologic malignancies is often associated with significant morbidity. This morbidity is often due to the lack of specificity for hematopoietic cells. Therefore, the concept of targeted therapy for patients with hematologic malignancies has received attention for many years. The goal of monoclonal antibody therapy is to target specific cell surface antigens on malignant hematopoietic cells, while sparing normal cells and tissues. Currently, monoclonal antibodies are being evaluated for their cytotoxic effects as well as their ability to deliver toxic agents or radiation. Rituximab, a chimeric anti-CD20 antibody, has shown response rates of approximately 50% with minimal toxicity in patients with refractory indolent lymphoma. Campath-1H (anti-CD52) has shown encouraging results in patients previously treated for chronic lymphocytic leukemia, with response rates up to 33%, although with significant toxicity. Anti-CD33 antibodies are being used to deliver cytotoxic agents, such as calicheamicin to patients with acute myeloid leukemia with response rates up to 30%. In addition, anti-CD33 and anti-CD45 antibodies have been used to deliver radiation directly to leukemic cells. (131)I-labeled anti-CD45 antibodies are being studied in combination with conventional preparative regimens in patients receiving bone marrow transplantation. Lastly, the therapeutic agent STI571 (signal transduction inhibitor 571) has demonstrated the capability of targeting specific molecular abnormalities seen in hematologic malignancies. STI571 targets the tyrosine kinase activity of the bcr-abl fusion protein seen in chronic myeloid leukemia. STI571 has induced complete hematologic responses in up to 98% of patients evaluated in clinical trials.     

Adipo/AMPK信号通路的下调参与肥胖型哮喘小鼠的发病

目的探讨Adipo/AMPK信号通路在肥胖型哮喘气道炎性反应及气道高反应中的作用及机制。方法将40只SPF级C57BL/6小鼠随机分为正常体质量组(A)、哮喘组(B)、肥胖组(C)和肥胖哮喘组(D),A组进行普通饲料喂养+0.9%氯化钠溶液致敏激发,B组进行普通饲料喂养+OVA/Al(OH)3致敏激发,C组予以高脂饲料喂养+0.9%氯化钠溶液致敏激发,D组则给予高脂饲料喂养+OVA/Al(OH)_3致敏激发。测定各组小鼠气道阻力,HE染色观察肺组织病理改变,ELISA法检测血清Adipo水平,qRT-PCR法检测肺组织Adipo、AdipoR1及AMPKαmRNA的表达,Western blot法检测肺组织Adipo、AMPKα和p AMPKα蛋白的表达水平。结果 C组和D组小鼠体质量增长明显(P0.01);与A组相比,B组、C组和D组总气道阻力(RL)增高、肺部炎性反应加重,D组增高最显著(P0.05);同时,B组、C组和D组小鼠肺组织Adipo mRNA、AdipoR1 mRNA、Adipo蛋白和p AMPKα蛋白的表达较A组显著降低(P0.05)。结论肥胖型哮喘小鼠气道反应增高、气道炎性反应加重可能与Adipo/AMPK信号通路的下调有关。     

二甲双胍激活MIN6细胞AMPK活性并抑制其胰岛素分泌

目的:观察二甲双胍对MIN6细胞胰岛素分泌和AMPK磷酸化水平的影响,以探讨二甲双胍影响胰岛素分泌的可能机制。方法:将MIN6细胞接种于24孔或6孔细胞培养板,用不同浓度葡萄糖和二甲双胍分别培养1h或20h后收集上清,待测胰岛素;抽提蛋白,检测蛋白磷酸化水平。结果:western blot结果显示20μM二甲双胍培养1h对MIN6细胞内AMPK磷酸化没有影响,培养20h则能增加AMPK磷酸化。MIN6在20μM二甲双胍存在条件下培养20h后,换入含25mmol/L葡萄糖和相同浓度药物的KRB缓冲液孵育1h,测定上清液胰岛素浓度,20μM二甲双胍组胰岛素分泌降低19.5%(P<0.05)。结论:抑制AMPK活性可以促进胰岛素分泌,二甲双胍可能通过激活AMPK活性抑制胰岛素分泌。     

Age-related changes in AMPK activation: Role for AMPK phosphatases and inhibitory phosphorylation by upstream signaling pathways

AMP-activated protein kinase (AMPK) is a fundamental regulator of energy metabolism, stress resistance, and cellular proteostasis. AMPK signaling controls an integrated signaling network which is involved in the regulation of healthspan and lifespan e.g. via FoxO, mTOR/ULK1, CRCT-1/CREB, and SIRT1 signaling pathways. Several studies have demonstrated that the activation capacity of AMPK signaling declines with aging, which impairs the maintenance of efficient cellular homeostasis and enhances the aging process. However, it seems that the aging process affects AMPK activation in a context-dependent manner since occasionally, it can also augment AMPK activation, possibly attributable to the type of insult and tissue homeostasis. Three protein phosphatases, PP1, PP2A, and PP2C, inhibit AMPK activation by dephosphorylating the Thr172 residue of AMPKα, required for AMPK activation. In addition, several upstream signaling pathways can phosphorylate Ser/Thr residues in the β/γ interaction domain of the AMPKα subunit that subsequently blocks the activation of AMPK. These inhibitory pathways include the insulin/AKT, cyclic AMP/PKA, and RAS/MEK/ERK pathways. We will examine the evidence whether the efficiency of AMPK responsiveness declines during the aging process. Next, we will review the mechanisms involved in curtailing the activation of AMPK. Finally, we will elucidate the potential age-related changes in the inhibitory regulation of AMPK signaling that might be a part of the aging process.     

Rho GTPases与肿瘤侵袭转移相关性的研究进展

Rho GTPases属小分子量GTPases,作为信号传导通路中重要的“分子开关”,调控细胞形态、骨架重建、迁移及细胞周期与凋亡等诸多过程.近来的研究表明,Rho GTPases家族成员在多种恶性肿瘤中异常表达,并通过调控上皮细胞极性丧失、细胞-细胞间的连接及黏附、细胞骨架重组和迁移运动、细胞外基质的重塑、细胞进入血管淋巴管的能力等方面参与肿瘤细胞的侵袭转移.深入研究Rho GTPases在肿瘤侵袭转移中的作用意义重大,Rho GT-Pases将有望成为判断肿瘤侵袭转移性发展的新指标,并为肿瘤治疗提供新靶点、新方向.     

Klotho promotes AMPK activity and maintains renal vascular integrity by regulating the YAP signaling pathway

The development and formation of mammalian blood vessels are closely related to the regulation of signal transduction pathways. Klotho/AMPK and YAP/TAZ signaling pathways are closely related to angiogenesis, but the internal relationship between them is not clear. In this study, we found that Klotho heterozygous deletion mice (Klotho^+/- mice) had obvious thickening of the renal vascular wall, obvious enlargement of vascular volume, and significant proliferation and pricking of vascular endothelial cells. Western blot showed that the expression levels of total YAP protein, p-YAP protein (Ser127 and Ser397), p-MOB1, MST1, LATS1, and SAV1 in renal vascular endothelial cells were significantly lower in Klotho^+/- mice than in wild-type mice. Knockdown of endogenous Klotho in HUVECs accelerated their ability to divide and form vascular branches in the extracellular matrix. Meanwhile, the results of CO-IP western blot showed that the expression of LATS1 and p-LATS1 interacting with AMPK protein decreased significantly, and the ubiquitination level of YAP protein also decreased significantly in vascular endothelial cells of kidney tissue of Klotho^+/- mice. Subsequently, continuous overexpression of exogenous Klotho protein in Klotho heterozygous deficient mice effectively reversed the abnormal renal vascular structure by weakening the expression of the YAP signal transduction pathway. Therefore, we confirmed that Klotho and AMPKα proteins were highly expressed in vascular endothelial cells of adult mouse tissues and organs; this resulted in a phosphorylation modification of YAP protein, closed the activity of the YAP/TAZ signal transduction pathway, and inhibited the growth and proliferation of vascular endothelial cells. When Klotho was absent, the phosphorylation modification of YAP protein by AMPKα was inhibited, resulting in the activation of the YAP/TAZ signal transduction pathway and finally inducing the excessive proliferation of vascular endothelial cells.