PAI与细胞凋亡

纤溶酶原激活物(PA)系统是体内重要的蛋白溶解复合物系统,主要参与降解细胞外基质。纤溶酶原激活物抑制剂(PAI),主要有PAI-1、PAI-2,是纤溶酶原激活物t-PA和u-PA的有效抑制物。最近研究证明,PAI与细胞凋亡存在较密切的关系:PAI-1和PAI-2可抑制细胞凋亡的发生;细胞内PAI-2的裂解产物可作为细胞凋亡的标志等。     

三七皂苷Rg1对tPA和PAI-1活性的调节作用

探讨三七皂苷Rg1对组织型纤溶酶原激活物(tPA)和纤溶酶原激活物抑制物(PAI-1)活性的调节作用。运用发色底物方法测定三七皂苷Rg1在体外和静脉注射对家兔血浆纤溶酶原激活物(tPA)和血浆或血小板释放的纤溶酶原激活物抑制物(PAI-1)水平的影响。结果表明,三七皂苷Rg1在体外呈浓度依赖性明显抑制血浆PAI-1活性,同时提高血浆tPA活性;30和60 mg/kg的三七皂苷Rg1静脉注射显著抑制血浆PAI-1活性,提高血浆tPA活性,同时降低凝血酶激活的血小板所释放的PAI-1水平。本实验提示三七皂苷Rg1能抑制PAI-1活性,同时升高tPA活性可能是其抗血栓作用的分子机制之一。     

uPA、PAI-1 的表达和MVD 计数与浸润性乳腺癌侵袭性的关系

目的:探讨尿激酶型纤溶酶原激活剂(uPA)、纤溶酶原激活物抑制剂(PAI-1)的表达和血管形成与浸润性乳腺癌侵袭性的关系。方法:应用免疫组化SP法检测80例浸润性乳腺癌、20例良性乳腺肿瘤组织中uPA、PAI-1的表达情况并进行微血管计数。结果:uPA和PAI-1在浸润性乳腺癌组的阳性表达显著高于良性肿瘤组,且其高表达率与乳腺癌的临床病理参数密切相关(P<0.05);微血管计数在乳腺癌组和良性肿瘤组分别为30.87±7.64、20.28±8.72,两组比较有显著性差异(P<0.01)。uPA与PAI-1在浸润性乳腺癌中的表达呈正相关(P<0.05)。结论:uPA、PAI-1的高表达与浸润性乳腺癌的浸润、转移相关,uPA、PAI-1的高表达和MVD计数可作为评价浸润性乳腺癌侵袭性、评估预后和确定治疗方案的生物学指标。     

螺旋藻激酶对肾上腺素损伤内皮细胞分泌t-PA和PAI-1的影响

研究不同浓度螺旋藻激酶(spirulina kinase,SPK)对肾上腺素(Adr)损伤血管内皮细胞分泌组织型纤溶酶原激活物(t-PA)和纤溶酶原激活物抑制剂(PAI-1)的影响。采用不同浓度SPK处理人脐静脉内皮细胞(HUVEC),MTT法检测不同浓度SPK对HUVEC活力影响;建立Adr损伤模型,酶联免疫吸附法检测细胞培养液中t-PA和PAI-1含量的变化。结果显示SPK浓度在10μg/mL~2 mg/mL范围内,细胞活力明显升高且不影响细胞分泌t-PA和PAI-1的量;SPK作用于Adr损伤模型,各剂量组均可降低Adr损伤下HUVEC分泌PAI-1的量,提高t-PA/PAI-1比值。本研究揭示了SPK可通过降低PAI-1、提高t-PA/PAI-1比值来实现保护Adr损伤的血管内皮细胞。     

uPA、PAI-1的表达和MVD计数与浸润性乳腺癌侵袭性的关系

目的：探讨尿激酶型纤溶酶原激活剂（uPA）、纤溶酶原激活物抑制剂（PAI-1）的表达和血管形成与浸润性乳腺癌侵袭性的关系。方法：应用免疫组化SP法检测80例浸润性乳腺癌、20例良性乳腺肿瘤组织中uPA、PAI-1的表达情况并进行微血管计数。结果：uPA和PAI-1在浸润性乳腺癌组的阳性表达显著高于良性肿瘤组,且其高表达率与乳腺癌的临床病理参数密切相关（P〈0.05）;微血管计数在乳腺癌组和良性肿瘤组分别为30.87±7.64、20.28±8.72,两组比较有显著性差异（P〈0.01）。uPA与PAI-1在浸润性乳腺癌中的表达呈正相关（P〈0.05）。结论：uPA、PAI-1的高表达与浸润性乳腺癌的浸润、转移相关,uPA、PAI-1的高表达和MVD计数可作为评价浸润性乳腺癌侵袭性、评估预后和确定治疗方案的生物学指标。     

急性脑梗死患者介入治疗的疗效及对患者纤溶系统的影响

目的:研究急性脑梗死患者脑血管球囊成形支架置入术治疗的临床疗效及其对患者纤溶系统的影响。方法:选择我院收治的急性脑梗死患者68例,随机分为观察1组和观察2组,各34例,观察1组给予尿激酶100万U静脉溶栓治疗;观察2组给予脑血管球囊成形支架置入术治疗,术后口服氯吡格雷和阿司匹林。观察两组患者治疗前、治疗后1d、7d组织型纤溶酶原激活物(t PA)、血浆血管性假血友病因子(v WF)、纤溶酶原激活物特异性抑制物(PAI-1)水平,并选择同期体检健康者30例作为对照组。结果:治疗后观察2组血流再通明显高于观察1组(P0.05);治疗前所有患者v WF、PAI-1、t PA明显高于对照组,t PA/PAI-1明显低于对照组(P0.05),但观察1组和观察2组比较无统计学差异(P0.05);治疗后1d观察1组、观察2组t PA、t PA/PAI-1明显升高,PAI-1明显降低(P0.05),治疗后7d,观察1组t PA、t PA/PAI-1明显降低,观察2组v WF明显升高(P0.05)。结论:脑血管球囊成形支架置入术治疗急性脑梗死可使梗死的血管再次通畅,术后采用抗凝及抗血小板治疗,效果显著,且对体内纤溶系统无明显影响,相比静脉溶栓治疗临床效果更加显著。     

封面说明

正食管癌是常见的恶性肿瘤之一,死亡率位居我国恶性肿瘤死因的第4位。肿瘤转移是导致食管癌患者死亡的重要原因,深入研究食管癌侵袭和转移的分子机制,将有助于改善食管癌的治疗,降低患者的死亡率。由SERPINE1基因编码的纤溶酶原激活物抑制因子1(plasminogenactivator inhibitor-1,PAI-1)被报道在多种类型     

I型纤溶酶原激活物抑制物在紫癜肾炎肾组织中的表达

为研究I型纤溶酶原激活物抑制物(PAI-1)在紫癜肾炎病理机制中的作用.采用免疫组织化学和原位杂交方法检测了23例紫癜肾炎患者肾组织中的PAI-1.结果证实:在正常肾组织内和紫癜肾炎肾组织内均可检测到PAI-1表达,PAI-1mRNA原位杂交阳性信号主要分布于血管平滑肌细胞和肾小管上皮细胞内,紫癜肾炎肾小球内有紫兰色阳性信号,且强度与肾小球内细胞的增生程度有关.     

GW501516通过TGFβ-Smad3信号途径促进人脐静脉内皮细胞PAI-1的表达

为探讨过氧化物酶体增殖物激活型受体δ(peroxisome proliferator-activated receptor-δ,PPARδ)激动剂GW501516对人脐静脉内皮细胞纤溶酶原激活物抑制剂1(PAI-1)表达的影响及机制,采用siRNA、TGFβ-Smad3信号通路阻滞剂等处理细胞,经实时定量PCR、Western blot方法分别检测细胞中PAI-1及磷酸化Smad3蛋白的表达.结果显示,与对照组比较,GW501516可诱导人脐静脉内皮细胞(HUVEC)中PAI-1表达,且此效应呈浓度和时间依赖性(P0.05);siRNA沉默PPARδ的表达后,可阻抑GW501516对HUVEC细胞PAI-1表达的促进作用;TGFβ-Smad3信号通路抑制剂SB-431542与SIS3均可降低HUVEC细胞pSmad3蛋白的表达,而细胞PAI-1表达也随之降低.结果提示,GW501516可促进HUVEC细胞PAI-1的表达,其机制可能与TGFβ-Smad3信号通路有关.     

Ⅱ型糖尿病视网膜病变与纤溶系统的关系探讨

目的:探讨2型糖尿痛视网膜病变与纤溶系统的关系。方法:随机选取2型糖尿病视网膜痛变患者30例,无并发症患者30例,健康人30例,测定血浆纤溶酶原、纤溶酶原激活抑制物,纤溶酶原(PLG)、纤溶酶原激活抑制物(PAI-1)均采用发色底物法检测。结果:与对照组相比2型糖尿病患者血浆PLG、PAI-1水平升高(P＜0．05),糖尿病视网膜病变组升高更明显(P＜0．01)。结论:糖尿病患者血液存在低纤状态,当发生视网膜并发症者更为明显,检测2型糖尿病患者血浆PLG、PAI-1水平对糖尿痛视网膜病变的预防及治疗具有一定的临床意义。     

Protein kinase C zeta regulates interleukin-8-mediated stromal-derived factor-1 expression and migration of human mesenchymal stromal cells

Mesenchymal stromal cells (MSCs) are bone marrow-derived cells with multipotent differentiation capability that are mobilized into the circulation in response to injury and localize to areas of tissue damage including solid tumors. They have the capacity to adopt a phenotype similar to carcinoma-associated fibroblasts (CAFs) and, like CAFs, promote tumor growth. The molecular communication between tumor cells and MSCs has not been well defined. However, MSCs have increased expression of the chemokine stromal-derived factor 1 (SDF-1) when exposed to conditioned medium from tumor cells. Additionally, SDF-1 has been shown to be important in the promotion of tumor growth by CAFs. These data suggest that the SDF-1 signaling axis is a key feature of the tumor microenvironment. In this report, we demonstrate that interleukin 8 (IL-8) induces an increase in SDF-1 expression by MSCs. The increase in SDF-1 expression in response to IL-8 is mediated by the activation of the protein kinase C (PKC) zeta isoform. In a functional assay, activation of PKC is required for in vitro MSC migration in response to tumor conditioned medium. These results indicate that IL-8-mediated SDF-1 production by MSCs requires PKC zeta activation. This signaling pathway provides insight into possible molecular targets for cancer therapy aimed at disrupting the interaction between components of the tumor microenvironment.     

The plasminogen activator inhibitor PAI-1 controls in vivo tumor vascularization by interaction with proteases, not vitronectin. Implications for antiangiogenic strategies

The plasminogen (Plg)/plasminogen activator (PA) system plays a key role in cancer progression, presumably via mediating extracellular matrix degradation and tumor cell migration. Consequently, urokinase-type PA (uPA)/plasmin antagonists are currently being developed for suppression of tumor growth and angiogenesis. Paradoxically, however, high levels of PA inhibitor 1 (PAI-1) are predictive of a poor prognosis for survival of patients with cancer. We demonstrated previously that PAI-1 promoted tumor angiogenesis, but by an unresolved mechanism. We anticipated that PAI-1 facilitated endothelial cell migration via its known interaction with vitronectin (VN) and integrins. However, using adenoviral gene transfer of PAI-1 mutants, we observed that PAI-1 promoted tumor angiogenesis, not by interacting with VN, but rather by inhibiting proteolytic activity, suggesting that excessive plasmin proteolysis prevents assembly of tumor vessels. Single deficiency of uPA, tissue-type PA (tPA), uPA receptor, or VN, as well as combined deficiencies of uPA and tPA did not impair tumor angiogenesis, whereas lack of Plg reduced it. Overall, these data indicate that plasmin proteolysis, even though essential, must be tightly controlled during tumor angiogenesis, probably to allow vessel stabilization and maturation. These data provide insights into the clinical paradox whereby PAI-1 promotes tumor progression and warrant against the uncontrolled use of uPA/plasmin antagonists as tumor angiogenesis inhibitors.     

Breast cancer and metabolic syndrome linked through the plasminogen activator inhibitor-1 cycle

Plasminogen activator inhibitor-1 (PAI-1) is a physiological inhibitor of urokinase (uPA), a serine protease known to promote cell migration and invasion. Intuitively, increased levels of PAI-1 should be beneficial in downregulating uPA activity, particularly in cancer. By contrast, in vivo, increased levels of PAI-1 are associated with a poor prognosis in breast cancer. This phenomenon is termed the "PAI-1 paradox". Many factors are responsible for the upregulation of PAI-1 in the tumor microenvironment. We hypothesize that there is a breast cancer predisposition to a more aggressive stage when PAI-1 is upregulated as a consequence of Metabolic Syndrome (MetS). MetS exerts a detrimental effect on the breast tumor microenvironment that supports cancer invasion. People with MetS have an increased risk of coronary heart disease, stroke, peripheral vascular disease and hyperinsulinemia. Recently, MetS has also been identified as a risk factor for breast cancer. We hypothesize the existence of the "PAI-1 cycle". Sustained by MetS, adipocytokines alter PAI-1 expression to promote angiogenesis, tumor-cell migration and procoagulant microparticle formation from endothelial cells, which generates thrombin and further propagates PAI-1 synthesis. All of these factors culminate in a chemotherapy-resistant breast tumor microenvironment. The PAI-1 cycle may partly explain the PAI-1 paradox. In this hypothesis paper, we will discuss further how MetS upregulates PAI-1 and how an increased level of PAI-1 can be linked to a poor prognosis.     

TGF-β对肿瘤微环境中免疫监视及细胞外基质的调控作用

转化生长因子β(transforming growth factorβ,TGF-β)是一种多功能的细胞因子,能够调控细胞增殖、分化、黏附、迁移及凋亡等行为,在胚胎发育过程和成体组织稳态维持中发挥重要的作用。而在许多疾病状态下,特别是在癌症中,TGF-β不仅能够影响肿瘤细胞的增殖与转移,其对于肿瘤微环境的调控与塑造也受到越来越多的关注。肿瘤微环境是指肿瘤在发生和发展过程中所处的内环境,由肿瘤细胞本身、相邻正常组织中的间质细胞,以及这些细胞所释放的众多细胞因子等共同组成。肿瘤微环境是肿瘤发展的重要机制,也是肿瘤临床治疗领域亟待探索的关键问题。TGF-β是调节肿瘤微环境组成和功能的主要参与者之一。在本综述中,将着重讨论TGF-β对于肿瘤微环境中的免疫监视机制及肿瘤细胞外基质的主要影响。即TGF-β对于构成先天性和获得性抗肿瘤免疫应答的各种类群的免疫细胞具有广泛的调控作用,从而削弱宿主的肿瘤免疫监视功能。同时,TGF-β通过促进肿瘤相关成纤维细胞的产生,以及肿瘤细胞外基质的纤维化,有助于肿瘤的恶变和转移。此外,还介绍了通过阻断肿瘤微环境中TGF-β信号通路进行肿瘤治疗的主要策略及独特优势。而未来进一步解析TGF-β信号在肿瘤微环境中的复杂调控作用,并建立有效的靶向干预方法对于开发高效的抗肿瘤药物具有重要的意义。     

NK cells: An attractive candidate for cancer therapy

Natural killer (NK) cells have significant capability in tumor immune-surveillance. The ability of lyse transformed cells immediately in an antigen-independent manner make them an attractive candidate for cancer cell therapy. Despite employment of NK cells in cancer immunotherapy, clinical trials are faced with serious limitations such as trouble with the penetration of NK cells in tumor sites, limited in vivo persistence, and tumor microenvironment interference. Taken together, the NK-cell cancer therapy is still infant scenario that has a long way to be translated in clinic. Current article first reviews characteristic features of NK lymphocytes. Then, it discusses about important disruptive barriers and motivator in the developmental stages of NK cells like as tumor microenvironment. Finally, some revolutionary approaches are highlighted utilizing of NK cells in cancer therapy.     

FGFR2 upregulates PAI-1 via JAK2/STAT3 signaling to induce M2 polarization of macrophages in colorectal cancer

Fibroblast growth factor receptor 2 (FGFR2) is frequently activated by overexpression or mutation, and an abnormal fibroblast growth factor (FGF)/FGFR signaling pathway is associated with the occurrence, development, and poor prognosis of colorectal cancer (CRC). Our preliminary analysis found that plasminogen activator inhibitor-1 (PAI-1) expression may be related to FGF/FGFR signaling, however, their role in the tumor immune microenvironment remains unclear. In this study, we observed markedly higher PAI-1 expression in CRC patients with poor survival rates. PAI-1 is regulated by FGF/FGFR2 in colon cancer cells and is involved in M2 macrophage polarization. Mechanistically, inhibiting the JAK2/STAT3 signaling pathway could cause PAI-1 downregulation. Furthermore, the activation of phosphorylated STAT3 upregulated PAI-1. In vivo, FGFR2 overexpression in tumor-bearing mouse models suggested that a PAI-1 inhibitor could rescue FGFR2/PAI-1 axis-induced M2 macrophage polarization, which leads to effective immune activity and tumor suppression. Moreover, the combination of a PAI-1 inhibitor and anti-PD-1 therapy exhibited superior antitumor activity in mice. These findings offer novel insights into the molecular mechanisms underlying tumor deterioration and provide potential therapeutic targets for CRC treatment.     

Matrix remodeling stimulates stromal autophagy, “fueling” cancer cell mitochondrial metabolism and metastasis

We have previously demonstrated that loss of stromal caveolin-1 (Cav-1) in cancer-associated fibroblasts is a strong and independent predictor of poor clinical outcome in human breast cancer patients. However, the signaling mechanism(s) by which Cav-1 downregulation leads to this tumor-promoting microenvironment are not well understood. To address this issue, we performed an unbiased comparative proteomic analysis of wild-type (WT) and Cav-1^-/- null mammary stromal fibroblasts (MSFs). Our results show that plasminogen activator inhibitor type 1 and type 2 (PAI-1 and PAI-2) expression is significantly increased in Cav-1^-/- MSFs. To establish a direct cause-effect relationship, we next generated immortalized human fibroblast lines stably overexpressing either PAI-1 or PAI-2. Importantly, PAI-1/2(+) fibroblasts promote the growth of MDA-MB-231 tumors (a human breast cancer cell line) in a murine xenograft model, without any increases in angiogenesis. Similarly, PAI-1/2(+) fibroblasts stimulate experimental metastasis of MDA-MB-231 cells using an in vivo lung colonization assay. Further mechanistic studies revealed that fibroblasts overexpressing PAI-1 or PAI-2 display increased autophagy (“self-eating”) and are sufficient to induce mitochondrial biogenesis/activity in adjacent cancer cells, in co-culture experiments. In xenografts, PAI-1/2(+) fibroblasts significantly reduce the apoptosis of MDA-MB-231 tumor cells. The current study provides further support for the “Autophagic Tumor Stroma Model of Cancer” and identifies a novel “extracellular matrix”-based signaling mechanism, by which a loss of stromal Cav-1 generates a metastatic phenotype. Thus, the secretion and remodeling of extracellular matrix components (such as PAI-1/2) can directly regulate both (1) autophagy in stromal fibroblasts and (2) epithelial tumor cell mitochondrial metabolism.     

靶向肿瘤酸性微环境的抗肿瘤新策略

越来越多的体内体外实验及临床检测都证明了肿瘤酸性微环境对肿瘤的发生、发展和迁移起着重要作用。在肿瘤酸性微环境的重要调节因子中,V型ATP酶（V-ATPases）的作用至关重要。这些蛋白能将离子泵出膜外,在正常细胞和肿瘤细胞中都有着多种功能。本文回顾和总结了该领域的最新研究成果：在异种移植人肿瘤细胞的动物模型中,体内实验显示,采用小分子干扰RNA（siRNA）可抑制V．ATPaseS的功能,加入药物性质子泵抑制剂可显著地抑制人肿瘤细胞的生长。这些结果提示V-ATPases可作为癌症治疗中一个重要的新选择靶标。     

Matrix-bound PAI-1 supports cell blebbing via RhoA/ROCK1 signaling

The microenvironment of a tumor can influence both the morphology and the behavior of cancer cells which, in turn, can rapidly adapt to environmental changes. Increasing evidence points to the involvement of amoeboid cell migration and thus of cell blebbing in the metastatic process; however, the cues that promote amoeboid cell behavior in physiological and pathological conditions have not yet been clearly identified. Plasminogen Activator Inhibitor type-1 (PAI-1) is found in high amount in the microenvironment of aggressive tumors and is considered as an independent marker of bad prognosis. Here we show by immunoblotting, activity assay and immunofluorescence that, in SW620 human colorectal cancer cells, matrix-associated PAI-1 plays a role in the cell behavior needed for amoeboid migration by maintaining cell blebbing, localizing PDK1 and ROCK1 at the cell membrane and maintaining the RhoA/ROCK1/MLC-P pathway activation. The results obtained by modeling PAI-1 deposition around tumors indicate that matrix-bound PAI-1 is heterogeneously distributed at the tumor periphery and that, at certain spots, the elevated concentrations of matrix-bound PAI-1 needed for cancer cells to undergo the mesenchymal-amoeboid transition can be observed. Matrix-bound PAI-1, as a matricellular protein, could thus represent one of the physiopathological requirements to support metastatic formation.     

VEGF/VEGFR-Targeted Therapy and Immunotherapy in Non-small Cell Lung Cancer: Targeting the Tumor Microenvironment

Non-small cell lung cancer (NSCLC) is the leading cause of death by cancer worldwide. Despite developments in therapeutic approaches for the past few decades, the 5-year survival rate of patients with NSCLC remains low. NSCLC tumor is a complex, heterogeneous microenvironment, comprising blood vessels, cancer cells, immune cells, and stroma cells. Vascular endothelial growth factors (VEGFs) are a major mediator to induce tumor microvasculature and are associated with the progression, recurrence, and metastasis of NSCLC. Current treatment medicines targeting VEGF/VEGF receptor (VEGFR) pathway, including neutralizing antibodies to VEGF or VEGFR and receptor tyrosine kinase inhibitors, have shown good treatment efficacy in patients with NSCLC. VEGF is not only an important angiogenic factor but also an immunomodulator of tumor microenvironment (TME). VEGFs can suppress antigen presentation, stimulate activity of regulatory T (Treg) cells, and tumor-associated macrophages, which in turn promote an immune suppressive microenvironment in NSCLC. The present review focuses on the angiogenic and non-angiogenic functions of VEGF in NSCLC, especially the interaction between VEGF and the cellular components of the TME. Additionally, we discuss recent preclinical and clinical studies to explore VEGF/VEGFR-targeted compounds and immunotherapy as novel approaches targeting the TME for the treatment of NSCLC.