Talin及Integrin/FAK信号通路与肝癌

肿瘤细胞黏附能力的改变是肿瘤细胞侵袭和转移的起始;整合素(integrin)是细胞表面重要的黏附分子受体,介导许多信号通路的发生,包括Integrin/黏着斑激酶(focal adhesion kinase,FAK)信号通路,直接或间接地影响肿瘤复发和转移,其中Integrin/FAK信号转导通路,在Integrin介导的肝癌黏附转移信号转导通路中起着至关重要的作用.踝蛋白(Talin)是第一个被证实的Integrin活化蛋白,是黏着斑(focal adhesion plaque,FAP)结构的重要组成部分.本文就Talin结构、功能、与Integrin/FAK信号通路的相互作用及其与肝癌及其他肿瘤的关系作一综述.     

Talin及Integrin/FAK信号通路与肝癌

肿瘤细胞黏附能力的改变是肿瘤细胞侵袭和转移的起始;整合素(integrin)是细胞表面重要的黏附分子受体,介导许多信号通路的发生,包括Integrin/黏着斑激酶(focal adhesion kinase,FAK)信号通路,直接或间接地影响肿瘤复发和转移,其中Integrin/FAK信号转导通路,在Integrin介导的肝癌黏附转移信号转导通路中起着至关重要的作用.踝蛋白(Talin)是第一个被证实的Integrin活化蛋白,是黏着斑(focal adhesion plaque,FAP)结构的重要组成部分.本文就Talin结构、功能、与Integrin/FAK信号通路的相互作用及其与肝癌及其他肿瘤的关系作一综述.     

Talin-1与肝癌的研究进展

正原发性肝癌是消化系统常见的恶性肿瘤,最新研究报道其年死亡率仅次于胃癌和肺癌而居肿瘤死亡率的第三位[1]。复发和转移是肝癌的突出特点,同时也是治疗的难点。Talin是一种位于细胞外基质上能与多种粘附分子(如整合素、肌动蛋白及粘着激酶等)结合的大分子细胞骨架蛋白[2]。Talin也是黏着斑(focal adhesion plaque,FAP)的重要组分,其可通过活化整合素(Integrin)而激活integrin/黏着斑     

黏着斑激酶在机械通气相关性肺损伤中的作用

背景 机械通气相关性肺损伤(ventilator-induced lung injury,VILI)是指应用呼吸机过程中由于机械通气的各种因素与肺部原发病共同作用导致的肺组织损伤.肺损伤过程中肺微血管的完整性破坏及通透性改变是引起VILI的根本原因.紧密连接(tight junction,TJ)及黏附连接(adherent junction,AJ)是细胞连接的主要方式,对维持肺的正常功能起着重要作用.黏着斑激酶(focal adhesion kinase,FAK)主要作用于细胞膜黏附连接的黏着斑部位,能维持黏着斑蛋白在细胞膜的表达,对AJ及血管通透性具有重要作用. 目的 通过对FAK在VILI中的作用的研究指导临床实践. 内容 探讨机械通气对FAK的影响及FAK对AJ、TJ的影响和作用. 趋向 进一步明确FAK在VILI发生过程中的作用,为临床预防及治疗VILI提供新思路及理论依据.     

黏着斑激酶与肝癌侵袭、转移的研究进展

黏着斑激酶(FAK)是一种位于胞质内的非受体酪氨酸激酶,在细胞、胚胎、器官发育中发挥重要的生物学功能,同时与肿瘤的发生、发展关系密切。本文就FAK与肝癌的侵袭、转移的研究进展作一综述。     

黏着斑激酶介导信号通路在瓣膜性心房颤动心房纤维化中的研究

目的探索黏着斑激酶(FAK)在瓣膜性心房颤动(房颤)患者纤维化心房中的变化,并对其介导的下游信号通路进行探究。方法共有45例二尖瓣疾病患者纳入本次研究,根据有无房颤分为瓣膜房颤组(VAF,≥6个月,25例)和窦性心律组(SR,20例)。术中获取心耳组织,分别进行组织学病理检测和蛋白免疫印迹。观察心房纤维化程度、 FAK及其下游通路在纤维化心肌中的变化。结果本研究揭示了瓣膜性房颤心房纤维化程度较高,细胞排列紊乱。通过探究FAK及下游通路的变化,发现房颤组成纤维细胞分化标志蛋白α平滑肌肌动蛋白(α-SMA)表达明显升高,FAK及下游AKT/S6K通路蛋白表达均发生上调,而另一条信号通路ERK1/2信号通路未见明显变化。结论瓣膜性房颤心房纤维化是心房结构重塑的一个重要标志,胶原纤维的过度产生使心房肌细胞的连续性受到破坏,导致传导异常,为房颤发生发展提供了基质环境。FAK及下游AKT/S6K信号通路在纤维化心肌中表达增加,可能参与心房纤维化进程之中,为其机制研究提供依据。     

Leupaxin参与调控前列腺癌转移的分子机制

Leupaxin(LPXN)是近年发现的一种桩蛋白家族新成员,主要定位于黏着斑,参与多种信号通路的转导,调控肿瘤细胞的增殖、黏附与迁移。在前列腺癌细胞中,LPXN不仅参与整合素信号通路的转导,调控前列腺癌细胞的增殖、黏附与迁移,而且作为一个新的雄激素受体(AR)共激活因子,调节胞核内AR效应基因的转录、AR信号的转导,以及前列腺癌细胞的分化与侵袭。本文就LPXN的分子结构、LPXN在前列腺癌转移中的具体作用及相关分子机制进行综述。     

黏着斑激酶表达下调对肝癌细胞黏附迁移侵袭行为的影响

目的研究下调黏着斑激酶（FAK）表达对人肝癌细胞HCC-LM3黏附迁移侵袭行为的影响及可能涉及的机制。 方法根据处理方法不同,将人肝癌细胞HCC-LM3分为未处理组（肿瘤细胞未经处理）、对照组（肿瘤细胞转染空载体,FAK表达未改变）和FAK-shRNA组（肿瘤细胞稳定低表达FAK）。分别采用细胞黏附实验、划痕实验、Transwell实验检测3组肝癌细胞的黏附、迁移、侵袭能力,Western blotting检测细胞黏附侵袭相关蛋白paxillin、p130Cas以及基质金属蛋白酶MMP-2与MMP-9蛋白的表达及活化情况。 结果FAK表达下调后,细胞黏附能力显著受到抑制,细胞迁移能力和侵袭能力均明显下降;细胞黏附分子p130Cas、paxillin的蛋白总量表达无明显改变,而磷酸化水平明显降低,其活化形式p-paxillin和p-p130Cas表达则明显受到抑制;MMP-2、MMP-9蛋白表达水平则在下调FAK表达后明显降低（P<0.01）。 结论在人肝癌细胞HCC-LM3中,下调FAK表达可以影响肝癌细胞黏附迁移侵袭能力,其机制可能是通过调节相关细胞黏附分子的表达或活化来实现。     

FAK和MMP-9蛋白在结直肠癌组织中的表达及相关性研究

目的 探讨斑激酶(focal adhesion kinase , FAK)和基质金属蛋白酶-9(matrix metalloproteinase,MMP-9)在结直肠癌中的表达.方法 采用免疫组化法检测了67例结直肠癌和癌旁组织以及51例正常结直肠黏膜组织中FAK和MMP-9的表达,并比较了不同临床病理参数下FAK和MMP-9的表达情况.结果 结直肠癌组织FAK阳性表达(77.6%,52/67)高于癌旁组织(50.8%,34/67)和正常结直肠黏膜组织(37.3%,19/51),结直肠癌组织中MMP-9染色阳性率(73.1%,49/67)高于癌旁组织(49.3%,33/67)和正常结直肠黏膜组织(31.4%,16/51),不同肿瘤分化、局部分期以及有无淋巴结转移者FAK和MMP-9表达水平存在差异(P<0. 05).结论 FAK和MMP-9在结直肠癌组织高表达,且FAK和MMP-9表达呈正相关,可能成为判断结直肠癌预后的指标之一.     

反义寡核苷酸对人增生性瘢痕成纤维细胞FAK和胶原合成的作用

目的 研究黏着斑激酶(focal adhesion kinase,FAK)在人增生性瘢痕发病机制中的作用.方法 体外分离、培养人增生性瘢痕成纤维细胞(hyperthrophic scar fibroblasts,HSFB).在脂质体介导下将FAK反义寡核苷酸转染至HSFB中设为FAK反义寡核苷酸治疗组(AT组),仅加入脂质体为脂质体对照组(LPC组),不加脂质体和反义寡核苷酸为空白对照组(LC组).通过荧光定量PCR方法 检测HSFB细胞中FAK mRNA指数,采用3H-脯氨酸掺入法测定HSFB细胞的胶原合成量.结果 转染48 h后,AT组FAKmRNA值为0.043±0.030,明显低于LC组(0.124±0.070)及LPC组(0.127±0.0195,P＜0.05).AT组的3H-脯氨酸掺入率为257.0±15.14,低于LC组(962.2±300.5)及LPC组(930.8±28.97,P＜0.01).结论 FAK反义寡核苷酸能抑制体外培养的HSFB中FAK基因的表达和胶原合成,FAK在人增生性瘢痕的发病中发挥了一定作用.     

Expression of focal adhesion kinase in normal and pathologic human prostate tissues

BACKGROUND: Focal adhesion kinase (FAK) regulates multiple cellular processes including growth, differentiation, adhesion, motility, and apoptosis. In tumor cells, including prostate adenocarcinoma, FAK overexpression has been linked to cancer progression. METHODS: By using immunohistochemistry, FAK expression was investigated in human prostate specimens. RESULTS: FAK was expressed predominantly in the basal layer of normal prostate epithelium but not in secretory epithelium. FAK was expressed at similar levels in all stages of prostate tumorigenesis, including preinvasive carcinoma and metastatic disease. Elevated FAK expression was observed at the earliest stages of transformation and expression continued during cancer progression. CONCLUSION: Given the established role for FAK in the regulation of integrin signaling, we suggest that the sustained elevated levels of FAK expression during prostate tumor cell progression is consistent with a role for FAK in the development and maintenance of prostate carcinoma.     

Mechanisms by Which the Extracellular Matrix and Integrin Signaling Act to Regulate the Switch Between Tumor Suppression and Tumor Promotion

Cell adhesion to the extracellular matrix (ECM) is necessary for development of the mammary gland, and to maintain the normal architecture and function of the gland. Cells adhere to the ECM via the integrin family of trans-membrane receptors, which signal to control mammary-specific gene expression and regulate cell proliferation and survival. During tumor formation, the ECM is extensively remodeled and signaling through integrins is altered such that cells become proliferative and invasive. A key regulator of whether integrin-mediated adhesion will promote tumor suppression or tumor formation is the stiffness of the stromal ECM. The normal mammary gland is typically surrounded by a loose collagenous stroma. An increase in the deposition of collagen and other stromal components is associated with mammographic density, which is one of the greatest risk factors for developing breast carcinoma. Several groups have demonstrated that increased stromal ECM density results in a matrix that is stiffer. Cells sense the stiffness of their surrounding ECM by Rho-mediated contraction of the actin-myosin cytoskeleton. If the surrounding ECM is stiffer than the cell’s ability to contract it, then the tensile forces that result are able to drive the clustering of integrins and assemble adhesion signaling complexes. The result is subsequent activation of signaling pathways including FAK, ERK, and PI3K that drive cell proliferation and survival. In contrast, focal complexes are not formed in a compliant matrix, and activation of FAK and pERK is diminished, resulting in control of proliferation. Signaling from FAK moreover regulates p53 and miR-200 members, which control apoptosis and epithelial phenotype, such that a compliant matrix is predicted to promote normal mammary gland architecture and suppress tumor formation.     

CXCR4/CXCL12信号途径在食管鳞癌浸润转移中的作用机制

目的研究趋化因子受体4(CXCR4)/趋化因子12(CXCL12)信号途径在食管鳞癌浸润转移中的作用机制,为探讨CXCR4成为食管癌治疗新的靶点提供理论依据。 方法取对数生长期的食管鳞癌EC9706细胞,添加趋化因子CXCL12,通过侵袭转移实验、黏附实验分别检测食管鳞癌EC9706细胞株的细胞侵袭、移动和黏附能力。采用RT-PCR和Western Blot技术检测表皮生长因子受体(EGFR)mRNA及蛋白的表达水平。 结果添加不同浓度趋化因子CXCL12(终浓度为5、10 μg/ml),食管鳞癌EC9706细胞株的细胞侵袭、移动和黏附能力均较空白对照组高,并且存在剂量依存关系,即CXCL12浓度越高,细胞的侵袭、移动、黏附能力越强,差异均有统计学意义(P<0.01)。添加不同浓度趋化因子CXCL12,食管鳞癌细胞的EGFR mRNA和蛋白表达水平均较对照组高,并且存在剂量依存关系,即CXCL12浓度越高,EGFR mRNA和蛋白表达水平越高,差异均有统计学意义(P<0.01)。 结论CXCR4/CXCL12信号途径与食管鳞癌细胞的侵袭、转移相关,并且存在剂量依存关系,有可能通过调控EGFR的表达参与食管鳞癌的浸润转移。     

整合素β1在甲状腺乳头状癌组织中的表达及临床意义

目的：明确甲状腺乳头状癌（PTC）组织中整合素β1的表达情况,明确整合素β1在PTC发生发展中的作用。方法：免疫组织化学方法检测64例PTC组织、10例正常甲状腺组织和15例甲状腺瘤组织中整合素β1的表达情况,分析整合素β1与肿瘤分期、年龄、性别和淋巴结转移等的相关性。结果：整合素β1在正常组织和良性腺瘤中不表达或微量表达,在PTC组织中表达较强,并随着肿瘤分期的升高而升高,在伴有淋巴结转移的肿瘤组织中,整合素β1的表达较无淋巴结转移者明显增高（P〈0.05）;与年龄和性别无相关性（P〉0.05）。结论：PTC组织中整合素β1的表达与其恶性程度、转移有关。     

Focal adhesions and associated proteins in medullary thyroid carcinoma cells

BACKGROUND: In medullary thyroid carcinoma (MTC), mutations in the RET protooncogene lead to oncogenic transformation. RET activation in other cell types has been shown to cause phosphorylation of the focal adhesion-associated proteins focal adhesion kinase (FAK), paxillin, and p130(CAS). We hypothesized that adhesion-dependent signaling might be deranged in MTC cells. METHODS: Indirect immunofluorescence was used to label beta(1) integrin, FAK, paxillin, and p130CAS. Rhodamine-labeled phalloidin was used to visualize actin microfilaments. Phosphorylated protein was detected by immunoprecipitation followed by Western blotting for phosphotyrosine. MTC cell invasiveness was quantified using a modified Boyden chamber assay. RESULTS: Clustering of beta(1) integrin, FAK, paxillin, and p130(CAS) into focal adhesions were not detected in MTC cells under any conditions, although clustering was seen as expected in control HeLa cells. Despite this failure, FAK, paxillin and p130(CAS) were all found to be phosphorylated. Actin microfilaments were generally not seen although in a few cells, small, poorly formed microfilaments could be detected. MTC cells invaded poorly as compared with highly invasive cell lines. However a clear difference was noted between invasiveness on growth factor depleted Matrigel and regular Matrigel. CONCLUSIONS: In MTC cells, focal adhesions are not seen in response to interaction with extracellular matrix. Consistent with this failure, actin microfilaments are absent or poorly formed and invasion is weak. Despite the absence of focal adhesions, focal adhesion proteins remain phosphorylated, even though in normal cells their signaling activity is dependent on focal adhesion formation. Deranged adhesion-dependent signaling may contribute to MTC pathogenesis.     

Integrin β1表达与肝癌组织硬化程度及病理特征相关研究

目的 检测整合素β1在肝癌组织中不同部位的表达,探讨整合素β1与肝癌发生、浸润、转移和复发的关系.方法 应用RT-PCR和激光扫描共聚焦显微镜免疫荧光染色方法分别检测71例肝癌病人的肝癌、癌旁和肝癌远处肝组织中整合素β1mRNA及蛋白的表达水平和分布情况,分析整合素β1基因的表达与肝癌临床、病理参数的关系.结果 (1)癌旁、肝癌远处肝组织中整合素β1mRNA及蛋白的表达与肝纤维化硬化程度呈正相关;(2)整合素β1mRNA及蛋白的表达与肝癌病理分级.包膜侵犯,远处转移,HBsAg感染呈正相关.结论 整合素β1可能参与肝纤维化-肝硬化-肝癌这一动态的病理过程改变,与肝癌的发生、侵袭和转移有关.