赖氨酰氧化酶样蛋白－2与肿瘤

赖氨酰氧化酶样蛋白－2（ lysyl oxidase－like 2 protein, LOXL2）在细胞外主要参与胶原蛋白与弹性蛋白之间的交联作用。 LOXL2的功能很广泛,除了维持细胞间的稳定性,还参与了肿瘤的形成及侵袭转移过程。肿瘤的发生发展是一个多因素、多机制的复杂过程,深入研究LOXL2在肿瘤之间的作用机制具有重要的临床意义。     

赖氨酰氧化酶样蛋白-2的研究进展

赖氨酰氧化酶家族发挥着多种重要的生物学功能,并参与肿瘤的发生、发展,赖氨酰氧化酶样蛋白-2(Lysyl Oxidase-Like 2 protein,LOXL2)就是该家族的成员之一。本文对LOXL2的基因结构,组织表达的特异性及其与肿瘤发生发展的关系作一综述,以期加深对肿瘤侵袭转移机制的认识,并为肿瘤侵袭转移的干预提供新靶标。     

肺癌中赖氨酰氧化酶样蛋白2的研究进展

赖氨酰氧化酶样蛋白2(lysyl oxidase-like protein-2,LOXL2)是一种铜依赖性胺氧化酶,其过表达可导致肿瘤细胞的增殖、侵袭和转移.大量研究表明LOXL2在肺癌中的高表达与上皮-间质转化、转移、肿瘤进展和预后不良有关.该文主要对LOXL2蛋白的结构、生物学作用、在肺癌中的表达与预后价值进行综述...     

子宫主韧带中弹性蛋白、赖氨酰氧化酶表达与盆底器官膨出的关系

目的：检测女性盆底器官膨出（POP）患者子宫主韧带中弹性蛋白（elastin）和赖氨酰氧化酶（LOX）表达,探讨两种基因与POP发生发展的关系。方法：选择因子宫脱垂而行全子宫切除术的患者60例,同期选择因妇科良性疾病、无压力性尿失禁（SUI）或POP行全子宫切除术患者60例作为对照。于手术中取子宫主韧带,采用逆转录-聚合酶链式反应（RT-PCR）法测定elastin、LOX mRNA的表达,免疫蛋白印迹法（Western blotting）检测两种蛋白表达。结果：无论绝经与否,POP组子宫主韧带中elastin、LOX mRNA及其蛋白表达明显低于对照组,POP组中绝经后患者elastin、LOX mRNA及其蛋白表达明显低于绝经前患者,差异显著（P<0.05）;子宫主韧带elastin mRNA及蛋白表达变化与LOX相应水平呈明显的直线正相关（r＝0.9959,r＝0.9708,P<0.05）。结论:POP患者子宫主韧带elastin表达减弱影响弹性纤维形成, LOX表达减弱可能通过影响胶原与弹性纤维的交联亦使盆腔支持结构稳定性降低,从而导致POP的发生;绝经后女性体内雌激素水平的降低可能通过影响LOX的表达,进而参与POP的发生。     

高碳酸血症通过赖氨酰氧化酶依赖的胶原蛋白交联影响大鼠缺氧性肺动脉高压

目的:通过研究缺氧和/或高碳酸血症时赖氨酰氧化酶(LOX)以及细胞外基质胶原蛋白的交联变化,探讨高碳酸血症对缺氧性肺动脉高压的影响机制。方法:SD大鼠随机均分为4组,分别为常氧对照组、缺氧组、高碳酸血症组以及缺氧+高碳酸血症组。比色法测定胶原蛋白含量,荧光光谱法分析LOX酶活性,免疫组织化学和Western blot法检测肺动脉LOX蛋白含量,实时荧光定量PCR检测肺动脉LOX的mRNA水平。结果:缺氧组大鼠平均肺动脉压(m PAP)、右心室/(左心室+室间隔)重量比值[RV/(LV+S)]及血管壁面积(WA)/血管总面积(TA)均明显高于常氧对照组;高碳酸血症组与常氧对照组的m PAP、RV/(LV+S)差异无统计学显著性;缺氧+高碳酸血症组大鼠的m PAP及RV/(LV+S)显著低于单纯缺氧组。缺氧组大鼠肺组织的胶原交联程度则明显高于常氧组及高碳酸血症组;高碳酸血症组大鼠肺组织的胶原交联程度与常氧组比较无显著差异;缺氧+高碳酸血症组大鼠肺组织的胶原交联程度显著低于缺氧组。缺氧组大鼠肺动脉LOX的mRNA、蛋白表达量及其酶活性均高于常氧组(P0.01);缺氧+高碳酸血症组大鼠肺动脉LOX mRNA、蛋白表达以及酶活性均明显低于缺氧组(P0.01)。结论:缺氧能诱导肺动脉LOX高表达,通过促进胶原合成及交联,参与肺动脉高压的形成。高碳酸血症通过抑制缺氧诱导的LOX表达和胶原交联,延缓缺氧性肺动脉高压的进展。     

下调赖氨酰氧化酶样蛋白1(LOXL1)表达抑制乳腺癌细胞的增殖与迁移

目的 探究赖氨酰氧化酶样蛋白1(LOXL1)基因对乳腺癌细胞的增殖及迁移能力的影响。方法 利用基因表达谱交互分析(GEPIA)与Kaplan-Meier分析确定乳腺癌组织LOXL1的表达以及与乳腺癌患者预后的关系。通过慢病毒稳定转染技术,稳定敲低MDA-MB-231细胞和MCF7细胞的LOXL1。采用集落形成实验、 CCK-8法、 5-乙炔基-2′脱氧尿嘧啶核苷(EdU)染色实验检测敲低LOXL1对乳腺癌细胞增殖能力的影响,划痕实验以及Transwell^TM实验检测敲低LOXL1对乳腺癌细胞迁移能力的影响。结果 与正常组织相比,LOXL1在乳腺癌组织高表达,且与不良预后相关;敲低MDA-MB-231、 MCF7乳腺癌细胞LOXL1后,细胞增殖和迁移能力明显降低。结论 敲低LOXL1降低乳腺癌细胞的增殖及迁移能力。     

N-乙酰基-丝氨酰-天门冬酰-赖氨酰-脯氨酸对大鼠矽肺的结缔组织生长因子和ERK1/2表达的调节作用

目的:探讨N-乙酰基-丝氨酰-天门冬酰-赖氨酰-脯氨酸(AcSDKP)对大鼠矽肺纤维化模型肺组织中胶原含量、结缔组织生长因子(CTGF)和细胞外信号调节激酶 1/2(ERK1/2)表达的影响.方法:选用非暴露式气管灌注法复制大鼠矽肺模型,并给予AcSDKP,采用羟脯氨酸测量法定量分析肺组织中总胶原蛋白的含量,免疫组织化学法、免疫印迹法检测肺组织内CTGF、phospho-ERK1/2及ERK1/2蛋白的表达.结果:AcSDKP治疗组胶原含量低于相对应的矽肺模型组.与相应的对照组相比,矽肺模型组大鼠肺组织内CTGF、phospho-ERK1/2蛋白表达均增加;与相应矽肺模型组相比,给予AcSDKP后,大鼠肺组织内CTGF、phospho-ERK1/2蛋白表达均明显降低.而各组间比较ERK1/2蛋白表达无明显改变.结论:AcSDKP可能通过阻断ERK1/2途径抑制了CTGF的表达,从而发挥抗矽肺纤维化的作用.     

碱性成纤维细胞生长因子和骨髓间充质干细胞构建的组织工程心脏瓣膜赖氨酰氧化酶的表达

目的 探讨碱性成纤维细胞生长因子(bFGF)和骨髓间充质干细胞(MSC)构建组织工程心脏瓣膜(TEHV)及其赖氨酰氧化酶(LOX)的表达.方法 贴壁培养法分离、培养和纯化大鼠MSC,取第3代种植于去细胞瓣叶支架上.分别将瓣叶置于含10 μg/L bFGF的培养液(A组)、普通培养液(B组)中构建TEHV,大鼠肌成纤维细胞构建的TEHV为C组,培养14 d后,采用Amplex red荧光法检测各组中的LOX蛋白含量,RT-PCR检测LOX mRNA表达.结果 B组的LOX蛋白含量和mRNA表达[(0.137±0.003)mg/L,2.08±0.03]高于A组[(0.124±0.002)mg/L,0.87±0.01]和C组[(0.127±0.002)mg/L,0.90±0.01](P<0.05),A、C两组差异无统计学意义(P>0.05).结论 bFGF可能通过降低MSC的LOX表达,使MSC构建的TEHV达到与肌成纤维细胞构建的类似.     

N-乙酰基-丝氨酰-天门冬酰-赖氨酰-脯氨酸对大鼠心脏成纤维细胞胶原蛋白合成及表达的调节作用

目的：探讨N-乙酰基-丝氨酰-天门冬酰-赖氨酰-脯氨酸(AcSDKP)对血小板衍生生长因子(PDGF)诱导的大鼠心脏成纤维细胞胶原合成的调节作用。方法：建立新生大鼠心脏成纤维细胞系;采用~3H-脯氨酸掺入法检测心脏成纤维细胞胶原蛋白的合成。采用Western印迹法检测心脏成纤维细胞Ⅰ、Ⅲ型胶原蛋白的表达。结果：PDGF对心脏成纤维细胞胶原蛋白合成的促进作用与浓度相关,并以10 ng/ml时最强。AcSDKP对PDGF介导的心脏成纤维细胞胶原合成有抑制作用,并且在10~(-9)mol/L时作用最强。结论：AcSDKP对PDGF介导的心脏成纤维细胞胶原合成有明显抑制作用,可能与其抗心脏纤维化的作用相关。     

共培养下后交叉韧带成纤维细胞中赖氨酰氧化酶的基因表达

背景：后交叉韧带对人膝关节结构的稳定以及功能的发挥起着重要作用。与内侧副韧带相比,损伤后的后交叉韧带难以很好的自我愈合,甚至会导致半月板撕裂和软骨损伤。为了提高后交叉韧带的愈合能力,这就需要寻找新的途径来再生和修复损伤的后交叉韧带。近年来的研究表明,赖氨酰氧化酶在组织损伤修复过程中起到非常重要的作用,但其在后交叉韧带修复过程中的分子机制研究尚未涉猎。 目的：观察与滑膜细胞共培养后交叉韧带成纤维细胞中赖氨酰氧化酶基因的表达。 方法：将第4代的后交叉韧带成纤维细胞和滑膜细胞分别种植于6孔板和Tanswell中。实验分为2组,即后交叉韧带成纤维细胞与滑膜细胞共培养组和后交叉韧带成纤维细胞单层培养组。培养6 h后,提取总RNA,通过半定量PCR和实时定量PCR检测单层培养组和共培养组中后交叉韧带成纤维细胞中赖氨酰氧化酶基因表达。 结果与结论：与单层培养组相比,赖氨酰氧化酶、赖氨酰氧化酶样蛋白1、赖氨酰氧化酶样蛋白2、赖氨酰氧化酶样蛋白3和赖氨酰氧化酶样蛋白4的基因表达在共培养的后交叉韧带细胞中都明显升高,分别增加了1.1,1.4,1.1,1.3,1.1倍(P < 0.05)。单层培养组家族成员在单层培养和共培养中表达情况的差异性,说明细胞之间的相互作用会影响后交叉韧带组织的损伤修复,对后交叉韧带损伤修复的机制研究有极其重要的参考价值。     

Distinct signalling pathways promote phagocytosis of bacteria, latex beads and lipopolysaccharide in medfly haemocytes

In insects, phagocytosis is an important innate immune response against pathogens and parasites, and several signal transduction pathways regulate this process. The focal adhesion kinase (FAK)/Src and mitogen activated protein kinase (MAPK) pathways are of central importance because their activation upon pathogen challenge regulates phagocytosis via haemocyte secretion and activation of the prophenoloxidase (proPO) cascade. The goal of this study was to explore further the mechanisms underlying the process of phagocytosis. In particular, in this report, we used flow cytometry, RNA interference, enzyme-linked immunosorbent assay, Western blot and immunoprecipitation analysis to demonstrate that (1) phagocytosis of bacteria (both Gram-negative and Gram-positive) is dependent on RGD-binding receptors, FAK/Src and MAPKs, (2) latex bead phagocytosis is RGD-binding-receptor-independent and dependent on FAK/Src and MAPKs, (3) lipopolysaccharide internalization is RGD-binding-receptor-independent and FAK/Src-independent but MAPK-dependent and (4) in unchallenged haemocytes in suspension, FAK, Src and extracellular signal-regulated kinase (ERK) signalling molecules participating in phagocytosis show both a functional and a physical association. Overall, this study has furthered knowledge of FAK/Src and MAPK signalling pathways in insect haemocyte immunity and has demonstrated that distinct signalling pathways regulate the phagocytic activity of biotic and abiotic components in insect haemocytes. Evidently, the basic phagocytic signalling pathways among insects and mammals appear to have remained unchanged during evolution.     

CTSB Knockdown Inhibits Proliferation and Tumorigenesis in HL-60 Cells

Background: Cathepsin B (CTSB) was well documented in solid tumors, up-regulated of CTSB expression is linked with progression of tumors. However, the study of CTSB in adult leukemia has not been reported. Methods: Total RNA was isolated from PBMC (peripheral blood mononuclear cell) of AML patients and healthy donors. qRT-PCR was performed to detect the expression of CTSB. The association of CTSB expression with the patients'' overall survival (OS) and disease-free survival (DFS) were analyzed. Stable HL-60 CTSB-shRNA cell lines were established by retrovirus infection and puromycin selection. Cell proliferation was detected by CCK-8 analysis. Tumorigenesis ability was analyzed by soft agar and xenograft nude mice model. Western blot was performed to detect the expression of CTSB and the proteins of cell signaling pathway. Results: The mRNA expression level of CTSB was up-regulated in AML patients compared to healthy control (p<0.001), and CTSB expression was significantly higher in M1, M2, M4 and M5 AML samples than healthy control. The CTSB expression in AML was associated with WBC count (p=0.037). Patients with high CTSB expression had a relatively poor OS (p=0.007) and a shorter DFS (p=0.018). Moreover, the expression level of CTSB may act as an independent prognostic factor for both OS (p=0.011) and DFS (p=0.004). Knockdown CTSB expression in HL-60 cells could inhibit the cells'' proliferation and tumorigeneses in vitro and in vivo. Further study showed knockdown CTSB expression in HL-60 cells could inactive the AKT signaling pathway. Conclusions: CTSB mRNA was upregulated in AML patients. CTSB overexpression was correlated with poor prognosis and may serve as an independent prognostic factor for both OS and DFS in AML patients. Knockdown CTSB expression in HL-60 cells could inhibit the cells'' proliferation and tumorigenesis. The underlying mechanism may be the inhibition of the AKT signaling pathway.     

转录因子Snail及黏附分子E-cadherin在胃癌中的表达及意义

目的探讨转录因子Snail及黏附分子E—cadherin在胃癌中的表达及意义。方法采用免疫组化sP法检测96例胃癌组织和80例癌旁组织中Snail、E—cadherin的表达,分析两者在不同组织类型与分化程度胃癌中的表达,以及与临床病理因素之间的关系。结果胃癌组织E—cadherin的阳性率（37．5％）显著低于癌旁组织（100％）（P〈0．05）,E—cadherin的表达与胃癌不同分化程度、组织学类型、浸润深度、淋巴结转移、临床分期及远处转移有关（P〈0．05）。胃癌组织Snail阳性率（83．3％）显著高于癌旁组织（41．25％）（P〈0．05）,Snail的表达与胃癌不同分化程度、组织学类型、浸润深度、淋巴结转移及远处转移有关（P〈0．05）。胃癌组织中E—cadherin与Snail的表达呈负相关（P〈0．05）。结论E—cadherin蛋白低表达与Snail蛋白高表达可能是胃黏膜恶性转变以及胃癌发生浸润转移的重要生物学标志。联合检测E—cadherin及Snail对预测胃癌浸润转移有重要意义。     

Cyclooxygenase-2 Expression Is Related to the Epithelial-to-Mesenchymal Transition in Human Colon Cancers

Purpose

Down-regulation of E-cadherin is a hallmark of the epithelial-to-mesenchymal transition (EMT). EMT progression in cancer cells is associated with the loss of certain epithelial markers and the acquisition of a mesenchymal phenotype, as well as migratory activities. Cyclooxygenase-2 (COX-2) expression is associated with tumor invasion and metastasis in colon cancer. This study investigated the relationship between E-cadherin and COX-2 in colon cancer cells and human colon tumors.

Materials and Methods

Colon cancer cell lines and immunohistochemistry were used.

Results

E-cadherin expression was inversely related to the expressions of COX-2 and Snail in colon cancer cells. Ectopic expression of COX-2 or Snail reduced E-cadherin and induced a scattered, flattened phenotype with few intercellular contacts in colon cancer cells. Treatment of cancer cells with phorbol 12-myristate 13-acetate increased the expressions of COX-2 and Snail, decreased 15-hydroxyprostaglandin dehydrogenase expression, and increased the cells'' motility. In addition, exposure to prostaglandin E₂ increased Snail expression and cell motility, and decreased E-cadherin expression. Membranous E-cadherin expression was lower in adenomas and cancers than in the adjacent, non-neoplastic epithelium. In contrast, the expressions of Snail and COX-2 were higher in cancers than in normal tissues and adenomas. The expressions of COX-2 and Snail increased in areas with abnormal E-cadherin expression. Moreover, COX-2 expression was related to higher tumor stages and was significantly higher in nodal metastatic lesions than primary cancers.

Conclusion

This study suggests that COX-2 may have a role in tumor metastasis via EMT.     

肿瘤发生的潜在分子基础(2)

肿瘤发生是一个多步骤过程.绝大多数人肿瘤由产生了系列相继变化的单一细胞形成.这些变化导致细胞有丝分裂信号或生长控制的细微异常,逐步赋予细胞赘生的特性,直至细胞形成恶性肿瘤.防御肿瘤发生的一个重要机能是诱导细胞死亡,这种机能持续不断地清除机体内多余的,受损的或变异的细胞.对肿瘤细胞增殖优势的分子机理的认识,揭示了许多肿瘤细胞如何应答异常有丝分裂信号的内在现象,而蛋白磷酸激酶是介导这些信号通路的主体.天然细胞或病毒蛋白能作为细胞死亡效应子发挥作用,尤其有意义的是,有些细胞和病毒蛋白具有肿瘤特异性细胞死亡效应,可望发展成为新的抗肿瘤治疗制剂.     

Src Tyrosine Kinase Inhibitor,M475271, Suppresses Subcutaneous Growth and Production of Lung Metastasis Via Inhibition of Proliferation,Invasion, and Vascularization of Human Lung Adenocarcinoma Cells

Src, a proto-oncogene, has been strongly implicated in the growth, progression and metastasis of a number of human cancers. Its role in lung cancer is, however, still unknown. In the present study, we assessed the expression of Src in three different human lung adenocarcinoma cell lines (PC-9, PC14PE6, A549), and explored the effect of a novel Src kinase inhibitor, M475271, on the behavior of the cell lines. The three cell lines expressed various levels of auto-phosphorylated Src. While M475271 reduced Src-phosphorylation and invasiveness of all three cell lines, it inhibited the proliferation of PC-9 and A549 cells with highly phosphorylated Src, but not PC14PE6 cells. We further examined the effect of M475271 on subcutaneous tumors and lung metastasis caused by PC-9 and/or A549 cells in NK-cell depleted SCID mice. Daily oral treatment with M475271 inhibited the growth of subcutaneous tumors with PC-9 and A549 cells via inhibition of tumor cells proliferation, VEGF production and/or vascularization in the mice in a dose-dependent manner. In the metastasis model with A549 cells, the lung weight in the M475271 (50 mg/kg)-treated group was less than that of the control group, despite no difference in the number of metastatic nodules. Our results suggest that inhibition of tyrosine kinase Src by M475271 could reduce the growth, invasion and VEGF-mediated neovascularization of lung adenocarcinoma cells, resulting in inhibition of growth of subcutaneous tumors and lung metastasis. Therefore, a novel Src tyrosine kinase inhibitor, M475271, might be helpful for controlling the progression of human lung adenocarcinoma.     

EphA2调控结直肠癌细胞耐药的初步研究

目的:探究Eph受体A2(Eph A2)在结直肠癌细胞化疗耐药中的作用及相关机制。方法:Western blot及real-time PCR检测人结肠癌细胞株Lo Vo及结肠癌耐药细胞株Lo Vo/5-FU中Eph A2的表达情况。转染Eph A2 siRNA干扰结肠癌耐药细胞株Lo Vo/5-FU中Eph A2的表达,CCK-8法检测细胞对化疗药物的敏感性,划痕实验及Transwell实验检测细胞迁移及侵袭能力的变化,Western blot检测上皮-间充质转化(EMT)及相关信号通路分子的蛋白水平。结果:耐药细胞株Lo Vo/5-FU中Eph A2的mRNA及蛋白表达水平均明显高于亲本细胞株(P0.05);并且在亲本细胞株Lo Vo中,Eph A2的蛋白表达水平随着5-FU浓度的增加有升高趋势。沉默Eph A2可降低结肠癌耐药细胞株Lo Vo/5-FU的细胞活力,增加其对化疗药物的敏感性,并抑制细胞的侵袭迁移;同时上调细胞中上皮细胞标志物E-cadherin和β-catenin的表达并下调间充质细胞标志物N-cadherin和vimentin的表达,可抑制结肠癌耐药细胞株Lo Vo/5-FU的EMT进程。此外,干扰Eph A2的表达之后,Notch和Snail的表达也明显降低。结论:沉默Eph A2可部分恢复结肠癌耐药细胞株Lo Vo/5-FU对化疗药物的敏感性,其机制可能与抑制细胞侵袭和迁移、同时通过Notch/Snail信号通路影响细胞的EMT进程有关。     

Hyaluronan synthase 2 overexpression is correlated with the tumorigenesis and metastasis of human breast cancer

Extracellular matrix (ECM) is closely correlated with the malignant behavior of breast cancer cells. Hyaluronan (HA) is one of the main components of ECM, and actively regulates cell adhesion, migration and proliferation by interacting with specific cell surface receptors such as CD44 and RHAMM. HA synthase 2 (HAS2) catalyzes the sysnthesis of HA, but its role in breast tumorigenesis remains unclear. This study assessed the roles of HAS2 in malignant behavior of human breast cancer and sought to provide mechanistic insights into the biological and pivotal roles of HAS2. We observed HAS2 was overexpressed in breast cancer cell lines and invasive duct cancer tissues, compared with the nonmalignant breast cell lines and normal breast tissues. In addition, a high level of HAS2 expression was statistically correlated with lymph node metastasis. Functional assays showed that knockdown of HAS2 expression inhibited breast tumor cell proliferation in vivo and in vitro, through the induction of apoptosis or cell cycle arrest. Further studies showed that the HA were elevated in breast cancer, and HAS2 could upregulate HA expression. In conclusion, HAS2-HA system influences the biological characteristics of human breast cancer cells, and HAS2 may be a potential prognostic marker and therapeutic target in breast cancer.     

宫颈癌组织中PTEN和COX-2的表达与侵袭转移的关系

目的探讨宫颈癌组织中PTEN和COX-2的表达与侵袭转移的关系。方法采用免疫组化SP法检测68例宫颈癌组织中PTEN和COX-2的表达情况。结果 PTEN在宫颈癌组织中阳性表达率明显低于正常宫颈组织,差异有统计学意义（P〈0.01）,且与淋巴结转移显著相关（P〈0.05）;而COX-2阳性表达率显著高于正常宫颈组织（P〈0.01）,与淋巴结转移显著相关（P〈0.05）;在癌组织中PTEN和COX-2表达呈负相关。结论PTEN和COX-2的异常表达与宫颈癌的发生、发展及淋巴结转移密切相关,两者共同参与了宫颈癌发生和侵袭转移。