三氧化二砷对胶质瘤U251细胞侵袭迁移和MMP2表达的影响

目的:研究三氧化二砷(As2O3)在体外对胶质瘤U251细胞侵袭迁移及金属基质蛋白酶2(MMP2)表达的影响。方法:采用台盼兰法(MTT法)观察As2O3对U251细胞粘附能力的影响;Transwell侵袭小室测定法检测As2O3对U251细胞侵袭能力的影响;明胶酶谱实验和逆转录-聚合酶链反应(RT-PCR)方法观察As2O3对金属基质蛋白酶2(Matrix metalloproteinase2,MMP2)在U251细胞中表达的影响。结果:As2O3能够降低U251细胞粘附能力,Transwell实验中药物处理组穿膜细胞数明显低于对照组(P<0.01),As2O3不但降低MMP2前体蛋白的表达,而且影响其mRNA的表达。结论:As2O3能够有效抑制胶质瘤U251细胞的侵袭迁移,其作用机制可能与As2O3下调胶质瘤U251细胞中MMP2的表达有关。     

三氧化二砷对胶质瘤U251细胞侵袭迁移和MMP2表达的影响

目的:研究三氧化二砷(As2O3)在体外对胶质瘤U251细胞侵袭迁移及金属基质蛋白酶2(MMP2)表达的影响.方法:采用台盼兰法(MTT法)观察As2O3对U251细胞粘附能力的影响;Transwell侵袭小室测定法检测As2O3对U251细胞侵袭能力的影响;明胶酶谱实验和逆转录-聚合酶链反应(RT-PCR)方法观察As2O3对金属基质蛋白酶2(Matrix metalloproteinase2,MMP2)在U251细胞中表达的影响.结果:As2O3能够降低U251细胞粘附能力,Transwell实验中药物处理组穿膜细胞数明显低于对照组(P＜0.01),As2O3不但降低MMP2前体蛋白的表达,而且影响其mRNA的表达.结论:As2O3能够有效抑制胶质瘤U251细胞的侵袭迁移,其作用机制可能与As2O3下调胶质瘤U251细胞中MMP2的表达有关.     

核受体PXR对人结肠癌细胞增殖和化疗敏感性的影响

目的:探讨核受体PXR在结肠癌细胞增殖和化疗敏感性中的作用.方法:分别用RT-PCR和westernblot方法检测PXR在人结肠癌细胞株LS174T、LOVO、HT29、HCT116中的表达情况.通过质粒稳定转染方法建立PXR敲低的细胞株.用MTT方法分析利福平活化PXR或稳定转染敲低PXR后,细胞增殖和化疗敏感性的改变.结果:在结肠癌细胞株LS174T、LOVO、HT29、HCT116中,LS174T细胞的PXR表达水平最高.利福平处理后,LS174T细胞中PXR表达增强.利福平活化PXR或稳定转染敲低PXR后,相应地促进或抑制细胞增殖,降低或提高细胞对化疗药物的敏感性.结论:PXR能促进结肠癌细胞增殖,提高细胞对化疗药物的敏感性,可能在结肠癌多药耐药机制中具有重要作用.     

敲低HSP60 对结肠癌SW480 细胞增殖能力的影响及其机制探究

目的:研究热休克蛋白60(HSP60)敲低对结肠癌SW480细胞增殖的影响,并进一步探究其作用机制。方法:通过含HSP60sh RNA载体的慢病毒感染加上流式细胞仪无菌分选的方法构建结肠SW480 HSP60基因稳定RNA干扰(RNAi)单克隆细胞系,利用Western blot和q-PCR验证结肠癌细胞中HSP60的敲低效率;使用CCK-8试剂检测结肠癌细胞增殖能力,并用流式细胞仪检测其HSP60敲低对细胞周期的影响。结果:Western blot和q-PCR结果验证了HSP60在结肠癌细胞中的敲低效率,与对照组细胞相比,实验组细胞HSP60的m RNA水平和蛋白水平均降低了60%以上。CCK-8实验结果表明,敲低HSP60后SW480细胞的增殖能力下降了约70%;流式细胞周期实验显示敲低HSP60后SW480细胞中G0/G1期、S期、G2/M期的分布比例变化不大。结论:敲低HSP60能够显著抑制SW480细胞的增殖能力,而SW480细胞周期并没有发生明显变化,推测HSP60的敲低引起的线粒体损伤导致细胞生长速度变慢。     

肿瘤坏死因子样弱凋亡诱导因子对人肝星状细胞生物学行为的影响

目的:观察肿瘤坏死因子样弱凋亡诱导因子(TWEAK)对人肝星状细胞(HSCs)株LX-2增殖、细胞周期、细胞凋亡、迁移及粘附能力的影响。方法:用不同浓度TWEAK培养LX-2细胞24或48 h,采用CCK-8法检测TWEAK对LX-2细胞增殖的影响,流式细胞术检测TWEAK对LX-2细胞周期和凋亡的影响,Transwell小室检测TWEAK对LX-2细胞迁移能力的影响,Matrigel基质胶检测TWEAK对LX-2细胞的粘附能力的影响。结果:与对照组相比,40 ng/m L和100 ng/m L TWEAK都能使LX-2细胞的迁移能力增强(P0.05),且100 ng/m L较40 ng/m L作用更强(P0.01);100 ng/m L TWEAK能够明显抑制LX-2细胞的粘附能力(P0.0001);40 ng/m L、100 ng/m L TWEAK对LX-2细胞的增殖、周期及凋亡无明显影响(P0.05)。结论:TWEAK能够增强LX-2细胞迁移能力,抑制其粘附能力。     

胰蛋白酶诱导人脐静脉内皮细胞分泌白细胞介素-8

目的:研究胰蛋白酶对IL-8释放的影响。方法:分离、培养人脐静脉内皮细胞(human umbilical vein endothelial cells,HUVECs)、倒置显微镜观察形态变化,流式细胞术检测内皮细胞标志和蛋白酶活化受体-2(proteinase-activated receptor-2,PAR-2)表达,ELISA检测HUVECs培养上清中IL-8水平。结果:HUVECs表达内皮细胞标志和PAR-2。刺激16 h,1 g/ml胰蛋白酶和100M PAR-2激活肽组HUVECs单层均匀性降低。胰蛋白酶能够显著刺激HUVECs释放IL-8,PAR-2激活肽也诱导IL-8水平升高。蛋白酶抑制剂和PAR-2抑制肽均能够显著抑制胰蛋白酶诱导的IL-8释放。PAR-2激活肽和胰蛋白酶诱导升高的IL-8水平之间成正相关性。结论:胰蛋白酶很可能通过PAR-2激活促进血管内皮细胞释放IL-8。     

NOD1配体抑制人早孕期滋养细胞的侵袭功能

目的:明确固有免疫受体NOD1对人早孕期滋养细胞侵袭功能的调控及对侵袭相关因子分泌的影响。方法:采用免疫细胞化学法鉴定原代滋养细胞NOD1的表达,用transwell侵袭实验检测激活NOD1后滋养细胞侵袭功能的改变,ELISA检测配体刺激后滋养细胞MMP2和MMP9的分泌情况。结果:免疫细胞化学结果显示滋养细胞分离鉴定成功,且原代滋养细胞可以表达固有免疫受体NOD1。使用NOD1的特异性配体及非特异性配体,发现激活NOD1可以抑制滋养细胞的侵袭,且非特异性配体LPS可以下调侵袭相关金属基质蛋白酶分子MMP2和MMP9的分泌,特异性配体i E-DAP仅下调MMP9的分泌而对MMP2的分泌无影响。结论:固有免疫模式识别受体NOD1可以在早孕期滋养细胞表达,可调控滋养细胞的侵袭功能,其激活会导致侵袭相关分子MMP2和MMP9的分泌下降。     

口腔角质形成细胞与成纤维细胞共培养对胶原代谢的影响

目的:了解口腔角质形成细胞与成纤维细胞共同培养对胶原代谢的影响.方法:对口腔粘膜角质形成细胞和成纤维细胞进行了共培养,检测其胶原分泌水平、基质金属蛋白酶的含量及活性、基质金属蛋白酶抑制剂的水平.结果:只有共同培养组才能检测到MMP-9;共同培养组的活化型MMP-2水平与单独培养组相比无显著差异.角质形成细胞与成纤维细胞共同培养组的TIMP-1水平及胶原水平均明显高于单独培养组.结论:口腔角质形成细胞与成纤维细胞共同培养可能主要通过改变基质金属蛋白酶抑制剂的水平而影响胶原代谢.     

尿激酶受体研究进展

细胞表面的尿激酶受体是一种高度糖基化的蛋白质,通过糖基磷脂酰肌醇锚定在细胞膜上。尿激酶受体除能与尿激酶或尿激酶原结合外还与玻连蛋白,整合素,α2巨球蛋白受体—低密度脂蛋白相关蛋白等相互作用。细胞表面的尿激酶受体不仅能促进纤溶酶原的激活、细胞外基质的降解,一些生长因子的释放或活化,而又还参与细胞粘附以及尿激酶／纤溶酶原激活物抑制剂复合物的代谢和细胞迁移。在肿瘤患血液中可溶性尿激酶受体含量显高于正常人,因而对尿激酶受体含量的测定可作为临床肿瘤诊断的指标。动物实验结果表明,阻断尿激酶与尿激酶受体的结合或抑制尿激酶受体的表达可显抑制肿瘤的浸润及转移。     

疏肝养血降乳汤含药血清对垂体瘤增殖和凋亡作用的解析

为了探索疏肝养血降乳汤含药血清对垂体瘤(垂体泌乳素腺瘤)细胞增殖和凋亡的影响及其作用机制,采用大鼠垂体瘤细胞系MMQ作为研究对象,通过MTT法检测不同浓度疏肝养血降乳汤含药血清对MMQ细胞活力的影响;流式细胞仪检测不同浓度疏肝养血降乳汤含药血清对MMQ细胞周期和凋亡的影响;蛋白质免疫印迹检测不同浓度疏肝养血降乳汤含药血清对MMQ细胞Caspase-1、Caspase-3蛋白剪切活化的影响。表明,疏肝养血降乳汤含药血清对MMQ细胞增值有很强的抑制作用,通过激活Caspase-1、Caspase-3而促进MMQ细胞的凋亡,含药血清将MMQ细胞阻滞在G2/M期。这些说明疏肝养血降乳汤含药血清能够抑制MMQ细胞增值并促进其凋亡。     

PAR1-mediated RhoA activation facilitates CCL2-induced chemotaxis in PC-3 cells

Patients with advanced prostate cancer often exhibit increased activation of the coagulation system. The key activator of the coagulation cascade is the serine protease thrombin which is capable of eliciting numerous cellular responses. We previously reported that the thrombin receptor PAR1 is overexpressed in prostate cancer. To investigate further the role of PAR1 in prostate cancer metastasis, we examined the effects of thrombin activation on cell adhesion and motility in PC-3 prostate cancer cells. Activation of PAR1-induced dynamic cytoskeletal reorganization and reduced PC-3 binding to collagen I, collagen IV, and laminin (P < 0.01) but not fibronectin. Expression of the cell surface integrin receptors did not change as assessed by flow cytometry. Immunofluorescence microscopy revealed that PAR1 stimulation caused reorganization of the focal adhesions, suggesting that PAR1 activation in PC-3 cells may be modulating cell adhesion through integrin function but not expression. Furthermore, RhoA was activated upon stimulation with thrombin with subsequent cell contraction, decreased cell adhesion, and induced migration towards monocyte chemoattractant protein 1 (MCP-1; CCL2). Thus, it appears that thrombin stimulation plays a role in prostate cancer metastasis by decreasing cell adhesion to the extracellular matrix and positioning the cell in a "ready state" for migration in response to a chemotactic signal. Further exploration is needed to determine whether PAR1 activation affects other signaling pathways involved in prostate cancer.     

蛋白酶活化受体1在凝血酶介导的肺癌细胞功能中的作用

目的:探讨蛋白酶活化受体1(PAR1)在凝血酶促进肺癌细胞迁移、黏附、克隆形成及胶原收缩中的作用。方法:将本实验室已构建的重组干扰载体pSilence-shPAR1和过表达载体pIRES-EGFP-PAR1分别转入人肺癌细胞PLA-801D和PLA-801C中,采用反转录PCR和实时荧光定量PCR方法检测细胞中PAR1的表达量,Transwell实验检测细胞的迁移能力,细胞黏附实验检测细胞对细胞外基质的黏附能力,克隆形成实验检测细胞的增殖能力,胶原收缩实验评价细胞对细胞外基质的重塑能力。结果:PAR1高表达(PLA-801C-pIRES-EGFP-PAR1)可明显增强PLA-801C细胞的迁移、黏附和胶原收缩能力(P<0.05,P<0.001),而PAR1被有效干扰后(PLA-801D-pSi lence-shPAR1),PLA-801D细胞的迁移、黏附和胶原收缩能力显著减弱(P<0.05,P<0.001),而且PAR1的表达量直接与PLA-801D和PLA-801C细胞的克隆形成能力呈正相关。结论:PAR1在凝血酶促进肺癌细胞的黏附、迁移增殖和细胞外基质重塑等功能中发挥着重要作用,为以PAR1为靶的抗肿瘤治疗提供了理论基础。     

ADAM and ADAMTS family proteins and their role in the colorectal cancer etiopathogenesis

The ADAM and ADAMTS families, also called adamalysins belong to an important group of extracellular matrix proteins. The ADAMs family belong to both the transmembrane and secreted proteins, while ADAMTS family only contains secreted forms. Adamalysins play an important role in the cell phenotype regulation via their activities in signaling pathways, cell adhesion and migration. The human proteome contains 21 ADAM, and 19 ADAMTS proteins, which are involved in extracellular matrix remodeling, shedding of various substrates such as: adhesion ligands, growth factors, their receptors and diverse cytokines. Recent studies provide evidence that adamalysins play a crucial role in colorectal cancer (CRC) etiopathogenesis. It seems possible that adamalysins might be used as CRC prediction markers or potential pharmaceutical targets. [BMB Reports 2013; 46(3): 139-150]     

Increased Expression of Protease-Activated Receptor 4 and Trefoil Factor 2 in Human Colorectal Cancer

Protease-activated receptor 4 (PAR4), a member of G-protein coupled receptors family, was recently reported to exhibit decreased expression in gastric cancer and esophageal squamous cancer, yet increased expression during the progression of prostate cancer. Trefoil factor 2 (TFF2), a small peptide constitutively expressed in the gastric mucosa, plays a protective role in restitution of gastric mucosa. Altered TFF2 expression was also related to the development of gastrointestinal cancer. TFF2 has been verified to promote cell migration via PAR4, but the roles of PAR4 and TFF2 in the progress of colorectal cancer are still unknown. In this study, the expression level of PAR4 and TFF2 in colorectal cancer tissues was measured using real-time PCR (n = 38), western blotting (n=38) and tissue microarrays (n = 66). The mRNA and protein expression levels of PAR4 and TFF2 were remarkably increased in colorectal cancer compared with matched noncancerous tissues, especially in positive lymph node and poorly differentiated cancers. The colorectal carcinoma cell LoVo showed an increased response to TFF2 as assessed by cell invasion upon PAR4 expression. However, after intervention of PAR4 expression, PAR4 positive colorectal carcinoma cell HT-29 was less responsive to TFF2 in cell invasion. Genomic bisulfite sequencing showed the hypomethylation of PAR4 promoter in colorectal cancer tissues and the hypermethylation in the normal mucosa that suggested the low methylation of promoter was correlated to the increased PAR4 expression. Taken together, the results demonstrated that the up-regulated expression of PAR4 and TFF2 frequently occurs in colorectal cancer tissues, and that overexpression of PAR4 may be resulted from promoter hypomethylation. While TFF2 promotes invasion activity of LoVo cells overexpressing PAR4, and this effect was significantly decreased when PAR4 was knockdowned in HT-29 cells. Our findings will be helpful in further investigations into the functions and molecular mechanisms of Proteinase-activated receptors (PARs) and Trefoil factor factors (TFFs) during the progression of colorectal cancer.     

Activation of proteinase-activated receptor 1 promotes human colon cancer cell proliferation through epidermal growth factor receptor transactivation

Serine proteases are now considered as crucial contributors to the development of human colon cancer. We have shown recently that thrombin is a potent growth factor for colon cancer cells through activation of the aberrantly expressed protease-activated receptor 1 (PAR1). Here, we analyzed the signaling pathways downstream of PAR1 activation, which lead to colon cancer cell proliferation in HT-29 cells. Our data are consistent with the following cascade of events on activation of PAR1 by thrombin or specific activating peptide: (a) a matrix metalloproteinase-dependent release of transforming growth factor-alpha (TGF-alpha) as shown with TGF-alpha blocking antibodies and measurement of TGF-alpha in culture medium; (b) TGF-alpha-mediated activation of epidermal growth factor receptor (EGFR) and subsequent EGFR phosphorylation; and (c) activation of extracellular signal-regulated protein kinase 1/2 (ERK1/2) and subsequent cell proliferation. The links between these events are shown by the fact that stimulation of cell proliferation and ERK1/2 on activation of PAR1 is reversed by the MMP inhibitor batimastat, TGF-alpha neutralizing antibodies, EGFR ligand binding domain blocking antibodies, and the EGFR tyrosine kinase inhibitors AG1478 and PD168393. Therefore, transactivation of EGFR seems to be a major mechanism whereby activation of PAR1 results in colon cancer cell growth. Finally, PAR1 activation induces Src phosphorylation, which is reversed by using the Src tyrosine kinase inhibitor PP2, suggesting that Src activation plays a permissive role for PAR1-mediated ERK1/2 activation and cell proliferation probably acting downstream of the EGFR. These data explain how thrombin exerts robust trophic action on colon cancer cells and underline the critical role of EGFR transactivation.     

The molecular and clinical role of Tensin 1/2/3 in cancer

Tensin 1 was originally described as a focal adhesion adaptor protein, playing a role in extracellular matrix and cytoskeletal interactions. Three other Tensin proteins were subsequently discovered, and the family was grouped as Tensin. It is now recognized that these proteins interact with multiple cell signalling cascades that are implicated in tumorigenesis. To understand the role of Tensin 1–3 in neoplasia, current molecular evidence is categorized by the hallmarks of cancer model. Additionally, clinical data involving Tensin 1–3 are reviewed to investigate the correlation between cellular effects and clinical phenotype. Tensin proteins commonly interact with the tumour suppressor, DLC1. The ability of Tensin to promote tumour progression is directly correlated with DLC1 expression. Members of the Tensin family appear to have tumour subtype-dependent effects on oncogenesis; despite numerous data evidencing a tumour suppressor role for Tensin 2, association of Tensins 1–3 with an oncogenic role notably in colorectal carcinoma and pancreatic ductal adenocarcinoma is of potential clinical relevance. The complex interplay between these focal adhesion adaptor proteins and signalling pathways are discussed to provide an up to date review of their role in cancer biology.     

Protease-activated receptor 2 in colon cancer: trypsin-induced MAPK phosphorylation and cell proliferation are mediated by epidermal growth factor receptor transactivation

Several lines of evidence suggest that tumor-derived trypsin contributes to the growth and invasion of cancer cells. We have recently shown that trypsin is a potent growth factor for colon cancer cells through activation of the G protein-coupled receptor protease-activated receptor 2 (PAR2). Here, we analyzed the signaling pathways downstream of PAR2 activation that lead to colon cancer cell proliferation in HT-29 cells. Our data are consistent with the following cascade of events upon activation of PAR2 by the serine protease trypsin or the specific PAR2-activating peptide (AP2): (i) a matrix metalloproteinase-dependent release of transforming growth factor (TGF)-alpha, as demonstrated with TGF-alpha-blocking antibodies and measurement of TGF-alpha in culture medium; (ii) TGF-alpha-mediated activation of epidermal growth factor receptor (EGF-R) and subsequent EGF-R phosphorylation; and (iii) activation of ERK1/2 and subsequent cell proliferation. The links between these events are demonstrated by the fact that stimulation of cell proliferation and ERK1/2 upon activation of PAR2 is reversed by the metalloproteinase inhibitor batimastat, TGF-alpha-neutralizing antibodies, EGF-R ligand binding domain-blocking antibodies, and the EGF-R tyrosine kinase inhibitors AG1478 and PD168393. Therefore, transactivation of EGF-R appears to be a major mechanism whereby activation of PAR2 results in colon cancer cell growth. By using the Src tyrosine kinase inhibitor PP2, we further showed that Src plays a permissive role for PAR2-mediated ERK1/2 activation and cell proliferation, probably acting downstream of the EGF-R. These data explain how trypsin exerts robust trophic action on colon cancer cells and underline the critical role of EGF-R transactivation.     

CD155 knockdown promotes apoptosis via AKT/Bcl‐2/Bax in colon cancer cells

CD155, one of the nectin‐like molecule family members, is involved in cell adhesion and motility. CD155 is overexpressed in several human cancers, but its role in proliferation and apoptosis of colorectal cancer remains unclear. We found that CD155 was up‐regulated in colorectal cancer tissues. CD155 knockdown via shRNA lentiviruses inhibited colon cancers cell migration and invasion, with a reduction in the expression of FAK, Src and MMP‐2. CD155 down‐regulation also suppressed colon cancer cell proliferation, accompanied by changing expressions of some molecules related to cell cycle. Finally, CD155 knockdown increased the expression ratio between Bax and Bcl‐2, resulting in a significant increase in colon cancer cell apoptosis. Taken together, these results demonstrate that CD155 is involved in not only migration and invasion but also proliferation and survival abilities of colon cancer cells, suggesting that CD155 is one of key molecules promoting the growth and metastasis of colorectal cancer.     

Ito Cell Morphology, α-smooth Muscle Actin and Collagen Type IV Expression in the Liver of Patients with Gastric and Colorectal Tumors

The alteration in sinusoidal collagen type IV occurrence, and myofibroblastic (α-SMA-positive) Ito cellular transformation are described in the liver of patients with malignant gastric and colorectal tumors, using electron microscopy as well as light microscopical and ultrastructural immunohistochemistry. The ultrastructural finding revealed transformation of Ito cells mostly into transitional cells in highly differentiated primary tumors and into transitional and myofibroblast-like cells with expressed changes in the other sinusoidal cells in poorly differentiated tumors. Ito cell numbers increased significantly in the livers of cancer patients. A highly significant statistical association was obtained between Ito cell numbers on the one hand and collagen type IV and α-SMA immunoreactivity on the other hand in the pericentral zone of the liver lobule. Ultrastructural immunohistochemistry showed increased collagen IV immune deposits in the space of Disse, assembled for the most part around and inside transitional cells. α-SMA immunoreactivity was detected in activated Ito cells diffuse in the lobule, with stronger expression in the intermediate and pericentral zones. It is suggested that stimuli which can influence Ito cell transformation are produced by tumor cells from the primary tumor (TGF-β1, TNF-α, PDGF-β etc.) and from the metastasizing gastric or colorectal tumor cells – matrix metalloproteinase-2 (MMP-2). It is suggested that sinusoidal extracellular matrix deterioration creates a barrier for cancer invasion on the one hand, or possibly facilitates metastasizing by ensurance of matrix for adhesion on the other hand.     

Pancreatic cancer cells invasiveness is mainly affected by interleukin-1beta not by transforming growth factor-beta1

BACKGROUND: We investigated in vitro whether IL-1beta and TGF-beta1 affect pancreatic cancer cell growth, adhesion to the extracellular matrix and Matrigel invasion. MATERIALS AND METHODS: Adhesion to fibronectin, laminin and type I collagen, and Matrigel invasion after stimulation with saline, IL-1beta and TGF-beta1 were evaluated using three primary and three metastatic pancreatic cancer cell lines. RESULTS: Extracellular matrix adhesion of control cells varied independently of the metastatic characteristics of the studied cell lines, whereas Matrigel invasion of control cells was partly correlated with the in vivo metastatic potential. IL-1beta did not influence extracellular matrix adhesion, whereas it significantly enhanced the invasiveness of three of the six cell lines. TGF-beta1 affected the adhesion of one cell line, and exerted contrasting effects on Matrigel invasion of different cell lines. CONCLUSIONS: IL-1beta enhances the invasive capacity of pancreatic cancer cells, whereas TGF-beta1 has paradoxical effects on pancreatic cancer cells; this makes it difficult to interfere with TGF-beta1 signaling in pancreatic cancer treatment.