Effects of ulinastatin and docetaxel on breast cancer invasion and expression of uPA,uPAR and ERK

Objective

To investigate the effects of ulinastatin and docetaxel on invasion of breast cancer cells and expression of uPA, uPAR and ERK, breast cancer MDA-MB-231 and MCF-7 cells.

Methods

The nude mice were treated with PBS, ulinastatin, docetaxel, and ulinastatin plus docetaxel, respectively. Their effects on 1) cell invasion ability was assayed using Transwell; 2) expression of uPA, uPAR and ERK was detected by real time PCR and Western blot; 3) uPA, uPAR and p-ERK protein level in nude mice was quantified by immunohistochemistry.

Results

1) Treatment with ulinastatin, docetaxel, and ulinastatin plus docetaxel, respectively, significantly inhibited MDA-MB-231 and MCF-7 cell invasion; 2) mRNA and protein levels of uPA, uPAR and ERK1/2 were inhibited by ulinastatin, but enhanced by docetaxel.

Conclusion

Ulinastatin can enhance the effects of docetaxel on invasion of breast cancer cells. And that uPA, uPAR and p-ERK expression is obviously inhibited by ulinastatin.     

LIM kinase 1 increases tumor metastasis of human breast cancer cells via regulation of the urokinase-type plasminogen activator system

Mammalian LIM kinase 1 (LIMK1) phosphorylates and inactivates the actin-binding and -depolymerizing factor cofilin and induces actin cytoskeletal changes. LIMK1 is reported to play an important role in cell motility, but the mechanism of induction of cell motility and the role of LIMK1 in tumor growth, angiogenesis and invasion are poorly understood. Here we show that expression of LIMK1 in MDA-MB-435 human breast cancer cells enhanced cell proliferation and cell invasiveness and promoted in vitro angiogenesis. Since tumor metastasis requires degradation of the extracellular matrix by the serine protease urokinase type plasminogen activator (uPA), we examined the role of LIMK1 in the regulation of uPA/uPAR system. LIMK1 overexpression in breast cancer cells upregulated the uPA system, increased uPA promoter activity, induced uPA and uPAR mRNA and protein expression and induced uPA secretion. In contrast, cells transfected with the catalytically inactive LIMK mutant D460N-LIMK1 did not exhibit these phenotypic changes. Blocking antibodies against uPA and uPAR suppressed LIMK1-induced cell invasiveness. In addition, LIMK1 overexpression increased tumor growth in female athymic nude mice, promoted tumor angiogenesis and induced metastasis to livers and lungs, possibly by increasing uPA expression in the tumors. Finally, LIMK1 and uPAR were coordinately overexpressed in human breast tumors. These results suggested an important role for LIMK1 signaling in breast cancer tumor growth, angiogenesis and invasion and a regulatory connection between LIMK1 and the uPA system.     

尿激酶氨基末端基因抗乳腺癌细胞转移的实验研究

目的：探讨尿激酶氨基末端（ATF）基因转移对肿瘤转移的抑制作用。方法：构建重组ATF基因真核表达载体pcDNA3-ATF,用脂质体Lipofectin介导,将其导入其证明尿激酶（uPA)和尿激酶受体（uPAR）均有表达的人乳腺癌细胞系MCF－7,用Western blot检测转染细胞ATF基因的表达,体外观察并比较了野生型和转基因MCF－7细胞侵袭人工基底膜能力;裸鼠皮下接种癌细胞,复制自发性肿瘤转移模型,观察成瘤性和转移性。结果uPA／uPAR在MCF－7中有较高水平的表达;转ATF基因后,可检测到ATF的明显表达,体外侵袭穿透人工基底膜的能力明显降低,体内原位成瘤性不受影响,但自主性体肺转移能力有一定程度的下降,结论ATF基因转移后,ATF的表达可能竞争 抑制内源性uPA与uPAR的结合,在一定程度上抑制癌细胞的侵袭和转移。     

Macrophage inhibitory cytokine-1 induces the invasiveness of gastric cancer cells by up-regulating the urokinase-type plasminogen activator system

In our search for genes associated with gastric cancer progression, we identified macrophage inhibitory cytokine-1 (MIC-1), a member of the transforming growth factor beta superfamily, as an overexpressed gene in gastric tumor tissues. Expression analysis of MIC-1 in gastric tumor tissues revealed a specific expression in gastric cancer cells, and this expression level was well correlated with invasive potential in various human gastric cancer cell lines. Stable transfection of MIC-1 into SNU-216, a human gastric cancer cell line, significantly increased its invasiveness. The overexpression of MIC-1 into SNU-216 cells significantly increased the activity of urokinase-type plasminogen activator (uPA), and the expressions of uPA and urokinase-type plasminogen activator receptor (uPAR). Similarly, the stimulation of gastric cancer cell lines with purified recombinant MIC-1 dose-dependently increased cell invasiveness, uPA activity, and uPA and uPAR expression. However, MIC-1 did not significantly suppress the proliferation of gastric cancer cell lines. We also found that the stimulation of human gastric cell lines with recombinant MIC-1 strongly induced activation of mitogen-activated protein kinase kinase-1/2 and extracellular signal-regulated kinase-1/2. Additional analysis revealed that PD98059, a selective inhibitor of mitogen-activated protein kinase kinase-1/2, suppressed not only gastric cancer cell invasiveness and uPA activity, but also the mRNA expressions of uPA and uPAR, as induced by recombinant MIC-1. Our results indicate that MIC-1 may contribute to the malignant progression of gastric cancer cells by inducing tumor cell invasion through the up-regulation of the uPA activation system via extracellular signal-regulated kinase-1/2-dependent pathway.     

Cyclooxygenase-2 uses the protein kinase C/ interleukin-8/urokinase-type plasminogen activator pathway to increase the invasiveness of breast cancer cells

Cyclooxygenase-2 (COX-2) increases breast cancer cell invasion. Expression of various pro-angiogenic and pro-invasive factors has been correlated with high expression of COX-2. However, whether these factors are essential to COX-2-mediated breast cancer invasion, and the mechanisms by which COX-2 increases the expression of these factors are unknown. Our microarray results indicate that higher COX-2 expression was associated with increased levels of interleukin-8 (IL-8), a key factor in breast cancer invasion and metastasis. COX-2 overexpressing cells (MCF-7/COX-2), generated by transfecting COX-2-encoding plasmids into the poorly invasive MCF-7 breast cancer cells, were more invasive and produced higher IL-8 levels than the parental cells. To investigate the role of IL-8 in COX-2-mediated invasion, MCF-7 parental cells were incubated with IL-8. Exogenous IL-8 increased the invasiveness of MCF-7 cells. IL-8 is one pathway by which COX-2 mediates breast cancer invasion. Protein kinase A (PKA) and protein kinase C (PKC) are activated by COX-2 and are involved in IL-8 regulation. Inhibition of PKC, not PKA, decreased IL-8 production and invasion in MCF-7/COX-2 cells. Activation of PKC, not PKA, increased IL-8 production and invasion in MCF-7 cells. Thus, the invasive effects of COX-2 are mediated by PKC, not PKA. Activity of the urokinase-type plasminogen activator (uPA) was increased in MCF-7 cells by COX-2 overexpression or by the addition of a PKC activator or by IL-8. Inhibition of PKC decreased uPA activity in MCF-7/COX-2 cells. Furthermore, inhibition of uPA activity decreased the invasiveness of MCF-7/COX-2 cells, indicating that uPA was essential to COX-2-mediated invasion. Herein we demonstrate for the first time a detailed mechanism by which COX-2 increases breast cancer invasion: the PKC/IL-8/uPA pathway.     

Positive regulation of migration and invasion by vasodilator-stimulated phosphoprotein via Rac1 pathway in human breast cancer cells

This study aimed to investigate the role of the cytoskeleton-associated protein vasodilator-stimulated phosphoprotein (VASP) on the migration and invasion of human breast cancer cells and its relationship to Rac1 which is a member of the Rho family and has been found to be implicated in tumorigenesis, invasion and metastasis. We detected the mRNA and protein expression levels of VASP and Rac1 of the non-invasive breast cancer cell line MCF-7 as well as the invasive cell line MDA-MB-231 by RT-PCR and Western blotting. GST pull-down assay was used to examine the activitiy of Rac1. Accordingly, the cell invasive migration ability was analyzed in a wound-healing assay (2D) and transwell assays (3D migration and invasion). We then used VASP-siRNA to inhibit the expression of VASP in breast cancer cells in order to study the relationship between the VASP expression level and the invasive migration ability of breast cancer cells. Rac1-siRNA was used to decrease the expression of Rac1, and observe its effect on the VASP expression level together with the migration and invasion ability of MCF-7 and MDA-MB-231 cells. Our results revealed that the invasive breast cancer cell line MDA-MB-231 showed a higher Rac1 activity and VASP expression level compared with the non-invasive MCF-7. Inhibition of Rac1 or VASP by siRNA, respectively, decreased the migration and invasion ability of breast cancer cells and the transfection of Rac1 siRNA-mediated reduction of VASP expression at mRNA and protein levels. Collectively, our data showed that the higher expression level of VASP contributed to a higher invasive migration capacity of human breast cancer cells which was controlled by the Rac1 pathway.     

Cell signaling by urokinase-type plasminogen activator receptor induces stem cell-like properties in breast cancer cells

Signaling by urokinase-type plasminogen activator receptor (uPAR) can cause epithelial-mesenchymal transition (EMT) in cultured breast cancer cells. In this report, we show that uPAR signaling can also induce cancer stem cell (CSC)-like properties. Ectopic overexpression of uPAR in human MDA-MB-468 breast cancer cells promoted the emergence of a CD24(-)/CD44(+) phenotype, characteristic of CSCs, while increasing the cell surface abundance of integrin subunits β1/CD29 and α6/CD49f that represent putative mammary gland stem cell biomarkers. uPAR overexpression increased mammosphere formation in vitro and tumor formation in an immunocompromized severe combined immunodeficient (SCID) mouse model of orthotopic breast cancer. Hypoxic conditions that are known to induce EMT in MDA-MB-468 cells also increased cell surface β1/CD29, mimicking the effects of uPAR overexpression. Antagonizing uPAR effector signaling pathways reversed the increase in cell surface integrin expression. Whereas uPAR overexpression did not induce EMT in MCF-7 breast cancer cells, CSC-like properties were nevertheless still induced along with an increase in tumor initiation and growth in the orthotopic setting in SCID mice. Notably, in MCF-7 cell mammospheres, which display a well-defined acinus-like structure with polarized expression of E-cadherin and β1-integrin, cell collapse into the central cavity was decreased by uPAR overexpression, suggesting that uPAR signaling may stabilize epithelial morphology. In summary, our findings show that uPAR signaling can induce CSC-like properties in breast cancer cells, either concomitantly with or separately from EMT.     

Inhibition of tumor growth and metastasis by ATF-Fc, an engineered antibody targeting urokinase receptor

Urokinase (uPA) and its receptor (uPAR) play an important role in tumor growth and metastasis, and overexpression of these molecules is strongly correlated with poor prognosis in a variety of malignant tumors. In this study, ATF-Fc, an antibody-like molecule comprising the amino-terminal fragment of human uPA (ATF) linked to the Fc fragment of human IgG1 via a flexible linker was developed. Its antitumor activities were evaluated in vitro and in vivo. The results showed that ATF-Fc had obvious cytotoxic effect on several types of tumor cells, which is dependent on cellular expression of uPAR and its Fc fragment. Treatment with ATF-Fc caused a significant suppression on tumor growth and metastasis of xenograft human tumors (MCF-7 breast cancer and BGC-823 gastric cancer) in athymic nude mice. Furthermore, we demonstrated that ATF-Fc had an anti-angiogenesis activity both in vitro and in vivo. In conclusion, we provided a novel therapeutic antibody-like molecule in the management of a variety of solid tumors by disrupting the uPA/uPAR interaction.     

CD44 stimulation by fragmented hyaluronic acid induces upregulation of urokinase-type plasminogen activator and its receptor and subsequently facilitates invasion of human chondrosarcoma cells

It has been established that fragmented hyaluronic acid (HA), but not native high molecular weight HA, can induce angiogenesis, cell proliferation and migration. We have studied the outside-in signal transduction pathways responsible for fragmented HA-mediated cancer cell invasion. In our study, we have studied the effects of CD44 stimulation by ligation with HA upon the expression of matrix metalloproteinases (MMPs)-2 and -9 as well as urokinase-type plasminogen activator (uPA), its receptor (uPAR) and its inhibitor (PAI-1) and the subsequent induction of invasion of human chondrosarcoma cell line HCS-2/8. Our study indicates that (i) CD44 stimulation by fragmented HA upregulates expression of uPA and uPAR mRNA and protein but does not affect MMPs secretion or PAI-1 mRNA expression; (ii) the effects of HA fragments are critically HA size dependent: high molecular weight HA is inactive, but lower molecular weight fragmented HA (Mr 3.5 kDa) is active; (iii) cells can bind avidly Mr 3.5 kDa fragmented HA through a CD44 molecule, whereas cells do not effectively bind higher Mr HA; (iv) a fragmented HA induces phosphorylation of MAP kinase proteins (MEK1/2, ERK1/2 and c-Jun) within 30 min; (v) CD44 is critical for the response (activation of MAP kinase and upregulation of uPA and uPAR expression); and (vi) cell invasion induced by CD44 stimulation with a fragmented HA is inhibited by anti-CD44 mAb, MAP kinase inhibitors, neutralizing anti-uPAR pAb, anti-catalytic anti-uPA mAb or amiloride. Therefore, our study represents the first report that CD44 stimulation induced by a fragmented HA results in activation of MAP kinase and, subsequently, enhances uPA and uPAR expression and facilitates invasion of human chondrosarcoma cells.     

Maspin regulates hypoxia-mediated stimulation of uPA/uPAR complex in invasive breast cancer cells

Maspin, a unique serine proteinase inhibitor (serpin), plays a key role in mammary gland development and is silenced during breast cancer progression. Maspin has been shown to inhibit tumor cell motility and invasion in cell culture, as well as growth and metastasis in animal models. In this study, we investigated the effect of maspin on the regulation of hypoxia-induced expression of urokinase-type plasminogen activator (uPA) and its receptor (uPAR), with respect to invasive potential in metastatic breast cells MDA-MB-231. We hypothesized that maspin can neutralize or mitigate hypoxia-induced expression of uPA/uPAR in metastatic breast cancer cells, resulting in suppression of their invasive potential. To test our hypothesis, we employed the highly invasive MDA-MB-231 breast cancer cells that are devoid of maspin, and transfected them with the maspin gene, and then determined the effect of hypoxia on uPA/uPAR expression. Normal mammary epithelial cells 1436N1 were used as a control. Our findings demonstrate that maspin downregulated the basal and hypoxia-induced uPA/uPAR expression and reduced the stimulatory effect of hypoxia on the in vitro invasive ability of MDA-MB-231-cells. In addition, maspin also inhibited the enzymatic activity of secreted and cell associated uPA in MDA-MB-231 cells. These results indicate that maspin inhibits hypoxia-induced invasion of metastatic breast cancer cells by blocking the uPA system, thus illuminating an important molecular pathway for therapeutic consideration.     

p38MAPK信号通路与uPA在乳腺癌细胞及组织中表达的相关性

背景与目的:p38MAPK信号通路介导多种转移相关基因表达调控,尿激酶型纤溶酶原激活剂(urokinase-type plasminogen activator,uPA)在肿瘤浸润和转移中发挥着重要作用.本实验研究人乳腺癌组织中3种信号分子p-p38、p-Akt、p-Erk及uPA表达与临床病理特征的关系,并分析它们与uPA表达的相关性,探讨p38MAPK通路对乳腺癌uPA蛋白表达的影响,分析p-p38和uPA表达与乳腺癌预后的关系.方法:应用免疫组织化学(SP)法检测p-p38、p-Akt、p-Erk和uPA在60例乳腺癌组织中的表达.Western blot检测人乳腺癌细胞MDA-MB-231及MCF-7中p-p38及uPA蛋白表达及用p38MAPK特异性抑制剂SB203580阻断p38MAPK信号通路后uPA蛋白表达水平的变化.结果:p-p38、p-Akt、p-Erk、uPA蛋白在乳腺癌组织中表达阳性率分别为56.7%、95.0%、93.3%、60.0%.p-p38与uPA表达存在正相关(r=0.316,P＜0.05),并与乳腺癌的TNM分期及淋巴结转移状况相关(P＜0.05),而与患者年龄、肿瘤大小无明显相关性(P＞0.05).p-Akt、p-Erk与uPA表达无明显相关性,p-Akt和p-Erk蛋白表达与乳腺癌的淋巴结转移有关(P＜0.05)而与患者年龄、肿瘤大小、TNM分期均无明显关系(P＞0.05).乳腺癌细胞MDA-MB-231中p-p38及uPA蛋白表达水平高于MCF-7.用SB203580阻断p38MAPK通路可降低uPA蛋白表达水平,且随着SB203580浓度升高uPA表达水平逐渐降低.乳腺癌中p-p38和uPA蛋白的表达与肿瘤的预后显著相关(分别为log-rank=4.98、5.40,P=0.0256、0.0201).结论:p38MAPK信号通路可能通过上调uPA的表达促进乳腺癌的恶性进展,p38MAPK信号通路可能是乳腺癌侵袭和转移的重要途径,p-p38和uPA的表达可辅助用于乳腺癌的预后评估.     

Urokinase plasminogen activator system gene expression is increased in human breast carcinoma and its bone metastases — A comparison of normal breast tissue, non-invasive and invasive carcinoma and osseous metastases

The urokinase plasminogen activator (uPA) system has been widely associated with the development of breast carcinoma. However, the role of the urokinase pathway in the development of osseous breast cancer metastases has been largely overlooked. We studied the expression of uPA, urokinase plasminogen activator receptor (uPAR) and plasminogen activator inhibitor type-1 (PAI-1) in human breast carcinomas and their bone metastases, using in situ hybridisation. Studies were performed using paraffin-embedded tissue from 13 ductal carcinomas, 23 invasive ductal carcinomas, five normal breasts and 25 bone metastases. The majority of the tumours examined expressed low to moderate levels of uPA mRNA and low to high levels of uPAR and PAI-1 mRNA, which was predominantly localised to the epithelial tumour cells. There was slight over-expression of uPA and PAI-1 mRNA and a marked increase in uPAR mRNA expression in the malignant tumours compared with benign tissue. Overall, uPAR and PAI-1 mRNA expression was found to be more variable than uPA mRNA, suggesting a possible role of the receptor and inhibitor in the regulation of uPA activity. Increased 1(I) procollagen (COL) and osteopontin (OPN) mRNA expression was detected, primarily in the stromal cells, in malignant tumours compared with the benign tissue. The increased expression of the components of the uPA system on the epithelial tumour cells may account for the activation of the proteolytic cascade that occurs during breast cancer metastasis to bone. Furthermore, the over-expression of COL and OPN suggests a possible interaction between these matrix proteins and the uPA system.     

Stromal cells associated with early invasive foci in human mammary ductal carcinoma in situ coexpress urokinase and urokinase receptor

The transition from ductal carcinoma in situ (DCIS) of the breast to invasive ductal carcinoma is facilitated by proteolytic degradation of basement membrane. The transition can be identified as microinvasive foci in a small proportion of DCIS lesions. We have previously found that MMP-13 is frequently expressed in such foci. To establish whether plasmin-directed proteolysis is likely to be involved in early invasion, we have here studied the expression of urokinase plasminogen activator (uPA) and its receptor (uPAR) in human DCIS lesions with and without microinvasion. uPA mRNA was detected in periductal stromal cells in all of 9 DCIS lesions with microinvasion and in 2 of 9 DCIS lesions without microinvasion by in situ hybridization. The uPA mRNA signal was seen in numerous stromal cells in microinvasive areas together with MMP-13 mRNA expressing cells. Double immunofluorescence analyses, using emission fingerprinting, showed that the uPA expressing stromal cells included both myofibroblasts and macrophages. The early invasive carcinoma cells were negative for uPA. uPAR immunoreactivity was focally upregulated in periductal stromal cells in all of the 9 DCIS lesions with microinvasion and in only 2 of the 9 DCIS lesions without microinvasion. uPAR was seen in both macrophages and myofibroblasts in microinvasive areas, and it was evident that uPA and uPAR colocalized in both fibroblast-like cells and macrophage-like cells. We conclude that periductal macrophages and myofibroblasts are strongly involved in the initial steps of breast cancer invasion by focally upregulating the expression of the plasminogen activation system and MMP-13.     

Calcitonin inhibits invasion of breast cancer cells: involvement of urokinase-type plasminogen activator (uPA) and uPA receptor

There is a growing body of evidence indicating that calcitonin (CT) and calcitonin receptor (CTR) are involved in the regulation of cell growth, differentiation, and survival and in tissue development. However, the precise functional role of CT/CTR in breast cancer is still unknown. It is well established that the urokinase plasminogen activator (uPA) system plays an important role in breast cancer invasion and metastasis. The goal of this study was to investigate the effects of CT on regulation of the uPA system and invasive capacity of breast cancer cells. In the highly invasive MDA-MB-231 cell line, 10(-8) M CT decreased both uPA and uPAR mRNA and protein expression which was associated with inhibition of the extracellular signal-regulated kinase (ERK) 1/2 pathway. Furthermore, two weeks of CT administration to nude mice inhibited the expression of uPA mRNA in primary tumors by 25% (P<0.05), as compared to control, untreated animals. CT also inhibited the invasiveness of MDA-MB-231 cells by 37% (10(-8) M CT, P<0.05), as determined by a Matrigel invasion assay. To the best of our knowledge, this is the first report describing a direct effect of CT on breast cancer cell invasion. Our data might suggest a close link between CT signaling, the uPA-mediated pathway, and breast cancer invasion.     

Galectin-3 在人乳腺癌组织中的表达及对MCF-7 细胞恶性生物学行为的影响

目的：探讨半乳凝集素-3（galectin-3）蛋白在人乳腺癌组织中的表达规律及沉默galectin-3 基因后对乳腺癌MCF-7 细胞迁移、侵袭和凋亡的影响。方法：收集2014 年2 月至2018 年2 月邢台市人民医院手术切除的15 例乳腺癌患者癌组织及其癌旁组织,另外采集该医院和河北医科大学附属第四医院组织石蜡切片100 份,利用Western blotting 检测15 例乳腺癌患者的癌组织及癌旁组织中galectin-3 蛋白相对表达水平,用免疫组织化学法检测galectin-3 蛋白在100 例乳腺癌石蜡标本切片中的表达水平,并分析其表达与患者临床病理特征的关系。将galectin-3 siRNA 转染至MCF-7 细胞中,用qPCR 法和Western blotting 分别检测galectin-3 mRNA和蛋白的表达水平;用Transwell 小室法和流式细胞术分别检测galectin-3 基因沉默后对MCF-7 细胞迁移、侵袭和凋亡的影响。结果：在乳腺癌组织中galectin-3 蛋白表达水平显著高于癌旁组织（P<0.05）;乳腺癌组织中galectin-3 蛋白阳性表达率为67.00%,其表达水平在淋巴结转移、激素受体（ER、PR）阴性组中显著升高（均P<0.05）,且随TNM分期和组织学分级的升高而升高（均P<0.05）。转染galectin-3 siRNA 后,能显著降低MCF-7 细胞galectin-3 mRNA和蛋白的表达水平、迁移和侵袭能力（均P<0.05）,提高细胞的凋亡率（P<0.05）。结论：Galectin-3 在乳腺癌组织中高表达,沉默galectin-3 表达后抑制MCF-7 细胞的迁移和侵袭、诱导细胞凋亡,可作为乳腺癌生物治疗的一个新靶点。     

Urokinase type plasminogen activator and its receptor regulate the invasive potential of gastric cancer cell lines

To assess the role of urokinase-type plasminogen activator (uPA) and uPA receptor (uPAR) on the invasive potential of cancer cells, in vitro experiments were performed using two human gastric cancer cell lines, NUGC-3 and MKN-28. NUGC-3 cells secreted a higher level of uPA than MKN-28 cells, while the uPAR expression of NUGC-3 cells was lower than that of MKN-28 cells. Both cancer cell lines expressed Met protein and did not express hepatocyte growth factor (HGF). In Matrigel invasion assay, MKN-28 cells demonstrated significantly lower invasion index than NUGC-3 cells. The addition of exogenous uPA significantly increased the invasive activity of MKN-28 cells. The uPA expression in NUGC-3 cells was enhanced by adding conditioned media of fibroblast cells or HGF. These results suggest that uPA promotes the invasive capacity of the uPAR-positive cancer cells, and that stromal cells may play an important role in cancer cell invasion by supplying uPA and/or promoting uPA production.     

二甲基阿米洛利对高转移性肺癌细胞侵袭能力的影响及其作用机制

目的:研究二甲基阿米洛利(dimethyl amiloride, DMA)对人高转移性肺癌PGCL3细胞体外侵袭能力的影响,并探讨其可能的作用机制.方法:肺癌PGCL3细胞经DMA处理后,用Transwell小室法检测其对细胞侵袭和运动能力的影响,发色底物法检测DMA对细胞分泌的尿激酶型纤溶酶原激活物(urokinase-type plasminogen activator, uPA)和纤溶酶原激活物抑制剂1(plasminogen activator inhibitor-1, PAI-1)活性的影响,RT-PCR检测DMA对细胞uPA、尿激酶型纤溶酶原激活物受体(urokinase-type plasminogen activator receptor, uPAR)和PAI-1 mRNA表达的影响,Western印迹法检测细胞外调节蛋白激酶2(extracellular regulated protein kinases 2,ERK2)和ras蛋白表达的变化.结果:DMA能抑制PGCL3细胞的体外侵袭和运动能力,下调uPA、uPAR和PAI-1的mRNA表达,上调ras蛋白的表达;高浓度时DMA可降低细胞分泌的uPA活性,但对分泌型PAI-1活性和ERK2蛋白表达无影响.结论:DMA能抑制高转移性肺癌PGCL3细胞的侵袭和运动,其作用机制可能与抑制uPA系统的表达有关.