4-[3,5-Bis(trimethylsilyl)benzamido] benzoic acid (TAC-101) inhibits the intrahepatic spread of hepatocellular carcinoma and prolongs the life-span of tumor-bearing animals

We examined the in vivo anti-tumor activity of the benzoic acid derivative, TAC-101 (4-[3,5- bis(trimethylsilyl)benzamido] benzoic acid), for intrahepatic spread of JHH-7 human hepatocellular carci-noma (HCC) cells and its mechanism of action. Oral administration of TAC-101 markedly inhibited liver tumor of JHH-7 cells and prolonged the life-span of tumor-bearing mice without affecting the body weight. The life-prolonging effect of TAC-101 was more effective than that of other anti-cancer agents including CDDP, 5-FU, and CPT-11 (T/C (%) of life-span ; 181 to 219, 128, 133, and 142%, respectively). In vitro, TAC-101 at the concentration of more than 10 mM showed direct cytotoxicity against JHH-7 cells caused by induction of apoptosis. Hepatocyte growth factor (HGF) enhanced the invasive ability of JHH-7 cells without affecting the cell viability. Non-cytotoxic concentrations of TAC-101 inhibited the JHH-7 invasion induced by HGF and down-regulated the expression of c-MET protein in a concentration-dependent manner. In summary, these results suggest that TAC-101 would be useful for a new class of therapeutic agents and that it may improve the prognosis of patients with liver-tumors including metastasizing tumor and HCC. ©Lippincott Williams & Wilkins     

Establishment and characterization of three novel human gastric cancer cell lines with differentiated intestinal phenotype derived from liver metastasis

Gastric cancers with liver metastasis are fatal diseases with rapid progression and poor patient outcome. To date, however, the molecular basis of their growth and metastasis remains essentially unknown, largely because of the presence of few available gastric cancer cell lines established from liver metastasis. In the present study, we developed two novel cultured cell lines (designated GLM-1 and GLM-2) and one transplantable line in nude mice (designated GLM-3) derived from liver metastasis of gastric cancer patients. These GLM cell lines share unique biological features such as differentiation, growth and metastasis. They form moderately differentiated tumors with CD10 positive and MUC2 negative intestinal absorptive phenotype when injected into nude mice. Their growth is stimulated by EGF and TGF-α in vitro like other gastric cancer cell lines. However, GLM cells differ from conventional gastric cancer cell lines in their high apoptotic rate, even in the absence of apoptosis inducing stimuli as revealed by Caspase3/7 assay and the TUNEL method. This apoptosis is further enhanced by phosphatidylinositol 3-kinase (PI3K) inhibitor (LY294002), but not by MEK1/2 inhibitor (U0126), indicating the strong dependency of their survival on PI3K/Akt pathway rather than MAPK pathway, the major downstream signaling pathways of EGFR. GLM-1 cells can metastasize to the liver after intrasplenic injection, and GLM-3 cells have spontaneous lung metastatic potential after subcutaneous transplantation, respectively. These results indicate that the GLM series are the first cell lines reflecting the intestinal-type differentiated adenocarcinoma, a major subtype of gastric cancer with liver metastasis. Therefore, they would be excellent models for understanding the mechanism of metastatic growth and the development of a new molecular targeting therapy for gastric cancer with liver metastasis.     

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.     

Different effects of constitutive nitric oxide synthase and heme oxygenase on pulmonary or liver metastasis of colon cancer in mice

It has recently been reported that not only endogenous nitric oxide (NO) but also carbon monoxide (CO) produced by heme oxygenase (HO) have many physiological functions. The objective of the present study was to determine whether endogenous NO or CO is involved in the experimental pulmonary or liver metastasis of colon cancer in mice. Intravenous or intrasplenic injection of colon 26 cells from a mouse colon adenocarcinoma cell line resulted in multiple pulmonary or liver metastases. NG-nitro-l-arginine methyl ester (l-NAME), a competitive inhibitor of NO synthase (NOS), or zinc deuteroporphyrin 2, 4-bis glycol (ZnDPBG), a competitive inhibitor of HO, was administered to the mice only on the day of tumor inoculation. We assessed the number of tumor cells 24 h later and the outcome of metastases of the target organ. In the pulmonary metastasis model, l-NAME increased both the number of tumor cells 24 h later and outcome of metastases 18 days later, but did not have a significant effect on liver metastasis. On the other hand, metastasis to the liver, but not that to the lung, increased following administration of ZnDPBG. These results suggest that the activities of NOS and HO could influence experimental metastasis in an organ-specific manner. This revised version was published online in July 2006 with corrections to the Cover Date.     

Carcinoembryonic antigen promotes tumor cell survival in liver through an IL-10-dependent pathway

Most circulating tumor cells die within 24 h of entering the hepatic microvasculature because their arrest initiates an ischemia-reperfusion (I/R) injury that is cytotoxic. Human colorectal carcinomas (CRC) produce the glycoprotein Carcinoembryonic Antigen (CEA) that increases experimental liver metastasis in nude mice. Since CEA induces release of IL-6 and IL-10, we hypothesized that CEA inhibits the I/R injury through a Kupffer cell-mediated cytokine-dependent pathway. We assessed cytokine effects in CRC co-cultured with liver and in vivo. Human CRC prelabeled with fluorescent dyes were incubated with a reoxygenated suspension of ischemic nude mouse liver fragments in a bioreactor. CEA, rhIL-6 or rhIL-10 were either administered to the donor mice prior to hepatic ischemia or during co-culture. Liver donors were athymic nude or iNOS, IL-6 or IL-10 knock out mice. Ischemic-reoxygenated liver kills Clone A CRC through production of nitric oxide (NO) and superoxide anion. Treatment of liver donors with CEA prior to hepatic ischemia inhibited this in vitro cytotoxicity through an IL-10 and Kupffer cell dependent pathway that inhibited NF-κB activation, NO production and iNOS upregulation. IL-10 but not IL-6 enhanced CRC survival in nude mouse liver in vivo. Thus, CEA enhanced metastasis by inducing IL-10 to inhibit iNOS upregulation in host liver.This revised version was published online in August 2005 with a corrected cover date.     

Antitumor effect of natural human tumor necrosis factor-alpha and natural human interferon-alpha in combination against human cancer transplanted into nude mice

We studied the in vivo antitumor effects of natural human tumor necrosis factor-alpha (nHuTNF-alpha) and natural human interferon-alpha (nHuIFN-alpha), both of which were produced by HVJ (hemagglutinating virus of Japan)-stimulated acute lymphatic B cell leukemia line, BALL-1 cells. To clarify the interaction between nHuTNF-alpha and nHuIFN-alpha, we used novel experimental models of lung metastasis and intraabdominal carcinomatosis which we developed in nude mice using a human tumor line, RPMI 4788. While the intravenous administration of nHuTNF-alpha or nHuIFN-alpha alone inhibited lung metastasis, the two cytokines given in combination synergistically inhibited lung metastasis. In a comparative study, nHuTNF-alpha and recombinant human interferon-gamma (rHuIFN-gamma) in combination also synergistically inhibited lung metastasis. Treatment with nHuTNF-alpha and nHuIFN-alpha combined significantly prolonged the survival of nude mice with intraabdominal carcinomatosis. Complete regression of five different human tumor xenografts was achieved by the simultaneous intratumoral injection of nHuTNF-alpha and nHuIFN-alpha. Histological examination revealed that tumor cell lysis occurred 24 h after the intratumoral administration of the cytokines. No significant signs of toxicity to nude mice were observed at any dose tested. The synergism of nHuTNF-alpha and nHuIFN-alpha may allow treatment at a relatively low dose range, thus minimizing side effects. The wide range of anticancer activity of these agents may provide better therapeutic efficacy. The in vivo assay systems which we have developed are useful for the analysis of the biological activities and interactions of cytokines and chemotherapeutic drugs.     

Growth and metastatic behavior of human tumor cells implanted into nude and beige nude mice

The growth and metastatic behavior of several human tumor lines grown in adult nude mice, nude mice pretreated with antiserum against asialo GM1 glycoprotein, and beige nude mice were studied. The cell lines were all injected s.c. and i.v. A human colon carcinoma line was also injected into the spleen, and two human renal carcinoma lines were injected into renal subcapsule. All the tumor lines grew as fast or faster in adult nude mice compared with beige nude mice. There were no discernible differences in the production of experimental lung metastasis among the three groups of mice, but human colorectal carcinoma cells and human renal carcinoma cells produced more metastases in nude mice than in beige nude mice after intrasplenic or renal subcapsule injection, respectively. In vitro cytotoxicity assays confirmed that adult nude mice had high levels of natural killer (NK) cell activity whereas nude mice pretreated with anti-asialo GM1 serum and beige nude mice did not. The in vitro NK cell activity of nude mice was demonstrable against mouse lymphoma cells but not against human leukemia cells which were sensitive to lysis by human NK cells. These results suggest that the implantation of human tumor cells into beige nude mice, which are deficient in NK cell activity does not provide an advantageous model for the study of growth and metastasis of human neoplasms.Abbreviations NK natural killer - HCC human colon carcinoma - HRCC human renal cell carcinoma - anti-asGM1 anti-asialo GM1 - i.s. intrasplenic - RSC renal subcapsule - HBSS Ca²⁺- and Mg²⁺-free Hanks' balanced salt solution     

The spread of human lung cancer cells on collagens and its inhibition by type III collagen

The cell spreading ability of human lung cancer cells on collagen substrata was examined in comparison with normal human tracheal epithelial cells. Plastic dishes or multiwells were coated with type I, III or IV collagen gel at a concentrate of 200 g/cm². Ninety per cent of the normal cells were round on all collagens. Adenocarcinoma RERF-LC-MS and VMRC-LCD cell lines and squamous cell carcinoma VMRC-LCP cell line, which metastasize weakly after intrasplenic transplantation in nude mice, spread relatively poorly. Adenocarcinoma, A549 and SK-LU-1 and squamous cell carcinoma Calu-1 cell lines, which were highly metastatic to liver, spread well. Adenocarcinoma ABC-1 cell line, which is moderately metastatic to liver in nude mice, spread moderately. On type III collagen, three adenocarcinoma cell lines (A549, ABC-1 and VMRC-LCD) gradually started to contract after initial spreading and became round at 24 h. These results suggest that there may be a correlation between the degree of malignancy of human lung cancer cells and their spreading ability on collagen substrata, and that the cell spreading ability may be regulated by type III collagen in some lung cancer cells.     

Carcinoembryonic antigen promotes tumor cell survival in liver through an IL-10-dependent pathway

Most circulating tumor cells die within 24 h of entering the hepatic microvasculature because their arrest initiates an ischemia-reperfusion (I/R) injury that is cytotoxic. Human colorectal carcinomas (CRC) produce the glycoprotein Carcinoembryonic Antigen (CEA) that increases experimental liver metastasis in nude mice. Since CEA induces release of IL-6 and IL-10, we hypothesized that CEA inhibits the I/R injury through a Kupffer cell-mediated cytokine-dependent pathway. We assessed cytokine effects in CRC co-cultured with liver and in vivo. Human CRC prelabeled with fluorescent dyes were incubated with a reoxygenated suspension of ischemic nude mouse liver fragments in a bioreactor. CEA, rhIL-6 or rhIL-10 were either administered to the donor mice prior to hepatic ischemia or during co-culture. Liver donors were athymic nude or iNOS, IL-6 or IL-10 knock out mice. Ischemic-reoxygenated liver kills Clone A CRC through production of nitric oxide (NO) and superoxide anion. Treatment of liver donors with CEA prior to hepatic ischemia inhibited this in vitro cytotoxicity through an IL-10 and Kupffer cell dependent pathway that inhibited NF-kappaB activation, NO production and iNOS upregulation. IL-10 but not IL-6 enhanced CRC survival in nude mouse liver in vivo. Thus, CEA enhanced metastasis by inducing IL-10 to inhibit iNOS upregulation in host liver.     

Metastatic potential of human colon cancer cell lines: relationship to cellular differentiation and carcinoembryonic antigen production

The relationship between cellular differentiation and carcinoembryonic antigen (CEA) production by human colorectal tumor cells and their ability to form hepatic metastases was studied. Eight human colon cancer cell lines were injected into athymic mice using different routes of administration to characterize their metastatic potential. The four poorly differentiated, non or low CEA producing cell lines were poorly metastatic to the liver after intrasplenic injection. After intraperitoneal implantation the same cell lines were highly tumorigenic, and subsequently metastastic to the liver. In contrast, the four moderate to well-differentiated cell lines that produced moderate to high levels of CEA were highly metastatic to the liver following intrasplenic injection. After intraperitoneal implantation they were less tumorigenic, and metastatic to the liver. We conclude that in this system poorly differentiated non or low CEA producing colorectal cell lines have a lower metastatic capacity compared to the well-differentiated high CEA producing colorectal cell lines. These data correlate directly with the pattern of metastatic spread and clinical course observed in patients with these tumors, suggesting that degree of differentiation and level of CEA production may play a role in development of site-specific metastases.     

高表达活化白细胞黏附因子对AZ-521胃癌细胞系增殖能力的影响

目的:探讨活化白细胞黏附分子(Activated leukocyte cell adhesion molecule,ALCAM),即CD166对AZ-521胃癌细胞系增殖能力的影响。方法:以pLOX-CWBmi1-CD166慢病毒质粒感染胃癌细胞株AZ-521,采用荧光定量PCR以及Western blot分别测定CD166 mRNA和蛋白表达情况;采用CCK-8测定细胞增殖情况;采用吉姆萨染色测定细胞克隆形成数。结果:pLOX-CWBmi1-CD166慢病毒质粒感染胃癌细胞株AZ-521后CD166 mRNA和蛋白水平均明显增加(P<0.05);细胞增殖能力明显增加(P<0.05);细胞克隆形成数量明显增多(P<0.05)。体内成瘤实验显示,CD166过表达小鼠肿瘤体积明显大于对照细胞(P<0.05)。结论:CD166可促进AZ-521胃癌细胞系增殖。     

肝癌发生与转移过程中E—选择素在裸鼠肝、肺、肾微血管内皮细胞的表达

目的：观察肝原位种植肝癌裸鼠模型在肿瘤发生与转移过程中E－选择素在肝、肺、肾组织中的表达。方法：将人肝癌组织块直接种植于裸鼠肝内,术后15、17、19、21、40天取材,免疫组化法观察。结果：肝癌种植后第15－17天,肝、肺、肾组织中微血管内皮细胞E－选择素呈弱阳性表达,种植后第19天,肝血窦内皮细胞呈强阳性表达。种植后第19天,肺组织内E－t选择素表达增强。至40天时,表达最强,结论：E－选择素的表达和增强与肝癌的发生和转移有关。     

A novel bisphosphonate minodronate (YM529) specifically inhibits osteolytic bone metastasis produced by human small-cell lung cancer cells in NK-cell depleted SCID mice

In the present study, we examined the effects of a newly developed bisphosphonate, minodronate (YM529), on osteolytic bone metastasis caused by lung cancer. Human small-cell lung cancer (SBC-5) cells, injected intravenously into natural killer cell-depleted SCID mice, produced radiologically detectable bone metastasis by day 18 and macroscopically visible visceral metastases (lung, liver, kidney, systemic lymph node) by day 35. Prophylactic treatment with YM529 on day 1 significantly inhibited the formation of osteolytic bone metastasis evaluated on X-ray photographs in a dose-dependent manner. In addition, treatment with YM529 after establishment of bone metastasis (on day 21) also inhibited bone metastasis, although the treatment was more effective when started earlier. Single administration was as effective as repeated treatment, suggesting a sustained inhibitory effect of YM529 on bone metastasis. YM529 reduced the number of osteoclasts in the bone metastatic lesions in vivo, but had no effect on the proliferation or cytokine production of SBC-5 cells in vitro. These results suggest that YM529 is a potent inhibitor of bone metastasis of human lung cancer, probably by suppressing osteoclastic bone resorption. In contrast, treatment with YM529 had no effect on visceral metastasis, even if started on day 1, and did not prolong the survival of the mice. Therefore, development of a combined modality is necessary for prolonging the survival of small-cell lung cancer patients with multiple-organ metastasis. This revised version was published online in July 2006 with corrections to the Cover Date.     

小鼠肝B220~+/DEC205~+树突状细胞对结肠癌肝转移的影响

目的:研究小鼠肝内B220~+/DEC205~+树突状细胞对结肠癌肝转移的影响.方法:小鼠尾静脉大容量快速注射重组质粒plasmid-IL-3/CD40L,诱导肝B220~+/DEC205~+树突状细胞增殖,小鼠脾内接种结肠腺癌CT26细胞,检测肝表面转移癌结节数量及脾内癌结节大小和重量、血清癌胚抗原含量及小鼠生存期.结果:处理组小鼠肝非实质细胞较对照组明显增多.小鼠脾包膜下接种CT26细胞后第14天,脾均有癌结节形成,仅肝表面见癌转移结节,转移率为100%.处理组肝表面转移癌结节数量明显多于对照组.脾内癌结节的大小、重量,处理组与对照组比较无明显差别.处理组较对照组血清癌胚抗原水平显著升高,小鼠生存期较对照组缩短.结论:小鼠肝内经重组质粒plasmid-IL-3/CD40L诱导扩增的B220~+/DCE205~+树突状细胞对结肠癌肝转移具有促进作用.     

Carcinoembryonic antigen facilitates experimental metastasis through a mechanism that does not involve adhesion to liver cells

Carcinoembryonic antigen (CEA) injected intravenously into athymic nude mice increases the ability of weakly metastatic human colorectal carcinoma (CRC) cells to colonize liver in an experimental metastasis assay. Since CEA acts as an intercellular adhesion molecule in vitro, several investigators have postulated that this facilitation of experimental metastasis may be mediated through adhesion between CEA on CRC and CEA-binding proteins on Kupffer or other cells lining the hepatic sinusoid. The present work tested this postulate both by intravital fluorescence videomicroscopy in vivo and in adhesion assays in vitro to enriched populations of Kupffer cells and hepatic sinusoidal endothelial cells (SEC). The data indicate that CEA expression does not effect adhesion to enriched Kupffer cells or SEC in vitro. These data suggest that CEA enhances liver colonization through another mechanism, possibly one that involves modulation of the hepatic response to tumor cell implantation. This revised version was published online in July 2006 with corrections to the Cover Date.     

Selection of more aggressive variants of the GI101A human breast cancer cell line: A model for analyzing the metastatic phenotype of breast cancer

In vivo models utilizing orthotopic injection of tumor cells into nude mice have proven valuable for the study of metastasis. However, breast cancers are among the more difficult of human tumors to grow in immunodeficient mice, with a relatively low tumor take. Fewer still develop spontaneous metastases. The injection of GI101A breast cancer cells into the mammary fatpad (mfp) produced lung metastases in 25% of tumor-bearing mice. Selecting cells from the lung metastases and recycling in vivo resulted in the isolation of a series of variant cell lines. These cell lines were tested for tumorigenicity and metastasis in nude mice following mfp injection compared with the original cell line, and in vitro expression of factors associated with the metastatic phenotype measured. The in vivo selected cell lines were more aggressive, with higher tumor take, faster local growth rate and increased incidence (≥85%) and extent of lung metastasis. However, the metastasis-selected variants showed no increases in expression of the growth factor receptors EGFR or HER-2, and the pro-angiogenic factors VEGF-A and IL-8. Immunohistochemistry of mfp tumors revealed no differences in microvessel density (counting CD-31 positive structures) and cell proliferation (PCNA-positive cells) comparing the GI101A line with selected variants. No TUNEL-positive cells were detected in the tumors of the metastasis-derived variant, with a small number of cells undergoing apoptosis detected in sections of GI101A tumors. In vitro, the metastasis-derived variants were found to have a more robust expression of phosphorylated PKB/Akt, with or without EGF or serum stimulation, suggesting an association between Akt activation and metastatic ability. This new series of isogenic cell lines may be valuable for identifying molecular mechanisms involved in the metastatic progression of breast cancer. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effects of suramin on metastatic ability,proliferation, and production of urokinase-type plasminogen activator and plasminogen activator inhibitor type 2 in human renal cell carcinoma cell line SN12C-PM6

Effects of suramin, a polysulfonated naphthylurea compound, on metastatic ability, proliferation, and production of plasminogen activators and plasminogen activator inhibitors were studied using the highly metastatic human renal cell carcinoma cell line, SN12C-PM6. After renal subscapular implantation of tumor cells in nude mice, suramin significantly inhibited metastasis of tumor cells to the lungs and liver. In vitro growth of tumour cells was inhibited by suramin in a dose-dependent manner, at relatively low doses (ID₅₀ = 105 µg/ml). Plasminogen activator inhibitor type 2 (PAI-2) production by tumor cells was enhanced by suramin (100 µg/ml), whereas urokinase-type plasminogen activator (uPA) production was suppressed. Thus, the increase in PAI-2 and the decrease in uPA production correlated with the inhibitory effects on tumour growth and metastasis by suramin. Therefore suramin may be beneficial for the treatment of patients with an early stage of renal cancer with potential risk of metastasis.     

Expression profiling and interferon-beta regulation of liver metastases in colorectal cancer cells

Liver metastasis is the major cause of death among colorectal cancer patients. Many gene products have been associated with the colon cancer cells' ability to metastasize to the liver, including carcinoembryonic antigen (CEA) and mucins. In this study we examined changes in expression of 384 genes in a model of human colorectal cancer metastasis in nude mice. Using DNA microarrays, we compared expression between MIP-101 cells, a poorly metastatic human colon cancer cell line, with an interferon-beta (IFN-β) resistant subline of MIP-101 (β-MIP) that is metastatic to the liver. Treatment of β-MIP cells with increasing concentrations of IFN-β caused a reversion to the non-metastatic phenotype. The array data showed down-regulation of genes involved in apoptosis in β-MIP cells and their return to the MIP-101 pattern upon IFN-β treatment. Cluster analysis also showed involvement of genes belonging to cell cycle, angiogenesis and invasion pathways. Selected genes were chosen to validate the microarray data by semi-quantitative RT-PCR. Association between gene expression pattern and metastatic phenotype was verified by intra-splenic injection in nude mice. The number of genes examined in this study was small, but carefully selected. Significant changes associated with cell growth and survival were observed, which gave the metastatic cells an advantage to grow in the liver. This information may help identifying new markers for colorectal cancer prognosis as well as aid the development of new therapeutic approaches. This revised version was published online in July 2006 with corrections to the Cover Date.     

血管内皮生长因子反义基因转染对高转移人巨细胞肺癌细胞系生 …

目的 探讨反义血管内皮生长因子（ＶＥＧＦ）基因转染在抑制恶性肿瘤生长和转移的抗肿瘤血管基因治疗中的意义。方法 利用基因重组技术构建正义和反义ＶＥＧＦ１２１ ｃＤＮＡ真核表达载体,用脂质体法转染高转移性人巨细胞肺癌细胞（ＰＧ）,经Ｎｏｒｔｈｅｍ杂交和Ｗｅｓｔｅｒｎ印迹免疫化学检测ＶＥＧＦ ｍＲＮＡ和蛋白质的表达水平,并对转染前后细胞进行体外生长和裸鼠体内生长转移等多项生物学行为实验,结果 转染反义转     

Inhibition of establishment of primary and micrometastatic tumors by a urokinase plasminogen activator receptor antagonist

Tumor establishment and metastasis are dependent on extracellular matrix proteolysis, tumor cell migration, and angiogenesis. Urokinase plasminogen activator (uPA) and its receptor are essential mediators of these processes. The purpose of this study was to investigate the effect of a recombinant human uPAR antagonist on growth, establishment, and metastasis of tumors derived from human cancer cell lines. A noncatalytic recombinant protein, consisting of amino acids 1-137 of human uPA and the CH2 and CH3 regions of mouse IgG₁ (uPA-IgG), was expressed, purified, and shown to bind specifically to human uPAR and to saturate the surface of human tumor cells which express uPAR. Daily i.p. administration of uPA-IgG to nude mice extended latencies of unstaged tumors derived from Lox melanoma and SW48 colon carcinoma cells by 7.7 and 5.5 days, respectively. uPA-IgG treatment did not affect the growth of Lox or KB tumors staged to 200 mg before antagonist treatment commenced. The effect of uPA-IgG on the establishment of micrometastases was assessed in SCID mice. KB head/neck tumor cells were injected in the tail vein and allowed to seed for 48 h before initiation of daily i.p. injections of uPA-IgG for 24 days. The number of lung colonies ranged between 5 and 30% of vehicle-treated mice in two separate experiments. Furthermore, a single 800 g dose of uPA-IgG administered 1 h prior to tail vein injection of KB cells reduced lung colony formation to just 3.5% of vehicle-treated SCID mice. These data demonstrate that antagonism of uPAR arrested metastasis and inhibited the establishment of primary tumors and micrometastases. Thus, small molecule uPAR antagonists may serve as useful adjuvant agents in combination with existing cancer chemotherapy. © Rapid Science 1998