EBC-1 Cells Research Articles

P51/p63, a novel p53 homologue, potentiates p53 activity and is a human cancer gene therapy candidate

p51 (p73L/p63/p40/KET), a recently isolated novel p53 homologue, binds to p53-responsive elements to upregulate some p53 target genes and has been suggested to share partially overlapping functions with p53. p51 may be a promising candidate target molecule for anti-cancer therapy. In this study, we adenovirally transduced p51A cDNA into human lung, gastric and pancreatic cancer cells and analyzed the intracellular function of p51 in anti-oncogenesis in vitro and in vivo. Overexpression of p51A revealed an anti-proliferative effect in vitro in all the cancer cells examined in this study. The anchorage-dependent and -independent cell growth of EBC1 cells carrying mutations in both p51 and p53 was suppressed and significant apoptosis following adenoviral transduction with p51 and/or p53 was seen. This growth suppression was cooperatively enhanced by the combined infection with adenoviral vectors encoding both p51 and p53. Furthermore, p51 activated several, but not all, p53-inducible genes, indicating that the mechanisms controlling p51- and p53-mediated tumor suppression differed. Our observations indicate that, although p51 exhibited reduced anti-oncogenetic effects compared with p53, it cooperatively enhanced the anti-tumor effects of p53. Our results suggest that p51 functions as a tumor suppressor in human cancer cells in vitro and in vivo and may be useful as a potential tool for cancer gene therapy.

Sodium butyrate up-regulates cathelicidin gene expression via activator protein-1 and histone acetylation at the promoter region in a human lung epithelial cell line, EBC-1

The antimicrobial protein cathelicidin is considered to play an important role in the defense mechanisms against bacterial infection. Recent studies show that sodium butyrate induces cathelicidin gene expression in human colonic, gastric and hepatic cells. However, little is known about the precise regulatory mechanisms underlying sodium butyrate-induced cathelicidin gene expression. In this study, we examined the regulatory mechanisms involved in sodium butyrate-induced cathelicidin gene expression using a human lung epithelial cell line, EBC-1. Our results indicate that sodium butyrate induces both cathelicidin mRNA and protein expression. Moreover, deletion or mutation of a putative activator protein-1 (AP-1) binding site in the cathelicidin gene promoter abrogated the response to sodium butyrate stimulation. Three different mitogen-activated protein (MAP) kinase inhibitors suppressed sodium butyrate-induced transactivation of the cathelicidin promoter. Electrophoretic mobility shift assays (EMSA) showed that nuclear extracts prepared from sodium butyrate-stimulated EBC-1 cells generated specific binding to probe including a putative AP-1 binding site in the cathelicidin gene promoter. Furthermore, chromatin immunoprecipitation (ChIP) assays demonstrated that sodium butyrate augmented histone acetylation of the cathelicidin promoter in EBC-1 cells. Therefore, these results indicate that AP-1 and histone acetylation of the cathelicidin promoter play a critical role in the regulation of inducible cathelicidin gene expression in EBC-1 cells stimulated with sodium butyrate.

E1B-deleted adenovirus replicates in p53-deficient lung cancer cells due to the absence of apoptosis

E1B55K adenovirus codes the protein that inactivates the p53 protein of host cells and facilitates its own cell proliferation. We prepared E1B55K-deleted adenovirus and investigated its cytopathic effects in primary lung cancer cells to evaluate the possibility of its application in gene therapy. A p53 wild-type small cell lung cancer cell line (SBC3) and three p53 mutant cell lines (SBC5, small cell lung cancer; PC3, adenocarcinoma; and EBC1, squamous cell carcinoma) were infected with AxE1AdB, in which the E1B55K gene was deleted, to assess the cytotoxicity and induction of apoptosis. Moreover, the mRNA expression in virus-infected cells was studied with cDNA array analysis to investigate the response of cancer cells to the virus infection. As a result, AxE1AdB had no detectable cytopathic effect on SBC3 cells, and SBC3 cells continued to replicate. In contrast, AxE1AdB killed SBC5, PC3, and EBC1 cells with great efficiency. In SBC3, apoptosis of the host cells was observed in the early infection stage; in the p53-mutant cell lines, apoptosis of the cells was restricted. An analysis of gene expression in the host cells indicated a significant increase of Bax mRNA in SBC3 and its deficiency in SBC5. Overall, our results suggest that AxE1AdB replicated selectively in the p53-mutant lung cancer cells and showed strong cytotoxicity against them. In the p53-intact cells, p53 induced apoptosis through Bax expression and prevented virus replication and escalation of the infection.

Overexpression of ADAM9 in non-small cell lung cancer correlates with brain metastasis.

The "a disintegrin and metalloprotease" (ADAM) family contributes to regulation of the cell-cell and cell-matrix interactions that are critical determinants of malignancy. To determine the relationship between metastasis and ADAM proteins, we compared the mRNA levels of ADAM9, -10, -12, -15, and -17 in sublines of an EBC-1 lung cancer cell line that were highly metastatic to either brain or bone. ADAM9 mRNA levels were significantly higher in highly brain-metastatic sublines than in the parent or highly bone-metastatic sublines. To elucidate the role of ADAM9 in brain metastasis, we stably transfected A549 and EBC-1 cells with a full-length ADAM9 expression vector. Compared with mock-transfectants, ADAM9 overexpression resulted in increased invasive capacity in response to nerve growth factor, increased adhesion to brain tissue, and increased expression of integrin alpha 3 and beta 1 subunits. Administration of the anti-beta 1 monoclonal antibody attenuated this increase in invasive and adhesive activity. Intravenous administration of ADAM9-overexpressing A549 cells to mice resulted in micrometastatic foci in the brain and multiple metastatic colonies in the lungs. In contrast, administration of parent and mock-transfected A549 cells to mice resulted in lung tumors without brain metastasis. These results suggest that ADAM9 overexpression enhances cell adhesion and invasion of non-small cell lung cancer cells via modulation of other adhesion molecules and changes in sensitivity to growth factors, thereby promoting metastatic capacity to the brain.

Induction of TNF-alpha, uPA, IL-8 and MCP-1 by doxorubicin in human lung carcinoma cells.

We have previously demonstrated doxorubicin-induced urokinase (uPA) and interleukin-8 (IL-8) expression in human H69 small-cell lung carcinoma (SCLC) cells by a microarray technique using Human Cancer Chip version 2, in which 425 human "cancer-related" genes are spotted on the plates. The microarray analysis also revealed a significant induction of tumor necrosis factor-alpha (TNF-alpha), and doxorubicin-induced macrophage chemoattractant protein-1 (MCP-1) expression was demonstrated by an RNase protection assay. We extended the study by testing the effects of doxorubicin on the induction of TNF-alpha, uPA, IL-8 and MCP-1 in other types of lung carcinoma cells. We investigated the effects of doxorubicin on the expression of TNF-alpha, uPA, IL-8 and MCP-1 in 12 human lung carcinoma cell lines, including five SCLC, three adenocarcinoma and four squamous cell carcinoma cells. The surface expression of their receptors was also investigated. TNF-alpha was significantly induced in three cell lines, H69, SBC-7 (SCLC) and PC-9 (adenocarcinoma), uPA in five cell lines, H69, SBC-7, EBC-1 (squamous cell), EBC-2 (squamous cell), and Sq-1 (squamous cell), IL-8 in three cell lines, H69, PC-9 and EBC-1, and MCP-1 in five cell lines, H69, SBC-3 (SCLC), SBC-7, PC-9 and Sq-1. In H69 cells, TNF-alpha antigen levels were increased approximately fivefold in the conditioned medium of doxorubicin-treated cells, in parallel with an increase in mRNA levels. As with uPA and IL-8, the maximum induction was observed at the "sublethal" concentrations of 2 and 4 microM at which cell growth was slightly inhibited 24 h after treatment. Furthermore, the cells did not express receptors including types I and II TNF-alpha receptors, uPA receptor (uPAR), C-x-C-chemokine receptor-1 (CXCR-1), or C-C-chemokine receptor-2, corresponding to TNF-alpha, uPA, IL-8 and MCP-1, respectively, that were induced by doxorubicin in the cells, although SBC-7 cells expressed uPAR, and EBC-1 cells expressed CXCR-1. TNF-alpha, uPA, IL-8 and MCP-1 induced and secreted from tumor cells upon doxorubicin stimulation may activate surrounding cells expressing the receptors such as neutrophils and monocytes/macrophages in a paracrine fashion. TNF-alpha is a major proinflammatory cytokine, and IL-8 and MCP-1 are major chemoattractants for neutrophils and monocytes/macrophages, respectively. Furthermore, uPA activates matrix metalloproteinase 9 which can truncate and activate IL-8. Thus, the simultaneous induction of TNF-alpha, uPA, IL-8 and MCP-1 may enhance the interaction between tumor and inflammatory/immune cells, and augment cytotoxicity.

A pulmonary metastatic model of human non-small cell lung carcinoma cells in SCID mice

We found that EBC-1, a human non-small cell lung cancer (NSCLC) cell line, formed multiple metastases in the lung after subcutaneous inoculation into severe combined immunodeficiency (SCID) mice. SCID mice were injected in the flank with 10 6 EBC-1 cells. Metastases in the lung were counted in histologic sections and stained immunohistochemically for neutrophil elastase (NE). Solid tumors were palpable in the flank at 3 weeks and grew steadily until 10 weeks. EBC-1 cells formed multiple metastases in the lung at 7 weeks; their numbers increased steadily until 12 weeks in all mice. Immunoreactivity for NE was intense in the metastatic tumor cells. As a marker for circulating tumor cells, human β-actin mRNA was detected in blood by reverse transcriptase–polymerase chain reaction (RT-PCR). Blood samples obtained at 3 weeks after tumor inoculation contained human β-actin mRNA. Our NSCLC EBC-1 pulmonary metastasis model is reliable, technically simple, and predictably results in pulmonary metastasis from early hematogenous spread. This model may be useful for screening potential new drugs, including specific NE inhibitors, for effectiveness against pulmonary metastasis of NSCLC.

A Pulmonary Metastatic Model of Human Non-small Cell Lung Carcinoma Cells That Produce a Neutrophil Elastase-Like Molecule in Severe Combined Immunodeficiency Mice

To establish a clinically relevant animal model of pulmonary metastases of human non-small cell lung carcinoma (NSCLC) cells in severe combined immunodeficiency (SCID) mice, which can be used for repetitive investigations, so as to improve our understanding and management of the cellular and molecular mechanisms of human lung cancer metastases. SCID mice subcutaneously injected in the flank with 1 x 10(6) EBC-1 cells derived from human lung squamous cell carcinoma were killed weekly for examination until 12 weeks after tumor inoculation. The biological characteristics of implanted tumors and their metastatic foci were investigated by hematoxylin-eosin staining and immunostaining for neutrophil elastase (NE). Three weeks after ectopic implantation, EBC-1 cell lines formed a tumor at the inoculation site and grew steadily to show a plateau at 10 weeks. EBC-1 cells formed multiple metastases in the lung 7 weeks after tumor inoculation; their numbers increased steadily until 12 weeks in all mice. Immunoreactivity for NE was intense in the metastatic tumor cells. Then, to establish the primary tumor amputation/pulmonary metastasis model and to evaluate how primary tumor amputation influences the development of pulmonary metastases at the cellular and molecular level, excision was performed before (3 weeks and 5 weeks after inoculation) and after (7 weeks and 9 weeks after inoculation) formation of lung metastases. When the primary tumor was excised 3 weeks after tumor inoculation, all mice had pulmonary metastasis at 12 weeks after inoculation. Blood samples obtained at 3 weeks after tumor inoculation contained human beta-actin messenger RNA, which represents circulating tumor cells. Our NSCLC EBC-1 pulmonary metastasis model is reliable, technically simple, and predictably results in pulmonary metastasis from early hematogenous spread. This model may be useful for elucidating the mechanism of pulmonary metastasis in human lung cancer, and testing anti-metastatic efficacy of therapeutic agents in vivo.

Hypoxia enhances the expression of plasminogen activator inhibitor-1 in human lung cancer cells, EBC-1.

Plasminogen activator inhibitor-1 (PAI-1) is one of the target genes of hypoxia inducible factor-1alpha (HIF-1alpha). Besides being an important physiological regulator of the fibrinolytic system PAI-1 is also involved in cancer invasiveness. HIF-1alpha is expressed in various types of pulmonary cells, but the relation of PAI-1 to HIF-1alpha under hypoxic condition in these cells are not fully elucidated. We, therefore, studied the effect of hypoxia on the expression of PAI-1 in a lung cancer cell line EBC-1. The expression of HIF-1alpha protein in EBC-1 cells was enhanced by hypoxia, and this was associated with increased secretion of PAI-1. Hypoxia did not affect the levels of HIF-1alpha mRNA but enhanced the PAI-1 mRNA. Pretreatment of the cells with MG132, which inhibits the proteasomal degradation of HIF-1alpha, increased the production of PAI-1 under both normoxia and hypoxia. We conclude that hypoxia induces PAI-1 expression, in EBC-1 cells, through the stabilization of HIF-1 complex and this may be related to cancer metastasis.

Augmentation of death ligand-induced apoptosis by aminopeptidase inhibitors in human solid tumor cell lines.

We previously reported that the aminopeptidase inhibitor bestatin induced apoptosis in several human leukemia cell lines. The present study was performed to examine whether bestatin can also induce apoptosis in solid tumor cell lines. Bestatin alone exhibited neither direct growth inhibition nor induction of apoptosis in the tumor cell lines examined. However, it significantly augmented the growth-inhibitory effect and induction of apoptosis by agonistic anti-Fas antibody (CH11). The augmentation by bestatin was also observed with other death ligands including tumor necrosis factor-alpha (TNF-alpha) in EBC-1 cells, a cell line sensitive to these death ligands. However, the HeLa S3 cell line, which is insensitive to TNF-alpha, showed no growth inhibition even by combination treatment. Bestatin methyl ester, a more cell-permeable derivative of bestatin with similar inhibitory activity to cytosolic neutral aminopeptidase, potentiated cell growth inhibition of CH11 more efficiently than bestatin. Other cytosolic neutral aminopeptidase inhibitors such as actinonin and puromycin also augmented cell growth suppression by CH11, while an enantiomer of bestatin lacking aminopeptidase inhibitory action did not increase the growth-inhibitory effects of CH11. The combination of 10 microg/ml of bestatin with CH11 promoted processing of caspase 3 to the active form p17 and efflux of mitochondrial cytochrome c into the cytosol more quickly and more intensely than CH11 alone. Inhibition of aminopeptidase was not involved in dATP- and cytochrome c-dependent caspase 3-activation in a cell-free system. Bestatin significantly augmented activation of caspase 8, which is upstream of cytochrome c efflux in the apoptosis cascade. These results suggested that intracellular neutral aminopeptidase might play an important role in Fas- or TNF-alpha-induced solid tumor cell apoptosis.

Cloning of differentially expressed sequence tags from nickel-transformed human embryonic lung cells

Differential display polymerase chain reaction (DD-PCR) was used to analyze the differentially expressed genes from nickel-transformed human embryonic lung (HEL) cells (MRC-9 and IMR-90) and their control counterparts (non-treated). Two genes, MS515 and IC82, were confirmed by Northern blot analysis. MS515 was detected in control and nickel oxide (NiO)-transformed MRC-9 cells, as well as in non-small cell lung cancer (NSCLC) EBC-1 cells, while very weak expression was observed in nickel subsulfide (Ni3S2)-transformed MRC-9 cells and small cell lung cancer (SCLC) SBC-2 cells. IC82 could not be detected in control IMR-90 cells, while it was expressed in EBC-1 cells and NiO- and Ni3S2-transformed IMR-90 cells. These findings indicate that individual nickel compounds have their own target gene(s) in inducing lung cancer. Sequencing analyses showed that the MS515 gene shared a high degree of homology (over 80%) with the gene Mena, which is involved in actin polymerization. IC82 showed 99% homology with human chromosome 4 clone C0440E08 and a coding sequence in the brain. The roles of these two genes in nickel carcinogenesis will be discussed.

Vesnarinone and glucocorticoids cooperatively induce G1 arrest and have an anti-tumour effect on human non-small cell lung carcinoma cells grown in nude mice

Vesnarinone, an oral cardiotonic, inhibited the growth of several human non-small cell lung carcinoma cell lines, and its anti-proliferative effects in vitro and in vivo were greatly enhanced by combination with glucocorticoids, but not other steroids. Simultaneous treatment with vesnarinone and dexamethasone is the most effective to evoke the synergistic effect in the growth inhibition of lung carcinoma EBC-1 cells. Dexamethasone and other glucocorticoids induced morphological changes in EBC-1 cells and these agents together with vesnarinone induced alkaline phosphatase activity, which is a typical marker of type II pneumocyte maturation. This treatment arrested the growth of the cells at the G1 phase, indicating that this treatment is cytostatic rather than cytotoxic. These results suggest that vesnarinone plus glucocorticoid might be useful in lung cancer therapy. © 1999 Cancer Research Campaign

Granulocyte-macrophage-colony stimulating factor stimulates tumor invasiveness in squamous cell lung carcinoma

Bronchial epithelial cells produce a significant amount of granulocyte-macrophage-colony stimulating factor (GM-CSF), which is believed to mediate both the host defense and inflammation. Recently, GM-CSF has been demonstrated to be produced by several tumor cells and also to be associated with tumor growth and metastasis. In the current study, the authors investigated the biologic role of GM-CSF produced by squamous cell lung carcinoma. The production of GM-CSF from 17 human lung carcinoma cell lines was determined by an enzyme-linked immunoabsorbent assay. In vitro invasiveness was investigated by using a Biocoat Matrigel (Collaborative Biomedical Products, Bedford, MA) precoated invasion chamber. The activity of the matrix metalloproteinases (MMPs) were examined by gelatin zymography. The expression of GM-CSF in 113 cases of resected nonsmall cell lung carcinoma was analyzed immunohistochemically, and the association between the expression of GM-CSF and clinicopathologic features was investigated. The production of GM-CSF by squamous cell carcinoma cell lines was closely related to the in vitro invasiveness and MMP activity of the cancer cells. Recombinant GM-CSF stimulated the invasiveness of less invasive LK-2 and LC-1 cells in a dose-dependent manner, and this stimulation was abrogated by the neutralizing anti-GM-CSF antibody. Furthermore, anti-GM-CSF antibody decreased the invasiveness of highly invasive EBC-1 and NCI-H157 cells. GM-CSF also increased the MMP activity of LK-2 and LC-1 cells. Of 113 resected nonsmall cell lung carcinomas, 30 of 71 squamous cell carcinomas (42.3%), and 24 of 42 adenocarcinomas (57.1%) stained positively for GM-CSF. The expression of GM-CSF in squamous cell carcinomas was associated with the local invasion by the primary tumor. These results suggest that the production of GM-CSF is involved in both the in vitro invasiveness and the local progression of squamous cell carcinoma of the lung.

Expression and roles of lumican in lung adenocarcinoma and squamous cell carcinoma

Lumican is a member of a small leucine-rich proteoglycan family and is highly expressed in several types of cancer cells and/or stromal tissue. Lumican expression in the cytoplasm in advanced colorectal cancer correlates with poor patient prognosis. The expression of lumican in stromal tissues is associated with a high tumor grade, a low estrogen receptor expression level, and young age in breast cancer and is associated with tumor invasion and advanced stage in pancreatic cancer. In this study, we examined the expression and role of lumican in lung cancer including adenocarcinoma (ADC) and squamous cell carcinoma (SqCC). Immunohistochemically, lumican was weakly expressed in vascular smooth muscle cells, perivascular and peribronchial connective tissues and bronchial epithelium of normal lung tissues. In lung cancer tissues, lumican was localized in the cytoplasm of cancer cells and/or stromal tissues adjacent to cancer cells. In ADC, the expression level of lumican in cancer cells correlated with pleural invasion and larger tumor size, but that of lumican in stromal tissues did not correlate with clinicopathological factors. In SqCC, the expression level of lumican in cancer cells correlated with formation of a keratinized pattern, and stromal lumican expression correlated with vascular invasion. In SqCC and ADC, the expression level of lumican in cancer cells did not correlate with patient prognosis. In lung cancer cell lines, lumican mRNA and protein were expressed in LC-1/Sq and EBC-1 cells established from SqCC, and A549, RERF-LC-KJ and PC-3 cells from ADC. The molecular weight of lumican extracted from the cytoplasm of lung cancer cells differed from that in the culture medium owing to glycosylation of the protein. These findings suggest that the expression pattern and the glycosylated type of lumican in cells and stromal tissues correlate with the aggressiveness of lung SqCC and ADC.

肺扁平上皮癌の治療に関する研究

The effectiveness of hyperthermia in combination with anticancer drugs on EBC-1 cell line established from a patient with pulmonary epidermoid carcinoma was investigated. Anticancer drugs tested in the present study were adriamycin, bleomycin, cisdichlorodiammineplatinum (II) and mitomycin C. EBC-1 cells were incubated with the drug for one hour at 37°C or at elevated temperature (41°C, 42°C and 43°C). The enhancement of cytotoxicity by hyperthermia was found in combination with all of the drugs. The degree of enhanced cytotoxicity was positively elated to the temperature in combinations with adriamycin and bleomycin. Especially, a synergic enhancement of cytotoxicity was found with the combination of hyperthermia and bleomycin. The present study showed that the combination of hyperthermia and anticancer drugs produced potential cytotoxicity on EBC-1 cells in vitro, and may provide useful information for the clinical trials in the future.