非小细胞肺癌患者肺组织环氧合酶-2表达的变化及其临床意义

目的探讨非小细胞肺癌(NSCLC)患者肺组织中环氧合酶-2(COX-2)的表达和血浆PGE 2含量的变化及其与临床病理参数之间的关系.方法采用逆转录聚合酶联反应(RT-PCR)和放射免疫法,分别检测38例NSCLC患者和正常健康者肺组织中COX-2 mRNA的表达以及血浆PGE 2含量的变化.结果 38例肺癌患者肺癌组织和正常肺组织中分别有34例和3例检测到COX-2 mRNA表达,阳性表达率分别为13.16%和89.47%;半定量分析肺癌组织中的COX-2 mRNA平均吸光度显著高于正常肺组织(P＜0.001).肺癌患者和正常健康者血浆中PGE 2浓度分别为(42.33±6.13)μg/L和(5.87±1.40)μg/L,二者比较,差异亦具有显著性(P＜0.01).直线相关分析肺癌组织中COX-2 mRNA的表达和PGE 2浓度的变化呈正相关(r=0.552,P＜0.05).COX-2 mRNA表达在不同性别、年龄、组织分型、TNM分期和分化程度之间差异分别均无显著性(P＞0.05).结论 NSCLC患者肺癌级织中COX-2 mRNA和PGE 2表达增强,可能在NSCLC的发生和发展中具有重要作用.     

Expansion of human T regulatory type 1 cells in the microenvironment of cyclooxygenase 2 overexpressing head and neck squamous cell carcinoma

Cyclooxygenase 2 (COX-2) overexpression and production of prostaglandin E(2) (PGE(2)) by head and neck squamous cell carcinomas (HNSCC) induce type 1 regulatory T (Tr1) cells and contribute to carcinogenesis by creating a tolerogenic milieu. To test this hypothesis, CD4(+)CD25(-) T cells obtained from the peripheral blood of 10 normal donors were cocultured with autologous dendritic cells, irradiated HNSCC cells and cytokines, interleukin 2 (IL-2), IL-10, and IL-15. HNSCC cells were either COX-2 negative, constitutively expressed COX-2, were transfected with COX-2, or had COX-2 expression knocked down by small interfering RNA. Other modifications included coculture plus or minus the COX-inhibitor, Diclofenac, or synthetic PGE(2) in the absence of HNSCC. Lymphocytes proliferating in 10-day cocultures were phenotyped by flow cytometry, studied for cytokine production by ELISA and for suppressor function in CFSE inhibition assays plus or minus anti-IL-10 or anti-transforming growth factor-beta(1) (TGF-beta(1)) monoclonal antibodies (mAb). COX-2(+) HNSCC or exogenous PGE(2) induced outgrowth of Tr1 cells with the CD3(+)CD4(+)CD25(-)IL2Rbeta(+)IL2Rgamma(+)FoxP3(+)CTLA-4(+)IL-10(+)TGF-beta(1)(+)IL-4(-) phenotype and high suppressor functions (range, 46-68%). Small interfering RNA knockout of COX-2 gene in HNSCC led to outgrowth of lymphocytes with decreased IL2Rgamma (P = 0.0001), FoxP3 (P = 0.05), and IL-10 (P = 0.035) expression and low suppressor activity (range, 26-34%). Whereas COX-2(+) cocultures contained IL-10 and TGF-beta(1) (medians, 615 and 824 pg/mL), cytokine levels were decreased (P < 0.0001) in COX-2(-) cocultures. Inhibition of COX-2 enzymatic activity in HNSCC abrogated outgrowth of Tr1 cells. Neutralizing mAbs to IL-10 and/or TGF-beta(1) abolished Tr1-mediated suppression. COX-2 overexpression in HNSCC plays a major role in the induction of Tr1 cells in the tumor microenvironment.     

Mutation and functional analysis of IL-13 receptors in human malignant glioma cells

We have previously demonstrated that human brain tumor cells, in particular glioblastoma multiforme (GBM), express abundant receptors for interleukin-13 on the cell surface. These receptors are composed of IL-13 receptor (IL-13R)alpha1, IL-13Ralpha2, and IL-4Ralpha chains. The significance of overexpression of IL-13R on tumor cells is not known. Because expression of IL-13R on glioma cells is an unexpected phenomenon, we examined whether these receptors are polymorphic. Therefore, we analyzed cDNA for IL-13Ralpha1 and IL-13Ralpha2 chain genes by PCR-based single-strand conformation polymorphism and direct sequencing techniques for a possible polymorphism in 19 GBM, one normal human astrocyte, and two fibroblast cell lines. All analyzed samples except normal astrocytes overexpressed IL-13Ralpha2; however, none of these cell lines showed a mutation in cDNA for IL-13Ralpha2 chain. In contrast, all GBM samples, normal astrocytes, and fibroblasts expressed mRNA for IL-13Ralpha1 with apparent single nucleotide polymorphism in the transmembrane domain. To study the function of IL-13R on brain tumor cells, we investigated the regulation of adhesion molecules by IL-13 as assessed by flow cytometric analysis. A172 cell line expressed a low level of vascular cell adhesion molecule-1 (VCAM-1), while U251 and LA1-5g cell lines expressed intercellular adhesion molecule-1 (ICAM-1). On the other hand E-selectin was not expressed in any cell lines. Interestingly, IL-13 increased the expression level of VCAM-1 in A172 cell line in a dose- and time-dependent manner. However, IL-13 did not modulate any other adhesion molecules. These results suggest that IL-13R on GBM cells are not rearranged but appear to be functional.     

In situ expression of interleukin-4 (IL-4) receptors in human brain tumors and cytotoxicity of a recombinant IL-4 cytotoxin in primary glioblastoma cell cultures.

We have reported that human malignant glioma cell lines express high levels of plasma membrane interleukin-4 receptors (IL-4R). We have also reported that biopsy/surgical samples or primary explant cell cultures from brain tumors express mRNA and protein for the IL-4Ralpha chain, a primary IL-4-binding protein. However, whether IL-4R are expressed in brain tumors in situ has not been resolved. In addition, expression of IL-4R on the cell surface of various normal brain tissues is not known. We examined the expression of IL-4R by using a monoclonal antibody to the IL-4Ralpha chain (also known as IL-4R beta) in surgical/biopsy samples of brain tumor tissues by immunohistochemistry. Our data indicate that 15 of 18 glioblastoma multiforme (GBMs) tumors obtained from two different institutions and 12 other brain tumor samples are moderately to intensely positive for IL-4Ralpha. In contrast, although IL-4Ralpha mRNA was expressed, no IL-4R protein was detectable in two adult and one pediatric brain tissue specimens. In addition, a commercially available human neural tissue grid containing fixed tissues from various areas of brain showed no positive staining for the IL-4Ralpha chain. IL-4Ralpha expression was also demonstrated on astrocytoma grades I, II, and III. Because IL-4 cytotoxin comprised of a circularly permutated IL-4 and a mutated form of Pseudomonas exotoxin [IL4(38-37)-PE38KDEL] is cytotoxic to IL-4R-expressing cells, we tested whether primary GBM explant cell cultures are sensitive to IL-4 cytotoxin. Our data indicate that 13 of 15 GBM cell cultures were 25-74 times more sensitive to IL-4 cytotoxin compared with normal human astrocytes or the NT2 neuronal cell line. These observations indicate that human brain tumors in situ overexpress IL-4R compared with normal brain tissues, thus confirming our previous conclusions that IL-4R in brain tumors may serve as an attractive target for anticancer therapy.     

EGFR、VEGF和COX-2在非小细胞肺癌中的表达和意义

目的探讨EGFR、VEGF和COX-2这三种与肿瘤血管生成相关的蛋白在非小细胞肺癌（NSCLC）中的表达及其与临床病理特征的关系。方法选取73例青年NSCLC标本和65例老年NSCLC标本,与10例肺良性肿瘤组织及10例正常肺组织标本一起制作成组织芯片,应用免疫组化S-P法检测EGFR、VEGF和COX-2的表达,并与临床参数进行比较分析。结果EGFR、VEGF和COX-2在NSCLC标本中的阳性表达率分别为51.4%、73.2%和44.9%。10例肺良性肿瘤组织中有2例VEGF阳性,2例COX-2阳性;而10例正常肺组织中三者表达均为阴性。EGFR阳性表达在男性、吸烟者、鳞癌和无淋巴结转移患者中明显升高（P〈0.05）,VEGF表达与各种临床病理特征均无关（P〉0.05）,COX-2阳性表达在腺癌患者中明显升高（P=0.000）。三者表达与年龄分组均无关。EGFR和VEGF呈正相关关系（r=0.198,P=0.02）。结论EGFR、VEGF和COX-2在NSCLC中表达升高,在青年和老年肺癌标本中表达无差异;EGFR和VEGF在NSCLC肿瘤血管形成过程中可能起协同作用。     

Increase of carcinogenic risk via enhancement of cyclooxygenase-2 expression and hydroxyestradiol accumulation in human lung cells as a result of interaction between BaP and 17-beta estradiol

Animal studies demonstrated that females are more susceptible than males to benzo[a]pyrene (BaP)-induced toxicities, including lung carcinogenesis. Elevation of cyclooxygenase-2 (COX-2) expression has been shown to increase the risk of cancer development. BaP induces COX-2 expression, and an interaction between BaP and estrogen in relation to COX-2 expression is suspected. In the present study, 10 muM BaP alone only slightly increased COX-2 mRNA expression and 10 nM 17-beta estradiol (E(2)) alone slightly increased prostaglandin E2 (PGE2) secretion in human bronchial epithelial cells. However, co-treatment with BaP and E(2) potentiated COX-2 mRNA expression and significantly elevated PGE2 secretion. Utilizing specific inhibitors and reporter assays, we further investigated the potentiation mechanisms of E(2) on BaP-induced COX-2 expression. First, E(2) activated estrogen receptor to increase PGE2 secretion, which directly increased COX-2 expression. Second, E(2) potentiated BaP-induced nuclear factor-kappaB (NF-kappaB) activation, which regulates COX-2 expression. Third, although the aryl hydrocarbon receptor (AhR) did not play a role in BaP-induced COX-2 expression, the potentiation effect of E(2) itself was AhR dependent. We further demonstrated that BaP induced the production of genotoxic E(2) metabolites (2- and 4-hydroxyestradiols) via AhR-up-regulated cytochromes P450 1A1 and 1B1. These metabolites could directly activate NF-kappaB to further promote COX-2 mRNA expression in human lung epithelial cells. These findings were further supported by increased PGE2 secretion in rat lung slice cultures. Our findings that the BaP-E(2) interaction enhanced COX-2 expression and hydroxyestradiol accumulation in the media of cultivated lung cells and tissues provide the needed scientific basis for higher risk of BaP-associated lung cancer in females.     

PGE2-mediated upregulation of iNOS in murine breast cancer cells through the activation of EP4 receptors

We report here that endogenous prostaglandin E(2) (PGE(2)) resulting from cyclooxygenase (COX)-2 expression in a highly metastatic murine breast cancer cell line C3L5 upregulates IFN-gamma + LPS-induced nitric oxide (NO) synthase (iNOS) expression and NO production. This action of PGE(2) is mediated through the EP(4) receptor in a cAMP-dependent manner. Both nonselective and selective COX-2 inhibitors suppressed IFN-gamma + LPS-induced NO production, which was largely restored by exogenous PGE(2) or EP(4) receptor agonist PGE(1) alcohol. EP(4) antagonist AH-23848B inhibited NO production with a concomitant downregulation of iNOS mRNA in IFN-gamma + LPS-stimulated cells. cAMP dependence of NO production by cells under inducible conditions was demonstrated by the use of known modulators of intracellular cAMP. Since both COX-2 and iNOS are implicated in breast cancer progression, our findings of EP(4) receptor-mediated upregulation of iNOS in COX-2-expressing breast cancer cells suggest that blocking COX-2 and/or EP(4) may provide a simple therapeutic modality in this tumor model.     

Interleukin-13 receptor alpha2 chain in human head and neck cancer serves as a unique diagnostic marker.

Previous studies have demonstrated that approximately 30% of squamous cell carcinoma of the head and neck (SCCHN) cell lines express high levels of interleukin-13 receptor(s) (IL-13R). However, the incidence, expression level, and significance of IL-13R expression in human tumor specimens is not known. In addition, it is not known whether normal head and neck tissues express IL-13R. In this study, we evaluated the expression of IL-13R subunits (IL-13Ralpha1, IL-13Ralpha2, and IL-4Ralpha) in 337 surgically excised specimens of SCCHN and normal head and neck tissues. Specimens were obtained from 139 patients with SCCHN and 16 patients with benign tonsil disorders from two centers in the United States and Japan and evaluated with immunohistochemistry and in situ hybridization. Extensive analysis demonstrated that the majority of SCCHN tumors uniformly expressed low levels of IL-13Ralpha1 chain; however, 77% of the tumors expressed moderate to high levels of IL-4Ralpha, which forms a signaling complex with IL-13Ralpha1 chain. On the other hand, 33% of SCCHN tumors expressed moderate to high levels of IL-13Ralpha2 chain. Using tissue array from 99 patients, we observed that the expression levels of IL-13Ralpha2 and IL-4Ralpha were significantly higher in SCCHN than in normal head and neck tissues (P < 0.005). Detailed analysis of clinicopathological features demonstrated a positive statistically significant correlation between IL-13Ralpha2 expression and clinically advanced primary SCCHN tumor (T(4); Tumor-Node-Metastasis classification; P < 0.05). However, there was no correlation among IL-13R expression and sex, age of patients, stage of lymph node metastasis, squamous cell carcinoma grade, or allergic history. Taken together, this study suggests that IL-13R may be involved in SCCHN tumor progression, and 33% of IL-13Ralpha2-positive SCCHN cases may be targeted by IL-13 cytotoxin and IL-13R-targeted agent.     

Prostaglandin E2 activates mitogen-activated protein kinase/Erk pathway signaling and cell proliferation in non-small cell lung cancer cells in an epidermal growth factor receptor-independent manner

Cyclooxygenase 2 (COX-2) overexpression is found in a wide variety of human cancers and is linked to all stages of tumorigenesis. Elevated tumor COX-2 expression is associated with increased angiogenesis, tumor invasion, suppression of host immunity and promotes tumor cell resistance to apoptosis. Previous reports have linked the COX-2 product prostaglandin E2 (PGE2) to the abnormal activation of the mitogen-activated protein kinase/Erk kinase pathway. Here we show that PGE2 is able to rapidly stimulate Erk phosphorylation in a subset of non-small cell lung cancer (NSCLC) cell lines. This effect is not evident in bronchial epithelial cells. In contrast to previous reports in colon cancer, we found that Erk activation as well as cellular proliferation induced by PGE2 was not inhibited by pretreatment of the cells with epidermal growth factor receptor (EGFR) inhibitors. Activation of the Erk pathway by PGE2 was also resistant to src kinase inhibitors but sensitive to the protein kinase C inhibition. PGE2 effects are mediated through four G protein-coupled receptors. Selective inhibition of EP receptors revealed the possible involvement of Ca2+-dependent signaling in PGE2-mediated activation of Erk. Our data indicate the presence of an EGFR-independent activation of the mitogen-activated protein kinase/Erk pathway by PGE2 in NSCLC cells. These findings provide evidence for the possible link between tumor COX-2 overexpression and elevated Erk-mediated cancer cell proliferation and migration. Importantly, these findings suggest that COX-2 overexpression may contribute to EGFR inhibitor resistance in NSCLC.     

Phosphoglycerate kinase 1-overexpressing lung cancer cells reduce cyclooxygenase 2 expression and promote anti-tumor immunity in vivo

In addition to the known function in the glycolytic pathway, phosphoglycerate kinase 1 (PGK-1) promotes reduction of plasmin disulfide bonds leading to angiostatin formation and inhibition of tumor angiogenesis. In this study, the effects of PGK-1 on anti- tumor immunity against lung cancer were evaluated using the Tet-Off control of PGK-1 expression in the Lewis lung carcinoma (LLC-1). There was no significant difference in cell proliferation between parental LLC-1 and LLC-1 transduced with PGK-1 (PGK-LLC-1). However, expression of PGK-1 was found to limit tumor growth in mice subcutaneously injected with the cell lines and tumor growth was restored after doxycycline treatment. In addition, the cell invasion ability of PGK-LLC-1 became weaker than that of LLC-1. Expressions of COX-2, TGF-beta1 and PGE2 were all found to be down-regulated in PGK-LLC-1. PGK-LLC-1 cells treated with doxycycline recovered their COX-2 protein expression. In the presence of conditioned medium from PGK-LLC-1, the endothelial cell migration was reduced. Moreover, PGK-LLC-1 also stimulated T lymphocytes to express higher levels of Th1 cytokine (IFN-gamma) and lower levels of IL-10 in comparison with parental LLC-1. PGK-LLC-1 cells restored the growth rate in immunodeficient mice when compared with the growth rate in normal mice. In the tissue sections, reduced COX-2 expressions and marked infiltrated CD3 T lymphocytes were observed in the PGK-LLC-1 injected group. These findings indicate that overexpression of PGK-1 in LLC-1 reduces the COX-2 expression, and, in turn, affect PGE2, cell invasion, angiogenesis, and the immune functions, and finally inhibit the tumor progression.     

Correlation between cyclooxygenase-2 and tumor angiogenesis in non-small cell lung cancer

The role of COX-2 expression and angiogenesis of lung cancer is yet to be delineated. Eighty four non-small cell lung cancer (NSCLC) specimens were evaluated for COX-2 expression, microvessel density (MVD), and vascular endothelial growth factor (VEGF) expression by immunohistochemical methods. The relationships between COX-2 expression and MVD, VEGF expression, and survival time were analyzed. COX-2 expression was observed in the cytoplasm and membrane of the carcinoma cells, and premalignant cells. COX-2 was positive in 67 cases (79.8%). There was a statistically significant correlation between COX-2 expression and tumor size, TNM stage, tumor type, VEGF expression, and vascular pattern with survival in univariate analysis. No significant correlation was seen between COX-2, VEGF expression and MVD. A lack of expression of either COX-2 or VEGF expression or both, however, was associated with lower MVD than the group with both expressed. The difference was statistically significant (P=0.005). Statistically significant differences were also observed according to TNM stage, vascular pattern, COX-2 expression, and VEGF expression. With multivariate analysis, only TNM stage and COX-2 expression retained their significance as independent predictors of survival. COX-2 expression takes part in tumor angiogenesis and is a significant poor prognostic factor in the surgically resected NSCLC. COX-2 inhibitor, either in combination therapy with other agents, or for chemoprevention, may be effective via suppression of angiogenesis in this fatal disease.     

Effect of prostaglandin E1 on vascular endothelial growth factor production by human macrophages and colon cancer cells

We previously demonstrated that cyclooxygenase-2 (COX-2) was predominantly expressed in macrophages of sporadic human colonic adenomas; however, the role of COX-2-expressing cells during colon carcinogenesis has not yet been elucidated. In the present study, we showed the effect of PGE, on vascular endothelial growth factor (VEGF) production by PMA-differentiated U937 cells, a human macrophage model (H-Mac), and by human colon cancer cells T84. PGE1 dramatically induced VEGF production by H-Mac, but not that by T84. PGE1 significantly increased intracellular cAMP formation by H-Mac, but only modestly increased that by T84. 8-bromo-cAMP and cholera toxin also increased VEGF production by H-Mac. In contrast, neither of these agents modulated VEGF production by T84. EP2 and EP4 (PGE specific receptors) mRNA was expressed in both cells. PG dramatically increased VEGF production by activated macrophages, but not by cancer cells, through a specific PGE receptor-mediated process. These findings suggest that PGs produced by COX-2-expressing macrophages induce VEGF production by macrophages, but not by cancer cells, in an autocrine fashion.     

Cyclooxygenase-2, malondialdehyde and pyrimidopurinone adducts of deoxyguanosine in human colon cells

Cyclooxygenases (COX) catalyse the oxygenation of arachidonic acid to prostaglandin (PG) endoperoxides. Activity of one of the COX isoforms, COX-2, results in production of prostaglandin E(2) (PGE(2)) via the endoperoxide PGH(2). COX-2 has been implicated in the pathogenesis of colorectal cancer. Malondialdehyde (MDA) is a mutagen produced by spontaneous and enzymatic breakdown of PGH(2). MDA reacts with DNA to form adducts, predominantly the pyrimidopurinone adduct of deoxyguanosine (M(1)G). Here the hypothesis was tested that COX-2 activity in human colon cells results in formation of MDA and generation of M(1)G adducts. M(1)G was detected in basal cultures of human non-malignant colon epithelial (HCEC) and malignant SW48, SW480, HT29 and HCA-7 colon cells, at levels from 77 to 148 adducts/10(8) nucleotides. Only HCA-7 and HT29 cells expressed COX-2 protein. Levels of M(1)G correlated significantly (r = 0.98, P < 0.001) with those of intracellular MDA determined colorimetrically in the four malignant cell types, but neither parameter correlated with expression of COX-2 or PG biosynthesis. Induction of COX-2 expression by phorbol 12-myristate 13-acetate in HCEC cells increased PGE(2) production 20-fold and MDA concentration 3-fold. Selective inhibition of COX-2 activity in HCA-7 cells by NS-398 significantly inhibited PGE(2) production, but altered neither MDA nor M(1)G levels. Malondialdehyde treatment of HCEC cells resulted in a doubling of M(1)G levels. These results show for the first time in human colon cells that COX-2 activity is associated with formation of the endogenous mutagen, MDA. Moreover, they demonstrate the correlation between MDA concentration and M(1)G adduct levels in malignant cells.